A New Approach for the Treatment of Unilateral Coronal Synostosis Based on Distraction Osteogenesis

Abstract

Sir: Multiple procedures have been described for the treatment of unicoronal synostosis; however, the large variation in technique highlights the fact that no single approach seems to alleviate all functional and aesthetic problems.1–5 The objective of this communication is to present our newly developed surgical approach for the treatment of unilateral coronal synostosis using an ultrasonic scalpel and distraction osteogenesis. This study was reviewed and approved by the Institutional Review Board of The Children’s Hospital of Philadelphia. Through a curvilinear coronal incision, subperiosteal elevation of the soft tissues on the affected side is undertaken as for conventional fronto-orbital advancement and remodeling. A coronal suturectomy is performed with the ultrasonic scalpel. After this, the ultrasonic scalpel is used to perform all cuts typical of a unilateral fronto-orbital advancement extending to the medial third of the contralateral orbit. Only the dura directly underlying an osteotomy is dissected, thus keeping the majority of the dura attached to the overlying frontal bone. Bone cuts include a vertical osteotomy contralateral to the affected side, just lateral to the midline, from the superomedial aspect of the contralateral orbit up to the anterior fontanelle. Inferior orbital cuts are then made along the orbital roof, taking care to avoid injury to the brain, the overlying dura, and globe. Additional radial osteotomies are made along the orbital roof to unfurl the horizontally short orbit (Fig. 1).Fig. 1: Intraoperative photograph of the technique. Note the radial osteotomies in the high frontal region and supraorbit. Also note the anterior and slightly inferior vector of distraction and bone bleeding.Through the most caudal portion of the suturectomy at the level of the pterion, malleable retractors allow for careful osteotomy of the greater and lesser wings of the sphenoid and the lateral orbital wall. Once these cuts have been completed, the affected frontal region is free to advance in all areas. A cranial vault distractor (KLS Martin, Jacksonville, Fla.) is then rigidly fixated to the midparietal region in the forehead with an anterior and slightly inferior vector, to translocate the orbital rim to its proper location (Fig. 1). Gelfoam (Pfizer, Inc., New York, N.Y.) is placed under the fixation screws to avoid injury to the underlying dura at that location. The distractor is activated to ensure completeness of the osteotomy and then returned to its original position. The scalp is then closed in layers. Distraction is started on the second postoperative day at a rate of 1 mm/day. The endpoint of activation is slight overcorrection of the orbital deformity. Figure 2 is a lateral radiograph of a patient who is entering the consolidation phase, which ranges from 8 to 12 weeks.Fig. 2: Postoperative lateral plain radiograph of a patient entering the consolidation phase. The forehead has been advanced approximately 27 mm.We have performed this procedure in two patients, both of whom have successfully completed the treatment course without complication. Estimated blood loss was approximately 200 cc in each case, approximately half that with conventional fronto-orbital advancement and remodeling at our institution. Both operative time and length of hospital stay were also cut in half. Figures 3 and 4 depict a patient before and after surgery. Disadvantages of the technique include need for a second operation to remove distracters, potential for dural tears, risk of hardware infection, and increased length of treatment.Fig. 3: Preoperative anteroposterior photograph of 4-month-old girl with right unicoronal synostosis.Fig. 4: Same patient depicted 4 weeks after surgery. Note improvement in frontal contour, orbital morphology, and brow position.In the short term, we have seen adequate correction of cranio-orbital dysmorphology without any ocular functional problems. We cannot report on the long-term advantages of this technique, but we hope it may allow for better bony growth with improved aesthetic and functional outcomes in the long run. ACKNOWLEDGMENTS This work was funded by the Department of Surgery of The Children’s Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania. PATIENT CONSENT Parents or guardians provided written consent for use of the patient’s images. DISCLOSURE The authors have no financial disclosures to report and no conflicts of interest to disclose. Jesse A. Taylor, M.D. Youssef Tahiri, M.D. J. Thomas Paliga, B.A. Division of Plastic Surgery Greg G. Heuer, M.D. Division of Neurosurgery Perelman School of Medicine at the University of Pennsylvania The Children’s Hospital of Philadelphia Philadelphia, Pa.