Lateral Sural Cutaneous Nerve Research Articles

A Cadaveric Study of Two Uncommon Cases of Sural Nerve Complex Variation

Abstract Introduction The sural nerve is a sensitive nerve whose function is to provide sensory supply for the posterolateral aspect of the distal third of the leg and the lateral side of the dorsum of the foot. This nerve is formed in the upper third of the calf from the terminal branches of the tibial and common peroneal nerves and the communicating branch of the sural nerve. Objectives The aim of our study is to showcase two anatomical variants of the sural nerve. Materials and methods Two formalin-preserved cadavers, one male and one female, embalmed using formalin 4% were dissected with the intent of being used as teaching materials for the students attending anatomy classes at the “George Emil Palade” University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, Romania. Results In both cases, less common anatomical variations of the formation of sural nerve were discovered. On the male cadaver, we identified the sural nerve as a continuation of the medial sural cutaneous nerve. The lateral sural cutaneous nerve and the communicating branch of the sural nerve were both absent. On the female cadaver, we identified both the medial sural cutaneous nerve and the lateral sural cutaneous nerve. The sural nerve was, however, a continuation of only the lateral sural cutaneous nerve, with the medial sural cutaneous nerve as an independent branch. Conclusions We described two anatomical variants of the sural nerve, which are less common than those documented in the literature.

N°360 – Lateral Sural Cutaneous Nerve Injury following Traumatic Femoral Fracture: A case report

N°360 – Lateral Sural Cutaneous Nerve Injury following Traumatic Femoral Fracture: A case report

Anatomical patterns of the sural nerve: a meta-analysis with clinical and surgical considerations.

The sural nerve (SN) supplies the posterolateral aspect of the leg and the lateral aspects of the ankle and foot and descends through the gastrocnemius muscle along the lower third of leg. Because in-depth knowledge about SN anatomy is essential for clinical and surgical approaches, our study aims to review SN anatomical patterns. We searched the PubMed, Lilacs, Web of Science, and SpringerLink databases to find relevant articles for meta-analysis. We assessed the quality of the studies using the Anatomical Quality Assessment tool. We used proportion meta-analysis to analyze the SN morphological variables and simple mean meta-analysis to analyze the SN morphometric variables (nerve length and distance to anatomical landmarks). Thirty-six studies comprised this meta-analysis. Overall, Type 2A (63.68% [95% CI 42.36-82.64]), Type 1A (51.17% [95% CI 33.16-69.04]) and Type 1B (32.19% [95% CI 17.83-48.38]) were the most common SN formation patterns. The lower third of leg (42.40% [95% CI 32.24-52.86]) and middle third of leg (40.00% [95% CI 25.21-53.48]) were the most common SN formation sites. The pooled SN length from nerve formation to the lateral malleolus was 144.54mm (95% CI 123.23-169.53) in adults, whereas the SN length was 25.10mm (95% CI 23.20-27.16) in fetuses in the second trimester of gestation and 34.88mm (95% CI 32.86-37.02) in fetuses in the third trimester of gestation. The most prevalent SN formation pattern was the union of the medial sural cutaneous nerve with the lateral sural cutaneous nerve. We found differences regarding geographical subgroup and subject age. The most common SN formation sites were the lower and middle thirds of the leg.

A Case of Recurrent Varices after Surgery (REVAS) of the Lateral Small Saphenous Vein Just Near the Lateral Sural Cutaneous Nerve Treated with Cyanoacrylate Closure

A Case of Recurrent Varices after Surgery (REVAS) of the Lateral Small Saphenous Vein Just Near the Lateral Sural Cutaneous Nerve Treated with Cyanoacrylate Closure

Clinical effects of free peroneal artery perforator flaps in repairing forefoot skin and soft tissue defect wounds assisted with three-dimensional computed tomography angiography

