rteriovenous malformations (AVMs) are rare vascular lesions, especially in the maxillary sinus. Congenital AVMs are generally asymptomatic and remain quiescent until puberty. They are thought to be the result of errors in vascular morphogenesis or the result of trauma. AVMs are complex vascular lesions that require a multidisciplinary approach. Clinical symptoms can include spontaneous bleeding, life threatening hemorrhage, insidious facial swelling, asymptomatic facial growth, blurred vision, pain (described as tender to pulsating or throbbing), numbness, angiomatous discolorations, infections and bruits. In this case, the only clinical symptoms were slight mobility of the upper left primary second molar and slight swelling of the cheek. Radiographic evidence showed the appearance of a radiolucency around the crown of an upper left second bicuspid.
Histology and Literature of AVM’s
The development of AVMs can be described in three stages:1 the endothelial stage, rete form stage and gross differentiation stage. The endothelial stage is characterized by the formation of endothelial lakes. In the rete form stage, the meshwork differentiates or coalesces into capillary channels, some of which develop into muscular coats. The last stage is the gross differentiation stage. Rappaport and Yim1 have postulated that interruption in the development of these stages results in specific abnormalities. Interruption of the rete form and in the gross differentiation stages results in micro-macro fistulous malformations.1 Rapport and Szilagi2 describe the failure of morphogenesis during the stages of embryonic vascular formation. This is a failure to progress from the endothelial growth stage, when there is a capillary channel communication developed between the lakes, to the differential stages, when the muscle-sheathed channels become arteries and unsheathed channels become veins. According to Malan and Azzolini,3 a hemodynamic syndrome develops, which affects all levels of circulation. This includes efferent veins and collateral venous circulation, heart and afferent arteries and collateral arterial circulation. As the development of the AVM progresses the end result is the increase in shunting, caliber and flow of the AVM. This results in a viscous cycle causing an increase in the size of the AVM.3 The growth of the AVM is not due to cellular proliferation, which is typical of most tumors. It is due to the dilated blood vessels maintained by the hemodynamic condition at the levels of the malformation.4,5 It is also relevant that the existence of vascular malformations should not be surprising, due to the fact that the embryological vascular system is formed rapidly within a 20-day framework.3 Coleman6 notes that microscopic arterial venous connections that occur embryonically persist and signs and symptoms of direct vascular shunting may appear. AVMs may not be present at birth, but become affected by pleiotropic stimuli such as endocrine changes, trauma, infection or vasoactive disturbances that may allow inactive channels to fill with blood.1,7 Malan and Azzolini3 suggest that the AVM is transformed from an inactive arteriovenous fistula to an active aggressive lesion, which may contain angioblasts, by responding to a hemodynamic stimulus. Others8 believe that all AVMs are congenital or present from the time of birth. Under normal circumstances blood is carried from arteries into capillaries and then blood is returned to the heart by veins. In AVMs, arteries carry blood directly to the veins bypassing any capillaries creating a shunt of blood flow.9
A nine-year, seven-month old Caucasian female was brought to the dental office on February 8th, 1993 as an emergency because her upper left second primary molar was mobile and there was a slight swelling of the left cheek. Clinical examination revealed M1 mobility of the upper left second primary molar. The upper left first primary molar and the upper left first permanent molar exhibited no mobility. There was localized gingival irritation around the upper left first primary molar, the upper left second primary molar and the upper left permanent molar. There was no pocketing around these teeth. A periapical radiograph (Fig. 1) showed the tooth was caries free and there was a radiolucency present around the crown of the unerupted upper left second bicuspid and within the root structure of the upper left second primary molar. There were no additional symptoms such as numbness, spontaneous bleeding, asymmetrical facial growth, widened periodontal ligament, tenderness or pulsating pain. Based on the symptoms and after radiographic examination, a provisional diagnosis of a follicular cyst was made because of the association of the radiolucency around the crown of the unerupted upper left second bicuspid.
