Faculty Bibliography

BACKGROUND CONTEXT: Complications occur commonly following adult spinal deformity surgery. Length of stay may be influenced by the type of surgical intervention, and/or by postoperative complication and the intervention required to treat that complication. PURPOSE: To understand the impact of complications and their intervention severity on the incremental increase in length of stay. STUDY DESIGN/SETTING: Retrospective cohort study of prospective ASD database. PATIENT SAMPLE: The study included 1418 adult spinal deformity patients. OUTCOME MEASURES: Neurologic complications, HRQL scores.
METHOD(S): ASD patients (>18yrs, scoliosis >=20degree, SVA >=5cm, PT >=25degree and/or TK >60degree). Complications were classified based on complication type, and intervention severity (grade 0, no intervention, Grade 1 minimal intervention (medication change, etc), Grade 2 moderate (cardioversion, chest tube, etc), grade 3 major intervention (return to OR).
RESULT(S): Of the 1418 patients included, 901 had at least one complication event, with 568 with a complication before discharge. Three hundred and six had an event that required a reoperation and 275 were readmitted for their event. When determining LOS, a baseline was established that was influenced by the type of surgery and placed into three groups based on osteotomy (O) and interbody use (I); Group 1 (n408): 0% O, 75% I, LOS=7.9, Group 2 (n374): 100% O, 0% I, LOS=11.9, Group 3 (n595) 100% O and I, LOS=11.2. Having a complication event prior to discharge led to an increase of 1-4 days for each group (p<0.01). This was true for every complication, regardless of type, but was worse for renal and pneumonia. The increase in LOS was most driven by the intervention required. No intervention had an LOS of 6.9, Grade 1 +1.2 days, Grade 2, +1.8 days, Grade 3 +2.5 days. Using the sum of a weighted intervention score (SUM=1*#grade1 + 2*#grade2 + 3*#grade3), we can even more accurately predict the incremental increase in LOS. This occurs until a weighted score of 7 which accurately predicts an increase of 7.5 days.
CONCLUSION(S): Length of stay following ASD is predicted by the type of surgical intervention, and postoperative complication profile. Additional days are most predicted by the type of complication and by intervention severity. A weighted intervention score can predict the additional LOS and is useful to help understand the impact of complications. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Prior studies demonstrated that symptomatic adult spinal deformity (SASD) is a heterogeneous condition with varying degrees of negative health impact depending on the specific type and severity of deformity. Currently, there is some controversy regarding the subset of SASD with global coronal malalignment (GCM) and its associated health impact. Moreover, few reports have assessed the health impact of this global coronal parameter in comparison to other deformity types. A comparative study of deformity types with severe global malalignment (eg, severe GCM) may provide clinically relevant insights and identify potential differences in demographics and health impact. PURPOSE: To compare demographics and health impact of SASD patients with severe global malalignment (primary sagittal [SAG-only] vs primary coronal [COR-only] vs sagittal+coronal [MIX]). STUDY DESIGN/SETTING: Retrospective analysis of a prospective multicenter database. PATIENT SAMPLE: Enrollment required age >=18 yrs and one of the following: scoliosis >=20degree, sagittal vertical axis (SVA) >=5cm, pelvic tilt >=25degree, and/or thoracic kyphosis >=60degree. OUTCOME MEASURES: Short Form-36 (SF-36) PCS score.
METHOD(S): Consecutive SASD patients from a prospective multicenter database were evaluated for type and severity of global malalignment. Severe alignment thresholds included SVA >=10cm (SAG-only), GCM >=6cm (COR-only), or both SVA >=10cm and GCM >=6cm (MIX). SF-36 PCS scores were compared with U.S. normative values.
