Outcome
"The external lumbar drainage test is the best predictor of outcome for NPH treatment"
Information
One of the most important questions you may have is exactly how successful is treatment of NPH?
When NPH was first described, essentially everyone received a CSF shunt. However, the success rate of this approach was only in the region of 50-60%. This was largely because, as described, only a certain proportion of people with NPH will benefit from a CSF shunt, and this low success rate reflects the inclusion of these people. This is the purpose of the External Lumbar Drainage test. Other more recent studies looking at outcome of CSF shunting in NPH have found improvement rates of 80-90%.
In an analysis of 151 of our most recently assessed cases of NPH, 100patients (66%) showed improvement in symptoms following external lumbar drainage. Of these 100 patients 84 were selected for shunting, and in 76 patients, (90%) their symptoms remained markedly improved for up to one year after the procedure (the duration of assessment). In the 8 people not given a shunt, their symptoms either remained the same or worsened.
Of these same 151 patients, 51 (34%) showed no improvement with external lumbar drainage. Eighteen of these patients were given shunts anyway (for other reasons), and 33 were left untreated. Of the 18 patients, 4 show slight improvement. The remaining 33 patients either remained the same or worsened.
In summary therefore the external lumbar drainage test (in the hands of experienced assessors) is the best predictor of outcome for NPH treatment and has the sensitivity of 90 percent.
Shunt complications in patients with idiopathic NPH
| Complication rate | Total Number of Cases |
|---|---|
| major (9.8%) | |
infection |
3 |
SDH |
3 |
hygroma |
3 |
sinus thrombosis |
1 |
| minor (13.7%) | |
headache |
5 |
hearing loss |
5 |
double vision |
4 |
* Figure taken from
Anthony Marmarou, Ph.D., Harold F. Young, M.D., Gunes A. Aygok, M.D., Satoshi Sawauchi, M.D., Osamu Tsuji, M.D., Takuji Yamamoto, M.D., and Jana Dunbar, Ph.D., Diagnosis and management of idiopathic normal-pressure hydrocephalus: a prospective study in 151 patients; J Neurosurg 102:987-997, 2005.