Technical Modification and Comparison of Results with Hirabayashi's Open-door Laminoplasty.

Kim, Young Sung; Yoon, Seung Hwan; Park, Hyung Chun; Park, Chong Oon; Park, Hyeon Seon; Hyun, Dong Keun

Original Article

Journal of Korean Neurosurgical Society 2007;42(3): 168-172.

Young Sung Kim, Seung Hwan Yoon, Hyung Chun Park, Chong Oon Park, Hyeon Seon Park, Dong Keun Hyun

Department of Neurosurgery, Inha University College of Medicine, Incheon, Korea. nsysh@inha.ac.kr

ABSTRACT

OBJECTIVE
Hirabayashi's open-door laminoplasty is a good procedure to use to treat patients with myelopathy of the cervical spine; however, the authors have experienced problems in maintaining an open-window in cervical spines after the surgery. The authors developed a modified method of the expanded open-door laminoplasty and compared the radiological and clinical results with those of the classical method.
METHODS
In the modified method, wiring fixation with lateral mass screws on the contra lateral-side instead of fixing the paraspinal muscle or facet joint, as in the classical methods, was used in the open window of the cervical spine. Fifteen patients with cervical myelopathy were treated using the classical method and 12 patients were treated using the modified method. Preoperative and postoperative clinical conditions were assessed according to the Japanese Orthopedic Association (JOA) score. The radiological results were compared with the preoperative and postoperative computed tomography (CT) findings.
RESULTS
In both methods, the clinical results revealed a significant improvement in neurological function (p<0.001). Image analysis revealed that the cervical canals were continuously expanded in patients treated using the modified methods. However, authors have observed restenosis during the follow-up periods in 4 patients treated using the original method. Progression to deformity and spinal instability were not observed in any of the patients in the radiological results.
CONCLUSION
Although analysis with a larger population and a longer follow-up period needs to be undertaken, our modified open-door laminoplasty has shown an advantage in better maintaining an open window in comparison with the Hirabayashi's open-door laminoplasty.

Key Words: Laminoplasty; Myelopathy; Ossification of the posterior longitudinal ligament; spondylosis