Plantar compartment block for hallux valgus surgery: a proof-of-concept anatomic and clinical study.

BACKGROUND: Hallux valgus surgery is associated with moderate to severe postoperative pain. We hypothesized that a plantar compartment block may be a good technique for postoperative analgesia. We describe an anatomic approach to ultrasound-guided plantar compartment block and assess the clinical efficacy of the block for outpatient surgery. METHODS: The anatomic study was aimed to describe the plantar compartment, using both dissection methods and imaging, and to define a volume of local anesthetic. Patients scheduled for hallux valgus surgery with a popliteal sciatic nerve block, and combined plantar compartment and peroneal blocks were included in the clinical study. Data on attaining the criteria for rapid exit from the outpatient center, duration of sensory and analgesic block, visual analog scale (VAS) values for postoperative pain at rest and during movement, and the consumption of morphine as rescue analgesia were recorded. RESULTS: Plane-by-plane dissections and cross-sections were done in five cadaveric lower limbs. The medial calcaneal nerve divides into medial plantar and lateral plantar nerves in the upper part of the plantar compartment. These nerves were surrounded by 5 mL of colored gelatin, and 10 mL of injectates dye spread to the medial calcaneal branches. Thirty patients (26 women) were included in the clinical study. There were no failures of surgical block. Ninety per cent of patients successfully passed functional testing for ambulatory exit from the center within 5 hours (25th-75th centiles, 3.8-5.5 hours). The median duration of plantar compartment sensory block was 17.3 hours (10.5-21.5 hours), and the first request for rescue analgesic was 11.75 hours (10.5-23 hours) after surgery. The median VAS score for maximum pain reported within the 48-hour period was 2 (1-6). Twelve patients received 2.5 mg (0-5 mg) of morphine on day 1. Patients were highly satisfied and no adverse events were noted. CONCLUSIONS: This anatomic description of the ultrasound-guided plantar compartment block reported the injection area to target the medial and lateral plantar nerves with 5 mL of local anesthetic. Normal walking without assistance is attained rapidly with this regional anesthesia technique, and the time to request postoperative analgesia after hallux valgus surgery is long. TRIAL REGISTRATION NUMBER: NCT03815422.

Impact of multiple nerves blocks anaesthesia on intraoperative hypotension and mortality in hip fracture surgery intermediate-risk elderly patients: A propensity score-matched comparison with spinal and general anaesthesia.

BACKGROUND: A Hip fracture in the intermediate-risk elderly patient is common and associated with a high rate of postoperative morbidity and mortality. There is a lack of consensus on the optimal anaesthetic technique but there is a clear association between intraoperative hypotension and postoperative morbidity and mortality. We aimed to compare the haemodynamic stability of three anaesthesia techniques: general anaesthesia (GA), continuous spinal anaesthesia (CSA), and multiple nerve blocks (MNB). METHODS: The primary outcome was the occurrence of intraoperative hypotension defined by a 30% decrease in mean arterial pressure (MAP) from baseline. Secondary outcomes included incidence of hypotension under 50 mmHg of MAP, time spent below MAP 50 mmHg, use of vasopressors, in-hospital and 30-day mortality. A propensity score-matched analysis was performed. RESULTS: After screening and application of the exclusion criteria, 593 patients undergoing hip fracture surgery between the 1st of January 2015 and the 31st of December 2016 were included. The propensity score match analysis selected 43 patients in each group. The incidence of hypotension was significantly higher in the GA group than in the MNB and CSA groups: 39 (90%), 22 (51%), and 23 (53.5%), respectively; p < 0.0001. The incidence of MAP < 50 mmHg (59.5%, 23.3%, and 16.3%; p < 0.0001) and the use of vasopressors (93%, 39.5%, and 25.6%; p < 0.0001) were increased significantly in the GA group. With the GA group as a reference, odds ratios were reported in the MNB group at 0.08 [0.022-0.30] (p = 0.0002) for hypotension episodes; 0.17 [0.04-0.66] (p = 0.01) for hypotension < 50 mmHg for more than 3 min and 0.049 [0.013-0.018] (p < 0.0001) for use of vasopressors. The duration of hospital stay, postoperative complications, in-hospital and 30-day mortality rates did not differ significantly between the groups. CONCLUSION: CSA and MNB provide better haemodynamic stability than GA. However, whatever the anaesthesia technique used, the mortality rates do not change even if MNB leads to less hypotension. IRB contact information: CERAR IRB 00010254-2016-118. Clinical Trial Number: ClinicalTrials.gov. ID: NCT03356704.

