Experimental cryosurgery investigations in vivo

Thermal Protection Techniques for Image-guided Musculoskeletal Ablation

Percutaneous image-guided thermal ablation has gained wide acceptance among physicians for the treatment of benign and malignant tumors of the musculoskeletal system. Increasing evidence to support the efficacy of thermal ablation techniques in primary and adjuvant treatment of soft-tissue sarcomas, treatment of oligometastatic disease to bone and soft tissue, and metastatic pain palliation has positioned interventional oncology alongside surgery, systemic therapies, and radiation therapy as the fourth pillar of modern comprehensive cancer care. Despite the expanding indications and increasing use in clinical practice, thermal ablation carries a significant risk of injury to the adjacent vulnerable structures, predominantly the skin, bowel, and neural structures. Knowledge of the mechanism of action of each thermal ablation modality informs the physician of the attendant risks associated with a particular modality. Thermal ablation mechanisms can be divided into hypothermic (cryoablation) and hyperthermic (radiofrequency ablation, microwave ablation, high-intensity focused US, or laser). Active thermal protection techniques include hydrodissection, pneumodissection, direct skin thermal protection, and physical displacement techniques. Passive thermal protection techniques include temperature monitoring, biofeedback, and neurophysiologic monitoring. The authors provide an overview of the mechanism of action of the most commonly used thermal ablation modalities, review the thermal injury risks associated with these modalities, and introduce the active and passive thermal protective techniques critical to safe and effective musculoskeletal ablative therapy. ©RSNA, 2025 See the invited commentary by Tomasian and Jennings in this issue.

Cryoballoon pulmonary vein isolation: Double stack vs standard ablation

BACKGROUND

The results of pulmonary vein isolation (PVI) are limited by arrhythmia recurrence, which is most often due to failure to effectuate a durable contiguous circumferential transmural lesion around the pulmonary vein ostia.

OBJECTIVE

We sought to determine if enhancing the index ablation line through the use of multiple cryoballoon diameters would be superior to standard ablation with bonus freeze.

METHODS

We enrolled 226 consecutive patients referred for cryoballoon-based PVI. Patients underwent PVI either with the 28-mm Arctic Front Advance (Medtronic, Minneapolis, Mn) cryoballoon using two 4-minute freezes (standard group) or with the POLARx FIT (Boston Scientific, Marlborough, Ma) cryoballoon using 3-minute freezes in both the 28- and 31-mm-diameter configurations (double stack group). Patients were followed for up to 1 year. The primary outcome was atrial tachyarrhythmia recurrence, with peri-procedural complications, cardioversion, emergency department visit, hospitalization, and repeat ablation being secondary outcomes.

RESULTS

A total of 226 patients were included (70% male; 47% with persistent atrial fibrillation [AF]). Patients in the double stack group had a significantly greater freedom from recurrent AF/atrial tachycardia/atrial flutter at 1 year (87.2% vs 68.9%; hazard ratio 0.41; 95% confidence interval 0.24-0.71; P=.008). Periprocedural complications were similar between the groups (5.2% vs 3.4%; P=.50). At 1 year, there was no difference in cardioversion (12.8% vs 20.3%; P=.20), emergency department visit (9.0% vs 15.5%; P=.22), or all-cause hospitalization (1.3% vs 2.7%; P=.66). Significantly less patients treated with double stack underwent repeat ablation (1.3% vs 13.5%; P=.002).

CONCLUSION

In a mixed cohort of patients with paroxysmal and persistent AF, cryoballoon ablation using the double stack technique is associated with lower rates of AF recurrence, aggregate healthcare utilisation, and lower rates of repeat ablation.

A novel technique of cryodenervation for murine vagus nerve: implications for acute lung inflammation

BACKGROUND

Neuroimmune interaction is an underestimated mechanism for lung diseases, and cryoablation is a competitive advantageous technique than other non-pharmacologic interventions for peripheral nerve innervating the lung. However, a lack of cryodenervation model in laboratory rodents leads to the obscure mechanisms for techniques used in clinic.

METHOD

Herein, we developed a novel practical method for mouse peripheral nerve cryoablation, named visualized and simple cryodenervation (VSCD). We first estimated the feasibility, safety and effectiveness of the technique via haematoxylin-eosin staining, histochemistry or immunofluorescence staining and immunoblotting assay. We then constructed the acute lung injury (ALI) model triggered by lipopolysaccharide (LPS) to verify the effect of VSCD in the resolution of pulmonary inflammation. Besides, the IL-10 knockout mice were also applied to explain the underlying mechanism of the protective activity of VSCD in ALI mice.

RESULT

We demonstrated that VSCD was able to induce a reliable and stable blockade of innervation, but reversible structural damage of mouse vagus nerve without detectable toxicity to lung tissues. Cholinergic parasympathetic nerve in the mouse lung coming from vagus nerve was activated at the initial stage (1 week) after VSCD, and blocked 3 weeks later. By use of the ALI mouse model, we found that VSCD effectively decreased pulmonary inflammation and tissue damage in the ALI mice. Moreover, the activated cholinergic anti-inflammatory pathway (CAP) and elevated IL-10 expression might explain the protective action of VSCD following LPS challenge.

CONCLUSION

This study fills the gap in the cryoablation for mouse vagus nerve, thereby guiding the application of cryodenervation in clinical management of pulmonary diseases. It also offers evidence of anti-inflammatory potential of VSCD in ALI mouse model and opens therapeutic avenues for the intervention of acute lung inflammation.

A Case Report of Cryoneurolysis With Factor VIII Administration for Cerebral Palsy-related Spasticity in a Patient With Hemophilia A

Spasticity affects up to 80% of individuals with cerebral palsy and can lead to pain and difficulties with performing activities of daily living. If left untreated, spasticity can progress to contracture and neuro-orthopedic deformities. Cryoneurolysis is an emerging and mini-invasive ultrasound-guided technique that causes secondary axonotmesis of peripheral nerves through the formation of an ice ball and may result in months to years of improved range of motion and reduced pain in patients with spasticity. However, the safety of cryoneurolysis has not yet been established in patients with an increased bleeding risk secondary to Hemophilia A. We present a case of cryoneurolysis for cerebral palsy-related spasticity in a 14-year-old male with hemophilia A who previously had minimal benefit from botulinum toxin for increased elbow and wrist flexor tone with contracture. Fifteen minutes prior to cryoneurolysis, an IV infusion of 2000 IU of recombinant antihemophilic factor (FVIII) was administered for bleeding prophylaxis. Targets were identified with ultrasound guidance and nerve stimulation and cryoneurolysis was performed without bleeding complications or adverse events. There was an immediate improvement in tone and range of motion that was maintained at 3- and 8-month follow-ups with reported increased left arm function. This case suggests that cryoneurolysis is an effective mini-invasive procedure for spasticity that improves tone and range of motion and is safe for use in patients with Hemophilia A who receive adequate Factor VIII prophylaxis.

Radiofrequency and Cryoablation as Energy Sources in the Cox-Maze Procedure: A Meta-Analysis of Rhythm Outcomes

AIM

Cox-maze IV is the most effective surgical procedure for atrial fibrillation (AF) treatment to date; however, few studies have compared the outcomes of the different energy sources applied to achieve transmurality. This study aimed to analyse the impact of the different energy sources on Cox-maze IV results in terms of sinus rhythm restoration.

METHOD

A systematic review and meta-analysis was conducted by including studies reporting rhythm outcomes on biatrial Cox-maze AF ablation with bipolar radio-frequency (BRF), cryoenergy (Cryo), or both (BRF+Cryo). The primary endpoints were the early and late rhythm outcomes of AF ablation using the different energy sources. Late AF recurrences were evaluated through timepoint analysis, and freedom from AF from Kaplan-derived data. Sixty articles including 8,293 patients were selected (3,364 patients Cryo, 1,937 BRF, and 2,992 BRF+Cryo).

RESULTS

At 6 months, AF incidence was significantly lower in the Cryo group at 6.73%; it was 25.52% in the BRF and 16.79% in the BRF+Cryo groups (p=0.0112). At the 4-year timepoint, AF incidence was lower in the Cryo group compared with the BRF and BRF+Cryo: 6.14% vs 51.59% vs 16.09%, respectively (p=0.0392). Freedom from AF was 76.7%±2.2%, 60.9%±2.2%, and 66.3%±1.6% for Cryo, BRF, and BRF+Cryo at 4 years, respectively (p<0.001). At meta-regression, mean left atrial diameter was positively associated with higher AF recurrences (OR 1.04, 95% CI 1.01-1.08; p=0.0159).

