Accuracy of Phantomless Calibration of Routine Computed Tomography Scans for Opportunistic Osteoporosis Screening in the Spine Clinic.

STUDY DESIGN: Diagnostic accuracy study. OBJECTIVE: To establish a simple method of phantomless bone mineral density (BMD) measurement by using preoperative lumbar Computed Tomography (CT) scans, and compare the accuracy of reference tissue combinations to diagnose low BMD against uncalibrated Hounsfield units (HUs). SUMMARY OF BACKGROUND DATA: HUs are used as a measure of BMD; however, associations between HU and T-scores vary widely. Quantitative CT (qCT) scans are more accurate, but they require density calibration with an object of known density (phantom), which limits feasibility. As an emerging technique, phantomless (internal) calibration of routine CT scans may provide a good opportunity for screening. METHODS: Patients who were scheduled to undergo lumbar surgery, with a preoperative CT scan, and a dual-energy x-ray absorptiometry (DXA) scan within six months were included. Four tissues were selected for calibration: subcutaneous adipose (A), erector spinae (ES), psoas (P) and aortic blood (AB). The HUs of these tissues were used in linear regression against ground-truth values. Calibrations were performed by using two different internal tissues at a time to maintain simplicity and in-office applicability.Volumetric bone mineral densities (vBMD) derived from internally calibrated CT scans were analyzed for new threshold values for low bone density. Areas under the curve (AUC) were calculated with 95% confidence intervals (CI). RESULTS: 45 patients were included (M/F=10/35, mean age:63.3). Calibrated vBMDs had stronger correlations with DXA T-scores when compared with HUs, with L2 exhibiting the highest coefficients. Calibration by using A and ES with the threshold of 162 mg/cm3 had a sensitivity of 90% in detecting low BMD (AUC=0.671). CONCLUSIONS: This novel method allows simple, in-office calibration of routine preoperative CT scans without the use of a phantom. Calibration using adipose and erector spinae with a threshold of 162 mg/cm3 is proposed for low bone density screening with high sensitivity (90%). LEVEL OF EVIDENCE: Level III.

Proximal Junctional Degeneration and Failure Modes: A Novel Classification and Clinical Implications.

STUDY DESIGN: Case-control study. OBJECTIVE: To introduce a classification system that will include the major types of degenerative changes and failures related to the proximal junction, and to determine the clinical course and characteristics for the different types of proximal junctional degeneration (PJD). SUMMARY OF BACKGROUND DATA: Proximal junctional kyphosis (PJK) and failures are well recognized after adult spinal fusion, however, a standardized classification is lacking. METHODS: The proposed system identified four different patterns of PJD: Type 1 (multi-level symmetrical collapse), Type 2 (Single adjacent level collapse), Type 3 (fracture) and Type 4 (spondylolisthesis). A single center database was reviewed from 2018 to 2021. Patients ≥18 years of age, who underwent posterior spinal fusion of ≥3 levels with an upper instrumented vertebral level between T8-L2, and a follow-up of ≥2 years were included. Radiographic measurements, revision surgery and time to revision were the primary outcomes. RESULTS: 150 patients were included with a mean age of 65.1 (±9.8) years and a mean follow-up of 3.2 (±1) years. 69 patients (46%) developed significant degenerative changes in the proximal junction, and were classified accordingly. 20 (13%) were Type 1, 17 (11%) were Type 2, 22 (15%) were Type 3 and 10 (7%) were Type 4. Type 3 had a significantly shorter time to revision with a mean of 0.9 (±0.9) years. Types 3 and 4 had greater preoperative sagittal vertical axis, and Types 1 and 3 had greater final follow-up lumbar lordosis. Bone density measured by Hounsfield units showed lower measurements for Type 3. Types 1 and 4 had lower rates of developing PJK. Type 1 had the lowest revision rate with 40% (types 2, 3 and 4 were 77%, 73% and 80%, respectively, P=0.045). CONCLUSION: This novel classification system defines different modes of degeneration and failures at the proximal junction, and future studies with larger sample sizes are needed for validation. LEVEL OF EVIDENCE: 3.

Comparison of No Tap (two-step) and tapping robotic assisted cortical bone trajectory screw insertion.

Workflow for cortical bone trajectory (CBT) screws includes tapping line-to-line or under tapping by 1 mm. We describe a non-tapping, two-step workflow for CBT screw placement, and compare the safety profile and time savings to the Tap (three-step) workflow. Patients undergoing robotic assisted 1-3 level posterior fusion with CBT screws for degenerative conditions were identified and separated into either a No-Tap or Tap workflow. Number of total screws, screw-related complications, estimated blood loss, operative time, robotic time, and return to the operating room were collected and analyzed. There were 91 cases (458 screws) in the No-Tap and 88 cases (466 screws) in the Tap groups, with no difference in demographics, revision status, ASA grade, approach, number of levels fused or diagnosis between cohorts. Total robotic time was lower in the No-Tap (26.7 min) versus the Tap group (30.3 min, p = 0.053). There was no difference in the number of malpositioned screws identified intraoperatively (10 vs 6, p = 0.427), screws converted to freehand (3 vs 3, p = 0.699), or screws abandoned (3 vs 2, p = 1.000). No pedicle/pars fracture or fixation failure was seen in the No-Tap cohort and one in the Tap cohort (p = 1.00). No patients in either cohort were returned to OR for malpositioned screws. This study showed that the No-Tap screw insertion workflow for robot-assisted CBT reduces robotic time without increasing complications.

