Post-mastectomy cancer recurrence with and without a continuous paravertebral block in the immediate postoperative period: a prospective multi-year follow-up pilot study of a randomized, triple-masked, placebo-controlled investigation.

PURPOSE: Retrospective studies have associated perioperative regional anesthesia/analgesia during mastectomy for breast cancer with a decreased incidence of cancer recurrence. However, to date, no prospective data from a randomized controlled trial have been reported. In a previous study we found that extending a single-injection paravertebral block with a multiple-day perineural local anesthetic infusion improves analgesia. This follow-up study investigates the rates of cancer recurrence for the single-injection and multiple-day infusion treatments. METHODS: Patients undergoing unilateral (n = 24) or bilateral mastectomy (n = 36) were included in the study. All patients had been diagnosed with breast cancer or tumor in situ, except for six patients who were receiving prophylactic bilateral mastectomy and were excluded from analyses. Patients received unilateral or bilateral single-injection thoracic paravertebral block(s) corresponding to their surgical site(s) with ropivacaine and perineural catheter(s). Subsequently, patients were randomized to receive either ropivacaine 0.4% (n = 30) or normal saline (n = 30) via their catheter(s) until catheter removal on postoperative day 3. Cancer recurrence from the date of surgery until at least 2 years post surgery was investigated via chart review. RESULTS: Five of the 54 (9.2%) patients experienced a cancer recurrence following mastectomy-3 of 26 (11.5%) of the patients with perineural ropivacaine and 2 of 28 (7.1%) of the patients with perineural saline. CONCLUSIONS: This pilot study found no evidence that extending a single-injection paravertebral block with a multi-day perineural local anesthetic infusion decreases the risk of post-mastectomy cancer recurrence. However, due to the small sample size of this investigation, further research is needed to draw definitive conclusions.

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.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Persistent postmastectomy pain and pain-related physical and emotional functioning with and without a continuous paravertebral nerve block: a prospective 1-year follow-up assessment of a randomized, triple-masked, placebo-controlled study.

BACKGROUND: In a previous randomized, triple-masked, placebo-controlled study, the authors demonstrated that extending a single-injection paravertebral nerve block with a multiple-day perineural local anesthetic infusion improves analgesia and decreases pain-related dysfunction during the 3-day infusion but not subsequent to catheter removal within 1 month after mastectomy. This report describes a prospective follow-up study of the previously published trial to investigate the possibility that extending a single-injection paravertebral block with a multiple-day infusion may decrease persistent postsurgical pain as well as pain-induced emotional and functional dysfunction 1 year after mastectomy. METHODS: Subjects undergoing uni- or bilateral mastectomy received unilateral (n = 24) or bilateral (n = 36) single-injection thoracic paravertebral block(s) with ropivacaine and perineural catheter(s). The subjects were randomized to receive either ropivacaine 0.4 % (n = 30) or normal saline (n = 30) via their catheters until the catheters were removed on postoperative day 3. Chronic pain and pain-related physical and emotional dysfunction were measured using the Brief Pain Inventory (BPI). RESULTS: No statistically significant difference between treatments 3 months after surgery was observed with the BPI. In contrast, after 12 months, only 4 subjects (13 %) who had received a perineural ropivacaine infusion reported pain-induced dysfunction compared with 14 (47 %) who had received saline infusion (P = 0.011). At 12 months, the mean BPI was 1.6 ± 4.6 for the subjects who received ropivacaine versus 5.9 ± 11.3 for the subjects who received saline (P = 0.007). CONCLUSIONS: Adding a multiple-day, continuous ropivacaine infusion to a single-injection ropivacaine paravertebral nerve block may result in a lower incidence of pain as well as pain-related physical and emotional dysfunction 1 year after mastectomy.

Continuous transversus abdominis plane (TAP) blocks for postoperative pain control after hernia surgery: a randomized, triple-masked, placebo-controlled study.

