Minimally invasive suboccipital tubular resection of large posterior fossa metastases: Early ventricular decompression and low CSF diversion rates.

OBJECTIVE

Posterior fossa metastases carry a high risk of brainstem compression and obstructive hydrocephalus, with no consensus on optimal perioperative cerebrospinal fluid (CSF) diversion. We evaluated early fourth ventricular decompression, CSF diversion, and perioperative outcomes following minimally invasive tubular resection in patients with relatively large tumors.

METHODS

We performed a retrospective single-center study of 29 consecutive adults undergoing minimally invasive suboccipital tubular resection of previously untreated posterior fossa metastases. Primary outcomes were postoperative CSF diversion and early ventricular decompression. In the absence of a comparator cohort, outcomes were interpreted relative to published series.

RESULTS

The median tumor volume was 11.4 cm³ (IQR, 10.1-17.8 cm³). Preoperative hydrocephalus was present in 48% of patients, and 55% had high-grade fourth ventricular compression. Within 24 h postoperatively, high-grade compression decreased to 21%, with 79% demonstrating mild or no residual compression. Among patients with preoperative hydrocephalus, 64% showed early improvement. Postoperative CSF diversion was uncommon: no patients required external ventricular drainage, and one patient (3%) required ventriculoperitoneal shunting. Gross-total resection was achieved in 72% of evaluable cases, with operative strategy prioritizing safe decompression. Ninety percent of patients were stable or improved at discharge, with a median length of stay of 3 days. There were no CSF leaks, infections, or postoperative hemorrhages. Thirty-day mortality was 7%.

CONCLUSION

Minimally invasive tubular resection enables effective decompression of relatively large posterior fossa metastases with low CSF diversion rates. These findings are hypothesis-generating, and comparative studies are required to define the role of this approach relative to conventional techniques.