Use of Vascularized Sural Nerve Grafts for Sciatic Nerve Reconstruction After Malignant Bone and Soft Tissue Tumor Resection in the Lower Legs

Immediate sciatic nerve reconstruction using an ipsilateral common peroneal nerve graft at the time of sarcoma resection

BACKGROUND

Concomitant resection of the sciatic nerve along with a malignant tumor is no longer a contraindication for limb-sparing surgery, as most of these patients remain ambulatory. However, sciatic nerve reconstruction after sarcoma resection is not commonly performed. Restoration of nerve function can improve patient quality of life. We describe our experience with four patients who underwent sciatic nerve reconstruction using an ipsilateral common peroneal nerve graft at the time of sarcoma resection.

METHODS

Because of the low chance of peroneal nerve recovery, the ipsilateral peroneal trunk was used as a graft to reconstruct the tibial trunk of the sciatic nerve. Two patients were men and two were women. Mean age was 45.3 years (range, 15-62). Mean sciatic nerve defect length was 9.4 cm (range, 8.5-12.0). Proximal thigh defects (three patients) were reconstructed with a double cable; the one patient with a distal thigh defect underwent single cable reconstruction. Mean operation time was 492 min (range, 428-682).

RESULTS

Mean length of the harvested peroneal trunks was 21 cm (range, 11-26). Mean graft length was 11.9 cm (range, 11-13). Postoperative course was uneventful in all four patients. One patient died of sarcoma lung metastasis and could not be evaluated. Three patients were followed for more than 2 years. Two patients achieved British Medical Research Council grade 4 plantar flexion; the remaining patient achieved grade 5 plantar flexion and grade 4 toe flexion. Semmes-Weinstein monofilament sensory testing showed loss of protective sensation on the plantar surface in all three. Musculoskeletal Tumor Society scores at last follow-up were 60.0%, 70.0%, and 43.3%, respectively.

CONCLUSIONS

Immediate sciatic nerve reconstruction using an ipsilateral common peroneal nerve graft avoids reconstruction delay and scar tissue formation, which is advantageous for nerve recovery. This technique may be considered when sciatic nerve resection is anticipated during sarcoma resection.

Novel Approach of Femur Shortening With Insertion of Expandable Rod to Achieve End-to-End Repair of Sciatic Nerve Laceration

BACKGROUND

Sciatic nerve injuries are challenging for diagnosis and treatment. Particularly in proximally located high-grade injuries, neurorrhaphy often has poor outcomes. Most advocate autologous grafting and some more recently have suggested the value of knee flexion braces to facilitate end-to-end repair.

OBJECTIVE

To describe a case of femur shortening to facilitate tension-free, end-to-end sciatic nerve neurorrhaphy.

METHODS

The patient was a 17-year-old man who was injured by the propeller of a motor boat and suffered a series of lacerations to both lower extremities including transection of his right sciatic nerve in the proximal thigh. After extensive mobilization of the nerve, a greater than 7-cm gap was still present. The patient was treated with femur shortening to facilitate end-to-end coaptation. He subsequently had an expandable rod placed which was lengthened 1 mm per day until his leg length was symmetric.

RESULTS

Within 7 months postoperatively, the patient had an advancing Tinel sign and paresthesias to the dorsum of his foot. Nine months postoperatively, he had early mobility in his plantarflexion.

CONCLUSION

We present a novel method of femur shortening with insertion of an expandable rod to facilitate direct end-to-end and tension-free sciatic nerve neurorrhaphy in a proximally located injury. Furthermore, larger scale and comparative studies are warranted to further explore this and other techniques.

Restoration of hamstring function following sciatic nerve resection at the greater sciatic foramen with reconstruction involving acellular nerve allograft and vascularized sural nerve autograft: A case report

Segmental loss of the sciatic nerve secondary to oncologic resection or trauma is detrimental to hamstring and leg function. The diameter of this nerve and the length of its axons spanning the lower extremity create significant challenges in reconstruction and optimizing return of sensory or motor function. The purpose of this report is to describe outcomes of a free vascularized sural nerve graft to preserve hamstring function in a large proximal sciatic nerve defect beginning at the greater sciatic foramen. A 44-year-old female underwent neoadjuvant chemotherapy and radiation for treatment of a left sciatic nerve synovial cell sarcoma. The patient underwent R0 resection of the proximal left sciatic nerve resulting in a 15 cm defect. An ipsilateral vascularized sural nerve graft was used to reconstruct the medial aspect of the sciatic nerve, prioritizing the tibial division, in an effort to restore hamstring function and plantar sensation. A 5 cm allograft nerve was added to the cutaneous branches of the sural nerve graft to better span the large defect and reconstruct the lateral aspect of the nerve. The patient's postoperative course was uneventful. At 1-year follow-up, the patient showed MRC grade 4/5 strength with knee flexion and steady gait pattern with a left ankle-foot orthosis. Outcomes support the use of a single vascularized nerve graft alongside acellular nerve allograft to restore motor function in large diameter and large defect mixed nerve injuries.

