Abstract
The case of a patient with high-flow arteriovenous malformations (AVMs) affecting the mandible and lower face is presented. The patient had undergone surgical resection, sclerotherapy, and transcatheter embolization over the course of 16 years. As a result, all teeth except for the lower left third molar were missing, and a mass of arteriovenous malformed soft tissue covered the residual alveolar ridge. Implant placement surgery was performed in his mandible after treatment of the AVMs. Osseointegration of the implants placed in the mandible affected by the AVMs was evaluated. Rehabilitation in the absence of the alveolar ridge or keratinized gingiva was also evaluated. The implant stability quotient (ISQ) was measured before fabricating the restoration. An implant-supported partial denture was placed 4 months postoperatively. No implant failure was found; no bleeding on probing was present. The occlusion and masticatory function were satisfactory at 2-year follow-up. Osseointegration was safely achieved in the bone affected by the intraosseous AVMs that had been embolized. The success of an implant support prosthesis depends not only on the condition of the bony tissue but also on the surrounding soft tissue.
Intraosseous arteriovenous malformations (AVMs) are extremely rare morphological errors of vascular morphogenesis that, without appropriate treatment, can lead to life-threatening hemorrhage. Intraosseous AVMs account for about 1% of facial AVMs and represent the most severe vascular pathological condition in the head and neck. The gold standard treatment of AVMs is endovascular embolization followed by surgical excision. These lesions are often accompanied by severe hemorrhage and are associated with significant morbidity and/or mortality.
The case of a patient who received dental implant placement and denture rehabilitation after a series of treatments for AVMs is presented below.
Case report
A 52-year-old man who had received a series of treatments for AVM requested a lower denture. Sixteen years previously he had experienced occasional spontaneous hemorrhages at his lower gingiva. Two years later, a pulsatile exophytic mass was found within his chin. Angiography and computed tomography (CT) revealed an extensive high-flow AVM affecting the entire mandible, with significant feeding arteries from the ipsilateral internal maxillary artery, the facial arteries, and the contralateral lingual artery. A series of treatments ensued, including embolization with microcoils in the mandible on three occasions, six percutaneous absolute ethanol sclerotherapy treatments for soft tissue AVMs in the lower face, and two surgical resections. Necrosis of the facial skin and oral mucosa was recorded following the high dosage of sclerotherapy.
A congestive hypertrophic lower lip and chin was noticed upon extraoral examination. The soft tissues of the left lower buccal and lingual vestibule were swollen and pulsatile. The impacted left mandibular third molar was left in situ . Digital subtraction angiography (DSA) showed that the AVM lesions within the mandible had been embolized with the radiopaque microcoils ( Fig. 1 ). Transcatheter arterial embolization with microcoils was effective in shunting off the high vascular flow. However, high flow was noticed within the soft tissue overlying the left mandible ( Fig. 2 ).
Implant placement and oral vestibuloplasty surgery was performed under general anesthesia. Three SLA ITI osteointegrated implants (Straumann, Waldenburg, Switzerland) were inserted into the right mandible after raising a gingival flap. The torque range of the implants was from 10 to 35 N cm. The operation was uneventful, without profuse bleeding. A 1-mm thickness reabsorbed collagen membrane (Haiao, Yantai, China) was placed during the oral vestibuloplasty. Panoramic radiography was taken to identify the positions of the implants and for the determination of peri-implant marginal bone loss (MBL) ( Fig. 3 ). Cefradine (500 mg per day) was given for 6 days. The patient was advised to maintain good oral hygiene and to use 0.2% chlorhexidine mouth rinse, provided on prescription, for 14 days.
No early failures were observed on follow-up. The superstructures of the implants were fabricated 4 months after placement. The implant stability quotient (ISQ) value was measured using an Osstell instrument (Göteborg, Sweden) before the restorative procedures and at 2 years of follow-up ( Table 1 ). A partially removable overdenture with bar–clip attachment was fabricated ( Fig. 4 ). During the 2 years of follow-up, the following parameters were recorded: (1) Peri-implant bone absorption (MBL): this was assessed by radiography – mesial and distal – for each implant, using SIDEXIS XG software (Sirona, Germany). In order to make statistical comparisons, the mean MBL was calculated and recorded every 6 months; the mean MBL was 0.58 ± 0.16 mm. (2) Probing depth: four sites (mesial, distal, buccal, and lingual) were measured ( Table 1 ). (3) Stability and retention of the denture; this was found to be satisfactory. No implant failures or soft tissue bleeding was found. The patient’s masticatory function with the partial overdenture was satisfactory at the 2-year follow-up.
| Implant (proximal to distal) | Insertion torque (N cm) | Implant stability quotient (ISQ) | Probing depth (mm) | |||
|---|---|---|---|---|---|---|
| 4 months | 24 months | 4 months | 24 months | |||
| 1 | 35 | 77 | 62 | Mesial | 5.0 | 3.0 |
| Distal | 5.2 | 3.7 | ||||
| Buccal | 4.9 | 3.5 | ||||
| Lingual | 4.2 | 4.3 | ||||
| 2 | 10 | 72 | 82 | Mesial | 4.3 | 4.1 |
| Distal | 3.9 | 4.0 | ||||
| Buccal | 3.0 | 3.0 | ||||
| Lingual | 3.0 | 3.2 | ||||
| 3 | 25 | 76 | 71 | Mesial | 3.6 | 3.2 |
| Distal | 3.3 | 3.2 | ||||
| Buccal | 2.9 | 2.8 | ||||
| Lingual | 2.8 | 2.8 | ||||
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