Nerve root retraction time during lumbar endoscopic discectomy: association with new onset radiculitis, a post-operative neurologic complication.

PURPOSE: To evaluate the relationship between nerve root retraction time, post-operative radiculitis and patient reported outcomes. METHODS: Patients who underwent single- or multi-level lumbar discectomy between 2020 and 2022 for lumbar disk herniations were prospectively followed with pre-operative, interoperative and post-operative variables including radiculitis and patient reported outcomes including VAS, ODI and CAT domains Pain interference, Pain intensity and Physical function. Intraoperative nerve root retraction time was recorded. Paired sample two-tailed t-test and multivariate regression were utilized with p < 0.05 being significant. RESULTS: A total of 157 patients who underwent single- or multi-level endoscopic lumbar discectomy. Average patient age was 44 years, and 64% were male patients. Nerve retraction time ranged from 4 to 15 min. Eighteen percent reported new radiculitis at 2-weeks post-operatively. In patients with new-onset radiculitis 79.2% reported significantly worse VAS leg at 2 weeks post-operative (4.2 vs. 8.3, p < 0.001) compared to 12.5% who had improved VAS leg (9.3 vs. 7, p = 0.1181). Patients with radiculitis and worse VAS scores had substantially longer nerve retraction time (13.8 ± 7.5 min) than patients with improved VAS leg (6.7 ± 1.2 min). At 6 months, patients with longer nerve retraction time had no significant improvement in the ODI or CAT compared to the baseline. CONCLUSIONS: This is the first study in discectomy literature to show that new onset radiculitis and poorer outcomes in VAS leg correlate with longer nerve retraction time at early and later time points.

Predictors of Complication Severity Following Adult Spinal Deformity Surgery: Smoking Rate, Diabetes, and Osteotomy Increase Risk of Severe Adverse Events.

BACKGROUND: Given the physical and economic burden of complications in spine surgery, reducing the prevalence of perioperative adverse events is a primary concern of both patients and health care professionals. This study aims to identify specific perioperative factors predictive of developing varying grades of postoperative complications in adult spinal deformity (ASD) patients, as assessed by the Clavien-Dindo complication classification (Cc) system. METHODS: Surgical ASD patients ≥18 years were identified in the American College of Surgeons' National Surgical Quality Improvement Program from 2005 to 2015. Postoperative complications were stratified by Cc grade severity: minor (I, II, and III) and severe (IV and V). Stepwise regression models generated dataset-specific predictive models for Cc groups. Model internal validation was achieved by bootstrapping and calculating the area under the curve (AUC) of the model. Significance was set at P < 0.05. RESULTS: Included were 3936 patients (59 ± 16 years, 63% women, 29 ± 7 kg/m2) undergoing surgery for ASD (4.4 ± 4.7 levels, 71% posterior approach, 11% anterior, and 18% combined). Overall, 1% of cases were revisions, 39% of procedures involved decompression, 27% osteotomy, and 15% iliac fixation. Additionally, 66% of patients experienced at least 1 complication, 0% of which were Cc grade I, 51% II, 5% III, 43% IV, and 1% V. The final model predicting severe Cc (IV-V) complications yielded an AUC of 75.6% and included male sex, diabetes, increased operative time, central nervous system tumor, osteotomy, cigarette pack-years, anterior decompression, and anterior lumbar interbody fusion. Final models predicting specific Cc grades were created. CONCLUSIONS: Specific predictors of adverse events following ASD-corrective surgery varied for complications of different severities. Multivariate modeling showed smoking rate, osteotomy, diabetes, anterior lumbar interbody fusion, and higher operative time, among other factors, as predictive of severe complications, as classified by the Clavien-Dindo Cc system. These factors can help in the identification of high-risk patients and, consequently, improve preoperative patient counseling. CLINICAL RELEVANCE: The findings of this study provide a foundation for identifying ASD patients at high risk of postoperative complications .

Predicting 30-Day Perioperative Outcomes in Adult Spinal Deformity Patients With Baseline Paralysis or Functional Dependence.

