The empty pelvis syndrome: a core data set from the PelvEx collaborative

BACKGROUND

Empty pelvis syndrome (EPS) is a significant source of morbidity following pelvic exenteration (PE), but is undefined. EPS outcome reporting and descriptors of radicality of PE are inconsistent; therefore, the best approaches for prevention are unknown. To facilitate future research into EPS, the aim of this study is to define a measurable core outcome set, core descriptor set and written definition for EPS. Consensus on strategies to mitigate EPS was also explored.

METHOD

Three-stage consensus methodology was used: longlisting with systematic review, healthcare professional event, patient engagement, and Delphi-piloting; shortlisting with two rounds of modified Delphi; and a confirmatory stage using a modified nominal group technique. This included a selection of measurement instruments, and iterative generation of a written EPS definition.

RESULTS

One hundred and three and 119 participants took part in the modified Delphi and consensus meetings, respectively. This encompassed international patient and healthcare professional representation with multidisciplinary input. Seventy statements were longlisted, seven core outcomes (bowel obstruction, enteroperineal fistula, chronic perineal sinus, infected pelvic collection, bowel obstruction, morbidity from reconstruction, re-intervention, and quality of life), and four core descriptors (magnitude of surgery, radiotherapy-induced damage, methods of reconstruction, and changes in volume of pelvic dead space) reached consensus-where applicable, measurement of these outcomes and descriptors was defined. A written definition for EPS was agreed.

CONCLUSIONS

EPS is an area of unmet research and clinical need. This study provides an agreed definition and core data set for EPS to facilitate further research.

Minimum standards of pelvic exenterative practice: PelvEx Collaborative guideline

This document outlines the important aspects of caring for patients who have been diagnosed with advanced pelvic cancer. It is primarily aimed at those who are establishing a service that adequately caters to this patient group. The relevant literature has been summarized and an attempt made to simplify the approach to management of these complex cases.

Postoperative analgesic efficacy of modified continuous transversus abdominis plane block in laparoscopic colorectal surgery: a triple-blind randomized controlled trial

BACKGROUND

The optimal opioid-sparing analgesic regimen following laparoscopic colorectal surgery (LCS) remains uncertain. We sought to determine the efficacy of low-dose bupivacaine infusion via surgeon-inserted modified continuous transversus abdominis plane (mcTAP) catheters after LCS.

METHODS

A parallel-group, placebo-controlled, randomized single-centre trial was conducted between April 2017 and February 2018. Block-of-four randomization and allocation concealment by sequentially-numbered, opaque sealed envelopes were used. Patients, surgeons and assessors were blinded. Fifty-two patients were randomized to receive either 0.2% bupivacaine or saline through mcTAP catheters. A 5 ml bolus followed by a 72 h infusion at 2 ml/h was started, with patient-controlled fentanyl analgesia and oral paracetamol given on demand. Primary outcomes were fentanyl consumptions in the first 24 h, second 24 h, and third 24 h following surgery. Secondary outcomes were pain numeric rating scores, recovery outcomes and complications.

RESULTS

Twenty-five patients in the bupivacaine group and 26 in the control group were analysed. Patients in the bupivacaine group required significantly less fentanyl overall (106.1 vs 484.5 mcg, p < 0.001) and at all time points (first 24 h: 61.0 vs 324.3 mcg, p < 0.001; second 24 h: 36.3 vs 119.0 mcg, p = 0.033; third 24 h: 8.8 vs 41.2, p = 0.030) when compared to placebo. Significantly lower pain scores at rest at 6 h (2.32 vs 4.0, p = 0.002), and 12 h (1.80 vs 3.08, p = 0.011) and on coughing at 6 h (4.56 vs 5.84, p = 0.019), 12 h (3.76 vs 4.96, p = 0.009), and 24 h (3.44 vs 4.24, p = 0.049) as well as significantly lower opioid-related complications such as nausea or vomiting (9 (36%) vs 1 (4%), p = 0.005) were observed in the bupivacaine group. There were no major block-related complications, and recovery outcomes were similar in both groups.

CONCLUSIONS

McTAP block reduces postoperative fentanyl consumption and pain scores after LCS, highlighting its role as a safe and useful opioid-sparing analgesia.

REGISTRATION NUMBER

TCTR20150831001 (Thai Clinical Trials Registry). Full trial protocol can be assessed at https://www.clinicaltrials.in.th/ .

Genetic Interactions Between TRPC6 and NPHS1 Variants Affect Posttransplant Risk of Recurrent Focal Segmental Glomerulosclerosis

Individuals with TRPC6 mutations have variable phenotypes, ranging from healthy carrier to focal segmental glomerulosclerosis (FSGS) leading to renal failure. Here, we describe a family where six members had a novel TRPC6 p.R68W (c.202C>T) mutation, two of whom had renal failure from FSGS, and one had proteinuria. One healthy carrier donated a kidney to her sister. Both donor and recipient had no proteinuria at 20 years posttransplant. Two synonymous NPHS1 polymorphisms, rs2285450 (c.294C>T) and rs437168 (c.2289C>T) segregated with renal failure in this family. These variants had higher allele frequencies in 97 unrelated patients with nephrotic syndrome or FSGS compared to 224 controls. Using patch-clamp experiments in HEK293 and podocytes, we showed that the p.R68W mutation increased TRPC6 current amplitudes, which may be explained by enhanced TRPC6 surface expression. Additionally, while wild-type nephrin suppressed TRPC6 currents, this ability was lost in the presence of NPHS1 c.294C>T polymorphism. When cells were transfected according to combined TRPC6 and NPHS1 genotypes in the family, those representing the donor had lower TRPC6 currents than cells representing the recipient, suggesting that interactions between TRPC6 and NPHS1 variants could possibly account for the variable penetrance of TRPC6 mutations and the absence of recurrence in the graft.

