|Year : 2008 | Volume
| Issue : 6 | Page : 861
Molar Intubation for Intra Oral Swellings:Our Experience
Meenoti Potdar1, RD Patel2, LV Dewoolkar3
1 Lecturer, Department of Anaesthesiology, Seth G.S. Medical College and K.E.M.Hospital, Mumbai, India
2 Associate Professor, Department of Anaesthesiology, Seth G.S. Medical College and K.E.M.Hospital, Mumbai, India
3 Professor and Head, Department of Anaesthesiology, Seth G.S. Medical College and K.E.M.Hospital, Mumbai, India
|Date of Acceptance||28-Sep-2008|
|Date of Web Publication||19-Mar-2010|
Department of Anaesthesia, Seth G.S.Medical College, K.E.M.Hospital, Aacharya Donde Marg, Parel, Mumbai-400018
Molar intubation is a technique of laryngoscopy that can be used for anticipated difficult intubation in cases where standard laryngoscopy technique is difficult due to presence of any intraoral mass that anatomically hampers laryngoscopy or that bleeds on touch. This technique is very easy, reliable and rewarding but should be practiced on normal patients for easy application in actual difficult cases.
Keywords: Molar approach, Intubation, Intraoral masses, Difficult laryngoscopy, MaCoy′s blade, Macintosh blade
|How to cite this article:|
Potdar M, Patel R D, Dewoolkar L V. Molar Intubation for Intra Oral Swellings:Our Experience. Indian J Anaesth 2008;52:861
| Introduction|| |
Securing and maintaining a patent airway for intra oral swellings is a great challenge to the anaesthesiologist. Difficult laryngoscopy is encountered more often in these cases as they encroach and physically occupy the oral cavity thus making glottic visualization difficult and thus a difficult maneuvering of the endotracheal intubation. This difficulty is frequently overcome using a molar approach for laryngoscopy with Macintosh or MacCoy's laryngoscopy blade. Left molar approach is more effective in improving the direct glottic view with Macintosh blade and right molar approach is effective with a straight Miller's blade. 
We therefore are documenting a few cases where the molar approach of laryngoscopy and intubation has aided us in visualization of glottis and securing the airway.
| Case # 1|| |
A 25-year-male diagnosed as carcinoma of the tongue was posted for total glossectomy with radical neck dissection. The patient gave H/o swelling on the right lateral border of the tongue that was tender and used to bleed on touch. Patient had history of chronic ghutka consumption.
On local examination of the oral cavity there was an ulcerative lesion on the right lateral border of the tongue with surrounding induration crossing the midline of the tongue. There was bleeding from the lesion on touch. Movements and protrusion of the tongue were restricted. CT scan revealed involvement of the base of the tongue, floor of the mouth and the submandibular lymph nodes. Indirect laryngoscopy was not possible. Mouth opening and the neck movements were adequate.
General anaesthesia was induced and laryngoscopy was done with No. 3 Macintosh blade through the left molar approach to visualize glottis.
| Case 2|| |
A 58-year-old male with right sided tonsillar pillar mass crossing the midline was scheduled for tonsillar resection. Patient was a chronic tobacco chewer. The provisional diagnosis was tonsillar carcinoma.
On local examination swelling was on the right tonsillar pillar crossing the midline. Uvula was spared. Movement of the tongue was normal. The airway distances and neck movements were adequate. General anaesthesia was induced and tracheal intubation was facilitated with laryngoscopy with McCoy's blade #4 by left molar approach.
| Case #3|| |
A 42-year-male with recurrent right sided Ca maxilla presented with right sided swelling involving the right lip and the angle of the mouth was scheduled for extended maxillectomy. On local examination there was growth at the angle of the mouth that bled on touch. Mouth opening was restricted to one and a half finger. Indirect laryngoscopy was not possible. Protrusion of the tongue was not possible. Neck movements were adequate and normal. He was operated case of keratinizing squamous cell carcinoma.
General anaesthesia was induced and tracheal intubation was facilitated with Macintosh blade # 3 by left molar approach aided with intubating bougie.
| Case #4|| |
A 17-year-male mentally retarded diagnosed to have bilateral parapharyngeal, submandibular and mediastinal abscesses, left more than right was posted for incision and drainage. Patient did not allow the procedure under local anaesthesia hence required sedation for the same. On local examination bilateral swelling was seen in the oral cavity with parapharyngeal, submandibular and mental fullness with pus discharge on left side. Mouth opening was adequate. Mallampatti classification was Grade I. Indirect laryngoscopy was not possible. Neck movements were adequate.
On CT chest, patient had bilateral parapharyngeal, submandibular abscess extending in the superior and anterior mediastinum. Trachea and upper airway was visualized and was adequate. Patient was pre-oxygenated with 100% oxygen. Patient was nebulised with 4% lidocaine and lidocaine 4% viscous gargles were given. Awake laryngoscopy was done by right molar approach with #3 Macintosh blade to facilitate endotracheal intubation. Patient was maintained on oxygen, nitrous oxide with ketamine infusion.