CONCLUSION

When performing this procedure, cryoablation seems to be associated with improved rhythm outcomes when compared with bipolar radiofrequency ablation.

Prospects of Synergy: Local Interventions and CAR T Cell Therapy in Solid Tumors

Chimeric antigen receptor T cell therapy has been established in the treatment of various B cell malignancies. However, translating this therapeutic effect to treat solid tumors has been challenging because of their inter-tumoral as well as intratumoral heterogeneity and immunosuppressive microenvironment. Local interventions, such as surgery, radiotherapy, local ablation, and locoregional drug delivery, can enhance chimeric antigen receptor T cell therapy in solid tumors by improving tumor infiltration and reducing systemic toxicities. Additionally, ablation and radiotherapy have proven to (re-)activate systemic immune responses via abscopal effects and reprogram the tumor microenvironment on a physical, cellular, and chemical level. This review highlights the potential synergy of the combined approaches to overcome barriers of chimeric antigen receptor T cell therapy and summarizes recent studies that may pave the way for new treatment regimens.

Tissue Ablation: Applications and Perspectives

Tissue ablation techniques have emerged as a critical component of modern medical practice and biomedical research, offering versatile solutions for treating various diseases and disorders. Percutaneous ablation is minimally invasive and offers numerous advantages over traditional surgery, such as shorter recovery times, reduced hospital stays, and decreased healthcare costs. Intra-procedural imaging during ablation also allows precise visualization of the treated tissue while minimizing injury to the surrounding normal tissues, reducing the risk of complications. Here, the mechanisms of tissue ablation and innovative energy delivery systems are explored, highlighting recent advancements that have reshaped the landscape of clinical practice. Current clinical challenges related to tissue ablation are also discussed, underlining unmet clinical needs for more advanced material-based approaches to improve the delivery of energy and pharmacology-based therapeutics.

CT-Guided Percutaneous Cryoablation of Breast Cancer: A Single-Center Experience

This study shall retrospectively evaluate the efficacy and safety of liquid-nitrogen based CT-guided cryoablation (CA) as a minimal-invasive technique for the curative treatment of primary breast cancer. A total of 45 female patients with 56 tumors were treated by CT-guided CA in analgosedation as an outpatient procedure. We used a liquid-nitrogen based system with a single cryoprobe and performed two freeze cycles with an intermediate thawing. The mean tumor diameter was 1.6 ± 0.7 cm. Follow-up was conducted via contrast-enhanced MR images of the breast. No complications were observed in all 56 ablations. Initial complete ablation was achieved in 100% of cases. Four cases of local tumor progression were reported, resulting in a rate of 8.9%, and 6 cases of intramammary distant recurrence at a rate of 13.3%. The extramammary tumor progression was observed in 7 patients at a rate of 15.6%. The mean overall survival was 4.13 years (95% CI: 3.7-4.5). The mean overall progression-free survival was 2.5 years (95% CI: 1.8-3.2) and the mean local progression-free survival was 2.9 years (95% CI: 2.3-3.6). Cryoablation is a safe and effective treatment for primary breast cancer tumors, which can be performed in analgosedation and as an outpatient procedure. However, potential for improvement exists and further evidence is necessary.

Optical Sensing of Tissue Freezing Depth by Sapphire Cryo-Applicator and Steady-State Diffuse Reflectance Analysis

This work describes a sapphire cryo-applicator with the ability to sense tissue freezing depth during cryosurgery by illumination of tissue and analyzing diffuse optical signals in a steady-state regime. The applicator was manufactured by the crystal growth technique and has several spatially resolved internal channels for accommodating optical fibers. The method of reconstructing freezing depth proposed in this work requires one illumination and two detection channels. The analysis of the detected intensities yields the estimation of the time evolution of the effective attenuation coefficient, which is compared with the theoretically calculated values obtained for a number of combinations of tissue parameters. The experimental test of the proposed applicator and approach for freezing depth reconstruction was performed using gelatin-based tissue phantom and rat liver tissue in vivo. It revealed the ability to estimate depth up to 8 mm. The in vivo study confirmed the feasibility of the applicator to sense the freezing depth of living tissues despite the possible diversity of their optical parameters. The results justify the potential of the described design of a sapphire instrument for cryosurgery.

Investigation of Lung Cancer Cell Response to Cryoablation and Adjunctive Gemcitabine-Based Cryo-Chemotherapy Using the A549 Cell Line

Due to the rising annual incidence of lung cancer (LC), new treatment strategies are needed. While various options exist, many, if not all, remain suboptimal. Several studies have shown cryoablation to be a promising approach. Yet, a lack of basic information pertaining to LC response to freezing and requirement for percutaneous access has limited clinical use. In this study, we investigated the A549 lung carcinoma cell line response to freezing. The data show that a single 5 min freeze to -15 °C did not affect cell viability, whereas -20 °C and -25 °C result in a significant reduction in viability 1 day post freeze to <10%. These populations, however, were able to recover in culture. Application of a repeat (double) freeze resulted in complete cell death at -25 °C. Studies investigating the impact of adjunctive gemcitabine (75 nM) pretreatment in combination with freezing were then conducted. Exposure to gemcitabine alone resulted in minimal cell death. The combination of gemcitabine pretreatment and a -20 °C single freeze as well as combination treatment with a -15 °C repeat freeze both resulted in complete cell death. This suggests that gemcitabine pretreatment may be synergistically effective when combined with freezing. Studies into the modes of cell death associated with the increased cell death revealed the increased involvement of necroptosis in combination treatment. In summary, these results suggest that repeat freezing to -20 °C to -25 °C results in a high degree of LC destruction. Further, the data suggest that the combination of gemcitabine pretreatment and freezing resulted in a shift of the minimum lethal temperature for LC from -25 °C to -15 °C. These findings, in combination with previous reports, suggest that cryoablation alone or in combination with chemotherapy may provide an improved path for the treatment of LC.

Cryoneurolysis for the Treatment of Knee Arthritis to Facilitate Inpatient Rehabilitation: A Case Report

A 65-year-old woman presenting with a sensory ganglionopathy complicated with COVID-19 is limited in her rehabilitation due to pain from lateral compartment knee osteoarthritis. To increase participation in rehabilitation, cryoneurolysis of the medial and lateral anterior femoral cutaneous nerve and infrapatellar branches of the saphenous nerve was provided to manage pain associated with knee osteoarthritis. The patient reported immediate relief from pain. Physiotherapy noted improvement immediately after the procedure. Follow-ups at 7- and 11-days post-treatment revealed ongoing increases in mobility and reduction in pain. The patient was discharged to live independently shortly after cryoneurolysis. Cryoneurolysis for knee osteoarthritis could be considered as a treatment option to increase participation in rehabilitation for hospital inpatients who are stalled in their rehabilitation due to pain and poor mobility from knee osteoarthritis.

Spasticity Treatment Beyond Botulinum Toxins

Botulinum toxin (BonT) is the mainstream treatment option for post-stroke spasticity. BoNT therapy may not be adequate in those with severe spasticity. There are a number of emerging treatment options for spasticity management. In this paper, we focus on innovative and revived treatment options that can be alternative or complementary to BoNT therapy, including phenol neurolysis, cryoneurolysis, and extracorporeal shock wave therapy.

Surgical options for atrial fibrillation treatment during concomitant cardiac procedures

Current guidelines recommend concomitant surgical ablation (SA) of atrial fibrillation (AF) in the context of mitral valve disease. A variety of energy sources have been tested for SA to perform effective transmural lesions reliably. To date, only radiofrequency and cryothermy energies are considered viable options. The gold standard for SA is the Cox-Maze ablation set, especially for non-paroxysmal AF (nPAF), with the aim of interrupting macro-reentrant drivers perpetuating AF, without hampering the sinus node activation of both atria, and to maintain the atrioventricular synchrony. Although the efficacy of SA in terms of early and late sinus rhythm restoration has been clearly demonstrated over the years, concomitant AF ablation is still underperformed in patients with AF undergoing cardiac surgery. From a surgical standpoint, concerns have been raised about whether a single (left) or double atriotomy would be justified in AF patients undergoing a "non-atriotomy" surgical procedure, such as aortic valve or revascularization surgery. Thus, an array of simplified lesion sets have been described in the last decade, which have unavoidably hampered procedural efficacy, somewhat jeopardizing the standardization process of ablation surgery. As a matter of fact, the term "Maze" has improperly become a generic term for SA. Surgical interventions that do not align with the principles of forming conduction-blocking lesions according to the Maze pattern, cannot be classified as Maze procedures. In this complex scenario, a tailored approach according to the different AF patterns has been proposed: for patients with concomitant nPAF, a biatrial Cox-Maze ablation is recommended. Conversely, it might be reasonable to limit lesions to the left atrium or the pulmonary veins in patients with paroxysmal AF (PAF) in some clinical scenarios. The aim of this review is to provide an overview of the current ablation strategies for patients with AF undergoing concomitant cardiac surgery.

