Validation of a sub-epidermal moisture scanner for early detection of pressure ulcers in an ex vivo porcine model of localized oedema.

Pressure ulcers (PUs) remain a chronic health problem with severe impacts on healthcare systems. Early detection is crucial to providing effective interventions. However, detecting PUs currently relies on subjective tissue evaluations, such as visual skin assessment, precluding interventions prior to the development of visible tissue damage. There is an unmet need for solutions that can detect early tissue damage before visual and tactile signs occur. Assessments based on sub-epidermal moisture (SEM) measurements represent an opportunity for robust and objective early detection of PUs, preventing broken skin PUs in more high-risk patients at high-risk anatomical locations. While SEM assessment technology has been validated in computational, bench and tissue phantom models, validation in soft tissue was absent. In this study, we successfully validated the ability of a commercially available SEM assessment device to measure and detect sub-epidermal moisture changes in a novel ex vivo porcine soft tissue model of localised oedema. When controlled and incremental fluid volumes (Phosphate Buffer Solution) were injected into porcine soft tissues, statistically significant differences were found in SEM values between fluid-injected sites, representing an inflammatory oedematous condition, and healthy tissue control sites, as measured by the SEM device. The device provided reproducible readings by detecting localised oedema changes in soft tissues, reflecting the build-up of fluid as small as 1 ml into the underlying tissue. Spatial characterization experiments described the ability of the device technology to differentiate between healthy and oedematous tissue. Our findings validate the use of SEM assessment technology to measure and quantify localized oedema.

Modelling the effects of age-related morphological and mechanical skin changes on the stimulation of tactile mechanoreceptors.

Our sense of fine touch deteriorates as we age, a phenomenon typically associated with neurological changes to the skin. However, geometric and material changes to the skin may also play an important role on tactile perception and have not been studied in detail. Here, a finite element model is utilised to assess the extent to which age-related structural changes to the skin influence the tactile stimuli experienced by the mechanoreceptors. A numerical, hyperelastic, four-layered skin model was developed to simulate sliding of the finger against a rigid surface. The strain, deviatoric stress and strain energy density were recorded at the sites of the Merkel and Meissner receptors, whilst parameters of the model were systematically varied to simulate age-related geometric and material skin changes. The simulations comprise changes in skin layer stiffness, flattening of the dermal-epidermal junction and thinning of the dermis. It was found that the stiffness of the skin layers has a substantial effect on the stimulus magnitudes recorded at mechanoreceptors. Additionally, reducing the thickness of the dermis has a substantial effect on the Merkel disc whilst the Meissner corpuscle is particularly affected by flattening of the dermal epidermal junction. In order to represent aged skin, a model comprising a combination of ageing manifestations revealed a decrease in stimulus magnitudes at both mechanoreceptor sites. The result from the combined model differed from the sum of effects of the individually tested ageing manifestations, indicating that the individual effects of ageing cannot be linearly superimposed. Each manifestation of ageing results in a decreased stimulation intensity at the Meissner Corpuscle site, suggesting that ageing reduces the proportion of stimuli meeting the receptor amplitude detection threshold. This model therefore offers an additional biomechanical explanation for tactile perceptive degradation amongst the elderly. Applications of the developed model are in the evaluation of cosmetics products aimed at mitigating the effects of ageing, e.g. through skin hydration and administration of antioxidants, as well as in the design of products with improved tactile sensation, e.g. through the optimisation of materials and surface textures.

Should laparoscopic lymph node biopsy be the preferred diagnostic modality for isolated abdominal lymphadenopathy?

Background: Isolated abdominal lymphadenopathy is frequently detected, but often challenging to diagnose. To obtain a tissue diagnosis, percutaneous biopsy (pb) or laparoscopic biopsy (lb) is often undertaken. The safety profiles and diagnostic accuracy of pb and lb within the abdomen are both poorly defined. Methods: In this retrospective analysis, we identified all patients who underwent lb or pb for isolated abdominal lymphadenopathy at our institute during 2008-2016. Results: Of 62 patients who underwent nodal biopsy for isolated abdominal lymphadenopathy, 33 underwent lb and 29 underwent pb. For the 33 patients who underwent lb, the procedure was diagnostic in 100% of cases; for the 29 who underwent pb, the procedure was diagnostic in 18 cases (62.1%). Both procedures were safe, with similar complication rates (6.0% for lb; 7.0% for pb). Conclusions: Our results establish that lb and pb are both safe and reliable in the setting of isolated abdominal lymphadenopathy. We also demonstrate that each procedure has situational advantages. A pb should be considered to be the upfront diagnostic modality, particularly when anatomic or disease factors favour its success. In situations in which it is felt that pb cannot safely access the lymphadenopathy or in disease states in which the yield of a core biopsy will be insufficient, lb should be strongly considered. Examples include extra-retroperitoneal lymphadenopathy and cases of suspected lymphoma.

