CASE HISTORY
In July 2018, a 51-year-old male was referred to the Department of Oral & Maxillofacial Surgery of the Salvador Hospital, Santiago, Chile. In the clinical history the patient did not present any comorbidities or prescribed drugs, however a long history of substance abuse like alcohol, cocaine, cannabinoids, crack and tobacco was present. About his surgical history, in 2016 the patient suffered a mandible fracture which was surgically fixated.
When he arrived into the Salvador Hospital, he presented an active submandibular cutaneous fistula and left deviation of the jaw. Intraorally, poor hygiene, severe maxillo-mandibular discrepancy and malocclusion were found. Both, posterior crossbite and the dental midline deviation were on the left side due to a shortening of the mandibular body in the premolar area. In maximal intercuspation, only left posterior molars were in contact (Figure 1. A-E). A Computed Tomography (CT) was requested, where an extended bone loss was observed around the left canine and molars. Also a non-fixated plate could be seen in the same area (Figure 2. A-C).
The diagnosis was a suppurative osteomyelitis that went from the left mandibular canine to the second molar of the same side. An extensive surgical cleaning, together with the extraction of the affected bone, teeth and plate were performed. Two new reconstruction plates, 2.0 and 2.4 profile (Trauma One, ZimmerBiomet. Santiago, Chile), were used to stabilize the remaining mandibular segments (Figure 3. A-C).
The patient returned in August 2019 complaining of mandibular pain. He reported self removal of a loose metallic fragment inside his oral cavity. The patient presented a loosen reconstruction plate that broke through the oral mucosa and the skin of the chin. Also alteration of the mandibular dynamics was observed, caused by a lack of stabilization between the remaining mandibular fragments. (Figure 4. A-B) A new CT showed that only the distal part of the broken 2.0 plate remains and only the posterior part of the 2.4 plate was fixed to the bone. Loss in the contour of the mandible was evidenced both clinically and radiographically. (Figure 4. C-D)
Due to the extensive bone loss, instability of the mandible and acute symptoms of the patient, it was decided to remove both reconstruction plates, perform surgical cleaning and placement of four external fixations for two months (Kanhui, Empresa Tecnomedical, Santiago, Chile). Two external fixations were placed in the mandibular body of the unaffected side and the remaining two in the left side, more specifically in the condyle and ramus. (Figure 5. A-B)
During these two months, the DICOM file of a new Computed Tomography (TC) was transformed to a SLT archive in the free access software for virtual surgical planning 3DSlicer version 4.10.2. The metallic artefacts (external fixators) were virtually removed and the bone defect was virtually reconstructed. Within the software, the bone anatomy was mirrored to the unaffected side, allowing a virtual reconstruction of the bone loss segment. Also, the affected ramus was mesially repositioned into the glenoid fossa and segments were modified to reestablish the dental midline (Figure 6. A-C). The final virtual model was materialized in the 3D printer (Form 2, Formlabs, Somerville-Massachusetts, USA) to allow the extraoral preformation of a 2.4 surgical plate (Kanhui, Empresa Tecnomedical, Santiago, Chile) and estimate precisely the measure of the iliac crest graft. (Figure 6. D-I)
Following the virtual surgical planning, the patient was hospitalized and prepared for surgery. Both procedures, anterior iliac crest graft removal and the mandibular reconstruction were performed in one operatory step. (Figure 7.A) For the mandible reconstruction, skin incisions in the base of the mandible and osteomyocutaneous flaps were made to expose the remaining mandibular bone. Limited resection of the irregular bony margins of the defect were made to provide an optimal graft-mandible interface. (Figure 7.B). The already preformed surgical plate was placed and fixed in sequence for optimal adaptation. (Figure 7.C). The preformed iliac crest graft combined with Adbone TCP 3 – 4 mm particulate Xenograft (Kanhui, Empresa Tecnomedical, Santiago, Chile) were placed in the defect and fixed to the plaque with pins located 1.5 cm apart from each other (Figure 7.D-E).
After the surgery, the patient stayed in the hospital 10 days, with strict hygiene of the skin in the postoperative period and pharmaceutical therapy of 600mg Clindamycin each 8h and 1g Ceftriaxone every 24h, both intravenous for the first 4 days and only 300mg oral Clindamycin every 8h for the next 14 days. He was called for control two weeks after leaving the hospital but he did not attend and returned after 3 months instead, where a clinical examination was performed and a control CT was requested. In the extraoral exam there was still some residual post-surgical inflammation, nevertheless a tendency to facial symmetry is appreciated and the scar and soft tissue are healthy and esthetically suitable (Figure 8. A-B). Intraorally no signs of periodontal disease, halitosis, erythema or suppuration were found, the oral mucosa was healthy, symmetrical dental midline, Angle’s molar Class I with Class I canine relationship in the left side was achieved (Figure 8. C-D). The mandibular dynamic was asymptomatic with acceptable mandibular range movement and suitable oral functions according to the patient. Regarding the control CT, the graft was successfully preserved and the plaque maintained the proper mandibular arch relationship. (Figure 9. A-D)