Preoperative cross-sectional area of psoas muscle correlates with short-term functional outcomes after posterior lumbar surgery.

PURPOSE: To determine the optimal level for the measurement of psoas cross-sectional area and examine the correlation with short-term functional outcomes of posterior lumbar surgery. METHODS: Patients who underwent minimally invasive posterior lumbar surgery were included in this study. The cross-sectional area of psoas muscle was measured at each intervertebral level on T2-weighted axial images of preoperative MRI. Normalized total psoas area (NTPA) (mm2/m2) was calculated as total psoas area normalized to patient height. Intraclass Correlation Coefficient (ICC) was calculated for the analysis of inter-rater reliability. Patient reported outcome measures including Oswestry disability index (ODI), visual analog scale (VAS), short form health survey (SF-12) and patient-reported outcomes measurement information system were collected. A multivariate analysis was performed to elucidate independent predictors associated with failure to reach minimal clinically important difference (MCID) in each functional outcome at 6 months. RESULTS: The total of 212 patients were included in this study. ICC was highest at L3/4 [0.992 (95% CI: 0.987-0.994)] compared to the other levels [L1/2 0.983 (0.973-0.989), L2/3 0.991 (0.986-0.994), L4/5 0.928 (0.893-0.952)]. Postoperative PROMs were significantly worse in patients with low NTPA. Low NTPA was an independent predictor of failure to reach MCID in ODI (OR = 2.68; 95% CI: 1.26-5.67; p = 0.010) and VAS leg (OR = 2.43; 95% CI: 1.13-5.20; p = 0.022). CONCLUSION: Decreased psoas cross-sectional area on preoperative MRI correlated with functional outcomes after posterior lumbar surgery. NTPA was highly reliable, especially at L3/4.

The association between spondylolisthesis and decreased muscle health throughout the lumbar spine for patients with operative lumbar spinal stenosis.

PURPOSE: There are data underlining the relationship between muscle health and spine related pathology, but little data regarding changes in paralumbar muscle associated with lumbar spondylolisthesis. We aimed to define changes in paralumbar muscle health associated with spondylolisthesis. METHODS: A retrospective review was performed on consecutive patients with lumbar spine pathology requiring an operation. A pre-operative lumbar MRI was analysed for muscle health measurements including lumbar indentation value (LIV), paralumbar cross-sectional area divided by body mass index (PL-CSA/BMI), and Goutallier classification of fatty atrophy. All measurements were taken from an axial slice of a T2-weighted image at lumbar disc spaces. Baseline health-related quality of life scores (HRQOLs), narcotic use and areas of stenosis were tracked. We performed Chi-square analyses and student's t test to determine statistically significant differences between cohorts. RESULTS: There were 307 patients (average age 56.1 ± 16.7 years, 141 females) included within our analysis. 112 patients had spondylolisthesis. There were no differences in baseline HRQOLs between the spondylolisthesis cohort (SC) and non-spondylolisthesis cohort (non-SC). There were significantly worse PL-CSA/BMI at L2-L3 (p = 0.03), L3-L4 (p = 0.04) and L4-L5 (p = 0.02) for the SC. Goutallier classification of paralumbar muscle was worse for SC at L1-L2 (p = 0.04) and at L4-L5 (p < 0.001). Increased grade of spondylolisthesis was associated with worse PL-CSA at L1-L2 (p = 0.02), L2-L3 (p = 0.03) and L3-L4 (p = 0.05). Similarly, there were worse Goutallier classification scores associated with higher-grade spondylolisthesis at all levels (p < 0.05). CONCLUSION: There are significant detrimental changes to paralumbar muscle health throughout the lumbar spine associated with spondylolisthesis.

Predictors of discharge to an inpatient rehabilitation facility after a single-level posterior spinal fusion procedure.

PURPOSE: To determine perioperative characteristics of patients undergoing single-level spinal fusion surgery that could help predict discharge to an inpatient rehabilitation facility (IRF). METHODS: Demographic, peri- and postoperative characteristics were reviewed for 107 patients who underwent single-level spinal fusion surgery at a high-volume level I trauma center between January 2011 and December 2013. The relationships between discharge to IRF and gender, age, body mass index (BMI), Charlson Comorbidity Index (CCI), insurance provider, length of stay (LOS), intra- and postoperative outcomes and readmission rates in patients undergoing single-level spinal fusion surgery were analyzed using unpaired and paired t testing. RESULTS: 21.5 % (n = 23) of patients were discharged to an IRF. By using unpaired and paired t tests, it was determined that age, BMI, CCI, LOS and insurance provider were all correlated with a higher probability of being discharged to an IRF. Additionally, a logistic regression model demonstrated a correlation between lower CCI and discharge to an IRF. CONCLUSIONS: Statistically significant differences were seen regarding age, BMI, CCI, LOS and insurance provider when determining the necessity of a patient being discharged to an IRF. These characteristics can be used to begin the process of setting up discharge disposition preoperatively rather than postoperatively. There were no perioperative characteristics that were statistically significant in determining discharge disposition; therefore, physicians can utilize these preoperative demographics in deciding and organizing discharge before the day of surgery, which can diminish LOS and lead to substantial health system savings.