BACKGROUND: Patients undergoing surgical treatment of adult spinal deformity (ASD) are often preoperatively risk stratified using standardized instruments to assess for perioperative complications. Many ASD instruments account for medical comorbidity and radiographic parameters, but few consider a patient's ability to independently accomplish necessary activities of daily living (ADLs). METHODS: Patients ≥18 years undergoing ASD corrective surgery were identified in National Surgical Quality Improvement Program. Patients were grouped by (1) plegic status and (2) dependence in completing ADLs ("totally dependent" = requires total assistance in ADLs, "partially dependent" = uses prosthetics/devices but still requires help, "independent" = requires no help). Quadriplegics and totally dependent patients comprised "severe functional dependence," paraplegics/hemiplegics who are "partially dependent" comprised "moderate functional dependence," and "independent" nonplegics comprised "independent." Analysis of variance with post hoc testing and Kruskal-Wallis tests compared demographics and perioperative outcomes across groups. Logistic regression found predictors of inferior outcomes, controlling for age, sex, body mass index (BMI), and invasiveness. Subanalysis correlated functional dependence with other established metrics such as the modified Frailty Index (mFI) and Charlson Comorbidity Index (CCI). RESULTS: A total of 40,990 ASD patients (mean age 57.1 years, 53% women, mean BMI 29.8 kg/m2) were included. Mean invasiveness score was 6.9 ± 4.0; 95.2% were independent (Indep), 4.3% moderate (Mod), and 0.5% severe (Sev). Sev had higher baseline invasiveness than Mod or Indep groups (9.0, 8.3, and 6.8, respectively, P < 0.001). Compared with the Indep patients, Sev and Mod had significantly longer inpatient length of stay (LOS; 10.9, 8.4, 3.8 days, P < 0.001), higher rates of surgical site infection (2.2%, 2.9%, 1.5%, P < 0.001), and more never events (17.7%, 9.9%, 4.0%, P < 0.001). Mod had higher readmission rates than either the Sev or Indep groups (30.2%, 2.7%, 10.3%, P < 0.001). No differences in implant failure were observed (P > 0.05). Controlling for age, sex, BMI, CCI, invasiveness, and frailty, regression equations showed increasing functional dependence significantly increased odds of never events (OR, 1.82 [95% CI 1.57-2.10], P < 0.001), specifically urinary tract infection (OR, 2.03 [95% CI 1.66-2.50], P < 0.001) and deep venous thrombosis (OR, 2.04 [95% CI 1.61-2.57], P < 0.001). Increasing functional dependence also predicted longer LOS (OR, 3.16 [95% CI 2.85-3.46], P < 0.001) and readmission (OR, 2.73 [95% CI 2.47-3.02], P < 0.001). Subanalysis showed functional dependence correlated more strongly with mFI (r = 0.270, P < 0.001) than modified CCI (mCCI; r = 0.108, P < 0.001), while mFI and mCCI correlated most with one another (r = 0.346, P < 0.001). CONCLUSIONS: Severe functional dependence had significantly longer LOS and more never-event complications than moderate or independent groups. Overall, functional dependence may show superiority to traditional metrics in predicting poor perioperative outcomes, such as increased LOS, readmission rate, and risk of surgical site infection and never events.

A predictive model of perioperative myocardial infarction following elective spine surgery.

Myocardial infarction (MI), and its predictive factors, has been an understudied complication following spine operations. The objective was to assess the risk factors for perioperative MI in elective spine surgery patients as a retrospective case control study. Elective spine surgery patients with a perioperative MI were isolated in the NSQIP. The relationship between MI and non-MI spine patients was assessed using chi-squared and independent samples t-tests. Univariate/multivariate analyses assessed predictive factors of MI. Logistic regression with stepwise model selection was employed to create a model to predict MI occurrence. The study included 196,523 elective spine surgery patients (57.1 yrs, 48%F, 30.4 kg/m2), and 436 patients with acute MI (Spine-MI). Incidence of MI did not change from 2010 to 2016 (0.2%-0.3%, p = 0.298). Spine-MI patients underwent more fusions than patients without MI (73.6% vs 58.4%, p < 0.001), with an average of 1.03 levels fused. Spine-MI patients also had significantly more SPO (5.0% vs 1.8%, p < 0.001) and 3CO (0.9% vs 0.2%, p < 0.001), but less decompression-only procedures (26.4% vs 41.6%, p < 0.001). Spine-MI underwent more revisions (5.3% vs 2.9%, p = 0.003), had greater invasiveness scores (3.41 vs 2.73, p < 0.001) and longer operative times (211.6 vs 147.3 min, p < 0.001). Mortality rate for Spine-MI patients was 4.6% versus 0.05% (p < 0.001). Multivariate modeling for Spine-MI predictors yielded an AUC of 83.7%, and included history of diabetes, cardiac arrest and PVD, past blood transfusion, dialysis-dependence, low preoperative platelet count, superficial SSI and days from operation to discharge. A model with good predictive capacity for MI after spine surgery now exists and can aid in risk-stratification of patients, consequently improving preoperative patient counseling and optimization in the peri-operative period.

Frequency and Implications of Concurrent Complications Following Adult Spinal Deformity Corrective Surgery.

