Active nerve management for above the knee amputation: A comparison of through the wound versus posterior approach.

Targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI) are used to prevent or treat neuromas in amputees. TMR for above-the-knee amputation (AKA) is most commonly performed through a posterior incision rather than the stump wound because recipient motor nerves are primarily located in the proximal third of the thigh. When preventative TMR is performed with concurrent AKA, a posterior approach requires intraoperative repositioning and an additional incision. The purpose of this study was to evaluate feasibility of TMR and operative times for nerve management performed through the wound compared to a posterior approach in AKA patients to guide surgical decision-making. Patients who underwent AKA with TMR between 2018-2023 were reviewed. Patients were divided into two groups: TMR performed through the wound (Group I) and TMR performed through a posterior approach (Group II). If a nerve was unable to undergo coaptation for TMR due to the lack of suitable donor motor nerves, RPNI was performed. Eighteen patients underwent AKA with nerve management were included from Group I (8 patients) and Group II (10 patients). TMR coaptations performed on distinct nerves was 1.5 ± 0.5 in Group I compared to 2.6 ± 0.5 in Group II (p = 0.001). Operative time for Group I was 200.7 ± 33.4 min compared to 326.5 ± 37.1 min in Group II (p = 0.001). TMR performed through the wound following AKA requires less operative time than a posterior approach. However, since recipient motor nerves are not consistently found near the stump, RPNI may be required with TMR whereas the posterior approach allows for more TMR coaptations.

Innervated vastus lateralis muscle: complementing and completing the anterolateral thigh flap for abdominal wall reconstruction.

Reconstruction of composite abdominal wall defects is challenging. An anterolateral thigh (ALT) flap has established itself in the algorithm for abdominal wall reconstruction. Augmenting innervated vastus lateralis (iVL) muscle to ALT has added advantages. We describe previously unreported advantage of ALT with iVL.A woman in her 30s, suffering from Mullerian adenocarcinoma with metastasis to the right anterior abdominal wall and right inguinal lymph node, was taken for wide local excision and reconstruction. After excision, there was a 15×12 cm defect of the anterior abdominal wall. We reconstructed the defect with prosthetic mesh and pedicled composite ALT and iVL. There was venous congestion in the ALT flap and it could not be salvaged. We debrided the ALT flap and applied split skin graft over iVL. The grafted and donor sites healed well. The patient was able to do moderate strenuous activities. The presence of iVL allowed us to get away with minor procedure and averted the need for another flap.

Distal subsartorial compartment block of the saphenous nerve - A dissection study and a patient case series.

STUDY OBJECTIVE: A saphenous nerve block is an important tool for analgesia after foot and ankle surgery. The conventional midthigh approach to saphenous nerve block in the femoral triangle may impede ambulation by impairing quadriceps motor function. PRIMARY OBJECTIVE: Developing a selective saphenous nerve block targeting the nerve distal to its emergence from the adductor canal in the subsartorial compartment. DESIGN: This study consists of A) a dissection study and B) Data from a clinical case series. SETTING: A) Medical University of Innsbruck, Austria (dissection of 15 cadaver sides) and. B) Aarhus University Hospital, Denmark (5 patients). INTERVENTIONS: A) Five mL of methylene blue was injected into the subsartorial compartment distal to the intersection of the saphenous nerve and the tendon of the adductor magnus guided by ultrasound. B) Five patients undergoing major hindfoot and ankle surgery had a subsartorial compartment block with 10 mL of local anesthetic in addition to a popliteal sciatic nerve block. MEASUREMENT: A) The frequencies of staining the saphenous and medial vastus nerves. B) Assessment of postoperative pain by NRS score (0-10) and success rate of saphenous nerve block by presence of cutaneous anesthesia in the anteromedial lower leg, and motor impairment by ability to ambulate. MAIN RESULTS: A) The saphenous nerve was stained in 15/15 cadaver sides. A terminal branch of the medial vastus nerve was stained in 2/15 cadaver sides. B) All patients were fully able to ambulate without support. No patients had any post-surgical pain from the anteromedial aspect of the ankle and foot (NRS score 0). The success rate of saphenous nerve block was 100%. CONCLUSION: The saphenous nerve can be targeted in the subsartorial compartment distal to the intersection of the nerve and the tendon of the adductor magnus. The subsartorial compartment block provided efficient analgesia without quadriceps motor impairment.

