Needle entrance into the maxillary sinus during retrobulbar anesthesia.

Three patients are presented to whom an accidental needle entrance into the maxillary sinus occurred during retrobulbar anesthesia. In all cases air was aspirated during the aspiration check at the end of needle advancement, and the patients reported a bitter taste after the injection of a small quantity of anesthetic. After withdrawal and careful reinsertion of the needle, maxillary sinus entrance was avoided and a successful retrobulbar block was achieved. Two of the patients had no history of previous facial trauma or surgery, whereas the third had suffered a recent blowout fracture of the orbital floor. The authors suggest that air aspiration or anesthetic passage into the pharynx during retrobulbar anesthesia should raise the suspicion of maxillary sinus entrance, even in patients without any history of facial trauma or surgery. The early recognition of sinus entrance can prevent retrobulbar block failure and reinjection of a second anesthetic dose.

Histological evaluation of phthalocyanine mediated photodynamic occlusion of corneal neovascularization enhanced by hyperbaric oxygenation.

PURPOSE: We evaluated the effective irradiation parameters for photodynamic thrombosis of experimental corneal neovascularization enhanced by simultaneous hyperbaric oxygenation. METHODS: Neovascularization was provoked in both eyes of each of 35 albino rabbit corneas using the intracorneal suture technique. The lasered animals were divided in 3 groups. Group 1 (10 rabbits) was treated under hyperbaric conditions (28 atm for 25 min.); group 2 (5 rabbits) was treated breathing pure oxygen delivered by a face mask; group 3 (10 rabbits) was treated breathing room air. The fourth group (10 rabbits) was used for control. Animals were anaesthetized, and irradiation of new corneal vessels was carried out 30 minutes after the injection of 5 mg/kg chloroaluminum sulfonated phthalocyanine. A 670 nm diode laser with a power 4 mW and a spot diameter 350 mm was used. Exposure times necessary for vascular occlusion were registered. Histological examination was carried out at the end of the follow-up time. RESULTS: Exposure times were significantly lower in groups 1 and 2 as compared to group 3 (1.75 +/- 0.15 min., 3.1 +/- 0.4 min., and 4.75 +/- 0.15 min. respectively). Total light dose averaged 490 J/cm,2 870 J/cm,2 and 1330 J/cm,2 respectively. Histological examination revealed thrombus formation in the targeted vessels of all three investigated groups. CONCLUSION: Combination of PDT with hyperbaric oxygenation results in an acceleration of the photodynamic process and provides for a possibility of significant reduction of photodynamic dose.