Intra-Operative Hypotension is an Important Modifiable Risk Factor for Major Complications in Spinal Fusion Surgery.

STUDY DESIGN: Retrospective observational cohort. OBJECTIVES: This study explores the impact of Intraoperative hypotension (IOH)on post-op complications for major thoracolumbar spine fusion procedures. SUMMARY OF BACKGROUND DATA: IOH with mean arterial pressure (MAP) < 65 mmHg is associated with post-op acute kidney injury (AKI) in general surgery. In spinal deformity surgery, IOH is a contributing factor to MEP changes and spinal cord dysfunction with deformity correction. METHODS: 539 thoracolumbar fusion cases, > 6 surgical levels and > 3 hours duration were identified. Anesthetic/surgical data included OR time, fluid volume, blood loss, blood product replacement and use of vasopressors. Arterial-line based MAP data was collected at 1 min intervals. Cummulative duration of MAP < 65 mmHg was recorded. IOH within the first hour of surgery vs. the entire case was determined. Post-op course and complications including SSI, GI complications, pulmonary complications, MI, DVT, PE, AKI and encephalopathy were noted. Cumulative complications were grouped as none, 1-2 complications, or >3 complications. RESULTS: There was a significant association between occurrence of complications and duration of IOH within the first hour of surgery (8.2 vs. 5.6 min, P<0.001) and across the entire procedure (28.1 vs. 19.3 min, P=0.008). This association persisted for individual major complications including SSI, acute respiratory failure, PE, ileus requiring NGT and post-operative cognitive dysfunction. Comparison of patients with 0 vs. 1-2 vs. 3 or more complications demonstrated that patients with 3 or more complications had a longer duration of IOH in the first hour of the surgery and that patients who had no complications received less vasopressor than patients who had 1-2 or 3 or more complications. CONCLUSION: This study identifies duration of IOH during the first hour of surgery as a previously unrecognized modifiable risk associated with major complications for multi-level lumbar fusion surgery.

Immediate Postoperative Change in the Upper Instrumented Screw-Vertebra Angle Is a Predictor for Proximal Junctional Kyphosis and Failure.

STUDY DESIGN: Retrospective review. OBJECTIVES: To determine if change in position of upper instrumented vertebral (UIV) screw between intraoperative prone and immediate postoperative standing radiographs is a predictor for proximal junctional kyphosis or failure (PJK/PJF). SUMMARY OF BACKGROUND DATA: Cranially directed UIV screws on post-operative radiographs have been found to be associated with PJK. Change in the screw position between intraoperative and immediate postoperative radiographs has not been studied. METHODS: Patients with posterior fusion ≥3 levels and UIV at or distal to T8, and minimum 2-year follow-up were identified from a single center database. Primary outcomes were radiographic PJK/PJF or revision for PJK/PJF. Demographic, surgical and radiographic variables, including intraoperative screw-vertebra (S-V) angle, change in S-V angle, direction of UIV screw (cranial-neutral-caudal) and rod-vertebra (R-V) angle were collected. RESULTS: 143 cases from 110 patients were included with a mean age of 62.9 years and a follow-up of 3.5 years. 54 (38%) cases developed PJK/PJF, of whom 30 required a revision. Mean S-V angle was -0.9°±5.5° intraoperative and -2.8°±5.5° postoperative. The group with PJK/PJF had a mean S-V angle change of -2.5°±2.4 while the rest had a change of -1.0°±1.6 (P=0.010). When the change in S-V angle was <5°, 33% developed PJK, this increased to 80% when it was ≥5° (P=0.001). Revision for PJK/PJF increased from 16% to 60% when S-V angle changed ≥5° (P=0.001). Regression analysis showed S-V angle change as a significant risk factor for PJK/PJF (P=0.047, OR=1.58) and for revision due to PJK/PJF (P=0.009, OR=2.21). CONCLUSIONS: Change in the S-V angle from intraop prone to immediate postop standing radiograph is a strong predictor for PJK/PJF and for revision. For each degree of S-V angle change, odds of revision for PJK/PJF increases by 2.2x. A change of 5° should alert the surgeon to the likely development of PJK/PJF requiring revision.

Impact of educational background on preoperative disease severity and postoperative outcomes among patients with lumbar spondylolisthesis: a Quality Outcomes Database study.

