In 1955, after seven years of trying, John and Mary’s first child was born. The birth of Casey Holter turned John Holter’s life upside-down and changed the course of medical history.
Agonisingly, Casey had spina bifida, a condition where the spine doesn’t fully form and may be dangerously misshapen.
The condition was also causing hydrocephalus, a life-threatening build-up of fluid in the brain.
The fluid that surrounds the brain is called cerebrospinal fluid or CSF and acts as a fluid ‘bath’ which cushions and protects the delicate organ.
It is produced by a structure in the brain stem called the choroid plexus and circulates around the brain before being drained into the blood supply.
If the drainage system is blocked, however, it can lead to a dangerous build-up that can pressure, distort and eventually damage the brain beyond repair. If left untreated, it can be deadly.
In 1955, the only thing keeping Casey Holter alive was a twice daily procedure where a needle was inserted into the fontanelle, the soft spot on a baby’s head, and the excess fluid was removed with a syringe to reduce the pressure.
Eventually, Casey was given an operation by the neurosurgeon Eugene Spitz to insert a ball and spring valve that would, in principle, allow the fluid to drain into the blood supply, without letting anything dangerous from the blood wash back into the CSF.
Unfortunately, the valve was clumsy technology, and when inserted, it irritated Casey’s heart to the point where the young child had a heart attack and suffered permanent brain damage.
John Holter, then working as a technician in a hydraulics factory, asked Eugene Spitz about the details of the procedure. He was surprised that the problem, which seemed to him like a simple hydraulics issue, had not been solved.
He had noticed that when nurses inserted needles into certain types of medical tubing, leaks didn’t occur because the gap was water-tight under low pressure conditions.
But, like a teat on a baby’s bottle, when the pressure was high enough the gap opened and the fluid forced its way through. A perfect valve for releasing built-up CSF and preventing backwash.
Holter went home, sat in his workshop, and constructed the first version that very evening. It was a rough-and-ready rubber-tubing and condom prototype, but it worked.
While the principle was sound, Spitz noted that that the valve must made of a material that wouldn’t irritate the body, as this might cause the same problem that had brain-damaged his son.
Holter contacted Dow Chemical and was advised to use silicone, at the time, a newly developed material.
Holter had created a usable version within months. So quickly, in fact, that his son was still too weak from the last operation to have it installed.
It was first and successfully installed in another child, and then in March 1956, Eugene Spitz installed John Holter’s valve into Casey, successfully treating his hydrocephalus.
Sadly, Casey never fully recovered from his brain damage from the initial operation, and died during an epileptic seizure five years later.
Fittingly, Casey’s legacy is that Holter’s invention, now called the Spitz-Holter shunt, is still in use today.
Holter spent the rest of his life developing valves for medical use and passed away in 2003, having saved the lives of thousands children affected by the same condition as his son.
It is estimated that 15,000 valves based on Holter’s design are installed every year in the United States alone.
John Holter’s remarkable story was retold in a 2001 paper published in the Journal of the American College of Surgeons upon which this article was based.
Link to PubMed entry for Journal of the American College of Surgeons paper.