Faculty Bibliography

OBJECTIVE:Adult cervical deformity (ACD) has high complication rates due to surgical complexity and patient frailty. Very few studies have focused on longer-term outcomes of operative ACD treatment. The objective of this study was to assess minimum 2-year outcomes and complications of ACD surgery. METHODS:A multicenter, prospective observational study was performed at 13 centers across the United States to evaluate surgical outcomes for ACD. Demographics, complications, radiographic parameters, and patient-reported outcome measures (PROMs; Neck Disability Index, modified Japanese Orthopaedic Association, EuroQol-5D [EQ-5D], and numeric rating scale [NRS] for neck and back pain) were evaluated, and analyses focused on patients with ≥ 2-year follow-up. RESULTS:Of 169 patients with ACD who were eligible for the study, 102 (60.4%) had a minimum 2-year follow-up (mean 3.4 years, range 2-8.1 years). The mean age at surgery was 62 years (SD 11 years). Surgical approaches included anterior-only (22.8%), posterior-only (39.6%), and combined (37.6%). PROMs significantly improved from baseline to last follow-up, including Neck Disability Index (from 47.3 to 33.0) and modified Japanese Orthopaedic Association score (from 12.0 to 12.8; for patients with baseline score ≤ 14), neck pain NRS (from 6.8 to 3.8), back pain NRS (from 5.5 to 4.8), EQ-5D score (from 0.74 to 0.78), and EQ-5D visual analog scale score (from 59.5 to 66.6) (all p ≤ 0.04). More than half of the patients (n = 58, 56.9%) had at least one complication, with the most common complications including dysphagia, distal junctional kyphosis, instrumentation failure, and cardiopulmonary events. The patients who did not achieve 2-year follow-up (n = 67) were similar to study patients based on baseline demographics, comorbidities, and PROMs. Over the course of follow-up, 23 of the total 169 enrolled patients were reported to have died. Notably, these represent all-cause mortalities during the course of follow-up. CONCLUSIONS:This multicenter, prospective analysis demonstrates that operative treatment for ACD provides significant improvement of health-related quality of life at a mean 3.4-year follow-up, despite high complication rates and a high rate of all-cause mortality that is reflective of the overall frailty of this patient population. To the authors' knowledge, this study represents the largest and most comprehensive prospective effort to date designed to assess the intermediate-term outcomes and complications of operative treatment for ACD.

BACKGROUND:Persistent pelvic compensation following adult spinal deformity (ASD) corrective surgery may impair quality of life and result in persistent pathologic lower extremity compensation. Ideal age-specific alignment targets have been proposed to improve surgical outcomes, though it is unclear whether reaching these ideal targets reduces rates of pelvic nonresponse following surgery. Our aim was to assess the relationship between pelvic nonresponse, age-specific alignment, and lower-limb compensation following surgery for ASD. METHODS:Single-center retrospective cohort study. ASD patients were grouped: those who did not improve in Scoliosis Research Society-Schwab pelvic tilt (PT) modifier (pelvic nonresponders [PNR]), and those who improved (pelvic responders [PR]). Groups were propensity score matched for preoperative PT and assessed for differences in spinal and lower extremity alignment. Rates of pelvic nonresponse were compared across patient groups who were undercorrected, overcorrected, or matched age-specific postoperative alignment targets. RESULTS:< 0.05). CONCLUSIONS:For patients with moderate to severe baseline truncal inclination, more aggressive surgical correction relative to ideal age-specific PI-LL was associated with lower rates of pelvic nonresponse. Postoperative alignment targets may need to be adjusted to optimize alignment outcomes for patients with substantial preoperative sagittal deformity. CLINICAL RELEVANCE/CONCLUSIONS:These findings increase our understanding of the poor outcomes that occur despite ideal realignment. Surgical correction of severe global sagittal deformity should be prioritized to mitigate these occurrences. LEVEL OF EVIDENCE: 3/METHODS/:

