- Email: [email protected]
Trigeminocardiac reflex during Le Fort I osteotomy: a case-crossover study
Trigeminocardiac reflex during Le Fort I osteotomy: a case-crossover study Behnam Bohluli, DDS, MS,a Mohammad Bayat, DMD, MS,b Farzin Sarkarat, DDS, MS,a Behnaz Moradi, DDS,c Mohammad-Hassan Seif Tabrizi, DDS,d and Pooyan Sadr-Eshkevari, DDS,c Tehran, Iran, and Malaya, Malaysia AZAD UNIVERSITY OF TEHRAN, TEHRAN UNIVERSITY OF MEDICAL SCIENCES, PRIVATE PRACTICE, AND UNIVERSITY OF MALAYA
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 (␣ ⫽ 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. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:178-181)
Trigeminocardiac reflex (TCR), a sudden decrease in pulse rate (PR) and mean arterial blood pressure (MABP) that may consequently develop asystole and even cardiac arrest, is of high importance to oral and maxillofacial surgeons. This is especially true during the course of Le Fort and mandibular osteotomies. This abrupt event is reported more than 20 times through the oral and maxillofacial surgery literature. TCR is reported during the corrective surgery of nasal fracture and midface fracture reduction, tuberosity osteotomy, Le Fort I osteotomy, sagittal-split osteotomy of rami, reduction of fractured zygomas, and even arthroscopic surgeries of temporomandibular joint (TMJ).1 The prevalence of TCR has been reported to be 1.6% during maxillofacial, temporomandibular, and orthognathic surgeries. Also, there have been reports of sudden MABP or PR decrease in the course of intraoral surgeries and extractions.2 a
Assistant Professor, Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Azad University of Tehran, Tehran, Iran. b Assistant Professor, Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran. c Private Practice, Tehran, Iran. d Resident of Oral and Maxillofacial Surgery, Department of Oral and Maxillofacial Surgery, University of Malaya, Malaya, Malaysia. Received for publication Sep 15, 2009; returned for revision Dec 12, 2009; accepted for publication Dec 28, 2009. 1079-2104/$ - see front matter © 2010 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2009.12.054
178
Different theories have been suggested to describe TCR. The mechanism of action of TCR, however, remains unclear. Some authors suggest anxiety as a contributing factor. Some others have discussed the type of anesthetic agents as an influential factor.3,4 A third theory introduces the stimulation of lingual and palatal branches of the trigeminal nerve as the triggering factor.5 Because the occurrence of this reflex may be associated with threatening consequences without any significant signs, its prevention and management are crucial to the surgeon and anesthesiologist.1 Authors have suggested the intravenous administration of anticolinergics for prevention of TCR. Others believe that the only proper strategy is to stop the stimulating action until MABP and PR reach the baseline.6 Failure to manage this event may result in asystole, and even cardiac arrest in some cases.1,7 Though oculocardiac reflex (OCR), a subtype of TCR, has been thoroughly studied through the ophthalmology literature, TCR has not yet been sufficiently discussed among oral and maxillofacial surgeons.1,3 Because the maxillofacial literature on TCR is limited to case reports and a literature review by the authors,1 it was decided to further assess the occurrence of TCR during Le Fort I osteotomies. MATERIALS AND METHODS Overview This case-crossover study was peer reviewed and approved by local board of ethics. Informed consents
OOOOE Volume 110, Number 2
Bohluli et al. 179
were obtained after providing candidates with sufficient information about the study. Patients Included were 25 Le Fort I osteotomy candidates consecutively referred to our center during a 5-month period. This number was based on the pilot study outcomes on 10 patients. Excluded were patients with systemic problems, mental or neurologic disorders, antidepressant use, cardiovascular problems, and patients with unexpected events during the course of surgery. The study primarily included 30 patients, 5 of whom were excluded because of uncontrolled MABP, administration of excess drugs during surgery, disconnection of airways, and so forth. The study then included 25 Le Fort I candidates with a mean age of 24.6 ⫾ 1.6 years (range, 18-39 years). Of the study population, 30% were