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Ultrasound examination of femoral, saphenous and lateral cutaneousfemoral nerves was performed in 25 healthy volunteers(50 extremities) with normal body weight, at mean age374.3 years. Examination procedure and topography of theinvestigated nerves are described. The nerves identification ispossible due to anatomical landmarks. Femoral and lateralfemoral cutaneous nerves were visualized in all cases. Cutaneousnerves are available for proper visualization in subjects with normallydeveloped subcutaneous fat. Structural features of nervesdidnt show statistically significant sexual and bilateral distinctions.Sonography is an accessible method for examination ofcertain lumbar plexus nerves.

Meralgia paresthetica is a neuropathy of the lateral femoral cutaneous nerve. Traditionally, the diagnosis is based on classical symptoms and signs. In cases where there is a diagnostic dilemma, the role of magnetic resonance imaging has been to exclude other causes for the patient’s presentation, as the small extraspinal peripheral nerves were not well visualised at imaging. The development of 3-Tesla magnetic resonance neurography, however, has made pathology of these nerves more conspicuous.

Introduction: Subcutaneous internal fixation (InFix) has become a valid alternative for anterior fixation of pelvic ring injuries. Complications associated with this technique are lateral femoral cutaneous nerve (LFCN) irritation and anterior thigh pain due to prominent implants. The aim of this study was to identify a configuration of the InFix that causes the least adverse side effects.Methods: Nineteen patients (6 females, mean age 61 years) with 38 hemipelves were included. Rod-to-bone distance and symphysis-rod distance were measured on AP- and outlet- radiographs. These distances were analyzed in relation to the primary outcomes: early removal of the InFix, post-operative complications and damage of the LFCN.Results: Regarding rod-to-bone distance, a distance of 20 to 25 mm causes less complications, LFCN damage and no early removals of the InFix. Symphysis-to-rod distance analysis showed the best results regarding LFCN damage and other complications when the rod had a distance of less than 40 mm to the symphysis. A distance more than 40 mm was associated with fewer early removal of the InFix.Conclusions: Planned optimized configuration of the InFix with a rod-to-bone distance between 20 and 25 mm may reduce postoperative complications. Regarding LFCN damage, the rod-to-symphysis distance should not be more than 40 mm. [ABSTRACT FROM AUTHOR]

• Electrophysiological methods have limited value in the diagnosis of MP. • Level of the inguinal ligament is the most vulnerable segment in the MP. • More distal or more proximal segments of LFCN may also be involved. • Segmental analysis of NCS of LFCN may help lesion localisation in the MP. A common entrapment site of the lateral femoral cutaneous nerve (LFCN) is in the vicinity of the inguinal ligament. However the more distal segment of this nerve can also be affected. Electrophysiological evaluation of this nerve is difficult. Additionally, available methods have failed in the lesion localization of LFCN. In this study, we aimed to evaluate nerve conduction study in different segments of the LFCN. Nerve action potentials of the LFCN were recorded with distal surface electrodes from a relatively distant point (about 30 cm caudal to the spina iliaca anterior superior). An electrical stimulus was given both 10 cm distal to the SIAS and at the level of the SIAS. Inguinal segmental and distal sensory nerve conduction studies were performed on the LFCN. Thirty-eight healthy controls and 34 patients with meralgia paresthetica (MP) were analyzed by this method. All patients with MP showed electrophysiological abnormalities. Slowed sensory conduction on the inguinal channel (p:0.0001) and loss of response were the most frequent abnormalities (44.7% and 31.6%). In one patient, the only abnormality was slowed sensory conduction at the distal site. Our findings suggest that this technique can help in diagnosis and lesion localization in MP. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective To trace anatomic variations of the lateral femoral cutaneous nerve (LFCN) in its intrapelvic course. Methods Forty cadavers (80 sides) fixed in 10% formalin solution were dissected. The following parameters were recorded: LFCN diameter and variations in its origin and number. The dissection comprised exposure and excision of the lumbar plexus, together with the roots of LFCN, followed by retrograde intraneural fascicular dissection using microsurgical instruments. Results Several types of LFCN origin from the lumbar plexus were observed. Typically, the LFCN appears as a single trunk arising from dorsal divisions of the ventral rami of the lumbar plexus. The most prevalent origin of the nerve was from the L2 and L3 roots (47 cases; 58.75%). The LFCN took an origin from the L1-L2 level in 12 cases (15%) and from the L2 nerve in 9 cases (11.25%). The main observed variations were the presence of the accessory LFCN (2 cases; 2.5%) and branching of the LFCN from the femoral nerve (6 cases; 7.5%). Communications between the LFCN and the femoral or genitofemoral nerves also were observed occasionally. An atypical course of the LFCN with respect to the anterior psoas was observed in our material in 3 of the 80 sides (3.75% of the examined LFCN specimens). Conclusions Considerable variability in the origin and the course of the LFCN was observed, which should be taken into account during clinical assessment of nerve lesions and during surgery via transpsoas approaches to the lumbar spine. Highlights • Various origins of the lateral femoral cutaneous nerve (LFCN) from the lumbar plexus were observed. • The main variations were the presence of an accessory LFCN and branching of the LFCN from the femoral nerve. • Communications between the LFCN and surrounding nerves were traced by retrograde intraneural fascicular dissection. • The location of the LFCN within the psoas major muscle was examined. [ABSTRACT FROM AUTHOR]

Meralgia paresthetica (MP) is a sensory mononeuropathy of the lateral femoral cutaneous nerve (LFCN). MP has rarely been reported after a femoral intervention approach. We report a case of bilateral meralgia paresthetica following bilateral femoral cannulation. A 64-year-old male received cardiac catheterization and treatment via a bilateral femoral vein. After cardiac catheterization, the patient presented with paresthesia in the anterolateral aspect of the bilateral thigh. After performing nerve conduction studies and electromyography, he was diagnosed as MP. Although a bilateral LFCN lesion following a femoral approach is very rare, MP might require caution regarding potential variations in LFCN when performing the femoral approach.

