Effect Of Supraglottic Airway Devices On The Tempromandibular Joint function Following Prolonged General Anesthesia

Supraglottic airway devices (SADs) are used for securing the airway in over 50% of general anesthetics; They are used for both spontaneously & ventilated patients; They also used as conduits to aid endotracheal intubation when both positive mechanical ventilation ( PMV) & tradional endotracheal intubation( ETT) have failed

All (SADs) consist of a tube that connected to a breathing circuit or a breathing bag which is attached to a hypopharengeal device that seals air flow to the glottis

There are many types of SADs including I-Gel, intubating laryngeal mask airway (LMA), LMA CTrash and LMA proseal Although considered relatively safe devices; and have many advantages as they are less invasive than EET, less incidence of bronchospasm, don't often require muscle relaxation or neck mobility

There are several potential complications & disadvantages ; Include temporomandibular joint (TMJ) dysfunction, increases the risk of aspiration, more gas leak &pollution, less safe in prone postion & deeper anaethesia is required

This study will investigate (TMJ) dysfunction following the use of a (SAD) during general anesthesia, as There are a number of insertion maneuvers described for (SADs) [2] such as a jaw thrust may result in temporomandibular joint (TMJ) dysfunction by anteriorly displacing the mandible . In addition, other factors such as degree of muscle relaxation leading to hypotonicity of jaw muscles and passive mouth opening. In addition, for the duration of the operation the mouth is kept slightly open by a breathing tube may result in (TMJ) dislocation.

The inter-incisor distance will be measured using a Therabite â ruler (ATOS Medical, Nottingham, UK). This has a scale from 0 to 70 mm with 1-mm markings. The accuracy of this type of ruler is1.0 mm. The Therabite ruler was chosen as it routinely used by the investigators for (TMJ) assessment in the maxillofacial clinic.

Inclusion The study will include 60 adult patients (>18 years old) with ASA physical status class I and class II scheduled for elective surgery under general anesthesia where SADs ara planned to be used as airway devices

Exclusion Criteria:

1. Patient refusal
2. limited mouth opening(<2 fingers)
3. Facial &upper airway trauma
4. Patients with dentures or who were edentulous (as accurate objective measurements would be difficult to determine)
5. Head and neck surgery (as surgery may influence TMJ function)
6. GITsurgery (as SAD doesn't completely protect air way against aspiration )
7. Pt with preexisting tempromadibular joint dysfunction
8. Duration of anaethesia less than 1 h or more than 4hs-