The Influence of No Fault Compensation on Functional Outcomes After Lumbar Spine Fusion.

STUDY DESIGN: Prospective cohort study and systematic literature review. OBJECTIVE: To compare the functional outcomes for lumbar spinal fusion in both compensation and noncompensation patients in an environment of universal no fault compensation and then to compare these outcomes with those in worker's compensation and nonworkers compensation cohorts from other countries. SUMMARY OF BACKGROUND DATA: Compensation has an adverse effect on outcomes in spine fusion possibly based on adversarial environment, delayed resolution of claims and care, and increased compensation associated with prolonged disability. It is unclear whether a universal no fault compensation system would provide different outcomes for these patients. New Zealand's Accident Compensation Corporation (ACC) provides universal no fault compensation for personal injury secondary to accident and offers an opportunity to compare results with differing provision of compensation. METHODS: A total of 169 patients undergoing lumbar spinal fusion were assessed preoperatively, at 1 year, and at long-term follow-up out to 14 years, using functional outcome measures and health-related quality-of-life measures. Comparison was made between those covered and not covered by ACC for 3 distinct diagnostic categories. A systematic literature review comparing outcomes in Worker's Compensation and non-Compensation cohorts was also performed. RESULTS: The functional outcomes for both ACC and non-ACC cohorts were similar, with significant and comparable improvements over the first year that were then sustained out to long-term follow-up for both cohorts. At long-term follow-up, the health-related quality-of-life measures were the same between the 2 cohorts.The literature review revealed a marked difference in outcomes between worker's compensation and non-worker's compensation cohorts with a near universal inferior outcome for the compensation group. CONCLUSION: The similarities in outcomes of patients undergoing lumbar spine fusion under New Zealand's universal no fault compensation system, when compared with the dramatically inferior outcomes for these patients under other worker's compensation systems, suggest that the system of compensation has a major influence on patient outcomes, and that change of compensation to a universal no fault system is beneficial for patients undergoing lumbar fusion surgery. LEVEL OF EVIDENCE: 2.

What is the optimum fusion technique for adult isthmic spondylolisthesis--PLIF or PLF? A long-term prospective cohort comparison study.

STUDY DESIGN: Long-term prospective observational cohort study. OBJECTIVE: The objective of the study was to compare the long-term functional outcomes of posterolateral fusion (PLF) and posterior lumbar interbody fusion (PLIF) for the treatment of adult isthmic spondylolisthesis (IS). SUMMARY OF BACKGROUND DATA: PLIF has the theoretical advantage of improving sagittal alignment and providing a larger, more consistent fusion mass in patients with IS compared with PLF. Studies to date though have not shown a clinical difference, with follow-up of 2 years. METHODS: An prospective cohort study was performed of a single surgeon's patients with IS treated surgically over a 10-year period. Average follow-up was 7 years and 10 months. Preoperative patient characteristics between the 2 groups were not significantly different. The return rate of the long-term questionnaires was 83%. Outcome measures were the Roland Morris Disability Questionnaire (RMDQ), Low Back Outcome Score (LBOS), Short Form (SF)-12v2, and SF-6D R2. RESULTS: PLIF provided better short-term and long-term results than PLF. The PLIF group had significantly better LBOS scores in the long term, and nonsignificantly better RMDQ scores. As measured by the RMDQ Minimal Clinically Important Difference set at 4 and 8, the LBOS Minimal Clinically Important Difference set at 7.5 points and by SF-12v2 Physical Component Score, PLIF patients performed better than PLF patients. When analyzing single-level fusions alone, the difference is more pronounced, with Physical Component Score, Mental Component Scores, and SF-6D R2 all being significantly better in the PLIF group rather than the PLF group. CONCLUSIONS: This study strongly supports the use of PLIF to obtain equivalent or superior clinical outcomes compared with PLF for spinal fusion for lumbar IS. Although there are considerable issues when commenting on the results of observational studies, the results of this study are the first to report long-term follow-up beyond 2 years, and further larger long-term randomized studies are suggested.