What is the Rate of Revision Discectomies After Primary Discectomy on a National Scale?

BACKGROUND: Lumbar discectomy has been shown to be clinically beneficial in numerous studies for appropriately selected patients. Some patients, however, undergo revision discectomy, with previously reported estimates of revisions ranging from 5.1% to 7.9%. No study to date has been able to precisely quantify the rate of revision surgery over numerous years on a national scale. QUESTIONS/PURPOSE: We performed a survival analysis for lumbar discectomy on a national scale using a life-table analysis to answer the following questions: (1) What is the rate of revision discectomy on a national scale over 5 to 7 years for patients undergoing primary discectomy alone? (2) Are there differences in revision discectomy rates based on age of patient, region of the country, or the payer type? METHODS: The Medicare 5% National Sample Administrative Database (SAF5) and a large national database from Humana Inc (HORTHO) were used to catalog the number of patients undergoing a lumbar discectomy. Both of these databases have been cited in numerous peer-reviewed publications during the previous 5 years and routinely are audited by PearlDiver Inc. We identified patients using relevant ICD-9 codes and Current Procedural Terminology (CPT) codes, including ICD-9 72210 (lumbar disc displacement) for disc herniation. We used appropriate CPT codes to identify patients who had a lumbar discectomy. We analyzed patients undergoing additional surgery including those who had repeat discectomy (CPT-63042: laminotomy, reexploration single interspace, lumbar) and patients who had additional more-extensive decompressive procedures with or without fusion after their primary procedure. Revision surgery rates were calculated for patients 65 years and older and those younger than 65 years and for each database (Humana Inc and Medicare). Patients from the two databases also were analyzed based on four distinct geographic regions in the United States where their surgery occurred. There were a total of 7520 patients who underwent a lumbar discectomy for an intervertebral disc displacement with at least 5 years of followup in the HORTHO and SAF5 databases. We used cumulative incidence of revision surgery to estimate the survivorship of these patients. RESULTS: In the HORTHO (2613 patients) and SAF5 (4907 patients) databases, 147 patients (5.6%; 95% CI, 1.8%-9.2%) and 305 patients (6.2%; 95% CI, 3.5%-8.9%) had revision surgery at 7 years after the index discectomy respectively. Survival analysis showed survival rates greater than 93% (95% CI, 91%-98%) for all of the cohorts for a primary discectomy up to 7 years after the surgery. The survivorship was lower for patients younger than 65 years (93% [95% CI, 87%-99%, 1016 of 1091] versus 95% [95% CI, 90%-100%, 1450 of 1522], p = 0.02). When nondiscectomy lumbar surgeries were included, the survivorship of patients younger than 65 years remained lower (83% [95% CI, 76%-89%, 902 of 1091] versus 87% [95% CI, 82%-92%, 1324 of 1522], p = 0.02). There was no difference in revision discectomy rates across geographic regions (p = 0.41) at 7 years. Similarly, there was no difference in additional nondiscectomy lumbar surgery rates (p = 0.68) across geographic regions at 7 years. There was no difference in survivorship rates between patients covered by Medicare (94% [95% CI, 91%-97%], 4602 of 4907) versus Humana Inc (94% [95% CI, 90%-98%], 2466 of 2613) (p = 0.31). CONCLUSIONS: Our study shows rates of cumulative survival after an index lumbar discectomy with revision discectomy as the endpoint. We hope these data allow physicians to offer accurate advice to patients regarding the risk of revision surgery for patients of all ages during 5 to 7 years after their index procedure to enhance shared decision making in spinal surgery. These data also will help public policymakers and accountable care organizations accurately allocate scarce resources to patients with symptomatic lumbar disc herniation. LEVEL OF EVIDENCE: Level III, therapeutic study.

