Study on the anatomical dimensions of the human sigmoid colon

"Sigmoid take-off" to define recto-sigmoid junction and its impact on rectal cancer classification, staging, and management

AIM

The primary objective of this study was to determine the clinical impact of using sigmoid take-off (STO) in the management of rectal cancer. We also evaluated the inter-observer reliability in the identification of STO.

MATERIAL AND METHODS

This retrospective study reviewed staging MRI of patients with mid and high-rectal cancers performed between January 2019 and December 2022. The location of the tumour was reclassified based on STO as defined by D'Souza et al. (2018) and compared with the location determined based on distance from the anal verge. The proportions of cases that show a change in tumour location from rectal cancer to sigmoid cancer and the potential change in treatment were noted. The interobserver agreement for the location of STO and the location of tumours from STO was studied among four subspecialised abdominal radiologists.

RESULTS

Out of 134 rectal cancer patients included, STO-based assessment resulted in the reclassification of 13.4% (n=18) cases into sigmoid cancer. There was, however, no change in the stage of cancer. Among these 18 patients, there would have been a change in management in 5 patients had the initial assessment been a sigmoid cancer. There was excellent agreement among the radiologists for measuring the distance of STO from the anal verge (ICC = 0.883, p<0.001) and determining the location of the tumour based on STO (K = 0.82, p<0.001).

CONCLUSIONS

Using STO changed the location of tumours in 13.4% of high- and mid-rectal cancers. There was excellent agreement among radiologists regarding determining STO and identifying tumour locations using STO.

Experimental Measurements of the Length of the Human Colon: A Systematic Review and Meta-Analysis

PURPOSE

Knowledge of the length of the colon is relevant to understanding physiological and pathological function. It also has implications for diagnostic and clinical interventions, as well as for the design of delayed-release drug formulations and drug disposition modeling.

METHODS

Over the years, a range of different experimental methods have been employed to assess colon length. These methods vary from direct measurements on cadavers and during intraoperative procedures to measurements obtained from endoscopic and medical imaging techniques. However, no systematic review or meta-analysis of these findings has yet been carried out. In this systematic review, we identified 31 published experimental studies that measured the length of the human colon and/or its segments.

RESULTS

We synthesized the available data, comprising colon length measurements from 5741 adults and 337 children and young people, in a meta-analysis. The data contribute to our understanding of colon morphology and may have implications for clinical practice, particularly for colonoscopy and preoperative planning of surgical resections. Additionally, this review provides potential insights into anatomical correlates of functional diseases, such as constipation.

CONCLUSIONS

This review highlights that non-invasive, non-destructive diagnostic imaging techniques, such as magnetic resonance imaging (MRI), can provide more physiologically relevant measurements of colon length. However, there is a need for more standardized measurement protocols and for additional pediatric data.

The role of sigmoid colon anatomic dimensions in the development of sigmoid volvulus, North-Western Ethiopia

Introduction

Sigmoid colon anatomic dimensions have been studied to have roles in the occurrence of sigmoid volvulus; however, these studies are few in number and failed to control the confounding effect of acute sigmoid obstruction on the anatomic dimensions. The main objective of this study was to assess the role of sigmoid colon anatomic dimensions in the development of sigmoid volvulus controlling the effect of acute sigmoid obstruction on the anatomic dimensions.

Materials and methods

The study was carried out from Dec, 2019 to April, 2021 at Tibebe Ghion Specialized Hospital and Felege Hiwot Comprehensive Specialized Hospital, two referral hospitals in Bahir Dar city, North-Western Ethiopia to compare sigmoid anatomic dimensions among three independent groups of participants: patients with no history of sigmoid volvulus (I), those for whom elective surgery was done after non-surgical detorsion of sigmoid volvulus (II), and patients for whom emergency surgery was done for sigmoid volvulus (III). The anatomic dimensions were compared using fixed effects one-way ANOVA or Kruskal-Wallis H test at p-value ≤ .05 (two-sided) and Tukey method or Dunn-Bonferroni’s test was used for post-hoc comparisons.

Results

A total of 66 consecutive eligible patients (22 for each of the three groups) were included and analyzed in the study. The means of anatomic dimensions (in cm) for groups (I, II, III) were: sigmoid colon length-SCL (35.91, 71.07, 80.86), meso-sigmoid height-MSH (17.11, 26.52, 28.86), meso-sigmoid maximal width-MSMW (9.70, 14.89,16.80), and meso-sigmoid root width-MSRW (8.34, 7.48, 8.11). SCL, MSH, MSMW, MSH/MSRW, and MSMW/MSRW were found to be statistically significantly different in patients with sigmoid volvulus. MSRW and MSH/MSMW were not different between the study groups.

Conclusion

A long sigmoid colon with long and wide mesentery, but with a constant base is highly likely to predispose individuals to sigmoid volvulus.

Management of acute sigmoid volvulus: A tunisian experience

BACKGROUND/OBJECTIVE

Sigmoid volvulus is the most common type of volvulus. Its epidemiological features, as well as its management, differ between developed and developing countries. This work aims to analyze the epidemiological features thus allowing to compare them to the rest of the "volvulus belt'' and assess the surgical management of sigmoid volvulus in Tunisia.

METHOD

This is a retrospective review of 64 patients with sigmoid volvulus treated in the General Surgery department of Jendouba Hospital. January 2005-December 2019.