OBJECTIVE: Deficiency in patient education has been correlated with increased disease-related morbidity and decreased access to care. However, the associations between educational level, preoperative disease severity, and postoperative outcomes in patients with lumbar spondylolisthesis have yet to be explored. METHODS: The spondylolisthesis dataset of the Quality Outcomes Database (QOD)-a cohort with prospectively collected data by the SpineCORe study team of the 12 highest enrolling sites with an 81% follow-up at 5 years -was utilized and stratified for educational level. Patients were classified into three categories (high school or less, graduate, or postgraduate). Patient-reported outcome measures (PROMs) documented at baseline and follow-up included Oswestry Disability Index (ODI) score, EQ-5D in quality-adjusted life years, and numeric rating scale (NRS) scores for back and leg pain. Disease severity was measured with PROMs. Postoperatively, patients also completed the North American Spine Society assessment to measure their satisfaction with surgery. Multivariable regression analysis was used to compare education level with disease severity and postoperative outcomes. RESULTS: A total of 608 patients underwent analysis, with 260 individuals (42.8%) at an educational level of high school or less. On univariate analysis, baseline disease severity was worse among patients with lower levels of education. On multivariable regression analysis, patients with postgraduate level of education had significantly lower ODI scores (ß = -3.75, 95% CI -7.31 to -0.2, p = 0.039) compared to graduates, while the other PROMs were not associated with significant differences at baseline. Five years postoperatively, patients from various educational backgrounds exhibited similar rates of minimal clinically important differences in PROMs. Nevertheless, patients with the lowest educational level had higher ODI scores (27.1, p < 0.01), lower EQ-5D scores (0.701, p < 0.01), and higher NRS leg pain (3.0, p < 0.01) and back pain (4.0, p < 0.01) scores compared to those with graduate or postgraduate levels of education. The odds for postoperative satisfaction were also comparable between cohorts at 5 years (reference, graduate level; high school or less, OR 0.87, 95% CI 0.46-1.64, p = 0.659; postgraduate, OR 1.6, 95% CI 0.7-3.65, p = 0.262). CONCLUSIONS: Lower patient education level was associated with a greater baseline disease severity in patients with lumbar spondylolisthesis. Surgery demonstrated similar benefits irrespective of educational background; however, individuals with lower educational level reported lower outcomes overall. This emphasizes the need for enhanced health literacy to mitigate disparities for reported outcomes.

Comparing posterior cervical foraminotomy with anterior cervical discectomy and fusion in radiculopathic patients: an analysis from the Quality Outcomes Database.

OBJECTIVE: The objective of this study was to compare clinical and patient-reported outcomes (PROs) between posterior foraminotomy and anterior cervical discectomy and fusion (ACDF) in patients presenting with cervical radiculopathy. METHODS: The Quality Outcomes Database was queried for patients who had undergone ACDF or posterior foraminotomy for radiculopathy. To create two highly homogeneous groups, optimal individual matching was performed at a 5:1 ratio between the two groups on 29 baseline variables (including demographic characteristics, comorbidities, symptoms, patient-reported scores, underlying pathologies, and levels treated). Outcomes of interest were length of stay, reoperations, patient-reported satisfaction, increase in EQ-5D score, and decrease in Neck Disability Index (NDI) scores for arm and neck pain as long as 1 year after surgery. Noninferiority analysis of achieving patient satisfaction and minimal clinically important difference (MCID) in PROs was performed with an accepted risk difference of 5%. RESULTS: A total of 7805 eligible patients were identified: 216 of these underwent posterior foraminotomy and were matched to 1080 patients who underwent ACDF. The patients who underwent ACDF had more underlying pathologies, lower EQ-5D scores, and higher NDI and neck pain scores at baseline. Posterior foraminotomy was associated with shorter hospitalization (0.5 vs 0.9 days, p < 0.001). Reoperations within 12 months were significantly more common among the posterior foraminotomy group (4.2% vs 1.9%, p = 0.04). The two groups performed similarly in PROs, with posterior foraminotomy being noninferior to ACDF in achieving MCID in EQ-5D and neck pain scores but also having lower rates of maximal satisfaction at 12 months (North American Spine Society score of 1 achieved by 65.2% posterior foraminotomy patients vs 74.6% of ACDF patients, p = 0.02). CONCLUSIONS: The two procedures were found to be offered to different populations, with ACDF being selected for patients with more complicated pathologies and symptoms. After individual matching, posterior foraminotomy was associated with a higher reoperation risk within 1 year after surgery compared to ACDF (4.2% vs 1.9%). In terms of 12-month PROs, posterior foraminotomy was noninferior to ACDF in improving quality of life and neck pain. The two procedures also performed similarly in improving NDI scores and arm pain, but ACDF patients had higher maximal satisfaction rates.

Risk Factors for Medial Breach During Robotic-Assisted Cortical Bone Trajectory Screw Insertion.

