Ashwin Sridhar

Image Based Surgical Instrument Pose Estimation with Multi-class Labelling and Optical Flow

Image based detection, tracking and pose estimation of surgical instruments in minimally invasive surgery has a number of potential applications for computer assisted interventions. Recent developments in the field have resulted in advanced techniques for 2D instrument detection in laparoscopic images, however, full 3D pose estimation remains a challenging and unsolved problem. In this paper, we present a novel method for estimating the 3D pose of robotic instruments, including axial rotation, by fusing information from large homogeneous regions and local optical flow features. We demonstrate the accuracy and robustness of this approach on ex vivo data with calibrated ground truth given by surgical robot kinematics which we will also make available to the community. Qualitative validation on in vivo data from robotic assisted prostatectomy further demonstrates that the technique can function in clinical scenarios.

Robot-assisted intracorporeal pyramid neobladder

To describe a robot‐assisted intracorporeal pyramid neobladder reconstruction technique and report operative and perioperative metrics, postoperative upper tract imaging, neobladder functional outcomes, and oncological outcomes.

Analysis of open and intracorporeal robotic assisted radical cystectomy shows no significant difference in recurrence patterns and oncological outcomes.

OBJECTIVESnTo report and compare early oncological outcomes and cancer recurrence sites among patients undergoing open radical cystectomy (ORC) and robotic-assisted radical cystectomy with intracorporeal urinary diversion (iRARC).nnnMETHODS AND MATERIALSnA total of 184 patients underwent radical cystectomy for bladder cancer. ORC cases (n = 94) were performed between June 2005 and July 2014 while iRARC cases (n = 90) were performed between June 2011 and July 2014. Primary outcome was recurrence free survival (RFS). Secondary outcomes were sites of local and metastatic recurrence, cancer specific survival (CSS) and overall survival (OS).nnnRESULTSnMedian follow-up for patients without recurrence was 33.8 months (interquartile range [IQR]: 20.5-45.4) for ORC; and 16.1 months (IQR: 11.2-27.0) for iRARC. No significant difference in age, sex, precystectomy T stage, precystectomy grade, or lymph node yield between ORC and iRARC was observed. The ORC cohort included more patients with≥pT2 (64.8% ORC vs. 38.9% iRARC) but fewer pT0 status (8.5% ORC vs.vs. 22.2% iRARC) due to lower preoperative chemotherapy use (22.3% ORC vs. 34.4% iRARC). Positive surgical margin rate was significantly higher in the ORC cohort (19.3% vs. 8.2%; P = 0.042). Kaplan-Meir analysis showed no significant difference in RFS (69.5% ORC vs. 78.8% iRARC), cancer specific survival (80.9% ORC vs. 84.4% iRARC), or OS (73.5% ORC vs.vs. iRARC 83.8%) at 24 months. Cox regression analysis showed RFS, cancer specific survival and OS were not influenced by cystectomy technique. No significant difference between local and metastatic RFS between ORC and iRARC was observed.nnnCONCLUSIONnThis study has found no difference in recurrence patterns or oncological outcomes between ORC and iRARC. Recurrent metastatic sites vary, but are not related to surgical technique.

Recovery of Baseline Erectile Function in Men Following Radical Prostatectomy for High-Risk Prostate Cancer: A Prospective Analysis Using Validated Measures

INTRODUCTIONnRecovery of baseline erectile function (EF) after robotic radical prostatectomy in men with high-risk prostate cancer is under-reported. Published studies have selectively reported on low-risk disease using non-validated and poorly defined thresholds for EF recovery.nnnAIMnTo assess return to baseline EF in men after robotic radical prostatectomy for high-risk prostate cancer.nnnMATERIALSnFive hundred thirty-one men underwent robotic radical prostatectomy for high-risk prostate cancer from February 2010 through July 2014. Pre- and postoperative EF was prospectively assessed using the International Index of Erectile Dysfunction (IIEF-5) questionnaire. Multivariate logistic regression analysis determined the effect of age, preoperative function, comorbidities, body mass index, prostate-specific antigen level, cancer stage or grade, nerve-sparing status, adjuvant therapy, and continence on EF return (defined as postoperative return to baseline EF with or without use of phosphodiesterase type 5 inhibitors). Kaplan-Meier analysis and log-rank test were used to analyze return over time. Mann-Whitney U-test was used to compare IIEF-5 scores.nnnMAIN OUTCOME MEASURESnPre- and postoperative EF was assessed using the IIEF-5 Sexual Health Inventory for Men at 3 months, 6 months, 1 year, 2 years, 3 years, and 4 years postoperatively.nnnRESULTSnOverall, return of EF was seen in 23.5% of patients at 18 months. This was significantly increased in men no older than 60 years (Pxa0= .024), with a preoperative IIEF-5 score of at least 22 (Pxa0= .042), and after undergoing neurovascular bundle preservation (34.9% of patients, P < .001). There was no significant change in IIEF-5 scores from 3 to 36 months in patients who were treated with phosphodiesterase type 5 inhibitors in the non-neurovascular bundle preservation group (Pxa0= .87), although there was significant improvement in those receiving second- or third-line therapies (Pxa0= .042). Other than preoperative hypertension (Pxa0= .03), none of the other comorbidities predicted return of EF.nnnCONCLUSIONnIn this study, 23.5% of men recovered to baseline EF. Of those who underwent bilateral neurovascular bundle preservation robotic radical prostatectomy, 70% recovered baseline EF; however, this accounted for only 9.6% of all patients. Only 4% of men who underwent non-neurovascular bundle preservation had baseline recovery with phosphodiesterase type 5 inhibitors up to 36 months. There was significant improvement after use of second- or third-line therapies, indicating the need for earlier institution of these treatment modalities.

