Long-Term Outcomes and Growth Analysis of Costochondral Grafts for Hemifacial Microsomia: 24-Year Experience of a Single Surgeon

Background: Costochondral grafts (CCGs) can be used in mandibular reconstruction of Kaban-Pruzansky IIB/III hemifacial microsomia (HFM). Their growth is variable, occasionally necessitating secondary surgery. This study examined one surgeon's 24-year experience to better quantify long-term outcomes and surgical care required in CCG reconstruction of HFM mandibles. Methods: Serial 3-dimensional computed tomography scans, from preoperative to most recent, were analyzed in patients with a minimum of 4 years of clinical follow-up after CCG reconstruction. Graft/ramus height, length, volume, bilateral mandibular body length, and chin deviation were measured. Changes in measurements were analyzed preoperatively, immediately postoperatively, at the most recent imaging before secondary surgery, and at the most recent imaging overall. Growth rates per measure were calculated using scans after CCG but before secondary surgery. Results: Thirteen patients were analyzed. Median (SD) clinical follow-up was 10.0 (5.1) years. One patient developed temporomandibular joint ankylosis secondary to stacked-graft malposition, which was repaired without further complications. CCG reconstruction led to immediate improvement in graft/ramus height (P = 0.03), length (P = 0.002), and volumetric symmetry (P = 0.02). No difference was found between graft and native ramus height (P = 0.4) or length measures (P = 0.5), whereas graft volume and the affected mandibular body grew significantly more slowly. According to the latest imaging, 63% of patients required secondary surgery, including distraction osteogenesis or orthognathic surgery, due to differential graft or hemimandible growth behavior. Based on the most recent clinical follow-up, this proportion increased to 93%. Conclusions: CCGs provide significant short-term mandibular and facial symmetry improvement in HFM IIB/III. Long-term analysis reveals frequent undergrowth requiring secondary intervention to promote and maintain symmetry. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.