This study aimed to compare the surgical outcomes in patients with VEO-UC with those of older pediatric UC patients. Our study found that 1) VEO-UC patients did not have significant difference of surgical complication rates compared to older pediatric UC patients, except for high-output ileostomy; 2) VEO-UC patients had a higher ileostomy output, resulting in a prolonged duration of ileostomy and CVC placement; and 3) postoperative growth recovery of patients with VEO-UC might be comparable to that of pediatric patients with UC.
The colectomy rate for pediatric UC is reportedly higher than that for adult UC. Siow et al. reported that the 10-year colectomy rates in pediatric patients range from 30% to 40% compared with 15–25% in adults [14]. The present study showed that the colectomy rate of the VEO-UC group was significantly higher than that of the older pediatric patients with UC. However, half of our patients with VEO-UC were referred from other distant prefectures for undergoing surgery. This patient selection bias might have influenced the higher colectomy rate of the VEO-UC group in our cohort. Benchimol et al. reported that the colectomy rate in VEO-UC patients was lower than that in pediatric UC patients over 10 years of observation (8.2% vs. 17.7%) [6]. A study focusing on IBD by Cucinotta et al. reported that the surgical risk of patients with VEO-IBD was significantly higher than that of older pediatric patients with IBD (32% vs. 14%) after 10 years of observation [15]. Comparison between the colectomy rate of the VEO-UC and older pediatric UC remains controversial.
A previous study has shown that younger patients with VEO-IBD have a shorter duration from diagnosis to colectomy: Among patients who develop VEO-IBD during the first year of life, approximately one-third require surgical treatment within the first year after onset [16]. In the present study, the duration from diagnosis to colectomy was not different from that in older pediatric UC patients, although the VEO-UC patients who underwent surgery at our institution were diagnosed with UC at < 2 years of age. Duration from diagnosis to colectomy may have been affected by progress in medical therapies and disease severity of the included patients.
The surgical complications of UC include pelvic sepsis, anastomotic leakage, anastomotic stricture, and pouchitis, while complications of ileostomies include outlet obstruction, prolapse, and high-output ileostomies. General surgical complications include wound infection and small-bowel obstruction [17]. Pediatric patients with UC appear to have a different clinical course than adults. Tan Tanny et al. found a higher incidence of pouchitis and lower rates of pelvic infection in this population [18]. Similarly, Rinawi et al. suggested that pouchitis is more common in younger patients with pediatric UC [19]. In terms of surgical complications in pediatric population, Knod et al. reported rates of 17–50% for bowel obstruction, 5–13% for anastomotic leak, 9–27% for stricture, and 24–29% for pouchitis [20]. The present study revealed that the rate of surgical complications in patients with VEO-UC did not differ from that in older pediatric UC patients, except for high-output ileostomy. The complication rate of VEO-UC in our study was comparable to that of pediatric UC in previous studies [18,20].
High-output ileostomy occurs when fluid loss through ileostomy exceeds the patient’s compensatory mechanisms, resulting in dehydration, acute kidney failure, and even death. The causes of this condition are not yet fully understood [21]. Knod et al. reported that the rates of dehydration after colectomy among pediatric UC patients aged over and under 11 years were 5.3% and 15.4%, respectively [20]. This data indicates that dehydration is more common in younger patients, which supports our findings. It was very interesting that there was a difference in the amount of ileostomy by age, however, details could not be assessed because the management for high-output ileostomy was not protocolized.
The treatment of high-output ileostomy involves replenishing lost electrolytes and fluids, along with measures to decrease defecation. Therefore, prolonged high-output ileostomy results in a longer duration of placement of a CVC. Actually, significantly longer duration of CVC replacement was observed in VEO-UC in the present study. The long duration of CVC replacement often results in the more frequent occurrence of CRBSI. In the present study, although there was no significant difference in number of CRBSIs/1,000 catheter days, patients with VEO-UC had 2 CRBSIs/1,000 catheter days while the older pediatric UC patients had no CRBSI. Shibata et al. reported that the incidence of CRBSI in IBD and non-IBD adults was 13.2 and 0.40 infections per 1000 catheter days, respectively [22]. Therefore, long duration of CVC replacement against UC patients is apparently a risk CRBSI. Early detection and appropriate treatment of CRBSI is essential.
In our study, we found that patients with VEO-UC had a significantly lower Z-score for height at the time of colectomy compared with older patients with UC. This suggests that the growth of VEO-UC patients may be more adversely affected by the disease compared with the growth of older patients, as there was no significant difference in the time from UC diagnosis to colectomy between the two groups. Furthermore, although the Z-score of height 2 years after colectomy was also significantly lower in patients with VEO-UC, the change in the height Z-scores before and after colectomy was comparable to that in older pediatric patients with UC. The effect on postoperative growth after surgery for patients with VEO-UC and for older pediatric patients with UC was not significantly different. Nicholls et al. reported that the growth velocity of height is accelerated nearly two-fold after surgery in pediatric patients [23]. Moreover, Sako et al. reported that a growth “catch-up” has been obtained in 14 out of 15 pediatric UC patients [24]. There are no detailed data on pre- and postoperative Z-scores of anthropometric measurements in pediatric UC patients; therefore, to our knowledge, this is the first study to show the effect of surgery on postoperative growth using Z-scores in pediatric UC patients.
This study has some limitations. Firstly, VEO-IBD is a complex and heterogeneous disease, and the diagnosis of VEO-UC may change as the patient ages [25]. Rialon et al. reported that 24% of patients originally diagnosed with UC or IBD-unclassified were later reclassified as having Crohn’s disease [26]. In this study, the diagnosis of VEO-UC was based on endoscopic findings, and genetic testing was not performed in all cases, meaning that underlying immunodeficiency and monogenic etiologies were not thoroughly ruled out. However, small intestinal lesions were not detected in any of the VEO-UC cases, and the diagnosis of VEO-UC did not change during a median postoperative follow-up period of 6.4 years. Lastly, we did not compare the postoperative quality of life, which is one of the most important surgical outcomes. Future studies are needed to address this aspect.