The Effect of L5-S1 Degenerative Disc Disease on Outcomes of L4-L5 Fusion

Abstract

Objective: The aim was to investigate the clinical relevance of preoperative caudal adjacent segment degeneration (ASD) in patients undergoing isolated L4-5 fusion to determine a threshold of degeneration at which a primary L4-S1 fusion would be warranted.Summary of Background Data: Increased motion and biomechanical forces across the adjacent caudal segment in isolated L4-L5 fusion leads to concerns regarding the increased incidence of revision surgery because of the development of ASD.Methods: Patients who underwent isolated L4-L5 fusion between 2014 and 2019 were reviewed. Pfirrmann grading and the disc heights of the caudal level relative to the rostral level were used to quantify preoperative adjacent degenerative disc disease. To assess the influence of preoperative caudal degenerative disc disease, preoperative disc height ratios (DHRs) were compared for patients who reported minimal, moderate, and severe Oswestry disability index (ODI) sores on postoperative assessment. For each patient-reported outcome measure (PROM), adjacent DDD was compared for those who did and did not meet MCID. An area under curve analysis was used to identify a threshold of degeneration impacting outcomes from the preoperative DHR.Results: A total of 123 patients were studied with an average follow-up of 2.11 years. All patients demonstrated a significant improvement in all PROMs after surgery. When categorizing patients based on the severity of postoperative ODI scores, there were no preoperative differences in the L5-S1 Pfirrmann grading or DHRs. There was a significant association between greater preoperative anterior DHR and an increased number patients who met MCID for visual analog scale back. There were no radiographic differences in preoperative L5-S1 Pfirrmann grade or DHR for ODI, visual analog scale leg, MCS-12, or PCS-12. area under curve analysis was not able to identify a preoperative DHR threshold that reflected worse MCID for any PROM. Conclusion:No preoperative radiographic indicators of caudal ASD were predictive of worse clinical outcomes after isolated L4-5 fusion.

A Correlation Study of Preoperative Lumbar Paraspinal Muscle Quality and L5-S1 Lumbar Foraminal Stenosis Degeneration after L4-5 TLIF

“…35,36 However, the presence of preoperative disc degeneration did not show a signi cant correlation with the development of postoperative ASD. 37 A study on the degenerative stenosis of the L3-4 intervertebral foramen after L4-5 TLIF surgery can be further investigated.…”

A correlation study of preoperative lumbar paraspinal muscle quality and L5-S1 lumbar foraminal stenosis degeneration after L4–5 TLIF

“…The disc of L5-S1 is also more prone to degeneration in lumbar fusion and LBP patients [ 34 , 35 ]. However, the presence of preoperative disc degeneration did not show a significant correlation with the development of postoperative ASD [ 36 ]. A study on the degenerative stenosis of the L3–4 intervertebral foramen after L4–5 TLIF surgery can be further investigated.…”

The Fate of Pre-Existing L5-S1 Degeneration following Oblique Lumbar Interbody Fusion of L4-L5 and Above

“…Our logistic regression analysis also showed that preoperative disc degeneration of Pfirrmann grades IV and V was significantly associated with symptomatic ASD after OLIF at the L4-L5 level and above. However, Conaway et al reported that preoperative disc height ratio and Pfirrmann grading of the L5-S1 level was not predictive of worse clinical outcomes after isolated L4-L5 fusion [34]. This discrepancy could be explained by the distinct degenerative and kinematic properties of the L5-S1 segment compared to the upper lumbar motion segments, which result in re-stabilization in the advanced degeneration of intervertebral disc and facet joints [30,34].…”

“…However, Conaway et al reported that preoperative disc height ratio and Pfirrmann grading of the L5-S1 level was not predictive of worse clinical outcomes after isolated L4-L5 fusion [34]. This discrepancy could be explained by the distinct degenerative and kinematic properties of the L5-S1 segment compared to the upper lumbar motion segments, which result in re-stabilization in the advanced degeneration of intervertebral disc and facet joints [30,34]. Our results also showed that anterior and posterior disc height were not significant risk factors for symptomatic ASD at the L5-S1 level (Table S1).…”