Biomechanical efficacy of calcium phosphate cement in augmentation and restoration of anterior cervical unicortical screw fixation / 中国矫形外科杂志

[Objective]To evaluate the biomechanical efficacy of calcium phosphate cement(CPC)in augmentation and restoration of anterior cervical unicortical screw fixation.[Method]Anterior cervical unicortical screw were fixed in the cervical vertebra(C_(3~6)),pull-out test and cyclic bending test was performed and anti-shear test after cyclic bending.[Result]The pull out strength(pos)of restoration group and augmentation group were significantly higher than that in the control group,the statistic difference was also significant(P

The Efficacy of the Unicortical Screw in the Anterior Cervical Fusion of the Degenerative Cervical Spine Disease

Anterior cervical fusion without internal fixation destabilizes an already unstable spine and can result in tenuous bone graft stability and potential for incorporation. Anterior fusion of cervical spine with screw-plates is gaining in popularity in the management of anterior cervical spine instability. Eighty six cases that underwent anterior fusion with or without internal fixation and autogenous iliac bone graft were compared and analyzed. The pathologies included 40 cases of cervical disc disease, 43 of cervical spondylosis and 3 of ossification of posterior longitudinal ligament. Changes in the alignment of the total cervical spine and of the fused segment were evaluated in both groups. Dislodgement of the grafted bone, which was observed in 2 of 11 cases in the nonplate group, was not seen in the plate group. Hardware failure was developed in 3 of 24 cases in the bicortical group, but not in 51 cases in the unicortical group. Alignment of the cervical spine was corrected and relatively well manintained in the plate group compared with the nonplate group. We concluded that a unicortical screw fixation was superior than a bicortical screw and a fusion without plating system could not keep a cervical lordotic curve in the treatment of the degenerative cervical disease.

Anterior Cervical Fusion: A Retrospective Analysis of 152 Cases

Anterior cervical fusion has enjoyed an increasing acceptance and frequency of utilization in the treatment of symptomatic degenerative, traumatic, and neoplastic disorders. Since the introduction of plate systems, cervical fusion with fixation has become popularized. We present our experiences of 152 cases of cervical fusion in degenerative and traumatic lesions, focusing on their surgical results and complications, along with our opinions about the various plate systems we used. Between March 1993 and May 1996, 152 patients with symptomatic degenerative and traumatic cervical lesions between C3-4 and C7-T1 levels were treated with anterior cervical fusions. These patients were retrospectively studied according to their medical records and radiological studies. A comparison between various plate systems were also done. There were 110 men and 42 women, aged from 21 to 77 years. Mean follow up period was 17 months. Mean fused segments were 1.4. Various plate systems were used: Caspar plate system in 14 patients; Top plate in 102; Orion plate in 21; and none in 15. Dislodgement of bone graft, screw loosening, and fusion failure that required reoperation were occurred in 8 cases. None of them were initially treated with unicortical type screws. Asymptomatic esophageal perforation was developed in one case among them. In conclusion, anterior cervical fusion with screw plate system can be carried out with acceptable complication rate. Although relative follow up period was short, we concluded that the locking type screw plate system was superior than the classic bicortical screw system in their procedural simplicity, unnecessary penetration of posterior cortex, and elimination of the fear for the neurological complication.