Lateral Sural Nerve Research Articles

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

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. 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. 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. 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 determination of safe zones for arthroscopic portal placement into the posterior knee by mapping the courses of neurovascular structures in relation to bony landmarks.

Minimally invasive surgery in the posterior knee is high risk for iatrogenic injury to popliteal neurovascularneurovasculature structures. This study aimed to use reliable landmarks to define safe zones for arthroscopic portal placement into the posterior knee. Distances were measured between bony landmarks and neurovascular structures within the popliteal fossa using 45 formalin-embalmed cadavers: small saphenous vein (SSV), medial (MCSN) and lateral (LCSN) cutaneous sural nerves, tibial nerve (TN), common fibular nerve (CFN), popliteal vein (PV) and artery (PA). The structures were measured in relation to medial (MEF) and lateral (LEF) femoral epicondyle, medial (MCT) and lateral (LCT) tibial condyle and the midpoint between the landmarks. The mean distance (mm) between MEF and structures was, male and female, respectively: SSV 37.6 + 12.5, 37.9 + 8.2; MCSN 39.2 + 14, 38.8 + 10.1; TN 39.4 + 10.2, 38.0 + 8.1; PV 38.4 + 12.9, 32.8 + 5.6; PA 38.4 + 12.1, 34.6 + 4.9. At midpoint and MCT all structures medialized between 5 and 28%. The mean distance between LEF and structures was, male and female, respectively: CFN 13.4 + 8.2, 8.4 + 9.1; LCSN 24.9 + 7.3, 18.4 + 10.4. At midpoint and LCT the CFN lateralized by 37-42% and the LCSN medialized by 8-9%. Results suggest posteromedial portal placement can be safely established < 20mm from the medial femoral epicondyle, tibial condyle or the midpoint between the two landmarks. Posterolateral portal placement is of higher risk, and entry point is 18mm from the lateral femoral epicondyle, tibial condyle or the midpoint between the two landmarks in males and 12mm in females. These landmarks will allow safe portal placement in 99% of cases.

Sonographic Tracking of the Lower Limb Peripheral Nerves: A Pictorial Essay and Video Demonstration.

Compared with the upper limbs, sonographic tracking of peripheral nerves in the lower limbs is more challenging. The overlying muscles are larger, hindering visualization of the deeply embedded nerves by using a linear transducer. The use of a curvilinear transducer-providing an extended view with better penetration for the field of interest-may be useful for scanning the nerves in the hip and thigh. Application of the Doppler mode helps localization of the target nerve by identifying the accompanying vessels. Aiming to demonstrate the relevant tracking techniques, the present article comprises a series of ultrasound images and videos showing how to scan the nerves in the lower limb, that is, femoral, obturator, pudendal, lateral femoral cutaneous, sciatic, saphenous, sural, tibial, and peroneal nerves.

A Cystic Mass in the Popliteal Fossa and Its Differential Diagnosis.

A Cystic Mass in the Popliteal Fossa and Its Differential Diagnosis.

Distally Based Sural Artery Adipofascial Flap based on a Single Sural Nerve Branch: Anatomy and Clinical Applications.

BackgroundThe distally based sural artery flap is a reliable, local reconstructive option for small soft tissue defects of the distal third of the leg. The purpose of this study is to describe an adipofascial flap based on a single sural nerve branch without sacrificing the entire sural nerve, thereby preserving sensibility of the lateral foot.MethodsThe posterior aspect of the lower limb was dissected in 15 cadaveric limbs. Four patients with soft tissue defects over the tendo-achilles and ankle underwent reconstruction using the adipofascial flap, which incorporated the distal peroneal perforator, short saphenous vein, and a single branch of the sural nerve.ResultsFrom the anatomical study, the distal peroneal perforator was situated at an average of 6.2 cm (2.5-12 cm) from the distal tip of the lateral malleolus. The medial and lateral sural nerve branches ran subfascially and pierced the muscle fascia 16 cm (14-19 cm) proximal to the lateral malleolus to enter the subcutaneous plane. They merged 1-2 cm distal to the subcutaneous entry point to form the common sural nerve at a mean distance of 14.5 cm (11.5-18 cm) proximal to the lateral malleolus. This merging point determined the pivot point of the flap. In the clinical cases, all patients reported near complete recovery of sensation over the lateral foot six months after surgery. All donor sites healed well with a full range of motion over the foot and ankle.ConclusionsThe distally based sural artery adipofascial flap allowed for minimal sensory loss, a good range of motion, an aesthetically acceptable outcome and can be performed by a single surgeon in under 2 hours.

