You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
Sustained Weight Loss with Vagal Nerve Blockade but Not with Sham: 18-Month Results of the ReCharge Trial
Abstract 1:
Background / Objectives . Vagal block therapy ( vBloc ) is effective for moderate to severe obesity at one year . Subjects/ Methods . The ReCharge trial is a double-blind , r and omized controlled clinical trial of 239 participants with body mass index ( BMI ) of 40 to 45 kg/m or 35 to 40 kg/m with one or more obesity-related conditions . Interventions were implantation of either vBloc or Sham devices and weight management counseling . Mixed models assessed percent excess weight loss ( % EWL ) and total weight loss ( % TWL ) in intent-to-treat analyses . At 18 months , 142 ( 88 % ) vBloc and 64 ( 83 % ) Sham patients remained enrolled in the study . Results . 18-month weight loss was 23 % EWL ( 8.8 % TWL ) for vBloc and 10 % EWL ( 3.8 % TWL ) for Sham ( P < 0.0001 ) . vBloc patients largely maintained 12-month weight loss of 26 % EWL ( 9.7 % TWL ) . Sham regained over 40 % of the 17 % EWL ( 6.4 % TWL ) by 18 months . Most weight regain preceded unblinding . Common adverse events of vBloc through 18 months were heartburn/dyspepsia and abdominal pain ; 98 % of events were reported as mild or moderate and 79 % had resolved . Conclusions . Weight loss with vBloc was sustained through 18 months , while Sham  regained weight between 12 and 18 months . vBloc is effective with a low rate of serious complications


Title 2:
Selection of electrical algorithms to treat obesity with intermittent vagal block using an implantable medical device.
Abstract 2:
BACKGROUND A laparoscopically implantable electrical device that intermittently blocks both vagi near the esophagogastric junction led to significant excess weight loss ( EWL ) in an initial clinical trial in obese patients . The study objective was to optimize therapy algorithms and determine the EWL achieved with a second-generation device at university hospitals in Australia , Norway , and Switzerl and . METHODS Data acquired during the initial clinical trial were analyzed and subsequently used to select alternative electrical algorithms . In the second trial , vagal blocking using one selected therapy algorithm was initiated 2 weeks after implanting the second-generation device . The patients were followed up for 6 months to assess the EWL and safety , including adverse events . RESULTS In the initial clinical trial , vagal blocking algorithm duration s of 90 - 150 s were associated with greater EWL compared with either shorter or longer algorithm duration s ( P<.01 ) . The second trial enrolled 27 patients ( mean body mass index 39.3+/-.8 kg/m2 ) to evaluate a 120-s blocking algorithm . At 6 months , greater EWL was achieved ( 22.7%+/-3.1 % , n=24 ) compared with the initial study and first-generation device ( 14.2%+/-2.2 % , n=29 , P=.03 ) . In both trials , an association was found between the number of 90 - 150-s algorithms delivered daily and greater EWL ( P=.03 ) . No deaths , unanticipated device-related adverse events , or medically serious adverse events were associated with the device . CONCLUSION This second-generation vagal blocking device , using a therapy algorithm of 120-s duration , result ed in a clinical ly acceptable safety profile and significantly greater EWL compared with the first-generation device delivering a wider range of therapy algorithm duration


Title 3:
Intra-abdominal vagal blocking (VBLOC therapy): clinical results with a new implantable medical device.
Abstract 3:
BACKGROUND A new medical device uses high-frequency electrical algorithms to create intermittent vagal blocking ( VBLOC therapy ) . The aim is to assess the effects of vagal blocking on excess weight loss ( EWL ) , safety , dietary intake , and vagal function . METHODS An open-label , 3-center study was conducted in obese subjects ( body mass index [ BMI ] 35 - 50 kg/m(2 ) ) .  Electrodes were implanted laparoscopically on both vagi near the esophagogastric junction to provide electrical block . Patients were followed for 6 months for body weight , safety , electrocardiogram , dietary intake , satiation , satiety , and plasma pancreatic polypeptide ( PP ) response to sham feeding . To specifically assess device effects alone , no diet or exercise programs were instituted . RESULTS Thirty-one patients ( mean BMI , 41.2 + /- 1.4 kg/m(2 ) ) received the device .  Mean EWL at 4 and 12 weeks and 6 months after implant was 7.5 % , 11.6 % , and 14.2 % , respectively ( all P < .001 ) ; 25 % of patients lost > 25 % EWL at 6 months ( maximum , 36.8 % ) . There were no deaths or device-related serious adverse events ( AEs ) . Calorie intake decreased by > 30 % at 4 and 12 weeks and 6 months ( all P < or= .01 ) , with earlier satiation ( P < .001 ) and reduced hunger ( P = .005 ) . After 12 weeks , plasma PP responses were suppressed ( 20 + /- 7 vs 42 + /- 19 pg/mL ) . Average percent EWL in patients with PP response < 25 pg/mL was double that with PP response > 25 pg/mL ( P = .02 ) . Three patients had serious AEs that required brief hospitalization , 1 each for lower respiratory tract , subcutaneous implant site seroma , and Clostridium difficile diarrhea . CONCLUSIONS Intermittent , intra-abdominal vagal blocking is associated with significant EWL and a desirable safety profile


