Turkish Neurosurgery
Sagittal Spinal Deformity in Patients with Idiopathic Normal Pressure Hydrocephalus
Karina Lenartowicz1, Ryan Naylor2, Anthony Mikula2, Jonathan Graff-Radford3, David Jones3, Jeremy Cutsforth-Gregory3, Niell Graff-Radford4, Jeremy Fogelson2, Benjamin Elder2
1Mayo Clinic, School of Medicine, Rochester/MN,
2Mayo Clinic, Department of Neurological Surgery, Rochester/MN,
3Mayo Clinic, Department of Neurology, Rochester/MN,
4Mayo Clinic, Department of Neurology, Jacksonville/FL,
5Mayo Clinic, Department of Orthopedic Surgery, Rochester/MN,
6Mayo Clinic, Department of Radiology, Rochester/MN,
7Mayo Clinic, Department of Biomedical Engineering, Rochester/MN,
DOI: 10.5137/1019-5149.JTN.36555-22.3

Aim:Idiopathic normal pressure hydrocephalus (iNPH) is characterized by ostural instability, often with a forward leaning posture. However, the presence of concomitant spinal sagittal plane deformity and spinopelvic alignment and have not been studied in this population. The objective of this study was to measure the baseline spinopelvic parameters and characterize the sagittal, and coronal plane deformities in patients with iNPH.Material and Methods:We analyzed a series of patients at one academic institution who underwent ventriculoperitoneal shunting for iNPH with pre-shunt standing full length x-rays. The series of patients was enrolled consecutively to minimize selection bias. We quantified comorbid sagittal plane spinal deformity based on the Scoliosis Research Society-Schwab classification system by assessing pelvic incidence and lumbar lordosis mismatch (PI-LL), pelvic tilt (PT), and sagittal vertical axis (SVA).Results:Seventeen patients (59% male) were included in this study. Mean (± standard deviation) age was 74 ± 5.3 years with a body mass index (BMI) of 30 ± 4.5 kg/m2. Six patients (35%) had marked sagittal plane spinal deformity by at least one parameter: five (29%) had greater than 20˚ PI-LL mismatch, three (18%) had >9.5 cm SVA, and one (6%) had PT greater than30˚. Additionally, the thoracic kyphosis exceeded the lumbar lordosis in nine patients (53%).Conclusion:Positive sagittal balance, with thoracic kyphosis exceeding lumbar lordosis, is common in iNPH patients. This may lead to postural instability, especially in patients whose gait does not improve following shunting. These patients may warrant further investigation and workup, including full length standing x-rays. Future studies should assess for improvement in the sagittal plane parameters following shunt placement.

Corresponding author : Karina Lenartowicz