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Dead People's Nerves Help Living

Dead People's Nerves Help Living

CREATED May 9, 2013

DALLAS (Ivanhoe Newswire) - When a nerve is injured, pain, numbness, and loss of sensation are common. Fixing damaged nerves used to mean patients had to sacrifice another nerve from their body, but now there's an easier way.

Jesse Head doesn't take the little things, like stealing a kiss from his girl, for granted since doctors found a large benign tumor in his jaw.

"It was just a general visit to the dentist and he found it on an X-ray," Jesse Head told Ivanhoe.

The tumor needed to be removed, but surgeons would also have to cut out Jesse's teeth, some of his jaw, and part of a large nerve.

"I'm dealing with nerves that involve sensation," John R. Zuniga, DMD, MS, PhD, Robert V. Walker DDS Chief in Oral and Maxillofacial Surgery, and Professor of Surgery at UT Southwestern Medical Center in Dallas, told Ivanhoe.

Dr. John Zuniga says taking a graft from the leg used to be the only way to repair a damaged nerve, but it leads to permanent numbness in the leg.

"It's a nerve injury to fix a nerve injury," Dr. Zuniga said.

Instead, the doctor used part of a cadaver on Jesse. AVANCE is an engineered nerve from a deceased donor. It's placed between the damaged segments and nerves regenerate through tiny tubes.

"It's a scaffolding. It's like a biologic scaffolding," Dr. Zuniga explained.

It helped Jesse keep the sensation in his face and mouth. Today, he's almost back to normal and he has a big event to look forward to!

"We are getting married," Jesse's fiancé told Ivanhoe.

Dr. Zuniga said he's seeing similar results with the FDA approved cadaver nerve as he sees when using a patient's own nerve. He said the most common causes of facial nerve damage include wisdom teeth extractions, jaw reconstructive surgery, dental implants, and needle injection injuries.

RESEARCH SUMMARY

BACKGROUND:   There are three types of nerves in the body, autonomic nerves, motor nerves, and sensory nerves.  Autonomic nerves control the involuntary activities of the body, including blood pressure, heart rate, and digestion.  Motor nerves control actions and movements by transferring information from the brain and spinal cord to the muscles.  Sensory nerves relay information from the skin and muscles back to the spinal cord and brain.  The information is then processed to let you feel pain and other sensations.  There are more than 100 different types of nerve damage.  (Source:  www.webmd.com)

SYMPTOMS:  Nerve damage can cause a wide range of symptoms.  Symptoms will depend on the location and type of nerves that are affected.  Damage could occur to nerves in the spinal cord and brain.  It can also occur in peripheral nerves, which are located throughout the rest of the body.

  • Autonomic nerve damage can cause sexual dysfunction, dry eyes and mouth, bladder dysfunction, constipation, too much sweating or too little sweating, lightheadedness, and inability to sense chest pain.
  • Damage to motor nerves can cause muscle atrophy, twitching, paralysis, and weakness.
  • Sensory nerve damage can cause sensitivity, pain, numbness, prickling or tingling, burning, and problems with positional awareness.  (Source: www.webmd.com)

TREATMENT:  In many cases, nerve damage cannot be cured.  Usually the first goal of treatment is to address the underlying condition that is causing the nerve damage.  This could mean: medications to treat autoimmune conditions, physical therapy or surgery to address compression or trauma to nerves, correcting nutritional deficiencies, regulating blood sugar levels for people with diabetes, or changing medications when drugs are causing the nerve damage.  Medications can also be aimed at minimizing the nerve pain.  (Source:www.webmd.com

NEW TECHNOLOGY:  Traditional methods of facial nerve reconstruction include autologous and cadaveric grafting; both can lead to patient morbidity.  Autologous nerve grafts are the "gold standard" for superior regenerative capability, but are limited by the length and potential.  Allogenic grafts from donors or cadavers have shown efficiency, but can require immunosuppression.  (Source:  http://www.ncbi.nlm.nih.gov/pubmed/21225804)  AVANCE Nerve Graft is peripheral nerve allograft for the reconstruction of peripheral nerve discontinuities (severed nerve gaps) in order to guide and structurally support axonal regeneration across a nerve gap caused by traumatic injury or surgical intervention.  It is a sterile extracellular matrix that is processed from human peripheral nerve tissue.  The AVANCE Nerve Graft was developed by AxoGen by following the princlipe that the human body created the optimal nerve structure.  The AVANCE Nerve Graft provides natural nerve structure of an autograft and the ease and availability of off-the-shelf products.  AVANCE Nerve Graft is made up of bundles of small diameter tubes that are held together by an outer tube.   It has been processed to remove noncellular and cellular factors like fat, cells, blood, axonal debris, and chondroitin sulfate proteoglycans while also preserving the three dimensional scaffold and structure of the peripheral nerve.  It is offered in a variety of sizes with lengths between 15mm and 70mm and diameters up to 5mm, allowing the surgeon to choose the correct length for the relevant nerve gap.  (Source:http://www.axogeninc.com/nerveGraft.html