Objective: To investigate the clinical effects of free peroneal artery perforator flaps in repairing forefoot skin and soft tissue defect wounds assisted with three-dimensional computed tomography angiography (3D-CTA). Methods: A retrospective observational study was conducted. From March 2017 to September 2019, 15 patients with skin and soft tissue defect wounds in the forefoot were treated in the Department of Burn and Plastic Surgery of Yidu Central Hospital of Weifang, including 12 males and 3 females, with age of 18-60 years. The wound area on admission was 3.0 cm×3.0 cm-9.0 cm×8.0 cm. The 3D-CTA examination before operation was performed to select the peroneal artery perforating vessels with appropriate length of vascular pedicle and good blood perfusion. According to the wound area and the perforating vessels of the peroneal artery located by 3D-CTA, the peroneal artery perforator flaps of 3.5 cm×3.5 cm-9.5 cm×8.5 cm carried with lateral sural cutaneous nerve was designed and cut, and the nerve was anastomosed with the nerve of the wound. The wound in the donor site of the flap was directly sutured or covered with medium-thickness skin graft from the thigh. The consistencies of type, diameter, and perforating position of perforating vessel of the peroneal artery detected by 3D-CTA before the operation with those of the actual measurement during operation were observed. The length of time for flap cutting and the survival of the flap after operation were recorded. During follow-up of 12 months after the operation, the patients were instructed to evaluate the foot function according to the Maryland foot function score standard, and the wound healing in the donor area and the occurrence of complications affecting the motor function of limb were observed. Data were statistically analyzed with paired sample t test. Results: The types of peroneal artery perforating vessels in patients measured during the operation were septocutaneous perforator of 12 cases, musculocutaneous perforator of 2 cases, and musculomuscular septal perforator of 1 case, which were consistent with those measured by preoperative 3D-CTA. The diameter of the peroneal artery perforating vessel measured by preoperative 3D-CTA was (1.38±0.17) mm, which was close to (1.40±0.19) mm measured during the operation (t=0.30, P>0.05). The horizontal distance from the starting point of the perforating vessel to the outer edge of the shank was (42±6) mm, and the vertical distance from the starting point of the perforating vessel to the level of the lateral ankle tip was (219±14) mm measured by preoperative 3D-CTA, which were respectively close to (43±6) and (221±15) mm of intraoperative measurement (with t values of 0.46 and 0.38, respectively, P>0.05). The length of time for cutting flap was (31±6) min. All flaps survived post operation without vascular crisis. During follow-up of 12 months after the operation, the foot function was evaluated as excellent in 11 cases, good in 3 cases, and fair in 1 case, the donor site wound healed well, the scar was not noticeable with no contracture, and the motor function of joints was not affected. Conclusions: Free peroneal artery perforator flap is one of the effective methods to reconstruct skin and soft tissue defect wounds in the forefoot, and the risk of surgery can be reduced when the anatomical location of the perforating vessels is confirmed by 3D-CTA.

ID:16076 IPG-Free Peripheral Nerve Stimulation Bilateral Sural Nerves for Chronic Pain in Lower Extremities

The sural cutaneous nerve consists of the fusion of the medial sural cutaneous nerve, which is a terminal branch of the tibial nerve, and the lateral sural cutaneous nerve from the peroneal nerve. These two branches are connected by the sural communicating branch and form the sural nerve. The nerve courses subcutaneously from the mid posterior popliteal fossa to just posterior to the lateral malleolus. It supplies sensation to the skin of the lateral foot, calf, and lower ankle.

