Popliteal Sciatic Nerve Block Research Articles

Ultrasound-Guided Popliteal Sciatic Nerve Block for an Ankle Laceration in a Pediatric Emergency Department

Although ultrasound-guided peripheral nerve block has recently been introduced into pediatric emergency departments, knowledge of its use is limited. We present here a case demonstrating the safety and effectiveness of ultrasound-guided popliteal sciatic nerve block for a pediatric spoke injury in a pediatric emergency department setting.

Does Combination Therapy of Popliteal Sciatic Nerve Block and Adductor Canal Block Effectively Control Early Postoperative Pain after Total Knee Arthroplasty?

PurposeWe compared adductor canal block (ACB) alone and a combination of ACB and sciatic nerve block (SNB) to control early postoperative pain after total knee arthroplasty.Materials and MethodsOne hundred patients received continuous ACB alone (group A), and another 100 patients received continuous ACB and single popliteal SNB (group B). Pain was evaluated at rest and 45° knee flexion using the numeric rating scale (NRS). The number of times the patient pressed the intravenous patient-controlled analgesia (PCA) button, total PCA volume infused, and the total dosage of additional analgesics were evaluated. We also investigated complications associated with each pain control technique.ResultsThe NRS score on postoperative day 1 was significantly lower in group B than in group A. The number of times patients pressed the PCA button on postoperative day 1 and the total infused volume were significantly lower in group B than in group A. Thirty-five (35%) patients in group B developed foot drop immediately after surgery; but they all fully recovered on postoperative day 1.ConclusionsSNB can be effective for management of early postoperative pain that persists even after ACB. Further research is needed to determine the proper dosage and technique for reducing the incidence of foot drop.

Ultrasound-Guided Popliteal Sciatic Block Provides Adequate Analgesia During Urgent Endovascular Treatment of Critical Limb Ischemia with Resting Pain.

To demonstrate feasibility and safety of ultrasound-guided popliteal sciatic nerve block for providing analgesia during urgent endovascular treatment of critical limb ischemia with resting pain. Ultrasound-guided popliteal sciatic blocks were performed by an interventional radiologist in angiography suite immediately prior to commencement of urgent endovascular treatment of 30 critical limb ischemia patients. Subjective pain levels prior to and following sciatic block were assessed using the visual analog scale (VAS). Need for any supplemental anxiolytics or analgesics during treatment was recorded. Post-procedural evaluation of patient and operator satisfaction levels regarding the intervention was also documented. Ultrasound-guided sciatic block provided adequate analgesia in all patients; VAS scores were 0 (no pain) in 87% and 1-3 (mild to annoying pain) in 13%. Two patients required anxiolytic premedication. Additional analgesia was not required during course of endovascular treatment of any patients. Time necessary to perform sciatic block ranged 3-9 (mean 5.9±1.3) min. Median number of needle attempts was 1 (range 1-3). Onset of satisfactory block ranged from 5 to 20min (mean 9.4±2.6min). Mean treatment time was 102.2±36.7min, and balloon time was 22.4±6.1min. Patient and operator satisfaction with pain control were very good in all cases. There were no procedure-related complications. Ultrasound-guided popliteal sciatic block is a feasible and safe alternative for providing adequate analgesia during urgent endovascular treatment of critical limb ischemia with resting pain. Level 4, case series.

Two different placement paths in popliteal fossa with a novel nerve block needle for postoperative analgesia after foot and ankle surgery.

