Distal junctional kyphosis in adult cervical deformity patients: where does it occur?

PURPOSE: To evaluate the impact of the lowest instrumented vertebra (LIV) on Distal Junctional kyphosis (DJK) incidence in adult cervical deformity (ACD) surgery. METHODS: Prospectively collected data from ACD patients undergoing posterior or anterior-posterior reconstruction at 13 US sites was reviewed up to 2-years postoperatively (n = 140). Data was stratified into five groups by level of LIV: C6-C7, T1-T2, T3-Apex, Apex-T10, and T11-L2. DJK was defined as a kyphotic increase > 10° in Cobb angle from LIV to LIV-1. Analysis included DJK-free survival, covariate-controlled cox regression, and DJK incidence at 1-year follow-up. RESULTS: 25/27 cases of DJK developed within 1-year post-op. In patients with a minimum follow-up of 1-year (n = 102), the incidence of DJK by level of LIV was: C6-7 (3/12, 25.00%), T1-T2 (3/29, 10.34%), T3-Apex (7/41, 17.07%), Apex-T10 (8/11, 72.73%), and T11-L2 (4/8, 50.00%) (p < 0.001). DJK incidence was significantly lower in the T1-T2 LIV group (adjusted residual = -2.13), and significantly higher in the Apex-T10 LIV group (adjusted residual = 3.91). In covariate-controlled regression using the T11-L2 LIV group as reference, LIV selected at the T1-T2 level (HR = 0.054, p = 0.008) or T3-Apex level (HR = 0.081, p = 0.010) was associated with significantly lower risk of DJK. However, there was no difference in DJK risk when LIV was selected at the C6-C7 level (HR = 0.239, p = 0.214). CONCLUSION: DJK risk is lower when the LIV is at the upper thoracic segment than the lower cervical segment. DJK incidence is highest with LIV level in the lower thoracic or thoracolumbar junction.

Does the presence of cervical deformity in patients with baseline mild myelopathy increase operative urgency in adult cervical spinal surgery? A retrospective analysis.

OBJECTIVE: The objective of this study was to assess whether delaying surgical management of cervical deformity (CD) in patients with concomitant mild myelopathy increases the risk of suboptimal outcomes. METHODS: Patients aged ≥ 18 years who had a baseline diagnosis of mild myelopathy with baseline and up to 2 years of postoperative data were assessed. Patients were categorized as having CD (CD+) or not (CD-) at baseline. Patients with symptoms of myelopathy for more than 1 year after the initial visit prior to surgery were considered delayed. Clinical and radiographic data were assessed using means comparison analyses. Multivariate regression analysis assessed correlations between increasing time to surgery and peri- and postoperative outcomes adjusted for baseline age and frailty score. Backstep logistic regression analysis assessed the risk of complications or reoperation, while controlling for baseline T1 slope minus cervical lordosis (TS-CL). RESULTS: One hundred six patients were included (mean age 58.11 ± 11.97 years, 48% female, mean BMI 29.13 ± 6.89). Of the patients with baseline mild myelopathy, 22 (20.8%) were CD- while 84 (79.2%) were CD+. Overall, 9.5% of patients were considered to have delayed surgery. Linear regression revealed that both CD- and CD+ patients were more likely to require reoperation when there was more time between the initial visit and surgical admission (p < 0.001). Additionally, an adjusted logistic regression indicated that CD+ patients who had a greater length of time to surgery had a higher likelihood for major complications (p < 0.001). Conversely, CD+ patients who were operated on within 30 days of the initial visit had a significantly lower risk for a major complication (OR 0.901, 95% CI 0.889-1.105, p = 0.043), and a lower risk for reoperation (OR 0.954, 95% CI 0.877-1.090, p = 0.043), while controlling for the severity of deformity based on baseline TS-CL. CONCLUSIONS: The findings of this study demonstrate that a delay in surgery after the initial visit significantly increases the risk for major complications and reoperation in patients with CD with associated mild baseline myelopathy. Early operative treatment in this patient population may lower the risk of postoperative complications.

"Reverse roussouly": cervicothoracic curvature ratios define characteristic shapes in adult cervical deformity.