Фетальна топографія шкірних нервів гомілкової ділянки

The purpose of the study was to determine the topographic and anatomical relationships of the cutaneous nerves of the lower leg in human fetuses of 4-6 months. Materials and methods. The study was performed on 27 preparations of human fetuses of 81.0-230.0 mm parietal-coccygeal length, using the methods of macromicroscopic preparation and morphometry. Results and discussion. In most of the studied fetuses, there was a classic variant of innervation of the skin of the lower leg region, both on the right and left. In other fetuses, variability in the number and length of cutaneous nerves in the lower leg region was found. The most interesting, from our point of view, were the anatomical variants of innervation of the skin of the lower leg region in the fetuses of 90.0, 158.0, 182.0, and 190.0 mm parietal-coccygeal length. Taking into account the individual and age anatomy of the cutaneous nerves of the leg in human fetuses provides not only the scientific value of the results, but also the rational use of knowledge in the practice of traumatologists, anesthesiologists and surgeons. The study of variants of innervation of the skin of the lower leg region in human fetuses from the standpoint of modern macroscopic anatomy is considered relevant and promising. The need to clarify the topographic and anatomical features of the innervation of the skin of the lower leg region in human fetuses of different ages is due to the search for ways to prevent iatrogenic damage to the cutaneous nerves of the shin when performing surgical and anesthetic manipulations on the structures of this area, since the establishment of the anatomical variability of the skin nerves and branches allows to choose the optimal tactics of surgical intervention. In the literature, there are fragmentary data on the fetal topography of the cutaneous nerves of the lower leg region. Conclusion. In fetuses of 90.0 mm and 158.0 mm parietal-coccygeal length, the innervation of the skin of the anterior-upper surface of the lower leg region was provided by two cutaneous branches from the tibial nerve. In the fetus of 190.0 mm parietal-coccygeal length lateral sural cutaneous nerve was not involved in the formation of the sural nerve, the area of its innervation was limited to the proximal two-thirds of the tibia. Innervation of the lateral border of the foot and lateral bone, in this case, provided only the medial sural cutaneous nerve from the tibial nerve. In the fetus of 182.0 mm parietal-coccygeal length medial sural cutaneous branches are represented by a single independent nerve trunk, from which at different angles short sensitive branches began

Unusual presentation of lateral sural cutaneous nerve schwannoma: An exceptional case report

IntroductionSchwannoma is the most common benign nerve sheath tumor. Peripheral nerves of the lower extremity are rarely involved and usually asymptomatic.Case presentationWe report the case of a misleading clinical presentation of lateral sural cutaneous nerve schwannoma.DiscussionTo the best of our knowledge, no case has been reported about the location of schwannoma in the lateral sural cutaneous nerve. MRI and anatomopathologic assessment, after microscopic enucleation, are required to confirm diagnosis.ConclusionCare must be taken to not miss a schwannoma of lateral sural cutaneous nerve by meticulous clinical examination and appropriate imaging using MRI in unexplained L5 sciatica.

Anatomy of the sural nerve complex: Unaccounted anatomic variations and morphometric data

BackgroundThe sural nerve (SN) is a cutaneous sensory nerve innervating the posterolateral leg. The SN is formed from a highly variable set of contributing nerves called the sural nerve complex (SNC). The SNC is made up of the lateral sural cutaneous nerve, medial sural cutaneous nerve, sural communicating branch, and SN. The SN is frequently cited as the most common donor nerve graft and is commonly injured in procedures of the lower extremity. Recent meta-analysis standardized six morphologies of the SNC and established a required reporting criterion for the group of nerves forming the SN. Due to the inconsistencies in previous literature, this study will group observed SNC's by one of these six SNC morphologies to assess and validate the meta-analysis grouping criteria. This study will also collect the same morphometric data previously outlined in order to grow the number of samples that are reported in a standardized fashion. Methods100 formalin and 4 Theil preserved cadavers (n = 208) lower limbs were bilaterally dissected at Kansas City University and Creighton University School of Dentistry to observe the SNC in its entirety on the posterolateral leg. Anatomic data was captured utilizing the standardized morphologies types 1–6 with two sub-typing. Nerves that were found to be outside of this categorization were placed in an unassigned grouping. ResultsThe most prevalent SNCs were type 1 at 41.35% (n = 86) and type 3 nerves at 34.62% (n = 72). Type 2 was found 8.65% (n = 18), type 4 and 5 were found each at 0.48% (n = 1). Type 6 was not observed. When comparing the present studies frequency of nerve types 1–6 to the meta-analysis a sub-grouping of “North American” cadaveric studies a X2 = .903 p = .030 was found. Two distinct and previously unassigned formations of the SNC were 10.58% (n = 20) and 3.85% (n = 8) of data. These two SNC are termed type 7 & 8, these represent two formations of SN that are outside of what was previously reported. 15.87% (n = 33) did not match visual descriptions based on nerve origin of a type 1 SNC but met written definitions. These were termed type 1A1 and type 1A2. The SNC was asymmetrical in 57.69% (n = 120). The pooled mean length of the SN was 32.97 ± 14.12 cm (31.05–34.88), mean diameter was 2.31 ± 0.83 mm (2.20–2.42, and the distance of the posterior border of the lateral malleolus to the SN was found to be 1.72 ± 0.70 cm (1.63–1.80). ConclusionAnatomic variation in the SNC is highly variable, yet is consistent with previously observed literature. This study demonstrates two unaccounted formations of the SNC as well as two additional subcategories of SNC that were not included in the previous meta-analysis. These four variants warrant inclusion as standard formations of the SNC due to the high prevalence observed in this study as well as historical consistency observed in previous literature and case reports. These two SNC formations increase the risk of iatrogenic injury during surgical interventions of the lower extremity. Morphometric data describing the spatial relationship of this nerve complex on the posterolateral leg is consistent with previously reported data and aids in generating a large data set for future studies to characterize spatial properties of this nerve complex.

