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Surgical excision of Morton’s neuroma: Does it provide a reliable outcome?

Posted on June 30, 2019 | Comments Off on Surgical excision of Morton’s neuroma: Does it provide a reliable outcome?

by Muhammad Murtaza Khan1*, and Dakshinamurthy Sunderamoorthy2

The Foot and Ankle Online Journal 12 (2): 5

This study involves a retrospective analysis of the surgical intervention for treatment of Morton’s neuroma of the foot for patients that were treated over three years period. The aim of this study is to evaluate the long-term outcome following operative removal of the Morton’s neuroma of foot using MOXFQ. We retrospectively evaluated the outcome of 13 patients (14 feet) who were operated from February 2015 to March 2018 for excision of Morton’s neuroma using a dorsal approach. We evaluated the outcome was using clinical follow up notes, examination findings and the Manchester Oxford Foot Questionnaire score. Thirteen patients (14 feet) were operated during this period, out of which 12 were females and one male with a mean age of 58 years. One patient had bilateral symptomatic disease. 11 out of 13 patients (84.6 %) were satisfied with their results of surgery after a mean follow-up period of 34.42 ± 9.81 months. Biopsy supported the clinical diagnosis in 13/14 case (92.857%). Preoperative diagnosis was confirmed by radiologist as Morton’s neuroma on 12/14 cases (85.71%). The predominant modality of choice was ultrasound of feet, however, MRI of the foot was advised in one case only. Statistically significant difference was appreciated between preoperative and postoperative MOXFQ score (41.92 ± 10.47 verses 8± 15.11), respectively, with a p value < 0.0001 CI 95% SI 4.913. Our study shows surgical excision of Morton’s neuroma is a reliable procedure and it gives a good outcome and it is maintained over a period of 3 years.

Keywords: Morton’s neuroma, MOXFQ, dorsal approach

ISSN 1941-6806
doi: 10.3827/faoj.2018.1202.0005

1 – 6 Saxby House Church lane Scunthorpe (DN15 7HY)
2 – Northern Lincolnshire and Goole Foundation NHS Trust (DN15 7BH)
* – Corresponding author: Murtazakhan142@yahoo.com

Morton’s neuroma is non-malignant enlargement of the common plantar digital nerve, usually seen at the 2nd or 3rd intermetatarsal spaces [1,2]. It is one of the most common causes of metatarsalgia and majority of clinicians consider the clinical diagnosis as an indication to treatment [3]. Morton’s neuroma should be considered as part of differential diagnosis in any patient complaining of forefoot pain [5]. The most common presenting complaint is burning pain on the plantar aspect of the foot between the metatarsal heads of corresponding toes [3]. Others complain of walking on a lump on the ball of the great toe, shooting pain and tingling in the involved digits [5]. Pain is particularly aggravated by walking and wearing tight shoes and is relieved by rest [3]. Researchers were not able to identify the definitive cause of this condition. Some consider it due to hypermobility of 4th ray over the cuboid as part of the etiology, explaining why the third metatarsal space is commonly associated with the disease [3].

It may also be due to entrapment of nerve at the distal metatarsal ligament or may be due to trauma, equinus deformity or autonomic neuropathy [5]. Considering the variable presentation of patient symptoms, the modality of choice and surgical approach is also subjected to active debate over the years. Surgery is considered the treatment of choice with either dorsal or plantar approach. However, few consider equal efficacy of either dorsal or plantar approach for excision [7]. Others considered dorsal approach only in cases of recurrent disease [8].

Some advocate conservative treatment as part of regimen. However, it is associated with variable success rate and many patients ultimately underwent surgery after initial period of successful non-surgical management. Moreover, the role of corticosteroids with local anesthetic is also considered futile in long term follow-up [1] (6 months). 

The use of histology was considered as an essential part of postoperative work-up for consideration of the diagnosis, however, others considered it as an economic burden unless it is a recurrent disease or ambiguity regarding diagnosis during surgery [5].

Materials and Methods 

We retrospectively evaluated our thirteen cases (fourteen feet) from 2015 to 2018 and the postoperative outcome was evaluated using Manchester Oxford Foot and Ankle Questionnaire. All patients with neuroma were considered for the study. Any patient with recurrent disease, diagnosed case of other foot pathology like rheumatoid arthritis, associated injuries in the metatarsophalangeal joint, any patient operated for recurrent disease or not willing to answer the questionnaire over the phone were excluded from the study. In order to avoid any bias during study we evaluated the patient outcome following surgery not only through clinical notes, radiology reports (USG/ MRI) histopathology but also used operative summaries. Moreover, additional information was extracted by ringing the patients using their documented contact numbers and after taking verbal consent we asked question as in MOXFQ, thus cross checking the information provided in the post-operative follow up pathway in terms of patient satisfaction/ dissatisfaction status. 

Figure 1 Patient demographics.

Figure 2 Management characteristics.

The results were evaluated by calculating the mean, standard deviation, standard error for values obtained. For evaluation whether the pre and post-operative MOXFQ score is statistically significant we calculated the p value using the mean values of pre and post-operative MOXFQ score.  P value <0.05 was considered as significant.  

Results

Thirteen patients (14 feet) were operated during this period, out of which 12 were females and one male with a mean age of 58 years (Figure 1). Fifty percent (7/14) were operated in 2014. Thirty six percent (5/14) in 2016. Seven percent in both 2017 & 2018 (1/14) in each year.  One patient had bilateral symptomatic disease. Eight out of 14 cases (57%) have disease confined to third metatarsal space and 6/14 cases (43%) have disease in second metatarsal space. Eleven out of 13 patients (84.6 %) were satisfied with their results of surgery after a mean follow up period of 34.42 ± 9.81 months. 

Biopsy supported the clinical diagnosis in 13/14 cases (92.85%). Preoperative diagnosis was confirmed by radiologist as Morton’s neuroma on 12/14 cases (85.71%). The predominant modality of choice was ultrasound of feet (Figure 3). 

Figure 3 Method of diagnosis.

Figure 4 Pre- and postoperative MOXFQ scores.

However, MRI foot was advised in one case only. Conservative treatment was opted by 5/14 patients (35%). Out of these one was offered injection of local anesthetic with corticosteroid in clinic and 4/14 (28.5%) were given ultrasound guided injection of local anesthetic with steroid. However, the mean relief period was 1.22± 2.2 months for all 5 patients and they ultimately opted for surgery (Figure 2). Statistically significant difference was appreciated between pre-operative and post-operative MOXFQ score (41.92 ± 10.47 Verses 8± 15.11) respectively with p value < 0.0001 CI 95% SI 4.913 (Figure 4).

Discussion

Our results showed a patient satisfaction rate of 84.6%, which is higher than the documented success rate of surgery. It is variably reported in literature however, it never exceeds 80% [1]. Some researchers have raised concerns regarding the use of dorsal approach for surgery compared to the plantar approach, but our results do not support this argument. In fact, we were able to treat our patient with satisfactory results using a dorsal approach.

The literature supports the use of dorsal approach as it provides good exposure, less healing problems and good exposure of deep metatarsal transverse ligament. Moreover, there was a significant delay in full-weight bearing for the plantar incision and increased risk of wound healing problems [3]. Another study demonstrating the efficacy of plantar approach claiming a complication rate of 4 to 36% for plantar approach compared to 2 to 34% for dorsal approach [6]. Another group of researchers claim that equal satisfactory results can be obtained from either a plantar or dorsal approach and choice should be left for surgeon experience and personal preference [7]. Similarly, some surgeons prefer using a planter approach for recurrent disease, as surgery can be complicated by scar tissue if the neuroma is approached through the site of a previous incision [8].

In our case series, the predominant affected population were females with a mean age of 58 years. Again, this finding matches with already established research, as women in the middle ages are prone to disease with an average age of 50 years and female-to-male ratio of 4:1[3].

However, the literature supports the disease predominance in the third metatarsal space; in our study, although 57% of patients had the disease in the said space but 43% patient demonstrated Morton’s neuroma in 2nd intermetatarsal space. As per existing evidence, the presence of disease in 3rd intermetatarsal and second metatarsal space is 66% and 21% respectively [3]. In one study, however, they were able to report equal incidence of disease in 2nd and 3rd intermetatarsal space [5].

In this series, we offered conservative treatment in every case before moving towards surgery. Five out of 14 patients accepted the offer and went for ultrasound guided injection and one opted the option of blind injection in the foot by clinician. Although, some support the use of ultrasound guided injection, other prefer identification of pain spot in the clinic and infiltration of local anesthetic and steroid at the most tender point claiming favorable/comparable results with blind injection [1].  

In our case series, the results of conservative management using local anesthetic and steroid were disappointing with a mean relief of just 1.22 ± months and all patients ultimately opted to go for surgery.

This finding is very much coherent with existing evidence as all patients managed conservatively for Morton’s neuroma ultimately opted for surgery as long-term results are usually disappointing [2]. Based on our experience, we don’t recommend the use of steroid and local anesthetic as a definitive treatment of choice for Morton’s neuroma unless the patient is deemed unfit for surgery. Despite the evolution of less invasive modalities and development in radiological techniques, most of the existing literature still favors surgery as a definitive treatment of this disease [4].

