Popliteal Sciatic Block Research Articles

Comparison Of Dexamethasone As An Adjuvant To Ropivacaine With Ropivacaine Alone In USG Guided Popliteal Sciatic Block For Post-Operative Analgesia In Below Knee Surgeries -A Randomized Controlled Trial.

Comparison Of Dexamethasone As An Adjuvant To Ropivacaine With Ropivacaine Alone In USG Guided Popliteal Sciatic Block For Post-Operative Analgesia In Below Knee Surgeries -A Randomized Controlled Trial.

The role of continuous popliteal sciatic block in a patient with acute on chronic limb-threatening ischemia: a case report

The role of continuous popliteal sciatic block in a patient with acute on chronic limb-threatening ischemia: a case report

Continuous Sciatic Popliteal Block as Postoperative Pain Management in Patient with Closed Fracture Right Ankle Undergo ORIF PS Surgery

Introduction: Currently, foot and ankle surgeries are on the rise, and a significant challenge in these cases is the intense post-operative pain that arises from early patient mobilization. Continuous popliteal sciatic block have emerged as a solution, effectively alleviating pain from the intra-operative to post-operative stages for patients undergoing foot and ankle surgery. According to a study conducted by Ding and colleagues, continuous blocks have proven to be more effective than a single injection in providing pain relief.
 Case presentation: A 24-year-old woman diagnosed with a closed fracture of her right ankle is scheduled for open reduction internal fixation (ORIF) with a plate and screws for her right ankle. The patient has an American Society of Anesthesiologists (ASA) physical status of III and is dealing with grade II obesity. A continuous popliteal sciatic block was performed on the patient under ultrasound guidance, with the catheter tip placed outside the perineural area. Postoperatively, the patient received pain management through a regimen of 0.1% bupivacaine, 20 ml volume, administered every 4 hours. Remarkably, the patient experienced minimal pain until the 2nd day after surgery and was discharged home.
 Conclusion: The continuous popliteal sciatic block is a regional anesthetic method that offers potent pain relief for patients undergoing foot and ankle surgery. Extensive evidence supports its effectiveness and safety during administration, making it a reliable choice for pain management in these procedures.

Comparison of Ultrasound-Guided Popliteal Sciatic Block Properties in Diabetic and Nondiabetic Patients.

We aim to share our popliteal sciatic nerve block (PSB) experience, which we applied to diabetic and nondiabetic patients in the operating room of our hospital. The patients who underwent PSB for foot and ankle surgery between October 1, 2021, and December 31, 2021, in Sakarya University Training and Research Hospital were evaluated retrospectively. All nerve blocks were administered by a single anesthesiologist. Demographic data of the patients and the duration of the operation, the type of operation, the time of application of the nerve block, whether it was single or bifurcation block, and the onset times of motor and sensory block were also recorded in the perioperative period. It was determined that PSB was applied to 49 patients over a 3-month period. The mean age of the patients was 61.33 ± 14.03 years, and 12 patients (24.5%) were women. The reason why the patients were operated on was amputation in 21 (42.9%) and wound debridement in 27 (55.1%). There were 37 patients in the diabetic group and 12 patients in the nondiabetic group. There was no significant difference between the two groups in terms of demographic data and operation characteristics, but it was observed that there was a significant difference in both sensory and motor block formation times between the two groups (P < .001). In conclusion, we think that popliteal sciatic nerve block is easy to apply, the complication rate is low, and it is a suitable anesthesia method for patients who will undergo day surgery for foot ulcer.

