Minimally Invasive versus Open Surgery for Spinal Metastasis: A Systematic Review and Meta-Analysis

Survival and Prognostic Factors After Surgery in Single Spinal Metastasis: Comparison of Isolated-Single Spinal Metastasis and Single Spinal Metastasis With Other Metastasis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

This study aimed to evaluate the survival period in patients with a single spinal metastasis (SSM), subsequently comparing those with isolated-single spinal metastasis (I-SSM) and single spinal metastasis with other metastasis (O-SSM) after surgery, and to identify prognostic factors affecting their survival.

METHODS

A total of 135 patients were included, with 24 patients in the I-SSM group and 111 in the O-SSM group. Survival analysis was utilized to assess the survival of SSM patients, followed by a comparison of survival rates between the two groups. Univariate and multivariate analyses were conducted to identify significant prognostic factors for survival.

RESULTS

The overall median survival period for patients with single spinal metastasis (SSM) was 10.2 ± 1.8 months. Specifically, the median survival was 15.7 ± 5.7 months in the I-SSM group and 10.2 ± 1.5 months in the O-SSM group. The difference in survival periods between the two groups was not statistically significant (P = 0.345). Significant independent prognostic factors for survival included preoperative Karnofsky Performance Status (KPS) of 50 - 70 (OR 0.51, P = 0.017) and 80 - 100 (OR 0.46, P = 0.012), postoperative ambulatory status (OR 1.19, P = 0.028), and primary malignancy site [Group B (OR 2.67, P = 0.021), Group C (OR 2.90, P = 0.016)].

CONCLUSIONS

Patients with SSM have a median survival of 10.2 months, with no significant difference in postoperative survival between the I-SSM and O-SSM groups. Significant prognostic factors influencing the survival period after surgery include preoperative KPS, postoperative ambulatory status, and the primary malignancy site.

Surgical Interventions Following Radiotherapy in Spinal Metastases with Intermediate Instability: A Risk Factor Analysis: The Korean Society of Spinal Tumor Multicenter Study (KSST 2022-02)

BACKGROUND

One important determinant in choosing a treatment modality is spinal instability. Clear management guidelines are suggested for stable and unstable spinal metastatic lesions, but lesions in the intermediate instability category (SINS [spinal instability neoplastic score] score of 7-12) remain a clinical dilemma. This study aims to analyze the risk factors necessitating surgical intervention after radiotherapy (RT) in patients with those lesions.

METHODS

A multicenter cohort of 469 patients with spinal metastases of intermediate instability who received radiotherapy (RT) as the initial treatment between 2019 and 2021 were retrospectively enrolled. All patients were neurologically intact at the time of RT. According to the performance of surgical intervention after RT, various clinical and radiographic risk factors for surgical intervention were compared between surgery and non-surgery groups using uni- and multivariate analyses. A recursive partitioning analysis (RPA) was performed using significant determinants identified in multivariate analysis.

RESULTS

The mean age at the time of RT was 59.9 years and there were 198 females. The lung was the most common primary site. During the mean follow-up duration of 18.2 months, surgical treatment was required in 79 (17.9%) of patients. The most common surgical method was decompressive laminectomy with stabilization (62.0%), followed by vertebrectomy with stabilization (22.8%) and stabilization only (15.2%). The mean SINS for the total cohort was 9.0. Multivariate regression analyses revealed that the primary tumor site of the lung, liver, and kidney, higher Bilsky grades of ESCC, lytic bone lesions, and higher EQD210 were significant risk factors for surgical intervention after RT. Among them, Bilsky grade, primary tumor type of the lung, liver, and kidney, and EQD210 were the most important determinants for expecting the probability of surgical intervention on RPA.

CONCLUSIONS

Surgical intervention was performed in 17.9% of patients with intermediate instability after RT as the initial treatment. The primary tumor site of the lung, liver, and kidney, higher Bilsky grade of ESCC, and EQD210 were the most important determinants for expecting the probability of surgical intervention. Therefore, the optimal treatment strategy needs to be devised by carefully evaluating the risk of surgical intervention.

