Variations in sural nerve formation and course in fetuses.

To investigate variations regarding the formation and course of the sural nerve (SN). We dissected 60 formalin-fixed Brazilian fetuses (n = 120 lower limbs) aged from the 16th to 34th weeks of gestational age. Three incisions were made in the leg to expose the SN, and the gastrocnemius muscle was retracted to investigate the SN course. Statistical analyses regarding laterality and sex were performed using the Chi-square test. Eight SN formation patterns were classified after analysis. Type 4 (in which the SN is formed by the union of the MSCN with the LSCN) was the most common SN formation pattern. Although there was no statistical association between the formation patterns and the lower limb laterality (p = 0.9725), there was as to sex (p = 0.03973), indicating an association between anatomical variation and sex. The site of branch joining was in the distal leg most time (53.75%). In all lower limbs, the SN or its branches crossed from the medial aspect of the leg to the lateral margin of the calcaneal tendon (CT). Most often, the SN is formed by joining the MSCN and the LSCN in the distal leg. The SN or its branches ran close to the saphenous vein, crossed the CT from medial to lateral, and distributed around the lateral malleolus.

A Cohort Study on Neuropathic Pain of the Sural Nerve-Can Neurectomy Be Considered a Valid Treatment Option?

BACKGROUND: Sural nerve neuroma is often caused by an injury during prior surgery, for example, osteosynthesis or ligament refixations at ankle level. Different surgical techniques to treat neuroma have been described. Neurectomy of an injured symptomatic sural nerve has been described as a treatment option for neuropathic pain. The aim of this study was to evaluate the outcomes of this technique to operatively treat sural nerve neuroma in our department. METHODS: From 2010 to 2020, a total of 30 consecutive patients with neuropathic pain and suspected neuroma of the sural nerve underwent sural nerve neurectomy. A medical chart review was performed to collect patient-, pain-, and treatment-specific factors. Outcomes were registered. RESULTS: After neurectomy, 22 patients (73.3%) had persisting pain. In logistic regression models evaluating the risk of persisting pain after sural nerve neurectomy, no independent predictor of higher risk of persisting pain could be identified. CONCLUSION: For sural nerve neuromas, neurectomy remains an option as the surgical morbidity is minor, but patients need to be counseled that only a fourth of those undergoing surgery will be pain-free afterward.

The arthroscopic all-inside ankle lateral collateral ligament repair is a safe and reproducible technique.

PURPOSE: Neurovascular structures around the ankle are at risk of injury during arthroscopic all-inside lateral collateral ligament repair for the treatment of chronic ankle instability. This study aimed to evaluate the risk of damage to anatomical structures and reproducibility of the technique amongst surgeons with different levels of expertise in the arthroscopic all-inside ligament repair. METHODS: Twelve fresh-frozen ankle specimens were used for the study. Two foot and ankle surgeons with different level of experience in the technique performed the procedure on 6 specimens each. The repair was performed following a standardized procedure as originally described. Then, an experienced anatomist dissected all the specimens to evaluate the outcome of the ligament repair, any injuries to anatomical structures and the distance between arthroscopic portals and the superficial peroneal nerve (SPN) and sural nerve. RESULTS: Dissections revealed no injury to the nerves assessed. Mean distance from the anterolateral portal and the SPN was of 4.8 (range 0.0-10.4) mm. The mean distance from the accessory anterolateral portal to the SPN and sural nerve was of 14.2 (range 7.1-32.9) mm and 28.1 (range 2.8-39.6) mm, respectively. The difference between the 2 surgeons' groups was non-statistically significant for any measurement (mm). In all specimens both fascicles of the anterior talofibular ligament were reattached onto its original fibular footprint. The calcaneofibular ligament was not penetrated in any specimen. CONCLUSIONS: The all-inside arthroscopic lateral collateral ligament repair is a safe and reproducible technique. The clinical relevance of this study is that this technique provides a safe and anatomic reattachment of the anterior talofibular ligament, with minimal risk of injury to surrounding anatomical structures regardless of the level of experience with the technique.

Reconstruction of complex tissue defect of forearm with a chimeric flap composed of a sural neurocutaneous flap and a vascularized fibular graft: A case report.

