Automated surgical step recognition in transurethral bladder tumor resection using artificial intelligence: transfer learning across surgical modalities

Objective

Automated surgical step recognition (SSR) using AI has been a catalyst in the "digitization" of surgery. However, progress has been limited to laparoscopy, with relatively few SSR tools in endoscopic surgery. This study aimed to create a SSR model for transurethral resection of bladder tumors (TURBT), leveraging a novel application of transfer learning to reduce video dataset requirements.

Materials and methods

Retrospective surgical videos of TURBT were manually annotated with the following steps of surgery: primary endoscopic evaluation, resection of bladder tumor, and surface coagulation. Manually annotated videos were then utilized to train a novel AI computer vision algorithm to perform automated video annotation of TURBT surgical video, utilizing a transfer-learning technique to pre-train on laparoscopic procedures. Accuracy of AI SSR was determined by comparison to human annotations as the reference standard.

Results

A total of 300 full-length TURBT videos (median 23.96 min; IQR 14.13-41.31 min) were manually annotated with sequential steps of surgery. One hundred and seventy-nine videos served as a training dataset for algorithm development, 44 for internal validation, and 77 as a separate test cohort for evaluating algorithm accuracy. Overall accuracy of AI video analysis was 89.6%. Model accuracy was highest for the primary endoscopic evaluation step (98.2%) and lowest for the surface coagulation step (82.7%).

Conclusion

We developed a fully automated computer vision algorithm for high-accuracy annotation of TURBT surgical videos. This represents the first application of transfer-learning from laparoscopy-based computer vision models into surgical endoscopy, demonstrating the promise of this approach in adapting to new procedure types.

Incidence of Venous Thromboembolism and Safety of Perioperative Subcutaneous Heparin During Inflatable Penile Prosthesis Surgery

OBJECTIVE

To identify the incidence of venous thromboembolism (VTE) risk factors, postoperative VTE, and to assess the morbidity of perioperative pharmacologic VTE prophylaxis in men undergoing inflatable penile prosthesis (IPP) surgery.

METHODS

We retrospectively reviewed 215 patients undergoing IPP surgery between July 2017 and June 2019. Univariate and multivariate statistical analyzes were performed to assess pre-operative Caprini risk score and compare post-operative day 0 scrotal drain output, scrotal hematoma formation, and VTE in men who received subcutaneous heparin (SqH) vs those who did not receive SqH.

RESULTS

Of 215 IPP patients, 84% were classified as high or highest risk for VTE utilizing the Caprini risk score. A total of 119 (55%) received perioperative SqH with or without additional anti-thrombotics. Post-operative day 0 scrotal drain output was higher in those who received SqH compared to those who did not receive SqH, 99.9 mL vs 75.6 mL, respectively (P = .001). Minor scrotal hematomas occurred in similar rates in patients who received perioperative SqH vs those who did not, 3.8% vs 6.3%, respectively (P = .38). Similar results were found on subgroup analysis when eliminating patients who received SqH concurrently with other anti-thrombotics. The overall rate of postoperative VTE was 0.9%. No post-operative infections occurred.

CONCLUSION

Patients undergoing IPP surgery are at elevated risk for VTE. To our knowledge, this is the first study showing SqH use in the perioperative IPP surgery setting is safe when used in conjunction with a scrotal drain. Preoperative VTE risk stratification may be performed and can be used to guide clinical decision making regarding pharmacologic prophylaxis.

Pubectomy and urinary reconstruction provides definitive treatment of urosymphyseal fistula following prostate cancer treatment

OBJECTIVE

To describe the natural history, reconstructive solutions, and functional outcomes of those men undergoing pubectomy and urinary reconstruction after prostate cancer treatment.

PATIENTS AND METHODS

This study retrospectively identified 25 patients with a diagnosis of urosymphyseal fistula (UF) following prostate cancer therapy who were treated with urinary reconstruction with pubectomy. This study describes the natural history, reconstructive solutions, and functional outcomes of this cohort.

RESULTS

All 25 patients had a history of pelvic radiotherapy for prostate cancer. The median (interquartile range [IQR]) time from prostate cancer treatment to diagnosis of UF was 11 (6, 16.5) years. The vast majority of men (24/25; 96%) presented with debilitating groin pain during ambulation. Posterior urethral stenosis was common (20/25; 80%), with 60% having repetitive endoscopic treatments. Culture of pubic bone specimens demonstrated active infection in 80%. Discordance between preoperative urine and intraoperative bone cultures was common, 21/22 (95.5%). After surgery, major 90-day complications (Clavien-Dindo Grade III and IV) occurred in eight (32%) patients. Pain was significantly improved, with resolution of pain (24/25; 96%) and restoration of function, the median (IQR) preoperative Eastern Cooperative Oncology Group Performance Status (ECOG PS) was 3 (2, 3) vs median postoperative ECOG PS score of 0 (0, 1).