RESULT(S): Of 492 SASD patients that met threshold alignment criteria, 463 (94%) completed the SF-36 and were included (78% women, mean age 65 years, mean BMI 28.6 kg/m2, previous spine surgery in 65%). Deformity types were SAG-only (58%), COR-only (19%) and MIX (23%). COR-only had more women (94%, p<0.001), younger age (61 years, p=0.004), and lower BMI (26 kg/m2, p<0.001). Charlson Comorbity Index (CCI) scores and total number of comorbidities were comparable among the deformity types (p>0.05). All deformity types were 'frail' based on ASD-Frailty Index scores (SAG-only [3.9], COR-only [3.1], MIX [4.0]). Overall mean PCS was lower compared to similar age- and gender-matched U.S. normative values (29.0 vs 45.3, p<0.001). Mean PCS was significantly different between deformity types (p<0.001): SAG-only (28.5) vs COR-only (33.1) vs MIX (27.0). PCS offsets from normative population scores were significantly different between deformity types (p=0.001): SAG-only (-16.6) vs COR-only (-13.4) vs MIX (-18.2).
CONCLUSION(S): Demographic comparisons demonstrated significantly more women, younger age, and lower BMI in the COR-only deformity type. Severe global malalignment (SVA >=10cm and/or GCM >=6cm) had substantial debilitating impact on health, with MIX deformity type (i.e., severe global sagittal and coronal malalignment) experiencing the greatest health impact. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Cervical deformity (CD) severity has been linked to poor quality of life and severe neck pain. However, little is known of the relationship between surgical invasiveness accounting for cervical deformity severity and frailty status. PURPOSE: Investigate the outcomes of CD surgery by invasiveness, frailty status and baseline degree of deformity. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: Ninety-six CD patients. OUTCOME MEASURES: HRQL measurements: NDI, EQ5D, mJOA.
METHOD(S): Inclusion criteria was defined as operative CD patients (C2-C7 Cobb>10degreeor CK>10degree, cSVA>4cm or CBVA>25degree) >18yr with follow up (1-year) radiographic and HRQL scores, NDI, mJOA and EQ5D. Patients were stratified by severity of deformity by TS-CL, categorized by the new-mJOA based modifiers: Low/Mod <45degree (Low-Mod); Severe >45degree(Sev). Frailty scores were calculated based upon the modified CD frailty index by Passias et. Al and categorized into severely frail (SF) >=0.5 and not SF (N-SF)<0.5. Patients were categorized by their frailty and deformity status (Low-Mod/N-SF; Low-Mod/SF; Sev/N-SF; Sev/SF). Logistic regression analysis assessed the relationship between increasing invasiveness and outcomes (DJK, complications). Within the significant frailty/deformity risk groups, decision tree analysis assessed thresholds for an invasiveness severity cut-off point, below which experiencing a reoperation, complication, DJK occurrence and poor mJOA were higher.
RESULT(S): Ninety-six CD patients met inclusion criteria (62.2+/-10.2 years, 66% female, 28.4+/-7.4 kg/m2). By approach: 19.8% anterior-only, 47.9% posterior-only, 32.3% combined (levels fused: 7.7+/-3.9). By deformity severity: 23.7% Low, 40.9% Moderate, 34.4% Severe, while frailty assessment placed 32.3% in N-SF and 67.7% SF. This categorized the patients into deformity/frailty groups as follows: 19.8% Low-Mod/N-SF(19), 13.5%(13) Sev/N-SF, 44.8%(43) Low-Mod/SF, 21.9%(21) Sev/SF. Logistic regression analysis found a significant relationship between increasing deformity severity and occurrence of severe postop DJK(1.053 [1.016-1.093], p= 0.005), complications(1.045 [1.012 - 1.080], p=0.007), revision by 1-year(1.059 [1.000-1.122], p= 0.049). Additionally, increasing invasiveness and occurrence of severe DJK (1.030 [1.007-1.054], p= 0.024) and revision (1.026 [1.008 - 1.044], p=0.005). Invasiveness increased with deformity and frailty severity: 53.6 Low-Mod/N-SF, 81.4 Sev/N-SF, 56.4 Low-Mod/SF, 79.8 Sev/SF; p=0.002. After defining a favorable outcome as no occurrence of severe DJK, no major complications and no revisions, and 1Y mJOA improvement (28.1%), invasiveness scores were compared within deformity/frailty groups between patients who met/did not meet the favorable outcome. For the NSF deformity groups, those with a favorable outcome had larger invasiveness scores (Low-Mod: 58.7 vs 48.5; Sev: 77.7 vs 89.6). For the SF deformity groups, the favorable outcome had significantly lower invasiveness scores for the Low-Mod deformity group (38.1 vs 62.9, p=0.008), while the Sev/SF deformity favorable outcome group remained larger (86.8 vs 79.4), though this was not significant. For the Low-Mod/SF group an invasiveness cutoff score of <48 where achieving a favorable outcome was 3x higher (3.08[1.2-7.9], p=0.019).