STUDY DESIGN: Retrospective review. OBJECTIVE: Identify co-occurring perioperative complications and associated predictors in a population of patients undergoing surgery for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: Few studies have investigated the development of multiple, co-occurring complications following ASD-corrective surgery. Preoperative risk stratification may benefit from identification of factors associated with multiple, co-occurring complications. METHODS: Elective ASD patients in National Surgical Quality Improvement Program (NSQIP) 2005 to 2016 were isolated; rates of co-occurring complications and affected body systems were assessed via cross tabulation. Random forest analysis identified top patient and surgical factors associated with complication co-occurrence, using conditional inference trees to identify significant cutoff points. Binary logistic regression indicated effect size of top influential factors associated with complication co-occurrence at each factor's respective cutoff point. RESULTS: Included: 6486 ASD patients. The overall perioperative complication rate was 34.8%; 28.5% of patients experienced one complication, 4.5% experienced two, and 1.8% experienced 3+. Overall, 11% of complication co-occurrences were pulmonary/cardiovascular, 9% pulmonary/renal, and 4% integumentary/renal. By complication type, the most common co-occurrences were transfusion/urinary tract infection (UTI) (24.3%) and transfusion/pneumonia (17.7%). Surgical factors of operative time ≥400 minutes and fusion ≥9 levels were the strongest factors associated with the incidence of co-occurring complications, followed by patient-specific variables like American Society of Anesthesiologists (ASA) physical status classification grade ≥2 and age ≥65 years. Regression analysis further showed associations between increasing complication number and longer length of stay (LOS), (R2 = 0.202, P < 0.001), non-home discharge (R2 = 0.111, P = 0.001), and readmission (R2 = 0.010, P < 0.001). CONCLUSION: For surgical ASD patients, the overall rate of co-occurring perioperative complications was 6.3%. Body systems most commonly affected by complication co-occurrences were pulmonary and cardiovascular, and common co-occurrences included transfusion/UTI (24.3%) and transfusion/pneumonia (17.7%). Increasing number of perioperative complications was associated with greater LOS, non-home discharge, and readmission, highlighting the importance of identifying risk factors for complication co-occurrences.Level of Evidence: 3.

Esophagopharyngeal perforation and prevertebral abscess after anterior cervical discectomy and fusion: a case report.

Anterior cervical discectomy and fusion (ACDF) represents one of the most commonly performed spine surgeries. Dysphagia secondary to esophageal injury during retraction is one of the most common complications, and usually leads to self-limiting dysphagia. However, actual perforation and violation of the esophageal tissue is much rarer and can lead to delayed deep infections. Prevertebral abscess' are one of the most feared complications after ACDF, as they can lead to severe tissue swelling, osteomyelitis, hardware failure, and even death. Due to their rarity, a gold standard of workup and treatment is still unknown. A healthy 47-year-old female presents 9 months after a C4-C7 ACDF done at an outside institution with a large prevertebral abscess, osteomyelitis, hardware failure, and pseudoarthrosis secondary to esophagopharyngeal defect and prominent hardware. Overall, the patient underwent eight surgeries, and required an extended course of intravenous (IV) antibiotics, multiple diagnostic procedures, and complex soft tissue coverage using an anterolateral thigh free flap. Currently, the patient is doing well 6 months from her last procedure without any complications or plan for future surgery. This was an extremely rare case of a late occurring prevertebral abscess after ACDF. Dysphagia in the late postoperative setting should be evaluated carefully and thoroughly for any esophageal perforation and deep infection. As exemplified in this case, even partial thickness injuries to the esophageal-pharyngeal anatomy due to hardware irrigation can lead to catastrophic complications over time. Safe removal of all hardware anteriorly to avoid continued irritation of the esophagopharyngeal mucosa should be prioritized. If anterior hardware is necessary for stability, implants with the smallest footprint should be utilized. Early collaboration with ENT colleagues should be a priority and can provide crucial diagnostic and therapeutic interventions. Complex closure with a free flap was shown to be an effective way to provide successful definitive soft tissue coverage.

Same Day Surgical Intervention Dramatically Minimizes Complication Occurrence and Optimizes Perioperative Outcomes for Central Cord Syndrome.

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: The aim of this study was to investigate associations between time to surgical intervention and outcomes for central cord syndrome (CCS) patients. BACKGROUND: As surgery is increasingly recommended for patients with neurological deterioration CCS, it is important to investigate the relationship between time to surgery and outcomes. MATERIALS AND METHODS: CCS patients were isolated in Nationwide Inpatient Sample database 2005-2013. Patients were grouped by time to surgery: same-day, 1-day delay, 2, 3, 4-7, 8-14, and >14 days. Means comparison tests compared patient factors, perioperative complications, and charges across patient groups. Controlling for age, comorbidities, length of stay, and concurrent traumatic fractures, binary logistic regression assessed surgical timing associated with increased odds of perioperative complication, using same-day as reference group. RESULTS: Included: 6734 CSS patients (64% underwent surgery). The most common injury mechanisms were falls (30%) and pedestrian accidents (7%). Of patients that underwent surgery, 52% underwent fusion, 30% discectomy, and 14% other decompression of the spinal canal. Breakdown by time to procedure was: 39% same-day, 16% 1-day, 10% 2 days, 8% 3 days, 16% 4-7 days, 8% 8-14 days, and 3% >14 days. Timing groups did not differ in trauma status at admission, although age varied: [minimum: 1 d (58±15 y), maximum: >14 d (63±13 y)]. Relative to other groups, same-day patients had the lowest hospital charges, highest rates of home discharge, and second lowest postoperative length of stay behind 2-day delay patients. Patients delayed >14 days to surgery had increased odds of perioperative cardiac and infection complications. Timing groups beyond 3 days showed increased odds of VTE and nonhome discharge. CONCLUSIONS: CCS patients undergoing surgery on the same day as admission had lower odds of complication, hospital charges, and higher rates of home discharge than patients that experienced a delay to operation. Patients delayed >14 days to surgery were associated with inferior outcomes, including increased odds of cardiac complication and infection.

Increased cautiousness in adolescent idiopathic scoliosis patients concordant with syringomyelia fails to improve overall patient outcomes.

