Long-Term Donor-Site Morbidity Following Entire Sural Nerve Harvest for Grafting.

PURPOSE: The sural nerve is the autologous nerve used most commonly for grafting. However, recent studies indicate a high rate of complications and complaints after sural nerve removal. In this prospective study, we evaluated donor-site morbidity following full-length sural nerve harvesting on long-term follow-up. METHODS: Fifty-one legs from 43 patients who underwent complete sural nerve harvesting for brachial plexus reconstruction were included in the study. After an average of 5 years, with a minimum postoperative follow-up of 12 months, sensory deficits in the leg and foot were analyzed using 2.0-g monofilaments. Regions of sensory deficit were marked with a skin marker and photographed. Over these regions of decreased sensation, we tested nociception using an eyebrow tweezer. Patients were also asked about pain, cold intolerance, pruritis, difficulties walking, and foot swelling. RESULTS: Regions most affected (84% of patients) were over the calcaneus and cuboid. However, in these regions, nociception was preserved. Regions of decreased sensation extended to the calf region in 11 of 51 legs. In 13 patients, we also observed regions of decreased sensation on the proximal leg. In five feet, the sensation was entirely preserved. No patient had any complaints about pain, cold intolerance, itchiness, difficulties walking, or foot swelling. CONCLUSION: Decreased sensation with nociception preserved was most common along the lateral side of the foot over the calcaneus and cuboid. Removing the entire sural nerve produced no long-term complaints of pain. Sural nerve use appears safe. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Sural communicating nerve for application as a vascularized nerve graft: A microneurovascular anatomic study in cadavers.

INTRODUCTION: Sural nerve harvest causes paraesthesia to the lateral heel of the foot, which can debilitate those with already compromised proprioception. To circumvent this, we investigated an alternative donor nerve, branch of the lateral sural nerve complex called the sural communicating nerve (SCoNe), for its harvest and use as a vascularized nerve graft, in cadaver. METHODS: The SCoNe was visualized by dissection in 15 legs from 8 human cadavers and the relationship of the SCoNe to the overall sural nerve complex was documented. The surface markings, dimensions, and the micro-neurovascular anatomy in the super-microsurgery range (up to 0.30 mm) of the SCoNe was recorded and analyzed. RESULTS: SCoNe graft surface marking was confined within a triangle drawn between the fibular head laterally, the popliteal vertical midline medially and the tip of the lateral malleolus inferiorly. The proximal end of the SCoNe was situated at a mean intersection distance of 5 cm from both the fibular head and popliteal midline respectively. The mean length of the SCoNe was 226 ± 43 mm with a mean proximal diameter of 0.82 mm and mean distal diameter of 0.93 mm. In 53% of the cadavers, an arterial input was present in the proximal third of the SCoNe and veins were predominantly (87%) present in the distal third. In 46% and 20% of the 15 legs respectively, there was a nutrient artery and vein perfusing the SCoNe in its central segment. The external mean diameter of this artery was 0.60 ± 0.30 mm, while the vein was slightly larger with a mean diameter of 0.90 ± 0.50 mm. DISCUSSION: SCoNe graft may preserve lateral heel sensation, compared to sural nerve harvest, pending clinical studies. It may have wide applications as a vascularized nerve graft, including being ideal as a vascularized cross-facial nerve graft because its nerve diameter is similar to the distal facial nerve branches. The accompanying artery is a good anastomotic match to the superior labial artery.

The Role of the Cross Face Nerve Graft in Facial Reanimation and Endoscopic Harvest of the Sural Nerve.

Cross-face nerve grafting (CFNG) allows for spontaneous, involuntary facial movement for patients with irreversible hemifacial paralysis. This technique uses an intact contralateral facial nucleus and nerve as an input and axon source, allowing donor neural input to be routed through a nerve graft across the face. The sural nerve is well equipped for use as a nerve graft due to its length and minimal donor site morbidity. Endoscopic nerve harvest techniques allow for efficient, minimally invasive dissection that improves the integrity of the harvested nerve.

