Perioperative cell-free DNA trends predict recurrence of non-metastatic colorectal cancer significantly earlier than CEA trends over the first 2 years post-operatively in stage II and stage III colon cancer

PURPOSE

We aimed to compare the diagnostic accuracy of perioperative ΔcfDNA to ΔCEA (over the first 2 years post-operatively) for identifying disease recurrence in colon cancer.

METHODS

Patients presenting for elective resection for colon cancer with curative intent were screened for inclusion. Perioperative cfDNA levels were measured at seven different times points(pre-operative and post-operative at 3 h, 6 h, 24 h, 48 h, POD3 and POD5). CEA levels were measured on the same patients up to 2 years post-operatively. Change in trend (Δ) was defined as the β coefficient using a logistic regression model. Statistical analysis was performed using SPSS, version 23.

RESULTS

Longitudinal data on twenty-two patients were analysed (n = 16 male, n = 6 female) for a median of 29 months (IQR 23 months) during which time three patients developed (distant) recurrence. Perioperative ΔcfDNA at 48Hrs, POD3 and POD5 were significantly associated with early recurrence. ΔCEA was significantly associated with early recurrence at 6 months, 1 year and 2 years post-operatively, only when disease recurrence was macroscopically established. ΔcfDNA was associated with an area under the curve (AUC) of 0.947 (95% CI 0.88-1.0, p < 0.001) and ΔCEA was associated with an AUC of 0.9382 (95%CI 0.88-0.99, p < 0.0001). This translated into a specificity of 97% (95%CI 86.51-99.87%) for ΔcfDNA and 77.5% sensitivity (95%CI 62.5-87.7%) in the immediate perioperative period and an 88.9% specificity (95%CI 56.5-99.4%) and 76.5% sensitivity (95%CI 63.24-86%) for ΔCEA over the first 2 years post-operatively.

CONCLUSIONS

In this pilot study, following curative resection for colon cancer changing trends in perioperative cfDNA (ΔcfDNA) identify those at risk of recurrent disease before recurrence develops which is at least 6 months earlier than CEA changes (ΔCEA) which are only observed when recurrence is established.

Primary hyperparathyroidism causing posterior reversible encephalopathy syndrome: a case report

Posterior reversible encephalopathy syndrome (PRES) is a reversible leukoencephalopathy characterised by subcortical vasogenic oedema and neurological signs. We present the case of a 64-year-old woman who presented to hospital with symptomatic primary hyperparathyroidism. Her parathyroid hormone (PTH) level on admission was elevated at 1,330ng/l (normal range15-68ng/l) and her serum calcium measured 4.83mmol/l (normal range 2.25-2.54mmol/l). Technectium-99m sestamibi scan demonstrated a focus of radiotracer uptake consistent with a right upper parathyroid adenoma or carcinoma. After commencing appropriate medical treatment, the patient developed intractable seizures necessitating endotracheal intubation. Magnetic resonance imaging of her brain revealed bilateral symmetrical T2 hyperintensities in the posterior circulation consistent with PRES. Following stabilisation and further medical treatment for hypercalcaemia, the patient underwent a parathyroidectomy. Preoperative rapid PTH assay measured 1,021ng/l. Following excision, PTH levels fell to just 10ng/l. She was extubated in the intensive care unit on postoperative day 1 and made an uneventful recovery. At her 6-week follow-up appointment, all neurological symptoms had resolved. PRES is a rare neurological entity more often seen in the setting of hypertension, immunosuppression and renal failure. The development of new neurological manifestations in the setting of known risk factors should raise suspicion for the underlying diagnosis.

P12: PREDICTORS OF CONVERSION FROM MINIMALLY INVASIVE TO OPEN ADRENALECTOMY: A SYSTEMATIC REVIEW & META-ANALYSIS OF OBSERVATIONAL STUDIES

Introduction

Minimally invasive adrenalectomy has become the standard of care internationally in benign adrenal disease. Intra-operative conversion to open surgery is associated with significantly increased morbidity and prolonged hospital stay. The aim of this systematic review is to identify risk factors associated with intra-operative conversion of minimally invasive adrenalectomy.

Method

This systematic review was conducted according to MOOSE guidelines. PubMed, EMBASE and Cochrane library were systematically searched for observational studies evaluating risk factors for intra-operative conversion of minimally invasive adrenalectomy to open surgery. Specific risk factors of interest included patient demographics, patient co-morbidities, tumour characteristics and histology.

Result

Eight studies met the inclusion criteria for analysis with a total of 2939 patients. 6.02% (n=177) required intra-operative conversion. 67.5% (n=1983) underwent laparoscopic transperitoneal adrenalectomy. There were no significant associations between any patient demographics or co-morbidities and intra-operative conversion. Tumour characteristics such as right sided tumours (pooled odds ratio (OR), 1.51; 95% Confidence Interval (CI), 0.98-2.32; p=0.06) and increasing tumour size (OR, 2.29; 95% CI, 1.4-3.74; p=0.001) were shown to be significantly associated with an increased risk of conversion. Pheochromocytoma (OR, 2.21; 95% CI, 1.89-2.58; p&lt;0.0001) and malignancy (OR, 5.38; 95% CI, 2.1-13.81; p=0.005) were also significant predictors of intra-operative conversion.

Conclusion

Minimally invasive adrenalectomy has significantly reduced post-operative morbidity in patients requiring adrenal surgery but the need for intra-operative conversion remains significant. Identifying patients at increased risk of conversion pre-operatively may assist intra-operative decision making and contribute to improved patient outcomes.

Take-home message

Minimally invasive adrenalectomy carries a significant risk of conversion. Recognising patients with known risk factors for conversion aids risk stratification and may contribute to better outcomes.

Role of circulating fibrocytes in the diagnosis of acute appendicitis

Background

Improved diagnostic biomarkers are required for acute appendicitis. The circulating fibrocyte percentage (CFP) is increased in inflammatory states, but has not been studied in acute appendicitis. This study aimed to determine CFP in acute appendicitis and compare diagnostic accuracy with standard serological biomarkers.

Methods

A prospective cohort study was carried out between June 2015 and February 2016 at University Hospital Limerick. The CFP was determined by dual‐staining peripheral venous samples for CD45 and collagen I using fluorescence‐activated cell sorting, and correlated with histopathological diagnoses. The accuracy of CFP in determining histological acute appendicitis was characterized and compared with the white cell count, C‐reactive protein concentration, neutrophil count, lymphocyte count and neutrophil : lymphocyte ratio.

