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Lingual Nerve Injury from Anesthetic Injections

This topic is my main motivation for building this web site.  Having been in pain from a lingual nerve damage for about 24 months now, I have explored all the aspects of this injury, as well as the available therapies (see treatment page).  This is my first attempt to write down what I have elucidated, and I hope to refine this page on the second or third pass, including adding a bibliography.  If you have lingual nerve damage from a dental anesthetic injection resulting in numbness or a painful neuropathy, I hope you find this information useful.  Nerve damage from an inferior alveolar nerve block is a rare complication, so you may be the only visitor this year, or maybe at all.  I would welcome hearing from any and all that visit this site, with any comments or suggestions welcome.

Damage to the lingual nerve results in pain within the tongue and along the mucosa on tongue side of the teeth (inner buccal mucosa).  The pain can be burning, dull, achy or a combination.  You may also have numbness as the only symptom, or can have a combination of numbness and pain.  

First, if you have recently suffered an injectional lingual nerve damage, please find an experienced oral surgeon and nerve pain clinic, and let them help you decide how you want to proceed.  There is not an established treatment protocol.  Most (at least 85%) of these injuries resolve on their own, so most dentists just try to calm your fears and tell you that everything will be fine.  They will be right at least 85% of the time.  Most dentists do not know much else about this injury, and may not be able to provide any additional help.  Those physicians and dentists that are members of The American Academy of Orofacial Pain have an interest in this area, and if they do not treat these types of conditions themselves, they may be able to refer to someone who does.

I have found that many physicians who deal with nerve injuries recommend a course of steroid therapy if the injury is recent.  A majority of ear nose and throat physicians, and one oral surgeon (with special expertise in lingual nerve damage) would have recommended a short course of oral steroids in my case had I consulted them just after the injury.  I have not been able to locate much literature on this topic, and one would want to weigh the risks of taking a short course of steroids (which is quite small), against the benefit that steroids might give to prevent nerve scaring (which is unknown).

How did this happen?  Well, basically someone blinding was sticking a needle into an area with major nerve trunks running through it and hoping to deposit a local anesthetic (typically lidocaine) around the area, but in your case the needle hit the nerve and it is possible that the injection was actually into the nerve.  The best web site I have found that demonstrates the technique (but requires that Quicktime be installed - available for free at http://www.apple.com as well as a java capable browser) is: http://gracilis.usask.ca/dents/mandibs.htm .

The anatomy can be seen in the following anatomic drawings of the area.  Notice the proximity of the lingual nerve to the inferior alveolar nerve.  The purpose of the anesthesia is to numb the inferior alveolar nerve, and the lingual nerve is just an innocent bystander.  

Figure 1       Figure 2         Figure 3

The mechanism of injury is not known for sure.  It includes trauma from the needle itself.  There is one source that notes that during the procedure, the needle tip may contact bone and become bent.  If this needle had pierced the lingual nerve on the way through, it may cause significant physical trauma as it is withdrawn.  Many suspect that the injury is due to an intraneural injection of the local anesthetic, that is, an injection directly into the nerve itself.  While the local anesthetic deposited just outside the nerve is relatively harmless, it may be neurotoxic if injected directly into the substance of the nerve itself.  It may disrupt the nerve fibers and cause intraneural fibrosis

How frequently does this occur?  The numbers are some what up to speculation.  Some of the experts think that this injury is under reported.  The number of people with this injury within the United States is unknown.  I visited with one expert that follows 76 patients at this time, with this injury.  Some have numbness, some have pain.  He thinks he has spoken to over 500 by phone.  

Looking to the literature, one study found that the lingual nerve was damaged 0.15% of the time, but that after 6 months, only 0.008% were still injured (8 in 100,000).   Another study found that approximately 1 in 800,000 suffered lingual nerve damage due to injection that resulted in persistent pain.  A more recent study finds that the incidence is between 1 in 26,000 and 1 in 160,000.  While this is a rare injury, given the number of injections occurring within the United States daily, there may be a significant number of injured people as a result. 

How do I avoid this injury?  See the alternatives section.  Although many people have low thresholds of pain and feel that they need some help in order to undergo dental procedures, many others have high thresholds and can undergo extensive dental work without much difficulty.  You need to know what your needs are, and find a dentist that understands and can meet your needs.

If you feel you must have a nerve block, have it done with a 25 gauge needle, and setup hand signals with the dentist so that if you feel the needle hit one of the nerves ( which you can tell by the "shock" sensation), the dentist (or other operator), can withdraw and redirect the needle so as to try to avoid the injury.  This technique is described in one of the textbooks on dental anesthesia.  

What about treatment?  Well, unlike nerve injuries due to trauma or tooth removal, surgery is not a proven effective therapy at this point.  The injury is rare, so there are no prospective studies which compare therapeutic approaches, as far as I know.  If you have persistent pain, please see the treatment page for more information.

BEST ARTICLE ON THIS TYPE OF INJURY:

Permanent nerve involvement resulting from inferior alveolar nerve blocks.

 

11/07/01