 Abstract | | |
Severe restriction of airway volume in the orofacial region, caused by temporomandibular joint (TMJ) ankylosis, may lead to obstructive sleep apnea (OSA). If the TMJ ankylosis is progressive, rarely, the caregivers may fail to notice the problem. Such patients may have only symptoms of snoring, daytime sleepiness, fatigue, inability to concentrate, and irritability. At times, emergency tracheostomy may be needed to increase the oxygen supply. Distraction osteogenesis (DO) is a less invasive surgical technique in the management of such OSA by correcting the reduced airway space. In DO, the angulation of the distractors and the pace of activation determine the success of the neo-generation of segments of bone. The formation of a well-corticated mandibular canal (MC) in the newly generated bone is an evidence of the success of the procedure. Such bilateral formation of the MC is not reported from this part of the world. We report a case of a 4-year-old boy who was struggling with OSA due to TMJ ankylosis. He was successfully treated by bilateral mandibular DO. The formation and cortication of the MC is discussed with emphasis on the neural regeneration.
Keywords: Bifocal mandibular distraction, distraction osteogenesis, mandible reconstruction, obstructive sleep apnea
How to cite this article:
Balaji S M, Balaji P. Tracheostomy and mandibular distraction in acute sleep apnea. Indian J Dent Res 2019;30:625-9 |
| Introduction | |  |
Complaints of micrognathia and retrognathism of the lower jaw in a growing child are a red flag for obstructive sleep apnea (OSA). OSA is reported to be a disorder of the upper airway collapse, more frequent during sleep. This leads to oxygen desaturation, which further causes disrupted sleep pattern. The affected child and the caregivers may present with snoring, witnessed apneas, daytime somnolence (excessive sleepiness), fatigue, behavioral, cognitive, and growth impairment. At times, emergency tracheostomy may be needed to increase the oxygen supply. The procedure may be life-saving, as often a young child may suffer from laborious breathing due to decreased oxygen in the system.
To correct the functional and anatomical anomaly, an increase in the airway space is needed. This would be rationale of the surgical treatment. This treatment modality increases the airway volume in three dimensions. Such a goal is easily achieved by distraction osteogenesis (DO). This increase in airway is the most effective treatment of OSA. In children, the rate of relapse is higher and often unfavorable, as the growth centers does not respond in spite of its newer position. The presence of the temporomandibular joint (TMJ) pathologies such as ankylosis complicates the issue.
DO is reported to be a minimal invasive surgical technique that facilitates the native jaw bone to expand to its desired/planned dimension and is a successful treatment modality in the management of OSA. The procedure also eliminates the need for bone grafting, less surgical dissection, and high degree relapse rates that are often associated with jaw advancement surgeries.[1],[2],[3] In this procedure, it is noted that the hard and soft tissues grow together. The effect of this DO on the inferior alveolar nerve (IAN) is the subject of many studies.
The few clinical reports and animal studies involving rat, dogs, and rabbits indicate that in bifocal DO (BDO), the present results indicate that the IAN after BDO can fully recover, and later the peripheral tissue resumes function.[4],[5],[6] Although the functional aspect of the IAN after BDO or DO has been a subject of several studies, the effect of the same on the mandibular canal (MC) has been not adequately reported. The aim of this article is to report a case of proper development of the MC in the immediate consolidation phase after BDO in a very young patient.
| Case Report | | |
A 4-year-old boy reported to our hospital with chief complaint of small lower jaw and progressive inability to fully open the mouth. Recently, the parents identified that their child was not able to open his mouth fully like his peers, was much lethargic, and tend to fall asleep often. On medical consultation, he was referred to the author for opinion and management.
History revealed that the boy's parent had no history of consanguinity. The boy was the first child and only child to his parents. There was no significant pregnancy-related history. The regular ultrasonography revealed no abnormality. The boy had normal delivery process and the milestones were normal. There was no significant medical history or abnormal illness or systemic disease. Further history revealed that the boy had difficulty in opening his mouth and swallowing, and heavy snoring was observed. There was no history of trauma related to the facial skeleton. The initial clinical examination revealed a hypoplastic mandible with chin receded and class II dental relationship. Mouth opening was minimal, and there were no TMJ movements palpable. The oral cavity appeared to be small leading to the diagnosis of micrognathia. Subsequently, the imaging tests were performed [Figure 1]. The three-dimensional computed tomography revealed that the patient had hypoplastic mandible with bilateral TMJ ankylosis, and a developing, possible bifid condyles. It was a stage 2 ankylosis, where the extension of the lesion had involved the sigmoid notch (Topazian's). It was a Type 1 classification of ankylosis where the joint is covered by fibrous adhesions (Sawhney, 1986) limiting the movement. | Figure 1: (a) Pre-operative Orthopantomogram, (b-d) 3DCT scan showing hypoplastic mandible with bilateral TMJ ankylosis, (e-g) Pre-operative clinical photos showing retruded chin and restricted mouth opening with Angle's Class II malocclusion
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On intraoral examination, dentition was present in both the jaws. The tongue space was reduced and the airspace was reduced due to micrognathia. No evidence of abnormality in the brain and other intracranial structures was found. No related records were available to identify the cause of TMJ ankylosis or micrognathia or its association. Diagnostic sleep apnea study indicated a poor compromise in oxygenation during sleep and reduced continuous positive airway pressure with intubation. In the course of the consultations, opinion, and other studies, the patient developed a dire need for an emergency tracheostomy, as the oxygen saturation was progressively decreasing below the critical point, such that he develops signs of cyanosis often, when distressed. This was a critical sign, as the child often exhibited such signs, became progressively lethargic, and at times, nonresponsive to verbal commands. In this evolving, unexpected situation, an emergency tracheostomy was carried out to ensure proper oxygenation.