FIGURE 1. Periapical Upper Left 2nd Primary Molar–February 8, 1993.
Follicular cysts can be found in children and adults. The patient was rescheduled for a post-operative visit in one week. At that visit on February 15th, 1993, the clinical examination revealed no bleeding on probing or pocketing. The slight swelling of the left cheek was not evident. What was noted at that visit was that there was an increase in mobility of the involved tooth. The upper left second primary molar had M3 mobility and the upper left first permanent molar had M1 mobility. At that visit, a panoramic radiograph was taken (Fig. 2). The panoramic radiograph showed that the upper right and left first and second primary molars were in the stages of exfoliation. The upper left second bicuspid appeared to have more of a radiolucency on the distal aspect of the crown. The concern was the increase in the mobility of the teeth and the involvement of the upper left permanent molar. The parent was asked to return later that day so that the clinician could consult with a periodontist. After this consultation the decision was made to remove the upper left second primary molar. The patient was given nitrous oxide sedation to reduce anxiety and one 1.8ml carpule of two percent xylocaine with 1:100,000 epinephrine for local anesthesia. The upper left second primary molar was extracted. Immediately following the extraction the socket began to bleed uncontrollably. The high-speed suction system was unable to remove the volume of blood flowing out of the socket. The patient’s mouth was turned to the side so that blood would flow out of the mouth and prevent the child from choking or aspirating.
FIGURE 2. February 15th, 1993, panoramic radiograph.
Sterilized cotton gauze was placed and constant finger pressure was kept on the extraction site. A 10-year-old child has about four liters of blood. A loss of 40 percent or 1.6 liters would be fatal without fast help. The clinician estimated that the patient lost about 10 to 12 percent of her blood volume (1/2 liter of blood). All vital signs were normal. The dentist was able to control the blood flow coming out of the socket. The office called 911 and the Emergency Medical Services transferred the patient to the l
ocal hospital emergency room. Realizing the severity of the situation, the dentist felt it was important to stay with the patient to keep finger pressure on the gauze and talk to the child to ease her anxiety. Once at the hospital, the child was brought to the operating room where a general anesthetic was administered to evaluate the problem. Great effort was made not to dislodge the gauze because the bleeding would continue and there was the possibility of hemorrhagic shock. It was determined that the patient would be transferred by helicopter to the Children’s Hospital of Philadelphia (CHOP) for evaluation.
Upon arrival at the CHOP, the patient was evaluated and it was determined that angiography and a CT scan were necessary to evaluate the maxilla. A catheter was inserted into the left femoral vein. The angiogram with subtraction studies showed that there was an intraosseous arteriovenous malformation of the left maxillary sinus. The angiogram (Fig. 3) showed the feeding vessels were from the internal carotid artery and the internal maxillary artery. An angiogram was done on the right side (Fig. 4) and it showed normal vascularity. The CT scan (Fig. 5) showed that the lesion eroded through the buccal plate. Due to the large size, high flow rate and location of the AVM it was determined that embolization would be used to block the feeding vessels.
FIGURE 3. February 15th, 1993, pre-embolization left side.
FIGURE 4. February 15th, 1993, right side normal.
FIGURE 5. CT scan shows erosion of buccal plate.
