A Case Study: Nerve Injury Following Root Canal Procedure

The plaintiff, a 45-year-old married man, awoke one morning with severe pain in tooth #19. Because his regular dentist was unavailable that day, he obtained an appointment with his coworker’s general dentist. That dentist promptly referred him to the defendant, an endodontist, for a root canal. Because he did not have an appointment, he was accepted as an “add-on.” The patient arrived at 2:00 p.m. but was not seen for over two hours despite his severe pain. This delay might have been due to his being added to the schedule.

When the defendant did finally see the plaintiff, he injected the plaintiff with a standard mandibular block using carbocaine. The plaintiff stated that he immediately felt an “electrical jolt” or “bee sting” from the shot and claimed that he moaned and grabbed the chair. The left side of his face promptly went numb. The defendant began the initial root canal process and then gave the plaintiff an appointment four days later so he could complete the process.

After the anesthetic wore off, the plaintiff claimed that he was left in severe pain and left five messages for the defendant over the course of the evening but never received a return telephone call. The following day, he claimed he left further messages for the defendant at his office, again without a response. That evening, because the pain did not subside, he went to the Emergency Department of a local hospital for pain medication.

The following day, he did see the defendant and complained of numbness in his lower left lip and chin, as well as continuing severe pain. The defendant advised him that his face was swollen because he had an infection and proceeded to drain purulent material from the site. That same evening, the plaintiff again called the office complaining of severe pain. The dentist on call that night responded, prescribed antibiotics and increased the plaintiff’s pain medication dose.

Approximately two weeks later, the defendant completed the root canal procedure. Since the plaintiff continued complaining of numbness and paresthesia, the defendant checked his chin and lip at that visit and documented this problem. He allegedly advised the plaintiff that because the paresthesia was improving, it would diminish in time. The plaintiff later saw several physicians, including a neurologist, who advised him that the numbness and tingling of his lower lip might be permanent. They recommended he pursue lip therapy. Fortunately, the numbness of his chin had improved.

The Lawsuit

The plaintiff then commenced a lawsuit against the defendant, claiming that the defendant had injected the wrong spot with the anesthetic, injected the anesthetic too quickly after failing to appreciate the appropriate landmarks of the plaintiff’s mouth for injection and failed to immediately withdraw the needle as soon as the plaintiff reacted to the “electric jolt.”

The defendant denied all these allegations. He testified that the plaintiff was in severe pain before the block and did not react in an unusual manner. He stated he did note all landmarks before injecting the patient, as was his custom and practice, and that the injection occurred over a period of 30 seconds, which was also his usual practice. However, the defendant’s records were scanty. They did not discuss how he injected the plaintiff and contained minimal documentation about an informed consent discussion. The signed consent form did not mention numbness or paresthesia as a risk. Further, the record contained only one note of a telephone call, which was the documentation of the on-call dentist.

Although the plaintiff said the numbness was immediate, the first documentation of paresthesia was written two weeks after the plaintiff’s initial visit. The note refers only to that visit and not any prior visits. On the plaintiff’s last visit, the defendant told the plaintiff that the cause of the paresthesia was likely swelling from the infection in tooth #19 and that it would resolve. The plaintiff failed to keep his next two appointments, and the defendant never saw him again.

Eventually, tooth #19 was extracted by another dentist due to an infection in that tooth. The plaintiff never replaced the tooth with a bridge or implant, as recommended, because of his fear of further dental injury. The plaintiff claimed that he is now self-conscious about speaking because, due to the numbness, he drools and does not know when food is on his face. He also claimed he smiles less often because of the missing tooth.

Expert Reviews

Experts who reviewed this case for the dentist raised concerns about the fact that the written consent form the defendant used lacked any mention of the risk of paresthesia. The reviewers raised the possibility that the injury was due to inflammation from the root canal rather than the injection. They all noted that defending a paresthesia injury is difficult, even in the absence of a deviation from the standard of care. However, since the defendant was an experienced endodontist, they all felt the case was defensible.

Trial

The case went to trial before a jury. The plaintiff made a believable witness and did not try to embellish his injuries. He testified that he was the last patient of the day and that the defendant appeared rushed and agitated. This would be consistent with his two-hour wait at the office because he was an add-on patient, and the dentist was at the end of a busy day. The plaintiff also expressed anger that the defendant failed to return his numerous calls for the two days he experienced severe pain. However, he admitted that he did not pursue lip therapy to diminish or improve the paresthesia, as recommended by the two neurology experts he had seen.

The defendant was called as the next witness by the plaintiff’s counsel. He admitted under cross-examination that he failed to document the numbness when the plaintiff first complained of it. He testified that he did not recall the plaintiff flinching at the time of the injection, as the plaintiff was already in severe pain from the infection. He then testified that he gave the injection of the anesthetic over a period of 30 seconds, describing his customary procedure in depth. Notably, the defendant only came to court to give his testimony. He did not attend the remainder of the trial.

The plaintiff’s expert, a general dentist, not an endodontist, demonstrated to the jury how the injection should be given. He testified that the patient must be observed at all times and the needle is immediately withdrawn if the patient experiences an electrical shock sensation, as that means the nerve has been injected. He also claimed that the defendant gave the injection too quickly. He stated a patient should be injected over a period of 60 seconds, not 30 seconds. During cross-examination, he admitted to having testified multiple times as an expert witness for the plaintiff’s counsel.

The defendant produced two expert witnesses. The first, an oral and maxillofacial surgeon who had examined the plaintiff, confirmed that the plaintiff had decreased sensation on the left aspect of his lip midline to the left commissure but testified that the paresthesia was mild.

The second was an academic dentist who taught dental students how to inject patients. This expert quoted many studies that stated that an electrical sensation does not always correlate with a paresthesia injury. This expert further testified that the defendant did not depart from the standard of care when injecting the patient. However, on cross-examination, the expert conceded that many textbooks stated that 60 seconds was the appropriate length of time to inject a local anesthetic. All the experts for both the plaintiff and the defendant agreed that this type of injection of a local anesthetic is blind and that paresthesia can result from this injection in the absence of negligence.

Defense counsel argued in his summation that there was no deviation from the standard of care and that the plaintiff’s injury was not caused by the defendant but by the infection and subsequent swelling. After deliberation, the jury returned a six-figure verdict in favor of the plaintiff for past pain and suffering but gave him no money for future pain and suffering. MLMIC’s legal department and counsel for the defendant dentists determined that there were no issues for appeal.

Takeaways

The patient should be told the risks, benefits and alternatives to the proposed treatment and thus must be documented in the chart that the provider told the patient all of that. The risks discussed must include the most serious and frequent risks, but it does not mean there needs to be a long list. Then, the dentist must document that the patient was given the chance to ask questions and then consented to the procedure. The consent discussion can be written in shorthand indicating the risks, benefits and alternatives, including no treatment, were discussed and that the patient consented. Documentation of a consent discussion is critical so the patient cannot say that a consent discussion did not occur.

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This document is for general purposes only and should not be construed as medical or legal advice. This document is not comprehensive and does not cover all possible factual circumstances. Because the facts applicable to your situation may vary, or the laws applicable in your jurisdiction may differ, please contact your attorney or other professional advisors for any questions related to legal, medical or professional obligations, the applicable state or federal laws or other professional questions.