Due to the aging population, degenerative scoliosis is a growing clinical problem. It is associated with back pain and radicular symptoms. The pathogenesis of degenerative scoliosis lies in degenerative changes of the spinal structures, such as the intervertebral disc, the facet joints and the vertebrae itself. Possibly muscle weakness also plays a role. However, it is not clear what exactly causes the decompensation to occur and what determines the direction of the curve. It is known that in the normal spine a pre-existing rotation exists at the thoracic level, but not at the lumbar level. In this retrospective study we have investigated if a predominant curve pattern can be found in degenerative scoliosis and whether symptoms are predominantly present at one side relative to the curve direction. The lumbar curves of 88 patients with degenerative scoliosis were analyzed and symptoms were recorded. It was found that curve direction depended significantly on the apical level of the curve. The majority of curves with an apex above L2 were convex to the right, whereas curves with an apex below L2 were more frequently convex to the left. This would indicate that also in degenerative scoliosis the innate curvature and rotational pattern of the spine plays a role in the direction of the curve. Unilateral symptoms were not coupled to the curve direction. It is believed that the symptoms are related to local and more specific degenerative changes besides the scoliotic curve itself.

The Burkus classification system was classified as most reliable in this, but showed only moderate interobserver agreement. Therefore, the need for a more reliable classification system for the radiographic assessment of lumbar interbody fusion still exists to date.

Study Design: Retrospective cohort study. Objective: The current study was undertaken to determine the midterm and long-term radiological outcomes, complications and functional status of patients who underwent a single-level anterior interbody lumbar fusion (ALIF) procedure. Summary of Background Data: Low back pain affects 70%-90% of the general population at some point in their life, and in general, the majority are best treated by nonsurgical therapy. However, a lumbar fusion can be considered in selected cases. In previous decades, lumbar interbody fusion procedures have gained popularity. Despite the approach used, stand-alone interbody fusion is becoming less popular due to poor fusion rates. When studying ALIF procedures, the addition of instrumentation results in higher fusion rates. Nevertheless, long-term follow-up can give either unexpected or similar insights into certain procedures that should be available in the current literature. Therefore, the current study was undertaken to determine the midterm and long-term radiological outcomes, complications, and functional status of patients who underwent a single-level ALIF procedure. Methods: A cohort of 50 patients was studied following stand-alone ALIF for midterm and long-term follow-up of 6.6 years and 19.7 years, respectively. Primary outcome measurements were disability using the Oswestry Disability Index (ODI) score and pain scores using the visual analog scale, and the MOS 36-item Short-Form Health Survey (SF-36) was used to evaluate the quality of life. In addition, radiographic assessment was performed to indicate the number of solid fusions. Results: After a mean of 19.7 years, we had a loss to follow-up of 34%. Functional measurements revealed an ODI of 41 for both time points and an SF-36 physical component score around 41.4 and 40.8 for the midterm and longterm follow-up, respectively. The mental component of the SF-36 was 48.7 and 49.9, respectively. The assessment of interbody fusion revealed only 66% and 70% solid fusion after 6.6 years and 19.7 years, respectively. Conclusions: In concordance with previous studies, the outcome of midterm and long-term results in this study showed that the I/F cage in ALIF procedures is a safe treatment option for single-level interbody fusion. The radiological results corroborate literature regarding stand-alone interbody fusion, and additional instrumentation is likely to increase fusion rates. However, functional measurements reveal that the postsurgical situation remains likely worse than patients in a healthy Dutch population but possibly better that in a back pain population.