Presentation on theme: "Retrobulbar Block. Introduction Commonly used for intraocular procedures including those involving cornea, lens, and anterior chamber. Goals of the retrobulbar."— Presentation transcript:
Introduction Commonly used for intraocular procedures including those involving cornea, lens, and anterior chamber. Goals of the retrobulbar block – Akinesia Extraocular muscle paralysis – Anesthesia conjunctivae, cornea, uvea
Contraindications Absolute CI’s – Patient refusal – Infection Relative CI’s – <15 y/o – Globes with high risk of perforation (large axial length) – Relatively long procedures (90 min) – Cough, tremor, convulsive disorder, anxiety, others
Innervation Motor – Abducens (CN VI) – Trochlear (CN IV) – All others (CN III) Sensory – Ophthalmic division of CN (V) Lacrimal branch: conjunctiva Nasociliary branch: cornea, sclera, iris, ciliary body. Ciliary Ganglion (parasympathetic) – Supply ciliary body and pupillary schinter muscles Retrobulbar blockade affects all of the above except for cranial nerve IV.
Preperation Alcohol prep pads 4 x 4 gauze 50/50 mix 0.75% Marcaine and 2% Lidocaine. Also, lidocaine 1% and bupivicaine 0.375%. 5 cc syringe Atkinson 25 guage retrobulbar needle with blunt tip.
Preparation Ask patient to look straight ahead (not upward) Clean lower lid with prep wipe Can ask an assistant to pull up on upper lid to watch for movement Palpate inferior orbital margin for infraorbital notch (2/3 distance from medial aspect) Make skin wheel just lateral to notch
Procedure Advance block needle straight down at site of wheel, perpendicular to plane of face, until you encounter distinct pop. Angle block needle 45 medially and 45 superiorly, toward apex Advance until 2 nd pop Aspirate for blood Inject 2-3 mL of anesthetic solution Note proptosis
Procedure Cont’d Withdraw and inject 1ml under skin as you withdraw (orbicularis) Gently massage of globe to spread local evenly throughout the orbit – Monitor for bradycardia (late bradycardia also possible); atropine.4 to.6 mg IV Test block
Complications Retrobulbar hemorrhage – Observe for increasing proptosis, subconjunctival blood – Puncture of blood vessel in retrobulbar space – Causes sudden increase in IOP, subconjunctival hemorrhage, ecchymoses over eyelids – Postpone surgery 2-4 days Oculocardiac reflex Central retinal artery occlusion Punctured globe Penetration of optic nerve Unintended brainstem anesthesia