Our set of patients diagnosis is supported by tissue diagnosis of neuroma in 13/14 (92%) cases thus consolidating our clinical assessment. This is much higher than the reported value in one study involving the prospective analysis of Morton’s neuroma disease of the foot where they were able to prove the histological diagnosis in only 78% of operated patients [2]. Moreover, the exceptional results in terms of resolution of symptoms also points toward correct treatment regimen.

Regarding tissue diagnosis, it has been considered as a burden to the health system by some researchers. The reason extracted from the literature narrated the fact that unless there is doubt during surgery it should not be subjected to tissue diagnosis [9]. However, others always give weightage to radiological and histological diagnosis. Few consider the clinical examination as the gold standard for diagnosis [4]. However, others have questioned this technique in modern era of evidence-based medicine [3].

We recommend the support of histology, even if the clinician is sure of diagnosis. Not only does it save any future discomfort in terms of medicolegal issues, but it also excludes an important cause of forefoot pain for future treatment in case the results of surgery are disappointing. Additionally, patients can be counselled regarding the management and guarded prognosis in case of recurrent disease [2].

The modality of choice in our series was ultrasound of foot. Although MRI was requested by clinician in one case only, but it did not add any extra information or change in treatment plan for the patient. Researchers recommend use of both modalities, however, the diagnosis of asymptomatic neuroma is high, especially with ultrasound and it is reported as 54% in some literature. Thus, clinical findings should be correlated with radiological evidence [2]. MRI has sensitivity and specificity of 93% and 68% respectively compared to ultrasound which has sensitivity and specificity of 90% and 88% respectively [3].

In our opinion, long term follow-up is vital for this disease, as in our experience initially satisfied patients may complain of return of symptoms after a mean interval of three months with complaint of pain of similar nature that was experienced before the surgery. 

In our experience, we would recommend reconsidering the diagnosis if it is not proven by radiological work up as it may be one of the factors that can lead to poor outcome after surgery. Although evidence regarding this recommendation is weak in existing literature [2]. Surgical excision of Morton’s neuroma can give excellent outcome after surgery provided patients are chosen wisely.

References

  1. Lizano-díez X, Ginés-cespedosa A, Alentorn-geli E, et al. Corticosteroid Injection for the Treatment of Morton’s Neuroma: A Prospective, Double-Blinded, Randomized, Placebo-Controlled Trial. Foot Ankle Int. 2017;38(9):944-951.
  2. Bucknall V, Rutherford D, Macdonald D, Shalaby H, Mckinley J, Breusch SJ. Outcomes following excision of Morton’s interdigital neuroma: a prospective study. Bone Joint J. 2016;98-B(10):1376-1381.
  3. Di caprio F, Meringolo R, Shehab eddine M, Ponziani L. Morton’s interdigital neuroma of the foot: A literature review. Foot Ankle Surg. 2018;24(2):92-98.
  4. Reichert P, Zimmer K, Witkowski J, Wnukiewicz W, Kuliński S, Gosk J. Long-Term Results of Neurectomy Through a Dorsal Approach in the Treatment of Morton’s Neuroma. Adv Clin Exp Med. 2016;25(2):295-302.: .
  5. Adams WR. Morton’s neuroma. Clin Podiatr Med Surg. 2010;27(4):535-45.
  6. Nery C, Raduan F, Del buono A, Asaumi ID, Maffulli N. Plantar Approach for a Morton’s Neuroma: Surgical Technique. JBJS Essent Surg Tech. 2012;2(3):e14.
  7. Habashy A, Sumarriva G, Treuting RJ. Neurectomy Outcomes in Patients With Morton’s Neuroma: Comparison of Plantar vs Dorsal Approaches. Ochsner J. 2016;16(4):471-474.
  8. Richardson DR, Dean EM. The recurrent Morton’s neuroma: what now?. Foot Ankle Clin. 2014;19(3):437-49.
  9. Mallina RK, Al-dadah K, Patel K, Ramesh P. Is Histopathological Analysis of Interdigital Morton’s Neuroma Necessary?. Foot Ankle Spec. 2017;10(6):520-523.

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Pulsed Radiofrequency Combined with Continuous Radiofrequency Ablation for the Treatment of Morton’s Neuroma: A Case Report

Posted on March 1, 2013 | Comments Off on Pulsed Radiofrequency Combined with Continuous Radiofrequency Ablation for the Treatment of Morton’s Neuroma: A Case Report

by Jackson Cohen, MD1emailsm , Sergio Lenchig, MD2emailsmpdflrg

The Foot and Ankle Online Journal 6 (3): 1

Morton’s neuroma is a benign enlargement of the third common branch of the medial plantar nerve resulting in a compression neuropathy. First line treatments usually involve shoe modification, non-steroidal anti-inflammatory medications, stretching, and local corticosteroid injections. If these measures fail, many patients will undergo surgical excision for pain relief. Recently, continuous radiofrequency (CRF) ablation has been used as an alternative to surgery; however, this is the first documented case that describes the use of pulsed radiofrequency (PRF) ablation combined with CRF for the treatment of Morton’s neuroma. A patient with two Morton’s neuromas, located in the second and third webspace of the right foot, was selected. Conservative management was attempted with no improvement before radiofrequency ablation was performed. The second and third web spaces were treated with PRF at 42 degrees for 120 seconds followed by CRF at 90 degrees for 25 to 30 seconds. Following the procedure, the patient’s pain score decreased 100% and her quality of life improved significantly as she was able to enjoy dancing in high-heeled shoes once again. There were no complications after the procedure and the patient reported no pain at the six-month follow up visit. Although surgical excision has been the standard of care for treating Morton’s neuromas when conservative measures fail, PRF combined with CRF ablation may be an effective treatment for relieving pain secondary to this condition.

Key Words: Morton’s Neuroma, Radiofrequency Ablation, Pulsed Radiofrequency, Non-surgical treatment, Foot pain

Accepted: February, 2013
Published: March, 2013

ISSN 1941-6806
doi: 10.3827/faoj.2013.0603.001

Address correspondence to: Fort Lauderdale Pain Medicine, 1930 NE 47th Street Suite 300 Fort Lauderdale, FL 33308. sergiolenchig@yahoo.com

1Resident, Department of Rehabilitation Medicine at the University of Miami Miller School of Medicine, Miami, FL. jcohen2@med.miami.edu
2Voluntary Instructor, Department of Anesthesiology, Division of Pain Medicine at the University of Miami Miller School of Medicine, Miami, Florida. Private practice, Fort Lauderdale Pain Medicine, 1930 NE 47th Street Suite 300 Fort Lauderdale, FL 33308. sergiolenchig@yahoo.com

Morton’s neuroma is a common medical condition of the foot characterized by pain between the toes. It was first identified by Civinini in 1835[1] but later named after Morton who illustrated the pathology in greater detail in 1876.[2]

More recently, it has been described as a benign enlargement of the third common branch of the medial plantar nerve, frequently located between the third and fourth metatarsal heads.[3] This plantar digital nerve usually courses under the transverse intermetatarsal ligament so enlargement of the nerve results in a compression neuropathy.[4] 80% of Morton’s neuromas are seen in women and they are usually diagnosed between the fourth and fifth decades of life.[5,6]

Patients often experience burning pain and parasthesias of their forefoot which are aggravated by walking, especially in high-heeled shoes.[7] First line treatments usually involve shoe modification, non-steroidal anti-inflammatory medications, stretching, and injections with corticosteroids and local anesthetics.[8] Repeated corticosteroid injections into the tight webspaces of the foot should be performed cautiously since it may lead to plantar fat pad atrophy[9] and eventually avascular necrosis. Another non-operative treatment that has been shown to have a high success rate in patients with Morton’s neuromas is alcohol neurolysis under ultrasound guidance.[10] Even though these conservative measures are frequently effective; many patients who do not obtain significant pain relief will elect to undergo surgical excision.

Surgical neurectomy has been established as a viable treatment option with good outcomes for many patients with Morton’s neuromas.[7,11,12] In a long term follow up study performed by Coughlin et al., 85% of the patients who underwent surgical excision were satisfied with the results from the surgery and 65% were pain-free 6 years later.[13] Another study demonstrated that 82% of patients reported excellent or good postoperative results, but 71% still had restrictions with footwear.[14]

Recently, continuous radiofrequency (CRF) ablation has been used as a less invasive method for the treatment of Morton’s neuroma before considering surgical resection. CRF utilizes the electricity generated from a radiofrequency wave to disrupt soft tissue molecules, resulting in frictional heating. When the temperature rises to a certain point, normally higher than 70 degrees Celsius, instant tissue coagulation and cell death occur resulting in destruction of neural tissue.[15] In one retrospective study, 83% of patients with Morton’s neuromas who underwent CRF expressed complete relief of symptoms after one month.[3] Additionally, in a longer term study, 87% of patients who underwent CRF had good results with a 70% reduction in the number of patients progressing to surgery.[8]

Pulsed radiofrequency (PRF) ablation is another type of radiofrequency applied intermittently at lower temperatures as compared to the continuous high heat seen in CRF. A higher voltage is used in PRF that produces a brief rise in temperature followed by elimination of heat at timed intervals. The mean tip temperature remains below the neurodestructive range, which preserves the structural integrity of the nerve16; but it still has ablative effects due to the temperature spikes and/or electrical field.[17,18] PRF may minimize the risk of nerve damage while still providing good clinical outcomes; however, there is limited data supporting this.[19]

By combining PRF with CRF, a shorter duration of CRF can be utilized thus decreasing nerve and tissue damage, while still achieving pain relief through the combined ablative effects. Based on a pubmed/medline search, this is the first documented case that describes the use of pulsed radiofrequency ablation combined with continuous radiofrequency ablation for the treatment of Morton’s neuroma.