Conventional versus lateral fasciotomy for prevention of lateral femoral cutaneous nerve injury in the non-fan-type nerve in total hip arthroplasty with direct anterior approach.

Aims: Lateral femoral cutaneous nerve (LFCN) injury is a potential complication after the direct anterior approach for total hip arthroplasty (DAA-THA). The aim of this study was to determine how the location of the fasciotomy in DAA-THA affects LFCN injury. Methods: In this trial, 134 patients were randomized into a lateral fasciotomy (n = 67) or a conventional fasciotomy (n = 67) group. This study was a dual-centre, double-blind, prospective randomized controlled two-arm trial with parallel group design and a 1:1 allocation ratio. The primary endpoint was the presence of LFCN injury, which was determined by the presence of numbness, decreased sensation, tingling, jolt-like sensation, or pain over the lateral aspect of the thigh, excluding the surgical scar, using a patient-based questionnaire. The secondary endpoints were patient-reported outcome measures (PROMs) using the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), and the Forgotten Joint Score-12 (FJS-12). Assessments were obtained three months after surgery. Results: The incidence of LFCN injury tended to be lower in the lateral fasciotomy group (p = 0.089). In the lateral fasciotomy group, there were no significant differences in the mean PROM scores between patients with and without LFCN injury (FJS-12: 54.42 (SD 15.77) vs 65.06 (SD 26.14); p = 0.074; JHEQ: 55.21 (SD 12.10) vs 59.72 (SD 16.50); p = 0.288; WOMAC: 82.45 (SD 6.84) vs 84.40 (SD 17.91); p = 0.728). In the conventional fasciotomy group, there were significant differences in FJS-12 and JHEQ between patients with and without LFCN injury (FJS-12: 43.21 (SD 23.08) vs 67.28 (SD 20.47); p < 0.001; JHEQ: 49.52 (SD 13.97) vs 59.59 (SD 15.18); p = 0.012); however, there was no significant difference in WOMAC (76.63 (SD 16.81) vs 84.16 (SD 15.94); p = 0.107). Conclusion: The incidence of LFCN injury at three months after THA was comparable between the lateral and conventional fasciotomy groups. Further studies are needed to assess the long-term effects of these approaches.

Meralgia Paresthetica: Relevance, Diagnosis, and Treatment.

BACKGROUND: Pain and sensory disturbance in the distribution of the lateral femoral cutaneous nerve in the ventrolateral portion of the thigh is called meralgia paresthetica (MP). The incidence of MP has risen along with the increasing prevalence of obesity and diabetes mellitus and was recently estimated at 32 new cases per 100 000 persons per year. In this review, we provide an overview of current standards and developments in the diagnosis and treatment of MP. METHODS: This review is based on publications retrieved by a selective literature search, with special attention to meta-analyses, systematic reviews, randomized and controlled trials (RCTs), and prospective observational studies. RESULTS: The diagnosis is mainly based on typical symptoms combined with a positive response to an infiltration procedure. In atypical cases, electrophysiological testing, neurosonography, and magnetic resonance imaging can be helpful in establishing the diagnosis. The literature search did not reveal any studies of high quality. Four prospective observational studies with small case numbers and partly inconsistent results are available. In a meta-analysis of 149 cases, pain relief was described after infiltration in 85% of cases and after surgery in 80%, with 1-38 months of follow-up. In another meta-analysis of 670 cases, there was pain relief after infiltration in 22% of cases, after surgical decompression in 63%, and after neurectomy in 85%. Hardly any data are available on more recent treatment options, such as radiofrequency therapy, spinal cord stimulation, or peripheral nerve stimulation. CONCLUSION: The state of the evidence is limited in both quantity and quality, corresponding to evidence level 2a for surgical and non-surgical methods. Advances in imaging and neurophysiological testing have made the diagnosis easier to establish. When intervention is needed, good success rates have been achieved with surgery (decompression, neurectomy), and variable success rates with infiltration.