BACKGROUND: Single-injection transversus abdominis plane (TAP) block provides postoperative analgesia and decreases supplemental analgesic requirements. However, there is currently no evidence from randomized, controlled studies investigating the possible benefits of continuous TAP blocks. Therefore, the aim of this randomized, triple-masked, placebo-controlled study was to determine if benefits are afforded by adding a multiple-day, ambulatory, continuous ropivacaine TAP block to a single-injection block following hernia surgery. METHODS: Preoperatively, subjects undergoing unilateral inguinal (N=19) or peri-umbilical (N=1) hernia surgery received unilateral or bilateral TAP perineural catheter(s), respectively. All received a ropivacaine 0.5% (20 mL) bolus via the catheter(s). Subjects were randomized to either postoperative perineural ropivacaine 0.2% or normal saline using portable infusion pump(s). Subjects were discharged home where the catheter(s) were removed the evening of postoperative day (POD) 2. Subjects were contacted on POD 0-3. The primary endpoint was average pain with movement (scale: 0-10) queried on POD 1. RESULTS: Twenty subjects of a target 30 were enrolled due to the primary surgeon's unanticipated departure from the institution. Average pain queried on POD 1 for subjects receiving ropivacaine (N=10) was a mean (standard deviation) of 3.0 (2.6) vs 2.8 (2.7) for subjects receiving saline (N=10; 95% confidence interval difference in means -2.9 to 3.4; P=0.86). There were no statistically significant differences detected between treatment groups in any secondary endpoint. CONCLUSIONS: The results of this study do not support adding an ambulatory, continuous ropivacaine infusion to a single-injection ropivacaine TAP block for hernia surgery. However, the present investigation was underpowered, and further study is warranted.

Treating intractable phantom limb pain with ambulatory continuous peripheral nerve blocks: a pilot study.

BACKGROUND: There is currently no reliable treatment for phantom limb pain (PLP). Chronic PLP and associated cortical abnormalities may be maintained from abnormal peripheral input, raising the possibility that a continuous peripheral nerve block (CPNB) of extended duration may permanently reorganize cortical pain mapping, thus providing lasting relief. METHODS: Three men with below-the-knee (2) or -elbow (1) amputations and intractable PLP received femoral/sciatic or infraclavicular perineural catheter(s), respectively. Subjects were randomized in a double-masked fashion to receive perineural ropivacaine (0.5%) or normal saline for over 6 days as outpatients using portable electronic infusion pumps. Four months later, subjects returned for repeated perineural catheter insertion and received an ambulatory infusion with the alternate solution ("crossover"). Subjects were followed for up to 1 year. RESULTS: By chance, all three subjects received saline during their initial infusion and reported little change in their PLP. One subject did not receive crossover treatment, but the remaining two subjects reported complete resolution of their PLP during and immediately following treatment with ropivacaine. One subject experienced no PLP recurrence through the 52-week follow-up period and the other reported mild PLP occurring once each week of just a small fraction of his original pain (pretreatment: continuous PLP rated 10/10; posttreatment: no PLP at baseline with average of one PLP episode each week rated 2/10) for 12 weeks (lost to follow-up thereafter). CONCLUSIONS: A prolonged ambulatory CPNB may be a reliable treatment for intractable PLP. The results of this pilot study suggest that a large, randomized clinical trial is warranted.

Choice of loco-regional anesthetic technique affects operating room efficiency for carpal tunnel release.

Intravenous regional anesthesia (Bier block) is indicated for minor procedures such as carpal tunnel release but must be performed in the operating room. We hypothesize that preoperative peripheral nerve blocks decrease anesthesia-controlled time compared to Bier block for carpal tunnel release. With IRB approval, we reviewed surgical case data from a tertiary care university hospital outpatient surgery center for 1 year. Unilateral carpal tunnel release cases were grouped by anesthetic technique: (1) preoperative nerve blocks, or (2) Bier block. The primary outcome was anesthesia-controlled time (minutes). Secondary outcomes included surgical time and time for nerve block performance in minutes, when applicable. Eighty-nine cases met criteria for analysis (40 nerve block and 49 Bier block). Anesthesia-controlled time [median (10th-90th percentiles)] was shorter for the nerve block group compared to Bier block [11 (6-18) vs. 13 (9-20) min, respectively; p = 0.02). Surgical time was also shorter for the nerve block group vs. the Bier block group [13 (8-21) and 17 (10-29) min, respectively; p < 0.01), but nerve blocks took 10 (5-28) min to perform. Ultrasound-guided nerve blocks performed preoperatively reduce anesthesia-controlled time compared to Bier block and may be a useful anesthetic modality in some practice environments.

Continuous femoral nerve blocks: the impact of catheter tip location relative to the femoral nerve (anterior versus posterior) on quadriceps weakness and cutaneous sensory block.

