Risk factors for distal junctional failure in long-construct instrumentation for adult spinal deformity.

PURPOSE: The aim of this study is to identify risk factors associated with postoperative DJF in long constructs for ASD. METHODS: A retrospective review was performed at a tertiary referral spine centre from 01/01/2007 to 31/12/2016. Demographic, clinical and radiographic parameters were collated for patients with DJF in the postoperative period and compared to those without DJF. Survival analyses were performed using univariate logistic regression to identify variables with a p value < 0.05 for inclusion in multivariate analysis. Spearman's correlations were performed where applicable. RESULTS: One hundred two patients were identified. 41 (40.2%) suffered DJF in the postoperative period, with rod fracture being the most common sign of DJF (13/65; 20.0%). Mean time to failure was 32.4 months. On univariate analysis, pedicle subtraction osteotomy (p = 0.03), transforaminal lumbar interbody fusion (p < 0.001), pre-op LL (p < 0.01), pre-op SVA (p < 0.01), pre-op SS (p = 0.02), postop LL (p = 0.03), postop SVA (p = 0.01), postop PI/LL (p < 0.001), LL correction (p < 0.001), SVA correction (p < 0.001), PT correction (p = 0.03), PI/LL correction (p < 0.001), SS correction (p = 0.03) all proved significant. On multivariate analysis, pedicle subtraction osteotomy (OR 27.3; p = 0.03), postop SVA (p < 0.01) and LL correction (p = 0.02) remained statistically significant as independent risk factors for DJF. CONCLUSION: Recently, DJF has received recognition as its own entity due to a notable postoperative incidence. Few studies to date have evaluated risk factors for DJF. The results of our study highlight that pedicle subtraction osteotomy, poor correction of lumbar lordosis, and sagittal vertical axis are significantly associated with postoperative occurrence of DJF.

Surgical Decision Making for Thoracolumbar Spine Injuries in Polytrauma Patients.

The management of thoracolumbar spine injuries in patients with multiple traumatic injuries is a challenge complicated by multiple competing medical and surgical demands. Safe and effective treatment of polytrauma patients with a thoracolumbar spine injury requires a multidisciplinary approach that involves surgical and critical care teams. The Thoracolumbar Injury Classification and Severity Score, which was developed to facilitate consistent surgical decision making in patients with a thoracolumbar spine injury, provides objective criteria for the classification and management of thoracolumbar spine injuries. The AOSpine study group recently developed a comprehensive thoracolumbar injury classification system that was subsequently used to create the Thoracolumbar AOSpine Injury Score, which helps guide thoracolumbar spine injury management via objective criteria. These scoring systems have been effectively used in clinical practice and allow for a focused and objective assessment of thoracolumbar spine injuries. Both the Thoracolumbar Injury Classification and Severity Score and the Thoracolumbar AOSpine Injury Score should be routinely used in treatment decision making to optimize outcomes and avoid unnecessary surgical treatment in polytrauma patients with a thoracolumbar spine injury.

Fracture Risk in Ulnohumeral Arthroplasty-A Biomechanical Study.

PURPOSE: Ulnohumeral arthroplasty, also known as the Outerbridge-Kashiwagi procedure, was popularized after reports of successful results in 1978, and has long been a means of management for ulnohumeral arthritis. However, there are concerns over the loss of integrity of the distal humerus as a result of fenestration. The purpose of this study was to examine the relationship between the size of fenestration and fracture risk. METHODS: Using a validated fourth-generation sawbones model, load to failure and site of fracture were investigated following incrementally increasing distal humeral fenestration sizes. Each sample was subjected to a uniform extension stress on a materials testing system, with 5 samples run for each group. The experimental groups began with a fenestration size of 10 mm and increased by 3 mm increments up to 31 mm. Load at failure and site of fracture were recorded for each sample. RESULTS: Forty-five fourth-generation sawbones samples were tested. Average load at sample failure was equivalent for each fenestration group up to 25 mm. At 28 mm, average load to failure began to decrease, and was statistically significant beginning between 28 mm and 31 mm. At 28 mm, 4 of 5 samples fractured through the fenestration, and at 31 mm, all 5 samples fractured through the fenestration. This change in fracture site became statistically significant between 25 mm and 28 mm. CONCLUSIONS: Distal humeral fenestration does compromise its structural integrity; however, for resection in the range of 10-25 mm, there is no increased risk of fracture. CLINICAL RELEVANCE: On the basis of this biomechanical model, the authors do not recommend any activity limitations after initial surgical recovery, but do recommend against distal humeral fenestrations larger than 25 mm when performing this procedure.

