Fifteen cases of foot drop associated with lumbar disorders were investigated to identify the factors influencing clinical results.
Fifteen surgically treated cases, (9 males and 6 females) were followed up for an average period of 2 years and 7 months. The mean age at the time of operation was 54.1 years. Patients consisted of 10 cases of herniation of the nucleus pulposus (HNP), 4 cases with a combination of degenerative lumbar canal stenosis and HNP (combined stenosis), and one case of postoperative extradural hematoma. The results were evaluated using six grades of the tibialis anterior muscle strength with manual muscle testing (MMT). We considered the patients who were grade 4 or 5 by MMT to be recovered, the other 8 patients were judged to be not recovered. Results were compared and analyzed with reference to age, type of onset of foot drop, weakness of tibialis anterior muscle before surgery, type of lumbar disorder and the interval between onset of foot drop and surgery.
In this series, older patients tended not to recover. Patients whose foot drop had appeared gradually and/or whose muscular contraction was weak did not recover. Foot drop did not improve in the cases of combined stenosis, and patients who had surgery 3 weeks or more after onset did not recover.
