Radiofrequency Thermal Therapy Research Articles

UP-02.042 Therapeutic Efficacy of Bipolar Radio Frequency Thermal Treatment for Patients with Benign Prostate Hyperplasia

In regarding of cost, ease of use and efficacy, bipolar radio frequency thermal therapy (Tempro system from Direx-Initia) for patients with benign prostate hyperplasia (BPH), especially dissatisfied with conventional medication and unwilling to surgery, shows effective improvement in the voiding symptom and the quality of life. We compared the clinical symptom and treatment result in order to evaluate the therapeutic efficacy.

Radiofrequency Treatment of Vaginal Laxity after Vaginal Delivery: Nonsurgical Vaginal Tightening

All women who have given birth vaginally experience stretching of their vaginal tissue. Long-term physical and psychological consequences may occur, including loss of sensation and sexual dissatisfaction. One significant issue is the laxity of the vaginal introitus. To evaluate safety and tolerability of nonsurgical radiofrequency (RF) thermal therapy for treatment of laxity of the vaginal introitus after vaginal delivery. We also explored the utility of self-report questionnaires in assessing subjective effectiveness of this device. Pilot study to treat 24 women (25-44 years) once using reverse gradient RF energy (75-90 joules/cm(2) ), delivered through the vaginal mucosa. Post-treatment assessments were at 10 days, 1, 3, and 6 months. Pelvic examinations and adverse event reports to assess safety. The author modified Female Sexual Function Index (mv-FSFI) and Female Sexual Distress Scale-Revised (FSDS-R), Vaginal Laxity and Sexual Satisfaction Questionnaires (designed for this study) to evaluate both safety and effectiveness, and the Global Response Assessment to assess treatment responses. No adverse events were reported; no topical anesthetics were required. Self-reported vaginal tightness improved in 67% of subjects at one month post-treatment; in 87% at 6 months (P<0.001). Mean sexual function scores improved: mv-FSFI total score before treatment was 27.6 ± 3.6, increasing to 32.0 ± 3.0 at 6 months (P < 0.001); FSDS-R score before treatment was 13.6 ± 8.7, declining to 4.3 ± 5.0 at month 6 post-treatment (P < 0.001). Twelve of 24 women who expressed diminished sexual satisfaction following their delivery; all reported sustained improvements on SSQ at 6 months after treatment (P = 0.002). The RF treatment was well tolerated and showed an excellent 6-month safety profile in this pilot study. Responses to the questionnaires suggest subjective improvement in self-reported vaginal tightness, sexual function and decreased sexual distress. These findings warrant further study.

A randomized double-blind controlled trial of intra-annular radiofrequency thermal disc therapy – A 12-month follow-up

A randomized double-blind controlled trial of intra-annular radiofrequency thermal disc therapy – A 12-month follow-up

Evolving treatments of virus-associated HCC new targets and drugs

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. The major etiologies and risk factors for HCC development are well defined and some of the multiple steps involved in hepatocarcinogenesis have been elucidated in recent years. The therapeutic options fall into five main categories: (1) surgical interventions, incl. liver transplantation, (2) percutaneous interventions, incl. ethanol injection and radiofrequency thermal ablation, (3) transarterial interventions, (4) radiation therapy and (5) drugs as well as gene and immune therapies. Because of the poor survival of the majority of patients, HCC prevention as well as early diagnosis and the development of novel systemic therapies for advanced disease are of paramount importance. In this context, recent data indicate that the 'targeted therapy' with monoclonal antibodies (mabs) or small molecule tyrosine kinase inhibitors (nibs) and other drugs seem to be effective to some degree. New technologies, including gene expression profiling and proteomic analyses, should allow to further elucidate the molecular events underlying HCC development and to identify novel diagnostic markers as well as therapeutic and preventive targets.

