Assessment of Oropharyngeal Airway Before and After Distraction Osteogenesis in Patients with Obstructive Sleep Apnoea Syndrome – A Clinical Study

Abstract

Background: This study was conducted for the assessment of oropharyngeal airway before and after distraction osteogenesis in patients with obstructive sleep apnoea syndrome.

Materials and methods: Ten patients with mandibular hypoplasia of obstructive sleep apnoea syndrome were included in the study. A detailed case history was recorded. Pre operatively Clinical examination, General systemic examination, physical examination, routine hematological investigations, HbsAG (hepatitis B antigen) testing, ECG (electro cardio gram) evaluation, HIV (human Immunodeficiency Virus) a chest x-ray evaluation were done for all the patients in the study. Preoperatively before starting distraction, photographs and relevant radiographs like OPG, Lateral Cephalogram, Cephalometric Analysis, Overnight Polysomnogram, snoring, Heart Rate, Oxygen saturation, Linear Oropharyngeal airway space, Apnoea and Hypopnoea Index values were calculated. Patient Mock Surgery i.e, preoperative study models – articulation, osteotomy cuts were made. Then Pre-anaesthetic evaluation done. Presurgical antibiotic therapy was done before one day of the surgery, followed by surgery under general anaesthesia. Patients’ guardians were asked to sign in a written informed consent form explaining the procedure and also any complications that may arise as a result of the surgery. Any additional investigations, if required, as per the systemic condition of patient were carried out. Anaesthetist consent and physician consent were taken. Surgery was performed under general anaesthesia in a standardized manner by same group of surgeons. Bilaterally submandibular incision was made to access the posterior body, angle, lateral and medial rami of the mandible, Once the surgery was done the distractors are placed bilaterally extra-orally and suturing done patient given antibiotics and analgesics for a week post operatively patient is advised to take soft and liquid diet for a month. Then the patient was advised to come for follow up in 1,3,6,9,12 months. For all the ten patients in this study a standard 2.5 cm intraoral mandibular distractors were placed, after latency period of 5 days and activation of 1 mm per day for a maximum period of 25 days (length of the distractor is fixed). Thus, 2.5 cm or 25 mm of maximal distraction was achieved. Post operatively clinical, radiographical, polysomnographic, Heart rate, Apnoea and Hypopnoea Index, Oxygen saturation values were evaluated for all the patients in the study. Patients in the present study were recalled in 1 ,3, 6, 9,12 months after distraction osteogenesis to assess and evaluate the clinical, radiographical, polysomnograhic and functional changes post operatively. Preoperative photographs and Pre operative relevant radiographs like, Lateral cephalogram, sleep study was taken for all the patients in the present study. Patients were systematically followed up postoperatively at an interval of 1,3,6,9,12 months for the evaluation of oropharyngeal airway space and airway obstruction, oxygen saturation, apnoea and hypopnoea index, heart rate. As a part of record a printed report including patient data, details of surgery, and pre and post operative photographs were maintained.

Results: In the present study all the 10 patients are with Obstructive Sleep Apnea Syndrome with mandible hypoplasia, all ten patients in the study undergone distraction osteogenesis of the mandible. Clinically and radiographically follow up has done after distraction of the mandible. Clinically and radiographically, there is an increase in the mandible length, air way space which is measured cephalometrically on lateral cephalogram after distraction osteogenesis of the mandible. The results showed an increase in the mandibular length, increase in airway space, increase in oxygen saturation, decrease in snoring events and decrease in the Apnea Hypopnea Index (AHI) statistically.

Conclusion: The study concludes that the Mandibular distraction osteogenesis is an effective treatment in treating the patients with mandibular deformities associated with unilateral or bilateral TMJ ankylosis and also in treating the patients with obstructive sleep apnea syndrome. The results concluded that the Mandibular Distraction Osteogenesis is a successful treatment in treating the upper Airway Management and stated that Mandibular retrognathia may cause upper airway obstruction in the paediatric patient due to tongue collapse and physical obstruction in the hypopharyngeal region. Most commonly, the aetiology of upper airway obstruction is associated with a craniofacial malformation or other anomaly such as Pierre Robin sequence, Treacher Collins syndrome, hemifacial (craniofacial) microsomia, Nager syndrome that include mandibular anteroposterior hypoplasia, or developmental failure of growth of the mandible in utero, these disorders in the individual patient is responsible for the wide range of respiratory compromise that is observed clinically in terms of disordered breathing and inability to maintain appropriate levels of arterial oxygen saturation and concluded that Mandibular distraction osteogenesis (MDO) is a viable option for the paediatric patient with upper airway obstruction due to mandibular deficiency to avoid a tracheostomy or other surgical intervention.