Safety and efficacy of cement augmentation with fenestrated pedicle screws for tumor-related spinal instability

Modalities of failure of cement-augmented pedicle screws

INTRODUCTION

Cement-augmented pedicle screw instrumentation procedures are performed for stabilization in patients with surgical spinal conditions with poor bone quality at the target levels. Although this is done to combat the risk of failure due to loosening, cutting out or pulling out of the screws, failure may still occur. The purpose of this study was to identify the modalities and rates of failure of CAPSI constructs to better predict occurrence of failure.

METHODS

We retrospectively reviewed clinical data of patients who underwent CAPSI fusion procedures between 2010 and 2022. We collected pre, intra and post-operative clinical and radiographic data.

RESULTS

621 pedicle screws in 319 levels were augmented out of 1333 screws in 809 instrumented levels in 120 patients. F:M = 3:1; mean age 68.6 years and mean BMI 27.10. The mean length of follow up overall was 2.2 years (Range 7 days-11 years). The most common surgical indications were degenerative scoliosis and osteoporotic fractures. Construct failure occurred in 32 cases; seven cases were associated with trauma and 11 cases presented with a neurologic deficit. The most common modality of failure was osteonecrotic collapse (20 cases); proximal construct failure occurred in 22 cases; there was evidence of haloing at the screw-bone-cement interfaces in 23 out 32 cases. 21 out of 32 cases required revision surgical procedures within an average of 453 days.

CONCLUSION

Failure of CAPSI constructs occurred in 26.7% of patients. High occurrence of osteonecrotic collapse and haloing at the screw-cement-bone interfaces likely represents a relationship with construct failure.

Comparative analysis of the safety and efficacy of fenestrated pedicle screw with cement and conventional pedicle screw with cement in the treatment of osteoporotic vertebral fractures: A meta-analysis

PURPOSE

Bone cement-reinforced fenestrated pedicle screws (FPSs) have been widely used in the internal fixation and repair of the spine with osteoporosis in recent years and show significant improvement in fixation strength and stability. However, compared with conventional reinforcement methods, the advantages of bone cement-reinforced FPSs remain undetermined. This article compares the effects of fenestrated and conventional pedicle screws (CPSs) combined with bone cement in the treatment of osteoporosis.

METHODS

A clinical control study of FPSs and CPSs combined with bone cement reinforcement in osteoporotic vertebral internal fixation was performed using the database PubMed, Embase, Cochrane Library, CNKI, the Wanfang, and the China Biomedical Literature Service System. Two evaluators screened the relevant literature in strict accordance with the inclusion criteria (diagnosis of participants, type of clinical study, treatment with FPS and CPS, and outcome indicators) and exclusion criteria (duplicate literature and missing or incorrect data) and independently conducted data extraction and quality evaluation. Clinical control studies of direct comparison between FPS and CPS combined with bone cement reinforcement in patients who were definitively diagnosed with thoracolumbar fractures or spinal degenerative diseases were included. Quality evaluation was conducted using the Cochrane risk bias evaluation tool for randomized controlled studies and using the Newcastle-Ottawa scale for retrospective case-control studies. RevMan software (version 5.3) was used for the meta-analysis to compare the clinical efficacy, radiological results, and related complications of the 2 methods.

RESULTS

A total of 13 articles were included, including 7 randomized controlled studies and 6 retrospective case-control studies. There were 909 patients in these studies, 451 in the FPS and polymethyl methacrylate (FPS & PMMA) group and 458 in the CPS and polymethyl methacrylate (CPS & PMMA) group. The results of the meta-analysis showed that there was no significant difference between the 2 groups in operation time, hospital stay, visual analogue score, Japanese orthopaedic association score, Oswestry disability index score, Cobb angle, vertebral body deformation index and fusion rate (p > 0.05). The mean difference of intraoperative bleeding volume was -10.45, (95% confidence intervals (CI) (-16.92, -3.98), p = 0.002), the mean difference of loss height of the anterior edge of the vertebral body after surgery was -0.69 (95% CI (-0.93, -0.44), p < 0.001), and the relative risk (RR) of overall complication rate was 0.43 (95% CI (0.27, 0.68), p < 0.001), including the RR of bone cement leakage rate was 0.57 (95% CI (0.39, 0.85), p = 0.005). The screw loosening rate (RR = 0.26, 95% CI (0.13, 0.54), p < 0.001) of the FPS group was significantly lower than that of the CPS group.

