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History of Neurostimulation:  Part II
Implanted Neuroaugmentive Devices
 

The very first implanted electronic neuroaugmentive device created to treat disease (tremor) was fabricated in 1964 by Drs. E.A. Spiegel , H.T. Wycis, and associates in the Department of Neurosurgery at Temple University Hospital, Philadelphia.  Their work did not receive much notice or recognition at the time because their devices did not result in patient implantation.  As their associate Charles Zanes noted "since it was ahead of it’s time there was reluctance on the part of the clinicians to use it."
 
This reluctance was not shared by neurosurgeon C. Norman Shealy who in 1967 implanted the first neuroaugmentive device for the relief of intractable pain in a terminally ill cancer patient (Shealy CN, Mortimer JT, Reswick JB: Electrical Inhibition of Pain by Stimulation of the Dorsal Columns, Anesth. Analg curr. Res. 46:299-304, 489-491, 1967).  By 1970 six patients had undergone this treatment by Shealy and associates.
Shealy's implanted spinal neurostimulators (which he termed "dorsal column stimulators") were intended for pain relief, are credited as being the definitive pioneering effort in this field.  Unfortunately for Shealy his great expectations were marred by some serious complications associated with these new implanted spinal neurostimulator devices. The primary problem was not the device itself but the decision to place the spinal electrode directly within the subarachnoid space.   The complications relating to this (noted below) doomed the initial dorsal column stimulators:
 
Direct compression of the spinal cord producing paraplegia

Cerebro-spinal fluid leakage through dural incision and secondary meningitis

Progressive arachnoiditis resulting from electrode presence in the subarachnoid space
 
Because of these severe complications the first generation of spinal neurostimulators fell into disrepute. Fortunately, the development of an intradural electrode placement technique demonstrated that a microsurgically created pocket could safely maintain the electrode in a stable position outside of the subarachnoid space.
 This "intradural" placement between layers of the dura (as shown above) alleviated most of the serious complications and led to the next step forward; that of epidural electrode placement.  The less serious complications were then focused on.

The initial hopes associated with the utilization of implanted devices to augment function of the nervous system have continued to be validated and the contributions of neuroaugmentation have continued to be more important.  It may be difficult to believe today but in the 1970's there were many in health care who were against placing electronic devices within the human body.  This resistance rapidly disappeared due to the continuing success of cardiac pacemakers (also neuroaugmentive devices) which were pioneered by Medtronic Inc. in Minneapolis at that time.

In 1974 a joint effort was initiated by Dr. Lauren Leslie, the Director of the Sister Kenny Rehabilitation Institute, Earl Bakken, founder of Medtronic, Inc., Charles Ray, director of Neurologic research at Medtronic, and the Editor who was, at that time, an Associate Professor of Neurosurgery at Temple University Health Sciences Center, Philadelphia, to establish a rehabilitation unit at Sister Kenny Institute in Minneapolis.  It was felt that the potential to rehabilitate incapacitated patients with problems then considered to be "untreatable" was good.  The term "neuroaugmentive surgery" was coined and a Department of Neuroaugmentive Surgery  was then established at the Sister Kenny Rehabilitation Institute with the Editor as program director. 

The purpose of this clinical unit was to apply, the then-existing state-of the-art in neurostimulation to the rehabilitation of disabled patients.   

The major advantage of the new discipline of neuroaugmentation was its utilization of the intact nervous system.  By enhancing nervous system function rather than destroying it by the procedures listed below (common practices at that time) a new paradigm in therapy was begun.
 

Pre-frontal Lobotomy
    Cortical Topectomy
    Thalamotomy
    Spinal Tractotomy
Neurectomy
In 1974, when the Department of Neuroaugmentive Surgery opened at the Sister Kenny Rehabilitation Institute the field of neurostimulation encompassed the following disciplines:

Brain Neurostimulation
    Pain Relief
    Tremor Control 
    Treatment of Cerebral Palsy 
Spinal Neurostimulation
    Pain Relief
    Peripheral Vascular Flow Enhancement
Peripheral Nerve Stimulation 
    Pain Relief
    Phrenic Nerve Pacing 
Tissue Growth Stimulation
Bone Growth Stimulation
It soon became evident to neuroaugmentive surgeons that although many of the implanted devices had some, but often limited, value the devices for which the greatest need existed, developed for the relief of intractable pain.  The single largest largest population of individuals suffering with chronic intractable pain were those who had not done well following one or more spinal surgeries (the so-called "failed back surgery syndrome)" and those afflicted with adhesive arachnoiditis following the introduction of neurotoxic materials into the subarachnoid space.
 
The neurophysiology of the mechanisms by which neurostimulation influenced the nervous system, with particular focus on pain relief has represented a fascinating chronicle.  The first manufacturers of implantable devices designed for the relief of pain in the United States starting in the 1970s were Medtronic, Inc., StimTech, and Avery Laboratories.
 
Implanted neurostimulators have existed for only about four decades.  The Burton Experience has involved the application of well over a thousand neurostimulator devices, for the relief of intractable pain, during that period of time.  Implanted spinal neurostimulators have come a long way since the 1970s when the Editor was told by an operating room nurse that she would not assist in the procedure because it was "against god" to do so. 

In general, when applied by knowledgeable and experienced clinicians in combination with appropriate patient screening one should be able to expect a 65% good long-term result.  Neuroaugmentive systems are now standard devices and are used throughout the world (as are cardiac pacemakers).  Unfortunately, the success of theses devices has also created considerable abuse.  Click here for further information on the use of neuroaugmentive devices for relief of pain.