Dislodgment of continuous suprascapular nerve block catheters after physiotherapy: A cadaver study.

BACKGROUND: Continuous peripheral nerve blocks are commonly used for pain management. However, the incidence of catheter dislodgement or migration is unclear, and may be underestimated and underreported. Our objective was to assess suprascapular catheter tip positioning before and after routine simulated shoulder physiotherapy manipulation in an anatomical cadaver model. METHOD: Eight ultrasound-guided continuous suprascapular nerve block catheters were placed in cryopreserved fresh cadavers. Computed tomography (CT) confirmed the location of the catheter tip after injection of 1 ml of contrast medium. We performed a series of standardized shoulder movements during a simulated shoulder physiotherapy session in cadavers. Following this, we administered 1 ml of methylene blue through the catheters, and then performed anatomical dissections to accurately identify the location of the catheter tips and compare them to their placement prior to the 'physiotherapy'. RESULT: CT imaging confirmed the location of the catheter tips at the suprascapular notch in all cases. However, following physiotherapy, 2 catheters (25%) were found to have migrated - specifically, 1 was located in the supraspinatus muscle, and the other was located in the trapezius muscle. CONCLUSION: Our findings suggest that catheter dislodgement may occur in approximately 25% of cases following simulated physiotherapy manipulation. However, further research is needed to determine the read incidence of catheter dislodgement in clinical practice.

Ultrasound-guided genicular nerves block vs. local infiltration analgesia for total knee arthroplasty: a randomised controlled non-inferiority trial.

Genicular nerves block is a promising technique to treat acute postoperative pain in total knee arthroplasty. Similar to surgeon-administered local infiltration analgesia, it targets sensory branches from the knee capsule, but through a selective ultrasound-guided injection that reduces local anaesthetic dose (150 ml ropivacaine 0.2% with local infiltration analgesia vs. 20 ml with genicular nerves block). This randomised non-inferiority trial compared the analgesic efficacy of genicular nerves block vs. local infiltration analgesia in the first 24 h following total knee arthroplasty. Sixty patients were randomly allocated to receive either ultrasound-guided block of five genicular nerves or local infiltration analgesia. The primary outcome was rest pain numeric rating scale (0-10) at 24 h. Secondary outcomes included pain numeric rating scale (rest and movement) and cumulative opioid consumption during the first 24 h. We analysed 29 patients in the genicular nerves block group and 30 in the local infiltration analgesia group. We found that the median difference (95%CI) in postoperative rest pain at 24 h (non-inferiority criteria, Δ = 1) was -1.0 (-2.0 to 1.0, p < 0.001). Median difference in cumulative opioid consumption was 0.0 mg (-3.0-5.0, p < 0.001) meeting the non-inferiority criteria, Δ = 23 mg. We conclude that genicular nerves block of five nerves provides non-inferior analgesia in the first 24 h following surgery compared with local infiltration analgesia, but with a considerable reduction in the local anaesthetic dose.

Perioperative medicine role in painful knee prosthesis prevention.

Total knee arthroplasty is one of the most frequently performed orthopaedic surgeries. However, up to 20% of patients develop persistent postoperative pain. Persistent postoperative pain may be an extension of acute postoperative pain, but can also occur after more than 3 months without symptoms. Risk factors associated with persistent postoperative pain after arthroplasty have now been characterised within the patient's perioperative context (preoperative, intraoperative and postoperative), and can be grouped under genetic, demographic, clinical, surgical, analgesic, inflammatory and psychological factors. Identification and prevention of persistent postoperative pain through a multimodal and biopsychosocial approach is essential in the context of perioperative medicine, and has been shown to prevent or ameliorate postoperative pain.

Perioperative medicine role in painful knee prosthesis prevention. / Papel de la medicina perioperatoria en la prevención de la prótesis de rodilla dolorosa.

Total knee arthroplasty is one of the most frequently performed orthopaedic surgeries. However, up to 20% of patients develop persistent postoperative pain. Persistent postoperative pain may be an extension of acute postoperative pain, but can also occur after more than 3 months without symptoms. Risk factors associated with persistent postoperative pain after arthroplasty have now been characterised within the patient's perioperative context (preoperative, intraoperative and postoperative), and can be grouped under genetic, demographic, clinical, surgical, analgesic, inflammatory and psychological factors. Identification and prevention of persistent postoperative pain through a multimodal and biopsychosocial approach is essential in the context of perioperative medicine, and has been shown to prevent or ameliorate postoperative pain.

