Sciatic nerve reconstruction: limb preservation after sarcoma resection

A Systematic Review of the Orthoplastic Approach in Adult Lower Extremity Soft Tissue Sarcoma Flap Reconstruction

BACKGROUND

The orthoplastic approach to patient care has changed the way patients with a wide variety of lower extremity pathology are treated. Through a systematic review, we aim to analyze outcomes in adult patients with lower extremity soft tissue sarcomas who undergo an orthoplastic flap management approach to their care.

METHODS

A systematic review of adult lower extremity soft tissue sarcoma excision with plastic surgery flap reconstruction was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines searching the Pubmed, Embase, and Web of Science databases from inception to April 2023.

RESULTS

After removal of duplicates, title and abstract screening, and full-text review, 26 articles were accepted for inclusion. The total mean follow-up duration was 32.0 ± 24.3 months. Reconstruction used microvascular free flaps in 65.5% (487/743), while 34.5% (256/743) were local flaps. 85.8% (307/358) of patients ambulated postoperatively. Revision surgery was required in 21% of patients during their respective follow-up periods. The limb salvage rate was 93.4% (958/1,026). Among pooled surgical outcomes, 22.2% (225/1,012) of patients experienced a perioperative complication.

DISCUSSION

Our study demonstrates that although complication rates in lower extremity soft tissue sarcoma reconstruction may be further optimized, a multidisciplinary flap reconstructive approach provides high rates of limb salvage and functional postoperative ambulation.

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.

Do Liquid Nitrogen-treated Tumor-bearing Nerve Grafts Have the Capacity to Regenerate, and Do They Pose a Risk of Local Recurrence? A Study in Rats

BACKGROUND

Under most circumstances, the resection of soft tissue sarcomas of the extremities can be limb-sparing, function-preserving oncologic resections with adequate margins. However, en bloc resection may require resection of the major peripheral nerves, causing poor function in the extremities. Although liquid nitrogen treatment has been used to sterilize malignant bone tumors, its use in the preparation of nerve grafts has, to our knowledge, not been reported. Hence, this study aimed to investigate the tumor recurrence and function after peripheral nerve reconstruction using liquid nitrogen-treated tumor-bearing nerves in a rat model.

QUESTIONS/PURPOSES

(1) Do liquid nitrogen-treated frozen autografts have regeneration capabilities? (2) Do liquid nitrogen-treated tumor-bearing nerves cause any local recurrences in vivo in a rat model?

METHODS

Experiment 1: Twelve-week-old female Wistar rats, each weighing 250 g to 300 g, were used. A 10-mm-long section of the right sciatic nerve was excised; the prepared nerve grafts were bridge-grafted through end-to-end suturing. The rats were grouped as follows: an autograft group, which underwent placement of a resected sciatic nerve after it was sutured in the reverse orientation, and a frozen autograft group, which underwent bridging of the nerve gap using a frozen autograft. The autograft was frozen in liquid nitrogen, thawed at room temperature, and then thawed in distilled water before application. The third group was a resection group in which the nerve gap was not reconstructed. Twenty-four rats were included in each group, and six rats per group were evaluated at 4, 12, 24, and 48 weeks postoperatively. To assess nerve regeneration after reconstruction using the frozen nerve graft in the nontumor rat model, we evaluated the sciatic functional index, tibialis anterior muscle wet weight ratio, electrophysiologic parameters (amplitude and latency), muscle fiber size (determined with Masson trichrome staining), lower limb muscle volume, and immunohistochemical findings (though neurofilament staining and S100 protein produced solely and uniformly by Schwann cells associated with axons). Lower limb muscle volume was calculated via CT before surgery (0 weeks) and at 4, 8, 12, 16, 20, 24, 32, 40, and 48 weeks after surgery. Experiment 2: Ten-week-old female nude rats (F344/NJcl-rnu/rnu rats), each weighing 100 g to 150 g, were injected with HT1080 (human fibrosarcoma) cells near the bilateral sciatic nerves. Two weeks after injection, the tumor grew to a 10-mm-diameter mass involving the sciatic nerves. Subsequently, the tumor was resected with the sciatic nerves, and tumor-bearing sciatic nerves were obtained. After liquid nitrogen treatment, the frozen tumor-bearing nerve graft was trimmed to a 5-mm-long tissue and implanted into another F344/NJcl-rnu/rnu rat, in which a 5-mm-long section of the sciatic nerve was resected to create a nerve gap. Experiment 2 was performed with 12 rats; six rats were evaluated at 24 and 48 weeks postoperatively. To assess nerve regeneration and tumor recurrence after nerve reconstruction using frozen tumor-bearing nerve grafts obtained from the nude rat with human fibrosarcoma involving the sciatic nerve, the sciatic nerve's function and histologic findings were evaluated in the same way as in Experiment 1.

