Browsing by Author "Mundis, GM"

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Open Access
A comparative cohort study of surgical approaches for adult spinal deformity at a minimum 2-year follow-up
(European Spine Journal, 2024-01-01) Kazarian, GS; Feuchtbaum, E; Bao, H; Soroceanu, A; Kelly, MP; Kebaish, KM; Shaffrey, CI; Burton, DC; Ames, CP; Mundis, GM; Bess, S; Klineberg, EO; Swamy, G; Schwab, FJ; Kim, HJ
Study design: This study was a retrospective multi-center comparative cohort study. Materials and methods: A retrospective institutional database of operative adult spinal deformity patients was utilized. All fusions > 5 vertebral levels and including the sacrum/pelvis were eligible for inclusion. Revisions, 3 column osteotomies, and patients with < 2-year clinical follow-up were excluded. Patients were separated into 3 groups based on surgical approach: 1) posterior spinal fusion without interbody (PSF), 2) PSF with interbody (PSF-IB), and 3) anteroposterior (AP) fusion (anterior lumbar interbody fusion or lateral lumbar interbody fusion with posterior screw fixation). Intraoperative, radiographic, and clinical outcomes, as well as complications, were compared between groups with ANOVA and χ2 tests. Results: One-hundred and thirty-eight patients were included for study (PSF, n = 37; PSF-IB, n = 44; AP, n = 57). Intraoperatively, estimated blood loss was similar between groups (p = 0.171). However, the AP group had longer operative times (547.5 min) compared to PSF (385.1) and PSF-IB (370.7) (p < 0.001). Additionally, fusion length was shorter in PSF-IB (11.4) compared to AP (13.6) and PSF (12.9) (p = 0.004). There were no differences between the groups in terms of change in alignment from preoperative to 2 years postoperative. There were no differences in clinical outcomes. While postoperative complications were largely similar between groups, operative complications were higher in the AP group (31.6%) compared to the PSF (5.4%) and PSF-IB (9.1) groups (p < 0.001). Conclusion: While there were differences in intraoperative outcomes (operative time and fusion length), there were no differences in postoperative clinical or radiographic outcomes. AP fusion was associated with a higher rate of operative complications.
Open Access
Clinically Significant Thromboembolic Disease in Adult Spinal Deformity Surgery: Incidence and Risk Factors in 737 Patients
(Global Spine Journal, 2018-05-01) Kim, HJ; Iyer, S; Diebo, BG; Kelly, MP; Sciubba, D; Schwab, F; Lafage, V; Mundis, GM; Shaffrey, CI; Smith, JS; Hart, R; Burton, D; Bess, S; Klineberg, EO
Study Design: Retrospective cohort study. Objectives: Describe the rate and risk factors for venous thromboembolic events (VTEs; defined as deep venous thrombosis [DVT] and/or pulmonary embolism [PE]) in adult spinal deformity (ASD) surgery. Methods: ASD patients with VTE were identified in a prospective, multicenter database. Complications, revision, and mortality rate were examined. Patient demographics, operative details, and radiographic and clinical outcomes were compared with a non-VTE group. Multivariate binary regression model was used to identify predictors of VTE. Results: A total of 737 patients were identified, 32 (4.3%) had VTE (DVT = 14; PE = 18). At baseline, VTE patients were less likely to be employed in jobs requiring physical labor (59.4% vs 79.7%, P <.01) and more likely to have osteoporosis (29% vs 15.1%, P =.037) and liver disease (6.5% vs 1.4%, P =.027). Patients with VTE had a larger preoperative sagittal vertical axis (SVA; 93 mm vs 55 mm, P <.01) and underwent larger SVA corrections. VTE was associated with a combined anterior/posterior approach (45% vs 25%, P =.028). VTE patients had a longer hospital stay (10 vs 7 days, P <.05) and higher mortality rate (6.3% vs 0.7%, P <.01). Multivariate analysis demonstrated osteoporosis, lack of physical labor, and increased SVA correction were independent predictors of VTE (r2 =.11, area under the curve = 0.74, P <.05). Conclusions: The incidence of VTE in ASD is 4.3% with a DVT rate of 1.9% and PE rate of 2.4%. Osteoporosis, lack of physical labor, and increased SVA correction were independent predictors of VTE. Patients with VTE had a higher mortality rate compared with non-VTE patients.
