Subcutaneous paravertebral block for renal colic.

A 26-yr-old woman, with an intrauterine pregnancy at 29 6⁄7 weeks’ gestation, presented to the emergency room of The Milton S. Hershey Medical Center reporting severe pain in the right flank. Abdominal ultrasound did not show a renal or ureteral calculus, but delayed contrast filling of the right urinary collecting system seen on an abdominal computed tomography scan was consistent with right ureteral obstruction. The patient was admitted to the obstetrics ward for pain control and observation, with plans to perform percutaneous nephrostomy if the ureteral obstruction did not resolve. Despite administration of 150 mg meperidine and 8 mg morphine intravenously over a 4-h period, the patient reported persistent severe pain, prompting consultation with the Acute Pain Management Service. The Acute Pain Management Service performed a subcutaneous paravertebral field block in the following manner. The patient was placed in the left lateral decubitus position. Using the inferior angle of the scapula and the iliac crest as landmarks for T7 and L4 spinal levels, respectively, the T10 and L2 spinous processus were identified. After sterile preparation of the skin, a continuous subcutaneous weal of 2% lidocaine (6 ml) was created 4 cm to the right of midline, extending between T10 and L2 using a 1⁄2-in 25-gauge needle (fig. 1). Before the injection, the patient reported her pain as 10 of 10 according to the visual analog scale (VAS). Five minutes after the injection, the pain was 2 of 10, and 5 min later it was 0 of 10. The patient was pain free for 2 h. Pain gradually returned, and the block was repeated when the pain score reached 7 of 10. For the second block, 6 ml bupivacaine, 0.25%, was infiltrated. Again the pain score decreased to 0 of 10 for 2 h. When the pain score reached 6 of 10, intravenous meperidine (75 mg) was administered to the patient. Two hours later, with a pain score of 1 or 2 of 10, the patient was brought to the radiology department for percutaneous nephrostomy, which was unsuccessful because of an inability to access the renal pelvis. Then, the patient was brought to the operating room for cystoscopy with ureteroscopy and ureteral stent placement during spinal anesthesia. The next day the patient was discharged free of pain with the ureteral stent in place. Discussion