The Cost Effectiveness of Polyetheretheketone (PEEK) Cages for Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Cost-effectiveness analysis using a Markov model with inputs from published literature. OBJECTIVE: To learn which graft or hardware option used in a single-level anterior cervical discectomy and fusion (ACDF) is most beneficial in terms of cost, quality of life, and overall cost effectiveness. Options studied were autograft, allograft, and polyetheretherketone (PEEK) cages for cervical fusion. SUMMARY OF BACKGROUND DATA: ACDF is commonly used to treat cervical myelopathy and/or radiculopathy. No study has compared the cost effectiveness of autograft, allograft, and PEEK in 1-level ACDF. MATERIALS AND METHODS: A literature review provided inputs into a Markov decision model to determine the most effective graft or hardware option for 1-level ACDF. Data regarding rate of complications, quality-adjusted life years (QALYs) gained, and cost for each procedure type was collected. The Markov model was first run in a base case, using all currently available data. The model was then tested using 1-way and 2-way sensitivity analyses to determine the validity of the model's conclusions if specific aspects of model were changed. This model was run for 10 years postoperatively. RESULTS: The cost per QALY for each option in the base case analysis was $3328/QALY for PEEK, $2492/QALY for autograft, and $2492/QALY for allograft. All graft/hardware options are cost effective ways to improve outcomes for patients living with chronic neck pain. For graft/hardware options the most cost-effective option was allograft. The incremental cost-effectiveness ratio for PEEK compared with autograft or allograft was >$100,000/QALY. CONCLUSIONS: Allograft is the most cost-effective graft/hardware option for ACDF. Compared with living with cervical myelopathy and/or radiculopathy, ACDF using any graft or hardware option is a cost-effective method of improving the quality of life of patients. PEEK is not a cost-effective option compared with allograft or autograft for use in ACDF.

Origin of the direct and reflected head of the rectus femoris: an anatomic study.

PURPOSE: This study aimed to define the footprint of the direct and reflected heads of the rectus femoris and the relation of the anterior inferior iliac spine (AIIS) to adjacent neurovascular (lateral circumflex femoral artery and femoral nerve), bony (anterior superior iliac spine [ASIS]), and tendinous structures (iliopsoas). METHODS: Twelve fresh-frozen cadaveric hip joints from 6 cadavers, average age of 44.5 (±9.9) years, were carefully dissected of skin and fascia to expose the muscular, capsular, and bony structures of the anterior hip and pelvis. Using digital calipers, measurements were taken of the footprint of the rectus femoris on the AIIS, superior-lateral acetabulum and hip capsule, and adjacent anatomic structures. RESULTS: The average dimensions of the footprint of the direct head of the rectus femoris were 13.4 mm (±1.7) × 26.0 mm (±4.1), whereas the dimensions of the reflected head footprint were 47.7 mm (±4.4) × 16.8 mm (±2.2). Important anatomic structures, including the femoral nerve, psoas tendon, and lateral circumflex femoral artery, were noted in proximity to the AIIS. The neurovascular structure closest to the AIIS was the femoral nerve (20.8 ± 3.4 mm). CONCLUSIONS: The rectus femoris direct and reflected heads originate over a broad area of the anterolateral pelvis and are in close proximity to critical neurovascular structures, and care must be taken to avoid them during hip arthroscopy. CLINICAL RELEVANCE: A thorough knowledge of the anatomy of the proximal rectus femoris is valuable for any surgical exposure of the anterior hip joint, particularly arthroscopic subspine decompression and open femoroacetabular impingement (FAI) surgery.

One-week staged bilateral total knee arthroplasty protocol: a safety comparison of intended and completed surgeries.

The number of patients requiring bilateral total knee arthroplasty (TKA) is expected to grow rapidly. While some trials have compared staged with simultaneous TKA, no literature characterizes the subset of staged TKA patients who cancel their second surgery. In this study, we report on the safety and utility of a one-week staged TKA protocol in a series of 145 patients who registered to undergo staged bilateral total knee arthroplasty one week apart. Among these patients, we identify a significantly higher complication rate and comorbidity status among patients who do not proceed to a second TKA. This finding identifies a potential advantage of a staged protocol over simultaneous bilateral TKA in not subjecting higher-risk patients to a second physiologic insult of a contralateral TKA.

A National Database Retrospective Review of Short-Term Postoperative Mortality in the Geriatric Population: A Comparison Between Emergency Spine Fractures and Hip Fractures.

BACKGROUND: Mortality rates following emergency spine fracture surgery are high, especially in the elderly. However, how the postoperative mortality rate following spine fractures compares to other geriatric fractures such as hip fractures remains unclear. Therefore, this retrospective cohort study aimed to compare 30-day mortality rates and risk factors between emergency spine fracture versus hip fracture surgery in the elderly. METHODS: The National Surgical Quality Improvement Program (NSQIP) database was queried between 2011 and 2021 for emergency spine fractures and hip fractures in the elderly. Univariate analyses evaluated demographic data, perioperative factors, comorbidities, and 30-day mortality rates as the primary outcomes. A multivariable regression model was then constructed to control for significant baseline and demographic differences and evaluate independent predictors of mortality. RESULTS: A total of 18,287 emergency hip fractures and 192 emergency spine fractures were included in our study. Univariate analysis demonstrated significant differences in female sex, body mass index (BMI), operation time, length of hospital stays, disseminated cancer, and functional dependence between spine and hip fractures. Thirty-day mortality rates were significantly higher in spine versus hip fractures (9.4% vs. 5%). Multivariate regression analysis demonstrated emergent spine fracture surgery, disseminated cancer, functional dependence, and length of stay as independent predictors of mortality in our cohort. Female sex, BMI, and operation time were protective factors for mortality in our cohort. CONCLUSIONS: Emergency spine fractures in the elderly represent an independent predictor for 30-day postoperative mortality compared to emergency hip fractures. Disseminated cancer, functional dependence, and length of stay were independent predictors of mortality while female sex, BMI, and operation time were protective factors. These data demonstrate the severity of injury and high rates of mortality that clinicians can use to counsel patients and their families.