Learning Curve of Biportal Endoscopic Spinal Surgery: A Retrospective 2-Center Study

OBJECTIVE

Biportal endoscopic spinal surgery (BESS) technique is a novel, useful, and minimally invasive therapeutic strategy for lumbar degenerative diseases, which has advantages over other surgical techniques. However, the degree of technical difficulty in learning BESS is controversial and not well established. This study aims to determine the learning curve of BESS technique through cumulative sum (CUSUM) analysis.

METHODS

A total of 144 consecutive patients who underwent BESS with lumbar decompressive discectomy between 2017 and 2023 were included. A retrospective bicenter study was performed.

RESULTS

Three doctors with endoscopy experience employed the BESS technique for 51, 42, and 46 procedures, respectively. The CUSUM test of the 3 doctors showed adequate technical ability at the 45th, 41st, and 44th operations respectively. Two doctors without endoscopy experience gave up further use of BESS technique due to technical difficulties after initial attempt. The overall complication rates of the 3 surgeons using the BESS technique were 3.92% (n = 2), 6.82% (n = 3), and 2.17% (n = 1), respectively.

CONCLUSIONS

Our study demonstrated that BESS is an effective treatment, and the learning curves of BESS for lumbar discectomy using CUSUM analysis were 41 ∼ 45 cases in trainees with endoscopic experience. Endoscopic experience contributes to the learning curve of the BESS technique.

The role of minimally invasive surgery within a multidisciplinary approach for patients with metastatic spine disease over a decade: A systematic review

BACKGROUND

Metastatic spine disease (MSD) occurs commonly in cancer patients causing pain, spinal instability, devastating neurological compromise, and decreased quality of life. Oncological patients are often medically complex and frail, precluding them form invasive procedures. To address this issue, minimally invasive spinal surgery (MISS) techniques are desirable. The aim of this study is to review published peer-reviewed literature and ongoing clinical trials to provide current state of the art.

METHODS

A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, assessing MISS in MSD patients for the period 2013-2023. Innovations under development were assessed by querying and reviewing data from currently enrolling U.S. registered clinical trials.

RESULTS

From 3,696 articles, 50 studies on 3,196 patients focused on spinal oncology MISS. The most commonly reported techniques were vertebral augmentation (VA), percutaneous spinal instrumentation, and radiofrequency ablation (RFA). Surgical instrumentation/stabilization techniques were reported in 10/50 articles for a total of 410 patients. The majority of studies focused on pain as a primary outcome measure, with 28/50 studies reporting a significant improvement in pain following intervention. In the United States, 13 therapeutic trials are currently recruiting MSD patients. Their main focus includes radiosurgery, VA and/or RFA, and laser interstitial thermal therapy.

CONCLUSIONS

Due to their medical complexity and increased fragility, MSD patients may benefit from minimally invasive approaches. These strategies are effective at mitigating pain and preventing neurological deterioration, while providing other advantages including ease to start/resume systemic/radiotherapy treatment(s).

Predictor of Postoperative Ambulatory Recovery in Metastatic Spinal Cord Compression with Delayed Surgical Timing and Progressive Paraplegia

OBJECTIVE

To analyze preoperative predictors of ambulatory recovery after surgical treatment in metastatic spinal cord compression (MSCC) patients with delayed surgical timing and progressive paraplegia.

METHODS

We reviewed patients with a preoperative lower-extremity motor grade of ≤3 and surgical timing ≥48 hours after the nonambulatory status. The recovery group (group R) and nonrecovery group (group NR) were classified according to ambulation assessment during follow-up. The data on patient demographics, origin of the primary tumor, pre and postoperative chemotherapy and radiation therapy, surgical procedures, Tokuhashi score, Karnofsky score, preoperative lower-extremity motor grade, and surgical timing were collected for analyzing predictors of postoperative ambulatory recovery.

