Elizabeth Raoof, MD
Resident Physician
MedStar National Rehabilitation Hospital/Georgetown University
North Potomac, Maryland, United States
Caroline McKenna, BS
Medical Student
Idaho College of Osteopathic Medicine
MD, Maryland, United States
Ross Puffer, MD
Neurosurgeon
WRNMMC
Bethesda, Maryland, United States
Ean Saberski, MD
Plastic Surgeon
WRNMMC
Bethesda, Maryland, United States
Aeneas Janze, N/A, MD
Staff Physician
Walter Reed National Military Medical Center
Silver Spring, Maryland, United States
Xiaoning Yuan, MD, PhD
Assistant Professor
Uniformed Services University of the Health Sciences
Bethesda, Maryland, United States
Lateral femoral cutaneous nerve (LFCN) impingement by sartorius enthesophyte
Case Description:
51-year-old active-duty female with recurrent right meralgia paresthetica, refractory to lifestyle modifications, weight loss, and injections. Symptoms worsened when supine and improved in upright positions. Physical exam revealed decreased sensation along the lateral thigh and absent Tinel’s sign at the inguinal ligament lateral to the anterior inferior iliac spine (ASIS).
She was treated in a Physical Medicine and Rehabilitation (PM&R) outpatient clinic at a military treatment facility, and received temporary resolution of symptoms from a perineural injection series with 5% dextrose. Magnetic resonance imaging of the right hip did not demonstrate evidence of nerve abnormality.
Given symptom recurrence, high-frequency ultrasound (HFUS) performed in PM&R clinic demonstrated LFCN impingement due to a sartorius enthesophyte at the level of the ASIS. She was referred to and evaluated in a multidisciplinary peripheral nerve clinic with PM&R, Neurology, Neurosurgery, and Plastic Surgery, and elected for surgical decompression with debridement to address her recurrent symptoms.
Discussions:
Meralgia paresthetica, or LFCN entrapment, is a common cause of lateral thigh paresthesia. The LFCN is a sensory peripheral nerve susceptible to entrapment under or through the inguinal ligament. The most common causes include obesity and external compression from tight clothing or belts. Diagnosis is typically clinical, based on the distribution of sensory abnormalities without weakness or abnormal reflexes. Patients are often counseled to lose weight or wear looser clothing. Although the LFCN is infrequently imaged, in this case, HFUS permitted the identification of LFCN impingement by a sartorius enthesophyte.
Conclusions:
HFUS can be performed point-of-care to assess nerve pathology in patients with symptoms concerning for meralgia paresthetica, particularly those with recurrence. By visualizing LFCN impingement by a sartorius enthesophyte, our multidisciplinary team could offer a more definitive treatment plan to address the patient’s symptoms.