Variation in the Mode of Origin and Level of Formation of Sural Nerve

Variations of nerve are not only of anatomic and embryological interest but also of clinical importance. Their adequate knowledge will help in increasing surgical precision and decreasing morbidity. In present study variations in mode of origin and level of formation of sural nerve was studied. The material for the present study comprised of 60 lower extremities belonging to 30 adult human cadavers obtained from Deptt. of Anatomy, GMC, Amritsar. The sural nerve was identified and its mode of origin and level of formation was studied. In present study, sural nerve was formed by union of medial sural nerve (from tibial nerve or from nerve to medial head of gastrocnemius) and lateral sural nerve (from common peroneal nerve) in 83.33% limbs. It was formed by medial sural nerve alone in 15% limbs. In 1.67% medial and lateral sural nerve were separate. The site of formation was in middle 1/3rd of leg in 20% limbs and distal 1/3rd of leg in 80% limbs.

Clinical and anatomical study of the distally based lesser saphenous veno-lateral sural neurocutaneous flap for lower extremity coverage

BackgroundThe distally based sural flap has been widely and successfully used to reconstruct soft tissue defects of the distal third of the lower leg and foot. Sensory loss and venous congestion are possible complications of this treatment, but there has been limited research focused on improving the sensory loss and veneous congestion. This study aimed to determine the spatial relationship between the lesser saphenous vein and the cutaneous nerves, the venous anatomy in the lower leg, and the nerve distribution in the lateral dorsum of the foot, and we presented our clinical experience. Materials and methodsTwenty freshly amputated lower limbs were dissected in the 2h following amputation. The lesser saphenous vein, medial/lateral sural nerve, and sural nerve were identified. Based on the anatomical studies, an island flap supplied by the vascular axis of the lesser saphenous vein and the lateral sural nerve was designed for clinical reparative applications in 24 cases. ResultsWe indicated the spatial relationship between the lesser saphenous vein and the cutaneous nerves and the venous anatomy in the lower leg. Among 24 flaps, 21 showed complete survival (87.5%), while marginal flap necrosis occurred in two patients (8.33%) and distal wound dehiscence in another (4.17%). No symptomatic neuromas were observed. Their appearance and functioning were satisfactory, with filling maintained in the heel and lateral side of the foot. ConclusionThe distally based lesser saphenous veno-lateral sural neurocutaneous flap provides effective coverage of variable-sized soft tissue defects on the lower third of the lower leg and foot, without sensory loss and venous congestion.

Anatomic assessment and clinical application of the lateral sural nerve-lesser saphenous vein vascular plexus island flap

Objective To investigate the practical anatomy and clinical applications of the lateral sural nerve-lesser saphenous vein vascular plexus island flap with median sural nerve preserved.Methods Ten lower limbs injected with color red latex and 20 fresh limbs were observed.Based on anatomical studies,the island flap pedicled with the vascular axis of lateral sural nerve and lesser saphenous vein was designed for clinical application in 63 cases.In procedure,the median sural nerve were preserved in donor site and the distal end of the lesser saphenous vein were not ligated.Results The accompanying arteries formed a favourable vascular plexus around the nerve and the vein,lied along the lateral sural nerve and the lesser saphenous vein and nourished the skin through cutaneous branches.The distance of the lateral ankle to the confluent of lateral and median sural nerve was (8.5± 0.8) cm.63 patients with soft tissue defects in the distal leg and foot were repaired.Their appearance and function were satisfaction without feeling lose in the heel and lateral side of the foot.Conclusions The lateral sural nerve-lesser saphenous vein vascular island flap is a reliable source of soft tissue to cover defects in the lower leg and foot.This flap has sufficient blood supply and high survival rate without the sacrifice of the median sural nerve. Key words: Lateral sural nerve; Lesser saphenous vein; Median sural nerve; Flap; Tissue defect