CONCLUSION(S): For SF patients, when deformity severity is low to moderate, surgeons may limit the invasiveness of their procedures in order to account for the patient's susceptibility to poor outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: The choice of surgical approach in CD surgery is often dictated by surgeon preference and experience. This choice could significantly impact the costs and outcomes of an operation, therefore the approaches should be analyzed in order to determine the optimal approach from a cost-utility perspective. The cost utility of different surgical approaches in cervical deformity (CD) has not been investigated in the literature. PURPOSE: Investigate the cost utility of differing approaches in operative CD patients. STUDY DESIGN/SETTING: Retrospective review of a prospective multicenter cervical deformity database. PATIENT SAMPLE: A total of 105 CD patients. OUTCOME MEASURES: Costs, EuroQol-5D (EQ-5D), Quality adjusted life years (QALYs), Cost per quality adjusted life years.
METHOD(S): Included CD patients (C2-C7 Cobb>10degreeor CK>10degree, cSVA>4cm or CBVA>25degree) >18yr with follow-up (1-year) surgical and health related quality of life scores. Costs were calculated using the PearlDiver database, which reflects both private insurance and Medicare reimbursement claims. QALYs and cost per QALY were calculated using a 3% discount rate to account for residual decline to life expectancy (78.7 years). After accounting for complications, LOS, revisions, and death, cost per QALY at 1Y and life expectancy [LE] were calculated for surgical approach (anterior-only, posterior-only [excluding PSO and VCR to account for differences in instrumentation], combined). In a subanalysis, approach groups were propensity-score matched for TS-CL to account for baseline (BL) deformity.
RESULT(S): A total of 105 CD patients met inclusion criteria (61.9 yrs, 63% female, 28.6kg/m2, CCI: 0.97). By approach, 21.9% underwent anterior only, 37.1% posterior only and 41% combined approaches. Average number of levels fused was 6.9, with a mean EBL of 948 ml and total operative time of 544.2 minutes. Mean EQ5D at BL was 0.74+/-0.07 and at 1Y was 0.79+/-0.08 (a difference of 0.05+/-0.08). Average difference in EQ5D from BL to 1Y was significant (p=0.002) across approach: 0.093 anterior-only, 0.021 posterior-only, 0.044 combined. 13% (3) of anterior-only patients underwent a revision, 10.3% (4) of posterior and 13.9% (6) of combined approaches. The average costs per surgery for CD patients at 1-year undergoing surgery by anterior approach was $27,640.75, $38,499.44 posterior-only, and $36,553.41 combined approach (p>0.05).The cost per QALY was higher for posterior-only patients at 1-year ($948,946.81) compared to anterior-only ($152,616.65) and combined ($424,110.14), p<0.001. If the utility gained was sustained to life expectancy, the cost per QALY for the anterior-only group was $21,665.87, posterior-only was $134,715.06 and combined approach was $60,207.82., p<0.001. After PSM for TS-CL, 15 patients remained in each group. The cost per QALY remained higher for posterior-only patients at 1-year and LE (both p<0.050).