| Treatment Planning | | |
The goal of the surgery was to increase the airway volume and increase the oxygen saturation. The TMJ ankylosis posed an additional challenge. As it was a fibrous covering, release of the same and continuous exercise would facilitate the normal TMJ movements. As TMJ becomes mobile, the growth center would start functioning. To increase the airspace, the BDO was chosen as an appropriate method. It was intended to widen the mandible using a bifocal horizontal mandibular ramus distractor. The distraction movement and vector placement were planned in such a way that the desired growth could be achieved at the end of the activation period.
| Surgery | | |
Standard general anesthesia preparation and other precautions were undertaken. Standard tracheostomy was done, and further, General anesthesia (GA) gases were administered for further surgical procedure. To reach the TMJ to remove the fibrous adhesions, a preauricular incision of modified question mark pattern (of Al-Kayat and Bramley) was used. After adequate direct visualization, all the adhesions were removed bilaterally. The movement of TMJ was checked and the incision was closed in layers. The evolving bifid condyle was left undisturbed.
The intraoral surgical site was prepared using povidone-iodine disinfectant. Intraorally, buccal vestibular incisions were placed approximately 5 mm below the attached gingiva on either sides of the mandible. The mucoperiosteal flap was raised, and as per the presurgical planning, an osteotomy cut was placed through the outer cortex of the mandibular body such that it carefully avoided the tooth buds. Intraoral horizontal ramus distractors (KLS Martin, Germany) were used on both sides, and bur holes were drilled for the adaptation of the distractor plates [Figure 2]. Care was taken not to injure the IAN path and all developing tooth buds. After placement of the distractors, the function, position, and occlusion were checked. Once the position and movements of the distractors were confirmed, the screws were fixed after which the lingual cortex was split using an osteotome. Similarly, the opposite side was also split. Once again, a thorough final checkup of the function of both the internal distractors was performed, and the intraoral incisions were sutured. Standard antibiotics and nonsteroidal anti-inflammatory drugs were given as per the child's body weight for 5 days. | Figure 2: (a-d) Intra-operative view showing osteotomy cuts placed in the mandibular body bilaterally followed by bilateral mandibular body distractor fixation with the activating arm exiting extra-orally through the mouth
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After fifth day, the BDO was activated to achieve about 25 mm of the mandibular length. Initially, 1 turn of 0.5 mm distraction (0.5 mm/day) was performed until 5 mm was achieved followed by 1 turn of 1 mm distraction (1 mm/day), and finally, again, 1 turn of 0.5 mm/day distraction regimen was performed. Thus, completing 25 mm, sutures and tracheostomy tube were removed. The BDO were left in situ till the completion of the consolidation (mineralization) period. After a period of 2.5 months, the BDO was removed without any complications, and the desired results were achieved [Figure 3] and [Figure 4]. | Figure 3: (a) Post –operative OPG at the end of one week following distraction osteogenesis, (b) Post-distraction OPG taken after a period of 2.5 months revealed satisfactory bone formation with completely formed inferior alveolar canal
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 | Figure 4: (a-c) Post-distraction 3DCT scan taken after a period of 2.5 months revealed satisfactory bone formation
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The patient was followed for 6 months. The orthopantomogram revealed the well-developed bone in the distracted site along with an excellent MC. The innervations and nerve supply to the entire mandible were normal [Figure 5]. | Figure 5: (a) OPG taken after distraction removal showing complete bone formation and inferior alveolar canal with well regenerated inferior alveolar nerve, (b-d) Post-operative 3DCT scan showing fully formed mandibular body. (e-g) Postoperative clinical photographs with improved function and esthetics
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| Discussion | | |
TMJ ankylosis is a chronic condition, which when occurs in children can affect the growth of the entire mandible and also has a bearing on the development of other associated oral structures. In the present case, there is no obvious clinical or other evidence of trauma, infection, or known predisposing factors to TMJ ankylosis.[1] In spite of normal delivery and careful child rearing, in the present case, the parents noted the progressive inability of the child to open his mouth fully. Around the time of presenting to medical help, the child was noted to be lethargic and had a disturbed sleep pattern. The alert clinician identified the symptoms of OSA, identified the need for immediate tracheostomy, arranged it to be performed, and has referred to the author for the management. This emergency maneuver proved to be critical as it underlined the acute need for increasing the airway space in the child. Although it was a “stop-gap” temporary arrangement, it highlighted the kind of physical stress that this reduced airspace placed on the child. Resolution of the sleep apnea with tracheostomy is a routine clinical surgical procedure, to facilitate airway support in case of acute emergencies, such as in the present case report.[1] With the temporary resolution of the problem, the child sleep pattern, oxygen saturation, and attention span reverted to normalcy. Hence, in a bid to provide the child and parents with a permanent solution, an increase in the airway space is the only solution.