Case Report

A 53 year-old woman with a past medical history of asthma presented to an outpatient pain clinic complaining of right foot pain for the past 5 years. The pain was located on the plantar aspect of her forefoot between the third webspace and to a lesser degree between the second webspace. The patient described the pain as sharp, stabbing, throbbing, and tingling in nature. The pain was intermittent, exacerbated with walking and dancing, especially if wearing high-heeled shoes. On a numeric pain scale, her pain reached 10 out of 10 at its maximum and decreased to 0 out of 10 with rest; however, the pain was constant with ambulation. She wore supportive sandals in addition to taking ibuprofen and naproxen over the past few years, but these medications did not provide significant pain relief.

RADMNFig1

Figure 1 Magnetic resonance imaging of the right foot. Dashed arrow indicates Morton’s neuroma located in the third webspace.

The patient was sent for a magnetic resonance imaging (MRI) of her right foot which revealed a prominent third webspace neuroma and a smaller second webspace neuroma with the confirmed diagnosis of two Morton’s neuromas. (Fig. 1) Corticosteroid with local anesthetic was then injected into each neuroma with no improvement in pain. Subsequently, alcohol neurolysis was attempted with some symptomatic relief, but its effects only lasted for one month. The patient was then referred to our pain clinic after receiving each of these treatments.

On physical exam, her right foot did not have any scars, erythema or swelling. There was severe tenderness to palpation over the third webspace, tenderness over the second webspace, and diffuse tenderness when squeezing all of the toes together. No motor or sensory deficits of the right foot were noted and distal pulses were palpable.

As described above, conservative treatment with oral pain medications, shoe modification, local steroid injections, and alcohol neurolysis were all unsuccessful in relieving her pain. Thus, the decision was made to perform PRF combined with CRF ablation for the treatment of her condition as an alternative choice to performing an open neurectomy for removal of the neuroma.

Fig 2

Figure 2 Fluoroscopy of right foot. Needle placed in the third webspace.

Informed consent for radiofrequency ablation of the second and third medial digital branches of the plantar nerve was obtained and the patient was taken to the operating room. She was placed in the prone position and her right foot was prepped with ChloraPrep® and draped with sterile technique. No sedation was used for this procedure. The first needle entry point was identified with the use of a marker needle and fluoroscopy in the AP and lateral views. (Fig. 2) Then, 2ml of 1% lidocaine was infiltrated in the third webspace followed by insertion of a 20-gauge 3-inch radiofrequency ablation needle in the transverse direction.

Fig 3

Figure 3 Fluoroscopy of right foot. Needle placed in the second webspace.

The needle was inserted to the point of initiation of the metatarsophalangeal joint. Sensory stimulation was positive and motor stimulation was negative at this point. Next, 0.5ml of Marcaine® was injected then PRF ablation at 42 degrees Celsius for 120 seconds was performed followed by CRF ablation at 90 degrees for 30 more seconds. This was repeated two more times advancing the needle 1cm each time. For the second webspace, the needle was inserted in the same fashion to the point of initiation of the metatarsophalangeal joint with sensory stimulation positive and motor stimulation negative. Placement of the needle was confirmed with fluoroscopy in the anterior posterior and lateral views. (Fig. 3) Again, 0.5ml of Marcaine® was injected into the webspace then PRF ablation at 42 degrees Celsius for 120 seconds was performed followed by CRF ablation at 90 degrees for 25 more seconds. The patient felt pain at this point so the procedure was aborted and the needles were resected.

Otherwise, the patient tolerated the procedure well with no complications. When the patient returned to the clinic one month later, she reported 100% reduction in pain with no complaints related to the procedure. She was able wear regular shoes and enjoys dancing in high-heeled shoes once again. At the 6 month follow up visit, the patient still reported no pain and was very satisfied with the procedure.

Discussion

As described in this case, PRF combined with CRF for the treatment of Morton’s neuroma is able to provide excellent pain relief while minimizing the neurodestructive effects of CRF. The two prior studies involving CRF for the treatment of this condition utilized longer exposure times of 90 seconds during the procedure thus causing more tissue damage.[3,8] A higher degree of surrounding tissue damage has been shown to be directly related to the rise in temperature and duration of CRF.[20,21] By using PRF prior to CRF, we were able to decrease the exposure time to 30 seconds of CRF, which minimized the amount of destruction to the nervous tissue while still being effective in relieving the pain. In another study, Li et al. demonstrated that when PRF was combined with CRF compared to CRF alone for the treatment of trigeminal neuralgia, there was a decrease in side effects secondary to CRF while the efficacy was preserved.[22]

One of the main benefits of PRF over CRF is that it does not require high temperatures so thermal destruction of nervous tissue does not occur. It has been proposed that PRF produces a very weak magnetic field without any significant biologic effects; however, the active tip of the radiofrequency needle produces an electric field with a very high current density (2 x 104 A/m2).[23] This electric field can induce charges on tissue and distort charged molecular structures, thus disrupting cell function without substantial elevations in temperature.[24] PRF alone has been successful in treating a number of peripheral neuropathies including sural, ilioinguinal, genitofemoral, and suprascapular.[25-27]

Despite these encouraging results, we opted to use PRF combined with CRF for our case of Morton’s neuroma as opposed to only using PRF. By using both types of radiofrequency ablation, we were able to employ each of their different ablative mechanisms[15,17,18] to achieve significant pain relief while minimizing the thermodestructive effects of CRF. Also, as CRF has been documented to be an effective treatment for this condition[3,8], we thought it beneficial to utilize this type of ablation while at the same time using PRF to shorten the duration.

Definitive treatment for Morton’s neuroma has traditionally been a surgical resection via an open neurectomy once conservative measures fail. However, as with many other medical conditions, minimally invasive procedures are becoming more accepted as an alternative prior to surgery. Additionally, many patients are seeking non-surgical treatments in order to avoid the risks associated with open surgeries. Radiofrequency ablation does not require any anesthesia, has minimal recovery time, minute scarring, and less risk of bleeding and infection as compared to larger incisions needed for surgical resection of Morton’s neuromas. Regardless of which type of radiofrequency is performed, the risk of developing complications such as deep space abscesses, hematomas, or stump neuromas as observed by Coughlin, et al., is less than in open neurectomies.[13] Moreover, the potential benefits of complete pain relief after radiofrequency ablation, as seen in this case, make it a practical choice to attempt before considering surgical intervention.

Despite the advantages of using PRF combined with CRF ablation for the treatment of Morton’s neuroma, there are some risks and limitations to this minimally invasive procedure that should be recognized. Correct placement of the needle tip is not only essential to achieving maximal ablative effects on the nervous tissue, but it is also important to avoid injury to non-targeted surrounding tissue. Unintentional thermal destruction by way of CRF can lead to permanent tissue damage in unwanted areas. The use of fluoroscopy to confirm correct placement of the needle may help avoid such complications.

Also, some patients are either not able to remain still during the ablation or tolerate the procedure secondary to pain which may shorten the anticipated duration, thus limiting the efficacy of the treatment. However, our patient achieved 100% pain relief even though the CRF ablation of the second webspace was terminated five seconds early due to pain.

In this particular case, there were no complications during or after the procedure and the patient was extremely pleased with her complete reduction in pain at the 6 month follow up visit. We will continue to use PRF combined with CRF ablation for the treatment of Morton’s neuroma when conservative management fails; however, larger studies with long-term follow up are still needed to confirm the clinical feasibility of this procedure.

Conclusion

Radiofrequency ablation is a minimally invasive procedure that can be used to treat patients with Morton’s neuromas who have failed conservative management. The findings from this case report suggest that PRF combined with CRF is a viable treatment for this condition with certain advantages over CRF alone. This procedure should be considered prior to surgical intervention due to its low risk and potential for complete pain relief; nonetheless, more studies are needed to confirm this.