The distally based lateral sural neuro-lesser saphenous veno-fasciocutaneous flap: anatomical basis and clinical applications

BackgroundSoft tissue management around the lower third of the leg and foot presents a considerable challenge to the plastic surgeon. The aim of this research was to investigate the anatomical relationships of artery, nerve, vein and other adjacent structures in the posterolateral region of the calf, and our experience with using a distally based island flap pedicled with the lateral sural nerve and the lesser saphenous vein for soft tissue reconstruction of lower third of leg, foot, and ankle defects in 15 patients.Materials and methodsFive fresh cadavers (ten lower limbs) were infused with colored red latex. The origin of the nutrient vessel of the lesser saphenous vein and the lateral sural nerve was identified. Based on the anatomical studies, an island flap supplied by the vascular axis of the lesser saphenous vein and the lateral sural nerve was designed for clinical reparative applications in 15 cases.ResultsThe nutrient vessel of the lesser saphenous vein and the lateral sural nerve originates from the superficial sural artery, musculocutaneous perforators of the posterior tibial artery, and septocutaneous perforators of the peroneal artery in different segment of the calf. Meanwhile, these vessels have many sub-branches nourishing subcutaneous tissue and skin, form a favorable vascular chain around the nerve and the vein, and also communicate with vascular plexus of superficial and deep fascia. Among 15 flaps, 13 showed complete survival (86.66 %), while marginal flap necrosis occurred in one patient (6.67 %) and distal wound dehiscence in another (6.67 %). Their appearance and function were satisfactory, with feeling maintained in the heel and lateral side of the foot.ConclusionsThe distally based flap pedicled with the lateral sural nerve and lesser saphenous vein was a reliable source for repairing soft tissue defects in the lower leg and foot due to its advantages of infection control, high survival rate, and sufficient blood supply without the need to sacrifice a major blood vessel.

Neuritis ossificans of the tibial, common peroneal and lateral sural cutaneous nerves

We describe a 23-year-old woman with neuritis ossificans involving the tibial, common peroneal and lateral sural nerves. She presented with chronic debilitating posterior knee pain. An MRI scan showed masses in these nerves, biopsy of which revealed a histological diagnosis of neuritis ossificans. Treatment with OxyContin and Neurotin for two years resulted in resolution of symptoms. Follow-up MRI demonstrated a resolution of two of the three masses. There was a persistent area of ossification without associated oedema in the common peroneal nerve. Neuritis ossificans has the histological appearance of myositis ossificans and follows a similar clinical course. The success of conservative treatment in this case suggests that the potential complications of surgical excision can be avoided.

The distally based posterolateral supramalleolar neurofasciocutaneous island flap for coverage defects over the distal third of the leg and foot