Unusual causes for meralgia paresthetica: systematic review of the literature and single center experience.

Meralgia paresthetica is often idiopathic, but sometimes symptoms may be caused by traumatic injury to the lateral femoral cutaneous nerve (LFCN) or compression of this nerve by a mass lesion. In this article the literature is reviewed on unusual causes for meralgia paresthetica, including different types of traumatic injury and compression of the LFCN by mass lesions. In addition, the experience from our center with the surgical treatment of unusual causes of meralgia paresthetica is presented. A PubMed search was performed on unusual causes for meralgia paresthetica. Specific attention was paid to factors that may have predisposed to LFCN injury and clues that may have pointed at a mass lesion. Moreover, our own database on all surgically treated cases of meralgia paresthetica between April 2014 and September 2022 was reviewed to identify unusual causes for meralgia paresthetica. A total of 66 articles was identified that reported results on unusual causes for meralgia paresthetica: 37 on traumatic injuries of the LFCN and 29 on compression of the LFCN by mass lesions. Most frequent cause of traumatic injury in the literature was iatrogenic, including different procedures around the anterior superior iliac spine, intra-abdominal procedures and positioning for surgery. In our own surgical database of 187 cases, there were 14 cases of traumatic LFCN injury and 4 cases in which symptoms were related to a mass lesion. It is important to consider traumatic causes or compression by a mass lesion in patients that present with meralgia paresthetica.

Lateral versus conventional fasciotomy for prevention of lateral femoral cutaneous nerve injury in total hip arthroplasty with direct anterior approach: a study protocol for a dual-center, double-blind, randomized controlled trial.

BACKGROUND: An incision for total hip arthroplasty (THA) via the direct anterior approach (DAA) is generally made outside of the space between the sartorius and tensor fasciae latae muscles to prevent lateral femoral cutaneous nerve (LFCN) injury. Anatomical studies have revealed that the LFCN courses between the sartorius and tensor fasciae latae muscles. When the LFCN branches radially while distributing in the transverse direction from the sartorius muscle to the tensor fasciae latae muscle, it is called the fan type. Studies suggest that damage to the fan type LFCN is unavoidable during conventional fasciotomy. We previously demonstrated that injury to non-fan variation LFCN occurred in 28.6% of patients who underwent THA by fasciotomy performed 2 cm away from the intermuscular space. This suggests that the conventional approach also poses a risk of LFCN injury to non-fan variation LFCN. LFCN injury is rarely reported in the anterolateral approach, which involves incision of fascia further away than the DAA. The purpose of this study is to investigate how the position of fasciotomy in DAA affects the risk of LFCN injury. METHODS: We will conduct a prospective, randomized, controlled study. All patients will be divided into a fan variation and a non-fan variation group using ultrasonography before surgery. Patients with non-fan variation LFCN will receive conventional fasciotomy and lateral fasciotomy in the order specified in the allocation table created in advance by our clinical trial center. The primary endpoint will be the presence of LFCN injury during an outpatient visit using a patient-based questionnaire. The secondary endpoints will be assessed based on patient-reported outcomes at 3 months after surgery in an outpatient setting using the Western Ontario and McMaster Universities Osteoarthritis Index, the Japanese Orthopaedic Association Hip-disease Evaluation Questionnaire, and the Forgotten-Joint Score-12. DISCUSSION: We hypothesize that the incidence of LFCN injury due to DAA-THA is reduced by making the incision further away from where it is typically made in conventional fasciotomy. If our hypothesis is confirmed, it will reduce the disadvantages of DAA and improve patient satisfaction. TRIAL REGISTRATION: UMIN Clinical Trials Registry, UMIN000035945 . Registered on 20 February, 2019.

Anatomical Analysis of the Lateral Femoral Cutaneous Nerve and Its Passage beneath the Inguinal Ligament.