The Assessment of a Novel Endoscopic Ultrasound-Compatible Cryocatheter to Ablate Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease that may be treated utilizing thermal therapies. Cryoablation is an effective, minimally invasive therapy that has been utilized for the treatment of various cancers, offering patients a quicker recovery and reduced side effects. Cryoablation has been utilized on a limited basis for the treatment of PDAC. With the recent reports on the success of cryoablation, there is a growing interest in the use of cryoablation as a standalone, minimally invasive procedure to treat PDAC. While offering a promising path, the application of cryoablation to PDAC is limited by current technologies. As such, there is a need for the development of new devices to support advanced treatment strategies for PDAC. To this end, this study investigated the performance of a new endoscopic ultrasound-compatible cryoablation catheter technology, FrostBite. We hypothesized that FrostBite would enable the rapid, effective, minimally invasive delivery of ultra-cold temperatures to target tissues, resulting in effective ablation via an endoscopic approach. Thermal properties and ablative efficacy were evaluated using a heat-loaded gel model, tissue-engineered models (TEMs), and an initial in vivo porcine study. Freeze protocols evaluated included single and repeat 3 and 5 min applications. Isotherm assessment revealed the generation of a 2.2 cm diameter frozen mass with the -20 °C isotherm reaching a diameter of 1.5 cm following a single 5 min freeze. TEM studies revealed the achievement of temperatures ≤ -20 °C at a diameter of 1.9 cm after a 5 min freeze. Fluorescent imaging conducted 24 h post-thaw demonstrated a uniformly shaped ellipsoidal ablative zone with a midline diameter of 2.5 cm, resulting in a total ablative volume of 6.9 cm3 after a single 5 min freeze. In vivo findings consistently demonstrated the generation of ablative areas measuring 2.03 cm × 3.2 cm. These studies demonstrate the potential of the FrostBite cryocatheter as an endoscopic ultrasound-based treatment option. The data suggest that FrostBite may provide for the rapid, effective, controllable freezing of cancerous pancreatic and liver tissues. This ablative power also offers the potential of improved safety margins via the minimally invasive nature of an endoscopic ultrasound-based approach or natural orifice transluminal endoscopic surgery (NOTES)-based approach. The results of this pre-clinical feasibility study show promise, affirming the need for further investigation into the potential of the FrostBite cryocatheter as an advanced, minimally invasive cryoablative technology.

Effect of cryothermic and radiofrequency Cox-Maze IV ablation on atrial size and function assessed by 2D and 3D echocardiography, a randomized trial. To freeze or to burn

BACKGROUND

Atrial linear scars in Cox-Maze IV procedures are achieved using Cryothermy (Cryo) or radiofrequency (RF) techniques. The subsequent postoperative left atrial (LA) reverse remodelling is unclear. We used 2- and 3-dimensional echocardiography (2-3DE) to compare the impact of Cryo and RF procedures on LA size and function 1 year after Cox-maze IV ablation concomitant with Mitral valve (MV) surgery.

METHODS

Seventy-two patients with MV disease and AF were randomized to Cryo (n = 35) or RF (n = 37) ablation. Another 33 patients were enroled without ablation (NoMaze). All patients underwent an echocardiogram the day before and 1 year after surgery. The LA function was assessed on 2D strain by speckle tracking and 3DE.

RESULTS

Forty-two ablated patients recovered sinus rhythm (SR) 1 year after surgery. They had comparable left and right systolic ventricular function, LA volume index (LAVI), and 2D reservoir strain before surgery. At follow-up, the 3DE extracted reservoir and booster function were higher after RF (37 ± 10% vs. 26 ± 6%; p < 0.001) than Cryo ablation (18 ± 9 vs. 7 ± 4%; p < 0.001), while passive conduit function was comparable between groups (24 ± 11 vs. 20 ± 8%; p = 0.17). The extent of LAVI reduction depended on the duration of AF preoperatively.

CONCLUSIONS

SR restoration after MV surgery and maze results in LA size reduction irrespective of the energy source used. Compared to RF, the extension of ablation area produced by Cryo implies a structural LA remodelling affecting LA systolic function.

Improvement in Nasal Symptoms of Chronic Rhinitis after Cryoablation of the Posterior Nasal Nerve

Objective

To determine the efficacy of posterior nasal nerve (PNN) cryoablation for improving the symptoms of chronic rhinitis.

Study Design

Retrospective cohort study.

Setting

A private practice.

Methods

This study evaluated medication usage and adverse effects of in-office PNN cryoablation with a handheld device in patients > 18 years with chronic (>6 months) allergic or nonallergic rhinitis for whom medical management failed. The total nasal symptom score (TNSS) and mini rhinoconjunctivitis quality of life questionnaire (mRQLQ) scores were compared before and after treatment.

Results

This study included 127 patients with a mean age of 52.4 ± 16.9 years; 60.6% of patients were female and 49.6% had allergic rhinitis. Mean symptom scores decreased from 5.94 (95% confidence interval [CI], 5.51-6.43) to 3.44 (95% CI, 2.97-3.81, P < .001) after the procedure, with clinically important decreases in 75 (59.1%) patients. For patients with baseline TNSS values of ≥4, 63.5% (66/104) had a clinically important decrease, whereas only 39.1% (9/23) of those with the lower baseline did (P = .04). Mean mRQLQ scores also decreased from 2.51 (95% CI, 2.29-2.72) to 1.28 (95% CI, 1.20-1.47, P < .001) after the procedure. Seventy-eight of 273 (28.6%) medications were discontinued after the procedure. Adverse effects occurred in 18.1% (23/127) of patients with headache as the most common.

Conclusion

PNN cryoablation improves nasal symptoms and quality of life in patients with chronic rhinitis. Patients with a higher baseline TNSS are more likely to experience significant symptomatic improvement.

Breast Cancer Cryoablation Fundamentals Past and Present: Technique Optimization and Imaging Pearls

Surgical treatment for breast cancer has evolved from radical mastectomy to modified radical mastectomy to breast-conserving surgery. As the de-escalation of surgical treatment for breast cancer continues, nonsurgical treatment for early-stage breast cancer with favorable ancillary features (low grade, positivity for hormone receptors) is being explored. Of the nonsurgical treatment options, cryoablation has demonstrated the greatest appeal, proven to be effective, safe, well tolerated, and feasible in an outpatient setting with local anesthetic alone. Results of past and interim results of current trials of cryoablation of stage I low-grade breast cancer with curative intent are promising, with an overall clinical success rate of 98% and recurrence rates consistent with those expected following lumpectomy. Cryoablation is also an alternative palliative treatment for patients who cannot tolerate or who have disease that is refractory to or recurs after standard-of-care breast cancer treatment and may have immunological therapeutic effects, warranting future research. Understanding the indications and optimal technique for breast cancer cryoablation and understanding typical imaging findings after cryoablation are essential to ensure the success of the procedure in carefully selected patients.

A Case Report of Cryoneurolysis for Dorsal Foot Pain and Toe Clawing in a Patient With Multiple Sclerosis

Toe clawing in patients with upper motor neuron disorders is often attributed to the flexor digitorum longus (FDL) and is a common presentation among patients with multiple sclerosis (MS). This movement may be painful because of the altered pressure distribution and may increase the risk of falls, heighten energy expenditure during gait, and lower gait speed. Cryoneurolysis is a minimally invasive treatment that may be beneficial for pain and focal muscle hypertonicity. An ambulatory patient with MS was treated bilaterally with cryoneurolysis to the superficial fibular nerves for pain on the dorsum of the foot, and to the intramuscular tibial nerve motor branch to FDL for toe clawing. The patient felt that toe clawing was immediately reduced during gait and noted the ability to voluntarily spread their toes. The patient stated that the neuropathic pain on the dorsum of the foot was fully eliminated immediately post procedure. The patient reported improved confidence in their gait, maintained independence, and reduced toe clawing during a structured interview 12 weeks after treatment. The effects lasted for 5.5 months before symptoms returned. Retreatment at 6 months reproduced the benefits. The patient reported a positive experience with cryoneurolysis for toe clawing and dorsal foot pain.

