*4.2.1.2 Efficacy and safety profile*

*Recent Advances in Laparoscopic Surgery*

*4.1.1.2 Efficacy and safety profile*

**4.2 Gastric electrical stimulation**

*4.2.1 The transcend implantable gastric stimulator*

Stimulator (IGS, Transneuronix Inc., Mt Arlington, NJ, USA).

allow the gastric tissue to heal before stimulation is initiated.

The maestro rechargeable system is an FDA approved implant device that is implanted with minimally invasive laparoscopic techniques. The system is provided with two leads which are placed around both the anterior and posterior vagal trunks at the level of the esophageal junction. Each lead delivers high-frequency, low energy, intermittent electrical pulses to its respective intra-abdominal vagal trunk for a predetermined period each day. This intermittent interruption of vagus nerve signaling leads to delayed gastric emptying which reduces feelings of hunger and promotes satiety [44]. A rechargeable neuroregulator is placed subcutaneously on the thoracic wall.

Several feasibility studies have shown that VBloc therapy has a desirable safety profile and results in clinically important weight loss [45]. However, in the first randomized controlled trial comparing VBloc therapy with sham control, results were disappointing [46]. VBloc therapy was regarded safe, but weight loss was no greater in treated compared to control patients. Authors reported that the system electrical safety checks could have accounted for the weight loss in the control group. Another randomized controlled trial demonstrated 24.4% EWL in the VBloc group compared to 15.9% in the sham control group after a period of 12 months [47]. An open label follow-up study of the VBloc arm showed maintenance of weight loss in the majority of patients [48]. Adverse events were more frequently reported in the VBloc group and mostly involved heartburn or dyspepsia. Stronger evidence is

needed to determine the place of VBloc therapy in the treatment of obesity.

Based on growing knowledge about gastrointestinal physiology, gastric electrical stimulation (GES) has been identified as a potential treatment modality for obesity [49, 50]. As early as 1995, the concept of GES was demonstrated in a series of animal experiments [51]. The exact mechanism of action of GES is still relatively unknown. However, it is thought that GES impairs gastric electrical activity, induces gastric distension, reduces gastric accommodation, and inhibits stomach peristalsis, thereby leading to delayed gastric emptying and increased satiety [52].

A novel gastric electrical stimulator is the Transcend Implantable Gastric

The device consists of one lead with two electrodes which is laparoscopically implanted on the lesser curvature near the pes anserinus and approximately 6 cm away from the pylorus. Proximally, the lead is fixed using an endostitch suture, and distally fixation is secured with the use of two clips. One electrode is positioned near the pes anserinus, while the other is placed near the esophagogastric junction. After adequate lead and electrode placement, the electrical pulse generator, which is connected to the lead, is implanted in a supra-fascial pocket and anchored with two sutures. Intraoperative gastroscopy is used to diagnose iatrogenic gastric perforation. After implantation, the device will be in off-mode for a period of 30 days, to

*4.1.1.1 Technique*

**46**

*4.2.1.1 Technique*

A safety and feasibility study of the Transcend IGS implanted in 12 patients demonstrated a technically feasible and safe procedure [53]. In 25% of the patients, lead dislodgement occurred which required replacement. After 9 months, patients had lost a mean weight of 16 ± 12 kg. Another study conducted in 2002, in which 20 patients with a mean BMI of 40.9 kg/m<sup>2</sup> received the device, showed a % EWL of 10.6 ± 1.8 at 1 month, 1.5 ± 3.5 at 6 months, and 23.8 ± 5.0 at 10 months. Three intraoperative gastric penetrations were observed by gastroscopy. No further adverse events or complications were reported during the study period [54]. However, in a prospective double-blinded randomized sham-controlled trial, no difference was observed between the treatment and control group after a treatment period of 12 months [55]. Contributing to this was an investigator-initiated substudy designed to assess whether IGS affects plasma levels of ghrelin and peptide YY which resulted in the conclusion that IGS does not prevent increase in fasting plasma levels of ghrelin that are associated with weight loss [56]. In conclusion, further studies are needed to determine whether changes in technology can provide meaningful weight loss and maintenance.