Influence of Placement of Lumbar Interbody Cage on Subsidence Risk: Biomechanical Study.

OBJECTIVE: Lumbar spinal fusion is a common surgical procedure that can be done with a variety of different instrumentation and techniques. Despite numerous research studies investigating subsidence risk factors, the impact of cage placement on subsidence is not fully elucidated. This study aims to determine whether placement of an expandable transforaminal lumbar interbody fusion cage at the center end plate or at the anterior apophyseal ring affects cage subsidence. METHODS: A transforaminal lumbar interbody fusion cage was placed centrally or peripherally between 2 synthetic vertebral models of L3 and L4. A compression plate attached to a 10 KN load cell was used to uniaxially compress the assembly. The ultimate force required for the assembly to fail and subsidence stiffness were analyzed. Computed tomography scans of each L3 and L4 were obtained, and maximum end plate subsidence was measured in the frontal plane. RESULTS: Anterior apophyseal cage placement resulted in higher stiffness of the vertebrae-cage assembly (Ks, 962.89 N/mm) and a higher subsidence stiffness (Kb,987.21 N/mm) compared with central placement (P < 0.05). Ultimate compressive load of the vertebrae-cage assembly did not increase. Moreover, the maximum subsidence depth did not significantly vary between placements. CONCLUSIONS: The subsidence stiffness increased with anterior apophyseal cage placement. Periphery end plate cortical bone architecture may play a role in resisting the impact of cage subsidence. To fully understand the effect of cage placement on cage subsidence, future studies should investigate its implications on native and diseased spine.

Impact of the COVID-19 Pandemic on Outcomes and Perioperative Factors Associated with Posterior Cervical Fusion.

Introduction: While there is anecdotal evidence that the coronavirus disease 2019 (COVID-19) pandemic altered perioperative decision-making in patients requiring posterior cervical fusion (PCF), a national-level analysis to examine the significance of this hypothesis has not yet been conducted. This study aimed to determine the potential differences in perioperative variables and surgical outcomes of PCF performed before vs. during the COVID-19 pandemic. Methods: Adults who underwent PCF were identified in the 2019 (prepandemic) and 2020 (intrapandemic) NSQIP datasets. Differences in 30-day readmission, reoperation, and morbidity were evaluated using multivariate logistic regression. On the other hand, differences in operative time and relative value units (RVUs) were estimated using quantile regression. Furthermore, the odds ratios (OR) for length of stay (LOS) were estimated using negative binomial regression. Secondary outcomes included rates of nonhome discharge and outpatient surgery. Results: A total of 3,444 patients were included in this study (50.7% from 2020). Readmission, reoperation, morbidity, operative time, and RVUs per minute were similar between cohorts (p>0.05). The LOS (OR 1.086, p<0.001) and RVUs-per-case (coefficient +0.360, p=0.037) were significantly greater in 2020 compared to 2019. Operation year 2020 was also associated with lower rates of nonhome discharge (22.3% vs. 25.8%, p=0.017) and higher rates of outpatient surgery (4.8% vs. 3.0%, p=0.006). Conclusions: During the COVID-19 pandemic, a 28% decreased odds of nonhome discharge following PCF and a 72% increased odds of PCF being performed in an outpatient setting were observed. The readmission, reoperation, and morbidity rates remained unchanged during this period. This is notable given that patients in the 2020 group were more frail. This suggests that patients were shifted to outpatient centers possibly to make up for potentially reduced case volume, highlighting the potential to evaluate rehabilitation-discharge criteria. Further research should evaluate these findings in more detail and on a regional basis.

