Instrumented Spinal Fusion Research Articles

Failure of an expandable lumbar interbody spacer - a critical analysis of secondary collapse, pseudoarthrosis and revision rates after thoracolumbar fusion.

To report on the failure rates of an expandable interbody spacer, used for spinal instrumented transforaminal lumbar interbody fusion (TLIF) or posterior thoracolumbar interbody fusion (PLIF). In this retrospective, single-center observational cohort study we reviewed consecutive PLIF/TLIF patients using the Catalyft™ PL and PL40 expandable titanium interbody implant (Medtronic, Minneapolis (USA)) between 07/2022 and 11/2023. We recorded patient demographics, surgical parameters, adverse events, radiological parameters and clinical outcomes according to the MacNab criteria. We identified 53 patients (mean age 68.6 ± 11.5 years; 49.1% female; mean BMI 25.7 ± 4.4kg/m2), in which 92 Catalyft™ spacers were implanted, mostly at L4/5 (n = 35; 38.0%) and L5/S1 (n = 31; 33.7%) for degenerative (n = 44; 83.0%), deformity (n = 7; 13.2%) or other indications (n = 2; 3.8%). We noticed secondary collapse of 20 (21.7%) spacers in 11 patients (20.7%) occurring after a mean time of 4.0 ± 4.1 months postoperatively. Age < 70 years was identified as risk factor for secondary collapse (OR 3.71, 95% CI 1.31-10.5, p = 0.014), but no association was found regarding other patient-specific or surgery-related variables. Pseudarthrosis was evident in seven patients (13.2%), of which four (7.6%) required revision surgery. Clinical outcome at last follow-up (mean 6.4 ± 4.2 months) was excellent/good in 29 (54.7%), fair in 14 (26.4%) and poor in six patients (11.3%). We provide a critical analysis of our series of patients with use of a specific type of expandable interbody spacer. We noticed failure and secondary collapse in an unacceptably high number of implants, some of which required revision surgery.

The impact of closed suction wound drainage on chronic pain and health-related quality of life after posterior spinal fusion in patients with adolescent idiopathic scoliosis.

Closed suction subfascial drainage is widely used after instrumented posterior spinal fusion in patients with a spinal deformity. The aim of this study was to determine the effect of this wound drainage on the outcomes in patients with adolescent idiopathic scoliosis (AIS). This was a further analysis of a randomized, multicentre clinical trial reporting on patients after posterior spinal fusion using segmental pedicle screw instrumentation. In this study the incidence of deep surgical site infection (SSI) and chronic postoperative pain at two years' follow-up are reported. We conducted a randomized, multicentre clinical trial on adolescents undergoing posterior spinal fusion for AIS using segmental pedicle screw instrumentation. A total of 90 consecutive patients were randomized into a 'drain' or 'no drain' group at the time of wound closure, using the sealed envelope technique (1:1). The primary outcomes in the initial study were the change in the level of haemoglobin in the blood postoperatively and total blood loss. A secondary outcome was the opioid consumption immediately after surgery. The aim of this further study was to report the rate of deep SSI and persistent postoperative pain, at two years' follow-up. As previously reported, the mean 48-hour opioid consumption was significantly higher in the no drain group (2.0 mg/kg (SD 0.8) vs 1.4 mg/kg (SD 0.7); p = 0.005). There were no delayed deep SSIs. At two years' follow-up, the mean Scoliosis Research Society 24-item questionnaire (SRS-24) total score did not differ between the groups (4.11 (SD 0.47) vs 4.16 (SD 0.33); p = 0.910). The mean SRS-24 pain score was 4.28 (SD 0.48) in the no drain group compared with 4.33 (SD 0.66) in the drain group (p = 0.245). Seven patients (19%) in the no drain group and six in the drain group (14%) reported moderate to severe pain (numerical rating scale ≥ 4) at two years' follow-up (p = 0.484). The general self-image domain score was significantly higher in the no drain group compared with the drain group (4.02 (SD 0.74) vs 4.59 (SD 0.54); p < 0.001). The main finding in this study was that more severe pain immediately after surgery did not result in a higher incidence of chronic pain in the no drain group compared with the drain group. Back pain and health-related quality of life at two years' follow-up did not differ between the groups. The patient-reported self-image domain was significantly better in the no drain group compared with the drain group.

Machine learning approach to predict acute kidney injury among patients undergoing multi-level spinal posterior instrumented fusion.