RESULTS

64 patients were treated for acute sigmoid volvulus. The sex ratio male to female ratio was 5.4/1 with male predominance. 5.4:1 (54 males to 10 females). The mean age was 62 years. The classic triad of intestinal occlusion was reported in 56 patients. The mean duration of symptoms was 4.2 days. An accurate preoperative diagnosis was made in 58 cases. Forty patients had a viable bowel obstruction, and all of them had a resection and primary anastomosis. Sixteen patients had a gangrenous bowel obstruction, of which 6 patients had resection-primary anastomosis, and 10 had Hartmann's procedure. Out of the total five deaths reported, there were only two among patients who had resection-primary anastomosis for gangrenous bowel obstruction. The most common postoperative complication was wound infections in 5 cases. The median length of hospital stay following surgery was 8 days. No recurrences of volvulus after a median follow-up of 11 months.

CONCLUSIONS

Although Tunisia belongs to the volvulus belt, the epidemiologic features of sigmoid volvulus tend rather be similar to those of developed countries. The use of primary surgery, if no endoscopy is performed, is a good alternative. For patients who have contraindications for endoscopic treatment, surgical treatment is the only option.

Surgical Management of Sigmoid Volvulus: A Multicenter Observational Study

Purpose: This study aimed to evaluate real-world clinical outcomes from surgically treated patients for sigmoid volvulus.Methods: Five tertiary centers participated in this retrospective study with data collected from October 2003 through September 2018, including demographic information, preoperative clinical data, and information on laparoscopic/open and elective/emergency procedures. Outcome measurements included operation time, postoperative hospitalization, and postoperative morbidity.Results: Among 74 patients, sigmoidectomy was the most common procedure (n = 46), followed by Hartmann’s procedure (n = 23), and subtotal colectomy (n = 5). Emergency surgery was performed in 35 cases (47.3%). Of the 35 emergency patients, 34 cases (97.1%) underwent open surgery, and a stoma was established for 26 patients (74.3%). Elective surgery was performed in 39 cases (52.7%), including 21 open procedures (53.8%), and 18 laparoscopic surgeries (46.2%). Median laparoscopic operation time was 180 minutes, while median open surgery time was 130 minutes (P < 0.001). Median postoperative hospitalization was 11 days for laparoscopy and 12 days for open surgery. There were 20 postoperative complications (27.0%), and all were resolved with conservative management. Emergency surgery cases had a higher complication rate than elective surgery cases (40.0% vs. 15.4%, P = 0.034).Conclusion: Relative to elective surgery, emergency surgery had a higher rate of postoperative complications, open surgery, and stoma formation. As such, elective laparoscopic surgery after successful sigmoidoscopic decompression may be the optimal clinical option.

Surgical Management of Sigmoid Volvulus: A Multicenter Observational Study

Purpose

This study aimed to evaluate real-world clinical outcomes from surgically treated patients for sigmoid volvulus.

Methods

Five tertiary centers participated in this retrospective study with data collected from October 2003 through September 2018, including demographic information, preoperative clinical data, and information on laparoscopic/open and elective/emergency procedures. Outcome measurements included operation time, postoperative hospitalization, and postoperative morbidity.

Results

Among 74 patients, sigmoidectomy was the most common procedure (n = 46), followed by Hartmann’s procedure (n = 23), and subtotal colectomy (n = 5). Emergency surgery was performed in 35 cases (47.3%). Of the 35 emergency patients, 34 cases (97.1%) underwent open surgery, and a stoma was established for 26 patients (74.3%). Elective surgery was performed in 39 cases (52.7%), including 21 open procedures (53.8%), and 18 laparoscopic surgeries (46.2%). Median laparoscopic operation time was 180 minutes, while median open surgery time was 130 minutes (P < 0.001). Median postoperative hospitalization was 11 days for laparoscopy and 12 days for open surgery. There were 20 postoperative complications (27.0%), and all were resolved with conservative management. Emergency surgery cases had a higher complication rate than elective surgery cases (40.0% vs. 15.4%, P = 0.034).

Conclusion

Relative to elective surgery, emergency surgery had a higher rate of postoperative complications, open surgery, and stoma formation. As such, elective laparoscopic surgery after successful sigmoidoscopic decompression may be the optimal clinical option.

Exploration of colonic looping patterns in undisturbed cadaveric specimens

INTRODUCTION

This study examines sex differences in the disposition of the sigmoid and transverse segments of the colon in undisturbed cadaveric abdomens and relates these findings to the anecdotal observation that colonoscopy is more challenging in females through the formation of tortuous bowel loops.

MATERIALS AND METHODS

One hundred and twenty two undisturbed cadaveric abdomens were inspected. Three distinct configuration grades were separately assigned to the sigmoid and transverse segments of the colon on the basis of the pattern of the bowel loops observed in situ. Pearson's chi-squared test was used to analyze sex differences in bowel loop configuration and Spearman's rank correlation coefficient was calculated to identify co-occurrence of configuration grades in the subjects.

RESULTS

For the transverse segment, females had higher configuration grades corresponding to longer bowel loops with greater redundancy, compared to males (p = .000047). There was no sex difference in the sigmoid segment grade (p = .21636). Sigmoid and transverse segment grades were highly correlated in the subjects (coefficient = 0.9994).

