Técnicas de neuroconducción del nervio femorocutáneo lateral / Nerve conduction techniques of femoral cutaneous nerve

El femorocutáneo lateral es un nervio exclusivamente sensitivo que se origina en las raíces lumbares altas, recorre la pelvis y finalmente pasa por debajo del ligamento inguinal hasta llegar al muslo, inervando su cara lateral. En la presente revisión, en primer lugar se describe la anatomía del nervio femorocutáneo lateral y las variantes anatómicas relevantes para los electromiografistas; en segundo lugar se hace un recuento de la diferentes técnicas de neuroconducción para activarlo y sus valores normales, y, finalmente, en tercer lugar se hacen otras consideraciones importantes con respecto a dichas técnicas.

The lateral femoral cutaneous is an exclusively sensitive nerve that originates in the upper lumbar roots, runs through the pelvis, and finally passes under the inguinal ligament until it reaches the thigh, innervating its lateral aspect. Firstly, the present review describes the anatomy of the lateral femoral cutaneous nerve and the anatomical variants re-levant to electromyographers. Secondly, the different nerve conduction techniques and their normal values are counted to obtain it; and thirdly, other important considerations are made regarding said techniques.

Prevalence and management of refractory meralgia paresthetica in lumbar spine surgery: 5 years of experience / Prevalência e manejo da meralgia parestésica refratária em cirurgia de coluna lombar: experiência de cinco anos / Prevalencia y manejo de la meralgia parestésica refractaria en cirugía de columna lumbar: experiencia de 5 años

ABSTRACT Objective The objective of our study was to report 5 years of experience in the recognition and management of refractory meralgia paresthetica (MP) in patients who had undergone posterior approach lumbar surgery. Methods Patients who were submitted to procedures in the lumbar spine from January 2010 to January 2015 in three different hospital centers in Belo Horizonte/MG were selected for an evaluation of the postoperative development of MP. A prospective observational comparative case series study. Level of evidence III. Evaluation of the following parameters: type of support for the patient, surgical time, body mass index. Results 367 posterior approach lumbar spine surgeries for degenerative pathologies of the lumbar spine were performed. MP was observed in 81 patients (22%). In 65 of those patients (80%), there was complete resolution of the symptoms with conservative management (local measures and medications for neuropathic pain) in less than two months. Twelve patients improved with a corticosteroid depot injection in the inguinal ligament and four patients required a surgical procedure in the third month. Pneumatic support was the least involved in the development of MP, as well as surgical time <1h and body mass index <25. Conclusion Refractory MP may occur in patients submitted to posterior approach lumbar spine surgeries. Management includes local measures, medications for neuropathic pain, and corticosteroid injection in the inguinal ligament. Decompression surgery is reserved for rare refractory cases. Level of evidence III; Prospective observational study with comparative case series.

RESUMO Objetivo O objetivo do presente estudo consiste em relatar a experiência de cinco anos no reconhecimento e manejo da meralgia parestésica (MP) refratária em pacientes submetidos a cirurgias lombares por via posterior. Métodos Pacientes submetidos a procedimentos na coluna lombar, no período de janeiro de 2010 a janeiro de 2015, em três diferentes centros hospitalares de Belo Horizonte/MG, foram selecionados para avaliação do desenvolvimento da MP pós-operatória. Estudo prospectivo observacional com série de casos comparativos. Nível III de evidência. Avaliação dos seguintes parâmetros: tipo de suporte para o paciente, tempo de cirurgia, índice de massa corporal. Resultados Foram feitas 367 cirurgias por via posterior da coluna lombar para patologias degenerativas da coluna lombar. A MP foi observada em 81 pacientes (22%). Em 65 pacientes (80%), houve resolução completa dos sintomas com manejo conservador (medidas locais e medicamentos para dor neuropática) em menos de dois meses. Doze pacientes melhoraram através de infiltração com corticoide de depósito e anestésico no local no ligamento inguinal e, em quatro pacientes houve necessidade de procedimento cirúrgico no terceiro mês. O suporte pneumático foi o menos envolvido no desenvolvimento da MP, assim como o tempo cirúrgico <1h e índice de massa corporal <25. Conclusão A MP refratária pode ocorrer em pacientes submetidos a cirurgias na coluna lombar por via posterior. O manejo inclui medidas locais, medicamentos para dor neuropática e infiltração com corticoide no ligamento inguinal. A cirurgia descompressiva está reservada para os raros casos refratários. Nível de evidência III; Estudo prospectivo observacional com série de casos comparativos.