A randomized double-blind controlled trial of intra-annular radiofrequency thermal disc therapy – A 12-month follow-up

A randomized double-blind controlled trial of intra-annular radiofrequency thermal disc therapy – A 12-month follow-up

A randomized double-blind controlled trial of intra-annular radiofrequency thermal disc therapy – A 12-month follow-up

The discTRODE™ probe applies radiofrequency (RF) current, heating the annulus to treat chronic discogenic low back pain. Randomized controlled studies have not been published. We assessed the long-term effect and safety aspects of percutaneous intradiscal radiofrequency thermocoagulation (PIRFT) with the discTRODE™ probe in a prospective parallel, randomized and gender stratified, double-blind placebo-controlled study. Twenty selected patients with chronic low back pain and a positive one-level pressure-controlled provocation discography were randomized to either intra-annular PIRFT or intra-annular sham treatment. A blinded interim analysis was performed when 20 patients had been followed for six months. The 6-month analysis did not reveal any trend towards overall effect or difference between active and sham treatment for the primary endpoint: change in pain intensity (0–10). The inclusion of patients was therefore discontinued. After 12 months the overall reduction from baseline pain had reached statistical significance, but there was no significant difference between the groups. The functional outcome measures (Oswestry Disability Index, and SF 36 subscales and the relative change in pain) appeared more promising, but did not reach statistical significance when compared with sham treatment. Two actively treated and two sham-treated patients reported increased pain levels, and in both groups a higher number was unemployed after 12 months. The study did not find evidence for a benefit of PIRFT, although it cannot rule out a moderate effect. Considering the high number, reporting increased pain in our study, we would not recommend intra-annular thermal therapy with the discTRODE™ probe.

Snoring: a critical analysis of current treatment modalities. Does anything really work?

To determine the current options available for the treatment of snoring in the symptomatic patient, as this can be troublesome not only for the patient, but also the patient's bed partner. These include both surgical and non-surgical measures. The main themes that will be addressed include over-the-counter snoring aids, oral appliances, and surgical options. Surgical options include uvulopalatopharyngoplasty, laser-assisted uvulopalatoplasty, radiofrequency thermal ablation therapy, injection snoreplasty, and palatal implants. There are many alternatives available to treat snoring. None of these methods are without their negative aspects, therefore there is still a great need for further research and long-term follow-up studies to determine the best method. The final consensus of this review is that surgical options yield the best results, but these are often surgeon dependent, and none are free of relapses in snoring. Some options are also thought to offer several advantages, including less peri-operative pain and recovery time, less expense, and the ability to be performed in the office. The palatal implant system and radiofrequency thermal ablation appear to have relatively good outcomes, with little postoperative pain and relatively self-limited complications. They also have the convenience of an in-office procedure and less expense.

Development of a novel loosely wound helical coil for interstitial radiofrequency thermal therapy

We have developed a novel, radiofrequency thermal therapy device designed to improve local control of large solid tumours using heat in the range 55–90°C. The device is a solenoid or helical coil designed to be loosely wound inside a tumour and excited with radiofrequency energy. Typically, we associate a uniform axially directed magnetic field with a solenoid coil, which when time varying, results in an electric field inside the coil, which lies mainly in the circumferential direction. In addition to this magnetically induced electric field, there exists a less familiar axially directed electric field inside the coil. Previous investigators have demonstrated the presence of this secondary axial electric field both experimentally and theoretically. Our design exploits the size and uniformity of these electric fields, for heating and coagulating a large tissue volume with a single applicator. The loosely wound solenoid is constructed from Nitinol, an electrically conductive shape memory alloy that permits the minimally invasive percutaneous insertion of the coil through a single cannulating delivery needle. To demonstrate the potential of this device and to determine the optimal frequency of operation, phantom tissue models and finite-element calculation models using COMSOL 3.2® were used to characterize frequency- and geometry-dependent trends in absorption rate density (ARD), which is proportional to electric field intensity. Radial and axial ARD profiles were measured, calculated and evaluated to determine the frequency and geometry best suited for producing large, homogenous coagulation volumes. Based on the trade-off between radial and axial uniformities of the ARD profiles, a 2 cm diameter coil with a 4 cm length and 1 cm pitch, operated at 27.12 MHz, produced the optimal heating pattern, as determined using tissue-mimicking phantom models.

