Incidence and Risk Factors for Complications and Mortality After Vertebroplasty or Kyphoplasty in the Osteoporotic Vertebral Compression Fracture-Analysis of 1,932 Cases From the American College of Surgeons National Surgical Quality Improvement

Application of machine learning algorithms to predict 30-day hospital readmission following cement augmentation for osteoporotic vertebral compression fractures

Objective

Osteoporosis is a common skeletal disease that greatly increases the risk of pathologic fractures and accounts for approximately 700,000 vertebral compression fractures (VCFs) annually in the United States. Cement augmentation procedures such as balloon kyphoplasty (KP) and percutaneous vertebroplasty (VP) have demonstrated efficacy in the treatment of VCFs, however, some studies report rates of readmission as high as 10.8% following such procedures. The purpose of this study was to employ Machine Learning (ML) algorithms to predict 30-day hospital readmission following cement augmentation procedures for the treatment of VCFs using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database.

Methods

ACS-NSQIP was queried to identify patients undergoing either KP or VP from 2011 to 2014. Three ML algorithms were constructed and tasked with predicting post-operative readmissions within this cohort of patients. Results: Postoperative pneumonia, ASA Class 2 designation, age, partially-dependent functional status, and a history of smoking were independently identified as highly predictive of readmission by all ML algorithms. Among these variables postoperative pneumonia (p < 0.01), ASA Class 2 designation (p < 0.01), age (p = 0.002), and partially-dependent functional status (p < 0.01) were found to be statistically significant. Predictions were generated with an average AUC value of 0.757 and an average accuracy of 80.5%.

Conclusions

Postoperative pneumonia, ASA Class 2 designation, partially-dependent functional status, and age are perioperative variables associated with 30-day readmission following cement augmentation procedures. The use of ML allows for quantification of the relative contributions of these variables toward producing readmission.

Spinal infection after vertebral augmentation: a covert complication with serious havoc

INTRODUCTION

Vertebral augmentation, including percutaneous vertebroplasty (PVP) or kyphoplasty (PKP), is the current least invasive surgical option and has been widely used to treat the painful osteoporotic vertebral compression fractures (OVCF). However, the postoperative infections could be life-threatening, even though they rarely occur. Our studies aim to clarify the causation and outcomes of spinal infections following augmentation and meanwhile to identify the risk factors.

METHODS

A retrospective study was conducted on patients with OVCF who underwent PVP or PKP, and were subsequently admitted to our institution with postoperative spinal infection between January 2010 and December 2022. A total of 33 patients were finally included.

RESULTS

The rate of spinal infection after augmentation in our single institute was 0.05% (2/3893). In addition to these 2 patients, the remaining 31 were referred from other hospitals. All 33 patients exhibited elevated inflammatory parameters, 14 patients presented with fever, and 9 patients experienced neurological deficits. Additionally, 29 patients had comorbidity and risk factors. Pathogens were identified in 26 patients, while only 7 patients were examined as culture negative. 27 patients underwent revision surgery and 6 patients only received conservative therapy. Anterior surgery was performed in 2 patients, while posterior surgery was performed in 20 patients. A combined anterior-posterior surgery was performed in 5 patients. At the final follow-up, 18 patients had unrestricted mobility, 10 patients required assistance from crutches or a walker for ambulation, 4 patients needed a wheelchair, and 1 patients died after revision surgery.

CONCLUSIONS

Spinal infection after vertebral augmentation is rare, but it cannot be ignored. Surgeons should make every effort to detect the potential preoperative spondylitis or discitis. Once postoperative spinal infection is confirmed, a prompt intravenous antibiotic therapy is warranted. If medication therapy fails, revision surgery involving debridement and spinal reconstruction should be considered.

In-hospital mortality trends after surgery for traumatic thoracolumbar injury: A national inpatient sample database study

Introduction

Given the increasing incidence of traumatic thoracolumbar injuries in recent years, studies have sought to investigate potential risk factors for outcomes in these patients.

