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.

Enhanced visual acuity with echogenic needles in ultrasound-guided axillary brachial plexus block: a randomized, comparative, observer-blinded study.

BACKGROUND: We prospectively evaluated the effect of insertion angle on the visibility of echogenic and nonechogenic needles in phantoms and in axillary nerve blocks in patients. METHODS: Conventional and echogenic needles were studied in phantoms at insertion angles of 0-30°, 30-45°, and ≥ 45°. Operators rated comfort and image quality during the procedure and experts blinded to the needle groups randomly analyzed videos for tip and shaft visibility, surrounding tissue visibility, sharpness of the needle surface, and percentage of time with the needle completely visible. Patients scheduled for axillary nerve block were prospectively enrolled in the clinical study. Needle insertion angles were 0-30° for the median nerve approach, 30-45° for the radial nerve, and ≥ 45° for the musculocutaneous nerve. The same needle parameters were analyzed during the procedure and on videos. RESULTS: Physician comfort and image quality were significantly better for echogenic needles for phantoms and patients at 30-45° and ≥ 45° insertion angles. Needle tip and shaft visibility at 30-45° and ≥ 45° insertion angles in phantoms and for the musculocutaneous nerve in patients were significantly improved, as well as the percentage with complete needle visualization during the procedure. Tissue visibility and needle sharpness were significantly superior for conventional needles. There were no differences concerning block parameters and adverse events. CONCLUSION: Needles with enhanced echogenicity improved physician comfort, image quality, needle visibility, and visualization time of the needle during ultrasound-guided procedures in phantoms and axillary nerve blocks using insertion angles of 30-45° and ≥ 45°.

[French clinical guidelines for prevention of perianaesthetic dental injuries: long text]. / Bris dentaires périanesthésiques: texte long.

INTRODUCTION: Dental injuries represent the most common claims against the anaesthesiologists. Dental lesions are frequent complications of orotracheal intubation and major causal factors are, firstly, preexisting poor dentition, and, secondly, difficult laryngoscopy and tracheal intubation. The aim of this work was to prioritize propositions for prevention in perianaesthetic dental injury and for care in case of dental trauma. METHOD: A GRADE consensus procedure consisting of three rounds was conducted. A purposively selected heterogeneous panel (n=15) of experts, comprising 10 practitioners in anesthesiology, one practitioner who is jurist and anaesthesiologist, two practitioners in maxillofacial surgery, and two practitioners in dentist surgery. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the board members. The guidelines represent the best current evidence based on literature search and professional opinion. RESULTS: The entire panel completed all three rounds and 31 plus six propositions were written for adult and paediatric clinical practice in anaesthesiology, respectively. The experts highlight the interest of preoperative visit for minimizing dental injuries: the practitioner must identify risk factors for difficult intubation and ventilation, describe precisely patient's preoperative dental condition, including upper incisor most commonly involved teeth in dental trauma. Patients have to be informed by practitioner for risk dental injury and anaesthesiology staff must choose his anesthesia protocol before the induction of intubation narcosis, avoiding insufficient anaesthesia and lack of experience by the anaesthesiologist. The choice of accurate proceeding during laryngoscopy, tracheal intubation and extubation for example, can aid in the prevention of dental injury, reduce the number of claims and the cost of litigation process. DISCUSSION: These guidelines delineate an approach for the prevention of perianaesthetic dental trauma and for the immediate or urgent care in case of perianaesthetic dental injury.

[Peripheral nerve blocks of the face in children]. / Les blocs nerveux périphériques de la face chez l'enfant.

The sensory innervation of the face is provided by the three major nerves, emerging from trigeminal nerve: the ophthalmic, maxillary and mandibular nerve. Nerve blocks of the face or head are not widely used in practice in France. However, regional anaesthesia has shown its value in terms of quality of analgesia and perioperative opioid economy in children and adults. Facial peripheral nerve blocks are divided into two categories: superficial trigeminal nerve blocks and deeper blocks such as the mandibular or suprazygomatic maxillary block. The performance of these blocks is simple provided the usual safety rules are followed. As for other peripheral nerve blocks, ultrasound guidance has shown its interest for the realization of facial nerve blocks to identify anatomical structure and to locate the spread of the injected local anaesthetic.

[A new complication related to prolonged prone position: a masseter muscle haematoma]. / Une complication inédite liée au décubitus ventral prolongé : l'ischémie de compression avec hématome du muscle masséter.

