The role of sigmoidoscopy in thediagnosis and treatment of sigmoid volvulus

Sigmoid volvulus (SV) is a rare form of acute intestinal obstruction in which the sigmoid colon wraps around itself. The disease generally presents as a mechanical bowel obstruction with clinical features that are not pathognomonic. Similarly, X-ray films are not diagnostic in most cases. It is difficult to establish the correct preoperative diagnosis when CT and MRI are not used. The principal strategy in the treatment of SV in uncomplicated patients is emergency endoscopic detorsion followed by elective surgery; emergent surgery is required in patients with bowel gangrene, bowel perforation, peritonitis, or unsuccessful endoscopic treatment. In this review, we have discussed the role of sigmoidoscopy in the diagnosis and treatment of SV. Additionally, we have retrospectively and prospectively evaluated our 49-year, 987-patient clinical experience, the largest single-center SV series ever reported.


SIGMOIDOSCOPY IN SPECIAL SITUATIONS
Sigmoidoscopy in Childhood: SV is extremely rare in childhood, with less than 100 cases reported in the literature. 1,3,13,18,32,36,37 In spite of the fulminant clinical presentation, it is difficult to obtain a preoperative accurate diagnosis. 36,37 Although hydrostatic reduction via barium, water-soluble contrast, or saline was previously used during non-operative treatment, endoscopic reduction performed via pediatric endoscopes may also be used successfully in uncomplicated patients. 1,18,36,37 The morbidity of SV in childhood remains high Sabri Selcuk Atamanalp et al.  and occurs in approximately 30% of all patients; the mortality is also startling, which is observed more than 25% of patients. 18,36,37 Sigmoidoscopy in the elderly: SV is common in the elderly and approximately 50% of SV patients are over 60 years old. 1,5,13,15,21,38 Abnormal defecation and chronic constipation, which are features normally found in the elderly, may cloud the clinical picture. The clinical picture in these patients may therefore be less diagnostic. 1,3,5,13,15,21,38 Endoscopic reduction is the first choice in the treatment of uncomplicated patients, and the avoidance of emergency surgery improves the prognosis. 1,5 These elderly patients suffer from high morbidity, which occurs in 6-24% of cases. Notably, the mortality increases to 75% after the age of 70; 50-85% of these patients have serious comorbidities. 1,5,15,21,38 Sigmoidoscopy during Pregnancy: SV is relatively rare in pregnancy. As of 2014, there were fewer than 100 cases reported in the literature. 1,3,13,39,40 Abdominal pain, nausea, and vomiting are normal findings in pregnancy; as such, these clinical findings are not reliable diagnostic features of SV. 1,3,39,40 The management of SV in pregnancy requires a multidisciplinary approach involving general surgery, obstetrics, and neonatology. 39,40 Although endoscopic detorsion was thought to be unsuccessful in most pregnant patients in the past due to an enlarged uterus as a mechanical impediment, 40 gentle flexible endoscopic detorsion under careful monitoring is recommended as treatment of choice in all trimesters of pregnancy in the treatment of uncomplicated patients, but is particularly true for those women in the first and second trimesters. 39 SV has a poor prognosis in pregnancy, with reported 6-60% maternal and 20-50% fetal mortality rates. 1,39,40 Clinical Experience: The incidence of SV is high in Turkey, particularly in Eastern Anatolia 3,13 where our university clinic is located. To the best of our knowledge, this report represents the largest singlecenter SV series. A total of 987 patients with SV were treated over a 49-year period between June 1966 and June 2015 in the Department of General Surgery, Faculty of Medicine, Ataturk University. The data were collected retrospectively till 1986, and prospectively after. After resuscitation and clinical examination, abdominal X-rays were obtained for all patients (although CTs or MRIs have been obtained in several stable patients in recent years). Emergency surgery was performed in patients with acute abdominal findings, melanotic stool, and unsuccessful non-operative detorsion. Sigmoidoscopy was used in the diagnosis of sev-eral stable patients but has been used in the treatment of all stable SV patients. We used rigid sigmoidoscopy in the early years but have tended to use flexible sigmoidoscopy or colonoscopy over the past 26 years. In successfully detorsioned patients, a rectal tube was inserted into the sigmoid colon and was left in place for 12-24 hours. Elective surgery was recommended in several stable patients.
Diagnostic sigmoidoscopy was used in 151 patients; the correct diagnosis was obtained in 149 of those patients (accuracy rate, 98.7%). Endoscopic misdiagnosis included colonic invagination in one patient and partial colonic volvulus in another; notably, there were colonic malignancies in both patients. Nonoperative therapeutic procedures were used in 712 patients; barium enema in 13 patients, rigid sigmoidoscopy in 351 patients, and flexible sigmoidoscopy in 348 patients. The results of these procedures are shown in table 2. When the patients with bowel gangrene are excluded, the therapeutic success rate of then on operative procedures is 82.1%, with a highest success rate in the flexible sigmoidoscopy group (82.9%). In the nonoperatively treated group, 5 patients (0.7%) died: 3 died from toxic shock and two died from peritonitis; the lowest mortality rate was in the flexible sigmoidoscopy group (0.3%). Complications were observed in 17 of the nonoperatively treated patients (2.4%). These complications included renal insufficiency in 13 patients, myocardial infarction in two patients, and peritonitis in 2 patients, with the lowest morbidity rate in the flexible sigmoidoscopy group (1.4%). Early recurrence was observed in 26 patients (4.7%) with the lowest early recurrence rate in the rigid sigmoidoscopy group (3.3%).

DISCUSSION
As regards the diagnosis of SV, clinical features are not pathognomonic, and abdominal X-ray films are usually not helpful. However, CT and MR are almost always diagnostic. Rigid or (preferably) flexible sigmoidoscopy helps to the diagnosis of SV by direct visualization of the obstructive bowel lumen. Additionally, sigmoidoscopy may demonstrate the viability of the bowel mucosa and identify other potential causes of bowel obstruction.
Spontaneous detorsion of SV is not common and therefore requires emergency treatment. Rigid or (preferably) flexible endoscopic detorsion is the initial treatment of choice in SV in the absence of bowel gangrene, bowel perforation, or peritonitis. Hydrostatic reduction has historical value, and endoscopic detorsion via pediatric endoscopes is the preferable treatment method in children. Endoscopic reduction is the treatment of choice in the elderly, improving the overall prognosis by avoiding emergent surgery. Endoscopic detorsion via monitorization is also the first choice in pregnancy, particularly in the first and second trimesters.
There is minimal morbidity and mortality from flexible sigmoidoscopy-treated SV. Because SV has a tendency to recur and because each subsequent SV episode has different morbidity and mortality, elective surgery is recommended in a select group of patients.