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Background Postoperative epidural analgesia provides superior postoperative analgesia at rest and with activity, compared with systemic opioids. However, the impact of postoperative epidural analgesia on postoperative morbidity and/or mortality remains controversial, because of the sub-optimal reliability of epidural catheters that are placed preoperatively and used for postoperative pain control. The present study used the technique of lumbar epidurography. The study aims to better understand the possible correlation between the fluoroscopic characteristics of epidural catheters following injection of contrast medium and the postoperative functional characteristics regarding analgesia. In this single-arm clinical trial, 70 patients, aged 50 to 75 years old, underwent surgical urological procedures, involving incisions up to T8 dermatome, under combined general and epidural anesthesia. At the L2-L3 level, the epidural space was reached using the loss of resistance technique before general anesthesia was induced. The catheters were threaded upwards for 4–6 cm. Preoperative epidurograms were then done by injecting a 3-ml contrast medium OmnipaqueTM (240 mg I/ml) in the epidural catheters. The epidurograms were investigated for the location of the catheter tip in relation to the vertebral body, the extent of dye spread, laterality of dye spread (midline, right, or left), and the presence or absence of dye spread anterior to the spinal cord on the lateral image. The patients were followed postoperatively while epidural analgesia was infused. Results Both the postoperative epidural infusion and postoperative visual analog scale (VAS) scores were lower when catheter tips ended at L1 than when they ended at L2. As the contrast’s vertical spread increases in preoperative epidurograms, the analgesic infusion rate and VAS score decrease, and the number of dermatomes insensitive to cold increases. Epidurographically right-sided catheters showed more dermatomes deficient to cold sensations on the right side, compared with mid-line and left-sided catheters. Restriction of contrast to the posterior epidural space was associated with lower VAS scores and wider anesthesia to cold. Conclusions The use of epidurography to study epidural catheters may have the potential advantage of predicting the functionality of catheters and improving the reliability of postoperative epidural analgesia.

Background Peribulbar Anesthesia (PBA) is a relatively safe method for cataract surgery. The anesthetic volume should be adjusted according to the axial eyeball length. Thus, using Minimum Effective Volume (MEV) of local anesthetic helps avoiding unnecessary volumes, preventing increases in intra-ocular pressure, and producing satisfactory conditions for cataract surgery. This study aims to determine the MEV90 of local anesthetics in relation to eye globe axial length in peribulbar blocks for cataract surgery. Methods Patients scheduled for cataract extraction under local anesthesia were divided according to their axial eyeball length; Group 1 included those with axial length from 22 to 24 mm, Group 2 included patients with axial length from 24.1 to 26 mm. The initial volume used was 7 mL of a solution of bupivacaine 0.5% (3 mL) + lidocaine 2% (3 mL) + hyaluronidase 150 IU (1 mL). The subsequent volumes were dependent on the response of the previous patient, by using a Bias Coin Design (BCD) and Up and Down Method (UDM) for MEV-90 determination. Results The study was concluded with 119 patients. Sixteen patients needed supplemental volume of local anesthetic in Group 1 and thirteen in Group 2. The MEV90 for Group 1 was approximately 5.82 mL (95% CI 5.6 to 5.87 mL) and 5.45 mL for Group 2 (95% CI 5.38 to 5.91 mL). No major complications were noted. There was a negative correlation between the effective volume of LA and eye globe axial length in both groups (p = 0.001). Conclusion The MEV90 of local anesthetics for peribulbar block show a strong and inverse correlation with eye globe axial length. This may help achieving an effective block with minimum complications.