INTRODUCTION
Volvulus results from torsion of the bowel around the axis of its mesentery, causing bowel obstruction and ischemia. It most often occurs at the sigmoid colon and caecum, and volvulus accounts for 5% of bowel obstructions in developed countries. Small bowel volvulus is an extremely rare complication, with a reported incidence of 1 to 5 cases per 100,000 in the developed world [
1–
3].
Ileostomy formation is a common intervention in elective and emergency settings, and the resulting stoma may be permanent or temporary. Currently, 120,000 ileostomies and colostomies are performed annually in the United States, carrying significant morbidity and altering patients’ quality of life. Harris et al. [
4] found the most common stoma-related complications were herniation, necrosis, prolapse, stenosis, fistula, and small bowel obstruction (SBO). SBO following an ileostomy is usually the result of postoperative adhesions within the abdomen or pelvis, or at the site of ileostomy. A complication of stoma formation is stoma outlet obstruction (SOO), which occurs just below the site of the stoma. SOO may be caused by ileostomy volvulus; however, volvulus in the absence of adhesions following ileostomy formation is extremely rare.
Ulcerative colitis (UC) is a chronic inflammatory bowel disease, and stoma formation is required in 4% of UC patients within 5 years of diagnosis [
2,
5]. This case report presents a 44-year-old woman with UC who had a recent ileostomy complicated by SBO secondary to volvulus with no adhesion formation. We also conducted a systematic literature review to investigate the causes, diagnosis, treatment, and preventative measures of ileostomy-related SBO.
DISCUSSION
The current study documents an unusual case of SBO following ileostomy volvulus and a systematic literature review. This review evaluated previous studies reporting volvulus as a cause of SBO in ostomy patients and found that the most common causes of ileostomy were colorectal cancer or UC, with abdominal CT being the most common diagnostic tool. Most patients had loop ostomies, and the second most common ostomy was endostomy. Only 13 individuals reported a recurrence of volvulus, and no mortality was reported during follow-up. Overall, the case reported herein is unusual, and ileostomy volvulus without the presence of adhesions has never been reported previously.
Normally, volvulus accounts for 2% of SBO; however, volvulus in the absence of adhesions in an ostomy patient has seldom been reported [
14]. This may be due to difficulty in identifying and diagnosing ileostomy volvulus, as its etiology can be easily misattributed to subfascial adhesions. The patient documented in this case report presented to the emergency department with worsening abdominal pain, feculent vomiting, high stoma output, absent bowel sounds, and hemodynamic instability: this is congruent with the presentations described in the studies included in this systematic literature review, as well as current guidelines for clinically diagnosing obstruction in ostomy patients [
15]. Features that would differentiate volvulus from other causes of SBO include the inability to easily insert a digit or NGT through the stoma, although this may also be present in stomal luminal stenosis. Considering that SBO as a complication of stomas is relatively common (4.6%–27.3%) and emergent management is needed to prevent gangrenous bowel resection and long-term morbidity, volvulus in ostomy patients should still be considered in the absence of adhesions [
2,
16]. Inconsistencies in the definition of SOO within studies may also have limited their reporting. For example, Ohira et al. [
12] defined outlet obstruction as intestinal obstruction after ileostomy with the part penetrating the abdominal wall, while Kitahara et al. [
13] defined it as SBO symptoms with CT showing intestinal dilatation just below the penetrating part of the stoma site. These inconsistencies should be noted and unified in future studies.
Adhesions account for approximately 70% of SBO in adults, with up to 25% of patients who underwent abdominal-pelvic surgery subsequently developing adhesions. These are also the main cause of SOO [
12,
17]. While laparoscopic surgery reduces the incidence and severity of adhesions compared to laparotomies, previous studies have commented that the absence of a fixation point in laparoscopic procedures would allow additional room for further twisting at the ileostomy site, increasing the risk of ileostomy volvulus [
18]. Previous studies have also suggested loop stoma formation as a primary cause of SOO, identifying it as an independent risk factor compared to end ileostomy [
10,
12]. Despite this risk, loop ileostomy also avoids life-threatening complications, such as the consequences of anastomotic leaks and perforation, and so should still be considered a viable ostomy option.
