Real-Time Internal Steam Pop Detection during Radiofrequency Ablation with a Radiofrequency Ablation Needle Integrated with a Temperature and Pressure Sensor: Preclinical and Clinical Pilot Tests

A radiofrequency ablation (RFA) needle integrated with a temperature sensor (T-sensor) and pressure sensor (P-sensor) is designed and utilized for real-time internal steam pop monitoring during RFA. The characteristics of the sensor-integrated RFA needle (sRFA-needle) are investigated quantitatively using a pressure chamber system, and the feasibility and usability of the needle in preclinical and clinical trials is demonstrated. The sharp changes in the temperature and normalized pressure sensor signals induced by the abrupt release of hot and high-pressure steam can be clearly monitored during the steam pop phenomena. The basic mechanism of the preliminary steam pop is hypothesized and verified using in situ ultrasound imaging data and computational analysis data of the RFA procedure. Moreover, the usability of the system in clinical trials is investigated, and the steam pop phenomena during the RFA procedure are detected using T-sensor and P-sensor. The results confirm that the sensor integration on the medical needle can provide critical data for safer and more effective medical practices.

The safety of bipolar mode radiofrequency (BMRF) on cochlear implant integrity test; a clinical prospective study

PURPOSE

We aimed to assess the effect of bipolar mode radiofrequency (BMRF) tonsillectomy as a model of oro-pharyngeal surgical maneuver on the integrity of the internal device in patients with cochlear implants (CIs).

MATERIALS AND METHODS

This prospective case series included 15 consecutive pediatric patients with CIs (age range 4 to 8 years, mean 5.2 years) who underwent BMRF tonsillectomy. The postoperative integrity of the internal device was evaluated by comparing the electric current response tested preoperatively with that tested 2 days postoperatively.

RESULTS

There were differences in the current levels in the main regions of the cochlea; (the apical, mid-turn, and basal) after comparing preoperative and postoperative values, but they were not statically significant.

CONCLUSION

BMRF seems to be safe for tonsillectomy in children with CIs without negative impact on the integrity of the internal device.

Radiofrequency combined with immunomodulation for hepatocellular carcinoma: State of the art and innovations

Hepatocellular carcinoma (HCC) is the most common primary liver tumor and has been considered a very immunogenic tumor. The treatment with radiofrequency ablation (RFA) has been established as the standard ablative therapy for early HCC, and is currently recognized as the main ablative tool for HCC tumors < 5 cm in size; however, progression and local recurrence remain the main disadvantages of this approach. To solve this clinical problem, recent efforts were concentrated on multimodal treatment, combining different strategies, including the combination of RFA and immunotherapy. This article reviewed the combination treatment of RFA with immunotherapy and found that this treatment strategy leads to an increased response of anti-tumor T cells, significantly reduces the risk of recurrence and improves survival rates compared to RFA alone. This review highlighted scientific evidence that supports the current recommendations for pre-clinical studies, and discuss the need for further research on this topic.

Large nearly spherical ablation zones are achieved with simultaneous multi-antenna microwave ablation applied to treat liver tumours

AIM

To investigate the shape and the volume of ablation zones obtained with microwave ablation (MWA) performed with multiple antennas in liver tumours.

MATERIALS AND METHODS

Tumour volume, number of antennas, size (long diameter (Dl), along the antenna axis; short diameter (Ds), perpendicular to the antenna axis; vertical diameter (Dv), vertical to both Dl and Ds) and shape (roundness index (RI); 1 corresponds to a sphere) of the ablation zone, ablation volume, and complications were evaluated.

RESULTS

Mean Dl, Ds, and Dv were 4.7 ± 1.4 cm, 3.9 ± 1.4 cm, and 3.8 ± 1.0 cm, respectively. Mean RIs (Ds/Dl, Dv/Dl, and Dv/Ds) were 0.83 ± 0.13, 0.83 ± 0.17, and 1.02 ± 0.23, respectively, without any difference between the mean RI obtained with the double (0.84 ± 0.01) and that with the triple-antenna (0.93 ± 0.13) approach (p = 0.25). Mean ablation volume was 41 ± 32 cm³ (vs. mean tumour volume 13 ± 10 cm³; range 1-40; p < 0.001). No complications were noted.

CONCLUSIONS

Simultaneous multi-antenna MWA of liver tumours results in large nearly spherical ablation zones.

KEY POINTS

• Simultaneous multi-antenna microwave ablation of liver tumours results in nearly spherical ablation zones. • The multi-antenna approach generates oversized ablation volumes compared with the target tumour volume. • The multi-antenna approach is safe.