Previous studies have documented that single injection nearby the sciatic nerve bifurcation would influence the anesthesia and analgesia effect. But this is uncertain for preoperative continuous popliteal sciatic nerve block. This trial was conducted to compare two paths (proximal to the bifurcation and at the bifurcation) of ultrasound-guided continuous popliteal sciatic nerve block in foot and ankle surgery. Forty recruited objects were randomly assigned to receive ultrasound-guided continuous popliteal sciatic nerve block at the puncture path proximal to the nerve bifurcation either at the nerve bifurcation. Subjects received an injection using a novel nerve block needle with external indwelling cannula guided by ultrasound invented by the corresponding author. The external indwelling cannula was inserted for postoperative analgesia. The primary outcome was NRS scores (at rest and during movement) times at 24 hours after surgery. The secondary outcomes included the measurements related to the performance of the nerve block and efficacy of analgesia, such as anesthesia effect grade, grade of nausea and vomiting, case number of patients with cannula leaking, occlusion or slipping, patient satisfaction, etc. RESULTS: During the surgery, six subjects in the proximal group needed additional analgesic, significantly different from one in the at bifurcation group (P<0.05). There was significant difference on anesthesia effect rating, 1.6±0.8 in the proximal group and 1.1±0.4 in another (P<0.05). The proximal group got 2.1±1.6 of NRS on rest at 24 hours and 1.7±1.5 at 48 hours, and the at bifurcation group got 0.9±1.4 at 24 hours and 0.7±1.1 at 48 hours (P<0.05). The proximal group got more PCA times during 6-24 hours and 24-48 hours and lower satisfaction scores. Continuous popliteal sciatic nerve block at nerve bifurcation could receive better analgesia effect and more patients' satisfaction, rather than proximal to the bifurcation.

Liposomal Bupivacaine versus Continuous Popliteal Nerve Block in Total Ankle Arthroplasty

Category: Ankle, Ankle Arthritis Introduction/Purpose: The use of liposomal bupivacaine (LB) has recently gained popularity in joint arthroplasty. Despite it’s proven safety and efficacy, there is little reported on the use of LB in foot and ankle surgery. Catheter placement for a continuous popliteal sciatic nerve block (CPSNB) has an excellent track record for pain relief, and is commonly used by our group for major foot and ankle reconstructions. The purpose of this study was to compare the use of intraoperative LB injection to CPSNB as a regional anesthetic for total ankle arthroplasty (TAA), with attention to postoperative pain scores, narcotic use, and complications. Methods: Retrospective review of TAA patients treated by two fellowship-trained orthopedic foot and ankle surgeons was performed. Patient demographic data, operative, and postoperative details were collected, including type of regional anesthetic used. Patient’s received either preoperative single-shot popliteal sciatic nerve block with 0.25% bupivacaine followed by intraoperative injection of LB, or preoperative CPSNB alone. Outcomes examined were VAS pain score at 8 hours, 24 hours, 1 week, and 3 weeks following surgery, need for opioid pain medication refill, physician office notification for pain issues or other adverse events, and complications within the first 90 days following surgery. Standard statistical analysis was performed and p &lt; 0.05 was considered significant. Results: 75 patients were identified who underwent TAA and met inclusion criteria. 41 received LB and 34 received CPSNB. No statistical difference was seen between groups with regard to complications, emergency department visits, readmissions, reoperations, VAS pain score at any time point, physician office contacts, and narcotic refills. Mean VAS with LB use was 1.8, 3.5, 2.6, and 2.2 at 8 hours, 24 hours, 1 week, and 3 weeks respectively, compared with mean VAS 2.1, 3.2, 2.2, and 1.9 at similar time points for CPSNB (p=0.59, 0.65, 0.27, and 0.40, respectively). 16 of 41 LB patients needed narcotic refills, versus 12 of 34 CPSNB patients (p=0.81). 3 of 41 LB patients had a complication postoperatively, versus 4 of 34 CPSNB patients. Conclusion: This is the first study evaluating the use of LB for total ankle arthroplasty. LB was both safe and effective for postoperative pain control, with comparable results to CPSNB. As LB gains more widespread use in foot and ankle surgery, further investigation is warranted to determine potential unseen complications and cost-effectiveness.

Is combination of popliteal sciatic nerve block and adductor canal block effective for postoperative pain control after TKA?

Is combination of popliteal sciatic nerve block and adductor canal block effective for postoperative pain control after TKA?

Analgesic effect of perineural magnesium sulphate for sciatic nerve block for diabetic toe amputation: A randomized trial.

