The incidence of myocardial infarction after lumbar spine surgery.

PURPOSE: As the population continues to age, the number of lumbar spine surgeries continues to increase. While there are many complications associated with lumbar surgeries, a myocardial infarction (MI) is a particularly devastating one. This complication is of considerable importance with mortality rates of postoperative MI documented between 26.5 and 70%. This study aimed to determine the relationship between lumbar surgeries, preoperative diagnoses (risk factors), and myocardial infarction. METHODS: Data from the Humana database (PearlDiver) were analyzed from 2007 to 2016. Patients undergoing lumbar spine surgeries were identified and stratified based on procedural approach, patient demographics, and preoperative risk factors. Each group was analyzed to determine the incidence and relative risk. Chi-square analysis was used to determine the significance. RESULTS: A total of 105,505 patients who fit inclusion criteria were identified in the PearlDiver database between 2007 and 2016. A total of 644 patients (0.63%) experienced a postoperative myocardial infarction within 30 days of surgery. Patients undergoing fusion and non-fusion procedures showed significantly different rates of postoperative myocardial infarction (0.08% vs. 0.05%, p < 0.01). Male patients, older patients, and patients with a Charlson comorbidity index > 3 showed a considerable increase in incidence (p < 0.01). Furthermore, patients with preoperative risk factors (high cholesterol, obesity, depression, congestive heart failure, hypertension, and hypotension) exhibited risk ratios from 0.01 to 1.85 (p < 0.01). CONCLUSION: Preoperative risk factors, patient demographics, and procedure type had a significant effect on the incidence of postoperative myocardial infarction. These slides can be retrieved under Electronic Supplementary Material.

Top 25 Most Cited Articles on Intraoperative Computer Tomography-Guided Navigation in Spine Surgery.

BACKGROUND: In recent years, the use of intraoperative computer tomography-guided (CT-guided) navigation has gained significant popularity among health care providers who perform minimally invasive spine surgery. This review aims to identify and analyze trends in the literature related to the widespread adoption of CT-guided navigation in spine surgery, emphasizing the shift from conventional fluoroscopy-based techniques to CT-guided navigation. METHODS: Articles pertaining to this study were identified via a database review and were hierarchically organized based on the number of citations. An "advanced document search" was performed on September 28th, 2022, utilizing Boolean search operator terms. The 25 most referenced articles were combined into a primary list after sorting results in descending order based on the total number of citations. RESULTS: The "Top 25" list for intraoperative CT-guided navigation in spine surgery cumulatively received a total of 2742 citations, with an average of 12 new citations annually. The number of citations ranged from 246 for the most cited article to 60 for the 25th most cited article. The most cited article was a paper by Siewerdsen et al., with 246 total citations, averaging 15 new citations per year. CONCLUSIONS: Intraoperative CT-guided navigation is 1 of many technological advances that is used to increase surgical accuracy, and it has become an increasingly popular alternative to conventional fluoroscopy-based techniques. Given the increasing adoption of intraoperative CT-guided navigation in spine surgery, this review provides impactful evidence for its utility in spine surgery.

Chest tube management following two row vertebral body tethering for adolescent idiopathic scoliosis.

BACKGROUND: The current gold standard of scoliosis correction procedures is still posterior spinal fusion, an extensively studied procedure. anterior vertebral body tethering is a newer surgical technique for the correction of scoliotic curves. Consequently, best practices have yet to be determined. METHODS: A single-institution, retrospective, review of all patients diagnosed with adolescent idiopathic scoliosis who underwent two row anterior vertebral body tethering between June 2020 and April 2022 was performed. RESULTS: Over the study period, 95 patients met inclusion: 79 females (83.2%) and 16 males (16.8%), age 14.4 ± 2.5 years, with a body mass index of 20.0 ± 2.9, and an average of 8.4 ± 2.1 levels treated. 28 (29.5%) procedures were for double curves and 67 (70.5%) for single curves. After tethering, a chest tube was positioned in each corrected side. A total of 123 chest tubes were analyzed, including 67 single curves and 28 double curves. The average chest tube duration was 2.5 ± 1.1 days and the average length of stay was 5.0 ± 2.0 days. The average chest tube output eight hours prior to removal was 61.1 ± 45.6 mL. There was no significant difference in average length of stay for patients who underwent correction of a single curve versus a double curve nor was there a difference in average length of stay or chest tube duration for revisions compared to primary procedures. For the entire cohort, the 30-day emergency department visit rate was 7.4% (n = 7) and the readmission rate was 4.2% (n = 4). CONCLUSIONS: This early review of a 2-year two row vertebral body tethering postoperative experience provides a report of a safe and effective approach to chest tube management at a single academic center.

