In hemifacial microsomia, patients with severely hypoplastic mandibles (Pruzansky type III) require replacement of the ramus and condyle unit. Common complications of this procedure include graft fracture and overgrowth of the graft. An uncommon case of osteolysis of the costochondral graft with osteitis of the middle cranial fossa is reported herein. To our knowledge, no such case has been reported in the literature previously. The aim of this report is to present the only known case and to discuss the contributing factors.
In hemifacial microsomia, patients with severely hypoplastic mandibles (Pruzansky type III) require replacement of the ramus and condyle unit. A costochondral graft is the best-known option for reconstruction of the ramus and temporomandibular joint (TMJ), because of further growth of the graft . The most common complications observed are graft fracture, rib graft failure, and under or overgrowth of the graft.
Osteolysis of the middle cranial fossa by a costochondral graft is an unusual event, with no case reported in the literature to our knowledge. We describe herein the case of a 6-year-old girl with otomandibular dysplasia who presented with osteolysis of the middle cranial fossa following a costochondral graft. The cause of this complication is discussed with reference to the literature.
A 6-year-old girl was referred to the department of maxillofacial and plastic surgery for treatment of left Pruzansky type III otomandibular dysplasia ( Fig. 1 ). Clinical evaluation showed a deviated chin, an occlusal cant, a scissor bite, and a maximal inter-incisal mouth opening of 27 mm. An orthodontic device was used preoperatively to counter the lateral deviation and to smoothly elongate the muscles to prevent postoperative contraction. Stereolithographic reconstruction (OBL, Châtillon, France) was used to evaluate the length, the outward angulation of the distal segment of the bone, and the angulation necessary for the reconstruction.
An under-correction was planned in order to prevent postoperative trismus and temporal fossa conflict. Ramus reconstruction with a costochondral graft was performed at the age of 6 years. A right seventh rib graft was harvested subperichondrally. The choice of chest side was guided by the further need for a left ear reconstruction. The perichondrium of the costochondral junction was preserved to maintain bone–cartilage connection for further chest growth. The length of the graft was 6.5 cm, including 13 mm of cartilage. According to the stereolithographic analysis, the graft length had been under-corrected by 10 mm. Intravenous prophylactic antibiotics were administered during and for 5 days after the procedure.
The bone graft was performed through an intraoral approach. A lateral vestibular incision was made along the external oblique line to the first left lateral incisors. A subperiosteal dissection was performed to expose the horizontal branch of the mandible. A tunnel was made towards the glenoid fossa with a non-traumatic fingertip dissection. The graft was then set in place with maximal bone contact between the graft and the mandibular horizontal branch (onlay technique). The recipient mandibular bone was abraded to prevent non-union. Osteosynthesis was performed with a 6-hole 2.0-mm titanium plate ( Fig. 2 ). At the end of the surgery, the surgeon did not note any conflict between the middle cranial fossa and the reconstructed ramus. Immediate postoperative evaluation showed restored facial symmetry (chin point in the facial midline) and a maximal inter-incisal opening of up to 30 mm. The surgical approach was closed in two interrupted suture layers. No maxillomandibular fixation was applied, but a bite guide was applied to achieve occlusal contacts.
On day 7, a minimal mucosa wound dehiscence was noted. Surgical exploration did not show any graft exposure, and closure was performed with a bioresorbable suture. At week 4, the patient presented with left mandibular localized cellulitis without trismus or scar disunion. On taking a history, the parents reported a cough; a physical examination was unremarkable showing a normal external auditory meatus. The patient was admitted and administered intravenous amoxicillin–clavulanic acid for 7 days. A craniofacial computed tomography (CT) scan revealed partial costochondral graft resorption and middle cranial fossa osteolysis without any plate fracture or screw loosening. The graft was lifted up into the middle cranial fossa without dehiscence of the dura. No intracranial pneumatocele, abscess, or haematoma was noted ( Fig. 3 A).
A multidisciplinary staff meeting involving maxillofacial surgeons, bacteriologists, paediatricians, and neurosurgeons led to the decision to remove the graft. Surgical exploration showed lost screws, osteitis of the graft, and total loosening of the cartilage. Pathological examination confirmed osteitis. Bacteriological cultures of the graft revealed a Streptococcus species infection sensitive to the antibiotics administered. Intravenous antibiotics were continued for 10 days, followed by a 6-week course of oral amoxicillin.
Close clinical and CT scan follow-up showed resolution of the infection and middle cranial base reconstruction. A year later, a multidisciplinary staff meeting considered a new reconstruction.
Preoperatively, bacteriological samples (skin, nose, and throat) did not show any pathological agent. A preoperative CT scan showed complete resolution of the infection and an intact cranial base ( Fig. 3 B). Prophylactic preoperative oral antibiotics (amoxicillin–clavulanic acid) were administered. The patient then underwent the same surgical procedure as described previously. The rib graft length was shortened (4 cm, including 20 mm of cartilage) to avoid any cranial base conflict. Postoperatively, a 7-week course of antibiotics (in accordance with the Streptococcus species antibiogram spectrum) was administered intravenously. No infection or osteitis occurred. Follow-up over the following 1 year was uneventful ( Fig. 4 ).