References

  1. Pisani, G. Sindrome di Givinini-Morton (IIInervodigitalecommune). Tattoo di Chirugia de Piede, ed 2, Edizioni Minnerva Medica, Turin, 1993 505–510.
  2. Morton TG.  The classic. A peculiar and painful affection of the fourth metatarso-phalangeal articulation. Clin Orthop Relat Res. 1979 142: 4-9. [Pubmed]
  3. Moore JL, Rosen R, Cohen J, Rosen B. Radiofrequency thermoneurolysis for the treatment of Morton’s neuroma. J Foot Ankle Surg 2012 51: 20-22. [Pubmed]
  4. Bourke G, Owen J, Machet D. Histological comparison of the third interdigital nerve in patients with Morton’s metatarsalgia and control patients. Aust N Z J Surg. 1994 64: 421-424. [Pubmed]
  5. Bartolomei FJ, Wertheimer SJ. Intermetatarsal neuromas: distribution and etiologic factors. J Foot Surg 1983 22: 279-282. [Pubmed]
  6. Bennett GL, Graham CE, Mauldin DM. Morton’s interdigital neuroma: a comprehensive treatment protocol. Foot Ankle Int 1995 16:760-763. [Pubmed]
  7. Mann RA, Reynolds JC. Interdigital neuroma–a critical clinical analysis. Foot Ankle 1983 3: 238-243. [Pubmed]
  8. Genon MP, Chin TY, Bedi HS, Blackney MC. Radio-frequency ablation for the treatment of Morton’s neuroma. ANZ J Surg 2010 80: 583-585. [Pubmed]
  9. Basadonna PT, Rucco V, Gasparini D, Onorato A. Plantar fat pad atrophy after corticosteroid injection for an interdigital neuroma: a case report. Am J Phys Med Rehabil. 1999 78: 283-285. [Pubmed]
  10. Hughes RJ, Ali K, Jones H, Kendall S, Connell DA. Treatment of Morton’s neuroma with alcohol injection under sonographic guidance: follow-up of 101 cases. AJR Am J Roentgenol 2007 188:1535-1539. [Pubmed]
  11. Valente M, Crucil M, Alecci V. Operative treatment of interdigital Morton’s neuroma. Chir Organi Mov 2008 92: 39-43. [Pubmed]
  12. Monacelli G, Cascioli I, Prezzemolo G, Spagnoli A, Irace S. Surgical treatment of Morton’s neuroma: our experience and literature review. Clin Ter 2008 159: 165-167. [Pubmed]
  13. Coughlin MJ, Pinsonneault T. Operative treatment of interdigital neuroma. A long-term follow-up study. JBJS 2001 83A(9):1321-1328. [Pubmed]
  14. Pace A, Scammell B, Dhar S. The outcome of Morton’s neurectomy in the treatment of metatarsalgia. Int Orthop 2010 34:511-515. [Pubmed]
  15. Ni Y, Mulier S, Miao Y, Michel L, Marchal G. A review of the general aspects of radiofrequency ablation. Abdom Imaging  2005 30: 381-400. [Pubmed]
  16. Podhajsky RJ, Sekiguchi Y, Kikuchi S, Myers RR. The histologic effects of pulsed and continuous radiofrequency lesions at 42 degrees C to rat dorsal root ganglion and sciatic nerve. Spine (Phila Pa 1976) 2005 30:1008-1013. [Pubmed]
  17. Cahana A, Vutskits L, Muller D. Acute differential modulation of synaptic transmission and cell survival during exposure to pulsed and continuous radiofrequency energy. J Pain 2003 4: 197-202. [Pubmed]
  18. Erdine S, Yucel A, Cimen A, Aydin S, Sav A, Bilir A. Effects of pulsed versus conventional radiofrequency current on rabbit dorsal root ganglion morphology. Eur J Pain 2005 9:251-256. [Pubmed]
  19. Lindner R, Sluijter ME, Schleinzer W. Pulsed radiofrequency treatment of the lumbar medial branch for facet pain: a retrospective analysis. Pain Med 2006 7:435-439. [Pubmed]
  20. Chang IA, Nguyen UD. Thermal modeling of lesion growth with radiofrequency ablation devices. Biomed Eng Online 2004 Aug 6: 27. [Pubmed]
  21. Chang IA. Considerations for thermal injury analysis for RF ablation devices. Open Biomed Eng J 2010 4: 3-12. [Pubmed]
  22. Li X, Ni J, Yang L, Wu B, He M, Zhang X, Ma L, Sun H. A prospective study of Gasserian ganglion pulsed radiofrequency combined with continuous radiofrequency for the treatment of trigeminal neuralgia. J Clin Neurosci 2012 19: 824-828. [Pubmed]
  23. Sluijter M, Cosman E, Rittman W. The effects of pulsed radiofrequency fields applied to the dorsal root ganglion – A preliminary report. The Pain Clinic 1998 11:109-117.
  24. Cosman ER Jr, Cosman ER Sr. Electric and thermal field effects in tissue around radiofrequency electrodes. Pain Med 2005 6:405-424. [Pubmed]
  25. Todorov L. Pulsed radiofrequency of the sural nerve for the treatment of chronic ankle pain. Pain Physician 2011 14: 301-304. [Pubmed]
  26. Cohen SP, Foster A. Pulsed radiofrequency as a treatment for groin pain and orchialgia. Urology 2003 61:645. [Pubmed]
  27. Luleci N, Ozdemir U, Dere K, Toman H, Luleci E, Irban A. Evaluation of patients’ response to pulsed radiofrequency treatment applied to the suprascapular nerve in patients with chronic shoulder pain. J Back Musc Rehabil 2011 24:189-194. [Pubmed]

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Dextrose Prolotherapy Treatment for Unresolved “Morton’s Neuroma” Pain

Posted on June 1, 2012 | Comments Off on Dextrose Prolotherapy Treatment for Unresolved “Morton’s Neuroma” Pain

by Ross A. Hauser, MD1, Wayne A. Feister2, DO, Debra K. Brinker, RN3

The Foot and Ankle Online Journal 5 (6): 1

This study investigates the effectiveness of Dextrose Prolotherapy injections on a group of patients with “Morton’s neuroma.” These patients had failed previous conservative therapies, including surgical and non-surgical procedures as well as steroid injections. In this study, seventeen patients with neuroma pain were treated for six months. Every month, 10 to 20 injections containing 0.5 to 1 milliliter of Dextrose solution were given based on patient response. Pre- and post-treatment surveys utilized both objective data (i.e., solutions used, length and number of treatments, etc.) and subjective data (post-treatment visual analog scale or VAS ratings of pain relief/reduction). The results of this short-term study suggest that Prolotherapy, using injections of Dextrose into weakened ligaments, tendons, and joints, is a promising option among current treatment choices. Prolotherapy works by stimulating the body to repair these soft tissues. Future studies must confirm not only the efficacy but also the reduced risks of Dextrose Prolotherapy for one of the most common foot ailments.

Key words: Morton’s neuroma, neuralgia, metatarsalgia, paresthesias, intermetatarsal bursitis, inflammatory arthritis, osteomyelitis, rheumatoid arthritis, localized vasculitis, ischemia, tarsal tunnel syndrome, peripheral neuritis, synovitis, tendonitis, avascular necrosis, metatarsophalangeal joint capsulitis, Hackett-Hemwall Dextrose Prolotherapy

Accepted: March, 2012
Published: June, 2012

ISSN 1941-6806
doi: 10.3827/faoj.2012.0506.0001

Morton’s neuroma (MN) is a painful condition that affects the ball of the foot. First described in the 1800s, this affliction continues to be a common cause of forefoot pain [1]. Seemingly benign, MN pain can cause extreme discomfort, making it difficult to walk. Those affected become so cautious that they are afraid to place the afflicted foot (or feet) on the ground to take a step.

The word “neuroma” suggests a tumor of the nerve; however, the term is actually a misnomer since the condition is not necessarily an abnormal growth of the nerve [2, 3]. Also, the term neuroma does not describe what is seen with a microscope. Over time, other terms have been used to describe aspects of this pathology. Based on the shape, size, and structure (morphology) of tissues noted under the microscope, other terms may apply: perineural fibrosis, endoneural edema, neurofibromata, angioneurofibromata, local demyelination, and local vascular degeneration [4, 5] (Fig. 1).

Figure 1 Possible tissue pathologies that explain interdigital pain.

What circumstances give rise to the onset of neuromas in the foot? Chronic irritation, trauma, or excessive motion induces a severe, intermittent pain between a pair of the five metatarsal heads in the bones of the fore foot. MN pain may then radiate through the nerves to the tip of the toes [6]. The shooting pain follows a path from that web space to the touching halves of adjacent toes. Seen most commonly in the second and third web space—any interdigital space between toes can be affected [7-9] (Fig. 2).

Figure 2 Interdigital spaces.

Typical symptoms in the region of the intermetatarsal spaces include sharp pains, burning sensations, and paresthesias (abnormal sensation) with weight-bearing activity. (Fig. 3) In fact, the sensation is often described as walking with a stone in the shoe or on a folded or creased sock. As the condition progresses, the pain becomes debilitating; and walking becomes more apprehensive, even to an observer. Noting these typical symptoms, an accurate diagnosis can then be made after a thorough review of the patient’s history and a physical assessment.

Figure 3 Inflamed interdigital nerve.

Evidence on the frequency of this condition is minimal; however, a foot clinic computed the incidence of patients diagnosed with a “neuroma” at a rate of 9.3% of 4000 patients who complained of foot pain [10-12]. Although neuromas in both feet and multiple neuromas in one foot occur, both conditions are rare [13, 14]. Furthermore, neuromas are seen among patients of all ages; even so, they are more prevalent in middle-aged adults [15-17]. The condition most often affects women who frequently wear pointed, high-heeled, close-toed, ill-fitting shoes poorly designed for foot mechanics [18]. Footwear that transfers body weight to the metatarsal heads may be the reason women suffer from MN more frequently than men at a documented rate of eighteen to one [19]. The pain generally intensifies with walking, weight-bearing movement, and tight-fitting shoes.

