NKX3.1 Localization to Mitochondria Suppresses Prostate Cancer Initiation

Mitochondria provide the first line of defense against the tumor-promoting effects of oxidative stress. Here we show that the prostate-specific homeoprotein NKX3.1 suppresses prostate cancer initiation by protecting mitochondria from oxidative stress. Integrating analyses of genetically engineered mouse models, human prostate cancer cells, and human prostate cancer organotypic cultures, we find that, in response to oxidative stress, NKX3.1 is imported to mitochondria via the chaperone protein HSPA9, where it regulates transcription of mitochondrial-encoded electron transport chain (ETC) genes, thereby restoring oxidative phosphorylation and preventing cancer initiation. Germline polymorphisms of NKX3.1 associated with increased cancer risk fail to protect from oxidative stress or suppress tumorigenicity. Low expression levels of NKX3.1 combined with low expression of mitochondrial ETC genes are associated with adverse clinical outcome, whereas high levels of mitochondrial NKX3.1 protein are associated with favorable outcome. This work reveals an extranuclear role for NKX3.1 in suppression of prostate cancer by protecting mitochondrial function. SIGNIFICANCE: Our findings uncover a nonnuclear function for NKX3.1 that is a key mechanism for suppression of prostate cancer. Analyses of the expression levels and subcellular localization of NKX3.1 in patients at risk of cancer progression may improve risk assessment in a precision prevention paradigm, particularly for men undergoing active surveillance.See related commentary by Finch and Baena, p. 2132.This article is highlighted in the In This Issue feature, p. 2113.

Could FiLaC™ be effective in the treatment of anal fistulas? A systematic review of observational studies and proportional meta-analysis

AIM

Fistula Laser Closure (FiLaC™) is a novel sphincter-preserving technique that is based on new technologies and shows promising results in repairing anal fistulas whilst maintaining external sphincter function. The aim of the present meta-analysis is to present the efficacy and the safety of FiLaC™ in the management of anal fistula disease.

METHOD

The present proportional meta-analysis was designed using the PRISMA and AMSTAR guidelines. We searched MEDLINE, Scopus, clinicaltrials.gov, Embase, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar databases from inception until November 2019.

RESULTS

Overall, eight studies were included that recruited 476 patients. The pooled success rate of the technique was 63% (95% CI 50%-75%). The pooled complication rate was 8% (95% CI 1%-18%). Sixty-six per cent of patients had a transsphincteric fistula and 60% had undergone a previous surgical intervention, mainly the insertion of a seton (54%). The majority had a cryptoglandular fistula. Operation time and follow-up period were described for each study.

CONCLUSION

FiLaC™ seems to be an efficient therapeutic option for perianal fistula disease with an adequate level of safety that preserves quality of life. Nevertheless, randomized trials need to be designed to compare FiLaC™ with other procedures for the management of anal fistulas such as ligation of intersphincteric fistula tract, anal advancement flaps, fibrin glue, collagen paste, autologous adipose tissue, fistula plug and video-assisted anal fistula treatment.

Intrinsic predictors of prolonged length of stay in a colorectal enhanced recovery pathway: a prospective cohort study and multivariate analysis

AIM

This was a prospective cohort study to determine the intrinsic non-modifiable factors influencing length of stay (LOS) in unselected consecutive patients undergoing elective colorectal surgery within an enhanced recovery pathway.

METHODS

This study interrogated a prospective database of consecutive elective procedures from October 2006 to April 2011 at a tertiary referral academic hospital in the UK to identify independent predictors of prolonged length of stay (pLOS). pLOS was defined as longer than median length of stay (mLOS). Differences in determinants were identified in three groups of increasing operative complexity.

RESULTS

In all, 872 procedures were identified and ranged from a simple ileostomy reversal to complex total pelvic exenteration. Preoperative anaemia and American Society of Anesthesiologists (ASA) Grade III+ predicted pLOS in stoma reversal surgery patients (n = 191, mLOS 4 days). In colonic and small bowel surgery (n = 444, mLOS 8 days), an open procedure, new stoma formation, planned critical care admission and ASA III+ predicted pLOS. New stoma formation and planned critical care admission predicted pLOS in patients undergoing pelvic rectal surgery (n = 237, mLOS 11 days). pLOS was associated with significantly higher morbidity across Dindo-Clavien grades and a longer time to postoperative functional recovery and discharge.

CONCLUSIONS

Operative complexity is associated with longer LOS even with an established enhanced recovery pathway in place. Intrinsic non-modifiable predictors of pLOS differ with operative complexity, and this should be taken into account when planning benchmarking and research across units.

The Association of Coloproctology of Great Britain and Ireland consensus guidelines in surgery for inflammatory bowel disease

AIM

There is a requirement of an expansive and up to date review of surgical management of inflammatory bowel disease (IBD) that can dovetail with the medical guidelines produced by the British Society of Gastroenterology.

METHODS

Surgeons who are members of the ACPGBI with a recognised interest in IBD were invited to contribute various sections of the guidelines. They were directed to produce a procedure based document using literature searches that were systematic, comprehensible, transparent and reproducible. Levels of evidence were graded. An editorial board was convened to ensure consistency of style, presentation and quality. Each author was asked to provide a set of recommendations which were evidence based and unambiguous. These recommendations were submitted to the whole guideline group and scored. They were then refined and submitted to a second vote. Only those that achieved >80% consensus at level 5 (strongly agree) or level 4 (agree) after 2 votes were included in the guidelines.

RESULTS

All aspects of surgical care for IBD have been included along with 157 recommendations for management.

CONCLUSION

These guidelines provide an up to date and evidence based summary of the current surgical knowledge in the management of IBD and will serve as a useful practical text for clinicians performing this type of surgery.

Tumor Evolution and Drug Response in Patient-Derived Organoid Models of Bladder Cancer

Bladder cancer is the fifth most prevalent cancer in the U.S., yet is understudied, and few laboratory models exist that reflect the biology of the human disease. Here, we describe a biobank of patient-derived organoid lines that recapitulates the histopathological and molecular diversity of human bladder cancer. Organoid lines can be established efficiently from patient biopsies acquired before and after disease recurrence and are interconvertible with orthotopic xenografts. Notably, organoid lines often retain parental tumor heterogeneity and exhibit a spectrum of genomic changes that are consistent with tumor evolution in culture. Analyses of drug response using bladder tumor organoids show partial correlations with mutational profiles, as well as changes associated with treatment resistance, and specific responses can be validated using xenografts in vivo. Our studies indicate that patient-derived bladder tumor organoids represent a faithful model system for studying tumor evolution and treatment response in the context of precision cancer medicine.

Surgery for constipation: systematic review and clinical guidance: Paper 1: Introduction & Methods

AIM

This manuscript provides the introduction and detailed methodology used in subsequent reviews to assess the outcomes of surgical interventions with the primary intent of treating chronic constipation in adults and to develop recommendations for practice.