Background and objectivesHigh concentrations of local anesthetics may be neurotoxic for diabetic patients. Additive perineural administration of magnesium was reported to decrease the consumption of local anesthetics for nerve block. It was hypothesized that MgSO4 added to dilute ropivacaine was equianalgesic to more concentrated ropivacaine for toe amputations in diabetic patients.MethodsSeventy diabetic patients were allocated into 3 groups: 1) perineural 200 mg MgSO4 added to 0.25% ropivacaine, 2) 0.25% ropivacaine alone, and 3) 0.375% ropivacaine alone. All patients underwent popliteal sciatic nerve block that was guided by ultrasonography using the respective regimens. Time of onset, duration of motor and sensory block were recorded. Spontaneous and evoked pain score, worst pain score, additional analgesic consumption, satisfaction score and initial time of analgesic requirement of each patient were documented up to 48 hours postoperatively.ResultsIn comparison with 0.25% ropivacaine alone, magnesium supplement prolonged the duration of sensory block (p = 0.001), as well as better evoked pain score at 6 hour postoperatively (p = 0.001). In comparison with evoked pain score (1.6/10) in group of 0.375% ropivacaine, magnesium plus 0.25% ropivacaine presented a little higher score (2.5/10) at 6 hour postoperatively (p = 0.001), while lower worst pain score (p = 0.001) and less postoperative total analgesic consumption (p = 0.002).ConclusionsThe regimen of adding 200mg MgSO4 to 0.25% ropivacaine for sciatic nerve block yields equal analgesic effect in comparison with 0.375% ropivacaine. These findings have suggested that supplemental MgSO4 could not improve analgesic quality except reducing the total amount of local anesthetics requirement in diabetic toe amputations with sciatic nerve blocks.

Effect of Nerve Stimulation Use on the Success Rate of Ultrasound-Guided Subsartorial Saphenous Nerve Block: A Randomized Controlled Trial.

Ultrasound-guided subsartorial saphenous nerve block is commonly used to provide complete surgical anesthesia of the foot and ankle in combination with a popliteal sciatic nerve block. However, in part owing to its small caliber and absence of a prominent vascular landmark in the subsartorial plane distal to the adductor canal, the saphenous nerve is more difficult to reliably block than the sciatic nerve in the popliteal fossa. Although the saphenous nerve is a sensory nerve only, neurostimulation can be used to elicit a "tapping" sensation on the anteromedial aspect of the lower leg extending toward the medial malleolus. Our objective was to test the hypothesis that the addition of nerve stimulation use to an ultrasound (US)-guided technique will increase the success rate of subsartorial saphenous nerve block. With institutional human ethics board approval and participants' written informed consent, we enrolled 80 patients undergoing foot and ankle surgery in a randomized, single-blinded, parallel-group clinical trial. Patients were randomly assigned to receive US-guided subsartorial saphenous nerve block either alone (US group) or with the use of additional nerve stimulation (NS group; time limit, 5 minutes). For saphenous nerve blockade, all patients received 10 mL of 0.5% ropivacaine. The primary end point was complete absence of sensation to pinprick at 30 minutes at two different anatomic areas in the distribution of the saphenous nerve (2 cm proximal to the medial malleolus and 10 cm distal to the medial tibial condyle). Secondary end points included decreased sensation at 30 minutes and block failure (normal sensation) at 30 minutes. This trial was registered at ClinicalTrials.gov: NCT02382744. All 80 patients completed the trial (40 patients in each group). Twenty-two patients (55%) in the NS group versus 18 (45%) in the US group had complete absence of sensation to pinprick at 30 minutes at both anatomic areas of assessment (Fisher exact test, P = 0.25 [one sided]; 95% confidence interval of difference in proportions, -11.9% to 31.9%). The percentages of patients with any evidence of block (decreased or complete absence of sensation) at both areas at 30 minutes were 92.5% (NS) and 97.5% (US), respectively (P = 0.62 [two sided]); corresponding failure rates (normal sensation) were 7.5% (NS) and 2.5% (US). In the NS group, no response in the saphenous nerve distribution was elicited within 5 minutes of stimulation time limit in 20% of patients (n = 8). All of the patients in the NS group with normal sensation at 30 minutes (n = 3) were among this subcohort. The addition of the use of nerve stimulation did not improve the success rate of US-guided subsartorial saphenous nerve block. However, in the NS group, an inability to elicit a "tapping" sensation in the saphenous nerve distribution was associated with block failure.