A traditional-designed distally based sural flap centralized on the axis of the (medial) sural nerve and the lesser saphenous vein has been used widely for coverage of the distal third of the leg, ankle, malleoli, and foot. However, a variety of 5% to 47% of flap necrosis after the flap elevation and transposition were recorded in the literature. The unreliability of the distal part of the flap, especially when skin paddle located at the proximal third of the leg is at least partly due to their subfascial coursing of the median superficial sural artery and the medial sural nerve as well as the lesser saphenous vein. Based on the anatomic characteristics of the sural nerve and previous angiographic studies, a longitudinal chain-linked axial vascular network along with the sural nerve and the lateral sural nerve had been demonstrated on the posterolateral side of the leg from lateral retromalleolar gutter to the fibular head. A distally based posterolateral supramalleolar neurofasciocutaneous island flap centralized on this longitudinal neurovascular network was designed and used to reconstruct and cover the defects over the distal third of the leg, lateral malleolus, foot, and Achilles tendon. In this report we retrospectively review the clinical outcomes. This flap was used in 11 patients, including six young children aged 3 to 6 years. All flaps survived fully without complications except one flap which experienced postoperative infection which was controlled by dressing change and antibiotic application. Relevant surgical anatomy and detailed surgical techniques for elevation of the flap and its versatile usage are presented. Risks leading to flap necrosis, safe pedicle design, and manipulations etc. are discussed. In conclusion, this distally based posterolateral supramalleolar neurofasciocutaneous island flap is reliable and very useful for covering defects over the distal leg, ankle, heel, foot, and Achilles tendon, especially in young children.

Feasibility of Ultrasound-Guided Percutaneous Placement of Peripheral Nerve Stimulation Electrodes in a Cadaver Model: Part One, Lower Extremity

Peripheral nerve stimulation (PNS) is analgesic for some lower extremity neuropathic pain syndromes. PNS currently involves open surgical placement of electrode(s). Increasingly, ultrasound guidance is used for perioperative neural block. Minimally invasive placement of PNS electrodes for lower extremity targets using ultrasound guidance has not been reported. We hypothesized that ultrasound-guided placement of PNS electrodes was feasible. Four cadaver mid-thigh transected fresh frozen specimens were studied. Specimens were scanned utilizing a 14 to 7 MHz linear probe and electrodes were placed proximal to the tibial, peroneal, and sciatic nerves at various locations. Anatomical dissection was performed to check placement accuracy and evaluate for grossly visible neural injuries. Acceptable locations for ultrasound-guided electrode placement were: (1) tibial nerve, approximately 8 to 14 cm superior to the medial malleolus above the tarsal tunnel, or at the upper popliteal fossa; (2) peroneal nerve, approximately 2 to 4 cm inferior to the lateral fibular head or at the upper popliteal fossa; (3) sciatic nerve immediately superior to the bifurcation (high popliteal area); and (4) lateral sural nerve at the lower popliteal fossa. No grossly visible neural injuries were seen. Electrode placements appeared to be in satisfactory locations for stimulation. Ultrasound imaging to facilitate peripheral nerve electrode placement is feasible. This new minimally invasive approach to lead placement requires further study to determine trial implantation criteria, optimal locations, anchoring techniques, and best clinical practice.

Endoscopically Assisted Sural Nerve Harvest in Infants

A technique of endoscopic sural nerve harvest was devised to minimize the donor site scarring in infants requiring peripheral nerve grafting procedures. The harvests were performed under tourniquet control using three 2-cm incisions for access at the lateral malleolus, midcalf, and popliteal fossa. Endoscopic visualization and blunt dissection of the nerve was achieved with a 4-mm-diameter, 18-cm-long telescope with a 0-degree angle lens, stabilized in an Emory retractor and attached to a video camera. The medial sural nerve was divided in the popliteal fossa proximally under direct vision. The lateral sural nerve was identified and harvested when present. This technique has been in use since 1994 and has been undertaken in more than 200 patients. The most common indication for surgery was obstetrical brachial plexus palsy. No nerve graft injury was noted upon examination under the operating microscope. Postoperative pain, swelling, and ecchymosis were minimal. Most patients have a detectable area of sensory loss at long-term follow-up but are unaware of this finding. Donor site scarring has been aesthetically satisfactory.

Effect of size and pressure of surface recording electrodes on amplitude of sensory nerve action potentials.

