Abstract
Introduction
The proper visualisation of the larynx is required for the diagnostic assessment and therapeutic intervention. The most significant challenges for surgeon is to visualise the anterior commissure of the glottis region. The aim of this study is to record the preoperative laryngoscore in patients posted for endolaryngeal surgery and to assess preoperative predictors for intraoperative difficult laryngeal exposure by correlating with preoperative laryngoscore.
Design
Prospective, Cross-sectional, Observational study.
Setting
Department of Otorhinolaryngology in a tertiary care teaching facility.
Subjects
150 patients were included with an endolaryngeal disease who were planned for surgery with age > 18yrs.
Methodology
In 150 subjects preoperative laryngoscore was calculated, which comprised 11 parameters including thyromental distance, mandibular prognathism, macroglossia, micrognathia, trismus, inter incisor gap, degree of neck flexion-extension, history of prior open-neck surgery or radiotherapy, upper jaw dental status, modified Mallampati score and body mass index in order to produce a total score out of a possible maximum score of 17. According to the anterior commissure visualisation all patients were categorised into five classes, ranging from class 0 to class IV during surgery. The laryngoscore parameters were assessed and compared statistically with five classes of intraoperative anterior commissure visualisation.
Result
Out of 150 patients 70 (46.6%) were having 3–4 laryngoscore, followed by 45 (30%) patients with 5–6 laryngoscore. Total 123 (82%) patient had class 0,1 and 2 intraoperative anterior commissure visualisation while 27 (18%) had class 3 and 4 visualisation. If laryngoscore was either less or equal to 5, 90% of the patients had excellent laryngeal exposure whereas only 10% of the patients had challenging laryngeal exposure. At univariate analysis, thyromental distance, degree of neck flexion/extension, and modified Mallampati classification were found statistically significant for difficulty of anterior commissure visualisation independently.
Conclusion
A sound, easy and valid preoperative laryngoscore may be significantly helpful in identifying intraoperative difficult laryngeal exposure. This may prevent inadequacy of surgery, abandon of surgery, intra operative complication, and medico-legal cases for laryngologist.
Keywords: Laryngoscore, Anterior commissure, Difficult laryngeal exposure, Good laryngeal exposure
Introduction
The larynx and vocal folds perform multiple functions related to respiration, protection of the lower airway, fixation of the chest, and phonation [1]. Laryngeal diseases are common due to the habit of voice abuse, voice misuse, alcohol drinking, tobacco smoking, and human papillomavirus [2]. The proper visualisation of the larynx up to anterior commissure is required for diagnostic assessment and therapeutic. intervention. The diagnostic indication includes vocal polyp, vocal nodule, Reinke’s edema, mucous retention cyst, contact granuloma, and vocal fold paralysis. The therapeutic indication includes microlaryngeal surgery, foreign body removal, a biopsy of growth, and laryngeal framework surgery [3]. Due to the anterior commissure’s vulnerability to tumor spread the tumor invasion of the laryngeal skeleton is made possible by the absence of periosteum at the area of insertion [4]. The most significant challenges for the surgeons are the visualisation of the anterior commissure of glottis, the inappropriate size of an endotracheal tube, and the prominent teeth of the patients [5]. A laryngoscope with a triangle form that matches the curve of the vocal cord anterior commissure, the posture of the patient, external laryngeal counter pressure, and internal laryngeal distension are the typical prerequisites for good exposure [6]. Difficulty in visualising the larynx leads to the ineffective treatment for both benign and malignant tumors, damage to the normal microstructure of the vocal cords, which can result in abandoning the procedure, performing incomplete surgery, and needless stress to the natural microstructure of the vocal folds. There is a requirement for a grading system that enables us to anticipate potential difficulties with laryngoscopy visualisation [7]. There is various preoperative evaluation of patients such as medical age, gender, surgical history, physical assessment and various parameters of cervical radiography film [8]. The aim of this study is to record preoperative laryngoscore in patients posted for endolaryngeal surgery as well as assess the preoperative predictors for intra-operative difficult laryngeal exposure by correlating preoperative laryngoscore.