METHOD

PRISMA guidance was adhered to throughout. A literature search was performed in public databases between January 1960 and February 2016. Studies that fulfilled strictly-defined PICOS (patients, interventions, controls, outcome, and study design) criteria were included. The process involved two groups of participants: (i): 'a clinical guidance group' of 18 UK experts (including junior support) who performed the systematic reviews and produced summary evidence statements (SES) based strictly on data synthesis in each review. The same group then produced prototype graded practice recommendations (GPRs) based on coalescence of SES and expert opinion; (ii): a European Consensus group of 18 ESCP (European Society of Coloproctology) nominated experts from nine European countries evaluated the appropriateness of each prototype GPR based on published RAND/UCLA methodology.

RESULTS

An overview of the search results is provided in this manuscript. A total of 156 studies from 307 full text articles (from 2551 initially screened records) were included, providing data on procedures characterized by: (i) colonic resection (n = 40); (ii) rectal suspension (n = 18); (iii) rectal wall excision (n = 44); (iv) rectovaginal septum reinforcement (n = 47); (v) sacral nerve stimulation (n = 7). The overall quality of evidence was poor with 113/156 (72.4%) studies providing only Oxford level IV evidence. The best evidence was extracted for rectal excisional procedures, where the majority of studies were Oxford level I or II. The five subsequent reviews provide a total of 99 SES (reflecting perioperative variables, efficacy, harms and prognostic variables) that contributed to 100 prototype GPRs covering patient selection, procedural considerations and patient counselling. The final manuscript details the 85/100 GPRs that were deemed appropriate by European Consensus (remaining 15 were all uncertain) and future research recommendations.

CONCLUSION

This manuscript and the following 6 papers suggest that the evidence base for surgical management of chronic constipation is currently poor although some expert consensus exists on best practice. Further studies are required to inform future commissioning of treatments and of research funding.

Surgery for constipation: systematic review and practice recommendations: Results IV: Recto-vaginal reinforcement procedures

AIM

To assess the outcomes of recto-vaginal reinforcement procedures in adults with chronic constipation.

METHOD

Standardised methods and reporting of benefits and harms were used for all CapaCiTY reviews that closely adhered to PRISMA 2016 guidance. Main conclusions were presented as summary evidence statements with a summative Oxford Centre for Evidence-Based Medicine (2009) level.

RESULTS

Forty-three articles were identified, providing data on outcomes in 3346 patients. Average length of procedures ranged between 20 and 169 min, and length of stay between 1 and 15 days. Complications typically occurred after 7-17% of procedures (range 0-61%). Post-operative bleeding was uncommon (0-4%) as well as haematoma or sepsis (0-2%). Fistulation did not occur in most studies. Two procedure-related deaths were observed for 3209 patients. Although inconsistent, 78% of patients reported a satisfactory or good outcome, with 30-50% experiencing reduced symptoms of straining, incomplete emptying or reduced vaginal digitation. About 17% of patients developed anatomical recurrence. Considering measures of harm and global satisfaction rating scales, there was insufficient evidence to prefer one type of procedure over another. There was no evidence to support better outcomes based on selection of patients with a particular size or grade of rectocoele.

CONCLUSION

Evidence supporting recto-vaginal reinforcement procedures is currently derived from observational studies and comparisons, with only one high quality study. Large trials are needed to inform future clinical decision making.

Surgery for constipation: systematic review and practice recommendations: Graded practice and future research recommendations

AIM

This manuscript forms the final of seven that address the surgical management of chronic constipation (CC) in adults. The content coalesces results from the five systematic reviews that precede it and of the European Consensus process to derive graded practice recommendations (GPR).

METHODS

Summary of review data, development of GPR and future research recommendations as outlined in detail in the 'introduction and methods' paper.

RESULTS

The overall quality of data in the five reviews was poor with 113/156(72.4%) of included studies providing only level IV evidence and only four included level I RCTs. Coalescence of data from the five procedural classes revealed that few firm conclusions could be drawn regarding procedural choice or patient selection: no single procedure dominated in addressing dynamic structural abnormalities of the anorectum and pelvic floor with each having similar overall efficacy. Of one hundred 'prototype' GPRs developed by the clinical guideline group, 85/100 were deemed 'appropriate' based on the independent scoring of a panel of 18 European experts and use of RAND-UCLA consensus methodology. The remaining 15 were all deemed uncertain. Future research recommendations included some potential RCTs but also a strong emphasis on delivery of large multinational high-quality prospective cohort studies.

CONCLUSION

While the evidence base for surgery in CC is poor, the widespread European consensus for GPRs is encouraging. Professional bodies have the opportunity to build on this work by supporting the efforts of their membership to help convert the documented recommendations into clinical guidelines.

Quality of life following fistulotomy - short term follow-up

AIM

Anal fistula causes pain and discharge of pus and blood. Treatment by fistulotomy has the highest success, but can risk continence; treatment needs to balance cure with continence. This study assessed the impact of fistulotomy on quality of life (QOL) and continence.

METHOD

Patients selected for fistulotomy prospectively completed the St Mark's Continence Score (full incontinence = 24) and Short Form-36 questionnaires preoperatively at two institutions with an interest in anal fistula. Patients were reassessed 3 months' postoperatively.

RESULTS

There were 52 patients with a median age of 44 (range 19-82) years; 10 were women. Preoperative continence scores were median 0 (range 0-23) and there was no significant difference compared with postoperative scores (median 1, range 0-24). Following fistulotomy QOL was significantly improved in four of eight domains - Bodily Pain (P < 0.001), Vitality (P < 0.01), Social Functioning (P < 0.05) and Mental Health (P < 0.001) - and returned to that of the general population. QOL for patients with intersphincteric fistula improved postfistulotomy, and for those with trans-sphincteric fistula it remained the same. Data were further examined in two groups, with and without deterioration in continence score. Where continence improved postoperatively, QOL improved in three domains; where continence deteriorated QOL improved in two domains (P < 0.05). Patients with postoperative continence scores of < 5 had worse QOL than those scoring 4 or less.

CONCLUSION

QOL significantly improved at 3 months' follow-up after fistulotomy where continence was maintained or a small reduction occurred.

Integrated total pelvic floor ultrasound in pelvic floor defaecatory dysfunction

AIM

Imaging for pelvic floor defaecatory dysfunction includes defaecation proctography. Integrated total pelvic floor ultrasound (transvaginal, transperineal, endoanal) may be an alternative. This study assesses ultrasound accuracy for the detection of rectocele, intussusception, enterocele and dyssynergy compared with defaecation proctography, and determines if ultrasound can predict symptoms and findings on proctography. Treatment is examined.

METHOD

Images of 323 women who underwent integrated total pelvic floor ultrasound and defaecation proctography between 2011 and 2014 were blindly reviewed. The size and grade of rectocele, enterocele, intussusception and dyssynergy were noted on both, using proctography as the gold standard. Barium trapping in a rectocele or a functionally significant enterocele was noted on proctography. Demographics and Obstructive Defaecation Symptom scores were collated.