Open Access
Evolving concepts in pelvic fixation in adult spinal deformity surgery
(Seminars in Spine Surgery, 2023-01-01) Turner, JD; Schupper, AJ; Mummaneni, PV; Uribe, JS; Eastlack, RK; Mundis, GM; Passias, PG; DiDomenico, JD; Harrison Farber, S; Soliman, MAR; Shaffrey, CI; Klineberg, EO; Daniels, AH; Buell, TJ; Burton, DC; Gum, JL; Lenke, LG; Bess, S; Mullin, JP
Long-segment adult spinal deformity (ASD) constructs carry a high risk of mechanical complications. Pelvic fixation was introduced to improve distal construct mechanics and has since become the standard for long constructs spanning the lumbosacral junction. Pelvic fixation strategies have evolved substantially over the years. Numerous techniques now use a variety of entry points, screw trajectories, and construct configurations. We review the various strategies for pelvic fixation in ASD in a systematic review of the literature and update the techniques employed in the International Spine Study Group Complex Adult Deformity Surgery database.
Open Access
Impact of obesity on complications, infection, and patient-reported outcomes in adult spinal deformity surgery
(Journal of Neurosurgery: Spine, 2015-11-01) Soroceanu, A; Burton, DC; Diebo, BG; Smith, JS; Hostin, R; Shaffrey, CI; Boachie-Adjei, O; Mundis, GM; Ames, C; Errico, TJ; Bess, S; Gupta, MC; Hart, RA; Schwab, FJ; Lafage, V
OBJECT: Adult spinal deformity (ASD) surgery is known for its high complication rate. This study examined the impact of obesity on complication rates, infection, and patient-reported outcomes in patients undergoing surgery for ASD. METHODS: This study was a retrospective review of a multicenter prospective database of patients with ASD who were treated surgically. Patients with available 2-year follow-up data were included. Obesity was defined as having a body mass index (BMI) ≥ 30 kg/m2. Data collected included complications (total, minor, major, implant-related, radiographic, infection, revision surgery, and neurological injury), estimated blood loss (EBL), operating room (OR) time, length of stay (LOS), and patient-reported questionnaires (Oswestry Disability Index [ODI], Short Form-36 [SF-36], and Scoliosis Research Society [SRS]) at baseline and at 6 weeks, 1 year, and 2 years postoperatively. The impact of obesity was studied using multivariate modeling, accounting for confounders. RESULTS: Of 241 patients who satisfied inclusion criteria, 175 patients were nonobese and 66 were obese. Regression models showed that obese patients had a higher overall incidence of major complications (IRR 1.54, p = 0.02) and wound infections (odds ratio 4.88, p = 0.02). Obesity did not increase the number of minor complications (p = 0.62), radiographic complications (p = 0.62), neurological complications (p = 0.861), or need for revision surgery (p = 0.846). Obesity was not significantly correlated with OR time (p = 0.23), LOS (p = 0.9), or EBL (p = 0.98). Both groups experienced significant improvement over time, as measured on the ODI (p = 0.0001), SF-36 (p = 0.0001), and SRS (p = 0.0001) questionnaires. However, the overall magnitude of improvement was less for obese patients (ODI, p = 0.0035; SF-36, p = 0.0012; SRS, p = 0.022). Obese patients also had a lower rate of improvement over time (SRS, p = 0.0085; ODI, p = 0.0001; SF-36, p = 0.0001). CONCLUSIONS: This study revealed that obese patients have an increased risk of complications following ASD correction. Despite these increased complications, obese patients do benefit from surgical intervention; however, their improvement in health-related quality of life (HRQL) is less than that of nonobese patients.
