Risk factors of early complications after thoracic and lumbar spinal deformity surgery: a systematic review and meta-analysis

The influence of osteoporosis on mechanical complications in lumbar fusion surgery: a systematic review

Background

Adults undergoing spine surgery often have underlying osteoporosis, which may be a risk factor for postoperative complications. Although these associations have been described, osteoporosis remains profoundly underdiagnosed and undertreated in the spine surgery population. A thorough, comprehensive systematic review summarizing the relationships between bone mineral density (BMD) and specific complications of lumbar fusion surgery could be a valuable resource for raising awareness and supporting clinical practice changes.

Methods

PubMed, Embase, and Web of Science databases were searched for original clinical research articles reporting on BMD, or surrogate measure, as a predictor of complications in adults undergoing elective lumbar fusion for degenerative disease or deformity. Endpoints included cage subsidence, screw loosening, pseudarthrosis, vertebral fracture, junctional complications, and reoperation.

Results

A total of 71 studies comprising 12,278 patients were included. Overall, considerable heterogeneity in study populations, methods of bone health assessment, and definition and evaluation of clinical endpoints precluded meta-analysis. Nevertheless, low BMD was associated with higher rates of implant failures like cage subsidence and screw loosening, which were often diagnosed with concomitant pseudarthrosis. Osteoporosis was also a significant risk factor for proximal junctional kyphosis, particularly due to fracture. Many studies found surgical site-specific BMD to best predict focal complications. Functional outcomes were inconsistently addressed.

Conclusions

Our findings suggest osteoporosis is a significant risk factor for mechanical complications of lumbar fusion. These results emphasize the importance of preoperative osteoporosis screening, which allows for medical and surgical optimization of high-risk patients. This review also highlights current practical challenges facing bone health evaluation in patients undergoing elective surgery. Future prospective studies using standardized methods are necessary to strengthen existing evidence, identify optimal predictive thresholds, and establish specialty-specific practice guidelines. In the meantime, an awareness of the surgical implications of osteoporosis and utility of preoperative screening can provide for more informed, effective patient care.

Safety and Efficacy of Tranexamic Acid in Spinal Surgery: A Systematic Review and Meta-Analysis

Background

Tranexamic acid (TXA) has gained popularity in spinal surgery because of its potential to reduce blood loss. However, concerns regarding its safety and efficacy remain. This systematic review and meta-analysis aimed to evaluate the efficacy of TXA in reducing blood loss and its safety profile in spinal surgeries.

Methods

A comprehensive search was conducted in electronic databases for randomized controlled trials and prospective studies evaluating the use of TXA in spinal surgery. The primary outcomes were intraoperative and total estimated blood loss (EBL), and the secondary outcomes included the incidence and types of complications associated with TXA use. Meta-analyses were performed using random-effects models.

Results

Thirteen studies involving 1,213 participants were included in the meta-analysis. The use of TXA was associated with significant reductions in both intraoperative (mean difference: -46.56 mL [-73.85, -19.26], p<0.01]) and total EBL (mean difference: -210.17 mL [-284.93, -135.40], p<0.01) while also decreasing the need for blood transfusions (risk ratio: 0.68 [0.51, 0.90], p<0.01). No significant difference was found in the incidence and types of thrombotic complications when TXA was used in spinal surgery. Subgroup analysis showed consistent results in instrumentation and fusion surgery and different doses of TXA.

Conclusions

TXA is effective in reducing intraoperative and overall blood loss in spinal surgery without increasing the risk of complications. These findings support the use of TXA to improve patient outcomes. However, caution should be exercised because of the heterogeneity among the included studies. Further research is needed to confirm these findings and explore potential long-term complications.

Predicting Complications in 153 Lumbar Pedicle Subtraction Osteotomies by a Single Surgeon Over a 6-Year Period

INTRODUCTION

Pedicle subtraction osteotomy (PSO) is a complex surgical procedure that provides correction of moderate sagittal imbalance. Surgical complications have adverse effects on patient outcomes and healthcare costs, making it imperative for clinical researchers to focus on minimizing complications. However, when it comes to risk modeling of PSO surgery, there is currently no consensus on which patient characteristics or measures should be used. This study aimed to describe complications and compare the performance of various sociodemographic characteristics, surgical variables, and established risk indices in predicting postoperative complications, infections, and readmissions after lumbar PSO surgeries.

METHODS

A review was conducted on 191 patients who underwent PSO surgery at a single institution by a single fellowship-trained orthopaedic spine surgeon between January 1, 2018, and December 31, 2021. Demographic, intraoperative, and postoperative data within 30 days, 1 year, and 2 years of the index procedure were evaluated. Descriptive statistics, t-test, chi-squared analysis, and logistic regression models were used.

RESULTS

Intraoperative complications were significantly associated with coronary artery disease (odds ratios [OR] 3.95, P = 0.03) and operating room time (OR 1.01, P = 0.006). 30-day complications were significantly cardiovascular disease (OR 2.68, P = 0.04) and levels fused (OR 1.10, P = 0.04). 2-year complications were significantly associated with cardiovascular disease (OR 2.85, P = 0.02). 30-day readmissions were significantly associated with sex (4.47, 0.04) and length of hospital stay (χ2 = 0.07, P = 0.04). 2-year readmissions were significantly associated with age (χ2 = 0.50, P = 0.03), hypertension (χ2 = 4.64, P = 0.03), revision surgeries (χ2 = 5.46, P = 0.02), and length of hospital stay (χ2 = 0.07, P = 0.03).

