A circular inclusion with inhomogeneous non-slip imperfect interface in harmonic materials.

In this work, a rigorous study is presented for the problem associated with a circular inclusion embedded in an infinite matrix in finite plane elastostatics where both the inclusion and matrix are comprised a harmonic material. The inclusion/matrix boundary is treated as a circumferentially inhomogeneous imperfect interface that is described by a linear spring-type imperfect interface model where in the tangential direction, the interface parameter is infinite in magnitude and in the normal direction, the interface parameter is finite in magnitude (the so-called non-slip interface condition). Through the repeated use of the technique of analytic continuation, the boundary value problem for four analytic functions is reduced to solve a single first-order linear ordinary differential equation with variable coefficients for a single analytic function defined within the inclusion. The unknown coefficients of said function are then found via various analyticity requirements. The method is illustrated, using a specific example of a particular class of inhomogeneous non-slip imperfect interface. The results from these calculations are then contrasted with the results from the homogeneous imperfect interface. These comparisons indicate that the circumferential variation of interface damage has a pronounced effect on the average boundary stress.

Laparoscopic Rectopexy for Rectal Prolapse: Will it be the Gold Standard?

A review of the current literature is presented regarding the surgical management of full thickness rectal prolapse, comparing laparoscopic rectopexy with open abdominal operations and perineal procedures. Outcome measures include length of stay, short- and long-term outcomes and financial burdens. Current evidence suggests that laparoscopic rectopexy as treatment for full thickness rectal prolapse is a safe alternative to the other options.

Surgical resection of recurrent colonic cancer.

BACKGROUND: Locoregional recurrence of colonic cancer includes anastomotic recurrence, associated nodal masses, masses that involve the abdominal wall and pelvic masses. The aim of this study was to report the outcome of resection of such recurrences and to provide guidance on the management of this disease. METHODS: Patients were identified from a prospectively maintained database. Data were obtained on demographics, surgical procedure, morbidity, histopathology and outcome. Univariable and multivariable analyses of factors influencing survival were performed using stepwise Cox logistic regression. RESULTS: Forty-two patients (21 men; median age 61 (range 41-82) years) underwent resection of recurrent colonic cancer between 2003 and 2011. The median interval between resection of the primary and recurrent colonic tumour was 37·5 (interquartile range 7-91) months. The recurrences developed at the previous anastomosis (9 patients), elsewhere within the abdominal cavity or wall (8) and as discrete masses within the pelvic cavity (25). Eighteen of 42 patients underwent resection of hepatic or pulmonary metastases at some stage after resection of the primary tumour. Median survival was 29 months after R0 resection and 26 months after R1 resection of the recurrent tumour (P = 0·226). The survival benefit depended on the location of the recurrence (median survival after resection of recurrent disease: anastomotic 33 months, pelvic 26 months, abdominal 19 months; P = 0·010). CONCLUSION: This study described a classification system, management algorithm and prognostic factors for recurrent colonic cancer. The distribution of disease influenced survival. Long-term survival was achieved, including a subset of patients with drop metastases and/or previous metastasectomy.

Surgery for recurrent rectal cancer: higher and wider?

AIM: There has been a steady increase in the number of centres that carry out resection of locally recurrent rectal cancer (LRRC). The aim of this review was to highlight the present management and suggest technical strategies that may improve survival and quality of life. METHOD: The review identified relevant studies from an electronic search of MEDLINE and PubMed databases between 1980 and 2011. References in published articles were also reviewed. RESULTS: Surgical intervention offers the best hope to control LRRC but the proportion of patients offered this remains small. Certain contraindications previously considered to be absolute should now be thought of as relative. CONCLUSION: Awareness of the surgical options and a willingness to consider more aggressive options may result in more patients being considered for potentially curative resection.

Outcome of surgical resection of second-time locally recurrent rectal cancer.

BACKGROUND: Locally recurrent rectal cancer relapses in the pelvis in up to 60 per cent of patients following resection. This study assessed the surgical and oncological outcomes of patients who underwent surgery for re-recurrent rectal cancer. METHODS: Patients who underwent second-time resection of locally recurrent rectal cancer between 2001 and 2010 were eligible for inclusion. Data were collected on demographics, presentation of disease, preoperative staging imaging, adjuvant therapy, operative detail, histopathology and follow-up status (clinical and imaging) for the primary tumour, and first and second recurrences. RESULTS: Thirty patients (of 56 discussed at the multidisciplinary meeting) underwent resection of re-recurrent rectal cancer. Postoperative morbidity occurred in nine patients but none died within 30 days. Negative resection margins (R0) were achieved in ten patients, microscopic margin positivity (R1) was evident in 15 and macroscopic involvement (R2) was found in five. Although no patient had distant metastatic disease, 22 had involvement of the pelvic side wall. One- and 3-year overall survival rates were 77 and 27 per cent respectively, with a median overall survival of 23 (range 3-78) months. An R0 resection conferred a survival benefit (median survival 32 (11-78) months versus 19 (6-33) months after R1 and 7 (3-10) months after R2 resection). CONCLUSION: Surgical resection of re-recurrent rectal cancer had comparable surgical and oncological outcomes to initial recurrences in well selected patients.

