Search Results (14)

Background: Chronic thoracic pain is commonly caused by thoracic facet dysfunction, intercostal neuralgia, surgery, or thoracic pain secondary to cancer and is present in approximately 15% of the population. Conventional treatments, including pharmacotherapy and transcutaneous electrical nerve stimulation, are often ineffective and are often associated with poorly tolerated adverse effects. Cooled radiofrequency ablation (c-RFA) is a minimally invasive procedure that uses radiofrequency energy delivered through a probe to lesion the targeted nerve and provide significant and lasting relief. Methods: This study was a retrospective analysis of data extracted from UW-Health Electronic Medical Health records from October 2015 through June 2024. Patient data were collected, including diagnosis, pre-operative pain score, post-operative pain score, duration of relief, age, sex, and BMI. A two-tailed paired t-test was used to analyze the pre-operative and post-operative pain scores. A p-value < 0.05 was considered significant. Results: A total of 111 thoracic c-RFA procedures were reviewed; 43 were excluded due to absent pre-operative or post-operative pain scores in medical records. A total of 68 procedures were included in the analysis, comprising 55 patients: 25 females and 30 males with an average age of 51.31 ± 18.22 years and a BMI of 29.79 ± 6.48 kg/m². Improvement in pain scores was reported in 77.94% (n = 53), 16.18% (n = 11) reported no change, and 5.88% (n = 4) reported worsening pain. Patients reported an average pre-operative pain score of 5.98 (M = 5.98, SD = 1.91) and an average post-operative pain score of 3.06 (M = 3.06, SD = 2.52); this achieved significance (p < 0.0001). Of the 77.94% (n = 53) charts that noted improvement, there is an average of 62.83 ± 28.48% reduction from their pre-operative pain scores. The average duration of relief lasted 11.85 ± 13.42 months. Conclusions: This study supports the efficacy and safety of c-RFA as a minimally invasive therapy for chronic thoracic pain refractory to conservative measures. Full article

Introduction: Radiofrequency ablation (RFA) of the genicular nerve is an increasingly common treatment for chronic knee pain, refractory to conservative measures. However, RFA often provides significant but temporary relief, and patients return for repeat RFAs for the treatment of their pain. This study investigates the efficacy of repeat RFAs compared to the initial RFA for patients who receive repeat RFAs for chronic knee pain. Methods: This study is a retrospective chart review and analysis that was conducted between 2015 and 2023. Groups were determined by the number of RFA procedures that patients received, and a one-tailed ANOVA test was performed to assess the statistical significance of the initial RFA and the three repeat RFA groups. A one-way ANOVA was performed to analyze statistical differences between percent improvement, preoperative pain scores, and the duration of improvement using the visual analog scale (VAS). A p-value of statistical significance was set at p < 0.05. A paired two-tailed T-test was carried out, individually comparing the initial RFA to the three repeat groups for percent improvement. A paired t-test was also carried out to compare initial and first repeat RFAs for preoperative pain score and duration of improvement. Results: A total of 42 patients underwent repeat RFA procedures, with 8 receiving bilateral treatments, totaling 50 knees and 116 procedures. The original RFA group demonstrated a mean percent improvement of 75% ± 25% (mean ± SD) and a duration of improvement of 9.46 ± 5.45 months. The first repeat group had a mean percent improvement of 66% ± 29% and a duration of improvement of 8.77 ± 7.32 months. The second repeat group had a mean percent improvement of 67% ± 24% and a duration of improvement of 10.00 ± 2.45 months. The third repeat group had a mean percent improvement of 85% ± 20% and a duration of improvement of 4.00 months. ANOVA revealed no statistically significant differences among the groups in preoperative scores (p = 0.40), percent improvement (p = 0.25), or duration of improvement (p = 0.79). Paired t-tests showed a significant decrease in percent improvement in the first repeat RFA compared to the original RFA (p = 0.04), but no significant differences were observed in preoperative scores (p = 0.057) or duration of improvement (p = 0.175). No significant differences were found in percent improvement via paired T-test between the original RFA and the second (p = 0.75) or third repeats (p = 0.21). Conclusions: The repeat RFA of genicular nerves retains a clinically significant level of pain reduction for chronic knee pain. However, this study demonstrated decreased pain relief following the first repeat RFA compared to the initial RFA when analyzing individual knees sequentially via a paired T-test. An analysis of initial, first, second, and third repeat groups via ANOVA showed no difference in percent improvement, duration of pain relief, or preoperative pain scores. Full article