CONCLUSION

Sex differences in the configuration grades of the sigmoid or transverse colonic segments may be a significant contributing factor to increased difficulty of colonoscopy in females.

The effect of pericolic lymph nodes metastasis beyond 10 cm proximal to the tumor on patients with rectal cancer

Background

This study aims to determine the real incidence of pericolic lymph nodes metastasis beyond 10 cm proximal to the tumor (pPCN) and its prognostic significance in rectal cancer patients.

Methods

Consecutive patients with rectal cancer underwent curative resection between 2015 and 2017 were included. Margin distance was marked and measured in vivo and lymph nodes were harvested on fresh specimens. Clinicopathological characteristics and oncological outcomes (3-year overall survival (OS) and disease-free survival (DFS)) were analyzed between patients with pPCN and patients without pPCN (nPCN).

Results

There were 298 patients in the nPCN group and 14 patients (4.5%) in pPCN group. Baseline characteristics were balanced except more patients received preoperative or postoperative chemoradiotherapy in pPCN group. Preoperative more advanced cTNM stage (log-rank p = 0.005) and intraoperative more pericolic lymph nodes beyond 10 cm proximal to the tumor (PCNs) (log-rank p = 0.002) were independent risk factors for pPCN. The maximum short-axis diameter of mesenteric lymph nodes ≥8 mm was also contributed to predicting the pPCN. pPCN was an independent prognostic indicator and associated with worse 3-year OS (66% vs 91%, Cox p = 0.033) and DFS (58% vs 92%, Cox p = 0.012).

Conclusion

The incidence of pPCN was higher than expected. Patients with high-risk factors (cTNM stage III or more PCNs) might get benefits from an extended proximal bowel resection to avoid residual positive PCNs.

Muscularis propria detected at colonic biopsy is not a critical value

Perforation is a rare but potentially serious complication of cold forceps colonic biopsies. The presence of muscularis propria might portend increased risk of perforation and warrant urgent communication with endoscopists. However, identifying muscularis propria at time of biopsy is difficult for many reasons, including histologic overlap with muscularis mucosa. Incidental muscularis propria obtained in this manner has yet to be studied. Our objectives were to characterize the morphology of muscularis propria obtained incidentally via cold forceps colonic biopsies, establish practical criteria for diagnosing muscularis propria, and determine whether diagnosing muscularis propria correlates with perforation clinically. We retrospectively reviewed 3 specimens from nontargeted cold forceps colonic biopsies for which pieces of muscularis propria were presumed to be visualized based on larger size or lower nuclear density compared to the corresponding muscularis mucosa. These specimens were then compared to normal transmural control tissue from colectomy to confirm whether nuclear density or other features could distinguish muscularis propria from muscularis mucosa. Muscularis propria in the control tissue had lower nuclear density, smoother cytoplasmic texture, and more cytoplasmic pallor compared to the muscularis mucosa in the control tissue. This constellation of features was seen in all 3 specimens obtained via biopsy and therefore confirmed the presence of muscularis propria, though all patients lacked perforation clinically. Large size, low nuclear density, smooth cytoplasm, and pale cytoplasm identify objects as muscularis propria at time of colonic biopsy. The presence of muscularis propria fails to correlate with perforation clinically and does not warrant urgent communication.

Endoscopic Detorsion Results in Sigmoid Volvulus: Single-Center Experience

Endoscopic detorsion is the first-line recommended treatment modality in sigmoid volvulus patients who have no peritoneal irritation signs on admission. In this paper, we present the results of endoscopic detorsion procedures applied at the time of presentation with the diagnosis of sigmoid volvulus and review the current literature about this topic.

Sigmoid volvulus after CABG surgery

We report a case of a geriatric patient who underwent CABG and developed sigmoid volvulus (SV) with recurrence. SV is a rarely reported complication of CABG. Timely diagnosis, management, and follow-up are strictly advised, particularly in geriatric patients. Immediate surgical measures are required to prevent volvulus-associated ischemia.

The large intestine from fetal period to adulthood and its impact on the course of colonoscopy

The human large intestine in the living adult has a total length of about 1300 mm, ranging from 1100 to 2108 mm. The development of the gut continues after birth, up to the age 4-5. The large intestine ascends at the beginning in the right abdominal quadrant, then it traverses the abdominal cavity, and finally it descends to the anus. The left and right colic flexures are the basic flexions between the transverse, ascending and descending colon, respectively. Additionally, there are secondary bendings between intestinal segments. The angles between the neighbouring parts can vary between examined subjects. Most of the angulations can be found in the transverse (range 2-9) and sigmoid colon (range 1-9), making them the most troublesome parts to pass with a colonoscope. Colonoscopy (usually performed in the left lateral or supine position) is one of the most important examination of the large intestine mucus membrane. During this procedure the endoscope is passed through the colon into the cecum or terminal ilium. The individual anatomical features (tortuosity, supernumerary loops and elongation) may slow down or interfere with the progress of the scope. We summarize current knowledge on the human large intestine from the fetal period to adulthood and carve out some aspects that are currently less known to colonoscopists.