CONCLUSION

The existing clinical evidence shows that compared with the CPS combined with bone cement, the use of FPS repair in the internal fixation of an osteoporotic vertebral body can reduce the amount of intraoperative bleeding, be more conducive to maintaining the height of the vertebral body, and significantly reduce the incidence of postoperative complications such as bone cement leakage and screw loosening.

The Correlation Analysis Between the Pedicle Screw Placement Palpation and Torque

BACKGROUND

This study endeavored to investigate the influencing factors of pedicle screw torque measured during surgery and the correlation between manual palpation scores and screw torque.

METHODS

This investigation was a prospective study designed to gather data from patients who underwent spinal internal fixation performed by the same surgical team at the Department of Orthopedics, affiliated with the First Hospital of Guangzhou University of Chinese Medicine, spanning from January 2020 to September 2023. The sample comprised 51 individuals (18 males and 33 females; mean age: 60.78±11.48 years). All participants underwent bone mineral density (BMD) and comprehensive radiological testing to evaluate the affected spinal segments. Intraoperatively, parameters such as the surgeon's tactile perception, a visual analog scale for manual palpation, and peak screw torque values were documented. Patients were subsequently stratified into 3 categories based on the resistance encountered during screw placement. Demographic variables (age, height, and weight) and BMD measurements of patients within each category were compared. Factors exhibiting significant differences were subjected to multivariate logistic regression analysis. Concurrently, the relationship between manual palpation scores and torque values was examined.

RESULTS

The results of the univariate analysis indicated that age (P = 0.042), height (P = 0.047), BMD of the lumbar (P < 0.01), BMD of the femoral neck (P = 0.02), BMD of the hip (P = 0.02), and P1NP (P = 0.044) were statistically significant. The results of multivariate logistic regression analysis revealed that BMD of the lumbar was an independent influencing factor for torque (P=0.000<0.05). Additionally, the manual palpation score and torque value of group A were significantly lower than those of the other 2 groups (P < 0.001). There was a significant positive correlation between the intraoperative screw placement palpation and torque.

CONCLUSIONS

The BMD of the lumbar is an independent factor that influences the measured torque applied to pedicle screws during surgery. A significant and robust positive correlation exists between the intraoperative screw placement tactile sensation and the torque experienced. It is advisable to reinforce the screw channel with bone cement when the tactile score is ≤2.5 and the torque is ≤ 1.3 Nm.

A Multidisciplinary Update on Treatment Modalities for Metastatic Spinal Tumors with a Surgical Emphasis: A Literature Review and Evaluation of the Role of Artificial Intelligence

Spinal metastases occur in up to 40% of patients with cancer. Of these cases, 10% become symptomatic. The reported incidence of spinal metastases has increased in recent years due to innovations in imaging modalities and oncological treatments. As the incidence of spinal metastases rises, so does the demand for improved treatments and treatment algorithms, which now emphasize greater multidisciplinary collaboration and are increasingly customized per patient. Uniquely, we discuss the potential clinical applications of AI and NGS in the treatment of spinal metastases. Material and Methods: A PubMed search for articles published from 2000 to 2023 regarding spinal metastases and artificial intelligence in healthcare was completed. After screening for relevance, the key findings from each study were summarized in this update. Results: This review summarizes the evidence from studies reporting on treatment modalities for spinal metastases, including minimally invasive surgery (MIS), external beam radiation therapy (EBRT), stereotactic radiosurgery (SRS), CFR-PEEK instrumentation, radiofrequency ablation (RFA), next-generation sequencing (NGS), artificial intelligence, and predictive models.

Implant and construct decision-making in metastatic spine tumour surgery: a review of current concepts with a decision-making algorithm

STUDY DESIGN

Narrative Review.

OBJECTIVE

Metastatic spine tumour surgery (MSTS) is an important treatment modality of metastatic spinal disease (MSD). Increase in MSTS has been due to improvements in our oncological treatment, as patients have increased longevity and even those with poorer comorbidities are now being considered for surgery. However, there is currently no guideline on how MSTS surgeons should select the appropriate levels to instrument, and which type of implants should be utilised.