Fibular Nerve Repair by Lateral Sural Cutaneous Nerve Graft: Anatomic Feasibility Study and Clinical Results

The common fibular nerve (CFN) is the most frequently injured nerve in the lower limbs. Surgical management is necessary in approximately two thirds of patients and includes neurolysis, suture, graft repair, or nerve transfer. The distal sural nerve is the preferred donor for grafting, but it is not without complications and requires a second incision. We sought to study the surgical anatomy of the lateral sural cutaneous nerve (LSCN) with the aim of repairing CFN injuries through the same incision and as a potential source for grafting in other nerve injuries. The popliteal fossa was dissected in 11 lower limbs of embalmed cadavers to study LSCN variations. Four patients with CFN injuries then underwent surgical repair by LSCN grafting using the same surgical approach. At the medial margin of the biceps femoris, the LSCN emerged from the CFN approximately 8.15 cm above the fibular head. The LSCN ran longitudinally to the long axis of the popliteal fossa, with an average of 3.2 cm medial to the fibular head. The mean LSCN length and diameter were 9.61 cm and 3.6 mm, respectively. The LSCN could be harvested in all patients for grafting. The mean graft length was 4.4 cm. Motor function was consistently recovered for foot eversion but was recovered to a lesser extent for dorsiflexion and toe extension. All patients recovered sensitive function (75% of S3). Hypoesthesia was recognized at the calf. LSCN harvest is a viable alternative for nerve grafting, especially for repairing short CFN injuries, thereby avoiding the need for a second incision.

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.

Sihler's staining of the cutaneous nerves of the leg and its implications for sensory reconstruction.

This study aimed to reveal the entire cutaneous nerve distribution pattern of the leg and provide a morphological basis for sensory reconstruction during skin flap transplantation. Twelve adult cadavers were fixed with formalin, and the whole leg skin with subcutaneous fat was removed close to the muscle surface. The cutaneous nerves were visualized using modified Sihler's staining to reveal the distribution and innervation density of the cutaneous nerves. The saphenous nerve innervated the anterior part, 82.2% of the upper-middle region of the lateral part of the anterolateral leg, and the upper 63.4% of the medial posterior leg. The superficial peroneal nerve innervated 90.1% of the lateral lower one-third of the anterolateral leg. The medial sural cutaneous nerve covered 26.4% of the posterior leg. The lateral sural cutaneous nerve covered 42.3% (approximately 28.6% overlap with the saphenous nerve) of the upper-middle region of the anterolateral and posterolateral leg. The number of branches differed between certain cutaneous nerves in the leg. Communications were observed between the arborizations of the four cutaneous nerves mentioned above. The highest density of primary and secondary nerve branches was observed in the upper one-third of the lateral posterior leg. The upper one-third of the posteromedial leg contained the highest density of intracutaneous nerve branches and highest number of total nerve branches. These results may be used to map sensory regions when designing leg skin flaps for reconstruction surgery to obtain improved sensory recovery.