A peripheral nerve stimulator guided popliteal sciatic nerve block combined with adductor canal block in lower leg surgery- A sole anesthetic technique

In lower leg surgeries involving fractures of distal tibia, ankle surgeries, debridement and PVD surgeries choice of anesthesia is usually regional anesthesia. When these patients are associated with co-morbid cardio-respiratory problems then it will become challenge for anesthesiologist to maintain homeostasis with good surgical anesthesia. Ayukut urfalioglu suggested another alternative technique in the form of Adductor canal block plus Lateral approach popliteal sciatic block as good alternative for these surgeries with better Intra-operative Haemodynamic Stability, additional post-operative pain relief and less requirement of systemic analgesia post-operatively.In this prospective randomised controlled trial, we aim to explore the efficacy of Adductor canal block plus Popliteal Sciatic Block for Lower leg surgeries. Sixty patients (ASA I, II, III) undergoing lower limb surgeries were randomly allocated in 2 groups (30 patients in each group). In Group P patients received PNS guided Adductor canal block combined with popliteal sciatic block and in group S patients received unilateral spinal anesthesia.: The primary objectives were to evaluate duration of sensory and motor block and post-operative pain relief. Secondary objectives included intra operative requirements of additional anesthesia and intraoperative haemodynamic stability.There was significant intraoperative haemodynamic stability and post-operative pain relief attributable to Group P. Time for first requirement of rescue analgesia post-operatively was significantly higher in Group P compared to Group S (Group P Mean SD15.9±5.26 vs 6.05±1.23 in Group S with p= &amp;#60; 0.0001).Combined adductor canal block and popliteal sciatic block can be an alternative technique with advantage of prolonged post-operative analgesia and haemodynamic stability.

PERINEURAL DEXAMETHASONE AS ADJUVANT TO LOCAL ANAESTHETIC AGENT IN ULTRASOUND GUIDED POPLITEAL NERVE BLOCK FOR VARIOUS ANKLE &amp; FOOT SURGERIES

Background: Ankle&amp; foot surgeries are very common surgeries in various age groups like young &amp; geriatric as well as in patients with comorbidities.popliteal nerve block is one of multimodal Anaesthesia &amp; analgesia for same.we have used ultrasound guided block to prevent complications &amp;precise volume at asite for improving Charisteristics of block. Aims of study: To study the technique of giving popliteal nerve blocks with ultrasonographic guidance and evaluate it in terms of: No of attempts ,Time required for sensory and motor blockade,Quality of Intra operative analgesia ,Duration for post operative analgesia , Supplementation required in form of general anaesthesia &amp; Complications encountered. Methods: We have given ultrasonography guided popliteal nerve block in 100 adult patients of ASA grade I/II/III undergoing foot and ankle surgeries. The volume of drug used was 20ml consisting of Lignocaine(1.5%) 10ml and Bupivacaine(0.5%) 10ml+ 2 ml Normal saline in Group A&amp; addition of dexamethasone 8 mg as adjuvant to LA in Group B. Results: The mean time taken to conduct the block was 4.3±1.4 mins in Group A,4.2±1.6 min inGr.B.The mean time taken for sensory onset was 3.8±1.1 mins in Gr A,3.6±1.4min in Gr.B .The mean time taken for motor onset was 7.2± 1.4 mins in GrA,7.0± 1.5 mins in Gr B.The mean time taken for completing the surgery was 39.2±5.0 mins in GrA,38.2±5.2 mins in Gr.B.The mean time taken for complete motor regression was 143.8±13.5 mins in Gr A,340.8±10.5 mins in Gr B.The mean time taken for complete sensory regression was 184.8± 16.8 minsin Gr.A,379.8± 18.8 mins in Gr B.(p&lt;0.05)The patients first complained of pain at the mean time of 239±22.4 minsin Gr A,1069±12.4 minsin Gr B( p&lt;0.001) In both groups,patients have stable haemodynamic parameters throughout the operation.supplementation of sedoanalgesia was given in 4 patients in the form of Injection Midazolam 1mg IV and Injection Fentanyl 50 microgm IV was given in 2 patients and general anaesthesia was given in 2 patients in both groups.No other neurological complications were noticed in our study. Conclusion: ultrasound guided Popliteal nerve block is safe&amp; effective block for various ankle &amp;foot surgeries. Dexamethasone is effective adjuvant in popliteal sciatic block for foot&amp; ankle surgeries as it increase time to analgesic request.