OBJECTIVE: We describe the incidence of, and identify the risk factors for, a medial breach of the pedicle wall during robotic-assisted cortical bone trajectory (RA-CBT) screw insertion. METHODS: We analyzed a consecutive series of adult patients who underwent RA-CBT screw placement from January 2019 to July 2022. To assess the pedicle wall medial breach, postoperative computed tomography (CT) images were analyzed. Patient demographic data and screw data were compared between patients with and without a medial breach. The Hounsfield units (HUs) on the L1 midvertebral axial CT scan was used to evaluate bone quality. RESULTS: Of 784 CBT screws in 145 patients, 30 (3.8%) had a medial breach in 23 patients (15.9%). One screw was grade 2, and the others were grade 1. Patients with a medial breach had a lower HU value compared with the patients without a medial breach (123.3 vs. 150.5; P = 0.027). A medial breach was more common in the right than left side (5.5% vs. 2.0%; P = 0.014). More than one half of the screws with a medial breach were found in the upper instrumented vertebra (UIV) compared with the middle construct or lowest instrumented vertebra (6.7% vs. 1.3% vs. 2.7%; P = 0.003). Binary logistic regression showed that low HU values, right-sided screw placement, and UIV were associated with a medial breach. No patients returned to the operating room for screw malposition. No differences were found in the clinical outcomes between patients with and without a medial breach. CONCLUSIONS: The incidence of pedicle wall medial breach was 3.8% of RA-CBT screws in the postoperative CT images. A low HU value measured in the L1 axial image, right-sided screw placement, and UIV were associated with an increased risk of medial breach for RA-CBT screw placement.

Cervical spondylotic myelopathy and driving abilities: defining the prevalence and long-term postoperative outcomes using the Quality Outcomes Database.

OBJECTIVE: Cervical spondylotic myelopathy (CSM) can cause significant difficulty with driving and a subsequent reduction in an individual's quality of life due to neurological deterioration. The positive impact of surgery on postoperative patient-reported driving capabilities has been seldom explored. METHODS: The CSM module of the Quality Outcomes Database was utilized. Patient-reported driving ability was assessed via the driving section of the Neck Disability Index (NDI) questionnaire. This is an ordinal scale in which 0 represents the absence of symptoms while driving and 5 represents a complete inability to drive due to symptoms. Patients were considered to have an impairment in their driving ability if they reported an NDI driving score of 3 or higher (signifying impairment in driving duration due to symptoms). Multivariable logistic regression models were fitted to evaluate mediators of baseline impairment and improvement at 24 months after surgery, which was defined as an NDI driving score < 3. RESULTS: A total of 1128 patients who underwent surgical intervention for CSM were included, of whom 354 (31.4%) had baseline driving impairment due to CSM. Moderate (OR 2.3) and severe (OR 6.3) neck pain, severe arm pain (OR 1.6), mild-moderate (OR 2.1) and severe (OR 2.5) impairment in hand/arm dexterity, severe impairment in leg use/walking (OR 1.9), and severe impairment of urinary function (OR 1.8) were associated with impaired driving ability at baseline. Of the 291 patients with baseline impairment and available 24-month follow-up data, 209 (71.8%) reported postoperative improvement in their driving ability. This improvement seemed to be mediated particularly through the achievement of the minimal clinically important difference (MCID) in neck pain and improvement in leg function/walking. Patients with improved driving at 24 months noted higher postoperative satisfaction (88.5% vs 62.2%, p < 0.01) and were more likely to achieve a clinically significant improvement in their quality of life (50.7% vs 37.8%, p < 0.01). CONCLUSIONS: Nearly one-third of patients with CSM report impaired driving ability at presentation. Seventy-two percent of these patients reported improvements in their driving ability within 24 months of surgery. Surgical management of CSM can significantly improve patients' driving abilities at 24 months and hence patients' quality of life.

The effect of myelography dye on bone density measurements utilizing Hounsfield units on CT.

OBJECTIVE: Hounsfield unit (HU) measurements of bone density on CT are increasingly used for preoperative planning in spine surgery. Postmyelogram CT is another common preoperative diagnostic study. However, there is no current literature evaluating whether HU measurements on CT are affected by the presence of myelography dye. The purpose of the current study was to determine if the presence of myelography dye affects HU measurements of bone density in CT studies. METHODS: Twenty-nine preoperative spine surgery patients who underwent both standard and postmyelography CT performed within 6 months of each other were identified. HU measurements were obtained from an elliptical region of interest using the available software on a standard PACS. Measurements were obtained on the axial cut at the midvertebral body on all lumbar vertebrae on three separate occasions and an average value was calculated for comparative analysis. A 6-week gap was used between measurements of the CT scans and the CT myelograms to diminish bias. RESULTS: The mean age of the cohort was 69 years and the average BMI was 32 kg/m2. Five patients were male and 24 were female. Six of the patients had instrumentation placed prior to the initial CT scan. The average HU measurements for CT levels L1-5 were 165, 171, 145, 154, and 225, respectively, whereas HU measurements for CT myelography of levels L1-5 were 168, 177, 148, 170, and 239, respectively. Strong correlations were noted between the HU measured on CT and CT myelography for L1 (r2 = 0.951), L2 (r2 = 0.966), L4 (r2 = 0.820), and L5 (r2 = 0.900), and moderate for L3 (r2 = 0.668). CONCLUSIONS: The presence of myelography dye had no clear effect on CT HU measurements of bone density. The results of this study support the use of CT myelograms for bone density assessment in the absence of standard CT images.