females and 70% were males. Candidates were interviewed upon referral and their health status was recorded. All surgeries were performed by one oral and maxillofacial surgeon. General hypotensive anesthesia was administered using propofol and remifentanil, which were continued during the surgery. After general anesthesia was administered, MABP and PR were constantly monitored by pulse oximeter until downfracture (DF) and the least values were recorded (MABP1 and PR1). These values were also recorded at the time of DF (MABP2 and PR2). Finally, MABP and PR were constantly monitored after DF and the least values were recorded (MABP3 and PR3). Statistics Data were recorded in SPSS v16 (SPSS, Chicago, IL). Based on One-Sample Kolmogorov-Smirnov test, data were of normal distribution. The data were then statistically analyzed using repeated measure analysis of variance (ANOVA) test (␣ ⫽ 0.05). RESULTS Figures 1 and 2 represent respectively the MABP and the PR alterations of the study population. The MABP of each patient before and after DF could have been used, which demanded extra recordings and measurements and did not seem necessary to the authors. The steady blood pressure a few seconds before and a few seconds after DF was then used. PR1 and PR3 were significantly higher than PR2 (P ⬍ .001). PR1 and PR3, however, did not show any statistically significant difference (P ⫽ .682). Patients’ age and gender did not seem to influence the results. MABP followed the same pattern as PR before, during, and after Le Fort I DF. MABP2 value was significantly lower compared with MABP1 and MABP3 values (P ⬍ .001). Similar to PR, no statistically significant differ-
Fig. 1. The comparative illustration of the mean values of PR before, during, and after DF. PR2 was associated with a mean decrease of 6.5% compared with PR1.
Fig. 2. The comparative illustration of the mean values of MABP before, during, and after DF. MABP2 was associated with a mean decrease of 9.7% compared with MABP1.
ences were found between MABP1 and MABP3 (P ⫽ .122). Compared with baseline PR values, 25% of the patients showed a PR decrease of more than 10% at DF. Also 45.8% of the patients showed a MABP decrease of more than 10% during DF compared with the baseline values. DISCUSSION The present study showed a significant decrease of MABP and PR during DF compared with the values obtained before and after DF during the course of Le Fort I surgery. DF was associated with a 6.5% decrease in PR values and a 9.7% decrease in the MABP values from those of baseline. The present study showed that DF is associated with significant MABP and PR decrease. This is thought to be attributed to the stimulation of the maxillary branch of the trigeminal nerve that innervates the midface. TCR is a relatively unknown reflex that has recently received considerable attention. Little is known about
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the mechanism and function of this reflex.2 Three hypotheses have been suggested to describe the mechanism of TCR. Because of the anatomy of the trigeminocardiac nerve and its relation to the vagus nerve and also according to the findings of the present study, the third hypothesis is seemingly more probable. On the other hand, our findings may reject the 2 other hypotheses because the patients have been under general anesthesia and fear would not be the etiology. Also lidocaine was not administered to the patients and epinephrine was used within the serum. The reflex could then be the result of stimulation of any branch of the trigeminal nerve or the main nerve trunk. The sensory branches of the trigeminal nerve send signals from the Gasserian ganglion to the sensory nucleus of the trigeminal nerve (the afferent pathway of TCR). The signals are then transferred to the vagus motor nucleus via short nerves and directed to the myocardium via the cardiac branch of the vagus nerve (the afferent pathway of TCR).1-3 As previously stated, the literature on the occurrence of TCR in the course of maxillary and mandibular osteotomies is limited to case reports.1 Surgeries involving other parts of the head and neck are probably more thoroughly studied in terms of TCR incidence and mechanism. Robideaux8 reported a case of abrupt PR decrease from 90 to 54 per minute in a 22-year-old male during the reduction surgery of fractured maxilla. Lang et al.9 reported a 38-year-old female