| MCV ENT UPDATE | |
| Update : January - March 2007 | |
| OSA SURGICAL TECHNIQUE | |
Obstructive sleep apnea often referred to as snoring falls under the group called Sleep Disordered Breathing (SDB) along with primary snoring and upper airway breathing syndrome. However OSA can be differentiated from the latter on the basis of APNEA INDEX (AI). Apnea is defined as cessation of airflow at the nostrils or mouth for at least 10 seconds. AI is defined as number of apneic spells per hour of sleep. An AI of greater than 5 indicates OSA.
According to American Sleep Association, OSA is classified as : Mild - AI-5-20 At our centre a patient reporting with history of loud snoring, excessive daytime sleepiness, and loss of concentration and choking episodes at night is considered as possibly suffering from OSA. A detailed history is taken which includes respiratory and cardiac history, thyroid dysfunction, and drug, alcohol, smoking and social history. Complete Oro-nasal examination of septum, turbinates, base of tongue, tonsils, uvula and palate is done. Flexible nasopharangoscopy on reverse valsalva is performed to find the site and degree of prolapse of tissue at the oropharangeal level. Radiological assessment is done by taking X-ray soft tissue neck and chest X-rays. The patient then undergoes an overnight sleep study at the hospital or in his house itself. The study entails hourly pulse and oxygen saturation measurement, number of apneic spells and ECG. More than 5 apneic spells per hour and fall of spO2<90 during these spells is considered significant.
Patient selection for surgery is done on the basis of polysomnography and clinico -radiological assessment. The surgical protocol adopted involves correction of nasal pathology (SMR+radio frequency SMD of turbinates) if required under LA, Laser UVPP-under GA with nasotracheal intubation is done, Using CO2 laser B/L tonsillectomy is done followed by laser excision of the redundant tissue over soft palate and the uvula. The resultant mucosal flaps of the soft palate are sutured using 3-0 vicryl as are the tonsillar pillars. Radio frequency is applied to several points over the tongue base and soft palate. The nasotracheal tube is left in situ till the next day to avoid airway obstruction due to immediate post op edema and the need for an emergency tracheostomy. Patients with an excessively bulky tongue base requires an additional procedure in the form of Hyoid suspension with genioglossus advancement. Using two horizontal neck incisions in the upper neck the hyoid and symphysis menti are exposed. A rectangular bone window 3cm x1cm is created in the mandible using osteotomies and cutting drill. A Micro Oscillating saw makes this step neater & quicker. The bone window is brought out such that the inner table of window is in line with outer table of mandible, this results in the advancement of posterior attached genioglossus. A s/c plane is created between the mentum and hyoid after an infrahyoid myotomy. The hyoid is pulled upwards and suspended from the mandible using 1-0 prolene. The above procedure should be continued with weight reduction, physical exercise and avoidance of
alcohol
before sleep. Simhasana being a specific yoga technique for genioglossus is also beneficial. Over all long term success rate of these procedures are 70 - 80% with external procedures being more reliable. |
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