Ultrasound imaging for popliteal sciatic nerve block

BACKGROUND AND OBJECTIVES: Ultrasound is a novel method of nerve localization but its use for lower extremity blocks appears limited with only reports for femoral 3-in-1 blocks. We report a case series of popliteal sciatic nerve blocks using ultrasound guidance to illustrate the clinical usefulness of this technology. CASE REPORT: The sciatic nerve was localized in the popliteal fossa by ultrasound imaging in 10 patients using a 4- to 7-MHz probe and the Philips ATL HDI 5000 unit. Ultrasound imaging showed the sciatic nerve anatomy, the point at which it divides, and the spatial relationship between the peroneal and tibial nerves distally. Needle contact with the nerve(s) was further confirmed with nerve stimulation. Circumferential local anesthetic spread within the fascial sheath after injection appears to correlate with rapid onset and completeness of sciatic nerve block. CONCLUSIONS: Our preliminary experience suggests that ultrasound localization of the sciatic nerve in the popliteal fossa is a simple and reliable procedure. It helps guide block needle placement and assess local anesthetic spread pattern at the time of injection.     

A comparison of lateral popliteal versus lateral midfemoral sciatic nerve blockade using ropivacaine 0.5%

BACKGROUND AND OBJECTIVES: The midfemoral approach to the sciatic nerve (MF) is a new technique that has been used for postoperative analgesia after knee surgery. The aim of the present study was to compare efficacy, performance time, and patient acceptance of the midfemoral approach to that of the lateral approach at the level of the popliteal fossa (popliteal block [PB]). METHODS: Sixty-three patients were enrolled in this prospective, randomized study. Thirty-two patients received a lateral sciatic nerve block (group PB) and 31 patients a midfemoral block (group MF). Ropivacaine 0.5% (30 mL) was used in both groups. RESULTS: The quality of nerve blockade was comparable in both groups. Onset of sensory block for peroneal and tibial nerves was significantly shorter in group MF than in group PB, 5 (1-20) minutes and 5 (1-20) minutes versus 10 (1-40) minutes and 10 (1-45) minutes, respectively. Onset of motor block in both territories was also shorter in group MF compared with PB, 6 (2-35) minutes and 5 (2-55) minutes versus 15 (2-60) minutes and 15 (2-60) minutes, respectively (P <.05). There was no difference in duration of sensory and motor blockade, 16 (7-32) hours versus 16 (6-43) hours and 16 (8-32) hours versus 16 (6-25) hours. There was no significant difference between both groups with respect to difficulty of nerve block performance. Patient discomfort during needle puncture was also similar. CONCLUSIONS: The midfemoral approach to the sciatic nerve for ankle and foot surgery resulted in a reliable anesthetic, comparable to that of the lateral popliteal approach. This technique is simple, safe, and provides postoperative analgesia as effective as that obtained with the lateral approach.     

Plantar flexion seems more reliable than dorsiflexion with Labat's sciatic nerve block: a prospective, randomized comparison

Labat's classic approach to the sciatic nerve has not been able to show which motor response of the foot provides a more frequent rate of complete sensory and motor block. In this prospective, randomized, double-blind study, we compared plantar flexion with dorsiflexion with regard to onset time and efficacy of sciatic nerve block using the classic posterior approach. A total of 80 patients undergoing hallux valgus repair were randomly allocated to receive sciatic nerve block after evoked plantar flexion (n=40) or dorsiflexion (n=40). Twenty milliliters of 0.75% ropivacaine was injected after the motor response was elicited at <0.5 mA. Success rate was defined as complete sensory and motor block in all sciatic nerve distributions associated with a pain-free surgery. Time required for onset of sensory and motor block of the foot was recorded. Success was more frequent after elicited plantar flexion (87.5%) than dorsiflexion (55%; P <0.05). Onset of complete sensory and motor block of the foot was faster after elicited plantar flexion (10 +/- 10 min and 13 +/- 10 min, respectively) compared with dorsiflexion (20 +/- 11 min and 24 +/- 12 min; P <0.05). We conclude that plantar flexion of the foot predicts a shorter onset time and a more frequent success rate than dorsiflexion with Labat's classic posterior sciatic nerve block.     