Comparison between cryoballoon double stop and single stop in patients with paroxysmal atrial fibrillation

BACKGROUND

Currently, cryoballoon (CB) thawing after single stop is generally performed. Previous research had reported that long thawing time using a single stop affects pulmonary veins tissue injury. However, it is uncertain whether CB thawing after single stop affects clinical outcomes.

OBJECTIVE

This study aimed to clarify clinical significance of CB thawing in patients with paroxysmal atrial fibrillation.

METHODS

Two hundred ten patients with paroxysmal atrial fibrillation who underwent CB from January 2018 to October 2019 were analyzed. We compared the clinical outcomes of patients whose CB applications were completely stopped with only the double stop technique (DS group, n = 99) and patients with single stop (SS group, n = 111). In DS group, we performed double stop technique for all CB application regardless of phrenic nerve injury or the temperature of esophagus.

RESULTS

The atrial arrhythmia free-survival rate at 2 years after CB was significantly lower for the DS group than the SS group (76.8% vs 87.4%; p = 0.045). Complications occurred in 2 patients from the DS group and no complications were observed in patients from the SS group (p = 0.13). Mean procedural time was shorter in the DS group than in the SS group (53.1 vs 58.1 min; p = 0.046) CONCLUSION: DS group had higher recurrence rate than SS group. There was no significant difference regarding safety between both the groups. We found that the thawing process after single stop is very important for CB application.

Intercostal nerve cryoablation during surgical stabilization of rib fractures decreases post-operative opioid use, ventilation days, and intensive care days

BACKGROUND

Intercostal nerve cryoablation is an adjunctive measure that has demonstrated pain control, decrease in opioid consumption, and decrease in hospital length of stay (LOS) in patients who undergo surgical stabilization of rib fractures (SSRF).

METHODS

SSRF patients from January 2015 to September 2021 were retrospectively compared. All patients received multimodal pain regimens post-operatively and the independent variable was intraoperative cryoablation.

RESULTS

241 patients met inclusion criteria. 51 (21%) underwent intra-operative cryoablation during SSRF and 191 (79%) did not. Patients with standard treatment consumed 9.4 more daily MME (p = 0.035), consumed 73 percent more post-operative total MME (p = 0.001), spent 1.55 times as many days in the intensive care unit (p = 0.013), and spent 3.8 times as many days on the ventilator than patients treated with cryoablation, respectively. Overall hospital LOS, operative case time, pulmonary complications, MME at discharge, and numeric pain scores at discharge were no different (all p>0.05).

CONCLUSION

Intercostal nerve cryoablation during SSRF is associated with fewer ventilator days, ICU LOS, total post-operative, and daily opioid use without increasing time in the operating room or perioperative pulmonary complications.

Cryoablation for the treatment of chronic rhinitis: a systematic review

BACKGROUND

ClariFix is a novel intranasal cryotherapy device developed for clinic-based cryosurgical ablation of the posterior nasal nerves region. As a relatively new technology, there is a paucity of studies within the literature assessing the efficacy and safety profile of ClariFix for chronic rhinitis.

METHODS

A systematic review was completed in accordance with PRISMA guidelines. Databases searched included: Ovid Medline, Ovid EMBASE, Pubmed, Cochrane and Web of Science. Inclusion criteria consisted of studies investigating the use of ClariFix in chronic rhinitis (i.e., allergic and non-allergic rhinitis) in patients of all ages.

RESULTS

The initial search identified 1110 studies. Final analysis consisted of 8 articles, evaluating a total of 472 patients. The data showed a significant reduction in scores post-treatment across all studies based on validated outcome measures. In all studies, at all time intervals, there was a significant improvement in outcome scores from baseline. Minor adverse effects included post-procedural pain and discomfort, headache and palate numbness. No major adverse events were identified.

CONCLUSION

ClariFix is a novel intranasal cryotherapy device that was introduced in Canada in 2021. This is the first systematic review evaluating its efficacy and safety profile. Across all studies, there was a significant reduction in validated outcome scores at multiple time intervals. Further, the treatment is safe with only minor adverse effects reported by patients. Overall, the consensus from this study highlights an apparent benefit in using this intervention for chronic rhinitis that is refractory to medical management.

Immunomodulatory effect of locoregional therapy in the tumor microenvironment

Cancer immunotherapy appears to be a promising treatment option; however, only a subset of patients with cancer responds favorably to treatment. Locoregional therapy initiates a local antitumor immune response by disrupting immunosuppressive components, releasing immunostimulatory damage-associated molecular patterns, recruiting immune effectors, and remodeling the tumor microenvironment. Many studies have shown that locoregional therapy can produce specific antitumor immunity alone; nevertheless, the effect is relatively weak and transient. Furthermore, increasing research efforts have explored the potential synergy between locoregional therapy and immunotherapy to enhance the long-term systemic antitumor immune effect and improve survival. Therefore, further research is needed into the immunomodulatory effects of locoregional therapy and immunotherapy to augment antitumor effects. This review article summarizes the key components of the tumor microenvironment, discusses the immunomodulatory role of locoregional therapy in the tumor microenvironment, and emphasizes the therapeutic potential of locoregional therapy in combination with immune checkpoint inhibitors.

Feasibility test of a sapphire cryoprobe with optical monitoring of tissue freezing

This article describes a sapphire cryoprobe as a promising solution to the significant problem of modern cryosurgery that is the monitoring of tissue freezing. This probe consists of a sapphire rod manufactured by the edge-defined film-fed growth technique from Al₂ O₃ melt and optical fibers accommodated inside the rod and connected to the source and the detector. The probe's design enables detection of spatially resolved diffuse reflected intensities of tissue optical response, which are used for the estimation of tissue freezing depth. The current type of the 12.5-mm diameter sapphire probe cooled down by the liquid nitrogen assumes a superficial cryoablation. The experimental test made by using a gelatin-intralipid tissue phantom shows the feasibility of such concept, revealing the capabilities of monitoring the freezing depth up to 10 mm by the particular instrumentation realization of the probe. This justifies a potential of sapphire-based instruments aided by optical diagnosis in modern cryosurgery.

Surgical Ablation of Cardiac Tissue with Nanosecond Pulsed Electric Fields in Swine

BACKGROUND

Myocardial tissue can be ablated by the application nanosecond pulsed fields (nsPEFs). The applied electric fields irreversibly permeabilize cell membranes and thereby kill myocytes while leaving the extracellular matrix intact.

METHODS

In domestic pigs (n = 10), hearts were exposed via sternotomy and either ablated in vivo ([Formula: see text] = 5) or in excised, Langendorff-perfused hearts ([Formula: see text] = 5). The nsPEFs consisted of 6-36 pulses of 300 ns each, delivered at 3-6 Hz; the voltage applied varied from 10 to 12 kV. Atrial lesions were either created after inserting the bottom jaw of the bipolar clamp into the atrium via a purse string incision (2-3 lesions per atrium) or by clamping a double layer of tissue at the appendages (one lesion per atrium). Ventricular lesions were created after an incision at the apex. The transmurality of each lesion was determined at three points along the lesion using a triphenyl tetrazolium chloride (TTC) stain.

RESULTS

All 27 atrial lesions were transmural. This includes 13/13 purse string lesions (39/39 sections, tissue thickness 2.5-4.5 mm) and 14/14 appendage lesions (42/42 sections, tissue thickness 8-12 mm). All 3 right ventricular lesions were transmural (9/9 sections, 18 pulses per lesion). Left ventricular lesions were always transmural for 36 pulses (3/3 lesions, 9/9 sections). All lesions have highly consistent width across the wall. There were no pulse-induced arrhythmias or other complications during the procedure.

CONCLUSIONS

nsPEF ablation reliably created acute lesions in porcine atrial and ventricular myocardium. It has far better penetration and is faster than both radiofrequency ablation and cryoablation and it is free from thermal side effects.

Salvage Percutaneous Cryoablation for Bleeding Upper Tract Urothelial Carcinoma

PURPOSE

Endoscopic access and treatment of bleeding upper urinary tract urothelial carcinomas (UTUCS) is sometimes difficult and inefficient as resection and/or laser coagulation are often incomplete. We report two cases of successful cryoablation of bleeding UTUCs.

MATERIALS AND METHODS

This study evaluated an adjunctive method in using cryoablation as a hemostatic technique. Cryoprobes were inserted inside the affected calices and a standard renal cryoablation protocol was used. Track ablation was performed during the pullback of the cryoprobes to prevent tumor seeding and bleeding.

RESULTS

Cryoablation of the bleeding upper urinary tract tumors allowed to efficiently resolve macrohematuria in both patients and to provide prolonged remission in one patient.

