Lumbar Spine Alignment in Six Common Postures: An ROM Analysis With Implications for Deformity Correction.

STUDY DESIGN: A cross-sectional study of prospectively collected data. OBJECTIVE: To compare lumbar spine alignment in six common postures, and estimate loss in range of motion (ROM) relative to standing. SUMMARY OF BACKGROUND DATA: Ideal position for fusion of lumbar spine remains unknown. Although surgical fusion is necessary for deformity correction and symptom relief, the final position in which the vertebrae are immobilized should provide maximum residual function. METHODS: Data were collected prospectively from 70 patients with low back pain recruited over a year. All subjects had x-rays performed in slump sitting, forward bending, supine, half squatting, standing, and backward bending postures. ROM quantified in terms of sagittal global and segmental Cobb angles was measured from L1 to S1. Loss of ROM relative to standing was calculated for each posture. Analysis of variance and unpaired t tests were used to identify differences in alignment between postures. RESULTS: Slump sitting gives the greatest lumbar flexion followed by forward bending, and supine postures (P < 0.001). Backward bending produces greater lumbar extension than standing (P = 0.035). Half-squatting and standing postures were not significantly different (P = 0.938). For all postures, L4-5 and L5-S1 segments remained in lordosis, with L4-5 having greater ROM than L5-S1. L1-2 turns kyphotic in lying supine, L2-3 at forward bending, and L3-4 at slump sitting in the form of a "kyphosing cascade." Should the entire lumbar spine be fused in standing position from L1-S1, there would likely be a mean loss of 47.6° of lumbar flexion and 5.9° of lumbar extension. CONCLUSION: The present study demonstrates the extent of flexibility required of the lumbar spine in assuming various postures. It also enables comparison of the differences in degree of motion occurring in the lumbar spine, both across postures and across segments. Significant loss in ROM, particularly flexion, is anticipated with fusion modeled after the lordotic standing lumbar spine. LEVEL OF EVIDENCE: 2.

Evaluation of scoring systems and prognostic factors in patients with spinal metastases from nasopharyngeal carcinoma.

BACKGROUND CONTEXT: The decision for operative treatment of patients with spinal metastases is dependent on the patient's predicted survival. Tokuhashi, Tomita, Bauer, and Oswestry scores have been devised for survival prediction; however, none of these systems have been evaluated in nasopharyngeal carcinoma (NPC). PURPOSE: To investigate the accuracy of these scoring systems in predicting survival and to identify prognostic factors for survival of the patients with spinal metastases from NPC. STUDY DESIGN: Retrospective analysis of the patients with spinal metastases from NPC who were treated in our institution. PATIENT SAMPLE: The study included 87 patients with spinal metastases from NPC. OUTCOME MEASURES: The primary outcome measure was the survival time of these patients. The potential prognostic factors that are known to influence survival such as general condition, extraspinal bone metastases, vertebral bone metastases, visceral metastases, and neurologic assessment based on Frankel score were also studied. METHODS: The predicted survival according to the four scoring systems were calculated and labeled as "A" scores. These patients were then rescored by assigning NPC as a good prognostic tumor and labeled as "B" scores. The predicted survival of scores A and B were compared with actual survival. Potential prognostic factors of survival were investigated using univariate and multivariate Cox regression analyses. For all scoring systems, Kaplan-Meier survival estimates and log-rank tests were done; the predictive values were calculated using postestimation after Cox regression analyses. RESULTS: The median overall survival for the whole cohort was 13 (range 1-120) months. In multivariate analysis, general condition (p<.01), visceral metastases (p<.01), and vertebral metastases (p<.01) showed significant association with survival. The absolute score of all scoring systems was significantly associated with actual survival, which extended to the different prognostic subgroups of each scoring systems. Log-rank test revealed significant differences in survival between the different prognostic subgroups of all scoring systems (p<.01). Predictive value of survival by modified Tokuhashi score was the highest among all four scoring systems. CONCLUSIONS: Patients with spinal metastases from NPC have relatively good survival prognosis. All four scoring systems could be used to prognosticate these patients. The modified Tokuhashi score is the best in doing so.