Introduction

Colonic volvulus is one of the leading causes of large bowel obstruction worldwide, with the sigmoid colon accounting for about 60–75% of cases (1, 2). Sigmoid volvulus (SV) occurs when the sigmoid colon twists about its mesentery. In Western countries, SV accounts for about 10% of bowel obstruction (3). In contrast to Western countries, in endemic regions such as Africa and Asia, about 23–46% of intestinal obstructions are attributed to SV, with higher incidences reported in Western Africa (4-6).
In the “sigmoid belt” population, SV has a male preponderance and a younger age at presentation compared to the occidental population which presents as elderly with a mean age of 70 years (2, 7). SV generally presents with a constellation of nonspecific symptoms including abdominal pain, abdominal distension, constipation, and vomiting with variable timing (1, 8). Patients usually present within 3–7 days, and only 17% present within 48 h of onset (9). In the early phases of the disease, fever, tachycardia, hypotension, abdominal guarding, rigidity, and rebound tenderness are not present, but if they do appear, they are signs of perforation and/or peritonitis (9, 10).
In patients affected with SV without peritonitis or colonic gangrene, the preferred intervention is endoscopic detorsion in the acute phase, followed by elective surgery (1). Conservative management after endoscopic detorsion has been reported; however, this approach is associated with high rates of recurrence (43–75%) and mortality (15–40%) (1, 11-13). Emergency sigmoid resection with primary anastomosis (RPA) or Hartmann’s procedure (HP) remains the mainstay of treatment for patients with perforation, shock, and peritonitis (3).
The prognosis of patients affected by SV highly depends on factors such as a late presentation (>24 h), advanced age (>70 years), an American Society of Anesthesiologists (ASA) score >3, presence of severe comorbid illnesses, shock at admission, presence of bowel perforation, and peritoneal contamination (8). In sub-Saharan Africa, the mortality rates due to SV remain high, ranging between 15% and 17% (8, 14). Despite the younger age at diagnosis, factors such as poor access to surgical care, late presentation, delayed diagnosis, and interventions have been cited as potential causes of the high burden and mortality (14).
Although the incidence and burden of SV remain high in our environment (15), data remain limited regarding its surgical management and outcomes, particularly in a resource-constrained setting. We therefore carried out a study aiming to determine the clinical presentation, the operative management, and outcomes of SV at our facility.

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Materials and Methods

This was a retrospective audit that examined the medical records of patients in whom a diagnosis and management of SV was made. The period of study was between January 2015 and December 2023.
This research was conducted at the health records department of Kenyatta National Hospital a leading referral hospital in Nairobi that serves both East and Central Africa. Our facility has a bed capacity of 2400 attending to an annual number of approximately 949,000 inpatients. The hospital offers a wide variety of specialist and subspecialist services, and as such, there is a wide pool of patients and this will aid in yielding adequate data needed for the study. We included all patients aged ≥13 years within the study period, with a documented diagnosis of SV. We mainly excluded from this study patients who were operated on in different facilities and records with incomplete data.
The sample size was calculated using Cochran’s formula shown below:

n=(Z^2 Pq)/e^2 ,
where n is the population size, P is the reported mortality rate of SV in Malawi (6.9%) (16), q=1−P, e is the error margin (0.05), and Z is the statistic for the level of confidence [95% confidence interval (CI) with a Z value of 1.96].
Therefore,
n=((1.96)^2× 0.069× 0.931)/〖0.05〗^2 .
Hence, the desired sample was n=93 patients.
Subsequent to the ethical and scientific committee’s clearance (P586/07/2023), authorization was obtained from the hospital administration and the health records department to access the necessary files. The files were identified with the use of the International Classification of Diseases code for SV. The physical files were retrieved from storage, and relevant data were extracted. The collected data were cleaned, entered, coded, and analyzed using the Statistical Package for Social Sciences version 26.0 (SPSS 26.0; IBM, Chicago, IL, USA).
Data collected included patient’s demographics (age, sex), duration of symptoms, patient’s vitals at presentation (blood pressure, heart rate), laboratory values [full hemogram including white blood cell (WBC) and hemoglobin (Hb), urea, creatinine, and albumin levels)], imaging done, procedure done, and outcomes [length of hospital stay (LOS), anastomotic leak (AL), surgical site infection (SSI), mortality].
Categorical data were analyzed using frequencies and percentages, and continuous data were analyzed using means and standard deviations (SDs). Categorical data were compared using Fisher’s exact test, while continuous variables were compared using Student’s t-test. The relationship between each dependent and independent variable was evaluated using binary logistic regression, with a p value of <0.05 being indicative of a significant correlation. To ascertain statistical significance, factors were subsequently incorporated into multivariate analysis, with statistically significant variables identified at a p value of <0.2. Data presentation was done using tables of counts, pie charts, and bar charts.
 

