Pooyan Sadr-Eshkevari

Trigeminocardiac reflex: the current clinical and physiological knowledge.

The trigeminocardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. Clinically, the TCR has been reported in all the surgical procedures in which a structure innervated by the trigeminal nerve is involved. Although, there is an abundant literature with reports of incidences and risk factors of the TCR; the physiological significance and function of this brainstem reflex has not yet been fully elucidated. In addition, there are complexities within the TCR that requires examination and clarification. There is also a growing need to discuss its cellular mechanism and functional consequences. Therefore, the current review provides an updated examination of the TCR with a particular focus on the mechanisms and diverse nature of the TCR.

Trigeminocardiac reflex: A MaxFax literature review

Trigeminocardiac reflex (TCR) is a shocking event in the course of operation involving the maxillofacial area. The authors have tried to present an overview on the history, clinical implications, literature review, anatomic and biologic basis, predisposing and triggering factors, and management of the event. Being familiar with the presentations, preventive measures, and management procedures are seemingly the most important aspects of the TCR to oral and maxillofacial surgeons and anesthesiologists.

Trigeminocardiac reflex during Le Fort I osteotomy: a case-crossover study

OBJECTIVE The present study aimed to assess the occurrence of trigeminocardiac reflex (TCR) during Le Fort I osteotomies. STUDY DESIGN This case-crossover study included 25 Le Fort I osteotomy candidates without systemically compromising conditions. Mean arterial blood pressure and pulse rate values were recorded before downfracture (DF) (MABP1, PR1), during DF (MABP2, PR2), and after DF (MABP3, PR3). The data were analyzed using repeated measure ANOVA tests (alpha = 0.05). RESULTS PR1 and PR3 were significantly higher than PR2 (P < .001). MABP2 value was significantly lower compared with MABP1 and MABP3 values (P < .001). PR2 and MABP2 showed a mean decrease of 6.5% and 9.7% compared with PR1 and MABP1, respectively. CONCLUSION Different values have been suggested for TCR. Considering the limitations, the present study may suggest a revision of the values or descriptions for TCR, at least in maxillofacial Le Fort I osteotomy.

The trigemino-cardiac reflex in adults: own experience

The trigemino-cardiac reflex The trigemino-cardiac reflex (TCR) has previously been described in the literature as a reflexive response composed of bradycardia, hypotension and gastric hypermotility seen upon mechanical stimulation anywhere in the distribution of the trigeminal nerve [1–5]. Based on the initial rabbit neurostimulation experiments of Kumada et al. in 1977 [6], TCR was first observed by Schaller et al. in 1999 during neurosurgical operations [5]. By systematic observation, the incidence of the TCR during neurosurgical procedures around the trigeminal nerve was shown to be approximately 10–18%, independently of the surgeon who operated or the approach that was used [3,7–12]. In their key works, Schaller et al. first defined TCR in detail, and their observations are at present generally accepted [3,5,13–15].

Trigeminocardiac Reflex, Bilateral Sagittal Split Ramus Osteotomy, Gow-Gates Block: A Randomized Controlled Clinical Trial

PURPOSE The behavior of trigeminocardiac reflex (TCR) during maxillofacial surgeries has not yet been sufficiently studied and knowledge of its behavior is limited to some case reports. The present study aimed to assess the occurrence of TCR in bilateral sagittal split ramus osteotomy and to determine the possible effect of Gow-Gates block on its incidence. MATERIALS AND METHODS Twenty candidates for bilateral sagittal split ramus osteotomy (included were American Society of Anesthesiologists I Class III patients with a prognathism of 3 to 5 mm) were given routine general anesthesia after at least 12 hours of fasting. All patients received Gow-Gates mandibular nerve block on 1 random side (case ramus; the other side was used as the control) after induction of general anesthesia before surgery. Pulse rate was recorded at baseline, soft tissue cutting, bone cutting, sagittal splitting, setback manipulation, and recovery. Mean pulse rate values were compared statistically using t test for the 2 sides in patients. RESULTS No statistically significant differences were found between the blocked and control sides except during ramus sagittal splitting and setback manipulation (P < .0001), when a significantly decreased pulse rate was recorded for the control ramus compared with the blocked ramus. CONCLUSIONS The present study provides further evidence for the complex neurophysiologic mechanism and probable prevention of peripheral TCR. The results of the present study should be further validated through future studies but already provide strong evidence that peripheral and central TCR may act differently based on slightly different pathways.

