Outcomes and Complications of Neuroma Resection and Implantation into the Muscle in

Lower Extremity

1,2 Chamnanni Rungprai, M.D.

Co-authors 1Phinit Phisitkul, M.D. 1Christopher Cyclosz, M.D.

AOFAS 2015 Annual Meeting ePoster

1.University Of Iowa Hospital and Clinic, Iowa, USA 2.Phramongkutklao hospital and college of medicine, Bangkok, Thailand

NO CONFLICT TO DISCLOSE

Outcomes and Complications of Neuroma Resection and Implantation into the Muscle in

Lower Extremity

Chamnanni Rungprai, M.D.

My disclosure is in the Final AOFAS Mobile App.

I have no potential conflicts with this presentation.

Introduction Peripheral neuromas typically form on the

cutaneous nerves in response to irritation, compression, stretch, or trauma following fracture, surgery or amputation.1 The majority of post-traumatic end

neuromas remain asymptomatic and previous studies reported that up to 30% of patients becomes painful because nerve can be proliferation or true neuroma develops into an area of frequent motion or scar tissue.2,3 When neuroma occurs in a superficial

area or close proximity to joint or tendon, it can cause severe pain. Pain may be exacerbated, particularly in

the lower extremities because of weight bearing or in response to pressure from footwear and prosthesis.4,5 Conservative management is the first line

but it often unsuccessful and if these fail, surgical treatment is indicated.6

Standard treatment of neuroma is resection of the pathologic nerve proximal to the affected part. However, the consequence of simple

neurectomy, axons of the proximal nerve stump attempt to regenerate and post-traumatic end neuroma can recur.4,6

Recently, it has been suggested that implanting the proximal nerve ending into the suitable tissue bed such as, vein,7 muscle,3,8 and bone,9 can promote the formation of a smaller, more organized post-traumatic end neuroma compared to simple neurectomy.10,11

Recent evidence in upper extremities suggest that implanting of the proximal nerve ending into nearby muscle can be a safe and effective.12 However, the studies documenting the use of this procedure in the foot and ankle region are limited.

Materials and methods The primary outcomes

include Foot Function Index (FFI) Short Form-36 (SF-36)

PCS and MCS Visual Analogue Scale

Secondary outcome includes Complications

Retrospective chart review were performed evaluating 106 consecutive patients (118 neuromas) who were diagnosed with neuromas in the lower extremities and underwent neurectomy with intramuscular implantation between 2008 and 2013

Surgical technique

Figure 1: Sural nerve neuroma: A separate incision was made proximally in the calf 7-8 cm in size at approximate 15-cm below the knee joint (A). A 4-cm incision was made along the lateral aspect of foot over the previous incisional scar (B) and careful dissection until the sural nerve and its branches were identified (C). After No. 2/0 Vicryl was sutured directly to the nerve and ligated two times around the nerve, the nerve was sharply cut 2-mm distal to the suture knot, and the needle was subsequently removed (D). The distal part of sural nerve was then passed into a window created in the posterior compartment (E). The nerve was then removed entirely from the distal incision and it was sent for pathologic study (F). The nerve was passed using a Keith needle into the muscle (G) and the sutures were tied on top of the skin and were allowed to retract into the subcutaneous plane (H).

Surgical technique

Figure 2: Sciatic nerve neuroma after previous above knee amputation: A 10-cm straight incision was used on the lateral aspect of the amputated limb (A). The neuroma of the sciatic nerve was demonstrated and sent for the pathological study (B).

