The preoperative predictors for subsequent degeneration in L5-S1 disc after long fusion arthrodesis terminating at L5 in patients with adult scoliosis: focus on spinopelvic parameters

Abstract

BackgroundThe subsequent L5-S1 disc degeneration associated with long fusion arthrodesis terminating at L5 in patients with adult scoliosis has been a common concern. However, few studies paid attention to its preoperative predictors, especially in spinopelvic parameters. The purpose of the present study was to clarify the preoperative predictors of subsequent L5-S1 disc degeneration after long fusion arthrodesis terminating at L5 in patients with adult scoliosis on spinopelvic parameters.MethodsIn this retrospective study, we enrolled 67 patients with adult scoliosis, and the patients were divided into disc degeneration group (DD) and no disc degeneration group (NDD), based on the presence or absence of subsequent L5-S1 disc degeneration. The status of L5-S1 disc was evaluated by a modified version of radiographic classification. Characteristics and spinopelvic parameters of preoperative patients were collected as potential predictors for subsequent lumbosacral disc degeneration after long fusion arthrodesis terminating at L5 in patients with adult scoliosis. Multivariate logistic regression analysis and the receiver operating characteristic curve were used to identify the preoperative predictors, with an adjusted odds ratio (OR) and 95% confidence intervals (CI).ResultsThirty-six patients (53.73%) with subsequent L5-S1 disc degeneration were divided into group DD (preoperative score 0.81 ± 0.57, last follow-up score 1.83 ± 0.60, P < 0.001), and the other 31 patients were divided into group NDD (preoperative and last follow-up score 0.87 ± 0.49). There was no statistical difference in preoperative score (P = 0.583) of lumbosacral disc between two groups; however, significant statistical difference showed in last follow-up score (P < 0.001). Multivariate logistic regression identified three preoperative predictors: pelvic incidence (PI) (P = 0.018), sagittal vertical axis (SVA) (P = 0.024), and sacrum-femoral distance (SFD) (P = 0.023). PI < 48.5° (OR = 0.911, 95% CI = 0.843–0.984), SVA > 4.43 cm (OR = 1.308, 95% CI = 1.036–1.649), and SFD > 5.65 cm (OR = 1.337, 95% CI = 1.041–1.718) showed satisfied accuracy for predicting subsequent L5-S1 disc degeneration.ConclusionThe prevalence of the subsequent L5-S1 disc degeneration after long fusion arthrodesis terminating at L5 in patients with adult scoliosis was 57.3% (36 of 67 patients). PI < 48.5°, SVA > 4.43 cm, and SFD > 5.65 cm were preoperative predictors for the subsequent L5-S1 disc degeneration. More attention should be paid to prevent the L5-S1 disc from degeneration when these preoperative predictors exist, especially with two or more.

Ventajas de la integridad biomecánica sacra durante la fusión lumbar y toracolumbar en pacientes sin patología del segmento L5-S1

“…Se debe prestar más atención para prevenir la degeneración L5-S1 cuando existen estos predictores preoperatorios, especialmente con dos o más. 21 En caso de realizar una fusión dinámica posterior con cajas intersomáticas con cajas rectangulares, la lordosis lumbar y la lordosis segmentaria de los segmentos fusionados disminuyen; el equilibrio sagital se mantiene mediante cambios compensatorios de la inclinación sacra. Las cajas en forma de cuña aumentan significativamente la lordosis segmentaria, mejoran la lordosis lumbar y, por lo tanto, deben ser preferidas para restaurar la alineación sagital en procedimientos instrumentados de fusión intersomática lumbar posterior.…”

Incidence and Risk Factors for L5-S1 Complications After Long-level Floating Fusion in Adult Degenerative Scoliosis

“…Previous studies have assessed radiographic parameters, clinical outcomes, postoperative complications, and revision surgery resulting from subsequent L5-S1 disc degeneration [9]. However, no studies have discussed separately the patient-and surgical-related risk factors for subsequent L5-S1 complications after long-level spinal arthrodesis terminating at L5 in patients with ADS.…”

Predicting factors of adjacent segment degeneration after long-segment spinal fusion: spinopelvic parameters analysis

“…Various studies have proposed risk factors for ASD after short segmental fusion, including the aging process, sagittal imbalance after lumbar fusion and iatrogenic sacrifice of posterior ligament complex during decompression 2,3 . Sagittal plane imbalance on reconstructive spine surgery has become popular and is an increasingly recognized cause of postoperative back pain [4][5][6][7] . The key concept is that normal sagittal alignment helps individuals remain in a stable posture with less energy consumption.…”