The use of a dispersive ground electrode with a loosely wound helical coil for interstitial radiofrequency thermal therapy

We have developed a novel, thermal therapy device designed to improve local control of large solid tumours using heat in the range 55–90 °C. The device is a helical coil designed to be loosely wound inside a tumour and excited with radiofrequency energy at 27.12 MHz. This design exploits the size and uniformity of the electric fields generated by magnetic induction inside this solenoidal geometry for heating and coagulating a large target volume. The use of the electrically conductive shape memory alloy Nitinol for the coil and an external ground plane permit the minimally invasive percutaneous insertion of the coil through a single cannulating delivery needle. To demonstrate the feasibility of this device, phantom models and finite-element models using COMSOL 3.2® were used to characterize uniformity of the radial and axial ARD (absorption rate density) profiles of different monopolar coil geometries. COMSOL 3.2® was also used to calculate temperature profiles and distributions produced by these coils in a non-perfused tissue-mimicking domain following a 10 min heating period. ARD results showed that optimum radial and axial uniformities were achieved with a 0.75 cm pitch and 3 cm length for a 1.5 cm diameter coil, and a 1.4 cm pitch and 4.2 cm length for a 2 cm diameter coil. These coils were able to produce lesions in excised bovine liver of 4 cm × 4.5 cm and 3.5 cm × 6.5 cm, respectively. Predicted temperature profiles showed similar profile sizes and shapes in a non-perfused domain, with the absolute temperature rise determined by the source input to the coil. These results demonstrate the potential of this interstitial, monopolar induction coil device for heating large tumours using a single applicator delivered through a single needle insertion.

Simultaneous measurements of local tissue temperature and blood perfusion rate in the canine prostate during radio frequency thermal therapy

Local tissue temperature and blood perfusion rate were measured simultaneously to study thermoregulation in the canine prostate during transurethral radio-frequency (RF) thermal therapy. Thermistor bead microprobes measured interstitial temperatures and a thermal clearance method measured the prostatic blood perfusion rate under both normal and hyperthermic conditions. Increase in local tissue temperature induced by the RF heating increased blood perfusion throughout the entirety of most prostates. The onset of the initial increase in blood perfusion was sometimes triggered by a temporal temperature gradient at low tissue temperatures. When tissue temperature was higher than 41 degrees C, however, the magnitude and the spatial gradient of temperature may play significant roles. It was found that the temperature elevation in response to the RF heating was closely coupled with local blood flow. The resulting decrease in or stabilization of tissue temperature suggested that blood flow might act as a negative feedback of tissue temperature in a closed control system. Results from this experiment provide insights into the regulation of local perfusion under hyperthermia. The information is important for accurate predictions of temperature during transurethral RF thermal therapy.

A case of small cell carcinoma of the esophagus detected incidentally by FDG-PET

Small cell carcinoma (SmC) of the esophagus is rare, and is sometimes impossible to detect by macroscopic inspection using an endoscope or histological examination of biopsied specimens. A 73-year-old man received F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) to evaluate the response to radiofrequency thermal ablation therapy for lung cancer. FDG-PET showed abnormal accumulation in the posterior mediastinum. Endoscopy disclosed ulcerous lesions with marginal elevation in the middle segment of the esophagus, but the biopsy specimen taken concurrently was not malignant histologically. FDG-PET, performed two months later, revealed abnormal accumulation in the suspect area, and the extent of accumulation was wider than previously. Histological examination of the specimen biopsied during the endoscopy led to a diagnosis of SmC. FDG-PET thus proved useful in the early detection of SmC.

Radiofrequency interstitial tissue ablation: wet electrode.

Minimally invasive methods for destroying tissue have been investigated for more than a decade, and growing interest has emerged in small probe or needle ablative techniques. Many energy sources that freeze or heat tissue have been studied. This paper discusses radiofrequency (RF) thermal therapy as delivered by the saline-augmented ("wet" or virtual) electrode. The technique modifies the electric field distribution and the resultant heat deposition within tissues by interstitially infusing a highly conductive electrolyte solution during the application of RF energy. We consider the mechanism of action of the saline-augmented probe, with emphasis on tissue electrical impedance, temperature distributions, and how the fluid circumvents the limitations of standard "dry" probes. If optimized for the particular application, the wet electrode can produce small to large ablation volumes quickly and controllably with a single needle stick. Because there is no desiccation or extremely high temperature, the tissue is not subjected to a phase shift of carbonization, which may reduce post-treatment inflammation and improve healing. The liquid RF electrode will find applications in the interstitial treatment of various tissues, including tumors.