Acute kidney injury (AKI) after spinal fusion is a significant morbidity that can lead to poor post-surgical outcomes. Identifying AKI risk factors and developing a risk model can raise surgeons' awareness and allow them to take actions to mitigate the risks. The objective of the current study is to develop machine learning (ML) models to assess patient risk factors predisposing to AKI after posterior spinal instrumented fusion. Data was collected from the IBM MarketScan Database (2009-2021) for patients >18 years old who underwent spinal fusion with posterior instrumentation (3-6 levels). AKI incidence (defined by the International Classification of Diseases codes) was recorded 90-day post-surgery. Risk factors for AKI were investigated and compared through several ML models including logistic regression, linear support vector machine (LSVM), random forest, extreme gradient boosting (XGBoost), and neural networks. Among the 141,697 patients who underwent fusion with posterior instrumentation (3-6 levels), the overall rate of 90-day AKI was 2.96%. We discovered that the logistic regression model and LSVM demonstrated the best predictions with area under the curve (AUC) values of 0.75. The most important AKI prediction features included chronic renal disease, hypertension, diabetes mellitus ± complications, older age (>50 years old), and congestive heart failure. Patients who did not have these five key risk factors had a 90-day AKI rate of 0.29%. Patients who had an increasing number of key risk factors subsequently had higher risks of postoperative AKI. The analysis of the data with different ML models identified 5 key variables that are most closely associated with AKI: chronic renal disease, hypertension, diabetes mellitus ± complications, older age (>50 years old), and congestive heart failure. These variables constitute a simple risk calculator with additive odds ratio ranging from 3.38 (1 risk factor) to 91.10 (5 risk factors) over 90 days after posterior spinal fusion surgery. These findings can help surgeons risk-stratify their patients for AKI risk, and potentially guide post-operative monitoring and medical management.

Risk Factors for Sacroiliac Joint Fusion after Instrumented Spinal Fusion.

Retrospective Cohort Study. To identify risk factors for sacroiliac (SI) joint fusion after instrumented spinal fusion. Patients were identified from the PearlDiver BiscayneBay database. Patients who underwent 1 level (CPT: 22840), 3-6 vertebral segment (22842), and 7+ vertebral segment spinal fusions (22843 and 22844) were identified. Patients were separated based on whether they received an SI joint fusion (27280 and 27279) after their spinal fusion. A univariate analysis and multivariate logistic regression was performed to evaluate the associations between patient factors and incidence of SI joint fusion. 549,625 patients who underwent posterior spinal fusions were identified, 6068 of whom underwent subsequent SI joint fusion (1.1%). Factors associated with future SI joint fusion included female gender, patients with obesity, fibromyalgia, diabetes, tobacco use, increased construct length, and prior SI joint injection. Prior SI joint injection had the highest odds ratio (OR: 8.70; 95% CI: 8.25-9.16; P < 0.001), followed by 7+ vertebral segment (OR: 2.17; 95% CI: 2.03-2.33; P < 0.001) and 3-6 vertebral segment fusion (OR: 1.49; 95% CI: 1.42-1.57; P < 0.001). The highest predictor of requiring subsequent SI joint fusion is a prior SI joint injection. We also found that longer fusion constructs are associated with increased risk for future SI joint fusion.

Anatomically and mechanically conforming patient-specific spinal fusion cages designed by full-scale topology optimization

Cage subsidence after instrumented lumbar spinal fusion surgery remains a significant cause of treatment failure, specifically for posterior or transforaminal lumbar interbody fusion. Recent advancements in computational techniques and additive manufacturing, have enabled the development of patient-specific implants and implant optimization to specific functional targets. This study aimed to introduce a novel full-scale topology optimization formulation that takes the structural response of the adjacent bone structures into account in the optimization process. The formulation includes maximum and minimum principal strain constraints that lower strain concentrations in the adjacent vertebrae. This optimization approach resulted in anatomically and mechanically conforming spinal fusion cages. Subsidence risk was quantified in a commercial finite element solver for off-the-shelf, anatomically conforming and the optimized cages, in two representative patients. We demonstrated that the anatomically and mechanically conforming cages reduced subsidence risk by 91% compared to an off-the-shelf implant with the same footprint for a patient with normal bone quality and 54% for a patient with osteopenia. Prototypes of the optimized cage were additively manufactured and mechanically tested to evaluate the manufacturability and integrity of the design and to validate the finite element model.

Is Next-day Discharge Safe After Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis?

