Reinnervation surgery

(updated 22 November 2022)

While any motor nerve can be cut and anastomosed (hooked up) to another nerve and over time this new nerve will grow into the muscles of the old nerve, the main reinnervation surgery that I perform for the voice, is to supply new neural input to the adductor muscles of the larynx. I typically use the omohyoid branch of the ansa cervicalis as the donor nerve and attach this to the anterior branch of the recurrent laryngeal nerve. This can provide new, additional and appropriate input to the muscle within the vocal cord (thyroarytenoid muscle or vocalis muscle). it can also supply the lateral cricoarytenoid muscle which is the muscle that closes the vocal cords together.

There are variations on this technique, including hooking a donor nerve up to the main branch of the recurrent laryngeal nerve. My colleague, Jean-Paul Marie, uses a branch of the phrenic as a donor nerve for the posterior cricoarytenoid muscles (ABductor) of the larynx. He offers a course in the surgery. 

Indications

There are two disorders which I typically use this surgery for. I use it for a paralyzed recurrent laryngeal nerve and I use it for a hyperkinetic or dyskinetic lateral cricoarytenoid muscle supplied by the anterior branch of the recurrent laryngeal nerve.

For an individual who has a paresis, that is, a partial paralysis, of the anterior branch of the recurrent laryngeal nerve, they can typically open the vocal cords but cannot close them all the way. This injury might occur after a viral illness or after a surgery in the neck stretches the nerve or possibly after an endotracheal tube compresses this branch of the nerve inside the larynx. While this type of injury often recovers spontaneously, in the case it where it does not recover, the individual has a choice between putting an implant in to statically move this weak vocal cord to the midline and restore the mass or choosing this type of surgery to re-innervate the weakened muscles. One reason an individual might choose this procedure is in hopes of having a more dynamic functioning vocal cord. While I think there are cases when this is true, there is not good scientific evidence that it is consistently true. There are many variables, including the surgeon's skill, the patient's age, in the judgment about when to do the surgery. The ansa cervicalis does send a signal when the person attempts to make sound and so it proves to be a reasonable nerve to restore innervation to a paretic vocal cord.

The second reason that I use this surgery is for individuals who have had a paralyzed vocal cord and the nerve has regrown. Sometimes this regrowth becomes leads to inappropriate timing and degree of contraction. I have seen instances, even 20 years after a nerve injury, where the injured vocal cord no longer moves appropriately. It often has been sitting still, but now begins to hyper contract when the person breathes in. I suspect this is from crossover of the injured nerve. Nerve fibers that originally went to the opening muscle of the voicebox (the posterior cricoarytenoid muscle), after the injury have now grown back to the opposing muscles, the adductor muscles. The effect of this is that when the individual breeze in, the paralyzed vocal cord moves towards the normal one and closes off the airway to varying degrees. Sometimes this occurs chronically. Other times this occurs intermittently as strong and sudden spasms, laryngospasms, which temporarily nearly completely shut off the airway.

The surgery is designed to restore bulk to the thyroarytenoid muscle and thus the vocal cord itself. To a lesser degree, it seems to restore some degree of active and appropriate closing (adduction) of the vocal cord. It is possible that it may restore some function and thus some improved pitch and volume control. An individual interested in singing might choose the surgery over the static implant (Medialisation laryngoplasty).

Presurgery

A good endoscopic examination to establish the need and potential benefit for this type of surgery is essential.

A PARQ conference is held with you. This is an acronym for Procedures, Alternatives, Risks and Questions. It means that your surgeon has discussed with you in full detail the reasons for going to surgery and that you are satisfied with those reasons.

Risks

The main risks of the procedure are anesthesia, a less-than-expected beneficial outcome, bleeding, infection, or a poorer-than-expected voice quality.

  • Anesthesia
    • The risk of anesthesia is that you could have a major life threatening reaction to some medication. This is very uncommon and I would compare it to getting in your car and driving some distance with the risk of an accident and dying. Even though the risk is severe, it is acceptably small, as most of us continue to drive. In the case of surgery, you even have the added benefit of life support equipment and trained personnel standing by. This procedure is performed under general anesthesia and the operation may last about 2 hours.
  • Less-than-expected beneficial outcome
    • If the nerve does not grow in, the individual may be left with a soft and weak voice.
  • Bleeding
    • Bleeding is a potential risk anytime a cut is made. This is primarily a problem after the surgery, where, if a blood vessel breaks, a hematoma may form under the skin that could require another surgical procedure to drain it out. If you are on any medication that may thin the blood, that would increase the risk. Examples of medications that might prolong bleeding include Coumadin, aspirin or even vitamin E. You should go over all medications that you take with your physician before surgery. A drain may be left in the wound for blood or fluid to come out. It would typically be removed in one to three days.
  • Infection
    • Any time a skin incision is made, that becomes a route for bacteria to enter into the body. This procedure is performed under sterile conditions and an antibiotic may be given in the operating room.