Background/Objectives: Knee osteoarthritis (KOA) is a degenerative joint disease typically managed with conservative treatments, such as anti-inflammatory medications and intra-articular hyaluronic acid injections; however, advanced cases may eventually require surgical intervention. Recently, cooled radiofrequency ablation (CRFA) has emerged as a novel treatment option for alleviating KOA-related pain by temporarily disabling pain-transmitting nerves. This study evaluated the short-term effects of CRFA on pain relief and walking ability in KOA patients, with a specific focus on functional improvements in walking capacity. Methods: This study included 58 patients (71 knees) with KOA who underwent CRFA after experiencing inadequate pain control with conservative treatments. The cohort consisted of 28 men and 30 women, with a mean age of 75.2 years (55–90). Under ultrasound guidance, CRFA was performed on the superior lateral geniculate nerve, superior medial geniculate nerve, and inferior medial geniculate nerve, with each targeted nerve ablated. Pre- and post-procedural evaluations (one month after CRFA) included assessments of visual analog scale (VAS) scores for pain at rest and during walking, range of motion (ROM), knee extensor strength, walking speed, and gait stability. Results: Significant improvements in the mean VAS (rest/walking) and mean walking speed (comfortable/maximum) were observed following CRFA. However, no significant changes were noted in ROM, knee extensor strength, or walking stability. Conclusions: These findings suggest that rehabilitation may be essential to further enhance walking stability. Overall, CRFA appears to be a promising short-term treatment option for reducing VAS pain scores and enhancing walking speed in patients with KOA. Full article

Low back pain (LBP) affects over 60% of individuals in their lifetime and is a leading cause of disability and increased healthcare expenditure. Facet joint pain (FJP) occurs in 27% to 40% of LBP patients but is often overlooked or misdiagnosed. Additionally, there is no clear correlation between the clinical examination, radiological findings, and clinical presentation, complicating the diagnosis and treatment of FJP. This narrative review aims to provide an overview of the literature regarding facet joint pain and discusses the utility of medial branch blocks (MBBs) and intra-articular (IA) injections as diagnostic and therapeutic tools prior to radiofrequency ablation (RFA). RFA is considered the gold standard for managing FJP, employing techniques that include precise needle placement and stimulation parameters to disrupt pain signals. Promising alternatives such as cooled RFA and cryodenervation require further research on their long-term efficacy and safety. Endoscopic denervation and multifidus stimulation are emerging therapies that may benefit chronic LBP patients, but additional research is needed to establish their effectiveness. When conservative management fails, RFA provides significant and lasting relief in well-selected patients and has a favourable safety profile. The current literature does not support surgical interventions for FJP management. Full article

Background and Objectives: Radiofrequency catheter ablation (RFCA) is a highly successful intervention. By comparing the lesion changes in prostate parenchymal and striated muscle tissues after RFCA with and without cooling, it was possible to assess the correlation between the shape regularity, area, and perimeter of the thermal lesion, and to predict the geometric shape changes of the lesions. Materials and Methods: A standard prostate and striated muscle RFCA procedure was performed on 13 non-purebred dogs in two sessions: no cooling and cooling with 0.1% NaCl solution. Microtome-cut 2–3 µm sections of tissue samples were stained with haematoxylin and eosin and further examined. The quotient formula was employed to evaluate the geometric shape of the damage zones at the ablation site. Results: The extent of injury following RFCA in striated muscle tissue was comparable to that in prostate parenchymal tissue. Regression analysis indicated a strong and positive relationship between area and perimeter in all experimental groups. In the experimental groups of parenchymal tissues with and without cooling, an increase in the area or perimeter of the damage zone corresponded to an increase in the quotient value. A similar tendency was observed in the striated muscle group with cooling. However, in the striated muscle group without cooling, an increase in lesion area or perimeter lowered the quotient value. Standardised regression coefficients demonstrated that in the striated muscle with cooling, the damage zone shape was more determined by area than perimeter. However, in the parenchymal tissue, the perimeter had a more substantial impact on the damage zone shape than the area. Conclusions: The damage area and perimeter have predictive power on the overall shape regularity of damage zone geometry in both striated muscles and parenchymal tissue. This approach is employed to achieve a balance between the need for tumour eradication and the minimisation of ablation-induced complications to healthy tissue. Full article