RESULTS

Of the 55 patients, 24 (43.6%) were group R and 31 patients were group NR. The preoperative motor grade of the lower extremities was the only predictive factor (P < 0.05). The mean hip flexor and knee extensor motor grades in group R were 2.0 ± 1.0 and 2.4 ± 1.1 respectively, while in group NR, they were 1.2 ± 1.0 and 1.3 ± 1.0. The odds ratios for failing to regain ambulatory ability were 12.6 in the knee extensor and 4.8 in the hip flexor when the motor grades 0-2 and 3 groups were compared. The rescue ratio of the preoperative hip flexor and knee extensor motor grade 0-2 group were 34.1% and 21.2%, grades 3 group were 71.4% and 77.3%, respectively.

CONCLUSIONS

The significant predictive factor for ambulatory recovery was the preoperative lower-extremity motor grade. The preoperative knee extensor motor grade was identified as a more important factor than hip flexor motor grade in predicting ambulatory recovery.

Safety and feasibility of ultra-long construct navigated minimally invasive spine surgery with adjuvant radiotherapy in extensive spinal metastasis : a comparative analysis

BACKGROUND

Our study compares the outcomes of extensive spinal metastasis patients treated with Ultra-Long Construct Navigated Minimally Invasive Spine Surgery (UNMISS) with Adjuvant Radiotherapy to those receiving only radiotherapy. Spinal metastasis often necessitates interventions like radiotherapy, chemotherapy, or surgery, with an increasing trend towards surgical management. minimally invasive spine surgery has demonstrated advantages over traditional open surgery, with fewer complications and better postoperative outcomes. Radiotherapy continues as a standard for those unsuitable for surgery.

METHODS

This retrospective study included extensive spinal metastasis patients treated between January 2017 and December 2020. We compared patients undergoing UNMISS in conjunction with radiotherapy to patients receiving radiotherapy alone, evaluating demographic data, disease characteristics, and treatment outcomes (VAS, survival) to establish statistical significance.

RESULTS

Twenty-three patients were included in our study. Fourteen patients underwent UNMISS, and nine patients received radiotherapy alone. There was no difference in baseline characteristics of patients. The longest construct in our case series involved T1 to iliac. Both cohorts showed significant improvement in pain scores post-treatment (p = 0.01). However, the UNMISS group demonstrated significantly lower post-treatment VAS scores (p = 0.003), indicating enhanced pain relief. Survival outcomes did not differ significantly between the two groups.

CONCLUSION

The UNMISS should be considered as an alternative treatment in a patient with symptomatic extensive spinal metastasis. The primary goal of this technique is to stabilize the multiple levels of spinal metastasis and decompression of the neural element if needed. This technique is safe and has a better outcome in pain improvement than the patient who received radiotherapy alone.

When Should Spinal Surgery Be Considered for Spinal Metastasis from Non-Small Cell Lung Cancer?-Propensity Score Matched Study between Surgery with Radiotherapy and Radiotherapy Alone

(1) Background: Although metastatic spine disease is increasing, the debate on therapeutic modality remains due to the heterogeneity of tumors and patients. This study aims to evaluate the efficacies of surgery and risk factors for patients' survival from potentially unstable spinal metastasis of non-small cell lung cancer; (2) Methods: Twenty-two patients undergoing surgery and radiotherapy (group I) were compared with 22 patients undergoing radiotherapy alone (group II) using propensity score matching in a 1-to-1 format. Clinical outcomes included the performance status and ambulatory status. In addition, independent risk factors for patients' survival were evaluated, including the molecular targeted therapy for mutations; (3) Results: deterioration in neurologic status was only observed in group II compared to group I (22.7% vs. 0%, p-value = 0.018). In addition, five patients in the surgery group showed improved Frankel grades. Regarding the patients' survival, a smoking history of more than ten pack-years (hazard ratio (HR) = 12.18), worse performance status (HR = 6.86), and absence of mutations (HR = 3.39) were the independent risk factors; (4) Conclusions: Spinal surgery with radiotherapy could have advantages for improving the neurologic status including ambulation for potentially unstable spine due to metastasis. Thus, surgery should be considered for patients with a longer life expectancy resulting from better performance status and use of the targeted therapy.

