Background: Autonomic and vagal neuromodulation has been suggested for the treatment of morbid obesity. Occipital nerves remain in close anatomical relation to vagal nerve roots at the entrance to medulla oblongata. The aim of the study was to evaluate the effect of C1-C2 occipital neuromodulation on autonomic activity, body mass, and composition.
Methods: Five obese patients were included in the study (three women and two men, BMI 43-49, average age 43.3, range 24-55). Two electrodes were placed bilaterally in the C1-C2 region subcutaneously under local anesthesia. Stimulation was started 24 h after implantation and continued for 8 weeks. Patients activated stimulators for 12 h every day and turned the stimulators off at night. No other treatment including diet or change in lifestyle was introduced during the study. The following parameters were evaluated: body mass (0, 4th, and 8th week), body composition (bioimpedance study), food intake, quality of life, and heart rate variability (HRV) (0 and 8th week).
Results: No adverse events were observed in this group. One patient reported amelioration of constipation and one reported two incidents of salivation. The average body mass decrease was 5.6 kg in 4 weeks and 8.7 kg in 8 weeks. Body composition study showed a 2-month decrease in body fat of 7.9 kg on average. HRV revealed increased parasympathetic tone (LF/HF 4.4 ± 4.3 SD vs. 1.6 ± 1.7 SD).
Conclusions: C1-C2 occipital stimulation seems being capable of decreasing body mass and affecting a positive shift in body composition and significantly increases the activity of the autonomic nervous system.