Peripheral Nerve Stimulation | Spine Surgeon

An Overview of Peripheral Nerve Stimulation

Signals generated through the spinal cord and peripheral nerves in the form of nerve impulses are the information pathways that the brain learns about the environment and reacts to the stimulation (using muscle contraction such as the withdrawal reflex). This pathway includes skin information (touch, temperature and pressure), position sense called proprioception (you know where your arms and legs are in space without looking) and pain (nociception) sensation.

Pain is an obviously important sensation for self-preservation. If you are burning your hand, it behooves you to remove your hand from the fire. If you are wearing through a substantial layer of your skin (a blister), pain is the indication that you need to protect this area of skin from further injury.

There are times that these nerve signal pathways themselves can become damaged. In cases like this, the signals delivered to the brain by the damaged nerve or nerves are false or incorrect. The skin may feel like it is on fire but there is no injury at the site of the pain. Sensation can even be altered at the level of the lower brain. Light touch can be interpreted as severe pain (allodynia). When the nerves themselves are damaged, burning, aching or stabbing pain are the typical descriptions of this type of pain. This is called neuropathic pain. If the pain does not subside after some length of time, this pain is called chronic neuropathic pain.

Chronic neuropathic pain can result from nerve compression (disc herniation, bone spur), from injury to the peripheral nerve (stingers or brachial plexopathy), from infection (shingles, Lyme disease), from autoimmune disorders (Lupus), from metabolic disorders (diabetes) and from trauma.

In cases of chronic neuropathic pain, even though you feel like you want to have these nerves “cut”, cutting these nerves will do nothing to stop the pain. Neuromas (tangles of the ends of these cut nerves) would result, which would create more pain and dysfunction than if the nerves were left alone. The injured nerves also have some intact functions, which need to continue to work. Any severing of this nerve would eliminate these useful functions.

Initial Treatment

Initial treatment to deal with chronic radiculopathy or spinal cord injury induced pain is the use of medications and time. There are occasions that this pain can reduce or extinguish itself over some period of time (see the section on nerve damage and healing to understand nerve recovery). If however this pain does not extinguish itself and becomes intolerable, there is a technique that can help reduce this perceived pain. It is the use of a spinal cord or peripheral nerve stimulator.

How Peripheral Nerve Stimulation Works

The peripheral nerve stimulation system really trades one sensation for another. Think of the “white noise” produced when a TV is turned on but the cable is disconnected. This “noise” is similar to the sensation that one trades for pain reduction. This trading has to do with how the nervous system deals with stimuli of different intensities.

Do you remember the days you were in elementary school on the playground and bruised your forearm? If you rubbed your arm vigorously enough, you would gain temporary relief from that deep pain. This “fast rubbing” of your arm produced a flood of input from the touch receptors. This flooding of the sensory system overwhelmed the pain pathway and the pain “magically” disappeared.

This essentially is the same technique utilized by the spinal cord stimulator. The name for this phenomenon is the Gate Theory of pain. Two scientists, Melzak and Wall were on the short list for the Nobel Prize for this discovery.

The thalamus, located in the lower brain is the switchbox that routes pain signals from the body to the upper portions of the brain. Think of the nerve pathways from the body to the thalamus as pipes carrying messages. The pipes that deliver sensory messages are much larger than the pipes carrying pain messages. If the “pain pipe” delivers its messages unimpeded, the thalamus will “notice pain” and relay it to the upper brain, especially if the sensory pipe is not “flowing with much information”.

The sensory pipe has the capacity for a much larger volume of information than can be delivered by the pain pipe. If this flow of sensory information is large enough, the pressure of this flow will “close a valve”, which cuts off the flow of the pain pipe. The thalamus will then “sense” only sensory information and pain will be eliminated.

The stimulator, through electrical discharges from the implantable leads, creates this sensory overload. The leads of the stimulator however, have to be placed at the correct location for this pain valve to be shut off. This is the precise job of the implant specialist. If the leads are placed correctly, the “pain valve” can be shut off and only “white noise” will be noticed.

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(Please keep reading below for more information on this treatment option.)