CONCLUSION

Endoscopic urethral manipulation after radiation for prostate cancer is a risk factor for UF. Conservative management will not provide symptom resolution. Fistula decompression, bone resection, and urinary reconstruction effectively treats chronic infection, improves pain and ECOG PS scores.

Incidence and risk factors for peritoneal carcinomatosis following open radical cystectomy

OBJECTIVE

To characterize the frequency and risk factors of peritoneal carcinomatosis (PC) in patients undergoing open radical cystectomy (RC).

METHODS

We identified 3,285 patients with urothelial carcinoma treated with RC for curative intent between 1980 and 2016. At last follow-up, 72.1% (2,370/3,285) of patients had died, with a median follow-up of 8.6 years (Interquartile Range, (IQR) 3.7, 14.1). PC was defined as any recurrence involving the omentum, small bowel, and mesentery. Overall-specific survival (OSS) and cancer-specific survival (CSS) was evaluated using Kaplan-Meier methodology and log-rank test. Risk factors for mortality and recurrence were performed using Cox proportional hazards regression models.

RESULTS

One hundred and twenty nine (3.9%) patients were diagnosed with PC, while a total of 1,148 (34.9%) patients experienced recurrence at other sites. Median time to PC vs. other-site recurrence was 1.3 (IQR 1.3, 2.3) and 0.9 (IQR 0.5, 2.1) years, respectively (P= 0.04). Only increasing pathologic stage on multivariable analysis was associated with developing PC (pT1 HR 2.51, 95CI 1.14-5.55, P= 0.02; pT2 OR 2.82, 95CI 1.47-5.43, P= 0.002; pT3+ 2.40, 95CI 1.31-4.42, P= 0.005) over other recurrence patterns. Nodal status and tumor margin status were not associated. Patients with PC experienced worse OSS and CSS than other types of recurrence (P< 0.001).

CONCLUSION

PC was identified in almost 4% of patients undergoing open RC. PC is a rare occurrence after RC and primarily impacts patients with locally advanced disease.

Impact of anabolic androgenic steroids on sexual function

Background

To describe the impact of supra-physiologic anabolic-androgenic steroid (AAS) use, including agent, dosage, and duration of therapy, on sexual function.

Methods

We reviewed data from an online survey of AAS users to evaluate their sexual function on and off AAS. The online survey consisted of questions addressing demographics, anabolic steroid use and patterns, ancillary medications, testosterone (T)-related symptoms while on and off of therapy, as well as sexual function which was assessed using the 5-item, International Index of Erectile Function (IIEF-5).

Results

A total of 321 men responded to the survey, of which 90 failed to meet inclusion criteria, for a final cohort of 231 AAS users. The majority of men were Caucasian (85%), employed (62%), and younger than 35 years (58%), while an equal mix were single (47%) or married (46%). The mean IIEF-5 was 22.5, with higher scores associated with increased T dosages (>600 mg/week), use of 17-alpha alkylated hormones and anti-estrogens, and absence of concurrent medical conditions. Lower mean IIEF scores were associated with current and pre-AAS low T symptoms, self-reported angry or violent tendencies, self-reported erectile dysfunction (ED), decreased libido, decreased energy, and depression. After controlling for age, low T symptoms and decreased energy remained significantly associated with lower IIEF scores. Among 127 men reporting de novo decreased libido when not taking AAS, several factors were significantly associated including frequency and duration of T and use of adjunctive therapies, while post-cycle therapies were protective. Men who reported any other de novo symptom (decreased energy, libido, muscle mass or depression) after discontinuing T were also more likely to report de novo ED, as well as those using >10 years or for >40 weeks per year.

Conclusions

The long-term impact of high dose AAS use on sexual function remains poorly defined. Although high T dosages appeared to be protective of erectile function during use, de novo symptoms such as decreased libido and ED occurred more frequently after discontinuing T, particularly among those using more frequently and for longer durations. Given the importance of these findings, long-term studies evaluating the impacts of discontinuing T on sexual dysfunction are indicated.