While the implementation of enhanced recovery after surgery protocols and improvements in pain control have decreased the length of stay (LOS) after scoliosis surgery, adolescents are typically hospitalized for several days after posterior spinal instrumented fusion (PSF). The purpose of this study was to determine whether next-day discharge after PSF for adolescent idiopathic scoliosis (AIS) had an equivalent safety profile compared with longer LOS. The secondary purpose was to examine perioperative factors associated with next-day discharge. We performed a retrospective study of all patients who underwent PSF for AIS at a single institution from 2017 to 2022. We compared patients based on postoperative LOS with an early discharge group consisting of those who were discharged on the first postoperative day 1 (POD1; n = 40) and a standard discharge group consisting of those who were discharged after POD1 (n = 71). We documented preoperative variables, including patient demographics and curve characteristics, intraoperative variables, including levels fused, implant density, operative time, and blood loss, and postoperative variables, including emergency department (ED) visits within 30 days and hospital readmissions within 90 days. One hundred eleven patients were included with a mean curve magnitude of 67 degrees. Forty patients (36%) were discharged on POD1. There were one (3%) ED visit and 2 (5%) readmissions in the early discharge group and 3 (4%) ED visits and 2 (3%) readmissions in the standard discharge group (P = 0.64 and 0.55, respectively). Patients in whom intravenous methadone was used intraoperatively were more likely to discharge POD1 (P = 0.02). There were no other significant differences in perioperative variables between the two groups including: BMI, distance from home to hospital, magnitude of main curve, curve flexibility, number of levels fused, estimated blood loss, implant density, operative time, or postoperative pain scores. Next-day discharge after PSF for AIS has an equivalent safety profile compared with longer LOS. Over one-third of patients were discharged on POD1, and there was no statistically significant difference in ED visits or hospital readmissions between the groups. Patients in whom intravenous methadone was used intraoperatively were more likely to discharge POD1. In a retrospective study of posterior spinal fusions for AIS, we found no increase in ED visits or hospital readmissions for those discharged the next day. Level III.

Efficacy of Biphasic Calcium Phosphate Ceramic With a Needle-Shaped Surface Topography Versus Autograft in Instrumented Posterolateral Spinal Fusion.

A multicenter randomized controlled noninferiority trial with intrapatient comparisons. The aim of this study was to determine noninferiority of a slowly resorbable biphasic calcium phosphate with submicron microporosity (BCP<μm, MagnetOs Granules) as an alternative for autograft in instrumented posterolateral fusion (PLF). Successful spinal fusion with a solid bone bridge between the vertebrae is traditionally achieved by grafting with autologous iliac bone. However, the disadvantages of autografts and unsatisfactory fusion rates have prompted the exploration of alternatives, including ceramics. Nevertheless, clinical evidence for the standalone use of these materials is limited. Adults indicated for instrumented PLF (1 to 6 levels) were enrolled at 5 participating centers. After bilateral instrumentation and fusion-bed preparation, the randomized allocation side (left or right) was disclosed. Per segment 10 cc of BCP<μm granules (1 to 2mm) were placed in the posterolateral gutter on one side and 10 cc autograft on the contralateral side. Fusion was systematically scored on 1-year follow-up CT scans. The study was powered to detect >15% inferiority with binomial paired comparisons of the fusion performance score per treatment side. Of the 100 patients (57 ± 12.9 y, 62% female), 91 subjects and 128 segments were analyzed. The overall posterolateral fusion rate per segment (left and/or right) was 83%. For the BCP<μm side only the fusion rate was 79% versus 47% for the autograft side (difference of 32 percentage points, 95% CI, 23-41). Analysis of the primary outcome confirmed the noninferiority of BCP<μm with an absolute difference in paired proportions of 39.6% (95% CI, 26.8-51.2; p < 0.001). This clinical trial demonstrates noninferiority and indicates superiority of MagnetOs Granules as a standalone ceramic when compared to autograft for posterolateral spinal fusion. These results challange the belief that autologous bone is the most optimal graft material.

Machine learning approach to predict venous thromboembolism among patients undergoing multi-level spinal posterior instrumented fusion.

The absence of consensus for prophylaxis of venous thromboembolism (VTE) in spine surgery underscores the importance of identifying patients at risk. This study incorporated machine learning (ML) models to assess key risk factors of VTE in patients who underwent posterior spinal instrumented fusion. Data was collected from the IBM MarketScan Database [2009-2021] for patients ≥18 years old who underwent spinal posterior instrumentation (3-6 levels), excluding traumas, malignancies, and infections. VTE incidence (deep vein thrombosis and pulmonary embolism) was recorded 90-day post-surgery. Risk factors for VTE were investigated and compared through several ML models including logistic regression, linear support vector machine (LSVM), random forest, XGBoost, and neural networks. Among the 141,697 patients who underwent spinal fusion with posterior instrumentation (3-6 levels), the overall 90-day VTE rate was 3.81%. The LSVM model demonstrated the best prediction with an area under the curve (AUC) of 0.68. The most important features for prediction of VTE included remote history of VTE, diagnosis of chronic hypercoagulability, metastatic cancer, hemiplegia, and chronic renal disease. Patients who did not have these five key risk factors had a 90-day VTE rate of 2.95%. Patients who had an increasing number of key risk factors had subsequently higher risks of postoperative VTE. The analysis of the data with different ML models identified 5 key variables that are most closely associated with VTE. Using these variables, we have developed a simple risk model with additive odds ratio ranging from 2.80 (1 risk factor) to 46.92 (4 risk factors) over 90 days after posterior spinal fusion surgery. These findings can help surgeons risk-stratify their patients for VTE risk, and potentially guide subsequent chemoprophylaxis.

Ponte osteotomies for treatment of spinal deformities: they are not all made equal.

