Objective To investigate the characteristics and clinical significance of anorectal manometry measurements in children with tethered cord syndrome (TCS) before and after surgery. Methods A retrospective study was conducted on 44 children with TCS treated at the Children's Hospital of Zhejiang University School of Medicine from January 2022 to September 2023. These patients were divided into effective subgroup (n=34) and non-effective subgroup (n=10) based on postoperative symptom improvement. Additionally, 34 children with functional constipation were selected as a control group. Baseline data and manometry measurements were compared between the preoperative TCS group and the control group, as well as between the non-effective and effective subgroups. Results The TCS group had lower short contraction time and defecation relaxation rate compared to the control group (P<0.05), while defecation residual pressure and maximum rectal tolerable threshold were higher than the control group (P<0.05). The length of the anal canal in the high-pressure zone in the effective subgroup was greater postoperatively than preoperatively (P<0.05), and the initial rectal sensation threshold decreased postoperatively (P<0.05). The non-effective subgroup had lower preoperative maximum rectal expulsion pressure compared to the effective subgroup (P<0.05). Postoperative rectal anal inhibition reflex values in the effective subgroup were higher than those in the non-effective subgroup (P<0.05). Conclusions There are some differences in anorectal dynamics between children with TCS and those with functional constipation. Maximum rectal expulsion pressure may be a key predictor of surgical outcomes. Surgery can alter certain defecation functions in some children.