BACKGROUND: During a continuous femoral nerve block, the influence of catheter tip position relative to the femoral nerve on infusion characteristics remains unknown. METHODS: We inserted bilateral femoral perineural catheters in volunteers (ultrasound-guided, needle in-plane). Subjects' dominant side was randomized to have the catheter tip placed either anterior or posterior to the femoral nerve. The contralateral limb received the alternative position. Ropivacaine 0.1% was administered through both catheters concurrently for 6 hours (4 mL/h). Outcome measures included the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle and tolerance to cutaneous electrical current over to the distal quadriceps tendon. Measurements were performed at hour 0 (baseline), and on the hour until hour 9, as well as hour 22. The primary end point was the MVIC of the quadriceps at hour 6. RESULTS: As a percentage of the baseline measurement, quadriceps MVIC for limbs with anterior (n = 16) and posterior (n = 16) catheter tip placement did not differ to a statistically significant degree at hour 6 (mean [SD] 29% [26] vs 30% [28], respectively; 95% confidence interval: -22% to 20%; P = 0.931), or at any other time point. However, the maximum tolerance to cutaneous electrical current was higher in limbs with anterior compared with posterior catheter tip placement at hour 6 (20 [23] mA vs 6 [4] mA, respectively; 95% confidence interval: 1-27 mA; P = 0.035), as well as at hours 1, 7, 8, and 9 (P < 0.04). CONCLUSIONS: This study documents the significant (70%-80%) quadriceps femoris weakness induced by a continuous femoral nerve block infusion at a relatively low dose of ropivacaine (4 mg/h) delivered through a perineural catheter located both anterior and posterior to the femoral nerve. In contrast, an anterior placement increases cutaneous sensory block compared with a posterior insertion, without a concurrent relative increase in motor block.

Continuous femoral nerve blocks: varying local anesthetic delivery method (bolus versus basal) to minimize quadriceps motor block while maintaining sensory block.

BACKGROUND: Whether the method of local anesthetic administration for continuous femoral nerve blocks--basal infusion versus repeated hourly bolus doses--influences block effects remains unknown. METHODS: Bilateral femoral perineural catheters were inserted in volunteers (n = 11). Ropivacaine 0.1% was concurrently administered through both catheters: a 6-h continuous 5 ml/h basal infusion on one side and 6 hourly bolus doses on the contralateral side. The primary endpoint was the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle at hour 6. Secondary endpoints included quadriceps MVIC at other time points, hip adductor MVIC, and cutaneous sensation 2 cm medial to the distal quadriceps tendon in the 22 h after initiation of local anesthetic administration. RESULTS: Quadriceps MVIC for limbs receiving 0.1% ropivacaine as a basal infusion declined by a mean (SD) of 84% (19) compared with 83% (24) for those receiving 0.1% ropivacaine as repeated bolus doses between baseline and hour 6 (paired t test P = 0.91). Intrasubject comparisons (left vs. right) also reflected a lack of difference: the mean basal-bolus difference in quadriceps MVIC at hour 6 was -1.1% (95% CI -22.0-19.8%). The similarity did not reach the a priori threshold for concluding equivalence, which was the 95% CI decreasing within ± 20%. There were similar minimal differences in the secondary endpoints during local anesthetic administration. CONCLUSIONS: This study did not find evidence to support the hypothesis that varying the method of local anesthetic administration--basal infusion versus repeated bolus doses--influences continuous femoral nerve block effects to a clinically significant degree.

Continuous femoral versus posterior lumbar plexus nerve blocks for analgesia after hip arthroplasty: a randomized, controlled study.

