COMPLICATIONS OF SUSPENSION LARYNGOSCOPY

Ann Otol Rhinol Laryngol 111:2002 Ann Otol Rhinol Laryngol 111:2002 REPRINTED FROM ANNALS OF OTOLOGY, RHINOLOGY & LARYNGOLOGY November 2002 Volume 111 Number 11 COPYRIGHT 2002, ANNALS PUBLISHING COMPANY COMPLICATIONS OF SUSPENSION LARYNGOSCOPY JENS PETER KLUSSMANN, MD ROBERT KNOEDGEN, DDS, MD CLAUS WITTEKINDT, MD MICHAEL DAMM, MD HANS EDMUND ECKEL, MD KLAGENFURT, AUSTRIA Although suspension laryngoscopy (SL) is routinely used in operative laryngology, no prospectively gathered data on the complications of this procedure have so far been available. We prospectively analyzed 339 consecutive procedures for interventionrelated complications. The survey included preoperative dental status and assessment of postoperative dental, mucosal, and nerve injuries. Minor mucosal lesions were found in 75% of all patients. All healed spontaneously within a few days. Dental injuries occurred in 6.5% of all patients. These were more frequent in therapeutic laryngoscopy than in diagnostic procedures (6.8% versus 6.0%). Highly significant correlations were found between dental injury rate and preoperative dental disease (p <.04) and grade of periodontitis (p <.001). Temporary nerve lesions were observed in 13 patients (9 of the lingual nerve and 4 of the hypoglossal nerve). Although minor complications frequently occur during SL, it is a relatively safe procedure with a low risk of significant morbidity. KEY WORDS dental injury, perioperative complications, suspension laryngoscopy. INTRODUCTION Although suspension laryngoscopy (SL) is routinely used in diagnostic and operative laryngology, only limited data on the complications of this procedure have so far been available in the literature. Most studies assessed complications retrospectively without preoperative examination. Reported rates of minor complications such as dental injuries or minor bleeding range from 9.1% 1 to 31% 2 in patients who have undergone direct laryngoscopy alone or in conjunction with other endoscopic procedures. Major complications, defined as complications requiring hospitalization, were found in 19.5%. 3 Hill et al 4 reported a 1.2% incidence of airway complications requiring reintubation following SL. Atkins et al 1 had a 0.4% rate of emergency tracheotomy after direct laryngoscopy. Other life-threatening complications, such as pneumothorax, cardiovascular complications, and major bleeding, have also been reported. 5-7 Dental injuries following laryngotracheal intubation for general anesthesia have been studied extensively, and a rate of 0.1% has been assessed. 8,9 In contrast, there are no prospective data for dental injuries under the conditions of SL. This lack is somewhat surprising, as dental damage during that procedure is well known and dental protection is routinely recommended. From the Departments of Otorhinolaryngology Head and Neck Surgery (Klussmann, Wittekindt, Damm, Eckel) and Dentistry (Knoedgen), University of Cologne, Cologne, Germany. Supported by funding from the Jean Uhrmacher Foundation and from the Köln Fortune-Programme of the Faculty of Medicine, University of Cologne (No. 93/2001). Presented at the meeting of the American Laryngological Association, Boca Raton, Florida, May 10-11, 2002. CORRESPONDENCE Hans Edmund Eckel, MD, HNO-Abteilung, Landeskrankenhaus Klagenfurt, St Veiter Str 47, A-9020 Klagenfurt, Austria. 972 Injuries of the lingual nerve and hypoglossal nerve have been described in case reports 10 ; however, general incidences have not been evaluated for SL. The aim of this study was to assess the rate of and associated risk factors of intervention-related complications of SL in a prospective and well-defined series. MATERIALS AND METHODS We prospectively included all patients more than 18 years of age who were to undergo SL for any reason between August 18, 1997, and August 10, 1998, at the Department of Otorhinolaryngology Head and Neck Surgery of the University of Cologne. The study population consisted