One-stage reconstruction of composite bone and soft-tissue defects in the forearm remains a tough challenge. Here, we present a case of reconstruction of complex tissue defect at forearm with a chimeric flap consisting of a sural neurocutaneous flap and a fibular graft. A 61-year-old man suffered from a machine crush injury in his left forearm, resulting in a complex tissue defect including extensive dorsomedial soft-tissue, digit extensor muscles of 2-4 fingers, the muscle flexor carpi ulnaris, the ulna bone with 5.5 cm in length, segmental injuries of ulna nerve and vessels, and the radius fracture. The defects were reconstructed by a modified chimeric flap, in which the sural neurocutaneous flap supplied by a peroneal perforator was used to repair the soft-tissue defect and the vascularized fibular graft was used to repair the ulna defect. The two components were supplied by the peroneal vessels. The ulnar nerve defect was bridged by a sural nerve graft. The venous congestion caused by thrombosis was observed at 24 hours postoperatively. After the venous anastomosis was reperformed, the flap survived completely without other complications. Bone healing was achieved at the 7-month follow-up. The index and middle fingers reached nearly full range of motion, while the ranges of motion of metacarpophalangeal joint of the ring and little fingers were less than 60 degrees. The results showed that the modified chimeric flap may be an option for reconstruction of complex tissue defect in the forearm.

The surgical anatomy of the sural nerve: An ultrasound study.

The aim of this study was (a) to examine the anatomy of the sural nerve (SN) in a sample of 30 patients and (b) to analyze the incidence of different origins of the SN, and the distance of the SN from planned arthroscopic portals. An ultrasound (USG) examination of the SN was performed bilaterally on thirty healthy patients with no history of surgery or trauma of the lower limb. The SNs were classified into six main types of pattern, with an additional category for new and unclassified types. Each of Types 1 and 3 had two subdivisions. The distances from the superior border of the calcaneal tuberosity to the three simulated arthroscopy portal sites (Z1, Z1.5, Z2) to the SN were measured. A total of 30 patients (n = 60 limbs) with an average age of 27 ± 7.5 years were examined and the SN was visualized in all cases. The most common origin was Type 3A, accounting for 30% of limbs. Type 2 was the second most common seen in 18.3%. The distances of the SN from arthroscopic portal placement sites above the lateral malleolus were 2.07 ± 0.39 cm at the Z1 portal, 2.15 ± 0.38 cm at Z1.5, and 2.28 ± 0.33 cm at Z2. The variability in the anatomy of the SN warrants the use of USG to locate it accurately, thus preventing iatrogenic injury when portals are placed for arthroscopy, improving proper administration of anesthesia, and helping to localize the nerve for graft harvesting. Clin. Anat. 31:450-455, 2018. © 2017 Wiley Periodicals, Inc.

Peripheral Nerve Schwannoma: A Review of Varying Clinical Presentations and Imaging Findings.

A schwannoma or neurilemmoma is a benign, isolated, noninvasive, and encapsulated tumor originating from Schwann cells of the peripheral nerve sheath. The incidence of a schwannoma occurring in the foot and ankle is rare, with prevalence rate of 1% to 10%. Schwannomas have no sex predilection, and they commonly occur in patients in their fourth decade. Malignant transformation of benign schwannoma is unusual; however, it is important to note that malignant variants of schwannomas do exist and account for about 5% to 10% of all soft tissue sarcomas. We present 3 cases of benign schwannoma in the lower extremity. All 3 patients presented with varying clinical symptoms, including pain, paresthesia, weakness, and a palpable mass. A schwannoma was eventually diagnosed in all 3 patients. We discuss and review the known entities of peripheral nerve schwannoma and describe the clinical and imaging findings and therapeutic strategies for treating and diagnosing peripheral nerve schwannoma.

The Distally Based Sural Flap for the Reconstruction of Ankle and Foot Defects in Pediatric Patients.

BACKGROUND: Skin and soft tissue defects at the level of the ankle and the heel remain a great challenge for plastic and reconstructive surgeons. There were just a few reports on the use of distal-based sural flap in pediatric patients. The purpose of this study was to introduce our experience in the treatment of skin and soft tissue defects of the pediatric feet by using this distally based sural neurocutaneous flap together with some technical modifications for a large-sized defect. METHODS: From July 2004 to October 2012, a total of 36 children younger than 12 years were treated with distally based sural flap for a variety of soft tissue defects of the foot and the ankle. All patients experienced a traffic accident. Thirty-four patients received standard distal-based reverse sural flaps, and 2 children received the flaps with nerve and vein sparing. RESULTS: The duration of follow-up varied from 3 to 48 months. All flaps survived completely. Two flaps presented vascular insufficiency and resulted in partial distal superficial necrosis (10%-20%). Two children had a compressive ulcer because of improper shoes wearing. There were no complaints related to the killing of the sural nerve. CONCLUSIONS: The distally based sural flap is an excellent choice in pediatric patients for covering defects of the lower leg and the foot because of its simplicity, versatility, low risk, and minimal donor site morbidity.