RESUMEN Objetivo El objetivo del presente estudio consiste en relatar la experiencia de 5 años en el reconocimiento y manejo de la meralgia parestésica (MP) refractaria en pacientes sometidos a cirugías lumbares por vía posterior. Métodos Pacientes sometidos a procedimientos en la columna lumbar, en el período de enero de 2010 a enero de 2015, en tres diferentes centros hospitalarios de Belo Horizonte/MG, fueron seleccionados para evaluación del desarrollo de la MP postoperatoria. Estudio prospectivo observacional con serie de casos comparativos. Nivel III de evidencia. Evaluación de los siguientes parámetros: tipo de soporte para el paciente, tiempo de cirugía, índice de masa corporal. Resultados Se realizaron 367 cirugías por vía posterior de la columna lumbar para patologías degenerativas de la columna lumbar. La MP fue observada en 81 pacientes (22%). En 65 pacientes (80%) hubo resolución completa de los síntomas con manejo conservador (medidas locales y medicamentos para el dolor neuropático) en menos de 2 meses. Doce pacientes mejoraron a través de infiltración de corticoide de depósito y anestésico en el local en el ligamento inguinal y, en cuatro pacientes, hubo necesidad de procedimiento quirúrgico en el tercer mes. El soporte neumático fue el menos involucrado en el desarrollo de la MP, así como el tiempo quirúrgico <1h e índice de masa corporal <25. Conclusión La MP refractaria puede ocurrir en pacientes sometidos a cirugías en la columna lumbar por vía posterior. El manejo incluye medidas locales, medicamentos para el dolor neuropático e infiltración con corticoide en el ligamento inguinal. La cirugía descompresiva está reservada para los raros casos refractarios. Nivel de evidencia III; Estudio prospectivo observacional con serie de casos comparativos.

Anatomical and ultrasound observation of the nearby of the anterior superior iliac spine: the lateral femoral cutaneous nerve / 解剖学报

Objective Meralgia paresthetica(MP) is commonly caused by mechanical entrapment of the lateral femoral cutaneous nerve (LFCN). The entrapment often occurs at the site where the nerve exits the pelvis. Its optimal surgical management remains to be established, partly because the fine architecture of the fascial planes around the lateral femoral cutaneous nerve has not been elucidated. The purpose of this study is to determine the fascia structure of lateral femoral cutaneous nerve nearby the anterior superior iliac spine using anatomy and ultrasound technique. Methods Eleven cadavers were selected for plastination (6 female, 5 male, age range 38-97 years). Ultrasonography was performed on 34 healthy volunteers (19 women, 15 men, age range, 20-62 years). Results The lateral femoral cutaneous nerve exited the pelvis via a tendinous canal within the internal oblique-iliac fascia septum,and then between the sartorius muscle surface and the tensor fascia lata muscle located below the anterior superior iliac spine (ASIS). and then ran between the sartorius muscle and the tensor fascia. Conclusion Lateral femoral cutaneous nerve is located in the aponeurosis of the intra-abdominal oblique muscle at the pelvic outlet. Lateral femoral cutaneous nerve travels on the surface and outside of the sartorius muscle. These two segments of lateral femoral cutaneous nerve can be localized by ultrasound scans.