Analysis of the Sural Nerve Complex in North American Adult Cadavers: Distribution, Population Specific Morphology, and Anatomic Variants.

BACKGROUNDThe Sural nerve complex (SNC) consists of four components: the medial sural cutaneous nerve, lateral sural cutaneous nerve, sural communicating branch, and sural nerve proper. The sural nerve is a cutaneous nerve that innervates the distal posterolateral leg and dorsolateral foot. The SNC is highly variable and has six defined morphological types each representing different patterns in which the SNC can form the sural nerve proper. Because of variability amongst different populations the SNC may frequently become a site of iatrogenic injury.PURPOSEThe purpose of this study was to determine if the morphological type and spatial characteristics of the SNC we found in North Americans aligned with that described in the current literature.METHODSSix defined morphologic types of SNC have been described, each representing different patterns in which the SNC forms the sural nerve proper (Pirarvin, KR, Annals of Anatomy, 202, 36–44, 2015). Cadaveric data was obtained bilaterally in from 49 formalin‐ and three Thiel‐embalmed body donors (n=104 limbs) from KCUMB via superficial dissection methods revealing the SNC in the posterior leg. Measurements were obtained using forensic rules and calipers and documented using a digital camera. This study first approved by the KCUMB Institutional Biosafety Committee.RESULTSOur results showed a predominance of two major types of SNCs. In the first type (53%), the SNC originated from the lateral sural cutaneous nerve or common fibular cutaneous nerve. In the second type (34%), the SNC originated from the medial sural cutaneous nerve independent of the sural communicating branch, with or without the presence of lateral sural cutaneous nerve contribution. We also found a prevalence of bilateral asymmetry (67%) in the formation of the SNC. Lastly, were found higher frequencies of previously described SNC variants including connections of the SNC with the posterior femoral cutaneous nerve (30%) and terminal branches of the medial sural cutaneous nerve connecting with other cutaneous nerves adjacent the lateral malleolus (22%).CONCLUSIONOur data showed there are two prevalent forms of SNCs within the North American population and that bilateral asymmetry is more common than previously reported. A more complete understanding of the variation in the SNC is important for clinical electrophysiology evaluations, neurological disease testing, lower extremity tissue repair, and sural nerve use in autogenous nerve grafts.

Branching Patterns and Anatomical Course of the Common Fibular Nerve.

ObjectiveTo present the branching patterns and anatomical course of the common fibular nerve (CFN) and its relationship with fibular head (FH).MethodsA total of 21 limbs from 12 fresh cadavers were dissected. The FH width (FH_width), distance between the FH and CFN (FH_CFN), and thickness of the nerve were measured. The ratio of the FH_CFN to FH_width was calculated as follows: <1, cross type and ≥1, posterior type. Angle between the CFN and vertical line of the lower limb 5 cm proximal to the tip of the FH was measured. Branching patterns of the lateral cutaneous nerve of the calf (LCNC) were classified into four types according to its origin and direction as follows: type 1a, lateral margin of the CFN; type 1b, medial margin of the CFN; type 2, lateral sural cutaneous nerve (LSCN); and type 3, CFN and LSCN.ResultsIn the cross type (15 cases, 71.4%), the ratio of FH_CFN/FH_width was 0.83 and the angle was 13.0°. In the posterior type (6 cases, 28.6%), the ratio was 1.04 and the angle was 11.0°. In the branching patterns of LCNC, type 2 was the most common (10 cases), followed by types 1a and 1b (both, 5 cases).ConclusionLocation of the CFN around the FH might be related to the development of its neuropathy, especially in the cross type of CFN. The LCNC showed various branching patterns and direction, which could be associated with difficulties of electrophysiologic testing.