Materials and Methods
This prospective, cross-sectional descriptive research study was conducted in the department of otorhinolaryngology of a tertiary teaching hospital from July 2021 to December 2012 after taking clearance from institutional ethical and research committee. The sample size was calculated by formula suggested by Snedecor GW et al. with standard prevalence taken as 50%, which gave minimum sample size of 96. Total 150 patients of more than 18 years planned for endolaryngeal surgery were included in present study after obtaining written informed consent with exclusion of the patients who had cranial or cervical cause of restricted neck movements. The inter incisor gap ,thyromental distance, mandibular prognathism, macroglossia, micrognathia, trismus,, degree of neck flexion-extension, history of prior open-neck surgery or radiotherapy, upper jaw dental status, Mallampati’s modified score and body mass index were the 11 parameters that made up the preoperative laryngoscore used to evaluate 150 patients [Table 1]. Laryngoscore criteria were assessed in order to produce a total score out of a possible maximum score of 17. We were able to assess laryngoscore criteria in average 10–15 min in every patient comfortably. Based on intraoperative anterior commissure visualisation, 150 patients were divided into five classes:class 0 for complete AC visualisation using large-bore laryngoscopes in the Boyce-Jackson position, class I for complete AC visualisation with external laryngeal counter pressure, class II for complete AC visualisation using small-bore laryngoscopes in the flexion-flexion position, class III as class II using small-bore laryngoscopes and class IV as impossible AC visualisation. Intraoperative assessment of laryngeal exposure was done by otorhinolaryngologist with minimum 5 years surgical experience after passing postgraduation. Class 0–I–II patients are considered good laryngeal exposures (GLE) and Class III–IV patients are considered difficult laryngeal exposures (DLE). Preoperative laryngoscore was compared among the five classes of intraoperative anterior commissure visualisation. The data was collected and entered in MS excel 2010 and statistical analysis was performed using SPSS 22. Data was analysed using Chi- square test and Fisher exact test. If p < 0.05, then data was considered significant.
Table 1.
Parameters and scoring of Laryngoscore
| PARAMETERS | SCORE |
|---|---|
| Interincisor gap | > 4 cm /<4 cm = 0/1 |
| Thyromental distance | > 6.5 cm/6.5-6 cm/<6 cm = 0/1/2 |
| Upper jaw dental status | Edentulous/partial/normal/ Prominent superior teeth 0/1/2/3 |
| Trismus | Absent/Present = 0/1 |
| Mandibular prognathism | Absent/Present = 0/1 |
| Macroglossia | Absent/Present = 0/1 |
| Micrognathia | Absent/Present = 0/1 |
| Degree of neck flexion- extension | > 90/90 − 80/<80 = 0/1/2 |
| H/O previous neck surgery/radiation | Nil/treated = 0/1 |
| Modified Mallampati’s score | Class 1/2/3/4 = 0/1/2/3 |
| BMI | < 25/>25 = 0/1 |
Results
Out of 150 patients most of the patients were male with an M: F ratio 10.5:1. In the present study most of the patients that is 68 (45%) belong to the age group of more than 60 years followed by 52 (34.6%) patients in age group 40 to 60 years. In the present study most of the patients that is 68 (45.3%) were addicted to smoking followed by 61 (40.6%) patients who were addicted to smokeless tobacco. In the present study most of the patients that is 84 (56%) belonged to rural areas. In present study, the most common presenting complaint was change of voice that is present in 51 (34%) patients, followed by difficulty in swallowing in 40 (26.6%) patients. In present study the maximum 85 (56.7%) patients reported to the hospital within 3 months of onset of symptoms. In present study the most common co-morbidity was hypertension that is present in 41 (27.3%) patients followed by diabetes mellitus in 22 (14.7%) patients of study population. Preoperative laryngoscore was