Anesthesiology Expert Opines on Post-surgical Foot Drop

This case involves an elderly woman in Georgia who was referred to a neurosurgeon for removal of a herniated disk. After the procedure, which was completed without incident, the patient noted that her foot was numb. The patient continued to experience ongoing loss of sensation in the weeks following the procedure, and saw another doctor for diagnosis. After diagnostic testing, the cause of the woman’s injury was determined to be a severe peroneal nerve injury. Excluding direct damage to the nerve during the surgery, it was determined that the injury was most likely a result of a positioning error during the surgery. As a result of her injury, the woman suffers from debilitating foot drop.

Question(s) For Expert Witness

1. Do you routinely treat patients as described above?

2. Have you ever had a patient develop foot drop, subsequent to poor positioning?

Expert Witness Response E-001455

I frequently provide anesthesia for this procedure. I have never had a patient develop a foot drop from surgery in the prone position, although it is a common complication in procedures done in the lithotomy (legs in stirrups) position. The usual cause of a peroneal nerve injury is pressure against the lateral aspect of the lower leg (tibial tuberosity) as from an improperly padded stirrup. I have never heard of this happening in a prone case. Typically, positioning for surgery other than the standard supine position is done for the needs of the surgeon, and in many cases, the anesthesiologist has been spared from liability because of this. This is an uncommon injury, however nerve injuries to the lumbar nerve roots and lumbar plexus can surely result from the surgical manipulation required in a discectomy. There are only two things that I can postulate that could cause this injury that would be positioning related. One would be if the leg of the patient were hanging over the edge of the bed such that the metal frame of the bed were compressing the tibial tuberosity. This would be a rare event. In my institution, the patients are usually placed in a kneeling position, which requires a different extension on the table, and I think it would be impossible to compress the peroneal nerve in such a setup. The other would be improper flexion of the foot, but I would think if that happened, the injury would not be localizable to a discrete nerve, but would affect areas covered by multiple nerves.