I hope you’re enjoying the meetings and thanks for checking out our poster!
Biomechanical Consequences of Alveolar Cleft Defect
I designed this poster to be bold, so you can easily see our main findings as you wander through the busy poster session.
Now hopefully we can enjoy what we’re all here for: to engage in conversations about our cool science!
So, if you followed our QR link, you’re probably interested in learning more about the details of our study. Find them below.
Our poster will be up on Tuesday, April 5, 2022 in Exhibit hall AB on board C11 from 9am-4pm. I’ll be there from 10:15am-11:15pm. If you’ve stop by and I’m not here, please feel free to contact me or, if you see me around, introduce yourself!
I’m the one with the pink hair (and that’s why I put my picture in the corner).
Expanded Background:
During the 4-10th weeks of development, embryological structures of the facial region merge and fuse to form the palate, separating the oral and nasal cavities. If any of these structures fail to merge, a split (cleft) will remain.
Orofacial clefts are the most common type of congenital craniofacial anomalies (1 in 500 births; Wehby et al, 2010) and can range from a bifid uvula (soft palate) to a complete fissure of the soft palate, bony palate, alveolar process of the maxilla and lip. In severe cases, the oral and nasal cavities remain connected and bony deficiencies can cause alveolar arch collapse, feeding and speech issues. These patients often require multiple coordinated surgical procedures throughout childhood. The goal of the interdisciplinary care team is to improve patient quality of life with the fewest number of operations.
Closure of the oral mucosa is done while the patient is young to facilitate normal feeding and speech and improve cosmetic appearance. Repair of the alveolar defect itself is typically performed before permanent canine eruption (10-12 years) by grafting autologous bone (taken from the patient’s own ilium) into the cleft site. Although this is considered the “gold standard” treatment, complications include pain, discomfort and infection at the donor site. At the graft site, bone maintenance and osteogenesis may also be problematic, with as much as 54% of grafted bone loss one year post-op (van der Meij et al, 2003; Dissaux et al., 2016). In some cases, complete graft failure may occur, requiring additional grafts, which may also fail.
Unfortunately, the reason(s) why these grafts fail is poorly understood.
Previous investigators have suggested that a disruption of intracellular signaling and differential biomechanical forces may be to blame (van der Meij 2003), as pre-surgical cleft size and shape does correlate to graft success (Long et al., 1995; van der Meij 2003). But these biomechanical variables can be difficult to test, and thus, are also not well understood (Chen et al., 2013; Zhao et al., 2008).
Finite element analysis (FEA) is an engineering tool used to examine how objects of complex design respond to loads. Evolutionary biologists have increasingly embraced finite element analysis (FEA) to understand form-function relationships and test mechanical hypotheses in silico when in vivo mechanical experiments are not possible. Virtual modeling experiments can be done to study the effects of specific anatomical features in isolation to tease out links between shape variation, loading and strain regime and biomechanical performance.
Some previous work has used FEA to study alveolar clefts, but models based on clinical cone-beam CT (CBCT) are incomplete because only part of the cranium is imaged. This precludes the incorporation of physiological loading regimes (muscle forces) or boundary conditions (joint restraints) to simulate everyday chewing behaviors (Zhao et al., 2008; Chen et al 2013; Wen & Li, 2013; Harikrishnan & Balakumanon, 2017). Furthermore, although some these studies create artificial gaps to simulate differently shaped clefts, they do not incorporate patient imaging data to assess this shape variation.
By using an integrative approach, we built a composite cranial FEM, that is complete, directly incorporates patient CBCT imaging and allows us to assess variation in cleft geometry and mechanics.
Please be aware that this is pilot work, and is not yet published.
© [Amanda L. Smith] and [amandalsmithphd.com], [2022]. Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited.
(Philadelphia skyline at dusk, photo by Bruce Emmerling, CC Wikimedia)
Amanda L. Smith 