evaluated in all150 patients [Table 2]. It was observed that 87 (58% ) of the patient have inter incisor distance was 3.1- 4.0 cm followed by 49 (32.7%) have > 4 cm. The Thyromental distance was > 6.5 cm in 136 (90.7%) patients. Upper jaw dental status was normal in 59 (39.3%) patients while partial in 45 (30%) patients. The degree of neck movement was 80–90 degree in 87 (58%) of patients while it was > 90 degree in 32 (21.3%) patients.The modified Mallampati’s score was class II in 70 (46.6%) and class 1in 54 (36%) of patients. The body mass index was less than 25 kg/m2 in 122 (81.4%) of patients and > 25 in 18.6% patients.The calculated laryngoscore was 3–4 in 70 (46.6%) while 5–6 in 45 (30%) of patients. Trismus was observed in 14 (9.3%) patients. Macroglossia was found in 1 patient. History of previous neck surgery i.e. tracheostomy was found in 28 (18.6%) patients and history of previous neck radiation was found in 6 (4%) patients. There was no patient who had mandibular prognathism and micrognathia. In our study after recording the score of preoperative laryngoscore as shown in Table 2, all the 150 study patients were categorised into 5 Classes, on the basis of intraoperative anterior commissure visualisation [Table 3]. Class 0–II patients are considered good laryngeal exposures (GLE) and Class III–IV patients are considered difficult laryngeal exposures (DLE) as shown in Table 4. All the individual parameters of laryngoscore was compared with classes of intraoperative score and observed that in independent variable only thyromental distance, degree of neck movement and mallampati’s classification were found statistically significant [Tables 5, 6 and 7]. Other parameters of laryngoscore were not significant statistically for difficulty laryngeal exposure. In our study when total score of preoperative laryngoscore was compared with intraoperative anterior commissure visualisation then a cut off value of 5 from total score of laryngoscore was used for distinguishing between excellent laryngeal exposure and poor laryngeal exposure. In our study, 90% of the patients had excellent laryngeal exposure if the laryngoscore were equal or less than5, whereas only 10% of the patients had challenging laryngeal exposure. If the laryngoscore were > 5, 22% of the people in the research group experienced poor laryngeal exposure, whereas the remaining 78% experienced excellent laryngeal exposure [Table 4].
Table 2.
Distribution of patients based on preoperative laryngoscore findings (N = 150)
| Laryngoscore | Male | Female | Number of patients |
|---|---|---|---|
| 0–2 | 18 | 0 | 18(12%) |
| 3–4 | 62 | 8 | 70(46.6%) |
| 5–6 | 40 | 5 | 45(30%) |
| 7–8 | 15 | 0 | 15(10%) |
| 9–10 | 2 | 0 | 2(1.3%) |
| Total | 137 | 13 | 150(100%) |
Table 3.
Distribution of patients based on intraoperative visualisation of anterior commissure (N = 150)
| Intraoperative visualization of the anterior commissure | Male | Female | Number of patients |
|---|---|---|---|
| Class 0 | 24 | 3 | 27(18%) |
| Class 1 | 56 | 7 | 63(42%) |
| Class 2 | 41 | 2 | 43(28.7%) |
| Class 3 | 7 | 0 | 7(4.7%) |
| Class 4 | 9 | 1 | 10(6.7%) |
| Total | 137 | 13 | 150(100%) |
Table 4.
Showing laryngoscore cut off score to excellent laryngeal exposure and poor laryngeal exposure (N = 150)
| Laryngoscore cut off value | Intraoperative score | ||
|---|---|---|---|
| Poor laryngeal exposure (n = 19) | Excellent laryngeal exposure (n = 131) | Total (n = 150) | |
| 0–5 | 12 (10%) | 106 (90%) | 118(100%) |
| 6–10 | 7 (22%) | 25 (78%) | 32(100%) |
Table 5.
Comparison of Intraoperative score of patient with Thyromental distance finding (N = 150)
| Intraoperative score | Thyromental distance (cm) | Total | ||
|---|---|---|---|---|
| > 6.5 | 6-6.5 | < 6 | ||
| Class 0 | 26 | 1 | 0 | 27(18%) |
| Class 1 | 58 | 5 | 0 | 63(42%) |
| Class 2 | 39 | 3 | 1 | 43(28.7%) |
| Class 3 | 6 | 1 | 0 | 7(4.7%) |
| Class 4 | 7 | 2 | 1 | 10(6.7%) |
| Total | 136 | 12 | 2 | 150(100.0%) |
| P value | 0.031 | |||
Table 6.