Cervical Disc Displacement in Military Pilots.

INTRODUCTION: Cervical disc displacement (CDD) may disqualify pilots from flying and have a profound impact on military unit capability. The objective of this retrospective database review is to characterize the incidence and demographic predictors of symptomatic cervical spine disc displacement in pilots of fixed- and rotary-wing aircraft and ground-based controls. MATERIALS AND METHODS: The Defense Military Epidemiology Database was queried for first-occurrence ICD-9 code 722.0: CDD cases from 2007 to 2015. Injury count rates among aircraft groups and overall incidence per 1,000 person-years were calculated and standardized for age, gender, and military rank, and 95% confidence intervals (CIs) were compared to determine significance. RESULTS: There were 934 new cases of CDD among active duty U.S. Military pilots during the study period. The overall incidence of CDD in all pilots during this time frame was 2.715 per 1,000 person-years (95% CI, 2.603-2.830). Helicopter pilots had a significantly higher incidence compared to all other aircraft pilots and crew at 3.79 per 1,000 person-years (95% CI, 3.48-4.13). This finding remained statistically significant after standardizing for age, gender, and rank. Among all military officers, increasing age was a risk factor for CDD. CONCLUSIONS: The U.S. Military helicopter pilots have an increased risk compared to fixed-wing pilots and non-pilot controls. CDD remains a rare, though career-threatening, condition. Increased education and awareness training are warranted for both helicopter pilots and flight physicians to recognize signs and symptoms of cervical pathology. Continued investigations into preventive measures to minimize injury and time unfit for flight are warranted.

Indicators for Substantial Neurological Recovery Following Elective Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The purposes of this study were to determine the rate of improvement of significant preoperative weakness, identify risk factors for failure to improve, and characterize the motor recovery of individual motor groups. SUMMARY OF BACKGROUND DATA: While neck and arm pain reliably improve following anterior cervical discectomy and fusion (ACDF), the frequency and magnitude of motor recovery following ACDF remain unclear. METHODS: We performed a retrospective review of patients undergoing 1-4-level ACDF at a single institution between September 2015 and June 2016. Patients were subdivided into 2 groups based upon the presence or absence of significant preoperative weakness, which was defined as a motor grade <4 in any single upper extremity muscle group. Clinical notes were reviewed to determine affected muscle groups, rates of motor recovery, and risk factors for failure to improve. RESULTS: We identified 618 patients for inclusion. Significant preoperative upper extremity weakness was present in 27 patients (4.4%). Postoperatively, 19 of the affected patients (70.3%) experienced complete strength recovery, and 5 patients (18.5%) experienced an improvement in muscle strength to a motor grade ≥4. The rate of motor recovery postoperatively was 85.7% in the triceps, 83.3% in the finger flexors, 83.3% in the hand intrinsics, 50.0% in the biceps, and 25.0% in the deltoids. Risk factors for failure to experience significant motor improvement were the presence of myelomalacia (odds ratio: 28.9, P <0.01) and the performance of >2 levels of ACDF (odds ratio: 10.1, P <0.01). CONCLUSIONS: Patients with substantial preoperative upper extremity weakness can expect high rates of motor recovery following ACDF, though patients with deltoid weakness, myelomalacia, and >2 levels of ACDF are less likely to experience significant motor improvement.

The Incidence, Risk Factors, and Complications Associated With Surgical Delay in Multilevel Fusion for Adult Spinal Deformity.

