The Incidence of Vertebral Artery Injury in Cervical Spine Surgery.

BACKGROUND: Previously reported estimates of vertebral artery injuries (VAIs) during cervical spine surgery relied on self-reported survey studies and retrospective cohorts, which may not be reflective of national averages. The largest study to date reports an incidence of 0.07%; however, significant variation exists between different cervical spine procedures. This study aimed to identify the incidence of VAIs in patients undergoing cervical spine procedures for degenerative pathologies. METHODS: In this retrospective cohort study, a national insurance database was used to access data from the period 2010-2020 of patients who underwent anterior cervical discectomy and fusion, anterior corpectomy, posterior cervical fusion (C3-C7), or C1-C2 posterior fusion for degenerative pathologies. Patients who experienced a VAI were identified, and frequencies for the different procedures were compared. RESULTS: This study included 224,326 patients, and overall incidence of VAIs across all procedures was 0.03%. The highest incidence of VAIs was estimated in C1-C2 posterior fusion (0.12%-1.10%). The number of patients with VAIs after anterior corpectomy, anterior cervical discectomy and fusion, and posterior fusion was 14 (0.06%), 43 (0.02%), and 26 (0.01%), respectively. CONCLUSIONS: This is the largest study to date to our knowledge that provides frequencies of VAIs in patients undergoing cervical spine surgery in the United States. The overall incidence of 0.03% is lower than previously reported estimates, but significant variability exists between procedures, which is an important consideration when counseling patients about risks of surgery.

Delivery of Growth Factors to Enhance Bone Repair.

The management of critical-sized bone defects caused by nonunion, trauma, infection, malignancy, pseudoarthrosis, and osteolysis poses complex reconstruction challenges for orthopedic surgeons. Current treatment modalities, including autograft, allograft, and distraction osteogenesis, are insufficient for the diverse range of pathology encountered in clinical practice, with significant complications associated with each. Therefore, there is significant interest in the development of delivery vehicles for growth factors to aid in bone repair in these settings. This article reviews innovative strategies for the management of critical-sized bone loss, including novel scaffolds designed for controlled release of rhBMP, bioengineered extracellular vesicles for delivery of intracellular signaling molecules, and advances in regional gene therapy for sustained signaling strategies. Improvement in the delivery of growth factors to areas of significant bone loss has the potential to revolutionize current treatment for this complex clinical challenge.

Postoperative Complications Associated with Non-Steroidal Anti-Inflammatory Combinations Used Status-Post Total Hip and Knee Arthroplasty.

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used in multimodal pain control following total joint arthroplasty (TJA). However, few studies have assessed the complications associated with the combinations of NSAIDs in this population despite the known risks associated with this class of medications. The Premier Healthcare Database was queried to identify adults who underwent primary total hip or knee arthroplasty from 2005-2014. The following most common inpatient combinations of NSAIDs were chosen for analysis: aspirin + celecoxib (A + C), toradol + aspirin (T + A), toradol + ibuprofen (T + I), celecoxib + ibuprofen (C + I), ibuprofen + aspirin (I + A), and toradol + celecoxib (T + C). Primary outcomes included acute kidney injury (AKI), gastrointestinal bleed, and stroke. Secondary outcomes included periprosthetic joint infection (PJI), deep vein thrombosis, and pulmonary embolism. Univariate and multivariate regression analyses were used to compare differences and address confounds. Overall, 195,833 patients were identified. After controlling for confounds, increased odds of AKI was associated with A + C (adjusted odds ratio [aOR]: 1.20, 95% confidence interval [CI]: 1.09-1.34, p < 0.001) and decreased odds was associated with T + A (aOR 0.76, 95% CI: 0.69-0.83, p < 0.001). Increased odds of stroke was associated with A + C (aOR: 1.80, 95% CI: 1.15-2.84, p = 0.011); T + I (aOR 3.48, 95% CI: 1.25-9.73, p = 0.017); and I + A (aOR 4.29, 95% CI: 1.06-17.9, p = 0.046). Increased odds of PJI was associated with C + I (aOR: 10.3, 95% CI: 1.35-78.3, p = 0.024). In the TJA patient population, NSAID pairings should be regarded as distinct entities. Our results suggest that combinations including A + C, T + I, I + A, and C + I should be used cautiously. With this knowledge, providers should consider tailoring NSAID prescriptions appropriately.