Results

Of 95 adults recruited, 15 were healthy individuals and 80 had suspected appendicitis at presentation. Forty‐six of these 80 patients had an appendicectomy, of whom 34 had histologically confirmed appendicitis. The CFP was statistically higher in patients with pathologically proven acute appendicitis than in healthy controls (median 6·1 (i.q.r. 1·6–11·6) versus 2·3 (0·9–3·4) per cent respectively; P = 0·008). The diagnostic accuracy of CFP, as determined using the area under the receiver operating characteristic (ROC) curve, was similar to that of standard biomarkers. In multinomial regression analysis, only raised CFP was retained as an independent prognostic determinant of acute appendicitis (odds ratio 1·57, 95 per cent c.i. 1·05 to 2·33; P = 0·027).

Conclusion

The CFP is increased in histologically confirmed acute appendicitis and is as accurate as standard serological biomarkers in terms of diagnosis.

Longer small bowel segments are resected in emergency surgery for ileocaecal Crohn's disease with a higher ileostomy and complication rate

BACKGROUND

Repeated intestinal resections may have disabling consequences in patients with Crohn's disease even in the absence of short bowel syndrome. Our aim was to evaluate the length of resected small bowel in patients undergoing elective and emergency surgery for ileocolic Crohn's disease.

METHODS

A prospective observational study was conducted on patients undergoing surgery for ileocolonic Crohn's disease in a single colorectal centre from May 2010 to April 2018. The following patients were included: (1) patients with first presentation of ileocaecal Crohn's disease undergoing elective surgery; (2) patients with ileocaecal Crohn's disease undergoing emergency surgery; (3) patients with recurrent Crohn's disease of the distal ileum undergoing elective surgery. The primary outcomes were length of resected small bowel and the ileostomy rate. Operating time, complications and readmissions within 30 days were the secondary outcomes.

RESULTS

One hundred and sixty-eight patients were included: 87 patients in the elective primary surgery group, 50 patients in the emergency surgery group and 31 in the elective redo surgery group. Eleven patients (22%) in the emergency surgery group had an ileostomy compared to 10 (11.5%) in the elective surgery group (p < 0.0001). In the emergency surgery group the median length of the resected small bowel was 10 cm longer than into the group having elective surgery for primary Crohn's disease.

CONCLUSIONS

Patients undergoing emergency surgery for Crohn's disease have a higher rate of stoma formation and 30-day complications. Laparoscopic surgery in the emergency setting has a higher conversion rate and involves resection of longer segments of small bowel.

Six-year review of traumatic brain injury in a regional trauma unit: demographics, contributing factors and service provision in Ireland

BACKGROUND

Traumatic brain injury (TBI) represents a significant burden of care for acute surgical services, particularly in the absence of on-site neurosurgical cover or sufficient post-acute rehabilitation facilities. We examine factors contributing to TBI, prolonged lengths of stay (LoS) and implications for hospital resources. Long-term outcomes are assessed.

METHODS

This is a retrospective cohort study of patients admitted to a regional trauma unit with TBI from 2008 to 2013. Patients with LoS > 48 h were assessed. Demographic, clinical and longitudinal mortality data were collected using electronic clinical and radiological systems and chart review.

RESULTS

A total of 690 patients presented with TBI from 2008 to 2013; 213 patients with LoS > 48 h were assessed. One hundred and thirty (61%) were male. Mean age was 56 years (±SD 24). Mechanical fall was the most frequent injury mechanism (n = 120/213, 56%). Twenty-five per cent were associated with alcohol consumption; these were more likely to be male, involved in an Road Traffic Accident (RTA) or assault and necessitate transfer to a neurosurgical unit (p < 0.001, p = 0.029, p < 0.001, p = 0.05). A total of 112 patients(53%) had a prolonged LoS (>2 weeks). Mean LoS was 20 days (±SD 35), increasing to 39 days for patients requiring neurosurgical intervention. The 12-month all-cause mortality rate was 12%.

CONCLUSIONS

TBIs result in significant utilisation of acute inpatient bed days. Improved rehabilitation services and strategies to reduce acute hospital LoS are warranted.

The effect of purse-string approximation versus linear approximation of ileostomy reversal wounds on morbidity rates and patient satisfaction: the 'STOMA' trial

BACKGROUND

Ileostomy reversal is associated with surgical site infection (SSI) rates as high as 37%. Recent literature suggests that employing a purse-string approximation (PSA) of the reversal wound reduces this rate of SSI. Thus we wished to perform a randomised controlled trial to compare SSI rates in purse-string versus linear closure (PLC) wounds following ileostomy reversal.

METHODS

A randomised, controlled trial was conducted at University Hospital Limerick. Sixty-one patients undergoing ileostomy reversal were included. Thirty-four patients were randomised to PSA and 27 patients to linear closure. The primary endpoint was incidence of SSI and secondary endpoints measured were quality of life and satisfaction with cosmesis. Statistical analysis was performed on a per protocol basis using SPSS version 22.0.

RESULTS

Three patients in the PSA group developed an SSI compared to 8 in the PLC group at 30 days (8 vs 30%, p = 0.03). The mean time to SSI diagnosis was faster in the PSA group (3 vs 12.3 days, p = 0.08). Patients who developed SSI experienced a longer mean length of stay (6.8 vs 11.4 days, p = 0.012). On multivariate analysis, PLC was the only predictive factor of SSI formation (p < 0.001). There was no difference in patient satisfaction between the two study groups (p = 0.14).

CONCLUSIONS

PSA of wounds following ileostomy reversal significantly reduces SSI formation compared to linear approximation without any effect on patient satisfaction.

Clinical assessment to determine the risk of bowel cancer using Symptoms, Age, Mass and Iron deficiency anaemia (SAMI)

BACKGROUND

The aim of this study was to identify characteristics with independent predictive value for bowel cancer for use in the clinical assessment of patients attending colorectal outpatient clinics.

METHODS

This was a 22-year (1986-2007) retrospective cohort analysis of data collected prospectively from patients who attended colorectal surgical outpatient clinics in Portsmouth. The data set was split randomly into two groups of patients to generate and validate a predictive model. Multivariable logistic regression was used to create and validate a system to predict outcome. Receiver operating characteristic (ROC) curves and Hosmer-Lemeshow test were used to evaluate the model's predictive capability. The likelihood of bowel cancer was expressed as the odds ratio (OR).

RESULTS

Data from 29 005 patients were analysed. Discrimination of the model for bowel cancer was high in the development (C-statistic 0·87, 95 per cent c.i. 0·85 to 0·88) and validation (C-statistic 0·86, 0·84 to 0·87) groups. The most important co-variables in the final model were: age (OR 3·17-27·10), rectal (OR 31·48) or abdominal (OR 1·83-8·45) mass, iron deficiency anaemia (IDA) (OR 4·42-8·38), rectal bleeding and change in bowel habit in combination (OR 5·37), change in bowel habit without rectal bleeding, with or without abdominal pain (OR 2·12-2·52), and rectal bleeding with no perianal symptoms and without change in bowel habit (OR 2·91). Some 91·5 per cent of bowel cancers presented with these characteristics, 40·4 per cent with a mass and/or IDA. In patients with at least one of these characteristics the overall risk of having cancer was 10·0 (range 6·5-50·4) per cent, compared with 1·1 (0·3-2·3) per cent in patients without them.