Open Access
Lowest Instrumented Vertebra Selection to S1 or Ilium Versus L4 or L5 in Adult Spinal Deformity: Factors for Consideration in 349 Patients With a Mean 46-Month Follow-Up
(Global Spine Journal, 2023-05-01) Yao, YC; Kim, HJ; Bannwarth, M; Smith, J; Bess, S; Klineberg, E; Ames, CP; Shaffrey, CI; Burton, D; Gupta, M; Mundis, GM; Hostin, R; Schwab, F; Lafage, V
Study Design: Retrospective cohort study. Objective: To compare the outcomes of patients with adult spinal deformity (ASD) following spinal fusion with the lowest instrumented vertebra (LIV) at L4/L5 versus S1/ilium. Methods: A multicenter ASD database was evaluated. Patients were categorized into 2 groups based on LIV levels—groups L (fusion to L4/L5) and S (fusion to S1/ilium). Both groups were propensity matched by age and preoperative radiographic alignments. Patient demographics, operative details, radiographic parameters, revision rates, and health-related quality of life (HRQOL) scores were compared. Results: Overall, 349 patients had complete data, with a mean follow-up of 46 months. Patients in group S (n = 311) were older and had larger sagittal and coronal plane deformities than those in group L (n = 38). After matching, 28 patients were allocated to each group with similar demographic, radiographic, and clinical parameters. Sagittal alignment restoration at postoperative week 6 was significantly better in group S than in group L, but it was similar in both groups at the 2-year follow-up. Fusion to S1/ilium involved a longer operating time, higher PJK rates, and greater PJK angles than that to L4/L5. There were no significant differences in the complication and revision rates between the groups. Both groups showed significant improvements in HRQOL scores. Conclusions: Fusion to S1/ilium had better sagittal alignment restoration at postoperative week 6 and involved higher PJK rates and greater PJK angles than that to L4/L5. The clinical outcomes and rates of revision surgery and complications were similar between the groups.
Open Access
Quantifying the importance of upper cervical extension reserve in adult cervical deformity surgery and its impact on baseline presentation and outcomes
(Spine Journal, 2024-09-01) Passias, PG; Mir, J; Smith, JS; Lafage, V; Lafage, R; Diebo, BG; Daniels, AH; Onafowokan, O; Line, B; Eastlack, RK; Mundis, GM; Kebaish, KM; Soroceanu, A; Scheer, JK; Kelly, MP; Protopsaltis, TS; Kim, HJ; Hostin, RA; Gupta, MC; Riew, KD; Burton, DC; Schwab, FJ; Bess, S; Shaffrey, CI; Ames, CP
BACKGROUND CONTEXT: Hyperextension of the upper cervical spine is a prominent compensatory mechanism to maintain horizontal gaze and balance in adult cervical deformity (ACD) patients, akin to pelvic tilt in spinal deformity. The relaxation of ER and its impact on postoperative outcomes is not well understood. PURPOSE: To evaluate upper cervical ER impact on postoperative disability and outcomes. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: Adult cervical deformity. OUTCOME MEASURES: ER, HRQLs. METHODS: ACD patients undergoing subaxial cervical fusion with 2Y data were included. Upper cervical extension reserve (ER) was defined as: C0-C2 sagittal Cobb angle between neutral and extension. Relaxation of ER was defined as the ER normative mean in those that met the ideal in all Passias ACD modifiers. Outcomes were defined as "good" if meeting ≥2 of the three: (1) NDI <20 or meeting MCID, (2) mild myelopathy (mJOA≥14), and (3) NRS-Neck ≤5 or improved by ≥2 points from baseline. Controlled analysis was conducted with ANCOVA and multivariable logistic regressions. Conditional inference tree (CIT) analysis determined thresholds. RESULTS: A total of 108 ACD patients met inclusion. (Age 61.4 ± 12.3, 61% F, BMI 29.4 ± 7.5 kg/m2, mCD-FI .24 ±.12, CCI 0.97 ± 1.30). Radiographic alignment is depicted in Table 1. Preoperative C0-C2 ER was 8.7 ±9.0 ±, and at the last follow-up was 10.3 ± 11.1. ER in those meeting all ideal CD modifiers at 2Y was 12.9 ± 9.0. Preoperatively 29% had adequate ER, while 59.7% had improvement in ER postoperatively, with 50% of patients achieving adequate