Daniel W. Good

Elasticity as a biomarker for prostate cancer: a systematic review

To systematically review the range of methods available for assessing elasticity in the prostate and to examine its use as a biomarker for prostate cancer.

Quantitative diagnostics of soft tissue through viscoelastic characterization using time-based instrumented palpation.

Although palpation has been successfully employed for centuries to assess soft tissue quality, it is a subjective test, and is therefore qualitative and depends on the experience of the practitioner. To reproduce what the medical practitioner feels needs more than a simple quasi-static stiffness measurement. This paper assesses the capacity of dynamic mechanical palpation to measure the changes in viscoelastic properties that soft tissue can exhibit under certain pathological conditions. A diagnostic framework is proposed to measure elastic and viscous behaviors simultaneously using a reduced set of viscoelastic parameters, giving a reliable index for quantitative assessment of tissue quality. The approach is illustrated on prostate models reconstructed from prostate MRI scans. The examples show that the change in viscoelastic time constant between healthy and cancerous tissue is a key index for quantitative diagnostics using point probing. The method is not limited to any particular tissue or material and is therefore useful for tissue where defining a unique time constant is not trivial. The proposed framework of quantitative assessment could become a useful tool in clinical diagnostics for soft tissue.

Elasticity as a biomarker for prostate cancer

To systematically review the range of methods available for assessing elasticity in the prostate and to examine its use as a biomarker for prostate cancer.

Contemporary practice and technique-related outcomes for radical prostatectomy in the UK: a report of national outcomes.

To determine current radical prostatectomy (RP) practice in the UK and compare surgical outcomes between techniques.

Five‐year oncological outcomes of endoscopic extraperitoneal radical prostatectomy (EERPE) for prostate cancer: results from a medium‐volume UK centre

To determine the 5‐year oncological outcomes of endoscopic extraperitoneal radical prostatectomy (EERPE) from a medium‐volume centre, thereby providing much needed data on outcomes from the UK.

A Critical Analysis of the Learning Curve and Postlearning Curve Outcomes of Two Experience- and Volume-Matched Surgeons for Laparoscopic and Robot-Assisted Radical Prostatectomy

BACKGROUND AND PURPOSE There remains equipoise with regard to whether laparoscopic radical prostatectomy (LRP) or robot-assisted radical prostatectomy (RARP) has any benefit over the other. Despite this, there is a trend for the increasing adoption of RARP at great cost to health services across the world. The aim was to critically analyze the learning curve and outcomes for LRP and RARP for two experience- and volume-matched surgeons who have completed the learning curve for LRP and RARP. PATIENTS AND METHODS Two experience- and volume-matched LRP and RARP surgeons who have completed the learning curve were compared with respect to their learning curve and outcomes for RARP and LRP. There were 531 RARP and 550 LRPs analyzed from April 2003 until January 2012 at two relatively high-volume United Kingdom centers. Outcome measures included operative time, blood loss, complication rate (Clavien-Dindo grade III), positive surgical margin (PSM) rate, and early continence rate. RESULTS Learning curves for blood loss, operative times, and complication rate were similar between groups. The overall PSM rate and pT2 PSM rate learning curves were longer for RARP compared with LRP but shorter for early continence. Apical PSM showed no learning curve for RARP; however, a long learning curve for LRP and the rate was lower for RARP than for LRP (P=<0.001). CONCLUSIONS This study of RARP and LRP identified that both modalities had long learning curves. Despite the long learning curve for RARP, significant benefits in lower PSM rates and better early continence in comparison with LRP exist. There are benefits to patients with RARP over LRP, especially those linked to better apical dissection (apical PSM and early continence).

Five-year oncological outcomes of endoscopic extraperitoneal radical prostatectomy (EERPE) for prostate cancer

To determine the 5‐year oncological outcomes of endoscopic extraperitoneal radical prostatectomy (EERPE) from a medium‐volume centre, thereby providing much needed data on outcomes from the UK.

Tissue Quality Assessment Using a Novel Direct Elasticity Assessment Device (The E-Finger): A Cadaveric Study of Prostatectomy Dissection

Introduction 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. Material and 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.

Small bowel injury after suprapubic catheter insertion presenting 3 years after initial insertion

A 77-year-old woman was referred to urology with blockages of her suprapubic catheter (SPC). The catheter was replaced easily in the emergency department, however, no urine was draining, only a cloudy green fluid was visible. On cystoscopy bilious material was identified in the bladder. There was no catheter visible. There seemed to be a fistulous tract entering the bladder at the left dome. The urethra was dilated, a urethral catheter was placed and the SPC was removed. A CT demonstrated that the SPC tract transfixed a loop of pelvic small bowel and entered the bladder with no intraperitoneal contrast leak. The patient recovered well and did not require laparotomy. This case emphasises that bowel perforation, although rare, must be considered as a complication of SPC placement even years after initial insertion when catheter problems arise. Unusually, we learn that this complication may not present with abdominal pain or peritonism.

Histology-based homogenization analysis of soft tissue: application to prostate cancer

It is well known that the changes in tissue microstructure associated with certain pathophysiological conditions can influence its mechanical properties. Quantitatively relating the tissue microstructure to the macroscopic mechanical properties could lead to significant improvements in clinical diagnosis, especially when the mechanical properties of the tissue are used as diagnostic indices such as in digital rectal examination and elastography. In this study, a novel method of imposing periodic boundary conditions in non-periodic finite-element meshes is presented. This method is used to develop quantitative relationships between tissue microstructure and its apparent mechanical properties for benign and malignant tissue at various length scales. Finally, the inter-patient variation in the tissue properties is also investigated. Results show significant changes in the statistical distribution of the mechanical properties at different length scales. More importantly the loss of the normal differentiation of glandular structure of cancerous tissue has been demonstrated to lead to changes in mechanical properties and anisotropy. The proposed methodology is not limited to a particular tissue or material and the example used could help better understand how changes in the tissue microstructure caused by pathological conditions influence the mechanical properties, ultimately leading to more sensitive and accurate diagnostic technologies.