CONCLUSION

A clinical assessment that systematically identifies or excludes four symptom-age combinations, a mass and IDA (SAMI) stratifies patients as having a low and higher risk of having bowel cancer. This could improve patient selection for referral and investigation.

Influence of complications following immediate breast reconstruction on breast cancer recurrence rates

BACKGROUND

The rate of immediate breast reconstruction is rising. Postoperative infections are more frequent in patients who undergo reconstruction. The inflammatory response to a postoperative infection can increase the risk of tumour recurrence in other forms of cancer through the release of proinflammatory mediators. The aim of this study was to assess the relationship between complications and breast cancer recurrence in patients undergoing immediate reconstruction.

METHODS

This was a review of a prospectively maintained database of all patients who had immediate breast reconstruction between 2004 and 2009 at Galway University Hospital, a tertiary breast cancer referral centre serving the west of Ireland. All patients had a minimum follow-up of 5 years. Outcomes assessed included the development of wound complications and breast cancer recurrence. The data were evaluated by univariable and multivariable Cox regression analysis.

RESULTS

A total of 229 patients who underwent immediate reconstruction were identified. The overall 5-year recurrence-free survival rate was 85·6 per cent. Fifty-three patients (23·1 per cent) had wound complications, of whom 44 (19·2 per cent) developed a wound infection. There was a significantly greater risk of developing systemic recurrence among patients who experienced a postoperative wound complication compared with those without a complication (hazard ratio 4·94, 95 per cent c.i. 2·72 to 8·95; P < 0·001). This remained significant after adjusting for Nottingham Prognostic Index group in the multivariable analysis. The 5-year recurrence-free survival rate for patients who had a wound complication was 64 per cent, compared with 89·2 per cent in patients without a complication (P < 0·001).

CONCLUSION

This study has demonstrated that wound complications after immediate breast reconstructive surgery have significant implications for patients with breast cancer. Strategies are required to minimize the risk of postoperative wound complications in patients with breast cancer undergoing immediate reconstruction.

Clinical and economic benefit of general practitioner integration to a symptomatic breast service

BACKGROUND

Integration of general practitioners (GPs) into a tertiary care team is a model used internationally to assist with provision of patient care. Symptomatic breast clinics have seen significant increases in attendances and consequential staffing issues. We wished to analyze the integration of GPs into a tertiary breast care team and establish whether their inclusion is a cost-effective approach.

METHODS

A prospectively maintained database was used to identify 1614 new and 1453 review patients seen in the clinic between September and December 2013. The triple assessment clinical, radiological, and biopsy scores of patients assessed by GPs were compared to those assessed by registrars and to the overall number of patients seen. A cost analysis was performed based on the hourly rates of GPs and registrars.

RESULTS

1614 new patients seen over the 4-month period. GPs reviewed a mean of 153.6 new patients and registrars reviewed a mean of 97.8. Registrars reviewed patients who were allocated higher 'S' scores, with 46 % of patients allocated an S4 and 21 % of patients allocated an S5 score. GPs reviewed a mean of 115.6 return patients and registrars reviewed a mean of 110.1 return patients. The weekly cost of employing 3 GPs for 15 h was €835. This compares favorably to the cost of employing a full-time registrar.

CONCLUSION

This study demonstrates that GPs can play a substantial role in the provision of a symptomatic breast service. In addition, the incorporation of GPs in this setting can prove cost-effective.

A meta-analysis to determine the oncological implications of conversion in laparoscopic colorectal cancer surgery

AIM

Laparoscopic colon and rectal cancer surgery is oncologically equivalent to open resection, but the impact of conversion is undetermined. The aim of this study was to assess the oncological outcome and predictive factors associated with conversion.

METHOD

A comprehensive search for published studies examining the associated factors and outcome of conversion from laparoscopic to open colorectal cancer resection was performed adhering to PRISMA (Preferred Reporting Items in Systematic Reviews and Meta-analyses) guidelines. Only randomized control trials and prospective studies were included. Each study was reviewed and the data extracted. Random effects methods were used to combine data.

RESULTS

Fifteen studies, including 5293 patients, met the inclusion criteria. Of these 4391 patients had a completed laparoscopic resection and 902 were converted to an open resection. The average conversion rate of the studies was 17.9 ± 10.1%. Meta-analysis showed completed laparoscopic surgery favoured lower 30-day mortality (OR 0.134, 95% CI 0.047-0.385, P < 0.0001), lower long-term disease recurrence (OR 0.634, 95% CI 0.421-0.701, P < 0.023) and lower overall mortality (OR 0.512, 95% CI 0.417-0.629, P < 0.0001). Factors negatively associated with completion of laparoscopic surgery were male gender (P = 0.011), rectal tumour (P = 0.017), T3/T4 tumour (P = 0.009) and node-positive disease (P = 0.009). Completed laparoscopic surgery was also associated with a lower body mass index (BMI; mean difference -0.93 kg/m(2) , P = 0.004).

CONCLUSION

The results suggest that conversion from laparoscopic to open colorectal cancer resection is influenced by patient and tumour characteristics and is associated with an adverse perioperative outcome. Although confounding factors such as advanced tumour stage and elevated BMI are present, unsuccessful laparoscopic surgery appears to be associated with an adverse long-term oncological outcome.

Dynamic evaluation of human vestibulo-ocular function using white noise rotation stimulus and linear system parameter estimation techniques

White noise acceleration inputs were used to determine the human VOR transfer function both for normal subjects and for patients falling into two pilot categories: unilateral labyrinthectomy and reduced bilateral responses. The systematic patterns shown in the transfer function of the pilot abnormal categories as compared to the normal data suggests one method of classifying test results (table I). Frequency domain linear systems parameter fits were also made using the same data. The changes in these fit parameters, when pilot abnormal data is compared to normal data, suggests the use of the parameter fits themselves as a second classification scheme (fig. 1). The second scheme is not appropriate in cases where the response is unrelated to the stimulus.

Emergency surgery pre-operative delays - realities and economic impacts

BACKGROUND

A key principle of acute surgical service provision is the establishment of a distinct patient flow process and an emergency theatre. Time-to-theatre (TTT) is a key performance indicator of theatre efficiency. The combined impacts of an aging population, increasing demands and complexity associated with centralisation of emergency and oncology services has placed pressure on emergency theatre access. We examined our institution's experience with running a designated emergency theatre for acute surgical patients.