A New Standardized Clinical Model for Evaluation of Nerve Guides: A Single-Blinded Randomized Controlled Prospective Study.

BACKGROUND: Autologous nerve transplantation is the accepted clinical standard for reconstruction of peripheral nerve defects. Bioengineered nerve guides as an alternative to autologous nerve transplantation have been described in previous studies and several different types are commercially available. Examination of the implementation of these devices in the clinical setting is an important step in determining their applicability in reconstructive nerve surgery. METHODS: In a single-blinded randomized controlled prospective study, the authors examined 34 patients undergoing diagnostic nerve biopsy (2 cm). The biopsy-induced nerve gap was interposed using a segment of the lesser saphenous vein in 16 patients. Eighteen patients had no nerve reconstruction and served as a control group. A further 10 participants were included as a healthy cohort. Nerve regeneration was assessed using von Frey filaments preoperatively and 1 day and 3, 6, 9, and 12 months postoperatively. RESULTS: Patients who received defect bridging of the sural nerve with a venous graft showed better regeneration of lateral foot sensitivity than patients without venous graft. CONCLUSIONS: The distal sural nerve biopsy can be used as a baseline model to evaluate peripheral nerve regeneration. Newly developed nerve guides could be tested in other unpredictable and challenging clinical peripheral nerve lesions. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

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.

[The de-epidermized sural flap: An original technique to increase the reliability of the neurocutaneous sural flap]. / Le lambeau sural désépidermisé : technique originale de fiabilisation du lambeau neurocutané sural.

BACKGROUND: The neurocutaneous sural flap is useful to cover defects of the distal quarter of the lower limb. Nevertheless, severe complications occur in 14% of the cases, and venous congestion is reported in 75% of these cases. This congestion can lead to total necrosis of the flap and a failure of the procedure. We describe a new surgical method aiming to reduce the risk of venous congestion occurrence and failure of the defect coverage. PATIENTS AND METHODS: We realized a retrospective study of patients who undergone a de-epidermized distally based neurocutaneous sural flap in our surgery department from 2015 to 2020. The following data were collected: sex, age, vascular risk factors, size of the wound, defect area, etiology, delay between the surgery of the flap and the split-thickness skin graft and complications. RESULTS: The cohort is composed of 5 cases. We reported no failure of the coverage of the defect. There were no cases of venous congestion. CONCLUSION: The de-epidermized distally based neurocutaneous sural flap could increase the reliability of these flaps by reducing the risk of venous congestion. A larger study comparing the classic technique to the de-epidermized sural flap could confirm these data on a greater number of cases and position this technique in the therapeutic arsenal.

Donor site morbidity after sural nerve grafting: A systematic review.

BACKGROUND: Understanding the morbidity of sural nerve harvest is important when counselling patients regarding nerve grafts. Existing data consist of small studies with varying degrees of follow-up and a wide range of reported donor site outcomes. The objective of this study was to systematically review the literature and pool the current data for postoperative outcomes after sural nerve graft harvest. METHODS: A systematic review of literature was conducted to identify studies that examined donor site outcomes of sural nerve graft harvests. RESULTS: Five-hundred and fourteen studies were identified through a literature search, and nine studies met inclusion criteria. There were 240 patients who underwent sural nerve grafts. The most common methods for sensory evaluation were patient survey (44.4%) and Semmes-Weinstein evaluation (33.3%). Five studies reported surface areas of sensory loss, and this generally decreased over time after sural nerve grafting. Overall, 87.2% of patients (n = 190) reported sensory loss, 25.6% (n = 42) of patients reported pain, 22.2% (n = 28) of patients reported cold sensitivity, and 10% (n = 20) of patients reported functional impairment at follow-up. When the proximal sural nerve was spared during harvest, the extent of sensory loss and pain were less than harvest at the popliteal fossa (87.4% vs 95.7%, p = 0.0407 and 9.1% vs 35.5%, p = 0.0004, respectively). CONCLUSIONS: In this study, we present the extent of sensory loss and rates of pain, cold sensitivity, and functional impairment after sural nerve harvest. These data should be discussed prior to surgery in order for patients and surgeons to make an informed decision.