CONCLUSION(S): After accounting for comorbidities, complications, revisions, and death, all surgical approaches showed improvement in postoperative EQ5D scores, however posterior approach demonstrated overall lower cost effectiveness. CD patients who underwent anterior-only approach had the lowest average costs for CD corrective surgery, as well as the lowest cost per QALY (best cost-effectiveness) compared to posterior and combined approaches. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Although researchers have extensively studied factors predicting clinical outcomes at static time points, assessing rate of recovery after adult spinal deformity (ASD) surgery has largely been ignored. This study aims to address this gap in knowledge by evaluating the impact of frailty and invasiveness on recovery kinetics, using area-under-the-curve (AUC) methodology. PURPOSE: To assess the impact of patient specific and surgical factors on postoperative recovery kinetics. STUDY DESIGN/SETTING: Retrospective review of a prospective, multicenter database. PATIENT SAMPLE: A total of 320 patients were identified from a multicenter database who had minimum 2-year HRQOL follow-up, with preoperative, 6-week and 1-year data available. OUTCOME MEASURES: Our primary outcome measure was integrated health state (IHS) score, a marker of postoperative recovery.
METHOD(S): ASD patients with minimum 2-year follow-up were stratified by frailty and surgical invasiveness. Previously validated ASD-FI scores were used to separate non-frail (<.3) patients from those that there were frail (.3 to.5) and severely frail (>.5). Patients were also stratified by surgical inverness, using ASD-SR, into four quartiles, Q1: <65, Q2: 66-89, Q3: 90-119, Q4: >120. Patient demographics, BMI, CCI and surgical parameters were also collected. To assess recovery kinetics, SRS-22r and ODI scores at 6-weeks, 1-year and 2-year were normalized against preoperative values and graphed as a function of time. AUC was summed across all time points to generate a single IHS score. Multivariate linear regression was used with IHS scores as primary outcome variable.
RESULT(S): A total of 320 patients met the inclusion and exclusion criteria. The mean (SD) patient age was 58.6 (14.7) with 79% female. Overall, 139 were non-frail, 131 frail and 46 severely frail. On univariate analysis, frail and severely frail patients were noted to have worse baseline and 2-year HRQOL scores for SRS pain, activity and ODI; however, when comparing differences in HRQOL across this 2-year period, F and SF were noted to have greater improvements in both SRS and ODI (p<.05). On multivariate regression, frail and severely frail patients, compared to those non-frail, were found to have better IHS scores for ODI, SRS-22r pain, and SRS-22r activity, indicating more favorable recovery (p<.05). In particular, for SRS-22r activity, frail (adjusted beta: 0.37, p=<.01) and severely frail (adjusted beta: 0.74, p=<.01) patients were found to have higher IHS compared to their non-frail counterparts. Similarly, for SRS-22r pain, frail and severely frail patients showed improved recovery with higher IHS scores in comparison to non-frail patients. In contrast to frailty, operative variables, including surgical invasiveness and EBL, were insignificant predictors of IHS scores for either ODI or SRS-22r domains.
CONCLUSION(S): Our results suggest that patient-specific factors, namely frailty, play a larger role in predicting postoperative recovery kinetics, in comparison to surgical factors, which appear to have limited if any impact. Despite frail patients having lower preoperative and 2-year HRQOL scores, they were noted to have higher IHS scores SRS pain, activity, and ODI indicating more favorable recovery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Prior literature has demonstrated that correction of sagittal plane deformity in adult patients has resulted in improvements in health-related quality of life (HRQOL) outcomes. In the absence of sagittal plane pathology, the effects of coronal malalignment under-correction in patients with spinal deformity have not been fully investigated. PURPOSE: To evaluate the impact of coronal malalignment correction on HRQOL outcomes in adult spinal deformity. STUDY DESIGN/SETTING: Retrospective review of a multicenter database. PATIENT SAMPLE: A total of 522 ASD patients had preoperative coronal malalignment greater than 40 mm. We excluded anyone who had SVA greater than 50 mm in order to control for patients without severe sagittal deformities. OUTCOME MEASURES: Our outcome measures included Oswestry Disability Index (ODI), SF-36 Physical Component Summary (PCS), and several other SF-36 and SRS-22r health domains scores.
