Does submental intubation technique show an edge over percutaneous tracheostomy? A prospective study in complex oromaxillofacial surgery
S Deepak, S Dheer
complex oromaxillofacial fractures., percutaneous tracheostomypct, submental intubationsmi
S Deepak, S Dheer. Does submental intubation technique show an edge over percutaneous tracheostomy? A prospective study in complex oromaxillofacial surgery. The Internet Journal of Anesthesiology. 2009 Volume 25 Number 1.
Complex oromaxillofacial injuries involving skeleton framework can compromise airway which is part of the normal contour of the facial bones. In basal skull fracture, when maxillomandibular fixation forms part of surgical treatment, an alternative approach needs to be implied such that the inserted airway device not only avoids the nasal route but also does not obstruct the oral surgical field. Under such circumstances, the choice for securing airway are either percutaneous tracheostomy or submental intubation . This study evaluates the basis of choosing either option in complex oromaxillofacial fracture reduction surgery on the pretext of different factors.
Material and Methods
This prospective study assessed 25 patients with ASA (American Society of Anesthesia) physical status 1 and 2 who sustained maxillofacial fractures from August 2008 to December 2009 scheduled for open reduction and fixation under general anesthesia. The patients were assigned in two groups: submental intubation (SMI) group and percutaneous tracheostomy (PCT) group on the basis of preoperative assessment of interincisor gap. A gap of 4 cm and above allowed laryngoscope blade into mouth for submental intubation. All patients with less than 3 cm underwent percutaneous tracheostomy.
Patients with head injury, cervical spine injury, thoracic and abdominal trauma and defective coagulation profile were excluded from the study. Basic monitoring during general anesthesia included heart rate, electrocardiogram, non invasive blood pressure, arterial O2 saturation and end tidal CO2.
Both the procedures were performed in operation theatre settings and time taken from skin incision to establishing connection of circuit, time for extubation(SMI group)/decannulation(PCT group) and length of stay in intensive care unit in post operative period were analysed statistically implying unpaired t test. P value < 0.05 were considered statistically significant. Submental intubation(SMI) was done after inducing with intravenous propofol, fentanyl and vecuronium as per their body weight and maintained with inhalational isoflurane in O2. Percutaneous tracheostomy was performed without muscle relaxant.
Procedure steps for submental intubation: Trachea was intubated with cuffed oral wire reinforced flexometallic(spiralbind) endotracheal tube of appropriate size. A throat pack was inserted. The submandibular space was draped. A 2 cm long longitudinal skin incision was given with right hand approximately 1.5 cm adjoining lower mandibular margin in the median region of submental area.
A blunt dissection was carried out with a curved dissecting forceps between the muscular layers of mylohyoid to create a tunnel into the floor of mouth near the lingual mandibular margin. This was aided by placing two fingers of other hand at the floor of mouth pushing aside tongue and feeling the correct direction of the curved dissecting forceps. The forceps was opened to widen the tunnel. Hemostatis was maintained. The cuff of the endotracheal tube was deflated and pilot balloon with its valve was grasped with dissecting forceps and negotiated out first through the tunnel followed by proximal end of the flexometallic tube after disconnecting from the ventilator and removing the connector. The ventilator connection was re-established subsequently(figure 1-4). The flexometallic endotracheal tube secured at skin in the submental region with 3.0 silk. At the time of extubation the endotracheal tube was retrieved through submental incision and skin approximated with subcuticular stitch.
Procedure steps for percutaneous tracheostomy (Grigg’s technique): Optimal positioning with the head extended and placing a roll on the back between the two shoulder blades. After skin preparation and surgical draping, a horizontal 2.0 cm long skin incision in midline at the level of second tracheal ring and dissection carried out. The trachea was identified as the needle with saline filed syringe pierced the space between second and third tracheal ring aspirated air. Guidewire was passed through a side channel in the needle which was subsequently withdrawn. Serial dilators were passed over the guide wire to dilate the track. Finally Griggs forceps introduced over the guidewire to widen the track formed in the anterior wall of trachea. The tracheostomy tube placed through the track and correct position confirmed with bilateral air entry in lungs and persistent square waveform on end tidal CO2 .
After completion of surgery, all patients were shifted to recovery and later to intensive care unit in postoperative period. Occlusion was obtained for postoperative period with elastic rubber which was removed and patient subsequently extubated/decannulated in intensive care unit.