RESULTS

The positive predictive value of ultrasound was 73% for rectocele, 79% for intussusception and 91% for enterocele. The negative predictive value for dyssynergy was 99%. Agreement was moderate for rectocele and intussusception, good for enterocele and fair for dyssynergy. The majority of rectoceles that required surgery (59/61) and caused barium trapping (85/89) were detected on ultrasound. A rectocele seen on both transvaginal and transperineal scanning was more likely to require surgery than if seen with only one mode (P = 0.0001). If there was intussusception on ultrasound the patient was more likely to have surgery (P = 0.03). An enterocele visualized on ultrasound was likely to be functionally significant on proctography (P = 0.02). There was, however, no association between findings on imaging and symptoms.

CONCLUSION

Integrated total pelvic floor ultrasound provides a useful screening tool for women with defaecatory dysfunction such that defaecatory imaging can avoided in some.

The future of pelvic floor services in the UK

AIM

The study aimed to determine the current state of UK pelvic floor services and to discuss future strategies.

METHOD

A questionnaire developed by the Pelvic Floor Society was sent in 2014 to the 175 colorectal units recognized by the Association of Coloproctology of Great Britain and Ireland. Questions included type of centre, frequency of pelvic floor clinics/interdisciplinary joint pelvic floor clinics/multidisciplinary meetings (MDMs) and workload.

RESULTS

Sixty-seven (38%) centres replied including 75% of units with a consultant who was as member of the Pelvic Floor Society. Of the 67 centres 39% were tertiary centres for pelvic floor surgery (tertiary), 48% performed some pelvic floor surgery (regional) and 13% did not perform any (local). Ninety-six per cent of tertiary referral centres served a population over 500 000. The mean number of whole time equivalent consultants in tertiary centres was 1.03 and 0.77 in regional centres. Eighty per cent of tertiary centres and 56% of regional centres ran pelvic floor clinics. Eighty-four per cent of tertiary referral and 75% of regional units held or attended an MDM. Anal ultrasonography, anorectal physiology and proctography were performed in 96% of tertiary centres compared with 50% of non-tertiary units.

CONCLUSION

The provision of pelvic floor services includes local, regional and tertiary centres. The overall response rate was low (38%) and biased to centres with a consultant who was a member of the Pelvic Floor Society. Not all regional or tertiary centres held an MDM or a pelvic floor clinic. Given the nature of pelvic floor pathology an integrated service should be aimed at linking different centres and specialities.

Synchronized functional anal sphincter assessment: maximizing the potential of anal vector manometry and 3-D anal endosonography

BACKGROUND

Understanding the association between structure and function is vital before considering surgery involving anal sphincter division. By correlating three-dimensional anal endosonography (AES) and three-dimensional anal canal vector volume manometry (VVM), this study details a method to produce measurements of both sphincter length and pressure leading to identification of the functionally important areas of the anal canal. The aim of this study was to provide combined detailed information on anal canal anatomy and physiology.

METHODS

Twelve males and 12 nulliparous females with no bowel symptoms underwent VVM (using a water-perfused, eight-channel radially arranged catheter) and AES.

KEY RESULTS

The synchronization of AES and VVM identified that the majority of rest and squeeze anal pressure is present in the portion of the anal canal covered by both anal sphincters. Nearly, 20% of overall resting anal pressure is produced distal to the caudal termination of the internal anal sphincter. Puborectalis accounts for a significantly greater percentage volume of pressure in females both at rest and when squeezing, though the total volume of pressure is not significantly greater.

CONCLUSIONS AND INFERENCES

The majority of resting and squeezing pressure and the least asymmetry, in both sexes, is in the portion of the anal canal covered by external anal sphincter. In females, the external anal sphincter is shorter and a proportionately longer puborectalis accounts for a greater percentage of pressure. Sphincter targeted fistula surgery in females must be performed with special caution. A protective role for puborectalis following obstetric anal sphincter injury is suggested.

Quality of life with anal fistula

INTRODUCTION

Anal fistula affects people of working age. Symptoms include abscess, pain, discharge of pus and blood. Treatment of this benign disease can affect faecal continence, which may, in turn, impair quality of life (QOL). We assessed the QOL of patients with cryptoglandular anal fistula.

METHODS

Newly referred patients with anal fistula completed the St Mark's Incontinence Score, which ranges from 0 (perfect continence) to 24 (totally incontinent), and Short form 36 (SF-36) questionnaire at two institutions with an interest in anal fistula. The data were examined to identify factors affecting QOL.

RESULTS

Data were available for 146 patients (47 women), with a median age of 44 years (range 18-82 years) and a median continence score of 0 (range 0-23). Versus population norms, patients had an overall reduction in QOL. While those with recurrent disease had no difference on continence scores, QOL was worse on two of eight SF-36 domains (p<0.05). Patients with secondary extensions had reduced QOL in two domains (p<0.05), while urgency was associated with reduced QOL on five domains (p<0.05). Patients with loose seton had the same QOL as those without seton. No difference in urgency was found between patients with and without loose seton. In primary fistula patients, 19.4% of patients experienced urgency versus 36.3% of those with recurrent fistulas.

CONCLUSIONS

Patients with anal fistula had a reduced QOL, which was worse in those with recurrent disease, secondary extensions and urgency. Loose seton had no impact on QOL.

Mutations of FLT3/ITD confer resistance to multiple tyrosine kinase inhibitors

FMS-like tyrosine kinase 3 (FLT3) normally functions in the survival/proliferation of hematopoietic stem/progenitor cells, but its constitutive activation by internal tandem duplication (ITD) mutations correlates with a poor prognosis in AML. The development of FLT3 tyrosine kinase inhibitors (TKI) is a promising strategy, but resistance that arises during the course of treatment caused by secondary mutations within the mutated gene itself poses a significant challenge. In an effort to predict FLT3 resistance mutations that might develop in patients, we used saturation mutagenesis of FLT3/ITD followed by selection of transfected cells in FLT3 TKI. We identified F621L, A627P, F691L and Y842C mutations in FLT3/ITD that confer varying levels of resistance to FLT3 TKI. Western blotting confirmed that some FLT3 TKI were ineffective at inhibiting FLT3 autophosphorylation and signaling through MAP kinase, STAT5 and AKT in some mutants. Balb/c mice transplanted with the FLT3/ITD Y842C mutation confirmed resistance to sorafenib in vivo but not to lestaurtinib. These results indicate a growing number of FLT3 mutations that are likely to be encountered in patients. Such knowledge, combined with known remaining sensitivity to other FLT3 TKI, will be important to establish as secondary drug treatments that can be substituted when these mutants are encountered.

Predictive performance of Acute Physiological and Chronic Health Evaluation releases II to IV: a single New Zealand centre experience

There is debate in Australia and New Zealand around the appropriate use of illness severity scoring systems in Australasian intensive care units. The international benchmark is the Acute Physiological and Chronic Health Evaluation (APACHE) system. In order to compare the performance of recent APACHE releases, we audited 2080 sequential patients admitted between 1 January 2006 and 31 March 2008 to the Middlemore Hospital intensive care unit, Auckland, New Zealand. We compared the predictive performance of the proprietary APACHE II, IIIh, IIIj and IV releases, and the performance of a 'localised' version of APACHE II containing re-estimated coefficients derived from a legacy dataset (7703 sequential patients admitted between 1 January 1997 and 31 December 2005). Discrimination assessed by receiver operating characteristic curves was highest with the APACHE III and IV releases, and significantly better than the APACHE II releases. Calibration assessed by the Hosmer-Lemeshow statistic was poor with all releases, although it was best with APACHE IV and 'localised' version of the APACHE II release. Overall accuracy assessed by the Brier Mean Probability score and Shapiro's R statistic was best with APACHE IV. Our study suggests the possibility of improved prediction in moving to APACHE IV from older releases, although broader multicentre study within the Australian and New Zealand critical care community is warranted. Our study also suggests localisation of the APACHE system offers further opportunity to improve prediction, although these improvements may not be major without ground-up development of a new risk prediction model within our local critical care setting.

