Surgeon Experience Is the Most Important Predictor of Case Failure Rate for Anterior Odontoid Screw Fixation: A Large Database Study.

STUDY DESIGN: Retrospective database analysis. OBJECTIVE: Determine risk factors and failure rate of anterior odontoid screw fixation surgery. SUMMARY OF BACKGROUND DATA: Anterior odontoid screw fixation (AOSF) stabilizes type II dens fractures while preserving cervical motion. Despite having potential advantages, AOSF's failure rate and factors contributing to failure remain unknown. MATERIALS AND METHODS: We identified AOSF patients in the national claims database Pearldiver using CPT code 22318. Failure was defined as the requirement of supplementary posterior fusion surgery in the C1-C2 or occiput-C2 region after the AOSF. We considered potential predictors of failure including age, sex, Charlson Comorbidity Index (CCI), surgeon experience, history of osteoporosis, obesity, and tobacco use. Univariate comparison analysis and logistic regression were conducted to identify factors associated with the need for additional posterior surgery. RESULTS: For 2008 identified cases of AOSF, 249 cases (12.4%) required additional posterior fusion. Seventy-one of the 249 cases (28.5%) underwent revision surgery on the same day as the AOSF. Over 86% of revisions (215 cases) occurred within 200 days of the initial procedure. Posterior fusion rates are inversely correlated with surgeon experience, with the most experienced surgeons having a rate of 10.0%, followed by 11.5% for moderately experienced surgeons, and 15.0% for the least experienced surgeons. When comparing moderate and inexperienced surgeons to experienced surgeons, the odds ratios for posterior fusion were 1.18 ( P >0.05) and 1.61 ( P <0.006), respectively. Logistic regression revealed that both lesser experience (odds ratio=1.50) and osteoporosis (odds ratio=1.44) were the only factors significantly associated with failure ( P <0.05). CONCLUSIONS: Our findings indicate a correlation between AOSF success and surgeon experience. While currently published results suggest higher success rates, most of this data originates from experienced surgeons and specialized centers, therefore, they may not accurately reflect the failure rate encountered in a more general practice setting. LEVEL OF EVIDENCE: Level III.

Age-Based Incidence of Dens Fracture Has Unimodal Distribution Rather Than Commonly Claimed Bimodal Distribution.

Background: Type-II dens fractures have long been described in the literature as occurring in a bimodal distribution, peaking in young adulthood as well as in older adulthood; however, the origin of this claim is unclear. The primary goal of this study was to examine the incidence of type-II dens fractures and assess for bimodality. Methods: This is a retrospective cross-sectional review of the National Trauma Data Bank (NTDB) records on traumatic type-II dens fractures between October 2015 and December 2016. Rates were obtained from the NTDB, and the incidence per 100,000 was ascertained by utilizing U.S. Census data from 2016. Subgroupings by gender and Black or White race were also examined. Results: Dens fractures occur unimodally, peaking around 89 years of age overall, skewed left by high rates in older White adults. The Black subgroup demonstrated trimodality, with the fracture incidence peaking at 25, 62, and 82 years of age. Rates among Black and White patients were similar until age 65, after which dens fractures occurred disproportionately in White patients. Fractures prior to age 75 occurred predominantly in men. Conclusions: The evidence derived in this study challenges the common belief that type-II dens fractures occur bimodally across the entire population. However, there remains utility in considering younger and older patients as distinct groups for the purposes of management.

Characterizing utilization patterns and reoperation risk factors of interspinous process devices: analysis of a national claims database.

