Role of Topical Tranexamic Acid on Blood Loss and Transfusion Requirements in Spinal Fusion for Neuromuscular and Syndromic Scoliosis.

STUDY DESIGN: Retrospective case control study. OBJECTIVES: To determine the role of TXA when used as topical soaked sponges (tTXA) on peri-operative blood loss and changes in hemoglobin following posterior spinal fusion (PSF) for neuromuscular and syndromic scoliosis (NMS). METHODS: A single center review of NMS patients who underwent PSF was conducted. The initial set of patients where no tTXA (control) was used were compared to consecutive NMS patients in whom tTXA was used. In the tTXA group, sponges soaked in 1g TXA in 500 mL normal saline were packed in the wound instead of dry sponges. Estimated blood loss (EBL) was calculated intraoperatively using a standard way. Pre-operative, intra-operative and immediate post-operative variables were collected and compared between the 2 groups. RESULTS: 33 patients were included (mean age- 13.5 yrs., BMI- 21, 17 patients in tTXA and 16 patients in control group). Pre-op demographic and radiographic variables were similar between the 2 groups. EBL, EBL per level, EBVL, operative time and number of levels fused were similar in both groups. tTXA group received less intra-operative pRBC transfusion as compared to the control group (150 ± 214 vs 363 ± 186 cc, P = .004). No difference was noted in post-op blood transfusion and drain output for 3 days in both the groups. tTXA group had lesser hospital (5.1 vs 8.9 days) and ICU length of stay (2 vs 4.2 days) and fewer immediate post-operative complications (23.5 vs 52.9%) compared to the control group but not statistically significant (P > .05). CONCLUSION: Administration of tTXA-soaked sponges is an effective and safe method to reduce intraoperative blood transfusion requirements in the correction of spinal deformity in patients with NMS.

The Approach to Pseudarthrosis After Adult Spinal Deformity Surgery: Is a Multiple-Rod Construct Necessary?

STUDY DESIGN: Retrospective study. OBJECTIVES: Our goal was to evaluate the rate of rod fracture and persistent pseudarthrosis in cohorts of patients treated with a dual rod or multiple-rod construct in revision surgery for pseudarthrosis. METHODS: A dual rod construct was used in 23 patients, and a multiple rod construct in 24 patients, spanning the pseudarthrosis level. Two-year fusion grading, and rates of pseudarthrosis and implant failure, were assessed. RESULTS: There were no differences in patient or surgical characteristics between the groups: (2- rod construct: Age 60 ± 14, Levels 10 ± 5, 3-column osteotomy:17%; multiple-rod construct: Age: 62 ± 11, Levels 9 ± 4, 3-column osteotomy:30%). Patients in the multiple rod construct were transfused a greater volume of packed red blood cells (pRBCs) intraoperatively (2.6 ± 2.9 vs. 1.1 ± 1.5 U, p < 0.0001). At 2 year follow up there was no difference in fusion grades at the previous level of pseudarthrosis, the rate of rod fracture or pseudarthrosis between the 2 groups, or rate of reoperation for pseudarthrosis, rod fracture, wound infection, hardware prominence, or PJK/PJF. CONCLUSIONS: Our data demonstrate no difference in fusion grade, or rates of rod fracture and revision at 2 years, after utilizing a dual rod versus multiple rod construct in revision surgery for pseudarthrosis. The low complication rates seen with either configuration warrant further investigation of the optimal instrumentation configuration.

Case Start Timing of Adult Spinal Deformity Surgeries: Does the Wait Matter?

BACKGROUND: Adult spinal deformity (ASD) surgery can entail complex reconstructive procedures. It is unclear whether there is any effect of case start time on outcomes. We sought to evaluate the effects of case start time and day of the week on 90-day complication, readmission, and revision rates after ASD surgery. METHODS: This is a retrospective study of 1040 ASD patients from a single institution. We collected start times and day of the week for cases from 2011 to 2018. Early start was designated as any case starting either before or at 7:30 am or between 7:30 and 11 am; late start was designated as any case starting at 11 am or later. Outcome measures include 90-day complication, revision, and readmission rates. RESULTS: A total of 1040 ASD patients (age, 46 ± 23 years; body mass index, 25 ± 7; American Society of Anesthesiologists classification, 2.5 ± 0.6; levels fused, 10 ± 4; three column osteotomy (3CO), 13%) were included. There was no association between surgery day of the week and length of stay, 90-day complication, readmission, or reoperation rates in the adjusted analyses. Late start cases had higher rates of 90-day readmission (10.5% vs 6.0%, P = 0.02), reoperation (11.9% vs 6.6%, P = 0.008), and neurologic injury (5.2% vs 2.1%, P = 0.019). Subanalysis of neurologic complications demonstrated that there was a higher rate of postoperative radiculopathy (P = 0.007) and residual central or foraminal stenosis (P = 0.029) in late start cases. A late start time was predictive of increased risk for 90-day readmission (OR 1.8, P = 0.02), unplanned reoperation (OR 1.9, P = 0.009), and neurologic complication (OR 2.1, P = 0.046). CONCLUSIONS: A late OR start time was predictive of increased risk for neurologic complication, 90-day readmission, and unplanned reoperation. The well-established protocols for first start OR times for elective ASD surgery may decrease outcome risk and reduce variability in complication rates. CLINICAL RELEVANCE: Understanding the impact of start time on outcomes and complications after ASD surgery is helpful for surgeons in preoperative planning and for institutions and hospitals' allocation of operating room staff and resources.

