Background Urinary and sexual dysfunction are underrepresented complications in spine surgery literature, despite their significant impact on postoperative quality of life among male patients. These outcomes are particularly relevant in lumbar procedures, where autonomic and somatic structures critical to erectile, ejaculatory, and excretory functions are at risk. Anterior instrumentation may disrupt the hypogastric plexus and sympathetic chains, while posterior operations pose injury to nerve roots. However, comparative data on genitourinary complications by surgical approach in men remains limited.

Methods The TriNetX Research Network was queried to identify adult males who underwent two- to seven-level vertebral instrumentation between 2010 and 2023 for lumbar, lumbosacral, or thoracolumbar stenosis, spondylolisthesis, scoliosis, or radiculopathy. Patients were categorized by anterior or posterior surgical approach. Those with complex spinal pathology, preexisting urogenital disorders, or a history of the opposite approach were excluded. Propensity score matching adjusted for age, ethnicity, and relevant comorbidities. Postoperative outcomes were identified using diagnostic and procedural codes.

The primary outcome was a composite measure of urinary complications (pain, incontinence, retention, extravasation, anuria, oliguria, polyuria, urethral discharge, and other specified and unspecified urinary dysfunction). The secondary outcome was a composite measure of sexual complications (pain, erectile/ejaculatory dysfunction, decreased libido, and other specified and unspecified sexual dysfunction). All outcomes were assessed at one, three, six, nine, and twelve months postoperatively.

Results A total of 11,164 patients met all initial inclusion criteria (7,763 posterior, 3,401 anterior); following 1:1 propensity score matching, each cohort included 3,397 patients with comparable baseline characteristics. Post-matching analysis revealed that posterior instrumentation was associated with significantly higher odds of urinary complications at one month (OR=2.259), three months (OR=1.727), six months (OR=1.374), nine months (OR=1.339), and twelve months (OR=1.333). No significant difference in sexual complications was observed at earlier intervals, however, anterior instrumentation patients exhibited higher odds at twelve months (OR=0.630) postoperatively.

Conclusion In this large, multicenter retrospective analysis of adult males undergoing multilevel spinal instrumentation, surgical approach was associated with distinct patterns of genitourinary complications. Posterior instrumentation carried consistently higher odds of urinary dysfunction, suggesting increased vulnerability of nerve roots involved in micturition. Sexual outcomes were comparable between groups until twelve months, when anterior instrumentation was linked to increased complications, potentially reflecting delayed effects on regional autonomic pathways. These findings underscore the importance of surgical approach in influencing long-term functional outcomes and may inform preoperative counseling and risk stratification in male spine surgery patients.