Appropriate Application of Stimulation

One of the problems with peripheral nerve stimulation is that this technique has to be used in the appropriate situation. If there is basic surgical pathology causing pain, this disorder should be surgically corrected before consideration of spinal cord stimulation.

Some of the individuals who specialize in implantation of these stimulation devices are not spine surgeons or neurosurgeons. They might not understand the disorder well enough to know that there are surgical solutions to these painful spinal disorders.

I have seen patients with typical pain generators (degenerative spondylolisthesis, spinal stenosis, foraminal stenosis- see website) undergo stimulator placement when the disorder should have been surgically repaired instead. I recommend that if the implanting specialist is an interventional radiologist, anesthesiologist or a physical medicine and rehabilitation doctor (PM&R), that the patient have a consultation with a spine surgeon or neurosurgeon prior to the implantation of the stimulator to make sure the correct decision is being made.

Trial Stimulation

One of the beauties of stimulation is that a trial of stimulation can be performed on an outpatient basis. Leads can be placed percutaneously (through needles) and the wires connected to the electrodes can be left out of the body (temporarily of course). The wires are connected to a small generator that can be adjusted by the patient. If the trial is effective in blocking pain, the permanent implant should be equally as effective.

Implant Failure Over Time

The typical stimulators can be placed along the spinal cord in the epidural space or along a nerve or plexus (junction of a number of nerves). Over time, the stimulators need to be adjusted as in some cases, a fibrous membrane develops which surrounds the leads and “insulates” them. This requires increased signal to overcome the insulator effect of the additional fibrous tissue. Batteries rarely fail but can fail. Infection can occur in these implants requiring removal.

The diagnosis of chronic neuropathy or spinal cord injury that is not surgically fixable is the main indication for spinal cord or peripheral nerve stimulation. Make sure that there are no disorders that can be surgically repaired.

For more resources on chronic neuropathic pain, or to learn more about peripheral nerve stimulation, please contact Dr. Donald Corenman, Vail, Aspen, Denver and Grand Junction, Colorado area spine surgeon and neck doctor.

Donald Corenman, MD, DC

Average rating:

81 reviews

Eric S

Sep 26, 2021

by Eric S on Donald Corenman, MD, DC

Successful pars repair at 46 years old

Back in November of 2018 (at 46 years old) I came from Vancouver BC to have a pars repair done with Dr. Donald Corenman at the Steadman Clinic in Vail Colorado. I'm finally posting this review nearly three years later in late 2021. The reason I waited so long was I wanted to know the final result before I posted my review. Unfortunately in that time Dr. Corenman has retired. Nevertheless, I want to post this review of Dr. Corenman and his staff at the Steadman Clinic in their excellent treatment of my L5 pars interarticularis.

I fractured my pars at age 42 back in 2014 when rolling on the gym floor, and was denied treatment by the Canadian healthcare system, probably due to my age. First my GP told me there was no surgical option for a pars defect, which was quite incorrect! I tried to live with it, but the symptoms worsened (periodic random spine slippage and weeks of resultant pain after just bending over to tie my shoe, so I eventually learned to mostly squat and hardly bend). When I finally consulted with Canadian spine surgeons, I was told they believed my pars defect had been congenital (since birth). This was absurd, considering I had done extreme martial arts (including jiu jitsu) for years prior, as well as 5 years of reinforcing steel full time in my 20s, probably the hardest job on the back you can find. No pars defect like mine would possibly have allowed this--ergo it was impossible that I had had the defect since birth. I did however have an asymptomatic congenital spina bifida occulta that made me more susceptible to a pars fracture. In 2014 in one instant, I went from having the strongest back people I knew said they'd ever seen, to being unable to safely bend over and tie my shoe without a non-negligible risk of my spine slipping randomly (which would lead to weeks of pain after each occurrence). This was due to the unilateral L5 pars defect, otherwise known as spondylolysis. It was when lying in pain on the floor 4 years later after maybe the 6th spine slippage event post injury, that I had had enough, and resolved to have surgery. If Canada's "universal health care" said no, I would make lemonade from lemons, and find the very best surgeon in the world at pars repairs. That was Dr. Donald Corenman. Dr. Corenman back in 2018 ran a website https://neckandback.com/ that dedicated many pages to the science of every aspect of pars repairs, from eligibility (good discs on MRI), to best surgical techniques (minimal open compared to minimally invasive), best imaging to use (i.e., O-Arm with Stealth imaging vs. older fluoroscopy), the ideal amount of BMP to use and why not use too much or too little, and much more, all to do with pars repairs, pages upon pages of his site just on the pars, with scientific references and his own extensive expert opinion. As a health research statistician, I was very impressed with this. It was in stark contrast to the websites of other spine surgeons which barely gave the pars a word or two, focusing almost exclusively on fusions. I had found the best surgeon in the world for pars repairs, and so after Dr. Corenman personally screened my MRI to ensure my discs were healthy, I booked the surgery.

