Abstract
Purpose:
Small gauge vitrectomy has become the standard of care for most vitreo-retinal procedures. Removal of silicone oil through small gauge cannula may be associated with prolonged removal time, influencing surgeon’s preferred method of removal of silicone oil. The purpose of the current study was to evaluate the time taken for removal of silicone oil through 23 gauge and 25 gauge cannula systems.
Methods:
Interventional, non-comparative, clinical case series. Participants included patients undergoing removal of silicone oil as part of their vitreoretinal procedure. The silicone oil was removed using the automated viscous fluid extraction device (Alcon Constellation) at standard settings (Vacuum 650 mmHg, intraocular pressure 35 mmHg). Time taken to remove 1 ml of silicone oil using the "extraction sleeve" or the cannula was measured for each case. Typically, for each case two measurements were obtained using the "extraction sleeve" and two measurements were obtained using the cannula. The two values were averaged for each case.
Results:
Twenty nine eyes. Group 1: 25 gauge, 1000 cs silicone oil. N=14. The mean time for removal of silicone oil was 25.5 seconds/ml (SD 1.3 ) for the "extraction sleeve", and 38.4 seconds/ ml (SD 2.1 ) for the cannula. Group 2: 23 gauge, 1000 cs silicone oil. N= 12. The mean time for removal of silicone oil was 12.5 seconds/ml (SD 1.0 ) for the "extraction sleeve" , and 22.1 seconds/ ml (SD 1.6 ) for the cannula. Group 3: 23 gauge, 5000 cs silicone oil. N= 3. The mean time for removal of silicone oil was 49.8 seconds/ml (SD 3.4) for the "extraction sleeve", and 92.3 seconds/ ml (SD 4.1 ) for the cannula. Assuming an average of 4.5 ml volume of silicone oil in the vitreous cavity, the estimated average time for removal of 1000 cs silicone oil would be 115 seconds for 25 G "extraction sleeve", 173 seconds for 25 G cannula, 56 seconds for 23 G "extraction sleeve", and 99 seconds for 23 G cannula. For 5000 cs silicone oil, the estimated average time for removal of silicone oil would be 224 seconds for 23 G "extraction sleeve", and 415 seconds for 23 G cannula.
Conclusions:
Removal of 1000 cs silicone oil through small gauge cannula systems is associated with an acceptable time ranging from an estimated average time of 56 seconds for a 23 G "extraction sleeve" to 173 seconds for a 25 G cannula. For the 5000 cs silicone oil the estimated average time was significantly higher.
Keywords: 762 vitreoretinal surgery •
764 vitreous substitutes •
697 retinal detachment