Negative CSF mNGS Results and Early Shunt Placement in Post-infectious Hydrocephalus: A Retrospective Cohort Study

To evaluate the impact of pre-shunt cerebrospinal fluid (CSF) metagenomic next-generation sequencing (mNGS) guidance on the timing of ventriculoperitoneal (VP) shunt surgery and clinical outcomes in patients with post-infectious hydrocephalus (PIH), and to explore the value of mNGS in different clinical scenarios.

In this retrospective cohort study, we included 42 patients with PIH who underwent VP shunt surgery at our institution between January 2019 and December 2025. Patients were divided into 2 groups according to whether pre-shunt CSF mNGS was performed: the mNGS group (n=19) and the non-mNGS group (n=23). Primary outcomes included recovery to shunt time (RTS), first negative to shunt time (NTS), decisional shunt to actual shunt time (DTS), and postoperative antibiotic time (PAT). Secondary outcomes included postoperative hospital stay (POHS), functional outcomes (mRS and GCS), POD 90 mortality, infection recurrence, and reoperation.

Compared with the non-mNGS group, the mNGS group demonstrated significantly shorter NTS (3 [IQR: 1-4] days vs. 9 [IQR: 4.5-17] days, P=0.002), DTS (2 [IQR: 1-3.5] days vs. 8 [IQR: 6-18] days, P<0.001), and PAT (0 [IQR: 0-2] days vs. 4 [IQR: 0-10] days, P=0.010). No significant differences were observed between the 2 groups in RTS (P=0.135), functional outcomes, mortality, infection recurrence, or reoperation.

Pre-shunt CSF mNGS testing significantly shortens NTS, DTS, and PAT in patients with PIH without compromising clinical outcomes. The mNGS-guided shunt strategy is safe and feasible, supporting its potential clinical application.