ER at 2Y. Higher ER significantly correlated with lower cervical deformity (p<.05). Preoperatively, greater ER was predictive of lower preoperative disability, with worse baseline mobility, pain, and anxiety (EQ5D) (B = -6.1, -2.9, -2.9 respectively; R2 =0.212, p<.001). Improvement of ER depicted a higher rate of MCID for NDI (64% vs 39%, p=.008), and meeting good clinical outcomes (72% vs 54%, p=.04). Controlling for baseline deformity and demographic factors found resolution of inadequate ER to have 7x higher likelihood of meeting MCID for NDI (6.941 [1.378-34.961], p=.019) and 4x higher odds of achieving good outcomes (4.022 [1.017-15.900], p=.047). Isolating those with inadequate preoperative ER, found postoperative resolution having 5x odds of good outcomes (p<.05). In those with inadequate ER at baseline, the preoperative C2-C7 of <-18 and TS-CL of >59 for TS-CL was predictive of ER resolution (p<.05). In those with preoperative C2-C7 >-18, a T1PA of >13 was predictive of postoperative return of ER (p<.05). Independently TS-CL of >59, was significant for predicting ER return postoperatively, highlighting its compensatory role for proximal spinal deformities (all p<.05). Surgical correction of C2-C7 by >16 from baseline was found to be predictive of ER return. CONCLUSIONS: Increased preoperative utilization of the extension reserve in the upper cervical spine in cervical deformity was associated with worse baseline regional and global alignment while impacting health-related measures. The majority of patients had relaxation of extension reserve postoperatively, however, in those who didn't, there was a decreased likelihood of achieving good outcomes. FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.
Open Access
Radiographic outcomes of adult spinal deformity correction: A critical analysis of variability and failures across deformity patterns
(Spine Deformity, 2014-01-01) Moal, B; Schwab, F; Ames, CP; Smith, JS; Ryan, D; Mummaneni, PV; Mundis, GM; Terran, JS; Klineberg, E; Hart, RA; Boachie-Adjei, O; Shaffrey, CI; Skalli, W; Lafage, V
Study Design Multicenter, prospective, consecutive, surgical case series from the International Spine Study Group. Objectives To evaluate the effectiveness of surgical treatment in restoring spinopelvic (SP) alignment. Summary of Background Data Pain and disability in the setting of adult spinal deformity have been correlated with global coronal alignment (GCA), sagittal vertical axis (SVA), pelvic incidence/lumbar lordosis mismatch (PI-LL), and pelvic tilt (PT). One of the main goals of surgery for adult spinal deformity is to correct these parameters to restore harmonious SP alignment. Methods Inclusion criteria were operative patients (age greater than 18 years) with baseline (BL) and 1-year full-length X-rays. Thoracic and thoracolumbar Cobb angle and previous mentioned parameters were calculated. Each parameter at BL and 1 year was categorized as either pathological or normal. Pathologic limits were: Cobb greater than 30°, GCA greater than 40 mm, SVA greater than 40 mm, PI-LL greater than 10°, and PT greater than 20°. According to thresholds, corrected or worsened alignment groups of patients were identified and overall radiographic effectiveness of procedure was evaluated by combining the results from the coronal and sagittal planes. Results A total of 161 patients (age, 55 ± 15 years) were included. At BL, 80% of patients had a Cobb angle greater than 30°, 25% had a GCA greater than 40 mm, and 42% to 58% had a pathological sagittal parameter of PI-LL, SVA, and/or PT. Sagittal deformity was corrected in about 50% of cases for patients with pathological SVA or PI-LL, whereas PT was most commonly worsened (24%) and least often corrected (24%). Only 23% of patients experienced complete radiographic correction of the deformity. Conclusions The frequency of inadequate SP correction was high. Pelvic tilt was the parameter least likely to be well corrected. The high rate of SP alignment failure emphasizes the need for better preoperative planning and intraoperative imaging. © 2014 Scoliosis Research Society.