Efficacy of surgical repair for the functional restoration of injured facial nerve.

BACKGROUND: Early surgical repair to restore nerve integrity has become the most commonly practiced method for managing facial nerve injury. However, the evidence for the efficacy of surgical repair for restoring the function of facial nerves remains deficient. This study evaluated the outcomes of surgical repair for facial nerve lesions. METHODS: This retrospective observational study recruited 28 patients with the diagnosis of facial nerve injury who consecutively underwent surgical repairs from September 2012 to May 2019. All related clinical data were retrospectively analyzed according to age, sex, location of the facial nerve lesion, size of the facial nerve defect, method of repair, facial electromyogram, and blink reflex. Facial function was then stratified with the House-Brackmann grading system pre-operation and 3, 9, 15, and 21 months after surgical repair. RESULTS: The 28 patients enrolled in this study included 17 male and 11 female patients with an average age of 34.3 ± 17.4 years. Three methods were applied for the repair of an injured facial nerve, including great auricular nerve transplantation in 15 patients, sural nerve grafting in 7 patients, and hypoglossal to facial nerve anastomosis in 6 patients. Facial nerve function was significantly improved at 21 months after surgery compared with pre-operative function (P = 0.008). Following surgical repair, a correlation was found between the amplitude of motor unit potential (MUP) and facial nerve function (r = -6.078, P = 0.02). Moreover, the extent of functional restoration of the facial nerve at 21 months after surgery depended on the location of the facial nerve lesion; lesions at either the horizontal or vertical segment showed significant improvement(P = 0.008 and 0.005), while no functional restoration was found for lesions at the labyrinthine segment (P = 0.26). CONCLUSIONS: For surgical repair of facial nerve lesions, the sural nerve, great auricular nerve, and hypoglossal-facial nerve can be grafted effectively to store the function of a facial nerve, and MUP may provide an effective indicator for monitoring the recovery of the injured nerve.

Free neurosensory flap based on the accompanying vessels of lateral sural cutaneous nerve: anatomic study and preliminary clinical applications.

BACKGROUND: The posterior aspect of the leg is an ideal donor site for flap surgery. In this study, the anatomy was investigated of the lateral sural cutaneous nerve (LSCN) and its accompanying artery, superficial lateral sural artery (SLSA), and a lateral sural neurocutaneous flap was designed. METHODS: Five fresh adult cadaver legs perfused with red latex were dissected to observe the course and relationship between LSCN and SLSA. The outer diameter of SLSA at its origin was measured. Then a lateral sural neurocutaneous flap was designed and used to repair soft tissue defects in six patients. RESULTS: The anatomic results showed that the SLSA gave rise to branches that followed the LSCN and ramified into terminals at the ramification of the nerve. It originated directly from the popliteal artery 4.2 ± 0.2 mm above the fibular head, where its outer diameter was 0.96 ± 0.23 mm. Several perforators penetrated from the crural fascia and anastomosed to the SLSA, creating a fine anastomotic network. The clinical results showed that the size of the flap ranged from 12 × 6 cm to 25 × 8 cm. All six flaps survived completely without complications. Follow-up ranged from 6 to 18 months with 11 months on average. The overall contour and sensory recovery of the flap were satisfied. CONCLUSION: A free innervated flap may be elevated safely based on the LSCN and its accompanying vessels. It provides an alternative in reconstruction of soft tissue defects where sensory recovery is important.

Sural nerve harvest for infants: integrated with information based on anatomical dissections

Background/aim: The aim of the present study was to determine the course and possible variations of the sural nerve with all anatomical details in human fetal cadavers. Materials and methods: This study was performed on 60 fetal cadavers. Formation type and level of the sural nerve was detected. Results: According to trimesters, it was determined that the mean transverse and vertical distance between the lowest point of the LM and the SN varied between 1.1 and 2.9 mm and 1.54 and 3.58 mm, respectively. Type 2 was the most common seen type of sural nerve (35.83%). It was determined that the sural nerve was mostly formed at the middle third of the leg (42.5%). Conclusion: Sural nerve graft with the knowledge of the anatomical details may be used for peripheral nerve reconstruction is required in congenital lesions, such as facial paralysis, obstetric brachial paralysis, and posttraumatic lesions in infants and children.