DISCUSSION

This study found that patients with coronary vascular disease and longer fusions were at higher risk of postoperative complications and patients with notable intraoperative blood loss were at higher risk of postoperative infections. In addition, physicians should closely follow patients with extended postoperative hospital stays, with advanced age, and undergoing revision surgery because these patients were more likely to be readmitted to the hospital.

Perioperative Nutritional, Functional, and Bone Health Optimization in Spine Surgery: A National Investigation of Spine Surgeons' Perceptions and Practices

INTRODUCTION

While perioperative nutritional, functional, and bone health status optimization in spine surgery is supported with ample evidence, the implementation and surgeon perception regarding such efforts in clinical practice remain largely unexplored. This study sought to assess the current perception of spine surgeons and implementation regarding the nutritional, functional status, and bone health perioperative optimization.

METHODS

An anonymous 30-question survey was distributed to orthopaedic spine fellowship and neurosurgery program directors identified through the North American Spine Society and American Association of Neurological Surgeons contact databases.

RESULTS

The questionnaire was completed by 51 surgeon survey respondents. Among those, 62% reported no current formal nutritional optimization protocols with 14% not recommending an optimization plan, despite only 10% doubting benefits of nutritional optimization. While 5% of respondents perceived functional status optimization as nonbeneficial, 68% of respondents reported no protocol in place and 46% noted a functional status assessment relying on patient dependency. Among the respondents, 85% routinely ordered DEXA scan if there was suspicion of osteoporosis and 85% usually rescheduled surgery if bone health optimization goals were not achieved while 6% reported being suspicious of benefit from such interventions.

CONCLUSION

While most responding spine surgeons believe in the benefit of perioperative nutritional and functional optimization, logistical and patient compliance challenges were noted as critical barriers toward optimization. Understanding surgeon perception and current practices may guide future efforts toward advancement of optimization protocols.

Development and external validation of a nomogram for predicting postoperative adverse events in elderly patients undergoing lumbar fusion surgery: comparison of three predictive models

BACKGROUND

The burden of lumbar degenerative diseases (LDD) has increased substantially with the unprecedented aging population. Identifying elderly patients with high risk of postoperative adverse events (AEs) and establishing individualized perioperative management is critical to mitigate added costs and optimize cost-effectiveness to the healthcare system. We aimed to develop a predictive tool for AEs in elderly patients with transforaminal lumbar interbody fusion (TLIF), utilizing multivariate logistic regression, single classification and regression tree (hereafter, "classification tree"), and random forest machine learning algorithms.

METHODS

This study was a retrospective review of a prospective Geriatric Lumbar Disease Database (age ≥ 65). Our outcome measure was postoperative AEs, including prolonged hospital stays, postoperative complications, readmission, and reoperation within 90 days. Patients were grouped as either having at least one adverse event (AEs group) or not (No-AEs group). Three models for predicting postoperative AEs were developed using training dataset and internal validation using testing dataset. Finally, online tool was developed to assess its validity in the clinical setting (external validation).

RESULTS

The development set included 1025 patients (mean [SD] age, 72.8 [5.6] years; 632 [61.7%] female), and the external validation set included 175 patients (73.2 [5.9] years; 97 [55.4%] female). The predictive ability of our three models was comparable, with no significant differences in AUC (0.73 vs. 0.72 vs. 0.70, respectively). The logistic regression model had a higher net benefit for clinical intervention than the other models. A nomogram based on logistic regression was developed, and the C-index of external validation for AEs was 0.69 (95% CI 0.65-0.76).

CONCLUSION

The predictive ability of our three models was comparable. Logistic regression model had a higher net benefit for clinical intervention than the other models. Our nomogram and online tool ( https://xuanwumodel.shinyapps.io/Model_for_AEs/ ) could inform physicians about elderly patients with a high risk of AEs within the 90 days after TLIF surgery.

Inducing Angiogenesis in the Nucleus Pulposus

Bone morphogenetic protein (BMP) gene delivery to Lewis rat lumbar intervertebral discs (IVDs) drives bone formation anterior and external to the IVD, suggesting the IVD is inhospitable to osteogenesis. This study was designed to determine if IVD destruction with a proteoglycanase, and/or generating an IVD blood supply by gene delivery of an angiogenic growth factor, could render the IVD permissive to intra-discal BMP-driven osteogenesis and fusion. Surgical intra-discal delivery of naïve or gene-programmed cells (BMP2/BMP7 co-expressing or VEGF165 expressing) +/- purified chondroitinase-ABC (chABC) in all permutations was performed between lumbar 4/5 and L5/6 vertebrae, and radiographic, histology, and biomechanics endpoints were collected. Follow-up anti-sFlt Western blotting was performed. BMP and VEGF/BMP treatments had the highest stiffness, bone production and fusion. Bone was induced anterior to the IVD, and was not intra-discal from any treatment. chABC impaired BMP-driven osteogenesis, decreased histological staining for IVD proteoglycans, and made the IVD permissive to angiogenesis. A soluble fragment of VEGF Receptor-1 (sFlt) was liberated from the IVD matrix by incubation with chABC, suggesting dysregulation of the sFlt matrix attachment is a possible mechanism for the chABC-mediated IVD angiogenesis we observed. Based on these results, the IVD can be manipulated to foster vascular invasion, and by extension, possibly osteogenesis.