The influence of electrode size on sensory nerve action potential (SNAP) amplitude of the lateral antebrachial cutaneous nerve (LACN) and sural nerve (SN) was studied in 63 healthy volunteers. The SNAP amplitudes were measured using surface recording electrodes of three different sizes, positioned across the nerve. Mean amplitudes using a 5-mm electrode were 9.0% (SN) and 15.3% (LACN) higher than with a 20-mm electrode and 19.4% (SN) and 25.8% (LACN) higher than using a 40-mm electrode. To study the influence of pressure on surface recording electrodes, studies were performed on the LACN in 31 healthy volunteers. Light pressure of the recording electrodes on the skin gave lower amplitudes (15.3%) than did greater pressure or pressure applied between active and reference electrodes. These studies demonstrate that standardized surface recording electrode size and pressure are imperative for obtaining valid and reliable results in experimental studies or in clinical follow-up of patients undergoing nerve conduction studies.

Endoscopic sural nerve harvest in the pediatric patient.

A technique of endoscopic sural nerve harvest was devised to minimize the donor-site scarring in pediatric patients requiring peripheral nerve-grafting procedures. The harvests were performed under tourniquet control using two 2-cm incisions for access at the lateral malleolus and the midcalf. Endoscopic visualization and blunt dissection of the nerve were achieved with a 4-mm Hopkins telescope with 30-degree angled lens (Karl Storz GmbH, Tuttlingen, Germany) stabilized in an Emory retractor and attached to a video camera. The medial sural nerve was divided in the popliteal fossa proximally under endoscopic visualization. The lateral sural nerve was identified and harvested when present. Between June of 1994 and March of 1995, 18 patients underwent 27 sural nerve harvests using the endoscopic technique. Mean patient age was 3.3 years (range 4 to 197 months). Indications for surgery included obstetrical brachial plexus palsy (12), facial palsy (5), and ulnar nerve neuroma (1). Nerve-graft length harvested ranged from 13 to 41 cm. Mean tourniquet time per limb was 92 minutes. No nerve graft injury was noted on examination under the operating microscope. Postoperative pain, swelling, and ecchymosis were minimal. Donorsite scarring has been aesthetically satisfactory to date.

Variabilities of ipsi- or contralateral P40 dominancy in the lateral femoral cutaneous, tibial and sural nerve somatosensory evoked potentials

Variabilities of ipsi- or contralateral P40 dominancy in the lateral femoral cutaneous, tibial and sural nerve somatosensory evoked potentials

Clinical Implications of the Surgical Anatomy of the Sural Nerve

The exact anatomy of the sural nerve remains important for many clinical situations. To better understand this anatomy, 25 embalmed and 10 fresh cadaver pairs were studied. The origin of the common sural nerve in relation to the fibular head and its medial and lateral sural components were investigated. The lateral sural nerve was absent in 4 percent of the embalmed cadavers. The lateral and medial sural nerves united in the popliteal fossa in 12 percent and in the lower third of the leg in 84 percent of the cadavers. A site was identified where the lateral sural and lateral cutaneous nerve of the calf pierced the deep fascia. This site was centered about the fibular head and may be viewed as a potential site of nerve compression. There is application of these findings to nerve grafting, neuroma prevention and treatment, and sural nerve biopsy.

Topographical effects of transcutaneous electrical nerve stimulation on the H-reflex of the triceps surae muscles

