Triple neurectomía transperitoneal laparoscópica y con asistencia robótica para el tratamiento del dolor inguinal crónico: descripción de la técnica, nuestra experiencia y resultados preliminares / Robot-assisted laparoscopic triple neurectomy for chronic inguinal pain: Description of the technique, our experience and preliminary results

Introducción. El dolor inguinal crónico o inguinodinia posthernioplastia es una complicación relativamente común y que puede llegar a ser muy incapacitante. El tratamiento quirúrgico mediante triple neurectomía es una opción terapéutica ante el fracaso de tratamientos previos (terapia oral, local o neuromodulación).ObjetivoDescripción retrospectiva de la técnica quirúrgica y resultados de la triple neurectomía laparoscópica y con asistencia robótica en el tratamiento de la inguinodinia crónica.Material y métodosSe describen los criterios de inclusión/exclusión, así como la técnica quirúrgica empleada en 7 pacientes intervenidos en el Complejo Asistencial Universitario de León (Servicio de Urología) tras no responder a otras alternativas terapéuticas.ResultadosLos pacientes presentaban dolor crónico inguinal reportando una valoración en la escala EVA del dolor prequirúrgica de 7,43 sobre 10. Tras la cirugía, dicha valoración se redujo a 3,71 al primer día postoperatorio y a 4,2 puntos al año de la intervención. El alta hospitalaria se produjo a las 24h de la cirugía y no se reportaron complicaciones relevantes.ConclusionesLa triple neurectomía laparoscópica o con asistencia robótica es una técnica segura, reproducible y eficaz en el tratamiento del dolor inguinal crónico refractario a otros tratamientos. (AU)

Introduction. Chronic inguinal pain or inguinodynia following hernioplasty is a relatively common complication that can be very incapacitating. Surgical treatment by triple neurectomy is a therapeutic option when previous treatments (oral/local therapy or neuromodulation) have failed.ObjectiveRetrospective description of the surgical technique and results of laparoscopic and robot-assisted triple neurectomy for chronic inguinodynia.Material and methodsWe describe the inclusion/exclusion criteria as well as the surgical technique applied in 7 patients operated on at the University Health Care Complex of León (Urology Department) after failure of other treatment options.ResultsThe patients presented chronic groin pain, reporting a preoperative pain VAS of 7.43 out of 10. After surgery, this score was reduced to 3.71 on the first postoperative day and to 4.2 points one year after surgery. Hospital discharge occurred 24hours after surgery with no relevant complications being reported.ConclusionsLaparoscopic or robot-assisted triple neurectomy is a safe, reproducible, and effective technique for the treatment of chronic groin pain refractory to other treatments. (AU)

Pulmonary Artery Denervation for Patients With Residual Pulmonary Hypertension After Pulmonary Endarterectomy.

BACKGROUND: Pulmonary artery denervation (PADN) procedure has not been applied to patients with residual chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary endarterectomy (PEA). OBJECTIVES: This study sought to assess the safety and efficacy of PADN using remote magnetic navigation in patients with residual CTEPH after PEA. METHODS: Fifty patients with residual CTEPH despite medical therapy at least 6 months after PEA, who had mean pulmonary artery pressure ≥25 mm Hg or pulmonary vascular resistance (PVR) > 400 dyn‧s‧cm-5 based on right heart catheterization were randomized to treatment with PADN (PADN group; n = 25) using remote magnetic navigation for ablation or medical therapy with riociguat (MED group; n = 25). In the MED group, a sham procedure with mapping but no ablation was performed. The primary endpoint was PVR at 12 months after randomization. Key secondary endpoint included 6-min walk test. RESULTS: After PADN procedure, 2 patients (1 in each group) developed groin hematoma that resolved without any consequences. At 12 months, mean PVR reduction was 258 ± 135 dyn‧s‧cm-5 in the PADN group versus 149 ± 73 dyn‧s‧cm-5 in the MED group, mean between-group difference was 109 dyn‧s‧cm-5 (95% confidence interval: 45 to 171; p = 0.001). The 6-min walk test distance was significantly increased in the PADN group as compared to distance in the MED group (470 ± 84 m vs. 399 ± 116 m, respectively; p = 0.03). CONCLUSIONS: PADN in patients with residual CTEPH resulted in substantial reduction of PVR at 12 months of follow-up, accompanied by improved 6-min walk test.