STUDY DESIGN: Retrospective database review. OBJECTIVES: The incidence and risk factors for surgical delay of multilevel spine fusion for adult spinal deformity (ASD), and the complications corresponding therewith, remain unknown. The objectives of this study are to assess the incidence and risk factors for unexpected delay of elective multilevel spinal fusions on the date of surgery as well as the postoperative complications associated with these delays. METHODS: We conducted a retrospective review of the ACS-NSQIP database on patients undergoing elective spinal instrumentation of greater than 7 levels for ASD between the years 2005 and 2015. Preoperative risk factors for delay and postoperative complications were compared between the cohorts of patients with and without surgical delays. RESULTS: Multivariate analysis of 1570 (15.6%) patients identified advanced age, male sex, American Society of Anesthesiologists (ASA) Class 4, and history of smoking as independent risk factors for delay. Patients experiencing surgical delay demonstrated longer operative times, increased intraoperative bleeding, longer hospitalizations, and significantly higher rates of postoperative complications. Patients experiencing delay demonstrated an almost 7-fold increase in mortality rate (3.4% vs 0.5%, P < .001). CONCLUSIONS: Delays in elective surgical care for spinal deformity are negatively related to patient outcomes. Advanced age, male sex, increased ASA class, and a history of smoking cigarettes place patients at risk for surgical delay of multilevel spinal fusion. Patients experiencing surgical delay are at higher risk for postoperative complications, including a 7-fold increase in mortality. These findings suggest that ASD surgery should be postponed in patients experiencing a delay, until modifiable risk factors can be medically optimized, and perhaps postponed indefinitely in those with nonmodifiable risk factors.

A Systematic Review of Risk Factors Associated With Distal Junctional Failure in Adult Spinal Deformity Surgery.

BACKGROUND: The surgical management of adult spinal deformity (ASD) is a major surgical undertaking associated with considerable perioperative risk and a substantial complication profile. Although the natural history and risk factors associated with proximal junctional kyphosis (PJK) and proximal junctional failure are widely reported, distal junctional failure (DJF) is less well understood. STUDY DESIGN: A systematic review was carried out. OBJECTIVES: The primary objective is to identify the risk factors associated with DJF. The secondary objective is to delineate the incidence rate and causative factors associated with DJF. METHODS: A systematic review of articles in Medline/PubMed and The Cochrane Library databases was performed according to preferred reporting items for systematic reviews and meta-analyses guidelines. Data was collated to determine the prevalence of DJF and overall revision rates, and identify potential risk factors for development of DJF. RESULTS: Twelve studies were included for systematic review. There were 81/2261 (3.6%) cases of DJF. Overall, DJF represented 27.3% of all revision surgeries. Anterior-posterior surgery had a reduced incidence of postoperative DJF [5.0% vs. 8.7%; P=0.08; relative risk (RR)=1.73], as did patients below 60 years of age at the time of surgery (2.9% vs. 3.9%; P=0.09; RR=1.34). There was a higher incidence of DJF among those patients who received interbody fusion (9.9% vs. 5.1%; P=0.06; RR=1.93) compared with those who did not. However, none of these findings reached statistical significance. There were significantly more rates of DJF for fusions ending on L5 compared with constructs fused to the sacrum (11.7% vs. 3.6%; P=0.02; RR=3.28). CONCLUSIONS: Cohorts 60 years and above of age at the time of surgery and patients managed with posterior-only fusion or interbody fusion have increased incidences of DJF. Fusion to L5 instead of the sacrum significantly influences DJF rates. However, the quality of available evidence is low and further high-quality studies are required to more robustly analyze the clinical, radiographic, and surgical risk factors associated with the development of DJF after ASD surgery.

Regenerative Medicine Modalities for the Treatment of Degenerative Disk Disease.

Degenerative disk disease is a pathologic state associated with axial skeletal pain, radiculopathy, and myelopathy, and will inevitably increase in prevalence in parallel with an aging population. The objective of regenerative medicine is to convert the inflammatory, catabolic microenvironment of degenerative disease into an anti-inflammatory, anabolic environment. This comprehensive review discusses and outlines both in vitro and in vivo efficacy of regenerative treatment modalities for degenerative disk disease, such as; mesenchymal stem cells, gene therapy, tissue engineering, and biologic treatments. To date, clinical applications have been limited secondary to a lack of standardized high quality clinical data. Additional research should focus on determining the optimal cellular makeup and concentration for each of these interventions. Nevertheless, modern medicine provides a new avenue of confronting disease, with methods surpassing traditional methods of removing the pathology in question, as regenerative medicine provides the opportunity to recover from the diseased state.