Pseudarthrosis and Rod Fracture Rates After Transforaminal Lumbar Interbody Fusion at the Caudal Levels of Long Constructs for Adult Spinal Deformity Surgery.

BACKGROUND: Interbody fusion at the caudal levels of long constructs for adult spinal deformity (ASD) surgery is used to promote fusion and secure a solid foundation for maintenance of deformity correction. We sought to evaluate long-term pseudarthrosis, rod fracture, and revision rates for TLIF performed at the base of a long construct for ASD. METHODS: We reviewed 316 patients who underwent TLIF as a component of ASD surgery for medical comorbidities, surgical characteristics, and rate of unplanned reoperation for pseudarthrosis or instrumentation failure at the TLIF level. Fusion grading was assessed after revision surgery for pseudarthrosis at the TLIF level. RESULTS: Rate of pseudarthrosis at the TLIF level was 9.8% (31/316), and rate of rod fractures was 7.9% (25/316). The rate of revision surgery at the TLIF level was 8.9% (28/316), and surgery was performed at a mean of 20.4 ± 16 months from the index procedure. Current smoking status (odds ratio 3.34, P = 0.037) was predictive of pseudarthrosis at the TLIF site. At a mean follow-up of 43 ± 12 months after revision surgery, all patients had achieved bony union at the TLIF site. CONCLUSIONS: At 3-year follow-up, the rate of pseudarthrosis after TLIF performed at the base of a long fusion for ASD was 9.8%, and the rate of revision surgery to address pseudarthrosis and/or rod fracture was 8.9%. All patients were successfully treated with revision interbody fusion or posterior augmentation of the fusion mass, without need for further revision procedures at the TLIF level.

Not Frail and Elderly: How Invasive Can We Go in This Different Type of Adult Spinal Deformity Patient?

STUDY DESIGN: Retrospective review of a single-center spine database. OBJECTIVE: Investigate the intersections of chronological age and physiological age via frailty to determine the influence of surgical invasiveness on patient outcomes. SUMMARY OF BACKGROUND DATA: Frailty is a well-established factor in preoperative risk stratification and prediction of postoperative outcomes. The surgical profile of operative patients with adult spinal deformity (ASD) who present as elderly and not frail (NF) has yet to be investigated. Our aim was to examine the surgical profile and outcomes of patients with ASD who were NF and elderly. METHODS: Patients with ASD 18 years or older, four or greater levels fused, with baseline (BL) and follow-up data were included. Patients were categorized by ASD frailty index: NF, Frail (F), severely frail (SF]. An elderly patient was defined as 70 years or older. Patients were grouped into NF/elderly and F/elderly. SRS-Schwab modifiers were assessed at BL and 1 year (0, +, ++). Logistic regression analysis assessed the relationship between increasing invasiveness, no reoperations, or major complications, and improvement in SRS-Schwab modifiers [Good Outcome]. Decision tree analysis assessed thresholds for an invasiveness risk/benefit cutoff point. RESULTS: A total of 598 patients with ASD included (55.3 yr, 59.7% F, 28.3 kg/m2). 29.8% of patients were older than 70 years. At BL, 51.3% of patients were NF, 37.5% F, and 11.2% SF. Sixty-sis (11%) patients were NF and elderly. About 24.2% of NF-elderly patients improved in SRS-Schwab by 1 year and had no reoperation or complication postoperatively. Binary regression analysis found a relationship between worsening SRS-Schwab, postop complication, and reoperation with invasiveness score (odds ratio: 1.056 [1.01-1.102], P = 0.011). Risk/benefit cut-off was 10 (P = 0.004). Patients below this threshold were 7.9 (2.2-28.4) times more likely to have a Good Outcome. 156 patients were elderly and F/SF with 16.7% having good outcome, with a risk/benefit cut-off point of less than 8 (4.4 [2.2-9.0], P < 0.001). CONCLUSION: Frailty status impacted the balance of surgical invasiveness relative to operative risk in an inverse manner, whereas the opposite was seen amongst elderly patients with a frailty status less than their chronologic age. Surgeons should perhaps consider incorporation of frailty status over age status when determining realignment plans in patients of advanced age.Level of Evidence: 3.

Operative versus nonoperative treatment for adult symptomatic lumbar scoliosis at 5-year follow-up: durability of outcomes and impact of treatment-related serious adverse events.