Phenotypic and genotypic differences in colorectal carcinoma among Caucasians, Asians, and Hispanics lack statistical significance

Colorectal carcinoma (CRC) has been shown to have both genetic and environmental factors that can promote carcinoma development. Previous studies have found ethnic differences in the distribution of molecular phenotypes of CRC. Very little specific data exist regarding Hispanic CRC, and these data primarily focus on epidemiology or location of carcinoma. Our retrospective study analyzed 562 Caucasian, Asian, and Hispanic CRC patients at the UCI Medical Center from 2004 to 2012. The results showed that there were no statistically significant differences with respect to mean age, gender or site of carcinoma among the three ethnic groups. There were no statistically significant differences among the three ethnicities with respect to rates of MSI, mutated BRAF, and mutated KRAS. The Caucasian group had a non-significant higher rate of MSI (15%) and BRAF mutation (12%) than the Asian and Hispanic groups. Hispanics had a non-significant higher rate of KRAS mutation (59%) than Caucasians (38%) and Asians (37%). The results of this study demonstrated a higher rate of MSI and BRAF mutation in the Caucasian group and a higher rate of KRAS mutation in the Hispanic group, however differences were not statistically significant.

Autonomous Retroflexion of a Magnetic Flexible Endoscope

Retroflexion during colonoscopy is typically only practiced in the wider proximal and distal ends of the large intestine owing to the stiff nature of the colonoscope. This inability to examine the proximal side of the majority of colon folds contributes to today's suboptimal colorectal cancer detection rates. We have developed an algorithm for autonomous retroflexion of a flexible endoscope that is actuated magnetically from the tip. The magnetic wrench applied on the tip of the endoscope is optimized in real-time with data from pose detection to compute motions of the actuating magnet. This is the first example of a completely autonomous maneuver by a magnetic endoscope for exploration of the gastrointestinal tract. The proposed approach was validated in plastic tubes of various diameters with a success rate of 98.8% for separation distances up to 50 mm. Additionally, a set of trials was conducted in an excised porcine colon observing a success rate of 100% with a mean time of 19.7 s. In terms of clinical safety, the maximum stress that is applied on the colon wall with our methodology is an order of magnitude below what would damage tissue.

Volvulus of the Small Bowel and Colon

Volvulus of the intestines may involve either the small bowel or colon. In the pediatric population, small bowel volvulus is more common, while in the adult population, colonic volvulus is more often seen. The two most common types of colonic volvulus include sigmoid and cecal volvulus. Prompt diagnosis and treatment is imperative, otherwise bowel ischemia may ensue. Treatment often involves emergent surgical exploration and bowel resection.

[Anatomical study of pelvic colon]

OBJECTIVES

Identifying the different kinds of anatomical sigmoid colon in our environment and determine what exposes the most to the occurrence of pelvic colon volvulus.

MATERIALS AND METHODS

This is a transverse prospective study from 1 January 2007 to 31 December 2012 on a series of 63 patients (33 men and 30 women) who underwent laparotomy for non-colonic pathologies. For all patients, the following parameters were recorded: C1: total length of the pelvic colon; C2: the length of the root of the meso-sigmoid; C3: the height of the meso-sigmoid; C4: maximum width of the meso-sigmoid.

RESULTS

C1 through the entire series was 61,3cm. C2 average was 5.5cm. C3 height and maximum width C4 were on average 14,6cm and 7.6cm, respectively. Comparison of parameters in men and women showed no significant difference.

CONCLUSION

This study allows us to know the different types of pelvic colons among the population of our operated patients. The measurements performed on the pelvic colon of patients presenting volvulus will help to attribute objectively the true authorship of this surgical emergency to an anatomical type of pelvic colon.

Total robotic radical rectal resection with da Vinci Xi system: single docking, single phase technique

OBJECTIVE

This study aims to assess the advantages of Da Vinci Xi system in rectal cancer surgery. It also assesses the initial oncological outcomes after rectal resection with this system from a tertiary cancer center in India.

INTRODUCTION

Robotic rectal surgery has distinct advantages over laparoscopy. Total robotic resection is increasing following the evolution of hybrid technology. The latest Da Vinci Xi system (Intuitive Surgical, Sunnyvale, USA) is enabled with newer features to make total robotic resection possible with single docking and single phase.

METHODS AND RESULTS

Thirty-six patients underwent total robotic resection in a single phase and single docking. We used newer port positions in a straight line. Median distance from the anal verge was 4.5 cm. Median robotic docking time and robotic procedure time were 9 and 280 min, respectively. Median blood loss was 100 mL. One patient needed conversion to an open approach due to advanced disease. Circumferential resection margin and longitudinal resection margins were uninvolved in all other patients. Median lymph node yield was 10. Median post-operative stay was 7 days. There were no intra-operative adverse events.

CONCLUSION

The latest Da Vinci Xi system has made total robotic rectal surgery feasible in single docking and single phase. With the new system, four arm total robotic rectal surgery may replace the hybrid technique of laparoscopic and robotic surgery for rectal malignancies. The learning curve for the new system appears to be shorter than anticipated. Early perioperative and oncological outcomes of total robotic rectal surgery with the new system are promising. Copyright © 2016 John Wiley & Sons, Ltd.

Assessment of normal left atrial appendage anatomy and function over gender and ages by dynamic cardiac CT

OBJECTIVES

The aim of this study was to evaluate variations in anatomy and function according to age and gender using cardiac computed tomography (CT) in a large prospective cohort of healthy patients.

BACKGROUND

The left atrial appendage (LAA) is considered the most frequent site of intracardiac thrombus formation. However, variations in normal in vivo anatomy and function according to age and gender remain largely unknown.

