Objective Tarlov cysts, commonly referred to as Sacral perineural cysts, were first identified by Tarlov in 1938 as incidental findings during autopsy. However, their clinical significance remains controversial due to the limited and heterogeneous data available in the literature. Most published studies are based on small cohorts, resulting in inconsistent conclusions and the absence of standardized treatment recommendations. The present study aims to further elucidate the clinical relevance of Tarlov cysts and to explore the underlying mechanism of intracystic hydrostatic pressure and evaluate the clinical efficacy and safety of microsurgical perineurium reconstruction in the treatment of sacral nerve root (radicular) cysts. Methods A retrospective review was conducted on 26 patients diagnosed with sacral radicular cysts who underwent surgical treatment at the Second Hospital of Shanxi Medical University between November 2016 and June 2019. All patients received subtotal cyst resection combined with microsurgical perineurium reconstruction. Clinical data including presenting symptoms, intraoperative findings, and postoperative outcomes were collected. A subset of 10 patients underwent intraoperative measurement of intracystic hydrostatic pressure under different body positions to investigate pressure dynamics. Postoperative follow-up was carried out through outpatient visits and telephone interviews, ranging from 5 to 49 months, with a mean duration of (28.04 ± 12.57) months. Results The most common clinical manifestations were lumbosacral pain and radiating pain in the lower limbs. All 26 patients successfully underwent the microsurgical procedure without the occurrence of new neurological deficits, wound infection, or other surgical complications. Postoperative symptoms improved in 25 patients (96.2%), while one patient (3.8%) showed no improvement. No wound infections or new complications were observed. Patients were followed for 5-49 months (mean: 28.04 ± 12.57 months). There were statistically significant decreases (p < 0.05) in the M-JOA low back pain scores from preoperative (26.32 ± 1.75) to postoperative (14.92 ± 5.95) values, as well as a significant improvement (p < 0.05) in the NRS pain scores from preoperative (2.02 ± 1.46) to postoperative (6.23 ± 1.20). Preoperative intracapsular pressure ranged from 3.1 to 12.4 mmHg across different positions. Postoperative sacral canal pressure ranged from 0.1 to 0.8 mmHg in various positions. These findings suggest a correlation between elevated intracystic pressure and the severity of clinical symptoms, as well as a potential mechanism by which cysts exert compressive effects on nerve roots. Conclusions Sacral radicular cysts predominantly present with lumbosacral and lower extremity pain and may be associated with elevated intracystic hydrostatic pressure. Microsurgical subtotal cyst excision combined with perineurium reconstruction is an effective and safe surgical option that results in significant symptom relief and low complication rates. Intraoperative intracystic hydrostatic pressure measurements may provide insights into symptomatology and serve as a supplementary diagnostic and evaluative tool during surgical planning. These results support the use of targeted microsurgical intervention in selected patients with symptomatic sacral radicular cysts.