Development and characterization of an automated active mixing platform for hydrogel bioink preparation.

Bioink preparation is an important yet challenging step for bioprinting with hydrogels, as it involves fast and homogeneous mixing of various viscous components. In this study, we have developed an automated active mixing platform (AAMP), which allows for high-quality preparation of hydrogel bioinks. The design of AAMP, adapted from syringe pumps, provides many advantages, including low cost, automated control, high precision, customizability, and great cytocompatibility, as well as the potential to intelligently detect the homogeneity. To demonstrate the capability of AAMP, mixing of different hydrogel components, including alginate and xanthan gum with and without Ca2+, alginate and Laponite, PEGDMA and xanthan gum, was performed to investigate an alginate hydrogel preparation process. Colorimetric analyses were carried out to evaluate the mixing outcome with AAMP. Result showed that AAMP can prepare homogeneous hydrogel mixing in a fast and automated fashion. A multiphysics COMSOL simulation is carried out to further validate the results. Moreover, cell viability and proliferation study were performed in a cell encapsulation mixing experiment to validate the cytocompatibility of the AAMP. The AAMP has demonstrated great capability in hydrogel bioink preparation and could therefore holds great promise and wide applications in bioprinting and tissue engineering.

Are Cervical Disc Arthroplasty Medicare Reimbursement Trends Sustainable?

BACKGROUND: Cervical disc arthroplasty (CDA) was originally approved by the US Food and Drug Administration (FDA) in 2007 as a motion-sparing procedure to treat cervical degenerative disc disease. Since then, promising results from randomized control trials have led to increasing popularity. However, data discussing monetary trends are limited. The aim of this study was to determine how utilization, hospital charges, and Medicare physician reimbursement for CDA have changed over time. METHODS: In this retrospective cohort study, International Classification of Diseases procedure codes were used to identify all patients who underwent CDA from 2007 to 2017 in the National Inpatient Sample database. The Physician Fee Schedule Look-up Tool from the Centers for Medicare and Medicaid Services was queried for primary CDA using current procedural terminology codes to determine Medicare physician reimbursement from 2009 to 2021. Nominal monetary values were adjusted for inflation using the Consumer Price Index and inflation-adjusted data reported in 2021 US dollars. RESULTS: A total of 33,079 weighted patients who underwent CDA were included for analysis. CDA utilization increased by 183% from 2007 to 2017, with Medicare beneficiary utilization increasing 149%. Inflation-adjusted total hospital charges for CDA increased by 22.4%. However, inflation-adjusted Medicare physician reimbursement fell by 1.20% per year, demonstrating a total decrease of 12.9%, starting at $1928 in 2009 and declining to $1679 in 2021. CONCLUSIONS: While utilization and total hospital charges for CDA continue to rise, Medicare physician reimbursement has not shown the same trend. In fact, inflation-adjusted reimbursement has seen a steady decline since FDA approval in 2007. If this trend persists, it may become unsustainable for physicians to continue offering CDA to Medicare patients. As disproportionate increases in hospital charges incentivize a transition to outpatient CDA, stricter patient selection criteria associated with outpatient procedures may create health care disparities for Medicare patients and those with higher comorbidity burden. CLINICAL RELEVANCE: This study shows the decreasing reimbursement trends for CDA, which may disproportionately affect Medicare patients and those with increased comorbidities.