PURPOSE: To investigate normal curvature ratios of the cervicothoracic spine and to establish radiographic thresholds for severe myelopathy and disability, within the context of shape. METHODS: Adult cervical deformity (CD) patients undergoing cervical fusion were included. C2-C7 Cobb angle (CL) and thoracic kyphosis (TK), using T2-T12 Cobb angle, were used as a ratio, ranging from -1 to + 1. Pearson bivariate r and univariate analyses analyzed radiographic correlations and differences in myelopathy(mJOA > 14) or disability(NDI > 40) across ratio groups. RESULTS: Sixty-three CD patients included. Regarding CL:TK ratio, 37 patients had a negative ratio and 26 patients had a positive ratio. A more positive CL:TK correlated with increased TS-CL(r = 0.655, p = < 0.001)and mJOA(r = 0.530, p = 0.001), but did not correlate with cSVA/SVA or NDI scores. A positive CL:TK ratio was associated with moderate disability(NDI > 40)(OR: 7.97[1.22-52.1], p = 0.030). Regression controlling for CL:TK ratio revealed cSVA > 25 mm increased the odds of moderate to severe myelopathy and cSVA > 30 mm increased the odds of significant neck disability. Lastly, TS-CL > 29 degrees increased the odds of neck disability by 4.1 × with no cutoffs for severe mJOA(p > 0.05). CONCLUSIONS: Cervical deformity patients with an increased CL:TK ratio had higher rates of moderate neck disability at baseline, while patients with a negative ratio had higher rates of moderate myelopathy clinically. Specific thresholds for cSVA and TS-CL predicted severe myelopathy or neck disability scores, regardless of baseline neck shape. A thorough evaluation of the cervical spine should include exploration of relationships with the thoracic spine and may better allow spine surgeons to characterize shapes and curves in cervical deformity patients.

Health-related quality of life measures in adult spinal deformity: can we replace the SRS-22 with PROMIS?

PURPOSE: To determine the validity and responsiveness of PROMIS metrics versus the SRS-22r questionnaire in adult spinal deformity (ASD). METHODS: Surgical ASD patients undergoing ≥ 4 levels fused with complete baseline PROMIS and SRS-22r data were included. Internal consistency (Cronbach's alpha) and test-retest reliability [intraclass correlation coefficient (ICC)] were compared. Cronbach's alpha and ICC values ≥ 0.70 were predefined as satisfactory. Convergent validity was evaluated via Spearman's correlations. Responsiveness was assessed via paired samples t tests with Cohen's d to assess measure of effect (baseline to 3 months). RESULTS: One hundred and ten pts are included. Mean baseline SRS-22r score was 2.62 ± 0.67 (domains = Function: 2.6, Pain: 2.5, Self-image: 2.2, Mental Health: 3.0). Mean PROMIS domains = Physical Function (PF): 12.4, Pain Intensity (PI): 91.7, Pain Interference (Int): 55.9. Cronbach's alpha, and ICC were not satisfactory for any SRS-22 and PROMIS domains. PROMIS-Int reliability was low for all SRS-22 domains (0.037-0.225). Convergent validity demonstrated strong correlation via Spearman's rho between PROMIS-PI and overall SRS-22r (- 0.61), SRS-22 Function (- 0.781), and SRS-22 Pain (- 0.735). PROMIS-PF had strong correlation with SRS-22 Function (0.643), while PROMIS-Int had moderate correlation with SRS-22 Pain (- 0.507). Effect size via Cohen's d showed that PROMIS had superior responsiveness across all domains except for self-image. CONCLUSIONS: PROMIS is a valid measure compared to SRS-22r in terms of convergent validity, and has greater measure of effect in terms of responsiveness, but failed in reliability and internal consistency. Surgeons should consider the lack of reliability and internal consistency (despite validity and responsiveness) of the PROMIS to SRS-22r before replacing the traditional questionnaire with the computer-adaptive testing.

Artificial intelligence clustering of adult spinal deformity sagittal plane morphology predicts surgical characteristics, alignment, and outcomes.

PURPOSE: AI algorithms have shown 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 sagittal anatomical spinopelvic landmarks. We hypothesized that an AI algorithm would cluster preoperative lateral radiographs into groups with distinct morphology. METHODS: This was a retrospective review of a multicenter, prospectively collected database of adult spinal deformity. A total of 915 patients with adult spinal deformity and preoperative lateral radiographs were included. A 2 × 3, self-organizing map-a form of artificial neural network frequently employed in unsupervised classification tasks-was developed. The mean spine shape was plotted for each of the six clusters. Alignment, surgical characteristics, and outcomes were compared. RESULTS: Qualitatively, clusters C and D exhibited only mild sagittal plane deformity. Clusters B, E, and F, however, exhibited marked positive sagittal balance and loss of lumbar lordosis. Cluster A had mixed characteristics, likely representing compensated deformity. Patients in clusters B, E, and F disproportionately underwent 3-CO. PJK and PJF were particularly prevalent among clusters A and E. Among clusters B and F, patients who experienced PJK had significantly greater positive sagittal balance than those who did not. CONCLUSIONS: This study clustered preoperative lateral radiographs of ASD patients into groups with highly distinct overall spinal morphology and association with sagittal alignment parameters, baseline HRQOL, and surgical characteristics. The relationship between SVA and PJK differed by cluster. This study represents significant progress toward incorporation of computer vision into clinically relevant classification systems in adult spinal deformity. LEVEL OF EVIDENCE IV: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Predictors of long-term opioid dependence in transforaminal lumbar interbody fusion with a focus on pre-operative opioid usage.

