Magnitude and Clinical characteristics of Sigmoid Volvulus

Background: Sigmoid volvulus is a major cause of mechanical large bowel obstruction in volvulus belt countries. The objective of this study to explore the magnitude and clinical characteristics of Sigmoid Volvulus Methods: Hospital-based retrospective cross-sectional study employed in Debre Tabor general hospital Northcentral Ethiopia. A medical review conducted on the medical chart from Jan1, 2016 to Dec31, 2019. The collected data checked manually for completeness and consistency. The nal data coded and entered to SPSS version 23 for data processing and analysis. Binary logistic regression used to measure the association of each covariate with the outcome variable. In addition, factors that have p=0.25 with the outcome variables were taken into a multivariable logistic regression analysis to control the potential confounders. The result of the nal model expressed in terms of adjusted Odd Ratios (AOR) and 95% CI and statistical signicance declared if the P-value is less than 0.05. Result: There were 124 patients with sigmoid volvulus admitted within four years of the study. During the study period, 408 patients with bowel obstructions were admitted, among Mechanical large bowel obstruction (MLBO) 135 (33.1%), Mechanical small bowel obstruction (MSBO) 251(61.5%), and Ileosigmoid knotting 22(5.4%). Our study showed that sigmoid volvulus accounted for 91.9% and 30.4% of Mechanical Large bowel obstruction and Bowel obstruction respectively. Most of the patients were male 97.6 %( N=121) and rural residents 91.1 %( N=113). The peak age was 56-65 years accounted for 29 % and 65.3 %( N=81) of patients were above age 50years. The age ranged from 19-88 years. The mean and median ages were 56.52± (SD=14.4) and 58.5± (IQR=17.75) respectively. The mean of hospital stay for elective admission was 10.98(SD±4.33) days and the median was 11 (IQR±5) days. The mean of hospital stay for emergency admission excluding death and leave against medical advice was and median 8 (IQR±2)


Background
The word "volvulus" derived from the Latin "volvere or twist" [1].Sigmoid volvulus is the abnormal twisting of the bowel loop around the axis of its own mesentery more than 1800 [2]. The name of the sigmoid volvulus was given for the rst time by Von Rokitansky in 1836 [3]. Sigmoid volvulus is the most common anatomical site of colonic volvulus which is accounting for 60-75% of all cases [4]. The incidence of sigmoid volvulus is unknown worldwide but it varies widely accordingly to population and geography [5]. Sigmoid volvulus has multifactorial predisposing factors [3]. Anatomical factors include long loop and narrow base attachment to pelvic mesocolon, overload colon, advanced age, higher ber diet, neurologic or psychiatry disease, chronic constipation, and previous surgery [4,[6][7]. Sigmoid volvulus has been contributed to a low portion of large bowel obstruction in developed countries. It is the third cause of large bowel obstruction in the USA (accounting only 4%) following colorectal cancer and diverticular disease [8]. The prevalence of sigmoid volvulus is higher in volvulus belt countries which are extending from South Asia, Africa, and South America [5]. It is accounting for 50-85% of large bowel obstruction in Volvulus Belt countries [5]. Imaging ndings from Plain x-rays and Gastrogra n enema helps to differentiated sigmoid volvulus from cecal and transverse colon volvulus. Sigmoid volvulus produces a typical sign of bent inner tube or coffee appearance in plain abdominal X-ray. Gastrogra n enema shows a narrowing at the site of the volvulus and a pathognomonic bird's beak [8,9] Methods Study area and period The study conducted in Debre Tabor General Hospital Northcentral Ethiopia. Debre Tabor General Hospital is one of the oldest public hospitals in the country. Geographically, it is located in Debre Tabor city, South Gondar, Amhara regional state, North West Ethiopia which is 666km and 103 km from Addis Abeba and Bahir Dar respectively. It provides service for approximately 900 inpatient and 80,000 outpatients in a year that comes from the catchment area of the population around 3.5 million. Data collected from January 1, 2016 -December 31, 2019.

Study Design
A hospital-based retrospective cross-sectional study conducted in Debre Tabor General Hospital in all patients that presented with clinical or/ and radiological sigmoid volvulus January 1, 2016 -December 31, 2019. Parameters included demography, clinical presentation, and duration of illness, diagnosis, causes, procedures and intraoperative nding, postoperative complications, and management outcome. All patients from age 15 years and above with clinical or/and radiological diagnosis of sigmoid volvulus which managed with conservatively and /or operatively or died due to con rmed sigmoid volvulus was included while paralytic Ileus (functional obstruction) and age below 15 years and incomplete data were excluded from the study Data collection and analysis All daily medical records of patients' progress note, radiology report, operation note, pathology reports reviewed. The Medical data was ICD-10 Code K56.2 (Strangulation, Torsion, and Twist of colon or large intestine volvulus) and Data collected with a structured questionnaire that is developed by the English language and contains information about demography, clinical presentation and duration of illness, causes, diagnosis, intraoperative nding, procedures, postop complications, and outcome of bowel obstruction. The collected data checked for any inconsistency, code, and enter SPSS version 23 for data processing and analysis.
Normal distribution was evaluated with the Q-Q plot test and histogram diagram. Quantitative values were represented as mean ± standard deviation for normal distribution and Median ± Interquartile range for skewed data. Binary logistic regression used to measure the association of each covariate with the outcome variable. In addition, factors that have p=0.25 with the outcome variables were taken into a multivariable logistic regression analysis to control the potential confounders. The result of the nal model expressed in terms of Adjusted Odd Ratios (AOR) and 95% CI and statistical signi cance declared if the P-value is less than 0.05.