Meralgia parestésica: Lesión nerviosa posoperatoria, una responsabilidad compartida. Caso clínico y revisión bibliográfica / Meralgia paresthetic: Postoperative nerve injury, a shared responsibility. Clinical case and review

INTRODUCTION: Perioperative nerve injuries are of great concern to anesthesiologists. Meralgia paresthetica is a syndrome of pain and paresthesia in the anterolateral region of thigh caused by injury of the lateral femoral cutaneous nerve. The purpose of this paper is present a case, review the bibliography to determine management guidelines. METHOD: A search about paresthetic meralgia was conducted from December 2013 to March 2018, using the PubMed database. RESULT: Nerve injuries and particular meralgia paresthetica are entities with multiple risk factors for their development. The diagnosis can be very complex, requires a high index of suspicion and an adequate differential study of other processes. Its treatment can be conservative or surgical. In the exposed case there is also an investigation about the responsibilities associated with the operative procedure. CONCLUSION: Perioperative nerve injuries occur frequently, being a cause of morbidity, increased costs and medical legal implications of great relevance to anesthesiologists.

INTRODUCCIÓN: Las lesiones nerviosas perioperatorias son causa de gran preocupación para los anestesiólogos. La meralgia parestésica es un síndrome de dolor y parestesia en la región anterolateral del muslo originada por la lesión del nervio femorocutáneo lateral. El propósito de este trabajo es presentar un caso, revisar la bibliografía para determinar directrices de manejo. MÉTODO: Se presenta un caso clínico. Se realiza una búsqueda sobre la meralgia parestésica desde diciembre de 2013 a marzo de 2018, usando la base de PubMed. RESULTADO: Las lesiones nerviosas y en particular la meralgia parestésica son entidades con múltiples factores de riesgo para su desarrollo. El diagnóstico puede ser muy complejo, precisa un alto índice de sospecha y un adecuado estudio diferencial de otros procesos. Su tratamiento puede ser conservador o quirúrgico. En el caso expuesto además existe investigación sobre las responsabilidades asociadas al procedimiento operatorio. CONCLUSIÓN: Las lesiones nerviosas perioperatorias ocurren frecuentemente, siendo una causa de morbilidad, incremento de costos e implicaciones medicolegales de gran relevancia para los anestesiólogos.

Evaluation Of The Origin Variability Of The Lateral Femoral Cutaneous Nerve With Clinical Significance

Background and Objectives: The lateral femoral cutaneous nerve (LFCN) of the thigh arises from the dorsalbranches of the second and third lumbar ventral rami. Several variations in the formation, course and branchesof this nerve have been reported. The regional anatomy of the lateral femoral cutaneous nerve is highly variedand may account for its susceptibility to local trauma. Knowledge of these variations is important for surgeonsto avoid injury to the nerve. The aim of this study was to evaluate the variations in the formation of LFCN of thethigh and to discuss its clinical implications.Materials And Methods: The study was conducted on 25(50 sides) adult human cadavers in the Department ofAnatomy, Sri Siddhartha Medical College, Tumkur, Karnataka, India by dissection method. The LFCN was lookedfor, bilaterally, and its formation studied. The specimens were numbered and photographed.Results: In the present study, the lateral femoral cutaneous nerve of thigh arising from dorsal divisions of L2 L3was observed in 34(68%) specimens. Variations in LFCN were observed in 16 specimens. The variationsencountered were the absence of LFCN (2%), the origin of LFCN from ventral ramus of L1 spinal nerve (2%), theorigin of LFCN from ventral rami of L1 L2 spinal nerves (8%), the origin of LFCN as a branch of femoral nerve (20%).Conclusion: The present study highlights the necessity for a thorough knowledge of the topographical features ofthe LFCN so as to increase the efficacy of diagnosis, reduce complications and increase patient comfort.

Extended duration pulsed radiofrequency for the management of refractory meralgia paresthetica: a series of five cases

Meralgia paresthetica (MP) is a sensory mononeuropathy, caused by compression of the lateral femoral cutaneous nerve (LFCN) of thigh. Patients refractory to conservative management are treated with various interventional procedures. We report the first use of extended duration (8 minutes) pulsed radiofrequency of the LFCN in a case series of five patients with refractory MP. Four patients had follow up for 1–2 years, and one had 6 months follow up. All patients reported remarkable and long lasting symptom relief and an increase in daily life activities. Three patients came off medications and two patients required minimal doses of neuropathic medications. No complications were observed.