METHOD(S): Using a prospective, multicenter database, we identified 1560 surgical patients. Of these, 522 patients had preoperative coronal malalignment greater than 40 mm. We excluded anyone who had SVA greater than 50 mm in order to control for patients who only had coronal plane deformity. We only included patients undergoing primary surgery. We then compared 2-year post HRQOL outcomes in patients that had their coronal malalignment corrected (CVA < 40mm) vs not.
RESULT(S): Mean age of patients was 54 +/- 15 years, 91% females. 79 patients were identified with only a coronal plane deformity undergoing a primary ASD surgery. Of these, 38 (48%) were under-corrected and 41 (52%) had their coronal alignment corrected to <40mm. Compared to the corrected group, the uncorrected group had a higher ODI (26.0+/- 2.9 vs 14.7+/- 2.5; p=0.002) and lower SRS-22r Activity (3.6+/- 0.14 vs 4.2+/- 0.11; p=002), SRS-22r Appearance (3.3+/- 0.16 vs 3.9+/- 0.12, p=.001), SRS-22r total (3.6+/- 0.12 vs 4.1+/- 0.11, p=.004), SF-36 Physical Component Summary (40.8+/- 1.3 vs 46.8+/- 1.6; p=.005), SF-36 Physical Function (40.5+/- 1.7 vs 46.0+/- 1.5, p=.01), SF-36 Bodily Pain (41.7+/- 1.6 vs 47.8+/- 1.5, p=.006), SF-36 General Health (47.2+/- 1.8 vs 52.2+/- 1.4, p=.03), SF-36 Social Functioning (45.9+/- 2.1 vs 51.7+/- 1.4, p=.03), SF-36 Mental Health (48.9+/- 1.9 vs 54.2+/- 1.8, p=.048) 2 years following index surgery.
CONCLUSION(S): Patients with coronal malalignment and little sagittal plane deformity experience worse improvement in pain and disability, with under-correction of their coronal plane deformity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Frailty is an increasingly recognized characteristic that has been validated across many studies as influencing operative risk. Utilization of frailty indices can allow for its identification of which spine patients may be too high risk for surgical intervention. This may be especially useful when it comes to surgeries that are minimally invasive and are supposed to have decrease perioperative outcomes. PURPOSE: Identify MIS techniques effects in postoperative outcomes in TLIF patients. STUDY DESIGN/SETTING: Retrospective review of a prospective database. PATIENT SAMPLE: TLIF spine patients. OUTCOME MEASURES: Complications, length of stay (LOS), estimated blood loss (EBL).
METHOD(S): Pts that underwent a lumbar spine procedure in a single-center Comprehensive Spine Quality Database. Pts were stratified based on procedural approach (Open [OP] and Minimally invasive Surgery [MIS]). Frailty was then calculated for each resultant group by using 30 variables with a validated method. Based on these scores, pts were categorized no frailty [NF]: <0.09, frail [F]: 0.09-0.18, and severe frailty [SF] >0.18. Groups were then controlled for surgical invasiveness. Chi-squared tests identified the relationship between complications and length of stay among various frailty states given surgical approach (OP vs MIS). These patients were propensity score matched for levels fused. Hospital acquired complications (HACs) were identified based on frailty groups through the use of chi-squared and t-tests for other surgical factors. A logistic regression analysis identified the association between frailty status and surgical, regarding postoperative (postop) outcomes.