OBJECTIVE: Although short-term adult symptomatic lumbar scoliosis (ASLS) studies favor operative over nonoperative treatment, longer outcomes are critical for assessment of treatment durability, especially for operative treatment, because the majority of implant failures and nonunions present between 2 and 5 years after surgery. The objectives of this study were to assess the durability of treatment outcomes for operative versus nonoperative treatment of ASLS, to report the rates and types of associated serious adverse events (SAEs), and to determine the potential impact of treatment-related SAEs on outcomes. METHODS: The ASLS-1 (Adult Symptomatic Lumbar Scoliosis-1) trial is an NIH-sponsored multicenter prospective study to assess operative versus nonoperative ASLS treatment. Patients were 40-80 years of age and had ASLS (Cobb angle ≥ 30° and Oswestry Disability Index [ODI] ≥ 20 or Scoliosis Research Society [SRS]-22 subscore ≤ 4.0 in the Pain, Function, and/or Self-Image domains). Patients receiving operative and nonoperative treatment were compared using as-treated analysis, and the impact of related SAEs was assessed. Primary outcome measures were ODI and SRS-22. RESULTS: The 286 patients with ASLS (107 with nonoperative treatment, 179 with operative treatment) had 2-year and 5-year follow-up rates of 90% (n = 256) and 74% (n = 211), respectively. At 5 years, compared with patients treated nonoperatively, those who underwent surgery had greater improvement in ODI (mean difference -15.2 [95% CI -18.7 to -11.7]) and SRS-22 subscore (mean difference 0.63 [95% CI 0.48-0.78]) (p < 0.001), with treatment effects (TEs) exceeding the minimum detectable measurement difference (MDMD) for ODI (7) and SRS-22 subscore (0.4). TEs at 5 years remained as favorable as 2-year TEs (ODI -13.9, SRS-22 0.52). For patients in the operative group, the incidence rates of treatment-related SAEs during the first 2 years and 2-5 years after surgery were 22.38 and 8.17 per 100 person-years, respectively. At 5 years, patients in the operative group who had 1 treatment-related SAE still had significantly greater improvement, with TEs (ODI -12.2, SRS-22 0.53; p < 0.001) exceeding the MDMD. Twelve patients who received surgery and who had 2 or more treatment-related SAEs had greater improvement than nonsurgically treated patients based on ODI (TE -8.34, p = 0.017) and SRS-22 (TE 0.32, p = 0.029), but the SRS-22 TE did not exceed the MDMD. CONCLUSIONS: The significantly greater improvement of operative versus nonoperative treatment for ASLS at 2 years was durably maintained at the 5-year follow-up. Patients in the operative cohort with a treatment-related SAE still had greater improvement than patients in the nonoperative cohort. These findings have important implications for patient counseling and future cost-effectiveness assessments.

The Ankle-Pelvic Angle (APA) and Global Lower Extremity Angle (GLA): Summary Measurements of Pelvic and Lower Extremity Compensation.

BACKGROUND: Adult sagittal spinal deformity (SSD) leads to the recruitment of compensatory mechanisms to maintain standing balance. After regional spinal compensation is exhausted, lower extremity compensation is recruited. Knee flexion, ankle flexion, and sacrofemoral angle increase to drive pelvic shift posterior and increase pelvic tilt. We aim to describe 2 summary angles termed ankle-pelvic angle (APA) and global lower extremity angle (GLA) that incorporate all aspects of lower extremity and pelvic compensation in a comprehensive measurement that can simplify radiographic analysis. METHODS: Full-body sagittal stereotactic radiographs were retrospectively collected and digitally analyzed. Spinal and lower extremity alignment were quantified with existing measures. Two angles-APA and GLA-were drawn as geometrically complementary angles to T1-pelvic angle (TPA) and global sagittal axis (GSA), respectively. Regression analysis was used to represent the predictive relationship between TPA and APA and between GSA and GLA. RESULTS: A total of 518 propensity score-matched patient records were available for analysis. Patients with lower extremity compensation had higher APA (21.83° versus 19.47°, P = .007) and GLA (6.03° versus 1.19°, P < .001) than those without compensation. APA and GLA demonstrated strong correlation with TPA (r = 0.81) and GSA (r = 0.77), respectively. Furthermore, the change between preoperative and postoperative values were strongly correlative between ΔAPA and ΔTPA (r = 0.71) and between ΔGLA and ΔGSA (r = 0.77). APA above 20.6° and GLA above 3.6° were indicative of lower extremity compensation. Patients with increased GLA values had significantly higher Oswestry Disability Index scores (48.67 versus 41.04, P = .005). CONCLUSIONS: TPA and GSA are measures of global spinal alignment and APA and GLA, respectively, and are geometrically complementary angles that vary proportionately to SSD and balance the body. APA and GLA increase in SSD patients with lower extremity compensation and decrease with corrective surgery. LEVEL OF EVIDENCE: 4. CLINICAL RELEVANCE: APA and GLA offer a concise and simple method of communicating pelvic and lower extremity compensation.

Complications After Adult Spinal Deformity Surgeries: All Are Not Created Equal.