The Effect of Bariatric Surgery on Urinary Incontinence in Women.

BACKGROUND: Little is known regarding the effect of bariatric surgery on urinary incontinence. METHODS: Between September 2008 and November 2014, 240 female patients underwent bariatric surgery. RESULTS: The prevalence of urinary incontinence preoperatively was 45 % (108). Eighty-two (76 %) completed urinary function questionnaires pre-operatively and post-operatively. Fifty-seven (70 %) underwent laparoscopic gastric bypass, twenty-four (29 %) underwent sleeve gastrectomy and one underwent a banding procedure. Thirty-one (38 %) reported leaking on sneezing or coughing-stress urinary incontinence (SUI). Thirteen (16 %) complained of leaking before reaching the toilet-overactive bladder syndrome (OAB). The remaining thirty-eight (46 %) reported mixed symptoms. The mean pre-operative weight and BMI were 133 (18) kg and 50 (SD = 6.2) kg/m(2) respectively. The mean post-operative BMI drop was 16 (SD = 5.2) kg/m(2). Preoperatively, 61 (75 %) reported moderate to very severe urinary incontinence compared to 30 (37 %) post-operatively (χ (2) = 3.24.67, p = 0.050). Twenty-seven (33 %) patients reported complete resolution of their urinary incontinence. Fifty-one (62 %) patients required incontinence pads on a daily basis pre-operatively, compared to 35 (43 %) post-operatively (χ (2) = 22.211.6, p = 0.00). The mean International Consultation on Incontinence Questionnaire- Urinary Incontinence short form (ICIQ-UI SF) score was 9.3 (SD = 4.4) pre-operatively compared to 4.9 (SD = 5.3) post-operatively (t = 7.2, p = 0.000). The improvement score post-operatively was 8 (SD = 3). A significant difference in the ICIQ-UI SF was identified between OAB and SUI groups when adjusting for age, number of children, type of delivery and pre-op BMI (t = 1.98, p = 0.05). CONCLUSION: Bariatric surgery results in a clinically significant improvement in urinary incontinence. However, this is not proportional to pre-operative BMI, weight loss, age, parity and mode of delivery.

Computational simulation methodologies for mechanobiological modelling: a cell-centred approach to neointima development in stents.

The design of medical devices could be very much improved if robust tools were available for computational simulation of tissue response to the presence of the implant. Such tools require algorithms to simulate the response of tissues to mechanical and chemical stimuli. Available methodologies include those based on the principle of mechanical homeostasis, those which use continuum models to simulate biological constituents, and the cell-centred approach, which models cells as autonomous agents. In the latter approach, cell behaviour is governed by rules based on the state of the local environment around the cell; and informed by experiment. Tissue growth and differentiation requires simulating many of these cells together. In this paper, the methodology and applications of cell-centred techniques--with particular application to mechanobiology--are reviewed, and a cell-centred model of tissue formation in the lumen of an artery in response to the deployment of a stent is presented. The method is capable of capturing some of the most important aspects of restenosis, including nonlinear lesion growth with time. The approach taken in this paper provides a framework for simulating restenosis; the next step will be to couple it with more patient-specific geometries and quantitative parameter data.

Laparoscopic fundoplication: a 10-year learning curve.

BACKGROUND: Laparoscopic Nissen fundoplication (LNF) has become the most common surgical treatment for gastroesophageal reflux disease (GERD). Controversies still exist regarding the operative technique and the durability of the procedure. METHODS: A retrospective study of 808 patients undergoing 838 LNF for GERD at a tertiary referral center was undertaken. Demographic, perioperative, and follow-up data had been entered onto the unit database. RESULTS: During a median follow-up period of 60 months (range, 2-120 months), heartburn decreased to 3% of the patients (19/645) and regurgitation to 2% (11/582) (p < 0.01). Respiratory symptoms improved in 69 (85%) of 81 patients (p < 0.01). The incidence of postoperative dysphagia was unaffected by the use of an intraesophageal bougie (odds ratio [OR], 1.16; 95% confidence interval [CI], 0.82-1.64; p = 0.41) or division of the short gastric vessels (OR, 0.84; 95% CI, 0.42-1.07; p = 0.72). In the immediate postoperative period, the incidence of abdominal symptoms increased by 10% (p < 0.01) and dysphagia by 16% (p < 0.01). After 10 postoperative years, only 3% (30/484) were found to have abdominal symptoms, whereas the incidence of dysphagia declined to zero. CONCLUSION: The findings show that LNF is a safe and effective procedure with long-term durability. Abdominal symptoms and dysphagia are the principal postoperative complaints, which improve with time. Personal preference should dictate the use of a bougie, division of the short gastric vessels, or both.