Preoperative Epidural Steroid Injection Does Not Increase Infection Risk Following Posterior Cervical Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The purpose of this study was to characterize the infection risk of preoperative epidural steroid injection (ESI) in patients undergoing posterior cervical surgery. SUMMARY OF BACKGROUND DATA: ESI is a helpful tool for alleviating pain and is often used as a diagnostic tool before cervical surgery. However, a recent small-scale study found that ESI before cervical fusion was associated with an increased risk of postoperative infection. MATERIALS AND METHODS: Patients from 2010 to 2020 with cervical myelopathy, spondylosis, and radiculopathy who underwent posterior cervical procedure including laminectomy, laminoforaminotomy, fusion, or laminoplasty were queried from the PearlDiver database. Patients who underwent revision or fusion above C2 or who had a diagnosis of neoplasm, trauma, or preexisting infection were excluded. Patients were divided on whether they received an ESI within 30 days before the procedure and subsequently matched by age, sex, and preoperative comorbidities. The χ 2 analysis was used to calculate the risk of postoperative infection within 90 days. Logistic regression controlling for age, sex, Elixhauser Comorbidity Index, and operated levels was conducted within the unmatched population to assess infection risk for injected patients across procedure subgroups. RESULTS: Overall, 299,417 patients were identified with 3897 having received a preoperative ESI and 295,520 who did not. Matching resulted in 975 in the injected group and 1929 in the control group. There was no significant difference in postoperative infection rate in those who received an ESI within 30 days preoperatively and those who did not (3.28% vs. 3.78%, odds ratio=0.86, 95% CI: 0.57-1.32, P =0.494). Logistic regression accounting for age, sex, Elixhauser Comorbidity Index, and levels operated demonstrated that injection did not significantly increase infection risk in any of the procedure subgroups. CONCLUSIONS: The present study found no association between preoperative ESI within 30 days before surgery and postoperative infection in patients undergoing posterior cervical surgery.

The Role of Sex Hormones in Degenerative Disc Disease.

STUDY DESIGN: Narrative review. OBJECTIVES: The purpose of this review is to outline the role of sex hormones, particularly estrogen, in the pathogenesis of degenerative disc disease (DDD). METHODS: A narrative review of studies discussing sex hormones and intervertebral disc (IVD) degeneration was conducted through a search of bibliographic databases to identify various mechanisms involved in effectuating DDD. RESULTS: Estrogen-deficient states negatively impact various aspects of IVD function. These internal hormone environments reflect routine changes that commonly arise with physiologic aging and can compromise IVD structural integrity through a host of processes. Additionally, allosteric molecules such as micro-RNAs (mi-RNAs) and G protein-coupled estrogen receptors (GPER) antagonists can bind to estrogen receptors and inhibit protective downstream effects with estrogen receptor signaling. Furthermore, cursory studies have observed chondrogenic effects with testosterone supplementation, although the specific mechanism remains unclear. CONCLUSIONS: Regulation of sex hormones, namely estrogen and testosterone, significantly impacts the structural integrity and function of IVDs. Uncovering underlying interactions driving these regulatory processes can facilitate development of novel, clinical therapies to treat DDD.

A Decreasing National Trend in Lumbar Disc Arthroplasty.

STUDY DESIGN: Retrospective National Database Study. OBJECTIVES: The aim of this study was to investigate the national trend of lumbar disc arthroplasty (LDA) utilization from 2005 to 2017. METHODS: Patients undergoing primary LDA between 2005 and 2017 were identified in the National Inpatient Sample (NIS) database. Year of the procedure, demographic, socioeconomic, hospital, and cost parameters were analyzed. The data was weighted using provided weights from the NIS database to generate national estimates of LDA procedure incidence. Lastly, we assessed the incidence of cervical disc arthroplasty (CDA) between 2005 and 2017 to serve as a historical comparison. RESULTS: An estimated 20 460 patients underwent primary LDA in the United States between 2005 and 2017. There was an initial decrease in LDA procedures between 2005 and 2006 and then a plateau between 2006 and 2009. From 2010 to 2013, there was a significant year-over-year decrease in annual LDA procedures performed, followed by a second plateau from 2014 to 2017. Overall, LDA procedures decreased 82% from 2005 to 2017. Over the same time, the annual incidence of CDA utilization increased 795% from approximately 474 procedures in 2005 to 4245 procedures in 2017 (P < .01). CONCLUSIONS: Lumbar disc arthroplasty utilization decreased 82% from 2005 to 2017, with a significant decrease in the rate of utilization noted after 2010. The utilization of LDA to treat selected degenerative lumbar conditions has not paralleled the increasing popularity of CDA, and, in fact, has demonstrated a nearly opposite utilization trend.