BACKGROUND: Data on timing of complications are important for accurate quality assessments. We sought to better define pre- and postdischarge complications occurring within 90 days of adult spinal deformity (ASD) surgery and quantify the effect of multiple complications on recovery. METHODS: We performed a review of 1040 patients who underwent ASD surgery (age: 46 ± 23; body mass index: 25 ± 7, American Society of Anesthesiologists [ASA] score: 2.5 ± 0.6, levels: 10 ± 4, revision: 9%, 3-column osteotomy: 13%). We assessed pre- and postdischarge complications and risk factors for isolated versus multiple complications, as well as the impact of multiple complications. RESULTS: The 90-day complication rate was 17.7%. 85 patients (8.2%) developed a predischarge complication, most commonly ileus (12%), and pulmonary embolism (PE; 7.1%). The most common causes of predischarge unplanned reoperation were neurologic injury (12.9%) and surgical site drainage (8.2%). Predictors of a predischarge complication included smoking (odds ratio [OR]: 2.2, P = .02), higher ASA (OR: 1.8, P = .008), hypertension (HTN; OR: 2.0, P = .004), and iliac fixation (OR: 4.3, P < .001). Ninety-nine patients (9.5%) developed a postdischarge complication, most commonly infection (34%), instrumentation failure (13.4%), and proximal junctional failure (10.4%). Predictors of postdischarge complications included chronic obstructive pulmonary disease (OR: 3.6, P < .0001), congestive heart failure (OR: 4.4, P = .016), HTN (OR: 2.3, P < .0001), and multiple rod construct (OR: 1.8, P = .02). Patients who developed multiple complications (9.3%) had a longer length of stay, and increased risk for readmission and unplanned reoperation. CONCLUSIONS: Knowledge regarding timing of postoperative complications in relation to discharge may better inform quality improvement measures. PE and implant-related complications play a prominent role in perioperative complications and need for readmission, with several modifiable risk factors identified. LEVEL OF EVIDENCE: Level 3. CLINICAL RELEVANCE: Advances in surgical techniques and instrumentation have improved postoperative radiographic and clinical outcomes after ASD surgery. The rate of complications after complex ASD surgery remains high, both at early postoperative and long term follow-up. This study reviews complications within 90 days of surgery, with an assessment of patient and surgical risk factors. We found that modifiable risk factors for early complications after ASD surgery include COPD, and current smoking. The data presented in this study also provide surgeons with knowledge of the most common complications encountered after ASD surgery, to aid in preoperative patient discussion.

Topical tranexemic acid reduces intra-operative blood loss and transfusion requirements in spinal deformity correction in patients with adolescent idiopathic scoliosis.

PURPOSE: To evaluate the effectiveness of the use of topical tranexamic acid (tTXA) in spinal deformity correction in AIS patients METHODS: Sixty consecutive operative AIS patients were reviewed from a single institution and divided into two groups with similar demographics. Standardized peri-operative blood salvage techniques were utilized in all 60 patients. In the latter 30 patients, tTXA soaked sponges (1 g mixed in 500 ml Normal Saline) was utilised for wound packing during the entire surgical procedure compared to dry sponges as used in the former 30 patients. Both the groups were compared for the magnitude of deformity corrected, EBL per level fused, total EBL, blood transfused, drain output and peri-operative events. RESULTS: Sixty AIS patients (mean age 14.4 yrs, 43 females, mean BMI 21.5, mean levels 10.7) were included. Both groups achieved similar change in Coronal Cobb correction. The EBVL (Estimated blood volume loss) % lost in the topical TXA group was 38% less than the control group (11.2 vs. 18.3%, p = 0.006). Similarly, the EBL/level was significantly lower in the topical TXA group (41 ± 30 ml vs. 57 ± 26 ml, p = 0.03). Three of 30 patients in the control group required at least 1 unit of blood transfusion, whereas only 1 patient in the topical TXA group required transfusion (10 vs. 3.3%, p = 0.001). No differences were noted in post-operative drain output, change in hemoglobin levels, and peri-operative complication rates. CONCLUSION: When used as an adjunct to the conventional blood salvage techniques in spinal deformity correction procedures, the use of tTXA resulted in reduced operative blood loss, and blood transfusion requirements.

A Focused Gap Year Program in Orthopaedic Research: An 18-Year Experience.

INTRODUCTION: Students seek gap years to enhance knowledge and improve chances of professional success. Although many institutions offer research opportunities, no studies have examined outcomes after these experiences. This study evaluates a dedicated year of orthopaedic research on a cohort's ultimate orthopaedic surgery match rate. METHODS: From 2001 to 2018, 129 learners spent a year with our Department of Orthopedic Surgery at a major academic medical center. The students were either completing a gap year after college, during or after medical school, or after an unsuccessful match. Participants were asked to respond to a survey, which included demographics, educational information, and metrics related to the program. For the subcohort of students who ranked orthopaedic surgery, the match rate was compared with the mean for the US orthopaedic surgery match rates from 2006 to 2018 using a chi-square analysis. In addition, a Mann-Whitney U test was used to compare the number of publications before and after the year. RESULTS: One hundred three students (80%) returned completed questionnaires. Of all learners who applied to and ranked orthopaedic surgery, 91% matched into an orthopaedic surgery residency program. These results compared favorably with the US orthopaedic match from 2006 to 2018 (67.9%; P < 0.001), despite a 4-point lower United States Medical Licensing Examination (USMLE) Step 1 score for the research cohort. Finally, the research cohort had a greater percentage of women (23%) and minorities (40%) than the proportion of woman and minority practicing orthopaedic surgeons. CONCLUSION: Students who completed a gap year in research matched into orthopaedics at a higher rate than the national average, despite a lower Step score. Mentors may also target traditionally underrepresented groups to help increase the pool of diverse applicants.