BACKGROUND: Meralgia paraesthetica is a mononeuropathy of the lateral femoral cutaneous nerve. According to the literature, the nerve travels beneath the inguinal ligament 1.3 to 5.1 cm medial to the anterior superior iliac spine. Compression at this site may cause pain and paresthesia. The aim of this study was to provide more accurate measurements to improve the diagnostic and surgical management of meralgia paraesthetica. METHODS: The lateral femoral cutaneous nerve was dissected bilaterally in 50 Thiel-embalmed human cadavers. Measurements were performed with a standard caliper at the superior and inferior margins of the inguinal ligament. The distance from the inner lamina of the anterior superior iliac spine to the medial margin of the lateral femoral cutaneous nerve was measured. Data were collected and statistical analysis was performed with R. RESULTS: Ninety-three lateral femoral cutaneous nerves of 50 cadavers were dissected. In 6 percent of cadavers, the lateral femoral cutaneous nerve could not be found. The mean distance from the inner lamina of the anterior superior iliac spine to the lateral femoral cutaneous nerve's medial border was 2.1 ± 1.3 cm (range, 0.2 to 6.4 cm; 95 percent CI, 1.8 to 2.4 cm) at the superior margin of the inguinal ligament and 1.9 ± 1.4 cm (range, 0.2 to 3.0 cm; 95 percent CI, 1.6 to 2.2 cm) at the inferior border of the inguinal ligament. CONCLUSION: This anatomical study shows that the majority of the lateral femoral cutaneous nerve passes beneath the inguinal ligament in a very narrow area of 0.6 cm.

Saphenous nerve schwannoma as a cause of vascular claudication - case report and review of the literature.

Schwannomas are peripheral nerve tumours that are uncommon. They typical present with a palpable mass, pain or neurological changes. We describe a saphenous nerve schwannoma compressing the superficial femoral artery and causing vascular claudication. We also review the literature.

Sensory Recovery of the Breast following Innervated and Noninnervated Lateral Thigh Perforator Flap Breast Reconstruction.

BACKGROUND: The lateral thigh perforator flap, based on the tissue of the upper lateral thigh, is an excellent option for autologous breast reconstruction. The aim of this study was to introduce the technique to perform a nerve coaptation in lateral thigh perforator flap breast reconstruction and to analyze the results by comparing the sensory recovery of the reconstructed breast and donor site between innervated and noninnervated lateral thigh perforator flaps. METHODS: A prospective cohort study was conducted of patients who underwent an innervated or noninnervated lateral thigh perforator flap breast reconstruction between December of 2014 and August of 2018. Direct nerve coaptation was performed between a branch of the lateral femoral cutaneous nerve and the anterior cutaneous branch of the intercostal nerve. Sensory testing was performed with Semmes-Weinstein monofilaments to assess the sensation of the native skin, flap skin, and donor site during follow-up. RESULTS: In total, 24 patients with 37 innervated lateral thigh perforator flaps and 18 patients with 26 noninnervated lateral thigh perforator flaps were analyzed (median follow-up, 17 and 15 months, respectively). Significantly lower mean monofilament values were found for the native skin (adjusted difference, -0.83; p = 0.011) and flap skin (adjusted difference, -1.11; p < 0.001) of the reconstructed breast in innervated compared to noninnervated flaps. For the donor site, no statistically significant differences were found between both groups. CONCLUSIONS: Nerve coaptation in lateral thigh perforator flap breast reconstruction resulted in a significantly better sensory recovery of the reconstructed breast compared to noninnervated flaps. The data also suggest that harvesting a sensory nerve branch does not compromise the sensory recovery of the upper lateral thigh.

Natural history of lateral femoral cutaneous nerve neuropraxia after anterior approach total hip arthroplasty.