Cervical Disc Arthroplasty: Rationale, Designs, and Results of Randomized Controlled Trials.

BACKGROUND: This review outlines clinical data and characteristics of current Food and Drug Administration (FDA)-approved implants in cervical disc replacement/cervical disc arthroplasty (CDR/CDA) to provide a centralized resource for spine surgeons. METHODS: Randomized controlled trials (RCTs) on CDR/CDA were identified using a search of the PubMed, Web of Science, and Google Scholar databases. The initial search identified 69 studies. Duplicates were removed, and the following inclusion criteria were applied when determining eligibility of RCTs for the current review: (1) discussing CDR/CDA prosthesis and (2) published within between 2010 and 2020. Studies without clinical data or that were not RCTs were excluded. All articles were reviewed independently by 2 authors, with the involvement of an arbitrator to facilitate consensus on any discrepancies. RESULTS: A total of 34 studies were included in the final review. Findings were synthesized into a comprehensive table describing key features and clinical results for each FDA-approved CDR/CDA implant and are overall suggestive of expanding indications and increasing utilization. CONCLUSIONS: RCTs have provided substantial evidence to support CDR/CDA for treating single- and 2-level cervical degenerative disc disease in place of conventional anterior cervical discectomy and fusion. CLINICAL RELEVANCE: This review provides a resource that consolidates relevant clinical data for current FDA-approved implants to help spine surgeons make an informed decision during preoperative planning.

Developing a risk score to inform the use of rhBMP-2 in adult spinal deformity surgery.

BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has not shown superior benefit overall in cost-effectiveness during adult spinal deformity (ASD) surgery. STUDY DESIGN/SETTING: Retrospective PURPOSE: Generate a risk score for pseudarthrosis to inform the utilization of rhBMP-2, balancing costs against quality of life and complications. METHODS: ASD patients with 3-year data were included. Quality of life gained was calculated from ODI to SF-6D and translated to quality-adjusted life years (QALYs). Cost was calculated using the PearlDiver database and CMS definitions for complications and comorbidities. Established weights were generated for predictive variables via logistic regression to yield a predictive risk score for pseudarthrosis that accounted for frailty, diabetes, depression, ASA grade, thoracolumbar kyphosis and three-column osteotomy use. Risk score categories, established via conditional inference tree (CIT)-derived thresholds were tested for cost-utility of rhBMP-2 usage, controlling for age, prior fusion, and baseline deformity and disability. RESULTS: 64% of ASD patients received rhBMP-2 (308/481). There were 17 (3.5%) patients that developed pseudarthrosis. rhBMP-2 use overall did not lower pseudarthrosis rates (OR: 0.5, [0.2-1.3]). Pseudarthrosis rates for each risk category were: No Risk (NoR) 0%; Low-Risk (LowR) 1.6%; Moderate Risk (ModR) 9.3%; High-Risk (HighR) 24.3%. Patients receiving rhBMP-2 had similar QALYs overall to those that did not (0.163 vs. 0.171, p = .65). rhBMP-2 usage had worse cost-utility in the LowR cohort (p < .001). In ModR patients, rhBMP-2 usage had equivocal cost-utility ($53,398 vs. $61,581, p = .232). In the HighR cohort, the cost-utility was reduced via rhBMP-2 usage ($98,328 vs. $211,091, p < .001). CONCLUSION: Our study shows rhBMP-2 demonstrates effective cost-utility for individuals at high risk for developing pseudarthrosis. The generated score can aid spine surgeons in the assessment of risk and enhance justification for the strategic use of rhBMP-2 in the appropriate clinical contexts. LEVEL OF EVIDENCE: III.

Understanding Perioperative Nutrition in Patients Undergoing Spine Surgery.