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVES/OBJECTIVE:Investigate a composite score to evaluate the relationship between alignment proportionality and risk of distal junctional kyphosis (DJK). METHODS:84 patients with minimum 1 year follow-up were included (age = 61.1 ± 10.3 years, 64.3% women). The Cervical Score was constructed using offsets from age-adjusted normative values for sagittal vertical axis (SVA), T1 Slope (TS), and TS minus cervical lordosis (CL). Individual points were assigned based on offset with age-adjusted alignment targets and summed to generate the Cervical Score. Rates of mechanical failure (DJK revision or severe DJK [DJK> 20° and ΔDJK> 10°]) were assessed overall and based on Cervical Score. Logistical regressions assessed associations between early radiographic alignment and 1-year failure rate. RESULTS:Mechanical failure rate was 21.4% (N = 18), 10.7% requiring revision. By multivariate logistical regression: 3-month T1S (OR: .935), TS-CL (OR:0.882), and SVA (OR:1.015) were independent predictors of 1-year failure (all P < .05). Cervical Score ranged (-6 to 6), 37.8% of patients between -1 and 1, and 50.0% with 2 or higher. DJK patients had significantly higher Cervical Score (4.1 ± 1.3 vs .6 ± 2.2, P < .001). Patients with a score ≥3 were significantly more likely to develop a failure (71.4%) with OR of 38.55 (95%CI [7.73; 192.26]) and Nagelkerke r2 .524 (P < .001). CONCLUSION/CONCLUSIONS:This study developed a composite alignment score predictive of mechanical failures in CD surgery. A score ≥3 at 3 months following surgery was associated with a marked increase in failure rate. The Cervical Score can be used to analyze sagittal alignment and help define realignment objectives to reduce mechanical failure.

OBJECTIVE:The current literature has primarily focused on the 2-year outcomes of operative adult spinal deformity (ASD) treatment. Longer term durability is important given the invasiveness, complications, and costs of these procedures. The aim of this study was to assess minimum 3-year outcomes and complications of ASD surgery. METHODS:Operatively treated ASD patients were assessed at baseline, follow-up, and through mailings. Patient-reported outcome measures (PROMs) included scores on the Oswestry Disability Index (ODI), Scoliosis Research Society-22r (SRS-22r) questionnaire, mental component summary (MCS) and physical component summary (PCS) of the SF-36, and numeric rating scale (NRS) for back and leg pain. Complications were classified as perioperative (≤ 90 days), delayed (90 days to 2 years), and long term (≥ 2 years). Analyses focused on patients with minimum 3-year follow-up. RESULTS:Of 569 patients, 427 (75%) with minimum 3-year follow-up (mean ± SD [range] 4.1 ± 1.1 [3.0-9.6] years) had a mean age of 60.8 years and 75% were women. Operative treatment included a posterior approach for 426 patients (99%), with a mean ± SD 12 ± 4 fusion levels. Anterior lumbar interbody fusion was performed in 35 (8%) patients, and 89 (21%) underwent 3-column osteotomy. All PROMs improved significantly from baseline to last follow-up, including scores on ODI (45.4 to 30.5), PCS (31.0 to 38.5), MCS (45.3 to 50.6), SRS-22r total (2.7 to 3.6), SRS-22r activity (2.8 to 3.5), SRS-22r pain (2.3 to 3.4), SRS-22r appearance (2.4 to 3.5), SRS-22r mental (3.4 to 3.7), SRS-22r satisfaction (2.7 to 4.1), NRS for back pain (7.1 to 3.8), and NRS for leg pain (4.8 to 3.0) (all p < 0.001). Degradations in some outcome measures were observed between the 2-year and last follow-up evaluations, but the magnitudes of these degradations were modest and arguably not clinically significant. Overall, 277 (65%) patients had at least 1 complication, including 185 (43%) perioperative, 118 (27%) delayed, and 56 (13%) long term. Notably, the 142 patients who did not achieve 3-year follow-up were similar to the study patients in terms of demographic characteristics, deformities, and baseline PROMs and had similar rates and types of complications. CONCLUSIONS:This prospective multicenter analysis demonstrated that operative ASD treatment provided significant improvement of health-related quality of life at minimum 3-year follow-up (mean 4.1 years), suggesting that the benefits of surgery for ASD remain durable at longer follow-up. These findings should prove useful for counseling, cost-effectiveness assessments, and efforts to improve the safety of care.

