Title: Ultrasound guided thoracic paravertebral block for open partial nephrectomies.
Introduction: Traditionally thoracic epidural (TE) is performed for postoperative pain relief for open partial nephrectomy procedures. Thoracic epidural provides effective intra and postoperative analgesia, but have associated side effects like hypotension, failure of analgesia and urinary retention. The biggest challenge is the placement of thoracic epidural in certain patients. Thoracic paravertebral block (TPVB) provides equal analgesic benefit as epidural in these procedures, technically easier to perform with ultrasound guidance, associated with fewer complications and less side effects [1, 2].
Materials & Methods: The patients scheduled for open partial nephrectomy are consented for thoracic paravertebral block preoperatively. They are positioned prone with standard monitoring and ultrasound guided thoracic paravertebral block on the same side of the intended open partial nephrectomy is performed in the block room preoperatively. With a curvilinear low frequency probe, T9 or T10 thoracic paravertebral space is identified, a transverse approach is used in our patients. T9 or T10 transverse process is identified, the probe is moved little caudad, the superior costo transverse ligament and pleura are identified as two bright hyper echoic white lines . The moving white hyper echoic white line is identified as pleura; the thoracic paravertebral space (TPVBS) [2, 3] is located beneath the superior costo transverse ligament and above the pleura. A 17G echogenic needle is inserted in plane from lateral to medial direction with transverse approach, hydro location is used to identify needle tip if visualization is difficult. Pleural depression is taken as positive sign, local anesthetic ropivacaine 0.5% 10 ml is injected, continuous nerve catheter is placed in the TPVBS. Colour Doppler is used to locate the catheter tip and 5 ml of 0.5% ropivacaine is given via catheter for final confirmation of catheter position. Continuous postoperative analgesia is provided by running ropivacaine 0.2% at 8 ml/hr with 5ml bolus every 60 min as needed with patient controlled thoracic paravertebral analgesia. The continuous nerve catheter infusion is stopped post operatively when the patient is tolerating oral pain medications and pain under control.
Results: All the patients have unilateral incision along the 11th costal margin extending just lateral to midline. The TPVB is tested preoperatively after the initial bolus with ropivacaine. Using ice the dermatomes involved with incision are checked and feeling numb is taken as successful block. Continuous analgesia is provided with LA infusion, pain scores are recorded until the catheter is taken out. Breakthrough pain not relieved by TPVB bolus dose is treated with IV dilaudid. A series of 10 patients are being followed with the TPVB. The pain scores on average were 2-4, 24 hour and total dilaudid consumption was low, patient satisfaction with pain relief was excellent. The incidence of hypotension, nausea and urinary retention was low. There was no technical difficulty in placing TPVB and the failure rate was zero. There were no procedural complications with the TPVB . Transition to oral pain regimen was smoother and patient rehabilitation was much better with TPVB.
Discussion: Thoracic paravertebral block provides effective pain relief for open partial nephrectomies. TE performed for pain relief is associated with more side effects compared to TPVB. TE is more challenging to perform, associated with failure of analgesia. Ultrasound guided thoracic paravertberal block  is easier to perform, provide analgesic benefit as thoracic epidural. TPVB enables to provide effective post operative analgesia with continuous catheter infusion with local anesthetics, reduces parental opioid consumption and side effects associated with the opioids. TPVB reduces undesired side effects like bilateral analgesia, hypotension and urinary retention. Patient mobility is better with TPVB which can contribute to low incidence of deep vein thrombosis. Ultrasound guided TPVB increases the success rate of the block and reduces the procedural complications. Further randomized studies are needed to confirm the advantages of TPVB over TE for these procedures.
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