Incidence of injuries among lacrosse athletes: a systematic review and meta-analysis.

OBJECTIVES: The purpose of this systematic review was to determine the incidence of injuries among lacrosse athletes and the differences in rates of injury by location and gender. METHODS: The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were implemented to conduct this systematic review.[1] The following variables were extracted from each of the included articles: location of injury, gender of patient, and incidence of injury among study population. The methodological quality of the included studies was assessed using mixed-methods appraisal tool (MMAT) version 2018.[2] Estimated rates were reported as pooled proportion with 95% CI. Rates of injury were calculated as a rate per 1000 athletic exposures (AEs), defined as an athlete participating in 1 practice or competition in which he or she was exposed to the possibility of athletic injury. RESULTS: This study found that the highest injury rate among lacrosse athletes was to the lower leg/ankle/foot with a rate of 0.66 injuries per 1000 AEs (95% CI, 0.51, 0.82). This injury pattern was also found to be the highest among both male and female lacrosse athletes. No statistical significance was detected when comparing rates of injury across gender, regardless of location. The injury pattern with the lowest rates of injury for female athletes being to the shoulder/clavicle and the neck for male athletes. CONCLUSION: The highest rate of injury among lacrosse athletes was to the lower leg/ankle/foot. As participation in lacrosse continues to rise, there is a greater need for understanding the rate of injury and injury characteristics for physicians and trainers to provide effective care to lacrosse athletes.

The biomechanics of osteoarthritis in the hand: Implications and prospects for hand therapy.

BACKGROUND: The unique anatomy of the human hand makes it possible to carefully manipulate tools, powerfully grasp objects, and even throw items with precision. These apparent contradictory functions of the hand, high mobility for manual dexterity vs high stability during forceful grasping, imply that daily activities impose a high strain on a relatively instable joint. This makes the hand susceptible to joint disorders such as osteoarthritis. Both systemic (eg, genetics, hormones) and mechanical factors (eg, joint loading) are important in the development of osteoarthritis, but the precise pathomechanism remains largely unknown. This paper focuses on the biomechanical factors in the disease process and how hand therapists can use this knowledge to improve treatment and research. CONCLUSION: Multiple factors are involved in the onset and development of osteoarthritis in the hand. Comprehension of the biomechanics helps clinicians establish best practices for orthotics intervention, exercise, and joint protection programs even in de absence of clear evidence-based guidelines. The effect and reach of hand therapy for OA patients can be expanded substantially when intervention parameters are optimized and barriers to early referrals, access reimbursement, and adherence are addressed. Close and early collaboration between hand therapists and primary care, women's health, rheumatology, and hand surgery providers upon diagnosis, and with hand surgeons pre and postoperatively, combined with advances in the supporting science and strategies to enhance adherence, appear to be a promising way forward.

Single position lumbar fusion: a systematic review and meta-analysis.