Table 1 Demographic characteristics of nerve resection with intramuscular implantation. Parameters

Neurectomy with implantation of proximal nerve

stump into muscle Number of patients / legs or feet / neuromas 106 / 110/ 118

Age of time at surgery (years) (range) 47.7 ± 12.5 (16-81)

Male : Female ratio (no. of patients) 10 : 56

BMI(Kg/m2) (range) 32.2 ± 8.1 (17.4-62.4)

Duration of symptom before surgery (range, months) 30.8 ± 33.7 (6-180)

Duration of follow up (months) (range, months) 17.1 ± 15.0 (6-66)

Location of neuroma (legs/neuromas)

Sciatic nerve 1/1 Common peroneal nerve 5/5 Superficial peroneal nerve 35/36 Deep peroneal nerve 1/1 Saphenous nerve 3/3 Sural nerve 20/20 Plantar nerve 5/5 Interdigital nerve (no. of patients/neuromas) 36/47

2nd intermetatarsal space 11/14 3rd intermetatarsal space 22/30 4th intermetatarsal space 3/3 Side (Left/Right) 63/47

TABLE 2 Comparison between pre- and post-operative functional outcomes in patients with neuroma resection and intramuscular implantation.

Outcomes Nerve resection with intramuscular implantation

(total=106) *Operative time (minutes) 60.3 ± 24.6

(17-128)

*Pre / Post-operative Visual Analog Scale (range) (no.)

7.8 ± 1.7 / **2.9 ± 1.9 (n=96) (p = 0.000)

*SF-36 Score: at final follow up (points) PCS: pre / post-operative (no.) 35.3 ± 9.7 / **41.4 ± 9.5

(n=57) (p = 0.000)

MCS: pre / post-operative (no.) 44.6 ± 11.6 / **51.2 ± 11.3 (n=57) (p = 0.000)

*Foot Function Index (FFI): pre / post-operative at final follow up

Pain: pre / post-operative (no.) 68.9 ± 14.5 / **37.2 ± 11.9 (n=49) (p = 0.000)

Disability: pre / post-operative (no.) 64.4 ± 15.6 / **38.3 ± 13.8 (n=49) (p=000)

Activity limitation: pre / post-operative (no.) 66.9 ± 12.7 / **48.6 ± 22.6 (n=49) (p = 0.000)

Total score: pre / post-operative (no.) 66.7 ± 11.7 / **41.4 ± 14.8 (n=49) (p = 0.000)

*Pair t-test was used to compare all pre and post-operative functional results (VAS, SF-36 (PCS and MCS), and FFI (Pain, Disability, Activity limitation, and Total score)) and it is statistically significant difference with p value less than 0.05(**).

TABLE 3 Comparisons of functional outcomes between peripheral nerve, interdigital nerve, and amputation groups.

Functional Outcomes Peripheral nerve

neuroma (n=68)

Interdigital neuroma (n=36)

Amputation neuroma (n=2)

*Pre / Post-operative Visual Analog Scale (range) (no.)

7.9 ± 1.8 / 3.0 ± 2.3 (n=59)

7.4 ± 1.4 / 1.9 ± 1.6 (n=35)

7.5 ± 2.1 / 1.5 ± 1.6

(n=2)

*SF-36 Score: at final follow up (points)

PCS: pre / post-operative (no.) 35.2 ± 9.4 / 40.7 ± 9.3

(n=22)

37.4 ± 7.5 / 45.7 ± 8.8

(n=30)

28.6 ± 2.7 / 35.0 ± 2.0

(n=2)

MCS: pre / post-operative (no.) 43.3 ± 13.0 / 50.3 ± 12.3

(n=22)

47.2 ± 9.9 / 53.8 ± 4.7

(n=30)

30.7 ± 4.3 / 37.1 ± 0.7

(n=2) ***Foot Function Index (FFI): pre / post-operative at final follow up

Pain: pre / post-operative (no.) 68.3 ± 13.1 / 37.5 ± 12.2

(n=30)

55.9 ± 17.8 / 30.3 ± 10.0

(n=25)

N/A

Disability: pre / post-operative (no.) 68.9 ± 15.3 / 37.6 ± 13.1

(n=30)

65.7 ± 17.0 / 33.6 ± 13.7

(n=25)

N/A

Activity limitation: pre / post-operative (no.)