Radiographic Measures of Spinal Alignment Are Not Predictive of the Development of C5 Palsy Following Anterior Cervical Discectomy and Fusion Surgery.

BACKGROUND: Postoperative C5 palsy is a common complication following cervical decompression, occurring more frequently after posterior-based procedures. It has been theorized that this is the result of C5 nerve stretch resulting from spinal cord drift with these procedures. As such, it is thought to be less common after anterior cervical decompression and fusion (ACDF). However, no consensus has been reached on its true etiology. The purpose of this study is to assess the rate of C5 palsy following ACDF and to determine whether any radiographic or demographic parameters were predictive of its development. METHODS: Two hundred and twenty-six patients who received ACDF between September 2015 and September 2016 were reviewed, and 122 were included in the final analysis. Patient demographic, surgical, and radiographic data were analyzed, including preoperative and postoperative radiographic and motor examination results. The Mann-Whitney U test was used to compare continuous variables between independent groups, and Fisher's exact test was used to compare categorical variables between groups. RESULTS: Seven patients developed a C5 palsy in the postoperative period, an incidence rate of 5.7%. Among the radiographic parameters evaluated, there were no statistically significant differences between the C5 palsy and nonpalsy groups. Additionally, there were no statistically significant differences in age, patient sex, or numbers of vertebral levels fused between groups. CONCLUSIONS: Ultimately, we did not identify any statistically significant demographic or radiographic predictive factors for the development of C5 palsy following ACDF surgery. LEVEL OF EVIDENCE: 3.

Surgical Management of Thoracolumbar Burst Fractures: Surgical Decision-making Using the AOSpine Thoracolumbar Injury Classification Score and Thoracolumbar Injury Classification and Severity Score.

The management of thoracolumbar burst fractures is controversial with no universally accepted treatment algorithm. Several classification and scoring systems have been developed to assist in surgical decision-making. The most widely accepted are the Thoracolumbar Injury Classification and Severity Score (TLICS) and AOSpine Thoracolumbar Injury Classification Score (TL AOSIS) with both systems designed to provide a simple objective scoring criteria to guide the surgical or nonsurgical management of complex injury patterns. When used in the evaluation and treatment of thoracolumbar burst fractures, both of these systems result in safe and consistent patient care. However, there are important differences between the 2 systems, specifically in the evaluation of the complete burst fractures (AOSIS A4) and patients with transient neurological deficits (AOSIS N1). In these circumstances, the AOSpine system may more accurately capture and characterize injury severity, providing the most refined guidance for optimal treatment. With respect to surgical approach, these systems provide a framework for decision-making based on patient neurology and the status of the posterior tension band. Here we propose an operative treatment algorithm based on these fracture characteristics as well as the level of injury.

Spinopelvic Dissociation: Assessment, Reduction Strategies, and Fixation Techniques.

Spinopelvic dissociation is a rare injury associated with 2% to 3% of transverse sacral fractures and 3% of sacral fractures associated with pelvic ring injuries. When spinopelvic dissociation is expediently identified and treated appropriately, patient outcomes can be maximized, highlighting the importance of early diagnosis and treatment. Because of its rarity and complexity, there remains a paucity of high-level evidence-based guidance on treating this complex issue. No consensus exists on fixation techniques or reduction maneuvers to achieve stability, allowing for early functional rehabilitation. The purpose of this article is to review the current body of literature to better understand this injury pattern to help establish a treatment algorithm that appropriately guides the treating surgeons in the surgical planning and perioperative care of these patients.