Day case laparoscopic herniorraphy. A NICE procedure with a long learning curve.

BACKGROUND: The aim of this study was to evaluate day case laparoscopic herniorraphy (LH) and to ascertain the impact of trainee surgeons on its performance. METHODS: We performed a prospective study of ambulatory laparoscopic transabdominal preperitoneal herniorraphies performed in a dedicated day surgical unit between March 1996 and October 2003. RESULTS: A total of 840 herniorraphies were performed in 706 consecutive patients. Surgery was performed by 15 higher surgical trainees and three consultant surgeons. The mean operating times for trainees were longer for unilateral (48.4 +/- 0.98 vs 41.4 +/- 0.87 min, p < 0.05) and bilateral (69.0 +/- 3.24 vs 53.0 +/- 1.68 min, p < 0.05) repairs than for consultants. Subgroup analysis demonstrated that after an experience of 40 procedures, trainee times approached those of the consultants (41.39 +/- 1.17 vs 41.4 +/- 0.87 min, p= 0.31). LH repair was well tolerated and associated with minimal postoperative pain and nausea. Mean pain scores postoperatively and at 24 h were 2.69 +/- 0.11 and 2.07 +/- 0.09, respectively. Mean nausea scores postoperatively and at 24 h were 0.34 +/- 0.06 and 0.22 +/- 0.06, respectively. Ninety-three percent of patients (n = 657) were discharged within 8 h. There were two conversions to an open procedure (0.1%) and two significant complications (0.1%). Ninety-five percent of patients who responded to our questionnaire (n = 398/419) were satisfied with surgery and would undergo day case laparoscopic herniorraphy again. CONCLUSIONS: Laparoscopic herniorraphy is a safe technique suitable for day case surgery. Operator experience dictates duration of surgery. Trainees' operating times approach those of consultants after 40 procedures. Prolonged operating times and increased cost are not justifiable reasons for not recommending LH.

A prospective study of ambulatory laparoscopic cholecystectomy: training economic, and patient benefits.

BACKGROUND: Even though ambulatory laparoscopic cholecystectomy (ALC) is safe and cost effective, this approach has yet to gain acceptance in the United Kingdom. We report our 5-year experience of ALC with emphasis on its appropriateness for higher surgical training. METHODS: Between July 1997 and July 2002, patients with symptomatic cholelithiasis who met with appropriate criteria underwent ALC. Surgery was performed either by a consultant surgeon or a higher surgical trainee (HST) under direct supervision in our dedicated day surgery unit. Data were recorded prospectively and patients were interviewed postoperatively by an independent researcher. RESULTS: There were 269 patients (231 female and 38 male) with a median age of 46 years (range 17-76). Conversion to open cholecystectomy was necessary in three cases (1%). Of the patients, 79% (213) were discharged within 8 hours of surgery; 95% (256) were discharged on the same day. Thirteen patients (5%) required overnight admission as inpatients. An HST performed 166 (62%) of the procedures. There was a statistically significant difference in operating time between consultants (41 min) and trainees (47 min, P = 0.001) but no significant difference in clinical outcome or patient satisfaction. The mean procedural cost to the hospital was 768 pound sterling for ALC compared with 1430 pound sterling for an inpatient operation. Of patients, 87% expressed satisfaction with the day case operation. CONCLUSION: Our results for ALC compare favorably with published series. In addition, we have demonstrated that the operation can be performed safely by HST under direct supervision without compromising operating lists or safety.

Laparoscopic transperitoneal adrenalectomy.