Open Access
Redefining Clinically Significant Blood Loss in Complex Adult Spine Deformity Surgery
(Spine, 2024-01-01) Daher, M; Xu, A; Singh, M; Lafage, R; Line, BG; Lenke, LG; Ames, CP; Burton, DC; Lewis, SM; Eastlack, RK; Gupta, MC; Mundis, GM; Gum, JL; Hamilton, KD; Hostin, R; Lafage, V; Passias, PG; Protopsaltis, TS; Kebaish, KM; Schwab, FJ; Shaffrey, CI; Smith, JS; Bess, S; Klineberg, EO; Diebo, BG; Daniels, AH
Study Design. Retrospective analysis of prospectively-collected data Objective. This study aims to define clinically relevant blood loss in adult spinal deformity (ASD) surgery. Background. Current definitions of excessive blood loss following spine surgery are highly variable and may be suboptimal in predicting adverse events (AE). Methods. Adults undergoing complex ASD surgery were included. Estimated blood loss (EBL) was extracted for investigation, and estimated blood volume loss (EBVL) was calculated by dividing EBL by the preoperative blood volume utilizing Nadler's formula. LASSO regression was performed to identify five variables from demographic and peri-operative parameters. Logistic regression was subsequently performed to generate a receiver operating characteristics (ROC) curve and estimate an optimal threshold for EBL and EBVL. Finally, the proportion of patients with AE plotted against EBL and EBVL to confirm the identified thresholds. Results. In total 552 patients were included with a mean age of 60.7±15.1 years, 68% females, mean CCI was 1.0±1.6, and 22% experienced AEs. LASSO regression identified ASA score, baseline hypertension, preoperative albumin, and use of intra-operative crystalloids as the top predictors of an AE, in addition to EBL/EBVL. Logistic regression resulted in ROC curve which was used to identify a cut-off of 2.3 liters of EBL and 42% for EBVL. Patients exceeding these thresholds had AE rates of 36% (odds-ratio: 2.1, 95% CI [1.2-3.6]) and 31% (odds-ratio: 1.7, 95% CI [1.1-2.8]), compared to 21% for those below the thresholds of EBL and EBVL, respectively. Conclusion. In complex ASD surgery, intraoperative EBL of 2.3 liters and an EBVL of 42% are associated with clinically-significant AEs. These thresholds may be useful in guiding preoperative-patient-counseling, healthcare system quality initiatives, and clinical perioperative bloodloss management strategies in patients undergoing complex spine surgery. Additionally, similar methodology could be performed in other specialties to establish procedure-specific clinically-relevant bloodloss thresholds.
Open Access
“Selection, planning and execution of minimally invasive surgery in adult spinal deformity correction”
(Seminars in Spine Surgery, 2023-01-01) Alan, N; Uribe, JS; Turner, JD; Park, P; Anand, N; Eastlack, RK; Okonkwo, DO; Le, VP; Nunley, P; Mundis, GM; Passias, PG; Chou, D; Kanter, AS; Fu, KMG; Wang, MY; Fessler, RG; Shaffrey, CI; Bess, S; Mummaneni, PV
Minimally invasive surgery (MIS) for correction of adult spinal deformity was developed to address the high rate of medical and surgical complications rate in open surgical treatment of increasingly aging and frail patient population. In the past decade, MIS group within the International Spine Study Group (ISSG) has been in the forefront of the application of MIS techniques to fulfill the well-established principles of ASD surgery. These efforts have resulted in landmark studies. Here, we review these studies that encompass all aspects of MIS surgical treatment of ASD including patient selection with Minimally Invasive Spinal Deformity Surgery (MISDEF) and MISDEF-2 algorithms, surgical planning with anterior column realignment classification and the Minimally Invasive Interbody Selection Algorithm (MIISA), and surgical execution with Spinal Deformity Complexity Checklist (SDCC). We will highlight that with careful selection, diligent planning and meticulous execution the MIS techniques can treat patients with ASD, abiding to correction principles and radiographic parameters.
