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Results for “Pulsed Radiofrequency Treatment”

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PubMed2026

Ultrasound-guided high-voltage vs conventional pulsed radiofrequency in elderly cervical radiculopathy: A randomized controlled trial.

BACKGROUND: Elderly patients with cervical radiculopathy present therapeutic challenges owing to comorbidities and medication-related risks. Long-term pharmacotherapy and surgical interventions are often suboptimal, necessitating evaluation of optimized pulsed radiofrequency strategies under image guidance. OBJECTIVES: This superiority trial compared the efficacy and safety of ultrasound-guided cervical nerve root high-voltage pulsed radiofrequency (HVP-PRF) versus conventional pulsed radiofrequency (C-PRF) for pain management in elderly patients with cervical radiculopathy. METHODS: This single-center, parallel-group, assessor-blinded randomized controlled trial enrolled patients aged 60-85 years with cervical radiculopathy, randomly assigned (1:1) to HVP-PRF (70 V) or C-PRF (45 V). Procedures were performed under ultrasound guidance with sensory/motor stimulation confirmation and temperature ≤42°C. The primary outcome was change in upper-limb radiating pain on the Numeric Rating Scale (ΔNRS) from baseline to 3 months. Secondary outcomes included Neck Disability Index (NDI), neck pain NRS, Patient Global Impression of Change, responder rates, rescue analgesia use, and adverse events. Follow-up occurred at 1 week, 1, and 3 months. RESULTS: A total of 104 patients were randomized and 101 received treatment. At 3 months, HVP-PRF demonstrated significantly greater radiating pain improvement versus C-PRF (adjusted mean difference 1.24, 95% CI 0.46-2.02, P=0.002). Functional improvement (NDI) was superior in the HVP-PRF group at 3 months (AMD 6.47, 95% CI 2.11-10.83, P=0.004). Responder rates (≥50% pain reduction) were higher with HVP-PRF at 3 months (68.75% vs. 42.22%, OR 3.01, P=0.011) and 6 months (65.22% vs. 43.18%, OR 2.52, P=0.035). Rescue analgesic use was lower in the HVP-PRF group during 1-3 months intervals (both P<0.05). Adverse event rates were comparable (27.45% vs. 32.00%). CONCLUSION: Under ultrasound visualization and electrical stimulation-based target confirmation with temperature control ≤42°C, HVP-PRF provided greater and more durable relief of upper limb radiating pain compared with C-PRF in elderly patients with cervical radiculopathy, with a comparable safety profile.

Humans↗

PubMed2026

Incidence of silent cerebral lesions during pulsed field ablation for paroxysmal atrial fibrillation.

BACKGROUND: Radiofrequency catheter ablation (RFCA) is a first-line treatment for paroxysmal atrial fibrillation (PAF). Complications such as silent cerebral lesion (SCL) may occur during ablation. Pulsed field ablation (PFA) is a non-thermal method thatablates cardiac tissue via irreversible electroporation. Limited studies have reported the incidence of SCL during PFA, with highly variable results. However, randomized controlled trials (RCTs) remain scarce. The objective of this study was to compare perioperative SCL incidence between PFA and RFCA, and to identify risk factors for SCL during PFA. METHODS: In this prospective pilot RCT (ChiCTR2400088774), 62 patients with PAF were randomized 1:1 to undergo PFA or RFCA. Cerebral MRI (3.0 T) was performed preoperatively and 24-48h postoperatively. SCL was defined as a new acute brain lesion on MRI without neurological deficits. Baseline and surgical data of the patients were collected. RESULTS: SCL was detected post-procedure in 6.45% (2/31) in the RFCA group, 12.90% (4/31) in the PFA group. No statistically significant difference in the incidence of postoperative SCL was detected between the two groups (p = 0.67). Left atrium dimension (LAD), left atrial operation time (LAOT), left ventricular end-diastolic dimension (LVEDD), and total operation time (TOT) were significantly higher in SCL group than those in no-SCL group (p < 0.05) through univariate analyses. CONCLUSIONS: SCL incidence was 12.90% in the PFA group versus 6.45% in the RFCA group. While no statistically significant difference was detected between two groups, the numerically higher rate in the PFA group warrants larger studies to evaluate cerebral safety associated with PFA.

