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Mortons Neuroma

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Other Names

  • Morton's Neuroma
  • Morton neuralgia
  • Morton metatarsalgia
  • Interdigital neuroma
  • Intermetatarsal neuroma

Background

  • This page refers to fibrosis of the digital nerves of the toes, commonly referred to as Morton's Neuroma (MN)

History

  • First described in the literature in 1876 by an American surgeon, Thomas George Morton. (need citation)
  • Note, Civinini and Durlacher preceded Morton in describing the condition in 1835 and 1845, respectively[1]

Epidemiology

  • There are no solid epidemiologic studies on MN, no descriptions of prevalence or incidence
  • It is known to most commonly affect middle ages women (need citation)

Pathophysiology

  • General
    • Fibrosis of the digital nerves due to pressure or repetitive irritation leading to fibrosis
    • Location is most commonly the 3rd intermetatarsal space
    • Degenerate tissue therefore causes localized pain and discomfort mainly on weight bearing
  • Size
    • Not all neuromas are symptomatic
    • Bencardino et al: mean diameter 4.1 mm in asymptomatic group, 5.3 mm in symptomatic group[2]
    • Diagnosis of MN is considered relevant when diameter exceeds 5 mm and correlates to clinical findings[3]
    • Size of lesion does not always correlate with symptom severity[4]
    • Smaller lesions respond better to steroid injections than larger lesions, although all do respond

Etiology

  • General
    • Overall, not well understood
    • Generally, though to be secondary to pressure or repetitive irritation leading to thickness of the nerve
    • About 17% of patients report a history of trauma[5]
  • Transverse metatarsal ligament
    • Has been implicated by some as a compressing structure (need citation)
  • Ischemic hypothesis
    • Proposed by Giakoumis et al. based on histological evidence of digital arteries luminal occlusion[6]
  • Foot wear
    • High-heeled shoes with tight toe box could lead to Morton’s neuroma
  • During sports
    • Repetitive hyperdorsiflexion of MTPJ may pull the interdigital nerve against the transverse metatarsal ligament leading to nerve irritation[7]
    • Significant dorsiflexion during running (toe-off phase of gait cycle), ballet dance maneuvers (demi-pointe, relevé and grand plié)
    • Cross-training and racket shoes may increase forefoot workload, avoid during distance running[8]

Pathohistology

  • Findings[9]
    • Neural edema
    • Demyelination (axonal injury)
    • Perineural fibrosis

Associated Conditions


Risk Factors

  • General
    • Female > Male
  • Sports
    • Running
      • Due to the increased weight bearing through the forefoot
    • Dancing
    • Racquet
  • Orthopedic

Differential Diagnosis


Clinical Features

  • History
    • Paraesthesia within the affected digital nerve, accompanied by forefoot pain
    • 17% of patients report a history of trauma[5]
    • The pain is typically characterized as burning, tingling, numbness
    • More than 50% of the patients report altered sensation, feeling of pebble in the shoe
    • Exacerbated by walking, use of tight or heeled shoe
  • Physical Exam: Physical Exam Foot
    • There are no visual cues to the presence of a neuroma
    • Hallux Valgus may be present
    • Abnormal light touch over the dorsal or plantar foot reproducing symptoms is 25% sensitive, 100% specific (need citation)
    • A pin can be used similarly to light touch
  • Special Tests

Evaluation

Radiographs

Ultrasound

  • Sensitivity up to 95%[10]
  • Systematic review and meta-analysis by Bignotti found no difference in sensitivity between the two modalities[11]

MRI

  • Gold standard
    • Sensitivity: 87%[12]
    • Specificity: 100%
  • Optimizing view
    • Prone position MRI with foot in plantar flexion significantly enhances the visibility
  • Findings
    • Most easily seen on T1 axial cuts
    • Hypointense area on T2-weighted MRI images relative to fat