METHODS

A retrospective review of an electronic prospectively maintained database was performed between 1/1/12 and 31/12/13. A cost analysis was conducted to assess the economic impact of delayed TTT, with every 24hr delay incurring the cost of an additional overnight bed. Delays and the economic effects were assessed only after the first 24 h as an in-patient had elapsed.

RESULTS

In total, 7041 procedures were performed. Overall mean TTT was 26 h, 2 min. There were significant differences between different age groups, with those aged under 16 year and over 65 having mean TTT at 6 h, 34 min (95% C.I. 0.51-2.15, p < 0.001) and 23 h, 41 min (95% C.I. 19.6-23.9, p < 0.001) respectively. 2421 (34%) waited greater than 24 h for emergency procedures. The >65 years age group had a mean TTT of 23 h, 41 min which was significantly longer than the overall mean TTT Vascular and urological emergencies are significantly disadvantaged in competition with other services for a shared emergency theatre. The economic impact of delayed TTT was calculated at €7,116,000, or €9880/day of additional costs generated from delayed TTT over a 24 month period.

CONCLUSION

One third of patients waited longer than 24 h for emergency surgery, with the elderly disproportionately represented in this group. Aside from the clinical risks of delayed and out of hours surgery, such practices incur significant additional costs. New strategies must be devised to ensure efficient access to emergency theatres, investment in such services is likely to be financially and clinically beneficial.

Less stress, more success? Oncological implications of surgery-induced oxidative stress

Reactive oxygen species (ROS) possess important cell signalling properties. This contradicts traditional thought which associated ROS activity with cell death. Emerging evidence clearly demonstrates that ROS signalling acts as a key regulator in tumour cell survival and in the cellular processes required for tumour cells to successfully metastasise and proliferate. The discovery of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) family of enzymes in the last decade has unravelled much of the mystery surrounding how ROS are generated. Tumour cells are now known to express Nox enzymes which produce ROS required for cellular signalling. Activation of Nox enzymes occurs via interaction with proinflammatory cytokines and growth factors, all of which are released following surgical trauma. As our understanding of the signalling capabilities of ROS grows, the oncological implications of ROS activity are gradually being revealed. Nox-derived ROS are known to play a central role in each step of the metastatic cascade including invasion, adhesion, angiogenesis and proliferation. This article describes how surgery creates a ROS-rich environment, which facilitates redox signalling, and also examines the role played by Nox enzymes in this process. The authors then explore current knowledge of the oncological implications of surgery-induced redox signalling, and discuss current and future therapeutic strategies targeted at ROS and Nox enzymes in cancer patients.

Preoperative estimation of tibial nail length--because size does matter

INTRODUCTION

Selecting the correct tibial nail length is essential for satisfactory outcomes. Nails that are inserted and are found to be of inappropriate length should be removed. Accurate preoperative nail estimation has the potential to reduce intra-operative errors, operative time and radiation exposure.

METHODS

We compared the most commonly used radiological, anthropometric and intra-operative techniques to determine ideal nail lengths for 16 paired cadaveric tibiae. Five different anthropometric measurements were taken from each intact cadaver including: knee joint line to ankle joint line distance (JJD), medial knee joint line to medial malleolus distance (MMD), tibial tuberosity to medial malleolus distance (TMD), olecranon to 5th metacarpal head distance (OMD) and body height (BHR). Each tibia also underwent antero-posterior (AP) and lateral scanograms. Computerised tomography was used to determine the ideal nail length for each tibia. Each anthropometric and radiological measurement was recorded by two orthopaedic surgeons independently. An expert tibial nail was then inserted after nail length estimation was performed using a guidewire technique and an intra-operative radiographic ruler.

RESULTS

The AP scanogram was found to be 100% accurate in selecting ideal nail length. The lateral scanogram was also found to be reasonably accurate but in 19% (3/16) of cases it led to a nail being too long. The intra-operative radiographic ruler was found to give a good indication of the ideal nail size, as did the guidewire technique, with only 6% (1/16) of cases producing an incorrect nail size. In general, the anatomical measurements gave a poor indication of ideal nail size compared with the other techniques. The following accuracies were noted: JJD 56%, MMD 50%, TMD 38%, BHR 13% and OMD 56%.

CONCLUSIONS

We found that radiological methods such as using an AP radiograph with known magnification and intra-operative radiographic ruler were able to predict nail length very accurately and we suggest that these measurements should be performed routinely. The guidewire technique was also effective but we recommend that it not be used in isolation as errors can occur. We found that anatomical measurements are not accurate for predicting tibial nail length.

Effects of abdominal fat distribution parameters on severity of acute pancreatitis

BACKGROUND

Obesity is a well-established risk factor for acute pancreatitis. Increased visceral fat has been shown to exacerbate the pro-inflammatory milieu experienced by patients. This study aimed to investigate the relationship between the severity of acute pancreatitis and abdominal fat distribution parameters measured on computed tomography (CT) scan.

METHODS

Consecutive patients admitted to Cork University Hospital with acute pancreatitis between January 2005 and December 2010 were evaluated for inclusion in the study. An open source image analysis software (Osirix, v 3.9) was used to calculate individual abdominal fat distribution parameters from CT scans by segmentation of abdominal tissues.

RESULTS

A total of 214 patients were admitted with pancreatitis between January 2005 and December 2010. Sixty-two of these patients underwent a CT scan and were thus eligible for inclusion. Visceral fat volume was the volumetric fat parameter that had the most significant association with severe acute pancreatitis (P = 0.003). There was a significant association between visceral fat volume and subsequent development of systemic complications of severe acute pancreatitis (P = 0.003). There was a strong association between mortality and visceral fat volume (P = 0.019). Multivariate regression analysis, adjusted for gender, did not identify any individual abdominal fat distribution index as an independent risk factor for severe acute pancreatitis.

CONCLUSIONS

Overall, estimation of abdominal fat distribution parameters from CT scans performed on patients with acute pancreatitis indicates a strong association between visceral fat, severe acute pancreatitis, and the subsequent development of systemic complications. These data suggest that visceral fat volume should be incorporated into future predictive scoring systems.

The selective use of splenic flexure mobilization is safe in both laparoscopic and open anterior resections

AIM

Splenic flexure mobilization (SFM) is standard practice in anterior resections. No previous studies have compared outcomes with and without SFM in laparoscopic and open colorectal cancer surgery. This study aimed to determine whether routine or selective SFM should be advised.

METHOD

Data were collected prospectively on all elective anterior resections for cancer in our unit between October 2006 and November 2009.