Mandibular slope: a reproducible and simple measure of horizontal gaze.

STUDY DESIGN: This study is a single-center retrospective radiographic review. OBJECTIVES: The objective of this study is to evaluate a novel measurement parameter, mandibular slope (MS), as a measure of horizontal gaze. INTRODUCTION: Assessment of sagittal spinal alignment is essential in the evaluation of spinal deformity patients. Ability to achieve a horizontal gaze, a parameter of sagittal alignment, is needed for the performance of daily activities. Standard measures of horizontal gaze, including the gold-standard chin-brow to vertical angle (CBVA) and the surrogate measures McGregor's line (McGS) and Chamberlain's line (CS), require high-quality imaging, precise head positioning, and reliance on difficult to view visual landmarks. A novel measurement parameter, MS, utilizing the caudal margin of the mandible on standard lateral spine radiographs is proposed. METHODS: 90 radiographs from spine deformity patients with or without spinal implants from a single center were evaluated. Three spine surgery fellows independently measured CBVA, McGS, CS, and MS at two timepoints at least one week apart to assess accuracy and reliability. MS was measured as the angle created by the inferior edge of the mandibular body and the horizontal. Formulas for calculating CBVA based on the above parameters were derived and compared to the actual CBVA. RESULTS: Mean age was 49.7 years, 76 females and 14 males. CBVA correlated with CS, McGS, and MS, r = 0.85, 0.81, and 0.80, respectively (p < 0.001). Standard error between real CBVA and calculated CBVA using CS (0.4 ± 4.79) and McGS (0.4 ± 3.9) was higher than that calculated using MS (- 0.2 ± 4.3). ICC demonstrated the highest inter-observer reliability with MS (0.999). MS had the highest intra-observer reliabilities 0.975, 0.981, and 0.988 (p < 0.001); CS and McGS also demonstrated high intra-observer reliability. CONCLUSIONS: MS is a promising measure of horizontal gaze that correlates highly with CBVA, has excellent intra- and inter-observer reliability with CBVA, and is easily measured using standard lateral spine radiographs.

Efficacy of intraoperative cell salvage in spine surgery: a meta-analysis.

OBJECTIVE: Intraoperative cell salvage systems, or cell savers, are widely used for the management of blood loss in patients undergoing spine surgery. However, recent studies report conflicting evidence of their efficacy. The purpose of the meta-analysis was to investigate the efficacy of cell savers in reducing blood transfusion requirements in patients undergoing spine surgery. METHODS: Both retrospective and prospective studies that investigated the efficacy of cell savers in reducing transfusion requirements in spine surgery patients when compared with control patients were identified from MEDLINE, Embase, Cochrane Collaboration Library, Google Scholar, and Scopus databases. Outcome data extracted included number of patients receiving allogenic transfusions (transfusion rate); units of allogenic transfusions; postoperative hemoglobin; costs; operative time; and complications. RevMan 5 software was used to perform statistical analyses. A random-effects model was used to calculate pooled odds ratios (with 95% CIs) and weighted mean differences (WMDs [95% CI]) for dichotomous and continuous variables, respectively. RESULTS: Eighteen studies with 2815 patients in total were included in the meta-analysis. During spine surgery, the use of intraoperative cell salvage did not reduce the intraoperative (OR 0.66 [95% CI 0.30, 1.41]), postoperative (OR -0.57 [95% CI 0.20, 1.59]), or total transfusion (OR 0.92 [95% CI 0.43, 1.98]) rate. There was a reduction in the number of allogenic units transfused intraoperatively by a mean of 0.81 (95% CI -1.15, -0.48). However, there were no differences in the number of units transfused postoperatively (WMD -0.02 [95% CI -0.41, 0.38]) or the total units transfused (WMD 0.08 [95% CI -1.06, 1.22]). There were also no differences in operative time (WMD 19.36 [95% CI -2.43, 42.15]) or complications reported (OR 0.79 [95% CI 0.46, 1.37]) between groups. A difference in postoperative hemoglobin (WMD 0.54 [95% CI 0.11, 0.98]) between both groups was observed. CONCLUSIONS: Cell saver is efficacious at reducing intraoperative allogenic units transfused. There is no difference in transfusion rates, postoperative units transfused, and the total number of units transfused. Further cost analysis studies are necessary to evaluate the cost-effectiveness of this method of blood conservation.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: meta-analysis; strength of recommendation: low.

Prevalence of Risk Factors for Hospital-Acquired Venous Thromboembolism in Neurosurgery and Orthopedic Spine Surgery Patients.

