Ileo-sigmoid knotting: a review of 61 cases in Kenya

Introduction Ileo-sigmoid knotting (ISK) is a rare cause of bowel obstruction in which the ileum twists around the sigmoid colon. It is associated with rapid bowel gangrene and a high mortality rate. Little has been published about this condition in Kenya. The objective was to determine the presentation, management, and outcome of patients with ISK. Methods A seven year (January 2008-December 2014) retrospective chart review of patients managed for ISK at Tenwek Hospital in Bomet, Kenya. Results A total of 61 cases were identified, with a mean age of 35.8 years (range 2-68), and mean symptom duration of 1.6 days (range 3 hours-7 days). Gangrene was noted to involve both the ileum and colon in 45 patients, the ileum only in 9 patients, and the sigmoid colon only in one. Resection and primary anastomosis was carried out in most cases of gangrenous ileum (48/54, 89%) and gangrenous sigmoid colon (34/46, 74%), while resection and stoma was performed in 8 patients with gangrenous colon. Death occurred in 7 (11.5%) patients due to severe sepsis and multisystem organ failure. Morbidities were noted in 15 (24.6%) patients, including surgical site infection (8, 13.1%), respiratory insufficiency (4, 6.6%), fascial dehiscence (3, 4.9%) and anastomotic leak (2, 3.2%). The mean duration of hospitalization was 8.3 days (range 1-26). Conclusion In this review, though retrospective in nature, ISK was noted to have high rates of bowel gangrene. In the appropriate setting, resection and primary anastomosis can be safely carried out in most cases of gangrenous colon.


Introduction
Ileo-sigmoid knotting (ISK) is a rare cause of acute intestinal obstruction [1][2][3] that occurs when a loop of ileum wraps around the base of a redundant sigmoid colon [3][4][5]. This condition is associated with high rates of gangrene involving the ileum, sigmoid colon, and at times, even extending to the caecum and ascending colon [3,5]. Anatomical factors postulated to predispose to the development of ISK include: a long small bowel mesentery and freely mobile small bowel, and a redundant sigmoid colon on a narrow mesenteric base [2,5]. Though early surgery is recommended, as ISK is associated with early bowel gangrene and a high mortality rate, most cases are diagnosed intra-operatively due to the rarity of this condition and nonspecific clinical, laboratory, and X-ray features [1,3]. Use of Computerized tomography (CT) has led to an increased preoperative diagnostic accuracy, but is most useful when diagnosis is in doubt [6,7]. The purpose of this study was to review the presentation, management, and outcome of patients with ISK.

Results
Sixty one cases of ISK were noted, representing 38% of the 159 cases of sigmoid volvulus seen during the study period. The group was comprised of 51 (83.6%) males and 10 (16.4%) females and had a mean age of 35.8 years (range 2-68). Peak incidence of ISK was noted in the 31-40 years age group, and the majority of cases (70.5%) between 11-50 years of age (Table 1) after resection of the gangrenous bowel, most had a double anastomosis, with only two cases having a colostomy and ileo-ileal anastomosis. The second look laparotomy was due to persistent intraoperative hypotension (7, 33.3%), to assess small bowel viability (6, 28.6%) and unclear or not indicated in seven cases.
Significant delays from admission to operation were noted in 9 patients who presented with minimal tenderness, no guarding or rigidity, blood pressure readings within normal range and nonspecific findings on X-ray, in whom a diagnosis of acute abdominal emergency was not made. A notable example is a 45 year old male patient who presented with 6 days history of abdominal pain, vomiting and constipation, with findings of epigastric tenderness on examination, vital signs within normal and elevated amylase at four times normal range, who was managed as acute pancreatitis, only to deteriorate within 48 hours of admission.
At laparotomy, he was found to have necrotic ileum and sigmoid colon, and died within 24 hours after damage control surgery. The mean length of hospitalization was 8.3 days (range 1-26) with 49% being admitted for a period of 7-9 days.

