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tunate choice of illustration. The authors would like to stress that in the 24 cases now treated by this technique not one has been complicated by an "unstable result". We have indeed addressed the medial extent of the osteotomy and do not use vertical eminotomy to limit it. Once the horizontal osteotomy has been commenced with a fissure burr to a depth of 1 cm, or a little more, a fine osteotome is driven into the osteotomy until the note of mallet/osteotome contact changes, signifying contact with dense bone in the region of the temporosphenoid suture. A sharp twist then completes the down-fracture. We have never had a problem with this technique and would suggest that the osteotomy created in this manner extends further medially than would be the case if it were limited by vertical eminotomy. We have not found it necessary to perform rigid fixation of either the down-fractured eminence or interpositional graft and use only tight periosteal closure with vicryl or PDS. In our experience recurrent subluxation/dislocation tends to be a bilateral problem if not at initial presentation certainly at a later stage in the natural history of the condition. In view
of the minimal morbidity of our technique it seems sensible to augment eminences bilaterally at one operation rather than submit the patient to two separate procedures. There should be no need for us to stress that cases should be assessed individually. Meticulous attention to haemostasis, the absence of temporalis muscle-splitting and limited dissection of tissue planes, obviates the need for vacuum or other types of surgical drainage or for that matter pressure dressings. Once again, cases should be assessed on their merits. There may be complications with drains and their indiscriminate use is to be deplored. The Dautry operation must involve increase in height of the eminence for surely if the "osseous buttress" referred to is to lie anterior to the condyle it must lie on the eminence which also lies anterior to the condyle. If it lies on the eminence then it must augment eminence height to some degree. Examination of a dried skull will confirm this point. It is because the "osseous buttress" so frequently fails to augment eminence height where it matters, that is medially, that the procedure is so unreliable. The authors would refer Mr. Mitchell
to the paper by Karabouta 1. She describes the use of Interpore 200 as an augmentation material. Similarities to the procedure we describe include: lack of vertical eminotomy, avoidance of rigid fixation, and no surgical drainage. We should point out that this paper was published after submission of our paper. Finally, we suggest that Mr. Mitchell and his senior colleague try our procedure. We are confident that he will find it an improvement on his current operation for temporomandibular joint hypermobility. After all, the proof of the pudding is in the eating. NICHOLAS M. WHEAR
I read with interest the article by Drs. Precious and Skulsky: "Cardiac dysrhythmias complicating maxillofacial surgery" (Int J Oral Maxillofac Surg 1990: 19: 279-82). The oculocardiac reflex is a similar phenomenon that has been extensively reported and is well known to ophthalmologists and anesthesiologists alike when undertaking surgery on the globe. I recently reported a 25% evidence of the OCR (25 of 100 prospectively studied patients) occurring in aesthetic blepharoplasty surgery. In that series a reflex prone patient was identified as: an anxious female (the sex may reflect the sample population) with some cardiac history (including elevated BP) having surgery under sedation and local (not general) anesthesia, and OCR occurring during traction on the eyelid fat pads. As Drs. Precious and Skulsky determined, we also found similar types of dysrhythmias, treatment requirements,
and that the OCR occurred while stretching tissue. It will be enlightening to review their ongoing prospective study in view of the inherent drawbacks that a retrospective study has; particularly when looking at a transient intraoperative event that may not be routinely recorded on a medical chart. Unlike our study it is feasible that the authors will have the opportunity of determining the extent of stretch-traction, (based on the amount of tissue advancement) that causes the cardiac dysrhythmias during maxillofacial surgery, providing additional valuable information. Due to the increasing incidence of ambulatory and office-based surgery we concluded that: awareness of this potentially fatal complication is important (and not to misdiagnose the etiology of the dysrhythmia), advised monitoring of all patients undergoing surgery and suggested the availability of an emergency
"crash" cart equipment in all situations. Indeed it is now evident that this complication occurs in an eclectic array of situations and everyone operating in the head and neck region must be aware of this.
JOHN D. LANGDON
DAVID W. MACPHERSON
References
1. KARABOUTA I. Increasing the articular eminence by the use of blocks of porous coralline hydroxylapatite for treatment of recurrent TMJ dislocation. J CranioMaxillo-Fac Surg 1990: 18: 107-13. 2. NORMANJ E DEB,BRAMLEYP. A textbook and colour atlas of the temporomandibular joint. London: Wolfe Medical Publications 1990: 136-50.