Comparison of Intraoperative score of patient with degree of neck flexion and extension finding (N = 150)
| Intraoperative score | Degree of Neck flexion extension | Total | ||
|---|---|---|---|---|
| > 90 | 90 − 80 | < 80 | ||
| Class 0 | 4 | 16 | 7 | 27(18%) |
| Class 1 | 14 | 42 | 7 | 63(42%) |
| Class 2 | 10 | 18 | 15 | 43(28.7%) |
| Class 3 | 3 | 4 | 0 | 7(4.7%) |
| Class 4 | 1 | 7 | 2 | 10(6.7%) |
| Total | 32 | 87 | 31 | 150(100.0%) |
| P value | 0.014 | |||
Table 7.
Comparison of Intraoperative score of patient with Modified Mallampati’s score finding (N = 150)
| Intraoperative score | Modified Mallampati’s score | Total | |||
|---|---|---|---|---|---|
| Class I | Class II | Class III | Class IV | ||
| Class 0 | 9 | 12 | 6 | 0 | 27(18%) |
| Class 1 | 23 | 33 | 7 | 0 | 63(42%) |
| Class 2 | 15 | 20 | 8 | 0 | 43(28%) |
| Class 3 | 3 | 3 | 1 | 0 | 7(4.7%) |
| Class 4 | 4 | 2 | 3 | 1 | 10(6.7%) |
| Total | 54 | 70 | 25 | 1 | 150(100.0%) |
| P value | 0.021 | ||||
Discussion
In this present study out of 150 patients, 137 (91.3%) were male and 13 (8.7%) were female. In our study female presented less in the OPD so there was not a significant sample size of the female patients. This corresponds to the study done by the Singhal et al. on 50 patients of endolaryngeal disease which also shows the male predominance [9]. A chronic inflammatory process is necessary for the formation of tumors. Men are most commonly presented in the laryngoscopy examination due to the habit of tobacco and alcohol consumption [10]. In this study, the inclusion criteria of age of patients was any patient above 18 years. The majority of patients 54 (36.6%) was from age group of 61 years to 70 years. In our study majority of the patient had malignancy which is common in older age group. The study was carried out in the Regional Cancer Centre showed median age of laryngeal carcinoma at presentation was 65 years [11]. The prospective study done by the Singhal et al. on 50 patients in which they identify demographic detail and etiology of the benign laryngeal lesion and found 21–30 years was the most common age group in their study as the lesion was only benign [9]. In our study, it was observed that maximum patients addicted to smoked tobacco form 68 patients (31.7%). It was favoured by an institutional study showed that tobacco chewing and tobacco smoking is associated with laryngeal carcinoma [12]. Maximum patients in our study belonged to rural areas (56.0%) followed by 31.3% in urban area. In our study most of the patient belongs to village population comprising of farmers and labourers. This corresponds to the study done by the Bath S on 110 patients of hoarseness of voice and found maximum patients belongs to the rural areas [13]. In present study, the most common presenting complaint was hoarseness of voice (51cases, 34%), followed by dysphagia (40 cases, 26.6%) and odynophagia (32cases, 21.3%). Our study was favoured by the study done by the Singhal et al. in which hoarseness was present in all patients (100%) the patients in laryngeal lesion [9]. In our study, it was found, maximum patients 69 (46.0%) reported to the hospital within 1–3 months of onset of symptoms. The maximum duration was 4 year and minimum duration was 7 days in present study. It was because the change in voice was early reported by the patients, colleges and by the family members which lead them early reporting to the hospital. Baitha S conducted a study on 110 patients of hoarseness of voice from day 1 to 5 years and found most of the patients (50%) presented under three months of duration [14].