Changes in dielectric properties at 460 kHz of kidney and fat during heating: importance for radio-frequency thermal therapy

We have developed a system to measure the changes due to heating to high temperatures in the dielectric properties of tissues in the radio-frequency range. A two-electrode arrangement was connected to a low-frequency impedance analyser and used to measure the dielectric properties of ex vivo porcine kidney and fat at 460 kHz. This frequency was selected as it is the most commonly used for radio-frequency thermal therapy of renal tumours. Tissue samples were heated to target temperatures between 48 and 78 °C in a hot water bath and changes in dielectric properties were measured during 30 min of heating and 15 min of cooling. Results suggest a time–temperature dependence of dielectric properties, with two separate components: one a reversible, temperature-dependent effect and the other a permanent effect due to structural events (e.g. protein coagulation, fat melting) that occur in tissues during heating. We calculated temperature coefficients of 1.3 ± 0.1% °C−1 for kidney permittivity and 1.6% °C−1 for kidney conductivity, 0.9 ± 0.1% °C−1 for fat permittivity and 1.7 ± 0.1% °C−1 for fat conductivity. An Arrhenius model was employed to determine the first-order kinetic rates for the irreversible changes in dielectric properties. The following Arrhenius parameters were determined: an activation energy of 57 ± 5 kcal mol−1 and a frequency factor of (6 ± 1) × 1034 s−1 for conductivity of kidney, an activation energy of 48 ± 2 kcal mol−1 and a frequency factor of 6 × 1028 s−1 for permittivity of kidney. A similar analysis led to an activation energy of 31 ± 4 kcal mol−1 and a frequency factor of (4.43 ±1) × 1016 s−1 for conductivity of fat, and an activation energy of 40 ± 4 kcal mol−1 and a frequency factor of 4 × 1022 s−1 for permittivity of fat. Structural events occurring during heating at different target temperatures as determined by histological analyses were correlated with the changes in the measured dielectric properties.

Optical method using fluence or radiance measurements to monitor thermal therapy

We present data from a two-region (coagulated and native tissue) Monte Carlo simulation in spherical geometry to assess the feasibility of using optical fluence and radiance information for determining the boundary of tissue coagulation during thermal therapy. Our results demonstrate that radiance offers directional sensitivity that might be useful in monitoring asymmetric coagulation growth. Preliminary experimental data from fluence monitoring of radio-frequency kidney thermal therapy further indicates that fluence information might be insufficient for determining the coagulation boundary. Therefore, in addition to optical fluence, we are also exploring the potential of radiance monitoring as a method for establishing the position of the coagulation boundary during radio-frequency thermal therapy.

The Uncertainty Of Radio Frequency Treatment Of Renal Cell Carcinoma: Findings At Immediate And Delayed Nephrectomy

Radio frequency thermal therapy for the ablation of renal cell carcinoma has been reported. Outcomes are usually measured by imaging alone. We have performed ex vivo and in vivo experiments using radio frequency in porcine models in our laboratory. We now report our early experience in the treatment of renal cell carcinoma in patients who underwent post-radio frequency radical or partial nephrectomy. We treated 10 patients diagnosed with small renal masses with radio frequency. All masses were biopsied before treatment. In 4 patients 5 renal cell carcinomas were treated with radio frequency after surgical exposure of the tumor followed immediately by partial or radical nephrectomy (acute group). Six other patients were treated percutaneously with ultrasound or computerized tomography guided radio frequency under local anesthesia and intravenous sedation 7 days before partial or radical nephrectomy (delayed group). A median of 2 radio frequency cycles was applied. Mean total heating time was 17 minutes 15 seconds. Specimens were analyzed grossly and histologically. Triphasic contrast-enhanced computerized tomography and/or magnetic resonance imaging was performed before and 7 days after radio frequency treatment in the delayed group. Mean radiological largest diameter of all 11 masses was 2.4 cm. and mean gross diameter was 2.2 cm. Pathological examination demonstrated residual viable tumor in approximately 5% of the volume in 4 of the 5 tumors in the acute group and in 3 of the 6 masses of the delayed group. In 1 delayed case the viable tumor appeared to be in contact with the renal vein. No significant complications were observed in 9 of the 10 patients. In 1 delayed case, a subcapsular hepatic hematoma, biliary fistula and pneumonia developed and resolved. Based on our experience, we continue to consider percutaneous radio frequency for the treatment of small renal cell carcinomas as a potentially curative therapy. However, complete tumor cell death appears to be difficult to achieve with our current treatment protocol. More phase II testing is indicated to ensure that this technique is an effective and reproducible treatment alternative.