Humans↗

PubMed1990

Influence of radiofrequency radiation on chromosome aberrations in CHO cells and its interaction with DNA-damaging agents.

A limited number of contradictory reports have appeared in the literature about the ability of radiofrequency (rf) radiation to induce chromosome aberrations in different biological systems. The technical documentation associated with such reports is often absent or deficient. In addition, no information is available as to whether any additional genotoxic hazard would result from a simultaneous exposure of mammalian cells to rf radiation and a chemical which (by itself) induces chromosome aberrations. In the work described, we have therefore tested two hypotheses. The first is that rf radiation by itself, at power densities and exposure conditions which are higher than is consistent with accepted safety guidelines, can induce chromosome aberrations in mammalian cells. The second is that, during a simultaneous exposure to a chemical known to be genotoxic, rf radiation can affect molecules, biochemical processes, or cellular organelles, and thus result in an increase or decrease in chromosome aberrations. Mitomycin C (MMC) and Adriamycin (ADR) were selected because they act by different mechanisms, and because they might put normal cells at risk during combined-modality rf radiation (hyperthermia)-chemotherapy treatment of cancer. The studies were performed with suitable 37 degrees C and equivalent convection heating-temperature controls in a manner designed to discriminate between any thermal and possible nonthermal action. Radiofrequency exposures were conducted for 2 h under conditions resulting in measurable heating (a maximum increase of 3.2 degrees C), with pulsed-wave rf radiation at a frequency of 2450 MHz and an average net forward power of 600 W, resulting in an SAR of 33.8 W/kg. Treatments with MMC or ADR were for a total of 2.5 h and encompassed the 2-h rf radiation exposure period. The CHO cells from each of the conditions were subsequently analyzed for chromosome aberrations. In cells exposed to rf radiation alone, and where a maximum temperature of approximately 40 degrees C was achieved in the tissue culture medium, no alteration in the frequency from 37 degrees C control levels was observed. Relative to the chemical treatment with MMC alone at 37 degrees C, for two different concentrations, no alteration was observed in the extent of chromosome aberrations induced by either simultaneous rf radiation exposure or convection heating to equivalent temperatures. At the ADR concentration that was used, most of the indices of chromosome aberrations which were scored indicated a similar result.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1987

Estrogen induces premature luteal regression in rhesus monkeys during spontaneous menstrual cycles, but not in cycles driven by exogenous gonadotropin-releasing hormone.

Administration of exogenous estradiol during the mid- to late luteal phase of the menstrual cycle results in premature regression of the corpus luteum. The present study was initiated to identify the site of action of estrogen as well as to determine why administration of estrogen during the early luteal phase of the menstrual cycle does not result in luteolysis. Based upon extant literature, we hypothesized that estrogen and progesterone synergize to promote premature luteal regression. We tested this hypothesis in intact, spontaneously cycling rhesus monkeys by inserting estradiol, progesterone, or estrogen plus progesterone capsules on days 2 through 6 of the luteal phase. Insertion of estrogen or progesterone capsules alone did not advance luteolysis compared with the effect of control empty implants (n = 3). In contrast, insertion of estrogen plus progesterone implants on days 2 through 6 of the luteal phase resulted in a significant lowering of serum progesterone concentrations, and menses was advanced 5-6 days compared with control cycles. On the basis of these findings in spontaneously cycling monkeys, we speculated that estrogen treatment causes luteal regression only in the presence of a progesterone-mediated decrease in LH pulse frequency. To test this hypothesis, we used rhesus monkeys whose endogenous gonadotropin secretion was abolished by either placement of radiofrequency lesions in the mediobasal hypothalamus or transection of the hypothalamic-pituitary stalk. Ovulatory menstrual cycles were restored by pulsatile administration of exogenous synthetic GnRH. Insertion of estradiol capsules during the luteal phase into animals whose gonadotropin pulse frequency was set at either one pulse per h or one pulse per 8 h failed to cause premature luteal regression (n = 4). These findings indicate that whereas estrogen promotes luteal regression in intact, spontaneous cycling rhesus monkeys, it does not do so in animals whose gonadotropin secretion is controlled by exogenous GnRH. On the basis of these observations, we conclude that the hypothalamus is a major site of action of estrogen in the initiation of luteal regression in macaques.