Unusual anatomical variation in formation of sural nerve

Background: Sural nerve is formed by communication of medial sural cutaneous nerve, that arise from tibial nerve in popliteal fossa and peroneal communicating nerve, a branch directly from common peroneal nerve or from lateral sural cutaneous nerve.The objective of this study was described an unusual and few reported anatomical variation in formation of sural nerve.&#x0D; Materials and Methods: The anatomical variation described was found during routine dissection performed by medical students of second semester in two maleembalbed adult cadavers of 75 and 65 years of age, respectivelyin the laboratory of Morphology of the University of Pamplona.&#x0D; Results and Discussion: In the left lower limb, both medial sural cutaneous nerve, and lateral sural cutaneous nervewere absent. The sural nerve arose directly from the tibial nerve. It’s observed a communicating branch between tibial nerve and common peroneal nerve. In the right lower limb, lateral sural cutaneous nerve was absent. The sural nerve arose directly from the common peroneal nerve.Peroneal communicating nerve was considered as absent in the two cases.Motor fiber from sural nerve to gastrocnemius muscle was observed in both lower limbs&#x0D; Conclusions:The knowledge of the sural nerve (normal anatomy and variations in origin and course) is important in evaluating of the patients, as well explaining the different clinical findings necessary for accuracy treatment.&#x0D; Bangladesh Journal of Medical Science Vol.18(3) 2019 p.508-512

Natural Sensations Evoked in Distal Extremities Using Surface Electrical Stimulation.

Background Electrical stimulation is increasingly relevant in a variety of medical treatments. In this study, surface electrical stimulation was evaluated as a method to non-invasively target a neural function, specifically natural sensation in the distal limbs. Method Electrodes were placed over the median and ulnar nerves at the elbow and the common peroneal and lateral sural cutaneous nerves at the knee. Strength-duration curves for sensation were compared between nerves. The location, modality, and intensity of each sensation were also analyzed. In an effort to evoke natural sensations, several patterned waveforms were evaluated. Results Distal sensation was obtained in all but one of the 48 nerves tested in able-bodied subjects and in the two nerves from subjects with an amputation. Increasing the pulse amplitude of the stimulus caused an increase in the area and magnitude of the sensation in a majority of subjects. A low frequency waveform evoked a tapping or tapping-like sensation in 29 out of the 31 able-bodied subjects and a sensation that could be considered natural in two subjects with an amputation. This waveform performed better than other patterned waveforms that had proven effective during implanted extra-neural stimulation. Conclusion Surface electrical stimulation has the potential to be a powerful, non-invasive tool for activation of the nervous system. These results suggest that a tapping sensation in the distal extremity can be evoked in most able-bodied individuals and that targeting the nerve trunk from the surface is a valid method to evoke sensation in the phantom limb of individuals with an amputation for short term applications.

Anatomical variations of the formation of human sural nerve in stillborns

IntroductionThe sural nerve (SN) is formed by the union of the medial and lateral sural cutaneous nerves (MSCN, LSCN) of the leg that originate from the tibial and common peroneal nerves. Sural nerve is used for various reasons in surgical operations. The sural nerve is universally recognized by surgeons as a site for harvesting an autologous nerve graft The aim of this study was to describe the course, variations, morphometric analysis and some clinically significant relations of the human sural nerve in stillborns. MethodsThe study was carried out on 18 Turkish stillborns, 12 males and 6 females. The formation of sural nevre was classified into three main groups. The site of formation of the sural nerve was observed and the length of the sural nerve components were measured. ResultsThree types of SN formation were observed. Type A (anastomotic type) was seen in 33 of the observed 36 legs (92%). The site of formation of the SN by union of the MSCN and LSCN was 30% (10/33). In males, the mean length of MSCN was 24.59±14.84mm and 27.45±23.30mm in females. DiscussionThis study was performed to ensure an anatomical and morphometrical description of the sural nerve and its components in 18 embalmed stillborns. Due to its great importance in neurosurgery and plastic surgery, the formation type, course and formation level of the sural nerve have been studied on different races and age groups since the beginning of the last century.

