J Oral Maxillofac Surg 55:747-750, 1997 Dissecting Aneurysm of the Internal Carotid Artery After a Mandibular Osteotomy HIROYUKI SUZUKI, DDS, PHD,” ETSURO SAITO, AND KENJI HASHIMOTO, MD, DDS, PHD$ was 170 minutes there were no major intraopcrativc complications, and the initial postoperative course was uneventful. Sagittal split ramus osteotomy (SSRO) of the mandible is widely practiced procedure for correcting jaw deformities. Behrman’ reported that the most commonly encountered complications were relapse, hemorrhage, trauma to the mandibular nerve, edema, fracture of the ramus, necrosis, sequestration of bone, and infection. Neurologic complications, including inferior alveolar nerve hypesthesia and anesthesia and facial nerve injury, also have been known to occur. Cerebral infarction caused by a dissecting aneurysm of the internal carotid artery after SSRO of the mandible is very rare. Report About 20 hoursafter the operation,the patientcomplained of headache. It was regarded as a migraine the operation, she became drowsy and did not respond to verbal commands (Glasgow Coma Scale; E3 M6 VA). Physi- cal examinationshowedthat the blood pressureand pulse rate were normal. A left carotid bruit was heard. Cranial nerve examinationshowedthat shehad a right facial palsy. The pupils were asymmetric,with the left smallerthan the right, later believed to be a Horner’s of Case of Oral and Maxillofacial syndrome. Motor nerve examination showed right hemiplegia. Becauseof these findings,a presumptivediagnosisof a cervical carotidinjury was made.A Babinski sign was not observedon the right side. Bilateral carotid cerebral arteriography via the femoral artery was performedemergently.The angiogramshoweda filling defect in the left internal carotid artery about 2 to 3 cm above the bifurcation, and extendinginto the cavernous portion (C4) of the vessel. The angiogram was suggestive of a dissecting aneurysm of the left internal carotid artery (Fig 1) and therefore, intra-arterial infusion of Urokinase (960,000 IU) was performed immediately. After about half an hour of urokinase therapy, brisk bleeding from the bilateral operated area was encountered. A pressure pack was placed between the proximal and distal fragments and, after that, the patient was intubated. An hour post-therapy, a repeated angiogram showed mild recanalization of the left internal carotid artery (Fig 2). She was left intubated and transferredto the intensive care unit (ICU). Next morning shewasextubated, and computed tomography (CT) was performed with contrast medium.Left putaminalhemorrhage wasdetected(Fig 3). On March 1 (1lth postoperativeday), shewastransferred to the neurosurgeryward. Within a month of the occurrence, there was a gradual resolutionof her right hemiplegia.In April shewasdischargedfrom the hospital.One year later, the patienthadonly a minimalright upperextremity paresis. Received from the Department of Oral and Maxillofacial Surgery, Hamamatsu University School of Medicine, Hamamatsu-city, Shizuoka Prefecture, Japan. * Assistant Professor. t Resident. $ Professor. Address correspondence and reprint requests to Dr Suzuki: Department of Oral and Maxillofacial Surgery, Hamamatsu IJniversity School of Medicine, 3600 Handa-cho Hamamatsu-city, Shizuoka Prefecture, 43 1-31 Japan. Association headache and an anodynewas administeredto her. Twenty-nine hours after A 25-year-old Japanese woman was referred to the department of oral and maxillofacial surgery at Hamamatsu University Hospital for surgical correction of her prognathism. In profile, there was mild protrusion of the lower lip. Preoperative cephalometric measurements included an SNA of 87.3” and an, SNB of 83.5”. It was determined that the patient should undergo bilateral SSROs of the mandible to correct the skeletal Class III profile. She was admitted to the hospital on Febmary 14, 1994. On admission, her vital signs were normal and the results of the general physical examination were also within normal limits. The operation was performed on February 17, 1994, under general anesthesia. Bilateral SSROs were performed using the Obwegeser-Dal Pont method. The mandible was retruded approximately 5 mm and titanium miniplate fixation was placed. Postoperative maxillomandibular fixation was not