RESULTS

Of 263 resections, SFM data were recorded in 216; 138 were laparoscopic (32% with SFM, 3.6% converted) and 78 open (68% with SFM). Eighty-eight were low anterior resections (LARs) for mid-low rectal cancers, with 54 laparoscopic (50% with SFM) and 34 open (91% with SFM). Comparing laparoscopic with SFM to without, differences were found in the proportion of LARs (61%vs 29%, P<0.001), defunctioning ileostomy rates (75%vs 46%, P=0.001) and operative time (median 255 vs 185 min, P<0.001), with no differences in age, gender, body mass index, American Society of Anesthesiology score, preoperative treatment, length of stay, lymph node yield, conversion rate, mortality, anastomotic leakage, reoperation, readmission and R0 resection. No differences in outcomes were seen between laparoscopic LARs with and without SFM or between open resections with and without SFM.

CONCLUSION

Our results show no disadvantage in short-term clinical or oncological outcomes when SFM was avoided. Laparoscopic anterior resections with SFM take longer. A selective approach to SFM is safe during anterior resection (open or laparoscopic), including mid-low rectal cancers.

Low rates of local recurrence after surgical resection of rectal cancer suggest a selective policy for preoperative radiotherapy

AIM

Preoperative short-course radiotherapy (SCRT) is increasingly recommended to reduce local recurrence after surgery for rectal cancer. Its avoidance may be beneficial, however, if the risk of local recurrence is low. We report a single centre experience which suggests that selective rather than uniform use of SCRT may be the best approach.

METHOD

Analysis was carried out on a prospectively collected unselected series of 1606 patients with rectal cancer treated in one centre. Follow-up was 97% complete. SCRT was performed selectively and all patients had a mesorectal excision.

RESULTS

Among 940 patients undergoing a potentially curative major resection the operative mortality was 4.6%, the permanent stoma rate 23% and the crude 5-year survival 61%. The local recurrence rate after curative anterior resection was 2.9% and 7.7% after abdominoperineal excision. The overall local recurrence rate after a potentially curative major resection was 4.0%.

CONCLUSION

The routine use of preoperative radiotherapy for rectal cancer is probably not justified where local recurrence after curative rectal resection is uncommon.

Rapid on-site evaluation of axillary fine-needle aspiration cytology in breast cancer

BACKGROUND

Axillary ultrasonography (AUS) and fine-needle aspiration cytology (FNAC) can establish axillary lymph node status before surgery, although this technique is hampered by poor adequacy rates. To achieve consistently high rates of FNAC adequacy, rapid on-site evaluation (ROSE) of FNAC samples was introduced.

METHODS

This single-centre, retrospective observational study of patients with newly diagnosed breast cancer undergoing preoperative AUS and FNAC between February 2008 and November 2010 examined the effect of the introduction of ROSE.

RESULTS

A total of 381 patients were included. AUS revealed 152 axillae with suspicious radiological features. FNAC was positive for malignant cells in 75 (49·3 per cent) of 152 samples. Sentinel lymph node mapping was avoided in 75 patients, representing 19·7 per cent of the entire study population. Adequacy rates increased from 78 per cent to 96 per cent following the introduction of ROSE (P = 0·001). The overall sensitivity and specificity of AUS and FNAC was 80·6 and 100 per cent respectively. A lymph node diameter equal to or larger than 10 mm and extranodal extension were significantly associated with positive FNAC (P < 0·001 and P = 0·012 respectively). Maximum lymph node diameter of at least 10 mm was an independent predictor of positive FNAC (odds ratio 11·2, 95 per cent confidence interval 3·32 to 37·76; P < 0·001).

CONCLUSION

AUS with FNAC provided accurate preoperative staging of the axilla for metastatic breast disease and avoided unnecessary sentinel lymph node mapping. The introduction of ROSE ensured the efficiency of AUS and FNAC.

Flexible sigmoidoscopy and whole colonic imaging in the diagnosis of cancer in patients with colorectal symptoms

BACKGROUND

The aim was to identify the patients with colorectal symptoms most likely to benefit from whole colonic imaging (WCI) to diagnose colorectal cancer and those for whom flexible sigmoidoscopy (FS) may be initially sufficient.

METHODS

This prospective observational study (16 years) included 16 433 newly referred patients with symptoms or signs of colorectal cancer.

RESULTS

Colorectal cancer was diagnosed in 946 patients (diagnostic yield 5.8 per cent), 815 (86.2 per cent) in the rectum or sigmoid (distal) and 131 (13.8 per cent) in the proximal colon. Some 15 829 patients (96.3 per cent) presented with symptoms alone (without iron deficiency anaemia or abdominal mass). Of 787 cancers in these patients, 750 (95.3 per cent) were distal. The prevalence of proximal cancer above and below the age of 60 years was 0.4 per cent (33 of 8249) and 0.1 per cent (four of 7580) respectively. Of 16 256 patients having FS, 5665 (34.8 per cent) had WCI. Of the other 10 591, five subsequently presented with proximal cancers. FS missed ten (1.3 per cent) of 796 cancers.

CONCLUSION

Patients with iron deficiency anaemia or a mass require WCI. However, in patients with symptoms alone, FS detects 95 per cent of cancers, and the diagnostic yield of WCI after FS is very low. Alternative management strategies need to be developed to avoid unnecessary investigations in this low-risk group.

The Department of Health's "two week standard" for bowel cancer: is it working?

OBJECTIVE

To determine the effectiveness and efficiency of the Department of Health's new general practitioner referral guidelines for bowel cancer.

DESIGN

One year prospective audit.

SETTING

District general hospital serving a population of 550 000.

SUBJECTS

All patients with bowel cancer; all patients referred on the basis of the two week standard and to a routine colorectal surgical outpatient clinic.

MAIN OUTCOME MEASURES

Proportion of cancers referred on the basis of the two week standard and to other colorectal clinics; the proportion with the higher risk criteria and their diagnostic yields; stage of cancers diagnosed in outpatient clinics; and time to treatment.

RESULTS

A total of 249 cancers were diagnosed in the index year. Sixty five (26.1%) were referred to two week standard clinics, 40 (16.1%) to routine colorectal surgical outpatient clinics, 54 (22%) to other clinics, and 88 (35.3%) were emergencies. Thirteen patients per week were referred to the two week standard clinics and 85% (54/65) of cancers so referred were seen within two weeks. The diagnostic yield of cancer in the two week standard clinic was 9.4% (65/695) compared with 2.2% (40/1815) in the routine colorectal surgical outpatient clinic (p<0.0001). Eighty five per cent of patients with cancer referred to outpatients matched the guidelines for the two week standard clinics. Only 46% of this group were so referred. Overall, delay to treatment and Dukes' stage were not improved in patients diagnosed in the two week standard clinics.