Natural Sensations Evoked in Distal Extremities Using Surface Electrical Stimulation

Background:Electrical stimulation is increasingly relevant in a variety of medical treatments. In this study, surface electrical stimulation was evaluated as a method to non-invasively target a neural function, specifically natural sensation in the distal limbs.Method:Electrodes were placed over the median and ulnar nerves at the elbow and the common peroneal and lateral sural cutaneous nerves at the knee. Strength-duration curves for sensation were compared between nerves. The location, modality, and intensity of each sensation were also analyzed. In an effort to evoke natural sensations, several patterned waveforms were evaluated.Results:Distal sensation was obtained in all but one of the 48 nerves tested in able-bodied subjects and in the two nerves from subjects with an amputation. Increasing the pulse amplitude of the stimulus caused an increase in the area and magnitude of the sensation in a majority of subjects. A low frequency waveform evoked a tapping or tapping-like sensation in 29 out of the 31 able-bodied subjects and a sensation that could be considered natural in two subjects with an amputation. This waveform performed better than other patterned waveforms that had proven effective during implanted extra-neural stimulation.Conclusion:Surface electrical stimulation has the potential to be a powerful, non-invasive tool for activation of the nervous system. These results suggest that a tapping sensation in the distal extremity can be evoked in most able-bodied individuals and that targeting the nerve trunk from the surface is a valid method to evoke sensation in the phantom limb of individuals with an amputation for short term applications.

Sural Nerve Splitting in Reverse Sural Artery Perforator Flap: Anatomical Study in 40 Cadaver Legs.

The reverse sural artery perforator flap has been widely used in reconstruction of the lower extremity. However, along with the high rate of flap necrosis, sural nerve injury is one of the most frequent complications. This cadaveric study investigated a simple sural nerve preservation technique during reverse sural artery perforator flap surgery. Cadaver dissection was performed on 40 cadaver lower legs, to investigate the pattern of sural nerve distribution. The points where the lateral and medial sural cutaneous nerves penetrate the deep fascia were measured. The converging point of these nerves into the sural nerve was also recorded. Furthermore, the sural nerve was split until no tethering was observed, to simulate the sural nerve-sparing reverse sural artery perforator flap. Twenty-nine legs (72.5 percent) showed the lateral and medial sural cutaneous nerves converging to become the sural nerve (combined pattern); seven (17.5 percent) and four legs (10.0 percent) demonstrated the diminished and parallel types, respectively. The distances between the lateral malleolus and the fascia-penetrating point of the lateral and medial sural cutaneous nerves were 29.9 ± 3.3 cm and 18.8 ± 5.6 cm, respectively. In the combined type, the point of convergence was 13.6 ± 4.2 cm from the lateral malleolus. Nerve splitting was successfully performed in all combined cases, without injuring the nerve fascicles. The medial sural cutaneous nerve enters the deep fascia significantly more distally than does the lateral sural cutaneous nerve. Furthermore, using nerve splitting, the medial sural cutaneous nerve can be kept intact during reverse sural artery perforator flap surgery.

Estudo dos nervos do membro pélvico do Tamandua tetradactyla / Study of the nerves of the pelvic limb of Tamandua tetradactyla

O objetivo deste estudo foi descrever a distribuição dos nervos do membro pélvico do T. tetradactyla. Para tanto, foram utilizados quatro cadáveres de animais adultos cedidos pelo IBAMA-GO. Cada animal teve o membro pélvico de ambos os antímeros dissecados após fixação em solução de formaldeído a 10%. Os nervos genitofemoral e cutâneo femoral lateral distribuíram-se na pele medial e craniomedial e craniolateral da coxa, respectivamente. O nervo femoral emitiu ramos para os músculos psoas menor, iliopsoas, sartório e pectíneo; terminando por penetrar no músculo quadríceps femoral. Emitiu o nervo safeno, que em seu trajeto, inervou a pele da face medial da coxa e perna e região dorsomedial do pé. O nervo obturador emitiu ramos para músculos mediais da coxa. Os nervos glúteos cranial e caudal inervaram a musculatura glútea. O nervo isquiático inervou os músculos gêmeos, quadrado femoral, semimembranoso, semitendinoso, bíceps femoral longo e curto e terminou dividindo-se nos nervos cutâneo lateral da sura, tibial, e fibular comum. O nervo cutâneo lateral da sura inerva a região cutânea craniolateral do joelho e perna, enquanto os nervos fibular comum e tibial inerva a musculatura da perna e terminam distribuindo-se no pé.