The discomfort, however, eases with rest and the removal or change of footwear [20, 21] At the onset of the condition, additional relief may be gained by removing the shoe, massaging the foot, and wiggling the toes.

The etiology (cause) of Morton’s neuroma is controversial. A longstanding entrapment theory maintains that the third digital nerve, which is large and formed by a branch of the medial and lateral plantar nerves, is compromised by mechanical irritation. With dorsiflexion—when the toes or foot are bent upward toward the nose—the unyielding transverse ligament fixates the proximal end of the digital nerve [22, 23] (Fig. 4). However, this pinching does not always occur in one nerve; other intermetatarsal spaces can be affected [24]. Since it is not a true neuroma (tumorous nerve), some refer to the condition as Morton’s metatarsalgia [25]. Metatarsalgia is pain related to the metatarsal bones of the foot [26]. Another explanation for the pain is an ischemia or lack of blood flow through the plantar digital artery, which precedes a fibrous thickening around the nerve, called a perineural fibrosis [27]. In addition, a pathophysiological theory for MN claims that the intermetatarsal bursa—distally located to the transverse metatarsal ligament and close to the neurovascular bundles—is irritated. Thus inflamed, secondary fibrosis in the bursa can lead to the symptoms of neuroma. Lateral compression of the foot will then invariably cause pain, probably due to the inflamed bursa—not the nerve—being squeezed between the metatarsal heads [28] (Fig. 4).

Figure 4 Cross sectional view of the fore foot displaying the interdigital points of irritation/inflammation.

The inflamed and enlarged bursa causes a click when the metatarsals are squeezed. This distinctive click, called “Mulder sign,” can be used when diagnosing Morton’s neuroma [29].

A clear knowledge of conditions that affect the metatarsal region is critical to making a definitive diagnosis. Initially, possible diagnoses include metatarsal stress fracture, intermetatarsal bursitis, inflammatory arthritis, osteomyelitis, rheumatoid arthritis, localized vasculitis, ischemia, tarsal tunnel syndrome, peripheral neuritis, synovitis, tendonitis, avascular necrosis, metatarsophalangeal joint capsulitis, and others [30-32] (Fig. 5).

Figure 5 Diagnoses to consider when interdigital pain is the main symptom.

Many treatments have been developed for relief of the symptoms of Morton’s neuroma, but initially, non-surgical approaches are preferred. Among these conservative treatments from simple to complex are changing the footwear; avoiding high-heeled shoes; resting the feet; applying ice; elevating the foot; taking anti-inflammatory medications; taping and strapping, padding, and immobilizing the foot; receiving physical therapy; wearing orthotics or other shoe gear; and injecting steroids. When conservative approaches are unsuccessful, surgery is generally sought as the next step. Surgical approaches include resection, transection, decompression, excision of the involved nerve, and cryogenic nerve ablation.

Another conservative treatment for Morton’s neuroma pain is Prolotherapy, which has a longstanding record of success with hypermobility, when joints are unusually loose or abnormally flexible.

If the goal of padding and strapping is to reduce forefoot motion and pain, it is reasonable to utilize a treatment, such as Prolotherapy, that not only reduces hypermobility, but also results in joint stabilization [33].

Additionally, recent studies demonstrate that injection therapy, utilizing 4% sclerosing alcohol, has success rates of 84 – 89% [34-36]. Dextrose Prolotherapy injections will induce a proliferative response without the risk of alcohol infiltrating the surrounding tissue. The overall purpose of this study was to record the outcomes of Dextrose Prolotherapy on a group of patients with Morton’s neuroma in a private pain clinic.

Patients and Methods

In the study, an attending physician treated seventeen patients with Morton’s neuroma at a private medical clinic. All subjects signed a consent form, stating that a minimum of three and a maximum of six monthly treatments might be needed.

To meet the criteria for inclusion in the study, patients had to be at least 18-years-old, to have suffered unresolved Morton’s neuroma at any intermetatarsal space, and to have failed previous conservative treatment.

At the clinic, a search of electronic medical records (EMR) to find patients with the diagnosis of Morton’s neuroma was conducted.

To be included in the study, two criteria were paramount: 1) a diagnosis of Morton’s neuroma, which had to be the primary condition, and 2) a six-month time lapse, since the patient’s last Prolotherapy injections. The search revealed 31 patients diagnosed with Morton’s neuroma; of these, five could not be contacted by phone (three attempts were made before discontinuing phone calls). Two patients chose not to participate.

Five patients were excluded because of multiple foot problems that took priority over Morton’s neuroma: previous surgeries, osteoarthritis, and ankle problems. Two patients were excluded because not enough time had elapsed—at least six months—since their last Prolotherapy session.

Patients selected for the study had to complete preliminary oral, written, and visual surveys. Demographic information was obtained. Then the patient completed a visual analog scale (VAS), which includes ratings of pain at rest; pain with normal activities; pain while walking barefoot; ability to walk distances without pain; as well as stiffness and numbness/burning (Fig. 6). Finally, an assessment interview with clinical staff members collected both subjective and objective data, such as the type and duration of symptoms, previous treatments and tests, limitations to activity, and previous medical opinion.

Figure 6 Questionnaire used by patients to assess levels of pain.

Next, a physical examination determined objective data by checking for the following: the precise location of the pathology or point of maximal tenderness by palpating (light and/or deep touch) the affected web space; the presence or absence of Mulder’s click; and the severe pain that results with lateral compression of the forefoot.

The end of the Prolotherapy treatment was determined when patients indicated a zero to 1 on the pain scale, or their personal goals for pain relief or for the ability to function were met. Although some had little pain, their main goal was to eradicate numbness, which they found disturbing. Some patients wanted to achieve a zero to 1 level of pain while walking, even with level 4 pain while jumping. Therefore, they would stop treatment with a low level of walking discomfort.

Following treatment, interviews and surveys were completed on a monthly basis. Monthly data collection included the total percentage of improvement; VAS score of pain; level of pain intensity; level of stiffness; degree of crepitation (grating sensations from a joint); range of motion; ability to perform the ADLs (activities of daily living) and to exercise the affected body part.

Six months after the last visit, patients were called to obtain information and answered detailed questions. Interviews provided data on the level of foot/toe pain (VAS scale), percent of overall improvement, limitations/improvements in activities and walking, duration of post-treatment pain relief, and assessment of the treatment by the patient.

For data analysis, patient responses were collected, calculated, and compared at three different times: prior to Prolotherapy, during monthly visits, and in phone interviews conducted six months after Prolotherapy. Statistical analysis using Graph Pad Software calculated the paired student t-test before and after Prolotherapy.

Technique

The Hackett-Hemwall technique of Prolotherapy (www.hacketthemwall.org) was used. Each patient received 10 – 20 injections of 15% Dextrose, 0.2% Procaine, and a 10% Sarapin solution, for a total of 10 to 20 cubic centimeters of solution per foot. Each injection consisted of 0.5 to 1 cubic centimeter of solution and used a two-inch, 27-gauge needle. Injected areas were web spaces one through four—with attention given to metatarsophalangeal joints, dorsal and plantar surfaces, and joint capsules and ligaments (Fig. 7). If applicable, patients were advised to reduce or discontinue non-steroidal anti-inflammatory (NSAID), steroidal and narcotic medications, and other therapies. Prolotherapy treatments were discontinued, once a patient reached a clinical resolution of symptoms.

Figure 7 Prolotherapist injecting the third interdigital space with sclerosant solution.

Results

The final study group included 17 patients but 19 feet, since some patients suffered from MN in both feet. Ten right feet and nine left feet were treated. The average age of the 17 patients was 57 years: eleven were women, and six were men.

Before introducing Prolotherapy, study patients reported previous treatments. No one used pain medications for their symptoms. Some patients had tried wide-toed shoes, orthotics, padding, chiropractics, acupuncture, and steroid injections. Some patients had had MRI and radiographic diagnosis. One of seventeen had seen a podiatrist. A physician told three patients that surgery was required, but only one had surgery to remedy the pain on the other foot.

From patient questionnaires, averages were determined for periods of time. The average length of time patients experienced the pain of Morton’s neuroma was 20 months before entering the clinic. Patients received an average of 3.7 Prolotherapy treatments.

The average time of follow-up was 13.3 months. To determine the efficacy of treatments, only those patients with follow-up more than 6 months were included.

Patients’ subjective experience of pain offers the best measure for statistical accuracy. Patients were asked to rate their pain levels on a scale of 0 to 10—with 0 being no pain and 10 being severe crippling pain. All 17 patients reported pain as a symptom. Thus, patients were asked to report pain levels before and after Prolotherapy in these four categories: 1) pain at rest; 2) pain with normal activities; 3) pain with exercise, and 4) pain while walking barefoot.

Concerning 1) pain at rest: prior to Prolotherapy treatment, VAS pain levels averaged 4.68. None of the patients had a starting pain of less than three. After Prolotherapy treatment, VAS pain levels averaged 0.95.