Examining the impact perceptual learning artificial-intelligence-based on the incidence of paresthesia when performing the ultrasound-guided popliteal sciatic block: simulation-based randomized study

ObjectiveTo explore the impact of artificial-intelligence perceptual learning when performing the ultrasound-guided popliteal sciatic block.MethodsThis simulation-based randomized study enrolled residents who underwent ultrasound-guided sciatic nerve block training at the Department of Anesthesiology of Beijing Jishuitan Hospital between January 2022 and February 2022. Residents were randomly divided into a traditional teaching group and an AI teaching group. All residents attended the same nerve block theory courses, while those in the AI teaching group participated in training course using an AI-assisted nerve identification system based on a convolutional neural network instead of traditional training.ResultsA total of 40 residents were included. The complication rates of paresthesia during puncture in the first month of clinical sciatic nerve block practice after training were significantly lower in the AI teaching group than in the traditional teaching group [11 (4.12%) vs. 36 (14.06%), P = 0.000093]. The rates of paresthesia/pain during injection were significantly lower in the AI teaching group than in the traditional teaching group [6 (2.25%) vs. 17 (6.64%), P = 0.025]. The Assessment Checklist for Ultrasound-Guided Regional Anesthesia (32 ± 3.8 vs. 29.4 ± 3.9, P = 0.001) and nerve block self-rating scores (7.53 ± 1.62 vs. 6.49 ± 1.85, P < 0.001) were significantly higher in the AI teaching group than in the traditional teaching group. There were no significant differences in the remaining indicators.ConclusionThe inclusion of an AI-assisted nerve identification system based on convolutional neural network as part of the training program for ultrasound-guided sciatic nerve block via the popliteal approach may reduce the incidence of nerve paresthesia and this might be related to improved perceptual learning.Clinical trialCHiCTR2200055115, registered on 1/ January /2022.

Ease of Single Prick Popliteal Sciatic Block in a Modified Lateral Position

Ultrasound-Guided Popliteal Nerve Block has become a routine plan of anesthesia for below-knee Surgeries. It takes care of post-operative analgesia leading to the reduction of intravenous analgesia. In comparison to multiple pricks, single prick blocks are gaining importance since the success rate is the same, the duration of the procedure is less and patients cooperate better. Patients find to be in a prone position when compared to the lateral position and the ease of block is expected to be better in the lateral position. There are two approaches to block, commonest is the lateral approach which needs a change of needle direction and another prick to block both nerves.

Impact of self-coiling catheters for continuous popliteal sciatic block on postoperative pain level and dislocation rate: a randomized controlled trial

BackgroundDislocation of catheters within the tissue is a challenge in continuous regional anesthesia. A novel self-coiling catheter design is available and has demonstrated a lower dislocation rate in a cadaver model. The dislocation rate and effect on postoperative pain of these catheters in vivo has yet to be determined and were the subjects of this investigation.MethodsAfter ethics committee approval 140 patients undergoing elective distal lower limb surgery were enrolled in this prospective randomized controlled trial. Preoperatively, patients were randomly assigned and received either the conventional (n = 70) or self-coiling catheter (n = 70) for ultrasound-guided popliteal sciatic nerve block in short axis view and by the in-plane approach from lateral to medial. The primary outcome was pain intensity after surgery and on the following three postoperative days. Secondary outcomes investigated were dislocation rate in situ determined by sonography, catheter movement visible from outside, opioid consumption as well as leakage at the puncture site.ResultsAll catheters were successfully inserted. The study population of self-coiling catheters had significantly lower mean numeric rating scale values than the reference cohort on the first (p = 0.01) and second postoperative days (p < 0.01). Sonographic evaluation demonstrated, 42 standard catheters (60%) and 10 self-coiling catheters (14.3%) were dislocated in situ within the first three postoperative days. The externally visible movement of the catheters at insertion site did not differ significantly between groups through the third postoperative day. The opioid consumption was significantly lower in the self-coiling catheter group on the day of surgery and on the second and third postoperative days (p = 0.04, p = 0.03 and p = 0.04, respectively).ConclusionThe self-coiling catheter offers a better postoperative pain control and a lower dislocation rate within the tissue when blocking the popliteal sciatic nerve compared to a conventional catheter. Further trials in large patient cohorts are warranted to investigate the potential beneficial effects of self-coiling catheters for other localisations and other application techniques.Trial registrationThe trial was registered at German Clinical Trials Register (DRKS) on 08/04/2020 (DRKS00020938, retrospectively registered).