To compare surgical outcomes of Ponte's osteotomies for treatment of adolescent idiopathic scoliosis (AIS), Scheuermann's kyphosis (SK), and adult scoliosis (AdS). We conducted a retrospective review of patients with AIS, SK, and AdIS who underwent posterior spinal instrumented fusion (PSIF) at our Institution from January 2019 to December 2022. Demographics, imaging, and intraoperative data (including number of osteotomies performed, blood losses, surgical timing, and complications) were extracted from patient charts. A total of 80 patients (62 AIS, 7 SK, and 11 AdS) were enrolled in the study. All patients were treated with a PSIF and a total of 506 Ponte osteotomies were performed (5.8 ± 4.1, 9.3 ± 2.4, and 7.5 ± 2.5 average osteotomies per patient in the AIS, SK, and AdS group, respectively; p = 0.045). Average time per osteotomy was 6.3 ± 1.5min in the AIS group, and 5.8 ± 2.1 and 8.7 ± 4.0 in the SK and AdS group, respectively (p = 0.002). Blood loss was significantly smaller in the SK group (8.6 ± 9.6ml per osteotomy) compared to AIS group (34.9 ± 23.7ml) and AdS group (34.9 ± 32.7ml) (p = 0.001). A total of 4 complications were observed in the AIS group (1.1%) and 2 complications in the AdS group (2.4%), but this was not statistically significant. Our study shows that Ponte's osteotomies are safe and effective in surgical treatment of AIS, SK, and AdS. Blood loss and execution time per osteotomy are significantly smaller in the SK group compared to AIS and AdS. No significant differences were noted in terms of complications between the three groups.

Do Hounsfield Units From Intraoperative CT Scans Correlate With Preoperative Values?

There is increasing interest in forecasting postoperative complications using bone density metrics. Vertebral Hounsfield unit measurements obtained from CT scans performed for surgical planning or other purposes, known as opportunistic CTs, have shown promise for their ease of measurement and the ability to target density measurement to a particular region of interest. Concomitant with the rising interest in prognostic bone density measurement use has been the increasing adoption of intraoperative advanced imaging techniques. Despite the interest in both outcome prognostication and intraoperative advanced imaging, there is little information regarding the use of CT-based intraoperative imaging as a means to measure bone density. (1) Can vertebral Hounsfield units be reliably measured by physician reviewers from CT scans obtained intraoperatively? (2) Do Hounsfield units measured from intraoperative studies correlate with values measured from preoperative CT scans? To be eligible for this retrospective study, patients had to have been treated with the use of an intraoperative CT scan for instrumented spinal fusion for either degenerative conditions or traumatic injuries between January 2015 and December 2022. Importantly, patients without a preoperative CT scan of the fused levels within 180 days before surgery or who were indicated for surgery because of infection, metastatic disease, or who were having revision surgery after prior instrumentation were excluded from the query. Of the 285 patients meeting these inclusion criteria, 53% (151) were initially excluded for the following reasons: 36% (102) had intraoperative CT scans obtained after placement of instrumentation, 16% (47) had undergone intraoperative CT scans but the studies were not accessible for Hounsfield unit measurement, and 0.7% (2) had prior kyphoplasty wherein the cement prevented Hounsfield unit measurement. Finally, an additional 19% (53) of patients were excluded because the preoperative CT and intraoperative CT were obtained at different peak voltages, which can influence Hounsfield unit measurement. This yielded a final population of 81 patients from whom 276 preoperative and 276 intraoperative vertebral Hounsfield unit measurements were taken. Hounsfield unit data were abstracted from the same vertebra(e) from both preoperative and intraoperative studies by two physician reviewers (one PGY3 and one PGY5 orthopaedic surgery resident, both pursuing spine surgery fellowships). For a small, representative subset of patients, measurements were taken by both reviewers. The feasibility and reliability of Hounsfield unit measurement were then assessed with interrater reliability of values measured from the same vertebra by the two different reviewers. To compare Hounsfield unit values from intraoperative CT scans with preoperative CT studies, an intraclass correlation using a two-way random effects, absolute agreement testing technique was employed. Because the data were formatted as multiple measurements from the same vertebra at different times, a repeated measures correlation was used to assess the relationship between preoperative and intraoperative Hounsfield unit values. Finally, a linear mixed model with patients handled as a random effect was used to control for different patient and clinical factors (age, BMI, use of bone density modifying agents, American Society of Anesthesiologists [ASA] classification, smoking status, and total Charlson comorbidity index [CCI] score). We found that Hounsfield units can be reliably measured from intraoperative CT scans by human raters with good concordance. Hounsfield unit measurements of 31 vertebrae from a representative sample of 10 patients, measured by both reviewers, demonstrated a correlation value of 0.82 (95% CI 0.66 to 0.91), indicating good correlation. With regard to the relationship between preoperative and intraoperative measurements of the same vertebra, repeated measures correlation testing demonstrated no correlation between preoperative and intraoperative measurements (r = 0.01 [95% CI -0.13 to 0.15]; p = 0.84). When controlling for patient and clinical factors, we continued to observe no relationship between preoperative and intraoperative Hounsfield unit measurements. As intraoperative CT and measurement of vertebral Hounsfield units both become increasingly popular, it would be a natural extension for spine surgeons to try to extract Hounsfield unit data from intraoperative CTs. However, we found that although it is feasible to measure Hounsfield data from intraoperative CT scans, the obtained values do not have any predictable relationship with values obtained from preoperative studies, and thus, these values should not be used interchangeably. With this knowledge, future studies should explore the prognostic value of intraoperative Hounsfield unit measurements as a distinct entity from preoperative measurements. Level III, diagnostic study.