Comparison of outcomes by modality for critically ill patients requiring renal replacement therapy: a single-centre cohort study adjusting for time-varying illness severity and modality exposure

Prolonged intermittent renal replacement therapy (PIRRT) is a recently defined acute modality for critically ill patients, and in theory combines the superior detoxification and haemodynamic stability of continuous renal replacement therapy (CRRT) with the operational convenience and low cost of intermittent haemodialysis (iHD). We performed a retrospective cohort study for all critically ill adults treated with renal replacement therapy at our centre in Auckland, New Zealand from 1 January 2002 to 31 December 2008. The exposure of interest was modality (PIRRT, CRRT, iHD). Primary and secondary outcomes were patient mortality determined at hospital discharge and 90 days post renal replacement therapy inception, respectively. Co-variates included co-morbidity and baseline illness severity measured by Acute Physiology and Chronic Health Evaluation IV and Sepsis-Related Organ Failure Assessment (SOFA) and time-varying illness severity measured by daily SOFA scores. We used Marginal Structural Modelling to estimate mortality risk adjusting for both time-varying illness severity and modality exposure. A total of 146 patients with 633 treatment-days had sufficient data for modelling. With PIRRT as the reference, the adjusted hazard ratios for patient hospital mortality were 1.31 (0.60 to 2.90) for CRRT and 1.22 (0.21 to 2.29) for iHD. Corresponding estimates for mortality at 90 days were 0.96 (0.39 to 2.36) and 2.22 (0.49 to 10.11), respectively, reflecting the poorer longer-term prognosis of patients still on iHD at hospital discharge with delayed or non-recovery of acute kidney injury. Our study supports the recent increased use of PIRRT, which within limits can be regarded as safe and effective.

Vector volume manometry--methods and normal values

BACKGROUND

Vector volume manometry (VVM) can be used to assess patients with fecal incontinence. The VVM may be performed using a station pull through, or an automated technique. Currently no standard technique or equipment exists to assess anal canal VVM. This study aimed to assess the different techniques to produce repeatable results, and generate normal values for the vector volume profile.

METHODS

Anal canal VVM was performed using a water-perfused system on 12 male and 12 nulliparous female volunteers. Manometry was performed with an automated puller withdrawn at 3 and 25mms(-1) using a station technique. The VVM profiles were calculated using 4, 8, and 16 channels.

KEY RESULTS

The greatest repeatability of vector volume profile was seen with faster puller speed (25mms(-1) ) and with an 8-channel catheter. Men had higher squeeze volumes, maximal squeeze pressure, average squeeze pressure, and squeeze high pressure zone length. Women had a significantly greater anal canal asymmetry on both station and automated pull through at rest and when squeezing. Squeeze vector volume of pressure, mean maximum squeeze pressure, and the average squeeze pressure were significantly higher when calculated using the station technique.

CONCLUSIONS & INFERENCES

The faster puller speed has improved agreement between vector profiles, which is most marked during active contraction. The 8-channel catheters have the greatest agreement between profiles. There is variation in values between automated manometry and the stationary pull through technique. The improved repeatability in automated VVM for healthy controls should improve its diagnostic utility in patients with incontinence.

Short- and long-term outcome of laparostomy following intra-abdominal sepsis

AIM

This study reports the short- and long-term outcomes of laparostomy for intra-abdominal sepsis.

METHOD

Twenty-nine sequential patients with intra-abdominal sepsis treated with a laparostomy over 6 years were included.

RESULTS

The median age of the patients was 51 years, postoperative intensive care unit stay was 8 days, postoperative length of hospital stay was 87 days and follow up was 2 years. The expected mortality of 25% was insignificantly different from the observed mortality of 33% (P = 0.35). Seven per cent of patients required percutaneous drainage of intra-abdominal collections. An enterocutaneous fistula developed in 31% of all patients and in 15% of those treated with vacuum dressings. Component-separation fascial reconstruction was successful and uncomplicated in 83% of recipients compared with 25% of mesh repairs.

CONCLUSION

Laparostomy does not significantly reduce mortality from the expected rate and commits the patient to a prolonged recovery with a high risk of enterocutaneous fistulation. Component-separation fascial reconstruction has a better outcome than mesh repair.

Use of myocutaneous flaps for perineal closure following abdominoperineal excision of the rectum for adenocarcinoma

INTRODUCTION

Abdominoperineal excision (APE) following radiotherapy is associated with a high rate of perineal wound complications. The use of myocutaneous flaps may improve wound healing. We present our experience using myocutaneous flaps for immediate reconstruction.

METHOD

Prospective data were collected on patients undergoing APE from October 2003 to December 2008. Patient demographics, operating time, wound complications and length of stay were recorded.

RESULTS

Fifty-one patients underwent APE for rectal adenocarcinoma, 21 had primary closure and 30 had myocutaneous flap closure (24 VRAM, 6 gracilis). The proportion of patients undergoing preoperative radiotherapy in each group were 62% and 93% respectively (P = 0.011). There were no major complications following primary closure of the unirradiated perineum. Major perineal wound complications requiring reoperation or debridement were seen in three (14%) patients following primary closure and five (17%) patients with flap closure. After radiotherapy, closure with a flap reduced the length of stay from 20 to 15 days, but this difference was not statistically significant (P = 0.36).

CONCLUSION

The use of flap closure in irradiated patients is associated with fewer perineal complications and a shorter hospital stay.

Outcome of patients on renal replacement therapy after colorectal surgery

PURPOSE

Patients on renal replacement therapy are reported to have a high complication rate after abdominal surgery, the result of uremia and immunosuppression. A review of this group of patients undergoing colorectal surgery was undertaken.

METHODS

Seventy-three separate colorectal operations were performed for 44 patients. Thirty-eight patients were on dialysis and 35 had a renal transplant. Data (coexisting disease, preoperative blood results, operative details, complications, and colorectal POSSUM score) were completed for each surgical event.

RESULTS

Forty-two elective and 31 emergency procedures were performed. Infective complications were common (overall 60 percent). There were two anastomotic leaks in the elective group, but five leaks from seven emergency anastomoses. Stomas were frequently raised. Ninety percent of patients who survived and had a defunctioning stoma underwent a successful reversal. The overall major complication rate after elective and emergency surgery was 19 and 81 percent, respectively, and mortality was 5 and 26 percent, respectively.