Open Access
Severe hip and knee osteoarthritis worsens patient-reported disability in adult spinal deformity patients
(Spine Journal, 2024-09-01) Balmaceno-Criss, M; Singh, M; Xu, A; Daher, M; Lafage, R; Lewis, SJ; Klineberg, EO; Eastlack, RK; Gupta, MC; Mundis, GM; Gum, JL; Hamilton, DK; Hostin, RA; Passias, PG; Protopsaltis, TS; Kebaish, KM; Kim, HJ; Shaffrey, CI; Smith, JS; Line, B; Lenke, LG; Ames, CP; Burton, DC; Bess, S; Schwab, FJ; Lafage, V; Diebo, BG; Daniels, AH
BACKGROUND CONTEXT: The complex interplay between lower extremity osteoarthritis and sagittal alignment in adult spinal deformity patients is of growing clinical interest. PURPOSE: To quantify the sequential effects of lower extremity OA on PROMs in ASD patients. STUDY DESIGN/SETTING: Retrospective review of prospectively collected data. PATIENT SAMPLE: ASD patients with no prior history of thoracolumbar surgery, and available baseline PROMs and standing radiographs were included. OUTCOME MEASURES: Baseline demographics, spinopelvic alignment, and PROMs. METHODS: Included patients with PROMs, standing xrays, no prior thoracolumbar surgery, and bilateral Kellgren-Lawrence (KL) hip/knee grade at baseline. Patients grouped into Spine (KL <3 BL hips & knees), Spine-Hip (KL>3 BL hips, KL <3 BL knees), Spine-Knee (KL>3 BL knees, KL>3 BL hips), Spine-Hip-Knee (KL>3 BL hips & knees). Baseline demographics, spinopelvic alignment, and PROMs were compared. Multivariate regression with forward stepwise selection predicted PROMs with variables (demographic, radiographic, OA severity) with significant association identified on Pearson correlation RESULTS: Included 160 patients: 56 Spine, 32 Spine-Knee, 20 Spine-Hip, and 52 Spine-Hip-Knee. Spine-Hip-Knee patients were older (Spine=62.2, Spine-Knee=61.2, Spine-Hip=59.1, Spine-Hip-Knee=68.5; p<.001) but similar in sex, comorbidities, and frailty; p>.05. Spine-Hip-Knee patients had higher SVA (50.0,30.6,60.5,83.5), T1PA (25.2,20.4,20.3,27.8), GSA (3.7,2.3,4.3,7.5), and KA (0.0,2.1,2.9,10.5); p<.005. SRS total and VR12 PCS scores were similar but VR12-2b climbing stairs (1.73,1.91,1.55,1.40, p=.014) and SRS-8 back pain at rest (2.29,2.84,1.95,2.71, p=.012) were lower in Spine-Hip-Knee and Spine-Hip, respectively. ODI (42.75,35.88,50.30,44.59, p=.040) and ODI Pain (2.88,1.84,2.90,2.46, p=0.019) were higher in Spine-Hip patients; ODI lifting was higher in hip OA patients but not significant (2.95,2.69,3.45,3.35, p>.05). In multivariate analyses, KOA changed the prediction of ODI pain from R2 0.052 to 0.086 and SRS-8 from R2 0.077 to 0.147. HOA changed the prediction of VR12-2b from R2 0.113 to 0.140 and ODI Lifting from R2 0.175 to 0.202. Frailty impacted PROMs across all models (p<.001) and GSA changed ODI, ODI pain, and VR12-2b models (p<.05). CONCLUSIONS: Severe hip and knee OA worsen patient-reported disability and physical function in ASD patients. These results quantify the impact of lower limb arthritis on patient reported outcomes, and highlight the need for integrated assessment and management of both spinal alignment and joint health in patients. FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.