Results

Demographic characteristics of patients diagnosed with SV
In total, 87 patients participated in the study over an 8-year duration. Seven patient files were excluded due to incomplete data. The minimum age was 14 years, while the maximum age was 92 years. The average age was 45.6 years (SD ±19.6). The results indicated that 87.5% (n=70) were male and 12.5% (n=10) were female.

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Clinical presentation of patients with SV
When examining the physical status classification system of ASA, 66% (n=53) were classified as ASA I. Thirty percent (n=24) were classified as ASA II, while 4% (n=3) were categorized as ASA III.
The findings showed that 39% (n=31) of the patients had underlying comorbidities. Hypertension was found in 42.4% (n=14) and diabetes mellitus in 18.2% (n=6) of patients, and these were the common underlying comorbidities identified among the patients, as shown in Table 1.
Most patients had abdominal pain and abdominal distension for 5.3 (SD ±3.4) days on average. Further, patients had vomiting for 4 days on average and fever for 5 days on average. The majority of patients who presented with abdominal pain and abdominal distension (67.5%, n=54) took between 3 and 6 days to seek care. The results also showed that the overall average time taken to seek care after the start of symptoms was 5.36 (±3.4) days.

 

Table 1.

Presence of comorbidities
ARDS, acute respiratory distress syndrome; COVID-19, coronavirus disease 2019; DM, diabetes mellitus; HTN, hypertension; RVD, right ventricular dysfunction.

Abdominal examinations indicated that the majority of patients, 90% (n=72), presented with abdominal distension, and 10% (n=8) had peritonitis. A rectal examination indicated that 95% (n=76) of the patients had empty vaults, while 5% (n=4) exhibited blood on the examining finger.

Laboratory investigations
The diagnostic evaluation of the patients with SV revealed that 60% (n=48) of the patients had a WBC count <11 x10^9/L and 8.8% (n=7) had low Hb levels, while 41.8% (n=33) of the patients had deranged creatinine levels.

Imaging modality
In investigating the imaging used, all the patients (100%) had an abdominal X-ray done, while 38.8% (n=31) of these patients additionally had a computed tomography (CT) scan examination done to confirm the diagnosis of SV. Typical findings on abdominal radiographs included multiple air/fluid levels and a dilated sigmoid colon with a coffee bean sign. The CT scan findings that confirmed SV included a dilated sigmoid colon and a whirlpool pattern in the mesentery.

Intraoperative findings
Intraoperative findings showed that 55% (n=44) had viable bowel and 45% (n=36) of the patients had gangrenous bowel.

Operative management
Surgical procedure
The majority of patients underwent RPA procedure (76.3%, n=61), while 23.8% (n=19) underwent HP.
The findings from Fisher’s exact test revealed that gender (p = 0.037), rectal examination findings (p = 0.040), and intraoperative findings (p = 0.001) were significantly associated with the procedure done (Table 2).

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Table 2.

Association between patient characteristics and the procedure done
ASA, American Society of Anesthesiologists; Hb, hemoglobin; SpO2, oxygen saturation; WBC, white blood cell.
 

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Multivariable analysis of factors associated with the surgical procedure done
Multivariable analysis was applied to variables with p ≤ 0.2 from the bivariate analysis, and the results showed that patients with gangrenous bowel were five times more likely to have HP’ than patients with viable bowel [adjusted odds ratio (aOR)=5.03, 95% CI: 1.34–18.91, p = 0.017], that patients with blood on the examining finger were nine times more likely to have HP’ (aOR=9.14, 95% CI: 1.72–16.33, p = 0.008), and that male patients were five times more likely to undergo the procedure than female patients (aOR=5.03, 95% CI: 1.05–23.49, p = 0.044).

Management outcomes
The analysis on LOS revealed that the mean LOS was 14 (SD ±8.7) days. The findings also showed that 91.3% (n=73) of the patients had hospital stays of >5 days.
In investigating the presence of complications, 72.5% (n=58) of the patients had at least one complication. The common complications included SSIs in 45% (n=36) and ALs in 15% (n=12), while mortality occurred in 12.5% (n=10).
There was no statistically significant association between the procedure done and complications identified. However, the SSI rate was higher among patients who underwent HP compared to RPA (47.4% vs. 44.3%). Mortality was higher among those who underwent HP compared to RPA (21.1% vs. 9.8%), as shown in Table 3.

 

Table 3.

Association between the procedure done and complications

The association between patient characteristics and complications was investigated. The findings showed that the presence of complications was higher among patients who had longer durations of vomiting prior to presenting to the facility [4.8 (SD ±3.2) days] compared to 3.6 (SD ±1.7) days in those without complications. WBC and intraoperative findings were also found to be significantly associated with the presence of complications, as shown in Table 4.

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Table 4.

Association between patient characteristics and complications
ASA, American Society of Anesthesiologists; Hb, hemoglobin; SD, standard deviation; WBC, white blood cell.
 

The findings established that an increase in the duration of vomiting by 1 day was associated with a 27% increase in the likelihood of complications (aOR=1.27, 95% CI: 1.08–4.466, p = 0.006). Those patients with gangrenous bowel were four times likely to have complications compared to those who had viable bowel (aOR=3.71, 95% CI: 1.22–11.31, p = 0.021), as shown in Table 5.