BACKGROUND: Hospital-acquired venous thromboembolisms (HA-VTE) are a significant source of morbidity and mortality in spine surgery patients. The purpose of this study was to review HA-VTE rates at our institution and evaluate the prevalence of known risk factors in patients who developed HA-VTE among both neurosurgical and orthopedic spine surgeries. METHODS: Retrospective chart reviews were conducted of all spine surgery patients from January 1, 2013, to July 31, 2017, to evaluate rates of HA-VTE and prevalence of known HA-VTE risk factors among these patients. Univariate and multivariate logistic regression analysis for categorical variables and independent Student t test for continuous variables were utilized with significance set at P < .05. RESULTS: The overall HA-VTE rate was 0.94% (0.61% orthopedic, 1.87% neurosurgery). Patients with VTEs had higher rates of thoracic procedure (P = .002), posterior approach (P = .001), diagnosis of fracture (P = .013) or flatback syndrome (P = .028), neurosurgery division (P < .001), and diagnosis-related group (DRG) of noncervical malignancy (P = .001). Patients with VTEs had lower rates of cervical procedure (P < .001), diagnosis of herniated nucleus pulposus (P = .006) and degenerative disc disease (P = .001), and DRG of cervical spine fusion (P < .001). In the patients who sustained VTE, the neurosurgical patients had higher rates of active cancer (22.86% vs 0%, P = .004) and age >60 (80% vs 50%, P < .001), and orthopedic patients had higher estimated blood loss (EBL) (2436 ml vs 1176 mL, P = .006) and rates of anterior-posterior surgery (22.58% vs 0%, P = .003). Neurosurgery department, diagnosis of fracture, and DRG of noncervical malignancy were found to be significant independent risks for developing HA-VTE. Cervical procedures were independently associated with significantly lower risk. Postoperative anticoagulation initiated sooner in neurosurgery patients (postoperative day 1.26 vs 3.19, P < .001). CONCLUSIONS: The overall HA-VTE rate at our institution was 0.94% (0.61% orthopedic, 1.87% neurosurgery). In patients who sustained VTE, neurosurgical patients had higher rates of active cancer and age >60 years, and orthopedic patients had higher EBL and rates of anterior-posterior surgery. This highlights the different patient populations between the 2 departments and the need for individualized thromboprophylaxis regimens. LEVEL OF EVIDENCE: 4.

Decision Tree-based Modelling for Identification of Predictors of Blood Loss and Transfusion Requirement After Adult Spinal Deformity Surgery.

BACKGROUND: Multilevel fusions and complex osteotomies to restore global alignment in adult spinal deformity (ASD) surgery can lead to increased operative time and blood loss. In this regard, we assessed factors predictive of perioperative blood product transfusion in patients undergoing long posterior spinal fusion for ASD. METHODS: A single-institution retrospective review was conducted on 909 patients with ASD, age > 18 years, who underwent surgery for ASD with greater than 4 levels fused. Using conditional inference tree analysis, a machine learning methodology, we sought to predict the combination of variables that best predicted increased risk for intraoperative percent blood volume lost and perioperative blood product transfusion. RESULTS: Among the 909 patients included in the study, 377 (41.5%) received red blood cell (RBC) transfusion. The conditional inference tree analysis identified greater than 13 levels fused, American Society of Anesthesiologists (ASA) score > 1, a history of hypertension, 3-column osteotomy, pelvic fixation, and operative time > 8 hours, as significant risk factors for perioperative RBC transfusion. The best predictors for the subgroup with the highest risk for intraoperative percent blood volume lost (subgroup mean: 53.1% ± 42.9%) were greater than 13 levels fused, ASA score > 1, preoperative hemoglobin < 13.6 g/dL, 3-column osteotomy, posterior column osteotomy, and pelvic fixation. Patients who underwent major blood transfusion intraoperatively had significantly longer length of stay (8.5 days) versus those who did not (6.1 days) (P < .0001). The overall 90-day complication rate in patients who underwent major blood transfusion intraoperatively was 49%, compared with 19% in those who did not (P < .0001). By multivariate regression analysis, patients with a preoperative hemoglobin > 13.0 were less likely to require major blood transfusion (odds ratio: 0.52, P = .046). CONCLUSIONS: Using a supervised learning technique, this study demonstrates that greater than 13 levels fused, ASA score > 1, 3-column osteotomy, and pelvic fixation are consistent risk factors for increased intraoperative percent blood volume lost and perioperative RBC transfusion. The addition of having a preoperative hemoglobin < 13.6 g/dL or undergoing a posterior column osteotomy conferred the highest risk for intraoperative blood loss. This information can assist spinal deformity surgeons in identifying at-risk individuals and allocating healthcare resources. LEVEL OF EVIDENCE: 3.

MRI Radiological Predictors of Requiring Microscopic Lumbar Discectomy After Lumbar Disc Herniation.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate radiological differences in lumbar disc herniations (herniated nucleus pulposus [HNP]) between patients receiving microscopic lumbar discectomy (MLD) and nonoperative patients. METHODS: Patients with primary treatment for an HNP at a single academic institution between November 2012 to March 2017 were divided into MLD and nonoperative treatment groups. Using magnetic resonance imaging (MRI), axial HNP area; axial canal area; HNP canal compromise; HNP cephalad/caudal migration and HNP MRI signal (black, gray, or mixed) were measured. T test and chi-square analyses compared differences in the groups, binary logistic regression analysis determined odds ratios (ORs), and decision tree analysis compared the cutoff values for risk factors. RESULTS: A total of 285 patients (78 MLD, 207 nonoperative) were included. Risk factors for MLD treatment included larger axial HNP area (P < .01, OR = 1.01), caudal migration, and migration magnitude (P < .05, OR = 1.90; P < .01, OR = 1.14), and gray HNP MRI signal (P < .01, OR = 5.42). Cutoff values for risks included axial HNP area (70.52 mm2, OR = 2.66, P < .01), HNP canal compromise (20.0%, OR = 3.29, P < .01), and cephalad/caudal migration (6.8 mm, OR = 2.43, P < .01). MLD risk for those with gray HNP MRI signal (67.6% alone) increased when combined with axial HNP area >70.52 mm2 (75.5%, P = .01) and HNP canal compromise >20.0% (71.1%, P = .05) cutoffs. MLD risk in patients with cephalad/caudal migration >6.8 mm (40.5% alone) increased when combined with axial HNP area and HNP canal compromise (52.4%, 50%; P < .01). CONCLUSION: Patients who underwent MLD treatment had significantly different axial HNP area, frequency of caudal migration, magnitude of cephalad/caudal migration, and disc herniation MRI signal compared to patients with nonoperative treatment.