Background: Increasing evidence supporting the clinical effectiveness of cooled radiofrequency ablation (RFA) therapy for genicular nerves in patients with chronic knee osteoarthritis (OA) exists. However, no study has been conducted to eliminate the potential influence of a placebo effect associated with this procedure. Therefore, we evaluated the efficacy of cooled RFA compared with a sham procedure in patients with painful knees due to OA. Methods: In this double-blind, randomized, controlled study, participants were randomly assigned to receive cooled RFA of the knee (cooled RFA group, n = 20) or a sham procedure (sham group, n = 20). The primary outcome was the proportion of successful responders at the three-month follow-up. The secondary outcomes were successful responders at one and six months; pain intensity of the knee; functional status; medication; and satisfaction at one, three, and six months after the procedures. Results: For the primary outcome, the successful responder rate was significantly higher in the cooled RFA group (76.5%) than in the sham group (33.3%) (p = 0.018). For the secondary outcome, more successful responders were observed in the cooled RFA group than in the sham group at one and six months after the procedure (p = 0.041 and 0.007, respectively). The decreased knee pain intensity was maintained throughout the six-month follow-up period in the cooled RFA group. No differences were observed in functional status, medication change, or satisfaction in both groups. Conclusions: The cooled RFA of genicular nerves offers significant pain relief and surpasses the effects attributable to a placebo. Full article

Background and Objectives: The interspace between the popliteal artery and the posterior capsule of the knee (iPACK) block has been widely used in perioperative settings to control posterior knee pain and can additionally be used for chronic knee pain. In this cadaveric study, we aimed to investigate the needle tip position and its proximity to the articular branch of the tibial nerve (ABTN) during an iPACK-targeted radiofrequency procedure. Materials and Methods: An ultrasound-guided iPACK block was performed on 20 knees of 10 cadavers. We injected 0.1 mL each of blue and green gelatinous dye near the tibial artery (point A) and posterior knee capsule (point B), respectively, and evaluated the spread of both around the ABTN. For a hypothetical conventional radiofrequency ablation (RFA) lesion (diameter, 2.95 mm) and cooled RFA lesion (diameter, 4.9 mm), we counted the number of specimens in which the ABTNs would be captured. Results: The percentage of specimens in which the ABTN would be captured by a cooled RFA lesion was 64.71% at point A and 43.75% at point B (p = 0.334). Meanwhile, the percentage of specimens in which the ABTN would be captured by a conventional RFA lesion was 58.82% from point A and 25% from point B (p = 0.065). Conclusions: When performing an RFA-based iPACK block, the needle tip may be positioned either lateral to the tibial artery or in the space between the posterior knee capsule and the tibial artery. However, more studies with larger samples are needed to verify these results before the clinical use of this procedure can be recommended. Full article

Background and Objectives: Prostate cancer is on the rise in the European Union, and radiofrequency ablation (RFA) is one of the minimally invasive treatment options used for its treatment. Therefore, the aim of this study was to investigate and analyze the effects of RFA on prostate tissues. Materials and Methods: A standard prostate RFA procedure was performed on 13 non-purebred dogs in three sessions: no cooling (NC), cooling with a 0.1% NaCl solution (C.01), and cooling using a 0.9% NaCl solution (C.09). Microtome-cut 2–3 µm sections of prostate samples were stained with hematoxylin and eosin and further examined. Results: A histopathologic evaluation identified four zones of exposure: direct, application, necrosis, and transitional, as the damage on tissues decreased going further from the ablation site. The areas and perimeters of these zones were calculated, and geometric shapes of ablative lesions were evaluated using the quotient formula. Areas and perimeters of prostate tissue lesions in the NC and C.09 sessions were of similar size, whereas those found in C.01 were statistically significantly smaller. Lesions observed in session C.01 were of the most regular geometric shape, while the most irregular ones were found in session C.09. The shapes of lesions closest to the ablation electrode were the most irregular, becoming more regular the further away from the electrode they were. Conclusions: Prostate RFA leads to tissue damage with distinct morphological zones. Notably, the prostate lesions were the smallest and the most regular in shape after RFA procedures using the 0.1% NaCl cooling solution. It can be argued that smaller ablation sites may result in smaller scars, thus allowing for faster tissue healing if the blood flow and innervation at the ablation site are not compromised. Full article