INTRODUCTION: Interspinous process devices (IPDs) were developed as minimally invasive alternatives to open decompression surgery for spinal stenosis. However, given high treatment failure and reoperation rates, there has been minimal adoption by spine surgeons. This study leveraged a national claims database to characterize national IPD usage patterns and postoperative outcomes after IPD implantation. METHOD: Using the PearlDiver database, we identified all patients who underwent 1- or 2-level IPD implantation between 2010 and 2018. Univariate and multivariable logistic regression was performed to identify predictors of the number of IPD levels implanted and reoperation up to 3 years after the index surgery. Right-censored Kaplan-Meier curves were plotted for duration of reoperation-free survival and compared with log-rank tests. RESULTS: Patients (n = 4865) received 1-level (n = 3246) or 2-level (n = 1619) IPDs. Patients who were older (adjusted odds ratio [aOR] 1.02, 95% confidence interval [CI] 1.01-1.03, P < .001), male (aOR 1.31, 95% CI 116-1.50, P < .001), and obese (aOR 1.19, 95% CI 1.05-1.36, P < .01) were significantly more likely to receive a 2-level IPD than to receive a 1-level IPD. The 3-year reoperation rate was 9.3% of patients when mortality was accounted for during the follow-up period. Older age decreased (aOR 0.97, 95% CI 0.97-0.99, P = .0039) likelihood of reoperation, whereas 1-level IPD (aOR 1.37, 95% CI 1.01-1.89, P = .048), Charlson Comorbidity Index (aOR 1.07, 95% CI 1.01-1.14, P = .018), and performing concomitant open decompression increased the likelihood of reoperation (aOR 1.68, 95% CI 1.35-2.09, P = .0014). CONCLUSION: Compared with 1-level IPDs, 2-level IPDs were implanted more frequently in older, male, and obese patients. The 3-year reoperation rate was 9.3%. Concomitant open decompression with IPD placement was identified as a significant risk factor for subsequent reoperation and warrants future investigation.

Utilization of Vertebroplasty/Kyphoplasty in the Management of Compression Fractures: National Trends and Predictors of Vertebroplasty/Kyphoplasty.

OBJECTIVE: The purpose of this study is to examine the utilization of kyphoplasty/vertebroplasty procedures in the management of compression fractures. With the growing elderly population and the associated increase in rates of osteoporosis, vertebral compression fractures have become a daily encounter for spine surgeons. However, there remains a lack of consensus on the optimal management of this patient population. METHODS: A retrospective analysis of 91 million longitudinally followed patients from 2016 to 2019 was performed using the PearlDiver Patient Claims Database. Patients with compression fractures were identified using International Classification of Disease, 10th Revision codes, and a subset of patients who received kyphoplasty/vertebroplasty were identified using Common Procedural Terminology codes. Baseline demographic and clinical data between groups were acquired. Multivariable regression analysis was performed to determine predictors of receiving kyphoplasty/vertebroplasty. RESULTS: A total of 348,457 patients with compression fractures were identified with 9.2% of patients receiving kyphoplasty/vertebroplasty as their initial treatment. Of these patients, 43.5% underwent additional kyphoplasty/vertebroplasty 30 days after initial intervention. Patients receiving kyphoplasty/vertebroplasty were significantly older (72.2 vs. 67.9, p < 0.05), female, obese, had active smoking status and had higher Elixhauser Comorbidity Index scores. Multivariable analysis demonstrated that female sex, smoking status, and obesity were the 3 strongest predictors of receiving kyphoplasty/vertebroplasty (odds ratio, 1.27, 1.24, and 1.14, respectively). The annual rate of kyphoplasty/vertebroplasty did not change significantly (range, 8%-11%). CONCLUSION: The majority of vertebral compression fractures are managed nonoperatively. However, certain patient factors such as smoking status, obesity, female sex, older age, osteoporosis, and greater comorbidities are predictors of undergoing kyphoplasty/vertebroplasty.

Increase in Osteoporotic U-Type Sacral Fractures: Role of the Transiliac-Transsacral Screw Versus Lumbopelvic Fixation.

SUMMARY: As the population is increasing in age, so increases the number of osteoporotic fractures. U-shaped sacral fractures can be difficult to diagnose and may be a source of disability in patients when left untreated. Many patients with osteoporotic fractures are of advanced age and may experience rapid medical decline when these fractures cause immobility. We present surgical options for U-shaped sacral fracture management.

The Use of Tranexamic Acid to Reduce Surgical Blood Loss: A Review Basic Science, Subspecialty Studies, and The Evolution of Use in Spine Deformity Surgery.