A Comparison of Revision Rates and Patient-Reported Outcomes for a 2-Level Posterolateral Fusion Augmented With Single Versus 2-Level Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective, single institution, multisurgeon case control series. OBJECTIVE: To determine whether there are differences in reoperation rates or outcomes for patients undergoing 2-level posterolateral fusion (PLF) augmented by a transforaminal lumbar interbody fusion (TLIF) at only one of the levels or at both. METHODS: A total of 416 patients were identified who underwent 2-level PLF with a TLIF at either one of those levels (n = 183) or at both (n = 233) with greater than 1-year follow-up. Demographic, surgical, radiographic, and clinical data was reviewed for each patient. These included age, sex, race, body mass index, smoking status, Charleston Comorbidity Index, operative time, estimated blood loss, length of stay, and patient-reported outcome measures. RESULTS: Each cohort underwent 24 reoperations. Although the number of overall reoperations was not significantly different (P > .05), among the reoperation types, there were significantly more reoperations for adjacent segment disease in the 2-level group compared to the 1-level group (19 vs 12, P = .04). There was no difference in reoperation for pseudarthrosis between the groups (P > .05). Although both groups experienced significant improvements in Oswestry Disability Index (P < .001) and Short Form-12 health questionnaire (P < .001), there were no differences between improvements for 1- versus 2-level cohorts. CONCLUSIONS: For patients undergoing 2-level PLF in the setting of a TLIF, using a TLIF at one versus both levels does not seem to influence reoperation rates or outcomes. However, reoperation rates for adjacent segment disease are increased in the setting of a 2-level PLF augmented by a 2-level TLIF.

Percutaneous Pedicle Screws in the Obese: Should the Skin Incision Be More Lateral?

OBJECTIVE: To determine if the skin incision for lumbar percutaneous pedicle screws should be more lateral in the obese patient. METHODS: This was a retrospective radiographic analysis of 30 obese and non-obese lumbar spine computed tomography (CT) radiographs comparing the depth of soft tissue along the anatomic axis of the pedicle at L4 and L5. RESULTS: The average distance from the pedicle trajectory on the skin to the lateral border of the pedicle at L4 was 1.4 cm and 3.8 cm in the non-obese and obese groups, respectively. The average distance from the pedicle trajectory on the skin to the lateral border of the pedicle at L5 was 2.1 cm and 4.3 cm in the non-obese and obese groups, respectively; both these differences reached statistical significance, p <0.05. CONCLUSIONS: This radiographic study supports a more lateral start point for percutaneous pedicle screws in obese patients to maintain an anatomic trajectory when inserting percutaneous pedicle screws into the lumbar spine at L4 and L5. If a skin incision is made at only 1 cm lateral to the pedicle in the obese patient, the surgeon often has to place significant traction on the skin edge to lateralize their instrumentation to achieve an appropriate angle of insertion. By making a more lateral skin incision, less manipulation of the skin and soft tissues is needed to maintain an anatomic trajectory of the pedicle screw. Decreasing soft tissue manipulation may decrease wound and instrumentation complications in this at-risk population.

Surgical Strategies to Prevent Adjacent Segment Disease in the Cervical Spine.

The most popular approach to treating symptomatic cervical disk disease is anterior cervical discectomy and fusion. Although this procedure has significant long-term clinical success, it is associated with progressive adjacent segment degeneration with an annual incidence of ∼3%. Total disk arthroplasty was designed as an alternative to fusion that could preserve segmental motion at the operative level and potentially delay or prevent adjacent-level breakdown. The etiology of adjacent segment pathology (ASP) is multifactorial, and it is likely that most cases of ASP are unavoidable. When attempting to surgically prevent ASP, it is important to consider nonfusion alternatives, be judicious in one's level selection, and attempt to restore sagittal alignment. When ASP becomes a clinical problem, it is important to have an algorithm for how best to treat it.

C5 Motor Palsy After Single- and Multi-level Anterior Cervical Diskectomy and Fusion: A Retrospective Review.