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is a common cause of spinal deformity in adolescents. AIS can be associated with certain intraspinal anomalies such as syringomyelia (SM). This study assessed the rate o f SM in AIS patients and compared trends in surgical approach and postoperative outcomes in AIS patients with and without SM. METHODS: The database was queried using ICD-9 codes for AIS patients from 2003-2012 (737.1-3, 737.39, 737.8, 737.85, and 756.1) and SM (336.0). The patients were separated into two groups: AIS-SM and AIS-N. Groups were compared using t-tests and Chi-squared tests for categorical and discrete variables, respectively. RESULTS: Totally 77,183 AIS patients were included in the study (15.2 years, 64% F): 821 (1.2%) - AIS-SM (13.7 years, 58% F) and 76,362 - AIS-N (15.2 years, 64% F). The incidence of SM increased from 2003-2012 (0.9 to 1.2%, P = 0.036). AIS-SM had higher comorbidity rates (79 vs. 56%, P < 0.001). Comorbidities were assessed between AIS-SM and AIS-N, demonstrating significantly more neurological and pulmonary in AIS-SM patients. 41.2% of the patients were operative, 48% of AIS-SM, compared to 41.6% AIS-N. AIS-SM had fewer surgeries with fusion (anterior or posterior) and interbody device placement. AIS-SM patients had lower invasiveness scores (2.72 vs. 3.02, P = 0.049) and less LOS (5.0 vs. 6.1 days, P = 0.001). AIS-SM patients underwent more routine discharges (92.7 vs. 90.9%). AIS-SM had more nervous system complications, including hemiplegia and paraplegia, brain compression, hydrocephalous and cerebrovascular complications, all P < 0.001. After controlling for respiratory, renal, cardiovascular, and musculoskeletal comorbidities, invasiveness score remained lower for AIS-SM patients (P < 0.001). CONCLUSIONS: These results indicate that patients concordant with AIS and SM may be treated more cautiously (lower invasiveness score and less fusions) than those without SM.

The Patient-Reported Outcome Measurement Information System (PROMIS) Better Reflects the Impact of Length of Stay and the Occurrence of Complications Within 90 Days Than Legacy Outcome Measures for Lumbar Degenerative Surgery.

BACKGROUND: The Patient-Reported Outcome Measurement Information System (PROMIS) and legacy outcome measures like the Oswestry Disability Index (ODI) have not been compared for their sensitivity in reflecting the impact of perioperative complications and length of stay (LOS) in a surgical thoracolumbar population. The purpose of this study is to assess the strength of PROMIS and ODI scores as they correlate with LOS and complication outcomes of surgical thoracolumbar patients. METHODS: Retrospective cohort study. Included: patients ≥18 years undergoing thoracolumbar surgery with available preoperative and 3-month postoperative ODI and PROMIS scores. Pearson correlation assessed the linear relationships between LOS, complications, and scores for PROMIS (physical function, pain intensity, pain interference) and ODI. Linear regression predicted the relationship between complication incidence and scores for ODI and PROMIS. RESULTS: Included: 182 patients undergoing thoracolumbar surgery. Common diagnoses were stenosis (62.1%), radiculopathy (48.9%), and herniated disc (47.8%). Overall, 58.3% of patients underwent fusion, and 50.0% underwent laminectomy. Patients showed preoperative to postoperative improvement in ODI (50.2 to 39.0), PROMIS physical function (10.9 to 21.4), pain intensity (92.4 to 78.3), and pain interference (58.4 to 49.8, all P < .001). Mean LOS was 2.7 ± 2.8 days; overall complication rate was 16.5%. Complications were most commonly cardiac, neurologic, or urinary (all 2.2%). Whereas preoperative to postoperative changes in ODI did not correlate with LOS, changes in PROMIS pain intensity (r = 0.167, P = .024) and physical function (r = -0.169, P = .023) did. Complications did not correlate with changes in ODI or PROMIS score; however, postoperative scores for physical function (r = -0.205, P = .005) and pain interference (r = 0.182, P = .014) both showed stronger correlations with complication occurrence than ODI (r = 0.143, P = .055). Regression analysis showed postoperative physical function (R 2 = 0.037, P = .005) and pain interference (R 2 = 0.028, P = .014) could predict complications; ODI could not. CONCLUSIONS: PROMIS domains of physical function and pain interference better reflected perioperative complications and LOS than the ODI. These results suggest PROMIS may offer more utility as an outcomes assessment instrument. LEVEL OF EVIDENCE: 3.

Patients with psychiatric diagnoses have increased odds of morbidity and mortality in elective orthopedic surgery.

Psychiatric diagnoses (PD) present a significant burden on elective surgery patients and may have potentially dramatic impacts on outcomes. As ailments of the spine can be particularly debilitating, the effect of PD on outcomes was compared between elective spine surgery patients and other common elective orthopedic surgery procedures. This study included 412,777 elective orthopedic patients who were concurrently diagnosed with PD within the years 2005 to 2016. 30.2% of PD patients experienced a post-operative complication, compared to 25.1% for non-PD patients (p < 0.001). Mood Disorders (bipolar or depressive disorders) were the most commonly diagnosed PD for all elective Orthopedic procedures, followed by anxiety, then dementia (p < 0.001). Logistic regression analysis found PD to be a significant predictor of higher cost to charge ratio (CCR), length of stay (LOS), and death (all p < 0.001). Between, hand, elbow, and shoulder specialties, spine patients had the highest odds of increased CCR and unfavorable discharge, and the second highest odds of death (all p < 0.001).

