About the Difficulties of Local Anesthesia for Prevention of Trigeminocardiac Reflex Occurring under General Anesthesia

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LETTERS TO THE EDITOR

received the standard protocol of chemotherapy. Those with multiple myeloma also received steroids for short durations as part of the vincristine, Adriamycin, and dexamethasone protocol. Only 2 of the patients with multiple myeloma were receiving prolonged steroid therapy as part of the thalidomide protocol. None of our study patients received sunitinib,1 bevacizumab,2-4 or denosumab,5 the antiangiogenic/antiosteoclastic agents that were recently reported to cause osteonecrosis of the jaws. Moreover, no patients under oral BPs received prolonged steroid therapy. This low occurrence of steroid use among the patients under frequent IV BPs (12.5%) probably does not imply any correlation to the development of BRONJ in our group of patients. Only 2 patients were smokers: one was receiving an oral BP for the treatment of osteoporosis, and the other was receiving frequent IV BPs for the treatment of multiple myeloma. Type II diabetes mellitus was diagnosed in 3 patients, 2 of whom were receiving oral BP treatment for osteoporosis and 1 of whom was receiving frequent IV BP treatment for prostate carcinoma. We have diagnosed and treated more than 180 patients with BRONJ over the past few years. The rates of type II diabetes mellitus among patients under oral BPs (17%) and those under frequent IV BPs (15.5%) are close to its occurrence in the general population in this age group.6,7 Therefore, in our experience, type II diabetes mellitus does not appear to be a predisposing factor for either the development or the progression of BRONJ. TOWY SOREL LAZAROVICI, DMD NOAM YAROM, DMD Tel Hashomer, Israel

escaped the attention of the authors. The authors classified potential risk factors for trigeminocardiac reflex (TCR) and recommended prophylactic administration of a vagolytic drug (atropine) right before any surgical manipulation known to be risky for TCR. However, a simpler alternative to avoid this rare intraoperative complication would be to ensure that the surgical site is blocked with suitable regional nerve blocks using vasoconstrictors. This is routinely done during maxillofacial surgical procedures to ensure minimal bleeding and decrease postoperative pain. More importantly, local anesthesia blocks possible afferent pathways and prevents the reflex from occurring.2 I have personally never experienced TCR during maxillofacial surgical procedures, probably due to this reason. This is an easier alternative to prophylactic administration of vagolytic agents. A recorded instance of this complication during removal of a mesiodens was explained by possible inadequacy of local anesthesia in an already high-risk patient.3 Moreover, oral and maxillofacial surgical procedures usually require the preoperative administration of antisialagogues. Glycopyrrolate is more commonly used in our institution and this has a certain degree of vagolytic activity, albeit lower than that of atropine. Occurrence of TCR despite these precautions will require intravenous atropine as recommended by the authors. “To be forewarned is to be forearmed” is the conclusion of the article. “Prevention is better than cure” may be the more appropriate mantra. BALASUBRAMANIAN KRISHNAN, MDS, DNB, MOMSRCPS (GLASG) Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) Pondicherry, India

References

References

1. Brunello A, Saia G, Bedogni A, et al: Worsening of osteonecrosis of the jaw during treatment with sunitinib in a patient with metastatic renal cell carcinoma. Bone 44:173, 2009 2. Guarneri V, Miles D, Robert N, et al: Bevacizumab and osteonecrosis of the jaw: Incidence and association with bisphosphonate therapy in three large prospective trials in advanced breast cancer. Breast Cancer Res Treat, 122:181, 2010 3. Serra E, Paolantonio M, Spoto G, et al: Bevacizumab-related osteonecrosis of the jaw. Int J Immunopathol Pharmacol 22: 1121, 2009 4. Greuter S, Schmid F, Ruhstaller T, et al: Bevacizumab-associated osteonecrosis of the jaw. Ann Oncol 19:2091, 2008 5. Aghaloo TL, Felsenfeld AL, Tetradis S: Osteonecrosis of the jaw in a patient on denosumab. J Oral Maxillofac Surg 68:959, 2010 6. Varas-Lorenzo C, Rueda de Castro AM, Maguire A, et al: Prevalence of glucose metabolism abnormalities and cardiovascular co-morbidity in the US elderly adult population. Pharmacoepidemiol Drug Saf 15:317, 2006 7. Forouhi NG, Merrick D, Goyder E, et al: Diabetes prevalence in England, 2001— estimates from an epidemiological model. Diabet Med 23:189, 2006