Percutaneous Vertebral Reconstruction (PVR) Technique of Pathological Compression Fractures: An Innovative Combined Treatment of Microwave Ablation, Bilateral Expandable Titanium SpineJack Implants Followed by Vertebroplasty

(1) Background: to retrospectively evaluate safety and efficacy of combined microwave ablation (MWA) and bilateral expandable titanium SpineJack (SJ) implants followed by vertebroplasty (VP) for the treatment of painful thoracolumbar pathological vertebral compression fracture. (2) Methods: from July 2017 to October 2022, twenty-eight patients (13 women and 15 men; mean age 68 ± 11 years) with a history of primary neoplasm and thirty-six painful vertebral metastases with vertebral compression fracture underwent combined MWA and bilateral expandable titanium SpineJack implants with vertebroplasty. We analyzed safety through complications rate, and efficacy through vertebral height restoration and pain decrease, evaluated using a visual analogue scale (VAS), and Functional Mobility Scale (FMS), and local tumor control. Contrast-enhanced CT scans were performed at 1, 3, and 6 months and a contrast-enhanced spine MRI at 6 months after the procedure. (3) Results: Technical success rate was 100%. No procedure-related major complications or death occurred. Vertebral height restoration was observed in 22 levels (58%), with a mean anterior height restoration of 2.6 mm ± 0.6 and a mean middle height restoration of 4.4 mm ± 0.6 (p < 0.001). Mean VAS score of pain evaluation on the day before treatment was 6.3 ± 1.5 (range 4-9). At the 6-month evaluation, the median VAS score for pain was 0.4 ± 0.6 (range 0-2) with a mean reduction of 93.65% (6.8 ± 0.7 vs. 0.4 ± 0.6; p < 0.000) compared with baseline evaluation. Contrast-enhanced CT scans were performed at 1, 3, and 6 months and a contrast-enhanced spine MRI was performed at 6 months after the procedure, showing no local recurrence, implant displacement, or new fractures in the treated site. (4) Conclusions: combined microwave ablation and bilateral expandable titanium SpineJack implants with vertebroplasty is a safe and effective procedure for the treatment of pathological compressive vertebral fractures. The vertebral stabilization achieved early and persistent pain relief, increasing patient mobility, improving recovery of walking capacity, and providing local tumor control.

Trends in Survival and Surgical Methods in Patients Surgically Treated for Metastatic Spinal Tumors: 25-Year Experience in a Single Institution

Background

This study aimed to examine trends in postoperative survival and surgical methods over a 25-year period in patients surgically treated for metastatic spinal tumors.

Methods

We performed a retrospective study of patients who underwent surgical treatment for metastatic spinal tumors between 1996 and 2020. For trend analysis, the study cohort was divided into three groups according to the year of surgery: 1996-2004, 2005-2012, and 2013-2020. A Kaplan-Meier survival analysis was performed to examine survival, and the log-rank test was used to compare the survival of the top six common cancers among the periods. The surgical methods were grouped and examined as follows: fixation only, palliative decompression and fixation, gross total removal and fixation, and total en bloc spondylectomy.

Results

This study included a total of 608 patients. There were 78 patients in 1996-2004, 236 in 2005-2012, and 294 in 2013-2020. Regarding the overall survival trend, the group 2013-2020 had a significantly improved survival as compared to the other two groups (p < 0.001). According to specific cancer sites, significant survival improvement was observed in patients with lung, kidney, and breast cancers (p < 0.001, p < 0.001, and p = 0.022, respectively). There were no significant changes in the primary sites of the liver, colorectum, or prostate. Regarding surgical methods, the proportion of gross total tumor removal declined, whereas the proportion of palliative decompression and fixation and fixation only procedures increased.

Conclusions

During the past 25 years, significant survival improvement was observed in patients with lung, kidney, and breast cancers. There was no improvement in survival in patients with liver, colorectal, and prostate cancers. In terms of surgical techniques, palliative decompression and fixation only procedures increased, while gross total tumor removal declined.

Factors affecting the prognosis of recovery of motor power and ambulatory function after surgery for metastatic epidural spinal cord compression

OBJECTIVE

Metastatic epidural spinal cord compression (MESCC) causes neurological deficits that may hinder ambulation. Understanding the prognostic factors associated with increased neurological recovery and regaining ambulatory functions is important for surgical planning in MESCC patients with neurological deficits. The present study was conducted to elucidate prognostic factors of neurological recovery in MESCC patients.