AIM:: The aim of this study was to examine the natural history of lateral femoral cutaneous nerve (LFCN) neuropraxia in a previously reported cohort of individuals after direct anterior approach (DAA). METHODS:: 99 patients (107 hips) with LFCN neuropraxia were identified, out of which 82 patients (87 hips) (83.1%) completed functional outcomes questionnaires at mean follow-up of 5.5 years (4.4-6.9 years). 5 patients were excluded from the study due to intra-articular source of pain and/or revision surgery. The total sample was composed of 77 patients (31 total hip replacements and 51 hip resurfacings) and functional outcomes scores were obtained for all patients. RESULTS:: At average 5.46-year follow-up, 55 patients (60 hips 73%) still reported symptoms of LFCN neuropraxia but their Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were not inferior to those who had resolution for pain, function and stiffness: p values of 0.716, 0.171, and 0.238, respectively. The mean score on visual analogue scale decreased from 2.32 (SD 2.11) to 1.76 (SD 1.99). 1 patient (1.2%) reported his activities were limited by his symptoms. CONCLUSION:: Although the majority of patients still report symptoms related to LFCN neuropraxia, symptoms do improve over time and there are no functional limitations. Even if LFCN neuropraxia following DAA does not lead to functional limitations, all patients should be made aware in order to alleviate any long-term functional concerns.

Surgical options for meralgia paresthetica: long-term outcomes in 13 cases.

BACKGROUND: Meralgia paresthetica is an entrapment neuropathy of the lateral femoral cutaneous nerve that may cause paresthesias, pain, and sensory loss of the anterior and lateral thigh. Treatment is primarily medical. Surgery is an option for patients who do not respond to medical treatments. METHODS: Patients whose symptoms did not improve after medical and conservative treatment for at least 3 months were included in this study. These patients underwent neurolysis and decompression surgery and had a mean postoperative follow-up of 38 months. Their pain levels were assessed by the VAS scoring system. RESULTS: In 8 (61.5%) patients, the symptoms completely resolved within the first 3 months. In 5 (38.5%) patients, the complaints persisted partially and the recovery was observed after 12 months. In patients having a metabolic etiology, the duration of recovery was up to 12 months. CONCLUSION: The long term results of surgery are good though only partial improvemnts in reported pain were seen in the early postoperative period, especially in patients with a metabolic etiology.

Localization of the nerve entry points of thigh adductor muscles by spiral computed tomography: a novel anatomical guide for chemical neurolysis in treating muscle spasticity / Localización de los puntos de entrada del nervio de los músculos aductores del muslo mediante tomografía computarizada espiral: una nueva guía anatómica para la neurolosis química en el tratamiento de la espasticidad muscular

The nerve entry points (NEPs) cannot yet be accurately localized for the treatment of thigh adductor muscles spasticity in chemical neurolysis. The aim of this study was to identify the location and depth of the NEPs of thigh adductor muscles by spiral computed tomography (CT) and bony landmarks. Forty lower limbs of twenty adult cadavers were dissected in supine position. A curved line on skin surface from the tip of greater trochanter of femur to the center of pubic tubercle was designated as the horizontal reference line (H). Another curved line from the tip of great trochanter to the lateral epicondyle of femur was designated as the longitudinal reference line (L). Following dissection, the NEPs were labeled with barium sulfate, and their body surface projection points (P) were determined by spiral CT. Projection of NEP in the opposite direction was designated as P'. The percentage location of the intersections (PH and PL) of P with the H and L and the percentage depth of NEPs were determined with the Syngo system. The PH for the NEP of pectineus, gracilis, adductor longus, adductor brevis and adductor magnus muscles branch were located at 76.41±0.71 %, 93.85±2.07 %, 92.05±2.15 %, 80.75±1.20 % and 88.08±1.09 % of the H, respectively. The PLwere at 1.64±0.04 %, 29.89±1.90 %, 16.06±1.32 %, 11.66±0.11 % and 22.94±0.90 % of the L, respectively. The depth of NEP from P points were at 17.52±0.52 %, 38.38±2.75 %, 20.88±0.79 %, 20.35±0.82 % and 39.52±0.67 % of PP', respectively. These results help to carry out more precise localization of the NEPs. It should provide a novel anatomical guide for improving the efficacy and efficiency of chemical neurolysis in treating thigh adductor muscle spasticity.

