Outcomes and complications of diabetes mellitus on patients undergoing degenerative lumbar spine surgery

Clinicosocial determinants of hospital stay following cervical decompression: A public healthcare perspective and machine learning model

OBJECTIVE

Post-operative length of hospital stay (LOS) is a valuable measure for monitoring quality of care provision, patient recovery, and guiding hospital resource management. But the impact of patient ethnicity, socio-economic deprivation as measured by the indices of multiple deprivation (IMD), and pre-existing health conditions on LOS post-anterior cervical decompression and fusion (ACDF) is under-researched in public healthcare settings.

METHODS

From 2013 to 2023, a retrospective study at a single center reviewed all ACDF procedures. We analyzed 14 non-clinical predictors-including demographics, comorbidities, and socio-economic status-to forecast a categorized LOS: short (≤2 days), medium (2-3 days), or long (>3 days). Three machine learning (ML) models were developed and assessed for their prediction reliability.

RESULTS

2033 ACDF patients were analyzed; 79.44 % had a LOS ≤ 2 days. Significant predictors of LOS included patient sex (HR:0.81[0.74-0.88], p < 0.005), IMD decile (HR:1.38[1.24-1.53], p < 0.005), smoking (HR:1.24[1.12-1.38], p < 0.005), DM (HR:0.70[0.59-0.84], p < 0.005), and COPD (HR:0.66, p = 0.01). Asian patients had the highest mean LOS (p = 0.003). Testing on 407 patients, the XGBoost model achieved 80.95 % accuracy, 71.52 % sensitivity, 85.76 % specificity, 71.52 % positive predictive value, and a micro F1 score of 0.715. This model is available at: https://acdflos.streamlit.app.

CONCLUSIONS

Utilizing non-clinical pre-operative parameters such as patient ethnicity, socio-economic deprivation index, and baseline comorbidities, our ML model effectively predicts postoperative LOS for patient undergoing ACDF surgeries. Yet, as the healthcare landscape evolves, such tools will require further refinement to integrate peri and post-operative variables, ensuring a holistic decision support tool.

Factors associated with improvement in tibialis anterior weakness due to lumbar degenerative disease

BACKGROUND

The weakness of the tibialis anterior remains to be a controversial topic. There has been no study that used electrophysiological assessment of the function of the lumbar and sacral peripheral motor nerves. The aim is to evaluate surgical outcomes in patients with weakness of the tibialis anterior using neurological and electrophysiological assessments.

METHODS

We enrolled 53 patients. Tibialis anterior weakness was quantified by muscle strength, as assessed using a manual muscle test on a scale of 1 through 5, with scores <5 indicating weakness. Postoperative improvement in muscle strength was classified as excellent (5 grades recovered), good (more than one grade recovered), or fair (less than one grade recovered).

RESULTS

Surgical outcomes for tibialis anterior function were categorized as "excellent" in 31, "good" in 8, "fair" in 14 patients. Significant difference in outcomes were observed depending on diabetes mellitus status, type of surgery, and the compound muscle action potentials amplitudes of the abductor hallucis and extensor digitorum brevis (p < 0.05). Surgical outcomes were classified into two groups, patients with excellent and good outcomes (Group 1) and patients with fair outcome (Group 2). Using the forward selection stepwise method, sex and the compound muscle action potentials amplitudes of the extensor digitorum brevis were identified as significant factors for their positive association with Group 1 status. The diagnostic power of the predicted probability was as high as 0.87 in terms of area under curve of the receiver operating characteristic curve.

CONCLUSIONS

There was a significant correlation between the prognosis of tibialis anterior weakness and sex and the compound muscle action potentials amplitude of extensor digitorum brevis, suggesting that recording the compound muscle action potentials amplitude of extensor digitorum brevis will aid the outcome assessment of future surgical interventions for tibialis anterior weakness.

The Predictive Potential of Nutritional and Metabolic Burden: Development of a Novel Validated Metric Predicting Increased Postoperative Complications in Adult Spinal Deformity Surgery

STUDY DESIGN

A retrospective cohort review.

OBJECTIVE

To develop a scoring system for predicting increased risk of postoperative complications in adult spinal deformity (ASD) surgery based on baseline nutritional and metabolic factors.

BACKGROUND

Endocrine and metabolic conditions have been shown to adversely influence patient outcomes and may increase the likelihood of postoperative complications. The impact of these conditions has not been effectively evaluated in patients undergoing ASD surgery.

MATERIALS AND METHODS

ASD patients 18 years or above with baseline and two-year data were included. An internally cross-validated weighted equation using preoperative laboratory and comorbidity data correlating to increased perioperative complications was developed via Poisson regression. Body mass index (BMI) categorization (normal, over/underweight, and obese) and diabetes classification (normal, prediabetic, and diabetic) were used per the Centers for Disease Control and Prevention and the American Diabetes Associates parameters. A novel ASD-specific nutritional and metabolic burden score (ASD-NMBS) was calculated via Beta-Sullivan adjustment, and Conditional Inference Tree determined the score threshold for experiencing ≥1 complication. Cohorts were stratified into low-risk and high-risk groups for comparison. Logistic regression assessed correlations between increasing burden score and complications.

RESULTS

Two hundred one ASD patients were included (mean age: 58.60±15.4, sex: 48% female, BMI: 29.95±14.31, Charlson Comorbidity Index: 3.75±2.40). Significant factors were determined to be age (+1/yr), hypertension (+18), peripheral vascular disease (+37), smoking status (+21), anemia (+1), VitD hydroxyl (+1/ng/mL), BMI (+13/cat), and diabetes (+4/cat) (model: P <0.001, area under the curve: 92.9%). Conditional Inference Tree determined scores above 175 correlated with ≥1 post-op complication ( P <0.001). Furthermore, HIGH patients reported higher rates of postoperative cardiac complications ( P =0.045) and were more likely to require reoperation ( P =0.024) compared with low patients.

CONCLUSIONS

The development of a validated novel nutritional and metabolic burden score (ASD-NMBS) demonstrated that patients with higher scores are at greater risk of increased postoperative complications and course. As such, surgeons should consider the reduction of nutritional and metabolic burden preoperatively to enhance outcomes and reduce complications in ASD patients.

The Effect of Diabetes on Complications after Spinal Fusion: A Systematic Review and Meta-Analysis

OBJECTIVE

Spinal fusion procedures are used to treat a wide variety of spinal pathologies. Diabetes mellitus (DM) has been shown to be a significant risk factor for several complications following these procedures in previous studies. To the authors' knowledge, this is the first systematic review and meta-analysis elucidating the relationship between DM and complications occurring after spinal fusion procedures.

METHODS

Systematic literature searches of PubMed and EMBASE were performed from their inception to October 1, 2022, to identify studies that directly compared postfusion complications in patients with and without DM. Studies met the prespecified inclusion criteria if they reported the following data for patients with and without DM: (1) demographics; (2) postspinal fusion complication rates; and (3) postoperative clinical outcomes. The included studies were then pooled and analyzed.

RESULTS

Twenty-eight studies, with a cumulative total of 18,853 patients (2695 diabetic patients), were identified that met the inclusion criteria. Analysis showed that diabetic patients had significantly higher rates of total number of postoperative complications (odds ratio [OR] = 1.33; 95% confidence interval [CI] = 1.12-1.58; P = 0.001), postoperative pulmonary complications (OR=2.01; 95%CI=1.31-3.08; P = 0.001), postoperative renal complications (OR=2.20; 95%CI=1.27-3.80; P = 0.005), surgical site infection (OR=2.65; 95%CI=2.19-3.20; P < 0.001), and prolonged hospital stay (OR=1.67; 95%CI=1.47-1.90; P < 0.001).

CONCLUSIONS

Patients with DM had a significantly higher risk of developing complications after spinal fusion, particularly pulmonary and renal complications, in addition to surgical site infections and had a longer length of stay. These findings are important for informed discussions of surgical risks with patients and families before surgery.

Postoperative Length of Stay in Patients With Stress Hyperglycemia Compared to Patients With Diabetic Hyperglycemia: A Retrospective Cohort Study

BACKGROUND

Postoperative hospital length of stay (LOS) is longer in patients with diabetes than in patients without diabetes. Stress hyperglycemia (SH) in patients without a history of diabetes has been associated with adverse postoperative outcomes. The effect of SH on postoperative LOS is uncertain. The aim of this study is to compare postoperative LOS in patients with SH to patients with diabetic hyperglycemia (DH) following noncardiac surgery.

METHODS

We carried out a retrospective cohort study of inpatients with at least two glucose measurements ≥180 mg/dL. Two groups were compared. Patients with SH had no preoperative history of diabetes. Patients were considered to have DH if they had an established preoperative diagnosis of diabetes mellitus or a preoperative hemoglobin A1c (HbA1c) ≥6.5%. The primary outcome measure was hospital LOS.

RESULTS

We included 270 patients with postoperative hyperglycemia-82 in the SH group and 188 in the DH group. In a linear regression analysis, hospital LOS was longer in the SH group than in the DH group (10.4 vs 7.3 days; P = .03). Within the SH group, we found no association between LOS and prompt treatment of hyperglycemia within 12 hours (P = .43), insulin dose per day (P = .89), or overall mean glucose (P = .13).

CONCLUSIONS

Postoperative LOS was even longer in patients with SH than in patients with DH, representing a potential target for quality improvement efforts. We did not, however, find evidence that improved treatment of SH was associated with reduction in LOS.

Factors associated with the time required for CRP normalization in pyogenic spondylitis: A retrospective observational study

Background

Treatment for pyogenic spondylitis tends to be prolonged; however, few studies have examined the factors associated with the time required for infection control. Therefore, we analyzed a consecutive cohort of patients to identify factors associated with the time required to control infection in pyogenic spondylitis. This study aimed to clarify the factors linked to the duration necessary for achieving infection control in cases of pyogenic spondylitis, using C-reactive protein (CRP) normalization as an indicator.

Methods

In this retrospective observational study, we investigated 108 patients diagnosed with pyogenic spondylitis. We evaluated the number of days from the first visit to CRP normalization; for cases wherein CRP did not normalize, the number of days to the date of final blood sampling was evaluated. In the present study, infection control in pyogenic spondylitis was defined as a CRP falling within the normal range (≤0.14 mg/dL). We performed univariate and multivariate Cox regression analyses to identify various factors associated with the time required for CRP normalization in pyogenic spondylitis.

Results

The mean time required for CRP normalization was 148 days. Univariate Cox regression analysis showed that the serum creatinine level, estimated glomerular filtration rate (eGFR), lymphocyte percentage, neutrophil percentage, CRP level, CRP-albumin ratio, and neutrophil-to-lymphocyte ratio were significantly associated with the time required to control infection. Multivariate Cox regression analysis showed that a higher neutrophil percentage, diabetes mellitus, and a lower eGFR were the independent factors associated with a longer infection control time.