Submental intubation was carried out in 15 patients and percutaneous tracheostomy in 10 patients undergoing fixation of oromaxillofacial fractures(table 1) . Demographics of these patients is shown in table 2. The success rate achieved in the two groups in first and second attempt for inserting endotracheal tube in SMI group and tracheostomy tube in PCT group, the average total duration of the procedure from skin incision to establishment of closed airway circuit, the time taken for extubation/decannulation in both groups and the length of stay for each group in intensive care unit are depicted in table 3. Procedural and post procedural complications are enumerated in table 4.
ORIF- open reduction internal fixation, Md- mandible, IMF-Intermaxillary fixation,O- mouth occlusion,NOE- nasal,orbital,ethmoid, POD- post operative day, b/l- bilateral, R- right, L- left, b/o- because of, AE- airway edema, SMI- submental intubation, PCT-percutaneous tracheostomy
With the advent of dynamic compression plates and mini plates maxillofacial surgery is being accomplished with proficiency. Airway management in these complex fracture reduction surgery has always been challenging. Nasal route of securing tracheal intubation in patients with fracture involving base of skull and Lefort can possibly misdirect the tube into cranium leading to brain damage. [1,2] Therefore this route of intubation is best avoided. Surgical procedure of maxillary fixation preclude conventional oral route for intubation.[3.4] Under such circumstances, percutaneous or surgical tracheostomy provides opportunity to secure airway but associated complications with this technique like hemorrhage, subcutaneous emphysema, respiratory infection, difficulty in decannulation, tracheostomal stenosis make it necessary to explore other options. Submental intubation is safe, easy to perform, less invasive with fewer complications which can be easily managed and overcome. A basic knowledge of neck anatomy would facilitate blunt dissection and avoid encountering complications from damage to Wharton’s duct and its gland and other vital structures present in floor of mouth. The technique of submental intubation diverts the proximal end of orotracheal intubation through a tunnel from floor of mouth to its exit at submental region without any impediments. During the study only one incidence of detachment of pilot balloon from the inflating tube of the endotracheal tube was recorded while attempting to bring it out through the tunnel. The cuff of this damaged tube was found to have been dislodge into oropharynx during manipulation. This endotracheal tube was therefore abandoned and immediately replaced without losing control of airway. Despite this, shorter procedure time, earlier removal of endotracheal tube, less stay in intensive care unit and less incidence of complications give submental intubation some edge over tracheostomy. The only limitation of this technique being situation requiring prolong(more than 7 days) postoperative mechanical ventilation support or in condylar fractures where postoperative IMF(intramaxillary fixation: mouth closed) is maintained.
In the present study 9 patients in SMI group where extubated at end of surgery without any problems, 3 patients were extubated after 3-4 days due to airway edema and in 3 patients tracheostomy had to be performed to maintain airway because of IMF.
Besides median approach of submental intubation which we followed, other authors have applied lateral approach of submental intubation. The drawback with it being the presence of submandibular gland in the region which can likely get damaged. Martinez-lage describe retromolar intubation where the orotracheal tube is negotiated through a space carved out by semilunar osteotomy.
Green and Moore secured airway first by orotracheal intubation which they removed after separately passing a reinforced tube from submental incision. Later tube exchangers were brought into practice for converting nasal tube into oral. [10,11]
10 patients with limited mouth opening in preoperative assessment guided us to perform tracheostomy. Although this procedure require more skills and expertise in either performing or dealing with complications, it offers greater safety to patient intra and postoperatively particularly when mandibular occlusion continues in intensive care unit. 4(40%) patients in PCT group had occlusion in postoperative period whereas in SMI group it was only 3(20%).
Minor bleeding was encounted in both the groups. Bleeding during SMI is minor and unproblematic while it can be devastating in PCT if thyroid gland or isthmus is breeched or innominate vessel gets damaged if low tracheostomy is attempted. One false passage was created during PCT which was immediately rectified and one patient suffered difficult decannulation due to tracheostoma.
A prosthetic rehabilitation device provided to this patient maintained the airflow after decannulation.
It is prudent to adopt a cautious approach to airway management in oromaxillofacial surgeries. A particular technique cannot be opted for airway management in oromaxillofacial fractures merely on preoperative airway assessment. Definite surgical plan need to be discussed with the operating surgeon than to struggle with complicated airway which can endanger patients life. Many patients can be managed by submental intubation technique which is less time consuming but also safe, easy and convenient method. Percutaneous tracheostomy cannot be overlooked in situation where postoperative IMF(mouth closure) need to be maintained to avoid malalignment. Postoperative IMF is commonly done for condylar fracture of mandible.