A total of 78 records were identified through database searches. After removing 24 duplicate entries and 6 records not published in English, 48 unique records remained for screening. During the title and abstract screening phase, 7 records were excluded due to irrelevance. Of the 41 papers sought for retrieval and full-text assessment, 19 were excluded because they did not report clinical case series or case reports. Additionally, 4 reports were excluded due to overlapping patient populations already discussed in other included studies, albeit under a different aspect. Furthermore, 27 articles were further excluded for different reasons as explicitedly detailed in Fig. 1. Finally, 18 studies were included in the final review (Fig. 1; Table 1,2), whose quality was assessed using ROBINS-I V2 tool for risk of bias evaluation (Fig. 2).
The study selection process was documented using the PRISMA 2020 flowchart, outlining the stages of identification, screening, eligibility assessment, and final inclusion (Fig. 1).
Qualitative analysis (Systematic Review)
A total of 148 patients were reported across all studies (Tables 1–2). Of these, 32 (21.6%) presented with subdural hematoma (SDH), 39 (26.4%) with isolated intraventricular hemorrhage (IVH), and 7 (4.7%) with ventriculitis [1, 2, 12, 13, 17–22]. An additional 70 patients (47.3%) were treated for either SDH or IVH, but further stratification was not possible [18].
Among SDH patients with available data (n = 32), the catheter tip was placed in the subdural space in all cases. Most underwent freehand implantation via single burr hole (29/32; 90.6%), while 2 (6.3%) received neuronavigation-assisted placement through minicraniotomy, and 1 case lacked procedural details [9, 11, 12, 14, 18, 21, 23–27]. The mean treatment duration ranged from 1 to 5 days. Irrigation rates varied between 10 and 100 mL/h [9, 13, 19, 21, 23, 25–27]. Only one case (3.1%) received intrathecal urokinase [23]. Clinical resolution was achieved in 29/32 cases (90.6%), while 2 (6.3%) experienced recurrence [13]. No infections or catheter obstructions were reported.
Among IVH patients with available data (n = 39), intraventricular catheter placement was reported in 5 cases. Freehand placement at Kocher’s point was used in 4 (10.3%) [4, 5, 21, 25], while 2 patients (5.1%) had catheters inserted through an abscess cavity [10, 27]. Treatment duration, when reported, ranged from 4 to 11.5 days, and irrigation rates varied between 30 and 120 mL/h [7, 14, 17]. Intrathecal thrombolytics were administered in 11 patients (28.2%): tPA in 9 and nicardipine in 2 [1, 2, 9–11, 18, 21–23, 25]. Outcomes included complete resolution in 13 cases (33.3%), clinical improvement in 3 (7.7%), and death in 1 (2.6%). Reported complications comprised catheter obstruction in 8 (20.5%) and infection in 2 (5.1%) [9, 11, 13, 22].
Among ventriculitis patients (n = 7; 4.7%), catheter placement was intraventricular in 5 cases (71.4%) and through an abscess cavity in 1 (14.3%) [2, 4, 21, 26]. Techniques included freehand burr-hole placement (n = 3) and frameless stereotactic guidance (n = 1). Intrathecal therapy was administered in all cases, most frequently vancomycin (3 patients; 42.9%), followed by cefepime (1; 14.3%), gentamicin (1; 14.3%), and urokinase (1; 14.3%) [2, 4, 21, 26]. Outcomes included resolution in 3 cases (42.9%), improvement in 2 (28.6%), and death in 2 (28.6%). Reported complications comprised catheter obstruction (3; 42.9%), subdural fluid collection (1; 14.3%), CSF leak (1; 14.3%), and hydrocephalus (1; 14.3%) [2, 4, 21, 26].
Case series
A total of 13 patients were treated with IRRAflow in our institutional cohort. The median age was 69 years (range 37–89), with 8 males and 5 females (Table 3). Pathologies included IVH (n = 6), CSDH (n = 4), and ventriculitis (n = 3). Among ventriculitis cases, two were secondary to ruptured thalamic abscesses, while one developed after external ventricular drainage for IVH and was microbiologically confirmed as Acinetobacter baumannii. Etiologies of IVH included spontaneous hemorrhage in deep structures, post-endoscopic complications, and one neoplastic case. All CSDH cases were post-traumatic, unilateral, and had a hematoma thickness ranging from 18 to 23 mm.
All patients underwent IRRAflow catheter placement according to pathology-specific protocols (Table 4). For ventriculitis (n = 3), frameless stereotactic implantation into the abscess cavity was performed in two patients, while one underwent freehand intraventricular placement via Kocher’s point. All three received intrathecal antibiotics (gentamicin or colistin), with urokinase co-administered in one case.
For IVH, catheter tip positioning varied between standard intraventricular placement and trajectories through the hematoma cavity, the latter usually guided by neuronavigation-assisted minicraniotomy. Therapy duration ranged from 9 to 14 days, and urokinase was administered in three cases.
CSDH patients (n = 4) were treated by subdural freehand single burr-hole placement, without intrathecal therapy, with treatment duration ranging from 2 to 4 days.
At discharge, favorable outcomes (modified Rankin Scale [mRS] 1–2) were observed in 6/13 patients (46%), especially in those with CSDH and ventriculitis. Three patients (23%) had severe disability or death (mRS 6), predominantly in the IVH group. Reported complications included post-urokinase hemorrhage (1 case), CSF infection (1), and catheter occlusion (1). No patient required ventriculoperitoneal shunting during follow-up (Table 5).