Conclusions

We found that a higher neutrophil percentage, diabetes mellitus, and a lower eGFR were significantly associated with a longer time for CRP normalization in pyogenic spondylitis. These findings may help identify patients with pyogenic spondylitis who are at a high risk for an extended infection control period.

The effect of diabetes mellitus on lumbar disc degeneration: an MRI-based study

PURPOSE

This study aims to analyse the effect of diabetes mellitus (DM) on the radiological changes of Magnetic Resonance Imaging (MRI) on the intervertebral discs and paravertebral muscle to investigate the effect of DM on spinal degeneration.

METHODS

This retrospective study initially included 262 patients who underwent treatment between January 2020 and December 2021 because of lumbar disc herniation. Amongst these patients, 98 patients suffered from type 2 diabetes mellitus (T2DM) for more than five years; this is the poorly controlled group (haemoglobin A1c (HbA1c) ≥ 6.5%; BMI: 26.28 ± 3.60; HbA1c: 7.5, IQR = 1.3). Another 164 patients without T2DM are included in the control group. The data collected and analysed include gender, age, smoking, alcohol use, disease course, Charlson Comorbidity Index, BMI, and radiological parameters including disc height, modified Pfirrmann grading scores, percentage of fat infiltration area of paravertebral muscle, and pathological changes of the endplate.

RESULTS

After propensity score-matched analysis, the difference in general data between the control and T2DM groups was eliminated, and 186 patients were analysed. The modified Pfirrmann grading scores showed statistical differences in every lumbar segment, suggesting that the T2DM group suffered from greater disc degeneration at all L1-S1 segments compared with the control group. The disc height from L1/2 to L5/S1 was not statistically different between the two groups. Compared to the T2DM group, the control group had a lower percentage of fat infiltration areas in L4/5 and L5/S1 paravertebral muscle, whereas L1/2 to L3/4 showed no statistical difference. The T2DM group had more pathological changes of cartilage endplate compared with the control group.

CONCLUSIONS

Prolonged uncontrolled hyperglycaemia may contribute to lumbar disc degeneration, fatty infiltration of the paraspinal muscles in the lower lumbar segments, and increased incidence of endplate cartilage pathological changes in patients with degenerative disc disease.

Risk factors for prolonged length of stay after first single-level lumbar microdiscectomy

OBJECTIVE

The objective is to identify risk factors that potentially prolong the hospital stay in patients after undergoing first single-level open lumbar microdiscectomy.

METHODS

A retrospective single-centre study was conducted. Demographic data, medical records, intraoperative course, and imaging studies were analysed. The outcome measure was defined by the number of days stayed after the operation. A prolonged length of stay (LOS) stay was defined as a minimum of one additional day beyond the median hospital stay in our patient collective. Bivariate analysis and multiple stepwise regression were used to identify independent factors related to the prolonged hospital stay.

RESULTS

Two hundred consecutive patients who underwent first lumbar microdiscectomy between 2018 and 2022 at our clinic were included in this study. Statistical analysis of factors potentially prolonging postoperative hospital stay was done for a total of 24 factors, seven of them were significantly related to prolonged LOS in bivariate analysis. Sex (p = 0.002, median 5 vs. 4 days for females vs. males) and age (rs = 0.35, p ≤ 0.001, N = 200) were identified among the examined demographic factors. Regarding preoperative physical status, preoperative immobility reached statistical significance (p ≤ 0.001, median 5 vs. 4 days). Diabetes mellitus (p = 0.043, median 5 vs. 4 days), anticoagulation and/or antiplatelet agents (p = 0.045, median 5 vs. 4 days), and postoperative narcotic consumption (p ≤ 0.001, median 5 vs. 4 days) as comorbidities were associated with a prolonged hospital stay. Performance of nucleotomy (p = 0.023, median 5 vs. 4 days) was a significant intraoperative factor. After linear stepwise multivariable regression, only preoperative immobility (p ≤ 0.001) was identified as independent risk factors for prolonged length of postoperative hospital stay.

CONCLUSION

Our study identified preoperative immobility as a significant predictor of prolonged hospital stay, highlighting its value in preoperative assessments and as a tool to pinpoint at-risk patients. Prospective clinical trials with detailed assessment of mobility, including grading, need to be done to verify our results.

Diabetes in Orthopaedic Sports Medicine Surgeries Standard Review

Diabetes mellitus has been shown to affect the outcomes of various orthopaedic procedures. Although orthopaedic sports medicine procedures tend to be less invasive and are often performed on younger and healthier patients, diabetes is associated with an increased risk of postoperative infection, readmission, and lower functional outcome scores. However, this risk may be moderated by the glycemic control of the individual patient, and patients with a low perioperative hemoglobin A1c may not confer additional risk. Further research is needed to evaluate the impact of diabetes on surgical outcomes in sports orthopaedics is needed, with the goal of evaluating mediating factors such as glycemic control in mind.

The Effects of Blood Glucose Control in the Operative Spine Patient: A Systematic Review

OBJECTIVE

To our knowledge, this is the first systematic review to evaluate the available literature on the effects of perioperative serum glucose (SG) on outcomes for patients undergoing spine surgery. This review will add insight into how the perioperative management of SG affects the outcomes of patients undergoing spine surgery.

METHODS

Three databases were used in this review including Embase, PubMed, and Cochrane Library. The searches were from 2012 to 2022 and included the terms "spine surgery" and "glucose level" to identify studies that demonstrated a correlation between glucose level and postoperative outcomes. Pediatric studies, those that did not specify spine surgical outcomes related to glucose levels, and non-English studies were excluded. The methodological items for nonrandomized studies score was used to assess risk of bias in the included studies.

RESULTS

This review included a total of 9 cohort studies, both prospective and retrospective, encompassing a total of 431,156 subjects. Seven of the 9 studies reported an increased overall complication rate among patients with diabetes or with higher SG levels, and 4 studies demonstrated an increased infection rate among this population. Two studies reported an association between decreased SG levels and improved neurological recovery when a deficit was present preoperatively, and 1 of the studies found that this association was statistically significant.

LIMITATIONS

Limitations of this review include lack of standardization regarding type of surgery, location of the spine, and level of evidence.

CONCLUSION

Most of the current literature suggests that elevated SG levels in patients undergoing spine surgery likely leads to higher complication rates and may lead to increased infection rates, and this review reinforced the current evidence. Additionally, perioperative SG levels may be associated with the extent of neurological recovery after surgery, but further investigation may be warranted.

CLINICAL RELEVANCE

This review adds to the current body of evidence regarding perioperative SG levels and its association with complications.

LEVEL OF EVIDENCE: 2

Anesthesia practice among joint arthroplasty patients with a previous lumbar spine surgery

STUDY OBJECTIVE

To analyze the use of neuraxial techniques in total hip or knee arthroplasty patients who previously underwent lumbar spine surgeries.

DESIGN

Retrospective analysis of a national database.

SETTING

U.S. hospitals.

PATIENTS

Patients undergoing a total hip or knee arthroplasty, stratified by those with a previous lumbar fusion or decompression procedure.

MEASUREMENTS

Our primary outcome was the use of neuraxial anesthesia; secondary outcomes included combined complications, cardio-pulmonary complications, and prolonged length of stay. Patients with and without a history of a lumbar procedure were compared using mixed-effects regression.

MAIN RESULTS

Among 758,857 THAs 8961 had a history of lumbar fusion and 8599 of decompression. Among 1,387,335 TKAs 15,827 had a history of lumbar fusion and 13,652 of decompression. History of a lumbar fusion was associated with lower odds of neuraxial anesthesia use in THA (OR: 0.74 CI: 0.70-0.79, p ≤0.0001) and TKA (OR: 0.80 CI: 0.77-0.84, p ≤0.0001).

CONCLUSIONS

Previous lumbar fusion -but not decompression- surgery is associated with lower neuraxial anesthesia in THA/TKA patients, despite its use being universally associated with decreased length of stay. More research is needed to address the importance of neuraxial techniques in patients with prior spine surgery.

Strategies for Perioperative Optimization in Upper Extremity Fracture Care

Perioperative optimization in upper extremity fracture care must balance the need for timely treatment with the benefits of medical optimization. Care pathways directed at optimizing glycemic control, chronic anticoagulation, smoking history, nutrition, and frailty can reduce surgical risk in upper extremity fracture care. The development of multidisciplinary approaches that tie risk modification with risk stratification is needed.

Risk factors for venous thromboembolism following surgical treatment of fractures: A systematic review and meta-analysis

This study aimed to determine the risk factors for postoperative venous thromboembolism (VTE) in patients treated surgically for fractures using a meta-analytic approach. Electronic searches were performed in PubMed, Embase, and the Cochrane library from inception until February 2022. The odds ratio (OR) and 95% confidence interval (CI) were applied to calculate the pooled effect estimate using the random-effects model. Sensitivity, subgroup, and publication bias tests were also performed. Forty-four studies involving 3 239 291 patients and reporting 11 768 VTE cases were selected for the meta-analysis. We found that elderly (OR: 1.72; 95% CI: 1.38-2.15; P < .001), American Society of Anesthesiologists (ASA) ≥ 3 (OR: 1.82; 95% CI: 1.46-2.29; P < .001), blood transfusion (OR: 1.82; 95% CI: 1.14-2.92; P = .013), cardiovascular disease (CVD) (OR: 1.40; 95% CI: 1.22-1.61; P < .001), elevated D-dimer (OR: 4.55; 95% CI: 2.08-9.98; P < .001), diabetes mellitus (DM) (OR: 1.36; 95% CI: 1.19-1.54; P < .001), hypertension (OR: 1.31; 95% CI: 1.09-1.56; P = .003), immobility (OR: 3.45; 95% CI: 2.23-5.32; P < .001), lung disease (LD) (OR: 2.40; 95% CI: 1.29-4.47; P = .006), obesity (OR: 1.52; 95% CI: 1.27-1.82; P < .001), peripheral artery disease (PAD) (OR: 2.13; 95% CI: 1.21-3.73; P = .008), prior thromboembolic event (PTE) (OR: 5.17; 95% CI: 3.14-8.50; P < .001), and steroid use (OR: 2.37; 95% CI: 1.73-3.24; P < .001) were associated with an increased risk of VTE. Additionally, regional anaesthesia (OR: 0.66; 95% CI: 0.45-0.96; P = .029) was associated with a reduced risk of VTE following surgical treatment of fractures. However, alcohol intake, cancer, current smoking, deep surgical site infection, fusion surgery, heart failure, hypercholesterolemia, liver and kidney disease, sex, open fracture, operative time, preoperative anticoagulant use, rheumatoid arthritis, and stroke were not associated with the risk of VTE. Post-surgical risk factors for VTE include elderly, ASA ≥ 3, blood transfusion, CVD, elevated D-dimer, DM, hypertension, immobility, LD, obesity, PAD, PTE, and steroid use.