The effect of obesity on the anatomical relationship of the popliteal artery and tibial nerve in the proximal and distal popliteal fossa: relevance to popliteal sciatic nerve block and a traceback technique using the popliteal artery

Study ObjectiveTo determine the effect of body mass index (BMI) on the relationship of the popliteal artery to the sciatic and tibial nerves in the popliteal fossa. DesignProspective, observational study. SettingUniversity medical center. SubjectsOne hundred patients scheduled for magnetic resonance imaging scans of the knee. MeasurementsBMI was recorded and magnetic resonance imaging scans were assessed at 3 different measurement points along the femur for the distance and angle between the popliteal artery and tibial nerve, or sciatic nerve if the sciatic nerve had not bifurcated at the measurement point. Main ResultsAt the distal femur, the tibial nerve was a mean of 2.9 mm from the popliteal artery. The nerve was consistently posterior to the artery; however, it was variably located medial or lateral to the artery. At the 5- and 8-cm measurement points, the nerve was 10.0 and 16.1 mm (SD, 4.1 and 5.2 mm), and 31° and 44° (SD, 15° and 16°) lateral to the popliteal artery, respectively. Zero degree was defined as directly posterior to the artery. Increasing BMI was correlated with increasing distance between the nerve and the artery at the 5- and 8-cm measurement points (r= 0.36 P> |t| .000 and .45 P> |t| .002). ConclusionsAt 5 cm proximal to the distal femoral condyles, the popliteal artery is a reliable sonographic landmark to locate the tibial nerve due to the close proximity and consistent location of the nerve 1 cm posterolateral to the artery, with only a moderate effect of BMI.

Continuous Popliteal Sciatic Blocks: Does Varying Perineural Catheter Location Relative to the Sciatic Bifurcation Influence Block Effects? A Dual-Center, Randomized, Subject-Masked, Controlled Clinical Trial

Multiple studies have demonstrated that, for single-injection popliteal sciatic nerve blocks, block characteristics are dependent upon local anesthetic injection relative to the sciatic nerve bifurcation. In contrast, this relation remains unexamined for continuous popliteal sciatic nerve blocks. We, therefore, tested the hypothesis that postoperative analgesia is improved with the perineural catheter tip at the level of the bifurcation compared with 5 cm proximal to the bifurcation. Preoperatively, subjects having moderately painful foot or ankle surgery were randomly assigned to receive an ultrasound-guided subepimyseal perineural catheter inserted either at or 5 cm proximal to the sciatic nerve bifurcation. Subjects received a single injection of mepivacaine 1.5% either via the insertion needle preoperatively or the perineural catheter postoperatively, followed by an infusion of ropivacaine 0.2% (6 mL/h basal, 4 mL bolus, and 30-min lockout) for the study duration. The primary end point was the average pain measured on a numeric rating scale (0-10) in the 3 hours before a data collection telephone call the morning after surgery. The average numeric rating scale of subjects with a catheter inserted at the sciatic nerve bifurcation (n = 64) was a median (10th, 25th to 75th, and 90th quartiles) of 3.0 (0.0, 2.4-5.0, and 7.0) vs 2.0 (0.0, 1.0-4.0, and 5.0) for subjects with a catheter inserted proximal to the bifurcation (n = 64; P = 0.008). Similarly, maximum pain scores were greater in the group at the bifurcation: 6.0 (3.0, 4.4-8.0, and 9.0) vs 5.0 (0.0, 3.0-8.0, and 10.0) (P = 0.019). Differences between the groups for catheter insertion time, opioid rescue dose, degree of numbness in the foot/toes, catheter dislodgement, and fluid leakage did not reach statistical significance. For continuous popliteal sciatic nerve blocks, a catheter inserted 5 cm proximal to the sciatic nerve bifurcation provides superior postoperative analgesia in subjects having moderately painful foot or ankle surgery compared with catheters located at the bifurcation. This is in marked contrast with single-injection popliteal sciatic nerve blocks for which benefits are afforded to local anesthetic injection distal, rather than proximal, to the bifurcation.