with no history of systemic disease and a normal baseline electrocardiogram (ECG) who experienced a sudden PR decrease of 30 per minute during maxillary advancement manipulations. The situation was resolved immediately after the manipulation was stopped by the surgeon. They also reported 3 other cases within a year that showed bradycardia and ventricular asystole in response to the stimulation of maxillary and mandibular branches of trigeminal nerve during an osteotomy.9 Bainton et al.10 discussed a case of sinus node arrest (cessation of the sino-atrial node activity) during bicoronal osteotomy to correct facial fractures. These reports are all in accordance with the clinical presentation of TCR that occurred in the present study. Almost concurrently, Skulsky and Precious11 stated that cardiac asystole, bradycardia, and any other dysrhythmias have been thoroughly discussed through the ophthalmologic literature and emphasized a lack of evidence in the maxillofacial literature. They reported a case series of 8 (1.6%) of 500 patients with the occurrence of TCR during the advancement of maxilla (6 cases), and also the manipulation of the temporalis muscle during corrective surgery of the TMJ (2 cases). The prevalence of TCR in the present study seems to be
significantly higher than that of Lang et al.9 This is thought to be attributed to the different description of the TCR applied to the present study. In the present study, a 10% or higher decrease in the PR and MABP levels from baseline was considered as TCR. In the study of Lang et al.,9 however, this value was 20% or higher. On the other hand, the present study included only Le Fort I surgery cases, whereas Lang et al., surveyed maxillofacial surgery cases. Also, based on a case of a 29-year-old female, they suggested the auriculotemporal nerve as the afferent pathway of the reflex. Sufentanil and alfentanil (strong narcotics), beta-blockers and calcium channel blockers, hypocalcemia, and increased blood levels of CO2, stimulation (type and intensity) are predisposing factors for the occurrence of OCR. Many surgeons routinely bathe the descending palatine neurovascular structures with lidocaine as soon as they are visible in the DF process, but in any case always before the maxilla is manipulated to achieve its final advanced position to prevent incidence of asystole.1 The effect of these factors on TCR is yet unknown but likely to be the same as OCR. Further studies are needed to investigate the issue. CONCLUSIONS 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. It seems that TCR is more prevalent than what was previously thought during Le Fort osteotomy surgery. REFERENCES 1. Bohluli B, Ashtiani AK, Khayampoor A, Sadr-Eshkevari P. Trigeminocardiac reflex: a MaxFax literature review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;108(2): 184-8. 2. Barnard NA, Bainton R. Bradycardia and the trigeminal nerve. J Craniomaxillofac Surg 1990;18(8):359-60. 3. Schaller B. Trigeminocardiac reflex. A clinical phenomenon or a new physiological entity? J Neurol 2004;251(6):658-65. 4. Cha ST, Eby JB, Katzen JT, Shahinian HK. Trigeminocardiac reflex: a unique case of recurrent asystole during bilateral trigeminal sensory root rhizotomy. J Craniomaxillofac Surg 2002;30(2): 108-11. 5. Kayikçioglu O, Kayikçioglu M, Erakgün T, Güler C. Electrocardiographic changes during subconjunctival injections. Int Ophthalmol 1999;23(1):37-41. 6. Koerbel A, Gharabaghi A, Samii A, Gerganov V, von Gösseln H, Tatagiba M, et al. Trigeminocardiac reflex during skull base surgery: mechanism and management. Acta Neurochir (Wien) 2005;147(7):727-32; discussion 732-3. 7. Prabhakar H, Anand N, Chouhan RS, Bithal PK. Sudden asystole during surgery in the cerebellopontine angle. Acta Neurochir (Wien) 2006;148(6):699-700; discussion 700. 8. Robideaux V. Oculocardiac reflex caused by midface disimpaction. Anesthesiology 1978;49(6):433.
OOOOE Volume 110, Number 2 9. Lang S, Lanigan DT, van der Wal M. Trigeminocardiac reflexes: maxillary and mandibular variants of the oculocardiac reflex. Can J Anaesth 1991;38(6):757-60. 10. Bainton R, Barnard N, Wiles JR, Brice J. Sinus arrest complicating a bitemporal approach to the treatment of pan-facial fractures. Br J Oral Maxillofac Surg 1990;28(2):109-10. 11. Precious DS, Skulsky FG. Cardiac dysrhythmias complicating maxillofacial surgery. Int J Oral Maxillofac Surg 1990;19(5):279-82.
