Recovery kinetics following spinal deformity correction: a comparison of isolated cervical, thoracolumbar, and combined deformity morphometries.

BACKGROUND CONTEXT: The postoperative recovery patterns of cervical deformity patients, thoracolumbar deformity patients, and patients with combined cervical and thoracolumbar deformities, all relative to one another, is not well understood. Clear objective benchmarks are needed to quantitatively define a "good" versus a "bad" postoperative recovery across multiple follow-up visits, varying deformity types, and guide expectations. PURPOSE: To objectively define and compare the complete 2-year postoperative recovery process among operative cervical only, thoracolumbar only, and combined deformity patients using area-under-the-curve (AUC) methodology. STUDY DESIGN/SETTING: Retrospective review of 2 prospective, multicenter adult cervical and spinal deformity databases. PATIENT SAMPLE: One hundred seventy spinal deformity patients. OUTCOME MEASURES: Common health-related quality of life (HRQOL) assessments across both databases included the EuroQol 5-Dimension Questionnaire and Numeric Rating Scale (NRS) back pain assessment. In order to compare disability improvements, the Neck Disability Index (NDI) and the Oswestry Disability Index (ODI) were merged into one outcome variable, the ODI-NDI. Both assessments are gauged on the same scale, with minimal question deviation. Sagittal Radiographic Alignment was also assessed at pre- and all postoperative time points. METHODS: Operative deformity patients >18 years old with baseline (BL) to 2-year HRQOLs were included. Patients were stratified by cervical only (C), thoracolumbar only (T), and combined deformities (CT). HRQOL and radiographic outcomes were compared within and between deformity groups. AUC normalization generated normalized HRQOL scores at BL and all follow-up intervals (6 weeks, 3 months, 1 year, and 2 year). Normalized scores were plotted against follow-up time interval. AUC was calculated for each follow-up interval, and total area was divided by cumulative follow-up length, determining overall, time-adjusted HRQOL recovery (Integrated Health State, IHS). Multiple linear regression models determined significant predictors of HRQOL discrepancies among deformity groups. RESULTS: One hundred seventy patients were included (27 C, 27 T, and 116 CT). Age, BMI, sex, smoking status, osteoporosis, depression, and BL HRQOL scores were similar among groups (p >. 05). T and CT patients had higher comorbidity severities (CCI: C 0.696, T 1.815, CT 1.699, p = .020). Posterior surgical approaches were most common (62.9%) followed by combined (28.8%) and anterior (6.5%). Standard HRQOL analysis found no significant differences among groups until 1-year follow-up, where C patients exhibited comparatively greater NRS back pain (4.88 vs. 3.65 vs. 3.28, p = .028). NRS Back pain differences between groups subsided by 2-years (p>.05). Despite C patients exhibiting significantly faster ODI-NDI minimal clinically important difference (MCID) achievement (33.3% vs. 0% vs. 23.0%, p < .001), all deformity groups exhibited similar ODI-NDI MCID achievement by 2-years (51.9% vs. 59.3% vs. 62.9%, p = 0.563). After HRQOL normalization, similar results were observed relative to the standard analysis (1-year NRS Back: C 1.17 vs. T 0.50 vs. CT 0.51, p < .001; 2-year NRS Back: 1.20 vs. 0.51 vs. 0.69, p = .060). C patients exhibited a worse NRS back normalized IHS (C 1.18 vs. T 0.58 vs. CT 0.63, p = .004), indicating C patients were in a greater state of postoperative back pain for a longer amount of time. Linear regression models determined postoperative distal junctional kyphosis (adjusted beta: 0.207, p = .039) and osteoporosis (adjusted beta: 0.269, p = .007) as the strongest predictors of a poor NRS back IHS (model summary: R2 = 0.177, p = .039). CONCLUSIONS: Despite C patients exhibiting a quicker rate of MCID disability (ODI-NDI) improvement, they exhibited a poorer overall recovery of back pain with worse NRS back scores compared with BL status and other deformity groups. Postoperative distal junctional kyphosis and osteoporosis were identified as primary drivers of a poor postoperative NRS back IHS. Utilization of the IHS, a single number adjusting for all postoperative HRQOL visits, in conjunction with predictive modelling may pose as an improved method of gauging the effect of surgical details and complications on a patient's entire recovery process.

Recovery Kinetics: Comparison of Patients Undergoing Primary or Revision Procedures for Adult Cervical Deformity Using a Novel Area Under the Curve Methodology.

