TOTAL INTRAVENOUS ANAESTHESIA FOR INTRA–OPERATIVE NEUROPHYSIOLOGICAL MONITORING PRESERVING CRANIAL NERVES DURING CEREBELLOPONTINE ANGLE TUMOUR DISSECTION–A CASE REPORT.

Dr Anupananda Chowdhury; Dr Nobin Roy

Volume : X, Issue : II, February - 2020

TOTAL INTRAVENOUS ANAESTHESIA FOR INTRA–OPERATIVE NEUROPHYSIOLOGICAL MONITORING PRESERVING CRANIAL NERVES DURING CEREBELLOPONTINE ANGLE TUMOUR DISSECTION–A CASE REPORT.

Dr Anupananda Chowdhury, Dr Nobin Roy

Abstract :

OBJECTIVE: Effect of Total Intravenous Anaesthesia(TIVA) on neurophysiological monitoring , preserving cranial nerves during cerebellopontine angle tumour dissection. CASE REPORT: A 50 year old male patient presented with unilateral heå loss, tinnitus, generalized weakness, right sided facial hypesthesia and tongue deviation for the last two months.Intubation was done with loading dose of inj rocuronium 0.6mg/kg. Anaesthesia was maintained with infusion propofol @ 100µg/kg/min and inj fentanyl 1µg/kg keeping BIS within 40 to 60 and TOF < 0.7. Computerized electrodes are connected to frontalis,orbicularis oculi and oris, mentalis, masseter, trapezius, tongue and abductor pollis evis muscle corresponding to cranial nerves VII,III,XI,XII and median nerve for neurophysiological monitoring integrating cortical sensory evoked potential(SSEP) and Transcranial motor evoked potential(TcMEP). OBSERVATIONS: Propofol induction produced amplitude depression in cortical SSEPs with rapid recovery after termination of infusion.With electrical or magnetic elicited MEPs it had demonstrated a depressant effect on response amplitude,consistent with cortical effect.Although propofol did not appear to enhance cortical response ,rapid metabolism allows rapid adjustment of the depth of anaesthesia and effects on evoked potential.Fentanyl produced minimal changes in spinal and sucortical SSEP recordings and some depression of amplitude and an increase of latency in the cortical response.Myogenic response from MEPs with electrical and magnetic stimulation showed only mild amplitude decreases and latency increased with the opiods. CONCLUSION: TIVA has minimal effect on SSEP and TcMEP thus facilitating smooth intraoperative neurophysiological monitoring,however the critical component of teamwork underlies the entire process