66.1 ± 14.4 / 47.6 ± 21.5

(n=30)

74.7 ± 12.8 / 38.7 ± 20.9

(n=25)

N/A

Total score: pre / post-operative (no.) 63.5 ± 11.8 / 40.9 ± 14.1

(n=30)

65.7 ± 10.5 / 34.2 ± 12.7

(n=25)

N/A

(*) One-way ANOVA was used to compare mean improvement of VAS, SF-36, and FFI between peripheral nerve, interdigital nerve, and amputation groups and (**) significance was considered when the p-value less than 0.05. (***) Pair t-test was used to compare the difference of FFI (Pain, Disability, Activity limitation, and Total score) between peripheral nerve and interdigital nerve neuroma. (****) significance was considered when the p-value less than 0.05.

Limitations Strengths

Results and Discussion

Retrospective design, and therefore no randomization was used in the methods.

Some patients were lost to follow-up and some did not response to the questionnaires, resulting in approximately fifty percent of patients available to be analyzed at final follow-up.

Consecutive case collection.

Relatively large number of subject.

Systematically collected outcome data using validated assessment methods.

All surgeries were performed by the same group of fellowship-trained orthopaedic foot and ankle surgeons.

Neurectomy with intramuscular implantation demonstrated significant improvement of post-operative functional outcomes (FFI, SF-36, and VAS (p < 0.05 all)) compared to pre-operative period. Complications were persistent pain at the same level (6/118, 5.8%), painful scar (4/118, 3.4%), and complex regional pain syndrome (CRPS) (1/118, 0.9%) were the complications after the surgery.

Conclusion Neurectomy with intramuscular implantation demonstrated significant improvement in functional outcomes with low complication rates for patients with painful neuromas in the lower extremity.

This technique was considered safe and effective for patients suffered from this disabling and painful condition.

Reference: 1. Civinini F. Su di un gangliare rigonfiamento della pinata del plede. Mem Chir Archiespedale 1835;4. 2. Weinfeld SB, Myerson MS. Interdigital neuritis: diagnosis and treatment. J Am Acad Orthop Surg 1996;4(6):328–35. 3. Fridman, R; Cain, JD; Weil, L, Jr.: Extracorporeal shockwave therapy for interdigital neuroma: a randomized, placebo-controlled, double-blind trial. Journal of the American Podiatric Medical Association. 99: 191-193, 2009. 4. Markovic, M; Crichton, K; Read, JW; Lam, P; Slater, HK: Effectiveness of ultrasound-guided corticosteroid injection in the treatment of Morton's neuroma. Foot & ankle international. 29: 483-487, 2008. http://dx.doi.org/10.3113/fai.2008.0483 5. Peters PG, Adams SB Jr, Schon LC. Foot Ankle Clin. 2011 Jun;16(2):305-15. doi: 10.1016/j.fcl.2011.01.010. Review. PMID: 21600450 [PubMed - indexed for MEDLINE] 6. DiPreta, JA: Metatarsalgia, lesser toe deformities, and associated disorders of the forefoot. The Medical clinics of North America. 98: 233-251, 2014. http://dx.doi.org/10.1016/j.mcna.2013.10.003 7. Coughlin, MJ; Pinsonneault, T: Operative treatment of interdigital neuroma. A long-term follow-up study. The Journal of bone and joint surgery American volume. 83-A: 1321-1328, 2001. 8. Jain, S; Mannan, K: The diagnosis and management of Morton's neuroma: a literature review. Foot & ankle specialist. 6: 307-317, 2013. http://dx.doi.org/10.1177/1938640013493464 9. Wolfort, SF; Dellon, AL: Treatment of recurrent neuroma of the interdigital nerve by implantation of the proximal nerve into muscle in the arch of the foot. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons. 40: 404-410, 2001. 10. Mackinnon SE, Dellon AL, Hudson AR, Hunter DA. Plast Reconstr Surg. 1985 Sep;76(3):345-53. PMID: 4034753 [PubMed - indexed for MEDLINE] 11. Dellon, AL: Treatment of recurrent metatarsalgia by neuroma resection and muscle implantation: case report and proposed algorithm of management for Morton's "neuroma". Microsurgery. 10: 256-259, 1989.