Quasi-static and cyclic compressive loading studies of the intervertebral disc with combined flexion and torsion / Estudo da compressão monotônica e cíclica associada à flexão e torção do disco intervertebral

Bovine caudal motion segments were used to investigate the loss of load-bearing ability of the intervertebral disc (IVD) under both quasi-static and cyclic compressive loading combined with torsion and flexion. While the response of the disc to both compressive hyper-flexion and hyper-torsion has been previously investigated much less is known about their individual and combined influence on compressive failure. Eighty motion segments dissected from 41 bovine tails were subjected to quasi-static and cyclic compression with added components of flexion and torsion. The four different combinations of flexion and torsion were 0º torsion/0º flexion, 10º torsion/15º flexion, 10º torsion/0º flexion and 0º torsion/15º flexion. Quasi-static compression failed to show any significant difference among the different combinations of torsion and flexion for failure stress, failure strain and compressive tangent modulus. Cyclic compression indicated a significant influence of torsion in reducing the disc's load-bearing ability. Cyclic loading provides a more sensitive tool for the assessment of potentially damaging mechanical parameters for the IVD.

Segmentos de cauda bovina foram utilizados para investigar a perda de capacidade de suporte de carga do disco intervertebral (IVD) sob compressão monotônica e cíclica combinada com torção e flexão. Embora a resposta do disco a hiper-flexão e hiper-torção compressiva já fora previamente investigada, pouco se conhece sobre suas influências individuais e combinada para a falha compressiva. Oitenta segmentos dissecados a partir de 41 caudas bovina foram submetidos a compressão monotônica e cíclica com componentes adicionais de flexão e de torção. As quatro combinações diferentes de flexão e torção foram 0º torção/0º flexão, 10º torção/15º flexão, 10º torção/0º flexão e 0º torção/15º flexão. A compressão monotônica não evidenciou qualquer diferença significativa entre as diferentes combinações de torção e flexão para tensão de ruptura, deformação em ruptura e módulo tangente. A compressão cíclica indicou influência significativa da torção na redução da capacidade de carga do disco intervertebral. A carga cíclica proporciona uma ferramenta sensível para a avaliação de parâmetros mecânicos potencialmente deletérios ao IVD.

Spinous process morphology: the effect of ageing through adulthood on spinous process size and relationship to sagittal alignment.

STUDY DESIGN: Blinded radiographic analysis of CT scans reformatted for precise lumbar spinous process (LSP) measurement. OBJECTIVE: To investigate the effect of ageing on LSP morphology and influence of LSP morphology on lumbar spine sagittal alignment. SUMMARY OF BACKGROUND DATA: There is little data reporting the influence of ageing on spinous process size. There is data describing the increase in size of other body parts with age, such as the femur, ears, vertebral body, and nose. Several old cadaveric and radiographic studies have reported the formation of osseous spurs within the supraspinous and interspinous ligaments. METHOD: 200 abdominal CT scans taken for trauma and vascular investigation were reformatted to allow precise bony measurement of the lumbar spine. Two observers were blinded from the age and demographics of the patients. Sagittal and coronal plane projections were used to measure the height and width of the spinous processes (L1-L5), respectively. The relationship between spinous process size, age, and supine lordosis was investigated. RESULTS: LSP height increases by 0.03-0.07 mm/year (p < 10(-3) to 10(-8)) and width by 0.05-0.06 mm/year (p < 10(-11) to 10(-15)). Lumbar lordosis decreases with increasing LSP height (p < 0.0004) but is not related to increasing LSP width (p = 0.195). Supine lordosis increases by 0.1°/year (p = 0.004). CONCLUSIONS: This study demonstrates that the dimensions of the LSP change with age. Increases in LSP height and even more impressive increases in LSP width occur with advancing age. There is an inverse relationship between lumbar lordosis and LSP height.