1. Lübbers HT, Zweifel D, Grätz KW, Kruse A: Classification of potential risk factors for trigeminocardiac reflex in craniomaxillofacial surgery. J Oral Maxillofac Surg 68:1317, 2010 2. Bohluli B, Ashtiani AK, Khayampoor A, et al: Trigeminocardiac reflex: A MaxFax literature review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 108:184, 2009 3. Webb MD, Unkel JH: Anesthetic management of trigeminocardiac reflex during mesiodens removal–a case report. Anesth Prog 54:7, 2007

doi:10.1016/j.joms.2010.06.191

RE: CLASSIFICATION OF POTENTIAL RISK FACTORS FOR TRIGEMINOCARDIAC REFLEX IN CRANIOMAXILLOFACIAL SURGERY To the Editor:—I recently read the article “Classification of potential risk factors for trigeminocardiac reflex in craniomaxillofacial surgery”1 published in this journal. I would like to note a small yet pertinent point that seems to have

doi:10.1016/j.joms.2010.10.049

ABOUT THE DIFFICULTIES OF LOCAL ANESTHESIA FOR PREVENTION OF TRIGEMINOCARDIAC REFLEX OCCURRING UNDER GENERAL ANESTHESIA To the Editor:—We thank Dr Krishnan for his contribution.1 We agree that local anesthesia can inhibit the occurrence of the trigeminocardiac reflex (TCR) and that it should be a basic part of any maxillofacial procedure, even under general anesthesia. It is perhaps because local anesthesia is such a basic measure that we failed to mention it explicitly. However, we do not agree that this has any impact on the classification and its conclusions as proposed in the article.2 First, we do not recommend prophylactic administration of vagolytic drugs before any manipulation known to be risky, but only before “high-risk procedures” according to our classification.2 For craniomaxillofacial surgery, this would include “orbital exenteration” and “fractures in children with cardiac disease.” Both procedures are those in which

LETTERS TO THE EDITOR it is not possible to achieve complete local anesthesia blocks. Second, local anesthesia is known to fail or be incomplete in some cases, which Krishan himself discusses when he cites a case of TCR due to possible inadequacy of local anesthesia described by Webb and Unkel.3 Especially under general anesthesia, there is no way to ensure whether an anesthetic block is complete. Third, there are procedures that carry the risk of TCR but in which we prefer not to use local anesthetics, with or without vasoconstrictors, such as facial trauma with possible damage to blood vessels or the facial nerve. We want to find all sources of bleeding and be able to trigger artificially facial nerve branches. Both are avoided by vasoconstrictors and local anesthetics, respectively. In addition, although in parts methodically unclear and from the physiologic pathway hypothetic, there is some evidence for TCR occurring under complete local anesthetic block.4,5 We certainly agree that sufficient local anesthesia and general anesthesia might prevent some TCR events in maxillofacial surgery, but unfortunately this strategy is not applicable to many situations in craniomaxillofacial surgery. However, whenever suitable, we would also administer local anesthetics—preferably with vasoconstrictors—for the aforementioned reasons and would therefore concur with our colleague Dr Krishnan. HEINZ-THEO LÜBBERS, MD, DMD DANIEL ZWEIFEL, MD, DMD KLAUS W. GRÄTZ, MD, DMD ASTRID KRUSE, MD, DMD Clinic for Cranio-Maxillofacial and Oral Surgery University Hospital Zurich Zurich, Switzerland

