High prevalence of cervical myelopathy in patients with idiopathic normal pressure hydrocephalus
Introduction
Idiopathic normal pressure hydrocephalus (iNPH) is a progressive neurological disorder characterized by gait abnormalities and imbalance, cognitive decline, urinary incontinence, ventriculomegaly, and normal cerebrospinal fluid (CSF) pressure [1,2]. The reported incidence of iNPH is 0.5–5.5 per 100,000 people per year, with the prevalence of iNPH increasing exponentially as a function of age [[3], [4], [5]]. Idiopathic NPH often poses a diagnostic dilemma since there can be considerable overlap in the symptomatology between iNPH and several neurodegenerative diseases including Parkinson’s and Alzheimer’s disease [6,7], and the cardinal symptoms may be associated with aging as well [8]. Therefore diagnosis relies on response to high volume lumbar tap or extended lumbar drainage trial, in addition to radiographic evidence of ventriculomegaly [9]. Treatment for iNPH involves CSF diversion via shunting, which is most effective in ameliorating gait dysfunction, although 15–20 % of patients fail to report full resolution of gait abnormalities 3 years after shunting [10,11].
Cervical spondylotic myelopathy is a progressive degenerative process in which compression of the cervical spinal cord causes gait disturbances and imbalance, dexterity loss and weakness of the hands, and urinary dysfunction at late stages [12,13]. Like iNPH, the incidence and prevalence of cervical myelopathy increase with age and the mainstay of treatment is by surgical decompression of the cervical spinal cord, either from an anterior or posterior approach [13,14]. Thus, iNPH and cervical myelopathy may both present with progressive gait impairment and urinary symptoms, particularly in the elderly. Given the overlapping clinical presentation between iNPH and cervical myelopathy and the relatively high percentage of patients with persistent gait disturbances despite shunting, the objective of this study was to investigate the prevalence of cervical myelopathy in patients with iNPH.
Section snippets
Patient selection and variables of interest
This study was approved by the institutional review board (IRB no. 19-000836). A consecutive series of 52 patients who underwent ventriculoperitoneal (VP) shunt placement for iNPH over an 18 month period, between December 1, 2017, and June 30, 2019, by the senior author at a single institution were included in the analysis. All patients had an MRI of the cervical spine 2 years before or after of shunt placement. Electronic medical records were reviewed retrospectively. Basic demographic
Results
Among these 52 patients, there was roughly a 3:2 male to female ratio with 30 males and 22 females (Table 1). The average age of the cohort was 75.2 ± 7.3 years, and the average BMI was 30.0 ± 4.3 kg/m2. Nearly 70 % of the overall cohort were former or current smokers. One hundred percent of patients presented with gait instability, 81 % with urinary incontinence, and 88 % with cognitive decline. In total, 36 of 52 patients (69 %) were found to have DESH.
There were 13 patients (25 %) with grade
Discussion
In this study, we retrospectively reviewed iNPH patients who underwent VP shunting at a single institution by a single surgeon to assess the prevalence of cervical myelopathy in this population. Of 52 iNPH patients, 17 % of patients had grade 2 or 3 spinal stenosis and underwent surgical treatment for both myelopathy and iNPH. All patients in this study presented with gait disturbance. The incidence of cognitive dysfunction and response to lumbar tap test were independent of the degree of
Conclusion
Due to high coincidence of iNPH and cervical myelopathy reported here, a screening MRI of the cervical spine could be considered in all patients with suspected iNPH, though in this study, only those with upper motor neuron findings on clinical examination required surgical intervention. Future studies with larger sample sizes are clearly warranted to better understand the unique clinical presentation of patients with iNPH and concurrent cervical myelopathy. Interestingly, there was an
Disclosure of funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
CRediT authorship contribution statement
Ryan M. Naylor: Investigation, Data curation, Writing - original draft, Writing - review & editing. Karina A. Lenartowicz: Data curation, Writing - original draft, Writing - review & editing. Jonathan Graff-Radford: Conceptualization, Methodology, Writing - original draft, Writing - review & editing, Supervision. David T. Jones: Conceptualization, Methodology, Writing - original draft, Writing - review & editing, Supervision. Jeremy K. Cutsforth-Gregory: Conceptualization, Methodology, Writing
Declaration of Competing Interest
None.
References (27)
- et al.
The special clinical problem of symptomatic hydrocephalus with normal cerebrospinal fluid pressure. Observations on cerebrospinal fluid hydrodynamics
J. Neurol. Sci.
(1965) - et al.
Incidence, comorbidities, and mortality in idiopathic normal pressure hydrocephalus
World Neurosurg.
(2018) - et al.
Cervical spondylotic myelopathy
Neurol. Clin.
(2013) - et al.
Symptomatic occult hydrocephalus with "normal" cerebrospinal-fluid pressure. A treatable syndrome
N. Engl. J. Med.
(1965) - et al.
Prevalence of idiopathic normal pressure hydrocephalus: a prospective, population-based study
PLoS One
(2019) - et al.
Prevalence of idiopathic normal-pressure hydrocephalus
Neurology
(2014) - et al.
Parkinsonian symptoms in normal pressure hydrocephalus: a population-based study
J. Neurol.
(2017) - et al.
Differentiating shunt-responsive normal pressure hydrocephalus from Alzheimer disease and normal aging: pilot study using automated MRI brain tissue segmentation
J. Neurol.
(2014) - et al.
Normal pressure hydrocephalus
Continuum (Minneap Minn)
(2019) - et al.
Normal pressure hydrocephalus: diagnosis and treatment
Curr. Neurol. Neurosci. Rep.
(2008)
Outcomes and complications of different surgical treatments for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis
J. Neurosurg.
Normal pressure hydrocephalus: long-term outcome after shunt surgery
J. Neurol. Neurosurg. Psychiatry
Cervical spondylotic myelopathy: a brief review of its pathophysiology, clinical course, and diagnosis
Neurosurgery
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These authors contributed equally.