[Figure 2] and [Figure 3]
| Case # 5 & # 6|| |
A 22-year-old male was posted for excision of plunging ranula. Patient gave a history of swelling in the floor of the mouth gradually increasing in size.
Case # 6 was a 26yr old male posted for excision of a plunging ranula and had similar findings as case # 5.
On local examination swelling was seen in the floor of the mouth that extended externally to the submandibular and submental region. Ballotment and transillumination was positive. Swelling was more on the right side than on the left side. CT scan revealed involvement below the mylohyoid muscle. Mouth opening was adequate but Mallampatti classification was Grade IV. Neck movements were adequate. Indirect laryngoscopy was possible and larynx could be visualised.
General anaesthesia was induced and tracheal intubation was facilitated with laryngoscopy by left molar approach with #3 Macintosh blade in both cases.
| Case # 7|| |
A 35-year-old male patient presented with nasal obstruction and mass coming out through the oropharynx. The patient could pull out the mass digitally anteriorly in case of severe difficulty in breathing. Indirect laryngoscopy couldnot be done due to the size of the mass. CT scan revealed that the mass was extending from the nasal cavity into the oropharynx just in short of the epiglottis. Mouth opening was adequate and Mallampatti classification was grade I. Neck movements were adequate.
General anaesthesia was induced and tracheal intubation was facilitated with laryngoscopy by right molar approach with #3 Macintosh blade.
In the preanaesthetic evaluation all patients did not have any other significant medical or surgical illness in the past. Routine laboratory investigations were within normal limits
All patients were premedicated with glycopyrrolate 4µg.kg -1 IM half an hour prior to procedure. Patient was pre-oxygenated with 100% oxygen. Anaesthesia was induced with propofol 2-3 mg.kg -1 IV. After ensuring adequate ventilation of the lungs, tracheal intubation was facilitated with suxamethonium 2mg.kg -1 IV by molar approach of laryngoscopy with appropriate size blade. Placement of the endotracheal tube was confirmed by auscultatory method. Muscle relaxation was maintained with vecuronium bromide 0.1 mg.kg -1 IV. Sedation and analgesia was maintained with midazolam 0.05mg.kg -1 and pentazocine 0.5mg.kg -1 IV respectively. The intraoperative period was uneventful.
After surgery all patients were reversed for neuromuscular blockade with neostigmine 0.05mg.kg -1 and glycopyrrolate 8µg.kg -1 IV. The tracheal tube was removed after complete reversal of neuromuscular blockade and adequate spontaneous respiration.
| Technique of molar approach of laryngoscopy and intubation.|| |
A Macintosh No3 or No4 blade depending on the patient, was passed from the right or the left corner of the mouth depending on the site and side of the intra oral lesion. It is inserted along the groove between the tongue and the tonsil at the point prior to the molar teeth using an anterior and medial pressure pushing the tongue towards the midline and maintaining in that position at all times. Then the tip of the blade is directed postero-medially under the base of the tongue until the epiglottis and rima glottides are seen ,  An endotracheal tube with stillete was then introduced and advanced from the corner of the mouth from the point behind the molar teeth. When the tip of the endotracheal tube appears in the field of the laryngoscope, it is advanced through the glottic opening into the trachea under the direct vision. As there is restricted space it is helpful if an assistant retracts the corner of the mouthduring introduction of the endotracheal tube  .
| Discussion|| |
The cause of difficult laryngoscopy and visualization of the glottis may be multifactorial. It may be due to obvious obstacles including maxillary structures like prominent incisors, increased volume of tongue remaining anterior to the blade due to infra lingual swellings or intraoral swellings. In laryngoscopy with molar approach the laryngoscope blade is inserted above the molars. This approach reduces the distance from the patients teeth to the larynx and thus prevents intrusion of intraoral, maxillary structures into the line of vision. This approach also avoids a large volume of the tongue remaining anterior to the blade as compared to the midline approach  .
We had planned a molar approach of intubation in all our cases due to presence of intraoral swellings that would either hamper the Macintosh technique of laryngoscopy or the swelling would obscure our line of vision post laryngoscopy or would make introduction of the endotracheal tube difficult. We preferred the Macintosh blade as we are not comfortable and experienced enough using the Miller blade in our institute. The visualization of the glottis is excellent with the Miller blade but the maneuvering and the introduction of the endotracheal tube is very difficult and requires a good amount of practice. A paraglossal technique with Miller blade can only be used successfully from the right side of the mouth. Attempts to use it from the left are not effective as the tongue bulges over the blade and obscures the view of glottis  .
