Selecting caudal fusion levels: 2 year functional and stiffness outcomes with matched pairs analysis in multilevel fusion to L5 versus S1.

PURPOSE: Controversy persists as to whether to end multilevel thoracolumbar fusions caudally at L5 or S1. Some argue that stopping at L5 may preserve greater function, but there are few data comparing functional limitations due to lumbar stiffness in patients with fusion to L5 versus S1. The aim of this study was to evaluate whether patients undergoing multilevel thoracolumbar fusions with an L5 caudal endpoint have a better lumbosacral function than patients with an S1 caudal endpoint. METHODS: Patients undergoing successful thoracolumbar fusion of 5 or more levels to L5 or S1, with solid fusion at 2 year follow-up, were examined from a single European center in addition to a multi-center North American database of 237 patients. In total, 40 patients with a distal stopping point of L5 were matched with a subset of 40 patients with a distal endpoint of S1 ± pelvic fixation. The L5 and S1 groups were matched for the final Oswestry Disability Index (ODI), Sagittal Vertical Axis (SVA C7-S1), number of fusion levels, and age. Impacts of lumbar stiffness on function as measured by the Lumbar Stiffness Disability Index (LSDI) were compared using the conditional logistic regression. RESULTS: After matching, there was no significant difference between the S1 and L5 groups for the final ODI (29.22 ± 21.6 for S1 versus 29.21 ± 21.7 for L5; p = 0.98), SVA (29.5 ± 40.3 mm for S1 versus 33.7 ± 37.1 mm for L5; p = 0.97), mean age (61.6 ± 11.0 years for S1 versus 58.3 ± 12.6 years for L5; p = 0.23), and number of fusion levels (9.7 ± 3.3 levels for S1 versus 9.0 ± 3 levels for L5; p = 0.34). The final 2-year postoperative LSDI scores were not significantly different between the S1 group (28.08 ± 21.47) and L5 group (29.21 ± 21.66) (hazard ratio 0.99, 95 % CI 0.97-1.03, p = 0.81). CONCLUSION: The analysis of patients with multilevel thoracolumbar fusions demonstrated that after minimum 2 year follow-up, self-reported functional impacts of lumbar stiffness were not significantly different between the patients with distal endpoints of L5 versus S1. The choice of distal fusion level of L5 does not appear to retain sufficient spinal flexibility to substantially affect postoperative function. LEVEL OF EVIDENCE: Level III.

The Health Impact of Adult Cervical Deformity in Patients Presenting for Surgical Treatment: Comparison to United States Population Norms and Chronic Disease States Based on the EuroQuol-5 Dimensions Questionnaire.

BACKGROUND: Although adult cervical spine deformity (ACSD) is associated with pain and disability, its health impact has not been quantified in comparison to other chronic diseases. OBJECTIVE: To perform a comparative analysis of the health impact of symptomatic ACSD to US normative and chronic disease values using EQ-5D (EuroQuol-5 Dimensions questionnaire) scores. METHODS: ACSD patients presenting for surgical treatment were identified from a prospectively collected multicenter database. Baseline demographics and EQ-5D scores were collected and compared with US normative and disease state values. RESULTS: Of 121 ACSD patients, 115 (95%) completed the EQ-5D (60% women, mean age 61 years, previous spine surgery in 44%). Diagnoses included kyphosis with mid-cervical (63.4%), cervico-thoracic (23.5%), or thoracic (8.7%) apex and primary coronal deformity (4.3%). The mean ACSD EQ-5D index was 0.511 (standard definition = 0.224), which is 34% below the bottom 25th percentile (0.780) for similar age- and gender-matched US normative populations. Mean ACSD EQ-5D index values were worse than the bottom 25th percentile for several other disease states, including chronic ischemic heart disease (0.708), malignant breast cancer (0.708), and malignant prostate cancer (0.708). ACSD mean index values were comparable to the bottom 25th percentile values for blindness/low vision (0.543), emphysema (0.508), renal failure (0.506), and stroke (0.463). EQ-5D scores did not significantly differ based on cervical deformity type ( P = .66). CONCLUSION: The health impact of symptomatic ACSD is substantial, with negative impact across all EQ-5D domains. The mean ACSD EQ-5D index was comparable to the bottom 25th percentile values for blindness/low vision, emphysema, renal failure, and stroke.