Neuroendoscopic Surgery With Ommaya Reservoir Implantation vs. Burr Hole Drainage for Infantile Postmeningitis Subdural Lesions: Superior Efficacy, Critical Impact of Surgical Timing, and Pathogenic Bacteria as Risk Factors for Progression
Conditions: Meningitis
Sponsor: Shengjing Hospital

Study design
This study is a multicenter retrospective cohort study.We included data from IPSFC and IPSE
children under one year of age who underwent surgical treatment at the Nanhu Campus of
Shengjing Hospital Affiliated to China Medical University and the Huaxiang Campus of the
Second Affiliated Hospital of China Medical University between 2010 and 2024. The data
included: basic patient information, present and past medical history, imaging materials,
laboratory results, medical orders, surgical records, and complete 1-year follow-up data. The
objectives of this study were to investigate the association between different surgical intervention
timings and the non-cure rate of IPSSL, compare the efficacy differences between BHID and
neuroendoscopic technique combined with Ommaya reservoir implantation in treating IPSSL, and
analyze the high-risk factors for Stage III IPSFC progression to IPSE. In this study, legal
guardians of all child patients provided written informed consent. This protocol was approved by
the Ethics Review Committee of China Medical University. This study conformed to the Helsinki
Declaration, and all child patient information was de-identified.
All child patients had undergone at least three weeks of standardized anti-infection therapy before
inclusion in this study, including antibiotics (empirical or based on antibiotic susceptibility results)
and appropriate dexamethasone administered intrathecally after lumbar puncture or intravenously.
During conservative treatment, vital signs and neurological signs were closely monitored, with
regular imaging reviews to assess changes in fluid collection thickness and the development of
empyema. Cranial ultrasound was the primary modality, performed at intervals of no more than 3
days, while cranial computed tomography (CT) and MRI were conducted no more than once
weekly.
By integrating imaging findings and clinical manifestations, the inclusion criteria for this study
were determined. Children undergoing surgical treatment should meet at least one imaging
criterion (persistent short-term widening of the subdural space or compression of lateral ventricles;
unilateral fluid collection thickness >1 cm for two consecutive weeks; formation of empyema
abscess wall or mature empyema) and at least two clinical criteria (head circumference growth
rate exceeding normal range or increased fontanelle tension; worsening IPSSL symptoms or
persistent poor infection control; manifestations of intracranial hypertension such as repeated
vomiting or lethargy; frequent neurological abnormalities like epileptic seizures; asymptomatic
cases with fluid/empyema thickness >1 cm for >2 weeks). All IPSFC children undergoing surgical
intervention should have a unilateral fluid collection thickness of at least 1 cm. Asymptomatic
IPSSL children should be primarily managed with non-surgical treatment and under close
monitoring of their condition. The surgical protocols and indications were approved by a
dedicated review committee.
To investigate the association between different surgical timings and the non-cure rate of IPSSL,
all IPSSL children who underwent the same surgical procedure were divided into an acute group
(<14 days), a subacute group (14 to 28 days), and a delayed intervention group (>28 days). The
grouping was based on the duration from the time of initial detection of subdural fluid collection
formation to the day of surgery.The onset of fluid collection is defined as a thickness of > 3 mm in
IPSFC children.Cure was defined as complete resolution of clinical symptoms (fever, headache,

etc.), absence of seizures, normal activity and feeding, normal CSF white blood cell (WBC) count,
protein, and glucose levels with negative pathogen detection, age-appropriate neurological
function at 1 year, sustained stability allowing normal social participation at 2 years, Bayley
Scales of Infant and Toddler Development III score >85 during follow-up, cranial imaging
showing no brain parenchyma compression or new lesions, and no secondary surgical treatment.
Enrolled children not meeting all criteria were defined as non-cured.
To investigate the risk factors for Stage III IPSFC progression to IPSE formation, this study
enrolled not only all IPSE children who underwent surgical treatment but also all children whose
disease had progressed to Stage III IPSFC. The number of days from the first observation of Stage
III IPSFC to IPSE formation was calculated. Potential risk factors considered primarily included:
presence of immunodeficiency, timeliness of treatment, prematurity, days from IBM diagnosis to
progression to Stage III IPSFC, days from Stage I to Stage III IPSFC progression, and pathogenic
agents.
Major exclusion criteria included: subdural fluid collections secondary to viral meningitis;
secondary subdural fluid collections with a confirmed history of craniocerebral trauma; diagnosis
of tuberculous subdural effusion; and presence of intracranial space-occupying lesions.
Study endpoint
To compare the imaging changes between different surgical procedures, we calculated the
thickness of fluid collection or empyema on the day before surgery and seven days after surgery.
The thickest section of the subdural lesion was selected for measurement in CT or MRI. As far as
we know, there is currently a lack of scoring scales for IPSSL-related disease assessment in both
the field of pediatric neurosurgery and pediatric intensive care. To visually demonstrate the
symptomatic improvement in children before and after surgery, we developed a scoring scale
specific to this study (IPSSL-score) to evaluate the severity of IPSSL and the efficacy of surgical
treatment. This scoring scale incorporates the Hines neurological score for infants, intracranial
pressure assessment parameters, inflammatory control status, and neurological function
evaluation.The Hines Neurological Score for Infants is a neurofunctional assessment tool for
neonates to 2-year-old infants, adjusted for infant neurological developmental characteristics
based on the traditional Hines Score. It is used to monitor neurological injury, developmental
abnormalities, or postoperative neurological status, demonstrating high practical value in
perioperative and intensive care settings. The specific scoring criteria for IPSSL-score are
presented in Figure 1. The total score is 20 points, where a lower preoperative score indicates
more severe symptoms and a higher postoperative score suggests better therapeutic efficacy. We
collected IPSSL-score data for all children before surgery and during follow-up at 3 months, 6
months, and 12 months postoperatively. The diagnostic criteria for IPSFC, IPSE, and IBM are
presented in Supplementary 1.
Surgical procedure and treatment process
After successful general anesthesia, the child was placed in the supine position with the head

