Ultrasound-guided multiple-injection costotransverse block for mastectomy and primary reconstructive surgery. A study protocol.

BACKGROUND: Post-operative pain amelioration following breast cancer surgery is inconsistent. The novel multiple-injection costotransverse block (MICB) mimics the thoracic paravertebral block by possible anaesthetising the ventral rami of the thoracic spinal nerves and the sympathetic trunk. Proof of concept has been determined in a cadaveric study and needs further clinical testing. METHODS: This double-blinded, randomised and placebo-controlled study investigates the efficacy of the ultrasound-guided MICB versus placebo in 36 patients undergoing unilateral mastectomy and primary subpectoral reconstruction surgery. Oral pre-operative medicine is standardised for all patients. Active group is pre-operatively administered MICB with three injections of each 10 ml of ropivacaine (5 mg/ml). The placebo group is pre-operatively administered three injections of each 10 ml of saline (0.9%). Standard general anaesthesia is induced and 30 min before emergence 0.2 µg/kg total body weight sufentanil IV, 1 g of paracetamol IV and 4 mg of ondansetron IV (post-operative nausea and vomiting, PONV, prophylaxis) will be administered. All patients are provided with a patient-controlled analgesia pump with morphine. The primary aim is total morphine consumption in the first 24 post-operative hours. Secondary aims are pain intensity, duration of the block, patient satisfaction, side effects, time to ambulation, time to discharge, and quality of recovery. DISCUSSION: Recruitment began in November 2019 and is expected to finish ultimo 2021. Results are expected to be published in an international peer-reviewed medical journal. The results will hopefully provide a substantial contribution to the knowledge of these new 'intertransverse process blocks' providing regional anaesthesia of the thoracic wall.

Transmuscular quadratus lumborum block for percutaneous nephrolithotomy: Study protocol for a dose-finding trial.

BACKGROUND: The objective of this trial is to optimize the transmuscular quadratus lumborum (TQL) block, by investigating the minimal effective volume (MEV90 ) of ropivacaine 0.75% for single-shot TQL block in percutaneous nephrolithotomy (PNL) patients. METHODS: This double-blind, randomized and controlled dose-finding trial is based on a biased coin up-and-down sequential design, where the volume of local anaesthetic administered to each patient depends on the response from the previous one. Investigating the TQL block, the first patient recruited receives 20 ml ropivacaine 0.75% preoperatively. In case of block failure, the next patient will receive the same volume with an increment of 2 ml. Given a successful block for the first patient, the next patient will be randomized to either a lower volume (previous volume with a reduction of 2 ml), or the same volume as the previous patient. The respective probabilities being b = 0.11 for a reduced volume and 1-b = 0.89 for the same volume. Block success is defined as patient reported pain score numeric rated scale (NRS) ≤3 (0-10/10) 30 minutes after arrival in the post anaesthesia care unit (PACU). The NRS pain score is our primary and only outcome for block success. A minimum of 25 eligible patients are needed to achieve precise estimation of MEV90 with narrow 95% confidence intervals derived by bootstrapping. DISCUSSION: Recruiting will begin June 2020 and is expected to finish November 2020. Data analysis will be performed at interims during and after the study. Results will be published in an international peer-reviewed medical journal.