An Unusual Case of Bilateral Meralgia Paresthetica Following Femoral Cannulations / 신경중재치료의학

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.

Concurrent meralgia paresthetica and radiculopathy of the left leg: A case report

Meralgia paresthetica (MP) is a painful mononeuropathy of the lateral femoral cutaneouse nerve (LFCN) characterized by localized symptoms of numbness, tingling, pain and paresthesia along the anterolateral thigh area. L4 and L5 radiculopathy is set of symptoms that include sharp, burning or shooting pain, which is usually localized to anterolateral leg area and along the dermatomal distribution. When symptoms of MP and lumbar disc disease occur together it is not easy to diagnose MP. We report a case of synchronous post-traumatic MP and radiculopathy due to intervertebral disc herniation at L3–4 and 4–5. A 59-year-old male patient was admitted to the emergency room with symptoms of low back pain with left severe L4, L5 radiculopathy. This patient also complained of numbness and paresthesia in the left anterolateral thigh. After detailed history taking and lateral femoral cutaneouse nerve block, he was diagnosed with MP.

Utilidad de la neurografía por IRM en el diagnóstico de la meralgia parestésica / Usefulness of MRI neurography in the diagnosis of meralgia paresthetica

Objetivo: Evidenciar cómo la Imagen Resonancia magnética (IRM) con equipo de 3 Tesla, utilizando secuencias neurográficas específicas y uso de contraste endovenoso permite ubicar el área de lesión nerviosa. Caso clínico: Mujer de 17 años con hipoestesia y parestesias en la región anterior y lateral del muslo izquierdo, se le realiza un estudio de Resonancia Magnética (RM) en equipo Philips Achieva 3 T, usando protocolo neurográfico y contraste endovenoso, demostrando engrosamiento y cambios de señal del nervio y realce post-contraste característico de la neuropraxia. Conclusión: el caso presentado demuestra el valor actual de los estudios de IRM con técnica neurográfica en la evaluación de la patología de los nervios periféricos. Es fundamental utilizar secuencias adecuadas, realizar un estudio comparativo bilateral y en lo posible usar medios de contraste endovenoso para aumentar la sensibilidad. Estos hallazgos resultan de gran importancia a la hora de planificar la estrategia quirúrgica.

Objective: Demonstrate the usefulness of Magnetic Resonance Imaging (MRI) with equipment 3 Tesla using neurographics specific sequences and use of intravenous contrast can locate the area of nerve injury.Clinical case: 17 year old woman with hypoesthesia and paresthesia in the anterior and lateral region of the left thigh, the study of Magnetic Resonance Imaging (MRI) equipment Philips Achieva 3 T, using neurographic protocol and intravenous contrast, showing thickening and changes signal nerve and post-contrast enhancement characteristic in neuropraxia.Conclusión: the case presented shows the current value of MRI studies with neurographics technique in assessing the pathology of peripheral nerves. It is essential to use appropriate sequences, make a bilateral comparative study and possible use of intravenous contrast media to increase sensitivity. These findings are of great importance when planning the surgical strategy.

Meralgia Paresthetica Resulting from Inaccurate Wearing of a Thoraco-lumbo-sacral-orthosis / 계명의대학술지

Meralgia paresthetica is a lateral femoral cutaneous neuropathy that results in symptoms of anterolateral thigh paresthesia and numbness. Its presentation due to compression of a thoraco-lumbo-sacral-orthosis (TLSO) has not been reported. We experienced a case of a 67-year-old woman who developed left lateral femoral cutaneous neuropathy as a complication of inaccurate wearing of a TLSO. The patient suffered from tingling sensation and pain in the anterolateral aspect of the left thigh without muscular weakness. An electrodiagnostic study revealed a conduction block in the left lateral femoral cutaneous nerve (LFCN) around the inguinal ligament. Ultrasonography revealed swelling of the left LFCN compared with the right side. The patient's symptoms improved after she ceased wearing the TLSO and received conservative care. Considering the complications can develop after wearing spinal orthosis, we suggest that orthosis be prescribed accurately and inspected meticulously by experts physician.