CONCLUSIONS

Taking advantage of the microcirculatory stasis and the hemostatic properties of cryoablation, we achieved palliative cessation of refractory macrohematuria while sparing nephrons, without the need for renal embolization in patients with bleeding UTUCs.

3D-Printed Biomaterial Testing in Response to Cryoablation: Implications for Surgical Ventricular Tachycardia Ablation

Background: The lack of thermally and mechanically performant biomaterials represents the major limit for 3D-printed surgical guides, aimed at facilitating complex surgery and ablations. Methods: Cryosurgery is a treatment for cardiac arrhythmias. It consists of obtaining cryolesions, by freezing the target tissue, resulting in selective and irreversible damage. MED625FLX and TPU95A are two biocompatible materials for surgical guides; however, there are no data on their response to cryoenergy delivery. The study purpose is to evaluate the biomaterials' thermal properties, examining the temperature changes on the porcine muscle samples (PMS) when the biomaterials are in place during the cryoablation. Two biomaterials were selected, MED625FLX and TPU95A, with two thicknesses (1.0 and 2.5 mm). To analyze the biomaterials' behavior, the PMS temperatures were measured during cryoablation, firstly without biomaterials (control) and after with the biomaterials in place. To verify the biomaterials' suitability, the temperatures under the biomaterial samples should not exceed a limit of -30.0 °C. Furthermore, the biomaterials' geometry after cryoablation was evaluated using the grid paper test. Results: TPU95A (1.0 and 2.5 mm) successfully passed all tests, making this material suitable for cryoablation treatment. MED625FLX of 1.0 mm did not retain its shape, losing its function according to the grid paper test. Further, MED625FLX of 2.5 mm is also suitable for use with a cryoenergy source. Conclusions: TPU95A (1.0 and 2.5 mm) and MED625FLX of 2.5 mm could be used in the design of surgical guides for cryoablation treatment, because of their mechanical, geometrical, and thermal properties. The positive results from the thermal tests on these materials and their thickness prompt further clinical investigation.

Research trends and areas of focus on cryoablation and oncology: A bibliometric analysis from 2001 to 2020

BACKGROUND

Cryoablation is an interdisciplinary, widely used treatment approach for several types of solid tumors, making it difficult to obtain a comprehensive picture of its current status and popular research topics. This study aimed to use a bibliometric approach to understand important research themes and trends in cryoablation and oncology.

METHODS

Literature studies on cryoablation and oncology from 2001 to 2020 were extracted from the Web of Science. A bibliometric analysis was performed based on the annual publication volume, several journal articles and local citation score, and distribution of keywords and trends in the literature using tools such as COOC version 9.94, VOSviewer version 1.6.17, and the bibliometrix version 3.1.3 R package.

RESULTS

This study included 2793 publications. Total yearly publications have plateaued over the last 20 years. Five research themes were presented in the keyword network, including clinical applications of cryoablation in liver, lung, kidney, prostate, and skin cancers and comparison of cryoablation with other energy ablations. After 2012, 2 new research topics emerged: synergy between cryoablation and immunotherapy in tumors and cryoablation of Barrett esophagus. The high cited literatures are dominated by studies related to cryoablation for renal and prostate cancer treatment, but they also reflect the recent increasing interest in immunotherapy and bone metastases. Twenty important journals were identified, with Cryobiology publishing the most articles.

CONCLUSION

Bibliometric analysis of studies related to tumor cryoablation can help researchers rapidly comprehend popular topics and determine future trends, guiding future research directions.

Effect of Prostate Volume and Minimum Tumor Temperature on 4-Year Quality-of-Life After Focal Cryoablation Compared with Active Surveillance in Men with Prostate Cancer

Background: The purpose of this study is to analyze quality-of-life (QoL) metrics in men treated with focal cryoablation (FC) compared with active surveillance (AS) for localized prostate cancer over a 4-year follow-up period. We further investigated the effect of prostate size and minimum tumor temperature on QoL outcomes. Methods: An Institutional Review Board-approved database was reviewed for patients who underwent FC or AS. QoL questionnaire responses were collected and scores were analyzed for differences between FC and AS, between prostate volume <50 cc and ≥50 cc, and "cold" (<-78°C) and "warm" (≥-78°C) tumor temperatures. Results: One hundred forty-eight AS and 60 FC patients were included. Compared with AS, no significant difference existed in urinary function (UF) measured by Expanded Prostate Cancer Index Composite (EPIC) (p = 0.593) and International Prostate Symptom Score (IPSS) (p = 0.241), bowel habits (p = 0.370), or anxiety (p = 0.672) across time post-FC. FC had significantly worse sexual function (SF) compared with AS measured by EPIC (p < 0.0001) and International Index of Erectile Function (IIEF) (p < 0.0001). Patients with prostate volume <50 cc did not demonstrate differences between AS and FC in UF on EPIC (p = 0.459) or IPSS (p = 0.628), but FC patients had worse SF on EPIC (p < 0.001) and IIEF (p < 0.001). FC patients with a prostate volume ≥50 cc had better UF measured by IPSS (p < 0.05) and similar SF on EPIC (p = 0.162) and IIEF (p = 0.771) compared with AS. UF over time measured by EPIC (0.825) and IPSS (p = 0.658) was the same between AS, "warm," and "cold" FC groups. AS had significantly better SF than the "warm" and "cold" FC groups on EPIC (p < 0.001) and IIEF (p < 0.05). Conclusions: No differences were found in anxiety, urinary, or bowel function between AS and FC. Despite differences in SF, patients with larger prostates had no difference in SF and improved UF compared with AS. Future studies with larger cohorts are needed.

Cytostatic hypothermia and its impact on glioblastoma and survival

Patients with glioblastoma (GBM) have limited options and require novel approaches to treatment. Here, we studied and deployed nonfreezing "cytostatic" hypothermia to stunt GBM growth. This growth-halting method contrasts with ablative, cryogenic hypothermia that kills both neoplastic and infiltrated healthy tissue. We investigated degrees of hypothermia in vitro and identified a cytostatic window of 20° to 25°C. For some lines, 18 hours/day of cytostatic hypothermia was sufficient to halt division in vitro. Next, we fabricated an experimental tool to test local cytostatic hypothermia in two rodent GBM models. Hypothermia more than doubled median survival, and all rats that successfully received cytostatic hypothermia survived their study period. Unlike targeted therapeutics that are successful in preclinical models but fail in clinical trials, cytostatic hypothermia leverages fundamental physics that influences biology broadly. It is a previously unexplored approach that could provide an additional option to patients with GBM by halting tumor growth.

Feasibility and Safety of Single-Probe Cryoablation with Liquid Nitrogen: An Initial Experience in 24 Various Tumor Lesions

Simple Summary

Percutaneous cryoablation was developed to minimally perform multi-organ tumor ablations. The most widely known cryotherapy systems use argon gas (high-pressure) and multiple needles to achieve sufficient ablations. The aim of our retrospective study was to assess the feasibility of a new cryotherapy system using single-probe liquid nitrogen for tumor lesions of various sizes and locations, and to evaluate the safety of cryoablation with this technique. Correlations between ice ball sizes and ablation zone sizes with two needle sizes (10G or 13G) and with the freezing duration were evaluated, as well as the sphericity of the ice ball and ablation zones. We showed that this technique is safe in all organs tested. We showed a correlation between the freezing duration and the ice ball size, but not with the ablation zone, which is useful for planning the procedure and treatment conducted by the oncology team.

Abstract

Background: Percutaneous cryoablation with liquid nitrogen is a new technique being used in the treatment of some malignant tumors. Our objective was to assess its feasibility in the ablation of tumor lesions of various sizes and locations. Methods: This retrospective, monocentric study included all consecutive patients who underwent percutaneous cryoablation with liquid nitrogen between December 2019 and March 2021. Cryoablation was performed using 10G or 13G cryoprobes. The ablation volume was measured on post-treatment CT or MRI. Results: 22 patients (24 lesions) were included, 16 of whom were men (73%), while median age was 66 years. The lesions were located in the bone (42%), kidney (29%), soft tissue (17%), lung (8%), or liver (4%). It was feasible in all tumor locations and produced median ablation zones 25 mm in width and 35 mm in length, with a 23 min median freezing time. Freezing duration was correlated with the ice volume (p Spearman = 0.02), but not with the ablation volume (p = 0.11). The average difference between the ablation zone and ice ball sizes were −6.4 mm in width and −7.7 mm in length. Both ice and ablation volumes were larger when using the 10G probe as compared to when the 13G was used. No complications were reported. Discussion: We showed that this technique was safe and feasible in all organs tested. The freezing duration was correlated with the ice ball size, but not with the ablation zone.

