Background: Donor-site deformity may complicate autologous costal cartilage harvest for microtia reconstruction. This is reportedly prevented by total subperichondrial costal cartilage harvest, costochondral growth center preservation, donor-site reconstitution with morselized leftover costal cartilage, and perichondrial repair (Kawanabe-Nagata method). However, no quantitative assessment of preoperative versus postoperative thoracic morphology exists following use of this method.
Methods: Twenty-five consecutive patients (11 adult and 14 growing patients) who received radiographic donor-site evaluation for autologous unilateral primary microtia reconstruction were studied. Each underwent thoracic three-dimensional computed tomography preoperatively and 6 months postoperatively. The authors quantified (1) donor-site skeletal deformation with respect to the sixth to ninth costochondral junctions (2) and distortion in thoracic/hemithoracic Haller indices. The contralateral unoperated hemithorax provided intrapatient control data.
Results: Statistically significant deformations occurred in the sagittal and transverse planes in growing patients and in the transverse plane in adults, with respect to most costochondral junctions on operated versus unoperated sides. Importantly, in growing patients, the sixth to ninth costochondral junctions on the operated side failed to descend postoperatively with normal growth in the vertical plane, unlike on the unoperated side. However, no gross distortions in thoracic/hemithoracic proportions occurred according to Haller indices.
Conclusions: Despite meticulous donor-site management and reconstruction according to the Kawanabe-Nagata method, patients sustained significant localized skeletal deformations, as quantified by three-dimensional computed tomography, the configurations of which differed according to whether patients were adult or growing when operated on. Whether these improve or worsen in the long term, particularly in growing patients, requires confirmation.
Clinical question/level of evidence: Therapeutic, III.