OBJECTIVETo observe and compare the medium-long-term efficacy of Kurokawa's and modified Kurokawa's double door laminoplasty for the treatment of cervical disorders.

METHODSA retrospective analysis was performed to compare the outcomes and complications between two kinds of operations on 172 cases from January 2002 to December 2010, including 106 cases of cervical spondylotic myelopathy, 52 cases of cervical stenosis, 21 cases of cervical ossification of the posterior longitudinal ligament. Patients were divided into two groups according to two surgical methods: traditional group, including 51 male and 18 female patients, with mean age of (56 ± 18) years (35-76 years); modified group, including 75 male and 28 female patients, with mean age of (58 ± 20)years (35-80 years). The two groups were comparable and compared according to different data using t test, χ(2) test and rank sum test.

RESULTSAll patients were followed up continuously for (52 ± 33)months, 123 patients were followed up ≥ 2 years, 71 patients ≥ 5 years. All patients' Japanese Orthopaedic Association (JOA) score improved significantly at the latest follow-up(t = 3.420, P < 0.01); no significant difference between the patients' JOA score improvement rate of two groups. The postoperative incidence rate of axial symptoms in patients of modified group (3.9%) was significantly lower than the traditional group (14.5%) (χ(2) = 7.548, P < 0.05), and cervical intervertebral activity decreased in the modified group was better than the traditional group in the first 3 months postoperatively (27% ± 6% vs. 19% ± 4%,Z = 6.34, P < 0.05), but during the medium-long-term follow-up, no significant difference in the cervical intervertebral activity decreased between two groups.

CONCLUSIONSMedium-long-term efficacy of Kurokawa's and modified Kurokawa's double door laminoplasty is satisfied and reliable. Avoiding damaging of semispinalis cervicis insertion in spinous process of C2, the modified operation method can protect the extensor group of the neck muscle and reduce the incidence of postoperative axial symptoms better.