Clinical and Electrophysiological Characteristics of Meralgia Paresthetica / 대한임상신경생리학회지

BACKGROUND: Meralgia paresthetica (MP) is a mononeuropathy affecting the lateral femoral cutaneous nerve. The disease is often diagnosed clinically, but electrophysiological tests play an important role. The aim of this study is to clarify clinical characteristics of MP as well as the role of sensory nerve conduction study (NCS) in the diagnosis of MP. METHODS: Sixty-five consecutive patients with clinical diagnosis of MP between March 2001 and June 2012 were retrospectively reviewed at a single tertiary center. General demographics, clinical characteristics and sensory NCS findings were investigated. Measurements of sensory NCS included the baseline-to-peak amplitude, side-to-side amplitude ratio and the conduction velocity. To compare between the normal and abnormal NCS groups, independent t-tests and chi-square test were performed. RESULTS: Sixty-five patients had male predominance (56.9%) with mean age of 48.4+/-13.4 years (range: 16-75). Seven patients (13.5%) had undergone operation or procedure before the symptom onset. The sensory nerve action potentials were obtainable in 52 (80%) of 65 clinically diagnosed MP patients. Sensory NCS revealed abnormalities in 38 patients (73.1%), and others (n=14, 26.9%) showed normal findings. Between the normal and abnormal NCS groups, there is no statistically significant difference on demographics or clinical features. CONCLUSIONS: We clarify the clinical features and sensory NCS findings of MP patients. Due to several limitations of sensory NCS, the diagnosis of MP could be accomplished both clinically and electrophysiologically.

Have You Ever Heard about Meralgia Paresthetica?

Meralgia paresthetica (MP), first described in 1878, is a sensory mononeuropathy of the lateral femoral cutaneous nerve (LFCN) characterized by pain, tingling, numbness, and paresthesias localized to the anterolateral thigh. There are many etiologies for MP, including those that are spontaneous (idiopathic, metabolic or mechanical) and iatrogenic (surgery, trauma). A 46-year-old female came to our emergency department (ED) with a right hip pain that developed after two days of an altered mental status from high amounts of multiple drugs (benzodiazepine, SSRI, and antipsychotics) to commit suicide. Her past medical and surgical histories were unremarkable. In addition, her vital signs were stable and her electrocardiography was unremarkable. On the other hand, laboratory tests showed an elevated creatinine kinase 14787 IU/L (normal range, 26~140 IU/L) and urine myoglobin >1000 ng/mL (normal range, 0~10 ng/mL). She was admitted to our ED for the management of rhabdomyolysis. The patient didn't slip down and slept on her right side for a long period. An initial pelvis and femur x-ray ruled out a fracture and a straight leg raise test was negative. We took a lumbar spine x-ray to rule out a herniated intervertebral disk because she complained of pain in the second and third lumbar distribution of her right thigh. These x-rays were unremarkable. We presumed she had a hip and thigh contusion and gave her painkillers, but her symptoms did not improved. After a day, the patient complained of numbness (5/10) rather than pain. We then suspected peripheral neuropathy. Her electromyography and nerve conduction velocity confirmed right LFCN neuropathy, MP. MP is often clinically diagnosed and treated conservatively. It is a neurologic disorder due to the entrapment of the LFCN. This case shows that a long period lacking in movement can cause MP. In future cases, the possibility of peripheral neuropathy should be considered, especially in mentally altered patients after drug intoxication.