BACKGROUND: Hip arthroplasty frequently requires potent postoperative analgesia, often provided with an epidural or posterior lumbar plexus local anesthetic infusion. However, American Society of Regional Anesthesia guidelines now recommend against epidural and continuous posterior lumbar plexus blocks during administration of various perioperative anticoagulants often administered after hip arthroplasty. A continuous femoral nerve block is a possible analgesic alternative, but whether it provides comparable analgesia to a continuous posterior lumbar plexus block after hip arthroplasty remains unclear. We therefore tested the hypothesis that differing the catheter insertion site (femoral versus posterior lumbar plexus) after hip arthroplasty has no impact on postoperative analgesia. METHODS: Preoperatively, subjects undergoing hip arthroplasty were randomly assigned to receive either a femoral or a posterior lumbar plexus stimulating catheter inserted 5 to 15 cm or 0 to 1 cm past the needle tip, respectively. Postoperatively, patients received perineural ropivacaine, 0.2% (basal 6 mL/hr, bolus 4 mL, 30-minute lockout) for at least 2 days. The primary end point was the average daily pain scores as measured with a numeric rating scale (0-10) recorded in the 24-hour period beginning at 07:30 the morning after surgery, excluding twice-daily physical therapy sessions. Secondary end points included pain during physical therapy, ambulatory distance, and supplemental analgesic requirements during the same 24-hour period, as well as satisfaction with analgesia during hospitalization. RESULTS: The mean (SD) pain scores for subjects receiving a femoral infusion (n = 25) were 3.6 (1.8) versus 3.5 (1.8) for patients receiving a posterior lumbar plexus infusion (n = 22), resulting in a group difference of 0.1 (95% confidence interval -0.9 to 1.2; P = 0.78). Because the confidence interval was within a prespecified -1.6 to 1.6 range, we conclude that the effect of the 2 analgesic techniques on postoperative pain was equivalent. Similarly, we detected no differences between the 2 treatments with respect to the secondary end points, with one exception: subjects with a femoral catheter ambulated a median (10th-90th percentiles) 2 (0-17) m the morning after surgery, in comparison with 11 (0-31) m for subjects with a posterior lumbar plexus catheter (data nonparametric; P = 0.02). CONCLUSIONS: After hip arthroplasty, a continuous femoral nerve block is an acceptable analgesic alternative to a continuous posterior lumbar plexus block when using a stimulating perineural catheter. However, early ambulatory ability suffers with a femoral infusion.

Continuous peripheral nerve blocks: is local anesthetic dose the only factor, or do concentration and volume influence infusion effects as well?

BACKGROUND: The main determinant of continuous peripheral nerve block effects--local anesthetic concentration and volume or simply total drug dose--remains unknown. METHODS: We compared two different concentrations and basal rates of ropivacaine--but at equivalent total doses--for continuous posterior lumbar plexus blocks after hip arthroplasty. Preoperatively, a psoas compartment perineural catheter was inserted. Postoperatively, patients were randomly assigned to receive perineural ropivacaine of either 0.1% (basal 12 ml/h, bolus 4 ml) or 0.4% (basal 3 ml/h, bolus 1 ml) for at least 48 h. Therefore, both groups received 12 mg of ropivacaine each hour with a possible addition of 4 mg every 30 min via a patient-controlled bolus dose. The primary endpoint was the difference in maximum voluntary isometric contraction (MVIC) of the ipsilateral quadriceps the morning after surgery, compared with the preoperative MVIC, expressed as a percentage of the preoperative MVIC. Secondary endpoints included hip adductor and hip flexor MVIC, sensory levels in the femoral nerve distribution, hip range-of-motion, ambulatory ability, pain scores, and ropivacaine consumption. RESULTS: Quadriceps MVIC for patients receiving 0.1% ropivacaine (n = 26) declined by a mean (SE) of 64.1% (6.4) versus 68.0% (5.4) for patients receiving 0.4% ropivacaine (n = 24) between the preoperative period and the day after surgery (95% CI for group difference: -8.0-14.4%; P = 0.70). Similarly, the groups were found to be equivalent with respect to secondary endpoints. CONCLUSIONS: For continuous posterior lumbar plexus blocks, local anesthetic concentration and volume do not influence nerve block characteristics, suggesting that local anesthetic dose (mass) is the primary determinant of perineural infusion effects.

Prepuncture ultrasound imaging to predict transverse process and lumbar plexus depth for psoas compartment block and perineural catheter insertion: a prospective, observational study.