(1) Background: A combination of radiofrequency (RF) volumetric heating and convection cooling has been proposed to realize plaque ablation while protecting the endothelial layer. However, the depth of the plaque and the thickness of the endothelial layer vary in different atherosclerotic lesions. Current techniques cannot be used to achieve penetrating heating for atherosclerosis with two targets (the specified protection depth and the ablation depth). (2) Methods: A tissue-mimicking phantom heating experiment simulating atherosclerotic plaque ablation was conducted to investigate the effects of the control parameters, the target temperature (T_target), the cooling water temperature (T_f), and the cooling water velocity (V_f). To further quantitatively analyze and evaluate the ablation depth and the protection depth of the control parameters, a three-dimensional model was established. In addition, a conformal penetrating heating strategy was proposed based on the numerical results. (3) Results: It was found that T_target and T_f were factors that regulated the ablation results, and the temperatures of the plaques varied linearly with T_target or T_f. The simulation results showed that the ablation depth increased with the T_target while the protection depth decreased correspondently. This relationship reversed with the T_f. When the two parameters T_target and T_fwere controlled together, the ablation depth was 0.47 mm–1.43 mm and the protection depth was 0 mm–0.26 mm within 2 min of heating. (4) Conclusions: With the proposed control algorithm, the requirements of both the ablation depth and the endothelium protection depth can be met for most plaques through the simultaneous control of T_target and T_f. Full article

Although epicardial bipolar radiofrequency ablation should diminish the risk of esophageal thermal injury in comparison to an endocardial ablation, cases of lethal atrio-esophageal fistula have been reported. To better understand this risk and to reduce the possibility of a thermal injury, we monitored the esophageal temperature with the Circa S-Cath™ temperature probe during and immediately after the ablation while implementing three procedural safety measures. Twenty patients (15 males; 63 ± 10 years) were prospectively enrolled (November 2019–February 2021). All patients underwent an epicardial ablation procedure, including an antral left and right pulmonary vein isolation with bidirectional bipolar clamping, and a roof and inferior line using unidirectional bipolar radiofrequency. Three procedural preventive mitigations were implemented: (1) transesophageal echocardiographic visualization of the atrio-esophageal interface, with probe retraction before the energy delivery; (2) lifting the ablated tissue away from the esophagus during an energy application; and (3) a 30 s cool-off and irrigation period after the energy delivery. The esophageal temperature was recorded using an insulated multisensory intraluminal esophageal temperature probe (Circa S-Cath™). Of the 20 patients enrolled, 7 patients had paroxysmal atrial fibrillation (AF), 8 persistent AF and 5 longstanding persistent AF. The average maximum luminal esophageal temperature observed was 36.2 ± 0.7 °C (34.8–38.2 °C). In our clinical experience, no abrupt increase in the luminal esophageal temperature above the baseline was observed. Since no measurements exceeded the threshold of 39 °C, no prompt interruption of energy delivery was required. Intraluminal esophageal temperature monitoring is feasible and can be helpful in confirming correct catheter position and safe energy application in bipolar epicardial left atrial ablation. Intra-procedural preventive mitigations should be implemented to reduce the risk of esophageal temperature rises. Full article

Objective: The objective of this study was to develop a new strategy for rapid diagnosis of the source of low back pain (LBP) for treatment with cooled radiofrequency ablation (RFA). Materials: Patients suffering from facet joint (FJ) or sacroiliac joint (SIJ) pain for more than 3 months were included. Two methods, Technetium Tc99m methylene diphosphonate single photon emission tomography/computed tomography (^99mTc-MDP SPECT/CT) and a modified Fortin finger test were used to identify the source of LBP for treatment with cooled RFA. The visual analog scale (VAS) and Oswestry disability index (ODI) were used to assess the patients’ pain levels and disabilities respectively. These two measures were recorded at baseline and 1-week, 1-month, 3-month, and 6-month follow-up visits. Results: A total of 40 patients with LBP were included in this study. Our results demonstrated that the patients with LBP identified by our new strategy had significant improvements in VAS or ODI score at 1-week to 6-month follow-up visits (p < 0.001) after receiving cooled RFA. Similar results were also found in patients with FJ pain and those with FJ and SIJ pain respectively. Among all the patients, over 70% had greater than or equal to 50% reduction in VAS and ODI scores. No serious adverse events were observed after treatment. Conclusions: This new strategy could be successfully adopted for rapid diagnosis of the source of comprehensive LBP. Full article