Open Access
The cervical lordosis distribution index and its consideration of upper cervical region and morphology
(Spine Journal, 2024-09-01) Williamson, TK; Passias, PG; Smith, JS; Lafage, R; Line, B; Diebo, BG; Daniels, AH; Gum, JL; Protopsaltis, TS; Hamilton, DK; Soroceanu, A; Eastlack, RK; Mundis, GM; Bess, S; Schwab, FJ; Shaffrey, CI; Lafage, V; Burton, DC
BACKGROUND CONTEXT: The cervical lordosis distribution in relation to its apex has not been characterized, nor has the impact of morphologic differences and upper cervical segments. PURPOSE: The goal of this study is assess whether tailored correction of cervical deformity by incorporating the cervical apex into a distribution index (CLDI) improves clinical outcomes while lowering rates of junctional failure. STUDY DESIGN/SETTING: Retrospective review of a prospectively-collected cohort; Multiple academic centers. PATIENT SAMPLE: A total of 84 patients met radiographic criteria for adult cervical deformity and at least 2-year follow-up. OUTCOME MEASURES: Optimal outcome is defined as meeting Virk et al Good Clinical Outcome (GCO): [Meeting 2 of 3: 1) NDI<20 or meeting MCID, 2) mJOA>=14, 3) NRS-Neck<=5 or improved by >2 points] and no occurrence of distal junctional failure (DJF). METHODS: C2-T2 lordosis was divided into cranial (C2-to-apex) and caudal (apex-to-T2) arches. A cervical lordosis distribution index (CLDI) was developed by dividing the cranial lordotic arch (C2 to apex) by the total segment (C2-T2) and multiplying by 100. Cross-tabulations developed categories for CLDI producing the highest chi-square values for achieving Optimal Outcome at two years and outcomes were assessed by multivariable analysis controlling for significant confounders. Patients stratified by Ames et al deformity classification then assessed against thresholds. Patients were further divided into those meeting thresholds with upper cervical compensation (defined by C0-C2 angle, C0 slope, McGregor's Slope [MGS]) vs without compensation. Multivariate regression analysis controlling for T1 slope assessed differences in classification and impact of upper cervical region. RESULTS: Cervical apex distribution postoperatively was: 1% C3, 42% C4, 30% C5, 27% C6. Mean cervical LDI was 117±138. Mean cranial lordosis was 23.2±12.5°. Using cross-tabulations, CLDI between 70 and 90 was defined as ‘Aligned’. Chi-square test revealed significant differences among CLDI categories for DJK, DJF, Good Clinical Outcome, and Optimal Outcome (all p<.05). Patients aligned in CLDI were less likely to develop DJK (OR: 0.1, [<0.1-0.9]), more like to achieve GCO (OR: 3.9, [1.2-13.2]) and Optimal Outcome (OR: 7.9, [2.1-29.3]) at two years. Patients aligned in CLDI developed DJF at a rate of 0%. Those meeting this CLDI threshold were more likely to be classified into primarily cervical deformity by Ames criteria (OR: 1.9, [3.2-10.6], p<.05). CONCLUSIONS: The cervical lordosis distribution index, classified through the cranial segment, takes each unique cervical apex into account and tailors correction to the patient in order to better achieve good clinical outcomes. While differences based on morphology exists, upper cervical region functions as a reserve in all deformity types. Consideration of regional and global factors allows for a comprehensive assessment and individualization of realignment surgery. FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.