Research question

The aim of this study was to investigate trends and risk factors for in-hospital mortality after fusion for traumatic thoracolumbar injury.

Materials and methods

Patients undergoing thoracolumbar fusion after traumatic injury were queried from the National Inpatient Sample (NIS) from 2012 to 2017. Analysis was performed to identify risk factors for inpatient mortality after surgery.

Results

Patients in 2017 were on average older (51.0 vs. 48.5, P = 0.004), had more admitting diagnoses (15.5 vs. 10.7, p < 0.001), were less likely to be White (75.8% vs. 81.2%, p = 0.006), were from a ZIP code with a higher median income quartile (Quartile 1: 31.4% vs. 28.6%, p = 0.011), and were more likely to have Medicare as a primary payer (22.9% vs. 30.1%, p < 0.001). Bivariate analysis of demographics and surgical characteristics demonstrated that patients in the in-hospital mortality group (n = 90) were older (70.2 vs. 49.6, p < 0.001), more likely to be male (74.4% vs. 62.8%, p = 0.031), had a great number of admitted diagnoses (21.3 vs. 12.7, p < 0.001), and were more likely to be insured by Medicare (70.0% vs. 27.0%, p < 0.001). Multivariate regression analysis found age (OR 1.06, p < 0.001) and Black race (OR 3.71, p = 0.007) were independently associated with in-hospital mortality.

Conclusion

Our study of nationwide, traumatic thoracolumbar fusion procedures from 2012 to 2017 in the NIS database found older, black patients were at increased risk for in-hospital mortality after surgery.

Analysis of Prognostic Factors in Osteoporotic Patients Who Were Treated with Percutaneous Vertebroplasty for Refracture After Vertebral Augmentation

OBJECTIVE

To retrospectively analyze prognostic factors in osteoporotic patients who treated with percutaneous vertebroplasty for refracture after vertebral augmentation.

METHODS

A retrospective analysis was performed of 61 patients with refractures after vertebral augmentation who received percutaneous vertebroplasty treatment again from January 2019 to December 2021. Based on the presence of back pain at the last follow-up, 17 patients were placed in the pain group, and 44 patients were placed in the pain-free group. The following covariates were reviewed: age; bone mineral density; bone cement dosage; bone cement leakage; body mass index; and rate of anterior vertebral height (AVH) loss in the target before surgery, 1 week after surgery, and at last follow-up. Patients were assessed using visual analogue scale score and Oswestry Disability Index.

RESULTS

Binary logistic regression analysis revealed that the rate of AVH loss after surgery was associated with postoperative back pain. According to the receiver operating characteristic curve analysis, the area under the curve of AVH loss rate at 1 week after surgery was 0.6845, and the cutoff value was 0.18; the area under the curve of AVH loss rate at the last follow-up was 0.7306, and the cutoff value was 0.2815. Kaplan-Meier survival analysis showed that patients with lower AVH loss rates had lower incidence of postoperative back pain and better prognosis.

CONCLUSIONS

Occurrence of postoperative back pain was strongly associated with AVH loss after surgery. Patients with a lower rate of AVH loss had a lower incidence of postoperative back pain and a better prognosis.

A Novel PTH-Related Peptide Combined With 3D Printed Macroporous Titanium Alloy Scaffold Enhances Osteoporotic Osseointegration

Previous parathyroid hormone (PTH)-related peptides (PTHrPs) cannot be used to prevent implant loosening in osteoporosis patients due to the catabolic effect of local sustained release. A novel PTHrP (PTHrP-2) that can be used locally to promote osseointegration of macroporous titanium alloy scaffold (mTAS) and counteract implant slippage in osteoporosis patients is designed. In vitro, PTHrP-2 enhances the proliferation, adhesion, and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) within the mTAS. Further, it promotes proliferation, migration, angiogenesis-related protein expression, and angiogenesis in human umbilical vein endothelial cells (HUVECs). Compared to PTH(1-34), PTHrP-2 can partially weaken the osteoclast differentiation of RAW 264.7 cells. Even in an oxidative stress microenvironment, PTHrP-2 safeguards the proliferation and migration of BMSCs and HUVECs, reduces reactive oxygen species generation and mitochondrial damage, and partially preserves the angiogenesis of HUVECs. In the Sprague-Dawley (SD) rat osteoporosis model, the therapeutic benefits of PTHrP-2-releasing mTAS (mTASP2 ) and ordinary mTAS implanted for 12 weeks via micro-CT, sequential fluorescent labeling, and histology are compared. The results demonstrate that mTASP2 exhibits high bone growth rate, without osteophyte formation. Consequently, PTHrP-2 exhibits unique local synthesis properties and holds the potential for assisting the osseointegration of alloy implants in osteoporosis patients.

