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.

[Two Cases of Femoral Nerve Palsy after Pelvic Surgery].

Postoperative femoral nerve palsy (FNP) is a rare complication associated with urologic surgery. Inappropriate use of retractors, use of lithotomy position, and prolonged surgery that lead to the femoral nerve compression have been reported as risk factors for FNP. Here, we report two cases of FNP after pelvic surgery. Case 1: A 47-year-old woman underwent ureterocystoneostomy for a giant ureterocele. On the first postoperative day, she developed muscle weakness and paresthesia in the left lower leg. An orthopedic surgeon diagnosed her with FNP associated with the surgery. Case 2: An 82-year-old woman underwent radical cystectomy for invasive bladder cancer. On the second postoperative day, she developed extension deficit in the left lower leg and was diagnosed with an iatrogenic FNP. Although this complication is infrequent, at onset, it leads to difficulty in walking and gait disturbance in the patient. As a result, it greatly reduces the patient's postoperative quality of life. Therefore, preventive measures should be taken to reduce the risk of this postsurgical nerve injury, such as appropriate placement of retractors and proper patient positioning during the operation.

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.

Risk factors of meralgia paresthetica after prone position surgery: Possible influence of operating position, laminectomy level, and preoperative thoracic kyphosis.

Obesity and a prolonged surgical duration are reported risk factors for meralgia paresthetica (MP) after prone position surgery; however, this fails to explain why MP seldom occurs after prone position craniotomy. We reviewed the incidence of MP after spinal surgery and craniotomy in the prone position and investigated whether unidentified factors are involved in the mechanism of postoperative MP. Between January 2014 and March 2020, we performed 556 prone position surgeries. We excluded patients aged ≤16 years and those who were comatose or who required redo-surgery, and reviewed 446 eligible patients (124 who underwent craniotomies and 322 who underwent posterior spinal surgeries). Postoperative MP occurred in 46 (10.3%) patients with a higher incidence after spinal surgery than after craniotomy (13.7% vs. 1.6%, p < 0.001). Among the 322 patients who received posterior spinal surgery, thoracic and lumbar laminectomies were associated with a higher incidence of MP than cervical laminectomy. Analyses limited to those patients who received thoracic and lumbar laminectomies revealed that the preoperative thoracic kyphosis (TK) angle was significantly greater in patients with MP than in those without MP (average TK angle, 38.9° vs. 23.1°; p < 0.001), and that the preoperative lumbar lordosis angle did not significantly differ between the two groups. Apart from the known predisposing factors, we found that thoracolumbar-sacral laminectomy in patients with a greater TK angle is also a risk factor for MP after prone position surgery.

[Meralgia paresthetica after prolonged prone position at the intensive care unit among COVID-19 patients. A case report]. / Långvarigt bukläge på IVA kan öka risken för meralgia paresthetica.

Meralgia paresthetica (MP) is an entrapment syndrome that may cause loss of sensation, numbness, paresthesia and pain within the distribution of the lateral femoral cutaneous nerve. This condition is more common in persons with diabetes mellitus, obesity and in old age. MP has previously been described in patients that have undergone surgery in the prone position (PP) and in a case report of a patient with ARDS (Acute Respiratory Distress Syndrome) who was cared for in the intensive care unit (ICU). Due to the COVID-19 pandemic PP has been widely used for periods of 12-16 hours to improve oxygenation. At the rehabilitation unit at our hospital, we have identified cases of MP in patients with COVID-19 that have required this type of positioning for long periods in the ICU. We would like to draw attention to the fact that there is a risk of peripheral nerve injury in the event of prolonged PP and recommend extra controls, careful positioning and extra padding at the areas where peripheral nerves may be exposed to pressure.

Femoral nerve compression caused by a hibernoma in the right thigh: a case report and literature review.