Combination of real-time needle-tip pressure sensing and minimal intensity stimulation limits unintentional intraneural injection during an ultrasound-guided peripheral nerve block procedure: A randomized, parallel group, controlled trial.

STUDY OBJECTIVE: Ultrasound guidance does not eliminate the risk of intraneural injection, which must be avoided during PNB. Combining ultrasound guidance (USG), nerve stimulation (NS), and injection pressure monitoring is advocated to prevent nerve injury during PNB. We hypothesized that combining patient-tailored dynamic NS and real-time pressure sensing (RTPS) could reduce the incidence of intraneural injection and nerve puncture during USG PNB compared with a traditional fixed thresholds (Control) procedure. DESIGN: Randomized, prospective study. SETTING: Operating room. PATIENTS: One hundred ASA physical status I to III patients undergoing orthopedic surgery. INTERVENTIONS: Patient anesthetized using axillary, sciatic or femoral USG PNB were randomized to the PresStim group (Dynamic RTPS and NS set at 1.5 mA then decreased; n = 50) or Control group (fixed thresholds for in-line pressure mechanical manometer and NS at 0.2 mA; n = 50). MEASUREMENTS: Procedural ultrasound images and videos were recorded, stored and reviewed in random order by two experts in ultrasound-guided PNB blinded to the group. They noted the needle-to-nerve relationship and intraneural injection for all blocked nerves. MAIN RESULTS: One hundred and twenty-three USG PNBs were performed (56 axillary brachial plexus blocks, 40 femoral nerve blocks and 27 sciatic popliteal nerve blocks); 235 blocked nerves and videos were recorded and analyzed (PresStim, 118; Control, 117). Less paresthesia was noted in the PresStim group (12.7%) compared with the Control group (18.8%). The risk of intraneural injection was significantly higher in the Control group (odds ratio [OR], 17.1; 95% confidence interval [CI], 2.2-135, P = 0.007). The risk of nerve puncture (OR, 22.7; 95% CI, 2.9-175, p = 0.003) and needle-nerve contact (OR, 4.7; 95% CI, 2.4-9.5, p < 0.001) was significantly higher in the Control group than the PresStim group. CONCLUSIONS: Under the conditions of the study, dynamic triple monitoring combining RTPS, NS and USG decreases intraneural injection and unintentional needle-nerve contact and puncture during a PNB procedure.

Posterior Quadratus Lumborum Block in Total Hip Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Pain management is important for ensuring early mobilization after hip arthroplasty; however, the optimal components remain controversial. Recently, the quadratus lumborum block has been proposed as an analgesic option. The current study tested the hypothesis that the posterior quadratus lumborum block combined with multimodal analgesia decreases morphine consumption after hip arthroplasty. METHODS: This study was a prospective, randomized, double-blind, placebo-controlled trial. Before general anesthesia, 100 participating patients scheduled for elective total hip arthroplasty were randomly allocated to receive a 30-ml injection posterior to the quadratus lumborum muscle with either 0.33% ropivacaine (n = 50) or normal saline (n = 50). For all patients, multimodal analgesia included systematic administration of acetaminophen, ketoprofen, and a morphine intravenous patient-controlled analgesia. The primary outcome was total intravenous morphine consumption in the first 24 h. Secondary outcomes recorded intraoperative sufentanil consumption; morphine consumption in the postanesthesia care unit; pain scores at extubation and at 2, 6, 12, and 24 h; motor blockade; time to first standing and ambulation; hospital length of stay; and adverse events. RESULTS: There was no significant difference in the 24-h total morphine consumption (ropivacaine group, median [interquartile range], 13 [7 to 21] versus saline group, 16 [9 to 21] mg; median difference, -1.5; 95% CI, -5 to 2; P = 0.337). Pain scores were not different between the groups (ß = -0.4; 95% CI, -0.9 to 0.2; P = 0.199). There was no statistical difference between the two groups in intraoperative sufentanil consumption, morphine consumption in the postanesthesia care unit, motor blockade, times to first standing (median difference, 0.83 h; 95% CI, -1.7 to 3.4; P = 0.690) and ambulation (median difference, -1.85 h; 95% CI, -4.5 to 0.8; P = 0.173), hospital length of stay, and adverse events. CONCLUSIONS: After elective hip arthroplasty, neither morphine consumption nor pain scores were reduced by the addition of a posterior quadratus lumborum block to a multimodal analgesia regimen.