Classification

  • Not applicable

Management

Nonoperative

  • Indications
    • Vast majority of cases
  • Metatarsal Bar
    • The most common treatment
    • Made by orthotists spreads the heads of the metatarsals to relieve pressure on the neuroma
    • Require the patient to wear broad toe box shoes
  • Toe Padding
    • Can help support the metatarsal arch
    • Keeps metatarsal bones apart from each other to relieve the relatively crushed nerve in between
  • Other Orthotic
    • No evidence for use of inversion/ eversion soles
  • Footwear modification
    • Substitute poor-fitting footwear with accommodative wide toe box shoes
    • For example, avoid cross training shoes[8]
  • Activity modification
    • Avoiding activities with a potential harm to the diseased nerve
  • Corticosteroid Injection
    • Likely considered standard of care for MN
    • RCT showed CSI superior to anesthetic injection alone[13]
    • At 1 year following CSI, about 1/3 of patients require surgical excision due to recurrence of pain (need citation)
    • CSI more effective if used within one year of onset of symptoms[14]
    • Mahadevan et al found no difference between CSI by palpation or US guidance[15]
    • Santiago et al. noted benefit with US guidance over palpation guidance at 3 months but not at 6 months[16]
    • Saygi et al: CSI superior to foot wear modification at 6 and 12 months[17]
  • Ethanol/ Alcohol Injection
    • Multiple studies show improvement in patient reported outcome measures at 12 months, reduction in neuroma size[18]
    • Gurdezi et al: 84% report complete resolution of symptoms at 1 year, 29% at 5 years[19]
    • Complications include burning pain associated with alcohol injections which in some cases lasted for weeks
    • Also note, fibrosis following alcohol injection can complicate surgical approach
  • Radiofrequency Ablation
    • Several small studies have reported good patient outcomes[20][21][22]
  • Capsaicin
    • Campbell et al: small RCT found a benefit from capsaicin injection up to 4 weeks following the procedure[23]
  • Cryoablation
    • Among patients who had cryoablation, 38.7% were completely pain free and 45.2% had reduced pain[24]
  • Yttrium Aluminium Garnet (YAG) laser
    • Gimber et al found YAG laser therapy to improve US findings, symptoms in a retrospective review[25]
  • Extra Corporeal Shockwave Therapy
    • Compared to placebo, patients in the ECST group had improved AOFAS and VAS scores[26]
    • Fridman showed benefit compared to placebo up to 12 weeks[27]
  • Botox Injection
    • In a small pilot study, 70% of patients reported improvement in symptoms at 3 months[28]
  • Prevention/ Avoid
    • Footwear with high heels
    • Tapered narrow toe box
    • Cross-training firm outsole

Operative

  • Indications
    • Failure of conservative management
  • Technique
    • Surgical excision (neurectomy)

Rehab and Return to Play

Rehabilitation

  • Post-operative
    • Weight bearing can begin immediately if dorsal approach was used
    • If plantar approach, must wait for surgical wound to heal before beginning weight bearing

Return to Play/ Work


Complications and Prognosis

Prognosis

  • Nonoperative outcomes
    • Patients tend to do better with conservative measures when the disease is detected in its early stages (need citation)
  • Surgical outcomes
    • The plantar approach is less commonly used, success ranges from 51% to 85%[29]
    • The dorsal approach is more well tolerated, success ranges from 61% to 85%[29]
    • Failure rate following surgical excision has been reported as up to 30%.