INTRODUCTION: Postoperative C5 nerve root palsy is a known complication after cervical surgery. The effect of increasing number of levels fused on the prevalence of C5 palsy after anterior cervical diskectomy and fusion (ACDF) is unclear. METHODS: Medical records of ACDF patients that included the C4-5 level at one institution were retrospectively reviewed. C5 palsy was defined as motor decline of the deltoid and/or biceps brachii muscle function by at least 1 level on standard manual muscle testing. RESULTS: A total of 196 patients met the inclusion criteria, with no significant differences noted between groups undergoing single- or multi-level ACDF. The overall C5 palsy rate was 5.1%. Palsy rates were not statistically significant based on the number of levels fused. Six of the 10 patients with C5 palsy had complete recovery of motor strength, whereas 2 patients had at least some level of strength recovery. CONCLUSION: The overall C5 palsy rate was 5.1% for all patients undergoing up to four-level ACDF. The rate of postoperative motor decline was lowest in the patients undergoing two-level ACDF and highest in the single-level group, but this finding did not reach statistical significance. The prognosis for strength recovery by final follow-up is excellent. LEVEL OF EVIDENCE: Level III, Case-control.

Risk Factors for Adverse Cardiac Events After Lumbar Spine Fusion.

BACKGROUND: To determine the incidence and risk factors for adverse cardiac events after lumbar spine fusion. METHODS: A total of 50 495 patients were identified through the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database who underwent lumbar spine fusion between 2005 and 2015. The 30-day postoperative data were analyzed to assess for the incidence of adverse cardiac events including cardiac arrest or myocardial infarction. Of those who experienced an event, patient- and surgery-specific parameters were evaluated to assess for risk factors. RESULTS: A total of 240 cardiac events occurred in the studied cohort (4.76 events/1000 patients). Factors that were associated with an increased cardiac risk were age (odds ratio [OR] = 1.039, 95% confidence interval [CI] = 1.03, 1.05, P < .001), male sex (OR = 1.51, 95% CI = 1.17, 1.94, P = .001), insulin-dependent diabetes (OR = 1.83, 95% CI = 1.29, 2.6, P = .001), American Society of Anesthesiologists (ASA) score >3 (OR = 1.92, 95% CI = 1.00, 3.65, P = .048), absolute hematocrit different from 45 (OR = 1.07, 95% CI = 1.04, 1.10, P < .001), and smoking (OR = 1.39, 95% CI = 1.02, 1.90, P = .04). The impact of sustaining a cardiac event in the setting of single-level lumbar fusion is catastrophic as the 30-day postoperative mortality rate for those sustaining an event was 24.6% (59/240 patients), compared to 0.2% (87/50 255) for those not sustaining an event (P < .001). CONCLUSIONS: Cardiac events after lumbar fusion are a rare but devastating series of complications. Several risk factors were identified, including insulin-dependent diabetes mellitus, smoking, advanced age, male sex, ASA score of >3, and anemia/polycythemia. Considering the severity of these consequences, appropriate risk stratification is imperative, and optimization of modifiable risk factors may mitigate this risk.

Spine Registries: Where Do We Stand?

To curb the unsustainable rise in health care costs, novel payment models are being explored which focus on value rather than volume. Underlying this reform is an accurate understanding of costs and outcomes. The Patient Protection and Affordable Care Act, the Institute of Medicine, and the Agency for Healthcare Research and Quality have specifically advocated for the use of registries to help define the real-world effectiveness of surgical interventions to help guide health care reform. Registries can help define value by documenting surgical efficacy, and specifically by reporting patient-based outcome measures. Over the past 10 years, several spine registries have been initiated and some others have expanded. These are providing a repository of evidence for surgical value. Herein, we will review the components of a well-designed registry and provide examples of such registries and their impact on health care delivery.

Intraoperative pedicle screw navigation does not significantly affect complication rates after spine surgery.