CONCLUSIONS

Most patients with bowel cancer were not referred on the basis of the two week standard although most fulfilled the referral criteria, which had higher diagnostic yields. The two week standard clinics did not shorten the overall time to treatment or improve the stage of disease because the time lags before referral and after the outpatient appointment are the major causes of delay in the bowel cancer patient's journey.

Intra-operative injection of Patent Blue V dye to facilitate nodal staging in colorectal cancer

OBJECTIVES

Routine histopathology may understage colorectal cancer by failing to detect involved lymph nodes. This study examined the feasibility of dye staining those lymph nodes most likely to harbour metastases.

PATIENTS AND METHODS

Patent Blue V dye 2.5% was injected intra-operatively into left-sided colorectal carcinomas prior to resection in 19 patients.

RESULTS

Blue-stained nodes were found in 12/19 patients (63%). Examination of blue-stained nodes alone correctly identified overall nodal status in 11 (92%) of these 12 patients.

CONCLUSION

The technique needs to be refined further. Nonetheless, intra-operative lymph node staining using blue dye offers the prospect of improving the ease and accuracy of nodal staging in colorectal cancer.

Quality of life after low anterior resection with total mesorectal excision and temporary loop ileostomy for rectal carcinoma

BACKGROUND

Low anterior resection (LAR) with total mesorectal excision (TME) may be the optimal operation for carcinoma of the mid or lower rectum. Routine formation of a temporary defunctioning stoma has been recommended with TME. The impact of this strategy on health-related quality of life (HRQOL) has not been addressed.

METHODS

A prospective longitudinal study was conducted among 24 patients undergoing LAR with TME and loop ileostomy for rectal cancer. Clinical outcomes were documented. HRQOL was assessed using Short Form 36 (SF-36). Twenty-three patients undergoing high anterior resection (HAR) for rectosigmoid cancer were studied concurrently to determine the effects of major colorectal resection without a stoma.

RESULTS

Time to resume normal diet, length of stay in hospital and time to return to non-work activities were similar after HAR or LAR with TME and loop ileostomy. Twelve weeks after HAR SF-36 scores were stable or improved compared with preoperative levels. In contrast, 12 weeks after LAR + TME patients had a reduction in physical functioning scores on SF-36. SF-36 scores improved after ileostomy closure. Ileostomy closure increased total hospital stay and time off non-work activities.

CONCLUSION

LAR with TME and temporary loop ileostomy for rectal cancer results in a long total hospital stay and impairs aspects of HRQOL. Prompt stoma closure should be a priority in these patients.

Approximating the number of monomer-dimer coverings in periodic lattices

Our starting point is an algorithm of Kenyon, Randall, and Sinclair, which is built upon the ideas of Jerrum and Sinclair, giving an approximation to crucial parameters of the monomer-dimer covering problem in polynomial time. We make two key improvements to their algorithm: we greatly reduce the number of simulations that must be run by estimating good values of the generating function parameter, and we greatly reduce the number of steps that must be taken in each simulation by aggregating to a simulation with at most five states. The result is an algorithm that is computationally feasible for modestly sized meshes. We use our algorithm on two- and three-dimensional problems, computing approximations to the coefficients of the generating function and some limiting values.

Chromosome identification using hidden Markov models: comparison with neural networks, singular value decomposition, principal components analysis, and Fisher discriminant analysis

The analysis of G-banded chromosomes remains the most important tool available to the clinical cytogeneticist. The analysis is laborious when performed manually, and the utility of automated chromosome identification algorithms has been limited by the fact that classification accuracy of these methods seldom exceeds about 80% in routine practice. In this study, we use four new approaches to automated chromosome identification--singular value decomposition (SVD), principal components analysis (PCA), Fisher discriminant analysis (FDA), and hidden Markov models (HMM)--to classify three well-known chromosome data sets (Philadelphia, Edinburgh, and Copenhagen), comparing these approaches with the use of neural networks (NN). We show that the HMM is a particularly robust approach to identification that attains classification accuracies of up to 97% for normal chromosomes and retains classification accuracies of up to 95% when chromosome telomeres are truncated or small portions of the chromosome are inverted. This represents a substantial improvement of the classification accuracy for normal chromosomes, and a doubling in classification accuracy for truncated chromosomes and those with inversions, as compared with NN-based methods. HMMs thus appear to be a promising approach for the automated identification of both normal and abnormal G-banded chromosomes.

Use of the greater omentum in colorectal surgery

INTRODUCTION

Complications related to impaired healing remain a major challenge in colorectal surgery. This review examines the potentially protective role of the greater omentum in colorectal operations.

METHODS

Review of all reports concerning applications of the greater omentum in colorectal surgery identified through MEDLINE (1966-1997) and other sources.

RESULTS

Clinical case studies indicate that an interposition flap of omentum is beneficial in the management of complex rectal fistulas. Pelvic omentoplasty or an omental hammock appears to reduce the incidence of radiation enteropathy in patients receiving pelvic radiotherapy after rectal resection. However, recent research demonstrates that omental wrapping does not "protect" colonic or rectal anastomoses. Nor is there convincing evidence that pelvic omentoplasty promotes primary perineal healing after abdominoperineal resection for cancer, although it may reduce the incidence of perineal wound breakdown.

CONCLUSIONS

Previous assumptions concerning the omentum are now being rigorously investigated with the aim of defining its true value in colorectal applications. This must be encouraged, especially where use of the omentum increases the magnitude or duration of operations significantly.

Tube caecostomy to protect rectal anastomoses

BACKGROUND

Low rectal anastomoses are associated with a substantial risk of anastomotic leakage. Tube caecostomy offers a potentially simple method of anastomotic protection.

METHODS

Some 226 patients undergoing restorative rectal resection with on-table colonic lavage and tube caecostomy over an 11-year period were reviewed. Endpoints selected included clinical anastomotic leakage, requirement for a subsequent formal stoma and complications of tube caecostomy.

RESULTS

Overall, clinical anastomotic leakage occurred in 25 patients with a caecostomy (11.1 per cent). All leaks were noted among patients in whom caecostomy protection had been used after low anterior resection, giving a leak rate of 14.9 per cent (25 of 168) for this group of whom 17 (10.1 per cent) required reoperation and a formal stoma, and five (3.0 per cent) died. Complications of caecostomy or prolonged drainage after tube removal occurred in ten (4.4 per cent) and 15 (6.6 per cent) patients respectively. There were two cases of life-threatening invasive infection.

CONCLUSION

Tube caecostomy provides inadequate protection of rectal anastomoses; complications are common and may be life threatening.