Complications

  • Unable to return to sport

See Also


References

  1. Durlacher L, editor. Treatise on corns, bunions, the diseases of nails and the general management of the feet. London: Simpkin-Marshall; 1835
  2. encardino J, Rosenberg ZS, Beltran J, Liu X, Marty-Delfaut E. Morton’s neuroma. Am J Roentgenol. 2000;175(3):649e653. https://doi.org/10.2214/ ajr.175.3.1750649.
  3. 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(2). https://doi.org/10.1148/radiology.203.2.9114115.
  4. Makki D, Haddad BZ, Mahmood Z, Saleem Shahid M, Pathak S, Garnham I. Efficacy of Corticosteroid Injection Versus Size of Plantar Interdigital Neuroma Level of Evidence: II, Prospective Comparative Study. doi:10.3113/ FAI.2012.0722.
  5. 5.0 5.1 Mahadevan D, Venkatesan M, Bhatt R, Bhatia M. Diagnostic accuracy of clinical tests for morton’s neuroma compared with ultrasonography. J Foot Ankle Surg. 2015;54(4):549e553. https://doi.org/10.1053/j.jfas.2014.09.021.
  6. Giakoumis M, Ryan JD, Jani J. Histologic evaluation of intermetatarsal Morton’s neuroma. J Am Podiatr Med Assoc. 2013; 103(3):218–22.
  7. Ferkel E, Davis WH, Ellington JK. Entrapment neuropathies of the foot and ankle. Clin Sports Med. 2015;34(4):791–801
  8. 8.0 8.1 Hockenbury RT. Forefoot problems in athletes. Med Sci Sports Exerc. 1999;31(7 Suppl):S448–58.
  9. 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(6):421e424. http://www.ncbi.nlm.nih.gov/pubmed/7516653.
  10. Torres-Claramunt R, Gines A, Pidemunt G, Puig L, De Zabala S. MRI and ultrasonography in Morton’s neuroma: diagnostic accuracy and correlation. Indian J Orthop. 2012;46(3):321e325.
  11. Bignotti, Bianca, et al. "Ultrasound versus magnetic resonance imaging for Morton neuroma: systematic review and meta-analysis." European radiology 25.8 (2015): 2254-2262.
  12. Zanetti M, Ledermann T, Zollinger H, Hodler J. Efficacy of MR imaging in patients suspected of having Morton’s neuroma. AJR Am J Roentgenol. 1997;168(2):529–32.
  13. Thomson CE, Beggs I, Martin DJ, et al. Methylprednisolone injections for the treatment of morton neuroma. J Bone Jt Surg Am. 2013;95(9):790e798
  14. Markovic M, Bs M. Effectiveness of ultrasound-guided corticosteroid injection in the treatment of morton’s neuroma. Foot Ankle Int. doi:10.3113/ FAI.2008.0483.
  15. Mahadevan, D., et al. "Corticosteroid injection for Morton’s neuroma with or without ultrasound guidance: a randomised controlled trial." The Bone & Joint Journal 98.4 (2016): 498-503.
  16. Santiago FR, Mu~noz PT, Pryest P, Martínez AM, Olleta NP. Role of imaging methods in diagnosis an treatment of Morton’s neuroma. World J Radiol. 2018;10(9):91e99.
  17. Saygi, Baransel, et al. "Morton neuroma: comparative results of two conservative methods." Foot & ankle international 26.7 (2005): 556-559.
  18. Fanucci E, Masala S, Fabiano S, et al. Treatment of intermetatarsal Morton’s neuroma with alcohol injection under US guide: 10-month follow-up. Eur Radiol. 2
  19. Gurdezi S, White T, Ramesh P. Alcohol injection for morton’s neuroma: a five year follow-up. Foot Ankle Int. 2013.
  20. Chuter, Graham SJ, et al. "Ultrasound-guided radiofrequency ablation in the management of interdigital (Morton’s) neuroma." Skeletal radiology 42.1 (2013): 107-111.
  21. Moore JL, Rosen R, Cohen J, Rosen B. Radiofrequency thermoneurolysis for the treatment of morton’s neuroma. J Foot Ankle Surg. 2012;51(1):20e22
  22. Overview | Radiofrequency Ablation for Symptomatic Interdigital (Morton’s) Neuroma | Guidance | NICE.
  23. Campbell, Claudia M., et al. "A randomized, double-blind, placebo-controlled trial of injected capsaicin for pain in Morton's neuroma." Pain 157.6 (2016): 1297-1304.
  24. Caporusso, Eric F., Lawrence M. Fallat, and Ruth Savoy-Moore. "Cryogenic neuroablation for the treatment of lower extremity neuromas." The Journal of foot and ankle surgery 41.5 (2002): 286-290.
  25. Gimber, Lana H., et al. "Ultrasound evaluation of Morton neuroma before and after laser therapy." AJR Am J Roentgenol 208.2 (2017): 380-385.
  26. Seok, Hyun, et al. "Extracorporeal shockwave therapy in patients with Morton's neuroma: a randomized, placebo-controlled trial." Journal of the American Podiatric Medical Association 106.2 (2016): 93-99.
  27. Fridman, Robert, Jarrett D. Cain, and Lowell Weil Jr. "Extracorporeal shockwave therapy for interdigital neuroma: a randomized, placebo controlled, double-blind trial." Journal of the American Podiatric Medical Association 99.3 (2009): 191-193.
  28. Climent JM, Mondejar-Gomez F, Rodríguez-Ruiz C, Díaz-Llopis I, Gomez- Gallego D, Martín-Medina P. Treatment of Morton neuroma with botulinum toxin a: a pilot study. Clin Drug Invest. 2013
  29. 29.0 29.1 Bhatia, Maneesh, and Lauren Thomson. "Morton’s neuroma–current concepts review." Journal of Clinical Orthopaedics and Trauma 11.3 (2020): 406-409.2013;34(9):1198e1204
Created by:
John Kiel on 14 June 2019 08:41:56
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Last edited:
4 October 2022 13:22:35
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