Ablation Zones and Weight-Bearing Bones: Points of Caution for the Palliative Interventionalist

Recent Advances in Minimally Invasive Management of Osteolytic Periacetabular Skeletal Metastases

Painful skeletal osteolytic metastases, impending pathological fractures, and nondisplaced fractures present as a devastating clinical problem in advanced stage cancer patients. Open surgical approaches provide excellent mechanical stabilization but are often associated with high complication rates and slow recovery times. Percutaneous minimally invasive interventions have arisen as a pragmatic and logical treatment option for patients with late-stage cancer in whom open surgery may be contraindicated. These percutaneous interventions minimize soft tissue dissection, allow for the immediate initiation or resumption of chemotherapies, and present with fewer complications. This review provides the most up-to-date technical and conceptual framework for the minimally invasive management of osseous metastases with particular focus on periacetabular lesions. Fundamental topics discussed are as follows: (1) pathogenesis of cancer-induced bone loss and the importance of local cytoreduction to restore bone quality, (2) anatomy and biomechanics of the acetabulum as a weight-bearing zone, (3) overview of ablation options and cement/screw techniques, and (4) combinatorial approaches. Future studies should include additional studies with more long-term follow-up to better assess mechanical durability of minimally invasive interventions. An acetabulum-specific functional and pain scoring framework should be adopted to allow for better cross-study comparison.

The New Ice Age of Musculoskeletal Intervention: Role of Percutaneous Cryoablation in Bone and Soft Tissue Tumors

In the rapidly evolving field of interventional oncology, minimally invasive methods, including CT-guided cryoablation, play an increasingly important role in tumor treatment, notably in bone and soft tissue cancers. Cryoablation works using compressed gas-filled probes to freeze tumor cells to temperatures below -20 °C, exploiting the Joule-Thompson effect. This cooling causes cell destruction by forming intracellular ice crystals and disrupting blood flow through endothelial cell damage, leading to local ischemia and devascularization. Coupling this with CT technology enables precise tumor targeting, preserving healthy surrounding tissues and decreasing postoperative complications. This review reports the most important literature on CT-guided cryoablation's application in musculoskeletal oncology, including sarcoma, bone metastases, and bone and soft tissue benign primary tumors, reporting on the success rate, recurrence rate, complications, and technical aspects to maximize success for cryoablation in the musculoskeletal system.

Interventional Palliation of Painful Extraspinal Musculoskeletal Metastases

The musculoskeletal system is commonly involved by metastases, and skeletal-related events such as intractable pain due to direct osseous tumor involvement, pathologic fracture, and neurologic deficits as a result of nerve compression often adversely affect patient's quality of life. There have been substantial advances in percutaneous minimally invasive musculoskeletal oncologic interventions for the management of patients with musculoskeletal metastases including thermal ablations, cementation with or without osseous reinforcement via implants, osteosynthesis, neurolysis, and palliative injections which are progressively incorporated in clinical practice. These interventions are performed, in conjunction with or supplemented by adjuvant radiation therapy, systemic therapy, surgery, or analgesics, to achieve durable pain palliation, local tumor control, or cure. This article reviews minimally invasive percutaneous image-guided musculoskeletal oncologic interventions for the management of patients with extraspinal musculoskeletal metastases.

Celiac Plexus Cryoneurolysis

Intractable, chronic abdominal pain from upper abdominal malignant and benign diseases is a significant challenge for healthcare providers and burden on the healthcare system. While opioid analgesics are commonly used to provide pain relief, the adverse effects of chronic opioid use cannot be overlooked. Celiac plexus neurolysis via chemical or thermal means represents an alternative minimally invasive approach to provide palliative pain relief and increase patients' quality of life. Through the use of computed tomography guidance, celiac plexus neurolysis can be performed by accurately targeting the celiac plexus, while minimizing risks to adjacent structures. Historically, celiac plexus neurolysis was performed via instillation of ethanol or phenol; however, within the past decade cryoablation has gained increasing use with potentially fewer side effects.

Ablation Techniques in Cancer Pain

Painful bone metastases are a frequently encountered problem in oncology practice. The skeletal system is the third most common site of metastatic disease and up to 85% of patients with breast, prostate, and lung cancer may develop bone metastases during the course of their disease.