The present study was conducted on eight normal subjects in order to evaluate the effects of transcutaneous electrical nerve stimulation (TENS); 99 Hz, 250 μs pulse duration, applied over either the common peroneal (CPN) or sural nerve, on the H-reflex of the soleus (SO), gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) muscles. Within each session, SO, GL and GM H-reflexes were recorded before (for 5 min), during (for 30 min) and after (for 10 min) TENS was applied at twice the sensory threshold for perception. It was found that, on average, while the stimulation was administered on the CPN: (a) the GL H-reflex amplitude increased by 40% (Friedman test: χ 2 = 11.71, P < 0.05); (b) the SO H-reflex decreased (≥ 10% H ctrl), although not in a statistically significant manner, in five of eight subjects; and (c) the GM H-reflex remained, overall, relatively stable. No significant effects of TENS over the sural nerve were found on any of the investigated muscles. The finding of increased H-reflex amplitudes in GL during TENS made it less likely that CPN stimulation had reciprocal inhibitory effects. However, such an increase could be attributed to a selective effect (such as a decrease in the recruitment threshold) on type II motoneurons of the GL. Furthermore, the topographical effects observed on the GL during TENS may reflect selective local effects due to stimulation of a sensory branch of the CPN, the lateral sural nerve, which mainly innervates the skin overlying the GL. The absence of effects noted on the GM during TENS further supports this hypothesis as the cutaneous afferents overlying that muscle were not stimulated. The repetitive cutaneous stimulation over the sural nerve, at the lateral malleolus, may have been too distal to stimulate the cutaneous receptors overlying the SO.

Lower leg reconstruction using a sural fasciocutaneous flap.

The fasciocutaneous flap in the lower leg has been widely used since Pontén's 1981 report. The cutaneous artery running along the sural nerve--known as the superficial sural artery--has an important role in the blood supply of the fasciocutaneous flap in the lower leg as stated by Haertsch. The superficial sural artery has great variation with regard to its location and the origin of the vessel. The cutaneous artery is intimately connected to the sural nerve or the lateral sural nerve. It may run along the sural nerve or along the lateral sural nerve. We examined this vessel in 10 cadaver dissections and applied it in 17 clinical cases of pedicled, island, and free flaps. The island sural fasciocutaneous flap is particularly versatile for the reconstruction of the soft tissue defect around the knee joint. The operative procedure involving the island fasciocutaneous flap and the characteristics of this sural fasciocutaneous flap are described.

The somatotopic organization of primary afferent terminals in the superficial laminae of the dorsal horn of the rat spinal cord.

Transganglionic transport of wheatgerm agglutinin conjugated horse-radish peroxidase (WGA-HRP) was used to reveal the central distribution of terminals of primary afferent fibers from peripheral nerves innervating the hind leg of the rat. In separate experiments the sizes and locations of cutaneous peripheral receptive fields were determined by electrophysiological recording techniques for each of the nerves that had been labeled with WGA-HRP. By using digital image analysis, the sizes and positions of the peripheral receptive fields were correlated with the areas of superficial dorsal horn occupied by terminals of primary afferents from each of these receptive fields. Data were obtained from the posterior cutaneous nerve of the thigh, lateral sural, sural, saphenous, superficial peroneal, and tibial nerves. The subdivisions of the sciatic nerve, the sural, lateral sural, superficial peroneal, and tibial nerves each projected to a separate and distinct region of the superficial dorsal horn and collectively formed a "U"-shaped zone of terminal labeling extending from lumbar spinal segments L2 to the caudal portions of L5. The gap in the "U" extended from L2 to the L3-4 boundary and was occupied by terminals from the saphenous nerve. Collectively, all primary afferents supplying the hindlimb occupied the medial 3/4 of the superficial dorsal horn with terminals from the tibial nerve lying most medially and occupying the largest of all the terminal fields. Afferents from the superficial peroneal lay in a zone between the medially situated tibial zone and the more laterally placed sural zone. Afferents from the posterior cutaneous nerve were located most caudally and laterally. Terminal fields from the posterior cutaneous and saphenous nerves differed from the others in having split representations caused presumably by their proximity to the mid-axial line of the limb. Comparisons between the peripheral and the central representations of each nerve revealed that 1 mm2 of surface area of the superficial dorsal horn serves approximately 600-900 mm2 of hairy skin and roughly 300 mm2 of glabrous skin. The vast majority of terminal labeling observed in the dorsal horn was found in the marginal layer and substantia gelatinosa, suggesting that small diameter afferents have an orderly somatotopic arrangement in which each portion of the skin surface is innervated by afferent fibers that terminate in preferred localities within the dorsal horn.