RESULTS

Experiment 1: The lower limb muscle volume decreased once at 4 weeks in the autograft and frozen autograft groups and gradually increased thereafter. The tibialis anterior muscle wet weight ratio, sciatic functional index, muscle fiber size, and electrophysiologic evaluation showed higher nerve regeneration potential in the autograft and frozen autograft groups than in the resection group. The median S100-positive areas (interquartile range [IQR]) in the autograft group were larger than those in the frozen autograft group at 12 weeks (0.83 [IQR 0.78 to 0.88] versus 0.57 [IQR 0.53 to 0.61], difference of medians 0.26; p = 0.04) and at 48 weeks (0.86 [IQR 0.83 to 0.99] versus 0.74 [IQR 0.69 to 0.81], difference of median 0.12; p = 0.03). Experiment 2: Lower limb muscle volume decreased at 4 weeks and gradually increased thereafter. The median muscle fiber size increased from 0.89 (IQR 0.75 to 0.90) at 24 weeks to 1.20 (IQR 1.08 to 1.34) at 48 weeks (difference of median 0.31; p< 0.01). The median amplitude increased from 0.60 (IQR 0.56 to 0.67) at 24 weeks to 0.81 (IQR 0.76 to 0.90) at 48 weeks (difference of median 0.21; p < 0.01). Despite tumor involvement and freezing treatment, tumor-bearing frozen grafts demonstrated nerve regeneration activity, with no local recurrence observed at 48 weeks postoperatively in nude rats.

CONCLUSION

Tumor-bearing frozen nerve grafts demonstrated nerve regeneration activity, and there was no tumor recurrence in rats in vivo.

CLINICAL RELEVANCE

A frozen nerve autograft has a similar regenerative potential to that of a nerve autograft. Although the findings in a rat model do not guarantee efficacy in humans, if they are substantiated by large-animal models, clinical trials will be needed to evaluate the efficacy of tumor-bearing frozen nerve grafts in humans.

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.

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.

Management of great vessels and nerves in limb-salvage surgery for bone and soft tissue tumors

In recent years, limb-salvage surgery has gradually replaced amputations and become one of the main treatment strategies for patients with bone and soft tissue tumors of the extremities. The goals of tumor resection in limb-salvage surgery are to reduce the recurrence rate and preserve as much limb function as possible. However, depending on the size and specific location of the tumor, large neurovascular bundles may be involved. In addition, management of large nerves and vessels can make wide marginal resection more difficult. Sites where these problems commonly arise include the sciatic and tibial common peroneal nerve, artery and vein in the lower limbs.

Surgical outcome of soft tissue sarcomas of the adductor compartment

PURPOSE

To review outcomes and complications of 25 consecutive patients with soft tissue sarcomas in the adductor compartment.

METHODS

Records of 11 men and 14 women aged 20 to 83 (mean, 56) years who underwent resection for soft tissue sarcomas in the adductor compartment were reviewed. Two of the patients had undergone inadequate resection of the tumour elsewhere. No patient had metastases. 20 and 2 patients underwent neo-adjuvant and postoperative radiotherapy, respectively. The interval between radiotherapy and surgery was at least 3 weeks. No neo-adjuvant chemotherapy was given. 24 patients underwent limb salvage surgery and one had external hemipelvectomy. 21 patients had direct wound closure; in 4 a microsurgical free flap was used.

RESULTS

The overall survival rate was 81% and 72% at 3 and 5 years, respectively, and remained unchanged until the end of follow-up. Four patients died from pulmonary metastases and one died from liver metastases. One patient had local recurrence, and 7 (26%) developed major complications. Five patients underwent revision surgery.

CONCLUSION

Good survival and local control rates can be achieved in patients with soft tissue sarcomas in the adductor compartment using limb salvage and radiotherapy.

Complete femoral nerve resection with soft tissue sarcoma: functional outcomes

BACKGROUND

The functional consequences of resecting the femoral nerve in conjunction with soft tissue sarcoma management are not well described. In comparison, sciatic nerve involvement by sarcoma was once considered an indication for amputation, but sciatic resection is now commonly performed as part of a limb-salvage approach. We compared functional outcomes following resection of either the femoral or sciatic nerve in patients with soft tissue sarcoma. We also compared both groups with patients with large thigh sarcomas without nerve involvement.

METHODS

The prospectively collected database from a tertiary referral center for sarcomas was retrospectively reviewed to identify all patients with resection of the femoral nerve performed during wide excision of a soft tissue sarcoma. Patient demographics, treatment, complications, and functional outcomes in the form of the Musculoskeletal Tumor Society (MSTS) 1987 score, MSTS 1993 score, and Toronto Extremity Salvage Score (TESS) were collected. Control groups of sarcoma patients with sciatic nerve resection in the thigh as well as similarly sized tumors in the quadriceps requiring no nerve resections were also analyzed.

RESULTS

Ten patients with femoral nerve resections were identified, all women, aged 47-78 years, with large soft tissue sarcomas of varied subtypes. All patients received adjuvant radiotherapy, most preoperatively. Six patients developed fractures during long-term follow-up, four in nonirradiated portions of the skeleton but directly from falls related to absent active knee extensors, and two at least partially attributable to sequelae of radiation. MSTS 1987 hip scores demonstrated one excellent, four good, and five fair results. MSTS 1993 hip scores averaged 71.4 +/- 17.2% and TESS averaged 61.7 +/- 21.8. There were no significant differences between the functional scores for patients with femoral or sciatic nerve resections (P = 1.0).