The objective of this study was to investigate the feasibility of a newly developed anticancer drug-releasing radiofrequency ablation (RFA) system in a porcine liver model. A 15-gauge drug-releasing cooled wet electrode (DRCWE) was newly developed to improve the RFA efficacy for creating a large ablation as well as for simultaneously delivering an anticancer drug to the tumor margin. Nine ablations in three pigs were performed by the DRCWE. The sectioned liver specimens were evaluated by measuring the ablation zone by a positron emission tomography/magnetic resonance imaging examination to investigate whether ¹⁸F-fluorodeoxyglucose was exactly diffused. Volumes of the ablation zones released drug injection volumes, circularity, retention rate defined as the ratio between an estimated and injection dose, and the standard uptake value were assessed. The drug-releasing RFA was technically successful without procedural-related complications. During the procedure, the color changes of the ablated zones of the liver were observed in all specimens. The mean drug injection volume was higher than the ablated volumes (17.21 ± 2.85 vs. 15.22 ± 2.30 cm³) and the circularity was 0.72 ± 0.08. Moreover, the retention rate was 72.89% ± 4.22% and the mean standard uptake value was 0.44 ± 0.05. The drug-releasing RFA system was feasible not only for local ablation but also for the delivery of anticancer drugs. The results of this study indicate that this novel strategy of localized RFA with a drug delivery system could be a promising option for the prevention of local recurrence rates. Full article

Radiofrequency ablation (RFA) was first introduced for treating knee osteoarthritis (OA) in 2010 and has emerged as a minimally invasive treatment option. Three RFA techniques have been adopted for treating knee OA, including conventional, pulsed, and cooled RFA. However, the efficacy among different RFA techniques in the treatment of knee OA is still unclear. Three electronic databases were systematically searched for relevant articles, including PubMed, Embase, and Cochrane Library. A meta-analysis of articles that investigated the use of RFA techniques in the treatment of knee OA was conducted to pool the effect size in pain before and after treatment. A total of 20 eligible articles (including 605 patients) were included for our meta-analysis. After treatment, the patients had significant improvements in pain for all three RFA techniques when compared with the baseline level for the 1, 3-, and 6-month follow-ups (p < 0.00001). However, there were no significant differences in the efficacy among the three RFA techniques for all follow-up visits (p > 0.05). The three RFA techniques demonstrated a significant improvement in pain for up to 6 months after treatment. Comparing the efficacy of the three RFA techniques in the treatment of knee OA, our results showed that no significant differences in pain relief among the three RFA techniques were observed at the 1-, 3-, 6, and 12-month follow-up visits. Full article

Superparamagnetic nanoparticles (iron oxide nanoparticles—IONs) are suitable for hyperthermia after irradiating with radiofrequency radiation. Concerning the suitability for laser ablation, IONs present a low molar absorption coefficient in the near-infrared region close to 800 nm. For this reason, they are combined with other photothermal agents into a hybrid composite. Here, we show that IONs absorb and convert into heat the infrared radiation characteristic of the so-called second-biological window (1000–1350 nm) and, in consequence, they can be used for thermal ablation in such wavelengths. To the known excellent water solubility, colloidal stability and biocompatibility exhibited by IONs, an outstanding photothermal performance must be added. For instance, a temperature increase of 36 °C was obtained after irradiating at 8.7 W cm⁻² for 10 min a suspension of IONs at iron concentration of 255 mg L⁻¹. The photothermal conversion efficiency was ~72%. Furthermore, IONs showed high thermogenic stability during the whole process of heating/cooling. To sum up, while the use of IONs in the first bio-window (700–950 nm) presents some concerns, they appear to be good photothermal agents in the second biological window. Full article