ABSTRACT
STUDY DESIGN: A retrospective clinical and radiological analysis. OBJECTIVES: To evaluate the availability of anterior cervical plating in the treatment of distractive-flexion injuries of the lower cervical spine. SUMMARY OF LITERATURE REVIEW: Surgical approaches for distractive-flexion injuries of the lower cervical spine have included the anterior approach, the posterior approach, and the combined anterior and posterior approach. However, which approach is the most useful remains a controversial issue. MATERIALS AND METHODS: We reviewed the outcomes of 30 patients, who were followed-up for an average of 16 months (range, 12-43 months) after undergoing fusions with anterior cervical plating for distractive-flexion injuries of the lower cervical spine from July 1995 to July 2004. The average age of these patients was 52.9 years (range 24-77 years) and male-to-female ratio was 26:4. Group A consisted of 19 cases that were composed of unilateral dislocations and Group B consisted of 11 cases that were composed of bilateral dislocations based on Allen s classification. Group A1 (9 cases) and B1 (8 cases) were composed of cases that had fractures on the superior end plates or facet joints of the lower cervical spine in each group. Group A2 (10 cases) and B2 (3 cases) were composed of cases without fractures in each group. Neurologic symptoms were evaluated by the Frankel classification; and the angle of lordosis, disc height, and duration of bony union were analyzed postoperatively and with the last follow-up roentgenograms. RESULTS: Clinically, 22 (73%) patients had neurologic deficits, which were composed of 9 (41%) cases of complete injury, 7 (32%) cases of incomplete injury, and 6 (27%) cases of nerve root injury. The nerve root injuries recovered in all cases and the incomplete injuries had an average 1.7 grade recovery by the Frankel classification. Radiologically, the loss of lordosis was 2.2+/-1.7degrees in group A, 3.1+/-2.8degrees in group B (p=0.359), 3.0+/-1.6degrees in group A1, 1.5+/-1.5degrees in group A2 p=0.048), 3.5+/-3.1degrees in group B1, and 2.1+/-1.7degrees in group B2. Loss of disc height was 1.7+/-1.1 mm in group A, 2.2+/-0.9 mm in group B( p=0.201), 2.2+/-0.9 mm in group A1, 1.2+/-1.0 mm in group A2 (p=0.046), 2.5+/-0.6 mm in group B1, and 1.2+/-1.1 mm in group B2. The duration for bony union was 12.9+/-2.8 weeks in group A, 14.1+/-2.7 weeks in group B (p=0.044), 13.9+/-2.1 weeks in group A1, 11.9+/-3.0 weeks in group A2 (p=0.046), 14.4+/-2.9 weeks in group B1, and 13.3+/-2.3 weeks in group B2. There was no graft displacement, nonunion or metal failure. CONCLUSION: Anterior cervical plating was an effective treatment modality for distractive-flexion injuries of the lower cervical spine. and more firm method was necessary to surgical treatment in case of fractures on superior end plate or facet joint.
Subject(s)
Animals , Humans , Classification , Joint Dislocations , Follow-Up Studies , Lordosis , Neurologic Manifestations , Retrospective Studies , Spine , Transplants , Zygapophyseal JointABSTRACT
OBJECTIVE: The aim of this study is to biomechanically assess the pullout strength of the dynamic osteosynthesis construct(DOC) cervical plating system to consider the effects of screw triagulation in the cervical spine. METHODS: Twelve fresh cadaveric cervical spines(C4-C7) were randomly instumented with DOC cervical system with 20 degree(six specimens) or 30 degree platforms(six specimens). All specimens were tested on an MTS Alliance RT/10 testing machine. Load-displacement data was sampled at a rate of 50Hz. After the biomechanical testing, specimens were cut on sagittal plane and the penetrating depths of screw were measured. RESULTS: Mean insertion torque of 20 degree was 1.025 newton-meters and that of 30 degree was 1.031 newton-meters(p>0.05). Mean penetration depth of 20 degree was 11.82mm(C4), 12.20mm(C7) and that of 30 degree platforms were 12.22mm(C4), 13.04mm(C7). Mean pullout strength with 20 degree platforms was 642.2 N ; with 30 degree platforms was 537.7N(p>0.05). CONCLUSION: There is no statistical differences in pullout strength between 20 degree platform and 30 degree platform that were plated in cervical vertebral bodies, even though a literature shows that more increased screw angulation of 30 degree than that of 20 degree would decrease pullout resistance due to less amount of bone purchase against the pullout force in parallelogram shaped cervical vertebral body.
Subject(s)
Cadaver , Spine , TorqueABSTRACT
OBJECTIVES: We retrospectively studied the efficacy of anterior cervical discectomy and interbody fusion without plate fixation in degenerative cervical disease. METHODS: Thirty two consecutive patients with degenerative cervical disease treated by decompression and interbody fusion(Smith-Robinson technique) without anterior cervical plating were studied for postoperative complication rate as well as the clinical and radiologic outcomes and were compared the result of ours with other reported series where the anterior cervical plating was used. RESULTS: All cases were reviewed after average period of 13 months for the purpose of this study. There were 4 postoperative complications related to grafting. A solid fusion was obtained in all cases with single-level fusion(n=21) and 81.8 % of the cases with a two-level fusion(n=11). The overall fusion rate was 93.8 % and fusion rate per level fused was 95.3%. The clinical outcome of the patients was comparable with that in the literature, with one patient having a poor result. Comparing the result of this study with others of the anterior cervical plating, clinical outcome and fusion rate were not superior in plate fixation group in single-level fusion, but increased fusion rate and decreased graft-related complication rate were noted in multilevel fusion with plate fixation. However, the clinical outcome was not superior to noninstrumented fusion group of this study. CONCLUSION: These results demonstrate that anterior cervical discectomy and interbody fusion(Smith-Robinson technique) without instrumentation is safe and reliable method of single-level fusion in degenerative cervical disease. Plate fixation system doesn't seem necessary in single level fusion in degenerative cervical disease.