Patient-level payment patterns prior to single level lumbar decompression are associated with resource utilization, postoperative payments, and adverse events

BACKGROUND

Understanding patient-specific trends in costs and healthcare resource utilization (HCRU) surrounding lumbar spine surgery is critically needed to better inform surgical decision making and the development of targeted interventions.

PURPOSE

1) Identify subgroups of patients following distinct patterns in direct healthcare payments pre- and postoperatively, 2) determine whether these patterns are associated with patient and surgical factors, and 3) examine whether preoperative payment patterns are related to postoperative payments, healthcare resource utilization (HCRU), and adverse events.

STUDY DESIGN/SETTING

Retrospective analysis of an administrative claims database (IBM Marketscan Research Databases 2007-2015).

PATIENT SAMPLE

Adults undergoing primary single-level decompression surgery for lumbar stenosis (n=12,394).

OUTCOME MEASURES

Direct healthcare payments, HCRU payments (15 categories), 90-day complications and all-cause readmission, 2-year reoperation METHODS: Group-based trajectory modeling is an application of finite mixture modeling that is able to identify meaningful subgroups within a population that follow distinct developmental trajectories over time. We used this technique to identify subgroups of patients following distinct profiles in preoperative direct healthcare payments. A separate analysis was performed to identify distinct profiles in payments postoperatively. Patient and surgical factors associated with these payment profiles were assessed with multinomial logistic regression, and associations with adverse events were assessed with risk-adjusted multivariable logistic regression.

RESULTS

We identified 4 preoperative patient payment subgroups following distinct profiles in payments: Pre-Low (5.8% of patients), Pre-Early-Rising (4.8%), Pre-Medium (26.1%), and Pre-High (63.3%). Postoperatively, 3 patient subgroups were identified: Post-Low (8.9%), Post-Medium (29.6%), and Post-High (61.4%). Patients following the higher-cost pre- and postoperative payment profiles were older, more likely female, and had a greater physical and mental comorbidity burden. With each successively higher preoperative payment profile, patients were increasingly likely to have high postoperative payments, use more HCRU (particularly high-cost services such as inpatient admissions, ER, and SNF/IRF care), and experience postoperative adverse events. Following risk adjustment for patient and surgical factors, patients following the Pre-High payment profile had 209.5 (95% CI: 144.2, 309.7; p<.001) fold greater odds for following the Post-High payment profile, 1.8 (1.3, 2.5; p=.003) fold greater odds for 90-day complications, and 1.7 (1.2, 2.6; p=.035) fold greater odds for 2-year reoperation relative to patients following the Pre-Low payment profile.

CONCLUSIONS

There are identifiable subgroups of patients who follow distinct profiles in direct healthcare payments surrounding lumbar decompression surgery. These payment profiles are related to patient age, sex, and physical and mental comorbidities. Notably, preoperative payment profiles may provide prognostic value, as they are associated with postoperative costs, HCRU, and adverse events.

LEVEL OF EVIDENCE

III.

Vitamin D deficiency during the perioperative period increases the rate of hardware failure and the need for revision fusion in adult patients undergoing single-level lumbar spine instrumentation surgery

Background

Vitamin D has been shown to play important roles in both calcium homeostasis and bone healing. Only three studies have directly examined the relationship between vitamin D deficiency and hardware failure, nonunion, and/or revision surgery. Results are contradictory and none were large enough to provide the statistical power necessary to make definitive conclusions.

Methods

A retrospective analysis was performed utilizing the PearlDiver national insurance claims database consisting of 91 million individual patient records. Patients aged 30 and over who underwent a non-segmental posterior lumbar fusion procedure (CPT-22840) in 2012-2019 were included. Data collected included, hardware failure, revision surgery occurrence, and vitamin D deficiency. Hardware failure and revision rates were compared between vitamin D deficient and non-deficient groups. We ran a logistic regression analysis using the following variables: age, Charlson Comorbidity Index (CCI), gender, vitamin D deficiency, obesity, tobacco use, diabetes, osteoporosis, rheumatoid arthritis, and Crohn's disease.

Results

108,137 patients matching inclusion criteria were identified, with an overall hardware failure rate of 2.7% and revision rate of 4.1%. Failure rates were significantly higher for patients diagnosed with vitamin D deficiency during the full queried period (3.3% vs. 2.6%, OR = 1.26; p < 0.0001), as were revision rates (4.3% vs 3.5%, OR = 1.25; p < 0.0001). Patients diagnosed with deficiency pre-surgery, higher failure (3.1% vs 2.6%, OR = 1.19; p < 0.01) and rates of revision (4.4% vs 3.5%, OR = 1.27; p < 0.0001) were increased compared to the non-deficient group. In the logistic regression analysis, vitamin D deficiency remains a significant contributor to hardware failure and revision surgery.

Conclusions

These results demonstrate that pre- and/or post-operative vitamin D deficiency is independently correlated with risk for hardware failure and revision surgery in single-level lumbar fusion patients.

Nutritional Optimization for Post-Spinal Surgery Recovery

Adequate nutritional intake is a key component of uncomplicated recovery from spinal surgery. Though much in the literature exists regarding its importance, specific dietary regimens for spinal surgery remain understudied, and little is available in compiling both preoperative and postoperative nutritional recommendations for patients. The complexity that may exist with these recommendations -- especially in the context of patients with diabetes or those who use substances -- has led in recent years to the development of protocols such as Enhanced Recovery After Surgery (ERAS), which gives providers a guideline upon which to base their nutritional counselling. More innovative regimens, such as the use of bioelectrical impedance analyses to assess nutritional status, have also emerged, resulting in a vast array of dietary recommendations and protocols for spinal surgery. In the following paper, we aim to compile a few of these guidelines, comparing various preoperative and postoperative nutritional strategies as well as making note of special considerations, like patients with diabetes or those who use substances. We also work to overview several such dietary "protocols" available in the literature, with a special focus on ERAS and more recent regimens like the Northwestern High-Risk Spine Protocol. We briefly mentioned preclinical work on novel nutritional recommendations as well. Ultimately, we hope to highlight the importance of nutrition in spinal surgery and address the need for greater cohesion of dietary strategies already in existence.

The Effect of Diabetes and Metabolic Syndrome on Spine Surgery Outcomes

PURPOSE OF REVIEW

Diabetes and metabolic syndrome are highly prevalent in patients undergoing spine surgery. This review aims to capture both the findings of recently published literature investigating the effects of diabetes and metabolic syndrome on spine surgery outcomes and the current best practices in patient management.

RECENT FINDINGS

Diabetes and metabolic syndrome both contribute to worse outcomes in patients undergoing spine surgery. Although patients with diabetes are at greater risk of complications, those with uncontrolled diabetes experience increased healthcare costs and greater odds of postoperative complications. Furthermore, metabolic syndrome is repeatedly shown to have an adverse effect on spine surgery outcomes, including healthcare costs and medical complications. Spine surgeons should coordinate care with primary care physicians to optimize the preoperative profile of patients with comorbidities like diabetes and metabolic syndrome to minimize operative risk. With the shift to value-based care, understanding the patient factors that lead to complications is becoming increasingly important. Future studies should build upon the current literature and design preoperative interventions for at-risk patients. Additionally, further research is needed to analyze the modulatory effects of the social determinants of health in patients with diabetes and metabolic syndrome.

Frailty and Sarcopenia: Impact on Outcomes Following Elective Degenerative Lumbar Spine Surgery

STUDY DESIGN

This is a retrospective review of prospectively collected data.

OBJECTIVE

The aim was to evaluate the impact of frailty and sarcopenia on outcomes after lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

Elderly patients are commonly diagnosed with degenerative spine disease requiring surgical intervention. Frailty and sarcopenia result from age-related decline in physiological reserve and can be associated with complications after elective spine surgery. Little is known about the impact of these factors on patient-reported outcomes (PROs).

METHODS

Patients older than 70 years of age undergoing elective lumbar spine surgery were included. The modified 5-item frailty index (mFI-5) was calculated. Sarcopenia was defined using total psoas index, which is obtained by dividing the mid L3 total psoas area by VB area (L3-TPA/VB). PROs included Oswestry disability index (ODI), EuroQual-5D (EQ-5D), numeric rating scale (NRS)-back pain, NRS leg pain (LP), and North American Spine Society (NASS) at postoperative 12 months. Clinical outcomes included length of stay (LOS), 90-day readmission and complications. Univariate and multivariable regression analyses were performed.

RESULTS

Total 448 patients were included. The mean mFI-5 index was 1.6±1.0 and mean total psoas index was 1.7±0.5. There was a significant improvement in all PROs from baseline to 12 months ( P <0.0001). After adjusting for age, body mass index, smoking status, levels fused, and baseline PROs, higher mFI-5 index was associated with higher 12-month ODI ( P <0.001), lower 12-month EQ-5D ( P =0.001), higher NRS-L P ( P =0.039), and longer LOS ( P =0.007). Sarcopenia was not associated with 12-month PROs or LOS. Neither sarcopenia or mFI-5 were associated with 90-day complication and readmission.

CONCLUSIONS

Elderly patients demonstrate significant improvement in PROs after elective lumbar spine surgery. Frailty was associated with worse 12 months postoperative ODI, EQ-5D, NRS-LP scores, and longer hospital stay. While patients with sarcopenia can expect similar outcomes compared with those without, the mFI-5 should be considered preoperatively in counseling patients regarding expectations for disability, health-related quality of life, and leg pain outcomes after elective lumbar spine surgery.

LEVEL OF EVIDENCE

3.

A Risk Calculator for the Prediction of C5 Nerve Root Palsy After Instrumented Cervical Fusion

BACKGROUND

C5 palsy is a common postoperative complication after cervical fusion and is associated with increased health care costs and diminished quality of life. Accurate prediction of C5 palsy may allow for appropriate preoperative counseling and risk stratification. We primarily aim to develop an algorithm for the prediction of C5 palsy after instrumented cervical fusion and identify novel features for risk prediction. Additionally, we aim to build a risk calculator to provide the risk of C5 palsy.

METHODS

We identified adult patients who underwent instrumented cervical fusion at a tertiary care medical center between 2013 and 2020. The primary outcome was postoperative C5 palsy. We developed ensemble machine learning, standard machine learning, and logistic regression models predicting the risk of C5 palsy-assessing discrimination and calibration. Additionally, a web-based risk calculator was built with the best-performing model.