Ethical consideration
Ethical clearance obtained from the Ethical Review Committee of Debretabor University and collection started after approval of the proposal. The con dentiality and privacy of patients maintained during data collection. The data collected retrospectively from medical chart and consent from patients is not needed.

Results
There were 124 patients with sigmoid volvulus admitted within four years of the study. During the study period, 408 patients with bowel obstructions were admitted, among mechanical large bowel obstruction (MLBO) 135 (33.1%), mechanical small bowel obstruction (MSBO) 251(61.5%) and Ileosigmoid knotting 22(5.4%). Our study showed that sigmoid volvulus accounted for 91.9% and 30.4% of Mechanical Large bowel obstruction and Bowel obstruction respectively. Almost all patients were ASA I and only one (0.008%) patient had stage II hypertension as comorbidity (ASAII). Most of the patients were male 97.6 %( N=121) and rural residents 91.1 %( N=113). The peak age was 56-65 years accounted for 29 % and 65.3 %( N=81) of patients were above age 50years. The age ranged from 19-88 years. The mean and median ages were 57± (SD=14.4) and 59± (IQR=17.75) respectively (Table 1) The mean of hospital stay for elective admission was 10.98(SD±4.33) days and the median was 11 (IQR±5) days. The mean of hospital stay for emergency admission excluding death and leave against medical advice was 8.4(SD±4.1) days and median was 8 (IQR±2) days The clinical presentations were abdominal pain 100%, constipation 97.6%, abdominal distention, and 85.5%. The most prominent clinical ndings were abdominal tenderness 91.9% and visible peristalses 67.7%. Our study found that 66.9% was simple sigmoid volvulus and 33.1% was gangrenous sigmoid volvulus. Primary resection and anastomosis was the most common procedure for sigmoid volvulus for 77.4 %( N=96) and resection and stomas 13.4 %( N=17) .Mortality and morbidity rate of sigmoid volvulus in our study were 6.45% and 13.7% respectively (Table 2& 3).
Bivariable logistic cross tabulation analysis showed that mortality rate more common in men 6.6% vs.

Discussion
Sigmoid has been contributed to a signi cant burden on emergency surgical admission in volvulus belt countries. However, it is uncommon to cause of bowel obstruction in the USA [8]. The prevalence of sigmoid volvulus represented 4% in the USA [8], 9.2% in Jordan [5], and 40% in India [11]. Our study showed that sigmoid volvulus accounted for 91.9% and 30.4% of mechanical large bowel obstruction and bowel obstruction respectively. Similar ndings noted that sigmoid volvulus accounted for 58.6-73% in Ethiopia [2,10] and 76% in Iran [16] for large bowel obstruction. The exact etiology of sigmoid volvulus is unknown but different research noted that possible cause will be anatomical factors include long loop and narrow base attachment to pelvic mesocolon, overload colon, advanced age, higher ber diet and chronic constipation [4,[6][7].
The prevalence of sigmoid volvulus occurred more in male; our nding was 40.3:1 which was very high male dominance with compared in the previous nding noted in different studies done in Turkey 5.6:1, West Africa 14.3:1, Ethiopia 4.7-13.5:1, Uganda 5.25:1, Iran 5.25:1, Pakistan 11.5:1 and India 3.5:1 [2-3, 10-14,16]. The exact cause of sex discrepancy is not well-illustrated but possible reasons suggested that spacious female pelvic area allowed a greater possibility of spontaneous reduction of volvulus and wider mesocolon in females [3].
Sigmoid volvulus occurred at a young age in developing counties but it is more common in elder age in developed countries. The mean age of sigmoid volvulus in our study found 57± (SD=14.4). The Mean age of sigmoid in the different study estimated in Turkey 60.61± (SD=14.81) [3], in Ethiopia 69years [2], in Pakistan 60years [12] and in Uganda 52.2± (SD=15.98) [14]. The Mean age is between 60-70 years in developed countries [3]. The most clinical presentations were abdominal pain constipation and abdominal distention. The most prominent clinical ndings were abdominal tenderness and visible peristalses. Sigmoid volvulus has a signi cant role in morbidity and mortality especially when the obstructed bowel becomes gangrenous [2]. We found a high prevalence of gangrenous sigmoid volvulus (33.1%), this may due to the majority of our patients were rural residents (91. %). Another study done in Ethiopia noted that 26% of patients were gangrenous sigmoid volvulus [2]. The different options of treatment modalities were employed for sigmoid volvulus. Accordingly, research conducted in Ethiopia, Uganda and Pakistan, the primary resection and anastomosis was the most common mode of treatment for 78%, 75%, and 52-100% of their patients respectively [2,12,[14][15]. In our research, 77.4% of patients were managed with primary resection and anastomosis which was comparable with previous studies.
The mortality rate of sigmoid volvulus was varied from country to country. Accordingly, research reported in Ethiopia, Uganda, and Pakistan, the mortality rates were 4.5%, 15.9% and 8% respectively [2,12,14]. We found that the mortality rate was 6.45% which was comparable with previous studies in Ethiopia and Pakistan [2,12] and two times lowed in Uganda [14]. The mortality rate had statistical signi cance with bowel viability and hospital stay.

Conclusion
The prevalence of sigmoid volvulus was 91.9% and 30.4% of mechanical large bowel obstruction and bowel obstruction respectively. The males were forty fold affected in sigmoid volvulus than females.
Primary resection and anastomosis was the common procedure for management of sigmoid volvulus. Overall mortality rate was 6.45% and higher in gangrenous sigmoid volvulus ( Figure 1 Management algorithm of sigmoid volvulus in Debre Tabor Hospital, Northcentral Ethiopia, 2020