METHODS

The current literature on MSTS was reviewed to study implant and construct decision making factors, with a view to write this narrative review. All studies that were related to instrumentation in MSTS were included.

RESULTS

A total of 58 studies were included in this review. We discuss novel decision-making models that should be taken into account when planning for surgery in patients undergoing MSTS. These factors include the quality of bone for instrumentation, the extent of the construct required for MSTS patients, the use of cement augmentation and the choice of implant. Various studies have advocated for the use of these modalities and demonstrated better outcomes in MSTS patients when used appropriately.

CONCLUSION

We have established a new instrumentation algorithm that should be taken into consideration for patients undergoing MSTS. It serves as an important guide for surgeons treating MSTS, with the continuous evolvement of our treatment capacity in MSD.

LEVEL OF EVIDENCE IV

Incidence of Cement Leakage and Potential Risk Factors in Surgery for Spinal Metastasis: A Systematic Review and Meta-Analysis

OBJECTIVES

The current meta-analysis was performed to gather available evidence regarding the incidence and risk factors of cement leakage (CL) in patients undergoing surgical procedures for spinal metastasis.

METHODS

Two authors independently searched the PubMed, Embase, and CENTRAL databases. Clinical studies reporting the incidence or risk factors of CL were included for analysis. The primary outcome analyzed was the incidence of various types of CL. Random-effects or fixed-effects single-proportion meta-analyses were conducted to pool the available evidence, based on the heterogeneity test. Subgroup analyses were conducted based on surgical procedures (percutaneous vertebroplasty, percutaneous kyphoplasty, and others). Risk factors of CL were synthesized narratively to identify the most commonly accepted factors.

RESULTS

A total of 26 studies, involving 2551 patients, were included. The number of operated spine segments was reported in 23 studies, accounting for 4101 vertebrae. The pooled incidences of general, intradiscal, paravertebral, spinal canal, and intravascular CLs were 0.18 (95% confidence interval [CI], 0.11-0.28), 0.14 (95% CI, 0.08-0.21), 0.13 (95% CI, 0.06-0.21), 0.11 (95% CI, 0.05-0.19), and 0.12 (95% CI, 0.08-0.17), respectively. Subgroup analyses revealed significantly different incidences of general CL (0.37 vs. 0.06 vs. 0.09, P < 0.01), intradiscal CL (0.22 vs. 0.06 vs. 0.12, P < 0.01), paravertebral CL (0.25 vs. 0.03 vs. 0.06, P < 0.01), and vascular CL (0.14 vs. 0.03 vs. 0.15, P < 0.01) among the three groups. Posterior wall disruption, pathologic fracture, and the number of treated vertebral levels were the most commonly identified independent risk factors for general CL. Posterior wall disruption was determined as a common significant risk factor for spinal canal CL.

CONCLUSIONS

This review provides insights into the incidence and risk factors associated with CL in surgical procedures for spinal metastasis. Understanding these risk factors can contribute to the development of tailored strategies aimed at minimizing CL occurrence and optimizing surgical outcomes for patients undergoing spinal metastatic surgery.

The Role of Vertebral Augmentation Procedures in the Management of Multiple Myeloma

Approximately 90% of patients with multiple myeloma experience significant pain from osseous involvement during their lifetime. Untreated osseous involvement results in vertebral compression fractures, leading to negative consequences for quality of life. Vertebral augmentation procedures, including percutaneous vertebroplasty and kyphoplasty, offer better and faster pain control and likely lower morbidity compared with non-operative interventions. Our review provides an up-to-date summary of the indications, contraindications, timing, outcomes, and potential complications of vertebral augmentation procedures to guide practicing oncologists in effectively managing bone disease in patients with multiple myeloma.

Diabetes-related Screw Loosening: The Distinction of Surgical Sites and the Relationship among Diabetes, Implant Stabilization and Clinical Outcomes

OBJECTIVES

Diabetes mellitus (DM) is correlated with poor clinical outcomes in spinal surgery. However, the effect of it on screw stabilization has not been investigated. The aim of this study was to evaluate the screw loosening rate and postoperative outcomes in diabetic patients and to identify potential risk factors associated with loosening.