BACKGROUND CONTEXT: Recently, a single position lumbar fusion has been described in which both the anterior or lateral interbody fusion as well as posterior percutaneous pedicle screw fixation are performed in a single position. PURPOSE: The purpose of this study was to present and analyze the current evidence for single position lumbar fusion. STUDY DESIGN/SETTING: This is a systematic review and meta-analysis. PATIENT SAMPLE: Prospective or retrospective studies published in English that assessed outcomes of single position lumbar fusion surgery for patients with lumbar degenerative disease, spondylolisthesis, or radiculopathy were included. OUTCOME MEASURES: Outcome measures included operative time, estimated blood loss, hospital length of stay, X-Ray exposure time, and postoperative outcomes including leg numbness or pain, leg weakness, lumbar lordosis, and segmental lordosis. METHODS: This systematic review was performed in accordance with PRISMA guidelines. Two separate meta-analyses were performed. The first compared single position (SP) surgery, both lateral and prone, to dual position or flipped (F) surgery. The second meta-analysis compared lateral single position (LSP) surgery to prone single position (PSP) surgery. Variables were included if (1) they were a mean with a reported standard deviation or (2) if they were a categorical variable. For calculating standard error of the mean, we used sample size, mean, and standard deviation. A random effects model was used. The heterogeneity among studies was assessed with a significance level of <0.05. RESULTS: Twenty-one articles were included for analysis. Three studies were prospective nonrandomized studies, while 18 were retrospective. Seven articles studied lateral single position only, 10 articles compared lateral single position to traditional repositioning surgery, three articles studied prone single position surgery, and one article compared prone single position surgery to traditional repositioning surgery. A detailed review is provided for all 21 articles. Seventeen studies were included for meta-analysis comparing the SP versus F groups, for a total of 942 patients in the SP group and 254 in the F group. Mean operative time was significantly less for the SP group compared with the F group (SP: 127.5±7.9, F: 188.7±15.5, p<.001). Average hospital length of stay was 2.87±0.3 days in the SP group and 6.63±0.6 days in the F group (p<.001). Complication rates did not significantly differ between groups. Pedicle screws placed in the lateral position had a higher rate of complication as compared with those placed in a prone position (L: 10.2±2%, P: 1.6±1%, p=.015). Seventeen studies were included in the LSP versus PSP analysis, including 13 in the LSP group and four in the PSP group, with a total of 785 patients in the LSP group and 85 patients in the PSP group. Operative time and X-Ray exposure was significantly less in the LSP compared with the PSP group (117.1±5.5 minutes vs. 166.9±21.9 minutes, p<.001; 43.7±15.5 minutes vs. 171.0±25.8 minutes, p<.001). Postoperative segmental lordosis was greater in the prone single position group (p<.001). CONCLUSIONS: Single position surgery decreases operative times and hospital length of stay, while maintaining similar complication rates and radiographic outcomes. PSP surgery was found to be longer in duration and have increased radiation exposure time compared with LSP, while increasing postoperative segmental lordosis.

Somatic Lineage Reprogramming.

Embryonic development and cell specification have been viewed as an epigenetically rigid process. Through accumulation of irreversible epigenetic marks, the differentiation process has been considered unidirectional, and once completed cell specification would be permanent and stable. However, somatic cell nuclear transfer that involved the implantation of a somatic nucleus into a previously enucleated oocyte accomplished in amphibians in the 1950s and in mammals in the late 1990s-resulting in the birth of "Dolly the sheep"-clearly showed that "terminal" differentiation is reversible. In parallel, work on lineage-determining factors like MyoD revealed surprising potential to modulate lineage identity in somatic cells. This work culminated in the discovery that a set of four defined factors can reprogram fibroblasts into induced pluripotent stem (iPS) cells, which were shown to be molecularly and functionally equivalent to blastocyst-derived embryonic stem (ES) cells, thus essentially showing that defined factors can induce authentic reprogramming without the need of oocytes. This concept was further extended when it was shown that fibroblasts can be directly converted into neurons, showing induced lineage conversion is possible even between cells representing two different germ layers. These findings suggest that "everything is possible" (i.e., once key lineage reprogramming factors are identified, cells should be able to convert into any desired lineage).

Open Stabilization Procedures of the Shoulder in the Athlete: Indications, Techniques, and Outcomes.

