COMPLICATIONS OF LOCAL ANESTHESIA
Peribulbar block is usually preferred over retrobulbar. So most commonly used method is peribulbar [PGI 98]. It consists of infiltration of anesthetic agent around the globe [PGI 98].
Q) why retrobulbar is not preffered ?
as it involves infiltration of anesthetic material behind the globe ,it carries risk of damage to optic nerve and bleeding from retroorbital blood vessels.
OTHER COMPLICATIONS; 1)Globe perforation 2)oculocardiac reflex ) intracranial spread of anesthetic agent leading to seizure.
Q) What is oculocardiac reflex ?
cardiac arrythmias arising from traction on extraocular muscles or pressure on eyeball. Trigeminal nerve acts as its afferent and vagal as its efferent. it can occur during any eye surgery but is most common during strabismus surgery on peditric patient.(page 763 lange clinical anesthesiology 3rd ed).
Q) which of the following increase IOP ?
A] NITROUS OXIDE
ANS; [C] ref page 763 lange clinical anesthesiology 3 ed)
COMPLICATIONS DURING OPERATION;
1] Superior rectus muscle laceration and/or hematoma during applying bridle suture . NOTE ; temporal clear corneal incision eliminate the need of working over brow and so bridal suture is not required. it is done in phako.
2] complications that may occur during creation of self sealing valvular sclero corneal tunnel incision which is made in SICS and PHAKOEMULSIFICATION. (a) button holing of anterior wall (b) premature entry into anterior chamber (c)scleral disinsertion.(q)= NOTE; if any of these occur the dissection at that site is abandoned and dissection is started at new site.
3] injury to cornea which leads to post oprative corneal edema.
Q] Which of following do not predispose to post operative corneal edema?
a)intraop mechanical endothelial trauma from instruments
b) prolonged postoperative elevation of IOP
c) incomplete removal of the viscoelastic substance
ANS; [C] incomplete removal of viscoelastic substance do not lead to corneal endothelial loss. so it will not lead to post op corneal edema. [ref ; OPTHALMOLOGY REVIEW, YANOFF 2ND ed page 49]
4] IRIS INJURY and IRIDODIALYSIS and intraop IRIS PROLAPSE. CAUSES OF INTRAOP IRIS PROLAPSE (a) entering anterior chamber too posteriorly near iris root (b) patient use of systemic tamsulosin for their urinary problem (c) impending choroidal effusion or expulsive hemorrhage.
5] anterior capsulorhexis : if a small capsulorhexis is made it predisposes to (A) posterior capsular tear and nuclear drop (B) zonular dehiscence. [ khurana 4thed page 198]
NOTE: deep anterior chmber should be maintained during anterior capsulorhexis which prevents tension on anterior zonules and there by prevents zonular dehiscence. it also prevents radial tear in ant capsule during capsulorhexis.
6] POSTERIOR CAPSULAR RUPTURE; As posterior capsule is removed in ICCE so it can never occur in ICCE [PGI 95]. it can lead to nuclear drop into posterior vitrous especially in PHACOEMULSIFICATION. It can also lead to posterior loss of lens fragments.
MANAGEMENT; If nuclear drop occurs it should be managed by vitroretinal surgeon.
Q] What will u do if a lens remnant is noted in the inferior vitrous compartment postoperatively in a “quiet eye” ? if signs of inflamation is absent as here then patient can be followed up with topical steroids as the lens material will get absorbed with time . [ref; opthalmology review ,yanoff, page61]. if signs of inflamation is present it shows impending phacoanaphylactic endopthalmitis or phacolytic glaucoma.
PART 2 COMING SOON