Current UK management of locally recurrent rectal cancer.

AIM: The study aimed to determine current UK practice in the management of locally recurrent rectal cancer (LRRC). METHOD: An electronic based survey was sent to UK based Association of Coloproctology of Great Britain and Ireland members to establish current management in this patient group. A total of 188 questionnaires were sent out to consultant surgeons in a total of 105 colorectal units. RESULTS: Seventy-nine consultants from 69 units responded, giving an overall response rate from consultants of 42% and from colorectal units of 66%. In all, 688 patients were managed by multidisciplinary teams in the 12 months prior to the survey. Seventy-four (94% of responders) surgeons had experience of operating on patients with LRRC. Fifty-nine (74.6%) operated on one to three per year and four (5%) operated on more than 10 patients per year. Central and anterior recurrences were most commonly undertaken locally, with most complex recurrences being referred to a tertiary centre. Forty-seven (61%) surgeons worked to an algorithm. CONCLUSION: A small number of specialist units in the UK manage the full spectrum of LRRC but the majority of patients are managed in small volume centres. The survey provides a snapshot of current activity in the UK and may provide a stimulus for discussion about how to expand and improve the care of a technically challenging group of patients.

Laparoscopic fellowship training can deliver a competent laparoscopic surgeon and trainer.

AIM: The study investigated whether experience gained during a UK laparoscopic colorectal fellowship enabled the fellow subsequently to train consultant colleagues in laparoscopic surgery. METHOD: In one unit a newly appointed post-laparoscopic fellowship consultant (PFC) mentored his other two colleagues. Prospectively collected data regarding surgical outcome were compared with those of the year preceding the PFC appointment. RESULTS: In the preceding year 18.5% of 260 resections were attempted laparoscopically. This increased to 92.6% (of 270) in the year after (P < 0.0001). Respective conversion rates were 4.2% and 8.4% (P = 0.5524). In the first 6 months after PFC appointment, mentored consultants performed 23 supervised cases. In the second 6 months they carried out 58 procedures independently and trainees performed 38 supervised cases. There was no significant difference in anastomotic leakage and readmission and 30-day mortality rates between the pre- and post-PFC periods. CONCLUSION: A laparoscopic fellowship enables the PFC to mentor consultant colleagues safely and effectively.

Long-term efficacy of the button fistula plug in the treatment of Ileal pouch-vaginal and Crohn's-related rectovaginal fistulas.

BACKGROUND: Several new techniques have been described for the management of anal fistulas. The anal fistula plug has received much attention. The button plug adaptation has been heralded for use in rectovaginal and ileal pouch-vaginal fistulas. OBJECTIVE: The aim of this study was to report the long-term efficacy of the button plug in patients with such fistulas. DESIGN: All women with ileal pouch-vaginal and rectovaginal fistulas secondary to Crohn's disease who underwent insertion of a novel button fistula plug between May 2008 and November 2009 were prospectively evaluated. RESULTS: At long-term follow up of a median of 118 (interquartile range, 81.5-129.0) weeks, none of the 11 patients (0%) with ileal pouch-vaginal fistulas were considered to have healed, whereas 4 of the 9 patients (44%) with rectovaginal fistulas had healed. Each of these 4 patients whose treatment was successful were nonsmokers with an etiology of Crohn's disease and achieved complete closure of the fistula tract after one procedure, and none had been defunctioned. All repeat procedures failed. CONCLUSION: The button fistula plug may be an option for patients with Crohn's-related rectovaginal fistulas, albeit with the caveat of advising patients of a less than 50% success rate, but not for patients with ileal pouch-vaginal fistulas. Repeat attempts cannot be justified.

CT colonography for synchronous colorectal lesions in patients with colorectal cancer: initial experience.

AIM: To assess accuracy of CT colonography (CTC) in identifying synchronous lesions in patients with colorectal carcinoma. METHODS: This study included 174 consecutive patients undergoing CTC as part of staging or primary investigation where a colorectal cancer was diagnosed between 2004 and 2007. Prone unenhanced and portal phase enhanced supine series with air or CO(2) distension were acquired using 4- or 16-slice CT (Toshiba) and read by 2D +/- 3D formats. Synchronous lesions were classified according to American College of Radiology's (ACR) polyp classification. Segmental gold standard was flexible sigmoidoscopy/colonoscopy within 1 year and/or histology of colonic resection supplemented by follow-up. Nine patients without gold standard were excluded. Sensitivity, specificity and accuracy were calculated on a per polyp, per patient and per segment basis and discrepancies analysed. RESULTS: Direct comparable data were available for 764/990 colonic segments from 165 patients. Of 41 (C2-C4) synchronous lesions on "gold standard", 33 were correctly identified on virtual colonoscopy (VC), overall per polyp sensitivity was 80.5%, with detection rates of 20/24 C3 (83.3%) and 3/3 C4 (100%) with per patient and per segment specificity of 95.4% and 99.2%, respectively. CONCLUSION: CTC is an accurate technique to assess for significant synchronous lesions in patients with colorectal cancer and is applicable for total pre-operative colonic visualisation.