Efficacy of Gas Combination Cryotherapy in the Management of Odontogenic Keratocyst of the Maxilla and Mandible: A Pilot Study

Aim

The aim of this study was to evaluate outcome of management of odontogenic keratocyst (OKC) using gas combination cryotherapy (GCC). GCC is a treatment modality where cyst enucleation is followed by applying an adjuvant agent, a spray containing propane, butane and isobutene gas onto the bony bed.

Materials and Methods

This was a prospective interventional study which included patients with radiographic and histopathologic evidence of OKC. All patients underwent enucleation of the cysts followed by spraying of the bony cavity with "ENDOFROST ™"(commercially available agent for GCC). Patients were periodically reviewed and the presence of wound dehiscence, infection and neurosensory deficit was noted. After 15 months, a CBCT was taken to assess the amount of bone formation, the presence of any pathologic fracture or recurrence. Comparison of the preoperative and the postoperative size of the defect was also assessed.

Results

A total of 10 patients were included in the study of which only 2 presented with neurosensory deficit in the post-op period. One patient of the two patients recovered completely within 12 months, while the other recovered within 15 months. There was no evidence of any patient developing infection, wound dehiscence, recurrence or pathologic fracture.

Conclusion

The results of the study show that enucleation followed by GCC is a safe, effective and low-cost therapy for the management of OKC.

Non-Destructive Removal of Dental Implant by Using the Cryogenic Method

Background and Objectives: The gold standard for a successful prosthetic approach is the osseointegration of an implant. However, this integration can be a problem in cases where the implant needs to be removed. Removing the implant with minimal damage to the surrounding tissues is important. Osteocytes cannot survive below −2 °C, but epithelial cells, fibroblasts, and other surrounding tissue cells can. Remodeling can be triggered by cryotherapy at temperatures that specifically affect osteocyte necrosis. In this study, we aimed to develop a method for reversing the osseointegration mechanism and for protecting the surrounding tissues by bone remodeling induced by CO2 cryotherapy. Materials and Methods: In this study, eight 2.8 mm diameter, one-piece mini implants were used in New Zealand rabbit tibias. Two control and six implants were tested in this study. After 2 months of osseointegration, a reverse torque force method was used to remove all osseointegrated implants at 5, 10, 20, and 30 Ncm. The osseointegration of the implants was proven by periotest measurements. Changes in bone tissue were examined in histological sections stained with toluidine blue after rabbit sacrifice. The number of lacunae with osteocyte, empty lacunae, and lacunae greater than 5 µm and the osteon number in a 10,000 µm2 area were calculated. Cryotherapy was applied to the test implants for 1 min, 2 min, and 5 min. Three implants were subjected to cryotherapy at −40 °C, and the other implants were subjected to cryotherapy at −80 °C. Results: Empty lacunae, filled osteocytes, lacunae >5 µm, and the osteon count around the implant applied at −40 °C were not significantly different from the control implants. The application of −40 °C for 1 min was found to cause minimal damage to the bone cells. The implants, which were applied for 1 min and 2 min, were successfully explanted on the 2nd day with the 5 Ncm reverse torque method. Test implants, which were applied cold for 5 min, were explanted on day 1. Tissue damage was detected in all test groups at −80 °C. Conclusions: The method of removing implants with cryotherapy was found to be successful in −40 °C freeze−thaw cycles applied three times for 1 min. To prove implant removal with cryotherapy, more implant trials should be conducted.

Effect of pulmonary vein cryoballoon ablation in dogs with coolant-nitrogen

BACKGROUND

The Arctic Front Advance System with nitrous oxide (N2O) refrigerant is the leading system for the cryoballoon ablation of atrial fibrillation (AF). A novel cryoablation system with nitrogen (N2) refrigerant was developed with technical improvements seeking to improve outcomes. Cryoballoon ablation with the N2 refrigerant may be effective and safe for pulmonary vein isolation (PVI).

METHODS

In total, 16 dogs were included in the study, of which 13 underwent PVI procedures, and 3 served as baseline controls. Cryoballoons (Cryofocus, Int.) with N2 refrigerant were used for the study group, which comprised 8 dogs, and second-generation cryoballoons with N2O refrigerant (Arctic Front Advance; Medtronic, Inc., MN, USA) were used for the control group, which comprised 5 dogs. Three dogs of the study group and 2 dogs of the control group were euthanized on the same day post-ablation. The other 8 dogs of the two groups were euthanized 1 month post-ablation. The removed organs were examined for gross anatomy and histological review.

RESULTS

The average ablation times for each pulmonary vein (PV) in the study group were less than those in the control group (1.1±0.3 vs. 2.0±0.8; P=0.006). The procedure duration of the study group was shorter than that of the control group (379±46 vs. 592±162 s; P=0.013). And the time to isolation (TTI) was similar between the groups. The PVI rate of the single-ablation was higher in the study group than the control group (92.9% vs. 60.0%; P=0.05). In relation to safety, there was no evidence of thrombus, esophageal injury, or pericardial tamponade in any of the dogs. Only 1 incidence of self-limited phrenic nerve paralysis (PNP) was observed in the control group.

CONCLUSIONS

The novel cryoablation system with the N2 refrigerant had better efficacy than and similar safety to that of the system (Medtronic, Int.) with the N2O refrigerant.

CIRSE Standards of Practice on Thermal Ablation of Bone Tumours

Background

Percutaneous thermal ablation is an effective, minimally invasive means of treating a variety of focal benign and malignant osseous lesions. To determine the role of ablation in individual cases, multidisciplinary team (MDT) discussion is required to assess the suitability and feasibility of a thermal ablative approach, to select the most appropriate technique and to set the goals of treatment i.e. curative or palliative.

Purpose

This document will presume the indication for treatment is clear and approved by the MDT and will define the standards required for the performance of each modality. CIRSE Standards of Practice documents are not intended to impose a standard of clinical patient care, but recommend a reasonable approach to, and best practices for, the performance of thermal ablation of bone tumours.

Methods

The writing group was established by the CIRSE Standards of Practice Committee and consisted of five clinicians with internationally recognised expertise in thermal ablation of bone tumours. The writing group reviewed the existing literature on thermal ablation of bone tumours, performing a pragmatic evidence search using PubMed to search for publications in English and relating to human subjects from 2009 to 2019. Selected studies published in 2020 and 2021 during the course of writing these standards were subsequently included. The final recommendations were formulated through consensus.

Results

Recommendations were produced for the performance of thermal ablation of bone tumours taking into account the biologic behaviour of the tumour and the therapeutic intent of the procedure. Recommendations are provided based on lesion characteristics and thermal modality, for the use of tissue monitoring and protection, and for the appropriately timed application of adjunctive procedures such as osseus consolidation and transarterial embolisation.

Results

Percutaneous thermal ablation has an established role in the successful management of bone lesions, with both curative and palliative intent. This Standards of Practice document provides up-to-date recommendations for the safe performance of thermal ablation of bone tumours.

Cryoballoon ablation as salvage therapy after nonradical resection of a high-risk T1b esophageal adenocarcinoma: a case report

Although esophagectomy with or without (neo)adjuvant chemoradiation therapy is the current standard of care for patients with early esophageal adenocarcinoma with high-risk features or after nonradical endoscopic resection of an early esophageal adenocarcinoma, not all patients are eligible for surgery due to varying reasons. In these patients, cryoballoon ablation may serve as an alternative treatment option considering the potential of deeper tissue ablation as compared to heat-based ablation techniques. We report the first case in which cryoballoon ablation was successfully performed as salvage therapy with a curative intent for positive deep resection margins after an incomplete endoscopic resection of a recurrent early esophageal adenocarcinoma.

