Continuous sciatic nerve infusion: Expanded case report describing a new approach

Background and Objectives. Severe pain following extensive reconstructive foot surgery is difficult to manage effectively. Sciatic nerve block provides excellent analgesia for a limited duration. I wanted to determine an approach to sciatic nerve block enabling an infusion of a local anesthetic for a prolonged period without loss of efficacy due to catheter displacement. Methods. Seventy-six consecutive sciatic nerve catheter placements—in 73 patients undergoing reconstructive foot surgery—were performed by four different approaches. Soft epidural catheters were found to be unsatisfactory—both for placement and for prolonged infusion. A firmer catheter, also capable of “through the catheter” nerve stimulation, was developed and proved to be satisfactory on both counts. Traditional approaches proved satisfactory for identifying the nerve but were unsatisfactory for prolonged infusion. A unique “in line” approach was developed to enable the insertion of the catheter along the course of the sciatic nerve, thus maintaining position for prolonged infusions. Results. According to predetermined criteria for success, only 64% of placements using traditional epidural catheters were successful, whereas the firmer catheter with “through the catheter” nerve stimulation was successful in 95% of placements. Conclusions. The described “in line” technique of continuous sciatic nerve infusion of a local anesthetic solution gives prolonged and effective analgesia following foot surgery.     

Ultrasound-guided subgluteal sciatic nerve blocks with stimulating catheters in children: a descriptive study

We describe our clinical experience of combining ultrasound guidance and nerve stimulation for the insertion of subgluteal sciatic catheters in children. Ten children scheduled for lower limb surgery with a combined general anesthetic and a subgluteal sciatic catheter placement for both operative anesthesia and postoperative pain relief were studied. Under ultrasonographic guidance the sciatic catheter was placed using an 17-gauge 50-mm Arrow continuous peripheral nerve block needle and a 19-gauge stimulating catheter (Stimucath). The minimal electrical current required for muscle contraction on the stimulating needle and catheter differed widely among patients. Based on the visualization of the spread of local anesthetic during injection through the catheter, a successful prediction for the sciatic block was made in all patients. All catheters were successfully placed and provided excellent postoperative pain relief without complications.     

Epidural catheter-induced paresthesia accompanied by changes in skin color and temperature in an obstetric patient

Placement of epidural catheters for labor analgesia is a common procedure that has become more popular in recent years. However, this procedure can often cause paresthesia, which is typically characterized as a transient and intense burning pain radiating to the hip or leg. In this case report, we describe a patient who had persistent paresthesia in her right foot caused by an indwelling epidural catheter, which was successfully relieved following a partial withdrawal of the epidural catheter. More interestingly, we also observed dramatic changes in skin color and temperature (cold and pale) on her right foot that was well correlated both in time and location with the epidural-induced paresthesia. This cold and pale skin on the right foot represents a localized sympathetic discharge associated with the epidural-induced paresthesia, a phenomenon that has not previously been described. Based on the location of the paresthesia and the pathway of the sympathetic nerve fibers, it is unlikely that this localized sympathetic discharge was due to a direct irritation of the preganglionic sympathetic fibers in the spinal nerve roots by the epidural catheter and thus, a spinal reflex was probably involved. This phenomenon provided us with additional clinical evidence of nerve root irritation, which prompted us to act quickly, and resulted in a favorable outcome.     

Continuous lateral popliteal block with stimulating catheters

Foot surgery often induces severe postoperative pain. Sciatic nerve block is a good alternative for its treatment. We report two cases of continuous lateral popliteal sciatic nerve block using two different stimulating catheters. The lateral approach may offer some advantages. Stimulating catheters may be useful to verify correct catheter tip positioning. This technique seem to be easy to use and provided excellent pain relief.     