Lumbar Facet Arthroplasty Versus Fusion for Grade-I Degenerative Spondylolisthesis with Stenosis: A Prospective Randomized Controlled Trial.

The comparative effectiveness of decompression plus lumbar facet arthroplasty versus decompression plus instrumented lumbar spinal fusion in patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis is unknown. In this randomized, controlled, Food and Drug Administration Investigational Device Exemption trial, we assigned patients who had single-level lumbar spinal stenosis and grade-I degenerative spondylolisthesis to undergo decompression plus lumbar facet arthroplasty (arthroplasty group) or decompression plus fusion (fusion group). The primary outcome was a predetermined composite clinical success score. Secondary outcomes included the Oswestry Disability Index (ODI), visual analog scale (VAS) back and leg pain, Zurich Claudication Questionnaire (ZCQ), Short Form (SF)-12, radiographic parameters, surgical variables, and complications. A total of 321 adult patients were randomized in a 2:1 fashion, with 219 patients assigned to undergo facet arthroplasty and 102 patients assigned to undergo fusion. Of these, 113 patients (51.6%) in the arthroplasty group and 47 (46.1%) in the fusion group who had either reached 24 months of postoperative follow-up or were deemed early clinical failures were included in the primary outcome analysis. The arthroplasty group had a higher proportion of patients who achieved composite clinical success than did the fusion group (73.5% versus 25.5%; p < 0.001), equating to a between-group difference of 47.9% (95% confidence interval, 33.0% to 62.8%). The arthroplasty group outperformed the fusion group in most patient-reported outcome measures (including the ODI, VAS back pain, and all ZCQ component scores) at 24 months postoperatively. There were no significant differences between groups in surgical variables or complications, except that the fusion group had a higher rate of developing symptomatic adjacent segment degeneration. Among patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis, lumbar facet arthroplasty was associated with a higher rate of composite clinical success than fusion was at 24 months postoperatively. Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Projections of Single-level and Multilevel Spinal Instrumentation Procedure Volume and Associated Costs for Medicare Patients to 2050.

Instrumented spinal fusions can be used in the treatment of vertebral fractures, spinal instability, and scoliosis or kyphosis. Construct-level selection has notable implications on postoperative recovery, alignment, and mobility. This study sought to project future trends in the implementation rates and associated costs of single-level versus multilevel instrumentation procedures in US Medicare patients aged older than 65 years in the United States. Data were acquired from the Centers for Medicare & Medicaid Services from January 1, 2000, to December 31, 2019. Procedure costs and counts were abstracted using Current Procedural Terminology codes to identify spinal level involvement. The Prophet machine learning algorithm was used, using a Bayesian Inference framework, to generate point forecasts for 2020 to 2050 and 95% forecast intervals (FIs). Sensitivity analyses were done by comparing projections from linear, log-linear, Poisson and negative-binomial, and autoregressive integrated moving average models. Costs were adjusted for inflation using the 2019 US Bureau of Labor Statistics' Consumer Price Index. Between 2000 and 2019, the annual spinal instrumentation volume increased by 776% (from 7,342 to 64,350 cases) for single level, by 329% (from 20,319 to 87,253 cases) for two-four levels, by 1049% (from 1,218 to 14,000 cases) for five-seven levels, and by 739% (from 193 to 1,620 cases) for eight-twelve levels (P < 0.0001). The inflation-adjusted reimbursement for single-level instrumentation procedures decreased 45.6% from $1,148.15 to $788.62 between 2000 and 2019, which is markedly lower than for other prevalent orthopaedic procedures: total shoulder arthroplasty (-23.1%), total hip arthroplasty (-39.2%), and total knee arthroplasty (-42.4%). By 2050, the number of single-level spinal instrumentation procedures performed yearly is projected to be 124,061 (95% FI, 87,027 to 142,907), with associated costs of $93,900,672 (95% FI, $80,281,788 to $108,220,932). The number of single-level instrumentation procedures is projected to double by 2050, while the number of two-four level procedures will double by 2040. These projections offer a measurable basis for resource allocation and procedural distribution.

