A Novel Use of the Intraoperative MRI for Metastatic Spine Tumors

3-D Brain Reconstruction by Hierarchical Shape-Perception Network From a Single Incomplete Image

3-D shape reconstruction is essential in the navigation of minimally invasive and auto robot-guided surgeries whose operating environments are indirect and narrow, and there have been some works that focused on reconstructing the 3-D shape of the surgical organ through limited 2-D information available. However, the lack and incompleteness of such information caused by intraoperative emergencies (such as bleeding) and risk control conditions have not been considered. In this article, a novel hierarchical shape-perception network (HSPN) is proposed to reconstruct the 3-D point clouds (PCs) of specific brains from one single incomplete image with low latency. A branching predictor and several hierarchical attention pipelines are constructed to generate PCs that accurately describe the incomplete images and then complete these PCs with high quality. Meanwhile, attention gate blocks (AGBs) are designed to efficiently aggregate geometric local features of incomplete PCs transmitted by hierarchical attention pipelines and internal features of reconstructing PCs. With the proposed HSPN, 3-D shape perception and completion can be achieved spontaneously. Comprehensive results measured by Chamfer distance (CD) and PC-to-PC error demonstrate that the performance of the proposed HSPN outperforms other competitive methods in terms of qualitative displays, quantitative experiment, and classification evaluation.

Neurosurgical Ablation for Pain: A Technology Review

Neurosurgical ablative procedures for pain have dramatically transformed over the years. Compared to their precursors, present day techniques are less invasive and more precise as a result of advances in both device engineering and imaging technology. From a clinical perspective, understanding the strengths and drawbacks of modern techniques is necessary to optimize patient outcomes. In this review, we provide an overview of the major contemporary neuroablative modalities/technologies used for treating pain. We will compare and contrast these modalities from one another with respect to their intraoperative monitoring needs, invasiveness, range of access, and lesion generation. Finally, we will provide a brief commentary on the future of neuroablation given the advent of neuromodulation options for pain control.

Evolution of surgical treatment of metastatic spine tumors

PURPOSE

The treatment of cancer has transformed over the past 40 years, with medical oncologists, radiation oncologists and surgeons working together to prolong survival times and minimize treatment related morbidity. With each advancement, the risk-benefit scale has been calibrated to provide an accurate assessment of surgical hazard. The goal of this review is to look back at how the role of surgery has evolved with each new medical advance, and to explore the role of surgeons in the future of cancer care.

METHODS

A literature review was conducted, highlighting the key papers guiding surgical management of spinal metastatic lesions.

CONCLUSION

The roles of surgery, medical therapy, and radiation have evolved over the past 40 years, with new advances requiring complex multidisciplinary care.

Minimally Invasive Surgery for Spinal Metastasis: A Review

OBJECTIVE

Minimally invasive surgery (MIS) techniques have advanced the treatment of metastatic diseases to the spine. The objective of this review is to describe clinical outcomes, benefits, and complications of these techniques.

METHODS

All relevant clinical studies describing the role of MIS, computer-assisted navigation (CAN), robot-assisted (RA) procedures, and laser interstitial thermal therapy (LITT) in the treatment of metastatic spine diseases were identified from PubMed, MEDLINE, and relevant article bibliographies.

RESULTS

For MIS articles, we filtered 1480 results and identified 26 studies. For CAN, we searched 464 articles to identify 18 articles for review. For RA, we searched 321 results to identify 7 studies for review. For LITT, we identified 21 articles for review.

CONCLUSIONS

MIS for the treatment of spine metastasis has significant potential benefits in reducing surgical site infections, hospital stay, and blood loss without compromising instrument accuracy or overall outcomes. Overall, MIS and its adjuncts have the potential to reduce the risks involved in the treatment of patients with metastatic disease to the spinal column without compromising the benefits of decompression and stabilization of the spine.

Spinal metastases 2021: a review of the current state of the art and future directions

Spinal metastases are an increasing societal health burden secondary to improvements in systemic therapy. Estimates indicate that 100,000 or more people have symptomatic spine metastases requiring management. While open surgery and external beam radiotherapy have been the pillars of treatment, there is growing interest in more minimally invasive technologies (eg separation surgery) and non-operative interventions (eg percutaneous cementoplasty, stereotactic radiosurgery). The great expansion of these alternatives to open surgery and the prevalence of adjuvant therapeutic options means that treatment decision making is now complex and reliant upon multidisciplinary collaboration. To help facilitate construction of care plans that meet patient goals and expectations, clinical decision aids and prognostic scores have been developed. These have been shown to have superior predictive value relative to more classic prediction models and may become an increasingly important aspect of the clinical practice of spinal oncology. Here we overview current therapeutic advances in the management of spine metastases and highlight emerging areas for research. Given the rapid advancements in surgical technologies and adjuvants, the field is likely to undergo further transformative changes in the coming decade.