RESULTS

A total of 1024 patients were included, with 52 cases of C5 palsy. The ensemble model was well-calibrated and demonstrated excellent discrimination with an area under the receiver-operating characteristic curve of 0.773. The following features were the most important for ensemble model performance: diabetes mellitus, bipolar disorder, C5 or C4 level, surgical approach, preoperative non-motor neurologic symptoms, degenerative disease, number of fused levels, and age.

CONCLUSIONS

We report a risk calculator that generates patient-specific C5 palsy risk after instrumented cervical fusion. Individualized risk prediction for patients may facilitate improved preoperative patient counseling and risk stratification as well as potential intraoperative mitigating measures. This tool may also aid in addressing potentially modifiable risk factors such as diabetes and obesity.

Subcutaneous Fat Thickness on Erect Radiographs Is a Predictor of Infection Following Elective Posterior Lumbar Fusion

BACKGROUND

Posterior lumbar fusions are a common and successful procedure, yet surgical site infection (SSI) is still prevalent and causes significant morbidity. Obesity is a well-established risk factor for SSI. Still, the accuracy of the body mass index (BMI) caused some to suggest other metrics that are more representative of the thickness of the soft-tissue envelope in the surgical site.

METHODS

A retrospective review of all cases that developed SSI following posterior lumbar fusion over the past 5 years was done. An age and gender-matched control group was formed from the lumbar fusion cases that did not develop SSI. Demographic and clinical data were collected, and morphometric measurements of the soft-tissue envelope were performed at the level of L4 for all cases on standing x-ray imaging and magnetic resonance imaging (MRI).

RESULTS

A total of 366 patients underwent posterior lumbar fusion, 26 of whom developed SSI. BMI and skin to spinous process measurements on x-ray imaging-not MRI-were found to be significantly associated with SSI. Regression analysis further confirmed the strength of the association.

CONCLUSION

While BMI and MRI measurements are useful, wound depth measurements on x-ray imaging can be predictive of SSI in lumbar fusion cases.

CLINICAL RELEVACE

Wound depth measurements are predictive of lumbar wound infection. The information within this study can help surgeons better predict and manage infections of posterior lumbar wounds.

LEVEL OF EVIDENCE: 3

Diabetes management in spinal surgery

Diabetes mellitus can lead to long-standing complications in multiple arenas. An area that is often overlooked is implications for major surgery. Spinal decompression and fusions have unique challenges in the diabetic patient. In this review, we briefly highlight the pathophysiology of diabetes mellitus prior to examining implications for spinal surgery. We focus on the wound healing process, surgical infection risk, and delayed fusion. The paper then transitions to a focus on early diagnostics as well as pre-operative glucose control. Finally, we highlight important management strategies post operatively, continued necessity of monitoring, and emerging treatment and diagnostic approaches. This paper will serve as a key clinical guide that clinicians can utilize for diagnostic, management, and follow-up planning.

Postoperative Glycemic Variability as a Predictor of Adverse Outcomes Following Lumbar Fusion

STUDY DESIGN

A retrospective cross-sectional study.

OBJECTIVE

This study aims to evaluate the effect size of postoperative glycemic variability on surgical outcomes among patients who have undergone one- to three-level lumbar fusion.

SUMMARY OF BACKGROUND DATA

While numerous patient characteristics have been associated with surgical outcomes after lumbar fusion, recent studies have described the measuring of postoperative glycemic variability as another promising marker.

METHODS

A total of 850 patients were stratified into tertiles (low, moderate, high) based on degree of postoperative glycemic variability defined by coefficient of variation (CV). Surgical site infections were determined via chart review based on the Centers for Disease Control and Prevention definition. Demographic factors, surgical characteristics, inpatient complications, readmissions, and reoperations were determined by chart review and telephone encounters.

RESULTS

Overall, a statistically significant difference in 90-day adverse outcomes was observed when stratified by postoperative glycemic variability. In particular, patients with high CV had a higher odds ratio (OR) of readmission (OR = 2.19 [1.17, 4.09]; P = 0.01), experiencing a surgical site infection (OR = 3.22 [1.39, 7.45]; P = 0.01), and undergoing reoperations (OR = 2.65 [1.34, 5.23]; P = 0.01) compared with patients with low CV. No significant association was seen between low and moderate CV groups. Higher CV patients were more likely to experience longer hospital stays (β: 1.03; P = 0.01). Among the three groups, high CV group experienced the highest proportion of complications.

CONCLUSION

Our study establishes a significant relationship between postoperative glycemic variability and inpatient complications, length of stay, and 90-day adverse outcomes. While HbA1c has classically been used as the principal marker to assess blood glucose control, our results show CV to be a strong predictor of postoperative adverse outcomes. Future high-quality, prospective studies are necessary to explore the true effect of CV, as well as its practicality in clinical practice. Nevertheless, fluctuations in blood glucose levels during the inpatient stay should be limited to improve patient results.Level of Evidence: 4.

Preoperative diabetes complicates postsurgical recovery but does not amplify readmission risk following pancreatic surgery

BACKGROUND

Diabetes is a significant and prevalent medical condition associated with increased comorbidities, longer hospital length of stay, and higher healthcare costs. We aimed to assess the association between diabetes mellitus and postoperative outcomes following pancreatic surgeries.

METHODS

Records for patients with major elective pancreatic surgeries were retrieved retrospectively from the Nationwide Readmission Database (2010-2014). Association of diabetic status with postoperative complications, in-hospital mortality, length of stay (LOS), readmission rate, and hospital costs were investigated. Logistic regression and decision tree analyses were employed to predict adverse outcomes.

RESULTS

A total of 8,401 patients who had pancreatic surgery were included. They were categorized according to their diabetic diagnosis. Results showed that diabetic patients had a higher risk of postoperative complications compared to non-diabetics (OR: 1.27, 95% CI: 1.08-1.49, P=0.003). Bleeding and renal complications were the most significant. Uncontrolled diabetes significantly required a longer hospital stay (9.17±4.28 vs. 8.03±4.96 days, P=0.001), and incurred higher hospital costs ($34,171.04±$20,846.61 vs. $28,182.21±$24,070.27, P=0.001). After multivariate regression, no association was found with in-hospital mortality or readmission rates; however, diabetic patients' length of stay during readmission was increased at 30- and 90-day readmissions (P=0.004 and 0.007, respectively).

CONCLUSIONS

Among patients who underwent pancreatic surgery, those with diabetes had a higher rate of postoperative complications compared to non-diabetics. Additionally, diabetic patients had higher hospital charges and costs during primary admission. Initial analysis of patients with diabetes showed they had higher rates of 30- and 90-day readmissions, though this did not maintain significance after regression analysis. Exploring the mechanisms underlying this finding would aid in preventing postoperative complications and reducing healthcare costs.

Diabetes mellitus and perioperative outcomes: a scoping review of the literature

BACKGROUND

Diabetes mellitus (DM) is frequently encountered in the perioperative period. DM may increase the risk of adverse perioperative outcomes owing to the potential vascular complications of DM. We conducted a scoping review to examine the association between DM and adverse perioperative outcomes.

METHODS

A systematic search strategy of the published literature was built and applied in multiple databases. Observational studies examining the association between DM and adverse perioperative outcomes were included. Abstract screening determined full texts suitable for inclusion. Core information was extracted from each of the included studies including study design, definition of DM, type of DM, surgical specialties, and outcomes. Only primary outcomes are reported in this review.

RESULTS

The search strategy identified 2363 records. Of those, 61 were included and 28 were excluded with justification. DM was mostly defined by either haemoglobin A1c (HbA1c) or blood glucose values (19 studies each). Other definitions included 'prior diagnosis' or use of medication. In 17 studies the definition was unclear. Type 2 DM was the most frequently studied subtype. Five of seven studies found DM was associated with mortality, 5/13 reported an association with 'complications' (as a composite measure), and 12/17 studies found DM was associated with 'infection'. Overall, 33/61 studies reported that DM was associated with the primary outcome measure.

CONCLUSION

Diabetes mellitus is inconsistently defined in the published literature, which limits the potential for pooled analysis. Further research is necessary to determine which cohort of patients with DM are most at risk of adverse postoperative outcomes, and how control influences this association.

Outcome Measures of Medicare Patients With Diabetes Mellitus Undergoing Thoracolumbar Deformity Surgery

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

The objective of this study was to identify the impact of diabetes on postoperative outcomes in Medicare patients undergoing adult spinal deformity (ASD) surgery.

METHODS

We queried the MarketScan Medicare database to identify patients who underwent ASD surgery from 2007 to 2016. Patients were then stratified based on diabetes status at the time of the index operation. Patients not enrolled in the Medicare dataset and those with any prior history of trauma or tumor were excluded from this study.

RESULTS

A total of 2564 patients met the inclusion criteria of this study, of which n=746 (29.1.%) were diabetic. Patients with diabetes had a higher rate of postoperative infection than nondiabetic patients (3.1% vs. 1.7%, P<0.05) within 90 days. Renal complications were also more elevated in the diabetic cohort (3.2% vs. 1.3%, P<0.05). Readmission rates were significantly higher in the diabetes cohort through of 60 days (15.2% vs. 11.8%, P<0.05) and 90 days (17.0% vs. 13.4%, P<0.05). When looking specifically at the outpatient payments, patients with diabetes did have a higher financial burden at 60 days ($8147 vs. $6956, P<0.05) and 90 days ($10,126 vs. $8376, P<0.05).

CONCLUSIONS

In this study, diabetic patients who underwent ASD surgery had elevated rates of postoperative infection, outpatient costs, and rates of readmissions within 90 days. Further research should investigate the role of poor glycemic control on spine surgery outcomes.

Spine Surgery and Preoperative Hemoglobin, Hematocrit, and Hemoglobin A1c: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

Synthesize previous studies evaluating clinical utility of preoperative Hb/Hct and HbA1c in patients undergoing common spinal procedures: anterior cervical discectomy and fusion (ACDF), posterior cervical fusion (PCF), posterior lumbar fusion (PLF), and lumbar decompression (LD).

METHODS

We queried PubMed, Embase, Cochrane Library, and Web of Science for literature on preoperative Hb/Hct and HbA1c and post-operative outcomes in adult patients undergoing ACDF, PCF, PLF, or LD surgeries.

RESULTS

Total of 4,307 publications were assessed. Twenty-one articles met inclusion criteria.

PCF AND ACDF

Decreased preoperative Hb/Hct were significant predictors of increased postoperative morbidity, including return to operating room, pulmonary complications, transfusions, and increased length of stay (LOS). For increased HbA1c, there was significant increase in risk of postoperative infection and cost of hospital stay.