In our case no 1, the standard laryngoscopy technique was not preferred as the lesion was on the right lateral border of the tongue and bled on touch hence we preferred the left molar approach of intubation. In case no.2, the patient had a right tonsillar pillar mass crossing the midline that would obscure the vision by standard laryngoscopy technique hence we opted for left molar approach of intubation. In case no. 3, the patient had right sided carcinoma of maxilla with involvement of the lip and angle of the mouth, so we opted for left sided molar intubation. Case no. 4 had left sided parapharyngeal abscess that was big and had ruptured hence right sided laryngoscopy was preferred. Case no 5 and 6 had plunging ranula in the floor of the mouth that extended externally to the submental and submandibular region. Swelling on the right side was more than the left in both the cases. Hence left sided molar approach was opted  . Nasal intubation was not preferred in case No 5, as the anterior nares were very small and case No. 6 had deviated nasal septum. Fibreoptic intubation would be an option to the above cases but non availability of the scope was a constraint. In case No 7 fibreoptic intubation would be ideal but due to nasal mass extending upto the oropharynx, fibreoptic intubation was not possible as there was no space to put in the flexible scope and hence a left molar approach of intubation was preferred  . We had our ENT surgeons ready for tracheostomy in case we were unable to secure the airway.
The similar technique of molar approach also known as the paraglossal technique with straight blade has also been described by others.
Bonfils et al used the term retromolar for this same variation of the paraglossal technique  . Others like Arai et al  and Crinquette et al  advocated keeping the blade above the molar and turning the head to the left.
Several methods of optimizing the view with this technique have been advocated ,,,,,,, . One amongst them is external laryngeal pressure which improves the view of the larynx ,, .
Various studies have concluded that left molar approach improves the laryngeal view in patient with difficult laryngoscopy ,, . Akidmen recommended in troduction of an infant sized straight blade from the left angle of the mouth at the point posterior to the molar teeth for adult patients with difficult laryngoscopy  .
Russell et al advocated the use of two laryngoscopes for difficult intubation  .
The limitations of this technique are that during a right molar approach there is not enough space to introduce the endotracheal tube due to the cheek and hence an assistant is necessary to pull the right side of the mouth to make room to manipulate the endotracheal tube  .
In the left sided molar approach the tongue bulges over the blade which may obscure the view of the glottis that deviates the line of view of laryngoscopy laterally from the midline making it difficult to align the tip of the endotracheal tube with the aperture of the glottis. 
Thus to conclude to increase the efficacy of molar approach anaesthesiologist should practice the technique on patients with normal airway. In cases of anticipated difficult airway due to intraoral masses, macroglossia that can obscure the field of vision or where the Macintosh technique of laryngoscopy can be traumatic or can cause bleeding, molar approach of laryngoscopy and intubation is a better advocated technique.
| References|| |
|1.||Henderson JJ. The use of paraglossal straight blade laryngoscopy in difficult tracheal intubation. Anaesthesia 1997: 52: 552-60. |
|2.||Yamamato K, Tsubokawa T, Shigeo Ohmura, Hironori Itoh, Tsutomu Kobayashi. Left molar approach improves the laryngeal view in patients with difficult laryngoscopy. Anesthesiology 2000; 92: 70-4. |
|3.||Bonfils P. Difficult intubation in Pierre-Robin children, a new method: the retromolar route. Anaesthetist 1983; 32: 363-7. |
|4.||Arai T, Nagaro T, Nitta K. Management of difficult endotracheal intubation; advantages of the Miller blade and a facilitated nasotracheal intubation with a fibreoptic bronchoscope. Masui (Japanese Journal of Anaesthesiology) 1987; 36:1112-6. |
|5.||Crinquette V, Vilette B. Solanet C, et al. Appraisal of PCV, a laryngoscope for difficult endotracheal intubation. Annales Francaises D'Anesthesie et de R'eanimation 1991; 10: 589-94. |
|6.||McIntyre JWR. The difficult tracheal intubation. Can J Anaesth 1987; 34: 204-13. |
|7.||Benumof JL. Difficult laryngoscopy: obtaining the best view. Can J Anaesth 1994; 41: 361-5. |
|8.||Knill R L. Difficult laryngoscopy made easy with a 'BURP'. Can J Anaesth 1993; 40: 279-82. |
|9.||Krantz MA, Poulos JG, Chaouki K, Adamck P. The laryngeal lift: a method to facilitate endotracheal intubation. J Clin Anesth 1993; 5: 279-301. |
|10.||Cormack RS, Carli F, Williams KN. Unexpected difficult laryngoscopy. Br J Anaesth 1991 :67:501-2. |
|11.||Carli F, Williams KN, Cormack RS. Difficult laryngoscopy. Br J Anaesth 1992; 68: 117-8. |
|12.||Marks RRD, Hancock R, Charters P. An analysis of laryngoscope blade shape and design: new criteria for laryngoscope evaluation. Can J Anaesth 1993; 40: 262-70. |
|13.||Sharma S, Sehgal R, Kumar R, Sharma K, Agrawal N. The left molar approach, the right molar approach and midline approach for direct laryngoscopy and intubation using Macintosh blade. J Anaesth Clin Pharmacol 2007; 23: 41-46. |
|14.||Raut PS, Patel RD. Comparative study of molar approach of laryngoscopy using Macintosh versus Flexitip blade. The Internet Journal of Anaesthesiology 2007;12 . |
|15.||Akidmen SA: A modified technique for direct laryngoscopy and tracheal intubation. Anesthesiology 1996; 27: 321. |
|16.||Russel SH, Hirsch NP. Simultaneous use of two laryngoscopes. Anaesthesia 1993;48:918. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4]