Anatomical description of anaesthetic spread after deep erector spinae block at L-4. / Estudio anatómico de la distribución del volumen administrado tras bloqueo en el plano profundo del erector espinal a nivel lumbar.

INTRODUCTION: Thoracic erector spinae plane (ESP) block is now used for postoperative analgesia. However, although reports of lumbar ESP have been published, the anesthetic spread and mechanism of action of this technique remains unclear. We describe the lumbar ESP block technique and evaluate the spread of 20ml of solution administered at the level of the transverse process of L4 in a cadaver model. METHODS: Observational study after 12 lumbar ESP blocks at L4 on a fresh cadaver model (6 bilaterally). The spread of 20ml of injected contrast solution was assessed by computed tomography in all 6 samples. Four of the samples were evaluated by anatomical study, 2 by plane dissection, and 2 others were frozen and cut into 2-2.5cm axial slices. RESULTS: The injected solution spread from L2 to L5 in a cranio-caudal direction in the erector spinae muscle, reaching the facet joints medially and the thoracolumbar fascia laterally. In 33% of cases the solution did not spread anterior to the transverse process; in 51%, spread was minimal and did not affect the corresponding spinal nerves, and in 2 samples (16%), spread was extensive and reached the corresponding spinal nerves. CONCLUSIONS: Lumbar ESP at L4 always acts on the posterior branches of the spinal nerves, but seldom spreads to the paravertebral space to block the spinal nerve.

L4 erector spinal plane block after lumbar spine arthrodesi: A case-series. / Bloqueo del plano del erector espinal en L4 en cirugía de artrodesis lumbar: serie de casos.

INTRODUCTION: Thoracic erector spinae plane block is now performed in many different surgical procedures, including lumbar spinal fusion. We evaluated the analgesic effect of lumbar ESP performed at L4 after lumbar spinal fusion surgery. METHODS AND CASE SERIES: Eight patients scheduled for lumbar spinal fusion were included in the case series. Erector spinae plane block was performed at L4 preoperatively, administering 20ml of 0.2% ropivacaine on each side. We recorded patient-reported pain intensity during the first 48 postoperative hours using a visual analogue scale (VAS) and rescue analgesia requirements. Pain at rest was controlled in all patients (VAS 0 to 3), although pain on movement ranged from mild to severe (VAS 0 to 8). Rescue analgesia consumption ranged from 1 to 22mg morphine. CONCLUSIONS: Lumbar ESP appears to contribute to pain control during the first 48hours after lumbar spinal fusion.

Analgesic efficacy of modified pectoral block plus serratus plane block in breast augmentation surgery: A randomised, controlled, triple-blind clinical trial. / Eficacia analgésica del bloqueo pectoral modificado más bloqueo del plano del serrato en mamoplastia subpectoral: ensayo clínico, controlado, aleatorizado, triple ciego.

INTRODUCTION: Prosthetic breast surgery is a very common plastic surgery procedure, but its postoperative analgesic management is a challenge for the surgical team. The purpose of the present study is to validate the analgesic efficacy of pectoral block and serratus plane block in retropectoral mammoplasty. PATIENTS AND METHODS: A randomised, controlled, triple-blind, clinical trial was designed, and included 30 patients undergoing retropectoral augmentation mammoplasty. All of them had a modified PECII block and a serratus plane block with a total volume of 40ml per breast. In 15 of them bupivacaine 0.25% (GPEC) was injected and in the other 15 patients saline was used (GC). Standardised management of anaesthesia and postoperative analgesia was performed. Intra-operative haemodynamic parameters required for postoperative analgesia, and a numeric verbal scale on arrival in the recovery unit were measured and at 3, 6, and 24h. The quality perceived by patients and surgeons was also measured. RESULTS: Post-operative pain was significantly better in GPEC (5.3±2.3 vs. 2.9±2.7; P=.018). No significant differences were observed at 3, 6, and 24h. The surgeons rated the anaesthetic-analgesic quality as very good in 80% of the cases in GPEC versus 33% in CG (P=.01). CONCLUSIONS: The use of these blocks is a good perioperative analgesic strategy in the multimodal management of retropectoral augmentation mammoplasty.

