Faculty Bibliography

OBJECTIVE The goal of this study was to compare inpatient morbidity and mortality after adult spinal deformity (ASD) surgery in teaching versus nonteaching hospitals in the US. METHODS The Nationwide Inpatient Sample was used to identify surgical patients with ASD between 2002 and 2011. Only patients > 21 years old and elective cases were included. Patient characteristics, inpatient morbidity, and inpatient mortality were compared between teaching and nonteaching hospitals. A multivariable logistic regression analysis was performed to examine the effect of hospital teaching status on surgical outcomes. RESULTS A total of 7603 patients were identified, with 61.2% (n = 4650) in the teaching hospital group and 38.8% (n = 2953) in the nonteaching hospital group. The proportion of patients undergoing revision procedures was significantly different between groups (5.2% in teaching hospitals vs 3.9% in nonteaching hospitals, p = 0.008). Likewise, complex procedures (defined as fusion of 8 or more segments and/or osteotomy) were more common in teaching hospitals (27.3% vs 21.7%, p < 0.001). Crude overall complication rates were similar in teaching hospitals (47.9%) compared with nonteaching hospitals (49.8%, p = 0.114). After controlling for patient characteristics, case complexity, and revision status, patients treated at teaching hospitals were significantly less likely to develop a complication when compared with patients treated at a nonteaching hospital (OR 0.89; 95% CI 0.82-0.98). The mortality rate was 0.4% in teaching hospitals and < 0.4% in nonteaching hospitals (p = 0.210). CONCLUSIONS Patients who undergo surgery for ASD at a teaching hospital may have significantly lower odds of complication development compared with patients treated at a nonteaching hospital.

PURPOSE: This nationwide study identifies ASD surgical risk factors for morbidity/mortality. METHODS: NIS discharges from 2001 to 2010 aged 25+ with scoliosis diagnoses, 4+ levels fused, and procedural codes for anterior and/or posterior thoracic and/or lumbar spinal fusion and refusion were included. Demographics, comorbidities and procedure-related complications were determined for each subgroup (degenerative, congenital, idiopathic, other). Multivariate analysis reported as [OR (95 % CI)]. RESULTS: 11,982 discharges were identified. Morbidity, excluding device-related, and mortality rates were 50.81 and 0.28 %, respectively. Certain comorbidities were associated with increased morbidity/mortality: congestive heart failure (CHF) [1.62 (1.42-1.84)] [5.67 (3.30-9.73)], coagulopathy [3.52 (3.22-3.85)] [2.32 (1.44-3.76)], electrolyte imbalance [2.65 (2.52-2.79)] [4.63 (3.15-6.81)], pulmonary circulation disorders [9.45 (7.45-11.99)] [8.94 (4.43-18.03)], renal failure [1.29 (1.13-1.47)] [5.51 (2.57-11.82)], and pathologic weight loss [2.38 (2.01-2.81)] [7.28 (4.36-12.14)]. Chronic pulmonary disease was associated with higher morbidity [1.08 (1.02-1.14)]; liver disease was linked to increased mortality [36.09 (16.16-80.59)]. 9+ level fusions had increased morbidity vs 4-8 level fusions [1.69 (1.61-1.78)] and refusions [1.08 (1.02-1.14)]. Idiopathic scoliosis was associated with decreased morbidity vs all other subgroups [0.85 (0.80-0.91)]. Age >65 was associated with increased morbidity and mortality vs 25-64 group [1.09 (1.05-1.14)] [3.49 (2.31-5.29)]. Females had increased morbidity [1.18 (1.13-1.23)] and decreased mortality [0.30 (0.21-0.44)]. Mean comorbidity index (0.55) and age (64.38) for degenerative cohort were higher vs all other subgroups (P < 0.0001). CONCLUSIONS: Longer fusions were associated with increased morbidity. Age >65 was associated with increased morbidity/mortality, while females were associated with increased morbidity but decreased mortality. Idiopathic scoliosis had decreased morbidity. Degenerative ASD cases had higher comorbidity indices, potentially due to older age. This study is clinically useful for patient education, surgical decision-making, and optimizing patient outcomes.