CONCLUSIONS

Renal patients have a high rate of complications after colorectal surgery, and emergency surgery has a significant risk of anastomotic leak. Primary anastomosis should be avoided in all patients undergoing emergency intestinal resections. Subsequent surgery to restore intestinal continuity is possible in 90 percent of patients with far fewer complications.

Effect of commercial airline travel on oxygen saturation in athletes

BACKGROUND

Aircraft cabins are pressurised to maximum effective altitudes of 2440 metres, resulting in significant decline in oxygen saturation in crew and passengers. This effect has not been studied in athletes.

OBJECTIVE

To investigate the degree of decline in oxygen saturation in athletes during long-haul flights.

METHODS

A prospective cross-sectional study. National-level athletes were recruited. Oxygen saturation and heart rate were measured with a pulse oximeter at sea level before departure, at 3 and 7 hours into the flight, and again after arrival at sea level. Aircraft cabin pressure and altitude, cabin fraction of inspired oxygen and true altitude were also recorded.

RESULTS

45 athletes and 18 healthy staff aged between 17 and 70 years were studied on 10 long-haul flights. Oxygen saturation levels declined significantly after 3 hours and 7 hours (3-4%), compared with sea level values. There was an associated drop in cabin pressure and fraction of inspired oxygen, and an increase in cabin altitude.

CONCLUSIONS

Oxygen saturation declines significantly in athletes during long-haul commercial flights, in response to reduced cabin pressure. This may be relevant for altitude acclimatization planning by athletes, as the time spent on the plane should be considered time already spent at altitude, with associated physiological changes. For flights of 10-13 hours in duration, it will be difficult to arrive on the day of competition to avoid the influence of these changes, as is often suggested by coaches.

Rewarming of healthy volunteers after induced mild hypothermia: a healthy volunteer study

OBJECTIVES

The study compares the efficacy of two active and one passive warming interventions in healthy volunteers with induced mild hypothermia.

METHODS

Eight volunteers were studied in a random order crossover design. Each volunteer was studied during re-warming from a core temperature of 35 degrees C with each of: a radiant warmer (Fisher & Paykel); a forced air warmer (Augustine Medical), and a polyester filled blanket, to re-warm.

RESULTS

No significant differences in re-warming rates were observed between the three warming devices. It was found that the subject's endogenous heat production was the major contributor to the re-warming of these volunteers. Metabolic rates of over 350 W were seen during the study.

CONCLUSIONS

For patients with mild hypothermia and in whom shivering is not contraindicated our data would indicate that the rate of re-warming would be little different whether a blanket or one of the two active devices were used. In the field, this may provide the caregiver a useful choice.

Potential clinical implications of direction of a trans-sphincteric anal fistula track

Background

The longitudinal direction of a trans-sphincteric anal fistula track through the anal sphincter complex may have implications regarding fistulotomy.

Methods

The angle of the track of trans-sphincteric fistulas relative to the longitudinal axis of the anal canal was measured before operation by means of magnetic resonance imaging (MRI) in 46 patients. This was compared with the findings at operation.

Results

The track passed cranially as well as laterally at an acute angle (less than 90°) in 23 patients while it passed either transversely or caudally at an obtuse angle (90° or more) in the remaining 23. The internal opening was significantly higher in relation to the dentate line (above in eight patients, at the dentate line in 14 and below in one patient) when the track was acute than when it was obtuse (above in one, at the dentate line in 17 and below in five patients) (P = 0·004). The fistula track crossed the sphincter at a median angle of 35°, 95° and 132° from internal openings sited above, at and below dentate line level respectively (P = 0·002).

Conclusion

Fistula tracks passed cranially and laterally through the sphincter complex in half of these patients, and were most acutely angled on MRI when internal openings were situated above the dentate line. Preoperative MRI might alert surgeons to the potential hazard of fistulotomy being more extensive than anticipated from simple palpation of the level of the internal opening.

Magnetic resonance imaging for primary fistula in ano

BACKGROUND

This was a prospective study designed to determine the therapeutic impact of magnetic resonance imaging (MRI) in primary fistula in ano, and to assess its effect on outcome.

METHODS

Thirty patients with suspected primary fistula in ano underwent preoperative MRI, and the findings were revealed during surgery following examination under anaesthesia (EUA). Any effect on operative approach was noted. Outcome was assessed at a median of 12 months.

RESULTS

Two patients had sinuses, one had no sepsis and 27 had fistulas: five superficial, seven intersphincteric, 14 trans-sphincteric and one suprasphincteric. MRI and EUA agreed in 15 patients and MRI findings altered the surgical approach in a further three (10 per cent); two of the latter patients were believed to have a sinus at EUA, which MRI correctly identified as a fistula, allowing definitive treatment. The therapeutic impact of MRI was therefore 10 per cent. Persisting disagreement between MRI and EUA in 12 patients mostly related to minor discrepancies in classification. Only one patient required further unplanned surgery, which was for skin-bridging rather than any new sepsis.

CONCLUSION

In experienced hands, MRI has a therapeutic impact of 10 per cent for primary fistula in ano, precipitating surgery that is likely to reduce recurrence in a small, but important, proportion of patients.

The clinical course of fistulating Crohn's disease

AIM

To determine the clinical characteristics, management and outcome of Crohn's fistulas from the time of first presentation.

METHODS

Patients treated for fistulas 6 years previously were assessed for disease demographics, fistula characteristics and treatment from first presentation to final follow-up.

RESULTS

Eighty-seven patients with active Crohn's fistulas were evaluated. The median age was 35 years and the median duration of Crohn's disease was 8 years at study entry. Disease was ileo-colonic or colonic in 85%, and 65% had rectal involvement. A single fistula was present in one-third and multiple fistulas in two-thirds; 65% of fistulas were perianal; 80% of fistulas were complex. After a median follow-up from the last treatment of 5.9 years, 68% of patients showed healing of all fistulas, 18% showed healing of some fistulas and 14% showed no healing of fistulas. The fistula site did not influence healing. Perianal and recto-vaginal fistulas took a median of 2.6 years to heal. Half of the complex fistulas required a stoma, resection or proctectomy.

CONCLUSIONS

Healing is usually achieved. However, morbidity is great and healing is slow. Proctectomy is required in one-fifth of patients, and perineal healing is often slow. Defining the perianal fistula anatomy as complex or simple determines the likelihood of healing and the type of surgical approach required.

The clinical course of fistulating Crohn's disease

AIM

To determine the clinical characteristics, management and outcome of Crohn's fistulas from the time of first presentation.

METHODS

Patients treated for fistulas 6 years previously were assessed for disease demographics, fistula characteristics and treatment from first presentation to final follow-up.

RESULTS

Eighty-seven patients with active Crohn's fistulas were evaluated. The median age was 35 years and the median duration of Crohn's disease was 8 years at study entry. Disease was ileo-colonic or colonic in 85%, and 65% had rectal involvement. A single fistula was present in one-third and multiple fistulas in two-thirds; 65% of fistulas were perianal; 80% of fistulas were complex. After a median follow-up from the last treatment of 5.9 years, 68% of patients showed healing of all fistulas, 18% showed healing of some fistulas and 14% showed no healing of fistulas. The fistula site did not influence healing. Perianal and recto-vaginal fistulas took a median of 2.6 years to heal. Half of the complex fistulas required a stoma, resection or proctectomy.

