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

Since it was first described by von Rokitansky in 1836 [1], sigmoid volvulus remains a major cause of colonic intestinal obstruction, which results from twisting of the sigmoid colon on its own mesentery [2]. Globally, sigmoid volvulus shows geographic variation being higher in developing countries than in developed world [2,4,7]. It accounts for 2% to 5% of colonic obstructions in Western countries and 20% to 50% of obstructions in Eastern Countries including Africa [4,7]. In this study, sigmoid volvulus accounted for 14.2% of all diagnosed intestinal obstruction seen during the study period in our setting. This concurs with figures of 14.1% that was reported by Jumbi and Kuremu [23] in Kenya. There is no satisfactory explanation for the geographical distribution. It has been suggested that high fiber diet may contribute to the high incidence in Africa where the high fiber results in heavy loading of the sigmoid colon [24,25]. In East Africa, sigmoid volvulus is the second most common cause of intestinal obstruction after adhesions [23].

Sigmoid volvulus has been reported to occur in all age groups, from neonates to elderly [25]. Most often this condition is observed in adults, but the age at which it is most common also varies geographically. In developing countries, a man aged between 40 and 60 years is usually reported, whereas in developed countries, the mean age is between 60 and 70 years [5,11]. As reported in other African studies [11,13,14,23], the median age of 48 years in this study was younger than the age described in most developed countries; about 10 years difference has been reported in these studies [14,23]. We could not establish the reason for this age differences.

The male predominance demonstrated in this study was in keeping with previous observations reported in studies performed elsewhere [11,13,14,19,23]. There is a marked over-all preponderance of male patients with sigmoid volvulus, with a reported ratio of 2.5-9.1 [21,26]. It is suggested that the more spacious female pelvic area allowed a greater possibility of spontaneous reduction of a beginning volvulus [27]. Another predisposing factor is the mesocolon, which is longer in men but wider in women [8]. Heavy loading is more likely to cause sigmoid volvulus in the presence of a longer mesentery.

In keeping with other studies performed in developing countries [14,23], the majority of patients in this series came from the rural areas located a considerable distance from the study area and more than eighty percent had either primary or no formal education. Most of these patients were unemployed and had no identifiable health insurance. This observation has an implication on accessibility to healthcare facilities and awareness of the disease.

Clinically, sigmoid volvulus may present acutely as an emergency or subacutely especially when it is with associated recurrent symptoms of constipation and distention. As reported by other authors in developing countries [13-15], more than ninety percent of patients in this study presented with acute bowel obstruction. In developing countries like ours where over 60% of the populace cannot afford hospital treatment, patients seek hospitalization only when they had developed irreversible intestinal obstruction [13-15]. This observation is reflected in our study where more than ninety percent of patients presented late with acute intestinal obstruction and bowel perforations. The higher incidence rate of delayed presentation in developing countries like Tanzania is best explained by the challenges in health-related transportations, ignorance, poverty and lack of medical awareness [13-15,23]. This delayed presentation increases morbidity and mortality many-folds, as is evident from our results. We could not establish the reasons for the late presentation in this study.

The clinical presentation of sigmoid volvulus in our patients is not different from those in other studies [3-5,11,14,23], with abdominal pain, constipation and abdominal distention being common to all the patients. In this study, the classic triad of abdominal pain, abdominal distention and constipation was reported in 93.2% of the patients.

The diagnosis of acute sigmoid volvulus is established by clinical and radiological findings. In the majority of patients, a thorough physical examination and abdominal radiographs are adequate to achieve the diagnosis. Typical symptoms include sudden abdominal pain and distension followed by constipation. The most common signs are abdominal tenderness and asymmetrical abdominal distention. Other findings include abnormal bowel sounds, abdominal tympany, a palpable abdominal mass, empty rectum, and dehydration [28]. Plain radiographs are diagnostic in 57%-90% of patients [29,30]. The classical sign of acute sigmoid volvulus is the coffee bean sign. Abdominal Computed Tomography (CT) usually reveals a dilated colon with an air/fluid level and the “whirl sign”, which represents twisted colon and mesentery [31]. The classical plain abdominal x-ray features of sigmoid volvulus in this study were demonstrated in more than three quarters of patients. Abdominal CT scan was performed in only 2.7% of cases due to its high cost and irregular availability of this facility at our centre.

Previous studies performed in developing countries showed that ileo-sigmoid knotting accounts for 15-17% of the cases of sigmoid volvulus [11,14,23]. This concurs with our study in which ileo-sigmoid knotting was reported in 16.4% of the patients.

The ileo-sigmoid knot is a rare but serious abdominal emergency in which the ileum and sigmoid entangle each other to form a knot, which may lead to vascular compromise and gangrene of both the ileum and sigmoid colon. The condition is serious, generally progressing rapidly to gangrene of both ileum and sigmoid colon. However, the accurate preoperative diagnosis of ileo-sigmoid knotting is difficult, particularly when abdominal CT is not used. The disease is generally misdiagnosed as an obstructive or non-obstructive emergency in the preoperative period and the correct diagnosis is made upon laparotomy or, in some cases, autopsy [14,19,32]. This observation is reflected in our study in which all patients with ileo-sigmoid knotting presented acutely and all except one were found to have gangrenous bowel. Therefore, awareness of the condition is essential, for prompt diagnosis and optimal management.