Trigeminocardiac reflex: current trends.

Since the first introduction of the trigeminocardiac reflex (TCR) in 1999, substantial new knowledge about this brainstem reflex has been created. First, by different clinical case reports and case studies, and second, from basic research that gives inputs from bench to bedside. In the present work, the authors therefore introduce the molecular/anatomical knowledge of the TCR and show its different connections to clinical aspects. Special reference is given to prevention and treatment of the TCR; but always with a link to knowledge of the basis sciences. In such a context different topics of future interest are introduced.

Trigeminocardiac Reflex in Neurosurgery - Current Knowledge and Prospects

Amr Abdulazim1, Martin N. Stienen1, Pooyan Sadr-Eshkevari2, Nora Prochnow1, Nora Sandu4, Benham Bohluli3 and Bernhard Schaller4 1Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, Bochum, 2Farzan Clinical Research Institute,Teheran, 3Department of Oral and Maxillofacial Surgery, Tehran Azad School of Dental Medicine, Tehran, 4Department of Neurosurgery, University of Paris, Paris, 1Germany 2,3Iran 4France

Trigeminocardiac reflex: Some thought to the definition.

Dear Editor, We read with great interest one of the rare prospective studies related to the Trigeminocardiac Reflex (TCR) by Etezadi et al. in the September issue of the Surgical Neurology International.[6] Given the fact that most TCR evidence is based upon case reports and case series,[9] the importance of such studies become more evident. The TCR has long suffered from a lack of proper evidence for a couple of reasons: First, the nomenclature has been partly misleading, as trigeminal stimulation has been only linked to cardiac and cardiovascular changes,[10,13,14] as these are most evident during operation. It should be noted that TCR is originally coined to describe concrete autonomic changes upon stimulation of the trigeminal nerve. These changes include “sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve”.[13] None of the clinical assessments of TCR, to the best of our knowledge, have hitherto concerned the big picture.[3] Second, the reflex is elicited by the maneuvers around any of the branches of cranial nerve V or allegedly upon stimulation of Gasserian ganglion or trigeminal brainstem centers.[11,13] A direct cause and effect assessment of the trigger point of the reflex, however, is ethically not possible in humans unless in proper animal models,[9] but a generally accepted and clinically driven model, which is properly and sufficiently studied, is lacking.[1] Third, the original definition of the reflex did only describe the central part of the reflex[14] and not triggering of the reflex during stimulation of peripheral part, Gasserian ganglion or brainstem trigeminal centers and nuclei,[4,10] a fact that was only discovered recently. Proper definition of the reflex is currently an ongoing debate driven by the continuous new knowledge on this reflex.[4] Fourth, the 20% cut-off of the TCR[14] seems to decrese the true incidence of the reflex,[4] but is the best instrument to exclude common cardiovascular disturbances that are seen during operations and are not related to the reflex. According to Bohluli et al., who for the first time, systematically studied the occurrence of TCR in maxillofacial procedures through clinical trials, a mean decrease of 6.5% and 9.7% compared with baseline was recorded for Le-Fort I osteotomy, respectively, in pulse rate and mean arterial blood pressure.[2] Also in bilateral sagittal split ramus osteotomy, the locally blocked side was associated with mean decreases of 4.6% and 6.8% during splitting and manipulation, respectively, compared with baseline while these values were 17.6% and 21.5% in the control ramus.[3] It seemed that the 20% cut-off is only resulting in the exclusion of the actual cases of occurrence of TCR. Since the magnitude of the reflex seemed to be a factor of aggression of the surgical maneuver – needs verification – the reflex could always be expected and its rate is much higher that what is described throughout the literature. Fifth, not every bradycardia is TCR:[12,14] Besides the strict definition, there is a need of a clear “cause-/effect-relationship. If such clear definitions are used in every case, comparisons of the works related to TCR would be possible and consecutively systematic reviews would be help to create new knowledge.[9] Last, it is thought that the reflex involves coactivation of the sympathetic and parasympathetic reflex.[8] This belief stems mainly in oculocardiac reflex (OCR), which is part of the peripheral TCR,[10] research that has been far more extensive compared to TCR. The incidence of OCR during eye surgery is reportedly significant especially during strabismus surgery.[5] In patients with suppressed vagal tone, ventricular ectopic beats can occur along with reduced bradycardia, which could lead to an increasedrisk of arrhythmias.[7] Based on these findings and observations, the definition of TCR is an ongoing work that is substantially influenced by the continuous and increasingly new knowledge on this reflex.[4] With these new suggestions, as published recently,[4] another interesting approach to study the occurrence of TCR will be to record the mean arterial blood pressure and pulse rate drop compared with the baseline, which is immediately before the stimulation and to report the relative magnitude of the reflex for each procedure. Needless to say, the 20% decrease will still be helpful to report the “more clinically concerning” event of the reflex.