As shown in Figure 6, the initial embolization using poly-vinyl particles and wire rings appeared to have slowed the blood flow in the location of the AVM. The patient was kept in a medically induced coma so the packing would not be dislodged. The patient was scheduled for a left side hemi-maxillectomy with a Weber-Ferguson approach on February 17th, 1993. Seven hours before the patient was scheduled for the surgery, the gauze was removed and the socket was still bleeding profusely. Another catheterization was performed that demonstrated that the initial embolization was not effective, and the AVM still exhibited a high flow rate (Fig. 7). It was decided that sclerosing the vessels would be attempted by injecting 100 percent ethyl alcohol through a 19 gauge needle extra-orally through the cheek into the maxillary sinus. The left jugular vein was compressed for thirty seconds to stop venous flow. This would stop the high flow of blood into the sinus thereby providing sufficient time for the alcohol to remain within the sinus and sclerose the vessels. Figure 8 shows the post-operative angiogram after the ethyl alcohol was injected in the sinus. Six hours later, the patient was scheduled for a Weber-Ferguson hemi-maxillectomy. This procedure was averted due to the fact that when the packing was removed from the extraction site in the operating room, the bleeding had stopped. Packing and sutures were placed, and the patient was kept in the medically induced coma for two days. After two days, the packing was removed and hemostasis remained in the area of the extraction. The patient was awakened from the medically induced coma, and was discharged from the hospital the next day. Figure 9 shows a post-operative periapical radiograph taken on May 18th, 1993. The emboli can be seen in the radiograph. Figure 10 shows a post-operative periapical, a left bitewing and a panoramic radiograph from April 13th, 2000. The bone was filled in and the teeth have erupted. The patient has had orthodontics and her 3rd molars removed. Twenty years following the incident, the patient has had no recurrence or problems from the AVM.
FIGURE 6. February 15th, 1993, post embolization.
FIGURE 7. February 17th,1993, unsucessful first emolization.
FIGURE 8. February 17th, 1993, embolization after ethyl alcohol injection through the cheek.
FIGURE 9. Periapical radiograph showing emboli, May 18th, 1993.
FIGURE 10. Panoramic, periapical and bitewing radiographs, April 13th, 2000.
Arteriovenous Malformations (AVMs) are vascular abnormalities whereby there is a direct communication between the arteries and the veins bypassing the capillaries. AVMs can occur as a result of a trauma.10 AVMs are rare and there are very few cases reported. Persons with mandibular or maxillary vascular lesions are usually asymptomatic in the first decade of life. AVMs usually present during the second and third decades of life. In his review of the literature, Smith9 reported three deaths due to hemorrhage from AVMs. There is a 2:1 female prevalence and they are twice as common in the mandible as in the maxilla.11 Many AVMs exhibit clinical symptoms including asymmetrical facial growth, numbness, pain, spontaneous gingival bleeding in the molar area, palpable pulse, bruits, infection and mobile teeth. The case described above was atypical due to the fact that only two symptoms were present; slight mobility of the upper left second primary molar and slight swelling of the left cheek. Neither the periapical radiograph of the area nor the panoramic radiograph indicated the presence of an AVM. They both gave the impression that a simple odontogenic related dental issue was occuring. The only major complaint by the patient was a mobile tooth. Angiography through the femoral vein with subtraction studies showed a complex high flow AVM in the left maxillary sinus. The CT scan provided invaluable knowledge that the AVM was eroding the buccal plate. There are many modalities to treat vascular lesions. The treatments are embolization, irradiation, cryotherapy, resection, curettage and packing, obliteration, sclerosing agents and ligation of involved arteries. There are different kinds of emboli that can be used including: PVA beads (poly-vinyl particles), silicone, muscle, dura mater, gelfoam, autogenous thrombi, isobutyl cyanoacrylate, and detachable latex balloons.8,11,12 The choice made for the use of embolization depends upon whether or not the lesion is operable or inoperable. Complications of embolization include the following:
1. Passage of emboli into non-involved vessels;
2. Passage of emboli through the lesion;
3. Spasm of blood vessels;
4. Proximal arrest of the emboli;
5. Rupture of the vessels.8,11