Metastatic Renal Cell Carcinoma to the Spine: Outcomes and Morbidity: Single-Center Experience

BACKGROUND

Renal cell carcinoma with metastases to the spine (RCCMS) requires a multidisciplinary approach. We reviewed our institutional experience with RCCMS patients undergoing spinal surgery in order to identify factors that may affect clinical outcomes, survival, and complications.

METHODS

Patients with RCCMS who underwent operative intervention from 2007 to 2020 were reviewed retrospectively.

RESULTS

Forty-four patients with the diagnosis of RCCMS were identified. Pain was the most common symptom, and neurologic dysfunction was present in one third of cases. Thoracic spine was the most common location (N = 27), followed by the lumbar (N = 12) and cervical (N = 5) regions. The overall survival from diagnosis of renal cell carcinoma was 25 (2 - 194) months and 8 (0.3 - 92) months after spinal surgery. Gender, age, spinal level, postoperative radiation, and nephrectomy had no bearing on survival. Survival for patients with a Tokuhashi score of 0 - 8, 9 - 11, and 12 - 15 was 6.5 (1.5 - 23.5), 8.9 (0.3 - 91.6), and 23.4 (2.5 - 66) months, respectively (P = 0.03). The postoperative American Spinal Cord Injury Association score of E (hazard ratio 0.109 [95% confidence interval 0.022 - 0.534, P = 0.006) also bore a significant influence on survival. There was a total of 10 complications in 7 of 44 (16%) patients.

CONCLUSIONS

Median postoperative survival of patients with RCCMS was 8 (0.3 - 92) months. Higher Tokuhashi score and ASIA E score at follow-up correlated with improved overall survival. Complication rate was 16%. Spinal surgery in RCCMS is indicated for the preservation of function and prevention of neurologic deterioration. Multimodality therapy with improved chemotherapy and stereotactic spinal radiation is expected to impact quality and length of survival positively.

Novel Applications of Spinal Navigation in Deformity and Oncology Surgery-Beyond Screw Placement

Computer-assisted navigation has made a major impact on spine surgery, providing surgeons with technological tools to safely place instrumentation anywhere in the spinal column. With advances in intraoperative image acquisition, registration, and processing, many surgeons are now using navigation in their practices. The incorporation of navigation into the workflow of surgeons continues to expand with the evolution of minimally invasive techniques and robotic surgery. While numerous investigators have demonstrated the benefit of navigation for improving the accuracy of instrumentation, few have reported applying this technology to other aspects of spine surgery. Surgeries to correct spinal deformities and resect spinal tumors are technically demanding, incorporating a wide range of techniques not only for instrumentation placement but also for osteotomy planning and executing the goals of surgery. Although these subspecialties vary in their objectives, they share similar challenges with potentially high complications, invasiveness, and consequences of failed execution. Herein, we highlight the utility of using spinal navigation for applications beyond screw placement: specifically, for planning and executing osteotomies and guiding the extent of tumor resection. A narrative review of the work that has been done is supplemented with illustrative cases demonstrating these applications.

The History of Neurosurgical Spinal Oncology: From Inception to Modern-Day Practices

The neurosurgical management of spinal neoplasms has undergone immense development in parallel with advancements made in general spine surgery. Laminectomies were performed as the first surgical procedures used to treat spinal neoplasms. Since then, neurosurgical spinal oncology has started to incorporate techniques that have developed from recent advances in minimally invasive spine surgery. Neurosurgery has also integrated radiotherapy into the treatment of spine tumors. In this historical vignette, we present a vast timeline spanning from the Byzantine period to the current day and recount the major advancements in the management of spinal neoplasms.

Spinal laser interstitial thermal therapy: single-center experience and outcomes in the first 120 cases

OBJECTIVE

The objective of this study was to present the results of a consecutive series of 120 cases treated with spinal laser interstitial thermal therapy (sLITT) to manage epidural spinal cord compression (ESCC) from metastatic tumors.

