Faculty Bibliography

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

BACKGROUND CONTEXT: Obesity's impact on standing sagittal alignment remains poorly understood, especially with respect to the role of the lower-limbs. Given energetic expenditure in standing, a complete understanding of compensation in obese patients with sagittal malalignment remains relevant. PURPOSE: This study compares obese and non-obese patients with progressive sagittal malalignment for differences in recruitment of pelvic and lower limb mechanisms. STUDY DESIGN/SETTING: Single center retrospective review. PATIENT SAMPLE: 554 patients (277 obese, 277 non-obese) identified for analysis. OUTCOME MEASURES: Upper body alignment parameters: sagittal vertical axis (SVA) and T1 spino-pelvic inclination (T1SPi). Compensatory lower-limb mechanisms: pelvic translation (PS: pelvic shift), knee (KA) and ankle (AA) flexion, hip extension (SFA: sacrofemoral angle), and global sagittal angle (GSA). METHODS: Inclusion criteria were patients>/=18 years that underwent full body stereographic x-rays. Included patients were categorized as non-obese (N-Ob: BMI<30 kg/m2) and obese (Ob: BMI>/=30 kg/m2). To control for potential confounders, groups were propensity score matched by age, gender and baseline pelvic incidence (PI), and subsequently categorized by increasing spino-pelvic (PI-LL) mismatch: <10 degrees , 10 degrees -20 degrees , >20 degrees . Independent t-tests and linear regression models compared sagittal (SVA, T1SPi) and lower limb (PS, KA, AA, SFA, GSA) parameters between obesity cohorts. RESULTS: 554 patients (277 Ob, 277 N-Ob) were included for analysis, and were stratified to the following mismatch categories: <10 degrees : n=367; 10 degrees -20 degrees : n=91; >20 degrees : n=96. Ob patients had higher SVA, KA, PS and GSA compared to N-Ob (p<0.001 all). Low PI-LL mismatch Ob patients had greater SVA with lower SFA (142.22 degrees vs. 156.66 degrees , p=0.032), higher KA (5.22 degrees vs. 2.93 degrees , p=0.004) and PS (4.91 vs. -5.20 mm, p<0.001) compared to N-Ob. With moderate PI-LL mismatch, Ob patients similarly demonstrated greater SVA, KA, and PS, combined with significantly lower PT (23.69 degrees vs. 27.14 degrees , p=0.012). Obese patients of highest (>20 degrees ) PI-LL mismatch showed greatest forward malalignment (SVA, T1SPi) with significantly greater PS, and a concomitantly high GSA (12.86 degrees vs. 9.67 degrees , p=0.005). Regression analysis for lower-limb compensation revealed that increasing BMI and PI-LL predicted KA (r2=0.234) and GSA (r2=0.563). CONCLUSIONS: With progressive sagittal malalignment, obese patients differentially recruit lower extremity compensatory mechanisms while non-obese preferentially recruit pelvic mechanisms. The ability to compensate for progressive sagittal malalignment with the pelvic retroversion is limited by obesity.

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction in patients older than age 55, with operative management being a widely adopted approach. Previous work has shown that private insurance status, gender and patient race are predictive of the operative approach patients receive (anterior-only, posterior-only, combined anterior-posterior). The Nationwide Inpatient Sample from 2001 to 2010 was used to assess the potential role of multilevel CSM as a contributing factor in determining which operative approach CSM patients receive, as it is rare for an anterior-only approach to be sufficient for CSM patients requiring fusion of four or more involved levels. Multivariate analyses revealed that female sex (OR=3.78; 95% CI=2.08-6.89; p<0.0001), private insurance (OR=5.02; 95% CI=2.26-11.12; p<0.0001), and elective admission type (OR=4.12; 95% CI=1.65-10.32; p=0.0025) were predictive of increased receipt of a 3+ level fusion in CSM. No other variables, including patient age, race, income, or admission source were predictive of either increased or decreased likelihood of receiving fusion of at least three levels for CSM. In conclusion, female sex, private insurance status, and elective admission type are each independent predictors in CSM for receipt of a 3+ level fusion, while patient age, race and income are not. Given the propensity of fusions greater than three levels to require posterior approaches and the association between posterior CSM approaches and increased morbidity/mortality, these findings may prove useful as to which patient demographics are predictive of increased morbidity and mortality in operative treatment of CSM.