Risk of Revision After Vertebral Augmentation for Osteoporotic Vertebral Fracture: A Narrative Review

Osteoporotic vertebral fractures (OVFs) can hinder physical motor function, daily activities, and the quality of life in elderly patients when treated conservatively. Vertebral augmentation, which includes vertebroplasty and balloon kyphoplasty, is a commonly used procedure for OVFs. However, there have been reports of complications. Although serious complications are rare, there have been instances of adjacent vertebral fractures, cement dislocation, and insufficient pain relief due to cement failure, sometimes necessitating revision surgery. This narrative review discusses the common risks associated with vertebral augmentation for OVFs, such as cement leakage and adjacent vertebral fractures, and highlights the risk of revision surgery. The pooled incidence of revision surgery was 0.04 (0.02-0.06). The risks for revision are reported as follows: female sex, advanced age, diabetes mellitus, cerebrovascular disease, dementia, blindness or low vision, hypertension, hyperlipidemia, split type fracture, large angular motion, and large endplate deficit. Various treatment strategies exist for OVFs, but they remain a subject of controversy. Current literature underscores the lack of substantial evidence to guide treatment strategies based on the risks of vertebral augmentation. In cases with a high risk of failure, other surgeries and conservative treatments should also be considered as treatment options.

Unsubtracted Roadmap Technique for Preventing Cement Leakage During Percutaneous Vertebroplasty: A Retrospective Cohort Study

OBJECTIVE

To determine the effectiveness of the unsubtracted roadmap technique (USRT) for decreasing cement leakage (CL) during percutaneous vertebroplasty (PVP).

METHODS

In this retrospective cohort study, patients who underwent PVP between January and November 2018 were included. Patients were divided into the unsubtracted roadmap (UR) (n = 20) and conventional venography (CV) (n = 22) groups. USRT was performed before cement injection in the UR group. Computed tomography was performed on the first day after PVP in both groups to assess the CL. The vertebral height restoration rate was confirmed by radiography before and after the procedure. The CL location was classified as basivertebral vein (type B), segmental vein (type S), or cortical defect (type C). Visual analog scale and Oswestry Disability Index scores before and after surgery were calculated to confirm clinical outcomes.

RESULTS

Based on the computed tomography images, CL occurred in 7 (34.78%) and 15 (63.64%) cases in the UR and CV groups, respectively. Number of CL type B, S, and C in the UR and CV groups were 2 and 6, 3 and 6, and 2 and 3, respectively. The injected cement volume was not significantly different between the UR (4.86 mL) and the CV (4.75 mL) groups (P = 0.450). Regarding vertebral body height restoration (P = 0.856) and clinical outcomes, there were no significant differences between both groups. Radiation exposure was significantly less in the UR group (P = 0.019).

CONCLUSIONS

USRT is an effective method for reducing CL and radiation exposure during PVP.

Investigation of preoperative asymptomatic bacteriuria as a risk factor for postvertebroplasty infection

BACKGROUND

Postvertebroplasty infection (PVI) is a catastrophic complication after vertebroplasty (VP). Although the urinary tract has been considered as a source of infectious pathogens, whether asymptomatic bacteriuria (ASB) is a risk factors for PVI remains unknown.