Comparison of Relative Value Units and 30-Day Outcomes Between Primary and Revision Pediatric Spinal Deformity Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to compare the relative value units (RVUs) and 30-day outcomes between primary and revision pediatric spinal deformity (PSD) surgery. SUMMARY OF BACKGROUND DATA: PSD surgery is frequently complicated by the need for reoperation. However, there is limited literature on physician reimbursement rates and short-term outcomes following primary versus revision spinal deformity surgery in the pediatric population. MATERIALS AND METHODS: This study utilizes data obtained from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) Pediatric database. Patients between 10 and 18 years of age who underwent posterior spinal deformity surgery between 2012 and 2018 were included. Univariate and multivariate regression were used to assess the independent impact of revision surgery on RVUs and postoperative outcomes, including 30-day readmission, reoperation, morbidity, and complications. RESULTS: The study cohort included a total of 15,055 patients, with 358 patients who underwent revision surgery. Patients in the revision group were more likely to be younger and male sex. Revision surgery more commonly required osteotomy (13.7% vs. 8.3%, P =0.002).Univariate analysis revealed higher total RVUs (71.09 vs. 60.51, P <0.001), RVUs per minute (0.27 vs. 0.23, P <0.001), readmission rate (6.7% vs. 4.0%, P =0.012), and reoperation rate (7.5% vs. 3.3%, P <0.001) for the revision surgery group. Morbidity rates were found to be statistically similar. In addition, deep surgical site infection, pulmonary embolism, and urinary tract infection were more common in the revision group. After controlling for baseline differences in multivariate regression, the differences in total RVUs, RVUs per minute, reoperation rate, and rate of pulmonary embolism between primary and revision surgery remained statistically significant. CONCLUSIONS: Revision PSD surgery was found to be assigned appropriately higher mean total RVUs and RVUs per minute corresponding to the higher operative complexity compared with primary surgery. Revision surgery was also associated with poorer 30-day outcomes, including higher frequencies of reoperation and pulmonary embolism. LEVEL OF EVIDENCE: Level III.

Cervical Paraspinal Muscle Fatty Infiltration is Directly Related to Extension Reserve in Patients With Cervical Spine Pathology.

STUDY DESIGN/SETTING: Retrospective review of a prospectively collected database. OBJECTIVE: The objective of this study was to determine the relationship between paracervical muscle area, density, and fat infiltration and cervical alignment among patients presenting with cervical spine pathology. BACKGROUND CONTEXT: The impact of cervical spine alignment on clinical outcomes has been extensively studied, but little is known about the association between spinal alignment and cervical paraspinal musculature. METHODS: We examined computed tomography scans and radiographs for patients presenting with cervical spine pathology. The posterior paracervical muscle area, density, and fat infiltration was calculated on axial slices at C2, C4, C6, and T1. We measured radiographic parameters including cervical sagittal vertical axis, cervical lordosis, T1 slope (T1S), range of motion of the cervical spine. We performed Pearson correlation tests to determine if there were significant relationships between muscle measurements and alignment parameters. RESULTS: The study included 51 patients. The paracervical muscle area was higher for males at C2 ( P =0.005), C4 ( P =0.001), and T1 ( P =0.002). There was a positive correlation between age and fat infiltration at C2, C4, C6, and T1 (all P <0.05). The cervical sagittal vertical axis positively correlated with muscle cross-sectional area at C2 ( P =0.013) and C4 ( P =0.013). Overall cervical range of motion directly correlated with muscle density at C2 ( r =0.48, P =0.003), C4 ( r =0.41, P =0.01), and C6 ( r =0.53. P <0.001) and indirectly correlated with fat infiltration at C2 ( r =-0.40, P =0.02), C4 ( r =-0.32, P =0.04), and C6 ( r =-0.35, P =0.02). Muscle density correlated directly with reserve of extension at C2 ( r =0.57, P =0.009), C4 ( r =0.48, P =0.037), and C6 ( r =0.47, P =0.033). Reserve of extension indirectly correlated with fat infiltration at C2 ( r =0.65, P =0.006), C4 ( r =0.47, P =0.037), and C6 ( r =0.48, P =0.029). CONCLUSIONS: We have identified specific changes in paracervical muscle that are associated with a patient's ability to extend their cervical spine.

Comparison of Value per Operative Time between Primary and Revision Surgery for Adult Spinal Deformity: A Propensity Score-Matched Analysis.

STUDY DESIGN: Retrospective cohort study. PURPOSE: To compare the relative value units (RVUs) per minute of operative time between primary and revision surgery for adult spinal deformity (ASD). OVERVIEW OF LITERATURE: Surgery for ASD is technically demanding and has high risks of complications and revision rates. This common need for additional surgery can increase the overall cost of care for ASD. RVU is used to calculate reimbursement from Medicare and to determine physician payments nationally. In calculating RVUs, the physician's work, the expenses of the physician's practice, and professional liability insurance. Cost effectiveness of surgeries for ASD have been evaluated, except for RVUs per minute compared between primary and revision surgery. METHODS: Data were obtained from the American College of Surgeons National Surgical Quality Improvement Program database. Patients aged ≥18 years who underwent surgery for spinal deformity between 2011 and 2019 were identified and included. To ensure a homogenous patient cohort, those who underwent anterior-only and concurrent anterior-posterior fusions were excluded. Propensity score matching analysis was performed, and Mann-Whitney U test, Pearson chi-square test, or Fisher's exact test were used to compare matched cohorts as appropriate. RESULTS: A total of 326 patients who underwent revision surgery were matched with 206 primary surgery patients via propensity score matching. Demographic characteristics, comorbidities, preoperative laboratory values, and readmission and reoperation rates were not significantly different between groups. The revision surgery group had significantly higher mean RVUs per minute than that of the primary surgery group (0.331 vs. 0.249, p <0.001), as well as rates of morbidity and blood transfusion. CONCLUSIONS: Compared to primary surgery, revision surgery for ASD is associated with significantly higher RVUs per minute and total RVUs and higher rates of 30-day morbidity and blood transfusions. Readmission and reoperation rates are similar between surgeries.