of 339 consecutive patients. There were 252 men (74%) and 87 women (26%). The patients ages ranged from 29 to 86 years, with an average of 59 years. Interventions were performed for the diagnosis or treatment of malignant tumors in 48% and noncancerous lesions (including control endoscopies following previous transoral surgery for laryngeal carcinomas) in 52%. The different treatment conditions are shown in Table 1. Suspension laryngoscopy was performed in 265 cases (78%) with the use of conventional cold instruments, mostly in a diagnostic approach, and in 74 cases (22%) in a laser surgery setting. All interventions were performed under general anesthesia. In 82% of cases, endotracheal

973 Klussmann et al, Complications of Suspension Laryngoscopy 973 TABLE 1. TREATMENT CONDITIONS Patients No. % Interventions for malignancies 164 48 Tumor of larynx 69 21 Transglottic 12 4 Supraglottic 23 7 Glottic 32 9 Subglottic 2 1 Tumor of hypopharynx 33 10 Other carcinoma of upper aerodigestive tract 62 18 Interventions for benign lesions 175 52 Keratosis of larynx 24 7 Chronic laryngitis 12 4 Vocal cord granuloma 5 1 Vocal cord polyp 15 4 Vocal cord cyst 7 2 Laryngeal papillomatosis 4 1 Vocal cord palsy 16 5 Vocal cord edema 9 3 Epiglottitis 3 1 Botox injection 4 1 Laryngeal or subglottic stenosis 5 1 Zenker s diverticulum 2 1 Normal larynx (control laryngoscopy) 47 14 Others 22 6 Total 339 100 intubation was used, and in 18%, jet ventilation was chosen. A standard dental guard made from silicone was used for dental protection in all patients. All patients were examined before operation by one of the contributing head and neck surgeons (J.P.K., C.W., M.D., H.E.E.) and by a dentist (R.K.). The survey included preoperative dental examination in addition to complete clinical otorhinolaryngological examination. Within 24 hours of surgery, all patients were reexamined for intervention-related complications. Only injuries not related to resection or biopsy were counted as postoperative dental, mucosal, and nerve injuries. Standardized forms for recording data were used. Patients with nerve injuries were followed up for 15 months. Factors associated with complication status were selected on cross-tabulations, which were analyzed by the use of a χ 2 test or t-test with the SPSS Base System, version 9.0 (SPSS, Chicago, Illinois). An initial significance level of α 0.05 was chosen. RESULTS Minor mucosal lesions were found in 75% of all patients after SL. In the 339 patients, a total of 518 mucosal injuries were counted. The distribution and types of mucosal lesions are shown in Table 2. Fiftyfive percent of all lesions were erosions of the mucosa; all of these lesions were minor and healed spontaneously within a few days. However, there were also more severe injuries such as hematomas, which accounted for 29% of all lesions. Thirteen of the counted hematomas were located in the tongue, as shown in the Figure, A. Patients with this kind of complication had complaints for several weeks. Less frequent were lesions such as bleeding (7%), fissures (3%), and mucosal swelling (5%), as shown in Table 2. Most of the evaluated mucosal lesions were found in the oral cavity: 172 of 339 patients (51%) had a mucosal lesion at that site. Overall, in the oral cavity, 265 lesions were counted, which constituted 51% of all mucosal lesions (Table 2). Most mucosal injuries of the oral cavity were located at the right or medial maxilla and accounted for 31% of all mucosal injuries. Injuries of the tongue (6%) were often hematomas (see Figure, A) or erosions. Some of those mucosal erosions, especially on the lateral part of the tongue, were painful and deep, as shown in the Figure, B. The oropharynx was found to be the second most TABLE 2. TYPES AND LOCATIONS OF ALL COUNTED MUCOSAL LESIONS (N = 518) Location Bleeding Fissure Erosion Hematoma Swelling Total Lips 4 (0.8%) 1 (0.2%) 62 (12%) 10 (2%) 15 (3%) 92 (18%) Upper 1 0 17 7 2 27 Lower 3 1 45 3 13 65 Oral cavity 31 (6%) 11 (2%) 173 (33%) 44 (8%) 6 (1%) 265 (51%) Right maxilla 17 4 60 4 0 85 Medial maxilla 14 6 57 0 0 77 Right tongue 0 1 12 13 4 30 All others 0 0 44 27 2 79 Oropharynx 0 6 (1%) 45 (9%) 98 (19%) 7 (1%) 156 (30%) Right soft palate 0 1 23 70 7 101 Left soft palate 0 1 5 18 0 24 All others 0 4 17 10 0 31 Hypopharynx 0 0 5 (1%) 0 0 5 (1%) Total 35 (7%) 18 (3%) 285 (55%) 152 (29%) 28 (5%) 518 (100%)