Nerve conduction block in diabetic rats using high-intensity focused ultrasound for analgesic applications.

BACKGROUND: Nerve conduction block using high-intensity focused ultrasound (HIFU) has been conducted with nerves of mixed fibres in normal animal models. This study tested the feasibility and safety of HIFU for sensory nerve conduction block in diabetic neuropathic nerves to determine its potential for pain relief. METHODS: Diabetes was induced in Sprague-Dawley rats using streptozotocin, and HIFU at 2.68 MHz was used for the block. This study consisted of two sections, in vitro and in vivo. For the in vitro experiments, the entire contiguous sciatic-sural nerves were obtained. Compound action potentials and sensory action potentials were recorded in the sciatic and sural nerves, respectively. For the in vivo experiments, compound muscle action potentials (CMAPs) were recorded from the gastrocnemius muscles. All data were expressed as median (range). RESULTS: The in vitro results showed that HIFU temporarily inhibited sensory action potentials of the control and diabetic rat nerves to 33.9 (8.2) and 14.0 (10.7)% of the baseline values, respectively, whereas the compound action potentials were suppressed to 53.6 (8.4) and 76.2 (7.5)% of baseline, respectively. The in vivo results showed that HIFU acutely blocked CMAPs to 32.9 (12.6) and 19.9 (10.9)% of baseline in control and diabetic rat nerves, respectively. Measurements of CMAPs and histological exanmination were used for indirect assessment of the safety of the HIFU technique. CONCLUSIONS: High-intensity focused ultrasound safely and reversibly suppressed nerve conduction in diabetic rat nerves when the stimulation parameters were appropriate. The results suggest that HIFU may have potential to block sensory nerves reversibly and provide peripheral pain relief.

Spontaneous intraneural hematoma of the sural nerve.

Symptomatic intraneural hemorrhage occurs rarely. It presents with pain and/or weakness in the distribution following the anatomic innervation pattern of the involved nerve. When a purely sensory nerve is affected, the symptoms can be subtle. We present a previously healthy 36-year-old female who developed an atraumatic, spontaneous intraneural hematoma of her sural nerve. Sural dysfunction was elicited from the patient's history and physical examination. The diagnosis was confirmed with magnetic resonance imaging, and surgical decompression provided successful resolution of her preoperative symptoms. To our knowledge, this entity has not been reported previously. Our case highlights the importance of having a high index of suspicion for nerve injury or compression in patients whose complaints follow a typical peripheral nerve distribution. Prior studies have shown that the formation of intraneural hematoma and associated compression of nerve fibers result in axonal degeneration, and surgical decompression decreases axonal degeneration and aids functional recovery.

One-stage reconstruction of complex lower extremity deformity combining Ilizarov external fixation and sural neurocutaneous flap.

BACKGROUND: Complex lower extremity deformities include multidirectional foot and ankle deformities, which are complicated therapeutic and surgical challenges. Correction often requires several stages, which is time consuming and costly. The need to restore the physical, mechanical, and cosmetic aspects of the lower extremity results in a difficult balancing act between these concerns and the deformity correction and soft tissue reconstruction. METHODS: Between January 2009 and September 2011, we treated 5 patients with multidirectional foot and ankle deformities. Significant mobility limitation was caused by abnormal scarring, which led to abnormal gait and weight-bearing regions. We used a sural neurocutaneous flap to repair the soft tissue defects after scar-tissue removal in all patients and placed a circular hinged Ilizarov external fixator for gradual correction. RESULTS: All the flaps survived and resulted in good texture match and contour. The follow-up period was 19 to 26 months. The correction lasted 3 to 5 months, and all of the patients were able to walk with satisfactory gaits and without assistance. We encountered no complications, such as pin-track infection or drop foot in our series. CONCLUSION: Our approach, combining a sural neurocutaneous flap and Ilizarov external fixation, was a reliable and effective tool for one-stage reconstruction of complex lower extremity deformities.

Cross-facial nerve grafting for facial reanimation.

Dynamic facial reanimation is the gold standard treatment for a paralyzed face. Over the last century, multiple nerves have been utilized for grafting to the facial nerve in an attempt to produce improved movement. However, in recent years, the use of cross facial nerve grafting with a second stage gracilis free flap has gained popularity due to the ability to generate a spontaneous smile and facial movement. Preoperative history taking and careful examination, as well as pre-surgical planning, are imperative to whether cross facial nerve grafting with a second stage gracilis free flap is appropriate for the patient. A sural nerve graft is ideal given the accessibility of the nerve, the length, as well as the reliability and ease of the nerve harvest. The nerve can be harvested using a small incision, which leaves the patient with minimal post operative morbidity. In this chapter, we highlight the pearls and pitfalls of cross facial nerve grafting.