METHODS

This retrospective study included 716 patients (207 males; 509 females) treated with VP for osteoporotic vertebral fractures in a single medical center between May 2015 and December 2019. Clinical symptoms, urinalysis results, and culture data were collected preoperatively to identify patients with ASB. The primary outcome was PVI at the index level during follow-up. Demographic data and laboratory test results were compared between the PVI and non-PVI groups.

RESULTS

The mean age of the cohort was 78.6 ± 9.6 (range, 63-106). The prevalence of ASB was 14.1%, with female predominance (63.4%). The overall PVI rate was 1.26% (9/716). The PVI group had more patients with ASB (4/9, 44.4%) than did the non-PVI group (97/707, 13.7%) (p = 0.027). The rate of ASB treatment was similar between the PVI and non-PVI groups (25% vs. 23.7%, respectively). No case of PVI was caused by the urine culture pathogen. Multivariate analysis identified the following risk factors for PVI: ASB (odds ratio [OR], 5.61; 95% CI, 1.14-27.66; p = 0.034), smoking (OR, 16.26; 95% CI, 2.58-102.65; p = 0.003), and malignancy (OR 7.27; 95% CI, 1.31-40.31; p = 0.023).

CONCLUSION

ASB was not uncommon among patients admitted for VP and should be considered a marker of relatively poor host immunity. Preoperative ASB, a history of malignancy, and smoking were identified as significant risk factors for PVI.

Novel Polyethylene Terephthalate Screw Sleeve Implant: Salvage Treatment in a Case of Spine Instability after Vertebroplasty Failure

INTRODUCTION

The management of osteoporotic fractures is sometimes rather challenging for spinal surgeons, and considering the longer life expectancy induced by improved living conditions, their prevalence is expected to increase. At present, the approaches to osteoporotic fractures differ depending on their severity, location, and the patient's age. State-of-the-art treatments range from vertebroplasty/kyphoplasty to hardware-based spinal stabilization in which screw augmentation with cement is the gold standard.

CASE PRESENTATION

We describe the case of a 74-year-old man with an L5 osteoporotic fracture. The patient underwent a vertebroplasty (VP) procedure, which was complicated by a symptomatic cement leakage in the right L4-L5 neuroforamen. We urgently decompressed the affected pedicle via hemilaminectomy. At that point, the column required stability. The extravasation of cement had ruled out the use of cement-augmented pedicle screws but leaving the pedicular screws alone was not considered sufficient to achieve stability. We decided to cover the screws with a polyethylene terephthalate sleeve (OGmend^®) to avoid additional cement leakage and to reinforce the screw strength required by the poor bone quality.

CONCLUSION

In the evolving technologies used for spinal surgery, screws sleeve implants such as OGmend^® are a useful addition to the surgeon's armamentarium when an increased pull-out strength is required and other options are not available.

Association of Body Mass Index with Long-Term All-Cause Mortality in Patients Who Had Undergone a Vertebroplasty for a Vertebral Compression Fracture

We aimed to investigate the association between preoperative body mass index (BMI) and postoperative long-term mortality in patients who underwent a vertebroplasty. We retrospectively enrolled patients with a vertebral compression fracture who underwent a vertebroplasty between May 2013 and June 2020 in a medical center in Taiwan. The survival status of the study sample was confirmed by the end of March 2021. Cox-proportional hazard models were conducted to examine the effects of being overweight/obese (≥25 kg/m2 vs. <25 kg/m2) and BMI (as a continuous variable) on all-cause mortality after adjusting for age, sex, history of smoking, diabetes, hypertension, chronic kidney disease, and osteoporosis. A total of 164 patients were analyzed (mean age 75.8 ± 9.3 years, male 25.6%, mean BMI 24.0 ± 4.1 kg/m2) after a median follow-up of 785 days. Compared with a BMI < 25 kg/m2, a BMI ≥ 25 kg/m2 was associated with a significantly lower risk of all-cause mortality (HR 0.297, 95% CI 0.101 to 0.878, p = 0.028). These findings were consistent when BMI was examined as a continuous variable (HR 0.874, 95% CI 0.773 to 0.988, p = 0.031). A low BMI (<22 kg/m2) should be considered as a risk factor for postoperative long-term mortality in this ageing population.