Animals↗

PubMed1992

[Radiofrequency energy as treatment for arrhythmias in patients with accessory atrioventricular pathways].

OBJECTIVE: Evaluation of the use of radiofrequency energy to interrupt accessory atrioventricular pathways. DESIGN: Prospective study. SETTING: University Hospital Maastricht. METHOD: The outcome is presented of radiofrequency catheter ablation of accessory atrioventricular pathways in our first 50 consecutive patients, with a total of 54 accessory pathways. All but one patient suffered from symptomatic tachycardias. A catheter electrode was positioned next to the accessory pathway and 30 second pulses of 40 W radiofrequency energy were used to interrupt the connection. RESULTS: Complete block in conduction was accomplished in 44/54 (81%) of accessory pathways. No complications occurred. Success rate, procedure time and radiation dose were found to be related to the location of the accessory connection. The highest success rate was found in left free wall pathways (24/26; 92%), the lowest in right lateral pathways which seldom occur (1/4; 25%). The total procedure took 1-6 hours. The maximal duration of radiographic imaging was 2.5 hours. CONCLUSION: Although insufficient information on long-term efficacy is available, current results support the use of radiofrequency ablation of accessory pathways in institutions with expertise in the invasive management of cardiac arrhythmias. Technical improvements leading to reduction in procedure time and radiation dose will facilitate acceptance of this technique by patient and operator.

Adolescent↗

PubMed1989

Histopathological appraisal of carbon-dioxide laser dorsal root entry zone (DREZ) lesions in primates.

Dorsal Root Entry Zone (DREZ) thermocoagulation using radiofrequency has successfully been employed in the treatment of various deafferentation pain syndromes. The ability of surgical lasers to produce discrete lesions with precision has prompted their use in DREZ lesioning. The effects of carbon-dioxide laser induced DREZ lesions in the primate spinal cord were studied in the Bonnet monkey and the parameters necessary to produce a histologically ideal DREZ lesion were evaluated. Lesions were made with 10, 15 and 20 Watts power for pulse durations of 100 to 400 milliseconds at a constant beam spot size of 0.4 mm. It was found that histologically ideal lesions were produced with 20 Watts of power and a pulse duration of 300 milliseconds and with 15 Watts power and 400 millisecond pulse duration. The lesion lengths and widths at different parameters were also comparatively evaluated. The postulated mechanisms of deafferentation pain and the possible mode of action of DREZ lesions in management of pain are also reviewed.

Animals↗

PubMed1990

An evaluation of radiofrequency exposure from therapeutic diathermy equipment in the light of current recommendations.

Shortwave and microwave diathermy equipment use by physiotherapy departments in Grampian Region has been studied. Stray electric and magnetic fields close to equipment have been measured and compared with exposure levels recommended by the INIRC and the NRPB. Fields above the recommended whole body levels extend to 0.5-1.0 m from the electrodes and cables for continuous wave (cw) shortwave equipment, and up to 0.5 m for microwave units and pulsed shortwave models. Operators were exposed to local fields above these values for 2 - 3 min during cw shortwave treatments, but rarely exceeded the recommended exposure. However, short localised exposures to high fields, which can occur if the operator moves close to the electrodes or cables, could exceed these limits. Physiotherapists are advised to remain at a distance of at least 1 m during cw treatments, and not to approach within 0.5 m of the electrodes and cables even for a short period.

Diathermy↗

PubMed1989

Absence of mutagenic interaction between microwaves and mitomycin C in mammalian cells.