Bone Metastases: State of the Art in Minimally Invasive Interventional Oncology

Bone is the third most common site involved by cancer metastases, and skeleton-related events such as intractable pain due to direct osseous tumor involvement, pathologic fracture, and neurologic deficits as a consequence of nerve or spinal cord compression often affect patients' functional independence and quality of life unfavorably. The annual medical-economic burden related to bone metastases is a substantial component of the total direct medical cost estimated by the National Institutes of Health. There have been substantial recent advances in percutaneous image-guided minimally invasive musculoskeletal oncologic interventions for the management of patients with osseous metastatic disease. These advances include thermal ablation, cementation with or without osseous reinforcement with implants, osteosynthesis, thermal and chemical neurolyses, and palliative injections, which are progressively incorporated into the management paradigm for such patients. These interventions are performed in conjunction with or are supplemented by adjuvant radiation therapy, systemic therapy, surgery, or analgesic agents to achieve durable pain palliation, local tumor control, or cure, and they provide a robust armamentarium for interventional radiologists to achieve safe and effective treatment in a multidisciplinary setting. In addition, these procedures are shifting the patient management paradigm in modern-era practice. The authors detail the state of the art in minimally invasive percutaneous image-guided musculoskeletal oncologic interventions and the role of radiologists in managing patients with skeletal metastases. ^©RSNA, 2021.

Trends in Musculoskeletal Ablation: Emerging Indications and Techniques

Image-guided percutaneous thermal ablation plays an increasingly important role in the multidisciplinary management of musculoskeletal lesions. Established indications for ablation in this setting include the treatment of osteoid osteomas, palliation of painful skeletal metastases, local control of oligometastatic disease, and consolidation of bone tumors at risk for fracture. Emerging indications include the treatment of symptomatic soft tissue masses such as extra-abdominal desmoid tumors and abdominal wall endometriosis. This review will discuss considerations in patient selection and preprocedural workup, ablation technology and techniques, strategies to avoid complications, and expected outcomes of ablation in the musculoskeletal system.

Natural History of Mixed and Motor Nerve Cryoablation in Humans-A Cohort Analysis

Eight patients who underwent percutaneous cryoablation of mixed and/or motor nerves over a period of 5 years were identified. Distances from the ablation sites to origins of distal musculature were measured, and times to initial clinical recovery were collected. Strength progression over time following muscle activation was also collected and analyzed. All patients demonstrated activation of all muscles distal to the ablation, and the calculated mean rate of nerve regeneration based on distance to the origin of the assessed musculature and time to muscle activation for the group was 1.5 mm/day ± 1.1.

Analgesia of percutaneous thermal ablation plus cementoplasty for cancer bone metastases

Background

The purpose of this study was to review recent research related to the analgesic effect of ablation therapy combined with cementoplasty, as well as to identify the duration of analgesic effect and risk for cement leaks.

Methods

A systematic literature search using PubMed, Web of Science, and annual meeting proceedings of the oncology society and other organizations were conducted.

Results

Twelve retrospective studies met the inclusion criteria. Four of the studies included in the review assessed the changes immediately after treatment. Five studies were subjected to analyses of analgesic effect of combined percutaneous thermal ablation and Cementoplasty at 24 weeks after treatment. Incidences of leakage of bone cement during surgery were detected in 4 out of 12 studies. The change of mean pain scores at 1 days, at 1 week, and at 4 weeks, 12 weeks, and 24 weeks after treatment were -3.90 (95% CI: -4.80 to -3.00), -4.55 (95% CI:-5.46 to -3.64), -4.78 (95% CI: -5.70 to -3.86), -5.16 (95% CI: -6.39 to -3.92), and -5.91 (95% CI: -6.63 to -5.19). The relative risk of cement leakage was 0.10 (95% CI: -6.63 to -5.19).

Conclusions

Our systematic review suggested that thermal ablation combined with cementoplasty could be a safe and effective intervention for the management of bone metastases-induced pain.