The consequences of malnutrition in spine surgery have been studied to a lesser degree compared to other orthopedic subspecialties. However, there is growing interest in understanding the effects of preoperative malnutrition on spine surgery outcomes. Literature on the relationship between malnutrition and spine surgery outcomes appeared sporadically in the late 1990s and early 2000s. Over the last decade, however, there has been a push to understand the sequelae of malnutrition on patients undergoing spine surgery. The aims of this review are to highlight: 1. the different parameters by which malnutrition has been defined and measured in spine surgery; 2. the prevalence of malnutrition in spine surgery; 3. the outcomes of spine surgery in malnourished patients; and 4. the effects of nutritional supplementation or interventions on spine surgery outcomes. Malnutrition has often been defined utilizing specific serological laboratory values or nutritional indices. Serologic values of malnutrition include an albumin < 3.5 g/dL, transferrin < 150 mg/ dL, or a total lymphocyte count of < 1,500 cells/mm3 . The available literature reports that the prevalence of malnutrition in patients undergoing lumbar spine surgery ranges from 5% to 50%, with most literature supporting a value toward the higher end of this spectrum. Malnourished patients undergoing spine surgery have higher rates of surgical site infections, medical complications, lengths of stay, ICU admissions, 30-day and 1-year mortalities, reoperations, 30-day readmissions, and costs of care. Given the plethora of spine surgeries performed in the country annually and the prevalence of malnutrition in up to 50% of our patients, we recommend performing preoperative nutritional assessments on all patients to ensure their optimization prior to surgery.

Is There a Difference in Screw Accuracy, Robot Time Per Screw, Robot Abandonment, and Radiation Exposure Between the Mazor X and the Renaissance? A Propensity-Matched Analysis of 1179 Robot-Assisted Screws.

STUDY DESIGN: Prospective single-cohort analysis. OBJECTIVES: To compare the outcomes/complications of 2 robotic systems for spine surgery. METHODS: Adult patients (≥18-years-old) who underwent robot-assisted spine surgery from 2016-2019 were assessed. A propensity score matching (PSM) algorithm was used to match Mazor X to Renaissance cases. Preoperative CT scan for planning and an intraoperative O-arm for screw evaluation were preformed. Outcomes included screw accuracy, robot time/screw, robot abandonment, and radiation. Screw accuracy was measured using Vitrea Core software by 2 orthopedic surgeons. Screw breach was measured according to the Gertzbein/Robbins classification. RESULTS: After PSA, a total of 65 patients (Renaissance: 22 vs. X: 43) were included. Patient/operative factors were similar between robot systems (P > .05). The pedicle screw accuracy was similar between robots (Renaissance: 1.1%% vs. X: 1.3%, P = .786); however, the S2AI screw breach rate was significantly lower for the X (Renaissance: 9.5% vs. X: 1.2%, P = .025). Robot time per screw was not statistically different (Renaissance: 4.6 minutes vs. X: 3.9 minutes, P = .246). The X was more reliable with an abandonment rate of 2.3% vs. Renaissance:22.7%, P = .007. Radiation exposure were not different between robot systems. Non-robot related complications including dural tear, loss of motor/sensory function, and blood transfusion were similar between robot systems. CONCLUSION: This is the first comparative analyses of screw accuracy, robot time/screw, robot abandonment, and radiation exposure between the Mazor X and Renaissance systems. There are substantial improvements in the X robot, particularly in the perioperative planning processes, which likely contribute to the X's superiority in S2AI screw accuracy by nearly 8-fold and robot reliability by nearly 10-fold.