used. The operation time 0 1997 American DDS,t Discussion Injuries to the internal carotid artery are a wellknown complication of maxillofacial trauma2*3but arc a rare complication aI”ter orthognathic surgery.4 Injuries to the internal carotid artery during orthognathic Surgeons 0278-2391/97/5507-0013$3.00/O 747 748 ANEURYSM AFTER A MANDIBULAR OSTEOTOMY FIGURE 1. A carotid angiogram showing a filling defect distal to the bifurcation of the left internal carotid artery extending into the cavernous portion. A, Lateral view, B, frontal view. SUZUKI, SAITO, AND HASHIMOTO FIGURE 2. A carotid angiogram after urokinase therapy showing slight recanalization of the left internal carotid artery. FIGUl iE 3. Computed gram after urokinase showil lg left putaminal rhage. tomotherapy hemor- 749 750 surgery can be direct or indirect and can occur anywhere from the bifurcation of the carotid artery in the neck to intracranially. Lanigan4 has shown that a direct injury to the carotid artery can occur after a skull base fracture in the area of the carotid canal or foramen lacerum. Anatomic variations of the base of the skull, such as incomplete ossification or bony defects in the vicinity of the cavernous sinus, can occur and can place the intrapetrous portion of the carotid artery in peril when maxillary orthognathic surgery is performed. Indirect injury, the most likely mechanism, is due to a sudden forceful stretching of the internal carotid artery in the neck over the upper cervical spine by cervical hyperextension and contralateral rotation of the head. In the literature, there are some reports of aneurysms of the carotid artery after orthognathic surgery, and almost all of these occurred as a complication of Le Fort I osteotomy.5-7 After SSRO, there are two reports of a carotid arterial pseudoaneurysm and occlusion,g but a dissecting aneurysm of the carotid artery after SSRO has not been reported previously. In this case, although a definite cause cannot be established, the following are possibilities: 1. Direct trauma to the left internal carotid artery caused when the mandibular ramus was moved posteriorly 2. Direct trauma to the left internal carotid artery by an osteotome or Obwegeser Haken Retractor 3. Indirect trauma due to cervical hyperextension and contralateral rotation of the head Contralateral rotation of the head at the atlantoaxial joint stretches the artery and, in addition, causes rota- ANEURYSM AFTER A MANDIBULAR OSTEOTOMY tion of the ipsilateral mass of the atlas anteriorly, forcing it against the artery. If both hyperextension and rotation occur in combination, it could cause impingement of the bone on the artery, resulting in acute local compression and stretch, and an intimal tear.4 This finding in this case suggests that the surgeon who performs a mandibular ramus split osteotomy should give consideration to protection of internal carotid artery to avoid direct trauma to it, and that good head position for the patient must be ensured and cervical hyperextension with contralateral rotation of the head must be avoided. References 1. Behrmann SJ: Complications of sagittal osteotomy of the mandibular ramus. J Oral Surg 30554, 1972 2. Silvernail WI, Croucher DL, Byrd BR, et al: Carotid artery injury produced by blunt neck trauma. South Med 68310, 1975 3. Robinnson NA, Flotte CT: Traumatic aneurysms of the carotid arteries. The American Surgeon 123, 1974 4. Lanigan DT: Injuries to the internal carotid artery following orthognathic surgery. Int J Adult Orthodont Orthognath Surg 3:215, 1988 5. Otterloo JJ, Tuinzing DB, Greebe RB, et al: Irma- and early postoperative complications of the Le Fort I osteotomy. J Craniomaxillofac Surg 19:217, 1991 6. Lanigan DT, Hey JH, West RA: Major vascular complications of orthognathic surgery, hemorrhage associated with Le Fort I osteotomies. J Oral Maxillofac Surg 48561, 1990 7. Yeo JF, Loh FC, Egyedie P, et al: Serious circulatory disturbance after Le Fort I osteotomy: A case report. J Craniomaxillofac Surg 17:222, 1989 8. Mercier J, Delaire J: Osteotomie sag&ale des branches montantes de la mandible. Rev Stomatol Chir Maxillofac 2:94, 1984 9. Sanni K, Campbell R, Rosner M, et al: Internal carotid arterial occlusion following mandibular osteotomy. J Oral Maxillofac Surg 42:394, 1984