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Programming the Codman Hakim Medos Programmable Shunt in NPH and Adult Hydrocephalus

By: Stephen Dolle, Dolle Communications, Inventor of the DiaCeph Test

Codman, a division of Johnson & Johnson, introduced the “Hakim” programmable shunt in 1998, and since that time it has emerged to become the No. 1 selling CNS shunt in the treatment of adult hydrocephalus and NPH (normal pressure hydrocephalus). But, the mystery remains as to how to best determine its best pressure setting for each patient from among its 18 different settings, ranging from 30 to 200 mmH2O. Stories abound on Internet forums from user patients complaining of what are obvious shunt related complaints, yet having no information, test methods, or other resources to let them know whether their Hakim shunt is set to the most optimum setting. I liken it to fine-tuning the amount of daily insulin in an individual with Type-1diabetes.

Like diabetes, hydrocephalus is tricky to treat in that each person has their own unique degree of shunt dependence and internal ventricular to abdominal cavity pressures, through which CSF (cerebral spinal fluid) must flow to maintain a physiologically healthy intracranial pressure (ICP) and blood pressure within the brain. Hydrocephalus is characterized by a person having insufficient CSF clearance in the brain, from one of many causes or etiologies, where the fluid backs up and exerts abnormal and often dangerous pressures on many of the brain’s vital structures. The surgical procedure is rather simple as compared to the seriousness of the problem it is trying to solve. CNS shunts have been used in the U.S. to treat hydrocephalus for more than 50 years, with perhaps as many as 1,000,000 people implanted with them today. Yet, there still is no home test or means available to alert the patient-user when their shunt might not be working correctly, albeit a mismatched setting of a programmable shunt, or a shunt malfunction in progress, the latter being a common occurrence in any CNS shunt.

After being a Codman programmable shunt customer since July 2007, and a not so happy one at times due to the “experimenting” that took place with my neurosurgeon in finding its best setting for me, I eventually figured out an ideal method of programming the Hakim shunt. I’m not suggesting that neurosurgeons throw out the manufacturer’s labeling instructions on finding the best setting. But I can say with confidence that my way is a better method. In 1997, I also pioneered the first ever home shunt test, the DiaCeph Test, to enable shunt users to non-invasively monitor their status, and help make their quality of life more manageable.

The central theme to my method is to get the programmable setting down to as low a setting as tolerable, then gradually raise it upwards in 10 mmH2O increments. Each setting should be evaluated for 4 to 7 days. The goal is to find a setting that provides a tolerable upright flow during the daytime, yet flows well enough at night to accommodate ICP spikes during REM sleep (from too high of a valve setting). In my experience, the latter nighttime performance is more critical than mild daytime overdrainage, as night time ICP spikes tend to create chronic complaints for some 24 -48 hours after they occur. You may have to settle with having one or two night time REM spikes a week, as the best compromise to daytime overdrainage. But again, give more priority to your night time status. It can take up to 4 weeks or more to safely get the programmable shunt down to its lowest tolerable setting following surgery, and another few weeks to find its most optimized setting.  The Hakim is the best shunt on the market when it comes to the availability of physiologic settings. So be committed to spending the time to get it optimized for you.

Another important point I will only touch on here is the percutaneous evaluation (finger pressure) of the shunt (main chamber) to determine whether the valve chamber is open, or closed, and when the patient might be experiencing unexplained complaints. For example, if the patient is experiencing a headache in the daytime while sitting or standing, and the percutaneous finger test indicates the main chamber to be “open,” the finding would suggest a pressure setting that is too low. Conversely, if percutaneous sampling continues to reveal the primary chamber to be closed during periods when headache and other complaints are occurring, this is a pretty clear indication the setting it too high. You should evaluate each setting at least 8 or 10 times over a 4 to 7 day period.

My method of percutaneous sampling is to slowly pinch off the ventricular catheter reservoir (or Rickam chamber) with the index or middle finger of one hand, while slowly depressing the Codman shunt anti-chamber (reservoir) with the index or middle finger of the opposite hand, and observing whether the finger over the shunt reservoir encountered “measureable” resistance. There is a very obvious resistance to finger touching when the shunt valve chamber is “closed,” as opposed to very little resistance when it is “open” and flowing. This evaluation also serves as a crude assessment of shunt patency. But for these purposes, we’re only interested in knowing whether the valve is open or closed during periods of complaints. Conversely, you might want to check the status of the shunt (open vs. closed) on a few occasions when no complaints are present, just to confirm in what position the patient felt better. This method would apply to makes of other programmable shunts, notwithstanding the consideration that must be paid to the differences in pressure setting values and terminology.

With the above information in hand from the patient or family member, the neurosurgeon can then adjust the shunt accordingly to find the most optimized setting for each patient. Of course, it would be extraordinarily beneficial if the patient and family had the DiaCeph Test or a PMR (personal medical record) palm device, or alternately, DiaCeph software embedded into their personal cell phone. The DiaCeph Test is notably different from a PMR in that it is a patented disease management program, designed to address the many unique needs of users with CNS shunts.