Estimating the Incidence of Stray Energy Burns during Laparoscopic Surgery based on Two Statewide Databases and Retrospective Rates: An Opportunity to Improve Patient Safety

BACKGROUND

The growth of laparoscopic surgery has increased the use of laparoscopic electrosurgical devices based on radiofrequency current. Despite an improvement in most post-operative outcomes, the use of these devices can be associated with inadvertent thermal or mechanical injuries, also called accidental punctures and lacerations (APLs). APLs can occur through either operator error or system error, including insulation failure or capacitive coupling resulting in stray energy burns. Our aim was to estimate the incidence and-as a result-the impact of laparoscopic APLs.

METHODS

A retrospective analysis of the Healthcare Cost and Utilization Project (HCUP) State Inpatient Database (SID) was performed for 2009 in California (CA) and Florida (FL). ICD-9 codes and current procedural terminology were used to query for five common general surgery procedures: appendectomy, cholecystectomy, fundoplication, gastric bypass, and gastroplasty with these procedures cross-referenced for any secondary procedure at the time of the initial surgery indicative of APLs. The c2 test was used for comparisons where appropriate.

RESULTS

Overall, 192,794 primary laparoscopic procedures were identified in the HCUP database in CA and FL in 2009, with a similar procedure frequency distribution between CA and FL. Six hundred ninety-four procedures were complicated by APL. Gastric bypass and fundoplication were more commonly associated with APLs.

CONCLUSION

In this retrospective analysis of procedures performed in CA and FL, the estimated incidence of APL was 3.6 per 1000 cases. Patient morbidity and mortality were likely related to both pilot-error injuries and stray energy burns during laparoscopy. Possible solutions to reduce surgical complications from APL include educational programs to reduce pilot error and the incorporation of fail-safe technologies to eliminate stray energy burns, such as active electrode monitoring and use of non-radiofrequency current (true cautery).

A New RF Heating Strategy for Thermal Treatment of Atherosclerosis

OBJECTIVES

Restenosis remains a challenge for the treatment of atherosclerosis due to the damage of the endothelial layer and induced proliferation of the smooth muscle cell.

METHODS

A new RF heating strategy was proposed to selectively ablate the atherosclerosis plaque, and to thermally inhibit the proliferation of smooth muscle cells, while keeping the endothelial cells intact. To achieve the goal, an internal cooling agent and distributed electrodes have been integrated in the new designed balloon catheter to focus the shape conformal energy onto the plaque shape. A three-dimensional (3-D) model with experimentally fitted parameters has been established to demonstrate the heating ability of the design and evaluate the microelectrodes configurations for different plaque geometries.

RESULTS

The 3-D shape of the lesions resulting from different electrodes settings is obtained. It is found that by individual control of the micro-electrodes, special shapes of the lesions can be formed, which can match the eccentric crescent plaques. Besides, through changing of the polarity of the electrodes, separate lesions can be reached. This suggests the possibility for treatment of disconnected plaques in situ.

CONCLUSION

By the control of RF heating and convection coefficient of the internal cooling agent, a targeted heating region away from the inner surface of the blood vessel can be realized.

SIGNIFICANCE

This study has illustrated the possibility of achieving a precision thermal treatment of atherosclerosis in favor of inhibiting further restenosis.

Transanal repair of rectocele with high frequency radio scalpel

AIM

This is a prospective randomized study to analyze results obtained in two groups of patients, affected by stage 2 rectocele and treated with rectum anterior wall repair and strength, performed with standard or modified Khubchandani technique, using High Frequency (HF) Radio Scalpel.

MATERIALS AND METHODS

A cohort of 24 patients with stage 2 rectocele (Mellgren's classification) have been included. Twelve (group A) underwent surgery with standard technique and twelve (group B) underwent surgery using the HF Radio Scalpel, which cuts and coagulates tissues without damage thanks to its low working temperature (45-70°C). Each patient underwent proctolo-gical examination and anoscopy in 7th, 15th, 45th POD and after 6 and 12 months.

RESULTS

During post-operative follow-up 5 patients from group A and 1 from group B didn't show up so that they drop out the study. As a result, group A is composed by 7 patients and group B by 11 patients. Mean operating time was significantly favourable in group B (51 vs 33 minutes, p< 0.01). The differences between other parameters weren't statistically significant, even if post-operative course was less difficult in HF Radio Scalpel group.