PLF

Decreased Hb/Hct was reported to be associated with increased risk of postoperative cardiac events, blood transfusion, and increased LOS. Elevated HbA1c was associated with increased risk of infection as well as higher visual analogue scores (VAS) and Oswestry disability index (ODI) scores.

LD

LOS and total episode of care cost were increased in patients with preoperative HbA1c elevation.

CONCLUSION

In adult patients undergoing spine surgery, preoperative Hb/Hct are clinically useful predictors for postoperative complications, transfusion rates, and LOS, and HbA1c is predictive for postoperative infection and functional outcomes. Using Hct values <35-38% and HbA1c >6.5%-6.9% for identifying patients at higher risk of postoperative complications is most supported by the literature. We recommend obtaining these labs as part of routine pre-operative risk stratification.

LEVEL OF EVIDENCE

III.

Is Uncontrolled Diabetes Mellitus Associated with Incidence of Complications After Posterior Instrumented Lumbar Fusion? A National Claims Database Analysis

BACKGROUND

Previous research has shown that diabetes mellitus (DM) is associated with postoperative complications, including surgical site infections (SSIs). However, evidence for the association between diabetes control and postoperative complications in patients with DM is mixed. Prior studies relied on a single metric for defining uncontrolled DM, which does not account for glycemic variability, and it is unknown whether a more comprehensive assessment of diabetes control is associated with postoperative complications.

QUESTIONS/PURPOSES

(1) Is there a difference in the incidence of SSI after lumbar spine fusion in patients with uncontrolled DM, defined with a comprehensive assessment of glycemic control, compared with patients with controlled DM? (2) Is there a difference in the incidence of other select postoperative complications after lumbar spine fusion in patients with uncontrolled DM compared with patients with controlled DM? (3) Is there a difference in total reimbursements between these groups?

METHODS

We used the PearlDiver Patient Records Database, a national administrative claims database that provides access to the full continuum of perioperative care. We included 46,490 patients with DM undergoing posterior lumbar fusion with instrumentation. Patients were required to be continuously enrolled in the database for at least 1 year before and 90 days after the index procedure. Patients were divided into uncontrolled and controlled DM cohorts, as defined by ICD-9 diagnostic codes. These are based on a comprehensive assessment of glycemic control, including consideration of patient self-monitoring of blood glucose levels, hemoglobin A1c, and the presence/severity of diabetes-related comorbidities. The cohorts differed only by age, insurance type, and Elixhauser comorbidity score. The primary outcome was the incidence of SSI, divided into superficial and deep, within 90 days postoperatively. Secondary complications included the incidence of cerebrovascular events, acute kidney injury, pulmonary embolism, pneumonia, urinary tract infection, blood transfusion, and total reimbursements. These are the sum of reimbursements occurring within 90 days of surgery, which capture the total professional and facility cost burden to the health payer (such as the insurer). We constructed multivariable logistic regression models to adjust for the effects of age, insurance type, and comorbidities.

RESULTS

After adjusting for potentially confounding variables including age, insurance type, and comorbidities, we found that patients with uncontrolled DM had an odds ratio for deep SSI of 1.52 (95% confidence interval 1.16 to 1.95; p = 0.002). Similarly, patients with uncontrolled DM had adjusted odds ratios of 1.25 (95% CI 1.01 to 1.53; p = 0.03) for cerebrovascular events, 1.36 (95% CI 1.18 to 1.57; p < 0.001) for acute kidney injury, 1.55 (95% CI 1.16 to 2.04; p = 0.002) for pulmonary embolism, 1.30 (95% CI 1.08 to 1.54; p = 0.004) for pneumonia, 1.33 (95% CI 1.19 to 1.49; p < 0.001) for urinary tract infection, and 1.27 (95% CI 1.04 to 1.53; p = 0.02) for perioperative transfusion. Patients with uncontrolled DM had higher median 90-day total reimbursements than patients with controlled DM: USD 27,915 (interquartile range 5472 to 63,400) versus USD 10,263 (IQR 4101 to 49,748; p < 0.001).

CONCLUSION

Our findings encourage surgeons to take a full diabetic history beyond the HbA1c value, including any self-monitoring of glucose measurements, time in acceptable range for continuous glucose monitors, and/or consideration of the presence/severity of diabetes-related complications before lumbar spine fusion, as HbA1c does not fully capture glycemic control or variability. We emphasize that uncontrolled DM is a clinical, rather than laboratory, diagnosis. Comprehensive diabetes histories should be incorporated into existing preoperative diabetes care pathways and elective surgery could be deferred to improve glycemic control. Future development of an index measure incorporating multidimensional measures of diabetes control (such as continuous or self-glucose monitoring, diabetes-related comorbidities) is warranted.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Quality gaps in screening and monitoring for postoperative hyperglycemia in a Canadian hospital: a retrospective cohort study

INTRODUCTION

Evidence-based preoperative, intraoperative and postoperative glycemic management may reduce poor surgical outcomes. Previous studies suggest that quality gaps in perioperative glycemic management may be common.

RESEARCH DESIGN AND METHODS

This retrospective cohort study used administrative health and laboratory data from a single center to estimate quality gaps in perioperative glycemic management in patients with and without diabetes between April 2019 and March 2020. We examined the proportion of patients with preoperative hemoglobin A1c (HbA1c) measurement, postoperative point-of-care testing (POCT) for glucose, hyperglycemia, and basal bolus insulin regimens. We compared the median length of stay (LOS) in patients with and without postoperative hyperglycemia, adjusted for age and sex.

RESULTS

There were 6576 patients in our cohort; 1165 (17.8%) had diabetes. Most patients with diabetes had an HbA1c measured prior to surgery (n=697, 59.8%). Postoperatively, 16.9% of patients with diabetes had no POCT monitoring (n=197) and 65.7% had hyperglycemia (n=636). Only 35.9% of patients who received insulin had a basal bolus insulin regimen (n=229). Patients with diabetes who had postoperative hyperglycemia had a longer median LOS compared with those who did not have postoperative hyperglycemia (8.4 days (95% CI 7.5 to 9.4) and 6.7 days (95% CI 6.3 to 7.1), respectively). In patients without diabetes, median LOS was 7.4 days (95% CI 4.4 to 10.4) for those with hyperglycemia and 5.2 days (95% CI 5.1 to 5.4) for those with in-target glucose.

CONCLUSIONS

Quality gaps in perioperative glycemic management include measurement of blood glucose after surgery and treatment of postoperative hyperglycemia. These gaps may contribute to longer LOS.

Incidence and Clinical Outcomes of Hypothyroidism in Patients Undergoing Spinal Fusion

Background

Hypothyroidism has been independently associated with the development of several comorbidities and is known to increase complication rates in non-spinal surgeries. However, there are limited data regarding the effects of hypothyroidism in major spine surgery. Therefore, we present the largest retrospective analysis evaluating outcomes in hypothyroid patients undergoing spinal fusion.

Methods

A retrospective review of the National Inpatient Sample (NIS) from 2004-2014 was performed. Patients with an International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) procedure code indicating spinal fusion (81.04-81.08, 81.34-81.38, 81.0x, 81.3x) were included. Patients with an ICD-9-CM diagnosis code indicating hypothyroidism (244.x) were compared to those without. Cervical and lumbar fusions were evaluated independently. Significant covariates in univariable logistic regression were utilized to construct multivariable models to analyze the effect of hypothyroidism on perioperative morbidity and mortality.

Results

A total of 4,149,125 patients were identified, of which 9.4% were hypothyroid. Although, hypothyroid patients had a higher risk of hematologic complications (lumbar - odds ratio [OR] 1.176, p < 0.0001; cervical - OR 1.162, p < 0.0001), they exhibited decreased in-hospital mortality (lumbar - OR .643, p < 0.0001; cervical - OR .606, p < 0.0001). Hypothyroid lumbar fusion patients also demonstrated decreased rates of perioperative myocardial infarction (MI) (OR .851, p < 0.0001). All these results were independent of patient gender.

Conclusions

Hypothyroid patients undergoing spinal fusion demonstrated lower rates of inpatient mortality and, in lumbar fusions, also had lower rates of acute MI when compared to their euthyroid counterparts. This suggests that hypothyroidism may offer protection against all-cause mortality and may be cardioprotective in the postoperative period for lumbar spinal fusions independent of patient gender.

Preoperative HbA1c > 8% Is Associated With Poor Outcomes in Lumbar Spine Surgery: A Michigan Spine Surgery Improvement Collaborative Study

BACKGROUND

Preoperative hemoglobin A1c (HbA1c) is a useful screening tool since a significant portion of diabetic patients in the United States are undiagnosed and the prevalence of diabetes continues to increase. However, there is a paucity of literature analyzing comprehensive association between HbA1c and postoperative outcome in lumbar spine surgery.

OBJECTIVE

To assess the prognostic value of preoperative HbA1c > 8% in patients undergoing elective lumbar spine surgery.

METHODS

The Michigan Spine Surgery Improvement Collaborative (MSSIC) database was queried to track all elective lumbar spine surgeries between January 2018 and December 2019. Cases were divided into 2 cohorts based on preoperative HbA1c level (≤8% and >8%). Measured outcomes include any complication, surgical site infection (SSI), readmission (RA) within 30 d (30RA) and 90 d (90RA) of index operation, patient satisfaction, and the percentage of patients who achieved minimum clinically important difference (MCID) using Patient-Reported Outcomes Measurement Information System.

RESULTS

We captured 4778 patients in this study. Our multivariate analysis demonstrated that patients with HbA1c > 8% were more likely to experience postoperative complication (odds ratio [OR] 1.81, 95% CI 1.20-2.73; P = .005) and be readmitted within 90 d of index surgery (OR 1.66, 95% CI 1.08-2.54; P = .021). They also had longer hospital stay (OR 1.12, 95% CI 1.03-1.23; P = .009) and were less likely to achieve functional improvement after surgery (OR 0.64, 95% CI 0.44-0.92; P = .016).

CONCLUSION

HbA1c > 8% is a reliable predictor of poor outcome in elective lumbar spine surgery. Clinicians should consider specialty consultation to optimize patients' glycemic control prior to surgery.

Association of Preoperative Hemoglobin A1c and Body Mass Index with Wound Infection Rate in Spinal Surgery

BACKGROUND

The deleterious effect of diabetes mellitus on surgical outcomes is well documented for joint replacement surgery. We analyzed the large national US Department of Veterans Affairs (VA) database for patients who had undergone elective spinal surgery.

METHODS

We retrospectively searched the VA database and identified 174 520 spine cases.