Real-Time Injection Pressure Sensing and Minimal Intensity Stimulation Combination During Ultrasound-Guided Peripheral Nerve Blocks: An Exploratory Observational Trial.

BACKGROUND: Nerve damage can occur after peripheral nerve block (PNB). Ultrasound guidance does not eliminate the risk of intraneural injection or nerve injury. Combining nerve stimulation and injection pressure (IP) monitoring with ultrasound guidance has been suggested to optimize needle tip location in PNB. In this prospective observational study, we hypothesized that measured pairs of IP and minimum intensity of stimulation (MIS) might differentiate successive needle tip locations established by high-resolution ultrasound during PNB. METHODS: For this exploratory study, 240 observations for 40 ultrasound-guided PNBs were studied in 28 patients scheduled for orthopedic surgery. During the progression of the needle to the nerve observed by ultrasonography, the IP was measured continuously using a computerized pressure-sensing device with a low flow rate of solution. Stimulation thresholds and electrical impedance were obtained by an impedance analyzer coupled to the nerve stimulator at 6 successive needle positions. The median (quartile) or mean (95% confidence interval [CI]) was reported. A mixed model analysis was used, and the sample was also explored using a classification and regression tree (CART) algorithm. RESULTS: Specific combinations of IP and MIS were measured for subcutaneous, epimysium contact, intramuscular, nerve contact (231 mm Hg [203-259 mm Hg] and 1.70 mA [1.38-2.02 mA]), intraneural location (188 mm Hg [152-224 mm Hg] and 0.58 mA [0.46-0.70 mA]), and subparaneural location (47 mm Hg [41-53 mm Hg] and 1.35 mA [1.09-1.61 mA]). The CART algorithm shows that the optimal subparaneural needle tip position might be defined by the lowest pressure (<81.3 mm Hg) and MIS (<1.5 mA) cutoffs. CONCLUSIONS: Our exploratory study evaluated concepts to generate hypotheses. The combinations of IP and MIS might help the physician during a PNB procedure. A low IP and low MIS might confirm a subparaneural location, and a high IP and a low MIS might be an alert for the intraneural location of the needle tip.

Injection pressure monitoring during peripheral nerve blocks: from bench to operating theatre.

BACKGROUND: Nerve damage can occur after ultrasound-guided peripheral nerve block (PNB). Injection pressure monitoring could improve the safety of PNB. The aim was to analyse parameters affecting pressure measurements during PNB. METHODS: The flow characteristics of needles connected to a pressure-sensing device were evaluated. Needles were placed under ultrasound guidance extra or epineurally in nerves/plexus of fresh cadavers. Using three flow rates, 4 mL of saline was injected and plateau pressure was measured. Finally, orthopaedic surgery patients receiving PNB were enrolled for an observational real-time pressure monitoring study. During PNB, periods with pressure > 50 mmHg were noted (high pressure ≥ 750 mmHg). A blinded investigator recorded injection pressure curves and peak pressure. RESULTS: The needle diameter influenced the injection pressure (ß = 66.8; P < 0.0001). Non-echogenic needles increased the injection pressure (ß = 82; P = 0.0009) compared with echogenic needles. Cadaver injection pressure was higher for intraneural (255 [122.5-555] mmHg) versus extraneural needle tip location (90 [50-158] mmHg; P < 0001); for high flow (9.6 mL/min; 470 [265; 900] mmHg) versus low flow (1.2 mL/min; 120 [71-250] mmHg) (P < 0.001) and for cervical roots (900 mmHg, intraneurally) compared with nerves (300 mmHg, intraneurally). In 37 patients and 61 procedures, there were 7 [1-18] peaks of injection pressure per procedure. Pressure was noted > 750 mmHg during 13.80% of the procedural time. CONCLUSIONS: Needle diameter, needle tip location, type of nerve/plexus, flow rates, and the anaesthetist can have a significant effect on injection pressure values and monitoring. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03430453.