The definitive cause of volvulus in ileostomy patients is an ongoing debate, and etiologies aside from adhesions have been previously considered. Uchino et al. [
19] reported cross incision of the rectus abdominis muscle sheath as a risk factor for torsion of the mesentery, while Ohira et al. [
12] and Kanazawa et al. [
20] stated that rectus abdominis muscle thickness ≥ 10 mm on CT was associated with a higher rate obstruction, but that difference was not statistically significant [
21]. A study by Kameyama et al. [
10] also stated the thickness of the rectus abdominis muscle may be a risk factor for obstruction due to increased resistance of stoma output, with Kitahara et al. [
13] reporting that the rectus abdominis was significantly thicker in patients who experienced recurrent SOO. Preoperative steroid dosing, high stoma output, and the presence of malignant tumors were also noted by studies as potential risk factors. Kitahara et al. [
13] reported an association between a lowered corticosteroid dose a month prior to surgery and an increased risk of SOO, but this is also a common guideline for medically refractory UC preoperatively and may simply reflect the risk of patients with worsening UC [
22]. Nonetheless, Kameyama et al. [
10] found that the perioperative steroid dose did not affect SBO incidence. Otherwise, Kitahara et al. [
13] noted high stoma output as a risk factor; if concomitant with intravascular depletion, this causes edematous small intestinal mucosa that is predisposed to obstruction. Neoplasms of the small intestine are also considered potential risk factors, as the associated poor systemic well-being and malnutrition increases the risk of SBO [
23]. Although these factors are largely unpreventable, the orientation and fixation of ileostomy can assist in preventing obstructions. Lee et al. [
11] and Anderson et al. [
9] emphasize the tendency of ileostomy to twist on its axis and form an obstruction. Antimesenteric fixation for the widening of adjacent ileal loops may be considered for correcting ileostomy orientation and reducing risk of SOO.
The main treatment options for SOO identified in the literature are conservative and surgical management. Conservative management largely involves the insertion of an NGT or transstomal decompression tube, as well as intravenous therapy. When conservative management fails, or cause of obstruction could not be managed medically, such as in cases of adhesions or recurrent SOO, or if there is a sense of urgency (e.g., a risk of intestinal necrosis), surgical management is explored. Operative management includes early takedown of the temporary ileostomy, adhesiolysis, or mobilization of the stoma [
2,
7,
10,
13]. The study by Ohira et al. [
12] noted the use of interventional radiology to manage SOO; however, the majority of patients who underwent this ultimately required early closure of the stoma as definitive management. The literature review revealed 2 main treatment options for SOO, but the literature largely focused on preventative measures to reduce the risk of SOO, signifying the need for further research on the management of SOO.
The current study uniquely reports an unusual case of ileostomy volvulus in the absence of adhesions and presents a discussion about the current literature on SBO in ostomy patients. Despite this, some limitations should also be acknowledged. First, due to the paucity of case-control studies, a definitive recommendation through a meta-analysis was not possible. However, the included studies were of good quality, as per the quality assessment tool. Secondly, discrepancies in the definition of SOO may have resulted in underdiagnosis of the pathology and limited the studies available for inclusion in the systematic literature review. Lastly, a larger volume of patients with risk characteristics for SOO (such as loop ileostomies, increased rectus abdominis muscle thickness, or lower preoperative total glucocorticoid dosage) must be included in future studies before these can be stated as definitive risk factors.
In conclusion, this case demonstrates the need for high clinical suspicion of SOO in patients with loop ileostomy, and rapid management should be undertaken. Several factors are associated with SOO, including loop ileostomy, increased rectus abdominis muscle thickness, and lower preoperative total glucocorticoid dosage; however, future studies are needed to evaluate these as risk factors.