Title 4:
Bladder voiding by combined high frequency electrical pudendal nerve block and sacral root stimulation.
Abstract 4:
AIMS Uncoordinated contraction of the external urethral sphincter is prevalent in individuals with spinal cord injury and can prevent bladder voiding . The aim of this study was to demonstrate that complete and reversible sinusoidal high frequency alternating current ( HFAC ) conduction block of the pudendal nerves ( PN ) can eliminate external urethral sphincter activation and produce low residual bladder voiding . METHODS In four cats , tripolar nerve cuff electrodes were implanted bilaterally on both pudendal nerves and on both extradural S2 roots . Bladder and urethral pressures , bladder volumes and flow were recorded . Bilateral HFAC was applied to determine voltage and frequency parameters result ing in bilateral PN conduction block . Sacral root stimulation provided bladder activation . R and omized sets of voiding trials were conducted with and without HFAC PN block . Additional voiding trials were conducted following bilateral PN neurotomy to eliminate somatic sphincter resistance and provide an estimate of voiding with complete block . RESULTS Effective bilateral PN block and voiding was obtained in three of four animals . Application of bilateral PN HFAC stimulation improved voiding from 2 + /- 4 % to 77 + /- 18 % of the initial bladder volume and significantly ( P < 0.001 ) reduced maximum bladder pressure during voiding . Voiding in trials with PN block was not significantly different from voiding following PN neurotomy ( 82 + /- 19 % , P = 0.51 ) . CONCLUSIONS These results demonstrate that bilateral HFAC block of the PN can produce effective voiding . Neural prostheses using this approach may provide an alternative method for producing micturition for people with spinal cord injury


Title 5:
Effect of Unmodulated 5-kHz Alternating Currents Versus Transcutaneous Electrical Nerve Stimulation on Mechanical and Thermal Pain, Tactile Threshold, and Peripheral Nerve Conduction: A Double-Blind, Placebo-Controlled Crossover Trial.
Abstract 5:
OBJECTIVE To investigate the effect of unmodulated 5-kHz alternating current on mechanical pain threshold ( MPT ) , heat pain threshold ( HPT ) , tactile threshold ( TT ) , and peripheral nerve conduction ( PNC ) compared with transcutaneous electrical nerve stimulation ( TENS ) and sham stimulation . SETTING National referral center . DESIGN R and omized , double-blind , placebo-controlled crossover trial . PARTICIPANTS Healthy volunteers ( N=38 ) . No dropouts or adverse events were reported . INTERVENTION TENS , unmodulated 5-kHz currents , and sham stimulation were applied on the radial nerve for 20 minutes with a 24-hour washout period between them and concealed intervention allocation . MAIN OUTCOME MEASURES Four measures were taken : before , during , and 2 after the interventions . Algometry was used to assess MPT , a Peltier thermode for HPT using the method of limits , Von Frey filaments for TT , and radial nerve compound action potential . RESULTS No differences were observed on MPT , HPT , and PNC when 5-kHz current and TENS were compared . However , TT increased 56.2mN ( 95 % confidence interval [ CI ] , 28.8 - 83.6 ) in the TENS group compared with the 5-kHz current group during intervention . Compared with sham stimulation during intervention , MPT increased 4.7N ( 95 % CI , 0.3 - 9.2 ) using 5-kHz current and 10.4N ( 95 % CI , 3.5 - 17.3 ) with TENS . TT increased 17.2mN ( 95 % CI , 4.7 - 29.7 ) with 5-kHz current and 73.4mN ( 95 % CI , 47.5 - 99.2 ) with TENS . However , HPT increased 1.0 ° C ( 95 % CI , 0.2 - 2.0 ) only with TENS . For the PNC , no differences were found among the 3 groups . CONCLUSIONS Unmodulated 5-kHz current produced an increase in somatosensory thresholds that was greater than placebo but not when compared with TENS ; however , participants perceived 5-kHz currents to be more comfortable and showed more habituation to them


Title 6:
The EMPOWER Study: Randomized, Prospective, Double-Blind, Multicenter Trial of Vagal Blockade to Induce Weight Loss in Morbid Obesity
Abstract 6:
Background Intermittent , reversible intraabdominal vagal blockade ( VBLOC ® Therapy ) demonstrated clinical ly important weight loss in feasibility trials . EMPOWER , a r and omized , double-blind , prospect i ve , controlled trial was conducted in USA and Australia . Methods Five hundred three subjects were enrolled at 15 centers . After informed consent , 294 subjects were implanted with the vagal blocking system and r and omized to the treated ( n = 192 ) or control ( n = 102 ) group . Main outcome measures were percent excess weight loss ( percent EWL ) at 12 months and serious adverse events . Subjects controlled duration of therapy using an external power source ; therapy involved a programmed algorithm of electrical energy delivered to the subdiaphragmatic vagal nerves to inhibit afferent/efferent vagal transmission . Devices in both groups performed regular , low-energy safety checks . Data are mean ± SEM . Results Study subjects consisted of 90 % females , body mass index of 41 ± 1 kg/m2 , and age of 46 ± 1 years . Device-related complications occurred in 3 % of subjects . There was no mortality . 12-month percent EWL was 17 ± 2 % for the treated and 16 ± 2 % for the control group . Weight loss was related linearly to hours of device use ; treated and controls with ≥12 h/day use achieved 30 ± 4 and 22 ± 8 % EWL , respectively . Conclusions VBLOC ® therapy to treat morbid obesity was safe , but weight loss was not greater in treated compared to controls ; clinical ly important weight loss , however , was related to hours of device use . Post- study analysis suggested that the system electrical safety checks ( low charge delivered via the system for electrical impedance , safety , and diagnostic checks ) may have contributed to weight loss in the control group
High-frequency alternating currents using frequencies of > 4–5 kHz effectively block nerve conduction .
There is no consensus about the block mechanism , although it has been showed that the frequency is a key factor to produce K+ channels activation or Na+ channels inactivation .
The nerve block produced by currents quickly reverts without causing further damage to the nerve .