BACKGROUND: All widely used psoas compartment block/catheter techniques have a common limitation: external landmarks do not accurately predict lumbar plexus depth, leaving practitioners to "guess" at what depth to stop advancing the placement needle when neither transverse process nor lumbar plexus is intercepted. We assessed the accuracy of ultrasound in estimating transverse process depth before needle insertion and prediction of actual needle-to-plexus intercept depth for psoas compartment nerve blocks and perineural catheter insertion. METHODS: Before needle insertion, ultrasound was used to estimate the depth of the transverse process lying directly anterior to the intercrestal line. If a transverse process was not directly anterior to the intercrestal line, then the process immediately caudad to the line was imaged. The ultrasound transducer remained in the parasagittal plane, perpendicular to the skin. After this measurement, the transducer was removed, an insulated needle connected to a nerve stimulator inserted in the parasagittal plane, and the depth of both the transverse process (if contacted) and lumbar plexus noted. A perineural catheter was subsequently inserted. RESULTS: Of 53 enrolled subjects, in 50 cases (94%), the transverse processes were identified by ultrasound at a median (interquartile; range) depth of 5.0 cm (4.5-5.5 cm; 3.5-7.5 cm). In 27 subjects (54%), a transverse process was positioned directly anterior to the intercrestal line, and in all of these subjects, the transverse process was intercepted with the block needle a median of 0.5 cm (0.0-1.0 cm; 0.0-1.0 cm) within the predicted depth. In all 50 subjects in whom the transverse processes were identified by ultrasound, the actual lumbar plexus depth measured with the needle was a median of 7.5 cm (7.0-8.5 cm; 5.0-9.5 cm), and the plexus depth was a median of 2.5 cm (2.0-3.0 cm; 0.2-4.0 cm) past the estimated transverse process depth by ultrasound. By ultrasound, the intersection of the middle and lateral thirds of the intercrestal line between the midline and a parallel line through the posterosuperior iliac spine was too lateral to permit needle-transverse process contact in 50% of the subjects. However, moving the transducer 0.75 cm toward the midline allowed for transverse process imaging in all subjects. CONCLUSIONS: For psoas compartment blocks/catheters, prepuncture ultrasound imaging accurately predicts transverse process depth to within 1 cm, and if the lumbar plexus is estimated to be within 3 cm of the transverse process, ultrasound allows prediction of maximal lumbar plexus depth to within 1 cm.

Comparative efficacy of ultrasound-guided and stimulating popliteal-sciatic perineural catheters for postoperative analgesia.

PURPOSE: Perineural catheter insertion using ultrasound guidance alone is a relatively new approach. Previous studies have shown that ultrasound-guided catheters take less time to place with high placement success rates, but the analgesic efficacy compared with the established stimulating catheter technique remains unknown. We tested the hypothesis that popliteal-sciatic perineural catheter insertion relying exclusively on ultrasound guidance results in superior postoperative analgesia compared with stimulating catheters. METHODS: Preoperatively, subjects receiving a popliteal-sciatic perineural catheter for foot or ankle surgery were assigned randomly to either ultrasound guidance (bolus via needle with non-stimulating catheter insertion) or electrical stimulation (bolus via catheter). We used 1.5% mepivacaine 40 mL for the primary surgical nerve block and 0.2% ropivacaine (basal 8 mL·hr(-1); bolus 4 mL; 30 min lockout) was infused postoperatively. The primary outcome was average surgical pain on postoperative day one. RESULTS: Forty of the 80 subjects enrolled were randomized to each treatment group. One of 40 subjects (2.5%) in the ultrasound group failed catheter placement per protocol vs nine of 40 (22.5%) in the stimulating catheter group (P = 0.014). The difference in procedural duration (mean [95% confidence interval (CI)]) was -6.48 (-9.90 - -3.05) min, with ultrasound requiring 7.0 (4.0-14.1) min vs stimulation requiring 11.0 (5.0-30.0) min (P < 0.001). The average pain scores of subjects who provided data on postoperative day one were somewhat higher for the 33 ultrasound subjects than for the 26 stimulation subjects (5.0 [1.0-7.8] vs 3.0 [0.0-6.5], respectively; P = 0.032), a difference (mean [95%CI]) of 1.37 (0.03-2.71). CONCLUSION: For popliteal-sciatic perineural catheters, ultrasound guidance takes less time and results in fewer placement failures compared with stimulating catheters. However, analgesia may be mildly improved with successfully placed stimulating catheters. Clinical trial registration number NCT00876681.

Preliminary experience with a novel ultrasound-guided supraclavicular perineural catheter insertion technique for perioperative analgesia of the upper extremity.

