This study focuses on the optimization of the bonding conditions for adhesive joints, specifically targeting PA66/GF and epoxy/CF thermoset materials. The Box-Behnken (BB) design was employed for ...meticulous optimization, considering variables such as mixing ratio (M1), curing time (M2), and primer application (M3). The quadratic model derived from BB demonstrated synergistic effects between variables, allowing for an accurate prediction of response strength. Ultrasonic testing has emerged as a powerful nondestructive evaluation (NDE) tool for assessing bond quality in thermoset materials. PA66/GF and epoxy/CF specimens underwent thorough examination, emphasizing the advantages of non-destructive techniques over traditional destructive tests. The results of the destructive lap shear tests provide a comprehensive understanding of the bonding conditions. The control specimen exhibited a load of 23.7 MPa, while the S-5 group of specimens with modified bonding conditions exhibited higher maximum loads (24.9 MPa), and the S-25 group exhibited a higher maximum loads of 25.6 MPa. The results obtained in this study effectively separated the samples with different adhesion conditions from the control sample. The developed model for the variation of bonding conditions exhibited high prediction accuracy, supported by significant F-values from the ANOVA tests. The regression coefficient (R-square value) of 0.9557 underlines the strong correlation between the variables, with M3 and M2 identified as the key factors. Correlating ultrasonic signals with shear load reveals a strong predictive relationship, with ratios of 0.94 (PA66/GF-adhesive interface) and 0.96 (Epoxy/CF-adhesive interfaces). The model effectively discerns the need for epoxy/CF adhesive interfaces, highlighting potential challenges for the BB-based approach. As the study concludes, the abstract encapsulates the optimization, evaluation, and predictive capabilities of the proposed model for adhesive bonding conditions.
Structured Abstract Background There is a continuing debate on the best approach for endoscopically benign large polyps that are unsuitable for conventional endoscopic resection. This study aims to ...estimate the cancer risk in patients with endoscopically benign unresectable colonic polyps referred for surgery. Study Design Patients with an endoscopic diagnosis of benign adenoma deemed not amenable for endoscopic removal who underwent colectomy between 1997- 2012 were accessed. Patients with preoperative diagnoses of cancer, inherited polyposis syndrome, inflammatory bowel disease, and synchronous pathology requiring surgery were excluded. Results 439 patients 220(50.1%) men; median age 67(27-97) years underwent colectomy. Of 439 patients, 346(79%) underwent preoperative endoscopy at our institution for all polyps preoperative biopsy was benign. Most of the polyps were located in the right colon (394/439, 89.7%) with majority being in the cecum (199/394, 45.3%). Polyp morphology was as follows: sessile (n=252, 57.4 %), pedunculated (n=109, 24.8%) and flat (n=78, 17.8%). Endoscopic pathology revealed high-grade dysplasia in 88 (20%) patients. Mean colonoscopic and postoperative polyp sizes were 3.0 cm (range, 0.3-10) and 2.7 cm (range, 0-11) cm, respectively (p<0.001). Final surgical pathology revealed cancer in 37 patients (8%). Polyp location, morphology and histologic types were similar between the benign and malignant polyps. Cancer stages were: stage I (23 patients), stage II (11), and stage III (3). Conclusions For the majority of endoscopically benign colonic polyps an oncologic colonic resection may be unnecessary hence adaption of advanced endoscopic resection techniques or laparoscopic assisted polypectomy should be considered. When bowel resection is needed, the resection should be performed obeying oncologic principles and techniques.
Elderly patients undergoing colorectal surgery have increasingly become under scrutiny by accounting for the largest fraction of geriatric postoperative deaths and a significant proportion of all ...postoperative complications, including anastomotic leak.
This study aimed to determine predictors of anastomotic leak in elderly patients undergoing colectomy by creating a novel nomogram for simplistic prediction of anastomotic leak risk in a given patient.
This study was a retrospective review.
The database review of the American College of Surgeons National Surgical Quality Improvement Program was conducted at a single institution.
Patients aged ≥65 years who underwent elective segmental colectomy with an anastomosis at different levels (abdominal or low pelvic) in 2012-2013 were identified from the multi-institutional procedure-targeted database.
We constructed a stepwise multiple logistic regression model for anastomotic leak as an outcome; predictors were selected in a stepwise fashion using the Akaike information criterion. The validity of the nomogram was externally tested on elderly patients (≥65 years of age) from the 2014 American College of Surgeons National Surgical Quality Improvement Program colectomy-targeted database.
A total of 10,392 patients were analyzed, and anastomotic leak occurred in 332 (3.2%). Of the patients who developed anastomotic leak, 192 (57.8%) were men (p < 0.001). Based on unadjusted analysis, factors associated with an increased risk of anastomotic leak were ASA score III and IV (p < 0.001), chronic obstructive pulmonary disease (p = 0.004), diabetes mellitus (p = 0.003), smoking history (p = 0.014), weight loss (p = 0.013), previously infected wound (p = 0.005), omitting mechanical bowel preparation (p = 0.005) and/or preoperative oral antibiotic use (p < 0.001), and wounds classified as contaminated or dirty/infected (p = 0.008). Patients who developed anastomotic leak had a longer length of hospital stay (17 vs 7 d; p < 0.001) and operative time (191 vs 162 min; p < 0.001). A multivariate model and nomogram were created.
