Oral Cutaneous Fistulas Workup

Updated: Mar 03, 2022
  • Author: James E Cade, DDS, FACD; Chief Editor: William D James, MD  more...
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Imaging Studies

In chronic periapical infections, a well-circumscribed radiolucency may be observed radiographically; however, in early infections, radiographic evidence may not be observed.

On radiographs, osteomyelitis appears as an area of radiolucency, radiopacity, or mixed radiolucency with poorly defined borders. The mandible is most commonly involved. These findings are also present in osteoradionecrosis

Unless the infection is rampant and severe, imaging studies such as a CT scanning or MRI usually are not necessary. If infection persists despite therapy, CT scanning and MRI may be necessary to determine its extent and to rule out a neoplastic cause. Computer-aided rapid prototyping in a 3-dimensional format with CT scans was reported to analyze each tooth root to aid in nonsurgical root canal therapy. [43]

Panoramic radiographs, lateral jaw plain radiographs, Waters radiographs, or periapical radiographs may be necessary for diagnosis and treatment, depending on the location and extent of the infection.

Cone-beam studies may be very beneficial for the diagnosis of dental infections. This technique is excellent to find the exact origin and extent of the infection. More dental offices, and especially oral and maxillofacial surgeons' offices, use cone-beam technology for the following [44] :

  • Dental implant placement and evaluation of adequate bone with anatomic structures
  • Evaluation of the temporomandibular joints for an aid to diagnoses of temporomandibular disorders
  • Examination of teeth and facial structures for orthodontic treatment planning
  • Evaluation of extraction of mandibular third molars and the proximity of the inferior alveolar nerve
  • Evaluation of teeth and bone for signs of infections, cysts, or tumors

With oral antral and oral nasal fistulas, cloudy sinuses may be observed on panoramic or Waters radiographs. Radiographs occasionally show a break in the antral or nasal floor. If the opening to the palate is large enough, nasal speech occurs.

CT fistulography can be used to help diagnose an orodentocutaneous fistula of dental origin. [45]  Sodnom-Ish et al reported success identifying 2 cases of odontogenic cutaneous sinus tracts by using CT with the soft tissue window setting. [46]



Histologic Findings

With acute infection, histologic sections show a preponderance of neutrophils and necrotic debris. Chronic infections are histologically characterized by numerous plasma cells, lymphocytes, and macrophages; often, a proliferation of blood vessels and connective tissue or granulation tissue is present.

In chronic osteomyelitis, sections of acellular bone are present, sometimes with little inflammatory infiltrate. When histologic sections are processed, decalcification of the specimen for sectioning can remove lacunar cells present in bone. This effect must be considered when histologic sections of bone are viewed.

Actinomycosis has characteristic pseudohyphae appearing as clublike projections that stretch out from a central basophilic-staining core. The absence of this finding does not rule out an actinomycotic infection.

Microscopic sections of mucoceles show minor salivary glands with chronic inflammation and a granulation wall that surrounds a pool of mucin.