Robotic-assisted radical prostatectomy-impact of a mentorship program on oncological outcomes during the learning curve.

BACKGROUND AND AIMS: The learning curve for robotic-assisted radical prostatectomy (RARP) is estimated to be about 50-200 cases. This study will evaluate the benefit of a mentorship programme after completing a mini-fellowship in RARP by an experienced surgeon who previously trained in open and laparoscopic surgery. METHODS: Our study was a retrospective comparative analysis of RARP performed by a single consultant urologist. A retrospective chart review of the first 120 cases was performed. The 120 patients were divided into three groups of 40 cases. For the first 40 cases, an appropriately qualified mentor was present. The peri-operative and oncological outcomes were compared between the three groups. RESULTS: Operative times significantly decreased with experience (250 min vs 234 min vs 225 min, p < 0.05). Complication rates, estimated blood loss, and length of stay were similar between all groups. There was a higher rate of positive margins in the final group (20% vs 17.5% vs 32.5%, p < 0.5). There was a greater number of pT3 tumours in group 3 (42%, n = 17) compared to groups 1 and 2 (20%, n = 8, and 22.5%, n = 9) which may account for the higher rate of positive margins in this group. CONCLUSION: In the transition of an experienced laparoscopic surgeon to robotic surgery, we showed that there is a benefit of a mentorship programme after a mini-fellowship in reducing the impact of the learning curve on patient outcomes. Ongoing mentorship may be of benefit in cases where a high volume of tumour is suspected and should be avoided in the early part of the learning curve to maximise oncological outcomes.

Spermatic vein embolization as a treatment for symptomatic varicocele.

INTRODUCTION: Varicocele is a relatively common condition in men that causes pain in approximately 10% of cases. There have been few studies to date assessing the improvements in both pain and quality of life parameters associated with spermatic vein embolization (SVE) as a treatment for patients with symptomatic varicocele, so we aimed to assess this. METHODS: A review was carried out of consecutive SVE procedures performed at our institution from 2013-2019. Only patients with painful varicocele were included after other causes of testicular pain were excluded. The technique employed was a combination of distal coil embolization of the spermatic vein with 4-6 mm coils at the level of the inguinal canal, as well as sclerotherapy to prevent reflux of sclerosant. Furthermore, a prospective validated Pain Impact Questionnaire-6 (PIQ-6) was performed to assess for improvement in quality of life. A matched pair Student two-tailed t-test was used to compare mean scores pre- and post-treatment, with 95% confidence intervals presented as T scores and their associated p-values. RESULTS: Over six years, 62 SVE procedures were performed for symptomatic varicocele. Success rate was 95%, with a median followup of nine months. Two patients had a failed procedure on two occasions requiring subsequent surgical ligation. There was one clinically significant recurrence. All components of PIQ-6 score showed a statistically significant reduction post-SVE, most noticeably pain severity and impact on leisure activities. CONCLUSIONS: SVE is a safe, effective, and well-tolerated treatment for symptomatic varicocele, improving pain and quality of life.

The identification and neurochemical characterization of central neurons that target parasympathetic preganglionic neurons involved in the regulation of choroidal blood flow in the rat eye using pseudorabies virus, immunolabeling and conventional pathway tracing methods.