974 Klussmann et al, Complications of Suspension Laryngoscopy 974 A B C D Typical complications after suspension laryngoscopy. A) Massive hematoma of tongue. B) Erosion of lateral part of tongue. C) Swelling of lower lip. D) Severe tooth loosening at front part of maxilla. common site for mucosal lesions. The incidence of oropharyngeal lesions was 32% (110 of 339 patients). The most frequent injuries at that site were hematomas, which constituted 98 of 156 oropharyngeal lesions. They were predominantly located on the right side of the soft palate (101 of 165 oropharyngeal lesions). Lip injuries were observed in 92 patients (27% of all patients and 18% of all counted mucosal lesions). In contrast to the oral cavity, in which most lesions were located at the upper jaw, most lip injuries were located on the lower lip (65 of 92 lesions, ie, 70.7%). Most of these injuries were superficial erosions. More severe swellings of the lower lip, as shown in the Figure, C, occurred in 3 patients. Mucosal injuries of the hypopharynx were rarely observed; only 5 of 518 lesions (1%) were located at that site. To determine the influence of the operative setting, we compared mucosal injuries in diagnostic SL and therapeutic SL. For diagnostic SL and therapeutic SL, the rates of intervention-related mucosal lesions were 77% (205 of 265) and 68% (50 of 74), respectively. However, this difference was not significant (p =.08). The risk of mucosal lesions was higher for those patients who underwent SL under endotracheal intubation (76%) than for those who underwent SL under jet ventilation (57%; p <.05). Preoperative assessment of the dental status of all 339 patients revealed 65 patients (19%) as edentate and 9 (3%) as having no evidence of odontopathy. Of the remaining patients, 177 had periodontal disease only, 1 had carious teeth only, and 87 had both. Of the 264 patients with periodontal disease, 8% had gingivitis, 40% had superficial periodontitis, and 53% had deep periodontitis. Overall, dental injuries were observed in 6.5% of all patients who underwent SL. In these 22 patients with intervention-related dental complications, 35 teeth were injured and 39 lesions were observed. The types of dental injures and the preoperative dental status are shown in Table 3. The most frequently observed dental injuries were loosening of one or more teeth (43%). Most of the loosenings were severe, and the teeth could not be preserved. The Figure, D, shows a typical severe tooth loosening that occurred after SL, located in the upper front part of the mouth. Fractures of the teeth and roots often required subsequent dental treatment and were observed in 24% of all dental injuries. Avulsions were found in 13% of the lesions. Other dental injuries (24%) included damage of fixed dental prostheses and fractures of dental fillings. Most dental injuries were located in the

975 Klussmann et al, Complications of Suspension Laryngoscopy 975 TABLE 3. TYPES OF DENTAL INJURIES AND PREOPERATIVE PERIODONTAL STATUS Superficial Deep Healthy Gingivitis Periodontitis Periodontitis Total Dental Injuries (n = 38) No. % No. % No. % No. % No. % Avulsion 0 0 0 0 0 0 5 13 5 13 Mild dental loosening 0 0 0 0 1 3 2 5 3 8 Severe dental loosening 0 0 0 0 0 0 13 34 13 34 Tooth or root fracture 0 0 1 3 0 0 8 21 9 24 Others 0 0 2 5 0 0 7 18 9 24 Total 0 0 3 8 1 3 35 92 38 100 upper front part of the mouth (60%), and there was a trend for the right side to be affected (Table 4). Ninety-two percent of all evaluated dental injuries occurred in patients who had been found before operation to have deep periodontal