Rescue microlaryngoscopy: a protocol for utilization of four techniques in overcoming challenging exposures in...

To discuss four techniques used to overcome the problem of difficult exposure during operative microlaryngoscopy (microdirect laryngoscopy [MDL]). The protocol uses four techniques in escalating fashion. These techniques are: high-frequency jet ventilation (high-frequency positive pressure ventilation [HFPPV]), using a narrow-bore diagnostic laryngoscope (Holinger) with suspension, using the 30° and 70° telescopes with angled instruments, and using a flexible laryngoscope through a laryngeal mask anesthesia (LMA) device.

From 1996 to 2010, endoscopy photographs from 1840 cases of MDL were reviewed. There were 12 cases used with HFPPV. Ten cases were done with the small-bore Holinger laryngoscope. Two cases were done using telescopes, and one case necessitated the use of a therapeutic flexible laryngoscope through the LMA device. Only one case was aborted because of poor ventilation. These 26 cases are reviewed.

Most microlaryngoscopy procedures (98.5%) were able to be performed with standard operating laryngoscopes using the microscope. Risk factors that contributed to difficulty in exposure included two cases of prior radiation therapy, one case of morbid obesity, and one case of Pierre Robin anomaly. The rest was unexpected. Switching from endotracheal intubation to HFPPV allowed adequate exposure in 12 patients while preserving magnification and bimanual instrumentation. Ten cases were able to be done with MDL using a diagnostic narrow-bore diagnostic (Holinger) laryngoscope. When the above approaches fail, an angled telescope with an angled cup forceps was able to reach the lesion in two cases. Finally, one patient who could not be intubated was managed with a flexible laryngoscope through the LMA device.

Difficult exposure during MDL is unusual but not rare. It is often unanticipated. A proposal for graded use of the four techniques preserves some advantages of MDL. With each escalation, there is a degradation of the advantages afforded by traditional MDL. These include minor increase in movement with HFPPV, loss of binocular visualization with diagnostic laryngoscopes, loss of bimanual instrument manipulation with the telescopes, and loss of stability with flexible laryngoscopy. Having an understanding of each technique and the need for escalation will allow the surgeon to perform rescue laryngoscopy and complete the surgery.