Bohluli et al. 181 Reprint requests: Pooyan Sadr-Eshkevari, DDS Private Practice 51 Shahid Siami Sattarkhan Blvd Tehran, Tehran 1441684971 Iran [email protected]
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 (␣ ⫽ 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. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:178-181)
Trigeminocardiac reflex (TCR), a sudden decrease in pulse rate (PR) and mean arterial blood pressure (MABP) that may consequently develop asystole and even cardiac arrest, is of high importance to oral and maxillofacial surgeons. This is especially true during the course of Le Fort and mandibular osteotomies. This abrupt event is reported more than 20 times through the oral and maxillofacial surgery literature. TCR is reported during the corrective surgery of nasal fracture and midface fracture reduction, tuberosity osteotomy, Le Fort I osteotomy, sagittal-split osteotomy of rami, reduction of fractured zygomas, and even arthroscopic surgeries of temporomandibular joint (TMJ).1 The prevalence of TCR has been reported to be 1.6% during maxillofacial, temporomandibular, and orthognathic surgeries. Also, there have been reports of sudden MABP or PR decrease in the course of intraoral surgeries and extractions.2 a
Assistant Professor, Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Azad University of Tehran, Tehran, Iran. b Assistant Professor, Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran. c Private Practice, Tehran, Iran. d Resident of Oral and Maxillofacial Surgery, Department of Oral and Maxillofacial Surgery, University of Malaya, Malaya, Malaysia. Received for publication Sep 15, 2009; returned for revision Dec 12, 2009; accepted for publication Dec 28, 2009. 1079-2104/$ - see front matter © 2010 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2009.12.054
178
Different theories have been suggested to describe TCR. The mechanism of action of TCR, however, remains unclear. Some authors suggest anxiety as a contributing factor. Some others have discussed the type of anesthetic agents as an influential factor.3,4 A third theory introduces the stimulation of lingual and palatal branches of the trigeminal nerve as the triggering factor.5 Because the occurrence of this reflex may be associated with threatening consequences without any significant signs, its prevention and management are crucial to the surgeon and anesthesiologist.1 Authors have suggested the intravenous administration of anticolinergics for prevention of TCR. Others believe that the only proper strategy is to stop the stimulating action until MABP and PR reach the baseline.6 Failure to manage this event may result in asystole, and even cardiac arrest in some cases.1,7 Though oculocardiac reflex (OCR), a subtype of TCR, has been thoroughly studied through the ophthalmology literature, TCR has not yet been sufficiently discussed among oral and maxillofacial surgeons.1,3 Because the maxillofacial literature on TCR is limited to case reports and a literature review by the authors,1 it was decided to further assess the occurrence of TCR during Le Fort I osteotomies. MATERIALS AND METHODS Overview This case-crossover study was peer reviewed and approved by local board of ethics. Informed consents
OOOOE Volume 110, Number 2
Bohluli et al. 179
were obtained after providing candidates with sufficient information about the study. Patients Included were 25 Le Fort I osteotomy candidates consecutively referred to our center during a 5-month period. This number was based on the pilot study outcomes on 10 patients. Excluded were patients with systemic problems, mental or neurologic disorders, antidepressant use, cardiovascular problems, and patients with unexpected events during the course of surgery. The study primarily included 30 patients, 5 of whom were excluded because of uncontrolled MABP, administration of excess drugs during surgery, disconnection of airways, and so forth. The study then included 25 Le Fort I candidates with a mean age of 24.6 ⫾ 1.6 years (range, 18-39 years). Of the study population, 30% were females and 70% were males. Candidates were interviewed upon referral and their health status was recorded. All surgeries were performed by one oral and maxillofacial surgeon. General hypotensive anesthesia was administered using propofol and remifentanil, which were