Percutaneous CT-Guided Cryovagotomy in Patients with Class I or Class II Obesity: A Pilot Trial

OBJECTIVE

This study evaluated the safety of percutaneous CT-guided cryoablation of the vagus nerve (percutaneous cryovagotomy) in participants with class I or class II obesity.

METHODS

The study was an open-label, single-group, prospective pilot investigation designed around safety-related stopping criteria. Twenty participants with 30 > BMI > 37 underwent percutaneous cryovagotomy with follow-up visits at day 7, 45, 90, and 180. Data related to adverse events, technical success, weight loss, quality of life, dietary intake, global impressions of hunger change, activity, and body composition were analyzed.

RESULTS

The procedural technical success rate was 100%. There were no adverse events in 19 participants who completed the trial. Ninety-five percent of patients reported decreased appetite following the procedure, and reductions in mean absolute weight and BMI were observed at all time points. The mean quality of life and activity scores improved from baseline to 6 months post procedure, and mean caloric intake and overall body fat decreased over the same period.

CONCLUSIONS

Percutaneous CT-guided cryovagotomy is feasible and was tolerated without complications or adverse events in this cohort. Quantitative preliminary data from this pilot investigation inform the design of a larger prospective randomized clinical trial.

Percutaneous image-guided cryoablation of painful bone metastases: A single institution experience

BACKGROUND

Bone metastases are frequently painful and may lead to various complications that can affect quality of life. While external beam radiation therapy is the standard first-line treatment, 20-30% of patients do not experience sufficient pain relief. Cryoablation is increasingly being used for the treatment of musculoskeletal metastases. The purpose of our retrospective study was to analyze pain relief and local disease control after percutaneous image-guided cryoablation (PCA) therapy of painful bone metastases.

MATERIALS AND METHODS

Sixteen patients treated with PCA for painful bone metastases (n=18) over a 5-year period (from June 2011 to June 2016) were retrospectively reviewed. Five patients also benefited from long bone fixation because of an impending fracture. We analyzed the impact of treatment on pain relief, using a numerical rating scale (NRS), and local disease control.

RESULTS

The mean follow-up period was 12 months (range, 1.5-39 months). At last oncological outpatient consultation, 75% (12/16) of patients had good pain relief, while 63% (10/16) had locally stable disease or no local recurrence of the treated bone metastases. The mean NRS score decreased significantly from 3.3 to 1.2 after PCA (p=0.0024). The five patients with concomitant long bone fixation all had satisfactory pain relief at the last follow-up visit.

CONCLUSION

PCA is a safe and valid treatment option for pain and local disease control in cases of painful bone metastases after failed standard first-line therapy. This technique can also be effectively associated to prophylactic long bone fixation and may allow for easier rehabilitation protocols when treating weight-bearing bones.

LEVEL OF EVIDENCE

IV, Retrospective case series.

Increasing Role of Image-Guided Ablation in the Treatment of Musculoskeletal Tumors

In the last decade, percutaneous treatment of musculoskeletal (MSK) tumors has become more established in routine clinical care while also undergoing a number of advancements. Ablative techniques to palliate painful skeletal metastases have gained wide acceptance, while goals for ablation have evolved to include local control of oligometastases and desmoid tumors. Bone consolidation or augmentation is now frequently used in conjunction with or instead of ablation of skeletal tumors to stabilize pathologic fractures or prevent further morbidity that could result from fractures caused by tumor progression. These procedures have traditionally been performed with cement injection, although additional percutaneous consolidation or stabilization devices have been developed. Techniques to monitor the ablation zone and adjacent structures intraprocedurally are now applied to increase the number of tumors amenable to treatment. These include methods to depict, displace, or monitor critical structures adjacent to targeted MSK tumors. Finally, the role of ablation in the comprehensive care of patients with MSK tumors continues to change with the evolving triage of patients between radiation therapy, surgical resection and stabilization, and percutaneous ablative and consolidative management.