Continuous popliteal sciatic nerve block for postoperative pain control at home: a randomized,double-blinded,placebo-controlled study

BACKGROUND: This randomized, double-blinded, placebo-controlled study investigated the efficacy of patient-controlled regional analgesia using a sciatic perineural catheter in the popliteal fossa and a portable infusion pump for outpatients having moderately painful, lower extremity orthopedic surgery. METHODS: Preoperatively, patients (n = 30) received a sciatic nerve block and perineural catheter in the popliteal fossa. Postoperatively, patients were discharged with both oral opioids and a portable infusion pump delivering study solution (0.2% ropivacaine or 0.9% saline) via the catheter for 3 days. Investigators and patients were blinded to random group assignment. Daily end-points included pain scores, opioid use and side effects, sleep quality, and symptoms of catheter- or local anesthetic-related complications. RESULTS: Ropivacaine (n = 15) infusion significantly reduced pain compared with saline (n = 15) infusion ( < 0.001). For example, the average pain at rest (scale: 0-10) on postoperative day 1 (median, 25th -75th percentile) was 4.0 (3.5-5.5) for the saline group, versus 0.0 (0.0-0.0) for the ropivacaine group (P < 0.001). Oral opioid use and related side effects were significantly decreased in the ropivacaine group. For example, on postoperative day 1, median tablet consumption was 8.0 (5.0-10.0) and 0.0 (0.0-0.0) for the saline and ropivacaine groups, respectively (P < 0.001). Sleep disturbance scores were more than 10-fold greater for saline administration than for ropivacaine infusion (P < 0.001). Overall satisfaction was significantly greater in the ropivacaine group. Other than two inadvertent catheter dislodgements, no catheter- or local anesthetic-related complications occurred. CONCLUSIONS: After moderately painful orthopedic surgery of the lower extremity, ropivacaine infusion using a portable mechanical pump and a popliteal sciatic perineural catheter at home decreased pain, opioid use and related side effects, sleep disturbances, and improved overall satisfaction.     

Continuous epidural block versus continuous popliteal nerve block for postoperative pain relief after major podiatric surgery in children: a prospective, comparative randomized study

Foot and ankle surgery in children is very painful postoperatively. Adverse effects from opioids and continuous epidural block (CEB) limit their use in children. Continuous popliteal nerve blocks (CPNB) have not been studied for this indication in children. In this prospective, randomized study we evaluated the effectiveness and adverse events of CPNB or CEB in children after podiatric surgery. Fifty-two children scheduled for foot surgery were separated into four groups by age and analgesia technique. After general anesthesia, 0.5 to 1 mL/kg of an equal-volume mixture of 0.25% bupivacaine and 1% lidocaine with 1:200000 epinephrine was injected via epidural or popliteal catheters. In the postoperative period, 0.1 mL x kg(-1) x h(-1) (group CPNB) or 0.2 mL x kg(-1) x h(-1) (group CEB) of 0.2% ropivacaine was administered for 48 h. Niflumic acid was routinely used. Adverse events were noted in each treatment group. Postoperative pain during motion was evaluated at 1, 6, 12, 18, 24, 36, and 48 h. Requirement for rescue analgesia (first-line propacetamol 30 mg/kg 4 times daily or second-line 0.2 mg/kg IV nalbuphine), and motor blockade were recorded. Parental satisfaction was noted at 48 h. Twenty-seven patients were included in the CEB groups and 25 in CPNB groups. There were 32 children 1 to 6 yr of age (CPNB = 15; CEB = 17) and 20 children 7 to 12 yr of age (CPNB = 10; CEB = 10). The demographic data were comparable among groups. Postoperative analgesia was excellent for the two continuous block techniques and in the two age groups. Motor block intensity was equal between techniques. Adverse events (postoperative nausea or vomiting, urinary retention, and premature discontinuation of local anesthetic infusion in the 1- to 6-yr-old group) were significantly more frequent in the CEB group (P < 0.05). Eighty-six percent of the parents in the CEB groups and 100% in the CPNB groups were satisfied. We conclude that although both CEB and CPNB resulted in excellent postoperative analgesia in this study, CPNB was associated with less urinary retention and nausea and vomiting. Therefore, we recommend CPNB as the ideal form of postoperative analgesia after major podiatric surgery in 1- to 12-yr-old children.     

