Role of Radiological Parameters in Predicting Overall Shunt Outcome After Ventriculoperitoneal Shunt Insertion in Pediatric Patients With Obstructive Hydrocephalus

Devi Prasad Patra, MD, MCh; Shyamal C. Bir, MD, PhD; Tanmoy K. Maiti, MD, MCh; Piyush Kalakoti, MD; Hugo Cuellar, MD, PhD; Bharat Guthikonda, MD; Hai Sun, MD, PhD; Christina Notarianni, MD; Anil Nanda, MD, MPH

Disclosures

Neurosurg Focus. 2016;41(5):e4 

In This Article

Methods

This retrospective study included all pediatric patients with an age < 18 years who had undergone VP shunt surgery for obstructive hydrocephalus at our institute between January 2004 and January 2016. Clinical and radiological data including follow-up were reviewed from hospital records after we had obtained local institutional review board approval and complied with Health Insurance Portability and Accountability Act (HIPAA) regulations.

Radiological Data Acquisition

Preoperative and postoperative CT or MRI studies (MRI was preferred over CT) were reviewed, and measurements were taken using the hospital-based picture archiving and communication system (PACS). Availability of paired preoperative and postoperative images was a significant concern, and unavailability led to exclusion from analysis. Patients who underwent surgery based on cranial ultrasound were excluded from the study. Measurements were taken using the "measurement tool" of the PACS 4.0 software (Centricity Radiology RA1000, GE Healthcare). Linear indices were calculated per the formulas given in Table 1 and Fig. 1. Other radiological factors were also noted, including bi- or triventriculomegaly, ventricular symmetry (right-left symmetry), and the presence or absence of periventricular lucency (PVL). Ventricular asymmetry was documented when the difference in the diameters of both sides of the ventricles was more than 2 mm.[5]

Figure 1.

Linear measurements in the cranial CT. a = maximal diameter of the frontal horn; b = maximal cranial diameter at the level of the frontal horn; c = maximal diameter of the occipital horn; d = maximal cranial diameter at the level of the occipital horn; e = maximal cranial diameter (biparietal diameter).

Clinical Data Acquisition

The primary clinical outcomes that were reviewed included the need for shunt revision, time interval to first shunt revision after primary surgery, total number of shunt revisions, and revision-free survival. The latter was calculated based on the interval between primary surgery and the first shunt revision. In patients who did not require shunt revision, it was calculated based on the maximum available follow-up time. These outcomes were correlated with the preoperative radiological parameters and indices.

Statistical Methods

Statistical analysis was done using SPSS software (version 24.0, IBM Corp). The mean values of the linear indices and ratios were compared with the different outcome groups by using an independent sample t-test. A comparison of the different groups was done using the chi-square test and ANOVA. A multivariate analysis was conducted for all outcomes, considering all radiological indices as covariates. Shunt revision–free survival was calculated and plotted using the Kaplan-Meier method. Mean values were expressed with the standard error of the mean. A p value < 0.05 was considered statistically significant.

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