Hypothesis / aims of study
Tethered cord syndrome (TCS) is presumed to be a diverse clinical entity characterized by the increased tension of the conus medullaris or cauda equina due to a comparatively low-lying level. Overstrain of the spinal cord could lead to “traction” ischemia and impaired oxidative metabolism, thus manifesting a constellation of tension-induced cord dysfunction symptoms and signs. Surgical untethering is the modality most extensively utilized to treat TCS. It is pretty important to undertake timely surgery for patients with progressive neuro-urological findings and avoid unnecessary surgery for those not at risk of deterioration. Disappointingly, some patients without bladder impairment present a deterioration of bladder function after surgery, which critically influenced the health-related quality of life. Thus, we investigated the effect of untethering on bladder function and provided preliminary surgical indications about bladder function in children with TCS by comparing variations of urodynamic parameters. Moreover, psychological behavior modification in patients was quantitatively evaluated by questionnaires to investigate whether surgery can alleviate the misery endured by patients.
Study design, materials and methods
A total of 55 children diagnosed with TCS from January 2019 to October 2022 were reviewed in the study. Each case underwent meticulous history questioning and whole-body physical examination. Detailed history information should pay attention to surgical history, medications, family history, voiding habits, and whether the patient ever experienced lower urinary tract symptoms (LUTS). Physical examination includes the dorsal spine, cutaneous stigmata, and the lower extremity motor and sensory function. Evaluation for defecation and surgical scars is also imperative. Patients were examined by urodynamics before and after untethering and the examinations are performed by a specially trained practitioner. We compare urodynamic parameters before and after untethering. Maximum cystometric bladder capacity, bladder compliance, detrusor activity, and bladder detrusor sphincter synergy were graded and summed up to obtain the urodynamic score. Additionally, the psychological-behavioral profile of individuals was assessed according to the parent version of the Strengths and Difficulties Questionnaire (SDQ) before pre- and postoperative follow-up.
Subsequently, the children with TCS were divided into two groups according to the preoperative urodynamic parameters and LUTS: the normal bladder function group (Normal group) and the abnormal bladder function group (Abnormal group). The postoperative urinary system of the children in the two groups was analyzed according to the alterations of the postoperative UDS parameters and LUTS. Normal bladder function was defined as urodynamic score ≤4 with no clinical manifestations of LUTS, and improved bladder dysfunction was described as a decreased urodynamic score and reduction in LUTS. According to preoperative symptoms and postoperative clinical outcomes, lower extremity pain and motor dysfunction and intestinal tract dysfunction were classified as improvement (symptoms improved), stability (no change in symptoms but no progression), ineffectiveness (failure to control the disease and continued progression), and aggravation (symptoms worsened) with improvement and stability as effective treatment and ineffectiveness and aggravation as ineffective treatment.
43 children were eligible for inclusion in this study and the Mean ± SD age at surgery was 9.19 ± 2.61 years. The urodynamics before and after untethering showed statistically significant differences in bladder detrusor sphincter synergy (Z = 2.374, P = 0.018) and urodynamic score (Z = 2.500, P = 0.012), and no statistically significant differences in the maximum flow rate (Qmax), post-void residual volume (PVR), maximum cystometric bladder capacity, bladder compliance, and detrusor activity (P >0.05). There was no statistically significant difference before and after untethering in emotional problems, conduct problems, hyperactive attention inability, peer interaction problems, pro-social behavior, and the detection rate of abnormalities in the total score of SDQ difficulties (All P > 0.05 and Table 1). Nevertheless, the detection rate of each psychological behavior abnormality in children with TCS was higher compared with that of normal children, both preoperatively and postoperatively.
24 cases (55.8%) in the Normal group and 19 cases (44.2%) in the Abnormal group; the differences between the two groups in the proportion of male and female gender, lower extremity pain and motor dysfunction, and intestinal tract dysfunction after surgery were not statistically significant (All P > 0.05 and Table 2); the proportion of bladder dysfunction that improved or did not worsen after surgery was higher in the Abnormal group (73.7%, 14/19) than in the Normal group (33.3%, 8/24) (χ2 = 6.910, P = 0.009).
Interpretation of results
No statistically significant differences in most urodynamic parameters indicated that untethering might not considerably ameliorate pre-existing bladder dysfunction. Conversely, the reasons for differences in bladder detrusor sphincter synergy and urodynamic score (postoperative quantitative score higher than preoperative) were as follows: Primarily, despite the application of neurophysiological monitoring techniques, the residual nerves innervating bladder function were inevitably damaged intraoperatively, further aggravating the bladder dysfunction. Moreover, children with LUTS who actively sought medical attention were included in the study, while bias such as non-attendance of children with improved bladder dysfunction due to adherence problems could also affect the results.
Children with TCS, caregivers, and medical practitioners commonly had a multitude of concerns regarding neurogenic bladder, medications, and economic spending. No statistically significant differences in psychological behavior and the higher detection rate of each psychological behavior abnormality underlined that TCS plague patients all the time even if untethering. The presence of lower limb deformities and the inability to control urination and defecation in patients contribute to a series of mental disorders such as low self-esteem and depressed feelings. This phenomenon may be related to the lack of complete remission of symptoms, short follow-up time, and insufficient attention to the family environment and psychological care counseling and education.
Bladder function worsened in 66.7% of children in the Normal group, whereas bladder dysfunction improved or stabilized in 73.7% of children in the Abnormal group following surgery. This revealed that untethering was generally not recommended for children without preoperative bladder dysfunction, whereas the presence of preoperative bladder dysfunction might be additional evidence for aggressive surgical intervention. Notably, some children with preoperative bladder dysfunction couldn’t benefit from surgery, or even worsen, which was demonstrated as a nexus with neurological damage risk.