Concerning 2) pain with normal activity and mobility: prior to Prolotherapy treatment, 15 of the 17 participants reported walking with some degree of pain, and a VAS pain level of 6.89. Eleven of 17 patients were unable to walk fifty feet without pain; 14 of 17 could not walk a half-mile without pain. Four of 17 patients reported an inability to walk barefoot. After Prolotherapy, all patients reported improvements in walking without pain, and a VAS pain level of 1.89. Fourteen of the 17 participants walked normally again and rated their pain relief at greater than 74%. Sixteen of the 17 could walk one block or more.

Concerning 3) pain with exercise: prior to Prolotherapy, 15 of the 17 patients reported decreased ability to exercise, and a VAS pain level of 7.27. Of those 15, eight were totally compromised and unable to exercise; five were moderately (only 30 to 60 minutes possible) to severely compromised (only 0 to 30 minutes possible). Nearly half of the patients were totally compromised in their athletic abilities prior to treatment. After Prolotherapy, 5 of the 17 patients reported being able to exercise as much as they wanted without impediments and with satisfaction, with a VAS pain level of 1.73. Other physical improvements occurred, notably, decreases in stiffness and numbness (burning). Thirteen to 14 patients reported a 100% improvement in the activities of daily living that continued to the end of the study. None reported an inability to exercise.

Concerning 4) pain while walking in bare feet: prior to Prolotherapy treatment, 10 of 17 patients could not walk barefooted without severe pain at levels eight, nine, or ten, and an average VAS pain level of 6.47. Furthermore, 12 of 17 patients could walk less than 50 feet before they experienced noticeable pain, with or without shoes. Only 3 of the 17 patients could walk more than a half-mile without pain.

After Prolotherapy, all patients had a pain level of four or less walking barefooted, and a VAS pain level of 1.65. As for walking distances without pain, all patients could walk at least one block or more. One patient was restricted to walking between 50 feet and one block. Among the 19 treated feet of the 17 patients in the study, eighteen feet could manage walking a half-mile or more, eight of the treated feet reported no walking restrictions.

When comparing the four previous categories before and after Prolotherapy, all reached a statistically significant outcome with a paired student t-test of p = <0.0001. This p-value confirms that the numerical results, when compared and tallied, exceed the mathematical probability of mere chance.

Thus, this prospective, non-controlled study demonstrates that Hackett-Hemwall Dextrose Prolotherapy decreases pain and improves the quality of life for patients with Morton’s neuroma, which was unresolved by previous therapies, medications, and interventions. Prolotherapy provided a relief of 74% for 14 out of 17 of the patients. Among the three patients who were told they needed surgery, two patients felt sufficient pain relief with Prolotherapy to avoid surgery. After the study period, patients experienced overall improvement in range of motion, ability to walk and exercise, as well as relief of stiffness and numbness/burning (Fig. 8).

Figure 8 Survey responses before and after Prolotherapy on levels of pain with various activities.

Discussion

This study should not be compared to a clinical trial in which a treatment is studied under controlled conditions. Instead, the projected goal was to document the responses of patients with unresolved Morton’s neuroma pain to the Hackett-Hemwall technique of Dextrose Prolotherapy. Clearly, the study’s strength was the number of quality of life parameters examined. Quality of life conditions—such as the ability to walk and exercise, enhanced range of motion, reduced stiffness, enjoyment of activities of daily life, and reduced levels of pain—are all important factors affecting the person with Morton’s neuroma.

Improvements in a large number of variables were most likely the result of Prolotherapy treatment. There is no medical test to quantify pain relief. However, observable, documented changes—such as the ability to walk or walk barefoot, to exercise, to work, and to use less pain therapies—are valid measures of success for patients whose health and vitality have considerably improved.

This study noted two empirical shortcomings. One is the subjective nature of the data gathered by the most reliable methods available. Surveys, for instance, relied on the patients to rate their pain, stiffness, and degree of disability. A second obvious weakness is the small number of patients involved in the study. However, on the positive side, this small study group made it possible to see results in a relatively short time span.

Many treatments for the relief of Morton’s neuroma symptoms have developed over time. Although conservative, non-surgical, and surgical approaches have been used, their effectiveness as a treatment is variable, often leaving patients with mixed results and questionable improvement.

A review of three trials that involved 121 people was not able to determine the effectiveness of conservative, surgical, and non-surgical interventions because, as the authors noted, there was insufficient evidence and research flaws. For instance, there were only three randomized controlled studies of the various treatments. The authors were also unable to find any studies to identify the incidence or prevalence of this condition. In the review of the three trials, researchers found no evidence to support the use of pronation insoles, which are routinely used as a conservative approach. Furthermore, they found no evidence supporting the effectiveness of corticosteroids (non-surgical); and they gave a poor grade to the surgical approach due to high risks of amputation neuroma (minimum of 20%), painful plantar scars, and postoperative complications [37].

Histomorphological findings are accepted as the gold standard for diagnosing Morton’s neuroma. Of consequence is a histomorphologic study of 23 nerve biopsies from patients with typical Morton’s neuroma symptoms compared to 25 plantar nerve autopsies of individuals with no record of forefoot problems. The study revealed that nerve biopsies from MN patients had the same characteristics as those removed from autopsies. Tissue samples were identical and could not be distinguished one from the other. However, none of the excised tissue in this study was found to be normal; all had the pathological features of fibrotic tissue (thickened, scarred) [38]. Another study found identical histology when comparing Morton’s neuroma and control patients, observing the same fibrotic changes in the symptomatic patients as in the asymptomatic patients [39] From this research , the question arises as to whether the “neuroma” is actually the cause of the condition, caused by other conditions, or present in normal plantar nerves?

Searches with magnetic resonance imaging (MRI) for typical pathologies of Morton’s neuroma did not discover any diagnostic features (symptomatology). In a retrospective study of 85 foot MRI examinations, 33% of patients with no clinical evidence of Morton’s neuroma showed diagnostic “lesions” suggestive of the condition [40] In a study of 70 asymptomatic volunteers, 30% were diagnosed with Morton’s neuromas [41].

In MR imaging after neuroma resection, a neuroma was found in 26% of the asymptomatic and 50% in the symptomatic web spaces [42]. Thus, MRI reveals neuroma-like abnormalities in both symptomatic and asymptomatic patients [43].

Another retrospective study of steroid injections showed a 47% improvement in the recipients [44]. A study gauging symptom relief from a series of corticosteroid injections reported that 30% of the patients attested to total symptom relief [45]. In another study involving 60 patients, the results of conservative treatment were considered poor in 73% of the cases; thus, the authors recommended surgery as the initial treatment of choice [46].

Surgical removal of the neuroma is reported to provide satisfactory relief in 76 – 85% of the patients [47, 48]. Nonetheless, there were exceptions. In a study of 56 patients with excised neuromas, two thirds of the satisfied patients continued to have tenderness at the cut end of the common digital nerve; 75% were still limited in their choice of footwear; and 14% failed to demonstrate any notable improvement. Those who did not respond to surgery continued their pre-surgical use of steroids, lidocaine, and broad-toed shoes [49]. Other complications of surgery include numbness of the affected toes, postoperative infection, tenderness at the incision, keratosis (scarring) of the sole of the foot, recurrence of pain, and an amputation neuroma. Nearly 20% of the patients continued to feel pain after the first surgery, and few found pain relief with additional surgery [50]. In view of these findings, patients should be informed of the possible results of surgery, since adverse outcomes are common.

Patients searching for alternatives to the mainstream medical care are prudent to consider Prolotherapy for reasons of which practitioners of Prolotherapy are aware. First, Prolotherapists know that ligaments need to be tighter, shorter, and stronger. If the intermetatarsal ligament is weak and loose, however, the interdigital nerve rises up between the metatarsal heads where they can be compressed and, thereby, traumatized [51]. Abnormal metatarsal mobility that results from such weakened ligaments inflames the bursa (cushioning sac) between the heads, creating a space into which tissue from the plantar side of the foot can enter and is subsequently pinched by the metatarsal heads [52]. A fibrous build-up can occur when the weak ligaments allow tissue between bones to be rubbed and irritated. Because Prolotherapy strengthens weakened ligaments and connective tissues, it is a viable treatment option.

For Prolotherapists, Morton’s “neuroma” is most likely mechanically-induced from excessive motion between the metatarsals, combined with excessive weight-bearing stress on the forefoot [53]. Hypermobility of the forefoot predisposes a person to this condition, and Prolotherapy injections at the plantar and dorsal structures of the affected metatarsals will benefit the patient [54].

Prolotherapy has a long history of being utilized for unresolved foot and toe pain [55]. In a study of 19 patients with unresolved foot and toe pain, 63% of patients noted 75% pain relief from Prolotherapy [56] In a study undertaken precisely to evaluate the effectiveness of Dextrose Prolotherapy on Morton’s neuroma pain, 16 of the 20 patients with chronic plantar fasciitis who had failed previous conservative treatment reported good to excellent results from the Prolotherapy [57].

As a treatment, Prolotherapy has been utilized for approximately 100 years, with its modern injection protocols being formalized by George S. Hackett, MD in the 1950s [58, 59]. Increasingly popular in the US, Prolotherapy is used nationally and internationally in both alternative (integrative) and allopathic (orthodox) medical practice [60] The treatment is simple. When therapeutic solutions are injected into painful and tender ligaments, tendons, and joints—an inflammation develops, which causes healing cells to proliferate and strengthen damaged ligament, tendon, and joint structures [61], These injections improve both joint stability and biomechanics, ultimately decreasing pain [62]. In this way, Prolotherapy is a safe and practical option for hypermobile joints of the foot that cause persistent pain [63].

