Diagnosis and management of idiopathic normal-pressure hydrocephalus: a prospective study in 151 patients.
OBJECTIVE
The diagnosis and management of idiopathic normal-pressure hydrocephalus (NPH) remains controversial, particularly in selecting patients for shunt insertion. The use of clinical criteria coupled with imaging studies has limited effectiveness in predicting shunt success. The goal of this prospective study was to assess the usefulness of clinical criteria together with brain imaging studies, resistance testing, and external lumbar drainage (ELD) of cerebrospinal fluid (CSF) in determining which patients would most likely benefit from shunt surgery.


METHODS
One hundred fifty-one patients considered at risk for idiopathic NPH were prospectively studied according to a fixed management protocol. The clinical criterion for idiopathic NPH included ventriculomegaly demonstrated on computerized tomography or magnetic resonance imaging studies combined with gait disturbance, incontinence, and dementia. Subsequently, all patients with a clinical diagnosis of idiopathic NPH underwent a lumbar tap for the measurement of CSF resistance. Following this procedure, patients were admitted to the hospital neurosurgical service for a 3-day ELD of CSF. Video assessment of gait and neuropsychological testing was conducted before and after drainage. A shunt procedure was then offered to patients who had experienced clinical improvement from ELD. Shunt outcome was assessed at 1 year postsurgery.


CONCLUSIONS
Data in this report affirm that gait improvement immediately following ELD is the best prognostic indicator of a positive shunt outcome, with an accuracy of prediction greater than 90%. Furthermore, bolus resistance testing is useful as a prognostic tool, does not require hospitalization, can be performed in an outpatient setting, and has an overall accuracy of 72% in predicting successful ELD outcome. Equally important is the finding that improvement with shunt surgery is independent of age up to the ninth decade of life in patients who improved on ELD.
Marmarou
Anthony
A
Department of Neurosurgery, Virginia Commonwealth University Medical Center, Richmond, Virginia 23219-0449, USA. marmarou@hsc.vcu.edu
Young
Harold F
HF
Aygok
Gunes A
GA
Sawauchi
Satoshi
S
Tsuji
Osamu
O
Yamamoto
Takuji
T
Dunbar
Jana
J
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002557:Cerebrospinal Fluid Shunts; D003071:Cognition; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000175:diagnosis* / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010351:Patient Discharge; D011183:Postoperative Complications; D011300:Preoperative Care; D011446:Prospective Studies; D012720:Severity of Illness Index; D013129:Spinal Puncture; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014743:Videotape Recording