Chronic ischemic monomelic neuropathy from critical limb ischemia.

Neurology 2001 Sep 25;57(6):1008-12

Weinberg DH, Simovic D, Isner J, Ropper AH.

Department of Neurology, Tufts University School of Medicine, St. Elizabeth’s Medical Center, Boston, MA 02135, USA. [email protected]

OBJECTIVE: To describe the peripheral neuropathy resulting from chronic and critical arterial leg ischemia. METHODS: The authors evaluated 19 patients on entry to a gene therapy treatment trial for chronic and critical leg ischemia. Measurements included medical history, examination, neurologic symptom (NSS) and neurologic examination (NES) scores, motor and sensory nerve conduction studies, and quantitative sensory testing. The critically ischemic leg was compared with the less affected contralateral limb. RESULTS: All patients experienced pain from skin ulceration or vascular claudication, but many also had rest pain (58%), numbness (58%), burning (42%), and paresthesias (37%) in the ischemic foot that were consistent with peripheral nerve ischemia. Only three patients (16%) were free of neuropathic symptoms. The most common asymmetric neurologic signs included hypalgesia (74%), toe weakness (64%), hyperesthesia (63%), and pallanesthesia (53%) in the distal leg. NSS and NES were more abnormal in the critically ischemic leg, as were distal motor, total motor, and sensory examination subscores (p < 0.01 for each). Sural sensory potentials were reduced or absent, frequently on both sides. The symptomatic limb had reduced tibial motor amplitudes and increased thermal (cold) sensory thresholds (p < 0.01 for both) whereas the distal latencies, conduction velocities, and vibration thresholds were similar in the two legs. CONCLUSIONS: There is a predominantly sensory neuropathy associated with chronic and critical limb ischemia. Neuropathic symptoms are often obscured by the effects of ischemia on other tissues. The neurophysiologic changes suggest that the underlying pathophysiology is a distal axonopathy affecting nerve fibers of all sizes. Measures of blood flow in the leg correlate with neurologic symptom scores, examination scores, and electrophysiologic testing

PMID: 11571325 [PubMed – indexed for MEDLINE]

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Lateral Femoral Cutaneous Nerve

From: www.wheelessonline.com 

– Anatomy:    

– LFCN, as its name suggests, is purely sensory;    
– it arises from L2 and L3, travels downward lateral to the psoas muscle, crosses the iliacus muscle (deep to fascia), passes either thru or underneath the lateral aspect of the inguinal ligament, and finally travels onto innervate the lateral thigh;
– it divides into anterior and posterior branches and supplies skin on lateral aspect of thigh;
– in the study by Hospodar et al (JTO 1999), the course of the nerve was variable, but was most commonly found at 10-15 mm from the ASIS and as far medially as 46 mm from the ASIS;
– in no specimen did the nerve pass lateral to the ASIS (eventhough historically the nerve is thought to pass lateral to the ASIS in 10% of population);
– in all specimens the nerve passed underneath the ilioginal ligament and anterior to the iliacus muscle; 

– Meralgia Paresthetica: 

– entrapment syndrome of the lateral femoral cutaneous nerve causing burning, numbness, and paresthesias down the proximal-lateral aspect of the thigh;
– may be idiopathic, be a result of trauma, previous operations, and in some cases may arise from Perthes Disease abduction splints;
– in idiopathic cases, the nerve may be encased in bone by the growing apophysis of the anterior superior iliac spine, or may be entrapped in fascia either proximal or distal to the ASIS;    
– diagnosis is made by:           
– reproduction of the pain by deep palpation just below the anterior superior iliac spine and by hip extension;           
– relief of pain by localized injection of lidocaine;    
– treatment: when diagnosis is not in doubt and the symptoms are severe, consider operative decompression at the site of constriction;

EMG and NCS

Electromyography (EMG) and nerve conduction studies (NCS) are tests that measure the electrical activity of muscles and nerves. Nerves send out electrical signals to make your muscles react in certain ways. Nerves also send signals from your skin to your brain, which then processes the signals, so you can experience a variety of skin sensations.

  • An EMG Test looks at the electrical signals your muscles make when they are at rest and when they are being used.
  • A Nerve Conduction Study measures how fast and how well the body’s electrical signals travel along your nerves. EMG and nerve conduction studies are used to help diagnose a variety of muscle and nerve disorders and to quantify the severity of your condition.


An EMG test helps find out if muscles are responding the right way to nerve signals. Nerve conduction studies help diagnose nerve damage or disease. When EMG tests and nerve conduction studies are done together, they help doctors tell if your symptoms are caused by a muscle disorder or a nerve problem. With EMG and NCS studies, your doctor can next select the best therapeutic option to help you.