Impact of Navigation on 30-Day Outcomes for Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective database study. OBJECTIVE: Navigation has been increasingly used to treat degenerative disease, with positive radiographic and clinical outcomes and fewer adverse events and reoperations, despite increased operative time. However, short-term analysis on treating adult spinal deformity (ASD) surgery with navigation is limited, particularly using large nationally represented cohorts. This is the first large-scale database study to compare 30-day readmission, reoperation, morbidity, and value-per-operative time for navigated and conventional ASD surgery. METHODS: Adults were identified in the National Surgical Quality Improvement Program (NSQIP) database. Multivariate regression was used to compare outcomes between navigated and conventional surgery and to control for predictors and baseline differences. RESULTS: 3190 ASD patients were included. Navigated and conventional patients were similar. Navigated cases had greater operative time (405 vs 320 min) and mean RVUs per case (81.3 vs 69.7), and had more supplementary pelvic fixations (26.1 vs 13.4%) and osteotomies (50.3 vs 27.7%) (P <.001).In univariate analysis, navigation had greater reoperation (9.9 vs 5.2%, P = .011), morbidity (57.8 vs 46.8%, P = .007), and transfusion (52.2 vs 41.8%, P = .010) rates. Readmission was similar (11.9 vs 8.4%). In multivariate analysis, navigation predicted reoperation (OR = 1.792, P = .048), but no longer predicted morbidity or transfusion. Most reoperations were infectious and hardware-related. CONCLUSIONS: Despite controlling for patient-related and procedural factors, navigation independently predicted a 79% increased odds of reoperation but did not predict morbidity or transfusion. Readmission was similar between groups. This is explained, in part, by greater operative time and transfusion, which are risk factors for infection. Reoperation most frequently occurred for wound- and hardware-related reasons, suggesting navigation carries an increased risk of infectious-related events beyond increased operative time.

Comparative Analysis of 30-Day Readmission, Reoperation, and Morbidity between Posterior Cervical Decompression and Fusion Performed in Inpatient and Outpatient Settings.

STUDY DESIGN: A retrospective cohort study. PURPOSE: To compare 30-day readmission, reoperation, and morbidity for patients undergoing posterior cervical decompression and fusion (PCDF) in inpatient vs. outpatient settings. OVERVIEW OF LITERATURE: PCDF has recently been increasingly performed in outpatient settings, often utilizing minimally invasive techniques. However, literature evaluating short-term outcomes for PCDF is scarce. Moreover, no currently large-scale database studies have compared short-term outcomes between PCDF performed in the inpatient and outpatient settings. METHODS: Patients who underwent PCDF from 2005 to 2018 were identified using the National Surgical Quality Improvement Program database. Regression analysis was utilized to compare primary outcomes between surgical settings and evaluate for predictors thereof. RESULTS: We identified 8,912 patients. Unadjusted analysis revealed that outpatients had lower readmission (4.7% vs. 8.8%, p =0.020), reoperation (1.7% vs. 3.8%, p =0.038), and morbidity (4.5% vs. 11.2%, p <0.001) rates. After adjusting for baseline differences, readmission, reoperation, and morbidity no longer statistically differed between surgical settings. Outpatients had lower operative time (126 minutes vs. 179 minutes) and levels fused (1.8 vs. 2.2) (p <0.001). Multivariate analysis revealed that age (p =0.008; odds ratio [OR], 1.012), weight loss (p =0.045; OR, 2.444), and increased creatinine (p <0.001; OR, 2.233) independently predicted readmission. The American Society of Anesthesiologists (ASA) classification of ≥3 predicted reoperation (p =0.028; OR, 1.406). Rehabilitation discharge (p <0.001; OR, 1.412), ASA-class of ≥3 (p =0.008; OR, 1.296), decreased hematocrit (p <0.001; OR, 1.700), and operative time (p <0.001; OR, 1.005) predicted morbidity. CONCLUSIONS: The 30-day outcomes were statistically similar between surgical settings, indicating that PCDF can be safely performed as an outpatient procedure. Surrogates for poor health predicted negative outcomes. These results are particularly important as we continue to shift spinal surgery to outpatient centers. This importance has been highlighted by the need to unburden inpatient sites, particularly during public health emergencies, such as the coronavirus disease 2019 pandemic.

