Idiopathic normal pressure hydrocephalus outcome
Patients often present to the neurosurgeon frustrated and desperate after a long preoperative course. It is important to acknowledge the uncertainty regarding Idiopathic normal pressure hydrocephalus diagnosis and response to shunting when counseling patients. Comorbid conditions interfere with the ability to assess progression of iNPH and the effectiveness of the shunt. Patient caregivers play a large role in decision-making and clinical course, and should be included when counseling patients 1).
A 2001 meta-analysis of outcomes reported the Idiopathic normal pressure hydrocephalus treatment to have a 29% rate of significant improvement and a 6% significant complication rate 2).
A study in 2005 revealed greater improvements, with 75% of patients (n = 132) seeing postoperative improvements within 24 months of surgery 3), 68% of patients experiencing “very good” or “good” outcomes in a prospective study 4), and 69%–84% of patients seeing improvements by 1 year after surgery in a prospective multicenter study 5).
Studies that have established fixed protocols for follow-up have shown that short- and long-term periods after shunting are determined by many factors. Whereas short-term results were more likely to be influenced by shunt-associated risks, long-term results were independent of factors inherent to the shunt procedure and shunt complications, i.e., death and morbidity related to concomitant cerebrovascular and vascular diseases 6).
In 2013 a total of 64 studies of 3,063 patients were reviewed. Positive improvement following shunt insertion was reported in an average of 71 % of patients with an average 1 % mortality. Results from studies published in the last 5 years showed 82 % improvement following shunt insertion, mortality of 0.2 %, and combined common complications rate of 8.2 % 7).
Analysis of the efficacy of shunts for possible iNPH conducted in Japan indicated a significant improvement in the mRS grade between baseline and outcome within 1 year, regardless of the surgical technique, and shunt intervention was found to be effective 8).
Clinically, patients presenting with early or severe dementia have worse outcome, while those with a primary gait disturbance feature have better results 9) 10)
A growing body of evidence suggests that longer durations of preoperative symptoms may correlate with worse postoperative outcomes following cerebrospinal fluid diversion for treatment of idiopathic normal pressure hydrocephalus (iNPH).
Outcomes after ventriculoperitoneal shunting for idiopathic normal pressure hydrocephalus (INPH) are variable due to a lack of reliable, quantitative outcome data and inconsistent methods of selecting shunt candidates.
Clinical improvement of patients with iNPH can be sustained for 5-7 years in some patients, even if shunt revision surgery is needed multiple times. With earlier diagnosis and treatment and the increasing lifespan of the ageing population, the need for long-term follow-up after shunt surgery may be greater than it was in the past. Monitoring, identification and treatment of shunt obstruction is a key management principle 11).
Gait and Incontinence
Postoperative improvement of Gait and Urinary incontinence is obtained at an early stage 12) 13). In contrast, Dementia tends to improve gradually from after the third postoperative month. The family satisfaction increases as the symptom of Dementia improve. The satisfaction of the medical personnel tends to remain high after the first postoperative month 14).
Independent predictors of improvement are the presence of gait impairment as the dominant symptom and shorter duration of symptoms 15).
Shunt operations reduced the caregiver burden of iNPH patients 16). 17).
Thirty-seven patients (median age 70 years, range 50-89 years) with Idiopathic normal pressure hydrocephalus were evaluated before and 6 months after surgery. Symptoms and signs were assessed by the iNPH scale, activities of daily living (ADL) with the Functional Independence Measure (FIM) and Assessment of Motor and Process Skills (AMPS), autonomy and participation with Impact on Participation and Autonomy (IPA), and caregiver burden with the Caregiver Burden Scale (CBS). HRQOL was evaluated with the EQ-5D (EuroQol Group-5 Dimension health survey).
Twenty-four patients (65%) improved clinically (iNPH scale score) and 31 (86%) improved their HRQOL after surgery, almost to the same level as found in the normal population. The patients became more independent in physical and cognition, and participation and autonomy improved. The caregiver burden was decreased among caregivers to male patients but remained unchanged on the overall group level. After shunt surgery, patients with iNPH showed improvement in most aspects of social life, they became more independent, and their quality of life returned to nearly normal 18).