Neurolysis for Megalgia Paresthetica

OBJECTIVE: Meralgia paresthetica (MP) is a syndrome of pain and/or dysesthesia in the anterolateral thigh that is caused by an entrapment of the lateral femoral cutaneous nerve (LFCN) at its pelvic exit. Despite early accounts of MP, there is still no consensus concerning the effectiveness of neurolysis or transaction treatments in the long-term relief for medically refractory patients with MP. We retrospectively analyzed available long-term results of LFCN neurolysis for medically refractory MP in an effort to clarify this issue. METHODS: During the last 7 years, 11 patients who had neurolysis for MP were enrolled in this study. Nerve entrapment was confirmed preoperatively by electrophysiological studies or a positive response to local anesthetic injection. Decompression of the LFCN was performed at the level of the iliac fascia, inguinal ligament, and fascia of the thigh distally. The outcome of surgery was assessed 8 weeks after the procedure followed at regular intervals if symptoms persisted. RESULTS: Twelve decompression procedures were performed in 11 patients over a 7-year period. The average duration of symptoms was 8.5 months (range, 4-15 months). The average follow-up period was 33 months (range, 12-60 months). Complete and partial symptom improvement were noted in nine (81.8%) and two (18.2%) cases, respectively. No recurrence was reported. CONCLUSION: Neurolysis of the LFCN can provide adequate pain relief with minimal complications for medically refractory MP. To achieve a good outcome in neurolysis for MP, an accurate diagnosis with careful examination and repeated blocks of the LFCN, along with electrodiagnosis seems to be essential. Possible variation in the course of the LFCN and thorough decompression along the course of the LFCN should be kept in mind in planning decompression surgery for MP.

Femoral Neuropathy and Meralgia Paresthetica Secondary to an Iliacus Hematoma

Compressive femoral and lateral femoral cutaneous neuropathies from an iliacus hematoma are unusual presentation. We report a case of a 16-year-old boy who developed right femoral and lateral femoral cutaneous neuropathies as a complication of traumatic ipsilateral iliacus hematoma formation. The patient complained of numbness in the right thigh and calf as well as right leg weakness, and pain in the right inguinal area. Nerve conduction study and needle electromyography identified the neuropathies. After the electrodiagnostic studies, the pelvic bone MRI revealed a large, 9x5x4.5 cm right iliacus hematoma. As a result, diagnosis of a right iliacus hematoma compressing the femoral and lateral femoral cutaneous nerves was made, and the patient underwent an operation to remove the hematoma. Symptoms and neurological signs showed notable improvement after surgical decompression. Subsequent follow-up electrodiagnostic studies after 11 weeks demonstrated regeneration evidence.

Ultrasound-guided Lateral Femoral Cutaneous Nerve Block in Meralgia Paresthetica

Meralgia paresthetica is a rarely encountered sensory mononeuropathy characterized by paresthesia, pain or sensory impairment along the distribution of the lateral femoral cutaneous nerve (LFCN) caused by entrapment or compression of the nerve as it crossed the anterior superior iliac spine and runs beneath the inguinal ligament. There is great variability regarding the area where the nerve pierces the inguinal ligament, which makes it difficult to perform blind anesthetic blocks. Ultrasound has developed into a powerful tool for the visualization of peripheral nerves including very small nerves such as accessory and sural nerves. The LFCN can be located successfully, and local anesthetic solution distribution around the nerve can be observed with ultrasound guidance. Our successfully performed ultrasound-guided blockade of the LFCN in meralgia paresthetica suggests that this technique is a safe way to increase the success rate.

Pulsed Radiofrequency Neuromodulation Treatment on the Lateral Femoral Cutaneous Nerve for the Treatment of Meralgia Paresthetica

We describe a rare case of pulsed radiofrequency treatment for pain relief associated with meralgia paresthetica. A 58-year-old female presented with pain in the left anterior lateral thigh. An imaging study revealed no acute lesions compared with a previous imaging study, and diagnosis of meralgia paresthetica was made. She received temporary pain relief with lateral femoral cutaneous nerve blocks twice. We performed pulsed radiofrequency treatment, and the pain declined to 25% of the maximal pain intensity. At 4 months after the procedure, the pain intensity did not aggravate without medication. Pulsed radiofrequency neuromodulation treatment on the lateral femoral cutaneous nerve may offer an effective, low risk treatment in patients with meralgia paresthetica who are refractory to conservative medical treatment.