METHODS

This was a retrospective study. Two hundred and forty-three patients who received cervical or lumbar internal fixation between 2015 and 2019 were enrolled. Screw loosening was assessed on radiography, and clinical outcomes were evaluated by the improvement of visual analogue scale (VAS), Oswestry disability index (ODI) or Japanese Orthopaedic Association (JOA) scores. The relationship of DM, screw loosening and clinical outcomes were analyzed with chi-square tests and regression analyses.

RESULTS

One hundred and twenty-two patients (50.2%) with diabetes were included in this study. Diabetes led to the increase of the rate of screw loosening in the lumbar spine, while the loosening rate did not vary significantly in the cervical spine. The occurrence of screw loosening in the lumbar spine was more likely to be associated with clinical outcomes for motor performance including walking and sitting. However, no significant effect on JOA and VAS scores in the cervical spine of screw loosening was found. Moreover, the history of DM affected the outcomes of the patients who underwent spinal surgery.

CONCLUSION

DM had an adverse effect on screw stabilization. The impaired improvement of clinical outcomes in diabetics after spinal surgery was related to screw loosening. In addition to the direct effects on operative wounds and neural function, the impact on the screws due to DM was also worth noting.

Cardiopulmonary Cement Embolism Following Cement-Augmented Pedicle Screw Fixation: A Narrative Review

Fixation using cement-augmented pedicle screws (CAPS) is being increasingly performed. However, CAPS-associated cement leakage is a critical problem that can lead to cardiopulmonary cement embolism (CPCE). This narrative review aimed to explore the incidence of and risk factors and treatment strategies for CPCE and cement leakage-related complications after CAPS fixation. Data were extracted from each article, including characteristics of CPCE after CAPS fixation (incidence, location, diagnostic method and criteria, treatment, and outcome and prognosis). Overall, 28 case series and 14 case reports that met the inclusion criteria were included. Of the 1974 cases included in the review, CPCE was noted in 123, symptomatic CPCE in 35, and death in six, respectively. The frequencies of PCE and symptomatic PCE after CAPS fixation were 6% (range: 0-28.6%) and 1.3% (range: 0-26%), respectively. The range of frequencies of PCE and symptomatic PCE after CAPS fixation may have been wide because the definition of CPCE and data collection methods differed among the reports analyzed. Since PCE due to large cement emboli may be primarily related to the surgical technique, improved technique, such as minimizing the number of CAPSs by injecting low-volume high-viscosity cement at low velocity and pressure, and careful observation of cement leakage during CAPS insertion may reduce PCE associated with cement leakage. Spinal surgeons should pay more attention to the occurrence of CPCE during and after CAPS insertion, which can cause serious complications in some patients.

Biomechanical Comparison and Three-Dimensional Analysis of Cement Distribution Patterns for Different Pedicle Screw Designs

The purpose of this study to explore strategies for reducing cement leakage during cement-augmented pedicle screw fixation, we compared the cement distribution patterns and biomechanical strengths of different types of cement-augmented fenestrated screws and traditional cement-augmented techniques. We compared five screw groups in this study: (1) Cannulated screws (Cann); (2) distal one-hole screws (D1); (3) distal two-hole screws (D2); (4) middle two-hole screws (M2); and (5) traditional screws with a traditional cement injection technique (Trad). The screws were inserted into cancellous bone blocks using a controlled, adequate cement injection pressure (1.6–2.0 kg), and an appropriate cement viscosity. Center to screw tip distance, three-dimensional distribution, and pull-out strength for cement were compared between groups. The average distance between the cement center and the screw tip was highest in the M2 group, suggesting a higher risk of cement leakage into the spinal canal. The Trad group had the highest migration distance in the z-axis, also reflecting a higher risk of leakage into the spinal canal. The D1 group had the highest pull-out strength ( $253\pm 48.82\text{N}$ and $797\pm 58.31\text{N}$ ) in bone blocks representing different degrees of osteoporosis, and the D2 group had the second highest pull-out strength in the severe osteoporosis model. Overall, D1 screws appeared to be the best option for optimizing biomechanical function and minimizing the risk of cement leakage into the spinal canal in patients with osteoporotic bone undergoing spinal surgery.