Total laryngoscore findings were measured and it was observed that out of the total 150 patients, maximum patients 70 (46.6%) were having 3–4 laryngoscore, followed by 45 (30%) patients with 5–6 laryngoscore, followed by 18 (12%) patients with 0–2 laryngoscore, 15 patients were having 7–8 laryngoscore and 2 (1.3%) patients having 9–10 laryngoscore. The thyromental distance, degree of neck flexion and extension and mallampatti score was compared with the intraoperative score score and these are statistically significant (p < 0.05). Kim H. W et al. conducted a study to observe the ability of a ratio of the neck circumference to thyromental distance (NC/TM) in 123 obese and 125 non-obese patients and to predict difficult intubation in obese patients and compare NC/TM ratio with the difficult intubation and found NC/TM ratio were independently predicting (p < 0.001) the difficult intubation revealed by Multivariate analysis [15]. The study conducted by Arjun et al. in 32 patients and in which they compare the degree of neck movement with the intraoperative score and found degree of neck movement (p = 0.007) was significant parameter for preoperative predictor for difficult laryngeal exposure and they also compare modified Mallampati’s score with the intraoperative score and found Mallampati score (p = 0.007) was significant parameter for preoperative predictor for difficult laryngeal exposure [7]. Similar study conducted by piazza et al. in 319 patients and found Mallampati score (p > 0.05) was not a statistically significant preoperative predictor for difficult laryngeal exposure [16].
The interincisor distance, upper jaw dental status, and body mass index (BMI) of the patients was compared with the intraoperative score and these are statistically not significant (p > 0.05). In our study, maximum patients had > 4 cm adequate interincisor distance. The reduce interincisor distance causes difficulty in introducing and manipulating the laryngoscope blade and difficulty in visualising the normal anatomy around the laryngoscope. A study was conducted by Arjun AP et al. carried out a study in 32 patients undergoing microlaryngoscopy and compare interincisor distance with intraoperative score and found IIG was not a significant (p > 0.05) parameter in their study for preoperative predictor for difficult laryngeal exposure [7]. Another study was conducted by piazza et al. in which they evaluated 319 patients before microlaryngoscopy that included 11 parameters and compare interincisor distance with intraoperative score and found interincisor distance was a significant (p < 0.001) parameter in their study for preoperative predictor for difficult laryngeal exposure [15]. In our study, a maximum number of patients had normal upper jaw dental status. The prominent upper teeth may block the pathway to glottis and interfere with the laryngoscope blade. There is also the risk of tooth damage [16]. The study conducted by Roh JL et al. in which they investigated 73 patients for a physical examination and compare difficult laryngeal exposure with the body mass index and showed a significant (p < 0.038) correlation with the difficult laryngeal exposure [17]. The intraoperative score was compared with laryngoscore of 150 patients In the study by Arjun et al., when they took a cut off score of Laryngoscore < 6 then they find excellent laryngeal exposure in 94% of patients and difficulty in laryngeal exposure in 6% of patients. Whereas a score of > 6 had difficulty in laryngeal exposure in 54% of the patients and excellent laryngeal exposure in 46% of patients [5]. In the study by piazza et al., excellent laryngeal exposure was achieved in 94% of patients when the Laryngoscore value was < 6, whereas only 6% of patients experienced problems with laryngeal exposure. 60% of patients had excellent laryngeal exposure when the Laryngoscore value was > 6, while 40% of patients had problems with laryngeal exposure. [15].
Till now there is not an accepted, standard scoring system thus this study can provide information of difficult laryngoscopy and contribute in the improvement of preoperative assessment for performing an effective operative endolaryngeal surgery.
Conclusion
There is a requirement of a grading system that enables us to anticipate potential difficulties with laryngoscopy visualisation. Limited number of studies have been done in Indian population on a preoperative scoring system. So present study is an effort for improving the preoperative laryngoscore which is easy to perform. It will give great benefit to the treating surgeons to preoperatively predict the difficult laryngeal exposure before endolaryngeal surgery. Our study suggest that neck flexion, thyromental distance and Mallampati score has only significant p values but further studies with great number of patients are required to justify present laryngoscore validity.
Declarations
Conflict of interest
Nil.
Financial support – Nil.
Footnotes
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