METHODS

The electronic records of patients treated from 2013 to 2019 were analyzed retrospectively. Data collected included demographic, pathology, clinical, operative, and imaging findings; degree of epidural compression before and after sLITT; length of hospital stay; complications; and duration before subsequent oncological treatment. Independent-sample t-tests were used to compare means between pre- and post-sLITT treatments. Survival was estimated by the Kaplan-Meier method. Multivariate logistic regression was used to analyze predictive factors for local recurrence and neurological complications.

RESULTS

There were 110 patients who underwent 120 sLITT procedures. Spinal levels treated included 5 cervical, 8 lumbar, and 107 thoracic. The pre-sLITT Frankel grades were E (91.7%), D (6.7%), and C (1.7%). The preoperative ESCC grade was 1c or higher in 92% of cases. Metastases were most common from renal cell carcinoma (39%), followed by non-small cell lung carcinoma (10.8%) and other tumors (35%). The most common location of ESCC was in the vertebral body (88.3%), followed by paraspinal/foraminal (7.5%) and posterior elements (4.2%). Adjuvant radiotherapy (spinal stereotactic radiosurgery or conventional external beam radiation therapy) was performed in 87 cases (72.5%), whereas 33 procedures (27.5%) were performed as salvage after radiotherapy options were exhausted. sLITT was performed without need for spinal stabilization in 87 cases (72.5%). Post-sLITT Frankel grades were E (85%), D (10%), C (4.2%), and B (0.8%); treatment was associated with a median decrease of 2 ESCC grades. The local control rate at 1 year was 81.7%. Local control failure occurred in 25 cases (20.8%). The median progression-free survival was not reached, and overall survival was 14 months. Tumor location in the paraspinal region and salvage treatment were independent predictors of local recurrence, with hazard ratios of 6.3 and 3.3, respectively (p = 0.01). Complications were observed in 22 cases (18.3%). sLITT procedures performed in the lumbar and cervical spine had hazard ratios for neurological complications of 15.4 and 17.1 (p < 0.01), respectively, relative to the thoracic spine.

CONCLUSIONS

sLITT is safe and provides effective local control for high-grade ESCC from vertebral metastases in the thoracic spine, particularly when combined with adjuvant radiotherapy. The authors propose considering sLITT as an alternative to open surgery in selected patients with spinal metastases.

The intersection between immunotherapy and laser interstitial thermal therapy: a multipronged future of neuro-oncology

The rise of immunotherapy (IT) in oncological treatment has greatly improved outcomes in a number of disease states. However, its use in tumors of the central nervous system (CNS) remains limited for multiple reasons related to the unique immunologic tumor microenvironment. As such, it is valuable to consider the intersection of IT with additional treatment methods that may improve access to the CNS and effectiveness of existing IT modalities. One such combination is the pairing of IT with localized hyperthermia (HT) generated through technologies such as laser interstitial thermal therapy (LITT). The wide-ranging immunomodulatory effects of localized and whole-body HT have been investigated for some time. Hyperthermia has demonstrated immunostimulatory effects at the level of tumor cells, immune cells, and the broader environment governing potential immune surveillance. A thorough understanding of these effects as well as the current and upcoming investigations of such in combination with IT is important in considering the future directions of neuro-oncology.

A comparison of spinal laser interstitial thermotherapy with open surgery for metastatic thoracic epidural spinal cord compression

OBJECTIVE

The proximity of the spinal cord to compressive metastatic lesions limits radiosurgical dosing. Open surgery is used to create safe margins around the spinal cord prior to spinal stereotactic radiosurgery (SSRS) but carries the risk of potential surgical morbidity and interruption of systemic oncological treatment. Spinal laser interstitial thermotherapy (SLITT) in conjunction with SSRS provides local control with less morbidity and a shorter interval to resume systemic treatment. The authors present a comparison between SLITT and open surgery in patients with metastatic thoracic epidural spinal cord compression to determine the advantages and disadvantages of each method.

METHODS

This is a matched-group design study comprising patients from a single institution with metastatic thoracic epidural spinal cord compression that was treated either with SLITT or open surgery. The two cohorts defined by the surgical treatment comprised patients with epidural spinal cord compression (ESCC) scores of 1c or higher and were deemed suitable for either treatment. Demographics, pre- and postoperative ESCC scores, histology, morbidity, hospital length of stay (LOS), complications, time to radiotherapy, time to resume systemic therapy, progression-free survival (PFS), and overall survival (OS) were compared between groups.