Aún no se pueden localizar con precisión los puntos de entrada del nervio (PEN) para el tratamiento de la espasticidad de los músculos aductores del muslo a través de la neurólisis química. El objetivo de este estudio fue identificar la ubicación y la profundidad de los PEN de los músculos aductores del muslo mediante tomografía computarizada espiral (TC) y puntos de referencia óseos. Se disecaron loa miembros inferiores de 20 cadáveres adultos en posición supina. Se trazó una línea curva en la superficie de la piel desdeel ápice del trocánter mayor del fémur hasta el centro del tubérculo púbico y se designó como línea de referencia horizontal (H). Otra línea curva desde el ápice del trocánter mayor hasta el epicóndilo lateral del fémur se designó como línea de referencia longitudinal (L). Después de la disección, los PEN se marcaron con sulfato de bario y sus puntos de proyección de la superficie del cuerpo (P) se determinaron mediante TC helicoidal. La proyección de PEN en la dirección opuesta se designó como P '. El porcentaje de ubicación de las intersecciones (PH y PL) de P con H y L y la profundidad porcentual de los PEN se determinaron con el sistema Syngo. Los PH para los PEN de los músculos pectineus, gracilis, adductor longus, aductor brevis y rama aductora del músculo aductor magnus se localizaron en 76,41±0,71 %, 93,85±2,07 %, 92,05±2,15 %, 80,75±1,20 % y 88,08±1,09 % de H, respectivamente. Los PL estuvieron en 1,64±0,04 %, 29,89±1,90 %, 16,06±1,32 %, 11,66±0,11 % y 22,94±0,90 % de la L, respectivamente. La profundidad de PEN de P puntos fue de 17,52±0,52 %, 38,38±2,75 %, 20,88±0,79 %, 20,35±0,82 % y 39,52±0,67 % de PP ', respectivamente. Estos resultados ayudan a realizar una localización más precisa de los PEN. Se debe proponer una nueva guía anatómica para mejorar la eficacia y la eficiencia de la neurólisis química en el tratamiento de la espasticidad del músculo aductor del muslo.

Anatomy of the Pudendal Nerve and Other Neural Structures Around the Proximal Hamstring Origin in Males.

PURPOSE: To define the anatomy of the pudendal nerve in relationship to the proximal hamstring and other nearby neurological structures during proximal hamstring repair. METHODS: Six fresh-frozen human cadaveric hemi-pelvises from male patients ages 64.0 ± 4.1 years were dissected in prone position with hips in 10° flexion to identify the relationship of proximal hamstring origin to surrounding neurologic structures including the pudendal nerve, sciatic nerve, and posterior femoral cutaneous nerve. Two independent observers used digital calipers to measure distances. RESULTS: The pudendal nerve emerged at the inferior border of the piriformis muscle 6.3 ± 1.4 cm from the superior aspect of the proximal hamstring origin. It passed the superior border of the sacrotuberous ligament 3.0 ± 0.6 cm from the superior aspect and 3.9 ± 0.7 cm from the medial aspect of the hamstring origin. It crossed the inferior border of the sacrotuberous ligament 3.0 ± 0.4 cm from the superior aspect and 2.7 ± 0.7 cm from the medial aspect of the proximal hamstring origin. The shortest distance from the hamstring origin to the pudendal nerve was 2.6 ± 0.5 cm from the superior aspect and 2.3 ± 0.8 cm from the medial aspect. The shortest distance from the hamstring origin to the pudendal nerve was located deep to the sacrotuberous ligament in all cadavers. The sciatic nerve was an average of 1.1 ± 0.1 cm lateral to the lateral aspect of the proximal hamstring origin. The posterior femoral cutaneous nerve was located between the hamstring origin and the sciatic nerve, 0.7 ± 0.2 cm lateral to the lateral aspect of the proximal hamstring origin. CONCLUSIONS: The proximal hamstring origin lies in close proximity to surrounding nerves, including the pudendal, sciatic, and posterior femoral cutaneous nerves. CLINICAL RELEVANCE: Knowledge that the pudendal nerve lies 2 to 3 cm superior and medial to the proximal hamstring origin may help to prevent iatrogenic damage during surgical dissection and retraction when performing proximal hamstring repair or deep gluteal space endoscopy.

What Is the Risk Posed to the Lateral Femoral Cutaneous Nerve During the Use of the Anterior Portal of Supine Hip Arthroscopy and the Minimally Invasive Anterior Approach for Total Hip Arthroplasty?