CONCLUSIONS

Femoral nerve resection appears more morbid than anticipated. The falls to which patients were prone, even years after surgery, subject them to ongoing long-term risks for fractures and other injuries. These nerve-specific functional implications should be considered when counseling patients in preparation for possible resection of the femoral nerve when it is directly involved by a soft tissue sarcoma.

Peripheral nerve considerations in the management of extremity soft tissue sarcomas

Evaluation of peripheral nerves, both clinically and with imaging, is critical in the evaluation of patients with extremity soft tissue sarcomas. If an essential peripheral nerve is felt to be adjacent to a soft tissue sarcoma but not circumferentially surrounded, it can usually be salvaged using the technique of epineural dissection in the setting of adjuvant radiation. If, however, a critical nerve is circumferentially involved with tumor, it must be sacrificed for the sake of local control. Various reconstruction techniques are available in this situation, including nerve grafting, distal nerve transfer, and tendon transfer, with each technique having specific indications. Regardless of the technique, it is important to inform the patient that normal extremity function is not likely to be achieved. The issue of nerve involvement therefore becomes a critical factor in determining the possibility of limb salvage in borderline cases. For the situation in which postoperative function is already expected to be compromised due to vascular, bone, or extensive soft tissue resection, nerve resection may be the ultimate deciding factor in recommending amputation rather than limb salvage.

Soft tissue sarcomas of the popliteal fossa: outcome and risk factors

BACKGROUND

Limb salvage surgery of popliteal soft tissue sarcomas may be hampered due to the incomplete anatomical containment of this region and the vicinity of neurovascular structures. The scope of this study was to determine outcome and to define risk factors.

PATIENTS AND METHODS

27 patients (53.3+/-15.8 y; 16/27 male) with popliteal soft tissue sarcomas were assessed. Mean follow-up was 40.9+/-33.8 months (48.5+/-36.7 months in surviving patients). 9/27 patients were included after prior treatment elsewhere (5 after intralesional resections and 4 local recurrences). The lesions were staged IB in 8/27 patients, IIB in 17/27 and III in 2/27. Immediate amputations were performed in 7/27 patients. 15/27 patients were subjected to radiation therapy (preoperative in 6/15 cases), 8/27 patients received chemotherapy (5/8 preoperatively).

RESULTS

Overall survival and disease-free survival at 5 y was 63.0% and 59.5%. Local recurrence occurred in 2 patients. 8/27 patients developed metastatic disease after 28.9+/-9.8 months. Survival (p=0.397) and disease-free survival (p=0.113) did not differ in patients after amputations vs limb salvage. Application of radiation therapy was associated with a better survival (p=0.003). Complications related to the surgical intervention were recorded in 2/27 patients, complications related to radiation therapy occurred in 6/15 patients.

DISCUSSION

Despite being extra-compartmental, popliteal sarcomas can be treated with a high rate of limb salvage while equal safety compared to amputations is maintained. Irradiation improved survival in our patient population. In cases with involvement of neurovascular structures, preoperative down-staging with radio or chemo-therapy may prevent amputation.

Sciatic neuropathy: case report and discussion of the literature on postoperative sciatic neuropathy and sciatic nerve tumors

Sciatic nerve injury and dysfunction is not an uncommon cause of lower extremity symptoms in a musculoskeletal practice. We present the case of a man who presented with lower extremity weakness, pain, and cramps, and was initially diagnosed at an outside institution with bilateral S1 radiculopathies and recommended for spine surgery. He came to us for a second opinion. Electrodiagnostic testing revealed an isolated sciatic neuropathy and the patient was referred for imaging, which showed a sciatic nerve sheath tumor. Review of the literature on sciatic neuropathies shows that there can be many possible etiologies of sciatic nerve dysfunction, but that hip arthroplasty continues to be the leading risk factor. Sciatic nerve tumors are not commonly described in the literature and their definitive management remains unclear.

Reconstruction for lower extremity limb salvage in soft tissue carcinoma

Limb salvage procedures for the lower extremity have a 95% success rate and have essentially supplanted primary amputation as the primary treatment for limb-threatening malignancies. En bloc tumor resection involving major neural and vascular structures that once led to amputation are now successfully reconstructed using free-tissue transfer in combination with neoadjuvant and adjuvant chemoradiation therapies and brachytherapy. Planning for reconstruction of complex lower extremity wounds begins at the time of diagnosis and extends to postoperative rehabilitation. Developing a successful reconstructive plan requires a team approach with accurate assessment of the anticipated loss of critical structures, wound location, defect size, and an understanding of the local and distant tissues available for reconstruction. Comprehensive assessment of the anticipated wound combined with an understanding of the distant and local tissues available for reconstruction allows the reconstructive surgeon to select tissues from the entire body that have improved functional and aesthetic outcomes for patients.