METHODS

Three-dimensional (3D) cardiac reconstructions of the LAA were performed from CT scans of 193 consecutive patients. Parameters measured included LAA number of lobes, anatomical position of the LAA tip, angulation measured between the proximal and distal portions, minimum (iVolmin) and maximum (iVolmax) volumes indexed to body surface area (BSA), and ejection fraction (LAAEF). Relationship with age was assessed for each parameter.

RESULTS

We found that men had longer and wider LAAs. The iVolmin and iVolmax increased by 0.23 and 0.19 ml per decade, respectively, while LAAEF decreased by 2% per decade in both sexes.

CONCLUSIONS

Although LAA volumes increase, LAAEF decreases with age in both sexes.

KEY POINTS

• Variations in normal left atrial appendage in vivo anatomy and function remain largely unknown. • Cardiac CT is reliable for left atrial appendage volume measurements. • Although LAA volumes increase, LAAEF decreases with age in both sexes.

Morphology of Sigmoid Colon in South Indian Population: A Cadaveric Study

INTRODUCTION

Sigmoid volvulus is a common etiological factor in acute large bowel obstruction. The increased length of sigmoid colon is attributed as one of the causes of sigmoid volvulus.

AIM

The aim of this study was to find the morphology of sigmoid colon in South Indian population using cadavers.

MATERIALS AND METHODS

The present study was performed with 31 cadavers used for teaching purpose. The sigmoid colon was classified into classical, long-narrow and long- broad types by their disposition in the abdominal cavity. The sigmoid loop's relation to pelvic brim was also observed and grouped as pelvic and suprapelvic in position. The length of sigmoid colon along the mesenteric and antimesenteric border, height and width of sigmoid mesocolon in relation to the pelvic brim and the root of mesentery were measured in the study.

RESULTS

The study showed that the majority of the sigmoid colons fell into the classical type (47.6%). The sigmoid colon in pelvic position was significantly more prevalent. The mean length of sigmoid colon was 15.2 ± 4.4cm and 19.2 ± 6cm considering the pelvic brim and root of mesentery as reference points of measurement respectively. The mean length along antimesenteric border was 22.3 ± 7.9cm and 25 ± 8.7cm along the same reference points. The mean length of mesocolon height was 6.5 ± 3cm with reference to pelvic brim and 7.3 ± 3cm with reference to root of Sigmoid mesocolon respectively. The mean width of mesocolon was 7.4 ± 3cm (pelvic brim) and 8 ± 2cm (root of Sigmoid mesocolon) There was a positive correlation of sigmoid colon length with the height of the mesocolon. The gender analysis showed that males had statistically significant longer sigmoid colon and mesocolon.

CONCLUSION

This study documents that the South Indian population has a more classical type of sigmoid colon and that the anatomical dimensions of sigmoid colon and its mesocolon is significantly longer in males.

Sigmoid volvulus and ileo-sigmoid knotting: a five-year experience at a tertiary care hospital in Tanzania

Background

Sigmoid volvulus is a common cause of intestinal obstruction in developing countries where it affects relatively young people compared to developed countries. No prospective study has been done on this subject in Tanzania and Bugando Medical Centre in particular. This study describes in our region, the clinical presentation, management and outcome of sigmoid volvulus.

Methods

This was a descriptive prospective study of patients operated for sigmoid volvulus at Bugando Medical Centre from March 2009 to February 2014.

Results

A total of 146 patients (M: F = 5.1: 1) representing 14.2% of all cases of bowel obstruction were studied. The median age at presentation was 48 years. The disease significantly affected the older males compared with females (P = 0.012). The majority of the patients 102, (93.2%) presented acutely and had to undergo emergency surgical intervention, the rest were either sub-acute or chronic. Out of the 146 patients studied, 24 (16.4%) had ileo-sigmoid knotting. The majority of patients, 102(69.9%) were treated with resection and primary anastomosis, of which 63.0% were emergency cases. Colostomy was offered to 30.1% of cases. No patient had sigmoidoscopic derotation. Complications mainly surgical site infections were reported in 20.5% of cases. The overall median length of hospital stay was 14 days. Overall mortality rate was 17.1%. The main predictors of mortality were advanced age (>60 years), concomitant medical illness, late presentation (≥24 hours), presence of shock on admission and presence of gangrenous bowel (P < 0.001). The follow up of patients in this study was generally poor as more than half of patients were lost to follow up.

Conclusion

Sigmoid volvulus is not uncommon in our setting and commonly affects males than females. Most of the patients presented acutely, requiring immediate resuscitation and surgical approach. Findings from this study suggest that in viable bowel, sigmoid resection and primary anastomosis is feasible as it may not adversely affect outcome. Temporary colostomy should be considered if the bowel is gangrenous or perforated. Early diagnosis and timely definitive treatment are essential in order to decrease the morbidity and mortality associated with this disease.

More patients should undergo surgery after sigmoid volvulus

AIM: To assess the outcome of patients treated conservatively vs surgically during their first admission for sigmoid volvulus.

METHODS: We conducted a retrospective study of 61 patients admitted to Aarhus University Hospital in Denmark between 1996 and 2011 for their first incidence of sigmoid volvulus. The condition was diagnosed by radiography, sigmoidoscopy or surgery. Patients treated with surgery underwent either a sigmoid resection or a percutaneous endoscopic colostomy (PEC). Conservatively treated patients were managed without surgery. Data was recorded into a Microsoft Access database and calculations were performed with Microsoft Excel. Kaplan-Meier plotting and Mantel-Cox (log-rank) testing were performed using GraphPad Prism software. Mortality was defined as death within 30 d after intervention or surgery.