412 Incisional Negative Pressure Wound Therapy Following Posterior Instrumented Spinal Fusion: A Single Surgeon’s Experience and Cost-Benefit Analysis

INTRODUCTION: Surgical site infections (SSIs) following spine surgery are associated with significant morbidity and resource utilization. METHODS: We retrospectively reviewed all patients who received posterior instrumented spinal fusion by the senior author between July 2017 and December 2019 at a Level I trauma center. Statistical analysis was performed using Chi-square and Student’s t-tests. RESULTS: A total of 85 patients with standard surgical dressings and 144 patients with iNPWT were included for analysis. Patients in the iNPWT group were significantly older (61.8 vs. 58.5 years, p = 0.042) and more likely to be diabetic (36.8% vs. 23.5%, p = 0.037). Surgeries in the iNPWT group were associated with significantly greater blood loss (1298 mL vs. 998 mL, p = 0.036) and involved more instrumented levels (6.6 vs. 4.9, p &lt; 0.0001). Prophylactic iNPWT use was associated with significantly lower rates of wound dehiscence (21.5% vs. 34.1%, p = 0.036) and SSI requiring operative treatment (8.3% vs. 21.2%, p = 0.005). The incidence of wound dehiscence requiring operative wound revision was lower with iNPWT (14.6% vs. 24.7%, p = 0.056), though it did not reach statistical significance. Number needed to treat (NNT) with iNPWT to prevent one SSI was 7.79. The cost of preventing one operative SSI was $5,096. Cost-benefit analysis demonstrated a potential mean savings of $26,149 per operative SSI and $326,862 per 100 patients undergoing posterior instrumented spinal fusion with iNPWT. CONCLUSIONS: Prophylactic iNPWT use significantly reduced rates of wound dehiscence, SSI requiring operative treatment, and affords a potential SSI-related cost savings of $326,862 per 100 patients treated.

Experience with the utilization of new-generation shared-control robotic system for spinal instrumentation.

Robotic assistance in spine surgery is emerging as an accurate, effective and enabling technology utilized in the treatment of patients with surgical spinal pathology. The safety and reproducibility of robotic assistance in the placement of pedicle screw instrumentation is still being investigated. The objective of this study was to present our experience of instrumented spinal fusion utilizing an intraoperative robotic guidance system. We retrospectively reviewed all cases of spinal instrumentation of the thoracic and lumbo-sacral spine using the Mazor X robotic system (Medtronic Inc, Minneapolis, MN, USA), performed at our institution by one surgeon between July 2017 and June 2020. Wilcoxon Rank test was used to compare time taken to place each screw during the first 20 cases and the cases thereafter. A total of 28 patients were included. A total of 159 screws were placed using the Mazor X robotic system. The overall mean time for screw placement was 7.8±2.3 minutes and there was a significant reduction in the mean time for screw placement after the 20th case or 120 screws (8.70 vs. 5.42 min, P=0.008). No postoperative neurologic deficit or new radiculopathy was noted to occur secondary to hardware placement. No revision surgery was required for replacement or removal of a mispositioned screw. From this single-center, single-surgeon series we conclude that robot-assisted spine surgery can be safely and efficiently integrated into the operating room workflow, which improves after a learning curve of approximately 20 operative interventions. We found robot-assisted spinal instrumentation to be reliable, safe, effective and highly precise.

Impact of a quality improvement initiative and monthly multidisciplinary meetings on outcomes after posterior spinal fusion for adolescent idiopathic scoliosis.

Several studies have demonstrated the benefits of enhanced recovery after surgery (ERAS) protocols for patients with adolescent idiopathic scoliosis (AIS) undergoing posterior spinal instrumented fusion (PSIF). However, there are relatively few studies investigating the effect of regular multidisciplinary team meetings on level selection, surgical performance parameters, and patient outcomes after PSIF for AIS. The aim of this study was to assess changes in intra- and postoperative outcomes following multidisciplinary team meeting implementation for patients undergoing PSIF for AIS. The medical records of 96 adolescents (10 to 18years old) diagnosed with AIS and undergoing PSIF at a major academic institution from 2017 to 2022 were retrospectively reviewed. A quality improvement (QI) initiative was implemented in February 2020, including institution of monthly multidisciplinary conferences focusing on preoperative indications, level selection, postoperative review of surgical performance parameters for previous cases, and discussion and optimization of postoperative ambulation and pain control protocols. Patients were placed into "Pre-QI" (treated pre-February 2020) and "Post-QI" (treated post-February 2020) cohorts. Patient demographics, comorbidities, deformity characteristics, intraoperative variables, ambulation status, postoperative complications, length of stay (LOS), and unplanned readmission rates were assessed. Of the 96 study patients, 44 (45.8%) were in the Pre-QI cohort, and 52 (54.2%) were in the Post-QI cohort. Mean major curve was not significantly different between the two cohorts (Pre-QI: 58.0 ± 7.3° vs Post-QI: 57.9 ± 14.5°, p = 0.169). The Pre-QI cohort had a greater mean minor curve degree (Pre-QI: 42.7 ± 11.8° vs Post-QI: 36.8 ± 12.4, p = 0.008). The Pre-QI cohort had significantly greater mean spinal levels fused (Pre-QI: 11.7 ± 1.7 vs Post-QI: 10.4 ± 2.6, p = 0.009), significantly greater mean estimated blood loss (Pre-QI: 1063.6 ± 631.5ml vs. Post-QI: 415.8 ± 189.9ml, p < 0.001), significantly greater mean operative time normalized to levels fused (Pre-QI: 0.6 ± 0.1h/level fused vs Post-QI: 0.4 ± 0.1h/level fused, p < 0.001), and a significantly greater proportion of patients with intraoperative drain placement (Pre-QI: 93.2% vs Post-QI: 5.8%, p < 0.001). The Post-QI cohort had significantly shorter time to postoperative ambulation (Pre-QI: 2.1 ± 0.9days vs Post-QI: 1.3 ± 0.5days, p < 0.001). A significantly greater proportion of patients in the Pre-QI cohort developed any postoperative complication (Pre-QI: 72.7% vs Post-QI: 34.6%, p < 0.001), and mean LOS was significantly greater among Pre-QI patients (Pre-QI: 4.5 ± 1.1days vs Post-QI: 3.2 ± 0.8days, p < 0.001). Discharge disposition (p = 0.758) and 30-day unplanned readmissions (p = 0.207) were similar between the cohorts. Our findings suggest that monthly multidisciplinary pediatric spine team meetings may improve patient care. Further studies exploring the incorporation of QI implementation with frequent multidisciplinary team meetings into existing ERAS protocols are merited.

