All types of cervical laminoplasties for cervical spondylotic myelopathy (CSM) gave the same degree of postoperative neurological recoveries. However, postoperative neck functions differed according to degrees of intervention with posterior supporting elements of the neck (spinoligamentous complex, SLC). To obtain optimal postoperative neck function, SLC should be preserved. Laminar enlargement destroying SLC resulted in anterior tilt of neck, loss of cervical lordosis and loss of cervical range of motion (ROM) by 40–60% of preoperative ROM, whereas, tension-band laminoplasty (N.Tsuzuki et al. Int Orthop1996;20:275–84), which preserved SLC, maintained cervical alignment with loss of ROM by 20–40% of preoperative ROM, showing a better postoperative neck-function than that of other laminoplasties. However, about 70% of patients complained of some discomforts of the posterior neck even with good neck movements.

To obtain optimal postoperative neurological recovery, the timing of decompression was a key issue. Japanese Orthopaedic Association (JOA) score for cervical myelopathy (normal = 17 points) was used for neurological evaluation. One hundred and nine patients who underwent tension-band laminoplasty, were grouped into 3 groups according to preoperative JOA scores: group A with JOA score above 14 (10 patients), group B with JOA score between 11 and 13 (48 patients), and group C with JOA score below 10 (51 patients). Mean pre-/post- JOA scores and ratios of patients with postoperative JOA score above 16 for each group were as follows: 1

0.4/14.1, 34% for total patients, 14.6/16.5, 80% for group A, 11.9/14.8, 40% for group B, and 8.2/12.9, 20% for group C. There was a statistical difference among three groups.

It was concluded that decompression at the early stage with JOA score above 14 using tension-band laminoplasty might provide the best outcome to CSM-patients regarding neurological improvement and postoperative neck function.