Diabetic neuropathy increases stimulation threshold during popliteal sciatic nerve block

BackgroundPeripheral nerve stimulation is commonly used for nerve localization in regional anaesthesia, but recommended stimulation currents of 0.3–0.5 mA do not reliably produce motor activity in the absence of intraneural needle placement. As this may be particularly true in patients with diabetic neuropathy, we examined the stimulation threshold in patients with and without diabetes. MethodsPreoperative evaluation included a neurological exam and electroneurography. During ultrasound-guided popliteal sciatic nerve block, we measured the current required to produce motor activity for the tibial and common peroneal nerve in diabetic and non-diabetic patients. Proximity to the nerve was evaluated post-hoc using ultrasound imaging. ResultsAverage stimulation currents did not differ between diabetic (n+55) and non-diabetic patients (n+52). Although the planned number of patients was not reached, the power goal for the mean stimulation current was met. Subjects with diminished pressure perception showed increased thresholds for the common peroneal nerve (median 1.30 vs. 0.57 mA in subjects with normal perception, P+0.042), as did subjects with decreased pain sensation (1.60 vs. 0.50 mA in subjects with normal sensation, P+0.038). Slowed ulnar nerve conduction velocity predicted elevated mean stimulation current (r+−0.35, P+0.002). Finally, 15 diabetic patients required more than 0.5 mA to evoke a motor response, despite intraneural needle placement (n+4), or required currents ≥2 mA despite needle-nerve contact, vs three such patients (1 intraneural, 2 with ≥2 mA) among non-diabetic patients (P+0.003). ConclusionsThese findings suggest that stimulation thresholds of 0.3–0.5 mA may not reliably determine close needle-nerve contact during popliteal sciatic nerve block, particularly in patients with diabetic neuropathy. Clinical trial registrationNCT01488474

Reliability of the direct observation of procedural skills assessment tool for ultrasound-guided regional anaesthesia.

The Direct Observation of Procedural Skills (DOPS) form is used as a workplace-based assessment tool in the current Australian and New Zealand College of Anaesthetists curriculum. The objective of this study was to evaluate the reliability of DOPS when used to score trainees performing ultrasound-guided regional anaesthesia. Reliability of an assessment tool is defined as the reproducibility of scores given by different assessors viewing the same trainee. Forty-nine anaesthetists were recruited to score two scripted videos of trainees performing a popliteal sciatic nerve block and an axillary brachial plexus block. Reliability, as measured by intraclass correlation coefficients, was -0.01 to 0.43 for the individual items in DOPS, and 0.15 for the 'Overall Performance for this Procedure' item. Assessors demonstrated consistency of scoring within DOPS, with significant correlation of sum of individual item scores with the 'Overall Performance for this Procedure' item (r=0.78 to 0.80, P<0.001), and with yes versus no responses to the 'Was the procedure completed satisfactorily?' item (W=24, P=0.0004, Video 1, and W=65, P=0.003, Video 2). While DOPS demonstrated a good degree of internal consistency in this setting, inter-rater reliability did not reach levels generally recommended for formative assessment tools. Feasibility of the form could be improved by removing the 'Was the procedure completed satisfactorily?' item without loss of information.

Workup and Management of Persistent Neuralgia following Nerve Block.

Neurological injuries following peripheral nerve blocks are a relatively rare yet potentially devastating complication depending on the type of lesion, affected extremity, and duration of symptoms. Medical management continues to be the treatment modality of choice with multimodal nonopioid analgesics as the cornerstone of this therapy. We report the case of a 28-year-old man who developed a clinical common peroneal and lateral sural cutaneous neuropathy following an uncomplicated popliteal sciatic nerve block. Workup with electrodiagnostic studies and magnetic resonance neurography revealed injury to both the femoral and sciatic nerves. Diagnostic studies and potential mechanisms for nerve injury are discussed.

Comparison Between Ultrasonography-Guided Popliteal Sciatic Nerve Block and Spinal Anesthesia for Hallux Valgus Repair.

