Anesth Analg 2006;103:1122-1125
© 2006 International Anesthesia Research Society
doi: 10.1213/01.ane.0000247852.09732.ec
PEDIATRIC ANESTHESIA
An Evaluation of the Retromolar Space for Oral Tracheal Tube Placement for Maxillofacial Surgery in Children
Suman Arora, MD*,
Vidya Rattan, MDS , and
Neerja Bhardwaj, MD*
From the *Department of Anaesthesia and Intensive Care; and Unit of Oral & Maxillofacial Surgery, Oral Health Sciences Center, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India.
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Abstract
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BACKGROUND: The eruption of the first and second permanent molar teeth may influence the size of the retromolar space. In this study we evaluated the adequacy of the retromolar space for retromolar intubation and any effect of eruption of the first and second permanent molar teeth on this space in children.
METHODS: Children 3–15 yr of age, undergoing surgery other than facial surgery were included for evaluation of the retromolar space. After standard oral tracheal intubation, the endotracheal tube was shifted to the retromolar space and the mandible was slowly closed to achieve centric occlusion. At the same time, any increase in airway resistance or decrease in oxygen saturation was noted. In the second part of the study, the feasibility of retromolar intubation in pediatric patients undergoing maxillofacial surgery with intraoperative maxillomandibular fixation was assessed.
RESULTS: There was enough space for endotracheal tube placement in the retromolar region. The eruption of the first and second permanent molar teeth did not affect intubation. It was possible to achieve centric occlusion in 79 of 80 children with the endotracheal tube positioned in the retromolar space. Retromolar intubation was successfully accomplished in six pediatric patients undergoing maxillomandibular fixation and maxillofacial surgery.
CONCLUSION: The retromolar space can be safely used for intubation in children when intraoperative maxillomandibular fixation, and simultaneous access to the nose and oral cavity are needed.
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Introduction
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Airway management during surgery in patients with complex craniomaxillofacial trauma has always been a challenge for anesthesiologists, as the surgeon and the anesthesiologist share the same limited space. Intraoperative assessment of occlusion and maxillomandibular fixation is often required for exact reduction of facial fractures. Conventional oral tracheal intubation does not allow intraoperative assessment of the occlusion and maxillomandibular wiring. Most oral surgical procedures are undertaken with the nasotracheal tube in place. In certain circumstances where access to both the nose and oral cavity is required, the endotracheal tube has to be shifted intraoperatively from the nose to the oral cavity or vice versa. Nasal, when compared with oral intubation is more traumatic, more time consuming, and associated with potential complications such as epistaxis, intracranial intubation, and infection. In certain situations, such as skull base fractures and posttraumatic nasal cerebrospinal fluid leak, nasotracheal intubation is contraindicated. Alternate routes of airway management for these patients are submental intubation (1) and temporary tracheostomy. Both of these alternatives are time consuming, surgically invasive, and are associated with increased morbidity.
The use of the retromolar route (2,3) for intubation can be an acceptable alternative to prevent these problems. With this technique, the endotracheal tube is placed in the retromolar space behind the last erupted teeth. The retromolar space is bounded superiorly by the maxillary tuberosity and the retrotuberosity area, inferiorly by the retromolar trigone area, anteriorly by the last erupted molar teeth, posteriorly by the anterior border of ascending ramus of the mandible, medially by the lateral surfaces of the tuberosity, the last erupted molars and the oral cavity, and laterally by the medial surface of ascending ramus and the buccal vestibule. There is limited literature and no guidelines on the use of the retromolar route for orotracheal intubation for patients requiring simultaneous jaw and nasal surgery. The basic requirement for successful placement of the endotracheal tube in the retromolar region is the presence of adequate space in the retromolar area. The retromolar space may be influenced by the eruption status and the presence of the last teeth. There may be a decrease in the retromolar space after the eruption of the second permanent molar (Figs. 1a and b). The eruption status of the teeth changes with development in children. Deciduous dentition is usually complete by 2.5 yr with the eruption of the deciduous second molar. The first permanent molar erupts at 6 yr, the permanent second molar erupts at 12 yr. Moreover, as the child grows, a larger endotracheal tube size is required for intubation, while the retromolar space tends to decrease with age and eruption of the molar teeth.
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Figure 1. (a) Orthopantomograph of a six-year-old child. Note there is enough retromolar space behind the erupted permanent first molar. (b) Orthopantomograph of a 12-year-old child. Note that retromolar space behind the erupted permanent second molar has decreased when compared with (a).
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The aim of this study was to evaluate the adequacy of the retromolar space for retromolar intubation and the effect of first and second permanent molar teeth eruption on this space in normal children. In addition, in the second part of the study, the feasibility of retromolar intubation was assessed in pediatric patients undergoing maxillofacial surgery.
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METHODS
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The study was approved by our IRB and written informed consent for oral tracheal intubation and the surgical procedure was obtained from parents of all subjects. Eighty patients of either sex, aged 3–15 yr, scheduled to undergo general anesthesia for varying surgical procedures were included in the study. Patients with a history of extraction of teeth, any craniofacial deformity, and intraoral pathology were excluded. The presence of the last erupted molar teeth was noted. Oral tracheal intubation was performed in a standard manner with an appropriately sized endotracheal tube placed after the induction of anesthesia. Once correct placement of the orotracheal tube was confirmed, airway pressure and arterial oxygen saturation (Spo2) were noted. The tube was then repositioned behind the upper last molar in the retromolar space on either side. The maximum intercuspation of teeth was attempted by closing the mandible, and the ability to achieve centric occlusion was determined (Fig. 2). At the same time, any increase in airway resistance or decrease in Spo2 was noted. After this procedure, the endotracheal tube was positioned back to its normal position and secured with adhesive tape and the planned surgery commenced. For the purpose of the analysis, children were grouped into three age groups.