PURPOSE: Predictors of long-term opioid usage in TLIF patients have not been previously explored in the literature. We examined the effect of pre-operative narcotic use in addition to other predictors of the pattern and duration of post-operative narcotic usage. METHODS: We conducted a retrospective cohort study at a single academic institution of patients undergoing a one- or two-level primary TLIF between 2014 and 2017. Total oral morphine milligram equivalents (MMEs) for inpatient use were calculated and used as the common unit of comparison. RESULTS: A multivariate binary logistic regression (R2 = 0.547, specificity 95%, sensitivity 58%) demonstrated that a psychiatric or chronic pain diagnosis (OR 3.95, p = 0.013, 95% CI 1.34-11.6), pre-operative opioid use (OR 8.65, p < 0.001, 95% CI 2.59-29.0), ASA class (OR 2.95, p = 0.025, 95% CI 1.14-7.63), and inpatient total MME (1.002, p < 0.001, 95% CI 1.001-1.003) were positive predictors of prolonged opioid use at 6-month follow-up, while inpatient muscle relaxant use (OR 0.327, p = 0.049, 95% CI 0.108-0.994) decreased the probability of prolonged opioid use. Patients in the pre-operative opioid use group had a significantly higher rate of opioid usage at 6 weeks (79% vs. 46%, p < 0.001), 3 months (51% vs. 14%, p < 0.001), and 6 months (40% vs. 5%, p < 0.001). CONCLUSIONS: Pre-operative opioid usage is associated with higher total inpatient opioid use and a significantly higher risk of long-term opiate usage at 6 months. Approximately 40% of pre-operative narcotic users will continue to consume narcotics at 6-month follow-up, compared with 5% of narcotic-naïve patients. These slides can be retrieved under Electronic Supplementary Material.

The spino-pelvic ratio: a novel global sagittal parameter associated with clinical outcomes in adult spinal deformity patients.

PURPOSE: Analysis of interactions of spinal alignment metrics may uncover novel alignment parameters, similar to PI-LL. This study utilized a data-driven approach to hypothesis generation by testing all possible division interactions between spinal alignment parameters. METHODS: This study was a retrospective cohort analysis. In total, 1439 patients with baseline ODI were included for hypothesis generation. In total, 666 patients had 2-year postoperative follow-up and were included for validation. All possible combinations of division interactions between baseline metrics were assessed with linear regression against baseline ODI. RESULTS: From 247 raw alignment metrics, 32,398 division interactions were considered in hypothesis generation. Conceptually, the TPA divided by PI is a measure of the relative alignment of the line connecting T1 to the femoral head and the line perpendicular to the sacral endplate. The mean TPA/PI was 0.41 at baseline and 0.30 at 2 years postoperatively. Higher TPA/PI was associated with worse baseline ODI (p < 0.0001). The change in ODI at 2 years was linearly associated with the change in TPA/PI (p = 0.0172). The optimal statistical grouping of TPA/PI was low/normal (≤ 0.2), medium (0.2-0.4), and high (> 0.4). The R-squared for ODI against categorical TPA/PI alone (0.154) was directionally higher than that for each of the individual Schwab modifiers (SVA: 0.138, PI-LL 0.111, PT 0.057). CONCLUSION: This study utilized a data-driven approach for hypothesis generation and identified the spino-pelvic ratio (TPA divided by PI) as a promising measure of sagittal spinal alignment among ASD patients. Patients with SPR > 0.2 exhibited inferior ODI scores. LEVEL OF EVIDENCE: III.

Atlantoaxial dislocation with congenital "sandwich fusion" in the craniovertebral junction: a retrospective case series of 70 patients.

BACKGROUND: In the setting of congenital C1 occipitalization and C2-3 fusion, significant strain is placed on the atlantoaxial joint. Vertebral fusion both above and below the atlantoaxial joint (i.e., a "sandwich") creates substantial instability. We retrospectively report on a case series of "sandwich fusion" atlantoaxial dislocation (AAD), describing the associated clinical characteristics and detailing surgical treatment. To the best of our knowledge, the present study is the largest investigation to date of this congenital subgroup of AAD. METHODS: Seventy consecutive patients with sandwich fusion AAD, from one senior surgeon, were retrospectively reviewed. The clinical features and the surgical treatment results were assessed using descriptive statistics. No funding sources or potential conflict of interest-associated biases exist. RESULTS: The mean patient age was 42.2 years (range: 5-77 years); 36 patients were male, and 34 were female. Fifty-eight patients (82.9%) had myelopathy, with Japanese Orthopaedic Association (JOA) scores ranging 4-16 (mean: 12.9). Cranial neuropathy was involved in 10 cases (14.3%). The most common presentation age group was 31 to 40 years (24 cases, 34.3%). Radiological findings revealed brainstem and/or cervical-medullar compression (58 cases, 82.9%), syringomyelia (16 cases, 22.9%), Chiari malformation (12 cases, 17.1%), cervical spinal stenosis (10 cases, 14.3%), high scapula deformity (1 case, 1.4%), os odontoideum (1 case, 1.4%), and dysplasia of the atlas (1 case, 1.4%). Computed tomography angiography was performed in 27 cases, and vertebral artery (VA) anomalies were identified in 14 cases (51.9%). All 70 patients underwent surgical treatment, without spinal cord or VA injury. Four patients (5.7%) suffered complications, including 1 wound infection, 1 screw loosening, and 2 cases of bulbar paralysis. In the 58 patients with myelopathy, the mean JOA score increased from 12.9 to 14.5. The average follow-up time was 50.5 months (range: 24-120 months). All 70 cases achieved solid atlantoaxial fusion at the final follow-up. CONCLUSIONS: Sandwich fusion AAD, a unique subgroup of AAD, has distinctive clinical features and associated malformations such as cervical-medullar compression, syringomyelia, and VA anomalies. Surgical treatment of AAD was associated with myelopathy improvement and minimal complication occurrence.