Cross-sectional area of the median nerve after intraneural vs perineural low volume administration. / Evaluación del área de sección del nervio mediano tras la inyección intraneural o perineural.

INTRODUCTION: To recognise the relationship between the needle tip and the median nerve during peripheral nerve block is of interest to avoid neural damage. However, signs of intraneural injection are not clearly established. The aim of this study was to define the changes observed in the peripheral nerve after the intraneural or perineural administration of 1ml of solution. MATERIAL AND METHODS: Ultrasound guided median nerve blocks were performed in the forearm of 10 fresh cadavers on 60 occasions (3 per forearm). They were randomised into the intraneural (n=30) or perineural (n=30) location of the needle tip, after the consensus of location by 7 specialists. After 1ml of solution was injected an evaluation was made of the changes in the cross-sectional area of the nerve, as well as the displacement along the nerve. RESULTS: The cross-sectional area of the median nerve was increased in both groups, however, the increase was significantly higher in the intraneural group (perineural 0.007±0.013cm2 vs. intraneural 0.032±0.021cm2, P<.0001). An increase of more than 27% of the area ensures an intraneural injection in the median nerve according to the ROC curve analysis. Both proximal and distal diffusion were observed more frequently in the intraneural group (proximal: 86% vs 14%, P<.0001, Distal: 43% vs 4%, P<.0001). CONCLUSIONS: Based on this experimental study, it is concluded that the injection of a small volume (1ml) allows to discriminate the disposition of the intraneural vs perineural needle in a high percentage of cases. Therefore, it is suggested that this "dose test" should be considered in the safety algorithms if it is required to reduce the incidence of intraneural injection.

The effect of the volume of supra-inguinal injected solution on the spread of the injectate under the fascia iliaca: a preliminary study.

The fascia iliaca compartment is the compartment confined by the fascia iliaca (FI) and a muscular layer formed by the iliac- and psoas muscle. This compartment creates a virtual tunnel that contains the femoral nerve (FN), the obturator nerve (ON), and the lateral femoral cutaneous nerve (LFCN) of the lumbar plexus. In this pilot study, we aimed to determine the suggested volume needed to reach the three target nerves of the lumbar plexus (FN, ON, and LFCN) with a single-injection ultrasound-guided supra-inguinal fascia iliaca compartment (S-FICB). A computer tomography (CT scan)-guided step-up/step-down sequence was used to determine the suggested injection volume to target all three nerves. Subsequently, an anatomist blinded for the injected volume and CT findings, dissected the cadavers, and evaluated the spread of dye underneath the fascia iliaca. In total, seven pelvic areas of four cadavers were evaluated on CT scan and dissected. Distribution of dye underneath the FI in relation to the FN, ON, and the LFCN was recorded in all dissected cadavers. Combining CT and dissection findings, the suggested volume to reach the FN, ON, and LFCN with an S-FICB was 40 mL.

Ultrasound measurement of anatomical parameters of the upper airway in adults. / Medición ecográfica de parámetros anatómicos de la vía aérea superior en adultos.

BACKGROUND: Most of the works on ultrasound airway anatomy are limited to a morphological description. A study was conducted in order to provide an objective normal range of measurements. MATERIALS AND METHODS: Observational study to describe the ultrasound characteristics of the upper airway in adults without clinical difficult airway criteria, compared to cadaver dissection anatomical models. RESULTS: The study included 45 volunteers (27 men and 18 women), and 3fresh cadavers. The quality of the examination was very good/good in 93% of the cases. MEASUREMENTS: tracheal diameter (1.3±0.3cm), vocal cord (1.6±0.5cm), cricothyroid membrane (0.94±0.32cm), cricotracheal membrane (0.3±0.09cm), thickness of the muscles in the floor of the mouth (MFM) (1.5±0.26cm), sub-mandibular subcutaneous fat plus MFM (2.11±0.34cm), hyoid-mandible distance (5.35±0.69cm), palate-floor of the mouth distance (4.92±0.5cm), palate-anterior border of the mandible (5.51±0.7cm), and palate-pharynx angle (114±14). Observed differences: Males had a larger tracheal diameter than females (M: 1.4±0.3 vs. F: 1.2±0.2cm, p=0.014). Subject height showed a significant correlation with the tracheal diameter (R: 0.501, p<0.001), as well as the length of the vocal cord (R: 0.363, p=0.016), the thickness of MFM (R=0.299, p=0.046) as well as the hyoid-mandible (R: 0.556; p<0.001) and palate-mandible distances (R: 0.362; p=0.015). CONCLUSIONS: Ultrasound allows the anatomy of upper airway to be evaluated, as well as to calculate distances between the anatomical structures. The study defines these distances in adult volunteers without clinical difficult airway criteria.

