Background
Neurogenic bladder dysfunction is a common and serious consequence of traumatic conus medullaris syndrome (T-CMS). Despite its clinical importance, predictive data for bladder outcomes after T-CMS remain limited. This study aimed to identify predictors of neurogenic bladder dysfunction at ≥2 years post-injury.
Methods
We retrospectively reviewed 39 patients with acute T-CMS treated at a single level I trauma center from 2004–2017 who underwent spinal surgery and had ≥2 years of follow-up. Bladder function at 2 years was categorized as complete dysfunction, incomplete dysfunction, or normal. Potential predictors included demographic factors, injury mechanisms, ASIA Impairment Scale grades, MRI timing, fracture level and type, canal diameter, occupying ratio, conus signal change (normal, edema, or edema with hemorrhage), edema length, time to surgery, and surgical approach. Univariate and multivariate analyses were performed.
Results
At final follow-up, 14 patients (35.9%) had complete bladder dysfunction, 12 (30.8%) had incomplete dysfunction, and 13 (33.3%) had normal function. Multivariate analysis identified edema with hemorrhage in the conus medullaris as the only independent predictor of bladder dysfunction.
Conclusions
Bladder dysfunction is highly prevalent after T-CMS. Hemorrhagic edema in the conus medullaris significantly increases the risk of long-term neurogenic bladder dysfunction.

Objective
Postoperative urinary retention (POUR) is a common complication following lumbar spine surgery, significantly affecting functional recovery and Enhanced Recovery After Surgery (ERAS) protocols. POUR can lead to bladder overdistension, infections, prolonged hospital stays, and long-term detrusor dysfunction. Postoperative delirium (POD) can impair cognitive function and mobility, potentially triggering or exacerbating POUR. This study aims to investigate whether POD serves as an independent risk factor for POUR and to analyze other contributing factors to provide clinical management strategies.
Materials and Methods
A retrospective cohort study was conducted involving 420 patients who underwent lumbar spine surgery at a single tertiary medical institution between March 2021 and February 2024. POUR was defined as a post-void residual (PVR) bladder volume ≥300 mL measured via bladder ultrasound or requiring catheter reinsertion due to urinary retention. POD was diagnosed within 72 hours postoperatively using the Confusion Assessment Method (CAM) and was classified into three subtypes: hyperactive, hypoactive, and mixed. Multivariate logistic regression analysis was employed to identify the relationship between POD and POUR, with sensitivity and specificity assessed through Receiver Operating Characteristic (ROC) curve analysis.
Results
Among 420 lumbar spine surgery patients, 44 (10.5%) experienced POD. Of these, 16 (36.4%) were classified as hyperactive, 20 (45.5%) as hypoactive, and 8 (18.2%) as mixed type. POUR occurred in 28 of the POD patients (63.6%) compared to 71 of 376 patients without POD (18.9%), demonstrating a statistically significant difference (p<0.001). The analysis of POUR incidence by POD subtype revealed rates of 62.5% (10/16) for hyperactive POD, 60.0% (12/20) for hypoactive POD, and 75.0% (6/8) for mixed POD. Patients with mixed POD showed the highest POUR incidence, with a significant difference compared to hyperactive and hypoactive POD (p<0.05). Multivariate logistic regression analysis identified POD as an independent risk factor for POUR, increasing the likelihood by approximately 3.7 times (Odds Ratio, OR: 3.71; 95% Confidence Interval, CI: 1.95–7.06; p<0.001). Among POD subtypes, mixed POD presented the strongest association with POUR, increasing the risk by 4.8 times (OR: 4.84; 95% CI: 2.10–11.15; p<0.001). Hyperactive and hypoactive POD were also significant risk factors, increasing POUR risk by 3.0 times (OR: 3.04; 95% CI: 1.45–6.35; p=0.003) and 3.5 times (OR: 3.48; 95% CI: 1.69–7.19; p=0.001), respectively.
Conclusions
This study confirms that postoperative delirium (POD) is an independent risk factor for postoperative urinary retention (POUR) in lumbar spine surgery. The occurrence and subtype of POD significantly influence POUR incidence, with mixed POD presenting the highest risk. These findings highlight the importance of early diagnosis and prevention of POD as a strategy to effectively reduce POUR. A multidisciplinary approach integrating POD and POUR management could optimize postoperative outcomes and improve patient recovery.