Ultrasound guidance for ulnar nerve block in the forearm

OBJECTIVE: The objective of this study was to establish the feasibility of ulnar nerve block under direct imaging. CASE REPORTS: Two patients undergoing surgery on the fifth digit or medial hand received ulnar nerve blocks in the mid-forearm (approximately 15 cm proximal to the styloid process of the ulna). Ultrasound imaging was used to identify the ulnar nerve in the forearm and guide local anesthetic infiltration. Both patients had successful blocks, including sensory anesthesia of the dorsomedial hand. CONCLUSIONS: Ultrasound guidance for ulnar nerve block in the forearm is a promising technique that includes block of the dorsal cutaneous branch. Anatomic and sonographic considerations are discussed.     

Levobupivacaine 0.2% or 0.125% for continuous sciatic nerve block: a prospective, randomized, double-blind comparison with 0.2% ropivacaine

In 60 patients receiving elective hallux valgus repair, we compared the efficacy of continuous popliteal sciatic nerve block produced with 0.2% ropivacaine (n = 20), 0.2% levobupivacaine (n = 20), or 0.125% levobupivacaine (n = 20) infused with a patient-controlled system starting 3 h after a 30-mL bolus of the 0.5% concentration of the study drug and for 48 h (baseline infusion rate, 6 mL/h; incremental dose, 2 mL; lockout time, 15 min; maximum incremental doses per hour, 3). No differences were reported in the intraoperative efficacy of the nerve block. The degree of pain was similar in the three groups throughout the study period, both at rest and during motion. Total consumption of local anesthetic solution during the first 24 h was 148 mL (range, 144-228 mL) with 0.2% ropivacaine, 150 mL (range, 144-200 mL) with 0.2% levobupivacaine, and 148 mL (range, 144-164 mL) with 0.125% levobupivacaine (P = 0.59). The volume of local anesthetic consumed during the second postoperative day was 150 mL (range, 144-164 mL) with 0.2% ropivacaine, 154 mL (range, 144-176 mL) with 0.2% levobupivacaine, and 151 mL (range, 144-216 mL) with 0.125% levobupivacaine (P = 0.14). A smaller proportion of patients receiving 0.2% levobupivacaine showed complete recovery of foot motor function as compared with 0.2% ropivacaine and 0.125% levobupivacaine, both at 24 h (35% vs 85% and 95%; P = 0.0005) and at 48 h (60% vs 100% and 100%; P = 0.001). We conclude that sciatic infusion with both 0.125% and 0.2% levobupivacaine provides adequate postoperative analgesia after hallux valgus repair, clinically similar to that provided by 0.2% ropivacaine; however, the 0.125% concentration is preferred if early mobilization of the operated foot is required.     

Ultrasound vs nerve stimulation multiple injection technique for posterior popliteal sciatic nerve block

In this prospective, randomised, observer-blinded study we evaluated whether ultrasound guidance can shorten the onset time of popliteal sciatic nerve block as compared to nerve stimulation with a multiple injection technique. Forty-four ASA I–III patients undergoing posterior popliteal sciatic nerve block with 20 ml of 0.75% ropivacaine were randomly allocated to nerve stimulation or ultrasound guided nerve block. A blinded observer recorded onset of sensory and motor blocks, success rates, the need for fentanyl intra-operatively, the requirement for general anaesthesia, procedure-related pain, patient satisfaction and side-effects. Onset times for sensory and motor blocks were comparable. The success rate was 100% for ultrasound guided vs 82% for nerve stimulation (p = 0.116). Ultrasound guidance reduced needle redirections (p = 0.01), were associated with less procedural pain (p = 0.002) and required less time to perform (p = 0.002). Ultrasound guidance reduced the time needed for block performance and procedural pain.     

