When and how are complications suspected after shunt surgery in patients with normal pressure hydrocephalus?

Acta Neurochirurgica (2025) 167:6

The follow-up routine for patients with idiopathic normal pressure hydrocephalus (iNPH) after shunt surgery differs across medical centers. Shunt surgery is not without risks, with complications emerging at various times after the procedure. The aim was to explore the timing and methods of detecting complications following ventriculoperitoneal shunt surgery for iNPH.

Methods This retrospective study examined patients who underwent shunt surgery for iNPH at Uppsala University Hospital between 2011 and 2018. The cohort comprised 491 patients. Postoperative complications within the first 12 months were recorded from medical records. Complications were classified by type, and the method or event that first indicated the complication was documented.

Results Of the 491 patients, 102 (20.8%) experienced complications during the one-year follow-up period, with a shunt revision rate of 15.5% (76 patients requiring reoperation). Subdural hematomas/hygromas were the most common complications, with 27 cases; only three required surgical intervention. Most complications were identified through additional appointments triggered by patient-reported symptoms (31.4%), while the planned follow-up routine with CT scans and planned follow-up visits together accounted for 56% of the detections. The 3-month and 12-month follow-up visits detected similar proportions of complications (12.7% and 11.8%, respectively).

Conclusion The majority of the complications were detected at a planned visit or investigation. Given the cognitive impairments in iNPH patients and that signs of shunt dysfunction can be subtle, a structured follow-up routine is important for timely detection of complications. The findings suggest that both CT scans and planned follow-up visits are critical components of effective postoperative monitoring.

Outcomes and complications of different surgical treatments for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis

J Neurosurg 131:1024–1036, 2019

Different CSF diversion procedures (ventriculoperitoneal, ventriculoatrial, and lumboperitoneal shunting) have been utilized for the treatment of idiopathic normal pressure hydrocephalus. More recently, endoscopic third ventriculostomy has been suggested as a reasonable alternative in some studies. The purpose of this study was to perform a systematic review and meta-analysis to assess overall rates of favorable outcomes and adverse events for each of these treatments. An additional objective was to determine the outcomes and complication rates in relation to the type of valve utilized (fixed vs programmable).

METHODS Multiple databases (PubMed, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus) were searched for studies involving patients with idiopathic ventriculomegaly, no secondary cause of hydrocephalus, opening pressure < 25 mm Hg on high-volume tap or drainage trial, and age > 60 years. Outcomes included the proportion of patients who showed improvement in gait, cognition, and bladder function. Adverse events considered in the analysis included postoperative ischemic/hemorrhagic complications, subdural fluid collections, seizures, need for revision surgery, and infection.

RESULTS A total of 33 studies, encompassing 2461 patients, were identified. More than 75% of patients experienced improvement after shunting, without significant differences among the different techniques utilized. Overall, gait improvement was observed in 75% of patients, cognitive function improvement in more than 60%, and improvement of incontinence in 55%. Adjustable valves were associated with a reduction in revisions (12% vs 32%) and subdural collections (9% vs 22%) as compared to fixed valves.

CONCLUSIONS Outcomes did not differ significantly among different CSF diversion techniques, and overall improvement was reported in more than 75% of patients. The use of programmable valves decreased the incidence of revision surgery and of subdural collections after surgery, potentially justifying the higher initial cost associated with these valves.