CONCLUSIONS

Healing is usually achieved. However, morbidity is great and healing is slow. Proctectomy is required in one-fifth of patients, and perineal healing is often slow. Defining the perianal fistula anatomy as complex or simple determines the likelihood of healing and the type of surgical approach required.

Response of fistulating Crohn's disease to infliximab treatment assessed by magnetic resonance imaging

AIMS

To assess fistula track healing after infliximab treatment using magnetic resonance imaging.

METHODS

Magnetic resonance imaging and clinical evaluation were performed before and after three infliximab infusions given over a 6-week period. Magnetic resonance images were evaluated for abscesses and fistula tracks. Paired magnetic resonance image examinations were rated 'better', 'unchanged' or 'worse'. Magnetic resonance imaging and clinical outcomes were then compared.

RESULTS

Of the 12 referred patients, pre-treatment magnetic resonance imaging detected abscesses in three (two not treated). Of the 10 treated patients, seven had peri-anal fistulas, two of whom also had recto-vaginal fistulas, and three had abdominal wall entero-cutaneous fistulas. After infliximab, four were in remission, one had a response and five were non-responders. One developed a peri-anal abscess. Magnetic resonance imaging improved in six, was unchanged in two and was worse in two. In four of the six with improvement in magnetic resonance imaging, the fistula track resolved, but two of these had clinically persistent entero-cutaneous fistulas. The clinical outcome and magnetic resonance imaging correlated in seven of the 10 patients; in three (two entero-cutaneous and one peri-anal), there was discordance.

CONCLUSIONS

Magnetic resonance imaging identifies clinically silent sepsis. Fistulas may persist despite clinical remission. Clinical response to infliximab and clinical correlation with magnetic resonance imaging were poor in patients with abdominal entero-cutaneous fistulas.

Home-based study of anti-HIV drug regimen adherence among HIV-infected women: feasibility and preliminary results

Collection of antiretroviral medication adherence data in the homes of HIV-infected people may have methodological advantages that can improve data quality. However, the feasibility of this approach has not been established. In addition, data on adherence, and its predictors, among HIV-infected women have been limited. Sixty-three HIV-positive women who were prescribed at least one antiretroviral drug in the last month were interviewed in their homes. A standard instrument was used to collect data on all antiretroviral medications prescribed and taken in the three days prior to the interview. Data were also collected on factors thought potentially to affect the ability to be adherent. The results of this study suggest that it is feasible to conduct home-based adherence research. Sixty-seven per cent reported taking all prescribed antiretroviral medication doses. One-third took a sub-optimal dose putting themselves at increased risk of treatment failure and the selection of resistant HIV strains. Unintentional reasons for missing doses were most commonly reported. An ability to describe the intended effect of antiretroviral therapy on HIV viral load was the best predictor of adherence. This finding is consistent with other research suggesting that adherence is associated with an understanding and belief in the effectiveness of antiretroviral therapy.

Alteration of anal sphincter morphology following vaginal delivery revealed by multiplanar anal endosonography

OBJECTIVE

To assess morphologic change in the anal sphincters in the absence of endosonographic evidence of trauma after vaginal delivery.

DESIGN

Prospective observational study.

SETTING

District general hospital.

POPULATION

Consecutively booked nulliparous pregnant women attending antenatal clinic.

METHODS

All women were examined using three-dimensional anal endosonography, simple manometry and had questionnaire assessment of incontinence before and after delivery.

MAIN OUTCOME MEASURES

Components of the anal canal were measured in the axial, sagittal and coronal planes and paired pre- and post-delivery examinations were compared. Any changes were related to changes in continence and anal canal manometry.

RESULTS

Twenty-two women had a vaginal delivery and no endosonographic evidence of perineal trauma after delivery. After delivery, there was significant shortening of the length of the anterior external anal sphincter [EAS] (mean 21.7 vs 20.5 mm, P = 0.02) when measured in the sagittal plane, which increased in anterior angulation with respect to the axis of the anal canal (10 degrees vs 13.8 degrees, P = 0.03). In the axial plane, no change was seen in the thickness of any of the sphincter components after delivery. None of these morphologic changes correlated with changes in manometry or continence score.

CONCLUSIONS

Anal sphincter morphology changes after an otherwise atraumatic vaginal delivery. This change does not correlate with any functional symptoms.

Assessment of third degree tears using three-dimensional anal endosonography with combined anal manometry: a novel technique

Three-dimensional anal endosonography has enabled sagittal and coronal reconstructions of the anal canal to be matched with longitudinal pressure data, to present a combined picture of structure and function. This novel technique has been applied to a group of women with a clinical diagnosis of a third degree tear. Endosonography showed that only 68% of women had ultrasound evidence of sphincter damage. Anal canal anatomy and pressure profile did not differ significantly between those with and those without sphincter damage, but the anterior external anal sphincter and the puborectalis tended to be shorter and the pressures were lower in those with sphincter disruption.

Endoanal ultrasound

This pictorial review demonstrates the normal anatomy and abnormalities that are readily demonstrated with endoanal ultrasound of the anal sphincters.

Endosonographic anatomy of the normal anal canal compared with endocoil magnetic resonance imaging

PURPOSE

This study was designed to clarify the sonographic anatomy of the normal anal canal by comparison with endoanal magnetic resonance imaging, to determine agreement between these imaging modalities and interobserver error in measuring layer thickness.

METHODS

Three-dimensional endosonographic and endocoil magnetic resonance images of the anal canal were obtained in four males and five nulliparous females aged 22 to 34 years. Images were analyzed at similar levels throughout the canal using a graphics-overlay technique to compare sonographic with magnetic resonance images. Measurements were taken at one level for agreement analysis between modalities and for interobserver variability in the measurement of the thickness of the main anal canal layers.

RESULTS

The muscularis submucosae ani, muscle bundles in the longitudinal muscle layer, and puboanalis were identified on sonography. The outer border of the external sphincter was demarcated by an interface reflection with ischioanal fat. Clarification of the external sphincter anatomy allowed excellent correlation (Ri = 0.96) for the assessment of thickness. There was excellent correlation for the interobserver measurement of the external and internal sphincters and the submucosal width on endosonography, but there was poor correlation for the longitudinal muscle (0.12).

CONCLUSION

The overlay technique has improved endosonographic interpretation, and measurement of external sphincter thickness has been validated both by comparison with magnetic resonance and on interobserver agreement.

HIV in China

A team of American nurse and physician educators collaborated with the Nursing Department of the Hunan Medical University, Changsha, Hunan Province, People's Republic of China, to develop a "train-the-trainer" program for Chinese nurses. The program included didactic and experiential learning activities intended to increase Chinese nurses' level of comfort when discussing culturally sensitive issues such as sexual behavior and drug use. The program emphasized collaborative development of educational materials that reflected the local cultural content. Chinese nurses responded enthusiastically but remained uncomfortable with sexual information after an initial workshop. Follow-up training programs are essential. Successful HIV/AIDS education requires teachers and students to examine personal and cultural values to address the affective learning domain.