Pilot Study on Percutaneous Delivery of Recombinant Human Bone Morphongenetic Protein-2 Augments Fusion in a Nicotine-impaired Rabbit Fusion Model.

STUDY DESIGN: A nicotine-impaired spinal fusion rabbit model. OBJECTIVE: To examine whether controlled delivery of morselized absorbable collagen sponge recombinant human bone morphogenetic protein-2 (rhBMP2) in a delayed manner postsurgery would allow for improved bone healing. SUMMARY OF BACKGROUND DATA: The current delivery method of rhBMP-2 during surgery causes a burst of rhBMP-2, which is not sustained. Given that bone morphogenetic protein 2 (BMP-2) expression peaks later in the fusion process, there may be the benefit of delivery of rhBMP-2 later in the healing process. METHODS: Sixteen male 1-year-old rabbits underwent a posterolateral spinal fusion with iliac crest bone graft at L5-L6 while being given nicotine to prevent spinal fusion as previously published. Eight were controls, whereas 8 had morselized rhBMP-2 (4.2 mg) injected at the fusion site at 4 weeks postoperatively. Histologic, radiologic, and palpation examinations were performed at 12 weeks to determine fusion status and the volume of bone formed. Hematoxylin and eosin stains were used for histology. A Student t test was used to compare the computed tomography scan measured volume of bone created between the control cohort (CC) and rhBMP-2 delayed delivery cohort (BMP-DDC). RESULTS: Of the total, 7/8 rabbits in the BMP-DDC and 5/8 rabbits in the CC formed definitive fusion with a positive palpation examination, bridging bone between transverse processes on computed tomography scan, and an x-ray showing fusion. Histologic analysis revealed newly remodeled bone within the BMP-DDC. There was an increased average volume of bone formed within the BMP-DDC versus the CC (22.6 ± 13.1 vs 11.1 ± 3.6 cm 3 , P = 0.04). CONCLUSION: Our study shows that injectable morselized absorbable collagen sponge/rhBMP-2 can create twice as much bone within a nicotine-impaired rabbit spine fusion model when delivered 4 weeks out from the time of surgery.

Navigated versus conventional pediatric spinal deformity surgery: Navigation independently predicts reoperation and infectious complications.

Context: Literature on treating pediatric spinal deformity with navigation is limited, particularly using large nationally represented cohorts. Further, the comparison of single-institution data to national-level database outcomes is also lacking. Aim: (1) To compare navigated versus conventional posterior pediatric deformity surgery based on 30-day outcomes and perioperative factors using the National Surgical Quality Improvement Program (NSQIP) database and (2) to compare the outcomes of the NSQIP navigated group to those of fluoroscopy-only and navigated cases from a single-institution. Settings and Design: Retrospective cohort study. Subjects and Methods: Pediatric patients who underwent posterior deformity surgery with and without navigation were included. Primary outcomes were 30-day readmission, reoperation, morbidity, and complications. The second part of this study included AIS patients < 18 years old at a single institution between 2015 and 2019. Operative time, length of stay, transfusion rate, and complication rate were compared between single-institution and NSQIP groups. Statistical Analysis Used: Univariate analyses with independent t-test and Chi-square or Fisher's exact test was used. Multivariate analyses through the application of binary logistic regression models. Results: Part I of the study included 16,950 patients, with navigation utilized in 356 patients (2.1%). In multivariate analysis, navigation predicted reoperation, deep wound infection, and sepsis. After controlling for operative year, navigation no longer predicted reoperation. In Part II of the study, 288 single institution AIS patients were matched to 326 navigation patients from the NSQIP database. Operative time and transfusion rate were significantly higher for the NSQIP group. Conclusions: On a national scale, navigation predicted increased odds of reoperation and infectious-related events and yielded greater median relative value units (RVUs) per case but had longer operating room (OR) time and fewer RVUs-per-minute. After controlling for operative year, RVUs-per-minute and reoperation rates were similar between groups. The NSQIP navigated surgery group was associated with significantly higher operative time and transfusion rates compared to the single-institution groups.