ALAN MATARASSO
New York, USA Comment from Dr. Precious:
Our current experimental design does not include as one of the purposes, to determine the extent of tissue stretch-traction that causes severe bradycardia in maxilloracial surgery. In our published study we found an incidence of either asystole or severe bradycardia in only 1.6% of 502 patients, all of whom had general anesthesia. This very small number of patients practically precludes the addition of a variable which, in any case, would be extremely difficult to measure. D. S. PRECIOUS Halifax, Canada
tunate choice of illustration. The authors would like to stress that in the 24 cases now treated by this technique not one has been complicated by an "unstable result". We have indeed addressed the medial extent of the osteotomy and do not use vertical eminotomy to limit it. Once the horizontal osteotomy has been commenced with a fissure burr to a depth of 1 cm, or a little more, a fine osteotome is driven into the osteotomy until the note of mallet/osteotome contact changes, signifying contact with dense bone in the region of the temporosphenoid suture. A sharp twist then completes the down-fracture. We have never had a problem with this technique and would suggest that the osteotomy created in this manner extends further medially than would be the case if it were limited by vertical eminotomy. We have not found it necessary to perform rigid fixation of either the down-fractured eminence or interpositional graft and use only tight periosteal closure with vicryl or PDS. In our experience recurrent subluxation/dislocation tends to be a bilateral problem if not at initial presentation certainly at a later stage in the natural history of the condition. In view
of the minimal morbidity of our technique it seems sensible to augment eminences bilaterally at one operation rather than submit the patient to two separate procedures. There should be no need for us to stress that cases should be assessed individually. Meticulous attention to haemostasis, the absence of temporalis muscle-splitting and limited dissection of tissue planes, obviates the need for vacuum or other types of surgical drainage or for that matter pressure dressings. Once again, cases should be assessed on their merits. There may be complications with drains and their indiscriminate use is to be deplored. The Dautry operation must involve increase in height of the eminence for surely if the "osseous buttress" referred to is to lie anterior to the condyle it must lie on the eminence which also lies anterior to the condyle. If it lies on the eminence then it must augment eminence height to some degree. Examination of a dried skull will confirm this point. It is because the "osseous buttress" so frequently fails to augment eminence height where it matters, that is medially, that the procedure is so unreliable. The authors would refer Mr. Mitchell
to the paper by Karabouta 1. She describes the use of Interpore 200 as an augmentation material. Similarities to the procedure we describe include: lack of vertical eminotomy, avoidance of rigid fixation, and no surgical drainage. We should point out that this paper was published after submission of our paper. Finally, we suggest that Mr. Mitchell and his senior colleague try our procedure. We are confident that he will find it an improvement on his current operation for temporomandibular joint hypermobility. After all, the proof of the pudding is in the eating. NICHOLAS M. WHEAR
I read with interest the article by Drs. Precious and Skulsky: "Cardiac dysrhythmias complicating maxillofacial surgery" (Int J Oral Maxillofac Surg 1990: 19: 279-82). The oculocardiac reflex is a similar phenomenon that has been extensively reported and is well known to ophthalmologists and anesthesiologists alike when undertaking surgery on the globe. I recently reported a 25% evidence of the OCR (25 of 100 prospectively studied patients) occurring in aesthetic blepharoplasty surgery. In that series a reflex prone patient was identified as: an anxious female (the sex may reflect the sample population) with some cardiac history (including elevated BP) having surgery under sedation and local (not general) anesthesia, and OCR occurring during traction on the eyelid fat pads. As Drs. Precious and Skulsky determined, we also found similar types of dysrhythmias, treatment requirements,
and that the OCR occurred while stretching tissue. It will be enlightening to review their ongoing prospective study in view of the inherent drawbacks that a retrospective study has; particularly when looking at a transient intraoperative event that may not be routinely recorded on a medical chart. Unlike our study it is feasible that the authors will have the opportunity of determining the extent of stretch-traction, (based on the amount of tissue advancement) that causes the cardiac dysrhythmias during maxillofacial surgery, providing additional valuable information. Due to the increasing incidence of ambulatory and office-based surgery we concluded that: awareness of this potentially fatal complication is important (and not to misdiagnose the etiology of the dysrhythmia), advised monitoring of all patients undergoing surgery and suggested the availability of an emergency
"crash" cart equipment in all situations. Indeed it is now evident that this complication occurs in an eclectic array of situations and everyone operating in the head and neck region must be aware of this.
JOHN D. LANGDON
DAVID W. MACPHERSON
References
1. KARABOUTA I. Increasing the articular eminence by the use of blocks of porous coralline hydroxylapatite for treatment of recurrent TMJ dislocation. J CranioMaxillo-Fac Surg 1990: 18: 107-13. 2. NORMANJ E DEB,BRAMLEYP. A textbook and colour atlas of the temporomandibular joint. London: Wolfe Medical Publications 1990: 136-50.
ALAN MATARASSO
New York, USA Comment from Dr. Precious:
Our current experimental design does not include as one of the purposes, to determine the extent of tissue stretch-traction that causes severe bradycardia in maxilloracial surgery. In our published study we found an incidence of either asystole or severe bradycardia in only 1.6% of 502 patients, all of whom had general anesthesia. This very small number of patients practically precludes the addition of a variable which, in any case, would be extremely difficult to measure. D. S. PRECIOUS Halifax, Canada