RESULTS

Eighty patients were included in this analysis, 40 in each group. Patients were treated between January 2010 and December 2016. There was no significant difference in demographics or clinical characteristics between the cohorts. The SLITT cohort had a smaller postoperative decrease in the extent of ESCC but a lower estimated blood loss (117 vs 1331 ml, p < 0.001), shorter LOS (3.4 vs 9 days, p < 0.001), lower overall complication rate (5% vs 35%, p = 0.003), fewer days until radiotherapy or SSRS (7.8 vs 35.9, p < 0.001), and systemic treatment (24.7 vs 59 days, p = 0.015). PFS and OS were similar between groups (p = 0.510 and p = 0.868, respectively).

CONCLUSIONS

The authors' results have shown that SLITT plus XRT is not inferior to open decompression surgery plus XRT in regard to local control, with a lower rate of complications and faster resumption of oncological treatment. A prospective randomized controlled study is needed to compare SLITT with open decompressive surgery for ESCC.

Multicenter validation of automated trajectories for selective laser amygdalohippocampectomy

Objective

Laser interstitial thermal therapy (LITT) is a novel minimally invasive alternative to open mesial temporal resection in drug‐resistant mesial temporal lobe epilepsy (MTLE). The safety and efficacy of the procedure are dependent on the preplanned trajectory and the extent of the planned ablation achieved. Ablation of the mesial hippocampal head has been suggested to be an independent predictor of seizure freedom, whereas sparing of collateral structures is thought to result in improved neuropsychological outcomes. We aim to validate an automated trajectory planning platform against manually planned trajectories to objectively standardize the process.

Methods

Using the EpiNav platform, we compare automated trajectory planning parameters derived from expert opinion and machine learning to undertake a multicenter validation against manually planned and implemented trajectories in 95 patients with MTLE. We estimate ablation volumes of regions of interest and quantify the size of the avascular corridor through the use of a risk score as a marker of safety. We also undertake blinded external expert feasibility and preference ratings.

Results

Automated trajectory planning employs complex algorithms to maximize ablation of the mesial hippocampal head and amygdala, while sparing the parahippocampal gyrus. Automated trajectories resulted in significantly lower calculated risk scores and greater amygdala ablation percentage, whereas overall hippocampal ablation percentage did not differ significantly. In addition, estimated damage to collateral structures was reduced. Blinded external expert raters were significantly more likely to prefer automated to manually planned trajectories.

Significance

Retrospective studies of automated trajectory planning show much promise in improving safety parameters and ablation volumes during LITT for MTLE. Multicenter validation provides evidence that the algorithm is robust, and blinded external expert ratings indicate that the trajectories are clinically feasible. Prospective validation studies are now required to determine if automated trajectories translate into improved seizure freedom rates and reduced neuropsychological deficits.

The evolution of surgical management for vertebral column tumors

In BriefThere has been a significant shift in treatment paradigms for both primary and metastatic spine tumors over the last several decades. This article highlights some of the more important treatment advances that practitioners should be made aware of. It is important to not only incorporate these changes into individual practice but also appreciate the treatment trends that herald a significantly different future for spine tumor treatment.

MRI-Guided Cryoablation of Epidural Malignancies in the Spinal Canal Resulting in Neural Decompression and Regrowth of Bone

OBJECTIVE

The purpose of this article is to describe the use of MRI to safely monitor cryoablation for the treatment of spinal epidural malignancies.

CONCLUSION

Use of MRI guidance to monitor percutaneous cryoablation allows ablation margins more distinct than those allowed by heat-based ablation modalities. MRI-guided cryoablation is a feasible option for treating epidural tumors involving the spinal canal, resulting in successful decompression of the tumor away from the spinal cord with regrowth of previously eroded bone around the spinal canal.

Surgical management of spinal metastases

INTRODUCTION

Metastatic spinal disease is a source of significant morbidity in patients with cancer. Recent advancements in adjuvant oncologic therapy has led to increased survival for many patients who harbor neoplastic disease. As a result of this, the chance of developing metastatic spinal disease over the course of a cancer patient's lifespan has increased. Symptomatic metastatic spinal disease can cause significant morbidity including severe pain, neurologic deficit, and loss of ambulation. Current treatment of these patients typically involves the use of multiple modalities, including surgery, radiation, and chemotherapy. Areas covered: An extensive literature review was performed to support the author's opinion on the matter of surgical management of spinal metastatic disease. Pubmed was utilized as a primary search engine. Expert commentary: Despite advances in chemotherapy and radiation therapy, surgery remains a mainstay in many of these patients, particularly with those with either significant metastatic spinal epidural compression or spinal instability. This review discusses the surgical management of metastatic spinal disease including a framework for decision making and technical considerations when deciding to operate on these patients.