A prospective, randomized comparison between the popliteal and subgluteal approaches for continuous sciatic nerve block with stimulating catheters

In this prospective, blinded study, we randomized 56 patients undergoing hallux valgus repair to receive continuous sciatic nerve block using a subgluteal (n = 28) or a posterior popliteal approach (n = 28) with a perineural stimulating catheter. Postoperatively, the stimulating catheter was connected to a patient-controlled analgesia pump with 0.0625% levobupivacaine (basal infusion rate of 3 mL/h, patient-controlled bolus dose of 3 mL, and lockout time of 20 min). Both approaches provided similar postoperative analgesia; however, local anesthetic consumption was larger in the popliteal group (4.9 +/- 1.4 mL/h) compared with the subgluteal group (3.8 +/- 1.1 mL/h; P < 0.05). We conclude continuous postoperative analgesia using stimulating catheters was effective at both injection sites; however, a subgluteal approach reduced the overall amount of local anesthetic.     

A prospective, randomized comparison between ultrasound and nerve stimulation guidance for multiple injection axillary brachial plexus block

BACKGROUND: This prospective, randomized, blinded study tested the hypothesis that ultrasound guidance can shorten the onset time of axillary brachial plexus block as compared with nerve stimulation guidance when using a multiple injection technique. METHODS: Sixty American Society of Anesthesiology physical status I-III patients receiving axillary brachial plexus block with 20 ml ropivacaine, 0.75%, using a multiple injection technique, were randomly allocated to receive either nerve stimulation (group NS, n = 30), or ultrasound guidance (group US, n = 30) for nerve location. A blinded observer recorded the onset of sensory and motor blocks, the need for general anesthesia (failed block) or greater than 100 microg fentanyl (insufficient block) to complete surgery, procedure-related pain, success rate, and patient satisfaction. RESULTS: The median (range) number of needle passes was 4 (3-8) in group US and 8 (5-13) in group NS (P = 0.002). The onset of sensory block was shorter in group US (14 +/- 6 min) than in group NS (18 +/- 6 min) (P = 0.01), whereas no differences were observed in onset of motor block (24 +/- 8 min in group US and 25 +/- 8 min in group NS; P = 0.33) and readiness to surgery (26 +/- 8 min in group US and 28 +/- 9 min in group NS; P = 0.48). No failed block was reported in either group. Insufficient block was observed in 1 patient (3%) of group US and 2 patients (6%) of group NS (P = 0.61). Procedure-related pain was reported in 6 patients (20%) of group US and 14 patients (48%) of group NS (P = 0.028); patient acceptance was similarly good in the two groups. CONCLUSION: Multiple injection axillary block with ultrasound guidance provided similar success rates and comparable incidence of complication as compared with nerve stimulation guidance.     

Continuous popliteal sciatic nerve block for outpatient foot surgery--a randomized, controlled trial

BACKGROUND: A major problem in outpatient foot surgery is severe postoperative pain that is not sufficiently treated by peroral analgesics. METHODS: Sixty-three patients underwent foot surgery under spinal anesthesia. Immediately on conclusion of the operation, sciatic and saphenous nerve blocks were performed. The sciatic nerve was blocked in the popliteal fossa with 30 ml of ropivacaine 5 mg ml(-1) and a perineural catheter was passed through the cannula. The patients were randomized to receive either ropivacaine 2 mg ml(-1) (n=30) or saline (n=30) in the catheter through a disposable elastomeric pump with a fixed infusion rate of 5 ml h(-1) for 55 h. RESULTS: Analgesia was excellent until 23 h 44 min (14 h 34 min) in the treatment group and 18 h 16 min (7 h) in the placebo group [mean (SD), P=0.07]. Thereafter, pain was significantly less in the treatment group on the first and second postoperative days (P=0.001). Sleep disturbances because of the pain in the foot were experienced by 25% of the treatment group on the first night at home and by 50% of the control group (P=0.29). There were no differences between the groups in their need for rescue opioid medication. None of the patients had any major problem with the catheter or pump, and none had any toxic effect referable to the technique. CONCLUSION: This randomized, double-blind study shows that continuous blockade of the sciatic nerve in the popliteal fossa reduces postoperative pain and has no untoward effects in a patient group known to experience severe pain after ambulatory surgery.