An In Vitro Investigation into Cryoablation and Adjunctive Cryoablation/Chemotherapy Combination Therapy for the Treatment of Pancreatic Cancer Using the PANC-1 Cell Line

As the incidence of pancreatic ductal adenocarcinoma (PDAC) continues to grow, so does the need for new strategies for treatment. One such area being evaluated is cryoablation. While promising, studies remain limited and questions surrounding basic dosing (minimal lethal temperature) coupled with technological issues associated with accessing PDAC tumors and tumor proximity to vasculature and bile ducts, among others, have limited the use of cryoablation. Additionally, as chemotherapy remains the first-line of attack for PDAC, there is limited information on the impact of combining freezing with chemotherapy. As such, this study investigated the in vitro response of a PDAC cell line to freezing, chemotherapy, and the combination of chemotherapy pre-treatment and freezing. PANC-1 cells and PANC-1 tumor models were exposed to cryoablation (freezing insult) and compared to non-frozen controls. Additionally, PANC-1 cells were exposed to varying sub-clinical doses of gemcitabine or oxaliplatin alone and in combination with freezing. The results show that freezing to −10 °C did not affect viability, whereas −15 °C and −20 °C resulted in a reduction in 1 day post-freeze viability to 85% and 20%, respectively, though both recovered to controls by day 7. A complete cell loss was found following a single freeze below −25 °C. The combination of 100 nM gemcitabine (1.1 mg/m2) pre-treatment and a single freeze at −15 °C resulted in near-complete cell death (<5% survival) over the 7-day assessment interval. The combination of 8.8 µM oxaliplatin (130 mg/m2) pre-treatment and a single −15 °C freeze resulted in a similar trend of increased PANC-1 cell death. In summary, these in vitro results suggest that freezing alone to temperatures in the range of −25 °C results in a high degree of PDAC destruction. Further, the data support a potential combinatorial chemo/cryo-therapeutic strategy for the treatment of PDAC. These results suggest that a reduction in chemotherapeutic dose may be possible when offered in combination with freezing for the treatment of PDAC.

Endoscopic cryotherapy: Indications, techniques, and outcomes involving the gastrointestinal tract

Endoscopic cryotherapy is a technique utilized for the ablation of target tissue within the gastrointestinal tract. A cryotherapy system utilizes the endoscopic application of cryogen such as liquid nitrogen, carbon dioxide or liquid nitrous oxide. This leads to disruption of cell membranes, apoptosis, and thrombosis of local blood vessels within the target tissue. Several trials utilizing cryotherapy for Barrett's esophagus (BE) with variable dysplasia, gastric antral vascular ectasia (GAVE), esophageal carcinoma, radiation proctitis, and metastatic esophageal carcinomas have shown safety and efficacy. More recently, liquid nitrogen cryotherapy (cryodilation) was shown to be safe and effective for the treatment of a benign esophageal stricture which was refractory to dilations, steroid injections, and stenting. Moreover, liquid nitrogen cryotherapy is associated with less post procedure pain as compared to radiofrequency ablation in BE with comparable ablation rates. In patients with GAVE, cryotherapy was found to be less tedious as compared to argon plasma coagulation. Adverse events from cryotherapy most commonly include chest pain, esophageal strictures, and bleeding. Gastric perforations did occur as well, but less often. In summary, endoscopic cryotherapy is a promising and growing field, which was first demonstrated in BE, but the use now spans for several other disease processes. Larger randomized controlled trials are needed before its role can be established for these different diseases.

Five-Year Outcomes of Concomitant Maze Procedure Using Nitrous Oxide versus Argon-Based Cryoablation

BACKGROUND

Cryoablation is effective for ablating the myocardium but maintaining the structure of the ablated tissue. However, data comparing nitrous oxide (N₂O)-based and argon gas-based cryoprobes are limited.

METHODS

This study was a follow-up study of a single-center, prospective, randomized controlled trial in which 60 patients were randomly allocated to either the N₂O group or the argon group. The primary endpoint of this study was sinus rhythm maintenance, and the key secondary endpoint was a composite of major adverse cardiovascular and cerebrovascular events (MACCEs) (i.e., cardiac death, stroke, major bleeding, and readmission for heart failure).

RESULTS

The baseline and operative characteristics of the patients in the N₂O and argon groups were comparable. At the 5-year follow-up, the rate of sinus rhythm maintenance was 81.8% in the N₂O group, whereas it was 78.5% in the argon group (p > 0.999). No significant differences in the rate of freedom from MACCEs (80.6% in the N₂O group vs. 81.9% in the argon group; P = .978) was observed at the 5-year follow-up. The left atrial volume index decreased over time from 114.65 mL/m² to 65.74 mL/m² (P < .0001) and reached similar values in the two groups (P = .279) at the 5-year follow-up.

CONCLUSIONS

Both N₂O- and argon gas-based cryoprobes showed similar rates of sinus rhythm maintenance and freedom from MACCEs at the 5-year follow-up. Both cryoprobes might have similar efficacy and safety in the arrested heart in the long term.

Current advances in immune checkpoint inhibitor combinations with radiation therapy or cryotherapy for breast cancer

PURPOSE

Immune checkpoint inhibition (ICI) has demonstrated clinically significant efficacy when combined with chemotherapy in triple negative breast cancer (TNBC). Although many patients derived benefit, others do not respond to immunotherapy, therefore relying upon innovative combinations to enhance response. Local therapies such as radiation therapy (RT) and cryotherapy are immunogenic and potentially optimize responses to immunotherapy. Strategies combining these therapies and ICI are actively under investigation. This review will describe the rationale for combining ICI with targeted local therapies in breast cancer.

METHODS

A literature search was performed to identify pre-clinical and clinical studies assessing ICI combined with RT or cryotherapy published as of August 2021 using PubMed and ClinicalTrials.gov.

RESULTS

Published studies of ICI with RT and IPI have demonstrated safety and signals of early efficacy.

CONCLUSION

RT and cryotherapy are local therapies that can be integrated safely with ICI and has shown promise in early trials. Randomized phase II studies testing both of these approaches, such as P-RAD (NCT04443348) and ipilimumab/nivolumab/cryoablation for TNBC (NCT03546686) are current enrolling. The results of these studies are paramount as they will provide long term data on the safety and efficacy of these regimens.

Rationale and Outcomes of Cryoballoon Ablation of the Left Atrial Posterior Wall in Conjunction with Pulmonary Vein Isolation

There is strong evidence in support of pulmonary vein isolation (PVI) with concomitant left atrial (LA) posterior wall (PW) isolation (PWI) for the treatment of patients with persistent atrial fibrillation (persAF). While this may be achieved using surgical and catheter-based strategies, there is growing interest in performing this approach using the cryoballoon. There are several potential advantages to this strategy. First, lesions created using the current-generation cryoballoons are typically large and durable. Second, cryoballoon ablation offers a simple technique to directly ablate and debulk the LAPW. Moreover, some consider cryoenergy a safer modality specifically with regard to collateral structures (ie, the esophagus). Based on the available data, cryoballoon PVI + PWI is associated with greater intraprocedural AF terminations and reductions in long-term AF recurrence (typically by ~20%), as compared to PVI alone in patients with persAF, but with similar rates of adverse events. As such, PVI + PWI has emerged as a significant predictor of freedom from recurrent AF (odds ratio: 3.67, 95% confidence interval: 1.44-9.34; p = 0.006) as well as all atrial arrhythmias (hazard ratio: 2.04, 95% confidence interval: 1.15-3.61; p = 0.015). Adjunct radiofrequency ablation to complete PWI is required in at least one-third of the patients, and this need is highly predicted by the LA size (significantly increased with an LA diameter > 48 mm). LAPW reconnection also seems to be associated with LA dimension, particularly an LA diameter greater than 48 mm (negative predictive value: 89.7%). Nevertheless, based on the analysis of patients who underwent repeat electrophysiology study for arrhythmia recurrences, cryoballoon PVI + PWI yields acceptable long-term durability (> 80%).

Management of the Cavity After Removal of Giant Cell Tumor of the Bone

Purpose: To find out the most appropriate management scheme through the analysis and comparison of different inactivation methods and filling materials. Method: A systematic literature search was performed using the terms, anhydrous ethanol, phenol, hypertonic saline, cryotherapy, thermal therapy, bone reconstruction, GCTB, and etc., Selected articles were studied and summarized. The mechanism, clinical effects, and influence on bone repair of various methods are presented. Recent developments and perspectives are also demonstrated. Recent Findings: Compared to curettage alone, management of the residual cavity can effectively reduce the recurrence of giant cell tumours of bone. It is a complex and multidisciplinary process that includes three steps: local control, cavity filling, and osteogenic induction. In terms of local control, High-speed burring can enlarge the area of curettage but may cause the spread and planting of tumour tissues. Among the inactivation methods, Anhydrous ethanol, and hyperthermia therapy are relatively safe and efficient. The combination of the two may achieve a better inactivation effect. When inactivating the cavity, we need to adjust the approach according to the invasion of the tumour. Filling materials and bone repair should also be considered in management.

Cryosurgery for Atrial Fibrillation: Physiologic Basis for Creating Optimal Cryolesions

BACKGROUND

Although cryosurgery has been used to treat cardiac arrhythmias for nearly 5 decades, the mechanism of action and the surgical technique that produces optimal cryolesions for the treatment of atrial fibrillation are still poorly understood. This has resulted in surgical outcomes that can be improved by a better understanding the mechanisms of cryothermia ablation and the proper surgical techniques that take advantage of those mechanisms.