We aimed to compare the efficacy, postoperative pain scores, adverse effects, additional analgesic requirements, and patient satisfaction scores of ultrasonography-guided sciatic nerve block by popliteal approach with spinal anesthesia for hallux valgus correction surgery. Sixty patients scheduled for hallux valgus correction surgery were enrolled in this prospective randomized study. Unilateral spinal block was performed on patients in the spinal anesthesia group. Popliteal block group patients received popliteal sciatic nerve block with guidance by both nerve stimulator and ultrasonography. Durations of anesthetic and operative interventions and time until the initiation of surgery were recorded for both groups. Pain magnitude of the patients at the 2nd, 4th, 6th, 12th, and 24th hours following anesthetic interventions were assessed with a visual analog scale (VAS). Adverse effects such as postoperative urinary retention and postdural puncture headache were recorded. Also, patient satisfaction was recorded. Patients were interviewed by phone for anesthetic and operative complications at 72 hours postoperatively. Spinal anesthesia group patients exhibited hypotension, bradycardia, postdural puncture headache, and urinary retention rates of 6.6%, 3.3%, 10%, and 3.3%, respectively. Popliteal block group patients showed none of these adverse effects. Moreover, VAS scores of the patients at the 2nd, 4th, 6th, and 12th hours were significantly lower (P < .001, P = .003, P < .001, P <.001, respectively), postoperative first analgesic requirement times were significantly longer (P < .001), and pain satisfaction scores were significantly higher (P < .001) in the popliteal block group. Given the complications related to spinal anesthesia and its insufficiency to maintain analgesia postoperatively, we believe the preferred anesthetic method should be peripheral nerve blocks for hallux valgus correction surgeries. Level I, randomized prospective study.

The Popliteal Nerve Block in Foot and Ankle Surgery: an Efficient and Anatomical Technique

The popliteal sciatic nerve block is a form of regional anesthesia most commonly used as a form of postoperative analgesia. It has shown to be effective for 15-20 hours postoperatively. It can also be used for various foot and ankle pathologies including fracture and dislocation reduction, exploration of foreign bodies, and bedside incision and drainage. The popliteal sciatic nerve block has an additional benefit in that it decreases amount of postoperative opioid consumption limiting the complications of these medications. There are several techniques in administering this form of anesthesia including a posterior approach for prone patients, or a lateral approach for a supine patient which requires less time. It is physician preference whether the use of single or double injection technique is employed; however, ultrasound guidance and neurostimulation are typically utilized during this procedure. When using neurostimulation, a plantarflexion response is more predictive of complete sensory blockade than a dorsiflexion response. Using ultrasound with neurostimulation has greater efficacy at 60 minutes than using neurostimualtion alone. While this article’s primary purpose is to review the current literature regarding the popliteal sciatic nerve block, the technique employed at our institution is described. Our technique utilizes a lateral approach in the operating room following induction of general anesthesia. Both ultrasound guidance and neurostimulation are used. An assistant holds the leg with the hip slightly flexed and the knee extended to allow for a taut neurovascular bundle. The approach is approximately 5-7 cm cranial to the lateral femoral condyle at a groove between the anterior border of the biceps femoris tendon and the vastus lateralis muscle. The neurostimulation device is set a 1.0 mA and is advanced until a plantarflexion response is noted. A total of 20-30 cc of 0.5% bupivacaine with epinephrine 1:200,000 is injected. The saphenous nerve can be anesthetized between the sartorius and vastus medialis muscles just anterior to the femoral artery. A combination of the popliteal sciatic nerve block and saphenous nerve block has shown to be efficacious in patient satisfaction and pain relief for 24 hours.

Ultrasound-guided femoral and popliteal sciatic nerve blocks for below knee surgery in patients with severe cardiac disease.