Spinal metastasis: narrative reviews of the current evidence and treatment modalities

The treatment for spinal metastasis has evolved significantly during the past decade. An advancement in systemic therapy has led to a prolonged overall survival in cancer patients, thus increasing the incidence of spinal metastasis. In addition, with the improved treatment armamentarium, the prediction of patient survival using traditional prognostic models may have limitations and these require the incorporation of some novel parameters to improve their prognostic accuracy. The development of minimally-invasive spinal procedures and minimal access surgical techniques have facilitated a quicker patient recovery and return to systemic treatment. These modern interventions help to alleviate pain and improve quality of life, even in candidates with a relatively short life expectancy. Radiotherapy may be considered in non-surgical candidates or as adjuvant therapy for improving local tumour control. Stereotactic radiosurgery has facilitated this even in radioresistant tumours and may even replace surgery in radiosensitive malignancies. This narrative review summarizes the current evidence leading to the paradigm shifts in the modern treatment of spinal metastasis.

Hybrid Therapy (Surgery and Radiosurgery) for the Treatment of Renal Cell Carcinoma Spinal Metastases

BACKGROUND

The management of spinal metastatic renal cell carcinoma (mRCC) is controversial regarding extent of resection and radiation dosing.

OBJECTIVE

To determine outcomes in patients treated with hybrid therapy (separation surgery plus adjuvant stereotactic body radiation therapy [SBRT]) for mRCC.

METHODS

A retrospective study of a prospectively collected cohort of patients undergoing hybrid therapy for mRCC between 2003 and 2017 was performed. SBRT was delivered as high-dose single-fraction, high-dose hypofractionated, or low-dose hypofractionated. Extent of disease, clinical and operative outcomes, and complications data were collected, and associations with overall survival (OS) and progression-free survival were determined.

RESULTS

Ninety patients with mRCC with high-grade epidural spinal cord compression (ESCC grades 2 and 3) were treated. Metastases were widespread, oligometastatic, and solitary in 56%, 33%, and 11% of patients, respectively. SBRT delivered was high-dose single-fraction, high-dose hypofractionated, and low-dose hypofractionated in 24%, 56%, and 20% of patients, respectively. The 1-yr cumulative incidence of major complications was 3.4% (95% confidence interval [CI]: 0.0%-7.2%). The median follow-up was 14.2 mo for the entire cohort and 38.3 mo for survivors. The 1-yr cumulative incidence of progression was 4.6% (95% CI: 0.2%-9.0%), which translates to a local control rate of 95.4% (95% CI: 91.0%-99.8%) 1 yr after surgery. The median OS for the cohort was 14.8 mo.

CONCLUSION

These data support the use of hybrid therapy as a safe and effective strategy for the treatment of renal cell spine metastases.

Comparison of clinical effectiveness of fenestrated and conventional pedicle screws in patients undergoing spinal surgery: a systematic review and meta-analysis

INTRODUCTION

Pedicle screws are commonly used for spinal procedures for fusion stability, which is particularly important in osteoporotic patients, who are at an increased risk of requiring revision procedures.

AREAS COVERED

A systematic review and meta-analysis were conducted to compare clinical effectiveness of conventional pedicle screws (CPS) vs fenestrated pedicle screws (FPS) in patients undergoing spinal surgery. Primary outcomes included screw loosening, revision surgeries (involving an implant) and reoperations (not involving intervention on an implant) in patients treated with CPS vs FPS, sub-stratified by with and without osteoporosis. Secondary outcomes included changes in pain scores. Forty-eight studies with 8,302 patients were included, with 1,565 (19.18%) treated with FPS and 6,710 (80.82%) treated with CPS. FPS was associated with a lower risk of screw loosening (p = 0.001) vs CPS. In the general population, there was a non-significant trend of lower revision rate, but no difference in reoperation rate, between patients treated with FPS vs CPS. In osteoporotic patients, revision rates were significantly lower for FPS vs CPS (p = 0.009).

EXPERT OPINION

This review suggests that FPS are effective for surgical fixation and reduce rates of screw loosening, and in osteoporotic patients, revision surgeries, compared to CPS.