Oculomotor nerve and Levator palpebrae Superioris muscle in relating to temporary ptosis following blepharoplasty

초록

Transient diplopia, blepharoptosis, or both are rare postoperatively complications of blepharoplasty done under local anesthesia. Rainin and Carloson hypothesized that some cases of postoperative diplopia and blepharoptosis could be attributed to myotoxic effects of local anesthetics to extraocular muscles or levator muscle. Kalichiman contended that the local anesthetic, lidocaine, is neurotoxic. In 30 cadavers the superior division of N. Ⅲ was severed 1.5cm anterior to annulus of Zinn en block with Levator palpebrae superioris(LPS) and Superior rectus, which were detached from their origins, the attachments onto the sclera and tarsal plates were divided, respectively. The specimens were treated in the guanidine-HCl and alizarin red solution, and dissected under an operating microscope. The nerve branches of the superior division of oculomotor nerve innervated the proximal 1/3(TypeⅠ) in 2 of 30 LPS muscles (6.7%)and in 8 (26.7%) extended to the middle 1/3 (TypeⅡ) and reached the distal 1/3 (Type Ⅲ) in 20 of 30(66.7%). The terminal branches run through medial 1/3 (Type Ⅲ-a) in 6 of 20 Type Ⅲ LPS muscles(30%), central 1/3(Type Ⅲ-b) in 8(40%) and lateral 1/3 (Type Ⅲ-c) in 6(30%). The oculomotor nerve ends extended forward to distal third of LPS muscle (Type Ⅲ) is exposed vulnerable to local anesthetics and may be numbed in blepharoplasty. Presumption that the postoperative blepharoptosis may be caused by transient paralysis of LPS muscle mandates great care in injection of local anesthetics near the LPS