Patients with dilated cardiomyopathy or acute myocardial infarction are at risk of anesthesia complications, and peripheral nerve blocks (PNBs) provide more stable operative hemodynamics than general anesthesia or central neuraxial blocks. We present two rare cases of patients with dilated cardiomyopathy or acute myocardial infarction and a coagulation abnormality that were administered ultrasound-guided femoral and popliteal sciatic nerve blocks as anesthesia for lower limb surgery. A 71-year-old woman (155 cm, 44 kg, ASA 4) was scheduled to undergo open reduction and internal fixation due to a left lateral malleolus fracture. Five year previously, she underwent cardioversion and atrial ablation due to atrial fibrillation and ventricular tachycardia, and was being medicated for liver cirrhosis and dilated cardiomyopathy. Preoperative 2-dimensional electrocardiography showed atrial fibrillation and a left ventricular ejection fraction of 20–25%. Her pulmonary arterial pressure was 30 mmHg. Clopidogrel (75 mg) was maintained during the perioperative period to prevent a thromboembolic event. Prothrombin time international normalized ratio (PT INR) was 1.36, prothrombin time (%) was 64%, and aPTT was 36.6 sec. Ultrasound-guided femoral and popliteal sciatic nerve blocks were chosen due to the risks posed by general anesthesia and a central neuraxial blockade. For the femoral nerve blockade, the patient was placed in the supine position and a linear 6–13 MHz probe (SonoSite M-Turbo ® , SonoSite Bothell, WA, USA) was positioned at left inguinal crease level. Subsequently, after penetrating the fascia iliaca, a 22-gauge 50 mm insulated needle was inserted using the in-plane approach near the femoral nerve (Fig. 1A). After obtaining quadriceps femoris muscle contrac

Minimum effective anaesthetic volume of 0.5% ropivacaine for ultrasound-guided popliteal sciatic nerve block in patients undergoing foot and ankle surgery: determination of ED50 and ED95.

Compared to nerve stimulation or classic paraesthesia techniques, ultrasound (US)-guided popliteal sciatic nerve block requires a smaller volume of local anaesthetic. The up-and-down method was used to determine the minimum effective anaesthetic volume of 0.5% ropivacaine necessary for US-guided popliteal sciatic nerve block to achieve successful surgical anaesthesia for foot and ankle surgery. The study included 32 patients receiving an US-guided popliteal sciatic nerve bock. The starting dose of 0.5% ropivacaine was set at 30 ml, which was decreased by 3 ml if the block succeeded and increased by 3 ml if the block failed. After the injection of local anaesthetic, the degree of sensory and motor blockade of the tibial and common peroneal nerves was assessed every 5 minutes for 30 minutes. The ED50 and ED95 volumes of local anaesthetic were 6 ml and 16 ml, respectively. The success rates of sensory blockade of the tibial nerve and common peroneal nerve were 69% and 88%, respectively. The success rates of motor blockade of these nerves were 75% and 90%, respectively. The ED50 and ED95 of 0.5% ropivacaine for US-guided popliteal sciatic nerve block were 6 ml and 16 ml, respectively.

A randomized, triple-masked, active-controlled investigation of the relative effects of dose, concentration, and infusion rate for continuous popliteal-sciatic nerve blocks in volunteers

It remains unknown whether local anaesthetic dose is the only factor influencing continuous popliteal-sciatic nerve block effects, or whether concentration, volume, or both exert an influence as well. Bilateral sciatic catheters were inserted in volunteers (n=24). Catheters were randomly assigned to ropivacaine of either 0.1% (8 ml h(-1)) or 0.4% (2 ml h(-1)) for 6 h. The primary endpoint was the tolerance to transcutaneous electrical stimulation within the tibial nerve distribution at hour 6. Secondary endpoints included current tolerance at other time points and plantar flexion maximum voluntary isometric contraction (22 h total). At hour 6, tolerance to cutaneous stimulation for limbs receiving 0.1% ropivacaine was [mean (standard deviation)] 27.0 (20.2) vs26.9 (20.4) mA for limbs receiving 0.4% [estimated mean difference 0.2 mA; 90% confidence interval (CI) -8.2 to 8.5; P=0.02 and 0.03 for lower and upper boundaries, respectively]. Because the 90% CI fell within the prespecified tolerance ±10 mA, we conclude that the effect of the two concentration/volume combinations were equivalent. Similar negative findings were found for the secondary outcomes. For continuous popliteal-sciatic nerve blocks, we found no evidence that local anaesthetic concentration and volume influence block characteristics, suggesting that local anaesthetic dose (mass) is the primary determinant of perineural infusion effects in this anatomic location. These findings suggest that for ambulatory perineural local anaesthetic infusion-for which there is usually a finite local anaesthetic reservoir-decreasing the basal rate while increasing the local anaesthetic concentration may allow for increased infusion duration without compromising postoperative analgesia. NCT01898689.