Adult Lumbar Disk Herniation: Diagnosis, Treatment, Complications, Outcomes, and Evidence-Based Data for Patient and Health Professional Counseling.

Symptomatic lumbar disk herniation is abundantly common in adult patients and can cause significant pain and disability in those affected. Both surgical and nonsurgical treatment options exist for the management of this heterogeneous condition; thus, it is important that surgeons and other healthcare providers understand the appropriate indications for surgical treatment of patients with lumbar disk herniation. Though there is still lack of consensus regarding the optimal treatment of lumbar disk herniation in all situations, many principles and preferred techniques are agreed upon in the literature. In this chapter, we provide an in-depth overview of the anatomy and pathophysiology, natural history, physical examination, treatment decision making, surgical treatment options, and postoperative complications pertaining to lumbar disk herniation.

The Dubousset Functional Test is a Novel Assessment of Physical Function and Balance.

BACKGROUND: Currently, the functional status of patients undergoing spine surgery is assessed with quality-of-life questionnaires, and a more objective and quantifiable assessment method is lacking. Dr. Jean Dubousset conceptually proposed a four-component functional test, but to our knowledge, reference values derived from asymptomatic individuals have not yet been reported, and these are needed to assess the test's clinical utility in patients with spinal deformities. QUESTIONS/PURPOSES: (1) What are the reference values for the Dubousset Functional Test (DFT) in asymptomatic people? (2) Is there a correlation between demographic variables such as age and BMI and performance of the DFT among asymptomatic people? METHODS: This single-institution prospective study was performed from January 1, 2018 to May 31, 2018. Asymptomatic volunteers were recruited from our college of medicine and hospital staff to participate in the DFT. Included participants did not report any musculoskeletal problems or trauma within 5 years. Additionally, they did not report any history of lower limb fracture, THA, TKA, or patellofemoral arthroplasty. Patients were also excluded if they reported any active medical comorbidities. Demographic data collected included age, sex, BMI, and self-reported race. Sixty-five asymptomatic volunteers were included in this study. Their mean age was 42 ± 15 years; 27 of the 65 participants (42%) were women. Their mean BMI was 26 ± 5 kg/m. The racial distribution of the participants was 34% white (22 of 65 participants), 25% black (16 of 65 participants), 15% Asian (10 of 65 participants), 9% subcontinental Indian (six of 65 participants), 6% Latino (four of 65 participants), and 10% other (seven of 65 participants). In a controlled setting, participants completed the DFT after verbal instruction and demonstration of each test, and all participants were video recorded. The four test components included the Up and Walking Test (unassisted sit-to-stand from a chair, walk forward/backward 5 meters [no turn], then unassisted stand-to-sit), Steps Test (ascend three steps, turn, descend three steps), Down and Sitting Test (stand-to-ground, followed by ground-to-stand, with assistance as needed), and Dual-Tasking Test (walk 5 meters forwards and back while counting down from 50 by 2). Tests were timed, and data were collected from video recordings to ensure consistency. Reference values for the DFT were determined via a descriptive analysis, and we calculated the mean, SD, 95% CI, median, and range of time taken to complete each test component, with univariate comparisons between men and women for each component. Linear correlations between age and BMI and test components were studied, and the frequency of verbal and physical pausing and adverse events was noted. RESULTS: The Up and Walking Test was completed in a mean of 15 seconds (95% CI, 14-16), the Steps Test was completed in 6.3 seconds (95% CI, 6.0-6.6), the Down and Sitting Test was completed in 6.0 seconds (95% CI, 5.4-6.6), and the Dual-Tasking Test was performed in 13 seconds (95% CI, 12-14). The length of time it took to complete the Down and Sitting (r = 0.529; p = 0.001), Up and Walking (r = 0.429; p = 0.001), and Steps (r = 0.356; p = 0.014) components increased with as the volunteer's age increased. No correlation was found between age and the time taken to complete the Dual-Tasking Test (r = 0.134; p = 0.289). Similarly, the length of time it took to complete the Down and Sitting (r = 0.372; p = 0.005), Up and Walking (r = 0.289; p = 0.032), and Steps (r = 0.366; p = 0.013) components increased with increasing BMI; no correlation was found between the Dual-Tasking Test's time and BMI (r = 0.078; p = 0.539). CONCLUSIONS: We found that the DFT could be completed by asymptomatic volunteers in approximately 1 minute, although it took longer for older patients and patients with higher BMI. CLINICAL RELEVANCE: We believe, but did not show, that the DFT might be useful in assessing patients with spinal deformities. The normal values we calculated should be compared in future studies with those of patients before and after undergoing spine surgery to determine whether this test has practical clinical utility. The DFT provides objective metrics to assess function and balance that are easy to obtain, and the test requires no special equipment.

