Hydrostatic saline enema with USG guidance proves to be an effective reduction method, achieving the desired outcome even in cases with unfavorable clinical manifestations. Nevertheless, the likelihood of success shows a slight decline when dealing with an increased number of symptoms, signs, or findings and greater intussusception extent into the caecum. Except for the location of intussusception, none of the measured variables have a significant impact on the likelihood of recurrence within 3 days following a successful procedure. Overall, recurrences were an uncommon finding.

The oldest non-operative method for reducing intussusception, once considered the “golden standard”, is a hydrostatic reduction with barium under fluoroscopic monitoring. Guo et al. [10] investigated the success rate of this method in a study conducted in the People’s Republic of China in 1986, which included 6296 cases collected over a 13-year period. Their findings estimated a 95% likelihood of achieving the desired outcome with this approach. In modern practice, it is being replaced by pneumatic or hydrostatic saline enema due to concerns about limiting radiation exposure, potential complications like chemical peritonitis, risk of infection, and adhesions when perforation occurs [7, 11].

The effectiveness of the method described in this study—reducing intussusception using warm saline enema guided by real-time sonography—was initially documented by Kim et al. [12] in 1982, with successful outcomes observed in two patients.

The results of the present study reflect an overall success rate of 86.7% for this method. Studies of a similar sample size such as those conducted by Flaum et al. [13] report a success rate of 83% and by Miguel et al. [14] of 85.8%. In our series, the overall success rate aligns closely with published findings, irrespective of the study group count, ranging from 76.8% [8] to 95.5% [15].

Our study highlights the significant influence of intussusception’s location on the success of non-operative treatment. We observed a relatively lower success rate for intussusceptions located in the transverse colon and rectum, contrasted by a notably high success rate for those situated in close proximity to the ileocecal valve. Flaum et al. [13] found the highest success rate for the location of ascending colon (94%), transverse colon (88%), and ileocecal region (84%), while the lowest success rates were noted for occurrences in the left colon (35%). Our findings diverged from theirs concerning success rates in the transverse colon region. Fike et al. [8] in the study solely concerning predictors of failed enema reduction also noticed a correlation between the location of intussusception and a failure of hydrostatic saline enema reduction, with the lowest failure rate for the right colon and the highest in the rectosigmoid and descending colon. Our data also supports the rather intuitive notion that the more distal intussusception is less likely to be reduced with enema; however, we had insufficient data to analyze incidents occurring in the descending colon.

This study concerns clinical manifestations observed in patients with intussusception. Our study group was quite heterogeneous regarding signs and symptoms. Emesis was found to be the most prevalent symptom, present in 42% of patients. Studies by Talabi et al. [6] and Kaiser et al. [16] also revealed vomiting to be the most common symptom, with the presence of nearly 100%.

Predicting which patients are prone to unsuccessful enema reduction holds clinical significance as it can assist healthcare providers in pinpointing those less likely to derive benefit from a subsequent enema reduction attempt. This study’s findings have shown that the presence of free fluid in the peritoneal cavity, emesis, and diarrhea can be associated with failure. Potential correlation between the need for surgical treatment and clinical manifestations has been previously studied. In the study published by Flaum et al. [13], clinical symptoms were not associated with the reduction success; however, Fike et al. [8] and Peyvasteh et al. [17] recognized currant jelly stool and the presence of free peritoneal fluid as failure factors in the non-surgical treatment.

Several studies [1, 8, 17] have observed a decrease in the effectiveness of non-invasive procedures when the duration of symptoms exceeds 24 h. We did not obtain analogous results, as in our case results were statistically insignificant. This might indicate that children with prolonged symptoms should not be denied non-operative treatment solely based on this factor.

Our study investigated the likelihood of intussusception recurrence. We had a total of 37 episodes of recurrences in 27 (17.1%) patients. This recurrence rate is higher when compared to studies published by Delgado-Miguel et al. [14], Flaum et al. [13], and Sun et al. [18], in which recurrence rates ranged from 7.5 to 8%. These studies investigated cases of both late and early recurrences with intervals ranging from 1 day to 21 months post-attempted reduction. Our analysis looked into early recurrences with varying time spans from 1 to 3 days. A study by Karakus et al. [19], which inquired into early recurrences, up to 48 h, obtained a rate of 15.7%, which is similar to ours. Hence, we believe that early recurrences identified following hydrostatic reduction of intussusception under US guidance may likely represent insufficient or “false-positive” reductions. It is worth noting that US-guided intussusception reduction has demonstrated a 16% rate of false positives and a 14% rate of false negatives [20].

Our research examined potential predictive factors for the recurrence of pediatric intussusception. We found that as the number of symptoms increased, there was, on average, a 50% likelihood of recurrence. Recurrence was more common in our patients who had the primary location of intussusception in the rectum. Our analysis did not discern a statistically significant correlation between the occurrence of a specific sign, symptom, or ultrasonography (USG) finding and the likelihood of recurrence. In the study conducted by Xie et al. [21] to evaluate risk factors for the recurrence of intussusception in pediatric patients, duration of symptoms > 48 h, rectal bleeding, and location of mass on the left side were identified as significant. Although in our study duration of symptoms ranging from 1 to 48 h did not increase the risk of recurrence, the data required for analysis of a period longer than 48 h was insufficient.

The incidence of pathological lead point (PLP) in all children in our study group was 6.01%. The most common PLP was Meckel’s diverticulum. All of the patients with PLP had unsuccessful reduction with enema. In 2016, Ntoulia et al. [4] investigated predictors of failed contrast enema, revealing that PLP was a reason behind failure in 25% of patients. They also noted that although screening ultrasound can decrease the number of unnecessary enema reduction attempts, diagnosing classic pathologic lead points such as Burkitt lymphoma and Meckel diverticulum may be difficult with the use of ultrasound [4]. In our study, four patients underwent surgery as a primary treatment due to the presence of PLP, which was revealed using different screening methods than ultrasound-computed tomography.

Ultrasound-guided hydrostatic saline enema reduction method offers several advantages over alternative methods, such as intracolonic pressure remaining stable throughout the procedure, when compared to the pneumatic enema. In contrast to pneumatic reduction, there is no risk of tension pneumoperitoneum—a life-threatening complication, where abdominal pressure instantly increases, potentially causing for example compression of the inferior vena cava [22]. Even in the rare event of perforation, there is a minimal likelihood of chemical peritonitis, a risk often associated with the use of barium. Importantly, this method eliminates the hazard of radiation exposure, prioritizing patient safety. Additionally, the ultrasound modality allows for the detection of potential lead points for intussusception, such as Meckel’s diverticulum or duplications, aiding in a more comprehensive evaluation and treatment [11].

One significant drawback associated with this method is the requirement for an accessible sonologist who is proficient in utilizing this method for enema guidance [15].

The study has several limitations that need to be considered. Firstly, it is a unicentric study, potentially limiting the generalizability of the findings to a broader population. Additionally, the study’s retrospective design introduces inherent limitations, as it relies on historical data and may not capture all relevant variables or control for potential confounding factors. Therefore, while this study provides valuable insights, these limitations stemming from its unicentric nature and retrospective design should be taken into account when interpreting the results.