RESULTS

There were 7766 (4.5%) wound infections and 49 271 (28%) had hemoglobin A1c (HbA1c) testing (range: 3.0-17.8) prior to surgery. In the preoperative HbA1c-checked group, there were 2941 (6.0% of 49 271) infections and in the without-preoperative HbA1c group, there were 4825 (3.9% of 125 249) infections. The distribution of infections was significantly different (χ² = 372.577, P < .0001) and suggests a 2.12% increase in the absolute risk of infection based on the presence of preoperative HbA1c testing, regardless of the result. Logistic regression revealed a preoperative HbA1c test was associated with an odds ratio of 1.435 for infection (confidence interval 1.367-1.505, P < .0001). In a separate model based on HbA1c levels, we found that HbA1c is a significant predictor of infection with an odds ratio of 1.042 (confidence interval 1.017-1.068, P = .0009) for each 1% increase in the test result. This analysis differs from using a strict cutoff value of HbA1c of 6.5%. Similar testing for body mass index and age yielded an odds ratio of 1.027 for each increase of 1 kg/m² and an odds ratio of 1.009 for each 1-year increase in age respectively.

CONCLUSIONS

Hemoglobin A1c testing, HgA1c value, body mass index, and age all contribute to the risk of wound infection after elective spine surgery in a large national VA population. These data can be used to estimate surgical risks and to aid in patient counseling about proposed spine surgery.

LEVEL OF EVIDENCE

4.

Risk factors for reoperation after lumbar total disc replacement at short-, mid-, and long-term follow-up

BACKGROUND CONTEXT

The reoperation rate following TDR (Total Disc replacement) has been established at short- and mid-term time points through the Food and Drug Administration Investigational Device Exemption (FDA IDE) trials. However, these trials include highly selected centers and surgeons with strict governance of indications. The utilization of TDR throughout the community needs further analysis.

PURPOSE

To identify the risk factors for lumbar spine reoperation in patients undergoing lumbar total disc replacement (TDR) at short-, mid-, and long-term follow-up.

STUDY DESIGN/SETTING

This study is a multi-center retrospective cohort study utilizing the New York Statewide Planning and Research Cooperative System database.

PATIENT SAMPLE

We identified 1,368 patients who underwent an elective primary lumbar TDR in New York State between January 1, 2005 and September 30, 2013.

OUTCOME MEASURES

The primary functional outcome of interest was lumbar reoperation, specifically the evaluation of independent risk factors for lumbar reoperation at a minimum of 2 years, with sub-analyses performed at 5 and ten years.

METHODS

International Classification of Diseases, Ninth revision codes were utilized to identify patients undergoing a primary lumbar TDR. We excluded patients with primary/revision lumbar fusion procedures and revision disc replacement procedures. Hospital academic status was determined by the Accreditation Council for Graduate Medical Education. Unique encrypted patient identifiers allowed for longitudinal follow-up for reoperation. Logistic regression models compared reoperation and no-reoperation cohorts, and were performed on sub-analyses for significant univariate predictors of reoperation.

RESULTS

Between January 2005 and September 2013, 1368 patients underwent a primary lumbar TDR. Reoperation occurred in 8.8% by 2 years, 15.8% by 5 years, and 19.5% by ten years. Diabetics were more likely to have reoperations (7.5% vs 3.8%, p=.013). Teaching hospitals experienced a decreased reoperation rate compared to nonteaching hospitals at 2-year (5.0% vs 10.5%, p=.002), 5-year (10.7% vs 17.9%, p=.002) and 10-year (11.7% vs 21.9%, p=.045) follow-up. Lumbar fusion was the most common reoperation (14.2%).

CONCLUSION

We identified an 8.8% reoperation rate after inpatient lumbar TDR at 2-years, 15.8% at 5-years, and 19.5% at 10-years. When stratifying by teaching status, reoperation rates at teaching centers align with those reported in FDA IDE studies. Diabetes was the only patient factor influencing reoperation rate. There is a growing consensus that lumbar TDR is a durable and appropriate surgical option for lumbar degenerative disc disease. Proper indications are crucial to obtaining good outcomes with lumbar TDR.

Anterior Versus Posterior Decompression for Degenerative Thoracic Spine Diseases: A Comparison of Complications

STUDY DESIGN

Retrospective database.

OBJECTIVES

Although posterior decompression is the most common approach for surgical treatment of degenerative thoracic spine disease, anterior approach is gaining interest due to its advantage in disc visualization. The objective of this study was to compare the intra- and postoperative medical complication rates between anterior and posterior decompression for degenerative thoracic spine pathologies.

METHODS

A national US insurance database was queried for patients with degenerative diagnoses who had undergone anterior or posterior thoracic decompression. Incidence of intra- and postoperative complications were evaluated on the day of surgery and within 1 and 3 months. Two subgroups were matched based on age, gender, and comorbidity. The association of decompression approach and complications was assessed using logistic regression.

RESULTS

A total of 1459 patients were included, consisting of 1004 patients in posterior and 455 patients in anterior group. Respiratory complications were the most common complications on the day of surgery (8.57%) and within 30 days (17.75%). Matched analysis showed that anterior approach was associated with organ failure, gastrointestinal, and device-/implant-/graft-related complications in all follow-up periods; and with cardiovascular, deep venous thrombosis/pulmonary embolism, and respiratory complications in at least 1 follow-up period. Among respiratory complications, anterior decompression was significantly associated with noninfectious etiologies on the day of surgery (odds ratio [OR] = 1.72), within 30 days (OR = 2.05), and within 90 days (OR = 1.92).

CONCLUSIONS

Anterior approach was associated with increased rates of several complications. High rates of respiratory complications necessitate comprehensive preoperative risk stratification to identify those who may benefit more from posterior approach.

Predictors of Readmission and Prolonged Length of Stay After Cervical Disc Arthroplasty

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of the study was to assess which factors increase risk of readmission within 30 days of surgery or prolonged length of stay (LOS) (≥2 days) after cervical disc arthroplasty (CDA).

SUMMARY OF BACKGROUND DATA

Several studies have shown noninferiority at mid- and long-term outcomes after cervical disc arthroplasty (CDA) compared to anterior cervical discectomy and fusion ACDF, but few have evaluated short-term outcomes regarding risk of readmission or prolonged LOS after surgery.

METHODS

Demographics, comorbidities, operative details, postoperative complications, and perioperative outcomes were collected for patients undergoing single level CDA in the National Surgical Quality Improvement Program (NSQIP) database. Patients with prolonged LOS, defined as >2 days, and readmission within 30 days following CDA were identified. Univariable and multivariable logistic regression models were used to identify risk factors for prolonged LOS and readmission.

RESULTS

A total of 3221 patients underwent single level CDA. Average age was 45.6 years (range 19-82) and 53% of patients were male. A total of 472 (14.7%) experienced a prolonged LOS and 36 (1.1%) patients were readmitted within 30 days following surgery. Predictors of readmission were postoperative superficial wound infection (odds ratio [OR] = 73.83, P < 0.001), American Society of Anesthesiologists (ASA) classification (OR = 1.98, P = 0.048), and body mass index (BMI) (OR = 1.06, P = 0.02). Female sex (OR = 1.76, P < 0.001), diabetes (OR = 1.50, P = 0.024), postoperative wound dehiscence (OR = 13.11, P = 0.042), ASA class (OR = 1.43, P < 0.01), and operative time (OR = 1.01, P < 0.001) were significantly associated with prolonged LOS.

CONCLUSION

From a nationwide database analysis of 3221 patients, wound complications are predictors of both prolonged LOS and readmission. Patient comorbidities, including diabetes, higher ASA classification, female sex, and higher BMI also increased risk of prolonged LOS or readmission.Level of Evidence: 3.

Diabetes is associated with greater leg pain and worse patient-reported outcomes at 1 year after lumbar spine surgery

Although patients with diabetes reportedly have more back pain and worse patient-reported outcomes than those without diabetes after lumbar spine surgery, the impact of diabetes on postoperative recovery in pain or numbness in other regions is not well characterized. In this study, the authors aimed to elucidate the impact of diabetes on postoperative recovery in pain/numbness in four areas (back, buttock, leg, and sole) after lumbar spine surgery. The authors retrospectively reviewed 993 patients (152 with diabetes and 841 without) who underwent decompression and/or fixation within three levels of the lumbar spine at eight hospitals during April 2017–June 2018. Preoperative Numerical Rating Scale (NRS) scores in all four areas, Oswestry Disability Index (ODI), and Euro quality of life 5-dimension (EQ-5D) were comparable between the groups. The diabetic group showed worse ODI/EQ-5D and greater NRS scores for leg pain 1 year after surgery than the non-diabetic group. Although other postoperative NRS scores tended to be higher in the diabetic group, the between-group differences were not significant. Diabetic neuropathy caused by microvascular changes may induce irreversible nerve damage especially in leg area. Providers can use this information when counseling patients with diabetes about the expected outcomes of spine surgery.

Understanding variations and influencing factors on length of stay for T2DM patients based on a multilevel model

Aim

Shortening the length of stay (LOS) is a potential and sustainable way to relieve the pressure that type 2 diabetes mellitus (T2DM) patients placed on the public health system.

Method

Multi-stage random sampling was used to obtain qualified hospitals and electronic medical records for patients discharged with T2DM in 2018. A box-cox transformation was adopted to normalize LOS. Multilevel model was used to verify hospital cluster effect on LOS variations and screen potential factors for LOS variations from both individual and hospital levels.

Result

50 hospitals and a total of 12,888 T2DM patients were included. Significant differences in LOS variations between hospitals, and a hospital cluster effect on LOS variations (t = 92.188, P<0.001) was detected. The results showed that female patients, patients with new rural cooperative’ medical insurance, hospitals with more beds, and hospitals with faster bed turnovers had shorter LOS. Conversely, elderly patients, patients with urban workers’ medical insurance, patients requiring surgery, patients with the International Classification of Diseases coded complication types E11.1, E11.2, E11.4, E11.5, and other complications cardiovascular diseases, grade III hospitals, hospitals with a lower doctor-to-nurse ratio, and hospitals with more daily visits per doctor had longer LOS.

Conclusions

The evidence proved that hospital cluster effect on LOS variation did exist. Complications and patients features at individual level, as well as organization and resource characteristics at hospital level, had impacted LOS variations to varying degrees. To shorten LOS and better meet the medical demand for T2DM patients, limited health resources must be allocated and utilized rationally at hospital level, and the patients with the characteristics of longer LOS risk must be identified in time. More influencing factors on LOS variations at different levels are still worth of comprehensive exploration in the future.