Staged circumferential lumbar fusions have less intraoperative complications and shorter operative time with no difference in 30-, 90-, and 1-year complications: a propensity-matched cohort analysis of 190 patients.

BACKGROUND CONTEXT: Circumferential lumbar fusions (cLFs) are becoming more common with increasing and more minimally invasive anterior access techniques. Staging allows reassessment of indirect decompression and alignment prior to the posterior approach, and optimization of OR time management. Safety of staging has been well documented in deformity surgery but has yet to be delineated in less extensive, degenerative cLFs. PURPOSE: The purpose of this study is to compare perioperative complications and outcomes between staged versus single-anesthetic circumferential fusions in the lumbar spine. STUDY DESIGN: Propensity-matched comparative observational cohort. PATIENT SAMPLE: Patients who underwent cLFs for lumbar degenerative disease. OUTCOME MEASURES: In-hospital, 30-day, 90-day, and 1-year complications. METHODS: From 123 patients undergoing single-anesthetic and 154 patients undergoing staged cLF, 95 patients in each group were propensity-matched based on age, sex, BMI, ASA score, smoking, revision, and number of levels. We compared perioperative, 30-day, 90-day, and 1-year complications between the two cohorts. RESULTS: Mean days between stages was 1.58. Single-anesthetic cLF had longer total surgery time (304 vs 240 minutes, p<.001) but shorter total PACU total time (133 vs 196 minutes, p<.001). However, there was no difference in total anesthesia time (368 vs 374 minutes, p=.661) and total EBL (357 vs 320cc, p=.313). Intraoperative complications were nine incidental durotomies in the single-anesthetic and one iliac vein injury in the staged group (9% vs 1%, p=.018). There was no difference of in-hospital (38 vs 31, p=.291), 30-day (16 vs 23, p=.281), 90-day (10 vs 15, p=.391), 1-year complications (9 vs 12, p=.644), and overall cumulative 1-year complications (54 vs 56, p=.883) between the two cohorts. CONCLUSIONS: There is a decrease in total surgical time and intraoperative complications during staged compared with single-anesthetic cLF with no difference in in-hospital, 30-day, 90-day, and 1-year complications between approaches.

Reliability of a Novel Classification System for Thoracic Disc Herniations.

STUDY DESIGN: This is a cross-sectional survey. OBJECTIVE: The aim was to assess the reliability of a proposed novel classification system for thoracic disc herniations (TDHs). SUMMARY OF BACKGROUND DATA: TDHs are complex entities varying substantially in many factors, including size, location, and calcification. To date, no comprehensive system exists to categorize these lesions. METHODS: Our proposed system classifies 5 types of TDHs using anatomic and clinical characteristics, with subtypes for calcification. Type 0 herniations are small (≤40% of spinal canal) TDHs without significant spinal cord or nerve root effacement; type 1 are small and paracentral; type 2 are small and central; type 3 are giant (>40% of spinal canal) and paracentral; and type 4 are giant and central. Patients with types 1 to 4 TDHs have correlative clinical and radiographic evidence of spinal cord compression. Twenty-one US spine surgeons with substantial TDH experience rated 10 illustrative cases to determine the system's reliability. Interobserver and intraobserver reliability were determined using the Fleiss kappa coefficient. Surgeons were also surveyed to obtain consensus on surgical approaches for the various TDH types. RESULTS: High agreement was found for the classification system, with 80% (range 62% to 95%) overall agreement and high interrater and intrarater reliability (kappa 0.604 [moderate to substantial agreement] and kappa 0.630 [substantial agreement], respectively). All surgeons reported nonoperative management of type 0 TDHs. For type 1 TDHs, most respondents (71%) preferred posterior approaches. For type 2 TDHs, responses were roughly equivalent for anterolateral and posterior options. For types 3 and 4 TDHs, most respondents (72% and 68%, respectively) preferred anterolateral approaches. CONCLUSIONS: This novel classification system can be used to reliably categorize TDHs, standardize description, and potentially guide the selection of surgical approach. Validation of this system with regard to treatment and clinical outcomes represents a line of future study.

Normative Bone Mineral Density Measured on Computed Tomography Scans in Children and Adolescents.

