helping plastic surgeons improve cleft palate surgery
TRANSCRIPT
Helping plastic surgeons improve cleft palate surgery
Josh Inouye, PhD Biomedical Engineering Mechanical and Aerospace Engineering University of Virginia Postdoc Research Day May 2nd, 2014
mayo.com
Cleft lip
Cleft palate
mayo.com
INTRODUCTION
Together, cleft lips and palates are the most common birth defects in the US, requiring repair by plastic surgeons
INTRODUCTION
Cleft lip repairs are typically successful at reproducing a normal facial appearance
Before After
INTRODUCTION
However, 25% of cleft palate surgeries fail to enable normal speech, resulting in speech impediments
The palate might be closed, yet 25% of children do not develop normal speech, leading to progressive re-repair surgeries and negative psychological effects from teasing by peers.
Perceived by peers as:
Speech impediment effects
More vulnerable to: - Less intelligent - Less confident - Less pleasant - Less honest - Less attractive Lallh & Rochet, 2014
- Bullying - Teasing - Learning disabilities
INTRODUCTION
Of principal importance in establishing normal speech is uniting the clefted halves of the main palate muscle at the midline of the palate
INTRODUCTION
Clefted muscle halves unrepaired
Muscle halves united at midline
Unrepaired cleft palate Repaired cleft palate
INTRODUCTION
The existence and extent of muscle overlap at the midline varies widely among surgeons and the various surgical techniques
- However, no studies have been published examining the mechanism and effects of various amounts of overlap!
No muscle overlap present
Muscle overlap present, but amount varies
Overlap
METHODS
We created a computer simulation to reflect actual palate anatomy and systematically evaluate the effects of changing muscle overlap
Palate muscle
Computer simulation
Soft palate
Anterior di-rection
Palate anatomy
Inouye et al. 2015, Journal of Craniofacial Surgery
METHODS
We calculated closure force produced by the palate muscle when contracted to estimate the risk of impaired speech, with higher forces being more beneficial
Closure force calculated
F
Muscle at rest
Midline plane (cutaway view)
Muscle contracted
Inouye et al. 2015, Journal of Craniofacial Surgery
RESULTS
Our simulations show that closure force varies widely with varying overlap percentages, suggesting that overlap is a crucial element to surgical success
Separation No overlap Optimal overlap
Too much overlap
Closure force (N) Higher forces suggest
greater probability of
surgical success
−20 −10 0 10 20 300
0.2
0.4
% overlap
Inouye et al. 2015, Journal of Craniofacial Surgery
Our simulation results are supported by clinical results
DISCUSSION
Nguyen et al. 2014, Plas3c and Reconstruc3ve Surgery
Least overlap Most overlap
Our collaborating surgeon has modified his procedure because of our modeling work
DISCUSSION
“The work has absolutely influenced how I do surgery for wide cle@ palates. Before this work, I used to suture the muscle end to end during my repair. Since this work has defined the op3mal physics of the muscle, I now try to overlap the muscles by at least 20%.”
-‐Kant Lin, MD President, American Society of Maxillofacial Surgeons Chief, Division of Craniofacial Surgery Department of PlasNc Surgery University of Virginia
CONCLUSION
Contrary to popular opinion of many plastic surgeons, muscle overlap (as shown by our simulations) has a huge effect on the function of the soft palate following surgery and may be one of the most powerful surgical tools for eliminating failures of cleft palate repairs.
Acknowledgements
Co-authors: • Kant Lin, MD • Katie Pelland • Kathleen Borowitz, CCC-SLP • Silvia Blemker, PhD
Lab members: • Geoffrey Handsfield, PhD • Xiao Hu, PhD • Kelly Virgilio • Katie Knaus • Shawn Russell, PhD • Nic Fiorentino, PhD