Patients with spinal cord injury (SCI) often develop neurogenic lower urinary tract dysfunction (NLUTD), with detrusor sphincter dyssynergia (DSD) being a prevalent and clinically significant condition. The severity of DSD is classified into three grades, with higher grades may associated with increased risk of urological complications. However, few studies have systematically compared these complications across different DSD grades.

We conducted a retrospective study of 543 SCI patients diagnosed with neurogenic detrusor overactivity (NDO) and DSD using video urodynamicstudy (VUDS) and electromyography (EMG) evaluations. Patients were categorized into non-DSD, DSD grade 1, DSD grade 2, and DSD grade 3 groups. (Figure 1) The primary outcome was the incidence of urological complications including recurrent urinary tract infection (rUTI), renal stone, bladder stone, vesicoureteral reflux (VUR), hydronephrosis, autonomic dysreflexia (AD) among different groups. The secondary outcome uses logistic regression models to assess the association between different DSD grades, bladder management strategies, VUDS parameters and the occurrence of complications.

Higher DSD grades were significantly associated with an increased risk of rUTI and AD. (Table 1) Spontaneous voiding was linked to a lower risk of both complications, whereas CIC was associated with a higher incidence of rUTI, and IDC was linked to an increased risk of AD. However, VUDS parameters were not significantly correlated with the occurrence of complications. Subgroup analyses further revealed that CIC was associated with a higher risk of hydronephrosis in patients with DSD grade 1, while IDC was linked to an increased risk of AD in patients with DSD grade 3. (Table 2)

This study investigated the relationship between DSD severity, bladder management strategies, and the incidence of urological complications in SCI patients. Our findings indicate that higher DSD severity is associated with an increased risk of rUTI, while AD occurs more frequently in DSD grade 3 patients. Additionally, bladder management methods appear to influence these risks, with CIC associated with rUTI and IDC linked to AD. These results provide further insights into the factors contributing to urological complications in SCI patients with DSD. In the following sections, we compare our findings with previous studies and explore potential mechanisms underlying these associations. We observed that more severe DSD was associated with a higher risk of rUTI. The underlying mechanisms may include the fact that patients with more severe DSD are often more reliant on catheterization for bladder emptying rather than spontaneous voiding, which inherently increases the risk of infection. Additionally, prolonged use of catheters in these patients may damage the bladder’s epithelial barrier, facilitating bacterial colonization and potentially leading to biofilm formation and chronic infection. Moreover, in SCI patients with DSD, the loss or reduction of bladder sensation is common, which may result in an incorrect bladder management strategy. This, in turn, can lead to bladder overdistension, further increasing the risk of rUTI. Additionally, in our study findings, we observed a significantly higher risk of AD in patients with DSD grade 3. These findings align with previous studies that have identified severe DSD as a major risk factor for AD. Reinforce the notion that voiding dysfunction severity plays a crucial role in AD susceptibility.

This study reveals the complex relationship between DSD severity, bladder management strategies, and urological complications in SCI patients. Higher DSD grades are linked to poorer VUDS parameters and increased risks of rUTI and AD. Instead, bladder management strategies play a crucial role. Clinically, individualized bladder management is essential, especially for severe DSD cases. Catheterization should be tailored to the patient’s SCI severity, catheterization ability, and urinary tract condition. Regular follow-up is vital to adjust management based on complications, VUDS changes, and quality of life, ensuring optimal care.

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