COX-2 expression is unexpectedly high in viable colorectal mucosal cells: is there life for chemoprophylaxis after VICTOR?

INTRODUCTION: Trials investigating colorectal cancer (CRC) chemoprophylaxis with cyclooxygenase-2 (COX-2) inhibitors have been discontinued because of adverse cardiovascular effects. Nevertheless, identification of patients where beneficial, chemo-prophylactic effects of COX-2 inhibitors outweigh side-effects may be possible; this study aimed to investigate whether such patient groups might exist. METHOD: The COX-2 status of viable epithelial and inflammatory cells in freshly disaggregated CRC and paired normal colonic samples was assessed by three-colour flow cytometry. RESULTS: 21/31 (67.7%) CRCs expressed COX-2, with inflammatory cells positive in 19/31 (61.3%), epithelial cells in 12/31 (38.7%), and both positive in 10/31 (32.3%). 25/30 (83.33%) normal samples expressed COX-2, with epithelial cells positive in 18/30 (60%), inflammatory cells in 15/30 (50%) and both positive in 10/30 (33.3%). Strength of expression by CRC and normal was similar. More advanced cancers had higher expression rates (COX-2 in 12/13 (92.3%) with nodal disease vs 9/17 (52.9%) node-negative; P = 0.04). CONCLUSION: Investigation of ex-vivo CRC cells by flow cytometry demonstrated COX-2 expression rates comparable to that previously reported. However, expression by paired live normal colon was significantly greater, suggesting that COX-2 may be expressed at higher rates in normal colonic cells in patients with CRC. Patients identified at resection as expressing COX-2 in normal colon may benefit from Coxib chemo-prophylaxis, thus potentially offering a refined approach to that adopted in the VICTOR trial.

The trial-packed, heat-processed spare complete denture.

A method has been described to make a second set of complete dentures for a patient. The second set of dentures will reflect relined tissue contours, use of manufactured artificial teeth, and trial-packed, heat-processed denture bases. The new dentures are of equal quality to the original dentures.

Determination of approximate size of maxillary anterior denture teeth when mandibular anterior teeth are present. Part III: Relationship of maxillary to mandibular central incisor widths.

The average width of a natural maxillary central incisor is 8.92 mm. This value is determined from the results of three studies of natural dentitions. The average width of a mandibular central incisor is 5.5 mm. The average ratio produced by dividing the average maxillary central incisor width by the average mandibular incisor width is 1.62. The factor of 1.5 times the width of a mandibular central incisor produces a maxillary central incisor width that is too narrow. The width of a mandibular central incisor plus half the width of the mandibular lateral incisor also produces a maxillary central incisor width that is too narrow. There may be a tendency to undersize the maxillary prosthetic dentition. The ratio of 1.62 can be used to select the appropriate width for a missing maxillary central incisor when given the width of the mandibular central incisor. This ratio of 1.62 is also valuable to verify the dimension of a selected artificial maxillary central incisor when the patient complains that the tooth is too large. If substitutions or adjustments are made in the mold, the desired canine-to-canine measurement produced by the ratio range of 1.3 to 1.38 reported in Parts I and II of this study should be maintained.

Determining approximate size of maxillary anterior artificial teeth when mandibular anterior teeth are present. Part I: Size relationship.

Three methods were used to obtain a ratio of the maxillary to the mandibular anterior teeth, with results of 1.29, 1.30, and 1.31. It can be concluded that a ratio of 1.30 is sufficient to determine the approximate width of the six maxillary anterior teeth when given the size of the mandibular natural anterior teeth. This ratio should be valid to select a maxillary denture mold of sufficient width mesiodistally to obtain a Class I canine relationship. However, the ratio may need a slight adjustment to compensate for the intentional disocclusion of the maxillary denture teeth with the natural mandibular teeth. In Fig. 1 the canine to canine measurement of the mandibular anterior teeth was 35 mm; when multiplied by a factor of 1.30, a maxillary measurement of 45.5 mm is obtained. The denture teeth were to be set with approximately 1 mm of horizontal overjet and 1 mm of vertical overlap (Fig. 2), therefore a slightly larger mold of 48.5 mm was chosen (Fig. 3). This maxillary mold produced a Class I canine relationship (Fig. 4). The 48.5 mm ratio of the chosen maxillary mold to the mandibular measurement of 35 mm yielded a ratio of 1.38. When this ratio of 1.38 is applied, the desired prosthetic mold is not always available. There is a range of acceptability above and below the desired ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of the mucolabial fold when developing impressions for complete dentures.

All patients have loose nonkeratinized unattached mucosa in the anterior labial vestibule. The degree of possible distortion varies with each patient and with different recording techniques. Some distortion is possible in all patients. Common errors made when manipulating this tissue during impression procedures for complete dentures have been described. An effort to compensate for the errors in the finished denture will not correct them. Manipulation of the mucolabial fold must be done correctly during the border molding procedure. If not, the only recourse may be to reline the denture, and care should be taken not to repeat the errors.