disease. The rate of dental injuries in this subgroup of patients was 13.3%. In contrast, no dental injury occurred in patients who had healthy teeth before SL. Significant correlations were therefore found between the dental injury rate and preoperative dental disease (p <.04) and grade of periodontitis (p <.001). Comparing the operative settings, we found dental complications to be more frequent in therapeutic laryngoscopy than in diagnostic procedures (6.8% versus 6.0%); however, the difference was not significant (p =.91). The rate of dental injuries was higher in patients who underwent SL under endotracheal intubation (6.8%) than in those in whom jet ventilation was performed (3.6%); however, the difference was not significant (p =.51). Temporary nerve lesions were observed in 13 patients (3.8%). Nine patients had dysfunction of the lingual nerve, and 4 of the hypoglossal nerve. Patients with lingual nerve injury complained of tongue numbness, mostly localized to the right anterolateral aspect of the tongue. The duration of the complaints ranged from 1 to 60 weeks, with a median of 4 weeks (SD, 19.1 weeks). In all cases of hypoglossal nerve dysfunction, the right side was affected. The duration of the hypoglossal nerve dysfunction ranged from 6 to 16 weeks (median, 8 weeks). In our series, no subject had airway complications that required reintubation or tracheotomy. DISCUSSION Suspension laryngoscopy is routinely used in diagnostic and operative laryngology. However, data on intervention-related complications are rare. The aim of this study was to address this issue and to assess all detectable complications related to SL in a prospective and well-defined series. We found no life-threatening complications and no intervention-related deaths. Therefore, we conclude that SL is a relatively safe procedure, and confirm similar data published earlier. 11 In contrast, we found mucosal lesions in 75% of our patients, which is a fairly high rate as compared to an earlier study. 2 In view of the number of included subjects and especially because of the prospective study design and our careful postoperative examination within 24 hours after endoscopy, we believe this estimate to reflect the true rate of mucosal lesions after SL. Because all of these lesions healed spontaneously without further treatment, they constitute no severe sequelae of endoscopy. Furthermore, the knowledge of mechanisms that lead to mucosal injuries will help one to avoid them and may be helpful in learning the endoscopic technique of SL. Most lip lesions were located on the lower lip (Table 2 and Figure, C). These lesions often occur during insertion of the laryngoscope, if the lower lip is slipped over the lower teeth and becomes trapped between the teeth and the laryngoscope. In the same way, the tongue can be trapped between the frontal or lateral teeth and the laryngoscope and incur lesions such as that shown in the Figure, A. Such tongue hematomas lead to complaints that last for several weeks and should be avoided. Furthermore, mucosal injury seems to be related to the duration of intervention, as the rate was decreased in procedures performed under jet ventilation, which normally have a shorter duration. Interestingly, most mucosal, dental, and nerve lesions were located on the right side of the patient, reflecting the right-handedness of most surgeons. TABLE 4. NUMBERS AND LOCATIONS (FDI WORLD DENTAL FEDERATION SCHEMA) OF INJURED TEETH No. of injured teeth 1 2 4 6 6 1 1 Maxilla 18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28 Mandible 48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38 No. of injured teeth 4 1 2 4 1 1 1