BACKGROUND: From November 1993 to May 2002 a total of 172 laparoscopic adrenalectomies were attempted in 152 patients in centers throughout the United Kingdom. RESULTS: The median age was 52 years (18-77 years). Sixty-three percent were female. Indications for resection were Conn's syndrome (60), pheochromocytoma (35), Cushing's disease (24), Cushing's adenoma (8), cortisol-secreting carcinoma (1), other secreting tumor (2), nonfunctioning adenoma (17), congenital adrenal hyperplasia (4), metastatic disease (7), nonsecreting adrenal carcinoma (2), others (12). Median size of the lesions was 3.0 cm (0.5-20 cm). Median operating time was 65 min (30-170 min). Conversion to an open procedure was necessary in 10 patients (7%). Minor morbidity occurred in nine patients (5%). Major morbidity occurred in two patients (pancreatitis, peritonitis). Median hospital stay was 3 days (1-16 days). At median follow-up of 36 months (1-105 months) five patients (4%) had persistent hypertension. No patient had evidence of recurrent hormonal excess. CONCLUSIONS: Laparoscopic removal of the adrenal gland should be considered the surgical procedure of choice in experienced minimally invasive centers.

Laparoscopic adjustable gastric banding: surgical and radiological approach.

BACKGROUND: The laparoscopically-placed adjustable gastric band (LAGB) is a minimally invasive, adjustable and completely reversible operation. We report 3 years experience. METHODS: Between May 1998 and January 2001, we operated on a consecutive series of 50 patients (8 male/42 female). Mean age of patients was 37 years (30-48). Mean preoperative BMI was 43 kg/m2 (range 38-55). RESULTS: Mean operative time was 130 minutes (range 75-150), and the conversion rate was 6%. Mean hospital stay was 2.8 days (range 2-10). Postoperatively 7/50 (14%) of patients had dysphagia and subsequently 2 (4%) developed gastric pouch dilatation. 2/50 (4%) had non-fatal pulmonary embolism and 2/50 (4%) developed gastroesophageal reflux. Overall morbidity was 32%. There has been no mortality. 6 weeks postoperatively, patients had adjustment of the band by the radiologists. Follow-up has been up to 30 months. Mean excess weight loss at 6 months was 30% (range 26-35%, N = 50), at 12 months 52% (range 44-55%, N = 42), at 24 months 60% (range 55-65%, N = 14) and at 30 months 62% (range 58-64%, N = 8). 5 patients have reached their ideal body weight. CONCLUSIONS: LAGB is safe and effective, even early in the learning curve. The radiologist plays a distinct role. A multi-disciplinary team approach is essential for optimal results. Long-term results are pending.

Helium vs carbon dioxide gas insufflation with or without saline lavage during laparoscopy.

BACKGROUND: Helium is an inert gas that, if used for insufflation during laparoscopy, may be followed by less postoperative pain than carbon dioxide (CO2) insufflation, due to a more limited effect on intraabdominal pH and metabolism. Saline lavage has also recently been shown to reduce postoperative pain following laparoscopic surgery. To evaluate these possibilities and to better define the clinical safety of helium insufflation, we undertook a prospective randomized trial comparing CO2 and helium insufflation with or without saline lavage in patients undergoing elective laparoscopic upper abdominal surgery. METHODS: From January to November 2000, 173 patients undergoing elective laparoscopic cholecystectomy or fundoplication were randomized to undergo laparoscopy with either CO2 or helium insufflation. Within each group, patients were further randomized to undergo peritoneal lavage with 2 L of 0.9% saline at the end of the surgical procedure. This yielded the following four patient groups; CO2 (group 1, n = 47), CO2 + saline lavage (group 2, n = 43), helium (group 3, n = 43) and helium + saline lavage (group 4, n = 40). Patients were blinded to their randomization, and post-operative assessment was also performed by a blinded investigator, who applied a standardized scoring system to assess postoperative pain. RESULTS: The study groups were well matched for age, sex, weight, American Society of Anesthesiologists (ASA) status, duration of surgery, and volume of gas utilized, and 81% of patients were discharged within 48 h. There were no differences in the incidence of postoperative complications among the study groups, and postoperative pain scores were not significantly different when all four groups were compared. When helium (groups 3 and 4) was compared with CO2 (groups 1 and 2), no differences in pain score were seen. When no lavage (groups 1 and 3) was compared with lavage (groups 2 and 4), less pain was found in the group undergoing saline peritoneal lavage (mean 4-h pain score, 5.9 vs 5.2; 24-h pain score, 4.8 vs 4.1; p > 0.05). CONCLUSIONS: The use of helium insufflation for laparoscopic surgery, while not associated with any significant adverse sequelae, was not associated with less postoperative pain in this trial. The use of saline peritoneal lavage was associated with less pain in the early postoperative period.

Obesity and its effect on outcome of laparoscopic Nissen fundoplication.