Discussion
ISK is an important cause of intestinal obstruction (IO), with a varied geographical distribution. It is a common cause of IO in certain African, Asian and Middle Eastern countries, where it may account for up to half of all cases of sigmoid volvulus (SV) [3,5,8,9].
Thus early diagnosis and operative treatment are vital in the reversal of the effects of endotoxemia from gangrenous bowel and the prevention of vascular compromise in those with viable bowel at presentation [3,5,10,12]. This condition has been reported to have a male predominance [2,3,13], peak incidence at 30-45 years [3,8], and a mean age of 40-49 years [2,5,8,9,13]. Similar findings were noted in this series except for the slightly lower mean age of vomiting (84-89%) [5,[8][9][10][11]14]. Peritonitis has been noted in 37-69% of cases [5,10,11,14]. The most common features noted on Xray include distended loops of small bowel with multiple air fluid levels and distended colon [10][11][12][13]. Some X-rays may show apparent SV only, free air due to perforation or may be normal [9,11]. Due to the nonspecific nature of the presentation, findings and plain X-ray features, the preoperative diagnostic accuracy has been reported to 0-25% [8,9,15]. In this series, the symptoms, signs, X-ray features, and preoperative diagnostic accuracy were similar to those of other studies. A clinical picture of small bowel obstruction, radiographic evidence of large bowel obstruction and inability to insert an endoscope have been proposed as a useful diagnostic triad of ISK [12,16]. Use of a rigid sigmoidoscope in this series may have contributed to an inconclusive diagnosis in the three patients due to inability to reach the point of torsion. It is also important to note that this triad was applicable in a small proportion of our patients who did not have peritonitis or in septic shock. Some authors argue that a preoperative diagnosis of ISK is not important, but paramount is to operate as soon as a reasonable diagnosis is made [9]. This may be readily applicable in patients presenting with symptoms of IO and peritonitis, septic shock, or those with a pneumoperitonium on X-ray. Patients with ISK who present with minimal tenderness and nonspecific features on plain X-ray and laboratory findings within the normal range, may have significant diagnostic delay, as was noted in 9 patients in this series. A CT scan may be useful in this subset of patients [7,12].
Management should begin at presentation with aggressive fluid resuscitation and correction of electrolyte and acid-base imbalances where present [2,7,12,13]. Empiric antibiotic therapy should be commenced early due to the high incidence of bowel gangrene and associated bacterial translocation, and continued after the operation especially in gangrenous bowel [2,7,13]. The operative procedure undertaken should be based on the degree of physiological disturbance, operative risk assessment and intraoperative findings [2,5,12]. Patients who are unstable as defined by a blood pressure <90/60 mm Hg and a pulse >120 beats/min, either preoperatively, the viability of the segments is questionable [5,12,16]. In presence of frankly gangrenous bowel or septic shock, enblock resection is advised due to risk of significant increase in the duration of procedure, rupture of the distended bowel segments, and/or release of toxins from the untwisted segment of bowel [2,5,12]. In this series, detortion was performed in clearly viable bowel, while in gangrenous cases, the sigmoid was resected first, allowing the ileum to be easily detorsed and the nonviable edges resected. This was to spare as much small bowel as possible to reduce the probability of having short gut syndrome [5]. Traditionally, resection with colostomy has been advocated for management of gangrenous sigmoid due to poor vascularity and risk of anastomotic leak [7,13,16].
Newer studies have indicated that primary anastomosis in gangrenous sigmoid colon can be safely carried out without significant complications [2,5,12]. A resection and anastomosis (RA) was carried out successfully in 74% of the patients with gangrenous sigmoid volvulus in this series with an anastomotic leak noted in only one patient (2.9%, n=34). Patients had a RA of gangrenous sigmoid in the initial or at the second look laparotomy if they were healthy, had no gross contamination, and the bowel edges looked viable, with a rich blood supply, and a tension free anastomosis could be achieved. However, a stoma should be used in cases where there is limited or little expertise, the viability of the stump is doubtful, and there is a significant difference in diameter of the bowel edges [9,10,14]. Resection and primary anastomosis of a viable sigmoid has also been advocated due to risk of recurrence of the volvulus by the redundant loop [2,5,12]. Resection is usually limited to the redundant and freely mobile segment of the sigmoid colon that has cause the torsion except in cases of megacolon [5].
This was carried out in most cases in this series with viable sigmoid colon. Management for the ileum includes operative detortion if viable and resection with primary anastomosis if gangrenous [2,6,12]. The mortality rate for ISK has been reported to be as variable as 16-44% [1, 2, 5, 9-11, 14, 17]. The slightly lower mortality rate may have been secondary to the use of critical care adjuncts in this series. Older age (>60 years), presence of gangrenous bowel, and delayed presentation have been noted as factors related to higher mortality [5,10].

Acknowledgments
We are thankful for Tenwek Hospital administration for allowing us to undertake this study, and grateful to Dr. Heath Many for his wonderful insight during the preparation of the manuscript.