Antinociceptive and antiallodynic effects of Momordica charantia L. in tibial and sural nerve transection-induced neuropathic pain in rats.

OBJECTIVE: This study was designed to investigate the ameliorative potential of Momordica charantia L. (MC) in tibial and sural nerve transection (TST)-induced neuropathic pain in rats. MATERIALS AND METHODS: TST was performed by sectioning tibial and sural nerve portions (2 mm) of the sciatic nerve, and leaving the common peroneal nerve intact. Acetone drop, pin-prick, hot plate, paint-brush, and walking track tests were performed to assess cold allodynia, mechanical and heat hyperalgesia, and dynamic mechanical allodynia and tibial functional index, respectively. The levels of tumour necrosis factor (TNF)-alpha and thio-barbituric acid reactive substances (TBARS) were measured in the sciatic nerve as an index of inflammation and oxidative stress. MC (all doses, orally, once daily) was administered to the rats for 24 consecutive days. RESULTS: TST led to significant development of cold allodynia, mechanical and heat hyperalgesia, dynamic mechanical allodynia, and functional deficit in walking along with rise in the levels of TBARS and TNF-alpha. Administration of MC (200, 400, and 800 mg/kg) significantly attenuated TST-induced behavioural and biochemical changes. Furthermore, pretreatment of BADGE (120 mg/kg, intraperitoneally) abolished the protective effect of MC in TST-induced neuropathic pain. CONCLUSIONS: Collectively, it is speculated that PPAR-gamma agonistic activity, anti-inflammatory, and antioxidative potential is critical for antinociceptive effect of MC in neuropathic pain.

The extended distally based sural neurocutaneous flap for foot and ankle reconstruction: a retrospective review of 10 years of experience.

The distally based sural neurocutaneous flap has been used for coverage of defects in foot and ankle for years. Conventional flaps do not extend to the upper third of the leg, which limits its application. The current study presents results using extended distally based sural neurocutaneous flaps for reconstruction of extensive soft tissue defects of the foot and ankle in 21 patients. All injuries occurred from 2001 to 2011 as a result of a traumatic event. Follow-up of 21 patients ranged from 7 months to 5 years after surgery. All 21 flaps survived successfully. The largest flap used measured 26 × 15 cm. Complications included 1 distal marginal necrosis and 2 slight venous congestions. The extended distally based sural neurocutaneous flap is a good alternative for extensive soft tissue defects of foot and ankle. The operative techniques with several simple modifications in harvesting the flaps are easy to handle and will not prolong the operation time.

Safety profile of sural nerve in posterolateral approach to the ankle joint: MRI study.

The posterolateral approach to ankle joint is well suited for ORIF of posterior malleolar fractures. There are no major neurovascular structures endangering this approach other than the sural nerve. The sural nerve is often used as an autologous peripheral nerve graft and provides sensation to the lateral aspect of the foot. The aim of this paper is to measure the precise distance of the sural nerve from surrounding soft tissue structures so as to enable safe placement of skin incision in posterolateral approach. This is a retrospective image review study involving 64 MRI scans. All measurements were made from Axial T1 slices. The key findings of the paper is the safety window for the sural nerve from the lateral border of tendoachilles (TA) is 7 mm, 1.3 cm and 2 cm at 3 cm above ankle joint, at the ankle joint and at the distal tip of fibula respectively. Our study demonstrates the close relationship of the nerve in relation to TA and fibula in terms of exact measurements. The safety margins established in this study should enable the surgeon in preventing endangerment of the sural nerve encountered in this approach.

Percutaneous versus open repair of acute Achilles tendon ruptures.

BACKGROUND: Controversy exists regarding the optimal treatment for acute Achilles tendon ruptures. Conservative and surgical treatments have been reported with variable results and complications rates. The purpose of this study is to compare the postoperative clinical and functional results of percutaneous versus open repair of acute Achilles tendon ruptures. MATERIALS AND METHODS: We present 34 patients with acute Achilles tendon ruptures treated with open and percutaneous surgical repair. There were 15 patients who had open surgical repair and 19 patients who had percutaneous repair. The mean follow-up was 22 months (range 10-24 months) for the open repair group and 20 months (range 9-24 months) for the percutaneous repair group; no patient was lost to follow-up. Postoperative rehabilitation was the same for both groups. Wound healing, complications, ankle range of motion, and patients' return to work, activity level, weight-bearing, and subjective assessment of their treatment were recorded. RESULTS: No significant difference was observed with respect to any of the examined variables between the open and percutaneous repair groups. Tendon healing was observed in all patients of both groups by 7-9 weeks. The mean time of patients' return to work was 7 weeks for the open repair group and 9 weeks for the percutaneous repair group. All patients were capable of full weight bearing by the 8th postoperative week time; the time to return to previous activities including non-contact sports was 5 months for both groups. All patients expressed satisfaction and graded their treatment as good. As expected, cosmetic appearance was significantly better in the percutaneous repair group. One patient who had open repair experienced skin incision pain and dysesthesia and graded his operation as fair. No patient experienced other complications such as re-rupture, infection, sural neuroma, or Achilles tendinitis within the period of this study. CONCLUSIONS: The present study showed similarly successful clinical and functional results after both open and percutaneous repair of acute Achilles tendon ruptures are similar. Cosmetic appearance is superior in the group of patients who had a percutaneous treatment.