INTERVIEW

John R. Zuniga, DMD, MS, PhD, Robert V. Walker DDS Chair in Oral and Maxillofacial Surgeon, and Professor in the Department of Surgery at the University of Texas Southwestern Medical Center in Dallas, talks about a new way to repair nerves.

So, before these new grafts, what would you do for a patient like Jesse? 

Dr. Zuniga: I would have to take what we call an autograft. With the amount of surgery in the reconstruction for Jesse, I would have had make several incisions on the inner side, the outside, and the backside of the leg from the ankle all the way into the midcalf to harvest a 7 to 10 cm nerve graft. As a result, Jesse would have permanent numbness on the side of his ankle and lateral foot on the side of the graft harvest.

So you are giving up one for another? 

Dr. Zuniga: That is correct. We are fixing one nerve by sacrificing another, but that was prior to AVANCE. That was the only viable solution we had for these patients. 

What is AVANCE? 

Dr. Zuniga: AVANCE is a specially prepared acellular nerve material. It is a cadaveric nerve that was advanced in the laboratory and taken to clinical trials and was FDA approved in the mid-2000's.

Is it nerves from cadavers?

Dr. Zuniga: That is correct.

How does it work?

Dr. Zuniga: It is acellular, meaning that a patented process is used to remove the cells in the cadaver nerve to avoid the problem of leaving cells in the transplant that can induce an immunologic reaction when implanted.

Does the body reject it like a transplant?

Dr. Zuniga: Exactly. Prior to AVANCE, there were only cellular components that were able to be transplanted. We could not use cadaveric nerve because in the traditional sterilization process the construct of the nerve would be destroyed. With AVANCE the immunologic components of the cells are removed, but the tubular construct in the cadaver nerve is preserved. There are thousands of these tubes and when we transfer the AVANCE nerve graft, and the patient's own nerve will regenerate through these tubes. So, AVANCE grafts retains the construct or structure of the nerve for nerve regeneration and removes the cellular component to eliminate the graft rejection components.

So, in one nerve there are thousands of tubes?

Dr. Zuniga: Correct.

Is that what becomes kind of like a scaffolding? 

Dr. Zuniga: Exactly. It is scaffolding. It is biologic scaffolding. 

When you were doing this before, was there a high risk of rejection because it was coming from your own body?

Dr. Zuniga: If it was autografted, there was no rejection possibility. However, it is a nerve injury to fix a nerve injury.  

With the cadaver nerves, is there any risk of rejection at all?

Dr. Zuniga: In my experience there has been no risk of graft rejection using AVANCE grafts.

How many of these have you done? 

Dr. Zuniga: I think we are on our number 20.

How is it going so far? 

Dr. Zuniga: It's been good so far. I am interested in the efficiency and the safety of it. We are yet to publish this data, but in our first experience of the first 20 we have measured efficiency, meaning that it works in regenerating sensation or feeling. In this case, I am interested in regenerating feeling to parts of the face as a result of loss of the original nerve by trauma, tumors, infections, fractures, things of that sort. I have not had any infections or graft rejections. I have not had any development of the very painful nerve problems afterwards and we have been very careful about monitoring that. So, in the 20 patients having grafts for more than one year, we have noticed that they are regaining some sensation. Again, that is what we are trying to do and it is safe in that there have been no infections, no rejections, and no development of pain problem afterwards.

Compared to the surgery that you take out of your own leg and this surgery, is the feeling basically the same that you are going to get back or not?