Various forms of intraoperative computer-assisted navigation technologies exist, and have consistently been shown to improve pedicle screw accuracy. However, the overall clinical effects of inaccurate pedicle screw placement have been debated. We examined the clinical effects of improved pedicle screw accuracy with computer navigation technology in reducing complication rates in patients undergoing multi-level spinal fusion. We retrospectively reviewed the ACS-NSQIP registry utilizing Current Procedural Terminology (CPT) codes 22843 + 22844 to identify patients undergoing spinal instrumentation of greater than 7 levels, as well as the CPT code 61783 to denote the use of intraoperative computer-assisted navigation. The data were then subdivided to into cohorts consisting of instrumentation cases with and without navigation. Demographic information, as well as intraoperative and postoperative complications, were compared between groups. A total of 3168 patients met our inclusion criteria. There were no statistically significant differences in preoperative population data. Surgical time was significantly longer in the navigation group (391.41 versus 350.3 min), but there were no significant improvements in complication rates with the use of navigation. We found that the mean operative time was significantly increased for patients undergoing spinal instrumentation with computer navigation. This increase in operative time was not associated with any increase in surgical or medical complications. However, in this large series, we were unable to show any clinical benefit to intraoperative navigation, and no reductions in short term complications or rates of return to surgery were observed.

Risk Factors for and Complications After Surgical Delay in Elective Single-Level Lumbar Fusion.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To assess the incidence of and risk factors for delay of elective lumbar fusion surgery, as well as medical and surgical complications associated with surgical delay. SUMMARY OF BACKGROUND DATA: Lumbar fusion is a well-established treatment for patients with degenerative spondylolisthesis with stenosis who have failed conservative management. Rarely, patients admitted for elective lumbar fusion may experience a delay in surgery past the day of admission. The incidence of, and risk factors for, delay of elective lumbar fusion surgery and the complications associated therewith have never been previously evaluated. METHODS: We retrospectively reviewed the ACS-NSQIP registry utilizing Current Procedural Terminology (CPT) codes 22612, 22558, 22630, and 22633 to identify all patients undergoing a single level spinal fusion. The data were then subdivided into cohorts consisting of patients with and without surgical delay. Demographic information, preoperative risk factors for delay, as well as intraoperative and postoperative complications were compared between the groups. RESULTS: We identified 2758 (5.46%) patients as experiencing a delay before lumbar fusion. Multivariate analysis was then performed and identified male sex, American Society of Anesthesiologists classes 3 and 4, and chronic steroid use as risk factors increasing the rate of surgical delay. Multiple complication rates were also significantly higher in the delayed group, including an almost 10-fold increase in mortality rate (0.2% vs. 1.9%, respectively, P < 0.001). CONCLUSION: Delays in elective surgery can affect medical system resource utilization, increasing costs and leading to worse patient outcomes. Patients with chronic steroid use and higher American Society of Anesthesiologists class may be at risk for surgical delay in lumbar fusion beyond the day of admission, and are at increased risk for significant complications postoperatively. Thorough medical evaluation and preoperative optimization may be indicated for these patients. LEVEL OF EVIDENCE: 4.

Severe Lumbar Disability Is Associated With Decreased Psoas Cross-Sectional Area in Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective cohort. OBJECTIVES: Alterations in lumbar paraspinal muscle cross-sectional area (CSA) may correlate with lumbar pathology. The purpose of this study was to compare paraspinal CSA in patients with degenerative spondylolisthesis and severe lumbar disability to those with mild or moderate lumbar disability, as determined by the Oswestry Disability Index (ODI). METHODS: We retrospectively reviewed the medical records of 101 patients undergoing lumbar fusion for degenerative spondylolisthesis. Patients were divided into ODI score ≤40 (mild/moderate disability, MMD) and ODI score >40 (severe disability, SD) groups. The total CSA of the psoas and paraspinal muscles were measured on preoperative magnetic resonance imaging (MRI). RESULTS: There were 37 patients in the SD group and 64 in the MMD group. Average age and body mass index were similar between groups. For the paraspinal muscles, we were unable to demonstrate any significant differences in total CSA between the groups. Psoas muscle CSA was significantly decreased in the SD group compared with the MMD group (1010.08 vs 1178.6 mm2, P = .041). Multivariate analysis found that psoas CSA in the upper quartile was significantly protective against severe disability (P = .013). CONCLUSIONS: We found that patients with severe lumbar disability had no significant differences in posterior lumbar paraspinal CSA when compared with those with mild/moderate disability. However, severely disabled patients had significantly decreased psoas CSA, and larger psoas CSA was strongly protective against severe disability, suggestive of a potential association with psoas atrophy and worsening severity of lumbar pathology.