Randomized Pragmatic Pilot Trial Comparing Perpendicular Thin Electrode Versus Parallel Thick Electrode Approaches for Lumbar Medial Branch Neurotomy in Facetogenic Low Back Pain.

OBJECTIVES: Although there are different ways of performing medial branch neurotomy on facetogenic low back pain, few studies have compared clinical outcomes of a parallel technique over the medial branch vs. a perpendicular technique. We investigated differences in pain outcome with both techniques. DESIGN: This was a prospective, pilot, randomized, pragmatic trial (double blinded in the diagnostic phase). SETTING: A comparative pilot trial was conducted at an academic pain center. METHODS: Patients who did not respond to conservative medications and had severe lumbar pain for more than 3 months (VAS score ≥ 65) were included. A double diagnostic block with local anesthetic and placebo was performed, double blinded. Patients who had 80% relief from the local anesthetic and no substantial relief from placebo were randomized to undergo medial branch neurotomy under fluoroscopy, placing an electrode parallel or perpendicular to the medial branch. The primary outcome was differences in the VAS score at 1, 3, and 6 months. The secondary outcomes were Oswestry Disability Index score, Roland Morris Questionnaire score, and other functional Likert scale scores. RESULTS: Forty-three consecutive patients were randomized to parallel (n = 20) or perpendicular (n = 23) neurotomy. There were no significant differences in VAS, Oswestry Disability Index, or Roland Morris Questionnaire scores at 1, 3, or 6 months between groups. Statistically significant differences were found in the categorical analysis at 6 months in the evolution of pain, Oswestry Disability Index score, Roland Morris Questionnaire score, and some Likert scale scores in favor of the parallel group. CONCLUSIONS: There were differences at 6 months in the categorical analysis of the evolution of pain, Oswestry Disability Index score, Roland Morris Questionnaire score, and some functional Likert scale scores, all in favor of the parallel group.

Design for a multicenter, randomized, sham-controlled study to evaluate safety and efficacy after treatment with the Nuvaira® lung denervation system in subjects with chronic obstructive pulmonary disease (AIRFLOW-3).

BACKGROUND: Targeted lung denervation (TLD) is a bronchoscopically delivered ablation therapy that selectively interrupts pulmonary parasympathetic nerve signaling. The procedure has the potential to alter airway smooth muscle tone and reactivity, decrease mucous secretion, and reduce airway inflammation and reflex airway hyperresponsiveness. Secondary outcome analysis of a previous randomized, sham-controlled trial showed a reduction in moderate-to-severe exacerbations in patients with COPD after TLD treatment. A pivotal trial, AIRFLOW-3 has been designed to evaluate the safety and efficacy of TLD combined with optimal medical therapy to reduce moderate or severe exacerbations throughout 1 year, compared with optimal medical therapy alone. METHODS: The study design is a multicenter, randomized, full sham bronchoscopy controlled, double-blind trial that will enroll 400 patients (1:1 randomization). Key inclusion criteria are FEV1/FVC < 0.7, FEV1 30 to 60% of predicted, post-bronchodilator, ≥ 2 moderate or 1 severe COPD exacerbations in the prior year, and COPD assessment test (CAT) ≥ 10. Primary objective will be the comparison of moderate or severe COPD exacerbations through 12 months of TLD therapy with optimal medical therapy versus optimal medical therapy alone. The sham group will be allowed to cross over at 1 year. Patients will be followed for up to 5 years. DISCUSSION: The multicenter, randomized, full sham bronchoscopy controlled, double-blind AIRFLOW-3 trial will evaluate the efficacy of TLD to reduce moderate or severe COPD exacerbations beyond optimal medical therapy alone. The target population are patients with COPD, who suffer persistent symptoms and exacerbations despite optimal treatment, defining an unmet medical need requiring novel therapeutic solutions. This trial is registered at clinicaltrials.gov: NCT03639051.