Outpatient intravenous multimodal elastomeric pump with methadone in ambulatory surgery. / Analgesia multimodal domiciliaria con metadona en perfusión intravenosa mediante bomba elastomérica en cirugía mayor ambulatoria.

BACKGROUND AND OBJECTIVE: Analgesia in Ambulatory Surgery (AS) needs to evolve in parallel with surgical complexity. We designed a study to try to improve analgesia in painful surgery using an intravenous elastomeric pump. As a novelty, methadone was included. PATIENTS AND METHODS: An observational study, physical status ASA I-II, underwent ambulatory surgeries with moderate-severe postoperative pain. Analgesia was administered for 48h by an intravenous multimodal elastomeric pump (methadone, tramadol, dexketoprofen and ondansetron at low doses). Visual Analogue Scale (VAS) at rest and movement were evaluated at 24 and 48h. Andersen Scale, Lattinen Test, rescue analgesia and side-effects were recorded at 24h after surgery. RESULTS: We included 73 patients: 37% abdominal wall surgery, 30% hemorrhoidectomies and 33% perineal surgery. Median VAS score at rest and movement were 0 and 3 at 24h, and 0 and 2 at 48h. At 24h, Andersen's Scale score was ≤1 in 89%, and Lattinen Test ≤6 in 90% of patients. Rescue medication was administered in 30% of patients. Two patients had vomiting at 24 and 48h. Minor catheter and pump dysfunctions were observed in 8% of patients. CONCLUSIONS: Multimodal analgesia with intravenous methadone administered by elastomeric perfusion at home is effective and safe. However, monitoring is needed to diagnosis dysfunction of devices.

The PECS II block as a major analgesic component for clavicle operations: A description of 7 case reports. / Bloqueo PEC II como componente mayor analgésico para operaciones de clavícula: descripción de 7 casos y revisión de la literatura.

Clavicle fractures correspond to 35% of traumatic fractures of the shoulder girdle. Regional anaesthesia has shown better analgesic results than systemic treatment for perioperative management. Innervation of the clavicle is complex, at present its knowledge raises controversy. The lateral pectoral nerve through the innervating musculature predominantly participates in the lateral and anterior part of the clavicle. The following report of 7 cases describes the effective postoperative analgesia of modified PEC II block in patients with middle third clavicle fracture or acromioclavicular dislocation who underwent a modified PEC II block for postoperative pain management, in the context of a multimodal analgesia. The potential advantage of this management over other analgesic procedures should be evaluated in specific clinical trials.

Diaphragmatic thickness ratio (inspiratory/expiratory) as a diagnostic method of diaphragmatic palsy associated with interescalene block. / La ratio de grosor diafragmático (inspiratorio/espiratorio) como método diagnóstico de parálisis diafragmática asociada al bloqueo interescálenico.

INTRODUCTION: Diaphragmatic paralysis is a side-effect associated with interscalene block. Thickness index of the diaphragm muscle (inspiratory thickness/expiratory thickness) obtained by ultrasound has recently been introduced in clinical practice for diagnosis of diaphragm muscle atrophy. Our objective was to evaluate this index for the diagnosis of acute phrenic paresis associated with interscalene block. PATIENTS AND METHODS: We designed an observational study in 22 patients scheduled for shoulder arthroscopy. Spirometry was performed (criteria of phrenic paresis was a decrease in FVC and FEV1 ≥20%). Ultrasound apposition zone was assessed in anterior axillary line and diaphragmatic displacement was evaluated on inspiration and expiration (number of intercostal spaces; phrenic paresis considered a reduction ≥25%) and thickness of the diaphragm muscle (a phrenic paresis was considered an index <1.2). These determinations were performed before and at 20min after interscalene block at C5-C6 with 20ml of 0.5% ropivacaine. RESULTS: Twenty-one patients (95%) presented phrenic nerve block according to one or more of the methods used. One patient did not show any symptoms or signs suggestive of phrenic paralysis and was excluded. All the patients presented phrenic paresis based on the diaphragmatic thickness index, with the pre-block index being 1.8±0.5 and post-block of 1.05±0.06 (P<0.001). Ninety percent of the patients (19) presented phrenic paresis according to spirometry and all the patients had a reduction in diaphragmatic movement after the block (from 1.9±0.5 intercostal spaces to 0.5±0.3; P<0.001). CONCLUSION: The index of inspiratory / expiratory diaphragmatic thickness at cut-off <1.2 seems to be useful in the diagnosis of phrenic paresis associated with interscalene block. This index does not require a baseline pre-assessment.