Shoulder instability is a relatively common injury especially in the young athletic population and its surgical management continues to remain a controversial topic in sports medicine orthopedics. Anterior instability is the most common type encountered and is estimated to have an incidence rate of 0.08 per 1000 person-years in the general population; however, this figure is likely higher in the young athletic population. While in recent practice, arthroscopic surgery has become the new gold standard for management, reported failure rates as high as 26% and high recurrence rates in specific subpopulations such as young men in high collision sports have led to the consideration of alternative open procedures such as open Bankart repair, Latarjet, capsular shift, and glenoid bone grafting. These procedures may be preferred in specific patient subgroups such as young athletes involved in contact sports and those with Hill-Sachs defects and multidirectional instability, with postoperative recurrence rates of instability as low as 10%. The purpose of this review is to provide an overview of different open surgical techniques in the management of shoulder instability and summarize patient outcomes including recurrence rates for shoulder instability, return to sport, range of motion (ROM), muscle strength, and complications either individually by procedure or in comparison with other techniques, with special focus on their impact in the athletic population.

Utilization of Tranexamic Acid in Surgical Orthopaedic Practice: Indications and Current Considerations.

Tranexamic acid (TXA) is a lysine analog that exhibits an anti-fibrinolytic effect by directly preventing the activation of plasminogen as well as inhibiting activated plasmin from degrading fibrin clots, thereby promoting hemostasis and reducing the duration and quantity of blood loss. The aims of this study were to summarize the indications, routes of administration, safety, and clinical outcomes of TXA use throughout the different subspecialities in orthopedic surgery. Given that orthopedic procedures such as TKA, THA, fracture fixation, and various spine surgeries involve significant intraoperative blood loss, TXA is indicated in providing effective perioperative hemostasis. Additionally, use of TXA in orthopedic trauma has been indicated as a measure to reduce blood loss especially in a group with potential for hemodynamic compromise. TXA has been implicated in reducing the risk of blood transfusions in orthopedic trauma, joint surgery, and spine surgery, although this effect is not seen as prominently in sports medicine procedures. There remains disagreement in literature as to whether TXA via any route of administration can improve other clinically significant outcomes such as hospital length of stay and total operative time. Procedures that rely extensively on clarity on visualization of the surgical field such as knee and shoulder arthroscopies can greatly benefit from the use of TXA, thereby leading to less intraoperative bleeding, with better visual clarity of the surgical field. While most studies agree thrombosis due to TXA is unlikely, new research in cells and animal models are evaluating whether TXA can negatively impact other aspects of musculoskeletal physiology, however with conflicting results thus far. As of now, TXA remains a safe and effective means of promoting hemostasis and reducing intraoperative blood loss in orthopedic surgery.

Intraoperative Neuromonitoring During Lateral Lumbar Interbody Fusion.

OBJECTIVE: To review the evidence for the use of electromyography (EMG), motor-evoked potentials (MEPs), and somatosensory-evoked potentials (SSEPs) intraoperative neuromonitoring (IONM) strategies during lateral lumbar interbody fusion (LLIF), as well as discuss the limitations associated with each technique. METHODS: A comprehensive review of the literature and compilation of findings relating to clinical studies investigating the efficacy of EMG, MEP, SSEP, or combined IONM strategies during LLIF. RESULTS: The evidence for the use of EMG is mixed with some studies demonstrating the efficacy of EMG in preventing postoperative neurologic injuries and other studies demonstrating a high rate of postoperative neurologic deficits with EMG monitoring. Multimodal IONM strategies utilizing MEPs or saphenous SSEPs to monitor the lumbar plexus may be promising strategies based on results from a limited number of studies. CONCLUSION: The use of traditional EMG during LLIF remains without consensus. There is a growing body of evidence utilizing multimodal IONM with MEPs or saphenous SSEPs demonstrating a possible decrease in postoperative neurologic injuries after LLIF. Future prospective studies, with clear definitions of neurologic injury, that evaluate different multimodal IONM strategies are needed to better assess the efficacy of IONM during LLIF.