METHODS

The cryobiology underlying cryosurgical ablation is described, as are the nuances of cryosurgical techniques that ensure the reliable creation of contiguous, uniformly transmural atrial cryolesions. The oft-misunderstood "2-minute rule" for the application of cryothermia is clarified in detail, along with its variations that depend on target myocardial temperature.

RESULTS

The creation of optimal cryolesions depends on cryoprobe temperature, the temperature of the target myocardium, the duration of cryothermia application, and the presence or absence of a "heat sink" or "cooling sink" created by intracavitary blood circulation. Cryothermia kills myocardial cells during both the freezing and thawing phases of cryoablation cycle. The critical lethal temperature for myocardium is -30°C. The slower the target tissue thaws, the higher the percentage of cell death.

CONCLUSIONS

The availability of cryosurgical techniques has revolutionized the surgical treatment of atrial fibrillation. By utilizing modern cryosurgical devices and adhering to the technical principles described, surgeons can now perform surgical procedures for atrial fibrillation that are quicker, safer, and as effective as the standard Maze-III/IV procedure.

Segmental nonocclusive cryoballoon ablation of pulmonary veins and extrapulmonary vein structures: Best practices III

Although cryoballoon ablation of atrial fibrillation (AF) traditionally has been guided by pulmonary vein (PV) occlusion, there is evidence and growing interest in performing segmental, nonocclusive cryoballoon ablation to target not only large/common PVs but extra-PV structures such as the left atrial (LA) roof and posterior wall in conjunction with PV isolation. A number of studies have demonstrated improved clinical efficacy associated with nonocclusive cryoballoon ablation of the LA roof and posterior wall in addition to PV isolation, particularly in patients with persistent AF. Not only can the cryoballoon be used for targeting extra-PV structures through segmental, nonocclusive ablation, but the large size and durability of cryolesions coupled with the enhanced stability afforded through cryoadhesion render the cryoballoon an effective tool for such an approach. This article reviews the rationale and practical approach to segmental, nonocclusive cryoballoon ablation of large/common PV antra and the LA roof and posterior wall.

Image-guided Cryotherapy for Musculoskeletal Tumors

BACKGROUND

This article represents a review of the use of image-guided cryotherapy in the treatment of musculoskeletal tumor lesions. Cryotherapy is able to induce a lethal effect on cancer cells through direct and indirect mechanisms. In this manuscript, we combined our experience with that of other authors who have published on this topic in order to provide indications on when to use cryotherapy in musculoskeletal oncology.

DISCUSSION

Image-Guided percutaneous cryotherapy is a therapeutic method now widely accepted in the treatment of patients with musculoskeletal tumors. It can be used both for palliative treatments of metastatic bone lesions and for the curative treatment of benign bone tumors, such as osteoid osteoma or osteoblastoma. In the treatment of bone metastases, cryotherapy plays a major role in alleviating or resolving disease-related pain, but it has also been demonstrated that it can have a role in local disease control. In recent years, the use of cryotherapy has also expanded for the treatment of both benign and malignant soft tissue tumors.

CONCLUSION

Percutaneous cryotherapy can be considered a safe and effective technique in the treatment of benign and malignant musculoskeletal tumors. Cryotherapy can be considered the first option in benign tumor lesions, such as osteoid osteoma, and a valid alternative to radiofrequency ablation. In the treatment of painful bone metastases, it must be considered secondarily to other standard treatments (radiotherapy, bisphosphonate therapy, and chemotherapy) when they are no longer effective in controlling the disease or when they cannot be repeated (for example, radiotherapy).

Acute Safety and Efficacy of Fluoroless Cryoballoon Ablation for Atrial Fibrillation

Pulmonary vein isolation (PVI) is widely used for the ablation of atrial fibrillation, with prior reports suggesting good efficacy. Due to the widespread use of three-dimensional electroanatomic mapping systems and advances in intracardiac echocardiography, fluoroless ablation has been made possible. Fluoroless ablation with a cryoballoon (CB), however, has not been widely performed because of the need to prove occlusion of the vein with contrast dye and fluoroscopy. The objective of this study is to show that CB ablation can be performed safely and effectively without fluoroscopy. A dual-center, case–control study was performed of patients undergoing CB PVI with a fluoroless approach and a control group with traditional fluoroscopic techniques. The absence of color-flow Doppler signals around the periphery of the CB on intracardiac echocardiography and an increase in mean pressure by 5 mmHg, loss of the A-wave, and an increase in the V-wave as measured with continuous-wave pressure monitoring were adopted as indicators of vein occlusion in the absence of fluoroscopy. Temperature at 30 seconds, minimum temperature, time to isolation, procedure length, and complications were evaluated. During the study period of November 15, 2018 to November 15, 2019, a total of 100 patients underwent CB PVI at the participating centers. A total of 50 patients were enrolled in the fluoroless arm [35 men (70%), mean age: 64.9 ± 12 years, mean left atrium size: 44.2 ± 16 mL/m², left ventricular ejection fraction: 61% ± 5%], while 50 patients were enrolled in the control arm with similar characteristics. Four hundred forty-one 441 PVs were evaluated in the study cohort compared to 339 PVs in the control arm. When comparing fluoroless and traditional techniques, the mean temperature at 30 seconds was −31.7°C ± 6°C versus −32.8°C ± 5°C (p = 0.037), the minimum temperature was −47.4°C ± 6°C versus −47.7°C ± 9°C (p = 0.677), the time to isolation was 56.8 ± 28 seconds versus 74.8 ± 45 seconds (p = 0.212), and the procedure time was 102.2 ± 27.3 seconds versus 104.5 ± 16.9 seconds (p = 0.6436). Ultimately, this proof-of-concept study revealed that fluoroless ablation can be performed with success and efficiency outcomes similar to those of a traditional ablation approach. This suggests that the ablation of atrial fibrillation with CB can be performed safely and effectively without the use of fluoroscopy by experienced operators.

Percutaneous Cryoablation of Multiple Pulmonary Endometriosis

Minimally invasive cryoablation is often considered for lung tumor patients with high surgical risk or inoperable metastatic lung tumors. Cryoablation is a type of thermal percutaneous ablation in which argon and helium gases are delivered via a cryoprobe to induce tissue freezing and necrosis. We report the case of a 23-year-old woman who had suffered from multiple pulmonary endometriosis with frequent intermittent hemoptysis during menstruation for 6 years prior to her visit. She was treated with cryoablation at our hospital, and since her treatment, she has been doing well with no hemoptysis for at least 6 months. Although endometriosis is a benign lung disease, cryoablation is an ideal and effective treatment option for patients with multiple endometriosis.

A Novel, Efficient, Unit Circle-Based, Method for Positioning and Operating Cryo-Surgical Probes in Convex Target Areas

A novel method for positioning and operating needle-like cryo-surgical probes in 2D convex target areas is presented. The method is based on the recorded dynamic performance of a single probe, termed "unit circle," (UC) embedded in a semi-infinite, tissue-like medium. Up to 15 cryo-probes, inserted into the same depth, are operated uniformly for 2-5 min. A predetermined number of probes are rearranged inside the target area until a "tight configuration" is obtained. The probes are initially arranged inside the target area such that the "lethal temperature" circles produced by them are tangent to its contour and to both adjacent lethal temperature circles. Subsequently, all probes are repositioned inwardly, each at a specific distance that depends on the local radius of curvature of the target area. Resulting total "defect areas"-internal and external-for a number of demonstrated cases, amounted to between 2.5% and 7.6% of the target area. The lower values of the defect areas were obtained with increasing numbers of inserted probes coupled with shorter operating times. Possible freezing damages to regions beyond the target area were reduced by up to about 30% for these cases. Similar results were obtained for a case of combined convex-concave target area, treated with additional, externally inserted, heating probes.

Updates in Cryotherapy for Barrett's Esophagus

Cryotherapy is an ablation modality relying on freeze-thaw cycles to promote cell death through intracellular ice crystal formation, ischemia, and apoptosis. Currently, 2 different cryotherapy systems are available for esophageal use. The first is cryospray ablation, which involves repetitive applications of liquid nitrogen. The second system, cryoballoon ablation, freezes the esophageal mucosa with liquid nitrous oxide using a compliant balloon. To date, studies have shown that cryotherapy is an effective and safe method for eradicating Barrett's esophagus; however, larger prospective series with longer follow-up are warranted to determine the clinical utility of cryotherapy in the treatment of Barrett's esophagus.