Feasibility and efficacy of placement of continuous sciatic perineural catheters solely under ultrasound guidance in children: a descriptive study

Background: Placement of sciatic catheters with ultrasound and stimulating catheters is known. Literature regarding catheter placements with only ultrasound is limited. We aimed to investigate the feasibility of performing continuous sciatic nerve block exclusively with ultrasound guidance and minimal equipment. Method: Forty ASA 1 and 2 patients aged 8 months–10 years posted for congenital talipoequinovarus surgery were included in the study. Continuous sciatic catheters were placed under ultrasound guidance with 18‐ gauge Tuohy needle at the infragluteal fold. Then, 0.25% of bupivacaine 0.5 ml·kg^?1 bolus was injected followed by continuous infusion later. Half the volume of the drug was injected prior to catheter insertion to improve visibility. The sciatic nerve, needle tip and shaft, catheter tip and the drug spread were visualized. The efficacy of the block intraoperatively and postoperatively was evaluated. Results: The sciatic nerve, needle shaft, and tip were well visualized in all 40 patients. The catheter tip was seen in 72.5% of patients. The effect of block was complete intraoperatively and postoperatively. Clinically significant complications were absent. Conclusion: We conclude that in children, continuous sciatic catheters can be accurately and efficaciously placed with minimal equipment with ultrasound alone.     

Resection, rotationplasty, and femoropelvic arthrodesis in severe congenital femoral deficiency. A report of the surgical technique and three cases

BACKGROUND: The major problems associated with severe congenital deficiency of the femur are an unstable hip joint and a femur that is more than 50% shorter than the contralateral, normal femur. The usual treatment of these extreme cases of congenital femoral deficiency is a Syme or Boyd amputation when the child begins to walk. A knee fusion is done when the child is older, and the patient functions as an above-the-knee amputee. Rotationplasty has been described as an alternative treatment that allows the patient to function as a below-the-knee amputee. None of the currently described types of rotationplasty address the problem of the unstable hip. METHODS: Three patients with severe congenital femoral deficiency underwent a unique single-stage reconstruction. In this procedure, the limb is completely detached except for the sciatic nerve and the femoral vessels. The proximal part of the dysplastic femur and some muscles are resected. The residual limb is externally rotated 180 degrees and the rotated distal part of the femur is fused to the pelvis. All of the muscles distal to the knee remain undisturbed. RESULTS: The anatomical knee in its rotated position functioned as a hip with flexion and extension, and the femoropelvic arthrodesis provided a more stable support. The rotated ankle acted as a knee, and the patients functioned as below-the-knee amputees. The duration of follow-up of these three patients was eight, six, and four years. Active hip flexion was 10 degrees to 70 degrees , 10 degrees to 90 degrees , and 0 degrees to 80 degrees , and active knee flexion was 900 and 95 . The patients' gait continued to improve as they matured. CONCLUSIONS: The femoropelvic arthrodesis provides a stable hip. Since the muscles distal to the knee are not disturbed, the problem of derotation of the limb, which is often seen following the Van Nes rotationplasty, is not seen after this operation.     

Using stimulating catheters for continuous sciatic nerve block shortens onset time of surgical block and minimizes postoperative consumption of pain medication after halux valgus repair as compared with conventional nonstimulating catheters

We prospectively tested the hypothesis that the use of a stimulating catheter improves the efficacy of continuous posterior popliteal sciatic nerve block in 100 randomized patients scheduled for elective orthopedic foot surgery. After eliciting a sciatic mediated muscular twitch at < or = 0.5 mA nerve stimulation output, the perineural catheter was advanced 2-4 cm beyond the tip of the introducer either blindly (Group C; n = 50) or stimulating via the catheter (Group S; n = 50). A bolus dose of 25 mL of 1.5% mepivacaine was followed by a postoperative patient-controlled infusion of 0.2% ropivacaine (basal infusion: 3 mL/h; incremental dose: 5 mL; lockout time: 30 min). Propacetamol 2 g IV was administered every 8 h, and opioid rescue analgesia was available if required. Catheter placement required 7 +/- 2 min in Group S and 5 +/- 2 min in Group C (P = 0.056). A significantly shorter onset time of both sensory and motor blocks was noted in Group S. No difference in quality of pain relief at rest and during motion was reported between the groups. Median (range) local anesthetic consumption during the first 48 h after surgery was 239 mL (175-519 mL) and 322 mL (184-508 mL) in Groups S and C, respectively (P = 0.002). Rescue opioid analgesia was required by 12 (25%) and 28 (58%) patients in Groups S and C, respectively (P = 0.002). We conclude that the use of a stimulating catheter results in shorter onset time of posterior popliteal sciatic nerve block, similar pain relief with reduced postoperative consumption of local anesthetic solution, and less rescue opioid consumption. IMPLICATIONS: This prospective, randomized, blind investigation demonstrated that the use of a stimulating catheter for continuous posterior popliteal sciatic nerve block resulted in shorter onset time of sensory and motor blocks and less local anesthetic consumption and need for rescue pain medication after elective orthopedic foot surgery compared with blind catheter advancement.     