RESULTS: Among the total 61 patients, 4 underwent emergency surgery, 55 underwent endoscopy, 1 experienced resolution of the volvulus after contrast enema, and 1 died without treatment because of large bowel perforation. Following emergency treatment, 28 patients underwent sigmoid resection (semi-elective n = 18; elective n = 10). Two patients who were unfit for surgery underwent PEC and both died, 1 after 36 d and the other after 9 mo, respectively. The remaining 26 patients were managed conservatively without sigmoid resection. Patients treated conservatively on their first admission had a poorer survival rate than patients treated surgically on their first admission (95%CI: 3.67-14.37, P = 0.036). Sixty-three percent of the 26 conservatively treated patients had not experienced a recurrence 3 mo after treatment, but that number dropped to 24% 2 years after treatment. Eight of the 14 patients with recurrence after conservative treatment had surgery with no 30-d mortality.

CONCLUSION: Surgically-treated sigmoid volvulus patients had a higher long-term survival rate than conservatively managed patients, indicating a benefit of surgical resection or PEC insertion if feasible.

Surface area of the digestive tract - revisited

BACKGROUND

According to textbooks, the human gut mucosa measures 260-300 m(2), that is, in the order of a tennis court. However, the quantitative data are incomplete and sometimes conflicting.

OBJECTIVES

To review the literature regarding the mucosal surface area of the human digestive tract; to collect morphometric data from the parts of the gut where such data are missing; and to recalculate the mucosal surface area of the intestine in man.

METHODS

With focus on the intestine, we carried out morphometry by light and electron microscopy on biopsies from healthy adult volunteers or patients with endoscopically normal mucosae.

RESULTS

Literature review of intubation or radiological methods indicates an oroanal length of ∼5 m, two-third of which refers to the small intestine. However, there is a considerable variation between individuals. The inner diameter of the small intestine averages 2.5 cm and that of the large intestine averages 4.8 cm. The mucosa of the small intestine is enlarged ∼1.6 times by the plicae circulares. Morphometric data obtained by light and electron microscopy of biopsies demonstrate that villi and microvilli together amplify the small intestinal surface area by 60-120 times. Surface amplification due to microvilli in the colon is ∼6.5 times. The mean total mucosal surface of the digestive tract interior averages ∼32 m(2), of which about 2 m(2) refers to the large intestine.

CONCLUSION

The total area of the human adult gut mucosa is not in the order of tennis lawn, rather is that of half a badminton court.

Mechanical analysis of insertion problems and pain during colonoscopy: why highly skill-dependent colonoscopy routines are necessary in the first place... and how they may be avoided

BACKGROUND

Colonoscopy requires highly skill-dependent manoeuvres that demand a significant amount of training, and can cause considerable discomfort to patients, which increases the use of sedatives. Understanding the underlying fundamental mechanics behind insertion difficulties and pain during colonoscopy may help to simplify colonoscopy and reduce the required extent of training and reliance on sedatives.

METHODS

A literature search, anatomical studies, models of the colon and colonoscope, and bench tests were used to qualitatively analyze the fundamental mechanical causes of insertion difficulties and pain. A categorized review resulted in an overview of potential alternatives to current colonoscopes.

RESULTS

To advance a colonoscope through the colon, the colon wall, ligaments and peritoneum must be stretched, thus creating tension in the colon wall, which resists further wall deformation. This resistance forces the colonoscope to bend and follow the curves of the colon. The deformations that cause insertion difficulties and pain (necessitating the use of complex conventional manoeuvres) are the stretching of ligaments, and stretching of colon wall in the transverse and longitudinal directions, and the peritoneum.

CONCLUSIONS

Four fundamental mechanical solutions to prevent these deformations were extracted from the analysis. The current results may help in the development of new colonoscopy devices that reduce - or eliminate - the necessity of using highly skill-dependent manoeuvres, facilitate training and reduce the use of sedatives.

Article Commentary: The Twisted Colon: A Review of Sigmoid Volvulus

Sigmoid volvulus (SV) is the third leading cause of colon obstruction in adults. In infants and children, it is exceedingly rare with only sporadic cases reported so far. SVs from secondary causes, with congenital megacolon being the most important, are nevertheless more common in young people. The etiology of this disorder is not completely understood. It is known to occur in the setting of redundant sigmoid loop, which rotates around its narrow and elongated mesentery. Although the latter occurs in the setting of constipation, a congenitally elongated colon, and other predisposing factors, there is no consensus on the precipitating factor leading to SV formation. The symptoms are suggestive of small bowel obstruction, but the presentations can be acute or indolent. Plain abdominal radiography is used to diagnose SV in most cases with computed tomography scan or magnetic resonance imaging as the confirmatory tests when necessary. After it has been untwisted, the definitive and standard therapy for SV is sigmoid resection and primary anastomosis. The nonresective alternatives have also been widely used with mixed success, but a large, randomized controlled trial is needed to compare their efficacy with resection and primary anastomosis. Laparoscopic surgery in SV management is unwarranted and costly. Complications of SV include hemorrhagic infarction, perforation, septic shock, and death. The mortality data from SV vary, but the latest literature cites an overall range of 14 to 45 per cent.