continued during the surgery. After general anesthesia was administered, MABP and PR were constantly monitored by pulse oximeter until downfracture (DF) and the least values were recorded (MABP1 and PR1). These values were also recorded at the time of DF (MABP2 and PR2). Finally, MABP and PR were constantly monitored after DF and the least values were recorded (MABP3 and PR3). Statistics Data were recorded in SPSS v16 (SPSS, Chicago, IL). Based on One-Sample Kolmogorov-Smirnov test, data were of normal distribution. The data were then statistically analyzed using repeated measure analysis of variance (ANOVA) test (␣ ⫽ 0.05). RESULTS Figures 1 and 2 represent respectively the MABP and the PR alterations of the study population. The MABP of each patient before and after DF could have been used, which demanded extra recordings and measurements and did not seem necessary to the authors. The steady blood pressure a few seconds before and a few seconds after DF was then used. PR1 and PR3 were significantly higher than PR2 (P ⬍ .001). PR1 and PR3, however, did not show any statistically significant difference (P ⫽ .682). Patients’ age and gender did not seem to influence the results. MABP followed the same pattern as PR before, during, and after Le Fort I DF. MABP2 value was significantly lower compared with MABP1 and MABP3 values (P ⬍ .001). Similar to PR, no statistically significant differ-
Fig. 1. The comparative illustration of the mean values of PR before, during, and after DF. PR2 was associated with a mean decrease of 6.5% compared with PR1.
Fig. 2. The comparative illustration of the mean values of MABP before, during, and after DF. MABP2 was associated with a mean decrease of 9.7% compared with MABP1.
ences were found between MABP1 and MABP3 (P ⫽ .122). Compared with baseline PR values, 25% of the patients showed a PR decrease of more than 10% at DF. Also 45.8% of the patients showed a MABP decrease of more than 10% during DF compared with the baseline values. DISCUSSION The present study showed a significant decrease of MABP and PR during DF compared with the values obtained before and after DF during the course of Le Fort I surgery. DF was associated with a 6.5% decrease in PR values and a 9.7% decrease in the MABP values from those of baseline. The present study showed that DF is associated with significant MABP and PR decrease. This is thought to be attributed to the stimulation of the maxillary branch of the trigeminal nerve that innervates the midface. TCR is a relatively unknown reflex that has recently received considerable attention. Little is known about
180
OOOOE August 2010
Bohluli et al.
the mechanism and function of this reflex.2 Three hypotheses have been suggested to describe the mechanism of TCR. Because of the anatomy of the trigeminocardiac nerve and its relation to the vagus nerve and also according to the findings of the present study, the third hypothesis is seemingly more probable. On the other hand, our findings may reject the 2 other hypotheses because the patients have been under general anesthesia and fear would not be the etiology. Also lidocaine was not administered to the patients and epinephrine was used within the serum. The reflex could then be the result of stimulation of any branch of the trigeminal nerve or the main nerve trunk. The sensory branches of the trigeminal nerve send signals from the Gasserian ganglion to the sensory nucleus of the trigeminal nerve (the afferent pathway of TCR). The signals are then transferred to the vagus motor nucleus via short nerves and directed to the myocardium via the cardiac branch of the vagus nerve (the afferent pathway of TCR).1-3 As previously stated, the literature on the occurrence of TCR in the course of maxillary and mandibular osteotomies is limited to case reports.1 Surgeries involving other parts of the head and neck are probably more thoroughly studied in terms of TCR incidence and mechanism. Robideaux8 reported a case of abrupt PR decrease from 90 to 54 per minute in a 22-year-old male during the reduction surgery of fractured maxilla. Lang et al.9 reported a 38-year-old female with no history of systemic disease and a normal baseline electrocardiogram (ECG) who experienced a sudden PR decrease of 30 per minute during maxillary advancement manipulations. The situation was resolved immediately after