Effect of Montelukast Therapy in Obstructive Sleep Apnea(OSA) Children

The investigators leading hypotheses are: * Oral therapy with montelukast may lead to improved sleep study findings in children with mild to moderate Obstructive Sleep Apnea Syndrome (OSAS) who require surgical removal of adenoids and tonsils for OSAS. * A significant proportion of the children with OSAS treated with montelukast will show reduced severity of OSAS, and this will remove the need for surgical intervention.