Does femoral nerve catheter placement with stimulating catheters improve effective placement? A randomized, controlled, and observer-blinded trial

Continuous peripheral nerve blocks offer the benefit of extended postoperative analgesia and accelerated functional recovery after major knee surgery. Conventional nerve localization is performed over a stimulating needle followed by blind insertion of the peripheral catheter. Correct catheter placement is confirmed by testing for satisfactory analgesia. Stimulating catheters offer the advantage of verifying correct placement close to the nerve during catheter placement. The aim of this randomized trial was to determine whether accurate catheter positioning under continuous stimulation accelerates the onset of sensory and motor block, improves the quality of postoperative analgesia, and enhances functional recovery. We compared femoral nerve catheters inserted under continuous stimulation with catheters that were placed using the conventional technique of blind advancement in 81 patients undergoing major knee surgery. Time of catheter placement was similar in both groups with 4 min (3/7.3; median, 25th/75th percentile) in the conventional group and 5 min (4/8.8) in the stimulating catheter group. In both groups, 42% of the catheters could be correctly placed (motor response of the patella with a current < or =0.5 mA) at first attempt. In 22 patients (58%) of the stimulating catheter group, the catheter had to be redirected 1-20 times, including 2 that could not be correctly placed within 20 min. The onset time of sensory and motor block was almost similar in both groups. There were no differences in the postoperative IV opioid consumption, and visual analog scale pain scores at rest and movement, or maximal bending and stretching of the knee joint during the 5 days after surgery. We conclude that with continuous femoral nerve blocks, blind catheter advancement is as effective as the stimulating catheter technique with respect to onset time of sensory and motor block as well as for postoperative pain reduction and functional outcome.     

Behandlung ischämischer Schmerzen der unteren Extremität durch repetitive Blockade des N. ischiadicus

In 70 patients a catheter was implanted in the popliteal fossa for repetitive block of the sciatic nerve in order to treat ischemic pain of the leg. At variable, individually determined time intervals of 4 – 12 h doses of 10 ml bupivacaine 0.25% or 0.5% were administered to 66 patients. In 4 patients a higher volume was injected. Good or excellent analgesia was obtained in 93%. Motoric deficits were seen in 2 of 3 patients. Improvement in perfusion caused by the blocking of sympathetic fibers was noticed in 5 of 17 patients. Technical complications occurred more often than with epidural regional techniques. The block of the popliteal sciatic nerve is of low risk and easy to perform. It is an effective alternative for symptomatic treatment of ischemic pain of the foot and lower leg.     

Three‐dimensional ultrasound‐assisted popliteal catheter placement revealing aberrant anatomy: implications for block failure

Background: The current means of introducing continuous sciatic catheters include nerve stimulation, with or without catheter stimulation techniques. More recently, ultrasound has been utilized to facilitate catheter placement. Methods: This case represents a stimulating catheter‐guided continuous block facilitated by three‐dimensional ultrasound, which revealed aberrant anatomy with proximal and wide bifurcation of the sciatic nerve with implications for block failure. Results: Before ultrasound imaging secondary failures were attributed to catheter misplacement or dislodgement. Conclusion: Because of this case observation, our current practice is to use ultrasound confirmation of the bifurcation of the nerve of all popliteal catheter placements, particularly catheters placed in patients having ambulatory procedures to prevent secondary failure of catheters at home.     

Severe phantom leg pain in an amputee after lumbar plexus block

OBJECTIVES: To describe the onset of phantom leg pain in an amputee with the performance of a lumbar plexus block and the subsequent alleviation after the performance of a sciatic nerve block. CASE REPORT: A 72-year-old American Society of Anesthesiologists physical status III woman presented for left total hip arthroplasty. Her history was significant for a left below the knee amputation. Since the amputation she had suffered from intermittent phantom leg pain. A lumbar plexus block was performed for postoperative pain management. After the lumbar plexus block, the patient experienced severe pain radiating to the left phantom foot. Because of the severity of the phantom pain, a sciatic nerve block was performed. The phantom leg pain resolved within 5 minutes. The intraoperative care under general anesthesia was uneventful. After surgery the patient had continued blockade in both nerve distributions with excellent analgesia. Full recovery of the lumbar plexus and sciatic nerve function was present on the first postoperative day. CONCLUSION: The temporal relationship between the onset of the phantom leg pain and the lumbar plexus block suggests a causal relationship. In this case, it appears that ongoing peripheral input from the lumbar plexus may have been sufficient for the tonic inhibition of phantom pain in the sciatic distribution. The immediate reactivation of the phantom pain and its subsequent relief suggests dynamic processing of peripheral inputs by central neurons, which apparently is rapid and reversible in some cases of phantom pain.     