BACKGROUND: A hibernoma, also known as a brown fat tumor, is a rare benign soft tissue tumor, which originates from brown adipose tissue remaining in the fetus after the gestational period. It is often detected in adult men, presenting as a painless slow-growing mass. Hibernomas of the thigh have been reported; however, motor and sensory disorders caused by the tumors compressing the femoral nerve have not been reported. We report a case of a histopathologically proven hibernoma that induced femoral mononeuropathy. CASE PRESENTATION: A 26-year-old man was admitted to the hospital due to a mass, approximately 11.0 × 9.0 × 4.0 cm in size, that had developed 5 years ago in the anterolateral aspect of the proximal thigh. Furthermore, he had a history of hypoesthesia 1 month prior to his admission. He had signs and symptoms of both a motor and sensory disorder, involving the anterior aspect of the right thigh and the medial aspect of the calf, along the distribution of the femoral nerve. During surgery, the femoral nerve was found to be compressed by the giant tumor. The resultant symptoms probably caused the patient to seek medical care. Marginal resection of the mass was performed by careful dissection, and the branches of the femoral nerve were spared. Histopathology examination showed findings suggestive of a hibernoma. At the 4-month follow-up, no femoral nerve compression was evident, and local tumor recurrence or metastasis was not found. CONCLUSIONS: Asymptomatic hibernomas do not require treatment; however, in cases of hibernomas with apparent symptoms, complete marginal surgical excision at an early stage is a treatment option because it is associated with a low risk of postoperative tumor recurrence.

Spontaneous iliacus haematoma with femoral nerve palsy: an appeal to involve surgical teams early.

We report the case of a 68-year-old man who was placed on heparin as bridge therapy and subsequently developed an iliacus haematoma with associated femoral nerve palsy. His team involved the orthopaedic surgery team in delayed fashion after his symptom onset. Due to his active medical conditions, he did not undergo surgical decompression of his haematoma until late into his hospital course. Unfortunately, this patient did not regain meaningful function from his femoral nerve deficit. We believe this case highlights the high index of suspicion necessary for making this diagnosis as well as the repercussions of an untimely decompression for this acute, compressive neuropathy. Although we are surgeons and this is a surgical case, we hope to publish this case in a medical journal to raise awareness that surgical decompression does have a role in this diagnosis and should ultimately be pursued early in its course for optimal patient benefit.

Iliopsoas hematoma presenting with sudden knee extensor weakness: A case report.

RATIONALE: Hematoma of the iliopsoas muscle is a rare condition. Prolonged pressure conditions due to hematoma of the femoral nerve can cause severe pain in the affected groin, hip, and thigh, and quadriceps weakness. We report a rare case of a spontaneous iliopsoas muscle hematoma that caused sudden femoral neuropathy. PATIENT CONCERNS: A 71-year-old woman presented sudden left hip pain and knee extensor weakness. The pain was aggravated with left hip extension. She had a bilateral total hip replacement surgery due to avascular necrosis. She was diagnosed as mild stenosis of the cerebral artery and took aspirin to prevent cerebral artery atherosclerosis. DIAGNOSIS: A hip computed tomography scan demonstrated a suspicious fluid collection at the left iliopsoas bursa. We considered the possibility of lower limb weakness due to neuralgic amyotrophy and performed electromyography and enhanced lumbosacral magnetic resonance imaging (MRI). Electromyography finding showed left femoral neuropathy of moderate severity around the inguinal area was diagnosed. On MRI, left iliopsoas bursitis or hematoma, and displacement of the left femoral nerve due to the iliopsoas bursitis/hematoma were observed. INTERVENTION: Ultrasonography (US)-guided aspiration of the left iliopsoas hematoma was performed. We started steroid pulse therapy for 8 days. OUTCOMES: After US-guided aspiration and steroid pulse therapy, the patient's knee extension motor grade improved from grade 1 to 2, and the pain was slightly reduced. At 3 weeks after the aspiration procedure, her hip flexion motor grade had improved from grade 3+ to 4 at follow-up. LESSONS: Imaging studies are fundamental to diagnose of iliopsoas hematoma. Electromyography examination plays an important role in determining the prognosis of patients and lesion site. Despite the negligible change in sitting position, hematoma can develop. Physicians should consider hematoma that cause femoral neuropathy.

Carpal Tunnel Syndrome and Meralgia Paresthetica in Pregnancy.