Medication patterns and fertility rates in a cohort of anabolic steroid users

BACKGROUND

To describe self-reported medication patterns and fertility rates in a population of anabolic steroid (AS) users.

METHODS

We reviewed data from an online survey of AS users and identified a sub-group who had attempted to achieve a pregnancy with their partners while using AS. The online survey consisted of questions addressing demographics, AS use, ancillary medications, and fertility outcomes.

RESULTS

A total of 97 men (of 231 total respondents) had attempted to achieve a pregnancy while taking AS and comprise the current cohort. The majority of men were 25-44 years old (63.9%), married (75.5%) and Caucasian (88.7%). Ancillary drug use was common with only 5.2% denying drug use other than ASs. The most common reported ancillary drugs were antiestrogens (89.7%) and sexual enhancement medications (SEMs) (68%). The fertility rate was 92.8%, with 82.4% achieving pregnancy within one year. Interestingly, only 13.5% sought fertility evaluation with treatment required in 8.3%. Age at initiation of AS use, maximum dosage utilized, yearly duration of supplementation, and number of years using steroids were not associated with a prolonged duration to pregnancy or decreased rate of pregnancy.

CONCLUSIONS

Despite continued use of ASs, this cohort's self-reported fertility rates are unexpectedly high. This is presumably related to cycling of therapy and concomitant use of fertility preserving medications.

Operant responding for sucrose by rats bred for high or low saccharin consumption

The use of rats differing in the intake of sweet substances has highlighted some interesting parallels between taste preferences and drug self-administration. For example, rats selectively bred to consume high (HiS) or low (LoS) amounts of a 0.1% saccharin solution (when compared to water consumption), show corresponding differences across several measures of cocaine self-administration (HiS>LoS). In this study, we measured whether the two strains also differ when response requirements are imposed for obtaining a sucrose reinforcer. Male HiS and LoS rats were measured for operant responding for sucrose pellets under fixed-ratio (FR) schedules of 1, 3, 5 and 10 and under a progressive-ratio (PR) schedule, during which the response requirement for each successive pellet increased exponentially. The effect of systemic naltrexone (0.3, 1 and 3mg/kg) on PR responding for sucrose pellets was also tested. Under all FR and PR schedules, the number of pellets obtained by the LoS rats were significantly lower than those obtained by the HiS rats. Although the LoS weighed more than the HiS rats, this difference does not appear to explain differences in operant behavior. No strain differences in the effect of naltrexone were observed; the 3mg/kg dose reduced the number of pellets obtained in both strains. Measures of locomotor activity taken prior to operant trials suggest that the differences in responding were not due to differences in general activity levels. These studies provide further characterization of the HiS and LoS rat lines by demonstrating that motivation to consume sucrose is greater in HiS than in LoS rats.

Naturally occurring altered peptide ligands control Salmonella-specific CD4+ T cell proliferation, IFN-gamma production, and protective potency

T cell activation required for host defense against infection is an intricately regulated and precisely controlled process. Although in vitro studies indicate that three distinct stimulatory signals are required for T cell activation, the precise contribution of each signal in regulating T cell proliferation and differentiation after in vivo infection is unknown. In this study, altered peptide ligands (APLs) derived from the protective Salmonella-specific FliC Ag and CD4+ T cells specific for the immune-dominant FliC(431-439) peptide within this Ag were used to determine how changes in TCR stimulation impact CD4+ T cell proliferation, differentiation, and protective potency. To explore the prevalence and potential use of altered TCR stimulation by bacterial pathogens, naturally occurring APLs containing single amino acid substitutions in putative TCR contact residues within the FliC(431-439) peptide were identified and used for stimulation under both noninfection and infection conditions. On the basis of this analysis, naturally-occurring APLs that prime proliferation of FliC-specific CD4+ T cells either more potently or less potently compared with the wild-type FliC(431-439) peptide were identified. Remarkably, despite these differences in proliferation, all of the APLs primed reduced IFN-gamma production by FliC(431-439)-specific CD4+ T cells after stimulation in vivo. Moreover, after expression of the parental FliC(431-439) peptide or each APL in recombinant Listeria monocytogenes, only CD4+ T cells stimulated with the wild-type FliC(431-439) peptide conferred significant protection against challenge with virulent Salmonella. These results reveal important and unanticipated roles for TCR stimulation in controlling pathogen-specific CD4+ T cell proliferation, differentiation, and protective potency.