Conclusion

While the exact cause of Morton’s neuroma (MN) is still debated, this study confirms that the Hackett-Hemwall technique of Dextrose Prolotherapy not only reduces levels of pain for patients with MN, but also enhances other quality of life concerns. Conventional therapies, on the other hand—rest, weight loss, exercises for muscle strengthening, orthotics, massage therapy, physiotherapy, manipulation, analgesics, non-steroidal anti-inflammatory drugs, anti-depressant medications, trigger point and steroid injections, and various surgical treatments—often result in residual pain for the patients [64-66]. Patients with MN, therefore, are searching for alternative treatments to relieve the pain [67]. Patients unable to find relief with traditional treatments are also hesitant to use options like surgery.

Surgery for Morton’s neuroma, for instance, presents these significant risks: numbness of the affected toe, postoperative infection, incisional soreness, scarring, and recurring stump neuromas [68, 69]. Instead of these traditional options, patients dealing with Morton’s neuroma are now trying Prolotherapy [70]

As a promising option, Prolotherapy—using injections of an irritant—tightens, shortens, and strengthens ligaments, tendons, and joints. Prolotherapy works by stimulating the body to repair these soft tissues. The solution starts and accelerates healing through inflammation, triggering a healing cascade of effects. Initially, fibroblasts—immature cells capable of producing collagen fibers—proliferate. Hence, the term Prolotherapy arose from this observable process. Once collagen forms, it is woven (reticulated) into ligament and tendon tissue. In this manner, Prolotherapy has the potential to stop the disease process.

In some cases, preliminary, anecdotal evidence suggests that Prolotherapy can reverse Morton’s neuroma. In one double-blind animal study over a six-week period, for instance, Prolotherapy was shown to increase ligament mass by 44%, ligament thickness by 27%, and ligament-bone attachment by 28% [71]. In human studies on Prolotherapy, biopsies performed after the completion of Prolotherapy showed significant increases in collagen fiber and ligament diameter of 60% [72, 73]. These finding are especially significant since a potential cause of Morton’s neuroma is weakened ligaments [74, 75].

In this prospective study, the Hackett-Hemwall technique of Dextrose Prolotherapy used on patients averaging 1.5 years of unresolved pain with Morton’s neuroma was shown to improve their quality of life, which continued 13.3 months after their last session. The 17 patients treated with Prolotherapy reported significantly less pain, stiffness, disability, or use of other pain therapies, as well as improvements in walking, range of motion, ability to exercise, and performing activities of daily living.

Patients told that there were no other treatments for pain or that surgery was their only option achieved the same positive results. This study justifies the desirability and use of Prolotherapy for Morton’s neuroma pain. Future studies need to further substantiate these findings, especially if Prolotherapy enables Morton’s neuroma sufferers to avoid surgery and its possible adverse effects. Although a study with more patients in a controlled empirical setting is needed to document the efficacy of Hackett-Hemwall Dextrose Prolotherapy, this treatment should be considered, based on the substantial advantages and minimal drawbacks (e.g., aversion to needles), as well as the reduced risks and increased rewards of Prolotherapy over conventional treatments.

