Draining Orocutaneous Fistula Associated With a Failing Subperiosteal Implant: Report of a Case

Cutaneous sinus tracts and fistulization of the facial skin have a wide range of etiologies, the most common being odontogenic in origin.1 In the case of a failing subperiosteal implant, peri-implant tissues may become secondarily infected and may mimic an infection of odontogenic origin.1,^–8 Chronic infections associated with a failing dental implant can manifest into chronic diseases, such as peri-implantitis or extraoral/intraoral communicatory sinus tracts.7 For years subperiosteal implants were highly used in implantology, especially in patients with a severely atrophic alveolar ridge. Yet cases of their failure have been reported.6 We report a case of an orocutaneous facial fistula that was associated with a failing subperiosteal implant and was subsequently managed by removal of the failing hardware and primary closure of the fistula site.

A 51-year-old woman presented to our clinic in May 2003 with the chief complaint of swelling, pain, and a nonhealing draining fistula in the area of the right angle of the mandible. Her past medical history was unremarkable for systemic disease, medication use, or significant surgical or social history. The patient thought the pain and swelling were possibly associated with the placement of a subperiosteal implant in the bilateral mandibular molar regions in 1990. The patient reported being asymptomatic until 2000, when she noticed a gradually growing mass in the submandibular region. She became aware of this after multiple exacerbations and subsequent resolution of the swelling in the next 3 years. The patient denied seeking medical intervention until now. In 2003 the patient noted the development of a draining fistula in the right submandibular region. She reported the fistula had been increasing in size and became symptomatic; therefore, she decided to visit us for consultation in July 2003.

Extraoral examination revealed normal oral and maxillofacial structures, except for a purulent, draining wound, roughly 7 mm in diameter, surrounded by an edematous, erythematous area, approximately 20 mm in diameter, in the right submandibular region (Figures 1a and b). Intraoral examination revealed widespread erythema and edema associated with the entire length of the right buccal vestibule. In particular, edema was most prevalent with sparse mucosal drainage along the middle right buccal vestibule (Figure 2a and b). A draining sinus tract traveling from the oral cavity to the facial skin was identified. The infection appeared to be isolated to the buccal space and did not extend to the retromylohyoid region.

Upon panoramic examination, bone resorption was observed in the area surrounding the implant framework, particularly in the right posterior part of the implant (Figure 3). Clinically and radiographically, no connection appeared to exist between the mandibular bone and the framework of the implant, and the hardware appeared to be floating within the subperiosteal plane. An endoseous implant was noted in the maxilla. The maxillary subperiosteal implant will be addressed later in the patient's management scheme. The working diagnosis was a chronic infection that was attributable to a failing subperiosteal implant.

For palliative treatment of the infection, the patient was placed on a regimen of cefcapene pivoxil hydrochloride (100 mg, 3 times a day), cefotiam dihydrochloride (1 g, twice a day), and clindamycin phosphate (600 mg, twice a day). After consulting with the oral and maxillofacial surgeon who placed the mandibular subperiosteal implant, it was decided to remove the defective hardware and close the extraoral fistula by primary intention under general anesthesia.

The subperiosteal implant was removed in 2 separate pieces. Diffuse purulent exudate and granulation tissue were observed overlying the alveolar periosteum. An intraoral wound was found in the floor of the buccal vestibule. After debridement of the infected tissue by curettage and copious irrigation, the alveolar bone was smooth to instrumentation (Figure 4). The sinus tract, in toto along with the surrounding loose granulation tissue, was excised. Homeostasis and primary closure of the intraoral wound was obtained using full-thickness mucoperiosteal flaps. The facial wound was closed by primary intention.

Corrosion products and calculi sediments were observed overlying the metal framework of the removed hardware (Figure 5a and b). Elemental analysis revealed a mainly cobalt chromium alloy with some remnants of molybdenum, nickel, iron, and manganese. Stereomicroscopy examination displayed corrosion of the surface of the implant body and calcified dental sediments (Figure 6).

During the initial examination, it was observed that the maxillary subperiosteal implant was exposed, and the patient started to complain of pain in that region (Figure 7). The natural teeth of the anterior mandible pushed on the crowns of the maxillary implant, perforating the implant into the maxillary sinus. This required the patient to return for an additional procedure. The hardware was removed under intravenous sedation and local anesthesia in March 2004.

As seen in the explanted mandibular hardware, metal corrosion and calcified products were seen to be overlying the framework of the maxillary implant (Figure 8). An oroantral fistula developed after removal of the maxillary implant. This is being monitored because the patient's wished not to undergo any additional procedures. One-year follow-up revealed a healed wound and epithelialization in the area of the previous mandibular facial fistula (Figure 9a through c).

Mandibular subperiosteal implants were first used in the 1940s by Dahl.9 The first clinical reports in the United States were provided by Goldberg and Gershkoff,10,^–13 in which they wrote about a case series of subperiosteal implants for use in full mandibular restoration of the edentulous mandible. Using this method, an implant that fits the shape of the jaw is integrated into the subperiosteal layer of the alveolus and held in place by fibrous connection generated by the overlying periosteum. It is used in cases of an atrophic alveolar ridge and, unlike endosseous implants, virtually no bone height is needed for placement. The success rate of subperiosteal implants is higher in the mandible than maxilla.14^,15 Use of subperiosteal implants is contraindicated when the opposing teeth are natural, yet it is recommended when opposing another subperiosteal implant.14 Our patient had a mixed dentition—this may have contributed to the failure of the hardware.

Subperiosteal implants, although dwindling in use, have shown to be a successful treatment option for the edentulous dental patient. Following subperiosteal implant removal, reconstruction procedures are extremely difficult due to the extensive resorption and the adverse soft tissue changes of the alveolar ridge. Cobalt alloy, which was used frequently in the past in subperiosteal implant manufacturing, is associated with a higher corrosion rate in the oral cavity than other metals and is no longer used to fabricate subperiosteal implants. In the presence of infection caused by a failing subperiosteal implant, traditional antibiotic treatment may not suffice due to the underlying defective hardware still being present. We recommend immediate removal of the defective hardware with debridement and copious irrigation of the surrounding area followed by an antimicrobial regimen. If a cutaneous fistula is also present, it should be debrided, and primary closure should be accomplished.

We described a case of an orocutaneous facial fistula that developed secondary to a chronic infection associated with a failing subperiosteal implant. The defective hardware was subsequently removed and primary closure of the extraoral fistula was obtained, which resulted in alleviation of the patient's symptoms.

Michael Markiewicz and Kazuhide Nishiyama contributed equally to the first authorship of this article.