Surgical choices for cervical OPLL

ABSTRACT

Ossification of the posterior longitudinal ligament [OPLL] is a common cause of cervical myelopathy, especially in Japan, and is more common in males. OPLL is classified into four types segmental, continuous, mixed and focal. Different surgical approaches are being used to treat this disease, including laminectomy, laminoplasty and anterior, either resecting the ligament or decompressing the cord using the floating technique, leaving the ossified ligament in place. This study included sixteen patients with cervical OPLL treated at Alexandria main University Hospital during a period of two years [July 2001 to July 2003]. The age of the patients ranged from 45-67 years, with a mean age of 58.12 years. Fourteen patents were males and two were females. All patients excluding 2 presented with gradual progressive manifestations. The remaining 2 patients presented with acute onset quadriplegia after minor trauma. Upper extremity weakness and clumsiness, gait difficulty, sphincter dysfunction and neck pain were the most common complaints. Clinical evaluation and outcome of the patients was carried out using the Nurick scale. Fifteen of our patients suffered radiculomyelopathy. One patient with focal OPLL suffered radiculopathy in the distribution of right C6 root. Ten patients improved and six patients remained stationary during a follow-up period of six months. Plain x-rays, magnetic resonance imaging and computed tomography scan were done for all patients. Ossification posterior longitudinal ligament was found to be the continuous type in thirteen cases, mixed in two cases and focal in one. The maximal thickness of the OPLL was 7 mm with a range of 3-7 mm and a mean of 4.3 mm. The most commonly affected levels were C2-C4. The effective canal diameter ranged from 5-13 mm with a mean of 9.8 mm. In this study we used conventional laminectomy in eleven cases, open door laminoplasty in four cases and the anterior approach in only one patient with focal OPLL. We measured the improvement according to the Nurick scale. Ten patients improved and six patients remained stationary during a follow-up period of six months. We concluded from this study that OPLL should be kept in mind in the differential diagnosis in cases of cervical myelopathy. The effective canal diameter and the range of motion of the cervical spine are the most important factors affecting the clinical picture in cases of OPLL. Early surgery is recommended for cases of OPLL because better results are obtained in younger patients with short duration of symptoms. Laminectomy is a simple surgical option in cases of continuous type OPLL, with a stable spine as proved by dynamic study. Laminoplasty is better used in extensive involvement of the spine if the dynamic films show a high range of movement. Anterior approach has the risk of neural injury and is better avoided, especially if dural invasion could be identified in the preoperative imaging study. Anterior approach can be used in focal type OPLL and if used in extensive OPLL. The floating technique is safer than other methods to excise the OPLL