IMPORTANCE: Carpal tunnel syndrome and meralgia paresthetica are 2 common neuropathies complicating pregnancy. Each of these causes significant discomfort but can be diagnosed and treated safely during pregnancy. OBJECTIVE: This article outlines the existing literature diagnosis, treatment, and prognosis of carpal tunnel syndrome and meralgia paresthetica, specifically looking at the implications during pregnancy. The aim is to provide a reference for physicians diagnosing and treating neuropathies in pregnant patients. EVIDENCE ACQUISITION: Existing literature on neuropathies during pregnancy, clinical presentation, and treatment options for both carpal tunnel syndrome and meralgia paresthetica was reviewed through a MEDLINE and PubMed search. Referenced articles were reviewed and used as primary source materials as appropriate. RESULTS: Carpal tunnel syndrome affects individuals of all ages and sexes but is more prevalent in women, particularly during pregnancy. Meralgia paresthetica can occur in various circumstances but is most commonly associated with prolonged second stage in lithotomy position. Multiple clinical signs and neurologic tests are useful to establish the diagnosis of either neuropathy. Effective treatment for carpal tunnel syndrome includes wrist splints, steroid and lidocaine injections, and release surgery. Optimal treatment of meralgia paresthetica remains controversial but includes nerve block injections and active release techniques. CONCLUSIONS AND RELEVANCE: Neuropathies are common in pregnancy and can result in significant impairment. Accurate diagnosis is possible during pregnancy and can usually be accomplished with bedside neurologic tests. Treatment options can be safely considered during pregnancy and can result in symptomatic improvement and reduction in chronic symptoms.

Meralgia paresthetica: finding an effective cure.

Meralgia Paresthetica (MP) is one of the most common mononeuropathies of the lower limb. MP usually resolves on its own, even without treatment. However, many physicians are not aware of this diagnosis and may confuse patients with another nerve disease such as radiculopathies. Although no motor symptoms are associated with this condition, the sensory dysfunctions are potentially debilitating to patients. The variable course of the lateral femoral cutaneous nerve also complicates treatments. Thus, the author recommends the use of ultrasonography to help locate the nerve. Many treatments for MP are available, but they are supported only by moderate to low-quality evidence. Treatments range from conservative to interventions using nerve blocks and surgery. Without a clear superiority of any treatment, the author concludes that treatment should be done in a stepwise fashion, from the noninvasive to the more invasive treatment if symptoms persist.

The Correlation of Meralgia Paresthetica and Spinal Surgery in Prone Position.

AIM: To investigate the incidence, risk factors, and recovery of patients with meralgia paresthetica (MP) following posterior spine surgery. MATERIAL AND METHODS: Patients who underwent posterior spine surgeries in prone position at the authors’ clinics were included in this study. Patients with preoperative MP were excluded. RESULTS: Among the 560 patients who underwent spine surgery in prone position, 117 (21%) had impaired sensation along the anterolateral aspect of the thigh. One hundred three of them were treated with conservative treatment, whereas 14 underwent surgery for MP. CONCLUSION: Conservative treatment is the first option for MP. Patients who do not recover with conservative treatment may undergo surgical treatment.

Anatomical Implications Regarding Femoral Nerve Palsy During a Direct Anterior Approach to Total Hip Arthroplasty: A Cadaveric Study.

BACKGROUND: Femoral nerve palsy is a serious neurological complication following total hip arthroplasty (THA) via a direct anterior approach. One hypothesis is that the nerve injury is caused by malpositioning of retractors over the anterior wall of the acetabulum. The purpose of this cadaveric study was to clarify the anatomical features of the femoral nerve around the anterior acetabular rim and the potential risk of nerve injury during a direct anterior approach to THA. METHODS: We dissected 84 cadaveric hips from 44 formalin-embalmed cadavers. When the cadavers were supine, the iliopsoas muscle and the femoral nerve were exposed and the anterior joint capsule and labrum were resected. The measurement points were determined along the acetabular rim every 30°, and a reference line was drawn from the anterior superior iliac spine to the center of the acetabulum, with the intersection of the rim at 0°. The minimum distance to the femoral nerve margin was measured from 0° to 150° (6 points). Other anatomical structures were measured to determine their association with the distance of the shortest measurement points. RESULTS: The mean minimum distances to the femoral nerve were 33.2 mm at 0°, 24.4 mm at 30°, 18.4 mm at 60°, 16.6 mm at 90°, 17.9 mm at 120°, and 23.2 mm at 150°, showing that the distance at 90° was the shortest (p < 0.001). The thickness of the iliopsoas muscle and the femoral length were positively associated with the distance to the femoral nerve at 90°. CONCLUSIONS: In this cadaveric study, the femoral nerve was within 16.6 to 33.2 mm of the acetabular rim at points from 0° to 150° of a line drawn from the anterior superior iliac spine. The nerve was closest to the rim at 90°, indicating that this is an area of high risk during retractor placement. CLINICAL RELEVANCE: Retractor placement at 90° to the anterior acetabular rim should be avoided to reduce the risk of femoral nerve injury.

[Research progress on meralgia paresthetica after posterior spine surgery].