Embolization blocks the contributing arteries. Major arterial ligation is reserved for most life-threatening situations because ligation presents problems when a lot of collateral feeders are present. The use of sclerosing agents is especially useful in areas where the lesion is inaccessible. The different kinds of sclerosing agents are sodium morrhuate, nitrogen mustard, ethyl alcohol, and boiling water. However, these are not always effective in high-flow lesions because of the rapid removal of the sclerosing agent. Radical resection produces severe bleeding and can create severe unacceptable facial deformities or disfiguration. Resection may be necessary because of the location of the collateral arterial feeder vessels and a chance of recurrence of the AVM after arterial ligation or embolization. According to Des Perz13 the more extensive the resection the more rapidly the collateral flow redevelops. The ischemic and anoxic peripheral cells bring about anatomic and physiologic demand to reestablish flow especially in the head and neck. After the resection the reconstruction should be accomplished with tissue transposed via soft tissue or a bone flap, with the idea that normally vascularized tissue will negate the need for development of collateral vascularization and provide alternative routes for other shunts. There are different opinions concerning the value of radical resection. In an effort to control afferent feeding vessels by ligation, sclerosing agents or embolization may actually increase collateral circulation.8 They believe the hemodynamic effect influenced by endocrine changes, vasomotor disturbances, and the development of collateral circulation explains why anything less than radical surgery in the high-flow macro-fistulous AVM’s can be doomed to failure.8 When comparing high-flow lesions and low-flow lesions, one notices that the high flow vascular malformations have a central area of low resistance vessels, which are supplied by numerous contributing arteries.14,15 The first embolization was not as successful as desired. A second attempt of embolization was performed and it was determined that 100 percent ethyl alcohol would be used to sclerose the vessels, because there are less side effects then using sodium morrhuate. The high-flow lesion presented problems because the ethyl alcohol could not remain in the area long enough to sclerose the bone. It was then determined that the left jugular vein would be compressed for 30 seconds to allow the ethyl alcohol to stay in the area of the feeding vessels and sclerose the bone. The area was packed after the second embolization. If the sclerosing of the vessels failed the patient would have required a Weber-Ferguson Hemi-maxillectomy. The concern was that the patient would exsanguinate on the table because of the erosion of the buccal plate. When the tissue was peeled away the patient would bleed out on the table. After the patient was wheeled into the operating room for the radical resection, the gauze and packing were removed and not a drop of blood appeared at the extraction site. The most recommended treatment is embolization and surgery, and with a successful transition from one treatment to the other hemostasis can be accomplished without exsanguination.
A case is reported of a life threatening previously undiagnosed AVM in a child for which there were only non-specified clinical dental symptoms and no significant radiographic evidence obtained. The subsequent management of the AVM using a multidisciplinary approach after the removal of a primary tooth is described. The initial life-saving treatment provided locally as well en route to a specialized facility was completed and sustained. The subsequent management of the AVM prevented the severe facial disfiguration and or exsanguination of the patient. This case report highlights the clinical appreciation of risk as it relates to silent and otherwise benign presentations of an unpredictable condition associated with routine procedures. It required a multidisciplinary approach for proper treatment and a long-term favorable outcome. Twenty years after the incident occurred the patient is still alive and well and a patient of record.
Why this paper is important to dentists?
• It gives a clinical appreciation of risk as it relates to silent and otherwise benign presentations of unpredictable conditions associated with routine procedures.
• When a life-threatening event occurs in the dental office a multidisciplinary approach is essential.
• Arteriovenous Malformations in the maxilla are very rare.OH
Dr. Donald Berger has been practicing dentistry since 1976 in Plymouth Meeting, Pennsylvania. Dr. Berger is a graduate of Temple University School of Dentistry (Kornberg School of Dentistry) and subsequently served i
n the United States Army for two years at Fort Gordon Medical Center, Augusta, Georgia. After leaving the military, he returned to Temple Dental School (Kornberg Dental School) and earned a degree in Pediatric Dentistry. In 1983 he became Board Certified by the American Board of Pediatric Dentistry, and also became certified by the American Society of Clinical Hypnosis. He was certified by the Institute for Graduate Dentists for Orthodontics in 1985. In 1988 he became a Professional member in the American Academy of Cosmetic Dentistry. He was the recipient of the American Dental Association Dentist Recognition Award in 1987 for Excellence in Dentistry.
Oral Health welcomes this original article.
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