Although anterior subcutaneous pelvic internal fixation is a valuable tool for the reduction and fixation of unstable pelvic ring injuries, lateral femoral cutaneous nerve irritation by the implant is the most common complication. This study aimed to investigate the association between the nerve-to-implant distance and the postoperative lateral femoral cutaneous nerve symptom. Patients who underwent anterior subcutaneous pelvic internal fixation between 2016 and 2019 were retrospectively analyzed. Lateral femoral cutaneous nerve status was defined as follows: not identified, nerve-to-implant distance <13 mm, and ≥13 mm. The proportion of patients who experienced postoperative nerve disorders was compared using the nerve status. Nerve-to-implant distances were compared using the presence or absence of postoperative lateral femoral cutaneous nerve disorders. The predictive value of a nerve-to-implant distance of 13 mm for postoperative nerve disorders was assessed. Overall, 26 lateral femoral cutaneous nerves were included. Ten patients had postoperative nerve disorders, of which seven had an nerve-to-implant distance <13 mm, while the other three occurred in patients whose nerves were not identified. A nerve-to-implant distance ≥13 mm was significantly associated with a decreased risk of postoperative nerve disorder compared to a nerve-to-implant distance <13 mm (p = 0.017). A nerve-to-implant distance ≥13 mm had a perfect sensitivity (100%) and modest specificity (58.3%). Nerve-to-implant distance was ≥13 mm. Nerve disorders were frequently observed when the nerve-to-implant distance was <13 mm or the nerve was not identified intraoperatively. Efforts to identify the lateral femoral cutaneous nerve may be useful to avoid internal fixation-related nerve disorders., Competing Interests: None.

Abstract We present an unusual case of sartorius muscle tear presenting as acute meralgia paresthetica. A healthy 67-year old male was referred to our department with a one-week history of pain, numbness and bruising over his hip and anterolateral thigh. Extended ultrasound assessment revealed an intramuscular tear of sartorius, with acute hematoma surrounding the adjacent lateral femoral cutaneous nerve. Meralgia paresthetica from acute trauma is rare, with only three published cases relating to fractures of the anterior superior iliac spine. To our knowledge, this is the first case caused by muscular tear in the literature. The presence of features attributable to neuropraxia of the lateral femoral cutaneous nerve allowed for proper localization and diagnosis of the patient's injury. [ABSTRACT FROM AUTHOR]

Meralgia paresthetica ( MP) is an entrapment neuropathy of the lateral femoral cutaneous nerve ( LFCN). There are many variations in the course of the LFCN. A 55-year-old woman presented with pain and tingling sensations on the anterolateral aspect of her left thigh. Physical examination revealed hypoesthesia of the proximal anterolateral thigh on the left side. During the electrodiagnostic study, sensory nerve action potential of the LFCN could not be obtained on both sides. Through those clinical and electrophysiological findings, we prediagnosed the case as MP and planned to perform diagnostic nerve block. For the injection to perform, ultrasonography was used. During the ultrasonographic evaluation, the left LFCN was visualized lateral to the anterior superior iliac spine ( ASIS). Then ultrasound-guided nerve block with 2 cc lidocaine 2% for diagnostic purpose was performed in this region. Immediately after the injection, the patient's complaints relieved completely, and hence the patient was diagnosed as having MP with an LFCN anatomical variation. Two months later her complaints persisted, and ultrasound-guided LFCN injection with 2 mL of lidocaine 2% + 1 cc of betametazone was performed. One month after the second injection, her complaints were relieved markedly and she resumed her daily activities. In conclusion, the course of the LFCN is quite variable. We present a relatively rare anatomical variation of the LFCN, crossing lateral to the ASIS, diagnosed with ultrasonography. Ultrasonography can be performed to visualize the LFCN, especially a nerve with an anatomical variation. [ABSTRACT FROM AUTHOR]

Objective: Established subcutaneous internal fixation techniques have shown better outcomes but still have significant complications, like injury of the lateral femoral cutaneous nerve (LFCN). A novel modified technique, the Bridging Infix, has been proposed to aid in the reduction of complications. The at-risk anatomical structures for the procedure are unknown. Therefore, the study aims to determine the relationship between the Bridging Infix and neighboring structures. Methods: A total of fifty formalin-fixed cadaveric specimens (n=50) and two fresh frozen cadaver specimens (n=2) were utilized (Ethical clearance: 182/2021). Any cadavers with evidence of previous pelvic or abdominal surgery, pathology or damage were excluded. The Bridging Infix was placed by surgeons as per the technique guide. Superficial and deep dissections were completed and measurements of the distance between adjacent structures and the implant as well as bony landmarks were taken to determine safe zones. Results: The mean distance from the most medial implant screw to the LFCN was 37.97 mm (SD: 12.20). The iliohypogastric nerve was the closest structure to the rod-to-rod connector with a minimum distance of 5.40 mm and 3.14 mm on the left and right, respectively. The ilioinguinal nerve was a minimum distance of 12.36 mm on the left and 7.12 mm on the right. Conclusion: The Bridging Infix has shown no damage to important adjacent anatomical structures. Thus, the surgical procedure can be considered safe if the screws are directly inserted into the iliac crest and no pressure is applied within three finger breaths from the anterior superior iliac spine or pubic tubercle along the inguinal ligament. [ABSTRACT FROM AUTHOR]