Correction to: Prior bariatric surgery lowers complication rates following spine surgery in obese patients.

The AHRQ (Agency for Healthcare Research and Quality) has requested the correction of the result Tables 1-3 of this study: All stated numbers below 10 shall be modified to read "<10" instead.

Congenital Etiology Is an Independent Risk Factor for Complications in Adolescents Undergoing Corrective Scoliosis Surgery: Comparison of In-hospital Comorbidities Using Nationwide KID's Inpatient Database.

BACKGROUND: Congenital scoliosis (CS) is associated with more rigid, complex deformities relative to adolescent idiopathic scoliosis (AIS) which theoretically increases surgical complications. Despite extensive literature studying AIS patients, few studies have been performed on CS patients. The purpose of this study was to evaluate complications associated with spinal fusions for CS and AIS. METHODS: A retrospective review of the Kid's Inpatient Database (KID) years 2000 to 2009 was performed. Inclusion: patients under 20 years with ICD-9 diagnosis codes for idiopathic scoliosis (IS-without concomitant congenital anomalies) and CS, undergoing spinal fusion from the KID years 2000 to 2009. Two analyses were performed according to age below 10 years and 10 years and above. Univariate analysis described differences in demographics, comorbidities, intraoperative complications, and clinical values between groups. Binary logistic regression controlling for age, sex, race, and invasiveness predicted complications risk in CS (odds ratios; 95% confidence interval). RESULTS: In total, 25,131 patients included (IS, n=22443; CS, n=2688). For patients under age 10, CS patients underwent 1 level shorter fusions (P<0.001), had fewer comorbidities (P<0.001), and sustained similar complication incidence. In the 10 and over age analysis, CS patients similarly had shorter fusions, but greater comorbidities, and significantly more complications (odds ratio, 1.6; confidence interval, 1.4-1.8). CONCLUSIONS: CS patients have higher in-hospital complication rates. With more comorbidities, these patients have increased risk of sustaining procedure-related complications such as shock, infection, and Adult Respiratory Distress Syndrome. These data help to counsel patients and their families before spinal fusion. LEVEL OF EVIDENCE: Level III-retrospective review of a prospectively collected database.

Incidence of Congenital Spinal Abnormalities Among Pediatric Patients and Their Association With Scoliosis and Systemic Anomalies.

BACKGROUND: Congenital abnormalities when present, according to VACTERL theory, occur nonrandomly with other congenital anomalies. This study estimates the prevalence of congenital spinal anomalies, and their concurrence with other systemic anomalies. METHODS: A retrospective cohort analysis on Health care Cost and Utilization Project's Kids Inpatient Database (KID), years 2000, 2003, 2006, 2009 was performed. ICD-9 coding identified congenital anomalies of the spine and other body systems. OUTCOME MEASURES: Overall incidence of congenital spinal abnormalities in pediatric patients, and the concurrence of spinal anomaly diagnoses with other organ system anomalies. Frequencies of congenital spine anomalies were estimated using KID hospital-and-year-adjusted weights. Poisson distribution in contingency tables tabulated concurrence of other congenital anomalies, grouped by body system. RESULTS: Of 12,039,432 patients, rates per 100,000 cases were: 9.1 hemivertebra, 4.3 Klippel-Fiel, 56.3 Chiari malformation, 52.6 tethered cord, 83.4 spina bifida, 1.2 absence of vertebra, and 6.2 diastematomyelia. Diastematomyelia had the highest concurrence of other anomalies: 70.1% of diastematomyelia patients had at least one other congenital anomaly. Next, 63.2% of hemivertebra, and 35.2% of Klippel-Fiel patients had concurrent anomalies. Of the other systems deformities cooccuring, cardiac system had the highest concurrent incidence (6.5% overall). In light of VACTERL's definition of a patient being diagnosed with at least 3 VACTERL anomalies, hemivertebra patients had the highest cooccurrence of ≥3 anomalies (31.3%). With detailed analysis of hemivertebra patients, secundum ASD (14.49%), atresia of large intestine (10.2%), renal agenesis (7.43%) frequently cooccured. CONCLUSIONS: Congenital abnormalities of the spine are associated with serious systemic anomalies that may have delayed presentations. These patients continue to be at a very high, and maybe higher than previously thought, risk for comorbidities that can cause devastating perioperative complications if not detected preoperatively, and full MRI workups should be considered in all patients with spinal abnormalities. LEVEL OF EVIDENCE: Level III.