Introduction: Blood loss is a major concern in spine surgery. Blood transfusion promotes oxygen delivery and tissue perfusion during long, complex surgeries, yet carries with it rare but notable risks. The hemoglobin (Hb) trigger-the Hb value that initiates clinician administration of packed red blood cells (PRBCs)-is frequently used to evaluate physician compliance with existing transfusion guidelines. Randomized clinical trials have demonstrated similar or improved outcomes among patients receiving blood transfusions using a restrictive Hb trigger-defined as an intraoperative Hb level of <10 g/dL intraoperatively or <8 g/dL postoperatively-versus a liberal Hb trigger (>=10 g/dL intraoperatively or >=8 g/dL postoperatively) in cardiac and hip surgery. To the authors' knowledge, no study has examined the associated morbidity and financial impact of liberal transfusions within spinal surgery. We thus aimed to determine the perioperative clinical outcomes and costs associated with liberal versus restrictive transfusion triggers among spine surgery patients. Material and Methods: The surgical billing database at our institution was queried for inpatients discharged following spinal surgery between 2008 and 2015, yielding 33,043 patients. Patients were stratified into eight groups according to the spine surgical procedure performed. The values used were the reported institutional acquisition cost ($220/unit) and a mean estimated activity-based cost ($760/unit) based on a Society for the Advancement of Blood Management report. Outcomes considered included mortality, in-hospital morbidity, total costs, and length of stay. Results: A total of 6,931 patients met the inclusion criteria. PRBC transfusions occured in 2,374 patients (at least 1 unit of PRBCs), yielding an overall transfusion rate of 34.3%. Compared to the other surgical groups, most PRBC use occurred within posterior lumbar fusion patients. The mean intraoperative Hb trigger was 10.1 (SD = 1.7) g/dL and the mean postoperative Hb trigger was 10.1 (SD = 2.1) g/dL. For the 2,374 patients that were transfused with PRBCs, 1420 (59.8%) received a postoperative PRBC transfusion with a liberal postoperative Hb trigger (>=8 g/dL) while 529 (22.3%) received an intraoperative PRBC transfusion with a liberal intraoperative Hb trigger (>=10 g/dL). Logistic regression analysis revealed that patients with a nadir Hb of 8-10 g/dL transfused with PRBC had an independently higher risk of perioperative morbidity (odds ratio [OR] = 2.12; 95% confidence interval [CI], 1.24-3.64; P = .006). The additional cost when comparing restrictive and liberal transfusion triggers was estimated to be between $1,330,439 and $4,596,062 (58.7% of the estimated total cost of PRBC transfusion), with the cost varying by surgery type. When comparing liberal and restrictive PRBC transfusion triggers, an estimated additional $202,675 to $700,151 in institutional costs were incurred each year among patients undergoing spine surgery. Conclusion: Patients with a nadir Hb of 8 to 10 g/dL who were transfused had higher perioperative morbidity, even after adjusting for potential confounders. The additional cost incurred from liberal transfusion trigger reliance ranged from an estimated $202,675 to $700,151 annually. These findings point to a potential area for clinicians and institutions to improve patient outcomes and reduce costs

