Development of a model for assessment and predicting outcome in surgery for degenerative disorder of the lumbosacral spine

Degenerative lumbosacral disorders involve the gradual loss of normal structure and function of the spine over time. The growth of the ageing population has led to an increase in the number of spinal surgery for degenerative lumbosacral disorder recommended when conservative treatment fails. Yet the clinical benefit of this surgery remains controversial when a significant number of patients fail to achieve the expected beneficial outcome. The overall aim of any surgical intervention in degenerative lumbosacral disorders should be to eliminate the primary pathology of the disease (e.g. loss of sagittal balance) to achieve an outcome that restores or improves patients' health-related quality of life (HRQL). In order to assess health-related quality of life, a plethora of outcome measures are employed in the speciality of spinal surgery. The ability to measure outcome of surgery and to predict which patients will have a good outcome from surgery is important for patients and the healthcare systems as a whole. The concept of maintaining or restoring spinal sagittal balance is essential in managing degenerative lumbosacral spine disorders. The focus of spinal fusion and deformity correction techniques are obtaining fusion of the diseased spinal column in the optimal balanced alignment in order to improve the long-term outcome of surgery. The spinal sagittal balance is characterized by both pelvic and spinal parameters. No single measurement can accommodate the entire spectrum of spinal curvatures. All methods available for assessing the spine in the sagittal plane have their strengths and caveats. The purpose of my PhD research is to establish that spinal surgery is a worthwhile surgical procedure in improving the health-related quality of life outcome for degenerative lumbosacral disorders by using the comparison model utilizing the generic HRQL outcome measure instrument (i.e. SF-12) to benchmark with established surgical procedures (i.e. total joint replacement surgery for osteoarthritis of the knees and hips). I also intend to develop a model for a simple and practical pre-operative assessment method utilizing the SF-12 scores as predictors of favourable outcome for patients with degenerative lumbosacral disorder undergoing spinal surgery. Another model would investigate the correlation of a simple VAS score with the lengthy and sophisticated outcome measures instruments used to monitor outcome of patients postoperatively. The final part of the thesis is to analyze the concept of sagittal balance as the biological factor in terms of its value and compensatory mechanism that affect the outcome of spinal surgery.