In the second part of this study, the retromolar route was used for tracheal tube placement in six pediatric maxillofacial surgery patients. In these six patients, an appropriately sized flexometallic tracheal tube was used. Intraoperative maxillomandibular fixation was performed in all cases to achieve the objectives of surgery. After completion of the procedure, maxillomandibular fixation was released and the patient was extubated. Any difficulty in achieving maxillomandibular fixation, an increase in airway resistance, a decreased Spo2, and ulcerations in the retromolar area during the postoperative period were noted.
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RESULTS
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Eighty children between the ages of 3–15 yr were examined. In 79 cases, centric occlusion could be satisfactorily achieved with the endotracheal tube positioned in the retromolar space. The distribution of these 79 children, on the basis of age group, gender, the status of last molars, any change in airway resistance, and Spo2 levels, are shown in Table 1. In one 12-year-old male child, the second molar had erupted, and occlusion could not be achieved with the endotracheal tube positioned in the retromolar space. There was no influence of age, sex, and presence of the last teeth on the retromolar space for intubation. There was no increase in airway resistance and decrease in Spo2 with the teeth in centric occlusion.
The demographic and clinical data of the six pediatric patients, in whom the airway was managed with retromolar intubation are shown in Table 2. Of these six patients, four involved craniomaxillofacial trauma and two required orthognathic surgeries. There was no difficulty in maxillomandibular fixation and maintenance of anesthesia in any of the six patients. There were no adverse events or complications seen in any of these patients.
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DISCUSSION
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Martinez-Lage et al. (3) described the retromolar route for intubation in craniofacial and orthognathic surgeries to avoid the complications associated with conventionally used airway management techniques. Retromolar intubation was performed with a wire-reinforced tube in the retromolar trigone after the third molar, whether erupted or unerupted, was extracted. In addition, the bone was removed from the ascending ramus of mandible so as to create enough space for the endotracheal tube to lie below the plane of occlusion. This technique was criticized (4) as it involved destruction of bone for the sole purpose of creating a space for the oral tracheal tube. In addition, it also increased operating time. Gibbons et al. (5) reported a case where retromolar placement of the endotracheal tube was used in complex craniofacial trauma after extracting the nonfunctional third molar. Halsnad et al. (6) also reported a case in which they used the retromolar space for intubation because of a mandibular fracture. A dentist or an oral and maxillofacial surgeon may be the best person to make the decision regarding extraction of the third molar for the sole purpose of creating space for intubation. Dutta et al. (2) observed that in adults the retromolar area had enough space for placement of the endotracheal tube in 42 patients undergoing a variety of maxillofacial procedures. However, there is great variation in the retromolar space when third molars are impacted or fully erupted. There are no published data regarding the use of the retromolar route in the pediatric population. The results of this study suggest that the retromolar route can be safely used in nonsyndromic pediatric patients, as there was no change in airway resistance and Spo2 with the teeth in centric occlusion. An orthopantomograph radiograph (Fig. 1) may be helpful in evaluating the adequacy of the retromolar space for endotracheal tube placement, but it provides only a two-dimensional picture of the space, and it may not be accurate. It was not possible to take radiographs in all study cases for ethical reasons. Placing the index finger in the retromolar space and asking the patient to close slowly on the finger has been recommended to determine the adequacy of the retromolar space (3). This technique may not be possible in children because it requires patient cooperation.
The role of the retromolar space in patients with various craniofacial syndromes such as Pierre Robin syndrome, Treacher Collin syndrome, achondroplasia, and mandibular hypoplasia has not been evaluated. Variation of the retromolar space with various occlusion types and skeletal profiles in the normal population also needs to be further analyzed.
In conclusion, this study confirms that there is adequate space in the retromolar area for endotracheal tube placement in children. This space is not influenced by the eruption of permanent first and second molars. It is possible to achieve centric occlusion with an oral tracheal tube positioned in the retromolar space. Thus, the retromolar route can be used for intubation in nonsyndromic children, when intraoperative maxillomandibular fixation, and simultaneous access to the nose and oral cavity are required.
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Footnotes
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Accepted publication on July 27, 2006.
Author correspondence and reprint requests to Vidya Rattan, MDS, Unit of Oral & Maxillofacial Surgery, Oral Health Sciences Center, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India. Address e-mail to drvidyarattan{at}sancharnet.in.
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REFERENCES
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- Hernandez AF. The submental route for endotracheal intubation–a new technique. J Maxillofac Surg 1986;14:64, 65.
- Dutta A, Kumar V, Saha SS, Khazanchi RK. Retromolar tracheal tube positioning for patients undergoing faciomaxillary surgery. Can J Anaesth 2005;52:341.[Web of Science][Medline]
- Martinez-Lage JL, Eslava JM, Cebrecos AI, Marcos O. Retromolar intubation. J Oral Maxillofac Surg 1998;56:302–5.[Web of Science][Medline]
- Werther JR. Retromolar intubation (discussion). J Oral Maxillofac Surg 1998;56:305, 306.
- Gibbons AJ, Hope DA, Silvester KC. Oral endotracheal intubation in the management of midfacial fractures. Br J Oral Maxillofac Surg 2003;41:259, 260.
- Halsnad SM, Wilkins IA, Adlam DM. Oral endotracheal intubation in the management of midfacial fractures (letter). Br J Oral Maxillofac Surg 2005;43:190, 191.
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Abstract
Introduction