turned approximately 30 degrees to the opposite side of the surgical site and fixed with a head ring.
A 4-cm curved incision was marked on the forehead. Routine disinfection was performed with
povidone-iodine, followed by draping with sterile towels. After incising the scalp along the
marked line, a scalp retractor was used to retract the scalp, and subcutaneous soft tissues were
dissected to expose the skull. A burr hole was drilled on the skull surface, which was expanded
into an oval shape. The dura mater was suspended outside the bone window. A cruciate incision of
the dura mater revealed subdural lesions (effusion or pus). A drainage tube was carefully inserted
into the subdural space to aspirate approximately 20 ml of fluid. A neuroendoscope was
introduced to remove palpable FIPLs (jelly-like purulent exudate, fibrous cord-like tissues,
inflammatory pseudomembranes, septa, and blood clots) within the abscess cavity. The cavity was
irrigated repeatedly with saline until the effluent became clear. A Medtronic Ommaya reservoir
was connected to the distal drainage tube, inserted approximately 3 cm into the subdural space,
and the reservoir was fixed subcutaneously. Patency was tested. The surgical field was carefully
hemostatic, irrigated with hydrogen peroxide and saline, and the subcutaneous tissue and scalp
were closed in layers. Instruments, gauzes, and cotton pads were counted without discrepancy. The
operation proceeded smoothly. Blood transfusion was administered as indicated by intraoperative
blood gas analysis, and the child was transferred to the pediatric intensive care unit
postoperatively.
The drainage volume for each Ommaya reservoir puncture is controlled within the weight-based
safety range (typically <5 ml/kg) to avoid brain shift caused by rapid decompression. For IPSFC
children, puncture aspiration was performed once daily during the postoperative initial period.
After 7 consecutive days of puncture drainage, whether to continue was assessed based on disease
progression. For IPSE children, twice-daily puncture aspiration was performed initially,
accompanied by specimen testing. This continued until the puncture specimens showed clear
transparency for three consecutive days with normal test results, after which the aspiration
frequency was reduced gradually until discontinuation. Strict aseptic technique must be performed
before each aspiration: local skin disinfection should cover an area with a diameter of ≥5 cm. A
22-gauge scalp needle is used to puncture the reservoir vertically, avoiding oblique puncture to
prevent reservoir damage. The aspiration process should be performed slowly and stopped
immediately when increased resistance is encountered during retraction, to prevent excessive
negative pressure from damaging brain tissue.
For IPSSL children with unidentified pathogens, empirical intra-reservoir injection of vancomycin
in combination with carbapenems via the Ommaya reservoir is initially recommended. Following
bacterial culture and susceptibility testing, sensitive antibiotics should be added based on the
results.For children within 6 months of age, administration is typically once every 24 hours, while
infants older than 6 months may receive the drug once every 12 hours. Adjustments should be
made by referring to the serum drug concentration in puncture drainage specimens and monitoring
based on the drug half-life. The drug should be diluted with normal saline and slowly instilled into
the Ommaya reservoir over more than 5 minutes. After instillation, the catheter should be clamped
for 30 minutes to ensure adequate drug diffusion. Specimens of CSF should be obtained via the
Ommaya reservoir at intervals of no more than 3 days for routine, biochemical, and culture
examinations. IPSFC treatment courses should last at least 1 week, while IPSE treatment courses

should last at least 2 weeks. Treatment may only be considered for discontinuation when CSF tests
are normal and CSF culture is negative for two consecutive times.
Statistical analysis
Continuous variables were presented as mean ± standard error. Repeated measures ANOVA was
used to analyze continuous variables between baseline and outcome, as well as to perform
intergroup comparisons across different groups. Mauchly's test of sphericity was used to determine
whether the sphericity assumption was met across repeated measurements, and the Bonferroni
correction was applied to test for intergroup effects. Multivariate binary logistic regression
analysis was used to analyze the association between different surgical timings and the probability
of non-cure. Multivariate Cox regression analysis was performed to identify the primary risk
factors for progression from stage III IPSFC to IPSE. Statistical significance was defined as p <
0.05. Statistical analyses were performed using SPSS 27.0 software (developed by IBM, Armonk,
NY, USA). Data visualizations were performed using Graphpad Prism (Version 10.1.2).