Long current impulses may be required for nerve stimulation in patients with ischemic pain

Purpose

To report on the efficacy of peripheral plexus catheters in the treatment of ischemic pain in spite of nerve stimulation with long current impulses.

Clinical features

Tw o patients with severe neuropathic ischemic foot pain are described. A 56-yr-old man with diabetes, renal failure, and autonomic neuropathy presented with severe ischemic foot pain. Opioids produced excess sedation and hypotension. A 62-yr-old woman was admitted after femoralpopliteal bypass and developed a reperfusion pain syndrome not relieved with opioids, gabapentin, amitryptiline, and clonidine. In both patients, a sciatic plexus catheter was placed with resolution of pain. Conventional nerve stimulation, which uses a pulse duration of 0.1 msec, did not result in muscle contraction. However, by using a nerve stimulator capable of delivering a 1.0 msec impulse duration, a muscle twitch or paresthesia endpoint ensued allowing for successful catheter placement.

Conclusion

Peripheral plexus catheters provide a safe alternative to systemic analgesics for pain relief in patients with ischemic foot pain. However, conventional nerve stimulation techniques may not elicit a motor response in patients with underlying neuropathy, and the use of nerve stimulators capable of delivering long current impulses is recommended.     

Anterior sciatic nerve block--new landmarks and clinical experience

BACKGROUND: Anterior sciatic nerve blocks can be complicated by several problems. Pain can be caused by bony contacts and, in obese patients, identification of the landmarks is frequently difficult. METHODS: In a first step, 100 normal anterior-posterior pelvic X-rays were analyzed. The landmarks of the classical anterior approach were drawn on these X-rays and assessed for their sufficiency. Then, in a prospective case study, 200 consecutive patients undergoing total knee replacement were investigated. These patients received femoral and sciatic nerve catheters for postoperative pain management. Using modified anatomical landmarks, sciatic nerve catheters were inserted 5 cm distal from the insertion site of the femoral nerve block perpendicularly in the midline of the lower extremity. This midline connected the insertion site of the femoral nerve catheter to the midpoint between the medial and lateral epicondyle. Correct catheter positioning was verified by magnetic resonance imaging (MRI) in six patients. RESULTS: Evaluation of pelvic X-rays showed that puncture following the classical landmarks pointed in 51% at the lesser trochanter, in 5% medial to the lesser trochanter and in 42% directly at the femur. In the latter patients, location of the sciatic nerve would have been difficult or even impossible. Using our modified anterior approach, the sciatic nerve could be blocked in 196 patients (98%). In nine patients (4.5%) blockade of the posterior femoral cutaneous nerve failed. Vascular puncture happened in 10 (5%) and bony contact in 35 patients (17.5%). Median puncturing depth was 9.5 (7.5-14) cm. Correct sciatic nerve catheter positioning was verified in all patients who underwent MRI. CONCLUSION: Our landmarks for locating the sciatic nerve help to avoid bony contacts and thereby reduce pain during puncture. Our method reliably enabled catheter placement.     

Postoperative pain control using epidural catheters after anterior spinal fusion for adolescent scoliosis