Surgery

Anesthesia

General anesthesia is utilized with an endotracheal tube down your throat to breathe for you while asleep. The procedure lasts about three to five hours.

Preanesthesia room

In the preanesthesia area, you get to wear that famous "open back" gown. You will be there for about an hour answering many questions for the tenth or perhaps the twentieth time. You learn that you actually lead a very interesting life judging from the thickness of the stack of papers representing you in the medical record. You may be given a sedative, depending on your wishes and your anesthesiologists recommendations. From the preanesthesia room, you leave your family and ride on your back, staring at the ceiling, to the operating room.

The operating room

The operating room table is often pre-chilled (I warned you). The surgery is done with you in a lying down position.

The procedure

After you are asleep, your neck is prepped to be made sterile. Usually a solution of iodine is used unless you are allergic to iodine. Drapes are placed to keep the neck area sterile.

About a two to three inch incision is placed in your neck over the voice box. It is placed in or parallel to a skin crease to aid in hiding it later on. A nerve called the Ansa Cervicalis is located on each side of the neck. It is located adjacent to the sternocleidomastoid muscle and the omohyoid muscle. Later in the case, this nerve is cut and routed into the voicebox. The assumption is that this nerve is not affected by the spasms that the nerve to the voice box is.

Several layers of muscles are pulled aside and the thyroid cartilage is exposed. The thyroid cartilage is the front of the voice box, and in men it is often known as the Adam’s apple. Some of the muscles attached to the voice box (thyrohoid) are disconnected. The cricothyroid muscle may also be disconnected - as this is the muscle that creates our upper voice; disconnecting this would account for the loss of the higher pitches. A window is created into the voice box and two of the muscles that ADduct or close the vocal folds are visualized. Typically, the branch of the nerve supplying these muscles (anterior branch of the recurrent laryngeal nerve) is visible on their surface. If it is difficult to distinguish the nerve from other tissue, the recurrent laryngeal nerve is stimulated with an electrical pulse and an EMG monitor placed into or on the vocal cord muscles will activate when the nerve branch is found.

The anterior branch is cut. The ansa cervicalis nerve is now cut and then sutured to the anterior branch which goes to the thyroarytenoid muscle.

Recovery

You wake up typically in the recovery room. You stay in the recovery room until the nurses and anesthesiologist are certain the majority of the anesthetic is gone from your system. You will then return to your room.

Pain

There may be moderate pain after surgery. Since pain varies from person to person, I would typically prescribe Vicodin. Vicodin is essentially Tylenol and a narcotic, hydrocodone. For some, hydrocodone produces less nausea than codeine. This may be used for either throat pain or for a throat tickle or cough. There are extensive options for management of pain.

Instructions during healing

  • First week(s)
    • It is likely that you will have a vey weak voice. It is also likely that you will have initial difficulty swallowing liquids without choking on them. Drinking through a straw or with your head tucked to your chin may help alleviate some of the choking. Thickening of drinking liquids may also help.
      The incision should be kept dry for at least 24 hours after surgery. This allows enough time for the skin edges to seal over.  I typically place cyanoacrylate glue over the incision which allows it to get wet fairly early after the surgery.
      Speaking will also be a bit of work. When the vocal cords don’t occlude tightly (and they won’t after surgery for a while) it takes a lot of air to set them vibrating. This leads to several symptoms. Most people say they are “short of breath”. You will actually be running a lot of air in and out of the lungs. You may feel dizzy or lightheaded from what amounts to hyperventilation. Talking and walking at the same time could be difficult. Additionally, the voice as it recovers may sound a bit high or squeaky. The muscles that create high pitch (cricothyroid) try to kick in and bring the weakened vocal cords together.
      Scars go through a maturation process that takes about a year. During the first half of that time, the scar will tend to be pink and will tend to pigment very easily if exposed to the sun. That will make the scar more visible. I recommend using SPF 40 sunscreen to prevent this pigmentation. I have no opinion on the use of vitamin E on the incision. It certainly does no harm, though I do not know that it helps. Since the voice box elevates when swallowing, the scar can tether to the deeper tissues and move conspicuosly during swallowing. This may correct with time or be corrected later after healing finishes.
  • Six weeks
    • Return for a follow up visit to see how you have healed. Feel free to use your voice as much as you can tolerate.
  • Three months
    • Mid-term evaluation, if possible
  • Six months
    • If you are in the area, I would like to see you
  • One year
    • Long-term evaluation of your surgery.