A Sodium Oxychlorosene-Based Infection Prevention Protocol Safely Decreases Postoperative Wound Infections in Adult Spinal Deformity Surgery.

This study sought to determine the efficacy of a complex multi-institutional sodium oxychlorosene-based infection protocol for decreasing the rate of surgical site infection after instrumented spinal surgery for adult spinal deformity (ASD). Infection prevention protocols have not been previously studied in ASD patients. A retrospective analysis was performed of patients who underwent posterior instrumented spinal fusion of the thoracic or lumbar spine for deformity correction between January 1, 2011, and May 31, 2019. The efficacy of a multi-modal infection prevention protocol was examined. The infection prevention bundle consisted of methicillin-resistant Staphylococcus aureus testing, chlorhexidine gluconate bathing preoperatively, sodium oxychlorosene rinse, vancomycin powder placement, and surgical drain placement at the time of surgery. About 254 patients fit the inclusion criteria. Among these patients, nine (3.5%) experienced post-surgical deep-wound infection. Demographics and surgical characteristics amongst infected and non-infected cohorts were similar, although diabetes trended towards being more prevalent in patients who developed a postoperative wound infection (p=0.07). Among 222 patients (87.4%) who achieved a minimum of two years of follow-ups, 184 patients (82.9%) experienced successful fusion, comparing favorably with pseudarthrosis rates in the ASD literature. Rates of pseudarthrosis and proximal junction kyphosis were similar amongst infected and non-infected patients. An intraoperative comprehensive sodium oxychlorosene-based infection prevention protocol helped to provide a low rateof infection after major deformity correction without negatively impacting other postoperative procedure-related metrics.

Costs of revision operations for distal junctional kyphosis following thoracic posterior spinal fusion for adolescent idiopathic scoliosis

PurposeTo assess direct costs and risks associated with revision operations for distal junctional kyphosis/failure (DJK) following thoracic posterior spinal instrumented fusions (TPSF) for adolescent idiopathic scoliosis (AIS).MethodsChildren who underwent TPSF for AIS by a single surgeon (2014–2020) were reviewed. Inclusion criteria were minimum follow-up of 2 years, thoracolumbar posterior instrumented fusion with a lower instrumented vertebra (LIV) cranial to L2. Patients who developed DJK requiring revision operations were identified and compared with those who did not develop DJK.ResultsSeventy-nine children were included for analysis. Of these, 6.3% developed DJK. Average time to revision was 20.8 ± 16.2 months. Comparing index operations, children who developed DJK had significantly greater BMIs, significantly lower thoracic kyphosis postoperatively, greater post-operative lumbar Cobb angles, and significantly more LIVs cranial to the sagittal stable vertebrae (SSV), despite having statistically similar pre-operative coronal and sagittal alignment parameters and operative details compared with non-DJK patients. Revision operations for DJK, when compared with index operations, involved significantly fewer levels, longer operative times, greater blood loss, and longer hospital lengths of stay. These factors resulted in significantly greater direct costs for revision operations for DJK ($76,883 v. $46,595; p < 0.01).ConclusionsIn this single-center experience, risk factors for development of DJK were greater BMI, lower post-operative thoracic kyphosis, and LIV cranial to SSV. As revision operations for DJK were significantly more costly than index operations, all efforts should be aimed at strategies to prevent DJK in the AIS population.

Surgical management of pediatric spinal aneurysmal bone cysts: patient series.