976 Klussmann et al, Complications of Suspension Laryngoscopy 976 For laryngotracheal intubations, dental injuries have been studied extensively, and most authors found rates of about 0.1%. 8,9,12 In contrast, making an immediate postoperative assessment, Chen et al 13 found a rate of 12% for minimal dental injuries after general anesthesia. However, for SL, no prospectively gathered data have been available so far. The dental injury rate has been retrospectively assessed to be 1%. 14 In contrast, we found an overall dental injury rate of 6.5%. Therefore, SL may have a significantly higher risk for dental complications than laryngotracheal intubation. However, this conclusion may be limited by differences in the study populations concerning dental status and age. In our series, subjects with deep periodontal disease had a highly increased risk of dental injury during SL (p <.001; odds ratio, 9.86; 95% confidence interval, 2.86 to 34.01). Therefore, in these patients, if the teeth are in a condition to be preserved, special dental guards may be useful. 11,15-17 Otherwise, if periodontitis is so severe that the teeth have to be removed, it may be better to remove them before operation or during endoscopy with the patient s consent. On the other hand, it should be pointed out that in our study, dental injuries in subjects with healthy teeth were not observed. Dental protection during SL is routinely used for the upper jaw because of the assumption that most pressure is applied to the upper front teeth. Interestingly, we found 40% of all dental injuries to occur in the lower jaw, and surgeons may not be sufficiently aware of this specific risk. The rate of dental injury was increased in therapeutic interventions, such as endoscopic oncological procedures. In such interventions, the need for repeated readjustment of the endoscope is likely to contribute to the elevated rate of complications. Nerve injuries after SL are known from several case reports. We first report here the incidence of this complication after SL. We found a 2.6% rate for lingual nerve injury with a median duration of 4 weeks and a 1.1% rate for hypoglossal nerve injury with a median duration of 8 weeks. Although these were temporary lesions, we recommend that patients should be informed about these risks before operation. CONCLUSION Suspension laryngoscopy carries a higher risk for minor mucosal lesions, tooth injuries, and temporary lingual and hypoglossal nerve injuries than was previously anticipated. In contrast, the rate of life-threatening complications was lower than that reported in the literature. We conclude that SL is a relatively safe procedure. The severity of the complications compares favorably to that of complications of open surgery and qualifies SL as a routine surgical approach to a wide variety of laryngeal disorders. 1. Atkins JP Jr, Keane WM, Young KA, Rowe LD. 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Cardiac complications of suspension laryngoscopy. Fact or fiction? Arch Otolaryngol Head Neck Surg 1986;112:860-2. 8. Warner ME, Benenfeld SM, Warner MA, Schroeder DR, Maxson PM. Perianesthetic dental injuries: frequency, outcomes, and risk factors. Anesthesiology 1999;90:1302-5. REFERENCES 9. Field JM. Dental injuries during general anaesthesia. Br Dent J 1996;181:11. 10. Gaut A, Williams M. Lingual nerve injury during suspension microlaryngoscopy. Arch Otolaryngol Head Neck Surg 2000;126:669-71. 11. Armstrong M, Mark LJ, Snyder DS, Parker SD. Safety of direct laryngoscopy as an outpatient procedure. Laryngoscope 1997;107:1060-5. 12. Mutlu GM, Factor P. Complications of mechanical ventilation. Respir Care Clin N Am 2000;6:213-52. 13. Chen JJ, Susetio L, Chao CC. Oral complications associated with endotracheal general anesthesia. Ma Zui Xue Za Zhi 1990;28:163-9. 14. Levine B, Nielsen EW. The justifications and controversies of panendoscopy a review. Ear Nose Throat J 1992;71: 335-40, 343. 15. Olson GT, Moreano EH, Arcuri MR, Hoffman HT. Dental protection during rigid endoscopy. Laryngoscope 1995;105:662-3. 16. Podoshin L, Fradis M. Protecting the upper teeth during microlaryngoscopy. A new method. Arch Otolaryngol 1976;102: 439. 17. Salisbury PL III, Curtis JW Jr, Kohut RI. Appliance to protect maxillary teeth and palate during endoscopy. Arch Otolaryngol 1984;110:106-7.