Safety and effectiveness of bilateral continuous sciatic nerve block for bilateral orthopaedic foot surgery

Severe postoperative pain is a major problem after unilateral and bilateral foot surgery. Continuous regional anaesthesia is often used for unilateral surgery. However, for bilateral surgery, the incidence of complications of continuous bilateral compared with unilateral regional anaesthesia is unknown. To assess the incidence of catheter-related complications of bilateral compared with unilateral continuous regional anaesthesia. A prospective observational study. Bellinzona Regional Hospital, a tertiary teaching hospital. Patients (n = 130) scheduled for elective bilateral or unilateral hallux valgus repair treated with continuous popliteal sciatic nerve block using a continuous infusion of ropivacaine 0.15% at 5 ml h for each popliteal catheter by elastomeric pumps. The incidence of catheter-related complications, effectiveness, pain levels at rest and with motion, patient satisfaction for the first three postoperative days and the incidence of ambulatory visits or readmissions after discharge were measured. A follow-up for neurological or other complications related to regional anaesthesia was performed 6 to 8 weeks after surgery. The incidence of catheter-related complications comparing bilateral with unilateral continuous sciatic popliteal nerve block. There were no differences in the incidence of catheter-related complications between the groups. Pain scores at rest and with motion were comparable between the groups. All patients were fit for discharge home 3 days after surgery. Patient satisfaction was similar between the groups. There were no unplanned ambulatory visits or readmissions due to complications in either group. No complications related to regional anaesthesia were reported during the follow-up. The complication rate, effectiveness and patient satisfaction of bilateral continuous popliteal sciatic nerve block was comparable with unilateral continuous sciatic popliteal nerve block. The follow-up showed that bilateral continuous sciatic popliteal nerve block does not increase the complication rate. However, an outpatient-based study should confirm these data prior to introduction in the ambulatory setting.

Chronic pain 1 year after foot surgery: Epidemiology and associated factors

BackgroundMost studies of chronic postoperative pain focussed on major surgical procedures. Chronic postoperative pain occurred in 10% to 50% of patients and exhibited neuropathic features in 5% to 68% of cases. The objectives of this prospective single-centre study were to determine the rates of occurrence and associated factors of any chronic pain and of neuropathic chronic pain 1year after orthopaedic surgery on the foot. MethodsWe included consecutive patients who underwent scheduled orthopaedic surgery on the foot or ankle at a university hospital centre between 2009 and 2011. All patients received a multimodal analgesia regimen that usually combined a continuous popliteal sciatic nerve block, paracetamol, and ketoprofen, with additional ketamine if deemed appropriate. A telephone interview was conducted 1year after the surgical procedure. The main outcome measures were moderate-to-severe pain (numerical rating scale score>3/10) 1year after surgery at rest and during walking, and presence of neuropathic pain (defined using the DN2 score). Multivariate analysis was performed to look for associations of various perioperative clinical variables with pain. ResultsOne year after surgery, 55 of 260 (21%) patients reported moderate-to-severe pain at rest, 111 (43%) moderate-to-severe pain during walking, and 9 (3%) neuropathic pain. By multivariate analysis, factors independently associated with moderate-to-severe pain at rest and/or during walking 1year after surgery were moderate-to-severe pain during the first postoperative night (P=0.048) and/or day (P=0.043) and revision surgery (P=0.001). DiscussionThe rate of occurrence of moderate-to-severe pain 1year after orthopaedic foot surgery is similar to that seen after major surgical procedures, whereas neuropathic pain seems rare. Orthopaedic surgery on the ankle or hindfoot is not more likely to be followed by chronic pain compared to surgery for hallux valgus or toe abnormalities. There is some evidence that earlier surgery might be beneficial. Level of evidenceIV, prospective observational longitudinal cohort study.