This study was limited by its retrospective nature and short-term follow-up (30 d).
An accurate prediction of anastomotic leak affecting morbidity and mortality after colorectal surgery using the proposed nomogram may facilitate decision making in elderly patients for healthcare providers.
This paper presents an efficient method for stress measurement propagation. Pulse-echo method are used as stress measurement method on railway wheels. Hard service conditions and brake failures can ...lead to dangerous stress on the railway wheels. Stress measurements so important for wheels. Especially wheel expose to severe drag braking conditions in freight service. Residual stresses can significantly reduce the engineering properties and fatigue life of materials such as railway components. The paper presents results of stress state investigation of ER7 steel. Finally, the article briefly discusses how to adopt the pulse-echo method to railway wheels. Reducing cost of residual stress measurement investigated.
Modified frailty index (mFI) has been proposed as a reliable tool in predicting postoperative outcomes after surgery. This study aims to evaluate whether mFI could be utilized to predict readmissions ...after colorectal resection for patients with cancer by using nationwide cohort.
Patients undergoing elective abdominal colorectal resection for colorectal cancer were reviewed from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) procedure-targeted database (2010–2012). A previously described mFI was calculated. Demographics, comorbidities, and 30-day postoperative complications were compared between patients who were readmitted or not after colorectal surgery.
A total of 7337 patients were identified with a mean age of 65.8(±13.6) years. Eight hundred seventy-one (11.8%) patients were readmitted at least once within 30 days. Age, gender, BMI, and other comorbidities were comparable between the groups. O approach, current smoking, mFI(>3/11), disseminating cancer, bleeding disorder and longer operative time were found to independently associated with readmission.
An 11-point modified frailty index as measured in NSQIP correlates with readmissions after colorectal resection in patients with colon and rectal cancer.
•mFI is a quick and simple tool that can predict readmissions after colorectal surgery.•Open approach, current smoking, disseminating cancer are associated with readmission.•Bleeding disorder and longer operative time are associated with readmission.
Background
Laparoscopic sigmoidectomy is the preferred approach in the elective surgical management of diverticulitis. However, it is unclear if the benefits of laparoscopy persist when operative ...times are prolonged. We aimed to investigate if the recovery benefits associated with laparoscopy are retained when operative times are long.
Methods
A retrospective review of a prospectively maintained database of patients who underwent elective laparoscopic sigmoidectomy from 2010–2015 at a single academic tertiary institution was performed. Operative times among laparoscopic completed cases were divided into quartiles, and patient outcomes were compared between the groups.
Results
A total of 466 patients (median age: 58 ± 11.6 years, 58% females) underwent sigmoidectomy: 430 completed laparoscopically and 36 (7.7%) converted. Median operative time in laparoscopically completed cases was 188 min (IQR 154–230). There were no differences in morbidity (
P
= 0.52) or readmission rates (
P
= 0.22) among the quartiles. The 2nd and 4th operative time quartiles were associated with significantly longer length of stay (LOS) when compared to the fastest quartile (
P
= 0.003 and
P
= 0.002, respectively), but there was no increase in LOS as operative times progressed between the 2nd, 3rd, and 4th quartiles. LOS after conversion was longer but did not reach statistical significance when compared to laparoscopically completed operations in the longest quartile (5.0 vs 6.5 days,
P
= 0.075)
Conclusions
Our data do not support preemptive conversion of laparoscopic sigmoidectomy to avoid prolonged operative times. As long as progress is safely being made, surgeons are justified to continue pursuing laparoscopic completion.
Purpose
Diverticular disease is one of the most common causes of acute lower gastrointestinal bleeding. We aimed to evaluate the natural history, follow-up, and risk factors associated with ...re-bleeding (recurrence) in patients with colonic diverticular bleeding.
Methods
We reviewed patients with proven colonic diverticular hemorrhage from September 1993 to June 2012 at our institution. Recurrence was the main outcome measure.
Results
We identified 78 out of 95 patients with proven diverticular bleed who were treated non-operatively and were followed up for a median of 57.1 months. Thirty-seven (47 %) of these patients with a median age of 67 years developed recurrent diverticular bleed after a median time of 8.1 months. The bleeding originated from the left colon in 78 (83 %) out of 95 patients in the first bleeding episode and 31(84 %) out of 37 patients during the recurrent bleeding episode. Thirty-six patients (97 %) with recurrent diverticular bleed required surgical intervention. Old age at the time of initial bleeding was associated with recurrence (
p
= 0.001). Patients with diverticulitis (
p
< 0.0001), peripheral vascular (
p
= 0.01), and chronic renal diseases (
p
= 0.047) were found to have an increased risk for recurrent colonic diverticular bleed. We only had one perioperative mortality due to postoperative sepsis. All other mortalities were not directly associated with surgery.