Significant blood loss is often seen in orthopedic surgeries, especially complex spinal procedures that constitute long surgical times, large incisions, and rich blood supplies. Tranexamic acid (TXA), a synthetic analog of the amino acid lysine, has proven to be a cost-effective method in decreasing transfusion rates and avoiding complications associated with low blood volume. Recent data on TXA's use in spine surgery suggest that TXA remains both efficacious and safe, although the ideal dosing and timing of administration is still a point of disagreement. The purpose of this study is to review the literature for the use of TXA in spine surgery to better understand its safety profile and ideal dosage. This narrative review on TXA was conducted on prospective orthopedic studies that used TXA in spine deformity surgery. TXA in adult and pediatric spine surgery has decreased intraoperative and postoperative blood loss, decreasing the need for blood transfusions. The most common dose in the literature is a 10 mg/kg loading dose, followed by 1 mg/kg per hour. Although the proper dosing of TXA for spine surgery remains debatable, studies have proven that TXA is effective at reducing blood loss without increasing the risk of thrombotic events.

Inside out: a novel labral repair and advancement technique.

Labral tears are a significant cause of hip pain and are currently the most common indication for hip arthroscopy. Compared with labral debridement, labral repair has significantly better outcomes in terms of both daily activities and athletic pursuits in the setting of femoral acetabular impingement. The techniques described in the literature all use anchor placement on the capsular aspect of the acetabular rim, which can be difficult especially anteriorly, where the rim is very thin, and has the potential for significant complications. Anchor breakage, anchor slippage into the surrounding (capsular side) soft tissue, and penetration of the cartilage surface are among the most common complications. We describe an intra-articular anchor placement technique for labral repair from inside out. This technique, because of the location of the anchor and direction of suture pull, can assist in labral advancement in cases in which the native labrum fails to create a seal because of its location away from the femoral head.

AltitudeOmics: the integrative physiology of human acclimatization to hypobaric hypoxia and its retention upon reascent.

An understanding of human responses to hypoxia is important for the health of millions of people worldwide who visit, live, or work in the hypoxic environment encountered at high altitudes. In spite of dozens of studies over the last 100 years, the basic mechanisms controlling acclimatization to hypoxia remain largely unknown. The AltitudeOmics project aimed to bridge this gap. Our goals were 1) to describe a phenotype for successful acclimatization and assess its retention and 2) use these findings as a foundation for companion mechanistic studies. Our approach was to characterize acclimatization by measuring changes in arterial oxygenation and hemoglobin concentration [Hb], acute mountain sickness (AMS), cognitive function, and exercise performance in 21 subjects as they acclimatized to 5260 m over 16 days. We then focused on the retention of acclimatization by having subjects reascend to 5260 m after either 7 (n = 14) or 21 (n = 7) days at 1525 m. At 16 days at 5260 m we observed: 1) increases in arterial oxygenation and [Hb] (compared to acute hypoxia: PaO2 rose 9±4 mmHg to 45±4 while PaCO2 dropped a further 6±3 mmHg to 21±3, and [Hb] rose 1.8±0.7 g/dL to 16±2 g/dL; 2) no AMS; 3) improved cognitive function; and 4) improved exercise performance by 8±8% (all changes p<0.01). Upon reascent, we observed retention of arterial oxygenation but not [Hb], protection from AMS, retention of exercise performance, less retention of cognitive function; and noted that some of these effects lasted for 21 days. Taken together, these findings reveal new information about retention of acclimatization, and can be used as a physiological foundation to explore the molecular mechanisms of acclimatization and its retention.

Fission yeast Rad26ATRIP delays spindle-pole-body separation following interphase microtubule damage.

The conserved fission yeast protein Rad26(ATRIP) preserves genomic stability by occupying central positions within DNA-structure checkpoint pathways. It is also required for proper cellular morphology, chromosome stability and following treatment with microtubule poisons. Here, we report that mutation of a putative nuclear export sequence in Rad26(ATRIP) disrupted its cytoplasmic localization in untreated cells and conferred abnormal cellular morphology, minichromosome instability and sensitivity to microtubule poisons without affecting DNA-structure checkpoint signaling. This mutation also disrupted a delay to spindle-pole-body separation that occurred following microtubule damage in G(2). Together, these results demonstrate that Rad26(ATRIP) participates in two genetically defined checkpoint pathways--one that responds to genomic damage and the other to microtubule damage. This response to microtubule damage delays spindle-pole-body separation and, in doing so, might preserve both cellular morphology and chromosome stability.