OBJECTIVE: Brachial plexus perineural catheters provide specific analgesia for upper extremity surgery. Although single-injection ultrasound-guided supraclavicular blocks have been described, little is known about the efficacy of perineural catheters inserted using this approach. We present our experience with ultrasound-guided supraclavicular perineural catheters for distal upper extremity surgery. METHODS: In this case series, 10 patients who underwent upper extremity surgery for orthopedic trauma at a tertiary care university hospital received a supraclavicular brachial plexus perineural catheter for postoperative pain management. In all patients, a nonstimulating catheter was inserted using an ultrasound-guided technique with the catheter tip remaining under direct vision until placement needle withdrawal. Postoperatively, a perineural ropivacaine, 0.2%, infusion was administered at a basal rate of 6 mL/h with a patient-controlled bolus of 4 mL and a lockout interval of 30 minutes. RESULTS: Of the 10 patients, all had successful perineural catheter placement. Patients required a median (range) of 0 (0-100) µg of fentanyl for catheter insertion analgesia. There were no vascular punctures or other direct procedure-related complications. Catheters were maintained for a median (range) of 4 (2-5) days in both hospitalized and ambulatory patients. Median (range) pain scores on postoperative days 1 and 2 were 5 (0-7) and 4 (3-6), respectively, on a numeric rating scale. Three patients' catheters were removed by patient request or dislodged on postoperative day 1. CONCLUSIONS: Supraclavicular brachial plexus perineural catheter insertion using ultrasound guidance is feasible and deserves further study with a randomized controlled trial comparing this relatively new technique with more established approaches.

A trainee-based randomized comparison of stimulating interscalene perineural catheters with a new technique using ultrasound guidance alone.

OBJECTIVE: Compared to the well-established stimulating catheter technique, the use of ultrasound guidance alone for interscalene perineural catheter insertion is a recent development and has not yet been examined in a randomized fashion. We hypothesized that an ultrasound-guided technique would require less time and produce equivalent results compared to electrical stimulation (ES) when trainees attempt interscalene perineural catheter placement. METHODS: Preoperatively, patients receiving an interscalene perineural catheter for shoulder surgery were randomly assigned to an insertion protocol using either ultrasound guidance with a nonstimulating catheter or ES with a stimulating catheter. The primary outcome was the procedural duration (in minutes), starting when the ultrasound probe (ultrasound group) or catheter insertion needle (ES group) first touched the patient and ending when the catheter insertion needle was removed after catheter insertion. RESULTS: All ultrasound-guided catheters (n = 20) were placed successfully and resulted in surgical anesthesia versus 85% of ES-guided catheters (n = 20; P = .231). Perineural catheters placed by ultrasound (n = 20) took a median (10th-90th percentiles) of 8.0 (5.0-15.5) minutes compared to 14.0 (5.0-30.0) minutes for ES (n = 20; P = .022). All catheters placed according to the protocol in both treatment groups resulted in a successful nerve block; however, 1 patient in the ES group had local anesthetic spread to the epidural space. There was 1 vascular puncture using ultrasound guidance compared to 5 in the ES-guided catheter group (P = .182). CONCLUSIONS: Trainees using a new ultrasound-guided technique can place inter-scalene perineural catheters in less time compared to a well-documented technique using ES with a stimulating catheter and can produce equivalent results.

Continuous interscalene brachial plexus block via an ultrasound-guided posterior approach: a randomized, triple-masked, placebo-controlled study.

BACKGROUND: The posterior approach for placing continuous interscalene catheters has not been studied in a controlled investigation. In this randomized, triple-masked, placebo-controlled study, we tested the hypothesis that an ultrasound-guided continuous posterior interscalene block provides superior postoperative analgesia compared to a single-injection ropivacaine interscalene block after moderately painful shoulder surgery. METHODS: Preoperatively, subjects received a stimulating interscalene catheter using an ultrasound-guided, in-plane posterior approach. All subjects received an initial bolus of ropivacaine. Postoperatively, subjects were discharged with oral analgesics and a portable infusion device containing either ropivacaine 0.2% or normal saline programmed to deliver a perineural infusion over 2 days. The primary outcome was average pain on postoperative day (POD) 1 (scale: 0-10). Secondary outcomes included least and worst pain scores, oral opioid requirements, sleep disturbances, patient satisfaction, and incidence of complications. RESULTS: Of the 32 subjects enrolled, 30 perineural catheters were placed per protocol. Continuous ropivacaine perineural infusion (n = 15) produced a statistically and clinically significant reduction in average pain (median [10th-90th percentile]) on POD 1 compared with saline infusion (n = 15) after initial ropivacaine bolus (0.0 [0.0-5.0] versus 3.0 [0.0-6.0], respectively; P < 0.001). Median oral opioid consumption (oxycodone) was lower in the ropivacaine group than in the placebo group on POD 1 (P = 0.002) and POD 2 (P = 0.002). Subjects who received a ropivacaine infusion suffered fewer sleep disturbances than those in the placebo group (P = 0.005 on POD 0 and 1 nights) and rated their satisfaction with analgesia higher than subjects who received normal saline (P < 0.001). CONCLUSIONS: Compared to a single-injection interscalene block, a 2-day continuous posterior interscalene block provides greater pain relief, minimizes supplemental opioid requirements, greatly improves sleep quality, and increases patient satisfaction after moderate-to-severe painful outpatient shoulder surgery.