Meralgia paresthetica affecting parturient women who underwent cesarean section: A case report / 대한마취과학회지

Meralgia paresthetica is commonly caused by a focal entrapment of lateral femoral cuteneous nerve while it passes the inguinal ligament. Common symptoms are paresthesias and numbness of the upper lateral thigh area. Pregnancy, tight cloths, obesity, position of surgery and the tumor in the retroperitoneal space could be causes of meralgia paresthetica. A 29-year-old female patient underwent an emergency cesarean section under spinal anesthesia without any problems. But two days after surgery, the patient complained numbness and paresthesia in anterolateral thigh area. Various neurological examinations and L-spine MRI images were all normal, but the symptoms persisted for a few days. Then, electromyogram and nerve conduction velocity test of the trunk and both legs were performed. Test results showed left lateral cutaneous nerve injury and meralgia paresthetica was diagnosed. Conservative treatment was implemented and the patient was free of symptoms after 1 month follow-up.

Prone Position-Related Meralgia Paresthetica after Lumbar Spinal Surgery : A Case Report and Review of the Literature

Lateral femoral cutaneous neuropathy occurring during spinal surgery is frequently related to iliac bone graft harvesting, but meralgia paresthetica (MP) can result from the patient being in the prone position. Prone position-related MP is not an uncommon complication after posterior spine surgery but there are only few reports in the literature on this subject. It is usually overlooked because of its mild symptoms and self-limiting course, or patients and physicians may misunderstand the persistence of lower extremity symptoms in the early postoperative period to be a reflection of poor surgical outcome. The authors report a case of prone position-related MP after posterior lumbar interbody fusion at the L3-4 and reviewed the literature with discussion on the incidence, pathogenesis, and possible risk factors related to this entity.

Anatomical Considerations of the Lateral Femoral Cutaneous Nerve Related to Nerve Conduction Study

OBJECTIVE: Lateral femoral cutaneous nerve (LFCN) conduction study is an objective measure for the diagnosis of meralgia paresthetica. Sensory nerve action potential of LFCN is not frequently evoked because of anatomical variations around inguinal area. The purpose of this study is to support the diagnosis of meralgia paresthetica by considering anatomical variations of LFCN in Korean adult cadavers. METHOD: Eighteen lower limbs of total nine adult cadavers were studied. Men were five and women were four. The points that LFCN or the main branch of LFCN met the imaginary line from anterior superior iliac spine (ASIS) to pubic tubercle and to lateral border of patella were recorded, respectively and distances from ASIS to those points were measured. RESULTS: The distance from ASIS to the point that LFCN or the main branch of LFCN met the imaginary line from ASIS to pubic tubercle and to lateral border of patella was respectivlely 1.36+/-0.68 cm (minimal 0.2, maximal 3.0) and 10.74+/-5.68 (minimal 3.3, maximal 20.1) cm. There was no significant distance difference between men and women. CONCLUSION: This study showed anatomic variations of LFCN around ASIS and femoral part. This knowledge may help LFCN conduction study for the diagnosis of meralgia paresthetica.

Surgical Results of Meralgia Paresthetica

OBJECTIVE: Meralgia Paresthetica is an entrapment neuropathy involving the lateral femoral cutaneous nerve. The aim of the present study is to evalute results of two surgical procedures(neurolysis and transection) for this disease. METHODS: The authors reviewed the 11 patients who underwent surgery in our hospital for meralgia paresthetica for last 15 years. Preoperatively all patients were treated by conservative management which was failed. Visual analogue scale(VAS) sore was used for pre-and post-operative assessments of the pain. Operation is performed by infrainguinal ligament approach. Nine patients underwent neurolysis, and two patients underwent transection of the lateral femoral cutaneous nerve. The average follow-up period was 14.3 months. RESULTS: In 10 cases good relief of symptom was obtained, but in one case relief of symptom was not. Superior result of transection as a treatment for meralgia paresthetica was obtained. But, there was no statistically significant difference between two procedures because of small group. CONCLUSION: When surgery is indicated for patients in whom pain is severe and persistent despite adequate conserative management, it appears to offer good results.