Transfer of the extensor digiti minimi and extensor carpi ulnaris branches of the posterior interosseous nerve to restore intrinsic hand function: case report and anatomic study.

PURPOSE: To present a technique for restoration of ulnar intrinsic function using a nerve transfer of the extensor carpi ulnaris (ECU) and extensor digiti minimi (EDM) nerve branches of the posterior interosseous nerve (PIN) to the deep branch of the ulnar nerve in the forearm when the anterior interosseous nerve is unavailable. METHODS: We dissected 6 cadaveric upper extremities to identify the location of the EDM and ECU branches of the PIN and their distance to the ulnar nerve near the wrist. We present a case of a high combined median and ulnar nerve injury. We performed transfer of the EDM branch and 1 of the branches to the ECU of the PIN to the motor component of the ulnar nerve for intrinsic hand function. RESULTS: Our anatomic data demonstrate the branching pattern of the PIN and the length of regeneration and nerve graft required. Our patient required a 10-cm nerve graft, and the length of regeneration to reach the wrist was 19 cm. The patient recovered useful but incomplete reinnervation of the intrinsic muscles and rated hand recovery at 70%. CONCLUSIONS: Transfer of the EDM and ECU branches of the PIN to the motor component of the ulnar nerve is feasible with the use of a nerve graft. Using some of the branches to the ECU as well increases the axonal load to maximize muscle reinnervation. CLINICAL RELEVANCE: Proximal ulnar nerve injuries with paralysis of the intrinsic hand muscles lead to severe disability. Distal nerve transfers eliminate key factors that result in poor outcomes by allowing for faster muscle reinnervation. This nerve transfer had no functional donor morbidity and could be useful in the setting of a combined high median and ulnar nerve injury.

Treatment of a patient with small fiber pathology using nerve biopsy and grafting: a case report.

Small fiber pathology is a common clinical entity with a variable clinical presentation and etiology. Unfortunately, little has been described regarding its treatment because a majority of cases are idiopathic. Hence, treatment often consists of symptomatic management of pain and autonomic dysfunction. This report describes a patient who was presented with an undiagnosed pain syndrome thought to be affecting nerves within both lower extremities and causing significant pain. A sural nerve biopsy was performed for diagnostic purposes and nerve repair was performed using Avance nerve allograft (AxoGen Inc., Alachua, FL). Light microscopic evaluation was unremarkable, but electron microscopy revealed small fiber pathology. Postoperatively, the patient experienced a complete resolution of her pain on the involved extremity. These results suggest a potential, novel approach for treatment of such cases and possible mechanisms for the patient's clinical improvement are explored.

Comparative study of two types of distally based sural neurocutaneous flap for reconstruction of lower leg, ankle, and heel.

BACKGROUND: Soft-tissue defects in the lower leg, ankle, and heel often require reconstruction with local or free flaps. We try to compare the clinical outcome and complications following transfer of a perforator pedicle-based sural neurocutaneous flap (P-NCF) or a fascia pedicle-based sural neurocutaneous flap (F-NCF). METHODS: Between March 2007 and December 2010, 92 patients (mean, 36.52 years) with a distal leg soft-tissue defect were included. Forty-eight patients treated with P-NCF were compared with 44 patients treated by F-NCF. The etiology, size, and operation time were noted. The clinical outcomes and the complications have been analyzed. RESULTS: Age, sex, and defect etiology, duration of surgery and, area of flaps did not reveal significant differences in term of clinical outcome. Minor flap necrosis (<10%) was observed in 20.5% of the F-NCF group and 6.25% of the P-NCF group. Patient satisfaction, aesthetic appearance, and functional outcome were comparable in both groups. CONCLUSION: A high rate of complications was observed in the F-NCF group. Based on our finding, a perforator-based flap is more reliable than a fascia-based flap and the two types of flaps are both valuable choices for reconstructive surgery.