the manipulation was stopped by the surgeon. They also reported 3 other cases within a year that showed bradycardia and ventricular asystole in response to the stimulation of maxillary and mandibular branches of trigeminal nerve during an osteotomy.9 Bainton et al.10 discussed a case of sinus node arrest (cessation of the sino-atrial node activity) during bicoronal osteotomy to correct facial fractures. These reports are all in accordance with the clinical presentation of TCR that occurred in the present study. Almost concurrently, Skulsky and Precious11 stated that cardiac asystole, bradycardia, and any other dysrhythmias have been thoroughly discussed through the ophthalmologic literature and emphasized a lack of evidence in the maxillofacial literature. They reported a case series of 8 (1.6%) of 500 patients with the occurrence of TCR during the advancement of maxilla (6 cases), and also the manipulation of the temporalis muscle during corrective surgery of the TMJ (2 cases). The prevalence of TCR in the present study seems to be
significantly higher than that of Lang et al.9 This is thought to be attributed to the different description of the TCR applied to the present study. In the present study, a 10% or higher decrease in the PR and MABP levels from baseline was considered as TCR. In the study of Lang et al.,9 however, this value was 20% or higher. On the other hand, the present study included only Le Fort I surgery cases, whereas Lang et al., surveyed maxillofacial surgery cases. Also, based on a case of a 29-year-old female, they suggested the auriculotemporal nerve as the afferent pathway of the reflex. Sufentanil and alfentanil (strong narcotics), beta-blockers and calcium channel blockers, hypocalcemia, and increased blood levels of CO2, stimulation (type and intensity) are predisposing factors for the occurrence of OCR. Many surgeons routinely bathe the descending palatine neurovascular structures with lidocaine as soon as they are visible in the DF process, but in any case always before the maxilla is manipulated to achieve its final advanced position to prevent incidence of asystole.1 The effect of these factors on TCR is yet unknown but likely to be the same as OCR. Further studies are needed to investigate the issue. CONCLUSIONS 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. It seems that TCR is more prevalent than what was previously thought during Le Fort osteotomy surgery. REFERENCES 1. Bohluli B, Ashtiani AK, Khayampoor A, Sadr-Eshkevari P. Trigeminocardiac reflex: a MaxFax literature review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;108(2): 184-8. 2. Barnard NA, Bainton R. Bradycardia and the trigeminal nerve. J Craniomaxillofac Surg 1990;18(8):359-60. 3. Schaller B. Trigeminocardiac reflex. A clinical phenomenon or a new physiological entity? J Neurol 2004;251(6):658-65. 4. Cha ST, Eby JB, Katzen JT, Shahinian HK. Trigeminocardiac reflex: a unique case of recurrent asystole during bilateral trigeminal sensory root rhizotomy. J Craniomaxillofac Surg 2002;30(2): 108-11. 5. Kayikçioglu O, Kayikçioglu M, Erakgün T, Güler C. Electrocardiographic changes during subconjunctival injections. Int Ophthalmol 1999;23(1):37-41. 6. Koerbel A, Gharabaghi A, Samii A, Gerganov V, von Gösseln H, Tatagiba M, et al. Trigeminocardiac reflex during skull base surgery: mechanism and management. Acta Neurochir (Wien) 2005;147(7):727-32; discussion 732-3. 7. Prabhakar H, Anand N, Chouhan RS, Bithal PK. Sudden asystole during surgery in the cerebellopontine angle. Acta Neurochir (Wien) 2006;148(6):699-700; discussion 700. 8. Robideaux V. Oculocardiac reflex caused by midface disimpaction. Anesthesiology 1978;49(6):433.
OOOOE Volume 110, Number 2 9. Lang S, Lanigan DT, van der Wal M. Trigeminocardiac reflexes: maxillary and mandibular variants of the oculocardiac reflex. Can J Anaesth 1991;38(6):757-60. 10. Bainton R, Barnard N, Wiles JR, Brice J. Sinus arrest complicating a bitemporal approach to the treatment of pan-facial fractures. Br J Oral Maxillofac Surg 1990;28(2):109-10. 11. Precious DS, Skulsky FG. Cardiac dysrhythmias complicating maxillofacial surgery. Int J Oral Maxillofac Surg 1990;19(5):279-82.
Bohluli et al. 181 Reprint requests: Pooyan Sadr-Eshkevari, DDS Private Practice 51 Shahid Siami Sattarkhan Blvd Tehran, Tehran 1441684971 Iran [email protected]