Lateral popliteal block in foot and ankle surgery: Comparing ultrasound guidance to nerve stimulation. A prospective randomized trial

BackgroundThe popliteal block has several benefits in foot and ankle surgery. It reduces postoperative pain, limits the use of narcotics and facilitates early discharge. The aim of this prospective randomized trial was to evaluate whether ultrasound guidance improves block characteristics compared to the nerve stimulation technique in lateral popliteal blocks. MethodsPatients were randomized to receive either a lateral popliteal block using neurostimulation or ultrasound guidance. Block performance time, number of needle pricks, number of redirections were recorded. Pain upon admission to and discharge from post anesthesia care unit (PACU) was recorded. Block duration, patient satisfaction, pain at block site and amount of opioids used in PACU and between subsequent followup visits was recorded. Patients were followed for 12 weeks postoperatively. ResultsThere was no statistically significant difference between the two groups in terms of number of pricks, time for the block to wean, pain upon admission to PACU, amount of opioids received in PACU, pain upon discharge from PACU, pain at the operative site, pain at the block site, toe motor function and toe sensation. There was a statistically significant difference in the block procedure performance time between the two groups, with the control group being faster (P<0.0001). A significantly larger number of patients in the control group required more than three needle redirections (P=0.0060). ConclusionsThe lateral sciatic popliteal block using nerve stimulation had similar block characteristics and patient satisfaction with a significantly faster performance time compared to the ultrasound guided technique.Level of evidence: Level I, prospective randomized study.

Role of dexmedetomidine as adjuvant in postoperative sciatic popliteal and adductor canal analgesia in trauma patients: a randomized controlled trial.

BackgroundThe effect of dexmedetomidine as an adjuvant in the adductor canal block (ACB) and sciatic popliteal block (SPB) on the postoperative tramadol-sparing effect following spinal anesthesia has not been evaluated.MethodsIn this randomized, placebo-controlled study, ninety patients undergoing below knee trauma surgery were randomized to either the control group, using ropivacaine in the ACB + SPB; the block Dex group, using dexmedetomidine + ropivacaine in the ACB + SPB; or the systemic Dex group, using ropivacaine in the ACB + SPB + intravenous dexmedetomidine. The primary outcome was a comparison of postoperative cumulative tramadol patient-controlled analgesia (PCA) consumption at 48 hours. Secondary outcomes included time to first PCA bolus, pain score, neurological assessment, sedation score, and adverse effects at 0, 5, 10, 15, and 60 minutes, as well as 4, 6, 12, 18, 24, 30, 36, 42, and 48 hours after the block.ResultsThe mean ± standard deviation of cumulative tramadol consumption at 48 hours was 64.83 ± 51.17 mg in the control group and 41.33 ± 38.57 mg in the block Dex group (P = 0.008), using Mann–Whitney U-test. Time to first tramadol PCA bolus was earlier in the control group versus the block Dex group (P = 0.04). Other secondary outcomes were comparable.ConclusionsPostoperative tramadol consumption was reduced at 48 hours in patients receiving perineural or systemic dexmedetomidine with ACB and SPB in below knee trauma surgery.

