Treatment of Normal Pressure Hydrocephalus
Ventriculoperitoneal (VP) shunt placement is the primary treatment for normal pressure hydrocephalus, resulting in clinical improvement in 70-90% of patients and representing the only effective intervention to prevent progression to nursing care dependence. 1, 2
Surgical Treatment Options
VP Shunt as First-Line Therapy
VP shunt insertion is indicated for NPH patients presenting with the classic triad of gait disturbance, cognitive decline, and urinary incontinence, with documented improvement rates of 91.2% at 12 months. 3
Modern shunt therapy with programmable valves demonstrates significant and lasting improvement across all symptoms, with gait showing the most sustained benefit over long-term follow-up (>10 years). 4
At 5-year follow-up, approximately 40% of patients maintain improvement in gait and reaction time, though cognitive benefits decline more substantially over time. 5
Younger patients (<75 years) achieve better outcomes, with 64% showing improvement compared to only 11% in patients >75 years, emphasizing the importance of early intervention. 5
Endoscopic Third Ventriculostomy (ETV) as Alternative
ETV has emerged as an alternative to VP shunts in selected NPH patients, though its role remains limited compared to obstructive hydrocephalus. 1
When adjusted for patient age and etiology, ETV demonstrates higher early failure rates than shunts but lower failure rates after 3 months. 1
Both CSF shunts and ETV show equivalent overall outcomes in many clinical scenarios (Level II evidence), though VP shunts remain the standard for communicating hydrocephalus like NPH. 1
Pre-Surgical Evaluation and Patient Selection
Diagnostic Confirmation
MRI with contrast is required to evaluate ventriculomegaly and exclude other causes before proceeding with surgical intervention. 1
Semi-invasive diagnostic procedures (lumbar drain trial or high-volume lumbar puncture) are recommended when clinical findings and imaging alone are insufficient, as 75% of NPH patients have coexisting neurodegenerative disorders. 2
Predictive Testing Protocol
Standardized assessment using validated tests before and after temporary CSF diversion (lumbar drain) identifies surgical candidates with 89.6% reporting symptomatic improvement at 6 weeks post-shunt. 6
Specific validated tests include: Timed "Up & Go", Tinetti Gait and Balance Assessment, Berg Balance Scale, Mini Mental Status Exam, Trail Making Test Part B, and Rey Auditory and Visual Learning Test. 6
Mean Tinetti score improvement after lumbar drain significantly predicts shunt success (4.27 vs -0.48 in non-responders, P<0.001). 6
Post-Operative Management
Valve Adjustment and Monitoring
Programmable valves allow non-invasive pressure adjustments, with 40% of patients requiring valve pressure changes during follow-up to optimize symptom control. 4
Otoacoustic emission testing provides noninvasive monitoring of shunt function, with phase shifts becoming negative after successful surgery and returning positive with malfunction. 7
Revision Requirements
Approximately 20% of patients require surgical revision for shunt malfunction within long-term follow-up, with 93.3% of revisions resulting in clinical improvement. 4
Strict follow-up is necessary for early diagnosis of shunt malfunction or need for valve adjustment to maintain therapeutic benefit. 4
Common Pitfalls and Caveats
What NOT to Do
Serial lumbar punctures should NOT be used as definitive treatment (Level I evidence), as they provide only temporary relief without addressing the underlying pathophysiology. 1
Delaying surgical intervention leads to disease progression, with approximately 80% of NPH cases remaining unrecognized and untreated, ultimately resulting in nursing care dependence. 2
Complications to Monitor
Subdural fluid collections occur in 18% of patients on postoperative imaging, though most are asymptomatic. 6
Other complications include seizures, intracerebral hemorrhage, and stroke, occurring in approximately 6% of cases. 6
Long-term symptom recurrence affects approximately 45% of patients at 1-year follow-up, necessitating ongoing monitoring and potential valve adjustments. 6
Timing Considerations
Early surgical intervention is critical, particularly in patients <75 years, as outcomes deteriorate significantly with advancing age and disease progression. 5
High mortality from comorbidity (37% at 5 years) and declining general health emphasize the importance of treating NPH before patients become too frail for surgery. 5