Venous Thromboembolism Rates Have Not Decreased in Elective Lumbar Fusion Surgery from 2011 to 2020.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: This study aimed to (1) evaluate for any temporal trends in the rates of VTE, deep venous thrombosis (DVT), pulmonary embolism (PE), and mortality from 2011 to 2020 and (2) identify the predictors of VTE following lumbar fusion surgery. METHODS: Annual incidences of 30-day VTE, DVT, PE, and mortality were calculated for each of the operation year groups from 2011 to 2020. Multivariable Poisson regression was utilized to test the association between operation year and primary outcomes, as well as to identify significant predictors of VTE. RESULTS: A total of 121,205 patients were included. There were no statistically significant differences in VTE, DVT, PE, or mortality rates among the operation year groups. Multivariable regression analysis revealed that compared to 2011, operation year 2019 was associated with significantly lower rates of DVT. Age, BMI, prolonged operation time, prolonged length of stay, non-home discharge, anterior fusion, smoking status, functional dependence, and chronic steroid use were identified as independent predictors of VTE following lumbar fusion. Female sex, Hispanic ethnicity, and outpatient surgery setting were identified as protective factors from VTE in this cohort. CONCLUSIONS: Rates of VTE after lumbar fusion have remained mostly unchanged between 2011 and 2020. Older age, higher BMI, longer operation time, prolonged length of stay, non-home discharge, anterior fusion, smoking, functional dependence, and steroid use were independent predictors of VTE after lumbar fusion, while female sex, Hispanic ethnicity, and outpatient surgery were the protective factors.

Lumbar fusion during the COVID-19 pandemic: greater rates of morbidity and longer procedures.

Background: The coronavirus disease 2019 (COVID-19) pandemic has altered the standard of care for spine surgery in many ways. However, there is a lack of literature evaluating the potential changes in surgical outcomes and perioperative factors for spine procedures performed during the pandemic. In particular, no large database study evaluating the impact of the COVID-19 pandemic on spine surgery outcomes has yet been published. Therefore, the aim of this study was to evaluate the impact of the COVID-19 pandemic on perioperative factors and postoperative outcomes of lumbar fusion procedures. Methods: This retrospective cohort study utilized the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database, which was queried for all adult patients who underwent primary lumbar fusion in 2019 and 2020. Patients were grouped into cohorts based on 2019 (pre-pandemic) or 2020 (intra-pandemic) operation year. Differences in 30-day readmission, reoperation, and morbidity rates were evaluated using multivariate logistic regression. Differences in total relative value units (RVUs), RVUs per minute, and total operation time were evaluated using quantile (median) regression. Odds ratios (OR) for length of stay were estimated via negative binomial regression. Results: A total of 27,446 patients were included in the analysis (12,473 cases in 2020). Unadjusted comparisons of outcomes revealed that lumbar fusions performed in 2020 were associated with higher rates of morbidity, pneumonia, bleeding transfusions, deep venous thrombosis (DVT), and sepsis. 2020 operation year was also associated with longer length of hospital stay, less frequent non-home discharge, higher total RVUs, and higher RVUs per minute. After adjusting for baseline differences in regression analyses, the differences in bleeding transfusions, length of stay, and RVUs per minute were no longer statistically significant. However, operation year 2020 independently predicted morbidity, pneumonia, DVT, and sepsis. In terms of perioperative variables, operation year 2020 predicted greater operative time, non-home discharge, and total RVUs. Conclusions: Lumbar fusion procedures performed amidst the COVID-19 pandemic were associated with poorer outcomes, including higher rates of morbidity, pneumonia, DVT, and sepsis. In addition, surgeries performed in 2020 were associated with longer operative times and less frequent non-home discharge disposition.

Duration of Back Pain Symptoms and Its Relationship to Paralumbar Muscle Volume.

OBJECTIVE: Paralumbar muscle volume has been indicated as an important factor for patients reporting back pain. Our goal was to determine if there is a statistically significant relationship between the duration of patients' back pain symptoms (>12 weeks or ≤12 weeks) and paralumbar muscle volume. METHODS: In this retrospective cohort study, paralumbar muscles on axial T2-weighted lumbar magnetic resonance images were outlined using ImageJ to determine the paralumbar cross-sectional area (PL-CSA) and lumbar indentation value (LIV) at the center of disc spaces from L1 to L5. The Goutallier classification was determined by the primary author. Quantile regression was performed to compare the PL-CSA, PL-CSA normalized by body mass index, and LIV between the 2 cohorts. Cohort A consisted of patients reporting symptoms ≤12 weeks, and cohort B included patients with symptoms >12 weeks. Negative binomial regression was used to compare Goutallier class. RESULTS: A total of 551 patients operated on by a single surgeon with lumbar magnetic resonance imaging within the past 12 months and recorded duration of symptoms were included. Cohort A consisted of 229 patients (41.6%), and cohort B included 322 patients (58.4%). Statistical significance was not found at any lumbar level for PL-CSA, PL-CSA normalized by body mass index, Goutallier class, and LIV. CONCLUSIONS: Our results suggest that duration of symptoms may not be an accurate indicator for lumbar muscle volume. These novel findings are clinically valuable because lumbar muscle volume has been shown to be a marker for recovery. With this information, patients previously believed to be inoperable because of long-standing symptoms can be reevaluated.