RESULT(S): A total of 1,300 TLIF spine patients were isolated (59yrs, 29.3kg/m2). After PSM for levels fused, there were 338 pts for both MIS and OP. MIS pts were older (56.1 vs 53.3; p<0.05) than Op pts and had similar BMI's (29.1 vs 29.7; respectively). However, OP received more posterior approaches and less anterior approaches than MIS pts (p<0.05). By surgical factors: MIS and OP patients had similar LOS (3 vs 2.9days) and EBL (282.8 vs 251.5cc) but differed by Op time (195.7 vs 247.1; p<0.05) respectively. Further breakdown by frailty displayed statistical significance between MIS and OP patients with MIS pts having more F (16% vs 12%) and SF pts (4.3% vs 1.9%) than OP (all p<0.05). FMIS patients had lower postop neurologic complications as compared to FOP pts (4.63% vs 14.8%). However, SFMIS patiens had more post-operative complications than SFOP pts (55.2% vs 23.1%) and increased a pt's likelihood of being SFMIS by 5.4x's (all p<0.05).
CONCLUSION(S): This study displays that when frailty status is taken into account, TLIF MIS patients benefit from this procedure type when analyzed against neurologic complications. However, these patients were seen to suffer more from postop complications but did not differ on any other specific complications or surgical variables. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Age and pelvic incidence (PI) optimal alignment has been shown to minimize mechanical complications such as PJK. Low PI patients may be susceptible to overcorrection because PI specific alignment is not always prioritized. PURPOSE: The purpose of this study is to examine the incidence of over-correction in low PI ASD patients undergoing surgical intervention, and to quantify the impact of over-correction on radiographic PJK in this patient population. STUDY DESIGN/SETTING: Retrospective analysis of a prospective, multicenter database. PATIENT SAMPLE: Surgical ASD patients with low pelvic incidence. OUTCOME MEASURES: PJK defined as 1) proximal junctional angle (PJA, U

BACKGROUND CONTEXT: AI algorithms have shown substantial promise in medical image analysis. Previous studies of ASD clusters have analyzed alignment metrics - this study sought to complement these efforts by analyzing images of anatomical landmarks. PURPOSE: We hypothesized that a neural-network-based artificial intelligence (AI) algorithm would cluster preoperative lateral radiographs of into groups with distinct morphology. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: A total of 915 patients with adult spinal deformity and preoperative lateral radiographs. OUTCOME MEASURES: Schwab modifiers for SVA and PI-LL, three-column osteotomy, upper instrumented vertebrae, baseline Oswestry Disability Index, and 2-year likelihood of reaching MCID in ODI (set at -12.8). Proximal junctional kyphosis and proximal junctional failure were defined using previously published radiographic criteria.
METHOD(S): Vertebral locations for C3-L5, sacral endplate, and femoral heads were measured on lateral radiographs. Pixel locations were used to create a black-and-white overlay to the image, which was subsequently standardized for size and position using the femoral heads and sacral endplate. These images were used to train a self-organizing map (SOM). SOMs are a form of artificial neural network frequently employed in unsupervised classification tasks.
RESULT(S): In total, 915 preoperative lateral radiographs were analyzed. A 2 x 3, toroidal SOM was trained. The mean spine shape was plotted for each cluster. Alignment, surgical characteristics, and outcomes were compared between clusters. Clusters C and D exhibited a particularly high proportion of patients with optimal (ie, modifier 0) values of PI-LL (65.0% and 68.5%) and SVA (72.8% and 53.1%). Conversely, clusters B, E, and F tended to have poor (ie, modifier ++) PI-LL (74.8%, 66.9%, and 74.6%) and SVA (75.5%, 48.6%, and 58.7%). 3-CO was most common among cluster A (26.8%), cluster B (32.6%), and cluster F (32.7%). UIV at T7-T12 was most common among cluster B (51.1%) and cluster F (60.3%). ODI <30 was most prevalent among cluster D (31.4%). There was little difference, however, between groups in likelihood of reaching MCID in ODI at 2-year follow-up. PJK and PJF were particularly prevalent among clusters A (51.2% and 15.5%) and E (50.4% and 18.7%).
