More than what meets the eye in COVID-19 critical illness: A case report of bilateral femoral neuropathy due to psoas hematomas.

Bilateral femoral neuropathy is rare, especially that caused by bilateral compressive iliopsoas, psoas, or iliacus muscle hematomas. We present a case of bilateral femoral neuropathy due to spontaneous psoas hematomas developed during COVID-19 critical illness. A 41-year-old patient developed COVID-19 pneumonia, and his condition deteriorated rapidly. A decrease in the hemoglobin level prompted imaging studies during his intensive care unit (ICU) stay. Bilateral psoas hematomas were identified as the source of bleeding. Thereafter, the patient complained of weakness in both upper and lower limbs and numbness in the lower limb. He was considered to have critical illness neuropathy and was referred to rehabilitation. Electrodiagnostic testing suggested bilateral femoral neuropathy because of compression due to hematomas developed during the course of his ICU stay. The consequences of iliopsoas hematomas occurring in the critically ill can be catastrophic, ranging from hemorrhagic shock to severe weakness, highlighting the importance of recognizing this entity.

Magnetic resonance imaging of femoral nerve injury in the setting of anterior approach total hip arthroplasty.

PURPOSE: To illustrate MRI findings in patients with femoral neuropathy following anterior approach total hip arthroplasty (THA). METHODS: This was a retrospective review of patients who underwent MRI for femoral neuropathy following anterior approach THA between January 1, 2010, and July 1, 2022. Included patients had no preexisting neurologic condition. Clinical and diagnostic data were collected. MRIs were reviewed in consensus by 2 musculoskeletal radiologists. RESULTS: A total of 115 patient records were reviewed, 17 of which were included in the final analysis (mean age 64 years; 11 females). Study subjects presented with weakness with hip flexion and knee extension and pain and numbness in the femoral nerve distribution. In 7 subjects, the femoral nerve appeared normal. In 5 subjects, the femoral nerve was hyperintense on fluid-sensitive fat-suppressed imaging. In 4 patients, mass effect on the femoral nerve by either ill-defined soft tissue edema (n = 2), seroma (n = 1), or heterotopic ossification (n = 1) was detected. Only 1 patient had a nerve transection. Patients were imaged at a median time of 8 months (range: 1 day to 11 years) following arthroplasty placement. Clinical follow-up was available in 8 patients, of whom half had complete symptomatic resolution and half had partial improvement at a mean follow-up time of 39.3 months (SD 51.1). Of these 8, 1 underwent revision arthroplasty, 1 had removal of hardware, and another had excision of heterotopic ossification. CONCLUSION: MRI provides a means to directly evaluate the femoral nerve following anterior approach THA in both the immediate and chronic postoperative periods.

Meralgia Paresthetica as a Result of Surgery With an Emphasis on Harvesting Iliac Bone Grafts: A Review.

Meralgia paresthetica is a neurological disorder characterized by a symptom complex of numbness, burning, tingling, aching, or stabbing in the anterolateral portion of the upper thigh. Typically, this disorder is seen in patients with diabetes mellitus, obesity, and pregnancy. Also, it may result from a wide array of surgical interventions involving the region of the anterior superior iliac spine. Underlying pathophysiology concentrates on entrapment neuropathy of the lateral femoral cutaneous nerve (LFCN). Due to its location and wide anatomic variation, the LFCN is susceptible to compression, scarring, and injury during surgery. It is important to understand the regional anatomy. In addition, the plastic surgeon must have a working knowledge of the most common variations that can precipitate entrapment and increase susceptibility to injury during surgery. Surgeons lacking a substantial background on the numerous risk factors, origins, and anatomic variations of the LFCN may place patients at an even higher risk of damage to the nerve. An extensive knowledge of the anatomy and careful technique may be utilized by surgeons to prevent iatrogenic neuropathy of the LFCN.

Femoral neuropathy: A clinical and electrodiagnostic review.

INTRODUCTION/AIMS: Femoral neuropathies can cause severe, prolonged debility, yet there have been few clinical and electrodiagnostic (EDx) studies addressing this condition. The aim of this study was to better understand the etiologies, EDx features, and clinical course of femoral neuropathy. METHODS: We identified patients evaluated at Mayo Clinic Rochester between January 1, 1999 and July 31, 2019, with possible new femoral neuropathy ascertained via International Classification of Diseases-versions 9 and 10 diagnosis codes presenting within 6 months of symptom onset. RESULTS: A retrospective review of 1084 records was performed and we ultimately identified 159 patients with isolated femoral neuropathy for inclusion. The most common femoral neuropathy etiologies were compressive (40%), perioperative stretch (35%), and inflammatory (6%). Presenting symptoms included weakness (96%), sensory loss (73%), and pain (53%). Presenting motor physical exam findings demonstrated moderate weakness (34%) or no activation (25%) of knee extension and mild (32%) or moderate (35%) weakness of hip flexion. Seventy-two percent of patients underwent EDx testing, including 22 with femoral motor nerve conduction studies. Treatment often involved physical therapy (89%) and was otherwise etiology-specific. In patients with follow-up data available (n = 154), 83% had subjective clinical improvement at follow-up with a mean time to initial improvement of 3.3 months and mean time to recovery at final follow-up of 14.8 months. Only 48% of patients had nearly complete or complete recovery. DISCUSSION: In our cohort, the most common etiologies of femoral neuropathy were compression or perioperative stretch with high initial morbidity. Although motor recovery is common, improvement is often prolonged and incomplete.

