[Corneal endothelial cell loss after phacoemulsification in relation to hydrodynamic parameters: low versus high vacuum techniques]

To evaluate the effect of vacuum and flow rate on endothelial cell loss after high versus low vacuum phacoemulsification. This randomized clinical trial was performed on 60 eyes of 60 patients with moderate lens opacity [nuclear sclerosis 3+]. All surgeries were performed by one experienced surgeon using stop and chop technique with Sovereign white star machine [AMO]. Patients were randomly assigned to high and low vacuum techniques in equal numbers. The machine was set on 400 mmHg vacuum and 40 ml/min flow rate in the high vacuum group and on 200 mmHg vacuum and 20 ml/min flow rate in the low vacuum group during the chop stage. All other parameters were similar in both groups. Phacotime multiplied by average ultrasound power was defined as total ultrasound energy. Specular microscopy was performed before and 1, 6 and 12 weeks after the operation. After 12 weeks, mean endothelial cell loss was 9.0 +/- 4.0% versus 9.6 +/- 4.6% in the low and high vacuum groups, respectively [P=0.6]. Mean ultrasound power was 9.2 +/- 4.3% and 13.1 +/- 4.6% in the low and high vacuum groups, respectively [P=0.001]. Mean phacotime was 1.28 +/- 1.0 minutes in the low vacuum group versus 0.88 +/- 0.6 minutes in the high vacuum group [P=0.04]. Total ultrasound energy and total fluid volume used [turbulence] during phacoemulsification was similar between the two study groups. Total ultrasound energy was the most powerful predictor of endothelial cell loss [R2=0936, P=0.001], but turbulence was not a significant predictor [R2=0.924, P=0.1]. No significant difference in endothelial cell loss was found between low and high vacuum techniques. This study supports advice to junior surgeons to choose lower hydrodynamic phaco machine parameters; experienced surgeons can choose higher parameters to reduce phacotime

[Risk factors for posterior capsular tear and vitreous loss during phacoemulsification in a tertiary eye center]

To report the rate of vitreous loss during phacoemulsification and its contributing risk factors in patients operated on at Labbafinejad Medical Center. This prospective comparative descriptive study included patients with cataract undergoing phacoemulsification by ophthalmology residents or cornea fellows from November 2006 to November 2007. All patients underwent a complete ocular examination including visual acuity, slitlamp examination, and dilated funduscopy, preoperatively. Phacoemulsification was performed under local or general anesthesia using Divide and Conquer technique. Main outcome measures included posterior capsular tear and vitreous loss and predisposing factors such as surgeon's experience, ocular and systemic conditions, and type and severity of the cataract. Overall 767 patients including 393 male and 374 female subjects with mean age of 62.7 +/- 12.0 [range 6-96] years were studied. The overall rate of vitreous loss was 7.3% which was 5-fold higher in the hands of residents than fellows. Patients' age and female sex, small capsulorrhexis, small pupil, pseudoexfoliation, and high myopia were other significant risk factors. The highest rate of vitreous loss occurred in patients with dense nuclear cataracts. Since ophthalmology residents had a higher rate of vitreous loss, patients with risk factors such as pseudoexfoliation, high myopia, and dense nuclear cataracts are better operated by more experienced surgeons

Mean intercondylar notch width index in cases with and without anterior cruciate ligament tears

It has been proposed that a narrow intercondylar notch may increase the risk of anterior cruciate ligament [ACL] injury but the data are conflicting. We performed this cross-sectional study to investigate if a narrow intercondylar notch width is a risk factor for ACL tears. All adult patients with knee problems, who were referred to the MRI department of Poursina Hospital, Rasht, Iran, from October 2006 to October 2007, were included in this study. Axial and longitudinal MRI were performed using a 1-T Phillips machine with the patient's knee in an extended position. In all patients, the femoral notch and the distal condylar width were measured. Cases with normal ACL were used as control and patients with a complete or incomplete tear of ACL were chosen as case group. Because of the effect of osteoarthritis in decreasing the intercondylar notch index, cases with obvious osteoarthritis were not included in the study. Independent sample Student's t test was used to compare the means. 328 patients were enrolled in the study. The age range was 18-72 years. We found no significant difference in the mean notch width index [NWI] in patients with [0.296] and without [0.298] an ACL tear [P>0.05]. In addition, there was no significant difference in the frequency of ACL tears in patients with and without critical notch stenosis [P>0.05]. We did not find a relationship between narrow intercondylar notch width and ACL tears and we do not recommend a knee MRI to predict the probability of ACL injury

Posterior lschemic optic neuropathy following percutaneous nephrolithotomy

To report a case of posterior ischemic optic neuropathy [PION] following percutaneous nephrolithotomy [PCNL]. A 57-year-old male who underwent PCNL because of renal stone was referred due to painless bilateral visual loss to the level of light perception immediately after the operation. The patient had history of diabetes mellitus, hyperlipidemia, and mild anemia. Ophthalmic examinations were unremarkable and optic discs were pink and without any sign of swelling. Visual fields were severely affected, but neuro-imaging was normal. Within three months, visual acuity and visual fields improved dramatically and optic discs became mildly pale. The clinical course was typical for PION. PION is a rare cause of severe visual loss following surgery. Severe blood loss, hypotension, anemia, and position of the patient during surgery are the most important risk factors. This is the first report of PION following PCNL. Urologists, ophthalmologists and anesthesiologist should be aware of this entity, and rare possibility should be discussed with the patient before surgery. Preventive measures against PION should also be taken