Inferior alveolar nerve reconstruction in extensive mandibular resection: Technical notes.

The inferior alveolar nerve (IAN) is a sensitive branch of the mandibular nerve innervating the lower lip, the chin, the buccal mucosa and the teeths. Lesions of the IAN are reported to occur in the 64,4% of maxillo-facial procedures, leading to anesthesia, hypoestesia and/or neurogenic discomfort. An extensive segment of the nerve can be moreover removed during mandibular resection for benign or malignant pathologies. Nervous grafts can be used in these cases to restore the nerve continuity. In order to optimize the procedure and to allow a concomitant mandibular osseous reconstruction, the Authors identified several standardized steps. The technique described allows to perform confortable and safe nervous anastomoses and to reduce the risk of damage and tension during the flap insetting phases.

Comparison of neuropathic pain characteristics associated with total brachial plexus injury before and after surgical repair: A retrospective study.

OBJECTIVES: The goal of this study was to compare clinical characteristics of neuropathic pain associated with total brachial plexus injury before and after surgeries and to correlate possible contributing factors concerning to the pain prognosis. PATIENTS AND METHODS: Thirty patients with both total brachial plexus injury and neuropathic pain were included. Neuropathic pain was evaluated in terms of pain intensities, symptoms and regions. Pain intensities were evaluated by a visual analogue scale. The Neuropathic Pain Symptoms Inventory questionnaire and body maps were used to compare the pain symptoms and regions. Demographic data, injury and repair information were evaluated to analyze the possible factors influencing the prognosis. RESULTS: The average pain score of all participants was 7.13 ± 2.46 preoperatively and 5.40 ± 2.08 postoperatively. All patients were divided into Pain Relief Group and Pain Aggravation Group. Older age (p = 0.042), machine traction injury (p = 0.019)and nerve transplantation(p = 0.015) seemed to be related with pain aggravation. Paroxysmal pain was aggravated after surgical repairs (p = 0.041), while paresthesia/dysesthesia improved after surgery (p = 0.003). The permanent component of the pain (spontaneous pain) did not show any significant change (p = 0.584). Pain in C5 (p < 0.001) and C6 (p = 0.031) dermatomes got relieved after surgery. CONCLUSION: This study revealed the neuropathic pain of most patients with total brachial plexus injury was alleviated after neurosurgery, and the pain prognosis of different symptoms and regions varied after the nerve repair.

Isolated Nerve Grafting for a Young Patient with a Complete Common Peroneal Nerve Palsy Following a Traumatic Knee Dislocation: A case report.

BACKGROUND: Common peroneal nerve (CPN) injury following a knee dislocation is a serious problem, and an optimal treatment is yet to be established. We report a case of complete CPN palsy following a knee dislocation treated with sural nerve grafting. CASE: A 19-year-old man suffered a knee injury during a hurdle race. Diagnosis in a previous hospital revealed a complex ligament injury with CPN palsy. Ten weeks following injury, he was admitted to our institution because of a lack of neurological improvement. Considering the grade 0 results obtained in the manual muscle test (MMT) of tibialis anterior (TA) and extensor hallucis longus (EHL), the patient was diagnosed with complete neurotmesis of CPN, and surgery was performed. Operative findings revealed CPN discontinuity and an extended nerve defect length of 15 cm; therefore, sural nerve grafting was performed to repair the CPN injury. One year postoperatively, a grade 1 result from MMT of TA and EHL indicated a gradual neurological recovery. Three years postoperatively, MMT of TA and EHL showed significant improvement to grade 4+ and grade 4, respectively, and he could walk and jog without a knee brace. DISCUSSION: Nerve graft length of >6 cm has shown limited success, and their efficacy for the treatment of CPN palsy following knee dislocations is controversial. However, young patients with complete CPN lesion are more likely to recover regardless of the length of nerve injury. Therefore, in such cases, nerve grafting can be considered as one of the treatments for complete CPN lesion following knee dislocations.