Prospective multi-centric evaluation of upper cervical and infra-cervical sagittal compensatory alignment in patients with adult cervical deformity.

PURPOSE: Reciprocal mechanisms for standing alignment have been described in thoraco-lumbar deformity but have not been studied in patients with primary cervical deformity (CD). The purpose of this study is to report upper- and infra-cervical sagittal compensatory mechanisms in patients with CD and evaluate their changes post-operatively. METHODS: Global spinal alignment was studied in a prospective database of operative CD patients. Inclusion criteria were any of the following: cervical kyphosis (CK) > 10°, cervical scoliosis > 10°, cSVA (C2-C7 Sagittal vertical axis) > 4 cm or CBVA (Chin Brow Vertical Angle) > 25°. For this study, patients who had previous fusion outside C2 to T4 segments were excluded. Patients were sub-classified by increasing severity of cervical kyphosis [CL (cervical lordosis): < 0°, CK-low 0°-10°, CK-high > 10°] and cSVA (cSVA-low 0-4 cm, cSVA-mid 4-6 cm, cSVA-high > 6 cm) and were compared for pre- and 3-month post-operative regional and global sagittal alignment to determine compensatory recruitment. RESULTS: 75 CD patients (mean age 61.3 years, 56% women) were included. Patients with progressively larger CK had a progressive increase in C0-C2 (CL = 34°, CK-low = 37°, CK-high = 44°, p = 0.004), C2Slope and T1Slope-CL (p < 0.05). As the cSVA increased, there was progressive increase in C2Slope, T1Slope and TS-CL (p < 0.05) and patients compensated through increasing C0-C2 (cSVA-low = 33°, cSVA-mid = 40°, cSVA-high = 43°, p = 0.007) and pelvic tilt (cSVA-low = 14.9°, cSVA-mid = 24.1°, cSVA-high = 24.9°, p = 0.02). At 3 months post-op, with significant improvement in cervical alignment, there was relaxation of C0-C2 (39°-35°, p = 0.01) which positively correlated with magnitude of deformity correction. CONCLUSIONS: Patients with cervical malalignment compensate with upper cervical hyper-lordosis, presumably for the maintenance of horizontal gaze. As cSVA increases, patients also tend to exhibit increased pelvic retroversion. Following surgical treatment, there was relaxation of upper cervical compensation.

Lumbosacral stress and age may contribute to increased pelvic incidence: an analysis of 1625 adults.

PURPOSE: While there is a consensus that pelvic incidence (PI) remains constant after skeletal maturity, recent reports argue that PI increases after 60 years. This study aims to investigate whether PI increases with age and to determine potential associated factors. METHODS: 1510 patients with various spinal degenerative and deformity pathologies were enrolled, along with an additional 115 asymptomatic volunteers. Subjects were divided into six age subgroups with 10-year intervals. RESULTS: PI averaged 54.1° in all patients. PI was significantly higher in the 45-54-year age group than 35-44-year age group (55.8° vs. 49.7°). There were significant PI differences between genders after age 45. Linear regression revealed age, gender and malalignment as associated factors for increased PI with R 2 of 0.22 (p < 0.001). CONCLUSIONS: PI is higher in female patients and in older patients, especially those over 45 years old. Spinal malalignment also may have a role in increased PI due to increased L5-S1 bending moment.

Three types of sagittal alignment regarding compensation in asymptomatic adults: the contribution of the spine and lower limbs.

PURPOSE: A comprehensive understanding of normative sagittal profile is necessary for adult spinal deformity. Roussouly described four sagittal alignment types based on sacral slope, lumbar lordosis, and location of lumbar apex. However, the lower limb, a newly described component of spinal malalignment compensation, is missing from this classification. This study aims to propose a full-body sagittal profile classification in an asymptomatic population based on full-body imaging. METHODS: This is a retrospective analysis of a prospective single-center study of 116 asymptomatic volunteers. Cluster analysis including all sagittal parameters was first performed, and then ANOVA was performed between sub-clusters to eliminate the non-significantly different parameters. This loop was repeated until all parameters were significantly different between each sub-cluster. RESULTS: Three types of full-body sagittal profiles were finalized according to cluster analysis with ten radiographic parameters: hyperlordosis type (77 subjects), neutral type (28 subjects), and compensated type (11 subjects). Radiographic parameters included knee angle, pelvic shift, pelvic angle, PT, PI-LL, C7-S1 SVA, TPA, T1 slope, C2-C7 angle, and C2-C7 SVA. Age was significantly different across compensation types, while BMI and gender were comparable. Age-matched subjects were randomly selected with 11 subjects in each type. ANOVA analysis revealed that all parameters but PT and C2-C7 angle remained significantly different. CONCLUSIONS: The current three compensation types of full-body sagittal profiles in asymptomatic adults included significant changes from cervical region to knee, indicating that subjects should be evaluated with full-length imaging. All three types exist regardless of age, but the distribution may vary.