Should Global Realignment Be Tailored to Frailty Status for Patients Undergoing Surgical Intervention for Adult Spinal Deformity?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Assess whether modifying spinal alignment goals to accommodate frailty considerations will decrease mechanical complications and maximize clinical outcomes. SUMMARY OF BACKGROUND DATA: The Global Alignment and Proportion (GAP) score was developed to assist in reducing mechanical complications, but has had less success predicting such events in external validation. Higher frailty and many of its components have been linked to the development of implant failure. Therefore, modifying the GAP score with frailty may strengthen its ability to predict mechanical complications. MATERIALS AND METHODS: We included 412 surgical ASD patients with two-year follow-up. Frailty was quantified using the modified Adult Spinal Deformity Frailty Index (mASD-FI). Outcomes: proximal junctional kyphosis and proximal junctional failure (PJF), major mechanical complications, and "Best Clinical Outcome" (BCO), defined as Oswestry Disability Index<15 and Scoliosis Research Society 22-item Questionnaire Total>4.5. Logistic regression analysis established a six-week score based on GAP score, frailty, and Oswestry Disability Index US Norms. Logistic regression followed by conditional inference tree analysis generated categorical thresholds. Multivariable logistic regression analysis controlling for confounders was used to assess the performance of the frailty-modified GAP score. RESULTS: Baseline frailty categories: 57% not frail, 30% frail, 14% severely frail. Overall, 39 of patients developed proximal junctional kyphosis, 8% PJF, 21% mechanical complications, 22% underwent reoperation, and 15% met BCO. The mASD-FI demonstrated a correlation with developing PJF, mechanical complications, undergoing reoperation, and meeting BCO at two years (all P <0.05). Regression analysis generated the following equation: Frailty-Adjusted Realignment Score (FAR Score)=0.49×mASD-FI+0.38×GAP Score. Thresholds for the FAR score (0-13): proportioned: <3.5, moderately disproportioned: 3.5-7.5, severely disproportioned: >7.5. Multivariable logistic regression assessing FAR score demonstrated associations with mechanical complications, reoperation, and meeting BCO by two years (all P <0.05), whereas the original GAP score was only significant for reoperation. CONCLUSION: This study demonstrated adjusting alignment goals in adult spinal deformity surgery for a patient's baseline frailty status and disability may be useful in minimizing the risk of complications and adverse events, outperforming the original GAP score in terms of prognostic capacity. LEVEL OF EVIDENCE: III.

The influence of modifiable risk factors on short-term postoperative outcomes following cervical spine surgery: A retrospective propensity score matched analysis.

BACKGROUND: Modifiable risk factors (MRFs) represent patient variables associated with increased complication rates that may be prevented. There exists a paucity of studies that comprehensively analyze MRF subgroups and their independent association with postoperative complications in patients undergoing cervical spine surgery. Therefore, the purpose of this study is to compare outcomes between patients receiving cervical spine surgery with reported MRFs. METHODS: Retrospective analysis of the Nationwide Readmissions Database (NRD) from the years 2016 and 2017, a publicly available and purchasable data source, to include adult patients undergoing cervical fusion. MRF cohorts were separated into three categories: substance abuse (alcohol, tobacco/nicotine, opioid abuse); vascular disease (hypertension, dyslipidemia); and dietary factors (malnutrition, obesity). Three-way nearest-neighbor propensity score matching for demographics, hospital, and surgical characteristics was implemented. FINDINGS: We identified 9601 with dietary MRFs (D-MRF), 9654 with substance abuse MRFs (SA-MRF), and 9503 with vascular MRFs (V-MRF). Those with d-MRFs had significantly higher rates of medical complications (9.3%), surgical complications (8.1%), and higher adjusted hospital costs compared to patients with SA-MRFs and V-MRFs. Patients with d-MRFs (16.3%) and V-MRFs (14.0%) were independently non-routinely discharged at a significantly higher rate compared to patients with SA-MRFs (12.6%) (p<0.0001 and p = 0.0037). However, those with substance abuse had the highest readmission rate and were more commonly readmitted for delayed procedure-related infections. INTERPRETATION: A large proportion of patients who receive cervical spine surgery have potential MRFs that uniquely influence their postoperative outcomes. A thorough understanding of patient-specific MRF subgroups allows for improved preoperative risk stratification, tailored patient counseling, and postoperative management planning. FUNDING: None.

Regional gene therapy for bone healing using a 3D printed scaffold in a rat femoral defect model.