Ultrasound-guided popliteal sciatic and adductor canal block for below-knee surgeries in high-risk patients

Background and Aims:Central neuraxial block and general anaesthesia in patients with significant comorbidities are associated with considerable peri-operative morbidity and mortality. This study aims to delineate peripheral nerve block as a suitable alternative technique in high-risk patients posted for below-knee surgery.Methods:Twenty patients with the American Society of Anesthesiologist's (ASA) physical status grade III and IV, aged 30–80 years, scheduled for below-knee surgery from May 2018 to February 2019 were enrolled in this prospective study. All patients received ultrasound-guided popliteal sciatic block with 20 ml 0.5% ropivacaine and adductor canal block with 10 ml 0.375% ropivacaine. The peripheral nerve block success rate, sensory and motor block onset time, haemodynamic parameters, duration of post-operative analgesia and patient's satisfaction were recorded. Descriptive statistics of the study were calculated and the data was analysed using an SPSS statistics 21.0 program.Result:Surgery was performed successfully with no additional analgesic requirement in all patients. The mean duration for sensory and motor block onset time was 3.35 ± 0.49 (mean ± standard deviation) and 4.65 ± 0.48 (mean ± standard deviation) minutes respectively. Haemodynamic parameters were maintained stable throughout the procedure. The average duration of postoperative analgesia was 7.5 ± 0.8 (mean ± standard deviation) hours. Patient overall satisfaction as assessed, by three-point Lickert's scale, was satisfactory.Conclusion:Ultrasound-guided combined popliteal sciatic and adductor canal block is an effective alternative anaesthetic technique for below-knee surgeries with stability of haemodynamic parameters and pain management in high-risk patients.

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.

3D ultrasound estimation of the effective volume for popliteal block at the level of division

Abstract Local anaesthetic injection between the tibial and commmon peroneal nerves within connective tissue sheath results in a predictable diffusion and allows for a reduction in the volume needed to achieve a consistent sciatic popliteal block. Using 3D ultrasound volumetric acquisition, we quantified the visible volume in contact with the nerve along a 5 cm segment. Methods We included 20 consecutive patients scheduled for bunion surgery. Ultrasound guided popliteal block was performed using a posterior, out of plane approach at the level of division of the sciatic nerve. Thirty mL of mepivacaine 1.5% and levobupivacaine 0.5% were slowly injected while assessing the injection pressure and the diffusion of the local anaesthetic. Volumetric acquisition was performed before and after the block to quantify the volume of the sciatic nerve and the volume of the surrounding hypoechoic halo contained inside the connective tissue in a 5 cm segment. Results All blocks were successful within 20 min after the injection. The total estimated volume contained inside the common connective tissue sheath was 6.8 ± 2.6 cm 3 . Of this, the volume of the halo surrounding the nerve was 4.4 ± 1.7 cm 3 and the volume inside the sciatic nerve was 2.4 ± 1.7 cm 3 . Conclusions The volume of local anaesthetic in close contact with the sciatic nerve can be estimated by volumetric acquisition. Our results suggest that the effective volume of local anaesthetic needed for a successful sciatic popliteal block could be reduced to less than 7 mL.

Estimación del volumen de anestésico local en contacto con el nervio ciático en el bloqueo poplíteo

Local anaesthetic injection between the tibial and commmon peroneal nerves within connective tissue sheath results in a predictable diffusion and allows for a reduction in the volume needed to achieve a consistent sciatic popliteal block. Using 3D ultrasound volumetric acquisition, we quantified the visible volume in contact with the nerve along a 5cm segment. MethodsWe included 20 consecutive patients scheduled for bunion surgery. Ultrasound guided popliteal block was performed using a posterior, out of plane approach at the level of división of the sciatic nerve. Thirty ml of mepivacaine 1.5% and levobupivacaine 0.5% were slowly injected while assessing the injection pressure and the diffusion of the local anaesthetic. Volumetric acquisition was performed before and after the block to quantify the the volume of the sciatic nerve and the volume of the surrounding hypoechoic halo contained inside the connective tissue in a 5cm segment. ResultsAll blocks were successful within 20min after the injection. The total estimated volume contained inside the common connective tissue sheath was 6.8±2.6cm3. Of this, the volume of the halo sorrounding the nerve was 4.4±1.7cm3 and the volume inside the sciatic nerve was 2.4±1.7cm3. ConclusionsThe volume of local anaesthetic in close contact with the sciatic nerve can be estimated by volumetric acquisition. Our results suggest that the effective volume of local anaesthetic needed for a successful sciatic popliteal block could be reduced to less than 7ml.