The choroidal blood vessels of the eye provide the main vascular support to the outer retina. These blood vessels are under parasympathetic vasodilatory control via input from the pterygopalatine ganglion (PPG), which in turn receives its preganglionic input from the superior salivatory nucleus (SSN) of the hindbrain. The present study characterized the central neurons projecting to the SSN neurons innervating choroidal PPG neurons, using pathway tracing and immunolabeling. In the initial set of studies, minute injections of the Bartha strain of the retrograde transneuronal tracer pseudorabies virus (PRV) were made into choroid in rats in which the superior cervical ganglia had been excised (to prevent labeling of sympathetic circuitry). Diverse neuronal populations beyond the choroidal part of ipsilateral SSN showed transneuronal labeling, which notably included the parvocellular part of the paraventricular nucleus of the hypothalamus (PVN), the periaqueductal gray, the raphe magnus (RaM), the B3 region of the pons, A5, the nucleus of the solitary tract (NTS), the rostral ventrolateral medulla (RVLM), and the intermediate reticular nucleus of the medulla. The PRV+ neurons were located in the parts of these cell groups that are responsive to systemic blood pressure signals and involved in systemic blood pressure regulation by the sympathetic nervous system. In a second set of studies using PRV labeling, conventional pathway tracing, and immunolabeling, we found that PVN neurons projecting to SSN tended to be oxytocinergic and glutamatergic, RaM neurons projecting to SSN were serotonergic, and NTS neurons projecting to SSN were glutamatergic. Our results suggest that blood pressure and volume signals that drive sympathetic constriction of the systemic vasculature may also drive parasympathetic vasodilation of the choroidal vasculature, and may thereby contribute to choroidal baroregulation during low blood pressure.

Regional gastric contractility alterations in a diabetic gastroparesis mouse model: effects of cholinergic and serotoninergic stimulation.

The C57BLKS/J db/db mouse develops hyperglycemia and has delayed gastric emptying that is improved with tegaserod, a partial 5-HT4 agonist. Our aims here were to determine regional gastric contractility alterations in C57BLKS/J db/db mice and to determine the effects of serotonin and tegaserod. The contractile effects of bethanechol, serotonin, and tegaserod in fundic, antral, and pyloric circular muscle were compared in C57BLKS/J db/db mice and normal littermates. The effects of tetrodotoxin, atropine, and 5-HT receptor antagonists were studied. Contractions in response to bethanechol were decreased in the fundus, similar in the antrum, but increased in the pylorus in diabetic mice compared with controls. Serotonin and, to a lesser extent, tegaserod caused contractions that were more pronounced in the fundus than in the antrum and pylorus in both diabetic and normal mice. Serotonin-induced contractions were partially inhibited by atropine, the 5-HT4 antagonist GR113808, and the 5-HT2 antagonist cinanseron but not tetrodotoxin. Regional gastric contractility alterations are present in this diabetic gastroparesis mouse model. Fundic contractility was decreased, but pyloric contractility was increased in the pylorus to cholinergic stimulation in diabetic mice. Serotonin's contractile effect is mediated, in part, through muscarinic, 5-HT2, and 5-HT4 receptors. This study suggests that fundic hypomotility and pyloric hypercontractility, rather than antral hypomotility, play important roles for the gastric dysmotility that occurs in diabetes.

Inhibitory effects of botulinum toxin on pyloric and antral smooth muscle.

Botulinum toxin injection into the pylorus is reported to improve gastric emptying in gastroparesis. Classically, botulinum toxin inhibits ACh release from cholinergic nerves in skeletal muscle. The aim of this study was to determine the effects of botulinum toxin on pyloric smooth muscle. Guinea pig pyloric muscle strips were studied in vitro. Botulinum toxin type A was added; electric field stimulation (EFS) was performed every 30 min for 6 h. ACh (100 microM)-induced contractile responses were determined before and after 6 h. Botulinum toxin caused a concentration-dependent decrease of pyloric contractions to EFS. At a low concentration (2 U/ml), botulinum toxin decreased pyloric contractions to EFS by 43 +/- 9% without affecting ACh-induced contractions. At higher concentrations (10 U/ml), botulinum toxin decreased pyloric contraction to EFS by 75 +/- 7% and decreased ACh-induced contraction by 79 +/- 9%. In conclusion, botulinum toxin inhibits pyloric smooth muscle contractility. At a low concentration, botulinum toxin decreases EFS-induced contractile responses without affecting ACh-induced contractions suggesting inhibition of ACh release from cholinergic nerves. At higher concentrations, botulinum toxin directly inhibits smooth muscle contractility as evidenced by the decreased contractile response to ACh.