Foot drop caused by a lesion in the thoracolumbar spine.

STUDY

DESIGN

Fifteen patients with foot drop caused by a thoracolumbar spine lesion were retrospectively investigated.

OBJECTIVE

To clarify surgical outcomes and prognostic factors for foot drop owing to thoracolumbar disease.

SUMMARY OF BACKGROUND DATA: Although the literature contains some reports of the surgical outcome for foot drop because of lumbar degenerative disease, to the best of our knowledge, little is known about foot drop resulting from thoracolumbar lesions.

METHODS

Thoracolumbar lesions were classified into 2 groups (ossification of the ligamentum flavum; OLF, and osteoporotic vertebral collapse; OVC). Mean age at surgery was 73.7 years (range, 62 to 84 y) and the average follow-up period was 50 months (range, 19 to 85 mo). We measured the muscle strength of the tibialis anterior (TA) before operation and at the last follow-up. Diagnosis (OLF or OVC), age, sex, preoperative TA strength, and palsy duration were compared according to surgical outcome.

RESULTS

Excellent or good surgical outcomes were seen in 87% of patients with foot drop. Of the 8 patients who were chairbound or bedridden preoperatively, 5 (62.5%) were able to walk with the aid of a cane at the last follow-up. OVC patients, those with palsy duration shorter than 3 months, and those with good TA muscle contraction in response to peroneal nerve stimulation had a better surgical outcome.

CONCLUSIONS

Prognosis of foot drop was much better when the causative lesion was at the thoracolumbar spine than when it was at the lumbar spine. Severe paralysis was not a poor prognostic factor.