Colocolic intussusceptions in children are far less common than ileocolic intussusceptions, occurring in less than 5% of most case series except on the African continent, and most have a pre-existing colonic pathology acting as a lead point [5, 6, 25, 26]. The incidence of colocolic intussusception was 0.8% at our center, a value lower than that reported in the literature. The reason might be related to ethnic and geographic differences. Additionally, patients with intussusception treated successfully by air enema at the outpatient department were not included in our case series, which affected the incidence. A review of the studies published in the past 20 years showed that unlike the male predominance reported in previous studies on all types of intussusception, no such predominance was identified among patients with colocolic intussusception, as reported in previous surveys [26]. Our study also confirmed that the age at the development of colocolic intussusception was older on average than that of patients with ileocolic intussusception [27, 28]. The reason might be associated with pathologic lead points, such as juvenile polyps, which occur most commonly in children older than 2 years of age [29].
The clinical symptoms of abdominal pain, bloody stool and vomiting are often considered the main features of intussusception. However, less than 25% of patients have this classic triad, leading to a delayed diagnosis or misdiagnosis [30]. Among patients with colocolic intussusception in our study, the proportion with the above classic triad was as high as 43.2%, but 37.8% were still misdiagnosed. The reason was mainly related to the less severe symptoms of the patients at the initial visit, lack of imaging examination or successive occurrence of the above symptoms [5, 6]. Our study also confirmed that, unlike patients with ileocolic intussusception who almost always had abdominal masses, a significantly lower proportion of patients with colonic intussusception had abdominal masses, most of which were located in the left abdomen; instead, patients with colonic intussusception had a significantly higher incidence of rectal masses or prolapse. Both ultrasound and computed tomography are useful tools to diagnose intussusception [31]. Ultrasound is recommended first and should be used at the initial visit for all children with the above symptoms and a clinical suspicion of intussusception, including colocolic intussusception [32].
Given the pathologic lead points found in most colocolic intussusceptions, therapeutic enemas, especially hydrostatic barium enemas, were previously considered to be avoided, and these patients often required open surgery [33]. However, treating colocolic intussusception caused by a pathologic lead point is currently considered the same as treating those without a pathologic lead point, involving a careful attempt at reduction using a minimally invasive approach [7]. Similar to the findings in the recent systematic review of intussusception, our study suggested that for colocolic intussusception, without peritonitis (e.g., diffuse abdominal tenderness), a therapeutic enema could be performed first [34]. The success rates of a therapeutic enema to the treat colon intussusception with and without pathologic lead points in our study were 52.9% (9/17) and 75.0% (3/4), respectively. A colonoscopy can be performed to investigate the colon wall and identify the pathologic lead point in patients with successful therapeutic enemas and performing a colonoscopy can sometimes help reduce intussusception in patients in whom the therapeutic enema has been unsuccessful [6, 7].
As described in most studies in the literature, active intervention is required for colocolic intussusception caused by pathologic lead points because the presence of lead points may impair complete reduction of intussusception and the recurrence rate is still high even after a successful therapeutic enema [6, 10, 33]. According to our study, juvenile polyps are the most common lead point in patients with colocolic intussusception, and using a therapeutic enema followed by colonoscopic polypectomy was found to be a feasible intervention to treat these patients. Among the 7 patients with successful therapeutic enemas who underwent colonoscopy subsequently, 6 (6/7, 85.7%) had their polyps successfully removed, and 1 with a sessile polyp found during colonoscopy underwent segmental colonic resection. Additionally, to our best knowledge, the current study reported the largest variety of pathologic lead points of colocolic intussusception other than juvenile polyps and found that all patients with colocolic intussusception caused by other pathologic lead points had received surgical interventions (12 open surgeries, 2 laparoscopic surgeries and 2 colonoscopic polypectomies), except for 1 with colocolic intussusception caused by hereditary angioneurotic edema. The main reasons for the increased use of open surgery may be as follows. First, most pathologic lead points were rare, and clinicians lacked the awareness and treatment experience of these intussusception types. Second, even if the intussusception was successfully reduced by therapeutic enema, some pathologic lead points, such as synovial sarcoma and lipoblastoma, could not be removed by colonoscopy. Third, after successful reduction by therapeutic enema, some pathologic lead points located outside the colon could not be observed by colonoscopy, such as the ileal invagination of the sigmoid colon [12, 23, 24]. Additionally, Abrahams et al. reported 1 patient with colocolic intussusception caused by a juvenile polyp who had undergone laparoscopic exploration after a successful therapeutic enema, but no abnormality was found; the patient had undergone open surgery subsequently because of the recurrence of symptoms [10]. Thus, open surgery remains the primary treatment in patients with colocolic intussusception and may be preferable to laparoscopic surgery. However, the identification rate of pathological lead points by open surgery also did not reach 100.0%. For example, the case of colocolic intussusception caused by capillary hemangioma reported by Utsumi et al. could only be accurately resolved by open surgery with colonoscopic assistance [17]. Further studies with larger samples are needed to confirm this finding.
With advances in ultrasound and computed tomography, an increasing number of patients can be diagnosed with or without pathologic lead points [17, 33]. If the colocolic intussusception caused by pathologic lead points was reduced by therapeutic enema, we recommended that patients be hospitalized for a period of time to relieve bowel edema and receiving adequate bowel preparation before deciding the best way to manage the pathologic lead points, an approach that could be helpful for reasonable surgical selection and improve the overall prognosis [7]. However, except for juvenile polyps, identifying the specific type of lead points preoperatively remains challenging. No study has reported the differences in imaging findings between different pathologic lead points, which would be helpful to develop a standard diagnosis and treatment procedure for colocolic intussusception in the future.
The study has several limitations. First, all the included studies were retrospective, and the patient population was small. Second, some studies had not fully reported the results, which may have confounded the findings. Finally, literature reviews did not include all published studies (before 2000), leading to potential bias. A multicenter prospective study of colocolic intussusception is recommended in the future.