The treatment of sigmoid volvulus remains controversial, and depends on the selected procedure and the most appropriate therapeutic approach in terms of the clinical status of the patient, the location of the problem, the suspicion or presence of peritonitis, bowel viability and the experience of the surgical team [33].

Initial nonoperative management, that is, sigmoidoscopic decompression as advocated by Bruudsgaard [34], followed by semi-elective sigmoidectomy and primary anastomosis has been widely accepted as standard management [11,35]. The nonresectional procedures such as sigmoidopexy and mesosigmoidoplasty have no need for bowel preparation and have lower morbidity and mortality rates but have high incidence of recurrence [35]. Where the decompression fails and there are signs of colonic gangrene, sigmoid resection and Hartmann’s procedure or double barreled colostomy is done to avoid the high mortality associated with primary anastomosis in this situation [35,36]. Recently laparoscopic resection has been used in high-risk or elderly patients who may not tolerate conventional surgery [36]. A more critical appraisal is however needed for its general use. The treatment of choice at this time is resection with primary anastomosis in patients with viable sigmoid colons and Hartmann’s procedure in those with gangrenous bowel [37]. Recurrence of sigmoid volvulus among patients treated with nonoperative approach is a common happening which ought to influence the choice of procedure to be performed. Most of our patients are poor and cannot afford to come back for interval sigmoid colectomy once the volvulus is reduced at sigmoidoscopy. It is for this reason that there is a tendency to perform resection and primary anastomosis. Irrespective of the presentation the major determining factor for primary resection and anastomosis is the presence or absence of complication such as gangrene or perforation. Many authors now prefer one stage primary resection and anastomosis procedure and colostomy if there are complications [10,16,18]. Colostomy is often advised in cases where the gut is gangrenous [13-16]. In the present study, the majority of patients (69.9%) were treated with resection and primary anastomosis, of which 63.0% were emergency cases. Colostomy was offered to 30.1% of cases who had gangrenous and perforated bowel. This treatment modality agrees with what was demonstrated by Okello et al [14] in Uganda. In this study, we found no significant difference between cases treated by primary anastomosis (one-stage resection) and those treated by two-staged resection (colostomy).This finding was consistent with that reported by Akcan et al [16] and Okello et al [14], that there is often no significant statistical difference whether a patient is treated with primary resection anastomosis or colostomy in terms of morbidity, complications and mortality. However, we found no prospective randomized studies done to compare the outcome in primary anastomosis and two-stage resections. Our study has confirmed that, in the hands of competent and experienced surgeons, resection and primary anastomosis in sigmoid volvulus patients with viable bowel, is safe and does not necessarily result in increased risk or a longer hospital stay. When the bowel is gangrenous, it is safer to resect and leave a temporary colostomy. In cases of ileo-sigmoid knotting, the secret behind a successful outcome lies in early diagnosis and prompt and appropriate treatment.

The presence of complications has an impact on the final outcome of patients presenting with bowel obstruction due to sigmoid volvulus. In keeping with other studies [11,14,23], surgical site infection was the most common postoperative complications in the present study. In our series, the complication rate was significantly higher in emergency operations than in elective operation and in patients with gangrenous bowel undergoing bowel resection.

The median duration of hospital stay in our study was 12 days, which is higher than that reported in other studies [14,23]. The length of hospital stay was significantly longer in patients with advanced age, concomitant medical illness and presence of complications. However, due to the poor socio-economic conditions in Tanzania, the duration of inpatient stay for our patients may be longer than expected.

Overall, the mortality of sigmoid volvulus in our setting was 17.1%, a figure that is slightly higher than 15.9% and 15.8% reported by Okello et al [14] and Oren et al [18]. Many other authors have reported mortality rates within the same range [10,11,23]. The high mortality rate in our study may be attributed to advanced age, presence of concomitant medical illness, late presentation (≥24 hours), presence of shock on admission and presence of gangrenous bowels. Addressing these factors responsible for high mortality in our patients is mandatory to be able to reduce mortality associated with this disease.

A total of 80.2% of our patients recovered well and were discharged. This figure is comparable with 84.1% reported by Okello et al [14] in Uganda. However, in this study the follow-up of patients was generally poor as more than half of patients (survivors) were lost to follow-up by the end of study period. Self discharge by patient against medical advice is a recognized problem in our setting. Similarly, poor follow up visits after discharge from hospitals remain a cause for concern. These issues are often the results of poverty, long distance from the hospitals and ignorance. Delayed presentation, discharge against medical advice and the large number of loss to follow up were the major limitations in this study. The fact that this study included only patients who were evaluated and treated at a single institution, findings from this study may not reflect the whole population in this region. Also, the prevalent of HIV infection (which was not assessed) in our setting is still high and this might have contributed to high mortality among our patients. However, despite this limitation, the study has provided local data that can help healthcare providers in the management of patients with sigmoid volvulus. The challenges identified in the management of sigmoid volvulus in our setting need to be addressed in order to deliver optimal care for these patients.