Aneurysmal bone cysts (ABCs) are rare, highly vascular osteolytic bone lesions that predominantly affect pediatric populations. This report evaluates the clinicopathological data of pediatric patients with spinal ABCs. The medical records for all patients at Children's Hospital Los Angeles with biopsy-proven ABCs of the spine between 1998 and 2018 were evaluated. Seventeen patients, 6 males and 11 females, were identified. The mean age at surgery was 10.4 years (range, 3.5-20 years). The most common presenting complaint was pain at the lesion site 16/17 (94%), followed by lower-extremity weakness 8/17 (47%). Resection and intralesional curettage were performed in all patients. Three (18%) of 17 patients underwent selective arterial embolization prior to resection. Spinal stability was compromised in 15 of 17 patients (88%), requiring instrumented fusion. Five (29%) of the 17 patients received additional therapy including radiation, calcitonin-methylprednisolone, or phenol. Four (23.5%) of 17 patients experienced a recurrence, and the mean time to recurrence was 15 months. The postoperative follow-up ranged from 6 to 108 months (median, 28 months). Reoperation occurred after an average of 35 months. At the recent follow-up, patients were free of disease. Gross-total resection by intralesional curettage with case-dependent instrumented spinal fusion for instability remains an effective strategy for managing pediatric spinal ABCs. Long-term follow-up is necessary to detect tumor recurrence.

RESULTS OF BIPHASIC CALCIUM PHOSPHATE BONE GRAFT WITH SUBMICRON-SIZED NEEDLE-SHAPED SURFACE TOPOGRAPHY AS STANDALONE ALTERNATIVE TO AUTOGRAFT ARE FAVOURABLE IN A PROSPECTIVE, MULTICENTRE, RANDOMIZED, INTRA-PATIENT CONTROLLED TRIAL

Pseudoarthrosis after spinal fusion is an important complication leading to revision spine surgeries. Iliac Crest Bone Graft is considered the gold standard, but with limited availability and associated co-morbidities, spine surgeons often utilize alternative bone grafts.Determine the non-inferiority of a novel submicron-sized needle-shaped surface biphasic calcium phosphate (BCP&lt;µm) as compared to autograft in instrumented posterolateral spinal fusion.Adult patients indicated for instrumented posterolateral spinal fusion of one to six levels from T10-S2 were enrolled at five participating centers. After instrumentation and preparation of the bone bed, the randomized allocation side of the graft type was disclosed. One side was grafted with 10cc of autograft per level containing a minimum of 50% iliac crest bone. The other side was grafted with 10cc of BCP&lt;µm granules standalone (without autograft or bone marrow aspirate). In total, 71 levels were treated. Prospective follow-up included adverse events, Oswestry Disability Index (ODI), and a fine-cut Computerized Tomography (CT) at one year. Fusion was systematically scored as fused or not fused per level per side by two spine surgeons blinded for the procedure.The first fifty patients enrolled are included in this analysis (mean age: 57 years; 60% female and 40% male). The diagnoses included deformity (56%), structural instability (28%), and instability from decompression (20%). The fusion rate determined by CT for BCP&lt;μm was 76.1%, which compared favorably to the autograft fusion rate of 43.7%. Statistical analysis through binomial modeling showed that the odds of fusion of BCP&lt;μm was 2.54 times higher than that of autograft. 14% of patients experienced a procedure or possible device-related severe adverse event and there were four reoperations. Oswestry Disability Index (ODI) score decreased from a mean of 46.0 (±15.0) to a mean of 31.7 (±16.9), and 52.4% of patients improved with at least 15-point decrease.This data, aiming to determine non-inferiority of standalone BCP&lt;μm as compared to autograft for posterior spinal fusions, is promising. Ongoing studies to increase the power of the statistics with more patients are forthcoming.

Adolescent Perception of Stiffness After Spinal Fusion Surgery.

Posterior spinal instrumented fusion (PSIF) is a treatment option for adolescent spinal deformity. PSIF leads to loss of spinal segment motion. It is unclear the extent to which spinal stiffness is perceived by adolescent patients after fusion. Focus groups of adolescents between ages 11 and 21 years who underwent PSIF for spinal deformity were performed. Focus groups were evaluated for common themes, and a 36-question survey was designed. Survey responses were analyzed relative to last instrumented vertebra (LIV) and Scoliosis Research Society-22 (SRS-22) scores. Five focus groups were held with 18 patients in total. Three main themes were identified by participants: 56% identified difficulty bending forward, 44% identified difficulty hunching while sitting, and 56% identified difficulty with twisting motions. Patients with more distal LIV reported significant more difficulty with self-care/grooming (P = .014) and chores (P < .001). SRS-22 function/activity scores correlated well with survey categories in self-care/grooming (r = .61; P = .049) and recreation (r = .69; P = .019). Focus groups suggest that spinal stiffness is frequently perceived and leads to alteration in daily tasks in adolescents after spinal fusion.