Cervical spondylotic myelopathy: Patterns of neurological deficit and recovery after anterior cervical decompression

OBJECTIVES: We evaluated the specific pattern of pre- and postoperative neu rological signs and symptoms and functional results in patients with cervic al spondylotic myelopathy who underwent anterior decompressive operations. Additionally, we sought to determine which findings had predictive value fo r surgical outcome. METHODS: We retrospectively reviewed the records of 76 patients with cervic al spondylotic myelopathy caused by osteophytic ridge or intervertebral dis c herniation who underwent anterior cervical decompression and fusion perfo rmed by one surgeon. The patients were evaluated postoperatively by office visits and/or telephone interviews. Outcome was assessed by objective neuro logical examination and scoring with multiple functional rating scales. RESULTS: The most common preoperative symptoms were deterioration of hand u se (75 %), upper extremity sensory complaints (82.9%), and gait difficultie s (80.3%). In the upper extremities, preoperative weakness was most common in the hand intrinsic muscles (56.6%) and triceps (28.9%), and in the lower extremities, preoperative weakness was most common in the iliopsoas (38.8% ) and quadriceps (26.3%). In the lower extremities, individual muscle group s had strength improvement rates from 79.1 to 88.1 %; somewhat higher rates , from 81.3 to 90.9%, were observed in the upper extremities. When evaluate d by using the Cooper myelopathy scale, lower extremity functional improvem ent occurred in 46.7% of the patients and upper extremity functional improv ement in 75.4%. Overall functional improvement, evaluated by using a modifi cation of the Japanese Orthopedic Association Scale, was noted in 79.7% of the patients who had abnormal scores preoperatively. CONCLUSION: Strength improved at rates of approximately 80 to 90% in indivi dual muscle groups after anterior cervical decompression. However, fewer th an half of all patients experienced functional improvement in the lower ext remities, a discrepancy that was probably caused by persistent spasticity r ather than muscle weakness. Postoperative dysfunction in the upper extremit ies was caused by residual weakness as well as sensory loss. Recurrent symp tomatic spondylosis at unoperated levels was calculated to occur at an inci dence of 2% per year.