Being 46 years old at the time of surgery in 2018, with a 4-year-old pars fracture from 2014 combined with a congenital SBO meant my pars fragment was somewhat atrophied, but it was "very solid", said Dr. Corenman in the operative report. Nevertheless, it was challenging with two things to fix, the pars and SBO, and OR time was around 4 hours. Recovery over the following months was guided by a very clear "Spine binder" from the Steadman Clinic with strict rules of "no BLT" (no bending, lifting or twisting), and illustrated physiotherapy guidelines. They even warned patients to avoid fish oil supplements, which could excessively dampen inflammation and hence slow bone healing. They answered many questions I had during months of recovery, with responses coming from the very supportive Lori Fugate (then director of Dr. Corenman's practice), and Ehrich Bean (then physician's assistant at the practice), as well as a couple calls with Dr. Corenman himself after two of the CT scans. Ehrich Bean offered great advice for taking the spine binder conservatively due to the nature of pars repairs vs. fusions. The final post-op CT scan I had was a couple weeks ago at 34 months post-op, and Dr. Corenman had retired, but I got a very positive and informative call from Eric Strauch (current PA at the Steadman Clinic under Dr. Corenman's replacement there, and who had also worked with Dr. Corenman previously). The staff at the Steadman Clinic were extremely supportive all the way through the process. I should mention, the local Canadian spine surgeon did offer me very good post-operative support including antibiotics as needed to deal with a mild surface incision-site infection early on, booking numerous x-rays when I felt something was amiss, as well as booking all four of my post-op CT scans. I am very grateful for that support also.

My final result shows plenty of solid bone across the pars and a healed SBO, with my vertebral body now a solid bone ring instead of being broken at two places as it was pre-op. Does my spine hold up in the real world? You bet! I have recently dug and moved several yards of dirt and sand and gravel by myself (shovel and wheelbarrow!) to fix our water main, pulled roots from the yard, moved several "portable" (these are HUGE) air conditioners up several flights of stairs my myself, and lifted weights. I now run 2 miles (3.2 KM) several times weekly with a hard 100 meter dash in the middle. I bend deeply before each run I go on, with no spine slippage. My spine feels amazing. I can bend over to do exercise, or real word tasks, with no risk of spine slippage.

My sincere thanks to God, Dr. Donald Corenman, Lori Fugate, Ehrich Bean, Eric Strauch, and the Steadman Clinic, as well as the Canadian spine surgeon who offered me excellent post-operative care back in Canada. You have all given me a new lease on life.

Sincerely,
Eric S

Robert S

May 11, 2021

by Robert S on Donald Corenman, MD, DC

Back Fusion Surgery

I had my entire lumbar spine fused in November of 2018. I had scoliosis , with pinched nerves that were so painful I could hardly walk - and standing for more than a few minutes was impossible. Even sitting was painful.
The fusion surgery produced immediate relief! And the recovery was much easier than I expected.
To this day I can do all the activities I love from hiking, to standing in a stream fly fishing to riding my bike long distances - or just walking down the street with my wife.
Kudos to Dr. Corenman and his staff, (including the two Erics) for taking such good care of me!

Leslie R

Jul 9, 2020

by Leslie R on Donald Corenman, MD, DC

TLIF

I had my TLIF surgery on 6/24/2020 by Dr. Corenman, I can not say enough good things about the Dr or his staff. I was always treated with respect and explained everything throughly, that made it easy for everyone to understand. I highly recommend Dr. Corenman and the Steadman Clinic.

Spinal Cord and Peripheral Nerve Stimulation