| Objective:1.To comprehensively compare the results of posterior correction and fusion with segmental pedicle screw instrumentation versus with hybrid (proximal hooks and distal pedicle screws) constructs in adult scoliosis.2.To compare the radiographic and clinical outcomes of two methods: anterior-posterior spinal fusion (APSF) versus posterior spinal fusion (PSF) alone in patients with severe (Cobb angle between 75°and 100°) Lenke type 1 adolescent idiopathic scoliosis (AIS) curves, and find out whether the posterior pedicle screw techniques could achieve the same satisfy results with the APSF.Methods:1. A total of 70 adult scoliosis patients that underwent posterior fusion with hybrid instrumentation (35, Group A) or pedicle screw (35,Group B) instrumentation at a single institution were sorted and matched according to four criteria: similar patient age, fusion levels, identical Lenke curve type, and identical operative methods. Patients were compared according to radiographic changes, operative time, intraoperative blood loss, pulmonary function tests, and SRS24 outcome scores.2. All patients (n 126) who underwent spinal fusion (APSF or PSF) at Changhai Hospital between Jun.1998 and Jun.2005 were included for analysis, with 99 females and 27 males, the minimum follow-up was1 year after surgery (mean, 3.5 years; range, 1.0–8.2 years), the mean age of patients was 12.6 years (range, 10–17.8 years). We divided the patient into several groups, group A (APSF group) had 32 patients, group B (PSF group) had 94 patients. Subanalysis of the PSF only group identified three distinct groups based on implants: hook-only constructs (n 18) group B1, hybrid constructs of proximal hooks and distal pedicle screws (n 22) group B2, and pedicle screw-only constructs (n 54) group B3. Multiple radiographic measures were assessed. The primary and secondary statistical analyses performed were nonparametric analyses, using the Wilcoxon-Mann- Whitney tests and the Kruskal-Wallis test.Results:1. The preoperative major Cobb angle averaged 61°in the A group and 60°in the B group. Average major curve correction was 55% in the hybrid group and 65% in the screw group (P= 0.001). At 2-year follow-up, major curve correction was 45% and 61%, respectively (P<0.0001). At 2-year follow-up, thoracic sagittal Cobb angle changes between T5 and T12 were 1.4°decrease in the hybrid group and 6.4°decrease in the screw group compared with preoperative (P=0.023). There were no differences in the lowest instrumented vertebra below the lower end vertebra, operative time, and average estimated blood loss. Two years following surgery, the screw group demonstrated improved percent predicted pulmonary function values compared with that of the hybrid group. Postoperative total SRS24 scores were similar in both groups (hybrid group: 98 vs. screw group: 96) (P=0.15). There were no neurologic complications related to hybrid or pedicle screw instrumentation.2. There were no statistically significant differences between the A and B groups for gender, age, number of levels fused, Cobb measurement of preoperative coronal or sagittal thoracic curve magnitude. The APSF group, when compared with the PSF group, had greater final overall correction of the coronal curve (49.8°vs 39.7°, P =0.0075). There were no significant differences seen in the sagittal alignment from T5–T12 (P 0.3750) or the SRS outcomes data between the A and B only groups. Pedicle screw-only constructs (group B3) corrected the coronal Cobb measurements more than the other two groups (48.1°vs. hooks 39.7°vs. hybrid 37.3°, P 0.0218), and to a similar extent as to the APSF group with no statistically significant difference in coronal correction (PSF, 48.1°; APSF 49.8°; P 0.9524). There were no reoperations for implant failure/pseudarthroses in any of the patients.Conclusion:1. Both instrumentation methods offer similar junctional change, lowest instrumented vertebra, operative time, and postoperative SRS24 outcome scores in the operative treatment of AIS. Pedicle screw instrumentation offers a significantly better major curve correction and postoperative pulmonary function values without neurologic problems compared with hybrid constructs.2. APSF of Lenke type 1 severe AIS allows greater coronal correction of thoracic curves between 75°and 100°, when compared with PSF alone using thoracic hook constructs or hybrid construct. However, the posterior approach of thoracic pedicle screw techniques could achieve the same effect and avoid the anterior release and ralated complications. |