CONCLUSIONS

The surgical technique to repair and reinforce anterior rectal wall is easier and faster if performed with HF Radio Scalpel respect to the standard procedure described by Khubchandani. Post-operative course was less painful and, even more importantly considering the patient age, surgical time was shorter. Therefore, the results obtained cast positive light on using this technique to treat uncomplicated grade 2 rectocele.

Higher contact force during radiofrequency ablation leads to a much larger increase in edema as compared to chronic lesion size

INTRODUCTION

Reversible edema is a part of any radiofrequency ablation but its relationship with contact force is unknown. The goal of this study was to characterize through histology and MRI, acute and chronic ablation lesions and reversible edema with contact force.

METHODS AND RESULTS

In a canine model (n = 14), chronic ventricular lesions were created with a 3.5-mm tip ThermoCool SmartTouch (Biosense Webster) catheter at 25 W or 40 W for 30 seconds. Repeat ablation was performed after 3 months to create a second set of lesions (acute). Each ablation procedure was followed by in vivo T2-weighted MRI for edema and late-gadolinium enhancement (LGE) MRI for lesion characterization. For chronic lesions, the mean scar volumes at 25 W and 40 W were 77.8 ± 34.5 mm3 (n = 24) and 139.1 ± 69.7 mm3 (n = 12), respectively. The volume of chronic lesions increased (25 W: P < 0.001, 40 W: P < 0.001) with greater contact force. For acute lesions, the mean volumes of the lesion were 286.0 ± 129.8 mm3 (n = 19) and 422.1 ± 113.1 mm3 (n = 16) for 25 W and 40 W, respectively (P < 0.001 compared to chronic scar). On T2-weighted MRI, the acute edema volume was on average 5.6-8.7 times higher than the acute lesion volume and increased with contact force (25 W: P = 0.001, 40 W: P = 0.011).

CONCLUSION

With increasing contact force, there is a marginal increase in lesion size but accompanied with a significantly larger edema. The reversible edema that is much larger than the chronic lesion volume may explain some of the chronic procedure failures.

Update on sutureless thyroidectomy

INTRODUCTION

The Harmonic scalpel ("Focus" and the new version "Focus+") is one of the first devices for surgical simultaneous cutting and tissue coagulation which allows to obtain dissection and hemostasis by direct application of ultrasound and allows minimally invasive surgical procedures with minimal lateral thermal spread and, thus, minimal adjacent tissue destruction. The aim of the study is to complete the previous study that we made in 2014, based on the TT performed between January 2008 and December 2013, with new data about TT performed in our Surgical Division between January 2014 and December 2016 and compare the outcome using the Ultrasonic scalpel versus the device Ligasure in term of safety, operative time, overall drainage volume, complications, hospital stay.

PATIENTS AND METHODS

250 patients were randomized into two groups: Group A where Ultracision were used and Group B where the Ligasure device was used.

RESULTS

The results of the group A and of the Group B 2014-2016 have been compared with the results of the previous study and we found that they are similar, but asymptomatic hypocalcaemia increased in the patients of the new study.

CONCLUSIONS

We found that the use of Ultrasonic scalpel and Ligasure is effective both in the hemostasis of all vessels and in dissection of tissues and confirm the results of our first study without significant difference in the rate of post-operative morbidity with these two different energy based devices used.

Radiofrequency for Treatment of Refractory Epistaxis in Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia is a rare multi-systemic autosomal dominant disorder characterized by dysplasia of the vascular connective tissue and recurrent bleeding tendency. Epistaxis is the most common and earliest symptom. It is usually mild to moderate, however, in some patients it can be severe with significant interference in quality of life. We report a case of a patient with hereditary hemorrhagic telangiectasia, in which an episode of refractory epistaxis was treated with radiofrequency and fibrin sealant. Control of acute bleeding and elimination of telangiectasia was possible with this technique. After six months follow-up, there was no epistaxis recurrence. Various treatments for epistaxis in this disease have been described in the literature, but there is no consensus about the gold-standard procedure. Radiofrequency ablation of telangiectasia is a recent technique that has shown to be safe, effective and well tolerated, even in patients who underwent other previous treatments.

[Not Available]

Recently, radiofrequency ablation has been increasingly used for the treatment of thyroid nodules. The widespread introduction of this method, however, hampered by the lack of data on efficacy and safety of different devices that are currently on the market, the selection of the optimal mode of procedure also remains to be elucidated. Experimental data obtained during the application of the original patented device is presented. The results make it possible to move from ex vivo experiments to clinical practice.