ACUTE AND LONG-TERM OUTCOMES OF RADIO FREQUENCY BLADDER NECK SUSPENSION

A new treatment modality for women with stress urinary incontinence secondary to urethral hypermobility is radio frequency bladder neck suspension. Radio frequency energy is a form of electromagnetic energy that is reliable and highly controllable. This thermal therapy can produce well-defined areas of tissue heating. The technology has been used extensively in dermatological and orthopedic surgery for tissue shrinkage and ablation. Radio frequency thermal therapy is now being applied to the endopelvic fascia at the bladder neck and urethra for treating hypermobility in patients with stress urinary incontinence. The purported mechanism is shrinkage of the collagenated tissue that supports the bladder neck and proximal urethra. We report our acute and long-term experience with laparoscopic radio frequency bladder neck suspension for stress urinary incontinence. Enrolled in this prospective multicenter trial were 94 women with a mean age of 48.4 +/- 7.6 years who had urethral hypermobility with an average cotton swab angle change of 41 degrees and Valsalva leak point pressures greater than 90 cm. water at 250 ml. bladder capacity. Detrusor instability was excluded by cystometry. In all cases precisely controlled radio frequency energy was applied to the endopelvic fascia to heat and shrink the tissue. The primary end points were physician assessment of continence, patient reported pad use and the number of patient reported episodes of urinary incontinence daily 1, 3, 6 and 12 months after surgery. Average operative time was less than 60 minutes and 98% of the patients were discharged home from the recovery room. Treatment surface area decreased an average of 17% in length and 21% in width. Preoperatively 78% of patients had an average of 1 or more episodes of urinary incontinence daily. At 1, 3, 6 and 12 months there was an average of 1 or fewer episodes of urinary incontinence daily in 84.7%, 85.6%, 85.9% and 77.4% of patients, respectively, and at 12 months 83.5% reported being continent or improved. Preoperatively 41.2% of patients reported using 1 pad or less daily, while at 1, 3, 6 and 12 months 85.6%, 90.4%, 87.2% and 86.9%, respectively, required 1 pad or less daily. Urodynamic evaluation at 12 months showed no leakage during the Valsalva maneuver in 78% of cases. There were no major postoperative complications and the minor complication rate was 5.3%. Early results of thermal treatment of the endopelvic fascia indicate that radio frequency bladder neck suspension is safe and effective for improving stress urinary incontinence in women. The improvement in symptomatology appears to be durable in most patients at the 1-year followup. Longer followup is needed to assess the durability of results and it is currently in progress.

Hepatocellular carcinoma recurrence after percutaneous ablation therapy: helical CT patterns.

To categorize the helical computed tomographic (CT) intrahepatic recurrence patterns of hepatocellular carcinoma (HCC) after treatment with percutaneous ablation procedures. Double-phase helical CT studies of 67 patients with HCC recurrence were reviewed. The study population had undergone percutaneous ablation therapy procedures (multisession or single-session ethanol injection therapy, radiofrequency thermal ablation therapy, and interstitial laser photocoagulation therapy) for 120 HCC nodules. Four patterns were defined. (A) Enhancing tissue within the edge of the ablated nodule on arterial phase images (ingrowth): this pattern was seen in five treated lesions (4.2% of all treated nodules) in five patients (7.5% of all patients with recurrence) 3-7 months after treatment (mean = 4 months). (B) Enhancing tissue around the treated nodule but continuously to its border on arterial-phase images (outgrowth): this pattern was found in 12 (10%) treated lesions in 12 patients (18%) 3-6 months after ablation (mean = 4 months). (C) Enhancing tissue within the same segment of the treated nodule on arterial phase images (spread): this pattern was detected in 10 (8%) treated lesions in 10 patients (15%) 3-6 months after treatment (mean = 5 months). (D) Enhancing tissue within different segments from the treated nodule on arterial phase images (progression): this pattern was identified in 34 patients (51%) with 53 (44%) treated tumors 5-22 months after ablation (mean = 8 months). A mixed pattern was found in six subjects (9%) with seven (6%) treated nodules. Among the 61 patients with a nonmixed pattern, there were 85 treated nodules with persistent necrosis, 17 treated nodules with local recurrence (pattern A or B), and 107 new nodules due to nonlocal recurrence (pattern C or D). Portal phase enhanced images and especially unenhanced images showed a lower detection rate and a lower lesion-to-liver conspicuity score (for all patterns but mainly for pattern C). Four patterns of recurrence after percutaneous ablation procedures can be categorized on double-phase helical CT and are best depicted on arterial phase images. Knowledge of these patterns is relevant for early detection and may be helpful in understanding the recurrence mechanism.