BACKGROUND: Limited data are available to objectively define what constitutes a "good" versus a "bad" recovery for operative cervical deformity (CD) patients. Furthermore, the recovery patterns of primary versus revision procedures for CD is poorly understood. OBJECTIVE: To define and compare the recovery profiles of CD patients undergoing primary or revision procedures, utilizing a novel area-under-the-curve normalization methodology. METHODS: CD patients undergoing primary or revision surgery with baseline to 1-yr health-related quality of life (HRQL) scores were included. Clinical symptoms and HRQL were compared among groups (primary/revision). Normalized HRQL scores at baseline and follow-up intervals (3M, 6M, 1Y) were generated. Normalized HRQLs were plotted and area under the curve was calculated, generating one number describing overall recovery (Integrated Health State). Subanalysis identified recovery patterns through 2-yr follow-up. RESULTS: Eighty-three patients were included (45 primary, 38 revision). Age (61.3 vs 61.9), gender (F: 66.7% vs 63.2%), body mass index (27.7 vs 29.3), Charlson Comorbidity Index, frailty, and osteoporosis (20% vs 13.2%) were similar between groups (P > .05). Primary patients were more preoperatively neurologically symptomatic (55.6% vs 31.6%), less sagittally malaligned (cervical sagittal vertical axis [cSVA]: 32.6 vs 46.6; T1 slope: 28.8 vs 36.8), underwent more anterior-only approaches (28.9% vs 7.9%), and less posterior-only approaches (37.8% vs 60.5%), all P < .05. Combined approaches, decompressions, osteotomies, and construct length were similar between groups (P > .05). Revisions had longer op-times (438.0 vs 734.4 min, P = .008). Following surgery, complication rate was similar between groups (66.6% vs 65.8%, P = .569). Revision patients remained more malaligned (cSVA, TS-CL; P < .05) than primary patients until 1-yr follow-up (P > .05). Normalized HRQLs determined primary patients to exhibit less neck pain (numeric rating scale [NRS]) and myelopathy (modified Japanese Orthopaedic Association) symptoms through 1-yr follow-up compared to revision patients (P < .05). These differences subsided when following patients through 2 yr (P > .05). Despite similar 2-yr HRQL outcomes, revision patients exhibited worse neck pain (NRS) Integrated Health State recovery (P < .05). CONCLUSION: Despite both primary and revision patients exhibiting similar HRQL outcomes at final follow-up, revision patients were in a greater state of postoperative neck pain for a greater amount of time.

Recovery Kinetics of Radiographic and Implant-Related Revision Patients Following Adult Spinal Deformity Surgery.

BACKGROUND: Prior studies have observed similar health-related quality of life (HRQL) in revisions and nonrevision (NR) patients following adult spinal deformity (ASD) correction. However, a novel comparison approach may allow better comparisons in spine outcomes groups. OBJECTIVE: To determine if ASD revisions for radiographic and implant-related complications undergo a different recovery than NR patients. METHODS: Inclusion: ASD patients with complete HRQL (Oswestry Disability Index, Short-Form-36 version 2 (SF-36), Scoliosis Research Society [SRS]-22) at baseline, 6 wk, 1 yr, 2 yr. Generated revision groups: nonrevision (NR), revised-complete data (RC; with follow-up 2 yr after revision), and revised-incomplete data (RI; without 2-yr follow-up after revision). In a traditional analysis, analysis of variance (ANOVA) compared baseline HRQLs to follow-up changes. In a novel approach, integrated health state was normalized at baseline using area under curve analysis before ANOVA t-tests compared follow-up statuses. RESULTS: Two hundred fifty-eight patients were included with 50 undergoing reoperations (19.4%). Rod fractures (n = 15) and proximal joint kyphosis (n = 9) were most common. In standard HRQL analysis, comparing RC index surgery and RC revision surgery HRQLS revealed no significant differences throughout the 2-yr follow-up from either the initial index or revision procedure. Using normalized HRQL/integrated health state, RI displayed worse scores in SF-36 Physical Component Score, SRS activity, and SRS appearance relative to NR (P < .05), indicating less improvement over the 2-yr period. RC were significantly worse than RI in SF-36 Mental Component Score, SRS mental, SRS satisfaction, and SRS total (P < .05). CONCLUSION: ASD patients indicated for revisions for radiographic and implant-related complications differ significantly in their overall 2-yr recovery compared to NR, using a normalized integrated health state method. Traditional methods for analyzing revision patients' recovery kinetics may overlook delayed improvements.

Recovery following adult spinal deformity surgery: the effect of complications and reoperation in 149 patients with 2-year follow-up.