The effects of local anesthetic concentration and dose on continuous infraclavicular nerve blocks: a multicenter, randomized, observer-masked, controlled study.

BACKGROUND: It remains unclear whether local anesthetic concentration or total drug dose is the primary determinant of continuous peripheral nerve block effects. The only previous investigation, involving continuous popliteal-sciatic nerve blocks, specifically addressing this issue reported that insensate limbs were far more common with higher volumes of relatively dilute ropivacaine compared with lower volumes of relatively concentrated ropivacaine. However, it remains unknown if this relationship is specific to the sciatic nerve in the popliteal fossa or whether it varies depending on anatomic location. We therefore tested the null hypothesis that providing ropivacaine at different concentrations and rates, but at an equal total basal dose, produces comparable effects when used in a continuous infraclavicular brachial plexus block. METHODS: Preoperatively, an infraclavicular catheter was inserted using the coracoid approach in patients undergoing moderately painful orthopedic surgery distal to the elbow. Patients were randomly assigned to receive a postoperative perineural ropivacaine infusion of either 0.2% (basal 8 mL/h, bolus 4 mL) or 0.4% (basal 4 mL/h, bolus 2 mL) through the second postoperative day. Both groups, therefore, received 16 mg of ropivacaine each hour with a possible addition of 8 mg every 30 min via a patient-controlled bolus dose. Our primary end point was the incidence of an insensate limb during the 24-h period beginning the morning after surgery. Secondary end points included analgesia and patient satisfaction. RESULTS: Patients given 0.4% ropivacaine (n = 27) experienced an insensate limb, a mean (sd) of 1.8 (1.6) times, compared with 0.6 (0.9) times for subjects receiving 0.2% ropivacaine (n = 23; estimated difference = 1.2 episodes, 95% confidence interval, 0.5-1.9 episodes; P = 0.001). Satisfaction with postoperative analgesia (scale 0-10, 10 = highest) was scored a median (25th-75th percentiles) of 10.0 (8.0-10.0) in Group 0.2% and 7.0 (5.3-8.9) in Group 0.4% (P = 0.018). Analgesia was similar in each group. CONCLUSIONS: For continuous infraclavicular nerve blocks, local anesthetic concentration and volume influence perineural infusion effects in addition to the total mass of local anesthetic administered. Insensate limbs were far more common with smaller volumes of relatively concentrated ropivacaine. This is the opposite of the relationship previously reported for continuous popliteal-sciatic nerve blocks. The interaction between local anesthetic concentration and volume is thus complex and varies among catheter locations.

Bilateral infraorbital nerve blocks decrease postoperative pain but do not reduce time to discharge following outpatient nasal surgery.

PURPOSE: While infraorbital nerve blocks have demonstrated analgesic benefits for pediatric nasal and facial plastic surgery, no studies to date have explored the effect of this regional anesthetic technique on adult postoperative recovery. We designed this study to test the hypothesis that infraorbital nerve blocks combined with a standardized general anesthetic decrease the duration of recovery following outpatient nasal surgery. METHODS: At a tertiary care university hospital, healthy adult subjects scheduled for outpatient nasal surgery were randomly assigned to receive bilateral infraorbital injections with either 0.5% bupivacaine (Group IOB) or normal saline (Group NS) using an intraoral technique immediately following induction of general anesthesia. All subjects underwent a standardized general anesthetic regimen and were transported to the recovery room following tracheal extubation. The primary outcome was the duration of recovery (minutes) from recovery room admission until actual discharge to home. Secondary outcomes included average and worst pain scores, nausea and vomiting, and supplemental opioid requirements. RESULTS: Forty patients were enrolled. A statistically significant difference in mean [SD] recovery room duration was not observed between Groups IOB and NS (131 [61] min vs 133 [58] min, respectively; P = 0.77). Subjects in Group IOB did experience a reduction in average pain on a 0-100 mm scale (mean [95% confidence interval]) compared to Group NS (-11 [-21 to 0], P = 0.047), but no other comparison of secondary outcomes was statistically significant. CONCLUSIONS: When added to a standardized general anesthetic, bilateral IOB do not decrease actual time to discharge following outpatient nasal surgery despite a beneficial effect on postoperative pain.