Alveolar bone stress around implants with different abutment angulation: an FE-analysis of anterior maxilla.

Objectives:To comparatively assess the masticatory stress distribution in bone around implants placed in the anterior maxilla with three different labial inclinations. Materials and Methods:Three-dimensional finite element models were fabricated for three situations in anterior maxilla: (1) a fixture in contact with buccal cortical plate restored by straight abutment, (2) a fixture inclined at 15 degrees, and (3) 20 degrees labially restored with corresponding angled abutment. A palatal bite force of 146 N was applied to a point 3 mm below the incisal edge. Stress distribution around the bone-fixture interface was determined using ANSYS software. Results:The maximum compressive stress, concentrated in the labial crestal cortical bone, was measured to be 62, 108, and 122 MPa for 0-, 15-, and 20-degree labially inclined fixtures, respectively. The maximum tensile stress, concentrated in the palatal crestal cortical bone, was measured to be 60, 108, and 120 MPa for 0-, 15-, and 20-degree labially inclined fixtures, respectively. Conclusions:While all compressive stress values were under the cortical yield strength of 169 MPa, tensile stress values partially surpassed the yield strength (104 MPa) especially when a 20-degree inclination was followed for fixture placement.

Surgically Assisted Rapid Palatomaxillary Expansion With or Without Pterygomaxillary Disjunction: A Systematic Review and Meta-Analysis.

PURPOSE The purpose of this review was to evaluate the outcome measurements of anterior expansion, posterior expansion, and complications after surgically assisted rapid palatal expansion (SARPE) with or without pterygomaxillary disjunction (PMD). MATERIALS AND METHODS A computerized database search was performed using PubMed, CINAHL, Cochrane, Scopus, and Web of Science. Then, a computerized search was conducted in Google Scholar and ProQuest to overcome publication bias. RESULTS From the original 125 combined results, 3 met the inclusion criteria. The Quality Assessment Tool for Quantitative Studies of the Effective Public Health Practice Project assessed 2 articles as weak and 1 as moderate. The systematic review included a total of 48 patients (11 male and 37 female). For 25 patients, SARPE was performed with PMD and for 23 patients SARPE was performed without PMD. A tooth-borne fixed hyrax-type palatal expansion screw appliance was used for all cases, activated 1 to 2 mm intraoperatively, and, after a latency period of 3 to 7 days, activated 0.5 to 0.6 mm per day for 38 patients and 0.25 mm for the other 10 until adequate expansion. Postexpansion retention was performed using ligature wired hyrax in 18 patients for 4 months. Comparisons were based on cone-beam computed tomographic projections, study models only, or a combination of study models, anteroposterior cephalometric radiographs, and occlusal radiographs. The time to measure the changes ranged from before fixed orthodontic retention to 6 months after the completion of active expansion. A meta-analysis was possible only for anterior (intercanine) and posterior (inter-molar) dental expansions. CONCLUSION The literature is inconclusive regarding the effect of PMD on the outcomes of SARPE. Further controlled trials are needed.