Expanding role of percutaneous ablative and consolidative treatments for musculoskeletal tumours

Interventional approaches to musculoskeletal tumours have significantly changed over the last several years, and new treatments continue to be developed. All ablative modalities are currently applied to the treatment of bone tumours, including radiofrequency, cryo-, microwave, and laser ablation devices. Indications for ablation of bone and soft-tissue tumours have expanded beyond palliation of painful bone metastases and eradication of osteoid osteomas to the local control of oligometastatic disease from a number of primary tumours and ablation of desmoid tumours. In addition, tools for consolidation of bone tumours at risk of pathological fracture have also expanded. With these developments, ablation has become the primary treatment for osteoid osteomas and, at some institutions, desmoid tumours. It may be the primary or secondary treatment for palliation of painful bone tumours, frequently used in patients with pain refractory to or recurrent after radiation therapy. It is used as a treatment for limited metastatic disease or for metastases that grow disproportionately in patients with multifocal metastases, either in combination with systemic therapy or to reserve systemic therapy and its toxicity for more widespread disease progression. Moreover, percutaneous methods to consolidate bone at risk of fracture have become more commonplace, aided by techniques using materials beyond typical bone cement.

Pneumodissection for skin protection in image-guided cryoablation of superficial musculoskeletal tumours

PURPOSE

Pneumodissection is described as a simple method for preventing skin injury during cryoablation of superficial musculoskeletal tumours.

METHODS

Superficial tumour cryoablations performed from 2009 to 2015 were retrospectively reviewed. Pneumodissection was performed in 13 patients when the shortest tumour-skin distance was less than 25 mm. Indications were pain palliation (n = 9) and local tumour control (n = 4). Patients, target tumours, technical characteristics and complications up to 60 days post ablation were reviewed. The ice ball-skin distances with and without pneumodissection were compared by a paired t-test and further assessed for association with covariates using ANCOVA.

RESULTS

Technical success for ablation was 12 of 13. The mean shortest tumour-skin distance was 15.0 mm (3.2-24.5 mm). The mean thickness of pneumodissection was 9.6 mm (5.2-16.6 mm) resulting in mean elevation of skin of 3.4 mm (1.2-5.3 mm). Mean shortest ice ball-skin distance after pneumodissection was 10.5 mm (4.2-19.7 mm). No infection or systemic air embolism was noted. No intraprocedural frostbite was observed.

CONCLUSION

Pneumodissection is feasible, effective and safe in protecting the skin during image-guided cryoablation of superficial tumours.

KEY POINTS

• Frostbite during image-guided cryoablation of superficial tumours is commonly under-reported. • Frostbites are painful and may introduce infection into the superficial ablation zone. • Warm compress, saline and CO ₂ have shortcomings in protecting the skin. • Pneumodissection is free, readily available, easy to use and safe and effective.

Image-guided cryoablation for the treatment of painful musculoskeletal metastatic disease: a single-center experience

PURPOSE

The role of image-guided thermal ablation techniques for the nonoperative local management of painful osseous metastatic disease has expanded during recent years, and several advantages of cryoablation in this setting have emerged. The purpose of this study is to retrospectively evaluate and report a single-center experience of CT-guided percutaneous cryoablation in the setting of painful musculoskeletal metastatic disease.

METHODS

This study was approved by the institutional review board and is compliant with the Health Insurance Portability and Accountability Act. Electronic medical records of all patients who underwent percutaneous image-guided palliative cryoablation at our institution were reviewed (n = 61). An intent-to-treat analysis was performed. Records were reviewed for demographic data and anatomical data, primary tumor type, procedure details, and outcome-including change in analgesic requirements (expressed as morphine equivalent dosages), pain scores (utilizing the clinically implemented visual analog scale), subsequent therapies (including radiation and/or surgery), and complications during the 24 h following the procedure and at 3 months. Patients were excluded (n = 7) if data were not retrospectively identifiable at the defined time points.

RESULTS

Fifty-four tumors were ablated in 50 patients. There were statistically significant decreases in the median VAS score and narcotic usage at both 24 h and 3 months (p < 0.000). Six patients (11%) incurred complications related to their therapy. Two patients had no relief at 24 h, of which both reported worsened pain at 3 months. One patient had initial relief but symptom recurrence at 3 months. Four patients went on to have radiation therapy of the ablation site at some point following the procedure.

CONCLUSIONS

CT-guided cryoablation is a safe, effective, reproducible procedural option for the nonoperative local treatment of painful musculoskeletal metastatic disease.