Introduction: Despite the potential for profound impact of adult cervical deformity (ACD) on function and healthrelated quality of life, there remains a paucity of highquality studies that assess outcomes of surgical treatment for these patients. Our objective was to assess outcomes following surgical treatment for ACD based on a prospective multicenter consecutive case series. Materials and Methods: Surgically treated ACD patients eligible for 1-year followup were identified from a prospectively collected multicenter database. Baseline deformity characteristics, surgical parameters, and 1-year outcomes were assessed. Standardized outcome measures included: Neck Disability Index (NDI, range 0-100), neck pain numeric rating scale (NRS) score (range 0-10), and EQ-5D index (range 0 -1) and subscores (range 1-3). Paired sample t-tests were used to compare 1-year and baseline measures. Results: Of 77 ACD patients, 55 (71%) had 1-year follow-up (64% women, mean age 61 years, mean Charlson Comorbidity Index [CCI] of 0.6, previous cervical surgery in 44%). Diagnoses included: cervical sagittal imbalance (62%), cervical kyphosis (60%), proximal junctional kyphosis (8%), and coronal deformity (10%). Posterior fusion was performed in 85% (mean number of vertebral levels=10), and anterior fusion was performed in 29% (mean number of vertebral levels = 5). Three-column osteotomy was performed in 24% of patients. Mean operative time was 6.5 hours and mean estimated blood loss was 0.9L. At 1-year following surgery, ACD patients had significant improvement in NDI (50.5 to 38.0, P < .001), neck pain NRS (6.9 to 4.3, P < .001), EQ-5D index (0.51 to 0.66, P < .001), and EQ-5D subscores: mobility (1.9 to 1.7, P = .019), usual activities (2.2 to 1.9, P = .007), pain/discomfort (2.4 to 2.1, P < .001), anxiety/depression (1.8 to 1.5, P = .014). A nonsignificant trend favoring improvement was observed for EQ-5D self-care (1.5 to 1.3, P = .070). Compared with patients that achieved 1-year follow-up, those lost to followup did not differ significantly with regard to age, gender, CCI, number of fused anterior or posterior vertebral levels, or baseline NDI, neck pain NRS, or EQ-5D scores. Conclusions: Based on a prospective multicenter series of adults with cervical deformity, surgical treatment provided significant improvement in multiple measures of pain and function, including the NDI, neck pain NRS score, and EQ-5D. Further follow-up will be necessary to assess the durability of these surgical procedures and the resulting improved outcomes

Introduction: Although adult cervical deformity (ACD) has been empirically associated with significant pain and disability, the magnitude of this negative impact has not been objectively quantified. Our objective was to assess whether symptomatic ACD patients have substantial negative health impact based on the EQ-5D compared with United States (U.S.) normative and chronic disease state values. Materials and Methods: ACD patients presenting for surgical evaluation and treatment were identified from a prospectively collected multicenter database. Baseline demographics, deformity characteristics, and EQ-5D scores were collected. EQ-5D scores were compared with ageand gender-matched U.S. normative and chronic disease state values. Results: Of 121 ACD patients, 115 (95%) completed the EQ-5D (61% women, mean age 61 years, previous cervical surgery in 46%). Diagnoses included: cervical sagittal malalignment (63%), cervical kyphosis (60%), proximal junctional kyphosis (9%) and coronal deformity (8%). The mean EQ-5D index was 0.511, which is 35% below the bottom 25th percentile score (0.790) for a similar age- and gender-weighted normative population and worse than the bottom 25th percentile for several other chronic disease states (diabetes [0.708], ischemic heart disease [0.708], and myocardial infarction [0.575]). The EQ-5D index of 0.511 seen in this ACD cohort is comparable to the bottom 25th percentile for blindness (0.543), emphysema (0.508) and heart failure (0.437). Based on EQ-5D subscores, patients reported impact on mobility (87%), daily self-care (47%), daily activities (91%), pain/discomfort (98%), and anxiety/depression (67%). Conclusions: The health impact of symptomatic ACD is substantial, with an EQ-5D index that is 35% below the bottom 25th percentile for an age- and gender-matched normative U.S. population. The markedly negative health impact of ACD was demonstrated across all domains of the EQ-5D. The overall mean EQ-5D index for ACD patients was worse than the bottom 25th percentile for several other chronic disease states, including chronic ischemic heart disease, malignant breast cancer, and malignant prostate cancer, and was comparable to the bottom 25th percentile values for blindness/low vision, emphysema, renal failure, and stroke