Benefits of robotic cystectomy with intracorporeal diversion for patients with low cardiorespiratory fitness: A prospective cohort study

BACKGROUNDnPatients undergoing radical cystectomy have associated comorbidities resulting in reduced cardiorespiratory fitness. Preoperative cardiopulmonary exercise testing (CPET) measures including anaerobic threshold (AT) can predict major adverse events (MAE) and hospital length of stay (LOS) for patients undergoing open and robotic cystectomy with extracorporeal diversion. Our objective was to determine the relationship between CPET measures and outcome in patients undergoing robotic radical cystectomy and intracorporeal diversion (intracorporeal robotic assisted radical cystectomy [iRARC]).nnnMETHODSnA single institution prospective cohort study in patients undergoing iRARC for muscle invasive and high-grade bladder cancer.nnnINCLUSIONnpatients undergoing standardised CPET before iRARC.nnnEXCLUSIONSnpatients not consenting to data collection. Data on CPET measures (AT, ventilatory equivalent for carbon dioxide [VE/VCO2] at AT, peak oxygen uptake [VO2]), and patient demographics prospectively collected. Outcome measurements included hospital LOS; 30-day MAE and 90-day mortality data, which were prospectively recorded. Descriptive and regression analyses were used to assess whether CPET measures were associated with or predicted outcomes.nnnRESULTSnFrom June 2011 to March 2015, 128 patients underwent radical cystectomy (open cystectomy, n = 17; iRARC, n = 111). A total of 82 patients who underwent iRARC and CPET and consented to participation were included. Median (interquartile range): age = 65 (58-73); body mass index = 27 (23-30); AT = 10.0 (9-11), Peak VO2 = 15.0 (13-18.5), VE/VCO2 (AT) = 33.0 (30-38). 30-day MAE = 14/111 (12.6%): death = 2, multiorgan failure = 2, abscess = 2, gastrointestinal = 2, renal = 6; 90-day mortality = 3/111 (2.7%). AT, peak VO2, and VE/VCO2 (at AT) were not significant predictors of 30-day MAE or LOS. The results are limited by the absence of control group undergoing open surgery.nnnCONCLUSIONSnPoor cardiorespiratory fitness does not predict increased hospital LOS or MAEs in patients undergoing iRARC. Overall, MAE and LOS comparable with other series.

In-depth Critical Analysis of Complications Following Robot-assisted Radical Cystectomy with Intracorporeal Urinary Diversion

BACKGROUNDnRobot-assisted radical cystectomy with intracorporeal urinary diversion (iRARC) is an attractive option to open cystectomy, but the benefit in terms of improved outcomes is not established.nnnOBJECTIVEnTo evaluate the early postoperative morbidity and mortality of patients undergoing iRARC and conduct a critical analysis of complications using standardised reporting criteria as stratified according to urinary diversion.nnnDESIGN, SETTING, AND PARTICIPANTSnA total of 134 patients underwent iRARC for bladder cancer at a single centre between June 2011 and July 2015.nnnINTERVENTIONnRadical cystectomy with iRARC.nnnOUTCOME MEASUREMENTS AND STATISTICAL ANALYSISnPatient demographics, pathologic data, and 90-d perioperative mortality and complications were recorded. Complications were reported according to the Clavien-Dindo (CD) classification and stratified according to urinary diversion type and either surgical or medical complications. The chi-square test and t test were used for categorical and continuous variables respectively. Multivariable logistic regression was performed on variables with significance in univariate analysis.nnnRESULTS AND LIMITATIONSnThe 90-d all complication rate following ileal conduit and continent diversion was 68% and 82.4%, and major complications were 21.0% and 20.6% respectively. The 90-d mortality was 3% and 2.9% for ileal conduit and continent diversion patients, respectively. On multivariate analysis, the blood transfusion requirement was independently associated with major complications (p=0.002) and all 30-d (p=0.002) and 90-d (p=0.012) major complications. Male patients were associated with 90-d major complications (p=0.015). Critical analysis identified that surgical complications were responsible for 39.4% of all 90-d major complications. The incidence of surgical complications did not decline with increasing number of iRARC cases performed (p=0.742, r=0.31). Limitations of this study include its retrospective nature, limited sample size, and limited multivariate analysis due to the low number of major complications events.nnnCONCLUSIONSnAlthough complications following iRARC are common, most are low grade. A critical analysis identified surgical complications as a cause of major complications. Addressing this issue could have a significant impact on lowering the morbidity associated with iRARC.nnnPATIENT SUMMARYnWe looked at the surgical outcomes in bladder cancer patients treated with minimally invasive robotic surgery. We found that surgical complications account for most major complications and previous surgical experience may be a confounding factor when interpreting results from a different centre even in a randomised trial setting.