A cost benefit analysis of increasing surgical technology in lumbar spine fusion.

BACKGROUND CONTEXT: Numerous advances have been made in the field of spine fusion, such as minimally invasive (MIS) or robotic-assisted spine surgery. However, it is unknown how these advances have impacted the cost of care. PURPOSE: Compare the economic outcomes of lumbar spine fusion between open, MIS, and robot-assisted surgery patients. STUDY DESIGN/SETTING: Retrospective review of a single center spine surgery database. PATIENT SAMPLE: Three hundred sixty propensity matched patients. OUTCOME MEASURES: Costs, EuroQol-5D (EQ5D), cost per quality adjusted life years (QALY). METHODS: Inclusion criteria: surgical patients >18 years undergoing lumbar fusion surgery. Patients were categorized into 3 groups based on procedure type: open, MIS, or robotic. Open patients undergoing poster spinal fusion were considered as the control group. MIS patients included those undergoing transforaminal or lateral lumbar interbody fusion with percutaneous screws. Robotic patients were those undergoing robot-assisted fusion. Propensity score matching was performed between all groups for the number of levels fused. Costs were calculated using the PearlDiver database, which reflects both private insurance and Medicare reimbursement claims for ICD-9 codes. For robotic cases, costs were reflective of operational fees and initial purchase cost. Complications and comorbidities and major complications and comorbidities were assessed according to CMS.gov manual definitions. QALYs and cost per QALY were calculated using a 3% discount rate to account for residual decline to life expectancy (78.7 years). Costs per QALY were calculated for both 1 year and life expectancy, assuming no loss of benefit. A 10,000 trial Monte Carlo simulation with probabilistic sensitivity analysis (PSA) assessed our model parameters and costs. RESULTS: Three hundred sixty propensity matched patients (120 open, 120 MIS, 120 robotic) met inclusion criteria. Descriptive statistics for the cohort were: age 58.8±13.5, 50% women, BMI 29.4±6.3, operative time 294.4±119.0, LOS 4.56±3.31 days, estimated blood loss 515.9±670.0 cc, and 2.3±2.2 average levels fused. Rates of post-op complications were significantly higher in robotic cases versus open and MIS (43% vs. 21% and 22% for open and MIS, p<.05). However, revision rates were comparable between all groups (3% open, 3% MIS, 5% robotic, p>.05). After factoring in complications, revisions, and purchasing and operating fees, the costs of robotic cases was significantly higher than both open and MIS surgery ($60,047.01 vs. $42,538.98 open and $41,471.21 MIS). In a subanalysis of 42 patients with baseline (BL) and 1Y EQ5D data, the cost per QALY at 1Y for open, MIS, and robot-assisted cases was $296,624.48, $115,911.69, and $592,734.30. If utility gained was sustained to life expectancy, the cost per QALY was $14,905.75, $5,824.71, $29,785.64 for open, MIS, and robot-assisted cases. Results of the PSA were consistent with MIS surgery having the most incremental cost effectiveness when compared to open and robotic surgery. CONCLUSIONS: Numerous advances have been made in the field of spine surgery, however, there has been limited discussion of the effect these advances have on economic outcomes. When matched for levels fused, robot-assisted surgery patients had significantly higher rates of complications and 30% higher costs of surgery compared to minimally invasive and open spine surgery patients. While 1 year economic outcomes were not optimal for robotic surgery cases, the projected costs per QALYs at life expectancy were well below established acceptable thresholds. The above findings may be reflective of an educational learning curve and emerging surgical technologies undergoing progressive refinement.

A cost utility analysis of treating different adult spinal deformity frailty states.

The aim of this study was to investigate the cost utility of treating non-frail versus frail or severely frail adult spinal deformity (ASD) patients. 79 surgical ASD patients >18 years with available frailty and ODI data at baseline and 2-years post-surgery (2Y) were included. Utility data was calculated using the ODI converted to the SF-6D. QALYs utilized a 3% discount rate to account for decline to life expectancy (LE). Costs were calculated using the PearlDiver database. ICER was compared between non-operative (non-op.) and operative (op.) NF and F/SF patients at 2Y and LE. When compared to non-operative ASD, the ICER was $447,943.96 vs. $313,211.01 for NF and F/SF at 2Y, and $68,311.35 vs. $47,764.61 for NF and F/SF at LE. Frail and severely frail patients had lower cost per QALY compared to not frail patients at 2Y and life expectancy, and had lower ICER values when compared to a non-operative cohort of ASD patients. While these results support operative correction of frail and severely frail patients, it is important to note that these patients are often at worse baseline disability, which is closely related to frailty scores, and have more opportunity to improve postoperatively. Furthermore, there may be a threshold of frailty that is not operable due to the risk of severe complications that is not captured by this analysis. While future research should investigate economic outcomes at extended follow up times, these findings support the cost effectiveness of ASD surgery at all frailty states.