Loss of vasopressin-immunoreactive neurons in alcoholics is dose-related and time-dependent

The chronic consumption of alcohol significantly reduces the number of vasopressin-producing neurons in the rat supraoptic nucleus [Maderia et al. (1993) Neourscience 56, 657-672] suggesting this region is particularly vulnerable to alcohol neurotoxicity. As hypothalamic vasopressin producing neurons are necessary for fluid homeostasis, it is important to assess if similar changes occur in humans. We analysed arginine vasopressin-immunoreactive neurons in the magnocellular hypothalamic nuclei of ten chronic alcoholic men (consuming > 80 g of ethanol per day) and four age- and sex-matched controls (consuming < 10g of ethanol per day). Brains were collected at autopsy and fixed in formalin. Serial 50 mu m-thick-sections of the hypothalamus were stained and assessed. The volume of the paraventricular and supraoptic nuclei and number of neurons were estimated using Cavalieri's principle and the optical dissector technique. The volume of these nuclei significantly correlated with the number of neurons and the number of vasopressin-immunoreactive neurons, and these measures significantly correlated with the maximum daily intake of alcohol. There was a loss of neurons at consumption levels greater than 100 g of ethanol per day, principally affecting the supraoptic nucleus although neuron loss also occurred in the paraventricular nucleus in cases with long histories of alcohol consumption. These results indicate that chronic alcohol consumption is toxic to hypothalamic vasopressin-producing neurons in a concentration- and time-dependent manner. As these magnocellular neurons are osmo-receptive, neuronal loss may result in fluid imbalances.

Comparison of the number of vasopressin-producing hypothalamic neurons in rats and humans

The aim of this study was to assess the number and proportion of vasopressin-producing neurons in the hypothalamic magnocellular nuclei in rats and humans. Accurate and unbiased neuronal counts were estimated using the optical disector method. Arginine vasopressin-containing neurons were immunohistochemically visualized in formalin-fixed tissue sections. The magnocellular neurons were similar in size and morphology in both species. While the human hypothalamus contained significantly more vasopressin-containing neurons compared with the rat (36-fold increase), the proportion of vasopressin-containing neurons between species was similar. In both species, the majority of supraoptic neurons contained vasopressin, however the proportion of vasopressin-containing neurons in the human paraventricular nucleus was double that of the rat (nearly a 100-fold increase in number). These results suggest that the paraventricular nucleus contributes significantly to the release of vasopressin from the posterior pituitary in humans, whereas in rats vasopressin is mainly released by supraoptic neurons.

Influence of digits, ectoderm, and retinoic acid on chondrogenesis by mouse interdigital mesoderm in culture

We have cultured tissues isolated from the interdigital zones (IDZ) of the mouse footplate in the presence of the digits, ectoderm, and all-trans retinoic acid. The objective was to understand how these various factors influence the developmental fate of the interdigital tissues. Neutral red staining showed that these tissues normally differentiate by dying between day 12.5-14.5. However, if they were isolated from the footplate between day 12.5-13.5 (when cell death is not overtly obvious in the IDZ) and maintained in organ culture, these tissues would develop into cartilage and soft connective tissues. In culture, chondrogenesis is initiated very rapidly in the interdigital explants as revealed by in situ hybridization with riboprobes specific for type IIA and IIB procollagen mRNAs. The ability of interdigital tissues to form cartilage is not attributed to factors present in the serum of the culture medium as this phenomenon is also observed in serumless cultures. We have found that if all-trans retinoic acid, at concentrations of 10-50 ng/ml culture medium, were added to the explants it could inhibit chondrogenesis and promote cell death. Moreover, in some of the cultures, a single digit was left attached to the interdigital tissue. This also dramatically reduced the incidence of chondrogenesis. We have tried to determine whether the digits and ectoderm can produce a diffusible factor that can prevent cartilage from developing by culturing day 12.5 interdigital tissues in ectoderm and digit conditioned media. The ectoderm conditioned medium had no effects on interdigital growth or chondrogenesis. In contrast, the size of interdigital explants cultured in the presence of digit conditioned medium was shown to be significantly smaller than the control. These explants also produced a smaller quantity of cartilage as revealed by Alcian blue binding assay. In sum, our results showed that the fate of the interdigital tissues are not fully determined until after day 13.5. These tissues have the potentials to form cartilage and soft connective tissues. We tentatively propose that these interdigital tissues do not normally realize their histogenetic potentials because of the antichondrogenic influence of the digits and retinoic acid.