We report a case of a 54-year-old man who underwent an prolonged spinal osteosynthesis complicated by a masseter muscle compressive ischaemia and haematoma in the early postoperative period. A special attention of the body compressive points in particular of the face, in association with an horseshoe's headstall, would have probably lead to avoid this complication in this risk factors patient.

[Strategy of postoperative rehabilitation after femoral neck fracture in elderly patients]. / Stratégie de réhabilitation postopératoire de la fracture du col fémoral.

The femoral neck fracture in elderly patient is an entity that is within the scope of "disease causing a femoral neck fracture". The specific factors for successful management of these elderly patients are centered around patient's comorbidities, specific management in a clinical pathway, and more or less early rehabilitation after surgery. The type of fracture, surgery, specific treatment, early active recovery for the patients lying in bed after surgery optimize the functional outcome at mean term. The improvement of nutritional status, equilibrium for comorbidities and early rehabilitation with walking activities and physiotherapy significantly improve functional outcome at short and medium terms and postoperative mortality. The use of multimodal analgesia and regional analgesia primarily by perioperative continuous femoral nerve blocks also improve the medical prognosis and functional outcome of the patient.

[Ultrasound-guided interscalene block: Influence of anatomic variations in clinical practice]. / Bloc interscalénique échoguidé: variations anatomiques et implication clinique.

OBJECTIVES: This study aimed to evaluate visibility of interscalenic brachial plexus (IBP) variations with ultrasonography (US). Secondary end-point compared success rate of the interscalene block (IB) in shoulder surgery with or without the presence of variation. STUDY DESIGN: Retrospective descriptive study, conducted in two University Departments of Anesthesiology. PATIENTS AND METHODS: One hundred and forty-six (27 volunteers and 46 patients) high-resolution US of interscalene region were reviewed. Single shot IB in 46 patients were analyzed over the first 30 minutes comparing groups with variation or not. RESULTS: Forty-nine percent (71/146) regions presented at least one visible variation by US. Thirty-three percent (48/146) showed an intramuscular passage of a root, 8% (12/146) showed a C5 root ahead of the anterior scalene muscle and 23% (33/146) an artery crossing the roots or trunks. Thirty-seven percent (54/146) presented an artery close to the plexus which could be close to the needle. In the forty-six IB performed, the presence of a variation did not show any difference in the sensitive and motor blocks at the 30th minute (p>0.05). CONCLUSION: The high-resolution cervical US highlights the IBP variations. These variations appear not to have any relevant influence on the performance of the single shot IB.

Regional anaesthesia practice for total knee arthroplasty: French national survey - 2008.

BACKGROUND AND OBJECTIVE: Improved pain management techniques and rehabilitation programs have significantly modified outcome for total knee arthroplasty (TKA). OBJECTIVE: The aim of the survey was to describe the French practice patterns in regional anaesthesia for TKA. METHODS: Twenty-item questionnaires were distributed to units with significant orthopaedic activity across France. The content referred to the type of orthopaedic activity; anaesthetic and analgesic management; preoperative patient information; technical aspects describing regional anaesthesia and postoperative analgesia. RESULTS: Response rate was 54%. Combined general anaesthesia and perineural catheter was the most frequently used anaesthetic technique. Most of respondents used multimodal analgesia (including femoral nerve catheter by 80%). Written hygiene protocols were rarely available. Sterile gowns were seldom worn. Among antiseptic agents, povidone iodine was most often used. Sedative agents were systematically used by 36% of respondents. Ropivacaine was the preferred local anaesthetic agent. Finally, adjuvants were rarely used. In most cases (58%) the femoral block was performed before induction of general anaesthesia. The catheter was commonly threaded to a length between 5 and 8 cm. The correct position of the catheter tip was verified clinically by majority of respondents. Local anaesthetics were administered by continuous infusion, continuous infusion plus boluses and boluses alone in 44, 36 and 8% of cases. Catheter duration was 48 and 72 h in 45 and 33% of the units and was independent of pain scores. CONCLUSION: This national survey showed practices in accordance with recent guidelines as well as persistent challenges in regional anaesthesia for TKA.

How and why to use ultrasound for regional blockade.

The practice of regional anaesthesia will be probably forever changed by the introduction of ultrasonography into everyday clinical practice. The ability to now visualise directly the spread of local anaesthetic solution and its relationship with the nerve allows for immediate adjustments to needle position and/or local anaesthetic volume and spread resulting theoratically in improved block performance through faster onset, reduced local anaesthetic volumes and higher success rates. However, whether US guided blocks will ever replace neurostimulation techniques is debatable especially when regional anaesthesia is performed by specialists in the field.