Epidural Steroid Injections for Management of Degenerative Spondylolisthesis: Little Effect on Clinical Outcomes in Operatively and Nonoperatively Treated Patients.

BACKGROUND: Although epidural steroid injection (ESI) may provide pain relief for patients with degenerative spondylolisthesis in treatment regimens of up to 4 months, it remains unclear whether ESI affects crossover from nonoperative to operative management. METHODS: This retrospective cohort study analyzed 2 groups of surgical candidates with degenerative spondylolisthesis: those who received ESI within 3 months after enrollment (ESI group) and those who did not (no-ESI group). Annual outcomes following enrollment were assessed within operative and nonoperative groups (patients who initially chose or were assigned to surgery or nonoperative treatment) by using longitudinal mixed-effect models with a random subject intercept term accounting for correlations between repeated measurements. Treatment comparisons were performed at follow-up intervals. Area-under-the-curve analysis for all time points assessed the global significance of treatment. RESULTS: The study included 192 patients in the no-ESI group and 74 in the ESI group. The no-ESI group had greater baseline Short Form-36 (SF-36) Bodily Pain scores (median, 35 versus 32) and self-reported preference for surgery (38% versus 11%). There were no differences in surgical rates within 4 years after enrollment between the no-ESI and ESI groups (61% versus 62%). The surgical ESI and no-ESI groups also showed no differences in changes in patient-reported outcomes at any follow-up interval or in the 4-year average. Compared with the nonoperative ESI group, the nonoperative no-ESI group showed greater improvements in SF-36 scores for Bodily Pain (p = 0.004) and Physical Function (p = 0.005) at 4 years, Bodily Pain at 1 year (p = 0.002) and 3 years (p = 0.005), and Physical Function at 1 year (p = 0.030) and 2 years (p = 0.002). Of the patients who were initially treated nonsurgically, those who received ESI and those who did not receive ESI did not differ with regard to surgical crossover rates. The rates of crossover to nonoperative treatment by patients who initially chose or were assigned to surgery also did not differ between the ESI and no-ESI groups. CONCLUSIONS: There was no relationship between ESI and improved clinical outcomes over a 4-year study period for patients who chose or were assigned to receive surgery for degenerative spondylolisthesis. In the nonsurgical group, ESI was associated with inferior pain reduction through 3 years, although this was confounded by greater baseline pain. ESI showed little relationship with surgical crossover. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Complication Risk in Primary and Revision Minimally Invasive Lumbar Interbody Fusion: A Comparable Alternative to Conventional Open Techniques?

STUDY DESIGN: Retrospective cohort study of prospective patients undergoing minimally invasive lumbar fusion at a single academic institution. OBJECTIVE: To assess differences in perioperative outcomes between primary and revision MIS (minimally invasive surgical) lumbar interbody fusion patients and compare with those undergoing corresponding open procedures. METHODS: Patients ≥18 years old undergoing lumbar interbody fusion were grouped by surgical technique: MIS or open. Patients within each group were propensity score matched for comorbidities and levels fused. Patient demographics, surgical factors, and perioperative complication incidences were compared between primary and revision cases using means comparison tests, as appropriate. RESULTS: Of the 214 lumbar interbody fusion patients included after propensity score matching, 44 (21%) cases were MIS, and 170 (79%) were open. For MIS patients, there were no significant differences between primary and revision cases in estimated blood loss (EBL; 344 vs 299 cm3, P = .682); however, primary cases had longer operative times (301 vs 246 minutes, P = .029). There were no differences in length of stay (LOS), intensive care unit LOS, readmission, and intraoperative or postoperative complications (all P > .05). For open patients, there were no differences between primary and revision cases in EBL (P > .05), although revisions had longer operative times (331 vs 278 minutes, P = .018) and more postoperative complications (61.7% vs 23.8%, P < .001). MIS revision procedures were shorter than open revisions (182 vs 213 minutes, P = .197) with significantly less EBL (294 vs 965 cm3, P < .001), shorter inpatient and intensive care unit LOS, and fewer postoperative complications (all P < .05). CONCLUSIONS: Clinical outcomes of revision MIS lumbar interbody fusion were similar to those of primary surgery. Additionally, MIS techniques were associated with less EBL, shorter LOS, and fewer perioperative complications than corresponding open revisions.

Readmission in elective spine surgery: Will short stays be beneficial to patients.

There has been limited discussion as to whether spine surgery patients are benefiting from shorter in-patient hospital stays or if they are incurring higher rates of readmission and complications secondary to shortened length of stays. Included in this study were 237,446 spine patients >18yrs and excluding infection. Patients with Clavien Grade 5 complications in 2015 had the lowest mean time to readmission after initial surgery in all years at 12.44 ± 9.03 days. Pearson bivariate correlations between LOS ≤ 1 day and decreasing days to readmission was the strongest in 2016.). Logistic regression analysis found that LOS ≤ 1 day showed an overall increase in the odds of hospital readmission from 2012 to 2016 (2.29 [2.00-2.63], 2.33 [2.08-2.61], 2.35 [2.11-2.61], 2.27 [2.06-2.49], 2.33 [2.14-2.54], all p < 0.001).

