Letters to the Editor POSTRADIATION
DENTAL EXTRACTIONS WITHOUT HYPERBARIC OXYGEN
To the Editor In their recent paper, “Postradiation Dental Extractions Without Hyperbaric Oxygen” (ORAL SURG ORALMEDORALPATHOL,1991;72:270-4),Maxymiw et al. make a case for an atraumatic surgical technique with the use of nonlidocaine (Xylocaine) local anesthesia (preferably with low vasoconstrictor concentration) and the use of perioperative antibiotics to prevent the development of osteoradionecrosis(ORN) after extraction of teeth in a previously irradiated field. Apparently they report no incidence of ORN after extraction of teeth from areas both inside and outside the radiation field. They attribute these results to the above-mentioned factors. Although the significance of an atraumatic surgical technique is universally accepted, the contribution of the other two factors mentioned above is still questionable. In the third paragraph of their discussion, they state: “This study was undertaken to evaluate the incidence of ORN after radiotherapy for head and neck malignancies, with dental extractions performed in a specific manner.” Has this paper answered the questions the authors themselvesposed?Of course not. In their closing paragraph, they state what type of study would possibly answer these questions: “It is possible to instigate studies to analyze the influence of antibiotic coverageor local anesthetic in isolation, although studies with traumatic surgical techniques on human subjects [are] clearly unethical.” They continue, “A prospectively randomized trial evaluating the relative contribution of antibiotic coverage or choice of local anesthetic to the low incidence of ORN is possible,but both maneuversare so easily performed, with low risk and cost to patients, that the necessity of such a trial becomesquestionable”!!! In other words, “take our word, we know . . . ” Now they become both the judge and the jury at the same time. What if they do a prospective randomized trial and find no difference in the incidence of ORN in their
different groups? Then their radiation oncologists should get all the credit for a technique that greatly minimizes the incidence of ORN. If their overall incidence of ORN is indeed so low, irrespective of the factors related to the surgical technique, then Princess Margaret Hospital can show the way again and suggest a technique that practically eliminates the possibility of development of ORN. It should be noted that theseauthors have presented their “technique” in the local dental literature.’ In that paper, discussing another report,2 they state that it is difficult to evaluate favorable results when hyperbaric oxygen, antibiotics, and an atraumatic surgical technique were used at the same time, which means that only a randomized prospective study could evaluate the different factors separately. But now, by proclaiming such a study “questionable,” they do not even know themselves what is the reason for their low rate of ORN. As for their indictment of lidocaine as a potential contributing factor to the development of ORN, we believe it is still little more than a hypothesis, as it was before they undertook their study. They go through a list of studies, both in vitro and in vivo, that show a great deal of potentially detrimental effects that lidocaine has in connective tissue regeneration. Even if we can assumethat these results can be extrapolated to the human body, it is very difficult to admit that injection of this substancearound the mandibular ramus for inferior alveolar nerve block and lingual nerve block, or even local infiltration in the area for extraction of mandibular teeth, could precipitate ORN in a distant site in the mandibular body. Unless, of course, they feel that ORN starts from the ramus and eventually involves the tooth-bearing aspectsof the mandible. “Neurotoxicity” after a local anesthetic injection has variously been attributed to such things as combination of low pH plus bisulfite antioxidant (chloroprocaine), direct trauma of injection (probably with resultant extraneuronal or intraneuronal hematoma 155
156
ORAL SURG ORAL MED ORAL PATHOL August 1992
Letters to the editor
formation), the presence of preservatives from local anesthetic cartridge storage (especially alcohol), contaminants in the local anesthetic solution itself, excessiveconcentration of local anesthetic, and neuronal ischemia due to the vasoconstrictor, especially when used in the 1:50,000 solution. The tissue effects of intramuscularly administered lidocaine have been minor and reversible. Similarly, the lower “toxicity” of prilocaine, as cited in the article, refers to its systemic toxicity rather than local tissue toxicity and is explained on the basis of prilocaine’s lower protein binding (hence, larger volume of distribution), lower inherent vasodilatory activity, faster alpha, beta, and gamma phasesof distribution, hepatic clearance, metabolism, and excretion, and, finally, its capacity for considerable extra-hepatic storage and metabolism. Again, it is disappointing to seethe Princess Margaret Hospital, with its vast amount of material, not only miss the opportunity, but to consider “questionable” a randomized prospective study that could have been designedto give more insight into the pathogenesis of ORN. Nick Katsikeris,
DDS, Dr Dent
Assistant Professor of Oral and Maxillofacial Surgery Faculty of Dentistry, University of Toronto and Staff Oral Surgeon The Toronto Hospital
Earle R. Young, BSc, DDS, BScD, MSc, FADSA Assistant Professor and Acting Head, Department of Anaesthesia Faculty of Dentistry, University of Toronto and The Wellesley Hospital REFERENCES 1. Maxymiw WG, Wood RE. A case of severe post-radiation caries. Ontario Dentist 1990;67:32-6. 2. Kraut RA. Prophylactic hyperbaric oxygen to avoid osteoradionecrosis when extractions follow radiation therapy. Clin Prev Dent I985;7: 17-20.
