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Three-dimensional Treatment Outcomes of a Virtual Helmet Design Protocol for Sagittal Strip Craniectomy

Ramamurthi, Aishwarya BS; Hallac, Rami R. PhD; Kenyon, Laura E. BS; Thrikutam, Nikhitha BS; Warne, Christopher N. BS; Derderian, Christopher A. MD

Plastic and Reconstructive Surgery - Global Open: August 2019 - Volume 7 - Issue 8S-1 - p 55
doi: 10.1097/01.GOX.0000584520.49551.f7
Craniofacial Abstracts

UT Southwestern Medical Center, Dallas, TX

This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

BACKGROUND AND OBJECTIVE: Postoperative helmet therapy is commonly used after sagittal strip craniectomy. Helmet design must be customized to the surgical procedure and patient’s anatomy. This study compares 3-dimensional (3D) head shape outcomes obtained from a novel virtual helmet design protocol and a traditional helmet design protocol.

METHODS: This is an Institutional Review Board–approved, retrospective review of 24 patients who underwent extended sagittal strip craniectomy with wedge ostectomies performed by one surgeon and postoperative helmets produced by one orthotist. Traditional helmet design is based on STARscanner (Orthomerica) laser images with treatment goals indicated verbally by the surgeon. The virtual helmet design protocol utilizes images from a low-radiation protocol computerized tomography scan and 3D photograph (3dMD) obtained 1 week after surgery. An overlay of the 3D computerized tomography and 3D photograph is produced. Standardized views of the overlay were used to demonstrate the location of bone cuts in relation to the soft tissue landmarks and provide specific instructions from the surgeon to the orthotist. Eleven patients comprise the traditional helmet group (THG), and 13 patients comprise the virtual helmet group (VHG). Three-dimensional images were obtained preoperatively and at 1 week and 3, 6, 9, and 12 months postoperatively. Helmet therapy ended 12 months after surgery. Three-dimensional images of 24 age-matched healthy subjects were used as a control. The head was oriented on the Frankfurt horizontal plane, and cephalic index (CI) and vertical height (VH) measurements were recorded. Three-dimensional whole head composite images were generated for the VHG, THG, and control groups to compare global head shape outcomes to age-matched controls.

RESULTS: The mean CI before and after treatment was 72.39 (±4.37) and 81.07 (±3.37) for THG and 73.71 (±3.06) and 83.70 (±2.33) for VHG. The mean CI was 83.53 (±2.40) for controls. The difference in CI between THG and controls was significant (P < 0.05). The mean VH at the end of treatment was 122.88 mm (±4.78) for THG and 119.03 mm (±4.73) for VHG. Mean VH for controls was 118.27 mm (±4.26). The difference in VH between controls and VHG was not statistically significant, whereas the difference between THG and controls was statistically significant (P < 0.05). Three-dimensional analysis demonstrated normal biparietal and vertical dimensions in VHG compared to controls. THG exhibited narrower biparietal dimension and a greater vertical dimension compared to controls.

CONCLUSION: The VHG had a greater increase in CI and greater final CI compared to traditional helmet design. The 3D analysis demonstrated that global head shape outcomes of VHG had greater biparietal expansion and less vertical growth. VHG 3D head shape was comparable to normal controls, whereas THG head shape was slightly taller and narrower.

Copyright © 2019 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons. All rights reserved.