OBJECTIVE:Hyperextension of C0-2 is a debilitating compensatory mechanism used to maintain horizontal gaze, analogous to high pelvic tilt in the lumbopelvic complex to maintain an upright posture. This study aims to investigate the impact of cervical deformity (CD) correction on this hyperextension. The authors hypothesize that correction of cervical sagittal malalignment allows for relaxation of C0-2 hyperextension and improved clinical outcomes. METHODS:A retrospective review was conducted of a multicenter database of patients with CD undergoing spinal realignment and fusion caudal to C2 and cephalad to the pelvis. Range of motion (ROM) and reserve of extension (ROE) were calculated across C2-7 and C0-2. The association between C2-7 correction and change in C0-2 ROE was investigated while controlling for horizontal gaze, followed by stratification into ΔC2-7 percentiles. RESULTS:Sixty-five patients were included (mean age 61.8 ± 9.6 years, 68% female). At baseline, patients had cervical kyphosis (C2-7, -11.7° ± 18.2°; T1 slope-cervical lordosis mismatch, 38.6° ± 18.6°), negative global alignment (sagittal vertical axis [SVA] -12.8 ± 71.2 mm), and hyperlordosis at C0-2 (mean 33.2° ± 11.8°). The mean ROM was 25.7° ± 17.7° and 21.3° ± 9.9° at C2-7 and C0-2, respectively, with an ROE of approximately 9° for each segment. Limited C0-2 ROM and ROE correlated with the Neck Disability Index (r = -0.371 and -0.394, p < 0.01). The mean number of levels fused was 7.0 ± 3.1 (24.6% anterior, 43.1% posterior), with 87.7% undergoing at least an osteotomy. At 1 year, mean C2-7 increased to 5.5° ± 13.4°, SVA became neutral (11.5 ± 54.8 mm), C0-2 hyperlordosis decreased to 27.8° ± 11.7°, and thoracic kyphosis (TK) increased to -49.4° ± 18.1° (all p < 0.001). Concurrently, mean C0-2 ROM increased to 27.6° ± 8.1° and C2-7 ROM decreased significantly to 9.0° ± 12.3° without a change in ROE. Controlling for horizontal gaze, change in C2-7 lordosis significantly correlated with increased TK (r = -0.617, p < 0.001), decreased C0-2 (r = -0.747, p < 0.001), and increased C0-2 ROE (r = 0.550, p = 0.002). CONCLUSIONS:CD correction can significantly impact cephalad and caudal compensation in the upper cervical and thoracic spine. Restoration of cervical alignment resulted in increased C0-2 ROE and TK and was also associated with improved clinical outcome.

STUDY DESIGN/METHODS:Single-center retrospective cohort study. OBJECTIVES/OBJECTIVE:To evaluate inpatient MME administration associated with different lumbar spinal fusion surgeries. METHODS:< .05. RESULTS:= .009). There were no significant differences in MME/hour and incidence of ileus between all groups. CONCLUSION/CONCLUSIONS:Patients undergoing MIS TLIF had lower inpatient opioid intake compared to TP and SP ALIF/LLIF, as well as shorter LOS compared to all groups except SP ALIF/LLIF. Thus, it appears that the advantages of minimally invasive surgery are seen in minimally invasive TLIFs.

PURPOSE/OBJECTIVE:This study compares perioperative and 1-year outcomes of lateral decubitus single position circumferential fusion (L-SPS) versus minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) for degenerative pathologies. METHODS:Multicenter retrospective chart review of patients undergoing AP fusion with L-SPS or MIS TLIF. Demographics and clinical and radiographic outcomes were compared using independent samples t tests and chi-squared analyses with significance set at p < 0.05. RESULTS:A total of 445 patients were included: 353 L-SPS, 92 MIS TLIF. The L-SPS cohort was significantly older with fewer diabetics and more levels fused. The L-SPS cohort had significantly shorter operative time, blood loss, radiation dosage, and length of stay compared to MIS TLIF. 1-year follow-up showed that the L-SPS cohort had higher rates of fusion (97.87% vs. 81.11%; p = 0.006) and lower rates of subsidence (6.38% vs. 38.46%; p < 0.001) compared with MIS TLIF. There were significantly fewer returns to the OR within 1 year for early mechanical failures with L-SPS (0.0% vs. 5.4%; p < 0.001). 1-year radiographic outcomes revealed that the L-SPS cohort had a greater LL (56.6 ± 12.5 vs. 51.1 ± 15.9; p = 0.004), smaller PI-LL mismatch (0.2 ± 13.0 vs. 5.5 ± 10.5; p = 0.004). There were no significant differences in amount of change in VAS scores between cohorts. Similar results were seen after propensity-matched analysis and sub-analysis of cases including L5-S1. CONCLUSIONS:L-SPS improves perioperative outcomes and does not compromise clinical or radiographic results at 1-year follow-up compared with MIS TLIF. There may be decreased rates of early mechanical failure with L-SPS.

STUDY DESIGN/UNASSIGNED:Survey. OBJECTIVES/UNASSIGNED:To characterize national practices of and shortcomings surrounding intraoperative assessments of spinal alignment. METHODS/UNASSIGNED:Spine surgeons in the US were surveyed to analyze their experience with assessing spinal alignment intraoperatively. RESULTS/UNASSIGNED:8.8 years of surgical experience completed the survey. To assess alignment intraoperatively, 84% (91/108) use C-arm or spot radiographs, 40% (43/108) use full-length radiographs, and 20% utilize the T-bar (22/108). 88% of respondents' surgical centers (93/106) possessed a navigation camera and 63% of respondents (68/108) report using surgical navigation for 40% of their deformity cases on average. Reported deterrents for using current technology to assess alignment were workflow interruption (54%, 58/108), expense (33%, 36/108), and added radiation exposure (26%, 28/108). 87% of respondents (82/94) reported a need for improvement in current capabilities of making intraoperative assessments of spinal alignment. CONCLUSIONS/UNASSIGNED:Corrective surgery for spinal deformity is a complex procedure that requires a high level of expertise to perform safely. The majority of surveyed surgeons primarily rely on radiographs for intraoperative assessments of alignment. Despite the majority of surveyed surgical practices possessing navigation cameras, they are utilized only for a minority of spinal deformity cases. With the majority of surveyed surgeons reporting a need for improvement in technology to assess spinal alignment intraoperatively, 3 of the top design considerations should include workflow interruption, expense, and radiation exposure.