Initial Evaluation of a Novel Modulated Radiofrequency-based Bladder Denervation Device.

OBJECTIVE: To determine if targeted and modulated radiofrequency ablation (RFA) of the urinary bladder using our novel ablation device (Denerblate) reduces bladder nerve density, potentially leading to a novel strategy for the management of overactive bladder. METHODS: Fifteen pigs were divided into 4 groups: control (n = 3), 1-week (n = 4), 4-week (n = 4) and 12-week (n = 4) survival times. Denerblate was deployed on the trigone area of the bladder. Three 240-second cycles of modulated RFA were applied with 30 seconds between cycles. At the end of each survival term, urinary bladders were harvested for histopathologic evaluation. Nerve count and density were manually calculated. RESULTS: All procedures were successfully completed, and all animals survived to the desired time points. Mean nerve density (nerves/mm2) was highest in the control and 1-week survival group compared to the 4-week and 12-week groups, both of which demonstrated significant diminishment. Nerve density in the bladder neck at control, 1 week, 4 weeks, and 12 weeks were 1.8, 1.35, 0.87, and 0.12, respectively (P <.001). Nerve density in the bladder trigone area at control, 1 week, 4 weeks, and 12 weeks were 1.5, 0.98, 0.65, and 0.112, respectively (P <.001). Epithelial heat injury was observed in 14.3% at 1 week, 10.7% at 4 weeks, but completely resolved by 12 weeks. CONCLUSION: In the porcine model, modulated RFA delivered by our novel device reduced nerve density in the bladder neck and trigone by 88.6% and 88.9% at 12 weeks without evidence of lasting epithelial injury.

Experiencia inicial con catéter multielectrodo en denervación renal. ¿Una técnica que ha vuelto para quedarse? / Initial experience with a multi-electrode catheter in renal denervation. A technique that has come back to stay?

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Safety and efficacy of endovascular ultrasound renal denervation in resistant hypertension: 12-month results from the ACHIEVE study.

OBJECTIVES: First-generation radiofrequency renal denervation devices may have had limited efficacy due to incomplete circumferential ablation and dependence on individual operator technique. This study evaluated a next-generation catheter-based technology using ultrasound designed to maximize nerve coverage using circumferential ultrasound energy. METHODS: This was a prospective, multicenter, nonrandomized, postmarket study evaluating the safety and efficacy of an endovascular ultrasound renal denervation system (Paradise) in patients who met the European Society of Hypertension/European Society of Cardiology definition of resistant hypertension. Major exclusion criteria included renal artery stenosis and renal insufficiency. Patients were followed for 12 months. Safety and efficacy endpoints included procedural safety and renal artery patency, as well as changes in systolic office and 24-h ambulatory bllod pressure (BP) measurement. RESULTS: A total of 96 patients from eight European sites were included. Mean age was 63.9 years and 41% of patients were female. At baseline, mean 24-h ambulatory BP was 156.2/88.4 ±â€Š15.4/12.7 mmHg, and mean office BP was 176.2/95.0 ±â€Š20.6/16.0 mmHg. Patients were on average on 5.1 ±â€Š2.5 antihypertensive agents. At 12 months, the average 24-h ambulatory BP change was -7.5/-3.8 ±â€Š18.3/10.6 mmHg (P = 0.0007; P = 0.0024) with an average office BP change of -15.0/-7.0 ±â€Š27.0/12.3 mmHg (P < 0.0001 for both). At 12 months, there was a single patient death unrelated to the device or procedure. CONCLUSION: This single-arm study represents the largest cohort of patients treated with endovascular ultrasound renal denervation to date. Within this trial, the therapy appeared safe and resulted in sustained reductions in both office BP and 24-h ambulatory BP through 12 months.

The Effects of Radiofrequency Neurotomy Using a Strip-Lesioning Device on Patients with Sacroiliac Joint Pain: Results from a Single-Center, Randomized, Sham-Controlled Trial.