Evaluation of two self-care treatments for prevention of vaginal candidiasis in women with HIV

Vaginal candidiasis (VC) is a common concern for women living with HIV infection. The authors evaluated the effectiveness of two self-care approaches to prophylaxis of VC among HIV-infected women, weekly intravaginal application of Lactobacillus acidophilus or weekly intravaginal application of clotrimazole tablets, in a randomized, double-blind, placebo-controlled trial. VC was defined as a vaginal swab positive for Candida species in the presence of signs/symptoms of vaginitis and the absence of a diagnosis of Trichomonas vaginalis or bacterial vaginosis. Thirty-four episodes of VC occurred among 164 women followed for a median of 21 months. The relative risk of experiencing an episode of VC was 0.4 (95% CI = 0.2, 0.9) in the clotrimazole arm and 0.5 (95% CI = 0.2, 1.1) in the Lactobacillus acidophilus arm. The estimated median time to first episode VC was longer for clotrimazole (p = .03, log rank test) and Lactobacillus acidophilus (p = .09, log rank test) compared with placebo. Vaginal yeast infections can be prevented with local therapy. Education about self-care for prophylaxis of VC should be offered to HIV-infected women.

Assessment of external anal sphincter morphology in idiopathic fecal incontinence with endocoil magnetic resonance imaging

The failure of external anal sphincter repair may relate to sphincter atrophy where muscle fibers are replaced by fat, seen on MRI due to the differing signals returned by fat and muscle tissue. Manometry, electrophysiology, and MRI with an endocoil were performed on 34 fecally incontinent patients with intact sphincters on endosonography. The area of the external sphincter was measured in the midcoronal plane, and the percentage fat content calculated. Sphincter muscle area correlated strongly with squeeze pressure (P < 0.001) but not with percentage fat content. There was no relationship between percentage fat and age, weight, anal sensation, squeeze pressure, sphincter length or width, or pudendal nerve terminal motor latency. There was a trend for smaller sphincters to contain a higher percentage fat content (P = 0.059). MRI has established a relationship between function and external sphincter bulk, but not fat content, although smaller muscles may contain more fat.

Endocoil magnetic resonance imaging quantification of external anal sphincter atrophy

BACKGROUND

Anal function depends on the integrity and quality of the sphincter muscles. The diagnosis of external anal sphincter atrophy on endocoil magnetic resonography has been associated with poor outcome from sphincter repair, although the imaging criteria for atrophy remain unclear.

METHODS

Women with intact sphincters on endosonography and either normal (more than 60 cm H(2)O) (n = 9) or low (n = 16) squeeze pressures had endocoil magnetic resonography and electromyography. The area and fat content of the external anal sphincter and puborectalis were measured on mid-coronal magnetic resonography and images were graded as showing normal, intermediate or advanced atrophy. The definition of the external anal sphincter on endosonography and the thickness of the internal anal sphincter were also assessed.

RESULTS

Women with a normal anal squeeze pressure had a larger external anal sphincter cross-sectional area (mean(s.d.) 240(56) versus 193(62) mm(2); P = 0.01) with a lower mean fat content (mean(s.d.) 23(4) versus 30(6) per cent; P < 0.001) than those with low squeeze pressures. There was an overall correlation between squeeze pressure, cross-sectional area (r = 0.32, P = 0.02) and fat content (r = - 0.51, P < 0.001). Patients with a thin (less than 2 mm) internal anal sphincter and/or a poorly defined external sphincter on endosonography were more likely to have atrophy (positive predictive value 74 per cent).

CONCLUSION

: Potential endosonographic markers for external anal sphincter atrophy are suggested, and a visual scale for endocoil magnetic resonographic assessment has been validated.

Anal sphincter damage after vaginal delivery using three-dimensional endosonography

OBJECTIVE

To determine the incidence and functional consequences of external sphincter trauma compared with other perineal structures using a novel imaging technique, three-dimensional endosonography.

METHODS

Fifty-five nulliparous women (mean age 30 years, range 18--47 years) had three-dimensional anal endosonography, anal manometry, and questionnaire assessment of continence at a median gestation of 33 weeks (23--42 weeks) and 10 weeks (7--22 weeks) after delivery.

RESULTS

There was ultrasound evidence of postpartum trauma in 13 of 45 women who had a vaginal delivery (29%, confidence interval [CI] 16%, 44%), involving the external sphincter in five (11%, CI 4%, 24%), the puboanalis in nine (20%, CI 10%, 35%), and the transverse perineii in three (7%, CI 1%, 18%). In four, more than one structure was damaged. External sphincter trauma was associated with a significant decrease in squeeze pressure (P =.035) and an increase in incontinence score (P =.02) compared with those without trauma. Tears to the puboanalis or transverse perineii only did not affect pressure or incontinence scores. Coronal imaging of the external anal sphincter was a useful adjunct to the assessment of trauma.

CONCLUSION

The overall incidence of trauma to the sphincter complex was similar to that of previous reports, although actual damage to the external sphincter was less common and represented the only functionally significant component.

Multiplanar anal endosonography--normal anal canal anatomy

INTRODUCTION

Volume acquisition during anal ultrasound enables multiplanar imaging of the anal canal. The normal ultrasonic multiplanar appearance of the anal canal is described and gender differences in canal anatomy are highlighted.

METHODS

Ten male and 12 female normal volunteers (mean ages 31.5 years (s.d. 5.9) and 31.2 (s.d. 6.7)) had three-dimensional anal endosonography (3-D AES). Each volume dataset was seeded in the axial plane facilitating multiplanar identification of known anatomical structures.

RESULTS

The anterior external anal sphincter (EAS) was significantly longer in men than women 30.1 mm (3.9) vs 16.9 mm (7.4) (P < 0.001). There was no difference in the length of the puborectalis 24.7 mm (6.4) vs 24 mm (5) (P=0.78) in men compared with women. The cranial extent of the anterior EAS was tilted forward in both sexes. The angle formed by the anterior EAS and the longitudinal axis of the anal canal was more acute in men than in women (11.1 degrees vs 18.6 degrees; P=0.007). Dataset volume seeding of familiar structures in the axial plane allowed the multiplanar endosonographic anatomy to be described.

CONCLUSIONS

Multiplanar AES has enabled detailed longitudinal measurement of the components of the anal canal and has revealed important gender differences. The multiplanar ultrasonic appearance of the normal anal canal has been described for the first time.

Dantrolene reduces serum TNFalpha and corticosterone levels and muscle calcium, calpain gene expression, and protein breakdown in septic rats

The effects of dantrolene on serum TNFalpha and corticosterone levels and on muscle calcium, calpain gene expression, and protein breakdown were studied in rats with abdominal sepsis induced by cecal ligation and puncture. Treatment of rats with 10 mg/kg of dantrolene 2 h before and 8 h after induction of sepsis reduced serum TNFalpha and corticosterone, muscle calcium levels, mRNA levels for m- and mu-calpain, and the muscle specific calpain p94, as well as total and myofibrillar protein breakdown rates, determined as release of tyrosine and 3-methylhistidine, respectively, from incubated extensor digitorum longus muscles. The results support the concept that increased calcium concentrations may be an important mechanism of sepsis-induced muscle protein breakdown. The data also indicate that other mechanisms, in addition to reduced muscle calcium concentrations such as decreased levels of TNFalpha and glucocorticoids, may contribute to the anti-catabolic effects of dantrolene during sepsis. The observations are important from a clinical standpoint because they suggest that the catabolic response in skeletal muscle during sepsis may be prevented by treatment with a calcium antagonist.