STUDY DESIGN: A prospective review of patients undergoing epidural catheter placement after anterior spinal fusion and instrumentation for adolescent scoliosis was performed. Data were collected using visual analog pain scores reflecting the patients' perception of their pain control. OBJECTIVES: To present the authors' technique for epidural catheter placement and dosing protocol, and to demonstrate the results from postoperative pain control after anterior spinal instrumented fusion for 10 consecutive patients. SUMMARY OF BACKGROUND DATA: The literature regarding the benefits of epidural catheters after spinal surgery is contradictory, even with controlled studies comparing epidural catheters with intravenous morphine patient-controlled anesthesia. The authors believe that this lack of consensus stems from varied epidural dosing protocols and techniques in catheter placement, which they have witnessed anecdotally at their own institution. This prompted the authors to develop and refine a standardized dosing and catheter placement protocol for pain control after spinal surgery. METHODS: Epidural catheters were placed intraoperatively before wound closure, then removed on postoperative Day 5. Dosing consisted of fentanyl (1 microg/kg) and hydromorphone (5 microg/kg) diluted in preservative-free saline (0.2 mL/kg). After surgery, dosing consisted of 0.1% ropivacaine and hydromorphone (10 microg/ml) continuously infused at 0.2 mL/kg/hour. Postoperative pain control was assessed on each postoperative day using a visual analog pain scale with choices ranging from 0 to 10. RESULTS: The arithmetic mean of the median pain scores after surgery was 2.1. The mean of the maximum pain scores for the 5 days was 4.1. Three patients required an epidural bolus and a 20% increase in the epidural infusion rate. One patient was judged to be excessively sleepy, so the epidural infusion rate was decreased by 20%. Pruritus requiring diphenhydramine developed in three patients. No other adverse effects related to epidural analgesia were noted. No catheters were accidentally pulled out or disconnected. CONCLUSION: By following the dosing protocol described, epidural catheters can be used safely and effectively to control postoperative pain after anterior instrumentation and spinal fusion for adolescent scoliosis.     

The impact of regional anaesthesia on outcome: a patient's perspective

Peripheral nerve catheters are being used increasingly to manage acute pain. Whilst acknowledged as effective, their broader implications for patient outcome are less clear. In this case report, we describe the way in which not only was the pain management of an ischaemic leg successful via a sciatic nerve catheter, but decision-making around this strategy affected outcome.     

Continuous sciatic block for leg and foot surgery in 160 children

BACKGROUND: The aim of this study was to assess the safety and efficacy of continuous sciatic block for lower limb surgery in children. METHODS: A total of 160 pediatric patients aged 4 months to 12 years weighing 3.5-50 kg, were given continuous sciatic block plus single shot 3-in-1 block for leg and foot surgery. After general anesthesia, the sciatic nerve was located by using loss of resistance to saline by the mid-thigh approach. An 18 gauge epidural needle was introduced at the junction of the proximal two-third with the distal one-third of a line extending from the apex of popliteal triangle to the midpoint of the line joining the greater trochanter and the ischial tuberosity. A 20 g catheter was threaded through the needle for 5-10 cm and 0.25% bupivacaine 0.75 ml.kg(-1) was injected. A single shot 3-in-1 block was also given to facilitate the use of a tourniquet with 0.25% bupivacaine 0.25 ml. In 20 patients a nerve stimulator was used in addition to loss of resistance. The intraoperative sedation comprised propofol and ketamine infusions and 50% nitrous oxide in oxygen by LMA. RESULTS: Eight-two percent of patients showed no response to surgery; 14% patients showed some response to the medial incision over the ankle and needed additional bolus doses of ketamine and propofol. Block was considered to have failed in 4% who required an increase in propofol and ketamine infusions. A total of 154 patients had good postoperative pain relief for 72 h with continuous infusion of 0.05% bupivacaine. The other six were given oral codeine and diclofenac. There were no complications attributable to sciatic block in any patient. CONCLUSIONS: Sciatic block with a single shot 3-in-1 block for tourniquet pain and light general anesthesia provides good intraoperative conditions for leg and foot surgery and adequate postoperative pain relief. Additional sedation to minimize the discomfort of a cast may be a consideration in the first 24 h.     

Free microvascular rotationplasty with nerve repair for rhabdomyosarcoma in a 18‐month‐old patient

Rotationplasty is a limb‐sparing surgical option in lower limb malignancies. Sciatic or tibial nerve encasement has been considered an absolute contraindication to this procedure. We report a case of an 18‐month‐old girl with a rhabdomyosarcoma that affected the leg and popliteal fossa, with neurovascular involvement. Knee and proximal leg intercalary resection was performed followed by reconstruction with free microvascular rotationplasty and neurorraphy from tibial division of sciatic nerve to sural and tibial nerves, and from saphenous nerve to superficial peroneal nerve. Postoperative course was uneventful and ambulation with a provisional prosthesis was restarted during the sixth week after surgery. Bone consolidation was observed after two months. Eighteen months later, the patient had a good gait pattern with a below‐knee prosthesis and had recovered sensation in the whole foot and ankle area. This case shows that rotationplasty with nerve repair may provide a sensate stump, which is vital for successful prosthetic adaptation. We believe it may be considered as an alternative to above‐knee amputation in tumors with sciatic involvement.     

