Three-Dimensional CT Validation of Supraperiosteal Temple Volumization with Hyaluronic Acid Filler Techniques

Introduction: Temporal hollowing is one of the earliest signs of facial aging.  Fat and fillers are an effective method to treat the volume loss; however, the resultant anatomical location of filler is incompletely understood.^1,2  The purpose of this study is to assess topographic changes of temple contour, and examine the final anatomical plane of hyaluronic acid (HA) gel injected into the anterior temporal fossa of cadaver specimens, using a previously published "One Up, and One Over" technique, as well as derivative techniques.^3,4

Methods:  The study was composed of 2 groups of 4 hemifacial cadavers.  For group 1, iodinated contrast material was added to dyed HA gel mixture, and injected in a “One Up, and One Over” technique.  10cc of iodinated contrast was injected into each common carotid artery.  Following injection, a CT scan was performed to evaluate the location of the filler.  Three-dimensional reconstructions of the CT scan were performed with Slicer 4.8, a free access program available for DICOM file manipulation.⁵  For group 2, the HA mixture was injected in specific locations, using “Two Up, and One Over” and "One-and-a-Half Up, and One Over" from the junction of the temporal crest and lateral orbital rim.  All specimens were then dissected in a layered fashion to directly visualize relationships between the injected filler and temporal anatomy.  Topographic surface changes were assessed by pre- and post-injection 3-D photography.

Results: In group 1, CT scan imaging and dissection localized the HA gel to the deep and infra-temporal spaces. The filler tracked in a previously undescribed areolar layer along the anterior surface of the temporalis muscle toward the infra-temporal fossa.  In group 2, filler diffusion was observed to create a clefting of the muscle fibers, but did not track through any apparent areolar plane, photographs of which are presented. 

Conclusion: This study provides a greater understanding of the location of HA gel after deep injection within the temporal hollow.  In group 1, volumes in excess of 0.5cc likely do not result in any additional changes in surface topography, as filler migrates inferiorly into the deep temporal space, hidden behind the zygomatic arch.  Our findings indicate that in the previously described “One Up, and One Over” technique, temporal HA filler works primarily by displacement rather than diffusion to effect surface topographical changes. Injections placed at least 0.5 cm more cephalo-posterior effect more localized volume changes.

References:

1. Huang R-L, Xie Y, Wang W, et al. Anatomical Study of Temporal Fat Compartments and its Clinical Application for Temporal Fat Grafting. Aesthetic Surg J. 2017;37(8):855-862. doi:10.1093/asj/sjw257.
2. Sykes JM. Applied Anatomy of the Temporal Region and Forehead for Injectable Fillers. J Drugs Dermatology. 2009;8(10):s24-s27.
3. Swanson CE, Hayman LA, Diaz-Marchan PJ, Watson AB. Imaging the temporal fossa. AJR Am J Roentgenol. 1997;168(3):801-806. doi:10.2214/ajr.168.3.9057538.
4. Swift A. Dr. Arthur Swift's personal "one up, one over" technique to treat signs of aging in the temple hollows. From "Upper Face: Clinical Anatomy and Regional Approaches with Injectable Fillers. . Plast Reconstr Surg. 2015;136(5S):204S-218S. http://wolterskluwer.http.internapcdn.net/wolterskluwer_vitalstream_com/MP4s/permalink/prs/b/prs_136_5_2015_09_03_sykes_prsjd1500629_sdc5.mp4.
5. Fedorov A, Beichel R, Kalpathy-Cramer J, et al. 3D Slicer as an image computing platform for the Quantitative Imaging Network. Magn Resonance Imaging. 2012;30(9):1323-1341. doi:10.1016/j.mri.2012.05.001.