BACKGROUND: Radiofrequency neurotomy (RFN) is a therapy aimed at providing lasting back pain relief for sacroiliac joint (SIJ) pain. A recent advancement in RFN is a strip lesioning technique that involves placement of a single curved electrode and a 3-pole design that facilitates the creation of 5 overlapping lesions. These lesions form one long strip lesion accessible through a single entry point, without the need for multiple punctures. Although the early case series data looks promising, there is lack of long-term, randomized, controlled study evaluating the strip-lesioning system for SIJ pain. OBJECTIVES: The purpose of this study was to examine the safety and effectiveness of RFN using a strip lesioning device for reduction of SIJ pain. STUDY DESIGN: Prospective, double-blind, randomized, sham-controlled trial with 6-month follow-upSETTING: A tertiary care interventional pain management center in the UK METHODS: Patients with SIJ pain with positive diagnostic local anesthetic blocks were randomly assigned (2:1) to either the sham (no RF lesions performed) or the active group (RF lesions performed). The primary endpoint was improvement of pain using the Numeric Rating Scale (NRS-11) at 3 months. Results were analyzed using nonparametric tests. Safety, secondary, and long-term outcome data were also collected. RESULTS: Seventeen of 30 enrolled patients were randomly assigned to active treatment (n = 11) or sham treatment (n = 6). At 3 months, the mean NRS-11 score for the active group had decreased significantly, from 8.1 (± 0.8) at baseline to 3.4 (± 2.0) (P < 0.001). The sham group did not experience a statistically or clinically meaningful decrease in mean NRS-11 score from baseline (7.3 ± 0.8) to 3 months (7.0 ± 1.7). On average, patients in the active group moved from borderline anxiety at baseline (9.4 ± 5.9) to no anxiety (6.6 ± 6.3) at 3 months. Results were similar at 6 months. LIMITATIONS: Recruitment was stopped at 30 enrolled patients, only 17 of whom were randomly assigned to active or sham treatment, after the interim analysis indicated a statistically significant (P < 0.001) difference in the pain outcome between the treatment and the sham groups. CONCLUSIONS: This study demonstrated that radiofrequency neurotomy using a strip lesioning device is an appropriate therapy to treat SIJ pain. KEY WORDS: Radiofrequency, sacroiliac joint pain, low back pain, neurotomy, randomized controlled trial, simplicity.

Effects of Multi-Electrode Renal Denervation on Insulin Sensitivity and Glucose Metabolism in a Canine Model of Type 2 Diabetes Mellitus.

PURPOSE: To evaluate the effects of multi-electrode catheter-based renal denervation (RDN) on insulin sensitivity and glucose metabolism in a type 2 diabetes mellitus (T2DM) canine model. MATERIALS AND METHODS: Thirty-three dogs were divided equally into 3 groups: bilateral renal denervation (BRDN) group, left renal denervation (LRDN) group, and sham operation (SHAM) group. Body weight and blood biochemistry were measured at baseline, 20 weeks, and 32 weeks, and renal angiography and computerized tomographic (CT) angiography were determined before the procedure and 1 month, 2 months, and 3 months after the procedure. Western blot was used to identify the activities of gluconeogenic enzymes and insulin-signaling proteins. RESULTS: Fasting plasma glucose (9.64 ± 1.57 mmol/L vs 5.12 ± 1.08 mmol/L; P < .0001), fasting insulin (16.19 ± 1.43 mIU/mL vs 5.07 ± 1.13 mIU/mL; P < .0001), and homeostasis-model assessment of insulin resistance (HOMA-IR; 6.95 ± 1.33 vs 1.15 ± 0.33; P < .0001) in the BRDN group had significantly decreased at the 3-month follow-up compared with the SHAM group. Western blot analyses showed that RDN suppressed the gluconeogenetic genes, modulated insulin action, and activated insulin receptors-AKT signaling cascade in the liver. CT angiography and histopathologic analyses did not show any dissection, aneurysm, thrombus, or rupture in any of the renal arteries. CONCLUSIONS: These findings identified that multi-electrode catheter-based RDN could effectively decrease gluconeogenesis and glycogenolysis, resulting in improvements in insulin sensitivity and glucose metabolism in a T2DM canine model.