Continuous subgluteus sciatic nerve block after orthopedic foot and ankle surgery: comparison of two infusion techniques

BACKGROUND AND OBJECTIVE: To compare continuous infusion or a patient-controlled technique for postoperative analgesia after foot surgery, using a new subgluteus approach for continuous sciatic nerve block. METHODS: Fifty healthy patients, undergoing orthopedic foot surgery, received a continuous sciatic nerve block using a new subgluteus approach. All blocks were placed with the aid of a nerve stimulator using a 10-cm, 18-gauge insulated Tuohy needle. After either plantar flexion or dorsiflexion of the operated foot was elicited at < or = 0.5 mA, 20 mL of 0.75% ropivacaine was injected incrementally using repeated aspiration tests, then followed by the introduction of a 20-gauge epidural catheter. Postoperatively, 0.2% ropivacaine was infused with either a 10 mL/h continuous infusion (group Continuous, n = 25) or with a 5 mL/h basal rate with 5 mL bolus every 60 minutes (group patient-controlled analgesia [PCA], n = 25). Intraoperative analgesic supplementation, as well as postoperative pain relief, morphine consumption, incidence of complication, and patient satisfaction were recorded by an observer unaware of group assignment. RESULTS: The sciatic catheter was successfully placed in all patients. Intravenous fentanyl supplementation (dose range, 50 to 150 microg) was required in 4 patients in each group, but no patient required general anesthesia. Catheter dislocation was reported in 2 patients (4%). The quality of pain relief was good in both groups, and none experienced complications. Nine patients of the Continuous group (37%) and 7 patients of the PCA group (29%) required rescue morphine analgesia because of pain in the femoral dermatomes (P =.76). Ropivacaine consumption was 240 mL in the Continuous group (range, 200 to 240 mL) and 140 mL in the PCA group (range, 120 to 290 mL) (P =.0005). Patient acceptance was good in both groups. CONCLUSIONS: The continuous subgluteus sciatic nerve block represents an easy and reliable option for postoperative analgesia after foot surgery; using a patient controlled rather than a continuous infusion technique reduces the consumption of local anesthetic solution without affecting the quality of pain relief.     

Double epidural catheter with ropivacaine versus intravenous morphine: a comparison for postoperative analgesia after scoliosis correction surgery

BACKGROUND: Major spine surgery with a dorsal or ventrodorsal approach causes severe postoperative pain. The use of continuous epidural analgesia through one or two epidural catheters placed intraoperatively by the surgeon has been shown to provide efficient postoperative pain control. In this prospective unblinded study, the authors compared the efficacy of continuous intravenous morphine with a continuous double epidural catheter technique with ropivacaine after scoliosis correction. METHODS: Thirty patients with American Society of Anesthesiology physical status I-III were prospectively randomized to either the morphine group or the epidural group. At the end of surgery, patients in the epidural group received two epidural catheters placed by the surgeon, one directed cephalad and one caudally. Correct placement was checked radiographically. Postoperative analgesia until the first postoperative morning was performed with remifentanil target-control infusion for all patients. From that time remifentanil was stopped and continuous intravenous analgesia with morphine or double epidural analgesia with ropivacaine 0.3% was initiated (T0 = beginning of study). Pain at rest and pain in motion (using a visual analog scale from 0-100), the amount of rescue analgesics, sensory level, motor blockade, postoperative nausea and vomiting, and pruritus were assessed every 6 h and bowel function was assessed every 12 h until T72 (end of study). Two days later, patient satisfaction was assessed. RESULTS: Pain scores at rest were significantly decreased in the epidural group at all time points except at T12, T60, and T72. Pain scores in motion were significantly decreased in the epidural group at T24, T48, and T72. Bowel activity was significantly better in the epidural group at T24, T36, T48, and T60. Postoperative nausea and vomiting and pruritus occurred significantly less frequently in the epidural group. No complications related to the epidural catheter occurred. CONCLUSIONS: Both methods provide efficient postoperative analgesia. However, double epidural catheter technique provides better postoperative analgesia, earlier recovery of bowel function, fewer side effects, and a higher patient satisfaction.     

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.