Evidence in the literature from in vitro and in vivo studies as to whether or not radiofrequency radiation (RFR) in the microwave range is mutagenic is predominantly negative, with some positive reports. No evidence is available as to whether RFR will alter the mutagenic activity of genotoxic chemicals during a simultaneous exposure, a likely real-life situation. Two hypotheses have been proposed: a) that RFR by itself can cause mutations in a mammalian cell in vitro assay system; and b) that a simultaneous exposure to RFR during a chemical treatment of the cells with a known genotoxic agent, mitomycin C (MMC), will alter the extent of mutagenesis induced by the treatment of the cells by the chemical alone. These studies were performed using the forward mutation assay at the thymidine kinase locus in L5178Y mouse leukemic cells. The pulsed wave RFR was broadcast from an antenna horn at a frequency of 2.45 GHz. The power density was 48.8 mW/cm2 and the measured specific absorption rate (SAR) in this system was 30 W/kg (600 W forward power), which is well above current safety guidelines. The conclusions from five different experiments, employing three different concentrations of MMC, were that a) RFR exposure alone, at moderate power levels which resulted in a temperature increase in the cell culture medium of less than 3 degrees C, is not mutagenic; and b) when cells are simultaneously treated with MMC and RFR at these same moderate power levels, the RFR does not affect either the inhibition of cell growth or the extent of mutagenesis resulting from the treatment with the chemical MMC alone.

Animals↗

PubMed1987

Effects of radiofrequency radiation and simultaneous exposure with mitomycin C on the frequency of sister chromatid exchanges in Chinese hamster ovary cells.

Chinese hamster ovary (CHO) cells were exposed for 2 hr with and without mitomycin C (MMC) (1 X 10(-8)M) to pulsed wave radiofrequency radiation (RFR) at 2450 MHz. The repetition rate of 25,000 pulses per sec (pps), pulse width of 10 microseconds, and exposure geometry used, resulted in a specific absorption rate (SAR) of 33.8 W/kg. The following exposure regimens were used: a 37 degrees C water bath control; a water bath temperature control (TC) in which the continuously monitored medium temperature closely followed the temperature rise in the RFR-exposed flasks; and the RFR-exposed cells in a water bath set at 37 degrees C prior to exposure. RFR exposure resulted in a maximum cell culture medium temperature of 39.2 degrees C. In the absence of MMC, there was no significant increase in sister chromatid exchange (SCE) in the RFR-exposed or TC groups over that of the 37 degrees C control. When a simultaneous treatment of RFR and MMC occurred there was no statistical difference in SCE frequency from that caused by chemical treatment alone.

Animals↗

PubMed1991

High success rate of atrioventricular node ablation with radiofrequency energy.

Radiofrequency current was introduced as an alternative energy source for transcatheter ablation of cardiac arrhythmias to avoid the complications associated with direct current shocks. Initial use of radiofrequency current for complete ablation of the atrioventricular (AV) node yielded only moderate success rates, presumably because of the small size of electrodes and difficulty in localizing the AV node. The use of a larger 4-mm tip electrode for delivery of radiofrequency current and a method to better localize the AV node were prospectively studied in 32 patients undergoing catheter ablation of the AV node. There were 21 men and 11 women with a mean age of 62 +/- 12 years. Complete AV block was achieved immediately in 31 patients (97%) and it persisted in 28 patients (88%) during a mean follow-up period of 12 +/- 6 months. Three patients who had return of AV condition required no drug therapy for control of ventricular rate during atrial fibrillation. The number of radiofrequency pulses used to achieve complete AV block ranged from 1 to 5 (mean 1.9 +/- 1.1). In greater than 50% of the cases, only one radiofrequency pulse was required. The mean power and duration of radiofrequency pulses were 21.2 +/- 4.5 W and 33 +/- 15 s, respectively. All patients developed a stable junctional escape rhythm within 45 min of successful ablation. The QRS configuration was unchanged in 30 patients. One patient had a new right bundle branch block after ablation. There were no complications related to the ablation procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Design and implementation of magnetization transfer pulse sequences for clinical use.