Assessing the Impact of Neurogenic Claudication on Outcomes Following Decompression With Lumbar Interbody Fusions in Patients With Lumbar Spinal Stenosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To conduct the first comprehensive national-level study examining specific risks, outcomes, and costs surrounding surgical treatment of lumar spinal stenosis (LSS) in patients with and without neurogenic claudication (NC).

METHODS

Data for patients with or without NC who underwent decompression with a lumbar interbody fusion approached anteriorly (ALIF), posteriorly (PLIF), or laterally (LLIF) for LSS was collected from the 2013-2014 National Inpatient Sample using International Classification of Disease codes.

RESULTS

A total of 121 025 LSS cases without NC and 20 095 cases with NC were included in this study. The most significant complications associated with NC status by organ system included renal (P = .0030) and hematological complications (P = .0003). Multivariate regression controlling for key demographic and comorbidity variables showed that patients with NC did not have significantly higher odds of complication, non-home discharge, or extended hospitalization compared to patients without NC regardless of fusion type. Interestingly, NC patients had comparatively lower total charges for their hospitalization following PLIFs (P = .0001) and LLIFs (P < .0001), but not ALIFs (P = .6121).

CONCLUSION

NC does not appear to significantly increase odds of adverse outcomes following fusion in LSS. Given the large prevalence of LSS and coincidental NC, these findings may carry important implications in managing this challenging patient population and justifies future prospective investigation of this topic.

Prolonged length of stay and discharge disposition to rehabilitation facilities following single-level posterior lumbar interbody fusion for acquired spondylolisthesis

Background

Acquired lumbar spondylolisthesis is often treated with interbody fusion. However, few studies have evaluated predictors for prolonged length of stay (LOS) and disposition to rehabilitation facilities after posterior single-level lumbar interbody fusion for acquired spondylolisthesis.

Methods

The American College of Surgeons National Quality Improvement Program database was queried for adults with acquired spondylolisthesis who underwent single-level lumbar interbody fusion through a posterior approach (posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion [TLIF]). We utilized multivariate logistic regression analysis to identify predictors of prolonged LOS and disposition in this patient population.

Results

Among 2080 patients identified, 700 (33.7%) had a prolonged LOS (≥4 days), and 306 (14.7%) were discharged postoperatively to rehabilitation facilities. Predictors for prolonged LOS included: American Society of Anesthesiologist (ASA) class ≥3, anemia, prolonged operative time, perioperative blood transfusion, pneumonia, urinary tract infections, and return to the operating room. The following risk factors predicted discharge to postoperative rehabilitation facilities: age ≥65 years, male sex, ASA class ≥3, modified frailty score ≥2, perioperative blood transfusion, and prolonged LOS.

Conclusion

Multiple partial-overlapping risk factors predicted prolonged LOS and discharge to rehabilitation facilities after single-level TLIF/PLIF performed for acquired spondylolisthesis.

Medical optimization of modifiable risk factors before thoracolumbar three-column osteotomies: an analysis of 195 patients

PURPOSE

To determine the rate of preoperative modifiable laboratory abnormalities (both major and minor) and the association with early postoperative medical and surgical complications.

METHODS

All patients undergoing thoracolumbar three-column osteotomy between 2013 and 2016 with preoperative laboratory data were identified. Potential preoperative modifiable laboratory abnormalities (major and minor) were assessed including hyponatremia (sodium < 130 and < 135 mEq/L), anemia (hematocrit < 25% and < 30%), renal insufficiency (creatinine ≥ 1.8 and ≥ 1.2 mg/dL), coagulopathy (INR ≥ 1.8 and ≥ 1.2), and hypoalbuminemia (albumin < 2.5 and < 3.5 g/dL). Multivariate logistic regression was used to determine associations with 30-day complications after controlling for possible confounding factors.

RESULTS

A total of 195 patients were identified. The rates of major and minor preoperative laboratory abnormalities were 7.7% and 31.3%, respectively. The rates of serious medical, minor medical, and surgical complications over 30-days were 6.7%, 21.5%, and 10.3%, respectively. In multivariate analysis the presence of major preoperative laboratory abnormalities had a significant association with serious medical complications (odds ratio [OR] 77.8, P < 0.001), and minor medical complications (OR 13.3, P < 0.001), but not surgical complications (P = 0.243). The presence of minor preoperative laboratory abnormalities had a significant association with serious medical complications (OR 10.4, P = 0.041) and minor medical complications (OR 2.4, P = 0.045), but not surgical complications (P = 0.490).

CONCLUSIONS

While major laboratory abnormalities had a strong association with complications, even minor modifiable laboratory abnormalities had a significant association with both serious and minor medical complications.

Impact of Cirrhosis on Morbidity and Mortality After Spinal Fusion

STUDY DESIGN

Retrospective large database study.

OBJECTIVE

To determine the impact of cirrhosis on perioperative outcomes and resource utilization in elective spinal fusion surgery.

METHODS

Elective spinal fusion hospitalizations in patients with and without cirrhosis were identified using ICD-9-CM codes between the years of 2009 and 2011 using the Nationwide Inpatient Sample database. Main outcome measures were in-hospital neurologic, respiratory, cardiac, gastrointestinal, renal and urinary, pulmonary embolism, wound-related complications, and mortality. Length of stay and inpatient costs were also collected. Multivariable logistic regressions were conducted to compare the in-hospital outcomes of patients with and without cirrhosis undergoing spinal fusion.

RESULTS

A total of 1 214 694 patients underwent elective spinal fusions from 2009 to 2011. Oh these, 6739 were cirrhotic. Cirrhosis was a significant independent predictor for respiratory (odds ratio [OR] = 1.43, confidence interval [CI] 1.29-1.58; P < .001), gastrointestinal (OR = 1.72, CI 1.48-2.00; P < .001), urinary and renal (OR = 1.90, CI 1.70-2.12; P < 0.001), wound (OR = 1.36, CI 1.17-1.58; P < 0.001), and overall inpatient postoperative complications (OR = 1.43, CI 1.33-1.53; P < .001). Cirrhosis was also independently associated with significantly greater inpatient mortality (OR = 2.32, CI 1.72-3.14; P < .001). Cirrhotic patients also had significantly longer lengths of stay (5.35 vs 3.35 days; P < .001) and inpatient costs ($36 738 vs $29 068; P < .001).

CONCLUSIONS

Cirrhosis is associated with increased risk of perioperative complications, mortality and greater resource utilization. Cirrhotic patients undergoing spinal fusion surgeries should be counseled on these increased risks. Current strategies for perioperative management of cirrhotic patients undergoing spinal fusion surgery need improvement.

A Multi-Functional Implant Induces Bone Formation in a Diabetic Model

Patients with diabetes mellitus (DM) have defective healing of bone fractures. It was previously shown that nonviral gene delivery of plasmid DNA (pDNA) that independently encodes bone morphogenetic protein-2 (BMP-2) and fibroblast growth factor-2 (FGF-2), acts synergistically to promote bone regeneration in a DM animal model. Additionally, both insulin (INS) and the hormonally active form of vitamin D3, 1α,25-dihydroxyvitamin D3 (1α,25(OH)₂ D₃ ) (VD3) have independently been shown to play key roles in regulating bone fracture healing in DM patients. However, these individual therapies fail to adequately stimulate bone regeneration, illustrating a need for novel treatment of bone fractures in diabetic patients. Here, the ability of local delivery of INS and VD3 along with BMP-2 and FGF-2 genes is investigated to promote bone formation ectopically in Type-2 diabetic rats. A composite consisting of VD3 and INS is developed that contains poly(lactic-co-glycolic acid) microparticles (MPs) embedded in a fibrin gel surrounded by a collagen matrix that is permeated with polyethylenimine (PEI)-(pBMP-2+pFGF-2) nanoplexes. Using a submuscular osteoinduction model, it is demonstrated that local delivery of INS, VD3, and PEI-(pBMP-2+pFGF-2) significantly improves bone generation compared to other treatments, thusimplicating this approach as a method to promote bone regeneration in DM patients with bone fractures.

Diabetes Does Not Increase Complications, Length of Stay, or Hospital Costs After Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To determine if the presence of diabetes mellitus as comorbidity is associated with complications, inpatient length of stay, or direct hospital costs after minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

SUMMARY OF BACKGROUND DATA

Very few studies have investigated the effect of diabetes on complications, length of stay, or costs in minimally invasive lumbar surgeries.

METHODS

Patients undergoing primary, single-level MIS TLIF were retrospectively reviewed. Diabetic and nondiabetic patients were propensity matched in a 1:1 manner for age, sex, and comorbidity burden. An association between diabetic status and preoperative demographic or perioperative variables, including inpatient length of stay, was tested for using Student t test or χ analysis. Multivariate linear regression was used to test for an association between diabetic status and direct hospital costs.

RESULTS

After 1:1 propensity matching, 100 patients were included in this analysis. There were no significant differences in age, sex, body mass index, smoking status, or Charlson Comorbidity Index between propensity-matched patients with and without diabetes. In regards to the length of stay, no significant differences existed between diabetic and nondiabetic groups (68.7 vs. 58.3 h, P=0.218). No other significant differences existed in other perioperative variables including operative time, intraoperative blood loss, or complication rate (P≥0.05 for each). Multivariate analysis indicated that diabetic status was not associated with differences in total direct hospital costs (US$20,428 vs. US$20,429, P=0.792) or cost subcategories after MIS TLIF (P≥0.05 for each).

CONCLUSIONS

In this investigation, diabetes was not associated with postoperative complication rates, inpatient length of stay, or direct hospital costs after primary, single-level MIS TLIF. The reduced extent of operative exposure and tissue trauma in MIS TLIF may mitigate the risk of complications in diabetic patients, possibly preventing extensions in hospital stay length and associated hospital costs.

Risk factors for venous thromboembolism following spinal surgery: A meta-analysis

BACKGROUND

To investigate the risk factors for postoperative venous thromboembolism (VTE) in patients undergoing spinal surgery.

METHODS

Literature published in PubMed, Embase, the Cochrane Library, and Web of Science was systematically reviewed to assess risk factors for VTE following spinal surgery. The data analysis was conducted with STATA 12.0. Data were pooled using fixed-effects or random-effects models according to the heterogeneity among the included studies.