Static and Dynamic Balance in Adults Undergoing Lumbar Spine Surgery: Screening and Prediction of Postsurgical Outcomes.

INTRODUCTION: Balance and fall risk before and after lumbar surgery was assessed to determine whether balance at baseline predicts long-term postsurgical outcomes. METHODS: Forty-three patients in the United States and Israel performed the single-leg stance (SLS) test, four square step test (FSST), and 8-foot up-and-go (8FUG) test before and 2 to 4 months after lumbar spine surgery. They completed the Oswestry Disability Index (ODI) and pain rating before and 12 months after lumbar surgery. RESULTS: From baseline to follow-up, the SLS time was 3.74 seconds longer (P = 0.01), the FSST time was 1.94 seconds faster (P < 0.001), and the 8FUG time was 1.55 seconds faster (P = 0.02). Before surgery, 26% of the patients were considered high fall risk according to the FSST and 51% according to the 8FUG. Postsurgery, all patients could complete the physical tests, but 26% remained at high fall risk according to the 8FUG and 7.5% according to the FSST. The three physical measures together explained 30% of the variance in postsurgical ODI scores (P = 0.02). Age was not correlated with performance. DISCUSSION: Risk of falling is higher than surgeons suspect. Balance tests (ie, SLS, FSST, and 8FUG) are quick and easy to administer. The findings support the importance of screening for balance and fall risk in adults undergoing lumbar spine surgery.

Use of a Novel Computerized Drill for Pedicle Screw Insertion in the Thoracic and Lumbar Spine: A Cadaveric Study.

BACKGROUND: A variety of techniques have been utilized to improve the accuracy of pedicle screw instrumentation. Recently, a novel handheld computerized drill system, IntelliSense Drill Technology, has been used in orthopedic trauma to improve drilling accuracy and reduce radiation and iatrogenic injury. The specialized drill technology detects changes in cortical density to prevent inadvertent cortical violation. The aim of this study is to assess the ability of this system to identify pedicle trajectories in the thoracic and lumbar spine compared to a standard freehand technique. METHODS: Two spine surgeons, including 1 senior-level and 1 junior-level attending drilled pedicle screw tracts using a freehand technique and computerized drill technology in 4 cadaveric spines from T2 to S1. A total of 134 pedicle screws were placed, including 70 by the senior surgeon and 64 by the junior surgeon. Cortical violations were assessed using computed tomography after instrumenting each pedicle tract, and procedure time for insertion of pedicle screws was recorded. RESULTS: A total of 15 (22.4%) and 12 (18.2%) pedicle violations were noted using the freehand and computerized drill technique, respectively (P = .767). Perforations using the computerized drill decreased from 31.1% in the first attempt to 5.9% in the second attempt (P = .027). Mean drill time per pedicle using the freehand and computerized drill techniques were comparable (12.2 ± 8.4 versus 12.1 ± 13.2, P = .871), and both surgeons had an improvement in procedure time using the computerized drill (surgeon 1: 12.3 ± 13.7-5.7 ± 3.8 [SD], P = .059; surgeon 2: 20.3 ± 20.0-10.4 ± 5.6 [SD], P = .063). CONCLUSIONS: We demonstrate the use of a novel drill technology for placement of pedicle screws in the thoracic and lumbar spine. After an initial learning curve, this technology is comparable to use of a freehand technique by both a senior-level and a junior-level attending surgeon in a cadaveric model. Further investigation is needed to identify the clinical role of this technology in spine surgery.

Congenital Etiology Is an Independent Risk Factor for Complications in Adolescents Undergoing Corrective Scoliosis Surgery: Comparison of In-hospital Comorbidities Using Nationwide KID's Inpatient Database.