Clinical Efficacy Evaluation for Treating Trigeminal Neuralgia Using a Personalized Digital Guide Plate-Assisted Temperature-Controlled Radiofrequency.

The aim of this study was to explore the application and efficacy of personalized digital guiding plate-aided radiofrequency in treating trigeminal neuralgia (TN). A total of 117 cases (93 patients) of TN from January 2015 to December 2016 were divided into the study group (n = 53) and the traditional group (n = 64). Patients in the study group were treated by the radiofrequency through a personalized digital guiding plate, whereas those in the traditional group were treated by the traditional method. We found that no significant difference between these 2 groups in age, sex, and divisions affected (V2, V3). However, the values for operation time, recurrence rate, and patient's satisfaction in the plate assisted group were significantly improved compared with those in the traditional group. Therefore, the personalized digital guiding plate-assisted radiofrequency has higher application value than traditional method.

Radiofrequency Denervation of the Cervical and Lumbar Spine.

Facet or zygapophysial joint pain is commonly seen in the aging population. Interventional procedures, such as facet joint nerve blocks, facet intraarticular injections, and radiofrequency denervation, are used for the diagnosis and treatment of axial spinal chronic neck and low back pain. The focus of this article is to understand how radiofrequency denervation works in the cervical and lumbar spine and to be able to properly select appropriate patients who might benefit from this safe and effective procedure.

Conventional (Simplicity III) and Cooled (SInergy) Radiofrequency for Sacroiliac Joint Denervation: One-Year Retrospective Study Comparing Two Devices.

OBJECTIVE: To compare two radiofrequency (RF) devices, Simplicity III (conventional RF), and SInergy (cooled RF), which are specifically designed to denervate the sacroiliac joint (SIJ). DESIGN: Retrospective observational study. SETTING: Italian National Health Service Public Hospital. SUBJECTS: Forty-three patients with SIJ-derived pain refractory to conservative treatment; 21 and 22 patients, respectively, received Simplicity III or SInergy to denervate the SIJ. METHODS: Mean numerical rating scale (NRS) and Oswestry Disability Index (ODI) scores were determined for each study group up to 12 months postprocedure. Secondary outcomes included the average amount of time required to complete each RF procedure and the adverse events associated with each technique. RESULTS: Average SInergy group NRS and ODI scores were consistently less than those in the Simplicity III cohort at each post-RF denervation follow-up, and such differences were statistically significant at six and 12 months. The Simplicity III procedure was completed approximately 2.5 times faster than the SInergy procedure, and one minor adverse event was reported in the SInergy group. CONCLUSIONS: The study results suggest that SInergy safely afforded patients with greater and more durable analgesia and disability relief than Simplicity III for SIJ-derived pain. The Simplicity III procedure may be more conducive than SInergy for bilateral procedures and for patients who have limited tolerance to be in an RF procedure-required prone position. Randomized controlled trials are needed to confirm the implication made in this study that SInergy is the preferred RF denervation option for treating SIJ-derived pain and the disability associated with it.

Surgical Denervation in the Imiquimod-Induced Psoriasiform Mouse Model.

Psoriasis is a chronic inflammatory skin disease with a prevalence of 2-3 %. It appears to result from a combination of genetic and environmental factors, but the precise pathogenesis is still unknown. Neurogenic inflammation is involved in psoriasis pathogenesis as well, but the role of neurogenic factors is currently unclear. Molecular studies often involve material obtained from patients. However, many questions and especially experimental manipulations are not suited for study in humans. Imiquimod application on mouse skin leads to immune cell infiltration, inflammation with intense redness, epidermal thickening, and scaling that jointly greatly resembles human psoriasis. Here we describe the use of surgical denervation in the imiquimod-induced psoriasiform model, to study the role of skin innervation and neuropeptides in the pathogenesis of psoriasis.

Analysis of equivalent parameters of two spinal cord injury devices: the New York University impactor versus the Infinite Horizon impactor.

