Early Versus Late Improvement in Cephalic Index After Endoscopic Assisted Sagittal Craniosynostosis Repair With Postoperative Cranial Molding Orthosis

Introduction:  Minimally invasive endoscopic techniques for the treatment of sagittal craniosynostosis have been shown to achieve excellent long-term outcomes.  The objective assessment of calvarial reconfiguration centers on serial measurement of cephalic index.  Limited objective information is present in the literature about changes in the cephalic index over the course of postoperative helmet therapy. Our primary objective in this retrospective case series is to quantify this change in cephalic index, with secondary objectives intending to show that the rate of cephalic normalization decreases further from surgery irrespective of other variables.

Methods:  We analyzed data from 7 cases of primary sagittal craniosynostosis treated with endoscopic wide vertex craniectomy and biparietal wedge osteotomies performed at our institution between 2012-2013 in infants aged 3-6 months.  Each patient’s cephalic index was quantified using pre- and postoperative STAR scanning over the course of up to one year. We compared changes in cephalic index one week after surgery to the rate of change further from the operation using t-test analysis. 

Results:  Although patient compliance with STAR Scan was not consistent, (range of 3- 6 STAR Scans per patient) the immediate postoperative difference from surgery to first (1 week) STAR Scan was significant. In comparison to the total change, 33% of cephalic index normalization occurred during this one week period versus the rest of the year (average change of 0.0436). In fact, 4 months after surgery little to no change in cephalic index occurred. At the conclusion of the study, all patients noted normalization of cephalic index (range of 0.76-0.81). 

Conclusions:  The majority of improvement in cephalic index occurs most rapidly after initial surgical intervention, consistent with observations at other institutions. This change is noticeably visible on the operating room table, and quantifiable at initial STAR scan. Change occurs throughout helmet therapy, but at a slower rate of change further from surgical intervention with plateau at 4 months. All patients achieved normalization of cephalic index. 

We intend to investigate the factors that may account for the decreasing rate of change during the treatment period, including socioeconomic barriers, parental compliance with the helmeting regimen, and recognized patterns of physiological head growth. 

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