An observational study addressing the anatomic basis of mesosigmoidopexy as a rational treatment of non-gangrenous sigmoid volvulus

Sigmoid volvulus is a common cause of bowel obstruction. We describe mesosigmoidopexy, an accepted surgical technique for the management of non-gangrenous sigmoid volvulus, and provide anatomic correlations supporting the therapy. Mesosigmoidopexy should be considered as a rational alternative to resection and anastomosis when operating on non-gangrenous sigmoid volvulus.

Preliminary development of the Active Colonoscopy Training Model

Formal colonoscopy training requires a significant amount of time and effort. In particular, it requires actual patients for a realistic learning experience. The quality of colonoscopy training varies, and includes didactic courses and procedures proctored by skilled surgeons. A colonoscopy training model is occasionally used as part of the training method, but the effects are minute due to both the simple and tedious training procedures. To enhance the educational effect of the colonoscopy training model, the Active Colonoscopy Training Model (ACTM) has been developed. ACTM is an interactive colonoscopy training device which can create the environment of a real colonoscopy procedure as closely as possible. It comprises a configurable rubber colon, a human torso, sensors, a display, and the control part. The ACTM provides audio and visual interaction to the trainee by monitoring important factors, such as forces caused by the distal tip and the shaft of the colonoscope and the pressure to open up the lumen and the localization of the distal tip. On the computer screen, the trainee can easily monitor the status of the colonoscopy, which includes the localization of the distal tip, maximum forces, pressure inside the colon, and surgery time. The forces between the rubber colon and the constraints inside the ACTM are measured and the real time display shows the results to the trainee. The pressure sensors will check the pressure at different parts of the colon. The real-time localized distal tip gives the colonoscopy trainee easier and more confident operation without introducing an additional device in the colonoscope. With the current need for colonoscopists and physicians, the ACTM can play an essential role resolving the problems of the current colonoscopy training model, and significantly improve the training quality of the colonoscopy.

Sigmoid colon morphology in the population groups of Durban, South Africa, with special reference to sigmoid volvulus

Sigmoid volvulus demonstrates geographical, racial, and gender variation. This autopsy study was undertaken to establish morphological differences of the sigmoid colon and its mesocolon in which the length and other characteristics were assessed. A total of 590 cadavers were examined (403 African, 91 Indian, and 96 White). Length and height of the sigmoid colon and mesocolon were significantly longer in Africans, and mesocolon root was significantly narrower in Africans. Mesocolic ratio for Africans, Indians, and Whites was 1.1 ± 0.8, 1.8 ± 0.7, and 1.9 ± 1.0, respectively. Africans had a significantly high incidence of redundant sigmoid colon with the long-narrow type and suprapelvic position predominating (P = 0.003); the opposite applied to the classic type. There was no difference in sigmoid colon length, mesocolon height, and width between males and females in all population groups. Among Africans, the long-narrow type was more common in males, and the classic and long-broad types were more common in females. Splaying of teniae coli and thickening of the mesentery were more common in Africans. Tethering of the sigmoid colon to the posterior abdominal wall was less common in Africans compared with other population groups. In conclusion, the sigmoid colon was longer, and the sigmoid mesocolon root was narrower in Africans compared with the other population groups, and the sigmoid colon had a suprapelvic disposition among Africans. In Africans, the sigmoid colon was longer in males with a long-narrow shape. These differences may explain geographical and racial differences in sigmoid volvulus.

The role of the anatomy of the sigmoid colon in developing sigmoid volvulus: a case-control study

Sigmoid volvulus is a common condition throughout much of the world. To this date, there are no adequately controlled clinical trials examining the role of anatomy in sigmoid volvulus. Therefore, the objective of this study was to determine if the anatomic dimensions of the sigmoid colon differ in sigmoid volvulus compared to controls. This prospective case-control study was conducted at Kamuzu Central Hospital, Lilongwe, Malawi. Cases included individuals 18 years or older with surgically confirmed sigmoid volvulus, while controls included individuals undergoing surgery for reasons unrelated to the descending or sigmoid colon, or rectum. Intraoperative measurements of the sigmoid colon were taken, including mesosigmoid root width and mesosigmoid length. A total of 26 cases and 12 controls were enrolled. When compared to controls, the mesosigmoid of cases had a greater length and maximal width; however, mesosigmoid root width was similar between groups. These findings support the assertion that sigmoid volvulus is due to a long and wide mesosigmoid that rotates on a constant mesosigmoid root width. This is the first adequately controlled trial examining anatomy in sigmoid volvulus and provides strong evidence that refines prior hypotheses regarding the anatomic basis of sigmoid volvulus.

