ABSTRACT

Corresponding Author:
Dr. Devendra Kumar Gupta,
Head and Neck Oncosurgeon,
Army Hospital R & R,
Dhaula Kua, Delhi Cantt, New Delhi-10, India.
E-mail: docdk2000@yahoo.com

ABSTRACT

BACKGROUND

Airway management is a very important aspect during head and neck squamous cancer (HNSCC) diagnostic procedures under anaesthesia, as the upper airway is shared by the anaesthesiologist as well as the surgeon. Adequate airway management is essential during these procedures due to safety issues and cost effectiveness and also to prevent an airway emergency. There is always a question of which patients need endotracheal intubation and in whom we should avoid. We wanted to assess the merits and demerits of upper airway diagnostic procedures in HNSCC under general anaesthesia with or without endotracheal intubation and determine the factors which may lead to an airway emergency or endotracheal intubation.

METHODS

This is a retrospective observational study of consecutive HNSCC patients, who underwent diagnostic or therapeutic rigid laryngoscopy under anaesthesia between Dec 2015 till Jul 2017 (retrospective) and Aug 2017 till December 2018 (prospectively maintained database) at a tertiary referral centre. Consecutive patients of HNSCC who underwent diagnostic endoscopy under anaesthesia for biopsy or mapping of the disease were included in the study. 393 patients’ data was screened, out of which 303 patients were eligible for our study. 90 patients were excluded from the study, 30 were in stridor and 60 had a prior tracheostomy at the time of diagnostic evaluation. Various factors were evaluated for endotracheal intubation.

RESULTS

303 consecutive patients’ database was analysed. Male:Female ratio was 93:210 (1:2.3); age ranged from 27 years to 81 years; mean age was 43 years; body mass index ranged from 17-33 with median 20. The site of lesion (glottis) and prior treatment were found to be significant factors for elective intubation. Micro-laryngoscopic procedure was found to be significant for endotracheal intubation. Rest all procedures can be safely performed with total intravenous anaesthesia (TIVA).

CONCLUSIONS

Direct laryngoscopy with or without biopsy for UADT SCC is safe without intubation baring few cases. We can do a DL Scopy next day of visit to our centre in per primum, thereby reducing the waiting period and establishing diagnosis early and hence reducing overall treatment time. it is cost effective. Patients with prior cancer directed treatment need intubation because of altered anatomy and neck tissue fibrosis. ML scopy takes longer time; hence, apnoea technique is not recommended due to CO₂ retention; intermittent intubation through the laryngoscope is acceptable.

KEY WORDS

Head Neck Squamous Cell Cancer, Direct Laryngoscopy, Micro-Laryngoscopy, Total Intravenous Anaesthesia

BACKGROUND

Head and neck squamous cell carcinoma is the most common malignancy in Indian male.⁽¹⁾ Purpose of direct laryngoscopy using Jackson or Negus laryngoscope is to assess the exact extent of tumour in terms of involvement of  vallecula,

Figure 1. Typical Picture of Office Laryngoscopy in  Laryngopharyngeal Cancer Obscuring the Airway and Alarming the Surgeon and Anaesthetist

Figure 2. Algorithm of Sequence of Events of a Typical Head Neck Cancer Patient

Figure 3. Relative Diameter of Endotracheal Tube Obscuring Upper Aerodigestive Tract for Diagnostic Direct Laryngoscopy

213 were male and 90 were female. Body mass index ranged from 18- 36 Kg/m2 with a median of 22.5. 254 (83.8 %) did not require endotracheal intubation, however, 49 (16.2%) required intubation. Out of 49 required intubation 10 required a fibreoptic assisted awake intubation in view of difficult airway, all of these were post cancer directed treatment for head neck cancer. Fibreoptic assessment was performed in 203 (66.3%) patients. Tracheostomy was anticipated in 56 (18.5%) and only 9 (3%) required tracheostomy. None of the patients whom tracheostomy was not anticipated required tracheostomy. Majority of the patients were treatment naive 225 (74.3%), 36 (11.9%) were post radiotherapy, rest were post-surgery with or without chemoradiotherapy or concurrent chemoradiotherapy alone. Most of the patients were having a lesion either in hypopharynx or in larynx (Pyriform sinus- 93 (30.7%), supraglottis- 50 (16.5%), Glottis- 34(11.2%), Base of tongue- 59 (19.5%).

Majority of patients underwent direct laryngoscopy with or without biopsy – 227(71.7%), 43 (14.2%) underwent evaluation under anaesthesia for carcinoma tongue for posterior extent along with direct laryngoscopy. 43 ( 14.1%) underwent microlaryngoscopy with or without LASER resection of lesion in glottis. They were uniformly distributed in various anaesthesia indices like Mallampati, Cormack Lahane and thyromental distances. (Table 2)

On univariate analysis using SPSS version 20, site of lesion (Glottis), prior cancer directed treatment and type of procedure (Microlaryngoscopy) correlated significantly with requirement of intubation. However, on multivariate analysis microlaryngoscopy and prior treatment were the only factors which significantly affected the decision of intubation amongst this subset of patients. (Table 2)

The Odds ratio (HR) of prior treatment and microlaryngoscopy for requirement of intubation were 1.93 and 97 respectively.