Definitive repair of anovaginal fistula in Crohn's disease

Anovaginal fistula may be a very distressing complication of Crohn's disease. We review the definitive repair of such fistulas in ten patients. The objectives were to cure the fistula, maintain continence and avoid proctectomy. The fistula was low trans-sphincteric in five patients, high trans-sphincteric in three and suprasphincteric in two. Loop ileostomies were formed in nine patients. Overall, after 14 repair procedures 8/10 fistulas are healed. Seven remain healed at a mean of 38 months (range 10-66 months) after ileostomy closure (six) or repair without ileostomy (one). All of the patients are continent. Definitive repair is effective and worthwhile in selected patients with Crohn's anovaginal fistula.

Spectral analysis of low-frequency, active-head vestibulo-ocular reflex responses

Useful medical diagnostic information has been reported from low-frequency rotational testing of the horizontal vestibulo-ocular reflex (VOR) of patients with vestibular disorders. Servocontrolled rotating systems have been used as the only practical method to generate stimuli over lower VOR frequency response ranges, the decade from 0.01 to 0.1 Hz. Active head movements have been used for testing the human VOR at higher frequencies, exceeding 0.5 Hz. We examined whether active head movements could be used also to test the VORs of subjects over lower frequency ranges, extending to 0.02 Hz. We used a swept-frequency, active head movement protocol to generate a broad-band stimulus. Eye position was recorded with electro-oculography. Head velocity was recorded with a rotational sensor attached to a head band. Six individual test epochs from human subjects were concatenated to form complex, periodic waveforms of head and eye velocity, 75 seconds in duration. Broad-band cross-spectral signal processing methods were used to compute horizontal VOR system characteristics from these waveforms extending from 0.02 to 2 Hz. The low-frequency VOR data appeared to originate from amplitude modulation of high-frequency active movements, acting as carrier signals. Control experiments and processing of simulated data from a known system excluded the possibility of signal processing artifacts. Results from six healthy subjects showed low-frequency gains and phase values in ranges similar to those from published rotational chair studies of normal subjects. We conclude that it is feasible to test the human VOR over extended low-frequency ranges using active head movements because of amplitude modulation of the head and eye signals.

Does hospital mortality rate reflect quality of care on a surgical unit?

All deaths occurring in 1 year in the surgical unit of a district general hospital were analysed to determine to what extent crude mortality rates reflect the quality of care. There were 166 deaths, 70% of patients were aged 75 years and older, and 87.3% were emergency admissions. Almost one-half (46.4%) of the deaths were inevitable. This high proportion of inevitable deaths means that crude hospital mortality rates are a poor indicator of the quality of surgical care. Factors such as the nature of the catchment area served, the proportion of emergency versus elective admissions, the numbers of complex operations performed and the availability of convalescent or hospice facilities are a greater influence on surgical mortality rates than variations in the standard of surgical care. The use of crude hospital mortality rates to compare the quality of care given by surgical units should be discontinued as it is unreliable and misleading.

Management of varicose veins according to reason for presentation

Of 229 newly referred patients with varicose veins, untoward symptoms were the most frequent reason for presentation (38%). Cosmetic concerns were significantly more common in women than in men (33% vs 8%, P < 0.001). Sclerotherapy was offered to 20 patients (8.7%). Surgical operation was offered in 113 (49.3%), mostly for symptoms. No invasive treatment was indicated in 96 patients (42%), more than half of whom had presented because of inappropriate fears of deterioration or with symptoms unrelated to their veins. We advocate that careful evaluation of the reasons for presentation should be used as a guide to the efficient management of varicose veins.

Comparison of vestibular autorotation and caloric testing

The two most common stimuli of the vestibular system for diagnostic purposes are caloric and rotational head movements. Caloric stimulation, by delivering thermal energy to the lateral semicircular canal, is a well-studied method of vestibular testing, and its clinical usefulness has been established. Vestibular autorotation testing uses high-frequency (2 to 6 Hz), active head movements to stimulate the horizontal and vertical vestibulo-ocular reflex to produce measurable eye movements that can be used to calculate gain and phase. We compared the alternate bilateral bithermal caloric results with the vestibular autorotation test results obtained from 39 patients with peripheral vestibular disorders and from 10 patients with acoustic neuroma. In the peripheral disorder group, only 2 of 14 patients with equal caloric response (< 20% reduced vestibular response) had a normal vestibular autorotation test result. No patients with a reduced vestibular response greater than 21% had a normal vestibular autorotation test result. In the acoustic neuroma group, four patients had a normal reduced vestibular response, but all patients had an abnormal vestibular autorotation test result. We conclude that testing both the horizontal and vertical vestibulo-ocular reflexes in their physiologic frequency range with the vestibular autorotation test provides additional information that could be missed by conventional caloric testing. Therefore high-frequency rotational testing is a valuable addition to the vestibular test battery.

Parathyroidectomy for hyperparathyroidism associated with renal disease

Between 1969 and 1993, 123 patients were accepted in this unit for surgery for refractory hyperparathyroidism associated with chronic renal failure. Subtotal parathyroidectomy was the procedure of choice. At operation, four or more parathyroids were identified in 75% of patients. Methylene blue localised additional parathyroids in 32% of initial explorations in which it was used. Coincidental thyroid pathology was found in 8.3%, including papillary carcinoma in 2.4%. No further parathyroid surgery was required in 90% of patients at a mean of 6.6 years after operation. Reoperation (10%) was more likely to be required (14.3%) when less than four glands were found than when four or more were found (8.5%). Patients continuing on dialysis were more likely to need reoperation than those with functioning renal transplants.

Predictive monitoring of high-frequency vestibulo-ocular reflex rehabilitation following gentamicin ototoxicity

Nine patients exposed to gentamicin ototoxicity were tested with active head movements to determine their high-frequency (2-6 Hz) horizontal and vertical vestibulo-ocular reflex (VOR) responses. Results showed a common pattern documenting patients' reports of oscillopsia during walking: gains of 0.5 or less, and phases less than 180 degrees. A subset of these patients undergoing exercise rehabilitation therapy were tested repeatedly during follow-up visits to monitor changes in their VORs. VOR improvements toward reduced oscillopsia were correlated with patients' reported reduction of symptoms. Each patient's VOR changes over time were monitored with a quantitative least-squares method which predicted results of the next test, based on trends from three or more previous tests. The method was tested by comparing predicted results with actual test results, following the next test. Preliminary results show relatively accurate predictions up to 6 weeks in advance of actual tests, at least when trends of recent, previous tests were in a consistent direction. We conclude that predictive monitoring of changing VOR states can be useful for continuing, or modifying, the course of vestibular rehabilitation therapy, by providing quantitative prediction estimates of future results.