STUDY DESIGN: Retrospective chart review. OBJECTIVE: To provide reference values for Hounsfield unit (HU) measured on computed tomography (CT) scans of children and adolescents. SUMMARY OF BACKGROUND DATA: Spine surgeons increasingly use HU on spine CT as a measure of bone mineral density (BMD). This has not been described in children and adolescents. PATIENTS AND METHODS: Pediatric patients who had a spine CT between 2012 and 2022 were identified. Patients who had more than 1 comorbidity or were syndromic were excluded. Using the bone window, 3 axial images (cephalad, middle, and caudal) of each vertebra were selected. In each axial view, the HU was measured using a "region of interest" (ROI) that included the total cancellous bone area and an ROI excluding the radiolucency present in the posterior vertebral body ("total" vs . "limited"). HU values were compared between total and limited areas and between the axial images at the cephalad, middle, and caudal levels. Each age category data were estimated and stratified. RESULTS: A total of 144 patients (79 females and 65 males) from 2 to 17 years old were included. Mean limited HU was consistently lower than total HU across all images and lumbar levels except for L1. Limited HU taken mid-vertebral body was also consistently lower than those taken cephalad or caudad. Mean limited HU across all ages including all levels was 227 ± 50 (range: 109-357). Stratifying by age showed a gradual decrease in BMD from age 2 to 10 followed by an increase. CONCLUSIONS: This is the first study to measure HU on lumbar CTs in children and adolescents. The technique of measuring BMD in adults should be modified in children by using an ROI that excludes the rarefaction present in the posterior vertebral body. Further studies are needed to evaluate the age-dependent changes in BMD seen in this study.

Performance of the streamlined quality outcomes database web-based calculator: internal and external validation.

BACKGROUND CONTEXT: With an increasing number of web-based calculators designed to provide the probabilities of an individual achieving improvement after lumbar spine surgery, there is a need to determine the accuracy of these models. PURPOSE: To perform an internal and external validation study of the reduced Quality Outcomes Database web-based Calculator (QOD-Calc). STUDY DESIGN: Observational longitudinal cohort. PATIENT SAMPLE: Patients enrolled study-wide in Quality Outcomes Database (QOD) and patients enrolled in DaneSpine at a single institution who had elective lumbar spine surgery with baseline data to complete QOD-Calc and 12-month postoperative data. OUTCOME MEASURES: Oswestry Disability Index (ODI), Numeric Rating Scales (NRS) for back and leg pain, EuroQOL-5D (EQ-5D). METHODS: Baseline data elements were entered into QOD-Calc to determine the probability for each patient having Any Improvement and 30% Improvement in NRS leg pain, back pain, EQ-5D and ODI. These probabilities were compared with the actual 12-month postop data for each of the QOD and DaneSpine cases. Receiver-operating characteristics analyses were performed and calibration plots created to assess model performance. RESULTS: 24,755 QOD cases and 8,105 DaneSpine lumbar cases were included in the analysis. QOD-Calc had acceptable to outstanding ability (AUC: 0.694-0.874) to predict Any Improvement in the QOD cohort and moderate to acceptable ability (AUC: 0.658-0.747) to predict 30% Improvement. QOD-Calc had acceptable to exceptional ability (AUC: 0.669-0.734) to predict Any improvement and moderate to exceptional ability (AUC: 0.619-0.862) to predict 30% Improvement in the DaneSpine cohort. AUCs for the DaneSpine cohort was consistently lower that the AUCs for the QOD validation cohort. CONCLUSION: QOD-Calc performs well in predicting outcomes in a patient population that is similar to the patients that was used to develop it. Although still acceptable, model performance was slightly worse in a distinct population, despite the fact that the sample was more homogenous. Model performance may also be attributed to the low discrimination threshold, with close to 90% of cases reporting Any Improvement in outcome. Prediction models may need to be developed that are highly specific to the characteristics of the population.

Does diabetes affect outcome or reoperation rate after lumbar decompression or arthrodesis? A matched analysis of the Quality Outcomes Database data set.

