Several major developments have occurred in 2005 with regards to routine evaluation of shunt malfunction and "non-invasive" shunt assessment.
The most important discovery occurred when we successfully corroborated DiaCeph "non-invasive" shunt assessment data in TANDEM with a single in-office ICP manometer assessment. This new tandem application elevates the reliability and utility of both methods of CNS shunt assessment.
Field experts would agree that perhaps the most useful diagnostic exam a neurosurgeon can undertake for assessment of shunt malfunction and physiologic pressure setting (programmable shunts) is the in-office ICP tap with manometer readings in the supine and upright postures. But, it is not widely used today because of the fear of several risks which we explain below.
First, there is concern of possible injury to the shunt reservoir itself, followed by a slight risk of infection to the patient. Next, the intermittence that occurs with shunt malfunction, and the disappointment factor and significance that a "single measurement" in time might offer, along with the absence of other diagnostic documentation with respect to earlier incidents reported by the patient - has all led to neurosurgeons shying away from performing in-office ICP taps.
Despite the continued assurances from shunt manufacturers that the integrity of today's shunts and reservoirs are designed to withstand repeated needle insertions, many neurosurgeons still remain reluctant to regularly tap the shunt, and primarily when considering a high likelihood of shunt revision. Nuclear medicine isotope scans for shunt patency and CSF shunt clearance also require a needle insertion, and similarly, are carefully used. The alternative has been the more costly and invasive 48-hour in-hospital monitoring, which is seldom used.
In October 2005, we pioneered a new Tandem Protocol which uses the DiaCeph Test to acquire days/weeks/months of 24/7 shunt data, and compare and corroborate it with a single in-office ICP manometer reading in the upright and supine postures. It is a significant development because it raises both test's reliability by comparing acquired DiaCeph data to widely recognized invasive shunt tap/ICP measurements. We successfully corroborated months of DiaCeph data monitoring with ICP manometer readings in the supine and upright postures. This tandem protocol significantly boosts DiaCeph's efficacy in 24/7 home monitoring, that until now, was only possible via 48 hour ICU hospitalization monitoring.
This protocol validates the "accuracy" and "correct patient use" of the DiaCeph Test. One in-office ICP measurement can "validate" weeks/ months of critical 24/7 DiaCeph monitoring, and help the patient and family better realize its benefits. The DiaCeph Test already has a built-in logic processor to identify and resolve any "erroneous data" that could be mistakenly entered by a patient, guardian, or family member. Matching like day/time/complaint DiaCeph data to in-office manometer readings elevates DiaCeph's efficacy, and corroborates use of the ICP tap exam.
This new protocol further helps resolve the existing costs and risks associated with when and how often to tap a shunt, albeit in-office ICP measurement or isotope imaging. Additionally, it broadens the neurosurgeon's diagnostic options, lessens their reliance on CT/MRI imaging, and minimizes unnecessary shunt revisions and in-office re-programming of shunts. This tandem protocol enables the DiaCeph Test to become widely used for routine 24/7 home assessment of shunt performance, valve pressure matching, and acquiring of diagnostic data for shunt malfunction. The DiaCeph device can be carried with the patient just about anywhere, with testing performed on a preset schedule, or in the event that a shunt related incident is suspected. You can read more on this new tandem protocol in our paper, Shunt Selection Model, and on the DiaCeph Patent page.