Training in Robotic Surgery—an Overview

Purpose of ReviewThere has been a rapid and widespread adoption of the robotic surgical system with a lag in the development of a comprehensive training and credentialing framework. A literature search on robotic surgical training techniques and benchmarks was conducted to provide an evidence-based road map for the development of a robotic surgical skills for the novice robotic surgeon.Recent FindingsA structured training curriculum is suggested incorporating evidence-based training techniques and benchmarks for progress. This usually involves sequential progression from observation, case assisting, acquisition of basic robotic skills in the dry and wet lab setting along with achievement of individual and team-based non-technical skills, modular console training under supervision, and finally independent practice.SummaryRobotic surgical training must be based on demonstration of proficiency and safety in executing basic robotic skills and procedural tasks prior to independent practice.

Apparatus for Histological Validation of In Vivo and Ex Vivo Magnetic Resonance Imaging of the Human Prostate

This article describes apparatus to aid histological validation of magnetic resonance imaging studies of the human prostate. The apparatus includes a 3D-printed patient-specific mold that facilitates aligned in vivo and ex vivo imaging, in situ tissue fixation, and tissue sectioning with minimal organ deformation. The mold and a dedicated container include MRI-visible landmarks to enable consistent tissue positioning and minimize image registration complexity. The inclusion of high spatial resolution ex vivo imaging aids in registration of in vivo MRI and histopathology data.

Intracorporeal robotic assisted radical cystectomy together with an enhanced recovery programme improves postoperative outcomes by aggregating marginal gains

To assess the cumulative effect of an enhanced recovery after surgery (ERAS) pathway and minimally invasive robot‐assisted radical cystectomy with intracorporeal urinary diversion (iRARC) in comparison with open radical cystectomy (ORC) on length of hospital stay (LOS) and peri‐operative outcomes.

PD43-05 ABSENCE OF EVIDENCE IS NOT EVIDENCE OF ABSENCE: NORMAL AREAS ON MRI COULD HARBOUR SIGNIFICANT TUMOUR

INTRODUCTION AND OBJECTIVES: To evaluate the auxiliary function of periprostatic fat thickness (PPFT) on MRI to Prostate Imaging Reporting and Data System (PI-RADS) in predicting the presence of prostate cancer (PCa) and high grade prostate cancer (HGPCa). METHODS: The demographic data and the clinical information of 683 patients received transrectal ultrasound(TRUS-) guided biopsy and multi-parametric magnetic resonance imaging (mp-MRI) were retrospectively reviewed. In addition, the PPFT was measured as the shortest perpendicular distance from the pubic symphysis to prostate on midsagittal T1-weighted MR images. The univariate and multivariate analyses were performed for determing independent predictors of PCa and HGPCa in whole study cohort and subgroups according to PIRADS score. We also constructed two nomograms for predicting PCa and HGPCa based on binary logistic regression results. RESULTS: Overall, there were 371 patients (54.3%) having PCa and 292 patients (42.8%) having HGPCa. The mean value of PPFT was 4.04mm. Multivariate analysis revealed that age, PSA, TPV, PI-RADS score, PPFT were independent predictors of PCa. All factors plus DRE were independent predictors for HGPCa. The PPFT was the independent predictors of PCa (OR 2.56, p 1⁄4 0.004) and HGPCa (OR 2.70, p 1⁄4 0.014) for subjects with the PI-RADS score of 3. The present two nomograms based on multivariate analysis outperformed the single PI-RADS on aspects of predicting accuracy for PCa (aurea under the curve [AUC]: 0.922 vs 0.883, p1⁄4 0.029) and HGPCa (0.919 vs 0.873, p 1⁄4 0.007). Decision-curve analysis also indicated superior net benefits and wide predicting ranges of the present two nomograms. CONCLUSIONS: The PPFT on mp-MRI is an independent predictor of PCa and HGPCa, especially for patients with the PI-RADS score of 3. The nomograms incorporated predictors of PPFT and PIRADS demonstrate good performance in predicting the prsence of PCa and HGPCa.