BACKGROUND CONTEXT: The New York University (NYU) impactor and the Infinite Horizon (IH) impactor are used to create spinal cord injury (SCI) models. However, the parameters of these two devices that yield equivalent SCI severity remain unclear. PURPOSE: To identify equivalent parameters, rats with SCIs induced by either device set at various parameters were subjected to behavioral and histologic analyses. STUDY DESIGN: This is an animal laboratory study. METHODS: Groups of eight rats acquired SCIs by dropping a 10 g rod from a height of 25 mm or 50 mm by using the NYU device or by delivering a force of 150 kdyn, 175 kdyn, 200 kdyn, or 250 kdyn by using the IH impactor. All injured rats were tested weekly for 8 weeks by using the Basso, Beattie, and Bresnahan (BBB) test and the ladder rung test. On the 10th week, the lesion volume of each group was measured by using a 9.4 Tesla magnetic resonance imaging (MRI), and the spinal cords were subjected to histologic analysis using anterograde biotinylated dextran amine (BDA) tracing and immunofluorescence staining with an anti-protein kinase C-gamma (PKC-γ) antibody. RESULTS: Basso, Beattie, and Bresnahan test scores between the 25 mm and the 200 kdyn groups as well as between the 50 mm and and 250 kdyn groups were very similar. Although it was not statistically significant, the mean scores of the ladder rung test in the 200 kdyn group were higher than the 25 mm group at all assessment time points. There was a significantly different cavity volume only between the 50 mm and the 200 kdyn groups. Midline sagittal images of the spinal cord on the MRI revealed that the 25 mm group predominantly had dorsal injuries, whereas the 200 kdyn group had deeper injuries. Anterograde tracing with BDA showed that in the 200 kdyn group, the dorsal corticospinal tract of the caudal area of the lesion was labeled. Similar labeling was not observed in the 25 mm group. Immunofluorescence staining of PKC-γ also revealed strong staining of the dorsal corticospinal tract in the 200 kdyn group but not in the 25 mm group. CONCLUSIONS: The 25 mm injuries generated by the NYU impactor are generally equivalent to the 200 kdyn injuries generated by using the IH impactor. However, differences in the ladder rung test scores, MRI images, BDA traces, and PKC-γ staining demonstrate that the two devices exert qualitatively different impacts on the spinal cord.

Non-invasive Renal Denervation: Update on External Ultrasound Approaches.

In the last decade, intravenous renal denervation (RDN) has emerged as an alternative to pharmacological treatment in patients with resistant hypertension, but currently involves an invasive and technically challenging procedure. The Surround Sound™ system utilises externally delivered ultrasound to achieve RDN using a completely non-invasive, automated real-time tracking system coupled with a therapeutic delivery module thereby addressing these limitations. A brief history, technical overview and summary of preclinical and clinical studies of the KonaMedical Surround Sound™ system are presented. A literature search using the terms "renal denervation", "resistant hypertension" and "external ultrasound" was performed using PubMed, and references retrieved were selected based on relevancy and year of publication (date range 1991-2015). The Surround Sound™ system appears to be a promising approach to RDN which eliminates several of the factors currently limiting the intravenous approach. So far, it has demonstrated efficacy for reducing blood pressure in resistant hypertension patients with minimal adverse effects. Several double-blind, sham-controlled clinical trials are currently underway to confirm the validity of these findings.

Low Pain Catastrophization and Disability Predict Successful Outcome to Radiofrequency Neurotomy in Individuals with Chronic Whiplash.

OBJECTIVES: Physical and psychological symptoms of individuals with chronic whiplash-associated disorders (WAD) are modulated by successful treatment with cervical radiofrequency neurotomy (cRFN). However, not all individuals respond to cRFN, and it is unknown which clinical features predict successful response to cRFN. METHODS: This prospective cohort study investigated 53 individuals with chronic WAD (36 female, 17 male; mean age = 44.7 ± 10.9 (SD) years) who underwent cRFN. Predictor variables measured at baseline (prior to RFN) included self-reported pain (VAS), disability (NDI), post-traumatic stress symptoms (PDS), pain catastrophizing (PCS), and measures of sensory hypersensitivity (pressure and cold pain thresholds). The outcome measure was perceived Global Rating of Change (where scores ≥ 4 were classified as a successful response) 3 months post-cRFN. RESULTS: Univariate logistic regression demonstrated that lower levels of disability and pain catastrophizing were associated with successful response of cRFN (both P < 0.05). Multivariable logistic regression demonstrated that low levels of pain catastrophizing and disability remained significant predictors of a successful response to cRFN (both P < 0.05). CONCLUSIONS: Low levels of pain catastrophizing and disability independently predicted a successful response to cRFN in patients with chronic WAD.