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Table 5.

Multivariable analysis of factors associated with management complications
aOR, adjusted odds ratio; CI, confidence interval; Ref, reference; WBC, white blood cell.

Association between the procedure done and complications among patients with gangrenous bowel
The findings established that the SSI rate was 46.7% among those with HP compared to RPA (28.6%). AL was significantly higher among patients with gangrenous bowel who underwent RPA compared to HP (28% vs 0%). Mortality occurred in patients with gangrenous bowel who underwent HP (13.3% vs. 0%) (Table 6).

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Table 6.

Association between the procedure done and complications among patients with gangrenous bowel
AL, anastomotic leak; HP, Hartmann’s procedure; RPA, resection with primary anastomosis; SSI, surgical site infection.

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Discussion

Our study revealed a predominance of male patients, with a mean age of 45.6 years and a male-to-female ratio of 7:1. These findings align with those documented within the sub-Saharan region (6, 8, 17). In endemic regions, SV primarily affects young adult males in their fourth and fifth decades of life (3, 6). These findings could mainly be attributed to the high-fiber diet in the African population, compounded by their relatively narrow pelvis and elongated sigmoid colon with a narrower mesentery (3, 6).
Global data indicate that elderly patients with SV frequently present with ASA scores ≥ 2, with most comorbidities being diabetes, hypertension, and neurological or psychiatric disorders (1, 18, 19). In the present study, the majority of patients exhibited pre-operative ASA scores of 1, with hypertension and diabetes being the most prevalent comorbidities. The severity of SV can vary widely among patients, influencing their ASA classification (8). As a result of such variability, the lower ASA scores and reduced incidence of systemic diseases in our study could be attributed to demographic factors such as younger age and integration of non-severe (viable bowel) cases of SV.
The average duration of symptoms was 5 days, with 69% of the patients presenting after 3–6 days since the start of symptoms and the duration ranging from 1 to 21 days. These findings align with those from Tunisia that established the mean duration of symptoms to be 4.2 days (20). The present study also concurs with other previous studies which revealed that vomiting is a late presentation and majorly presents within 3–7 days of onset of symptoms, with <17% of the patients presenting within 48 h of onset (8, 9). This gradual evolution of symptoms may contribute to a longer duration of presentation before seeking medical attention. The diagnostic accuracy of plain abdominal X-ray in this study was at 61.2%. These findings are in keeping with global trends and place the diagnostic accuracy of plain radiographs between 52% and 99% (21-23).
The present findings established that 45% of the SV patients had gangrenous bowel as an intraoperative finding. These findings are higher than the 25% and 35% reported in studies conducted in Kenya and Ethiopia, respectively (5, 15). Emergency surgery was the exclusive treatment provided to all 80 individuals diagnosed with SV. A greater majority (76%) had resection and anastomosis. Studies corroborating resection and anastomosis as the primary surgical intervention have been documented (15, 16). The elevated incidence of bowel gangrene and emergency surgical procedures could be ascribed to late presentation, delayed diagnosis, and the lack of endoscopic detorsion abilities.
The overall mortality from the study at 12.5% underscores the necessity of prompt intervention. Mortality was higher in patients with HP compared to RPA (21% vs. 9.8%) and more in those who underwent HP of gangrenous bowel. The findings are consistent with a study conducted in Kenya by Ooko and White, which reported a higher mortality rate in patients with gangrenous bowel in the HP group compared to the RPA group (22.7% vs. 8.3%) (15). Madiba and Thomson conducted a study in KwaZulu-Natal, reporting an overall mortality rate of 17%. Mortality rates among patients with gangrenous SV were similarly observed to be higher in those who underwent HP compared to RPA (22% vs. 18%) (24). Even though HP had poorer outcomes, several patient-related confounding factors not included and not analyzed in our study had the potential to increase the mortality rate, complication rate, hospital stay, and need for critical care in this specific subset of patients. Most of the patients had a longer duration of hospital stay, although there was no significant difference between those who underwent HP and RPA (24).
Our single-center retrospective cross-sectional analysis was biased and unable to control for confounding variables in identifying predictors of management and outcomes. As a result, we were unable to assess the risk factors associated with surgical management, which is crucial to treating these patients. The use of retrospective clinical records limited accurate and complete data collection. This study concentrated on in-hospital complications; therefore, long-term complications were not evaluated. In spite of the limitations, this study has provided local data that will be useful in decision-making when managing patients with SV. A multi-centered prospective cohort study is recommended in this field.

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Conclusion

SV predominantly affects middle-aged adults. In the absence of endoscopic detorsion, RPA remains the primary treatment for patients with viable bowel. HP had an overall higher mortality compared to RPA.

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Author contributions

KAMM led in conceptualization, data curation, formal analysis, methodology and in writing, reviewing & editing of the original draft. ENO and DO led in supervision. ES equally supported.

 

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