[Cement augmentation in spinal surgery]

Bone cement has been used in spinal surgery for as long as 50 years. In contemporary spinal surgery, cement augmentation of fractured osteoporotic vertebrae in the form of vertebroplasty/kyphoplasty as well as cement augmentation of pedicle screws in instrumented procedures of any etiology are established as standard procedures. Both procedures are very effective, although the benefits of vertebroplasty/kyphoplasty procedures have been controversially discussed in the past. Overall, complications rarely occur. The most relevant complication is cement leakage, which is asymptomatic in the majority of cases but in the worst case might lead to neurological deficits, embolic events and even circulatory collapse. Prevention of cement leakage is therefore crucial. Risk factors for cement leakage and preventive measures are presented in a comprehensive review based on the available literature.

Development and validation of a nomogram for predicting the probability of new vertebral compression fractures after vertebral augmentation of osteoporotic vertebral compression fractures

INTRODUCTION

New vertebral compression fractures (NVCFs) are adverse events after vertebral augmentation of osteoporotic vertebral compression fractures (OVCFs). Predicting the risk of vertebral compression fractures (VCFs) accurately after surgery is still a significant challenge for spinal surgeons. The aim of our study was to identify risk factors of NCVFs after vertebral augmentation of OVCFs and develop a nomogram.

METHODS

We retrospectively reviewed the medical records of patients with OVCFs who underwent percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP). Patients were divided into the NVCFs group and control group, base on the patients with or without NVCFs within 2 years follow-up period after surgery. A training cohort of 403 patients diagnosed in our hospital from June 2014 to December 2016 was used for model development. The independent predictive factors of postoperative VCFs were determined by least absolute shrinkage and selection operator (LASSO) logistic regression, univariate analysis and multivariate logistic regression analysis. We provided a nomogram for predicting the risk of NVCFs based on independent predictive factors and used the receiver operating characteristic curve (ROC), calibration curve, and decision curve analyses (DCA) to evaluated the prognostic performance. After internal validation, the nomogram was further evaluated in a validation cohort of 159 patients included between January 2017 and June 2018.

RESULTS

Of the 403 patients in the training cohort, 49(12.16%) were NVCFs at an average of 16.7 (1 to 23) months within the 2 years follow-up period. Of the 159 patients in the validation cohort, 17(10.69%) were NVCFs at an average of 8.7 (1 to 15) months within the 2 years follow-up period. In the training cohort, the proportions of elderly patients older than 80 years were 32.65 and 13.56% in the NVCFs and control group, respectively (p = 0.003). The percentages of patients with previous fracture history were 26.53 and 12.71% in the NVCFs and control group, respectively (p = 0.010). The volume of bone cement were 4.43 ± 0.88 mL and 4.02 ± 1.13 mL in the NVCFs and Control group, respectively (p = 0.014). The differences have statistical significance in the bone cement leakage, bone cement dispersion, contact with endplate, anti-osteoporotic treatment, post-op Cobb angle and Cobb angle restoration characteristics between the two groups. The model was established by multivariate logistic regression analysis to obtain independent predictors. In the training and validation cohort, the AUC of the nomogram were 0.882 (95% confidence interval (CI), 0.824-0.940) and 0.869 (95% CI: 0.811-0.927), respectively. The C index of the nomogram was 0.886 in the training cohort and 0.893 in the validation cohort, demonstrating good discrimination. In the training and validation cohort, the optimal calibration curves demonstrated the coincidence between prediction and actual status, and the decision curve analysis demonstrated that the full model had the highest clinical net benefit across the entire range of threshold probabilities.

CONCLUSION

A nomogram for predicting NVCFs after vertebral augmentation was established and validated. For patients evaluated by this model with predictive high risk of developing postoperative VCFs, postoperative management strategies such as enhance osteoporosis-related health education and management should be considered.