evaluation of trigeminocardiac reflex during le fort i and sagittal split ramus osteotomies

i ntroduction:   the  trigeminocardiac  reflex  (tcr)  refers  to  the  sudden development of bradycardia as well as asystole along with arterial hypotension associated with any manipulation of sensory branches of the trigeminal nerve. clinically, the tcr has been reported to occur during craniofacial surgery. it is crucial to learn about this sudden physiological response during maxillofacial surgery that is likely to happen with any craniofacial surgical procedures. materials and methods: in  this clinical study 44 volunteers without any systemically compromising conditions were divided into 2 groups. the first group underwent le fort i osteotomy and the second mandibular osteotomy. mean  arterial  blood  pressure  and  pulse  rate  (mabp1,  pr1)  values  were recorded before down fracture (df) of maxilla and sagittal splitting (ss) of mandible, during df and ss (mabp2, pr2), and after df and ss (mabp3, pr3). the data were analyzed using repeated measure anova tests (p =0.05). result: in le fort i group, pr1 and pr3 were significantly higher than pr2 (p< .001). mabp2 was significantly lower compared with mabp1 and mabp3 (p < .001). pr2 and mabp2 showed a mean decrease of 7.4% and 8.9%  compared  with  pr1  and  mabp1,  respectively.  in  second  group differences on mabp and pr was not statistically significant. conclusion: it is concluded that tcr is triggered by the stimulation of v2 but v3 branch stimulation does not cause such reflex.