DISCUSSION

Various indices which have been described may serve as important tools to preoperatively predict the airway and accordingly prepare the operative room for difficult intubation or surgical airway. The same may also help in better counseling of the patients. These tools are simple to comprehend and measure.^(7,8) All head neck surgeons should be well versed with their use to predict difficulty of direct laryngoscopy, as well as predict the exposure at microlaryngoscopy. However, for the requirement of intubation these indices did not affect significantly.

Altered anatomy is the most common factor for difficult intubation^(9,10) and was significant factor in our study also. Prior cancer directed treatment for the recurrent head neck cancer patients required intubation because of altered anatomy and neck fibrosis which significantly affected the requirement of intubation in our study (P = 0.05 95 % confidence interval 0.3% to 1.9%). Since this was a retrospective review at a single centre hence there are chances of selection bias, however treatment naïve patients can be safely taken up for diagnostic laryngoscopy without intubation.

Site of Lesion

Preoperative indirect laryngoscopy and imaging should be performed to know the site, size and extent of the lesion. It should be performed ideally by the surgeon who is going to perform diagnostic or therapeutic laryngoscopy. This indirect laryngoscopy provides the operating surgeon with the necessary information to plan for any special preparation, if required. However, other than glottis none of the other sites significantly affected the requirement of intubation-

1. Base of Tongue– Lesions on base of tongue will obscure the view of airway below and hence an apprehension to lose airway by the anaesthesiologist. If indirect laryngoscopy is done for intubation, there is a possibility of torrential bleed or the friable tumour may dislodge in the airway leading to airway emergency; hence a rigid direct laryngoscope (Kleinesaucer type) by the head neck surgeon/ ENT surgeon who has evaluated the lesion prior will have lesser chances of airway emergency.
2. Tonsil– Tonsillar lesions can be biopsied easily in an OPD setting under local anaesthesia. However, trans-oral resection with or without Robot/LASER has emerged as a major breakthrough in oropharyngeal malignancies and evaluation under anaesthesia to know the exact extent and depth is essential before undertaking the procedure. This is a short procedure and endotracheal intubation may not be necessary, as it might prolong the overall procedure time.
3. Supraglottis/Glottis– These lesions will obscure the view of vocal cords and lower airway making intubation difficult. Secondly, endotracheal tube will obscure the mapping of disease; hence evaluation by the surgeon without intubation is preferred. If intubation becomes necessary, the same can be done through direct laryngoscope after the mapping.
4. Marginal Zone/Pyriform Sinus– These are lateral lesions and usually do not obscure the airway. Very large or pedunculated lesions may cause ball valve type obstruction of the airway. In such situation, direct laryngoscopy with removal of the part of the tumour which is overlying the cords is attempted to secure the airway. Intubation again may lead to dislodgement of tumour in the lower airway causing airway emergency.

Apnoea technique with high flow oxygen through nasal prongs– After pre-oxygenation and induction with Propofol and Succinylcholine; direct laryngoscopy was performed with Kleinssaucers direct laryngoscope to map the mucosal extent of disease and to obtain biopsy. Average time taken for each procedure was 150 seconds with a range of 75 seconds to 300 seconds.

Microlaryngoscopy with or without LASER- suspension laryngoscopy done using direct laryngoscope and microscope at 400 mm focal length. Suspension laryngoscopy with microscope adjustment with or without LASER takes few minutes especially in a post graduate teaching institute, keeping residents training in consideration. Hence all Micro-laryngoscopic procedures were undertaken using 5 to 5.5 size microlaryngoscopy tube. In a few cases where the lesion was extending up to post commissure or inter-arytenoid region, microlaryngoscopy was initiated without securing the airway; with intermittent endotracheal intubation through the suspension laryngoscope which was kept in situ.

Evaluation under Anaesthesia was performed like DL Scopy, and usually the two were combined to assess the lower extent of disease.

CONCLUSIONS

TIVA is safe and provides excellent view of the airway. Patient turn-over in high volume centres is very high & hence cost effective. However, following points should be kept in mind-

1. Preoperative assessment of airway by the evaluating surgeon especially in post cancer directed treatment cases should be done.
2. Pre-procedure counseling of patient and attendants about chance of airway emergency and tracheostomy if deemed necessary, should be done.
3. Fibre optic flexible laryngoscopy along with difficult intubation cart needs to be kept standby in the operating room.
4. Microlaryngoscopy & biopsies and definitive treatment requires longer duration and hence prior or intermittent endotracheal intubation is required.