Obesity has long been suspected as predisposing to gastroesophageal reflux disease, and it has also been claimed that it is an important cause of poor outcome following laparoscopic anti-reflux surgery. This study was performed to determine the validity of this proposition. The outcome of 194 patients from an overall experience of 971 laparoscopic anti-reflux procedures was determined in this study. Patients were included if they had undergone a laparoscopic Nissen fundoplication, had completed a minimum 12 months follow-up using a structured questionnaire, and had data available for the calculation of their preoperative body mass index (BMI). Patients were divided into three groups based on BMI: normal weight (BMI < 25), overweight (BMI 25-29.9), and obese (BMI >30). The association between BMI and outcome data from their most recent follow-up was analyzed. There was no correlation between increasing BMI and a poorer overall outcome. There was a slight trend toward less satisfaction with the surgical outcome in patients of normal weight. Preoperative obesity is not associated with a poorer outcome following laparoscopic Nissen fundoplication.

Reflux disease without mucosal damage: is there a place for surgery?

Patients in whom regurgitation is a major problem usually require antireflux surgery even though they may have no evidence of esophageal mucosal damage. The most common symptom of reflux is heartburn, and there is good evidence that the severity of this symptom does not correlate with the degree of mucosal damage in the esophagus. With the advent of laparoscopic surgery and the great reduction in the morbidity of antireflux surgery, many patients now are looking for cure of their reflux rather than just symptom relief. Patients in this category do well with laparoscopic antireflux surgery regardless of whether thee have endoscopic evidence of mucosal damage or not; indeed, if the data in the literature are a guide, it seems that esophageal mucosal damage is not a necessary indication for antireflux surgery. An "acid-sensitive esophagus" is not yet an established indication for laparoscopic antireflux surgery, however.

Iatrogenic thoracic migration of the stomach complicating laparoscopic nissen fundoplication.

BACKGROUND: Intrathoracic gastric herniation after laparoscopic Nissen fundoplication is an uncommon but potentially life-threatening complication that may present in the early or late postoperative period. METHODS: A retrospective analysis was performed on all patients undergoing antireflux surgery from December 1991 to June 1999. RESULTS: Nine cases of gastric herniation occurred after 511 operations (0.17%). Patients presented with the condition 4 days to 29 months after surgery. Eight of these nine patients (89%) had reported vomiting in the immediate postoperative period. Seven patients (78%) reported persistent odynophagia. A factor common to all patients was that posterior crural repair had not been performed. CONCLUSIONS: Measures should be undertaken to prevent postoperative vomiting after laparoscopic Nissen fundoplication. Posterior crural repair is essential after surgery in all cases.

Primary small intestinal tumours: increased incidence of lymphoma and improved survival.

Small intestinal malignancies are rare and may have a delayed presentation owing to insidious growth. We have reviewed the case notes of 25 patients presenting with primary small bowel tumours over a 10-year period. Abdominal pain, weight loss and vomiting were the most common symptoms. The median duration of symptoms was 6 months. Physical examination was normal in 24% of patients. An abdominal mass was present in 46% of cases. Emergency laparotomy was undertaken in 28% of patients. Lymphomas were identified in 72% and adenocarcinomas were present in 16%. The predominance of small bowel lymphoma is an unusual finding and may be related to the high incidence of coeliac disease in the region. The median survival in the lymphoma group was 36 months, which compares favourably with reported series.

Alterations in intestinal barrier function do not predispose to translocation of enteric bacteria in gastroenterologic patients.

Bacterial translocation from the intestinal lumen has been demonstrated in humans. Three mechanisms have been suggested to explain the phenomenon: altered intestinal barrier function, bacterial overgrowth, and impaired host defense. The aim of this study was to determine whether changes in intestinal barrier function assessed by measurement of intestinal permeability and morphology were associated with alteration in bacterial translocation. Intestinal permeability was assessed in 43 patients by the lactulose/L-rhamnose test with a 5-h urine collection. Mucosal atrophy was assessed from the villus height-to-mucosal thickness ratio in small-bowel biopsies. Bacterial translocation was determined by microbiologic analysis of harvested mesenteric lymph nodes. No significant differences were apparent in the incidence of bacterial translocation in patients with normal permeability (5 [23%] of 22 patients translocated) compared with patients with increased permeability (4 [19%] of 21 patients translocated). Similarly, no correlation was apparent between the incidence of bacterial translocation and the index of villus atrophy. The degree of villus atrophy failed to correlate with gastrointestinal permeability. These data suggest that the incidence of bacterial translocation is not related to increased intestinal permeability or mucosal atrophy.