Nasolacrimal evaluation and surgery.

The lacrimal drainage system is a very important functional and anatomic assembly in the orbit and midface. For surgeons who intend to become involved in its repair or reconstruction, it is mandatory to understand the full range of anatomic, physiologic, and diagnostic considerations prior to embarking upon a surgical course. Proper eyelid function depends upon the integrity of its constituent parts, including the margin, tarsus, muscle, and globe apposition. The lacrimal pump mechanism is produced by proper eyelid function and structure, and must be adequately assessed. The puncta and canaliculi are delicate structures and must be manipulated with care and gentleness. The lacrimal sac is a static structure that serves as a collecting sphere but also may be forced to evacuate its contents into the nasolacrimal duct by the "squeezing" action of the investing tendons. Proper tendon position must be maintained after surgery or trauma to facilitate this action. The nasolacrimal sac may be damaged after facial fractures or blocked from intranasal conditions. If the blockage cannot be relieved, it must be bypassed by performing a dacryocystorhinostomy. The use of long-term, indwelling silicone intubation catheters greatly facilitates the successful reconstruction of the lacrimal drainage system. Proper attention to all of these points will be appreciated by the patient.