Complications in Patients Undergoing Spinal Fusion After THA.

INTRODUCTION: Patients with lumbar spine and hip disorders may, during the course of their treatment, undergo spinal fusion and THA. There is disagreement among prior studies regarding whether patients who undergo THA and spinal fusion are at increased risk of THA dislocation and other hip-related complications. QUESTIONS / PURPOSES: Is short or long spinal fusion associated with an increased rate of postoperative complications in patients who underwent a prior THA? PATIENTS AND METHODS: A retrospective study of New York State's Department of Health database (SPARCS) was performed. SPARCS has a unique identification code for each patient, allowing investigators to track the patient across multiple admissions. The SPARCS dataset spans visit data of patients of all ages and races across urban and rural locations. The SPARCs dataset encompasses all facilities covered under New York State Article 28 and uses measures to further representative reporting of data concerning all races. Owing to the nature of the SPARCS dataset, we are unable to comment on data leakage, as there is no way to discern between a patient who does not subsequently seek care and a patient who seeks care outside New York State. ICD-9-Clinical Modification codes identified adult patients who underwent elective THA from 2009 to 2011. Patients who had subsequent spinal fusion (short: 2-3 levels, or long: ≥ 4 levels) with a diagnosis of adult idiopathic scoliosis or degenerative disc disease were identified. Forty-nine thousand nine hundred twenty patients met the inclusion criteria of the study. In our inclusion and exclusion criteria, there was no variation with respect to the distribution of sex and race across the three groups of interest. Patients who underwent a spinal procedure (short versus long fusion) had comparable age. However, patients who did not undergo a spinal procedure were older than patients who had short fusion (65 ± 12.4 years versus 63 ± 10.7 years; p < 0.001). Multivariate binary logistic regression models that controlled for age, sex, and Deyo/Charlson scores were used to investigate the association between spinal fusion and THA revisions, postoperative dislocation, contralateral THAs, and total surgical complications to the end of 2013. A total of 49,920 patients who had THAs were included in one of three groups (no subsequent spinal fusion: n = 49,209; short fusion: n = 478; long fusion: n = 233). RESULTS: Regression models revealed that short and long spinal fusions were associated with increased odds for hip dislocation, with associated odds ratios (ORs) of 2.2 (95% CI, 1.4-3.6; p = 0.002), and 4.4 (95% CI, 2.7-7.3; p < 0.001), respectively. Patients who underwent THA and spinal surgery also had an increased odds for THA revision, with ORs of 2.0 (95% CI, 1.4-2.8; p < 0.001) and 3.2 (95% CI, 2.1-4.8; p < 0.001) for short and long fusion, respectively. However, spinal fusions were not associated with contralateral THAs. Further, short and long spinal fusions were associated with increased surgical complication rates (OR = 2.8, 95% CI, 2.1-3.8, p < 0.001; OR = 5.3, 95% CI, 3.8-7.4, p < 0.001, respectively). CONCLUSION: We showed that spinal fusion in adults is associated with an increased frequency of complications and revisions in patients who have had a prior THA. Specifically, patients who had a long spinal fusion after THA had 340% higher odds of experiencing a hip dislocation and 220% higher odds of having to undergo a revision THA. Further research is necessary to determine whether this relationship is associated with the surgical order, or whether more patient-specific surgical goals of revision THA should be developed for patients with a spinal deformity. LEVEL OF EVIDENCE: Level III, therapeutic study.

Development of a validated computer-based preoperative predictive model for pseudarthrosis with 91% accuracy in 336 adult spinal deformity patients.