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.

A double-blind randomized controlled trial comparing dexamethasone and clonidine as adjuvants to a ropivacaine sciatic popliteal block for foot surgery.

Background and aimsA popliteal block is effective in managing postoperative pain for foot surgery, but since the duration of analgesia is limited following a single-shot popliteal fossa block technique, methods to prolong effective postoperative analgesia are mandatory. The aim of this study was to assess the effect of adjuvants to ropivacaine on the duration of sensory and motor block.MethodsIn this double-blind randomized placebo-controlled study, we evaluated the analgesic effect of clonidine or dexamethasone (DXM) when added to ropivacaine for hallux valgus surgery. After obtaining institutional ethics research board approval and written informed consent, a total of 72 patients were randomly allocated. Fifty-seven of these patients were statistically analyzed. All patients received an ultrasound-guided single-shot popliteal fossa block with 30 mL of ropivacaine 0.75%, supplemented with saline, clonidine 100 µg, or DXM 5 mg. The primary end point was time to first pain sensation. Secondary end points were time to complete sensory and motor block regression.ResultsCompared to saline, duration to first pain sensation was prolonged by 9 hours (mean ± standard deviation: 31±9 hours) (42%) in the DXM group (P=0.024) and by 6 hours (28±10 hours) (27%) in the clonidine group (P=0.024). Compared to saline, DXM prolonged both complete sensory and motor blockade by 12 hours (25±7 hours) (46%) and 13 hours (36±6 hours) (55%), respectively, while clonidine prolonged complete sensory and motor blockade by 7 hours (30±7 hours) (27%) and 2 hours (22±5 hours) (10%), respectively. DXM prolonged sensory block regression time by 6 hours (21±7 hours) (41%) and clonidine by 2 hours (17±6 hours) (13%) compared to the control group (P=0.006). Similarly, DXM prolonged motor block regression by 7 hours (25±7 hours) (46%) and clonidine by 4 hours (21±4 hours) (19%) (P<0.0001).ConclusionAddition of DXM and clonidine to ropivacaine significantly prolonged the duration of postoperative sensory and motor block.

Ultrasound guided injection inside the common sheath of the sciatic nerve at division level has a higher success rate than an injection outside the sheath

Background and objectiveThe recommendations for the level of injection and ideal placement of the needle tip required for successful ultrasound-guided sciatic popliteal block vary among authors. A hypothesis was made that, when the local anesthetic is injected at the division of the sciatic nerve within the common connective tissue sheath, the block has a higher success rate than an injection outside the sheath. MethodsThirty-four patients scheduled for hallux valgus repair surgery were randomized to receive either a sub-sheath block (n=16) or a peri-sheath block (n=18) at the level of the division of the sciatic nerve at the popliteal fossa. For the sub-sheath block, the needle was advanced out of plane until the tip was positioned between the tibial and peroneal nerves, and local anesthetic was then injected without moving the needle. For the peri-sheath block, the needle was advanced out of plane both sides of the sciatic nerve, to surround the sheath. Mepivacaine 1.5% and levobupivacaine 0.5% 30mL were used in both groups. The progression of motor and sensory block was assessed at 5min intervals. Duration of block was recorded. ResultsAdequate surgical block was achieved in all patients in the subsheath group (100%) compared to 12 patients (67%) in the peri-sheath group at 30min. Sensory block was achieved faster in the subsheath than peri-sheath (9.1±7.4min vs. 19.0±4.0; p<.001). ConclusionsOur study suggests that for successful sciatic popliteal block in less than 30min, local anesthetic should be injected within the sheath.