References 1. Krishnan B: RE: Classification of potential risk factors for trigeminocardiac reflex in craniomaxillofacial surgery. J Oral Maxillofac Surg 69:962, 2011 2. Lubbers HT, Zweifel D, Gratz KW, Kruse A: Classification of potential risk factors for trigeminocardiac reflex in craniomaxillofacial surgery. J Oral Maxillofac Surg 68:1317, 2010 3. Webb MD, Unkel JH: Anesthetic management of the trigeminocardiac reflex during mesiodens removal–a case report. Anesth Prog 54:7, 2007 4. Lubbers HT, Zweifel D, Gratz KW, Kruse A: In reply (to trigeminocardiac reflex: Potential risk factor for syncope in exodontia?). J Oral Maxillofac Surg 68:2921, 2010 5. Arakeri G, Brennan PA: Trigeminocardiac reflex: Potential risk factor for syncope in exodontia? J Oral Maxillofac Surg 68:2921, 2010

doi:10.1016/j.joms.2010.10.048

COMMENTS ON “IMPROVING ESTHETIC RESULTS IN BENIGN PAROTID SURGERY: STATISTICAL EVALUATION OF FACELIFT APPROACH, STERNOCLEIDOMASTOID FLAP, AND SUPERFICIAL MUSCULOAPONEUROTIC SYSTEM FLAP APPLICATION” To the Editor:—We read the report by Bianchi et al1 with great interest. Their aim was to compare the outcomes of partial parotidectomy using a Blair incision without reconstruction and using a facelift incision with or without reconstruction. Although the study question is interesting, we have some discussion that can be listed as follows.

961 First, it is a common misunderstanding that the P ⬍ .05 is considered statistically significant, and P ⬍ .01 is highly statistically significant. In fact, the P value does not and cannot show the magnitude. Instead, it is only either significant or not. A P value of .001 does not reflect a larger effect than a P value of .04. Any small difference will be statistically significant (P ⬍ .05) if the sample size is large enough, regardless of the clinical relevance. If one would like to understand the quality of the estimated value, it is necessary to consider the confidence interval (CI). The width of the CI indicates the size and direction of the effect, the amount of random error, and the precision of the estimate. At present, many journals prefer statistical analyses based on the CI, instead of the P value. For details, please refer to our recent publication.2 Second, the authors did not describe how they selected the type of surgical procedures for each patient. We were surprised that within 1 decade, their patients were allocated to 4 different surgical techniques whose long-term outcomes were unknown to the authors themselves, yet the patient sample seemed to be homogenous (eg, clinical findings, tumor type, location, and extension). Was this operator dependent, or was any factor used to select the type of the surgery? This point is important and needs clarification. Third, the Helsinki Declaration requires “human subject protection” in every human research study. Research involving humans must not be mixed with routine practice and then later reported as a retrospective study.3 When the outcomes of the 4 treatments were unknown, especially at the beginning of the study period, was this study really exempted from formal ethical review at their institution? Is it possible that their study was a prospective study that was reported as a retrospective one (so that retrospective ethical review was unfeasible)? Were the patients informed that they would be the research sample and allocated to 4 different procedures with unknown, and probably, different long-term outcomes? Did the patients who underwent a Blair incision (group 1) receive additional treatment when the authors found that the outcomes in this group were worse than the outcomes in the other groups? Particular attention should be paid to these research ethics questions. Fourth, in the present study, the criterion for esthetic evaluation was not clear (their Table 2). We assumed that the authors calculated the mean esthetic score on a simplistic basis. The patient’s self-assessment (subjective evaluation) was mixed with the assessment by 3 third persons (objective evaluation). Hence, the ratio of patient to thirdperson evaluators was 1:3, converting the mean score to a weighted arithmetic mean. In general, the subjective and objective evaluation scores should not be pooled in the same analysis. Moreover, it is unknown who was the surgeon evaluator. A recent study has indicated a significant difference between disfigured persons and reconstructive surgeons regarding their expectations for the given treatment.4 Therefore, the surgeon evaluator should not have been the treating surgeon. Fifth, as with other outcome research, it is unclear whether the third persons can be representative of public eyes. From the psychological theory, an individual might develop a “self-fulfilling prophecy”: the incorporation of the perceiver’s expectations and behavior into his or her selfconcept, because of an interaction between that individual and the perceiver. Public opinions of the postoperative facial appearance could, therefore, affect patient satisfaction and/or self-concept.5,6 A recent British study showed that scar satisfaction after parotidectomy was high, regardless of the incision type (a Blair incision vs a facelift inci-