(Kiosk 4) Decoding an Electrodiagnostic Puzzle: A Case Report

Case Diagnosis: Severe left femoral neuropathy and possibly a superimposed left upper lumbosacral plexopathy or L2/L3 radiculopathy

Case Description or Program Description: 76 y.o. female that was referred for a NCS/EMG. She underwent a two part spinal fusion surgery from T4-L5 three months prior. The patient was unable to feel her left leg following the first part of the surgery. She reported weakness in left hip flexion and knee extension since the surgery. The patient also reported numbness throughout the proximal left lower extremity. She also had a "pins and needles" sensation in the right lower extremity. The patient was taking Gabapentin for her symptoms and was ambulating with a rolling walker. The patient had multiple falls due to left leg weakness.

Setting: Outpatient PM&R office

Assessment/Results: The electrodiagnostic findings were consistent with the following:
1. This is an abnormal electrodiagnostic study.
2. There is electrodiagnostic evidence of severe left femoral neuropathy.
3. Additionally, the above electrodiagnostic findings raise the concern for either a superimposed left upper lumbosacral plexopathy or L2/L3 radiculopathy given evidence of acute denervation seen in the adductor magnus muscle.
4. There is also electrodiagnostic evidence of axonal peripheral polyneuropathy in bilateral lower extremities based on sensory conduction testing.

Discussion (relevance): Femoral neuropathy is very rare, although most causes of femoral neuropathy are iatrogenic from surgery. Other causes of femoral neuropathy include hematoma formation, complication of femoral line placement, tumor or mass lesion, infection or abscess formation, diabetic amyotrophy, and bullet or stab wound. Following the electrodiagnostic study, we recommended a MRI to evaluate compression of the lumbar plexus nerves. We also recommended a left lower extremity orthotic (such as "Swedish knee cage") to prevent the left knee from buckling and to prevent falls.

Conclusions: This is a unique case that shows the importance an electrodiagnostic study can have on the diagnosis of a condition and predicting the prognosis. The patient in our case likely has severe femoral neuropathy due to excessive stretching of the nerve during the extensive spine surgery. This case also shows the effects femoral neuropathy can have on a patient and the recommendations we can make as physiatrists to improve the patient’s quality of life.