STUDY DESIGN/METHODS:This was a retrospective review of a prospectively collected database. OBJECTIVE:The aim of this study was to delineate radiographic parameters that distinguish severe cervical spine deformity (CSD). SUMMARY OF BACKGROUND DATA/BACKGROUND:Our objective was to define parameters that distinguish severe CSD using a consensus approach combined with discriminant analysis as no system currently exists in the literature. METHODS:Twelve CSD surgeons reviewed preoperative x-rays from a CSD database. A consensus was reached for categorizing patients into a severe cervical deformity (sCD), non-severe cervical deformity (non-sCD), or an indeterminate cohort. Radiographic parameters were found including classic cervical and spinopelvic parameters in neutral/flexion/extension alignment. To perform our discriminant analysis, we selected for parameters that had a significant difference between the sCD and non-sCD groups using the Student t test. A discriminant function analysis was used to determine which variables discriminate between the sCD versus non-sCD. A stepwise analysis was performed to build a model of parameters to delineate sCD. RESULTS:A total of 146 patients with cervical deformity were reviewed (60.5±10.5 y; body mass index: 29.8 kg/m2; 61.3% female). There were 83 (56.8%) classified as sCD and 51 (34.9%) as non-sCD. The comparison analysis led to 16 radiographic parameters that were different between cohorts, and 5 parameters discriminated sCD and non-sCD. These parameters were cervical sagittal vertical axis, T1 slope, maximum focal kyphosis in extension, C2 slope in extension, and number of kyphotic levels in extension. The canonical coefficient of correlation was 0.689, demonstrating a strong association between our model and cervical deformity classification. The accuracy of classification was 87.0%, and cross-validation was 85.2% successful. CONCLUSIONS:More than one third of a series of CSD patients were not considered to have a sCD. Analysis of an initial 17 parameters showed that a subset of 5 parameters can discriminate between sCD versus non-sCD with 85% accuracy. Our study demonstrates that flexion/extension images are critical for defining severe CD.

OBJECTIVE:Cervical deformity (CD) is a complex condition with a clear impact on patient quality of life, which can be improved with surgical treatment. Previous study following thoracolumbar surgery demonstrated a spontaneous and maintained improvement in cervical alignment following lumbar pedicle subtraction osteotomy (PSO). In this study the authors aimed to investigate the complementary questions of whether cervical alignment induces a change in global alignment and whether this change stabilizes over time. METHODS:To analyze spontaneous changes, this study included only patients with at least 5 levels remaining unfused following surgery. After data were obtained for the entire cohort, repeated-measures analyses were conducted between preoperative baseline and 3-month and 1-year follow-ups with a post hoc analysis and Bonferroni correction. A subanalysis of patients with 2-year follow-up was performed. RESULTS:One-year follow-up data were available for 121 of 168 patients (72%), and 89 patients had at least 5 levels remaining unfused following surgery. Preoperatively there was a moderate anterior cervical alignment (C2-7, -7.7° [kyphosis]; T1 slope minus cervical lordosis, 37.1°; cervical sagittal vertebral axis [cSVA], 37 mm) combined with a posterior global alignment (SVA, -8 mm) with lumbar hyperextension (pelvic incidence [PI] minus lumbar lordosis [LL] mismatch [PI-LL], -0.6°). Patients underwent a significant correction of the cervical alignment (median ΔC2-7, 13.6°). Simultaneously, PI-LL, T1 pelvic angle (TPA), and SVA increased significantly (all p < 0.05) between baseline and 3-month and 1-year follow-ups. Post hoc analysis demonstrated that all of the changes occurred between baseline and 3 months. Subanalysis of patients with complete 2-year follow-up demonstrated similar results, with stable postoperative thoracolumbar alignment achieved at 3 months. CONCLUSIONS:Correction of cervical malalignment can have a significant impact on thoracolumbar regional and global alignment. Peak relaxation of compensatory mechanisms is achieved by the 3-month follow-up and tends to remain stable. Subanalysis with 2-year data further supports this finding. These findings can help to identify when the results of cervical surgery on global alignment can be best evaluated.