To the Editor:
We welcome the opportunity to respond to the letter to the editor concerning our recent article on dental extractions without hyperbaric oxygen in irradiated patients (ORAL SURG ORAL MED ORAL PATHOL 1991;72:270-4.). We believe the letter needlessly obfuscates the intent and content of our paper. The honorable gentlemen state that Drs. Maxymiw, Liu, and Wood have made themselves the judge and jury
and are telling the reader, “Take our word, we know. . .” This is not the case. By undertaking this investigation and presenting its results, we are asking the reader to share in our experience with more than 70 patients. Since the time of the manuscript preparation we have treated approximately 35 more patients with identical results. To paraphrase the critics, we are only the witnesses,the reviewers are the judges, and the jury are those who read the article. We would also like to take this opportunity to note that head and neck patients at Princess Margaret Hospital do indeed developosteoradionecrosis(ORN) and that this is not a rare event. Most of the casesof ORN seenin our clinic arise from ill-fitting dentures, from surgical resection for salvage of radiated failures, as a spontaneousevent in a very few (where, we must note, extractions were not performed), and as a result of extractions done outside our clinic. Two interesting casesof ORN after extraction occurred recently. The first was in a patient who had hyperbaric oxygen at Dr. Katsikeris’ hospital and the secondwas a patient whose son, a dentist, performed extractions without antibiotic coverage but with a lidocaine-containing local anesthetic. The writers of the letter to the editor noted that “then Princess Margaret Hospital can show the way again and suggest a technique that practically eliminates the possibility of development of ORN.” The technique we delineate in the article did not “practically eliminate ORN ,” it did eliminate it. They also mention that our indictment of lidocaine is “little more than a hypothesis.” Looking at this in a broad scientific manner, we supposethat everything is a hypothesis but those very few immutable truths of the universe. Our study, however, does lend credence to the concept of avoiding lidocaine in this selected group of patients. In summary the two main thrusts of our paper were as follows: 1. In a sizable number of patients, teeth that were assumedto be within the radiated field were not when the isodose curves and check films were analyzed and, therefore, probably required no special treatment. The input of a radiation oncologist in this regard is invaluable. 2. In those patients whose teeth were extracted in the radiation field, no hyperbaric oxygen was delivered and no osteoradionecrosis resulted. It’s cheap. It’s safe. It works. We sincerely believe we have attained our two goals. We truly believe that although we have not pinned down the precise factor that is responsible for
DENTAL EXTRACTIONS WITHOUT HYPERBARIC OXYGEN
To the Editor In their recent paper, “Postradiation Dental Extractions Without Hyperbaric Oxygen” (ORAL SURG ORALMEDORALPATHOL,1991;72:270-4),Maxymiw et al. make a case for an atraumatic surgical technique with the use of nonlidocaine (Xylocaine) local anesthesia (preferably with low vasoconstrictor concentration) and the use of perioperative antibiotics to prevent the development of osteoradionecrosis(ORN) after extraction of teeth in a previously irradiated field. Apparently they report no incidence of ORN after extraction of teeth from areas both inside and outside the radiation field. They attribute these results to the above-mentioned factors. Although the significance of an atraumatic surgical technique is universally accepted, the contribution of the other two factors mentioned above is still questionable. In the third paragraph of their discussion, they state: “This study was undertaken to evaluate the incidence of ORN after radiotherapy for head and neck malignancies, with dental extractions performed in a specific manner.” Has this paper answered the questions the authors themselvesposed?Of course not. In their closing paragraph, they state what type of study would possibly answer these questions: “It is possible to instigate studies to analyze the influence of antibiotic coverageor local anesthetic in isolation, although studies with traumatic surgical techniques on human subjects [are] clearly unethical.” They continue, “A prospectively randomized trial evaluating the relative contribution of antibiotic coverage or choice of local anesthetic to the low incidence of ORN is possible,but both maneuversare so easily performed, with low risk and cost to patients, that the necessity of such a trial becomesquestionable”!!! In other words, “take our word, we know . . . ” Now they become both the judge and the jury at the same time. What if they do a prospective randomized trial and find no difference in the incidence of ORN in their
different groups? Then their radiation oncologists should get all the credit for a technique that greatly minimizes the incidence of ORN. If their overall incidence of ORN is indeed so low, irrespective of the factors related to the surgical technique, then Princess Margaret Hospital can show the way again and suggest a technique that practically eliminates the possibility of development of ORN. It should be noted that theseauthors have presented their “technique” in the local dental literature.’ In that paper, discussing another report,2 they state that it is difficult to evaluate favorable results when hyperbaric oxygen, antibiotics, and an atraumatic surgical technique were used at the same time, which means that only a randomized prospective study could evaluate the different factors separately. But now, by proclaiming such a study “questionable,” they do not even know themselves what is the reason for their low rate of ORN. As for their indictment of lidocaine as a potential contributing factor to the development of ORN, we believe it is still little more than a hypothesis, as it was before they undertook their study. They go through a list of studies, both in vitro and in vivo, that show a great deal of potentially detrimental effects that lidocaine has in connective tissue regeneration. Even if we can assumethat these results can be extrapolated to the human body, it is very difficult to admit that injection of this substancearound the mandibular ramus for inferior alveolar nerve block and lingual nerve block, or even local infiltration in the area for extraction of mandibular teeth, could precipitate ORN in a distant site in the mandibular body. Unless, of course, they feel that ORN starts from the ramus and eventually involves the tooth-bearing aspectsof the mandible. “Neurotoxicity” after a local anesthetic injection has variously been attributed to such things as combination of low pH plus bisulfite antioxidant (chloroprocaine), direct trauma of injection (probably with resultant extraneuronal or intraneuronal hematoma 155
156
ORAL SURG ORAL MED ORAL PATHOL August 1992
Letters to the editor
formation), the presence of preservatives from local anesthetic cartridge storage (especially alcohol), contaminants in the local anesthetic solution itself, excessiveconcentration of local anesthetic, and neuronal ischemia due to the vasoconstrictor, especially when used in the 1:50,000 solution. The tissue effects of intramuscularly administered lidocaine have been minor and reversible. Similarly, the lower “toxicity” of prilocaine, as cited in the article, refers to its systemic toxicity rather than local tissue toxicity and is explained on the basis of prilocaine’s lower protein binding (hence, larger volume of distribution), lower inherent vasodilatory activity, faster alpha, beta, and gamma phasesof distribution, hepatic clearance, metabolism, and excretion, and, finally, its capacity for considerable extra-hepatic storage and metabolism. Again, it is disappointing to seethe Princess Margaret Hospital, with its vast amount of material, not only miss the opportunity, but to consider “questionable” a randomized prospective study that could have been designedto give more insight into the pathogenesis of ORN. Nick Katsikeris,
DDS, Dr Dent
Assistant Professor of Oral and Maxillofacial Surgery Faculty of Dentistry, University of Toronto and Staff Oral Surgeon The Toronto Hospital
Earle R. Young, BSc, DDS, BScD, MSc, FADSA Assistant Professor and Acting Head, Department of Anaesthesia Faculty of Dentistry, University of Toronto and The Wellesley Hospital REFERENCES 1. Maxymiw WG, Wood RE. A case of severe post-radiation caries. Ontario Dentist 1990;67:32-6. 2. Kraut RA. Prophylactic hyperbaric oxygen to avoid osteoradionecrosis when extractions follow radiation therapy. Clin Prev Dent I985;7: 17-20.
To the Editor:
We welcome the opportunity to respond to the letter to the editor concerning our recent article on dental extractions without hyperbaric oxygen in irradiated patients (ORAL SURG ORAL MED ORAL PATHOL 1991;72:270-4.). We believe the letter needlessly obfuscates the intent and content of our paper. The honorable gentlemen state that Drs. Maxymiw, Liu, and Wood have made themselves the judge and jury
and are telling the reader, “Take our word, we know. . .” This is not the case. By undertaking this investigation and presenting its results, we are asking the reader to share in our experience with more than 70 patients. Since the time of the manuscript preparation we have treated approximately 35 more patients with identical results. To paraphrase the critics, we are only the witnesses,the reviewers are the judges, and the jury are those who read the article. We would also like to take this opportunity to note that head and neck patients at Princess Margaret Hospital do indeed developosteoradionecrosis(ORN) and that this is not a rare event. Most of the casesof ORN seenin our clinic arise from ill-fitting dentures, from surgical resection for salvage of radiated failures, as a spontaneousevent in a very few (where, we must note, extractions were not performed), and as a result of extractions done outside our clinic. Two interesting casesof ORN after extraction occurred recently. The first was in a patient who had hyperbaric oxygen at Dr. Katsikeris’ hospital and the secondwas a patient whose son, a dentist, performed extractions without antibiotic coverage but with a lidocaine-containing local anesthetic. The writers of the letter to the editor noted that “then Princess Margaret Hospital can show the way again and suggest a technique that practically eliminates the possibility of development of ORN.” The technique we delineate in the article did not “practically eliminate ORN ,” it did eliminate it. They also mention that our indictment of lidocaine is “little more than a hypothesis.” Looking at this in a broad scientific manner, we supposethat everything is a hypothesis but those very few immutable truths of the universe. Our study, however, does lend credence to the concept of avoiding lidocaine in this selected group of patients. In summary the two main thrusts of our paper were as follows: 1. In a sizable number of patients, teeth that were assumedto be within the radiated field were not when the isodose curves and check films were analyzed and, therefore, probably required no special treatment. The input of a radiation oncologist in this regard is invaluable. 2. In those patients whose teeth were extracted in the radiation field, no hyperbaric oxygen was delivered and no osteoradionecrosis resulted. It’s cheap. It’s safe. It works. We sincerely believe we have attained our two goals. We truly believe that although we have not pinned down the precise factor that is responsible for