RESULTS

Twenty-six studies involving 3,216,187 patients were included in this meta-analysis, and the total incidence of VTE after spinal surgery was 0.35% (0.15-29.38%). The pooled analysis suggested that the incidence of VTE after spinal surgery was higher in such aspects as increasing age (weighted mean difference [WMD] 0.55 years, 95% confidence interval [CI] 0.33-0.78, P < .001), female sex (odds ratio [OR] 1.12, 95% CI 1.01-1.25; P = .034), diabetes (OR 1.34, 95% CI 1.29-1.44; P < .001), chronic kidney disease (OR = 8.31, 95% CI 1.98-34.93; P = .004), nonambulatory preoperative activity status (OR 3.67, 95% CI 2.75-4.83; P < .001), D-dimer level (WMD 1.023, 95% CI 0.162-1.884; P = .02), long duration of operation (WMD 0.73, 95% CI 0.21-1.24; P = .006), spine fusion (OR 1.54, 95% CI 1.31-1.82; P < .001), and blood transfusion (OR 2.31, 95% CI 1.73-3.07; P < .001), and the differences were statistically significant. However, there were no significant differences in body mass index, obesity, hypertension, coronary heart disease, spondylolisthesis, intraoperative blood loss, surgical procedures (anterior lumbar interbody fusion vs posterior intervertebral fusion /translaminar lumbar interbody fusion), or surgical site (lumbar vs thoracic) (all P > .05).

CONCLUSION

Based on our meta-analysis, we identified several important factors that increased the risk of VTE after spinal surgery. We hope our study provides assistance to spine surgeons so that they can adequately analyze and assess risk factors in patients and then develop preventive measures to reduce the incidence of VTE.

90-day Readmission Rates for Single Level Anterior Lumbosacral Interbody Fusion: A Nationwide Readmissions Database Analysis

STUDY DESIGN

Nationwide Readmissions Database Study.

OBJECTIVE

To investigate the patterns of readmissions and complications following hospitalization for elective single level anterior lumbobsacral interbody fusion.

SUMMARY OF BACKGROUND DATA

Lumbar interbody spine fusions for degenerative disease have increased annually in the United States, including associated hospital costs. Anterior lumbar interbody fusions (ALIFs) have become popularized secondary to higher rates of fusion compared with posterior procedures, and preservation of posterior elements. Prior national databases have sought to study readmission rates with some limitations due to older diagnosis and procedure codes. The newer 2016 International Classification of Diseases Tenth Revision, Clinical Modification (ICD-10 CM) includes more specification of the surgical site.

METHODS

We utilized the 2016 United States Nationwide Readmissions Database (NRD), this nationally representative, all-payer database that includes weighted probability sample of inpatient hospitalizations for all ages. We identified all adults (≥ 18 yrs) using the 2016 ICD-10 coding system who underwent elective primary L5-S1 ALIF and examined rates of readmissions within 90 days of discharge.

RESULTS

Between January and September 2016, a total of 7029 patients underwent elective stand-alone L5-S1 ALIF who were identified from NRD of whom 497 (7.07%) were readmitted within 90 days of their procedure. No differences in sex were appreciated. Medicare patients had statistically significant higher readmission rates (47.69%) among all payer types. With respect to intraoperative complications, vascular complications had statistically significant increased odds of readmission (OR, 3.225, 95% CI, 0.59 -1.75; P = 0.0001). Readmitted patients had higher total healthcare costs.

CONCLUSION

The 90-day readmission rate following stand-alone single level lumbosacral (L5-S1) ALIF was 7.07%. ALIF procedures have increased in frequency, and an understanding of the comorbidities, age-related demographics, and costs associated with 90-day readmissions are critical. Surgeons should consider these risk factors in preoperative planning and optimization.

LEVEL OF EVIDENCE

3.

Atrial Fibrillation and Bleeding in Patients With Chronic Lymphocytic Leukemia Treated with Ibrutinib in the Veterans Health Administration

BACKGROUND

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults. The introduction of novel oral agents, starting with ibrutinib in 2013, has revolutionized the therapeutic landscape; however, clinical trials have suggested an association between ibrutinib and the risk of bleeding-related adverse events and atrial fibrillation (Afib) in patients with CLL.

METHODS

Patients diagnosed and treated for CLL at the Veterans Health Administration (VHA) from 2010 to 2014 were followed until December 31, 2016, death, or lack of utilization of hematology/oncology services for ≥ 18 months; or until incidence of another cancer. Treatments dispensed, evidence of VHA system use, bleeding events, and Afib were determined from the administrative records, laboratory records, pharmacy dispensation records, and clinical notes in the electronic healthcare record.

RESULTS

From 2010 to 2014, 2,796 patients were diagnosed and received care for CLL within the VHA, of whom 172 patients received ibrutinib and 291 received bendamustine + rituximab (BR). The use of anticoagulants following induction therapy did not differ between BR and ibrutinib patients (9% vs 8%, respectively), nor did the use of antiplatelets agents (6% vs 2%, respectively). Of the 291 patients that received BR, 12 (4%) developed a bleeding event compared with 20 (12%) who received ibrutinib. Additionally, 13 (8%) ibrutinib patients developed Afib compared with 9 (3%) BR patients.

CONCLUSIONS

Real-world evidence from a nationwide cohort of patients with CLL suggests that while ibrutinib is associated with increased bleeding-related adverse events and Afib, the risk is comparable to those reported in previous clinical trials. These findings suggest that patients in real-world clinical care settings with higher levels of comorbidities may be at an increased risk for bleeding events and Afib.

Do Clinical Outcomes and Sagittal Parameters Differ Between Diabetics and Nondiabetics for Degenerative Spondylolisthesis Undergoing Lumbar Fusion?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To assess the effect of diabetes mellitus (DM) on clinical and radiographic outcomes in patient with degenerative spondylolisthesis undergoing posterior lumbar spinal fusion.

METHODS

Analysis of patients who underwent open posterior lumbar spinal fusion from 2011 to 2018. Patients being medically treated for DM were identified and separated from nondiabetic patients. Visual analogue scale Back/Leg pain and Oswestry Disability Index (ODI) were collected, and achievement of minimal clinically important difference was evaluated. Lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and PI-LL difference were measured on radiographs. Rates of postoperative complications were also collected.

RESULTS

A total of 850 patients were included; 78 (9.20%) diabetic patients and 772 (90.80%) nondiabetic patients. Final PI-LL difference was significantly larger (P = .032) for patients with diabetes compared to no diabetes, but there were no other significant differences between radiographic measurements, operative time, or postoperative length of stay. There were no differences in clinical outcomes between the 2 groups. Diabetic patients were found to have a higher rate of discharge to a facility following surgery (P = .018). No differences were observed in reoperation or postoperative complication.

CONCLUSIONS

While diabetic patients had more associated comorbidities compared with nondiabetic patients, they had similar patient-reported and radiographic outcomes. Similarly, there are no differences in rates of reoperation or postoperative complications. This study indicates that diabetic patients who have undergone thorough preoperative screening of related comorbidities and appropriate selection should be considered for lumbar spinal fusion.

Risk Factors for Medical and Surgical Complications After Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion

Background

The prevention of perioperative and postoperative complications is necessary to avoid poor postoperative outcomes and increased costs. Previous investigations have identified risk factors for complications after various spine procedures, but no such study exists in a population solely undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). The purpose of this study is to determine risk factors for the development of complications up to 2 years after MIS TLIF procedures.

Methods

Patients who underwent primary, single-level MIS TLIF from 2007 to 2016 were retrospectively reviewed. The incidence of medical and surgical complications up to 2 years postoperatively was determined. Patients were categorized according to demographic, comorbidity, and procedural characteristics. Bivariate Poisson regression with robust error variance was used to determine if an association existed between patient characteristics and complication incidence. A final multivariate model including all patient characteristics as controls was created using backwards, stepwise regression until only those variables with P < .05 remained.

Results

390 patients were analyzed. Upon bivariate analysis, age >50 years (P = .025), diabetes mellitus (P = .001), and operative duration >105 minutes (P = .016) were associated with increased medical complication rates. Regarding surgical complications, age ≤50 years (P < .001), obesity (P = .012), and diabetes mellitus (P = .042) were identified as risk factors on bivariate analysis. Upon final multivariate analysis, operative time >105 minutes (P = .009) and diabetes mellitus (P = .001) were independent risk factors for medical complications. Independent risk factors for surgical complications on multivariate analysis included age ≤50 years (P < .001), diabetes mellitus (P = .002), and obesity (P = .030).

Conclusions

Diabetic patients and those who underwent longer operations were at increased risk of medical complications, while younger patients, obese patients and those also with diabetes mellitus were at increased risk of surgical complications up to 2 years after MIS TLIF. Practitioners can use this information to identify patients who require preventative care before their procedure or increased postoperative vigilance and monitoring after single-level MIS TLIF.

Level of Evidence

3.

Can a machine learning model accurately predict patient resource utilization following lumbar spinal fusion?

BACKGROUND CONTEXT

With the increasing emphasis on value-based healthcare in Centers for Medicare and Medicaid Services reimbursement structures, bundled payment models have been adopted for many orthopedic procedures. Immense variability of patients across hospitals and providers makes these models potentially less viable in spine surgery. Machine-learning models have been shown reliable at predicting patient-specific outcomes following lumbar spine surgery and could, therefore, be applied to developing stratified bundled payment schemes.

PURPOSE

(1) Can a Naïve Bayes machine-learning model accurately predict inpatient payments, length of stay (LOS), and discharge disposition, following dorsal and lumbar fusion? (2) Can such a model then be used to develop a risk-stratified payment scheme?

STUDY DESIGN

A Naïve Bayes machine-learning model was constructed using an administrative database.

PATIENT SAMPLE

Patients undergoing dorsal and lumbar fusion for nondeformity indications from 2009 through 2016 were included. Preoperative inputs included age group, gender, ethnicity, race, type of admission, All Patients Refined (APR) risk of mortality, APR severity of illness, and Clinical Classifications Software diagnosis code.

OUTCOME MEASURES

Predicted resource utilization outcomes included LOS, discharge disposition, and total inpatient payments. Model validation was addressed via reliability, model output quality, and decision speed, based on application of training and validation sets. Risk-stratified payment models were developed according to APR risk of mortality and severity of illness.

RESULTS

A Naïve Bayes machine-learning algorithm with adaptive boosting demonstrated high reliability and area under the receiver-operating characteristics curve of 0.880, 0.941, and 0.906 for cost, LOS, and discharge disposition, respectively. Patients with increased risk of mortality or severity of illness incurred costs resulting in greater inpatient payments in a patient-specific tiered bundled payment, reflecting increased risk on institutions caring for these patients. We found that a large range in expected payments due to individuals' preoperative comorbidities indicating an individualized risk-based model is warranted.

CONCLUSIONS

A Naïve Bayes machine-learning model was shown to have good-to-excellent reliability and responsiveness for cost, LOS, and discharge disposition. Based on APR risk of mortality and APR severity of illness, there was a significant difference in episode costs from lowest to highest risk strata. After using normalized model error to develop a risk-adjusted proposed payment plan, it was found that institutions incur significantly more financial risk in flat bundled payment models for patients with higher rates of comorbidities.