BACKGROUND: Some studies have suggested patients who undergo surgery in July have worse outcomes compared to patients treated during other months. The purpose of this study is to compare inpatient morbidity and mortality among patients who underwent adult spinal deformity (ASD) surgery in July with those who underwent surgery in other months. METHODS: Admission data for patients who underwent ASD surgery were extracted from the Nationwide Inpatient Sample for the years 2002 to 2011. Only adult patients (over 21 years of age) and elective admissions to teaching hospitals were included. A multivariable regression analysis was performed to examine the independent effect of July admissions on overall complications, major complications, and inpatient mortality. RESULTS: A total of 27,794 patients were identified, with 2,023 (7.8%) admitted in July and 25,771 (92.2%) in other months. Overall complication rates in July (43.1%) were not different from rates in other months (44.9%, p=0.468). Similarly, major complication rates were similar; 12.9% in July and 12.4% in other months (p=0.764). Mortality was not different between groups (p=0.807). After multivariable analysis, July admissions were not found to increase the odds of developing any complication (OR 0.94; 95% CI, 0.77 - 1.12; p=0.403), major complications (OR 1.04; 95% CI, 0.76 - 1.41; p=0.788) or inpatient mortality (OR 1.35; 95% CI, 0.31 - 5.84; p=0.684). CONCLUSION: In this study of a nationwide database, patients who underwent ASD surgery in July did not have increased odds of developing a complication or inpatient mortality compared to patients admitted in other months.

STUDY DESIGN: Retrospective multicenter database review. OBJECTIVE: The aim of this study was to evaluate national postoperative outcomes and hospital characteristics trends from 2001 to 2010 for advanced age CSM patients. SUMMARY OF BACKGROUND DATA: Recent studies show increases in US cervical spine surgeries and CSM diagnoses. However, few have compared national outcomes for elderly and younger CSM patients. METHODS: A Nationwide Inpatient Sample (NIS) analysis from 2001 to 2010, including CSM patients 25+ who underwent anterior and/or posterior cervical fusion or laminoplasty. Fractures, 9+ levels fused, or any cancers were excluded. Measures included demographics, outcomes, and hospital-related data for 25 to 64 versus 65+ and 65 to 75 versus 76+ age groups. Univariate and logistic regression modeling evaluated procedure-related complications risk in 65+ and 76+ age groups (OR[95% CI]). RESULTS: Discharges for 35,319 patients in the age range of 25 to 64 years and 19,097 at the age 65+ years were identified. Average comorbidity indices for patients at 65+ years were higher compared to the 25 to 64 years age group (0.79 vs. 0.0.44, P < 0.0001), as was the total complications rate (11.39% vs. 5.93%, P < 0.0001) and charges ($57,449.94 vs. $49,951.11, P < 0.0001). Hospital course for aged 65+ patients was longer (4.76 vs. 3.26 days, P < 0.0001). Mortality risk was higher in the 65+ cohort (3.38[2.93-3.91]), adjusted for covariates. 65+ patients had increased risk of all complications except device-related, for which they had decreased risk (0.61[0.56-0.67]). Patients 76+ years displayed increased hospital charges ($59,197.60 vs. $56,601.44, P < 0.001) and courses (5.77 vs. 4.28 days, P < 0.001) compared to those in the age group 65 to 75 years. These same patients presented with increased Deyo scores (0.83 vs. 0.77, P < 0.001), had increased total complications rate (13.87% vs. 10.20%, P < 0.001), and displayed increased risk for postoperative shock (6.34 [11.16-3.60], P < 0.001), digestive system (1.92 [2.40-1.54], P < 0.001), and wound dehiscence (1.71 [2.56-1.15], P < 0.001). CONCLUSION: Patients aged 65+ years undergoing CSM surgical management have a higher mortality risk, more procedure-related complications, higher comorbidity burden, longer hospital course, and higher charges. This study provides clinically useful data for surgeons to educate patients and to improve outcomes.