OBJECTIVE: Diabetes mellitus (DM) is a known risk factor for postsurgical and systemic complications after lumbar spinal surgery. Smaller studies have also demonstrated diminished improvements in patient-reported outcomes (PROs), with increased reoperation and readmission rates after lumbar surgery in patients with DM. The authors aimed to examine longer-term PROs in patients with DM undergoing lumbar decompression and/or arthrodesis for degenerative pathology. METHODS: The Quality Outcomes Database was queried for patients undergoing elective lumbar decompression and/or arthrodesis for degenerative pathology. Patients were grouped into DM and non-DM groups and optimally matched in a 1:1 ratio on 31 baseline variables, including the number of operated levels. Outcomes of interest were readmissions and reoperations at 30 and 90 days after surgery in addition to improvements in Oswestry Disability Index, back pain, and leg pain scores and quality-adjusted life-years at 90 days after surgery. RESULTS: The matched decompression cohort comprised 7836 patients (3236 [41.3] females) with a mean age of 63.5 ± 12.6 years, and the matched arthrodesis cohort comprised 7336 patients (3907 [53.3%] females) with a mean age of 64.8 ± 10.3 years. In patients undergoing lumbar decompression, no significant differences in nonroutine discharge, length of stay (LOS), readmissions, reoperations, and PROs were observed. In patients undergoing lumbar arthrodesis, nonroutine discharge (15.7% vs 13.4%, p < 0.01), LOS (3.2 ± 2.0 vs 3.0 ± 3.5 days, p < 0.01), 30-day (6.5% vs 4.4%, p < 0.01) and 90-day (9.1% vs 7.0%, p < 0.01) readmission rates, and the 90-day reoperation rate (4.3% vs 3.2%, p = 0.01) were all significantly higher in the DM group. For DM patients undergoing lumbar arthrodesis, subgroup analyses demonstrated a significantly higher risk of poor surgical outcomes with the open approach. CONCLUSIONS: Patients with and without DM undergoing lumbar spinal decompression alone have comparable readmission and reoperation rates, while those undergoing arthrodesis procedures have a higher risk of poor surgical outcomes up to 90 days after surgery. Surgeons should target optimal DM control preoperatively, particularly for patients undergoing elective lumbar arthrodesis.

Patient expectations impact patient-reported outcomes and satisfaction after lumbar fusion.

BACKGROUND CONTEXT: Prior studies suggest that patient expectations impact postoperative patient-reported outcomes (PROMs). However, no consensus exists on an appropriate expectations tool. PURPOSE: To examine the impact of patient expectations using a modified version of the Oswestry Disability Index (ODI) on clinical outcomes and patient satisfaction 1 year after lumbar fusion for degenerative pathologies. STUDY DESIGN: Prospective longitudinal cohort. PATIENT SAMPLE: Adults undergoing 1 to 2 level lumbar fusion were identified from four tertiaty spine centers. OUTCOME MEASURES: ODI, EuroQol-5D, Numeric rating scales for back and leg pain. METHODS: Preoperatively, patients completed the ODI, as well as a modified ODI reflecting their expected improvement across the 10 ODI items. For example, item 1 in the ODI asks about Pain Intensity at the moment whereas the Expectations ODI asks "One year after surgery, I expect to have…" The difference between this modified ODI score and the baseline ODI score (Baseine ODI minus Expectations ODI) was defined as the Patient Expectation Score. Patients were stratified into tertiles based on their Expectations score into High (HE), Moderate (ME), and Low (LE) Expectations and compared. RESULTS: There were 30 patients in the HE, 35 in the ME, and 26 in the LE Group, with similar demographics and surgical parameters. Patients in the HE group had worse ODI scores preoperatively (54.96 vs 41.42, p<.001) and were expecting a greater improvement in ODI (43.8 vs 13.5, p<.001). There were fewer patients in the HE group (13, 43%) who reported that they were satisfied with the results compared to either the ME (20, 71%) or LE group (22, 85%, p=.041) despite having similar ODI scores and change in ODI scores 1 year postoperatively. CONCLUSION: An expectations tool, linked to a disease-specific measure may provide the clinician with a practical method of assessing a patient's expectation of results after treatment and aid in the shared decision-making during the preoperative surgical process.

Assessment of the External Validity of Dialogue Support for Predicting Lumbar Spine Surgery Outcomes in a US Cohort.

STUDY DESIGN: External validation using prospectively collected data. OBJECTIVES: To determine the model performance of "Dialogue Support" (DS) in predicting outcomes after lumbar spine surgery. SUMMARY OF BACKGROUND DATA: To help clinicians discuss risk versus benefit with patients considering lumbar fusion surgery, DS has been made available online. As DS was created using a Swedish sample, there is a need to study how well DS performs in alternative populations. PATIENTS AND METHODS: Preoperative data from patients enrolled in the Quality Outcomes Database were entered into DS. The probability for each patient to report satisfaction, achieve success (leg pain improvement ≥3), or have no leg pain 12 months after surgery was extracted and compared with their actual 12-month postoperative data. The ability of DS to identify patients in the Quality Outcomes Database who report satisfaction, achieve success, or have no leg pain 12 months after surgery was determined using Receiver operating characteristic curve analysis, goodness-of-fit tests, and calibration plots. RESULTS: There was a significant improvement in all outcomes in 23,928 cases included in the analysis from baseline to 12 months postoperative. Most (84%) reported satisfaction, 67% achieved success, and 44% were pain-free 12 months postoperative. Receiver operating characteristic analysis showed that DS had a low ability to predict satisfaction [area under the curve (AUC) = 0.606], success (AUC = 0.546), and being pain-free (AUC = 0.578) at 12 months postoperative; poor fit for satisfaction (<0.001) and being pain-free ( P = 0.004), but acceptable fit for success ( P = 0.052). Calibration plots showed underestimation for satisfaction and success, but acceptable estimates for being pain-free. CONCLUSION: DS is not directly transferable to predict satisfaction and success after lumbar surgery in a US population. This may be due to differences in patient characteristics, weights of the variables included, or the exclusion of unknown variables associated with outcomes. Future studies to better understand and improve the transferability of these models are needed.