PURPOSE: To identify the effect of complications and reoperation on the recovery process following adult spinal deformity (ASD) surgery by examining health-related quality of life (HRQOL) measures over time via an integrated health state analysis (IHS). METHODS: A retrospective review of a multicenter, prospective ASD database was conducted. Complication number, type, and need for reoperation (REOP) or not (NOREOP) were recorded. Patients were stratified as having no complication (NOCOMP), any complication (COMP), only minor complications (MINOR) and any major complications (MAJOR). HRQOL measures included Oswestry Disability Index (ODI), Short Form-36 (SF-36), and Scoliosis Research Society-22 (SRS22) at baseline, 6 weeks, 1 and 2 years postoperatively. All HRQOL scores were normalized to each patient's baseline scores and an IHS was then calculated. RESULTS: 149 patients were included. COMP, MINOR, and MAJOR had significantly lower normalized SRS mental scores at 1 and 2 years than NOCOMP (p < 0.05). REOP had significantly worse normalized 1 and 2 year mental component score (MCS), SRS mental, and total score than NOCOMP (p < 0.05). COMP, MINOR, and MAJOR all had significantly lower SRS mental IHSs than NOCOMP (p < 0.05). REOP had significantly lower IHSs for MCS and SRS satisfaction than NOREOP (p < 0.05). REOP had a significantly lower MCS and SRS mental IHS than NOCOMP (p < 0.05). CONCLUSION: An IHS analysis suggests there was a significantly protracted mental recovery phase associated with patients that had at least one complication, as well as either a minor and major complication. The addition of a reoperation also adversely affected the mental recovery as well as overall satisfaction.

Postoperative Recovery After Adult Spinal Deformity Surgery: Comparative Analysis of Age in 149 Patients During 2-year Follow-up.

STUDY DESIGN: Retrospective review of a multicenter, prospective adult spinal deformity (ASD) database. OBJECTIVE: We hypothesized that increased age and increased preoperative disability would negatively impact both the length of time needed to achieve maximal recovery and the amount of functional improvement achieved. In order to gauge the recovery process, a normalization process was used to calculate an integrated health state (IHS) during the 2-year postoperative period. SUMMARY OF BACKGROUND DATA: Elderly patients with ASD generally have worse baseline health-related quality of life (HRQOL) measures than younger patients. Current methods of reporting outcomes are limited, perhaps diminishing the health impact of the entire postoperative recovery experience. METHODS: Inclusion criteria included 18 or more years and ASD. Patient groups: young (≤45 yr), middle (46-64), elderly (≥65) as well as by baseline Oswestry Disability Index (ODI) scores: MILD (0-30), MEDIUM (31-49), and HIGH (≥50). Collected HRQOL measures included ODI, Short Form-36(PCS/MCS), and Scoliosis Research Society-22 (SRS22) at baseline, 6 weeks, 1, and 2-year postoperative. All HRQOL measures were normalized to each patient's baseline scores. A 2-year IHS was calculated for each individual patient and the means were compared between groups. RESULTS: 149 patients were included (≤45:32, 46-64:67, ≥65:50). All groups significantly improved in all HRQOL at 2-year compared with baseline (P < 0.05) except for MCS, ODI, and SRS activity for the 45 or less group (P > 0.05). Normalized IHS HRQOL for young patients was worse than elderly for ODI, PCS, MCS, SRS activity, pain and total during the 2-year recovery period from index surgery. The MILD ODI group had significantly worse 2-year IHS values than the HIGH group for all HRQOL measured (P < 0.05) except SRS appearance and satisfaction (P > 0.05). CONCLUSION: Contrary to our hypothesis, an IHS analysis suggested that the recovery process was significantly better for elderly patients than young patients and better for patients with high baseline disability. LEVEL OF EVIDENCE: 3.

Preliminary biomechanical proof of concept for a hybrid locking plate/variable pitch screw construct for anterior fixation of type II odontoid fractures.

STUDY DESIGN: A human cadaveric biomechanical proof-of-concept study. OBJECTIVE: To test whether adding a locking plate to the anterior surface of C2 attaching directly to the interfragmentary screw may reduce potential for anterior screw cutout and improve construct strength. SUMMARY OF BACKGROUND DATA: The most common mode of failure for screw fixation of dens fractures is via cutout at the anterior body of C2. METHODS: A human, cadaveric model of type II dens fractures was created and fixed using either a headless, fully threaded variable pitch screw (FTVPS) or a screw with an attachable locking plate construct (LPC). Following quasistatic loading to failure, stiffness and load to failure were compared using t tests. Mode of failure was determined from radiographical and gross inspection. RESULTS: Load to failure was greater for the LPC than for the FTVPS alone (498 N vs. 362 N, P = 0.04). The LPC consistently failed via compression of cancellous bone posterior to the lag screw, whereas the FTVPS constructs failed via cutout of the screw from the anterior C2 body. CONCLUSION: Locking plate supplementation of anterior screw fixation of type II odontoid fractures improves construct strength and changes the failure mechanism from anterior screw cutout to posterior displacement of the screw. An attachable locking plate/interfragmentary screw construct may improve clinical outcomes for these fractures.