Comparison of Saline-Irrigated Catheter vs. Temperature-Controlled Catheter for Renal Denervation in a Canine Model.

BACKGROUND: The effectiveness of catheter-based renal denervation (RDN) remains controversial. Although the reasons for this have not yet been elucidated, ineffective denervation appears to be an important factor. The present study aimed to investigate the difference in RDN between a saline-irrigated catheter (SIC) and a temperature-controlled catheter (TCC). METHODS: Dogs (n = 6) from the Kunming province in Chinese were ablated; the SIC was introduced into the right renal artery, while the TCC was introduced into the left renal artery. After 6 months, histopathology and renal angiography were performed, and the change in neural density was evaluated using morphometric software. The average values of heart rate (HR), blood pressure (BP), and catecholamine metabolites were assessed at baseline and follow-up. RESULTS: Histopathology showed nerve demyelination and denaturation, as well as interstitial hyperplasia, although these changes were more pronounced when the SIC was used. The change in neural density was greater and ablation was deeper when the SIC was used. Intimal hyperplasia was greater when the TCC was used, whereas medial hyperplasia was greater when the SIC was used. A trend toward a decrease in HR, BP, metanephrine, and normetanephrine between baseline and follow-up was observed. CONCLUSIONS: Our findings suggest that SIC ablation results in more extensive neural degeneration, deeper penetration, and less extensive intimal hyperplasia than TCC ablation for RDN.

Renal denervation using focused infrared fiber lasers: a potential treatment for hypertension.

BACKGROUND AND OBJECTIVE: Renal denervation has recently become of great interest as a potential treatment for resistant hypertension. Denervation techniques using radio frequency (RF) or ultrasound energy sources have already been explored in literature. In this study, we investigate the use of lasers as a potential energy source for renal denervation. In vitro studies are performed in porcine/ovine renal arteries with focused laser beams at 980 nm, 1210 nm, and 1700 nm to study the ability to damage renal nerves without causing injury to non-target tissue structures like the endothelium. Then, a 980 nm laser catheter prototype is built and used to demonstrate in vivo renal denervation in ovine renal arteries. SUBJECTS AND METHODS: This study utilizes fiber coupled infrared lasers at 980 nm, 1210 nm, and 1700 nm. In vitro laser denervation studies at 980 nm are performed in both porcine and ovine renal arteries to study the ability of focused laser beams to damage renal nerves without injuring the endothelium. In vitro studies using lasers close to the lipid absorption lines at 1210 nm and 1700 nm are also performed in porcine renal arteries to study the possibility of selectively damaging the renal nerves by targeting the lipid myelin sheaths surrounding the nerves. Then, a laser catheter prototype is designed and built for in vivo renal denervation in ovine renal arteries using the 980 nm laser (powers ranging from 2 to 4 W, 5 seconds per exposure). Histochemical evaluations of the frozen sections are performed using methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. RESULTS: Histochemical analysis of in vitro laser treatments at 980 nm in porcine and ovine renal arteries show clear evidence of laser-induced renal nerve damage without injury to the endothelium and part of the media. No evidence of selective nerve damage is observed using the 1210 nm and 1700 nm lasers with the current treatment parameters. Histochemical analysis of in vivo laser treatments in ovine renal arteries using a focused 980 nm laser show clear evidence of renal nerve damage with depths of damage extending > 1.5 mm from the artery wall. Sections with laser-induced damage to the media/adventitia at depths of > 1 mm without injury to the endothelium are also observed. CONCLUSIONS: We demonstrate the use of focused lasers as an attractive energy source for causing renal nerve damage without injury to the artery wall and thus, may have potential therapeutic applications for conditions such as resistant hypertension, where renal denervation has been shown to be a promising form of treatment.