OBJECTIVEPseudarthrosis can occur following adult spinal deformity (ASD) surgery and can lead to instrumentation failure, recurrent pain, and ultimately revision surgery. In addition, it is one of the most expensive complications of ASD surgery. Risk factors contributing to pseudarthrosis in ASD have been described; however, a preoperative model predicting the development of pseudarthrosis does not exist. The goal of this study was to create a preoperative predictive model for pseudarthrosis based on demographic, radiographic, and surgical factors.METHODSA retrospective review of a prospectively maintained, multicenter ASD database was conducted. Study inclusion criteria consisted of adult patients (age ≥ 18 years) with spinal deformity and surgery for the ASD. From among 82 variables assessed, 21 were used for model building after applying collinearity testing, redundancy, and univariable predictor importance ≥ 0.90. Variables included demographic data along with comorbidities, modifiable surgical variables, baseline coronal and sagittal radiographic parameters, and baseline scores for health-related quality of life measures. Patients groups were determined according to their Lenke radiographic fusion type at the 2-year follow-up: bilateral or unilateral fusion (union) or pseudarthrosis (nonunion). A decision tree was constructed, and internal validation was accomplished via bootstrapped training and testing data sets. Accuracy and the area under the receiver operating characteristic curve (AUC) were calculated to evaluate the model.RESULTSA total of 336 patients were included in the study (nonunion: 105, union: 231). The model was 91.3% accurate with an AUC of 0.94. From 82 initial variables, the top 21 covered a wide range of areas including preoperative alignment, comorbidities, patient demographics, and surgical use of graft material.CONCLUSIONSA model for predicting the development of pseudarthrosis at the 2-year follow-up was successfully created. This model is the first of its kind for complex predictive analytics in the development of pseudarthrosis for patients with ASD undergoing surgical correction and can aid in clinical decision-making for potential preventative strategies.

Cluster analysis describes constellations of cardiac anomalies presenting in spinal anomaly patients.

BACKGROUND: Cardiac anomalies are prevalent in patients with bony spinal anomalies. Prior studies evaluating incidences of bony congenital anomalies of the spine are limited. The Kids' Inpatient Database (KID) yields national discharge estimates of rare pediatric conditions like congenital disorders. This study utilized cluster analysis to study patterns of concurrent vertebral anomalies, anal atresia, cardiac malformations, trachea-esophageal fistula, renal dysplasia, and limb anomalies (VACTERL anomalies) co-occurring in patients with spinal congenital anomalies. METHODS: Retrospective review of KID 2003-2012. KID-supplied hospital- and year-adjusted weights allowed for incidence assessment of bony spinal anomalies and cardiac, gastrointestinal, urinary anomalies of VACTERL. K-means clustering assessed relationships between most frequent anomalies within bony spinal anomaly discharges; k set to n - 1(n = first incidence of significant drop/little gain in sum of square errors within clusters). RESULTS: There were 12,039,432 KID patients 0-20 years. Incidence per 100,000 discharges: 2.5 congenital fusion of spine, 10.4 hemivertebra, 7.0 missing vertebra. The most common anomalies co-occurring with bony vertebral malformations were atrial septal defect (ASD 12.3%), large intestinal atresia (LIA 11.8%), and patent ductus arteriosus (PDA 10.4%). Top congenital cardiac anomalies in vertebral anomaly patients were ASD, PDA, and ventricular septal defect (VSD); all three anomalies co-occur at 6.6% rate in this vertebral anomaly population. Cluster analysis revealed that of bony anomaly discharges, 55.9% of those with PDA had ASD, 34.2% with VSD had PDA, 22.9% with LIA had ASD, 37.2% with ureter obstruction had LIA, and 35.5% with renal dysplasia had LIA. CONCLUSIONS: In vertebral anomaly patients, the most common co-occurring congenital anomalies were cardiac, renal, and gastrointestinal. Top congenital cardiac anomalies in vertebral anomaly patients were ASD, PDA, and VSD. VACTERL patients with vertebral anomalies commonly presented alongside cardiac and renal anomalies.

Prior bariatric surgery lowers complication rates following spine surgery in obese patients.

BACKGROUND: Bariatric surgery (BS) is an increasingly common treatment for morbid obesity that has the potential to effect bone and mineral metabolism. The effect of prior BS on spine surgery outcomes has not been well established. The aim of this study was to assess differences in complication rates following spinal surgery for patients with and without a history of BS. METHODS: Retrospective analysis of the prospectively collected New York State Inpatient Database (NYSID) years 2004-2013. BS patients and morbidly obese patients (non-BS) were divided into cervical and thoracolumbar surgical groups and propensity score matched for age, gender, and invasiveness and complications compared. RESULTS: One thousand nine hundred thirty-nine spine surgery patients with a history of BS were compared to 1625 non-BS spine surgery patients. The average time from bariatric surgery to spine surgery is 2.95 years. After propensity score matching, 740 BS patients were compared to 740 non-BS patients undergoing thoracolumbar surgery, with similar comorbidity rates. The overall complication rate for BS thoracolumbar patients was lower than non-BS (45.8% vs 58.1%, P < 0.001), with lower rates of device-related (6.1% vs 23.2%, P < 0.001), DVT (1.2% vs 2.7%, P = 0.039), and hematomas (1.5% vs 4.5%, P < 0.001). Neurologic complications were similar between BS patients and non-BS patients (2.3% vs 2.7%, P = 0.62). For patients undergoing cervical spine surgery, BS patients experienced lower rates of bowel issues, device-related, and overall complication than non-BS patients (P < 0.05). CONCLUSIONS: Bariatric surgery patients undergoing spine surgery experience lower overall complication rates than morbidly obese patients. This study warrants further investigation into these populations to mitigate risks associated with spine surgery for bariatric patients.