The transfer of magnetization between a free and a bound pool of spins is described in terms of the respective longitudinal relaxation times and the life times of spins in each pool. The effect of an off resonance radiofrequency (RF) pulse in producing saturation in the bound pool and a consequent decrease in both the available longitudinal magnetization and the T1 of spins in the free pool is described. The effects of increasing duration of the saturating RF pulse on image pixel signal intensity were used to determine values for the decrease in both T1 and the available magnetization in gray and white matter of the brain as well as in muscle, fat, and CSF. At 0.15 T the available magnetization of muscle was reduced by approximately 60% and its T1 was decreased from 350 to 150 ms. The available magnetization of white and gray matter was reduced by 40% and their values of T1 were reduced by 80-110 ms. The reduction in available magnetization was used to increase contrast on proton density weighted or T2-weighted SE pulse sequences. These changes were also used to design inversion recovery (IR) pulse sequences with particular contrast properties. A short inversion time (TI) magnetization transfer (MT) IR (MT-STIR) pulse sequence was used to reduce the signal from normal muscle to zero to produce an angiographic effect in the leg. Increased tissue contrast was observed with a T2-weighted (MT-SE) sequence in a patient with bilateral cerebral infarction and with an MT-IR pulse sequence in a patient who had an intracranial hematoma. Three patients with cerebral tumors showed high lesion contrast with MT-STIR sequences. Components within two tumors were changed to different degrees by MT and in one case change in the brain attributable to recent radiotherapy treatment was only identified with an MT-STIR sequence. Magnetization transfer can be used to manipulate both the available longitudinal magnetization and the T1 of normal and abnormal tissues. The changes in tissue contrast produced by this can be very substantial and are likely to be of importance in clinical imaging.

Adult↗

PubMed1987

Radiofrequency capacitive hyperthermia for deep-seated tumors. I. Studies on thermometry.

The thermometry results of radiofrequency (RF) capacitive hyperthermia for 60 deep-seated tumors in 59 patients are reported. Hyperthermia was administered regionally using two RF capacitive heating equipments which the authors have developed in cooperation with Yamamoto Vinyter Company Ltd., (Osaka, Japan). Intratumor temperatures were measured by thermocouples inserted through angiocatheters which were placed 5 cm to 12 cm deep into the tissues. Tumor center temperatures were measured for 307 treatments in all tumors; thermal distributions within tumors and surrounding normal tissues were obtained for 266 treatments of 53 tumors by microthermocouples. Thermometry results obtained were summarized as follows. A maximum tumor center temperature greater than 43 degrees C and 42 degrees C to 43 degrees C was obtained in 23 (38%) and 14 (23%) of the 60 tumors respectively. The time required to reach 43 degrees C in the tumor center was within 20 minutes after the start of hyperthermia in 87% of tumors heated to more than 43 degrees C. Temperature variations within a tumor exceeded 2 degrees C in 81% of tumors heated to more than 43 degrees C. The lowest tumor temperature greater than 42 degrees C was achieved in six of the 53 tumors (11%). Of 42 tumors in which temperatures of the subcutaneous fat, surrounding normal tissues, and the tumor center were compared, 24 (57%) showed the highest temperature in the tumor center and ten (24%) in the subcutaneous fat. When the heating efficacy was assessed in terms of a maximum tumor center, it great deal depended on the treatment site, tumor size, thickness of subcutaneous fat, and tumor type. Tumors in the head and neck, thorax, lower abdomen, and pelvis could be heated better than tumors in the upper abdomen. Greater heating efficacy was shown in patients with large, hypovascular tumors, and with the subcutaneous fat measuring less than 15 mm thick. The predominant limiting factor for power elevation was pain associated with heating. Systemic signs including increases in pulse rate and body temperature were not serious and seldom became limiting factors for power elevation. Our thermometry results indicate that the advantages of deep RF capacitive heating are its applicability to various anatomic sites and negligible systemic effects. The disadvantages are that its primary usefulness is limited to patients with thin subcutaneous fat and with large or hypovascular tumors.

Adult↗