In case of refractory<unk><unk>  disease, the endoscopic access is not possible. A combination of external<unk>  and intranasal endoscopy is used to approach the<unk><unk> . This will help to improve the access to<unk><unk> .<unk>  also enhances the visualization in anatomy. The incision is made in the medial aspect of eyebrow above, parallel to hair line. A 4–5 mm diameter hole is drilled into the anterior table of the<unk> . The best location of the trephine is the floor of<unk>  or through brow ridge. If there is possibility of development of osteomyelitis, trephine should be made inferiorly. Precaution is taken not to injure the supraorbital nerve. The pus is cultured and irrigated, and the<unk>  is cleared with a saline or an antibiotic solution. Extra holes are cut in two pieces of french red Robinson rubber catheter or Silastic tubing. The two tubing pieces are inserted through trephine and sutured. An alternative method is the minitrephine system manufactured by Medtronic-Xomed, in which a metal cannula wedged firmly into an accurately shaped hole is used.
Frontal sinus trephination
Trabeculectomy
Iridodonesis
Astragalectomy
Transsphenoidal surgery
Middle ear implant
Mastoidectomy
Head transplant