METHODS

A total of 192 patients who had surgery for MESCC due to preoperative neurological deficits were reviewed. A motor recovery rate ≥ 50% and ambulatory function restoration were defined as the primary favorable endpoints. Factors associated with a motor recovery rate ≥ 50%, regaining ambulatory function, and patient survival were analyzed.

RESULTS

About one-half (48.4%) of the patients had a motor recovery rate ≥ 50%, and 24.4% of patients who were not able to walk due to MESCC before the surgery were able to walk after the operation. The factors "involvement of the thoracic spine" (p = 0.015) and "delayed operation" (p = 0.041) were associated with poor neurological recovery. Low preoperative muscle function grade was associated with a low likelihood of regaining ambulatory functions (p = 0.002). Furthermore, performing the operation ≥ 72 hours after the onset of the neurological deficit significantly decreased the likelihood of regaining ambulatory functions (p = 0.020). Postoperative ambulatory function significantly improved patient survival (p = 0.048).

CONCLUSIONS

Delayed operation and the involvement of the thoracic spine were poor prognostic factors for neurological recovery after MESCC surgery. Furthermore, a more severe preoperative neurological deficit was associated with a lesser likelihood of regaining ambulatory functions postoperatively. Earlier detection of motor weaknesses and expeditious surgical interventions are necessary, not only to improve patient functional status and quality of life but also to enhance survival.

Recent Updates on Minimally Invasive Spine Surgery: Techniques, Technologies, and Indications

A number of minimally invasive spine surgeries (MISSs) have been developed to address the drawbacks of open spine surgery. Their advantages include small skin incisions, reduction in tissue damage, quick recovery, and short hospital stay. However, the clinical outcomes are comparable to open surgery. There was a cap on the number of indications that could be set for all spinal illnesses. The indications for MISSs have been expanding owing to mechanical and technological advances in medical equipment. Thus, this review presents the various MISSs developed to date, surgical indications, surgical techniques, and their advantages and disadvantages.

Epidemiology of spinal metastases, metastatic epidural spinal cord compression and pathologic vertebral compression fractures in patients with solid tumors: A systematic review

Introduction

Spinal metastases (SM) are a frequent complication of cancer and may lead to pathologic vertebral compression fractures (pVCF) and/or metastatic epidural spinal cord compression (MESCC). Based on autopsy studies, it is estimated that about one third of all cancer patients will develop SM. These data may not provide a correct estimation of the incidence in clinical practice.

Objective

This systematic review (SR) aims to provide a more accurate estimation of the incidence of SM, MESCC and pVCF in a clinical setting.

Methods

We performed a SR of papers regarding epidemiology of SM, pVCF, and MESCC in patients with solid tumors conform PRISMA guidelines. A search was conducted in the PubMed and Web of Science database using the terms epidemiology, prevalence, incidence, global burden of disease, cost of disease, spinal metastas*, metastatic epidural spinal cord compression, pathologic fracture, vertebral compression fracture, vertebral metastas* and spinal neoplasms. Papers published between 1975 and august 2021 were included. Quality was evaluated by the STROBE criteria.

Results

While 56 studies were included, none of them reports the actual definition used for MESCC and pVCF, inevitably introducing heterogenity. The overall cumulative incidence of SM and MESCC is 15.67% and 2.84% respectively in patients with a solid tumor. We calculated a mean cumulative incidence in patients with SM of 9.56% (95% CI 5.70%-13.42%) for MESCC and 12.63% (95% CI 7.00%-18.25%) for pVCF. Studies show an important delay between onset of symptoms and diagnosis.

Conclusions

While the overall cumulative incidence for clinically diagnosed SM in patients with a solid tumor is 15.67%, autopsy studies reveal that SM are present in 30% by the time they die, suggesting underdiagnosing of SM. Approximately 1 out of 10 patients with SM will develop MESCC and another 12.6% will develop a pVCF. Understanding these epidemiologic data, should increase awareness for first symptoms, allowing early diagnosis and subsequent treatment, thus improving overall outcome.