Usage of BDO as a treatment modality to increase the airway space volume, in patients with TMJ ankylosis, especially in children has been previously reported.[1],[2],[3] Based on the literature and past experience, BDO was chosen as the primary treatment modality for this patient too. Removal of the fibrous adhesion may have also contributed to the normal functioning of the TMJ. Although modified temporalis anchorage would be most advised, considering the age and the need, the present design was chosen.[7] As patient's oxygen saturation levels, at times, went below the critical limit, the correction was planned along with the emergency tracheostomy procedure. In addition, for the possibly developing bifid condyle, no significant treatment was advised nor done.[8]
Assessment of IAN development and innervations with DO have been a subject of clinical research. Most of the research on this subject was performed on animals – rats, dogs, and rabbits. Various modalities such as electrophysiological, electromyographical, and histological studies have been carried out to assess the short- and long-term effects of DO on IAN innervations. It was observed from the studies that DO at a rapid phase creates substantial evidence of trauma to nerves that reflects as a compromise in the IAN innervations. However, at a slow pace of DO, the nerve is stimulated to extend and the nerve body extension do occur, with fewer, reversible changes.[4],[5],[6],[9],[10]
It has reported that during the process of DO in animals, the IAN may be damaged subsequent to direct injuries as well as that to a distraction strain. IAN in animals is housed in the narrow submandibular nerve tube, which is similar to the MC. Mandible osteotomy, distractor placement, and progressive movement of the bones can cause injuries. This can be avoided by being extremely careful during DO placement.[4],[5],[6],[9],[10],[11],[12] The indirect trauma is from the strain of BDO process. Studies on goat and rabbits indicate that there exists a physiological border, till which the nerve takes up the strain of DO during which there is an effect on the synthesis and proliferation of nerve cells. Beyond the critical point the effect of the strain causes neural degeneration. Slow DO causes mild degeneration of few unmyelinated and no degeneration of the myelinated fibers.[10]
It is also reported that besides the DO pace, the angle also plays an important role in development of distraction stress development. The angle between IAN and the horizontal axis of mandible decreases as DO takes place. As the mandible moves forward, the IAN between the mental foramen and the first deciduous molar remains straight while the horizontal axis tends to be reduced, creating a more lateral force, possibly causing more neurodegeneration. In the present case, it was ensured that such an unfavorable axis change was not made. But the stimulus is sufficient to encourage the Schwann cells to guide nerve regeneration.[10]
Regeneration of the IAN has been widely studied while the MC has not been studied. There is only one case report that suggests the formation of the MC in a free bone graft patient after removal of fibro-osseous lesion.[12] The radiographic density of the MC is variable. A strong radiopaque MC outline is a reflection of the canal's cortication. As a result, in few young patients, the MC is not well-visualized. Carter had earlier reported that radiologically invisible IAN canal may occur because the IAN bundles are not always surrounded by an ossified canal.[12] In the present case, even at the consolidation phase, the MC formation was evident and at the end of the 6 months, normal canaliculization of the MC was observed. This is an interesting finding as the integrity and patency of the MC is a reflection of the proper formation of the mandible for proper form and function. Coupled with the fact that there is no abnormal loss of sensation, pain felt along the region supplied by the IAN on both sides, the formation of MC is a proof of complete normal formation of parts of nerve as well as the normal remodeling of the mandibular bone due to BDO.
| Conclusion | | |
In TMJ ankylosis, the growth centers are affected, possibly affecting the coordinated growth of the orofacial structures. Such deviated formations can decrease the airway space volume. Such a change can pose an immediate threat to life. Institution of emergency tracheostomy would help the surgeon to mitigate the problem temporarily while procedures such as distractions are planned. Even in such cases, formation of normal bone in shortest possible time – in quality and quantity – is always challenging. In the present case, at a short time period, the formation of MC indicates the completeness of the formation of neo-bone generation in the mandible when DO is applied. There has been only one case report of the formation of MC in free bone graft. The phenomenon still remains inadequately studied. Understanding the MC formation in the newly formed segment of bones will help refine the technique of DO in orofacial applications.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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Correspondence Address:
Dr. S M Balaji
Balaji Dental and Craniofacial Hospital, 30, KB Dasan Road, Teynampet, Chennai - 600 018, Tamil Nadu
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ijdr.IJDR_626_19
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5] |
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