Tissue quality assessment using a novel direct elasticity assessment device (the E-finger): a cadaveric study of prostatectomy dissection.
BACKGROUND
Minimally invasive radical prostatectomy (RP) (robotic and laparoscopic), have brought improvements in the outcomes of RP due to improved views and increased degrees of freedom of surgical devices. Robotic and laparoscopic surgeries do not incorporate haptic feedback, which may result in complications secondary to inadequate tissue dissection (causing positive surgical margins, rhabdosphincter damage, etc). We developed a micro-engineered device (6 mm2 sized) [E-finger]) capable of quantitative elasticity assessment, with amplitude ratio, mean ratio and phase lag representing this. The aim was to assess the utility of the device in differentiating peri-prostatic tissue types in order to guide prostate dissection.


METHODS
Two embalmed and 2 fresh frozen cadavers were used in the study. Baseline elasticity values were assessed in bladder, prostate and rhabdosphincter of pre-dissected embalmed cadavers using the micro-engineered device. A measurement grid was created to span from the bladder, across the prostate and onto the rhabdosphincter of fresh frozen cadavers to enable a systematic quantitative elasticity assessment of the entire area by 2 independent assessors. Tissue was sectioned along each row of elasticity measurement points, and stained with haematoxylin and eosin (H&E). Image analysis was performed with Image Pro Premier to determine the histology at each measurement point.


RESULTS
Statistically significant differences in elasticity were identified between bladder, prostate and sphincter in both embalmed and fresh frozen cadavers (p = < 0.001). Intra-class correlation (ICC) reliability tests showed good reliability (average ICC = 0.851). Sensitivity and specificity for tissue identification was 77% and 70% respectively to a resolution of 6 mm2.


CONCLUSIONS
This cadaveric study has evaluated the ability of our elasticity assessment device to differentiate bladder, prostate and rhabdosphincter to a resolution of 6 mm2. The results provide useful data for which to continue to examine the use of elasticity assessment devices for tissue quality assessment with the aim of giving haptic feedback to surgeons performing complex surgery.
Edinburgh Urological Cancer Group, University of Edinburgh, Western General Hospital, Edinburgh, EH2 4XU, United Kingdom; Department of Urology, Western General Hospital, NHS Lothian, Edinburgh, United Kingdom.
Daniel W
DW
Good
Department of Anatomy, University of Edinburgh, Edinburgh, United Kingdom.
Ashfaq
A
Khan
School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, United Kingdom.
Steven
S
Hammer
School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, United Kingdom.
Paul
P
Scanlan
School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, United Kingdom.
Wenmiao
W
Shu
Edinburgh Urological Cancer Group, University of Edinburgh, Western General Hospital, Edinburgh, EH2 4XU, United Kingdom; Department of Urology, Western General Hospital, NHS Lothian, Edinburgh, United Kingdom.
Simon
S
Phipps
Department of Anatomy, University of Edinburgh, Edinburgh, United Kingdom.
Simon H
SH
Parson
Edinburgh Urological Cancer Group, University of Edinburgh, Western General Hospital, Edinburgh, EH2 4XU, United Kingdom; Department of Urology, Western General Hospital, NHS Lothian, Edinburgh, United Kingdom.
Grant D
GD
Stewart
School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, United Kingdom.
Robert
R
Reuben
Edinburgh Urological Cancer Group, University of Edinburgh, Western General Hospital, Edinburgh, EH2 4XU, United Kingdom; Department of Urology, Western General Hospital, NHS Lothian, Edinburgh, United Kingdom.
S Alan
SA
McNeill
D002102:Cadaver; D004210:Dissection / Q000295:instrumentation; D004548:Elasticity; D006801:Humans; D008297:Male; D011467:Prostate / Q000502:physiology; D011468:Prostatectomy / Q000295:instrumentation*; D012371:Robotics / Q000295:instrumentation*; D001743:Urinary Bladder / Q000502:physiology