[Electrical nerve localization: non-linear relationship between intensity and pulse duration to stimulate a nerve]. / Neurostimulation: relation non linéaire entre intensité et durée pour stimuler un nerf.

OBJECTIVE: When performing a peripheral nerve block, the current allowing local anaesthetic injection is between 0.3 and 0.5 mA. It has never been assessed if such a threshold remains the same whatever be the pulse duration. The aim of this study was to determine the minimal current required to stimulate a nerve while different pulse durations were applied, and to evaluate the importance of the placement of the cutaneous electrode. STUDY DESIGN: Prospective study. PATIENTS AND METHODS: One hundred and twenty posterior popliteal sciatic (S), femoral (F), or median (M) nerve blocks performed with a nerve stimulator were included. The minimal current for a clearly visible motor response of the corresponding muscle was recorded with a pulse duration set at 50, 150 and 300 micros. The same procedure was repeated with the electrode sited on the controlateral side, before injection of local anaesthetic. RESULTS: The mean lowest charge of current required to stimulate a nerve was 24+/-8 nC at 50 micros. At 150 and 300 micros, it has to be increased by 175 % (42+/-14 nC) and 280 % (67+/-23 nC), respectively. No significant difference in the charge required was noted either among S, F, or M, or by changing the cutaneous electrode position. Adequate anaesthesia was noted in all cases. CONCLUSION: The relationship between intensity and pulse duration is not linear. Moreover, a low charge of current does not seem to be appropriate with pulse duration equal or superior to 300 micros. The location of the cutaneous electrode does not seem to be important.

[Electrical failure with nerve stimulation: cases report and check list for prevention]. / Défaut de circuit électrique et neurostimulation: cas cliniques et procédure de prévention.

Functionality of the nerve stimulator and integrity of the electrical circuit should be verified and confirmed before performing peripheral nerve blockade. The clinical cases reported here demonstrate that electrical disconnection or malfunction during nerve localization can unpredictably occur and a checklist is described to prevent the unknown electrical circuit failure.

[1% mepivacaine and axillary block: duration of the sensory and motor blockade]. / Mépivacaïne à 1% et bloc axillaire: durée du bloc sensitif et moteur.

OBJECTIVES: To assess the duration of both sensory and motor blockade of brachial plexus with 40 mL 1% mepivacaine after axillary or midhumeral approach. STUDY DESIGN: Prospective, open, non-comparative, multicentric study. PATIENTS: One hundred and eighty patients, ASA physical class 1 and 2, scheduled for hand or forearm surgery under brachial plexus block were included. METHODS: A midhumeral or axillary brachial plexus block using a nerve stimulator was performed with 40 mL of 1% mepivacaine. Sensory blockade was tested for each cutaneous area (median, radial, ulnar, musculocutaneous and medial cutaneous nerve of the forearm) using pin-prick. Motor blockade was assessed by grip strength of the hand. Incidence and duration of analgesia, anaesthesia and motor blockade were assessed. The incidence of tourniquet pain and the time when pain occurred were determined. RESULTS: According to the nerve area tested, analgesia and anaesthesia were obtained in 98% and 85% of cases respectively; duration of anaesthesia was between 150 +/- 40 to 167 +/- 49 minutes and duration of analgesia was from 184 +/- 50 to 205 +/- 51 minutes. Duration of paralysis was 144 +/- 40 minutes and duration of paresis was 190 +/- 51 minutes. Pain occurred in three out of 138 patients at tourniquet inflation and in six patients after completion of surgery. CONCLUSIONS: Mid humeral or axillary block with 40 mL of 1% mepivacaine is highly successful and provides efficient surgical anaesthesia for various surgical procedures of intermediary duration.

[Subarachnoid hematoma after spinal anesthesia and low molecular weight heparin]. / Hématome sous-arachnoïdien après rachianesthésie et héparine de bas poids moléculaire.

A case is reported of spinal subarachnoid haematoma occurring after spinal anaesthesia. The patient was given prophylactic pre and postoperative low molecular weight heparin. On the second postoperative day, he complained of backache and got a partial cauda equina syndrome. Magnetic resonance imaging carried out on the 6th day confirmed the presence of a spinal haematoma, which was removed surgically. One year later, the bilateral motor palsy which had involved several roots, had completely regressed. It remained a severe sensory loss associated with a loss of sphincter control. This case highlights the role of predisposing factors and the importance of early diagnosis.