References

  1. Morris MA. Morton’s metatarsalgia.clinical orthopaedics and related research. 1977 127: 203-207. [PubMed]
  2. Spina R, et al. The effects of functional fascial taping on Morton’s neuroma: A case report. Australasian Chiropractic July 2002 10: 45-50. [Website]
  3. Hassouna H, Singh D. Morton’s metatarsalgia: pathogenesis, aetiology and current management. Acta Orthop Belg 2005 71: 646-655. [PubMed]
  4. Rout R, Tedd H, Lloyd R, Ostlere S, Lavis GJ, Cooke PH, Sharp RJ. Morton’s neuroma: diagnostic accuracy, effect on treatment time and costs of direct referral to ultrasound by primary care physicians. Pual Prim Care 2009 17: 277-282. [PubMed]
  5. Morscher E. Ulrich J, Dick W. Morton’s intermetatarsal neuroma: morphology and histological substrate. Foot Ankle Int 2000 21: 558-562. [PubMed]
  6. Decherchi P. Thomas George Morton’s metatarsalgia. Presse Med 2007 36: 1098-1103. [PubMed]
  7. Pastides P, El-Sallakh S, Charalambides C. Morton’s neuroma: A clinical versus radiological diagnosis. Foot Ankle Surg. 2012 18 :22-4. [PubMed]
  8. Beltran LS, Bencardino J, Ghazikhanian V, Beltran J. Entrapment neuropathies III; lower limb. Semin Musculoskelet Radiol 2010 14: 501-111. [PubMed]
  9. Nissen Kl. Plantar digital neuritis: Morton’s metatarsalgia. JBJS 1948 30: 84-93. [PubMed]
  10. Pace A, Scammell B, Dhar S. The outcome of Morton’s neurectomy in the treatment of metatarsalgia. Int Orthop. 2010 April; 34:511-5. [PubMed]
  11. Hassouna H, Singh D. Morton’s metatarsalgia: pathogenesis, aetiology and current management. Acta Orthop Belg 2005 71: 646-655. [PDF]
  12. Banks A, et al. McGlamry’s comprehensive textbook of foot and ankle surgery. Vol 2.Philadelphia,PA. Lippincott, Williams, and Wilkins 2001.
  13. Lee KT, Lee YK, Young KW, Kim HJ, Park SY. Results of operative treatment of double Morton’s neuroma in the same foot. 2009, J Orthop Sci 2009 14: 574-578. [PubMed]
  14. Kay D, Bennett GL. Morton’s neuroma. Foot Ankle Clin. 2003 Mar;8(1):49-59. [PubMed]
  15. Thomas JL, Blitch EL 4th, Chaney DM, Dinucci KA, Eickmeier K, Rubin LG, Stapp MD, Vanore JV. Diagnosis and treatment of forefoot disorders. Morton’s intermetatarsal neuroma. J Foot & Ankle Surgery 2009 48: 251-256. [PubMed]
  16. Adams WR 2nd. Morton’s neuroma. Clin Podiatr Med Surg. 2010 27: 535-545. [PubMed]
  17. MollicaMB. Morton’s neuroma: Getting patients back on track. Physician Sportsmedicine 1997 25: 76-82. [PubMed]
  18. Wu KK. Morton neuroma and metatarsalgia. Current Opinion Rheumatology 2000 12: 131-142.[PubMed]
  19. Terk M, Kwong PK, Suthar M, Horvath BC, Colletti PM. Morton neuroma: Evaluation with MR imaging performed with contrast enhancement and fat Suppression Radiology 1993 189:239-241. [PubMed]
  20. Clinical Practice Guideline Forefoot Disorders Panel, Thomas JL, Blitch EL 4th, Chaney DM, Dinucci KA, Eickmeier K, Rubin LG, Stapp MD, Vanore JV. Diagnosis and treatment of forefoot disorders. Morton’s intermetatarsal neuroma. J Foot & Ankle Surgery 2009 4: 251-256. [PubMed]
  21. Coady CM, Gow N, Stanish W. Foot problems in middle-aged patients: keeping active people up to speed. Phys Sportsmed 1998  26: 31-42. [PubMed]
  22. Lee KS. Musculoskeletal ultrasound: how to evaluate for Morton’s neuroma. AJR Am J Roentgenol. 2009 Sep; 193(3):W172. [PubMed]
  23. Fabie F, Accadbled F, Tricoire JL, Puget J. Anatomic danger of percutaneous section of the inter-metatarsal ligament for the treatment of Morton’s neuroma. Rev Chir Orthop Reparatrice Appar Mot 2007 93: 720-724.French. [Pubmed]
  24. Bossley CJ, Cairney PC. The intermetatarsophalangeal bursa – its significance in Morton’s metatarsalgia. JBJS 980 62B: 184-187. [PubMed]
  25. Schuh R, Trnka HJ. Metatarsalgia: distal metatarsal osteotomies Foot Ankle Clin. 2011 16: 583-595. [PubMed]
  26. Birbilis T, Theodoropoulou E, Koulalis D. Forefoot complaints-the Morton’s metatarsalgia. The role of MR imaging. Acta Medica (Hradec Kralove) 2007 50: 221-222. [PubMed]
  27. Nissen Kl. Plantar digital neuritis: Morton’s metatarsalgia. JBJS 1948 30: 84-93. [PubMed]
  28. Claustre J, Bonnel F, Constans JP, Simon L. The intercapital metatarsal space: anatomical and pathological aspects. Rev Rhum Mal Osteoartic 1983 50: 435-440. [PubMed]
  29. Mendicino SS, Rockett MS. Morton’s neuroma. Update on diagnosis and imaging. Clin Podiatr Med Surg 1997 14: 303-311. [PubMed]
  30. Schreiber K, Khodaee M, Poddar S, TweedEM. Clinical Inquiry. What is the best way to treat Morton’s neuroma? 2011 60: 157-158. [PubMed]
  31. Lee M, Kim S, Huh YM, Song HT, Lee SA, Lee JW, Suh JS. Morton neuroma: Evaluated with ultrasonography and MR imaging. Korean J Radiolog 2007 8: 148-155. [PubMed]
  32. Summers A. Diagnosis and treatment of Morton’s neuroma. Emerg Nurse  2010 18: 16-17. [PubMed]
  33. Hackett GS, Henderson DG. Joint stabilization: An experimental, histologic study with comments on the clinical application in ligament proliferation. Amer J Surg 1955 89: 968-973. [PubMed]
  34. Hughes R; Ali K; Jones H; Kendal S; Connell D. Treatment of  Morton’s neuroma with alcohol injection under sonographic guidance: Follow-up of 101 cases. Am J Roentgenology 2007 188:1535-1539.[PubMed]
  35. Hyer C, Mehl LR, Block AJ, Vancourt RB. Treatment of recalcitrant intermetatarsal neuroma with 4% sclerosing alcohol injection: A pilot study. J Foot & Ankle Surgery 2005 44: 287-291. [PubMed]
  36. Dockery GL. The treatment of intermetatarsal neuromas with 4% alcohol sclerosing injections. Journal of Foot and Ankle Surgery 1999 38:403-408. [PubMed]
  37. Thomas CE, et al. Interventions for the treatment of Morton’s neuroma (review). The Cochrane Library 2005 Issue 2:1-14.
  38. Morscher  E, Ulrich J, Dick W. Morton’s intermetatarsal neuroma: Morphology and histological substrate. Foot Ankle Int 2000 21: 558-562. [PubMed]
  39. Bourke G, Owen J, Machet D. Histological comparison of the third interdigital nerve in patients with Morton’s metatarsalgia and control patients. Aust NZ J Surg 64: 421-424. [PubMed]
  40. Bencardino J, Rosenberg ZS, Beltran J, Liu X, Marty-Delfaut E. Morton’s neuroma: Is it always symptomatic? Am J Roentgenology 2000 175: 649-653. [PubMed]
  41. Zanetti M, Strehle JK, Zollinger H, Hodler J. Morton neuroma and fluid in the intermetatarsal bursae on MR images of 70 asymptomatic volunteers. Radiology 1997 203: 516-120. [PubMed]
  42. Espinosa N, Schmitt JW, Saupe N, Maquieira GJ, Bode B, Vienne P, Zanetti M. Morton neuroma: MR imaging after resection—postoperative MR and histologic findings in asymptomatic and symptomatic intermetatarsal spaces. Radiology 2010 255: 850-856. [PubMed]
  43. Resch S, Stenstrom A, Jonsson A, Jonsson K.  The diagnostic efficacy of magnetic resonance imaging and ultrasonography in Morton’s neuroma: a radiological-surgical correlation. Foot Ankle Int 1994 15: 88-92. [PubMed]
  44. Bennett GL, Graham CE, Mauldin DM. Morton’s interdigital neuroma: A comprehensive treatment protocol. Foot Ankle Int 1995 16: 760-763. [PubMed]
  45. GreenfieldJ,  Rea J Jr, Ilfeld FW. Morton’s interdigital neuroma: Indications for treatment by local injections versus surgery. Clinical Orthopaedics Rel Research 1984 185:142-144. [PubMed]
  46. Gaynor R, Hake D, Spinner SM, Tomczak RL. A comparative analysis of conservative versus surgical treatment of Morton’s neuroma JAPMA  1989 79: 27-30. [PubMed]
  47. Monacelli G, Cascioli I, Prezzemolo G, Spagnoli A, Irace S. Surgical treatment of Morton’s neuroma: our experience and literature review. Clin Ter 2008 159: 165-167. Article in Italian. [PubMed]
  48. Faraj A, Hosur A.  The outcomes after using two different approaches for excision of Morton’s neuroma. Chinese Medical Journal 2010 123: 2195-2198. [PubMed]
  49. Mann R, Reynolds JC. Interdigital neuroma-a critical clinical analysis. Foot & Ankle 1983 3: 238-243. [PubMed]
  50. Johnson J, Johnson KA, Unni KK. Persistent pain after excision of an interdigital neuroma – results of reoperation. JBJS 1988 70A: 651-657. [PubMed]
  51. Read JW, Noakes JB, Kerr D, Crichton KJ, Slater HK, Bonar F. Morton’s metatarsalgia: sonographic findings and correlated histopathology. Foot Ankle Int. 1999  2093:153-161. [PubMed]
  52. Mulder JD. The causative mechanism in Morton’s metatarsalgia. JBJS 1951 33B: 94-95. [PubMed]
  53. Wu KK. Morton interdigital neuroma: A clinical review of it etiology, treatment and results. J of Foot and Ankle Surgery 1996 35(2): 112-119; discussion 187-8. [PubMed]
  54. Hackett G, et al. Ligament and tendon relaxation treated by prolotherapy. 5th ed.Oak Park,IL. Gustav A. Hemwall 1992
  55. Hauser R, et al. Prolo your pain away! 3rd edition.Oak Park,IL.BeulahLand Press 2007 139-147.
  56. Hauser R,  A retrospective observational study on Hackett-Hemwall dextrose prolotherapy for unresolved foot and toe pain at an outpatient charity clinical in rural Illinois. J of Prolotherapy 2011 3: 543-551. [Website]
  57. Ryan M. Sonographically guided intratendinous injections of hyperosmolar dextrose/lidocaine: A pilot study for the treatment of chronic plantar fasciitis. Brit J Sports Medicine 2009 43: 303-306.  [Website]
  58. Hauser RA. Punishing the pain. Treating chronic pain with Prolotherapy. Rehab Manag 1999 12: 26-28. [PubMed]
  59. Rabago D. Prolotherapy in primary care practice. Primary Care 2010 37: 65-80. [PubMed]
  60. Schnirring L. Are your patients asking about prolotherapy? Physician Sportsmedicine 2000 28:15-17.
  61. Rabago D, Best TM, Beamsley M, Patterson J. A systematic review of prolotherapy for chronic musculoskeletal pain. Clin J Sports Medicine 2005 15: 376-380. [PubMed]
  62. Centeno CJ, Elliott J, Elkins WL, Freeman M. Fluoroscopically guided cervical prolotherapy for instability with blinded pre and post radiographic reading. Pain Physician 2005 8: 67-72.  [PubMed]
  63. Tsatsos G. Prolotherapy in the treatment of foot problems. JAPMA 2002  92: 366-368. [PubMed]
  64. Martin E. Pharmacologic management of foot pain in the older patient. J Am Podiatr Med Assoc 2004 94(2):98-103.
  65. Drury AL. Use of homeopathic injection therapy in treatment of Morton’s neuroma. Altern Ther Health Med. 2011 17:48. [PubMed]
  66. Jannink M. Effectiveness of custom-made orthopaedic shoes in the reduction of foot pain and pressure in patients with degenerative disorders of the foot. Foot Ankle Int 2006 27: 974-979. [PubMed]
  67. Kay D, Bennett GL. Morton’s neuroma Foot Ankle Clin. 2003  8: 49-59. [PubMed]
  68. Singh SK, Loli JP, Chiodo CP. The surgical treatment of Morton’s neuroma. Current Orthopaedics 2005: 19 379-384.
  69. Hughes R; Ali K; Jones H; Kendal S; Connell D. Treatment of Morton’s neuroma with alcohol injection under sonographic guidance: Follow-up of 101 cases. American Journal of Roentgenology 2007 188: 1535-1539. [PubMed]
  70. Hauser, RA, Hauser, MA. Prolo Your Pain Away!, 2007 3rd edition Beulah Land Press,Oak ParkIL pg 144-145.
  71. Liu Y. An in situ study of the influence of a sclerosing solution in rabbit medial collateral ligaments and its junction strength. Connective Tissue Research1983 2: 95-102. [PubMed]
  72. Maynard JA, Pedrini VA, Pedrini-Mille A, Romanus B, Ohlerking F. Morphological and biochemical effects of sodium morrhuate on tendons. J  Orthopaedic Research. 1985 3: 236-248.  [PubMed]
  73. Hauser R, et al. Prolo your pain away! 3rd edition.Oak Park,IL.BeulahLand Press 2007 139-147.
  74. Wu KK. Morton’s interdigital neuroma: a clinical review of its etiology, treatment and results. J Foot Ankle Surg 1996 35:187-188. [PubMed]
  75. Hauser RA, Hauser MA, Cukla JK. A retrospective observational study on Hackett-Hemwall Dextrose Prolotherapy for unresolved foot and toe pain at an outpatient charity clinic in rural Illinois. J Prolotherapy. 2011 3: 543-551.  [Website]
  76. Ravin T, Cantieri M, Pasquarello G. Principles of Prolotherapy. Denver,CO:AmericanAcademy of Musculoskeletal Medicine; 2008.

Address Correspondence to: : Ross Hauser, MD, Caring Medical, 715 Lake St., Suite 600, Oak Park, IL 60301

1Medical Director, Caring Medical & Rehabilitation Services; Editor-in-Chief, Journal of Prolotherapy
2Private Practice, Medical Editor, Ohio University Clinical Assistant Professor, Bowling Green State University Adjunct Assistant Professor
3Registered Nurse, Caring Medical & Rehabilitation Services

© The Foot and Ankle Online Journal, 2012

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