Nonsurgical treatment of hepatocellular carcinoma.

1. Outcome from nonsurgical treatment is directly related to stage of hepatocellular cancer (HCC) and degree of liver function impairment. 2. Ablative percutaneous procedures, such as alcohol injection or radiofrequency thermal therapy, are most effective in the destruction of solitary tumors of 3 cm or less. 3. In most cases, nonsurgical treatments are not curative, but may slow tumor progression and can provide palliation. 4. Arterial embolization or chemoembolization has an antitumor effect, but it has not been shown to affect patient outcome. 5. Radiation therapy, chemotherapy, hormonal manipulation, and interferon have not been consistently effective in HCC. 6. Ablative procedures, embolization, and systemic chemotherapy should be avoided in patients with advanced cirrhosis.

A PROSPECTIVE STUDY OF TRANSPERINEAL PROSTATIC BLOCK FOR TRANSURETHRAL NEEDLE ABLATION FOR BENIGN PROSTATIC HYPERPLASIA: THE EMORY UNIVERSITY EXPERIENCE

We evaluate the feasibility, effectiveness and role of transperineal prostate block in providing anesthesia during minimally invasive radio frequency thermal therapy of the prostate. A total of 38 consecutive patients undergoing transurethral needle ablation for symptomatic benign prostatic hyperplasia were entered in this prospective study. All patients received transperineal prostatic block as the main method of anesthesia. A mixture of equal volumes of 1% lidocaine and 0.25% bupivacaine, each with epinephrine (1:100,000 concentration ratio) was used. Pain control during the instillation of transperineal prostatic block and transurethral needle ablation was assessed using a 10-point linear analog pain scale and questionnaire. Median patient age was 65.5 years (range 47 to 79), with 21% of men in the eighth decade of life. Median American Urological Association symptom score was 25.0 (range 14 to 35), bother score was 20.0 (11 to 28), quality of life score was 4.0 (3 to 6) and peak urinary flow rate was 8.9 cc per second (3.5 to 15.7). Median sonographic prostate volume was 35.0 cc (range 17 to 129). Median volume of anesthetic agent used was 40.0 cc (range 30 to 60) per case (1.1 cc solution per 1 cc prostate tissue). No adverse events were encountered. Median pain score was 3.3 (range 1 to 6) during instillation of transperineal prostatic block and 1.0 (0 to 6) during transurethral needle ablation. Transperineal prostatic block proved highly effective and was a satisfactory method of anesthesia during transurethral needle ablation as judged by postoperative questionnaire. No sedation, narcotic or analgesia was required. All procedures were performed in the outpatient cystoscopy suite or office setting without support of an anesthesia team or conscious sedation monitoring. Transperineal prostatic block is a safe, convenient, effective and satisfactory method of minimally invasive anesthesia for transurethral needle ablation of the prostate in an outpatient office setting. Elderly patients and those at high surgical risk can be treated safely using this approach. Considerable cost saving is seen secondary to omission of charges related to anesthesia team support, recovery room facility and conscious sedation monitoring.

Transurethral Needle Ablation (TUNATM)

Radiofrequency thermal therapy of the prostate is a new minimally invasive treatment for symptomatic benign prostatic hyperplasia (BPH). The procedure is called transurethral needle ablation (TUNA^TM). With TUNA, the inner region of the prostate is selectively ablated with temperatures approaching 90–100°C while the prostatic urothelium is preserved. The objective of this article is to discuss the basics of radiofrequency energy, instrumentation, surgical techniques, and to present an update of the clinical results as it applies to the treatment of BPH.