Sigmoid volvulus

In sigmoid volvulus (SV), the sigmoid colon wraps around itself and its mesentery. SV accounts for 2% to 50% of all colonic obstructions and has an interesting geographic dispersion. SV generally affects adults, and it is more common in males. The etiology of SV is multifactorial and controversial; the main symptoms are abdominal pain, distention, and constipation, while the main signs are abdominal distention and tenderness. Routine laboratory findings are not pathognomonic: Plain abdominal X-ray radiographs show a dilated sigmoid colon and multiple small or large intestinal air-fluid levels, and abdominal CT and MRI demonstrate a whirled sigmoid mesentery. Flexible endoscopy shows a spiral sphincter-like twist of the mucosa. The diagnosis of SV is established by clinical, radiological, endoscopic, and sometimes operative findings. Although flexible endoscopic detorsion is advocated as the primary treatment choice, emergency surgery is required for patients who present with peritonitis, bowel gangrene, or perforation or for patients whose non-operative treatment is unsuccessful. Although emergency surgery includes various non-definitive or definitive procedures, resection with primary anastomosis is the most commonly recommended procedure. After a successful non-operative detorsion, elective sigmoid resection and anastomosis is recommended. The overall mortality is 10% to 50%, while the overall morbidity is 6% to 24%.

Evaluating anatomical research in surgery: a prospective comparison of cadaveric and living anatomical studies of the abdominal wall

BACKGROUND

Cadaveric research has widely influenced our understanding of clinical anatomy. However, while many soft-tissue structures remain quiescent after death, other tissues, such as viscera, undergo structural and functional changes that may influence their use in predicting living anatomy. In particular, our understanding of vascular anatomy has been based upon cadaveric studies, in which vascular tone and flow do not match the living situation.

METHODS

An angiographic analysis of the abdominal wall vasculature was performed using plain film and computed tomography angiography in 60 cadaveric hemi-abdominal walls (from 31 cadavers) and 140 living hemi-abdominal walls (in 70 patients). The deep inferior epigastric artery (DIEA) and all of its perforating branches larger than 0.5 mm were analysed for number, calibre and location.

RESULTS

Both large, named vessels and small calibre vessels show marked differences between living anatomy and cadaveric specimens. The DIEA was of larger diameter (4.2 mm versus 3.1 mm, P < 0.01) and had more detectable branches in the cadaveric specimens. Perforators were of greater calibre (diameter 1.5 mm versus 0.8 mm, P < 0.01) and were more plentiful (16 versus 6, P < 0.01) in cadaveric specimens. However, the location of individual vessels was similar.

CONCLUSIONS

Cadaveric anatomy displays marked differences to in vivo anatomy, with the absence of living vascular dynamics affecting vessel diameters in cadaveric specimens. Blood vessels are of greater measurable calibre in cadaveric specimens than in the living. Consequently, cadaveric anatomy should be interpreted with consideration of post-mortem changes, while living anatomical studies, particularly with the use of imaging technologies, should be embraced in anatomical research.

Sigmoid volvulus in the Middle East

Little is known about sigmoid volvulus in the Middle East despite textbooks referring to the region as part of the "volvulus belt." Our objectives were to assess the prevalence, clinical presentations, radiological findings, operative treatments, and postoperative outcomes of patients managed for sigmoid volvulus in Jordan as a model for the region. The medical records of patients with large bowel obstruction who were managed at King Abdullah University Hospital and its affiliated institutes, northern Jordan, over a 6-year period between January 2001 and January 2007 were retrospectively reviewed to identify patients with a confirmed diagnosis of sigmoid volvulus. Sigmoid volvulus was responsible for 9.2% of all cases of large bowel obstruction seen during the study period. There were 32 patients with sigmoid volvulus, 24 (75%) of whom were men. The median age of the patients was 59 years (range 21-83 years). Abdominal pain and distention were the main presentations. Colonoscopic detorsion was applied in 25 patients, which was achieved in 17 (68%) of them after the first attempt. Six patients had a gangrenous sigmoid colon, four of which required resection and a Hartmann procedure. Sigmoid resection with primary anastomosis was performed in 28 patients, including 2 with a gangrenous colon. Postoperative complications were observed in five patients, including one patient with viable colon who develop an anastomotic leak. Two patients died, making the mortality rate 6%. Sigmoid volvulus is uncommon in Jordan. Resection of the sigmoid colon with primary anastomosis appears to be the preferred procedure.

Intramucosal ganglion cells in normal adult colorectal mucosa

Intramucosal ganglion cells are incompletely understood. Reviewed were 100 normal specimens from colorectal biopsies of nonconstipated adults to firmly establish the existence of intramucosal ganglion cells in normal adult colorectal mucosa, determine whether intramucosal giant ganglia exist, and compare the prevalence of colorectal intramucosal ganglion cells between men and women. Fifty specimens from each gender were examined. Twenty specimens contained intramucosal ganglion cells, including 15 from women (75%) and only 5 from men (25%). Intramucosal ganglion cells occurred singly or in clusters. One woman had large disciform and globular clusters with 7 ganglion cells, resembling giant ganglia. Awareness of ganglion cells and large ganglia in normal mucosa is necessary to avoid potential confusion with ectopic ganglion cells and submucosal giant ganglia seen in adult intestinal neuronal dysplasia. Intramucosal ganglion cells in normal colorectal mucosa are particularly common in women. This disparity might contribute to colorectal neurophysiologic differences between genders.

Sigmoid volvulus an update

Sigmoid volvulus is the third most common cause of colonic obstruction in the United States after cancer and diverticulitis. Etiologic factors include anatomic variation, chronic constipation, neurologic disease, and megacolon. Management of sigmoid volvulus involves relief of obstruction and the prevention of recurrent attacks; the outcome depends on the population and selection of patients. Although volvulus is uncommon, it may be encountered during pregnancy and is a condition that poses significant risk to both mother and fetus requiring a management strategy that varies with each trimester.