ODI Cannot Account for All Variation in PROMIS Scores in Patients With Thoracolumbar Disorders.

STUDY DESIGN: Retrospective review of single institution. OBJECTIVE: To assess the relationship between Patient-Reported Outcomes Measurement Information System (PROMIS) and Oswestry Disability Index (ODI) scores in thoracolumbar patients. METHODS: Included: Patients ≥18 years with a thoracolumbar spine condition (spinal stenosis, disc herniation, low back pain, disc degeneration, spondylolysis). Bivariate correlations assessed the linear relationships between ODI and PROMIS (Physical Function, Pain Intensity, and Pain Interference). Correlation cutoffs assessed patients with high and low correlation between ODI and PROMIS. Linear regression predicted the relationship of ODI to PROMIS. RESULTS: A total of 206 patients (age 53.7 ± 16.6 years, 49.5% female) were included. ODI correlated with PROMIS Physical Function (r = -0.763, P < .001), Pain Interference (r = 0.800, P < .001), and Pain Intensity (r = 0.706, P < .001). ODI strongly predicted PROMIS for Physical Function (R 2 = 0.58, P < .001), Pain Intensity (R 2 = 0.50, P < .001), and Pain Interference (R 2 = 0.64, P < .001); however, there is variability in PROMIS that ODI cannot account for. ODI questions about sitting and sleeping were weakly correlated across the 3 PROMIS domains. Linear regression showed overall ODI score as accounting for 58.3% (R 2 = 0.583) of the variance in PROMIS Physical Function, 63.9% (R 2 = 0.639) of the variance in Pain Interference score, and 49.9% (R 2 = 0.499) of the variance in Pain Intensity score. CONCLUSIONS: There is a large amount of variability with PROMIS that cannot be accounted for with ODI. ODI questions regarding walking, social life, and lifting ability correlate strongly with PROMIS while sitting, standing, and sleeping do not. These results reinforce the utility of PROMIS as a valid assessment for low back disability, while indicating the need for further evaluation of the factors responsible for variation between PROMIS and ODI.

A Simpler, Modified Frailty Index Weighted by Complication Occurrence Correlates to Pain and Disability for Adult Spinal Deformity Patients.

BACKGROUND: The Miller et al adult spinal deformity frailty index (ASD-FI) correlates with complication risk; however, its development was not rooted in clinical outcomes, and the 40 factors needed for its calculation limit the index's clinical utility. The present study aimed to develop a simplified, weighted frailty index for ASD patients METHODS: This study is a retrospective review of a single-center database. Component ASD-FI parameters contributing to overall ASD-FI score were assessed via Pearson correlation. Top significant, clinically relevant factors were regressed against ASD-FI score to generate the modified ASD-FI (mASD-FI). Component mASD-FI factors were regressed against incidence of medical complications, and factor weights were calculated from regression of these coefficients. Total mASD-FI score ranged from 0 to 21, and was calculated by summing weights of expressed parameters. Linear regression and published ASD-FI cutoffs generated corresponding mASD-FI frailty cutoffs: not frail (NF, <7), frail (7-12), severely frail (SF, >12). Analysis of variance assessed the relationship between frailty category and validated baseline measures of pain and disability at baseline. RESULTS: The study included 50 ASD patients. Eight factors were included in the mASD-FI. Overall mean mASD-FI score was 5.7 ± 5.2. Combined, factors comprising the mASD-FI showed a trend of predicting the incidence of medical complications (Nagelkerke R 2 = 0.558; Cox & Snell R 2 = 0.399; P = .065). Breakdown by frailty category is NF (70%), frail (12%), and SF (18%). Increasing frailty category was associated with significant impairments in measures of pain and disability: Oswestry Disability Index (NF: 23.4; frail: 45.0; SF: 49.3; P < .001), SRS-22r (NF: 3.5; frail: 2.6; SF: 2.4; P = .001), Pain Catastrophizing Scale (NF: 41.9; frail: 32.4; SF: 27.6; P < .001), and NRS Leg Pain (NF: 2.3; frail: 7.2; SF: 5.6; P = .001). CONCLUSIONS: This study modifies an existing ASD frailty index and proposes a weighted, shorter mASD-FI. The mASD-FI relies less on patient-reported variables, and it weights component factors by their contribution to adverse outcomes. Because increasing mASD-FI score is associated with inferior clinical measures of pain and disability, the mASD-FI may serve as a valuable tool for preoperative risk assessment.

Obesity negatively affects cost efficiency and outcomes following adult spinal deformity surgery.