An Anatomic Variant of the Ansa Cervicalis Precluding Its Use as a Donor Nerve.

BACKGROUND: The ansa cervicalis is useful for cranial nerve repair, and may be harvested without apparent morbidity. Herein we report an unusual and surgically relevant anatomic variant of the ansa cervicalis. METHODS: An adult male with left parotid adenoid cystic carcinoma underwent parotidectomy with upper-division facial nerve resection and planned interposition repair using the ansa cervicalis. The ipsilateral hypoglossal nerve was identified, together with a descending branch producing strap muscle contraction when stimulated. This presumed descendens hypoglossi was unusually large in caliber; further dissection revealed continuity with the vagus nerve. RESULTS: Ansa cervicalis harvest was aborted when its separation from vagus nerve epineurium was not possible. The sural nerve was alternatively harvested. The patient awoke with left vocal fold palsy, which completely resolved within 3 months. CONCLUSION: Anatomic variants of the ansa cervicalis exist that may preclude graft harvest and place the vagus nerve at risk of inadvertent injury.

Ipsilateral S2 nerve root transfer to pudendal nerve for restoration of external anal and urethral sphincter function: an anatomical study.

Patients suffer bilateral sacral plexus injuries experience severe problems with incontinence. We performed a cadaveric study to explore the anatomical feasibility of transferring ipsilateral S2 nerve root combined with a sural nerve graft to pudendal nerve for restoration of external anal and urethral sphincter function. The sacral nerve roots and pudendal nerve roots on the right side were exposed in 10 cadavers. The length from S2 nerve root origin to pudendal nerve at inferior border of piriformis was measured. The sural nerve was used as nerve graft. The diameters and nerve cross-sectional areas of S2 nerve root, pudendal nerve and sural nerve were measured and calculated, so as the number of myelinated axons of three nerves on each cadaver specimen. The length from S2 nerve root to pudendal nerve was 10.69 ± 1.67 cm. The cross-sectional areas of the three nerves were 8.57 ± 3.03 mm2 for S2, 7.02 ± 2.04 mm2 for pudendal nerve and 6.33 ± 1.61 mm2 for sural nerve. The pudendal nerve contained approximately the same number of axons (5708 ± 1143) as the sural nerve (5607 ± 1305), which was a bit less than that of the S2 nerve root (6005 ± 1479). The S2 nerve root in combination with a sural nerve graft is surgically feasible to transfer to the pudendal nerve for return of external urethral and anal sphincter function, and may be suitable for clinical application in patients suffering from incontinence following sacral plexus injuries.

Surgical anatomy of the ovine sural nerve for facial nerve regeneration and reconstruction research.

The lack of a clinically relevant animal models for research in facial nerve reconstruction is challenging. In this study, we investigated the surgical anatomy of the ovine sural nerve as a potential candidate for facial nerve reconstruction, and performed its histological quantitative analysis in comparison to the buccal branch (BB) of the facial nerve using cadaver and anesthetized sheep. The ovine sural nerve descended to the lower leg along the short saphenous vein. The length of the sural nerve was 14.3 ± 0.5 cm. The distance from the posterior edge of the lateral malleolus to the sural nerve was 7.8 ± 1.8 mm. The mean number of myelinated fibers in the sural nerve was significantly lower than that of the BB (2,311 ± 381vs. 5,022 ± 433, respectively. p = 0.003). The number of fascicles in the sural nerve was also significantly lower than in the BB (10.5 ± 1.7 vs. 21.3 ± 2.7, respectively. p = 0.007). The sural nerve was grafted to the BB with end-to-end neurorrhaphy under surgical microscopy in cadaver sheep. The surgical anatomy and the number of fascicles of the ovine sural nerve were similar of those reported in humans. The results suggest that the sural nerve can be successfully used for facial nerve reconstruction research in a clinically relevant ovine model.