CONCLUSION(S): This study developed a self-organizing map that clustered preoperative lateral radiographs of ASD patients into groups with highly distinct overall spinal morphology. These clusters predicted alignment, surgical characteristics, and HRQOL. Further studies of this classification approach will expand to compare pre- and postoperative radiographs. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Thoracolumbar malalignment is often seen in patients presenting with cervical deformities. For operative cervical deformity (CD) patients, it is unknown whether certain thoracolumbar parameters play a large role in poor outcomes (complications, distal junctional kyphosis, reoperation) and whether addressment of such parameters is warranted. PURPOSE: To investigate the impact of cervical to thoracolumbar ratios on poor outcomes in CD corrective surgery. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: 110 CD patients. OUTCOME MEASURES: Radiographic parameters: regionally and globally; complications; distal junctional kyphosis (DJK); reoperations; health-related quality-of-life (HRQLs): NDI, EQ5D, mJOA.
METHOD(S): Included: surgical CD pts (C2-C7 Cobb >10degree, CL>10degree, cSVA >4cm, or CBVA >25degree) with full baseline and 1-year data. Patients were assessed for ratios of preop cervical and global parameters including: C2 slope/T1 slope, TS-CL/PI-LL, cSVA/SVA. Deformity classification ratios of cervical (Ames-ISSG) to spinopelvic (SRS-Schwab) were investigated: cSVA modifier/SVA modifier, TS-CL modifier/PI-LL modifier. Cervical to thoracic ratios included C2-C7 lordosis/T4-T12 kyphosis. Correlations assessed the relationship between ratios and poor outcome (major complication, reoperation, HRQL decline or failure to meet MCID). Decision tree analysis through multiple iterations of multivariate regressions assessed cut-offs for ratios for acquiring suboptimal outcomes.
RESULT(S): A total of 110 cervical deformity patients were included in the present analysis (61.5+/-9.9 years, 66% female, 28.8+/-7.5 kg/m2). By approach, 18.2% underwent anterior-only procedures, 46.4% posterior, and 35.4% combined. Average levels fused: 7.7+/-3.7 levels (anterior: 3.5, posterior: 8.5). The average preoperative radiographic ratios assessed included a C2 slope/T1 slope 1.56, TS-CL/PI-LL of 11.1, cSVA/SVA of 5.4, CL/TK of 0.26. Ames-ISSG and SRS-Schwab modifier ratios of cSVA/SVA 0.1 and TS-CL/PI-LL of 0.35. Pearson correlations demonstrated a significant relationship between major complications and the baseline TS-CL/PI-LL with a cutoff of >12.72 (p=0.034), >0.482 Ames TS-CL/Schwab PI-LL modifiers (p=0.019), and the CL/TK ratios (>0.814, p=0.050). Reoperation had a significant correlation with the TS-CL/PI-LL (>5.819, p=0.009) and the cSVA/SVA (>3.79, p=0.002) ratios. Postoperative DJK had a correlation with the C2 slope/T1 slope (>1.59, p=0.017) and CL/TK (>0.692, p=0.0629) ratios. Not meeting MCID for NDI correlated with the CL/TK ratio (>1.402, p=0.016) and not meeting MCID for EQ5D correlated with the Ames TS-CL/Schwab PI-LL (>0.564, p=0.010).
CONCLUSION(S): Consideration of the ratio of distal regional to global alignment is a critical determinant of outcomes in cervical deformity corrective surgery. Several key ratios of cervical to global alignment were found to correlate with the occurrence of suboptimal realignment parameters, or poor clinical outcomes. A larger cervical lordosis to thoracic kyphosis was most representative of this risk, which predicted a complication, DJK, and not meeting MCID for NDI. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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