STUDY DESIGN: Retrospective case series of atlantoaxial rotatory fixed dislocation (AARFD). OBJECTIVE: To describe clinical features and the surgical treatment of AARFD. SUMMARY OF BACKGROUND DATA: The classification and treatment strategy for atlantoaxial rotatory fixation (AARF) were previously described and remained controversial. AARF concomitant with atlantoaxial dislocation has different clinical features and treatment strategy with the most AARF. Due to deficiency of the transverse ligament or odontoid, the atlantoaxial remains instable even after the torticollis relieved or cured. Because of the rarity, treatment strategy for this special condition has not been specialized and fully explored in the literatures. METHODS: 32 children with AARFD (sustained torticollis more than six weeks and ADI more than 5 mm) were retrospectively reviewed. Treatment methodology, pearls, and pitfalls of the treatment were discussed. RESULTS: Thirty-two cases had sustained torticollis for an average of 5.7 months. ADI of them ranged from 8 to 22 mm, with a mean of 11.3 mm. Eight cases presented with signs and symptoms of spinal cord dysfunction. All 32 cases underwent surgery and had no spinal cord or vertebral artery injury. The surgery included posterior reduction and fusion (reducible dislocation and torticollis, 16 cases), and transoral release followed by posterior reduction and fusion (irreducible dislocation and torticollis, 16 cases). The average follow-up time was 42 months. Solid fusion and torticollis healing were achieved in 31 patients (96.9%) as detected radiologically. Two cases (6.3%, 2/32) suffered complications (CSF leakage and recurred torticollis followed by revision). CONCLUSION: AARFD had distinct clinical features relative to common presentations of AARF. Because of deficiency of the transverse ligament or odontoid and subsequent atlantoaxial dislocation, surgical treatments are applied for this condition, including transoral release and posterior C1-2 reduction and fusion. AARFD cases were successfully managed surgically without pre-operative traction, with few complications seen. LEVEL OF EVIDENCE: 4.

STUDY DESIGN: Measurement reliability study of adult spinal deformity (ASD) patient radiographs using intraclass correlation coefficients (ICC) and variance. OBJECTIVE: The aim of the study was to compare picture archiving and communication systems (PACS) to dedicated spine measurement software (SMS). SUMMARY OF BACKGROUND DATA: Accurate radiographic measurement of sagittal alignment is essential for evaluating ASD. PACS measurements often necessitate rudimentary techniques and estimations of anatomic landmarks and angles. Though SMS has been studied and validated, no studies directly compare PACS to SMS. METHODS: Eleven independent observers (7 spine surgeons, 4 researchers) digitally measured 20 ASD radiographs for pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), PI-LL, thoracic kyphosis (TK), and sagittal vertical axis (SVA). Round 1 used PACS basic line/angle tools; Round 2 used a validated SMS that automatically calculates spino-pelvic parameters from 6 user-identified landmarks. Means, coefficient of variance (CV), and intraclass correlation coefficients (ICC) were analyzed. RESULTS: PACS measurements were significantly greater than SMS (PI, PT, PI-LL: P < 0.0001), though within clinical and measurement margins of error. Excluding TK, the variations in measurement (CV) were significantly greater for PACS (14-34%) vs. SMS (11-23%). Reliability was greater in SMS than PACS for PI, PT, PI-LL, LL, and SVA. The greatest differences in intraclass correlation coefficients (ICC) between PACS and SMS were in PI (PACS: 0.647; SMS: 0.810) and PI-LL (PACS: 0.921; SMS: 0.970). Among surgeons, the differences between PACS and SMS were augmented, and SMS had higher intraclass correlation coefficients (ICC) than PACS for all parameters (mean intraclass correlation coefficients [ICC] 0.931 vs. 0.861). Among surgeons, PI had the lowest reliability ( PACS: 0.505; SMS: 0.752) and SVA had the highest ( PACS: 0.985; SMS: 0.994). CONCLUSION: SMS provides significantly more reliable measurements than PACS, especially among surgeons. Consistent use of SMS in the evaluation and surgical planning of ASD patients appears necessary given the significant differences in values, variance, and reliability between PACS and SMS. LEVEL OF EVIDENCE: 3.

