helping plastic surgeons improve cleft palate surgery

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Helping plastic surgeons improve cleft palate surgery Josh Inouye, PhD Biomedical Engineering Mechanical and Aerospace Engineering University of Virginia Postdoc Research Day May 2 nd , 2014 mayo.com

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Page 1: Helping plastic surgeons improve cleft palate surgery

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  

Page 2: Helping plastic surgeons improve cleft palate surgery

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

Page 3: Helping plastic surgeons improve cleft palate surgery

INTRODUCTION  

Cleft lip repairs are typically successful at reproducing a normal facial appearance

Before After

Page 4: Helping plastic surgeons improve cleft palate surgery

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.

Page 5: Helping plastic surgeons improve cleft palate surgery

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  

Page 6: Helping plastic surgeons improve cleft palate surgery

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

Page 7: Helping plastic surgeons improve cleft palate surgery

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

Page 8: Helping plastic surgeons improve cleft palate surgery

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  

Page 9: Helping plastic surgeons improve cleft palate 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  

Page 10: Helping plastic surgeons improve cleft palate 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  

Page 11: Helping plastic surgeons improve cleft palate surgery

Our simulation results are supported by clinical results

DISCUSSION  

Nguyen  et  al.  2014,  Plas3c  and  Reconstruc3ve  Surgery  

Least overlap Most overlap

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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  

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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.

Page 14: Helping plastic surgeons improve cleft palate surgery

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