Ultrasound guidance versus electrical stimulation for femoral perineural catheter insertion.

OBJECTIVE: Continuous femoral nerve blocks provide potent analgesia and other benefits after knee surgery. Perineural catheter placement techniques using ultrasound guidance and electrical stimulation (ES) have been described, but the optimal method remains undetermined. We tested the hypothesis that ultrasound guidance alone requires less time for femoral perineural catheter insertion and produces equivalent results compared with ES alone. METHODS: Preoperatively, patients receiving a femoral perineural catheter for knee surgery were randomly assigned to either ultrasound guidance with a nonstimulating catheter or ES with a stimulating catheter. The primary outcome was the catheter placement procedure time (minutes) starting when the ultrasound transducer (ultrasound group) or catheter insertion needle (ES group) first touched the patient and ending when the catheter insertion needle was removed after catheter insertion. RESULTS: Perineural catheters placed with ultrasound guidance (n = 20) took a median (10th-90th percentiles) of 5.0 (3.9-10.0) minutes compared with 8.5 (4.8-30.0) minutes for ES (n = 20; P = .012). All ultrasound-guided catheters were placed according to the protocol (n = 20) versus 85% of ES-guided catheters (n = 20; P = .086). Patients in the ultrasound group had a median procedure-related discomfort score of 0.5 (0.0-3.1) compared with 2.5 (0.0-7.6) for the ES group (P = .015). There were no vascular punctures with ultrasound guidance versus 4 in the ES group (P = .039). CONCLUSIONS: Placement of femoral perineural catheters takes less time with ultrasound guidance compared with ES. In addition, ultrasound guidance produces less procedure-related pain and prevents inadvertent vascular puncture.

Ultrasound guidance versus electrical stimulation for infraclavicular brachial plexus perineural catheter insertion.

OBJECTIVE: Electrical stimulation (ES)- and ultrasound-guided placement techniques have been described for infraclavicular brachial plexus perineural catheters but to our knowledge have never been previously compared in a randomized fashion, leaving the optimal method undetermined. We tested the hypothesis that infraclavicular catheters placed via ultrasound guidance alone require less time for placement and produce equivalent results compared with catheters placed solely via ES. METHODS: Preoperatively, patients receiving an infraclavicular perineural catheter for distal upper extremity surgery were randomly assigned to either ES with a stimulating catheter or ultrasound guidance with a nonstimulating catheter. The primary outcome was the catheter insertion duration (minutes) starting when the ultrasound transducer (ultrasound group) or catheter placement needle (stimulation group) first touched the patient and ending when the catheter placement needle was removed after catheter insertion. RESULTS: Perineural catheters placed with ultrasound guidance took a median (10th-90th percentile) of 9.0 (6.0-13.2) minutes compared with 15.0 (4.9-30.0) minutes for stimulation (P < .01). All ultrasound-guided catheters were successfully placed according to the protocol (n = 20) versus 70% in the stimulation group (n = 20; P < .01). All ultrasound-guided catheters resulted in a successful surgical block, whereas 2 catheters placed by stimulation failed to result in surgical anesthesia. Six catheters (30%) placed via stimulation resulted in vascular punctures compared with none in the ultrasound group (P < .01). Procedure-related pain scores were similar between groups (P = .34). CONCLUSIONS: Placement of infraclavicular perineural catheters takes less time, is more often successful, and results in fewer inadvertent vascular punctures when using ultrasound guidance compared with ES.

Ultrasound-guided perineural catheter and local anesthetic infusion in the perioperative management of pediatric limb salvage: a case report.

Local anesthetic perineural infusion has emerged as an effective analgesic technique in pediatric patients, but it can also complement surgical perioperative management in complex cases that require optimal tissue perfusion such as limb salvage. We report the successful use of brachial plexus perineural infusion in the care of a child following near-amputation of her dominant hand. An ultrasound-guided infraclavicular brachial plexus catheter was placed in the recovery room after complex reconstructive surgery and a continuous infusion of 0.2% ropivacaine maintained for 24 days. The resultant sympathectomy was integral to providing distal limb perfusion despite partial restenosis of the surgical revascularization.