Prospective assessment of interobserver agreement for endoanal MRI in fecal incontinence

BACKGROUND

Endoanal magnetic resonance (MR) imaging is a new technique for the assessment of anal sphincter integrity in fecal incontinence and an alternative to anal endosonography. The present study aimed to determine interobserver variation for assessment of anal sphincter integrity using endoanal MR imaging.

METHODS

Fifty-two consecutive anally incontinent patients underwent MR imaging by using a purpose-built endoanal receiver coil and static 1.0-T magnet. T2-weighted axial, coronal, and sagittal scans were independently assessed by two radiologists who noted external and internal sphincter integrity. Findings were compared and agreement was assessed with the kappa statistic.

RESULTS

There was disagreement in 18 of 49 technically adequate studies (37%; kappa = 0.46), indicating "moderate" agreement. Agreement was strongest if the sphincters were either both intact or both disrupted. Observers agreed in only one diagnosis of an isolated internal sphincter defect and in no diagnosis of an isolated external sphincter defect.

CONCLUSION

The overall interobserver agreement for assessment of sphincter integrity using endoanal MR imaging is "moderate." Interobserver agreement using endoanal MR imaging is less than that reported for anal endosonography.

Gender differences in the longitudinal pressure profile of the anal canal related to anatomical structure as demonstrated on three-dimensional anal endosonography

BACKGROUND

Anal canal squeeze pressure is assumed to be due to external sphincter contraction, but the contribution of other muscles has not been explored.

METHODS

Ten male and ten nulliparous female asymptomatic subjects had three-dimensional anal endosonography and manometry. Incremental squeeze pressures at 0. 5-cm intervals, expressed as a percentage of the maximum pressure recorded anywhere in the canal, were related to the following anatomical levels: puborectalis, overlap between external anal sphincter (EAS) and puborectalis, external and internal anal sphincters, and external anal sphincter only. Levels were determined by coronal and sagittal endosonographic reconstructions.

RESULTS

Puborectalis was the same length in men and women (median 23.9 versus 27.1 mm) but represented a greater proportion of the anal canal in women (45 versus 61 per cent; P = 0.02). At the level of puborectalis alone, the pressure generated as a proportion of maximum anal canal pressure was 71 (range 32-100) per cent in men and 62 (range 32-100) per cent in women. At the level of the EAS alone, the pressure was 60 (4-98) per cent in men and 82 (41-100) per cent in women; where the external sphincter was overlapped by puborectalis, the pressure was 98 (60-100) per cent in men and 75 (47-100) per cent in women.

CONCLUSION

Maximal anal canal squeeze pressure is found where the puborectalis overlaps the EAS. This segment represents a significant proportion of anal canal length in women.

Prospective assessment of accuracy of endoanal MR imaging and endosonography in patients with fecal incontinence

OBJECTIVE

Endoanal MR imaging was prospectively compared with anal endosonography to determine any superiority in the characterization of sphincter morphology in fecal incontinence.

SUBJECTS AND METHODS

Fifty-two consecutive patients with fecal incontinence were examined with anal endosonography and endoanal MR imaging after a detailed bowel history, clinical examination, and complete anorectal physiologic testing. External and internal anal sphincter integrity was noted on both endosonograms and MR images by two radiologists in consensus, who read individual scans in a random order to avoid recall bias. Imaging findings were subsequently compared, and arbitration of any disagreement between endosonography and MR imaging was made in consensus by a surgeon and a gastroenterologist who also had access to the patient's history, clinical examination, and anorectal physiologic testing results.

RESULTS

Complete agreement was found between anal endosonographic and MR imaging interpretations in 32 patients (62%): 10 with combined external and internal sphincter injuries, two with isolated internal sphincter injury, and 20 with intact sphincters. Of 20 patients in whom results of the scans were disparate, incorrect interpretation was found on endosonography in six patients, on MR imaging in 15. Overall, one error relating to the internal sphincter was made on endosonography versus 12 on MR imaging (p = 0.002), and five errors relating to the external sphincter were made on endosonography versus six on MR imaging (p = 1.0).

CONCLUSION

This study suggests that endoanal sonography and endoanal MR imaging are equivalent in diagnosing external anal sphincter injury, but MR imaging is inferior in diagnosing internal anal sphincter injury.

Sepsis stimulates release of myofilaments in skeletal muscle by a calcium-dependent mechanism

Sepsis is associated with a pronounced catabolic response in skeletal muscle, mainly reflecting degradation of the myofibrillar proteins actin and myosin. Recent studies suggest that sepsis-induced muscle proteolysis may reflect ubiquitin-proteasome-dependent protein breakdown. An apparently conflicting observation is that the ubiquitin-proteasome pathway does not degrade intact myofibrils. Thus, it is possible that actin and myosin need to be released from the myofibrils before they can be ubiquitinated and degraded by the proteasome. We tested the hypothesis that sepsis results in disruption of Z-bands, increased expression of calpains, and calcium-dependent release of myofilaments in skeletal muscle. Sepsis induced in rats by cecal ligation and puncture resulted in increased gene expression of micro-calpain, m-calpain, and p94 and in Z-band disintegration in the extensor digitorum longus muscle. The release of myofilaments from myofibrillar proteins was increased in septic muscle. This response to sepsis was blocked by treating the rats with dantrolene, a substance that inhibits the release of calcium from intracellular stores to the cytoplasm. The present results provide evidence that sepsis is associated with Z-band disintegration and a calcium-dependent release of myofilaments in skeletal muscle. Release of myofilaments may be an initial and perhaps rate-limiting component of sepsis-induced muscle breakdown.

Kinetics of absorption atelectasis during anesthesia: a mathematical model

Recent computed tomography studies show that inspired gas composition affects the development of anesthesia-related atelectasis. This suggests that gas absorption plays an important role in the genesis of the atelectasis. A mathematical model was developed that combined models of gas exchange from an ideal lung compartment, peripheral gas exchange, and gas uptake from a closed collapsible cavity. It was assumed that, initially, the lung functioned as an ideal lung compartment but that, with induction of anesthesia, the airways to dependent areas of lung closed and these areas of lung behaved as a closed collapsible cavity. The main parameter of interest was the time the unventilated area of lung took to collapse; the effects of preoxygenation and of different inspired gas mixtures during anesthesia were examined. Preoxygenation increased the rate of gas uptake from the unventilated area of lung and was the most important determinant of the time to collapse. Increasing the inspired O2 fraction during anesthesia reduced the time to collapse. Which inert gas (N2 or N2O) was breathed during anesthesia had minimal effect on the time to collapse.