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.

[Meralgia paraesthetica as complication of patient positioning : A not fully controllable risk]. / Meralgia paraesthetica als Lagerungsschaden : Kein voll beherrschbares Risiko.

Meralgia paraesthetica (MP) is the consequence of an entrapment or stretch injury of the lateral femoral cutaneous nerve at the crossing region with the inguinal ligament where the nerve exits the pelvis. It results in temporary or permanent sensory loss, paraesthesia and pain in the anterolateral region of the thigh. Idiopathic forms are known for example as seat belt syndrome or jeans syndrome. An MP can also occur as a complication of surgical or intensive care patient positioning. In focus are the lithotomy position, prone position and beach chair position.We analyzed 21 complaints about MP occurring for the first time postoperatively, which had been submitted to the expert committee for medical treatment errors at the North Rhine Medical Association over the past 10 years. Among these, six cases could be identified as positioning damage after a lithotomy position. In three cases MP occurred after supine positioning but the etiology could not be clarified with certainty. In 12 cases MP was recognized as a direct surgical complication.The pathophysiology, incidence and course as well as legal implications of position-related MP are discussed. Pressure damage to the nerve at its intersection with the inguinal ligament is assumed to be the main pathomechanism. Although all the cases presented here occurred after lithotomy positioning, the complication also appears to occur with other types of positioning according to the literature data, the most common being prone positioning. This also explains the increasingly published case reports of MP after prone positioning in COVID-19 patients for respiratory treatment. Safe avoidance of the positioning-related complication does not appear to be possible due to the anatomical variability of the course of the nerve and the unclear pathomechanisms.

Compressive femoral neuropathy caused by anticoagulant therapy induced retroperitoneal hematoma: A case report.

RATIONALE: Spontaneous retroperitoneal hematomas due to anticoagulant therapy rarely occur. Retroperitoneal hematomas can cause severe pain in the groin, quadriceps femoris muscle weakness, hemodynamic instability, and abdominal distension. They rarely cause compressive neuropathy of the femoral nerve transversing the iliacus muscle. Differential diagnosis is not easy because they have similar clinical features to retroperitoneal hematomas. PATIENT CONCERNS: A 72-year-old female patient whose right arm was stuck in a bookshelf for 5 days developed right cephalic vein thrombosis. After 5 days of intravenous heparin therapy for venous thrombosis, she presented with sudden right groin pain, right leg paresis, hemodynamic instability, and abdominal distension. DIAGNOSIS: Emergency abdominal and pelvic CT showed a large number of hematomas in the bilateral retroperitoneal space with active bleeding of the right lumbar artery. An electrodiagnostic study was performed 2 weeks later to check for neuromuscular damage in the right lower extremity, and right compressive femoral neuropathy was confirmed. INTERVENTIONS: Heparin therapy was discontinued; emergency embolization of the lumbar artery was performed. After 2 weeks, the patient started receiving physical, occupational, and transcutaneous electrical stimulation therapies. OUTCOMES: She became hemodynamically stable after arterial embolization; a significant decrease in hematoma and patency of the femoral nerve was confirmed on follow-up pelvic MRI. After 2 months of comprehensive rehabilitation, the muscle strength of the right leg significantly improved, and the pain disappeared. LESSONS: Although rare, spontaneous retroperitoneal hematomas may occur in patients receiving anticoagulant medications. They may even occur in patients receiving emergency anticoagulant therapy. Compressive femoral neuropathy due to retroperitoneal hematomas should be considered if muscle weakness and groin pain are observed. Early diagnosis and appropriate treatment plan of compressive femoral neuropathy due to retroperitoneal hematoma are helpful for a good prognosis.

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 Caused by Melorheostosis Affecting the Ipsilateral Ilium: A Case Report.

CASE: A 51-year-old woman presented with a 2-month history of pain in the right thigh. Radiography and computed tomography of the pelvis showed cortical hyperostosis of the right ilium. She was diagnosed with meralgia paresthetica (MP) caused by melorheostosis involving the right ilium. After 6 weeks of conservative management, an operation was performed for the persisting pain. At the 1-year follow-up, no findings of recurrence were observed clinically and radiographically. CONCLUSION: MP, caused by proximal irritation of the lateral femoral cutaneous nerve, can occur because of melorheostosis, which is a rare condition.

[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.

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.

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.

Severe Postpartum Femoral Neuropathy: A Case Series.

BACKGROUND: Femoral neuropathy is a rare complication of vaginal delivery that is often under-reported. It is marked by weakness and sensory loss in the lower limbs. This report presents 3 cases to outline possible prevention strategies, as well as to describe the process of diagnosis, management, and recovery for this injury. CASES: Diagnosis is made clinically, and prognosis is determined by clinical follow-up along with nerve conduction studies and electromyography. Management involves interdisciplinary efforts with physiotherapy. Prevention includes frequent repositioning and avoidance of hip hyperflexion during labour. The expected recovery period ranges from 2 to 24 months. CONCLUSION: Femoral neuropathy after vaginal delivery is under-reported. Though prognosis is often excellent, special attention to positioning during labour, prompt clinical diagnosis, and interdisciplinary management are essential for this rare injury.