BACKGROUND: Congenital scoliosis (CS) is associated with more rigid, complex deformities relative to adolescent idiopathic scoliosis (AIS) which theoretically increases surgical complications. Despite extensive literature studying AIS patients, few studies have been performed on CS patients. The purpose of this study was to evaluate complications associated with spinal fusions for CS and AIS. METHODS: A retrospective review of the Kid's Inpatient Database (KID) years 2000 to 2009 was performed. Inclusion: patients under 20 years with ICD-9 diagnosis codes for idiopathic scoliosis (IS-without concomitant congenital anomalies) and CS, undergoing spinal fusion from the KID years 2000 to 2009. Two analyses were performed according to age below 10 years and 10 years and above. Univariate analysis described differences in demographics, comorbidities, intraoperative complications, and clinical values between groups. Binary logistic regression controlling for age, sex, race, and invasiveness predicted complications risk in CS (odds ratios; 95% confidence interval). RESULTS: In total, 25,131 patients included (IS, n=22443; CS, n=2688). For patients under age 10, CS patients underwent 1 level shorter fusions (P<0.001), had fewer comorbidities (P<0.001), and sustained similar complication incidence. In the 10 and over age analysis, CS patients similarly had shorter fusions, but greater comorbidities, and significantly more complications (odds ratio, 1.6; confidence interval, 1.4-1.8). CONCLUSIONS: CS patients have higher in-hospital complication rates. With more comorbidities, these patients have increased risk of sustaining procedure-related complications such as shock, infection, and Adult Respiratory Distress Syndrome. These data help to counsel patients and their families before spinal fusion. LEVEL OF EVIDENCE: Level III-retrospective review of a prospectively collected database.

Incidence of Congenital Spinal Abnormalities Among Pediatric Patients and Their Association With Scoliosis and Systemic Anomalies.

BACKGROUND: Congenital abnormalities when present, according to VACTERL theory, occur nonrandomly with other congenital anomalies. This study estimates the prevalence of congenital spinal anomalies, and their concurrence with other systemic anomalies. METHODS: A retrospective cohort analysis on Health care Cost and Utilization Project's Kids Inpatient Database (KID), years 2000, 2003, 2006, 2009 was performed. ICD-9 coding identified congenital anomalies of the spine and other body systems. OUTCOME MEASURES: Overall incidence of congenital spinal abnormalities in pediatric patients, and the concurrence of spinal anomaly diagnoses with other organ system anomalies. Frequencies of congenital spine anomalies were estimated using KID hospital-and-year-adjusted weights. Poisson distribution in contingency tables tabulated concurrence of other congenital anomalies, grouped by body system. RESULTS: Of 12,039,432 patients, rates per 100,000 cases were: 9.1 hemivertebra, 4.3 Klippel-Fiel, 56.3 Chiari malformation, 52.6 tethered cord, 83.4 spina bifida, 1.2 absence of vertebra, and 6.2 diastematomyelia. Diastematomyelia had the highest concurrence of other anomalies: 70.1% of diastematomyelia patients had at least one other congenital anomaly. Next, 63.2% of hemivertebra, and 35.2% of Klippel-Fiel patients had concurrent anomalies. Of the other systems deformities cooccuring, cardiac system had the highest concurrent incidence (6.5% overall). In light of VACTERL's definition of a patient being diagnosed with at least 3 VACTERL anomalies, hemivertebra patients had the highest cooccurrence of ≥3 anomalies (31.3%). With detailed analysis of hemivertebra patients, secundum ASD (14.49%), atresia of large intestine (10.2%), renal agenesis (7.43%) frequently cooccured. CONCLUSIONS: Congenital abnormalities of the spine are associated with serious systemic anomalies that may have delayed presentations. These patients continue to be at a very high, and maybe higher than previously thought, risk for comorbidities that can cause devastating perioperative complications if not detected preoperatively, and full MRI workups should be considered in all patients with spinal abnormalities. LEVEL OF EVIDENCE: Level III.

Minimally Invasive Versus Open Transforaminal Lumbar Interbody Fusion Surgery: An Analysis of Opioids, Nonopioid Analgesics, and Perioperative Characteristics.

STUDY DESIGN: Retrospective study of consecutive patients at a single institution.Objective: Examine the effect of minimally invasive surgery (MIS) versus open transforaminal lumbar interbody fusion (TLIF) surgery on long-term postoperative narcotic consumption. OBJECTIVE: Examine the effect of minimally invasive versus open TLIF on short-term postoperative narcotic consumption. METHODS: Differences between MIS and open TLIF, including inpatient opioid and nonopioid analgesic use, discharge opioid use, and postdischarge duration of narcotic usage were compared using appropriate statistical methods. RESULTS: A total of 172 patients (109 open; 63 MIS) underwent primary TLIF. There was no difference in baseline characteristics. The MIS TLIF cohort had a significantly shorter operative time (223 vs 251 min, P = .006) and length of stay (2.7 vs 3.7 days, P < .001) as well as less estimated blood loss (184 vs 648 mL, P < .001). MIS TLIF had significantly less total inpatient opioid usage (167 vs 255 morphine milligram equivalent [MME], P = .006) and inpatient oxycodone usage (71 vs 105 mg, P = .049). Open TLIF cases required more ongoing opiate usage at 3-month follow-up (36% open vs 21% MIS, P = .041). A subanalysis found that patients who underwent an open TLIF with a history of preoperative opioid use are significantly more likely to remain on opioids at 6-week follow-up (87% vs 65%, P = .027), 3-month follow-up (63% vs 31%, P = .008), and 6-month follow-up (50% vs 21%, P = .018) compared with MIS TLIF. CONCLUSION: Patients undergoing MIS TLIF required less inpatient opioids and had a decreased incidence of opioid dependence at 3-month follow-up. Patients with preoperative opioid use undergoing MIS TLIF are less likely to require long-term opioids.