Ultrasound-guided genicular nerve block for pain control after total knee replacement: Preliminary case series and technical note. / Bloqueo ecoguiado de los nervios geniculados en el manejo analgésico de la artroplastia de rodilla: descripción de la técnica y resultados clínicos preliminares.

INTRODUCTION: Total knee arthroplasty (TKA) is an operation with moderate to severe postoperative pain. The Fast-Track models employ local infiltration techniques with anaesthetics at high volumes (100-150ml). We proposed a genicular nerve block with low volume of local anaesthetic. The aim of our study is to evaluate the periarticular distribution of these blocks in a fresh cadaver model and to describe the technique in a preliminary group of patients submitted to TKA. MATERIALS AND METHODS: In the anatomical phase, 4 genicular nerves (superior medial, superior lateral, inferior medial and inferior lateral) were blocked with 4ml of local anaesthetic with iodinated contrast and methylene blue in each (16ml in total). It was performed on a fresh cadaver and the distribution of the injected medium was evaluated by means of a CT-scan and coronal anatomical sections on both knees. The clinical phase included 12 patients scheduled for TKA. Ultrasound-guided block of the 4 genicular nerves was performed preoperatively and their clinical efficacy evaluated by assessing pain after the reversal of the spinal block and at 12h after the block. Pain was measured using the numerical scale and the need for rescue analgesia was evaluated. RESULTS: A wide periarticular distribution of contrast was observed by CT-scan, which was later evaluated in the coronal sections. The distribution followed the joint capsule without entering the joint, both in the femur and in the tibia. The pain after the reversal of the subarachnoid block was 2±1, requiring rescue analgesia in 42% of the patients. At 12h, the pain according to the numerical scale was 4±1, 33% required rescue analgesia. CONCLUSION: The administration of 4ml of local anaesthetic at the level of the 4 genicular nerves of the knee produces a wide periarticular distribution. Our preliminary data in a series of 12 patients undergoing TKA seems to be clinically effective. Nevertheless, extensive case series and comparative studies with local infiltration techniques with anaesthetics are needed to support these encouraging results.

Ultrasound-guided approach to nerves (direct vs. tangential) and the incidence of intraneural injection: a cadaveric study.

This study evaluated the incidence of nerve puncture and intraneural injection based on the needle approach to the nerve (direct vs. tangential). Two expert operators in regional anaesthesia performed in-plane ultrasound-guided nerve blocks (n = 158) at different levels of the brachial plexus in cadavers, aiming either directly for the nerve (n = 77) or tangentially inferior to the nerve (n = 81). After reaching the outer limit of the nerve, the needle was intentionally advanced approximately 1 mm in both approaches, and 0.2-0.5 ml of saline was injected. Each operator classified (in real time) the needle tip and injectate as intraneural or not. Video clips showing the final position of the needle and the injection were evaluated in the same manner by seven independent expert observers who were blinded to the aims of this study. In addition, 20 injections were performed with ink for histological evaluation. Intraneural injections of saline were observed by the operator in 58% (45/77) of cases using the direct approach and 12% (10/81) of cases using the tangential approach (p < 0.001). The independent observers agreed with the operator in a substantial number of cases (Cohen's kappa index 0.65). Histological studies showed intraneural spread in 83% (5/6) of cases using the direct approach and in 14% (2/14) of cases using the tangential approach (p = 0.007). No intrafascicular injections were observed. There was good agreement between the operators' assessment and subsequent histological evaluation (Cohen's kappa = 0.89). Simulation of an unintentional/accidental advancement of the needle 'beyond the edge' of the nerve suggests significantly increased risk of epineural perforation and intraneural injection when a direct approach to the nerve is used, compared with a tangential approach.