PURPOSE: To determine: (1) What is the proximity of the lateral femoral cutaneous nerve (LFCN) to the anterior portal (AP) used in supine hip arthroscopy? (2) What is the proximity of the LCFN to the incision in the minimally invasive anterior approach (MIAA) for total hip arthroplasty? (3) What effect does lateralizing the AP have on the likelihood of nerve injury? (4) What branching patterns are observable in the LFCN? METHODS: Forty-five hemipelves were dissected. The LFCN was identified and its path dissected. The positions of the nerve in relation to the AP and the MIAA incision were measured. RESULTS: The AP intersected with 38% of nerves. In the remainder, the LFCN was located 5.7 ± 4.5 mm from the portal's edge. In addition, 44% of nerves crossed the incision of the MIAA. Of those that did not, the average minimum distance from the incision was 14.4 ± 7.0 mm. We found a significant reduction in risk if the AP is moved medially by 5 mm or laterally by 15 mm (P = .0054 and P = .0002). The LFCN showed considerable variation with 4 branching variants. CONCLUSIONS: These results show that the LFCN is at high risk during supine hip arthroscopy and the MIAA, emphasizing the need for meticulous dissection. We suggest that relocation of the AP 5 mm medially or 15 mm laterally will reduce the risk to the LFCN. CLINICAL RELEVANCE: These findings should aid surgeons in minimizing the risk to the LCFN during hip arthroscopy and the minimally invasive anterior approach to the hip.

The anatomy of the perineal branch of the sciatic nerve.

A "perineal" branch of the sciatic nerve has been visualized during surgery, but there is currently no description of this nerve branch in the literature. Our study investigates the presence and frequency of occurrence of perineal innervation by the sciatic nerve and characterizes its anatomy in the posterior thigh. Fifteen cadavers were obtained for dissection. Descriptive results were recorded and analyzed statistically. Twenty-one sciatic nerves were adequately anatomically preserved. Six sciatic nerves contained a perineal branch. Five sciatic nerves had a branch contributing to the perineal branch of the posterior femoral cutaneous (PFC) nerve. In specimens with adequate anatomical preservation, the perineal branch of the sciatic nerve passed posterior to the ischial tuberosity in three specimens and posterior to the conjoint tendon of the long head of biceps femoris and semitendinosus muscles (conjoint tendon) in one. In specimens in which the perineal branch of the PFC nerve received a contribution from the sciatic nerve, the branch passed posterior to the sacrotuberous ligament in one case and posterior to the conjoint tendon in three. Unilateral nerve anatomy was found to be a poor predictor of contralateral anatomy (Cohen's kappa = 0.06). Our study demonstrates for the first time the presence and frequency of occurrence of the perineal branch of the sciatic nerve and a sciatic contribution to the perineal branch of the PFC nerve. Clinicians should be cognizant of this nerve and its varying anatomy so their practice is better informed. Clin. Anat. 31:357-363, 2018. © 2018 Wiley Periodicals, Inc.

A rare presentation of meralgia paraesthetica in limb girdle muscular dystrophy.

A 44-year-old female with paraesthesia and pain on the left anterolateral thigh who had been diagnosed with limb-girdle muscular dystrophy by electromyography and muscle biopsy is presented. Neurological examination revealed atrophy of the proximal muscles of both shoulders, plus pseudo hypertrophy of both calves. Electromyography exhibited a myopathic pattern. Musculoskeletal ultrasound imaging demonstrated a fusiform nerve swelling below the inguinal ligament suggesting lateral femoral cutaneous nerve compression, consistent with meralgia paraesthetica. Treatment with a perineural injection of betamethasone dipropionate and betamethasone sodium phosphate combination, and prilocaine-HCl, under ultrasound guidance, was performed. Symptoms resolved within 6 h. At 3-week follow-up, the patient was asymptomatic, and there was no paraesthesia or pain on examination. In this case, ultrasound-guided perineural injection of the lateral femoral cutaneous nerve with local anaesthetics and steroid served both diagnostic and therapeutic functions.