Meralgia paresthetica (MP) after posterior spine surgery is caused by mechanical compression injury of lateral femoral cutaneous nerve, which presents as numbness or paresthesia in the confined area of the anterolateral thigh. MP after posterior spine surgery is a common postoperative complication, and the incidence is 12.7%-25.5%. Because its clinical manifestations are mild and easy to be ignored, often leading to treatment delays. This article mainly reviews the incidence, risk factors, prevention and treatment of MP after posterior spine surgery.

Compressive Femoral Mononeuropathy Secondary to Acetabular Labral Tear Associated With Paralabral Ganglion Cyst of an Osteoarthritic Hip: A Case Report.

CASE: A 61-year-old man presented with a 5-year history of left hip pain and a 6-month history of left groin swelling associated with hypoesthesia and proximal muscle weakness. Radiograph of the left hip showed degenerative joint disease. Magnetic resonance imaging revealed a large, anteriorly displaced paralabral cyst of the left hip joint. Neurophysiologic studies were corroborative of left femoral mononeuropathy. Complete excision of the cyst along with total hip replacement were performed. At 4-year follow-up, there was complete remission with resolution of symptoms. CONCLUSIONS: Our experience emphasizes the importance of identifying and addressing the underlying primary pathologic disease for a satisfactory functional outcome.

Laparoscopic-Assisted Intra-Abdominal Section of the Lateral Femoral Cutaneous Nerve for Meralgia Paresthetica Following Anterior Hip Arthroplasty.

BACKGROUND: Meralgia paresthetica, a pain syndrome that is caused by injury to the lateral femoral cutaneous nerve, is a well-documented complication after anterior hip arthroplasty (THA). Traditional treatment of this peripheral nerve entrapment syndrome can be complicated in patients who have had THA via an anterior approach owing to the presence of scar in the postoperative bed. CASE DESCRIPTION: In a 70-year-old man, we performed a novel laparoscopic-assisted intra-abdominal approach to treat meralgia paresthetica in the setting of previous anterior THA. CONCLUSIONS: Minimally invasive intra-abdominal treatment of meralgia paresthetica following anterior THA results in durable pain relief. This approach is a helpful alternative to traditional techniques of decompression or section of the lateral femoral cutaneous nerve below the inguinal ligament.

Management of Irreducible Hip Dislocations in Infants With Developmental Dysplasia of the Hip Diagnosed Below 6 Months of Age.

BACKGROUND: Infants with dislocated irreducible (D/I) hips can be substantially harder to treat than infants with dislocated but reducible hips. The purpose of this study was to compare treatment methods and outcomes for infants with D/I hips in order to optimize management of this difficult patient cohort. METHODS: A multicenter prospective hip dysplasia study database was analyzed from 2010 to 2016. Infants aged below 6 months with clinically and radiologically confirmed D/I hips were included in the study. Teratological hips (syndromic/neuromuscular) were excluded. RESULTS: In total, 59 hips in 52 patients were included. All hips were clinically Ortolani negative and radiologically dislocated but irreducible on presentation and had at least 20 months of follow-up. Mean age at diagnosis was 1.9 months (range, 0.1 to 5.9 mo). There were 33 left hips, 12 right hips, and 14 bilateral hips (7 patients). In total, 48 of 59 hips were treated in Pavlik harness. The remainder were treated by alternative braces or primary closed or open reductions. Pavlik treatment was successful in 27 of 48 hips. Pavlik treatment was abandoned in 21 D/I hips, 3 due to femoral nerve palsy and the remainder due to failure to achieve reduction. There was no statistical correlation between Pavlik success and age at diagnosis (P=0.22), patient sex (P=0.61), or bilateral compared with unilateral D/I hips (P=0.07). Left hips were more likely to be successfully reduced in Pavlik harness than right hips (P=0.01). Five complications occurred: 3 patients developed femoral nerve palsy in Pavlik harness, while 2 patients developed avascular necrosis, both after failed Pavlik treatment and subsequent surgery. CONCLUSIONS: Pavlik harness treatment has been demonstrated to be a safe and sensible first-line treatment for infants with D/I hips. Left hips were more likely to be successfully reduced in Pavlik harness than right hips, but age, sex, and bilaterality were not correlated. The outcomes demonstrated from this multicentre prospective database inform management of this complex patient cohort. LEVEL OF EVIDENCE: Level II-prognostic study: less-quality prospective study.

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.