Analysis of a year's general surgical activity in a District General Hospital

The activity of the surgical unit of a District General Hospital was analysed over a one-year period. The numbers of outpatients seen, admissions, operations performed, and operative workload were all higher, in terms of the available surgical personnel, than those expected of a unit of this size. Thirty-five per cent of admissions were emergencies but these occupied 58 per cent of bed days. Nonetheless, three-quarters of admitted patients were discharged within five days. Three-quarters of operations were Minor or Intermediate, one-quarter were Major or more complex. Consultants performed/supervised 48 per cent of operations. 42.5 per cent were performed by unsupervised trainees and 9.4 per cent by clinical assistants. Solo trainees performed the majority of emergency operations (73.7 per cent). With regard to operative activity, the Service Equivalent Value of consultants and trainees approximated to expectations, but clinical assistants contributed more than expected.

Autorotation test abnormalities of the horizontal and vertical vestibulo-ocular reflexes in panic disorder

Patients with panic disorder often describe dizziness as a disturbing symptom, with more severe episodes reported than in other psychiatric populations. Nineteen patients diagnosed as having a panic disorder were tested for vestibulo-ocular (VOR) abnormalities with the Vestibular Autorotation Test (VAT), a computerized test of the high-frequency (2 to 6 Hz) VOR. The patients were unselected for the presence or absence of balance disorders. Results showed VOR abnormalities, relative to a normal population, in the horizontal and/or vertical VORs of all 19 patients. Vestibulo-ocular reflex asymmetries were commonly present. Because the VAT tested the VOR over a frequency range encountered during common daily activities, the observed abnormalities could result in a perceptually moving visual field (oscillopsia). We hypothesize that the resulting experience of a visual-vestibular disturbance--perhaps in a biologically or psychologically predisposed individual--is catastrophically misinterpreted, leading to more bodily symptoms and anxiety. These could then contribute to more misinterpretation in a positive feedback sense, ultimately leading to a panic attack.

Artificial bile inhibits bile salt-induced gallbladder glycoprotein release in vitro

The more hydrophobic bile salts cause rapid release of preformed gallbladder mucin and other glycoproteins by gallbladder explants in vitro, whereas the less hydrophobic bile salts elicit a lesser response. This study was designed to determine (a) whether this short-term effect was matched by a sustained increase in glycoprotein secretion over 24 hr and (b) whether it occurred when bile salts were presented in model biles rather than aqueous solution. Although 3 mmol/L taurodeoxycholate in aqueous solution increased release of preformed gallbladder glycoprotein to 843% of control values after 30 min incubation (p < 0.001), no significant increase was observed after 24 hr. The more prolonged exposure also reduced precursor uptake by 32% (p < 0.05) and inhibited synthesis of new glycoprotein by 24% (p < 0.05). Moreover, the stimulatory effect of taurodeoxycholate on release of gallbladder glycoprotein was much reduced when it was presented in model biles rather than in aqueous solution. Nor was there any difference between the effects of more hydrophobic vs. less hydrophobic bile salts when presented in model biles. Aqueous solutions of the more hydrophobic bile salts induce a rapid release of gallbladder glycoprotein in vitro but do not produce a sustained increase in glycoprotein secretion. Their effect is liable to be prevented in vivo by interaction between bile salts and the other lipids in gallbladder bile.

Increased dietary fat content accelerates cholesterol gallstone formation in the cholesterol-fed prairie dog

Epidemiological studies have provided conflicting information about the relationship between fat consumption and gallstone formation. We studied cholesterol gallstone formation in prairie dogs after 1 wk of the following diets: (group A) a control diet with no added cholesterol and 5% of calories from corn oil, (group B) 1.2% cholesterol with 5% of calories from corn oil or (group C) 1.2% cholesterol with 40% of calories from corn oil. In controls serum cholesterol was 58.9 +/- 4.5 mg/dl, gallbladder bile was unsaturated with cholesterol (cholesterol saturation index = 0.7 +/- 0.1; cholesterol = 3.8 mmol/L) and none of 12 animals formed cholesterol crystals or stones. The low-fat diet supplemented with cholesterol (group B) increased serum and biliary cholesterol concentrations to 292 +/- 76 mg/dl and 7.5 +/- 1.1 mmol/L, respectively (p < 0.05), but cholesterol saturation index was only modestly increased (1.1 +/- 0.1) and in only one of eight animals did cholesterol monohydrate crystals develop. Group C, animals, which received cholesterol plus high levels of corn oil, had higher serum cholesterol levels (457 +/- 66 mg/dl), higher biliary cholesterol concentrations (16.6 +/- 1.3 mmol/L), higher cholesterol saturation indexes (1.7 +/- 0.1) and increased incidence of cholesterol gallstones (5 of 11). The two cholesterol-supplemented diets increased biliary phospholipid concentrations, decreased the ratio of cholic/chenodeoxycholic acid and increased the proportion of biliary lecithins containing linoleic acid, but these abnormalities were greatest in group C, which was given large amounts of corn oil. These findings suggest that cholesterol gallstone formation in the prairie dog is accelerated by increased dietary omega-6 polyunsaturated triglycerides.

Autorotation test of the horizontal vestibulo-ocular reflex in Menière's disease

Sixty-four patients with the diagnosis of Menière's disease were tested at the House Ear Clinic with an active head-rotation test system, the Vestibular Autorotation Test (VAT). The VAT is a portable, computerized test that measures the horizontal vestibulo-ocular reflex (VOR) with the use of high-frequency (2 to 6 Hz) active head movements to obtain gain and phase. The purpose of this study was to characterize the horizontal VOR at high frequencies in patients with Menière's disease. At frequencies from 5 to 6 Hz, all patients demonstrated horizontal phase greater than 180 degrees and 85% showed abnormal VAT results. The most common patterns were decreased gain or increased phase values, or both, relative to normative data. No significant differences in the degree of abnormality in gain and phase were noted among groups of patients when the patients were clinically staged. We conclude that, in our test population of patients with Menière's disease, the VAT shows common gain and phase patterns and abnormalities of the horizontal VOR. This may contribute to high retinal image velocities, which render the patient unable to stabilize retinal images during locomotion (visual field image slip), in as many as 85% of the patients tested, regardless of clinical stage. Such high-frequency testing can reveal abnormalities of the horizontal VOR not apparent from conventional vestibular testing. Thus VAT provides additional information about the functioning VOR when combined with the present vestibular test battery.

Effects of sedation and supplemental oxygen during upper alimentary tract endoscopy

The effects of supplemental oxygen therapy on arterial oxygen saturation (SaO2) in unsedated and sedated patients have been studied using pulse oximetry. Hypoxia (minimum SaO2 92% or less) occurred in 41% of unsedated patients breathing room air but in only 11% (p < 0.01) of those receiving supplemental oxygen (41/min) by nasal cannulae. Comparable effects were seen in sedated patients (60% versus 16%, respectively, p < 0.01). Hypoxia during upper alimentary tract endoscopy is common with or without sedation and can be reduced by supplemental oxygen.