BACKGROUND CONTEXT: Obesity has risen to epidemic proportions within the United States. As the rates of obesity have increased, so has its prevalence among patients undergoing adult spinal deformity (ASD) surgery. The effect of obesity on the cost efficiency of corrective procedures for ASD has not been effectively evaluated. PURPOSE: To investigate differences in cost efficiency of ASD surgery for patients stratified by body mass index (BMI). STUDY DESIGN/SETTING: Retrospective review of a single-center ASD database. PATIENT SAMPLE: Five hundred five ASD patients. OUTCOME MEASURES: Complications, revisions, costs, EuroQol-5D (EQ5D), quality-adjusted life years (QALYs), cost per QALY. METHODS: ASD patients (scoliosis≥20°, SVA≥5 cm, PT≥25°, or TK ≥60°) ≥18, undergoing ≥4 level fusions were included. Patients were stratified into NIH-defined obesity groups based on their preoperative BMI: underweight 18.5< (U), normal 18.5 to 24.9 (N), overweight 25.0 to 29.9 (O), obese I 30.0 to 34.9 (OI), obese II 35.0 to 39.9 (OII), and obesity class III 40.0+ (OIII). Total surgery costs for each ASD obesity group were calculated. Costs were calculated using the PearlDiver database, which reflects both private insurance and Medicare reimbursement claims. Overall complications and major complications were assessed according to CMS definitions. QALYs and cost per QALY for obesity groups were calculated using an annual 3% discount up to life expectancy (78.7 years). RESULTS: In all, 505 patients met inclusion criteria. Baseline demographics and surgical details were: age 60.8±14.8, 67.6% female, BMI 28.8±7.30, 81.0% posterior approach, 18% combined approach, 10.1±4.2 levels fused, op time 441.2±146.1 minutes, EBL 1903.8±1594.7 cc, and LOS 8.7±10.7 days. There were 17 U, 154 N patients, 151 O patients, 100 OI, 51 OII, and 32 OIII patients. Revision rates by obesity group were: 0% U, 3% N patients, 3% O patients, 5% OI, 4% OII, and 6% for OIII patients. The total surgery costs by obesity group were: $48,757.86 U, $49,688.52 N, $47,219.93 O, $50,467.66 OI, $51,189.47 OII, and $53,855.79 OIII. In an analysis of patients with baseline and 1 Y EQ5D follow-up, the cost per QALY by obesity group was: $153,737.78 U, $229,222.37 N, $290,361.68 O, $493,588.47 OI, $327,876.21 OII, and $171,680.00 OIII. If that benefit was sustained to life expectancy, the cost per QALY was $8,588.70 U, $12,805.72 N, $16,221.32 O, $27,574.77 OI, $18,317.11 OII, and $9,591.06 for OIII. CONCLUSIONS: Among adult spinal deformity patients, those with BMIs in the obesity I, obesity II, or obesity class III range had more expensive total surgery costs. When assessing 1 year cost per QALY, obese patients had costs 32% higher than nonobese patients ($224,440.61 vs. $331,048.23). Further research is warranted on the utility of optimizing modifiable preoperative health factors for patients undergoing corrective adult spinal deformity surgery.

Diminishing Clinical Returns of Multilevel Minimally Invasive Lumbar Interbody Fusion.

STUDY DESIGN: Single institution retrospective clinical review. OBJECTIVE: To investigate the relationship between levels fused and clinical outcomes in patients undergoing open and minimally invasive surgical (MIS) lumbar fusion. SUMMARY OF BACKGROUND DATA: Minimally invasive spinal fusion aims to reduce the morbidity associated with conventional open surgery. As multilevel arthrodesis procedures are increasingly performed using MIS techniques, it is necessary to weigh the risks and benefits of multilevel MIS lumbar fusion as a function of fusion length. METHODS: Patients undergoing <4 level lumbar interbody fusion were stratified by surgical technique (MIS or open), and grouped by fusion length: 1-level, 2-levels, 3+ levels. Demographics, Charlson Comorbidity Index (CCI), surgical factors, and perioperative complication rates were compared between technique groups at different fusion lengths using means comparison tests. RESULTS: Included: 361 patients undergoing lumbar interbody fusion (88% transforaminal, 14% lateral; 41% MIS). Breakdown by fusion length: 63% 1-level, 22% 2-level, 15% 3+ level. Op-time did not differ between groups at 1-level (MIS: 233 min vs. Open: 227, P = 0.554), though MIS at 2-levels (332 min vs. 281) and 3+ levels (373 min vs. 323) were longer (P = 0.033 and P = 0.231, respectively). While complication rates were lower for MIS at 1-level (15% vs. 30%, P = 0.006) and 2-levels (13% vs. 27%, P = 0.147), at 3+ levels, complication rates were comparable (38% vs. 35%, P = 0.870). 3+ level MIS fusions had higher rates of ileus (13% vs. 0%, P = 0.008) and a trend of increased adverse pulmonary events (25% vs. 7%, P = 0.110). MIS was associated with less EBL at all lengths (all P < 0.01) and lower rates of anemia at 1-level (5% vs. 18%, P < 0.001) and 2-levels (7% vs. 16%, P = 0.193). At 3+ levels, however, anemia rates were similar between groups (13% vs. 15%, P = 0.877). CONCLUSION: MIS lumbar interbody fusions provided diminishing clinical returns for multilevel procedures. While MIS patients had lower rates of perioperative complications for 1- and 2-level fusions, 3+ level MIS fusions had comparable complication rates to open cases, and higher rates of adverse pulmonary and ileus events. LEVEL OF EVIDENCE: 3.