Morbidity and Function Loss After Resection of Malignant Peripheral Nerve Sheath Tumors

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas. Their resection may lead to serious morbidity. Incidence of postoperative motor and sensory deficits is unknown, and reconstruction aimed at restoring such deficits is infrequently carried out.

OBJECTIVE

To identify the incidence and risk factors of postoperative morbidity in MPNST as well as the use and outcomes of functional reconstructions in these patients.

METHODS

Postoperative function and treatment of MPNSTs diagnosed from 1988 to 2019 in 10 cancer centers was obtained. Two models were constructed evaluating factors independently associated with postoperative motor (<M3) or critical sensory loss. Critical sensation was defined as partial or complete loss of hand, foot, or buttocks sensation.

RESULTS

A total of 756 patients (33.4% neurofibromatosis type 1, NF1) were included. MPNSTs originated in 34.4% from a major nerve. Of 658 surgically treated patients, 27.2% had <M3 muscle power and 24.3% critical sensory loss. Amputations were carried out in 61 patients. Independent risk factors for motor and sensory loss included patients with NF1, symptomatic, deep-seated, extremity, or plexus tumors originating from major nerves (all P < .05). A total of 26 patients underwent functional reconstructions. The majority (64%) of these patients regained at least M3 muscle power and 33% M4 despite 86% receiving multimodal therapy.

CONCLUSION

Resection of MPNSTs commonly results in motor and sensory deficits. Patients with NF1, symptomatic, deep-seated tumors, arising from major nerves were associated with a higher risk for developing postoperative morbidity. Functional reconstructions are infrequently performed but can improve functional outcomes.

Delayed Presentation of Sciatic Nerve Injury with Gap: A Case Report with a Unique Solution from the Past

CASE

A 35-year-old farmer presented with a foot ulcer on his left flail foot because of a sciatic nerve injury of 1-year duration. A gap of 11 cm was observed in the sciatic nerve for which he underwent 2-staged pedicled peroneal nerve grafting and posterior bone block procedure for the ankle. He had S3 grade sensation at 5-year follow-up without any recurrence of ulcer and a stable foot without external support for walking.

CONCLUSION

Staged pedicled peroneal nerve grafting with a posterior bone block procedure is a viable solution for very large sciatic nerve defect with predictable results.

A systematic review of functional outcomes after nerve reconstruction in extremity soft tissue sarcomas: A need for general implementation in the armamentarium

Resection of nerves in extremity soft tissue sarcomas (STS) can lead to large functional deficits. Nerve reconstructions are rarely performed and little is known on their outcomes and indications for their use, even though they are essential in restoring sensation in limb salvage procedures. This study investigated current knowledge on functional outcomes and considerations to be taken before performing such reconstructions after sarcoma resection. A systematic search was performed in July 2018 in PubMed and Embase databases according to PRISMA guidelines. Search terms related to "soft tissue sarcoma" and "nerve reconstruction" were used. Studies evaluating functional outcomes after nerve grafting or nerve transfers in extremity STS were included. Qualitative synthesis was performed on all studies. Nineteen studies were included after full-text screening, describing 26 patients. The majority of patients had a nerve reconstruction in the upper extremity (65%). Perioperative radiotherapy was administered in 67% and perioperative chemotherapy in 29% of patients. Nerve grafting was most commonly performed (n = 23) and nerve transfers were performed in six patients. A wide variety of outcome measures were used. Most patients recovered at least some motor function and sensation, but success rates were higher after upper than lower extremity defects. Multimodal treatment did not preclude successful reconstructions. Nerve reconstructions in extremity STS allow the restoration of sensation in limb salvation, even motor nerve function can be restored with satisfactory function. The use of multimodal therapy does not seem to interfere with success. Nerve reconstructions should therefore be considered in STS patients.