Correlation between sagittal plane changes and adjacent segment degeneration following lumbar spine fusion

Abstract

IntroductionAdjacent segment degeneration (ASD) has been reported by many authors following lumbar and lumbosacral fusions [1,5,7,9,13,19,21,23,24,26,30,31,32]. In this study the term ASD is used to refer to the onset of degenerative changes in the previously normal disc spaces adjacent to the fusion segment. This becomes symptomatic in many cases and may need re-operation. It is well known that re-operations following lumbar fusions do not always carry good results and that the percentage of good results decreases with each revision surgery [4,11,16]. It is therefore essential to minimize the possibility of re-operation as much as possible. The reasons for adjacent segment degeneration are not fully understood as yet, although various causes have been speculated. The aim of this study is to examine the association of sagittal plane alterations with ASD.Abstract Adjacent segment degeneration following lumbar spine fusion remains a widely acknowledged problem, but there is insufficient knowledge regarding the factors that contribute to its occurrence. The aim of this study is to analyse the relationship between abnormal sagittal plane configuration of the lumbar spine and the development of adjacent segment degeneration. Eightythree consecutive patients who underwent lumbar fusion for degenerative disc disease were reviewed retrospectively. Patients with spondylolytic spondylolisthesis and degenerative scoliosis were not included in this study. Mean follow-up period was 5 years. Results were analysed to determine the association between abnormal sagittal configuration and post operative adjacent segment degeneration. Thirty-one out of 83 patients (36.1%) showed radiographic evidence of adjacent segment degeneration. Patients with normal C7 plumb line and normal sacral inclination in the immediate post operative radiographs had the lowest incidence of adjacent level change compared with patients who had abnormality in one or both of these parameters. The difference was statistically significant (P<0.02). There was no statistically significant difference in the incidence of adjacent level degeneration between male and female patients; between posterior fusion alone and combined posterolateral and posterior interbody fusions; and between fusions extending down to the sacrum and fusions stopping short of the sacrum. It was concluded was that normality of sacral inclination is an important parameter for minimizing the incidence of adjacent level degeneration. Retrolisthesis was the most common type of adjacent segment change. Patients with post operative sagittal plane abnormalities should preferably be followed-up for at least 5 years to detect adjacent level changes.

Does Wallis implant reduce adjacent segment degeneration above lumbosacral instrumented fusion?

“…The radiographic criteria for ASD in the cephalad segment above to instrumentation were the development of olisthesis, disc collapse, increased segmental range of motion (ROM), deterioration ([grade II) of modified UCLA arthritic grade (Table 1) [15,19,30,33,47].…”

“…Adjacent segment degeneration describes nearly any abnormal process that develops in the mobile segment next to a spinal fusion and although the exact mechanism remains uncertain, altered biomechanical stresses (hypermobility, olisthesis, disc height (DH) loss, instability) appear to play a key role in its development [4,16,19,30,33,34,39,47]. Although several clinical and radiological criteria have been introduced to define segmental spinal instability there is no consensus as regard its definition.…”

“…Although most often the criteria to determine ASD are based solely on radiographic findings [2,7,19,28,30,34,39,41,59] reporting an ASD incidence ranging from 8 to 100%, the symptomatic incidence of ASD is significantly lower ranging from 5.2 to 18.5% [7,28,31], while the rate of re-operation rate for symptomatic ASD ranges from 2.7 to 20% [16,58].…”

Compensatory mechanisms contributing to keep the sagittal balance of the spine

“…Recent studies support the idea that analysis of sagittal balance is a crucial keypoint to optimize the management of lumbar degenerative diseases, especially when spinal instrumentation is intended [7,13,15,16].…”

Do position and size matter? An analysis of cage and placement variables for optimum lordosis in PLIF reconstruction

“…The importance of normal sagittal alignment has been increasingly recognised in multi-segmental fusions for spinal deformity [1][2][3]. With increasing focus on patient-related outcomes, there is mounting evidence that optimum sagittal alignment in lumbar fusion is associated with improved outcomes across differing pathologies [1,[4][5][6][7][8][9], reduced post-surgical pain [1-3, 5-8, 10-13], reduced adjacent segment degeneration [4,5,7,[9][10][11][12][13][14], and reduced revision rates [1-5, 7, 9-11, 13, 15-18].…”