Open Access
Who are super-utilizers in adult spine deformity surgery and how can surgeons identify them preoperatively?
(Spine Journal, 2024-09-01) Nayak, P; Hostin, RA; Staub, BN; Gum, JL; Line, B; Bess, S; Lenke, LG; Lafage, R; Smith, JS; Mullin, JP; Kelly, MP; Diebo, BG; Buell, TJ; Scheer, JK; Lafage, V; Klineberg, EO; Kim, HJ; Passias, PG; Kebaish, KM; Eastlack, RK; Daniels, AH; Soroceanu, A; Mundis, GM; Protopsaltis, TS; Hamilton, DK; Gupta, MC; Schwab, FJ; Shaffrey, CI; Ames, CP; Burton, DC
BACKGROUND CONTEXT: A relatively small percentage of patients are responsible for a disproportional amount of resource utilization in adult ASD surgery and contribute to significantly elevating the average cost across the surgically treated patients. These patients are called super-utilizers (SU). Modest reduction in the frequency of these super-utilization episodes has the potential to significantly improve the value of ASD surgery. PURPOSE: The goal of this study was to determine which, if any, baseline patient, radiographic, and/or surgical factors are the most important drivers of this disproportional increased resource utilization. We hypothesize that baseline patient factors predicts super-utilizers (SU) in adult spinal deformity surgery (ASD) more than surgical or deformity factors. STUDY DESIGN/SETTING: Retrospective Review of a prospective, multicenter registry. PATIENT SAMPLE: A total of 1299 index operative ASD patients eligible for 2-yr follow-up. OUTCOME MEASURES: Predictors of SU vs Non-SU in ASD. METHODS: A prospective multicenter consecutive series of ASD patients was reviewed. Inclusion criteria was diagnosis of ASD (scoliosis≥20°, C7-SVA≥5cm, PT≥25°, or TK≥60°), >4 level posterior fusion, and minimum 2-year follow-up. Index and total episode of care (EOC) cost in 2022 dollars were calculated using average itemized direct costs obtained from the administrative hospital records for all events in the inpatient EOC. Patients with total 2-year EOC cost greater than 90th percentile were considered SU. Multivariate generalized linear models were used to identify the most significant predictors of SU. RESULTS: A total of 1299 patients were eligible for 2-yr follow-up with mean age 60.0+14.1 years, 76% female, and 93% caucasians. SU patients are marginally older (+2.6 yrs; p=0.03), depressed (34.2% vs 25.8%; p=0.03) and tend to have higher propensity for fraility (p=0.003), comorbidities (0.01), reoperation rates (54.8% vs 17.0%; p<0.001), and LOS (+3 days; p<0.0001) compared to non-SU. While degree of sagittal deformity (Schwab sagittal modifiers, all p>0.05) and proportion of 3-column osteotomies (p>0.05) were similar between the groups, SU patients have higher surgical invasiveness score (+28; p<0.001), more vertebrae fused (+3; p<0.0001); more interbody fusions (80% vs 55%; p<0.0001), more BMP use (87.3% vs 69.4%; p=0.0002); longer OR time (+91 mins; p<0.0001), increased blood loss (+700 mL; p<0.0001), and longer length of stay (+3 days; p<0.0001). Index and EOC cost were 49% (p<0.0001) and 62% (p<0.0001) higher respectively in SU. While cost/QALY was 3-times higher in SU compared to non-SU. Multivariate analysis identified Schwab modifier SVA, surgical invasiveness, OR time, blood loss, BMP use, and LOS as strong predictors of SU (all p<0.01). CONCLUSIONS: Surgical invasiveness score greater than 118, being in OR for more than 7.6 hrs, blood loss more than 700 ml, utilizing BMP, and LOS more than 11 days were strong predictors of being a SU. Patients with SVA grade of + and ++ were less likely to be a SU compared to SVA grade 0. Procedural and resource utilization factors were strong predictors of being a SU compared to patient factors. FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.