At the present time there are no consistently satisfactory treatment options for some challenging bone loss scenarios. We have previously reported on the properties of a novel 3D-printed hydroxyapatite-composite material in a pilot study, which demonstrated osteoconductive properties but was not tested in a rigorous, clinically relevant model. We therefore utilized a rat critical-sized femoral defect model with a scaffold designed to match the dimensions of the bone defect. The scaffolds were implanted in the bone defect after being loaded with cultured rat bone marrow cells (rBMC) transduced with a lentiviral vector carrying the cDNA for BMP-2. This experimental group was compared against 3 negative and positive control groups. The experimental group and positive control group loaded with rhBMP-2 demonstrated statistically equivalent radiographic and histologic healing of the defect site (p > 0.9), and significantly superior to all three negative control groups (p < 0.01). However, the healed defects remained biomechanically inferior to the unoperated, contralateral femurs (p < 0.01). When combined with osteoinductive signals, the scaffolds facilitate new bone formation in the defect. However, the scaffold alone was not sufficient to promote adequate healing, suggesting that it is not substantially osteoinductive as currently structured. The combination of gene therapy with 3D-printed scaffolds is quite promising, but additional work is required to optimize scaffold geometry, cell dosage and delivery.

Evaluating the Standardized Letter of Recommendation Form in Applicants to Orthopaedic Surgery Residency.

INTRODUCTION: A standardized letter of recommendation (SLOR) form for orthopaedic surgery residency programs has recently been adopted for use, but it has not been scientifically evaluated. The purpose of this study is to investigate the usefulness of the SLOR form in the selection process. METHODS: All SLOR forms submitted to our institution over a single application cycle were extracted and analyzed. The United States Medical Licensing Examination Step 1 scores, grades in clinical rotations, Alpha Omega Alpha status, and the number of publications were recorded for each applicant. Correlations were calculated with Spearman rho, and inter-rater reliability was evaluated by calculating intraclass correlation coefficients. RESULTS: One thousand one hundred thirty-seven SLOR forms were analyzed for 513 applicants. There was substantial rank inflation with the SLOR form; the majority (92%) of applicants were rated as either ranked to match or in the top one-third of their rank list. Objective applicant factors such as grades and Step 1 scores demonstrated a very weak to nonexistent correlation with the summative rank (rho 0.07 to 0.13, P ≤ 0.012). Poor inter-rater reliability was observed with the intraclass correlation coefficient ranging from 0.22 to 0.33 (P < 0.001). CONCLUSIONS: The usefulness of the SLOR form is limited by the very high ratings observed for all questions, and in particular, the final summative rank. Measures to reduce rank inflation must be implemented to improve the discriminant ability of the SLOR form, and if this cannot be accomplished, perhaps the form should be abandoned. LEVEL OF EVIDENCE: Level III Retrospective.

Population-based Survivorship of Computer-navigated Versus Conventional Total Knee Arthroplasty.

BACKGROUND: The goal of computer navigation in total knee arthroplasty (TKA) is to improve the accuracy of alignment. However, the relationship between this technology and implant longevity has not been established. The purpose of this study was to analyze survivorship of computer-navigated TKAs compared with traditionally instrumented TKAs. METHODS: The PearlDiver Medicare database was used to identify patients who underwent a primary TKA using conventional instrumentation versus computer navigation between 2005 and 2014. Conventional and computer-navigated cohorts were matched by age, sex, year of procedure, comorbidities, and geographic region. Kaplan-Meier curves were generated to estimate survivorship with aseptic mechanical complications, periprosthetic joint infection, and all-cause revision as end points. RESULTS: During the study period, 75,709 patients who underwent a computer-navigated TKA were identified and matched to a cohort of 75,676 conventional TKA patients from a cohort of 1,607,803 conventional TKA patients. No difference existed in survival between conventional instrumentation (94.7%) and navigated TKAs (95.1%, P = 0.06) at 5 years. A modest decrease was found in revisions secondary to mechanical complications associated with navigation (96.1%) compared with conventional instrumentation (95.7%, P = 0.02) at 5 years. No differences in revision rates because of periprosthetic joint infection were observed (97.9% versus 97.9% event-free survival, P = 0.30). In a subgroup of Medicare patients younger than 65 years of age, use of computer navigation was associated with a decrease in all-cause revision (91.4% versus 89.6% event free survival, P = 0.01) and revision secondary to mechanical complications (89.6% versus 87.8% event-free survival, P = 0.01) at 5 years. DISCUSSION: Among Medicare patients, no notable difference existed in TKA survival associated with the use of computer navigation at the 5-year follow-up. Use of computer navigation was associated with a slight decrease in revisions secondary to mechanical failure. Although improved survivorship was associated with patients younger than 65 years of age who had a navigated TKA, generalizability of these findings is limited given the unique characteristics of this Medicare subpopulation.