STUDY DESIGN: A retrospective subgroup analysis was performed on surgically treated patients from the lumbar spinal stenosis (SpS) arm of the Spine Patient Outcomes Research Trial (SPORT), randomized and observational cohorts. OBJECTIVE: To identify risk factors for reoperation in patients treated surgically for SpS and compare outcomes between patients who underwent reoperation with those that did not. SUMMARY OF BACKGROUND DATA: SpS is one of the most common indications for surgery in the elderly; however, few long-term studies have identified risk factors for reoperation. METHODS: A post-hoc subgroup analysis was performed on patients from the SpS arm of the Spine Patient Outcomes Research Trial (SPORT), randomized and observational cohorts. Baseline characteristics were analyzed between reoperation and no reoperation groups using univariate and multivariate analysis on data eight years post-operation. RESULTS: Of the 417 study patients, 88% underwent decompression only, 5% non-instrumented fusion and 6% instrumented fusion. At the 8 year follow up, the reoperation rate was 18%; 52% of reoperations were for recurrent stenosis or progressive spondylolisthesis, 25% for complication or other reason and 16% for new condition. Of patients who underwent a reoperation, 42% did so within 2 yrs, 70% within 4 years and 84% within 6 years. Patients who underwent reoperation were less likely to have presented with any neurological deficit (43% reop vs. 57% no reop, p = 0.04). Patients improved less at follow-up in the re-operation group (p < 0.001). CONCLUSION: In patients undergoing surgical treatment for SpS, the reoperation rate at eight year follow-up was 18%. Patients with a reoperation were less likely to have a baseline neurological deficit. Patients who did not undergo reoperation had better patient reported outcomes at eight year follow up compared to those who had repeat surgery. LEVEL OF EVIDENCE: 2.

OBJECT A high prevalence of cervical deformity (CD) has been identified among adult patients with thoracolumbar spinal deformity undergoing surgical treatment. The clinical impact of this is uncertain. This study aimed to quantify the differences in patient-reported outcomes among patients with adult spinal deformity (ASD) based on presence of CD prior to treatment. METHODS A retrospective review was conducted of a multicenter prospective database of patients with ASD who underwent surgical treatment with 2-year follow-up. Patients were grouped by the presence of preoperative CD: 1) cervical positive sagittal malalignment (CPSM) C2-7 sagittal vertical axis >/= 4 cm; 2) cervical kyphosis (CK) C2-7 angle > 0; 3) CPSM and CK (BOTH); and 4) no baseline CD (NONE). Health-related quality of life (HRQOL) scores included the Physical Component Summary and Mental Component Summary (PCS and MCS) scores of the 36-Item Short Form Health Survey (SF-36), Oswestry Disability Index (ODI), Scoliosis Research Society-22 questionnaire (SRS-22), and minimum clinically important difference (MCID) of these scores at 2 years. Standard radiographic measurements were conducted for cervical, thoracic, and thoracolumbar parameters. RESULTS One hundred eighty-two patients were included in this study: CPSM, 45; CK, 37; BOTH, 16; and NONE, 84. Patients with preoperative CD and those without had similar baseline thoracolumbar radiographic measurements and similar correction rates at 2 years. Patients with and without preoperative CD had similar baseline HRQOL and on average both groups experienced some HRQOL improvement. However, those with preoperative CPSM had significantly worse postoperative ODI, PCS, SRS-22 Activity, SRS-22 Appearance, SRS-22 Pain, SRS-22 Satisfaction, and SRS-22 Total score, and were less likely to meet MCID for ODI, PCS, SRS-22 Activity, and SRS-22 Pain scores with the following ORs and 95% CIs: ODI 0.19 (0.07-0.58), PCS 0.17 (0.06-0.47), SRS-22 Activity 0.23 (0.09-0.62), SRS-22 Pain 0.20 (0.08-0.53), and SRS-22 Appearance 0.34 (0.12-0.94). Preoperative CK did not have an effect on outcomes. Interestingly, despite correction of the thoracolumbar deformity, 53.3% and 51.4% of patients had persistent CPSM and persistent CK, respectively. CONCLUSIONS Patients with thoracolumbar deformity without preoperative CD are likely to have greater improvements in HRQOL after surgery than patients with concomitant preoperative CD. Cervical positive sagittal alignment in adult patients with thoracolumbar deformity is strongly associated with inferior outcomes and failure to reach MCID at 2-year follow-up despite having similar baseline HRQOL to patients without CD. This was the first study to assess the impact of concomitant preoperative cervical malalignment in adult patients with thoracolumbar deformity. These results can help surgeons educate patients at risk for inferior outcomes and direct future research to identify an etiology and improve patient outcomes. Investigation into the etiology of the baseline cervical malalignment may be warranted in patients who present with thoracolumbar deformity.