No Clinical or Electrophysiologic Evidence Proving Intraneural Injection Is Safe

To the Editor: The article by Sala-Blanch et al. 1paints regional anesthesia into an interesting corner. On one hand, the authors demonstrate that intraneural injection happens frequently during nerve stimulator-guided blocks. On the other hand, the article does not provide convincing evidence that intraneural injection is safe. Neuropathy after peripheral nerve block is uncommon and therefore difficult to study from an epidemiologic perspective. For this study, the unbiased estimate of the true event rate for nerve injury after intraneural injection is 0 percent. However, because of the small sample size (n = 16), the upper bound of the 95% CI on this event rate is only 20% (Clopper–Pearson method).The title of the article, “No Clinical or Electrophysiologic Evidence of Nerve Injury After Intraneural Injection During Sciatic Popliteal Block,” is misleading when reported in such a limited number of patients. It provides tacit approval of a practice that may be the cause (albeit rarely) of complications that are devastating to the patient. A large prospective trial of intraneural injections in humans is needed to quantify the risk of this practice. However, such a study is difficult to justify because animal studies already demonstrate that needle trauma alone can cause nerve injury.2,3Even animal studies showing no histologic or electrophysiologic evidence of injury after intraneural injection4do not address the most common symptoms of injury, which are paresthesia, dysesthesia, and pain. The majority of these symptoms occur without electrophysiologic abnormalities.5There is a striking paradox in this study. The investigators unknowingly performed intraneural injection in 94% of patients with the nerve stimulator. Meanwhile, their colleagues (in the same study) used ultrasound to assess local anesthetic distribution with such precision as to “identify hypoechoic aliquots of fluid between nerve fascicles.”1Few reports have illustrated the gap in capability between these two technologies so well.The truth is we do not know how often intraneural injection leads to nerve injury. However, it is reasonable to assume that piercing and injecting nerves is not therapeutic in any way. Instead of trying to convince ourselves that nerve injection and needle trauma are not so bad, why not just stop doing it? After all, we have the technology.

Ultrasound-Guided Popliteal Sciatic Block with a Single Injection at the Sciatic Division Results in Faster Block Onset than the Classical Nerve Stimulator Technique

For successful, fast-onset sciatic popliteal block (SPB), either a single injection above the division of the sciatic nerve, or 2 injections to block the tibial nerve (TN) and common peroneal nerve (CPN) separately have been recommended. In this study, we compared the traditional nerve stimulator (NS)-guided SPB above the division of the sciatic nerve with the ultrasound (US)-guided block with single injection of local anesthetic (LA) between the TN and CPN at the level of their division. We hypothesized that US-SPB with a single injection between TN and CPN would result in faster block onset than a single-injection NS-SPB. Fifty-two patients were randomized to receive either an NS-SPB or a US-SPB. For both blocks, a single injection of 20 mL mepivacaine 1.5% was given using an automated injection pump while controlling for injection force. For NS-SPB, a TN response below 0.5 mA was sought 7 cm above the popliteal fossa crease (and proximal to the divergence of the TN and peroneal nerves). For US-SPB, the injection was made after a US-guided needle was inserted between the TN and CPN at the level of their separation. Motor response was not actively sought but registered if present. The location and spread of LA were evaluated by US in both groups. Onset of motor and sensory blocks was serially assessed in 5-minute intervals in the TN and CPN divisions and compared between the groups. All patients in both groups had successful block at 30 minutes after the injection, defined as sensory block to allow surgery without supplementation. A higher proportion of patients in the US-SPB group had a complete sensory (80% vs 4%, P < 0.001) and motor block (60% vs 8%, P < 0.001), defined as anesthesia and paralysis in all nerve territories, at 15 minutes after injection. US signs of intraepineural injection were present in 19 patients (73%) in the NS-SPB group and 25 patients (100%) in the US-SPB group (P < 0.001). A single injection of LA in US-SPB with needle insertion at the separation of the TN and CPN results in a similar success rate at 30 minutes; however, more patients in the US-SPB group than in the NS-SPB group had complete block at 15 minutes.