ABSTRACT
We present the case of a 10-year-old boy who presents with a severe epilepsy resistant to medical treatment in the context of a Miller-Dieker syndrome. This patient underwent the implantation of a pneumogastric nerve stimulator. We describe the patient's clinical history and the main characteristics of lissencephaly syndrome.
Subject(s)
Abnormalities, Multiple/genetics , Brain/abnormalities , Epilepsy/genetics , Abnormalities, Multiple/diagnosis , Brain/diagnostic imaging , Child , Cryptorchidism/etiology , Electric Stimulation Therapy/methods , Electrodes, Implanted , Epilepsy/diagnosis , Epilepsy/therapy , Hirschsprung Disease/etiology , Humans , Hydrocephalus/etiology , Karyotyping , Male , Radiography , Syndrome , Treatment Outcome , Vagus Nerve/physiologyABSTRACT
The analgesic effect of vagus nerve stimulation (VNS) has not yet been demonstrated in animals with the devices used in the clinic. We studied in awake rats the effects of two VNS protocols on the hind paw hot water test and compared the results with those previously obtained in the oro-facial formalin test. A stringent duty cycle (20 s on/18 s off) increased heat pain tolerance in both hind paws (average 188%) after 2 h of stimulation. VNS with parameters used in epilepsy (30 s on/5 min off) decreased heat tolerance after 2 h, but produced a significant antinociceptive effect after days of stimulation. VNS may thus be useful in pain disorders, even with the less stringent protocol.
Subject(s)
Electric Stimulation Therapy/methods , Pain Management , Pain Threshold/physiology , Vagus Nerve/physiology , Animals , Brain/physiology , Efferent Pathways/physiology , Hot Temperature/adverse effects , Male , Neural Inhibition/physiology , Pain/physiopathology , Pain Measurement , Rats , Rats, Wistar , Reaction Time/physiology , Spinothalamic Tracts/physiologyABSTRACT
Besides its well-established efficacy in epilepsy, vagus nerve stimulation (VNS) may be of potential interest in pain treatment. It has, however, not yet been assessed in animal pain models with the devices and stimulation protocols used in humans. We have therefore studied in awake rats the effects of left cervical VNS on trigeminal nociception using an implantable electrode and stimulator (NCP-Cyberonics). VNS was applied for 24h at 2 mA intensity, 20 Hz frequency, 0.5 ms pulse width and a duty cycle of 20s ON/18s OFF. As a nociceptive stimulus, we injected formalin into the left mystacial vibrissae, assessed behaviour for 45 min and sacrificed the animals 45 min later. Fos-immunoreactive (Fos-Ir) neurons were counted in laminae I-II of trigeminal nucleus caudalis (TNC) on both sides. We used three groups of control animals: VNS without formalin, formalin without VNS and sham VNS (implanted without stimulation or formalin). Whereas sham VNS had no significant effect, VNS alone increased Fos expression in ipsilateral TNC in addition to the expected increase in nucleus tractus solitarius. It also significantly attenuated the increase of Fos-Ir neurons observed in ipsilateral TNC laminae I-II after formalin injection. If the proper VNS effect on Fos-expression was subtracted, the reduction of formalin-induced nociceptor activation was 55%. VNS also reduced nociceptive behaviour on average by 96.1% during the early phase (0-6 min) and by 60.7% during the late phase (6-45 min) after the formalin injection. These results suggest that VNS applied with a device used in human therapy may have in awake rats a significant antinociceptive effect in a model of trigeminal pain.