BACKGROUND CONTEXT: Adult spinal deformity (ASD) patients may gain a MCID in one or more of the HRQOL instruments without surgical intervention. This study identifies baseline characteristics of this subset of non-operative patients and proposes predictors of those most likely to benefit. PURPOSE: Determine factors that affect likelihood of non-operative patients to reach minimum clinically important difference (MCID). STUDY DESIGN/SETTING: Retrospective review of prospective, multi-center database. PATIENT SAMPLE: Non-operative ASD patients. OUTCOME MEASURES: Health-related quality of life measures (HRQOL), including the Scoliosis Research Society (SRS)-22 questionnaire. METHODS: Multicenter database of 215 non-operative patients with ASD and minimum 2-year follow-up. Using a multivariate analysis, two groups were compared to identify possible predictors: those that reached an MCID in SRS Pain or Activity (n=86) at 2 years, and those who did not reach MCID (n=129). Subgroup multivariate analysis of patients with a deficit (potential improvement) in both SRS Pain and Activity (n=84) was performed. Data collection was supported by a grant from Depuy for the International Spine Study Group Foundation. RESULTS: At baseline, the non-operative patients that reached MCID had a significantly lower SRS Pain score (3.0 vs 3.6), smaller thoracolumbar (TL) Cobb angle (29.6 degrees vs. 36.5 degrees ; 87 patients with SRS-Schwab classification Lumbar or Double), sacral slope (33.1 degrees vs. 36.4 degrees ), and less lumbar lordosis (46.5 degrees vs. 52.8 degrees ) (all P<0.05). SRS Pain and TL Cobb were significant predictors of reaching MCID. PI-LL was significant on univariate analysis but not by multivariate (7.5 degrees vs. 2.6 degrees ; P=0.14). In the subset of severely disabled patients, worse vertebral obliquity was a predictor for not achieving MCID (P<0.05). CONCLUSIONS: Non-operative ASD patients who achieved an MCID in SRS Activity or Pain had a lower baseline SRS Pain Score and less coronal deformity in the TL region. Greater baseline pain offers significant room for potential improvement, which may be important in identifying ASD patients who have the potential to reach an MCID non-operatively. Coronal deformities in the TL region, and associated vertebral obliquity may negatively impact improvement potential with non-operative care.

BACKGROUND: Older age has been considered a relative contraindication to complex spinal procedures. Minimally invasive surgery (MIS) techniques to treat patients with adult spinal deformity (ASD) have emerged with the potential benefit of decreased approach-related morbidity. OBJECTIVE: To determine whether a minimal clinically important difference (MCID) could be achieved in patients aged >/=65 years with ASD who underwent MIS. METHODS: Multicenter database of patients who underwent MIS for ASD was queried. Outcome metrics assessed were ODI and VAS scores for back and leg pain. Based on published reports, MCID was defined as a positive change of 12.8 ODI, 1.2 VAS back pain, and 1.6 VAS leg pain. RESULTS: Forty-two patients were identified. Mean age was 70.3 years, 31 (73.8%) were female. Preoperatively, mean CC, PT, pelvic incidence to lumbar lordosis (PI-LL) mismatch, and SVA were 35 degrees , 24.6 degrees , 14.2 degrees , and 4.7 cm, respectively. Postoperatively, mean CC, PT, PI-LL, and SVA were 18 degrees , 25.4 degrees , 11.9 degrees , and 4.9 cm, respectively. Mean 5.0 levels were treated posteriorly, and mean 4.0 interbody fusions were performed. Mean ODI improved from 47.1 to 25.1. Mean VAS back and leg pain scores improved from 6.8 and 5.9 to 2.7 and 2.7, respectively. Mean follow-up was 32.1 months. For ODI, 64.3% of patients achieved MCID. For VAS back and leg pain, 82.9% and 72.2%, respectively, reached MCID. CONCLUSIONS: MCID represents the threshold where patients feel a meaningful clinical improvement has occurred. Our study results suggest that the majority of elderly patients with modest ASD can achieve MCID with MIS.