Opioid-sparing Anesthesia Decreases In-hospital and 1-year Postoperative Opioid Consumption Compared With Traditional Anesthesia: A Propensity-matched Cohort Study.

STUDY DESIGN: Propensity-matched cohort. OBJECTIVE: The aim of this study was to determine if opioid-sparing anesthesia (OSA) reduces in-hospital and 1-year postoperative opioid consumption. SUMMARY OF BACKGROUND DATA: The recent opioid crisis highlights the need to reduce opioid exposure. We developed an OSA protocol for lumbar spinal fusion surgery to mitigate opioid exposure. MATERIALS AND METHODS: Patients undergoing lumbar fusion for degenerative conditions over one to four levels were identified. Patients taking opioids preoperatively were excluded. OSA patients were propensity-matched to non-OSA patients based on age, sex, smoking status, body mass index, American Society of Anesthesiologists grade, and revision versus primary procedure. Standard demographic and surgical data, daily in-hospital opioid consumption, and opioid prescriptions 1 year after surgery were compared. RESULTS: Of 296 OSA patients meeting inclusion criteria, 172 were propensity-matched to non-OSA patients. Demographics were similar between cohorts (OSA: 77 males, mean age=57.69 yr; non-OSA: 67 males, mean age=58.94 yr). OSA patients had lower blood loss (326 mL vs. 399 mL, P =0.014), surgical time (201 vs. 233 min, P <0.001) emergence to extubation time (9.1 vs. 14.2 min, P< 0.001), and recovery room time (119 vs. 140 min, P =0.0.012) compared with non-OSA patients. Fewer OSA patients required nonhome discharge (18 vs. 41, P =0.001) compared with the non-OSA cohort, but no difference in length of stay (90.3 vs. 98.5 h, P =0.204). Daily opioid consumption was lower in the OSA versus the non-OSA cohort from postoperative day 2 (223 vs. 185 morphine milligram equivalents, P =0.017) and maintained each day with lower total consumption (293 vs. 225 morphine milligram equivalents, P =0.003) throughout postoperative day 4. The number of patients with active opioid prescriptions at 1, 3, 6, and 12 months postoperative was statistically fewer in the OSA compared with the non-OSA patients. CONCLUSIONS: OSA for lumbar spinal fusion surgery decreases in-hospital and 1-year postoperative opioid consumption. The minimal use of opioids may also lead to shorter emergence to extubation times, shorter recovery room stays, and fewer discharges to nonhome facilities.

Impact of Educational Background on Preoperative Disease Severity and Postoperative Outcomes Among Patients With Cervical Spondylotic Myelopathy.

STUDY DESIGN: Retrospective review of a prospectively maintained database. OBJECTIVE: Assess differences in preoperative status and postoperative outcomes among patients of different educational backgrounds undergoing surgical management of cervical spondylotic myelopathy (CSM). SUMMARY OF BACKGROUND DATA: Patient education level (EL) has been suggested to correlate with health literacy, disease perception, socioeconomic status (SES), and access to health care. METHODS: The CSM data set of the Quality Outcomes Database (QOD) was queried for patients undergoing surgical management of CSM. EL was grouped as high school or below, graduate-level, and postgraduate level. The association of EL with baseline disease severity (per patient-reported outcome measures), symptoms >3 or ≤3 months, and 24-month patient-reported outcome measures were evaluated. RESULTS: Among 1141 patients with CSM, 509 (44.6%) had an EL of high school or below, 471 (41.3%) had a graduate degree, and 161 (14.1%) had obtained postgraduate education. Lower EL was statistically significantly associated with symptom duration of >3 months (odds ratio=1.68), higher arm pain numeric rating scale (NRS) (coefficient=0.5), and higher neck pain NRS (coefficient=0.79). Patients with postgraduate education had statistically significantly lower Neck Disability Index (NDI) scores (coefficient=-7.17), lower arm pain scores (coefficient=-1), and higher quality-adjusted life-years (QALY) scores (coefficient=0.06). Twenty-four months after surgery, patients of lower EL had higher NDI scores, higher pain NRS scores, and lower QALY scores ( P <0.05 in all analyses). CONCLUSIONS: Among patients undergoing surgical management for CSM, those reporting a lower educational level tended to present with longer symptom duration, more disease-inflicted disability and pain, and lower QALY scores. As such, patients of a lower EL are a potentially vulnerable subpopulation, and their health literacy and access to care should be prioritized.