Conclusion
Patients with a history of colonic diverticular bleed are prone to recur shortly thereafter. Certain risk factors including increased age, documented diverticulitis, history of peripheral vascular disease, and chronic renal failure may predispose to recurrence.
Perineal hernia is a well-known, rare complication following abdominoperineal resection for rectal cancer. Due to its rarity, the literature on its surgical repair is comprised of case reports and ...small case series, and not one surgical approach has been established as superior.
This study aimed to identify the repair methods used at our institution and their outcomes. We hypothesized that a perineal approach would have a similar recurrence rate to a transabdominal repair with shorter hospital length of stay.
This study was a retrospective case series.
This study was conducted in a large, single institution setting.
Patients who underwent surgical repair for perineal hernia from January 2009 to December 2019 were included.
The primary outcomes were perineal hernia recurrence, surgical approach to repair, and length of stay.
We identified 36 patients who underwent surgical repair of perineal hernia at our institution. Twenty patients received neoadjuvant chemoradiation therapy. Most patients (29) had previously undergone abdominoperineal resection; 5 were robotic, 15 were laparoscopic, 1 was robotic converted to open, and 8 were open. Patients were repaired through a perineal approach (22) or transabdominally (14). The median length of stay was 4 days (1-12) after a perineal approach and 8 days (3-18) after a transabdominal approach. At a median follow-up of 12.7 months (1-72), there were 4 recurrences after perineal repair and 3 recurrences after transabdominal repair.
This study was limited by its small sample size (36), the retrospective and nonrandomized nature of the case series, and a lack of routine postoperative imaging. A median follow-up length of 12.7 months may not be adequate to detect all recurrences.
This case series supports the perineal approach for surgical repair; it should be the first approach considered, as it is less invasive and may be associated with shorter length of stay compared to an open transabdominal approach. Male gender and neoadjuvant chemotherapy may be possible risk factors for the development of perineal hernia after abdominoperineal resection. See Video Abstract at http://links.lww.com/DCR/B856.
ANTECEDENTES:La hernia perineal es una complicación rara y bien conocida después de la resección abdominoperineal por cáncer de recto. Debido a su rareza, la literatura sobre su reparación quirúrgica se compone de informes de casos y pequeñas series de casos, y ningún abordaje quirúrgico se ha establecido como superior.OBJETIVO:El presente estudio tuvo como objetivo identificar los métodos de reparación utilizados en nuestra institución y sus resultados. Presumimos que un abordaje perineal tendría una tasa de recurrencia similar a una reparación transabdominal, con una estancia hospitalaria más corta.DISEÑO:Ésta es una serie de casos retrospectiva.AJUSTES:El escenario fue una gran institución única.PACIENTES:Los pacientes que se sometieron a reparación quirúrgica por hernia perineal desde enero del 2009 hasta diciembre del 2019 se incluyeron en la revisión.PRINCIPALES MEDIDAS DE RESULTADO:Los resultados primarios fueron la recurrencia de la hernia perineal, el abordaje quirúrgico para la reparación y la duración de la estadía.RESULTADOS:Identificamos 36 pacientes que fueron sometidos a reparación quirúrgica de hernia perineal en nuestra institución. La mayoría de los pacientes recibieron quimiorradioterapia neoadyuvante (n = 20). La mayoría de los pacientes (n = 29) se habrían sometido previamente a una resección abdominoperineal (n = 5 robótica, n = 15 laparoscópica, n = 1 robótica convertida a abierta, n = 8 abierta). Los pacientes fueron reparados mediante un abordaje perineal (n = 22) o transabdominal (n = 14). La mediana de la estancia hospitalaria fue de 4 días (rango, 1-12) después de un abordaje perineal y de 8 días (rango 3-18) después de un abordaje transabdominal. En una mediana de seguimiento de 12,7 meses (rango, 1-72) hubo 4 recurrencias después de la reparación perineal y 3 recurrencias después de la transabdominal.LIMITACIONES:El tamaño de la muestra pequeño (n = 36), la naturaleza retrospectiva y no aleatorizada de la serie de casos, la falta de imágenes posoperatorias de rutina, la mediana de seguimiento de 12,7 meses puede no ser adecuada para detectar todas las recurrencias.CONCLUSIONES:Esta serie de casos apoya el abordaje perineal para la reparación quirúrgica; debe ser el primer abordaje considerado, ya que es menos invasivo y puede estar asociado con una estadía más corta en comparación con el abordaje transabdominal abierto. El sexo masculino y la quimioterapia neoadyuvante podrían ser posibles factores de riesgo para el desarrollo de hernia perineal después de la resección abdominoperineal. Consulte Video Resumen en http://links.lww.com/DCR/B856. (Traducción- Dr. Francisco M. Abarca-Rendon).