Dr. Zuniga: That is a good question and that is a question of efficacy. In other words, is the AVANCE or allograft better than the autograft? I do not know of anyone in my particular area that has been able to demonstrate that because that is going to take quite a few experiences. I cannot answer that right now. It is my feeling that I am seeing about the same types of results. It is not any better, but it is not any worse. So, to me the advantage is the elimination of the need to "take" a nerve to "fix" a nerve injury.

Of your 20 surgeries, what have you been able to repair; like Jesse and his jaw? Are they all similar to that? 

Dr. Zuniga: Well, my particular area of interest is in oral maxillofacial surgery. So, I am dealing with nerves that involve sensation, and some include the special sense of taste. There are 3 particular nerves that I repair. That is the nerve to the lip and chin, just like in Jesse's case. I can also repair the nerve to the tongue, which is also subject to injury and involves feeling and taste. Also, I can repair the nerve to the midface.

This would also give back someone's sense of taste?

Dr. Zuniga: Yes. We have recorded some return of taste in the lingual nerve injury patients.

Jesse had a tumor, but what are the other kinds of accidents that cause this kind of nerve damage?

Dr. Zuniga: At the top of the list is wisdom tooth extraction. Unfortunately, 1% of wisdom teeth extractions may result in some transient numbness involving the nerve to the tongue or to the lip or chin. Of that 1%, 75% recover spontaneously, but 25% do not because the injury is severe. It is a small number of patients, but we have an option for those people who have a lifelong facing having a numb tongue, loss of taste, or numbness of the lip and chin. We can offer them this intervention. The other most common cause is jaw reconstructive surgery. The third is implants now that dentists are using, tooth-formed metal implants. If they are placed too deep or inappropriately, they could injure these nerves. The fourth is needle injection injuries from the local anesthetics used by dentists.

Can you explain what happened to Jesse?

Dr. Zuniga: A stereolithographic is the model we used and it's a pretty good replication of Jesse's situation before his surgery. The beauty of this model is that it is see-through and the teeth are artificially white. They show the roots and all the crown forms. The inferior alveolar nerve enters the jaw in the back by the throat and then comes out a little hole and then goes into the lip and chin. That is why when the dentist numbs you up, the needle goes in the back of the throat, but you get numbness of your lip and chin. The same thing occurs if you injure the nerve in your jaw. Jesse's tumor was a benign tumor, not a malignant tumor. However, it was expanding and it was a destructive tumor. The beauty of this model is that you can twist it around, look underneath, and see the expansion. So, the lesion occupied at least three-quarters of his lower left jaw. So, in his treatment, we knew beforehand that in order to resolve this lesion we had to resect the jaw and the teeth. We also knew we could retain part of his jaw. A team of surgeons here at UT Southwestern performed the surgery on Jesse a little over a year ago. Our team resected his jaw and we spared the nerve as it came out of the bone and as it went into the bone. We removed part of his jaw and then we used AVANCE as a graft, which was 7 cm, to hook up the two ends of the intentionally cut nerve.

Is that a large graft?

Dr. Zuniga: It is a large graft.

How long is recovery?

Dr. Zuniga: The average hospitalization is probably around 5 to 7 days.

Can he move his jaw?

Dr. Zuniga: No. We actually wire his teeth together because that allows us to reestablish his bite and reestablish his form during and right after surgery

So, you take out the tumor and then it would 8 months before you could do the rest of it. He would go without feeling and he would not be all put together, but he said he had the tumor removed, his graft put in, and his new jaw in all in the same surgery?

Dr. Zuniga: Yes. We can do that with a benign tumor and that is the advantage of having more high technical materials, instruments and skills. Surgeons with experience and the materials that we have will have more predictable long-term and better outcomes for patients.

How long did that take to do the surgery?

Dr. Zuniga: I believe it was a full day. It was probably 6 to 8 hours.

So, when can he start using his jaw?

Dr. Zuniga: Well, the bone will have matured and fused within about 4 to 6 weeks.

Do you take the cadaver nerve out of the leg too?

Dr. Zuniga: No, the cadaver nerve is supplied.

FOR MORE INFORMATION, PLEASE CONTACT:

John R. Zuniga DMD, MS, PhD
Robert V. Walker DDS Chair in Oral and Maxillofacial Surgery
Professor in the Department of Surgery
University of Texas Southwestern Medical Center in Dallas
 (214) 648-3527
john.zuniga@utsouthwestern.edu