Nerve Catheter Research Articles

Regionalanästhesie - Regionalanästhesie und Analgesie für die Kniegelenksendoprothetik

Postoperative analgesia for total knee replacement with a continuous nerve catheter is more effective than any other form of systemic analgesia. For complete analgesia a combined technique of a femoral with a proximal sciatic nerve block is recommended. An easy and reliable way to achieve this is a femoral or a fascia iliaca compartment block together with a subgluteal sciatic nerve block.

A Pilot Study on Continuous Femoral Perineural Catheter for Analgesia After Total Knee Arthroplasty: The Effect on Physical Rehabilitation and Outcomes

Two techniques of postoperative analgesia for primary total knee arthroplasty were compared retrospectively. Twenty-four patients received a femoral nerve catheter with continuous infusion of ropivacaine (FNC group), whereas 26 patients received intravenous (IV) opioids (IV opioid group). Pain and rehabilitation scores and hospital length of stay (LOS) were compared. On the first postoperative day, both groups reported similar pain scores. After 4 sessions of twice-daily rehabilitation, the FNC group used less IV patient-controlled opioids (29.1% vs 84.5%, P = .0001) and demonstrated better performance with knee flexion and mobility. Hospital LOS was significantly less in the FNC group (3.6 vs 4.2 days, P = .034). Femoral nerve catheters with continuous infusion of ropivacaine provide satisfactory analgesia, improve rehabilitation, and shorten hospital LOS.

A Comparison of Epidural Analgesia With Combined Continuous Femoral-Sciatic Nerve Blocks After Total Knee Replacement

Epidural analgesia remains the "gold standard" of pain relief after total knee replacement. However, peripheral nerve block is gaining popularity because the incidence of side effects may be reduced. Our study tests this postulate. Sixty patients were prospectively randomized to receive either epidural infusion or combined continuous femoral and sciatic nerve blocks. Ropivacaine 2 mg/mL plus sufentanil 1 mug/mL was given either epidurally or through the femoral nerve catheter, and ropivacaine 0.5 mg/mL was given through the sciatic nerve catheter using elastomeric infusers (delivering 5 mL/h for 55 h). The primary outcome measure was the total incidence of side effects (urinary retention and moderate to severe degrees of dizziness, pruritus, sedation, and nausea/vomiting on the first postoperative day). Intensity of motor blockade, pain at rest and on mobilization, and rehabilitation indices were also registered for 72 h. One or more side effects were present in 87% of patients in the epidural group whereas only 35% of patients in the femoral and sciatic block groups were affected on the first postoperative day (P = 0.0002). Motor blockade was more intense in the operated limb on the day of surgery and the first postoperative day in the peripheral nerve block group (P = 0.001), whereas the non-operated limb was more blocked in the epidural group on the day of surgery (P = 0.0003). Pain on mobilization was well controlled in both groups and there were no differences in the length of hospital stay. Rehabilitation indices were similar. The results demonstrate a reduced incidence of side effects in the femoral/sciatic nerve block group than in the epidural group on the first postoperative day.

Reduction of Verbal Pain Scores after Anterior Cruciate Ligament Reconstruction with 2-Day Continuous Femoral Nerve Block

Single-injection femoral nerve block analgesia and spinal anesthesia have been associated with fewer postoperative nursing interventions and successful same-day discharge after anterior cruciate ligament reconstruction. In the current study, the authors prospectively determined the effect of continuous femoral nerve block on a numeric rating scale (NRS) of pain intensity with movement for 7 postoperative days. Patients undergoing this surgery with no history of previous invasive surgery on the same knee were recruited for this study. After standardized spinal anesthesia, intravenous sedation, and perioperative multimodal analgesia, patients received a femoral nerve catheter with (1) saline bolus (30 ml) plus saline infusion (270 ml at 5 ml/h, placebo group); (2) levobupivacaine (0.25%) bolus with saline infusion (group I), or (3) levobupivacaine (0.25%) bolus and infusion (group II). Patients were surveyed preoperatively and on postoperative days 1-4 and 7 to determine NRS scores (scale 0-10). Data from 233 participants were analyzed. On days 1-2, 50% of placebo patients had NRS scores of 5 or above, whereas among group II patients, only 25% had scores of 5 or above (P < 0.001). In regression models for NRS scores during days 1-4, group II was the only factor predicting lower pain scores (odds ratios, 0.3-0.5; P = 0.001-0.03). Overall, patients with preoperative NRS scores greater than 2 were likely to report higher NRS scores during days 1-7 (odds ratios, 3.3-5.2; P < 0.001). Femoral nerve block catheters reliably keep NRS scores below the moderate-to-severe pain threshold for the first 4 days after anterior cruciate ligament reconstruction.

Effectiveness of 3-in-1 Continuous Femoral Block of Differing Concentrations Compared to Patient Controlled Intravenous Morphine for Post Total Knee Arthroplasty Analgesia and Knee Rehabilitation

We assessed the effectiveness of the 3-in-1 continuous femoral block as a form of postoperative pain relief for unilateral total knee arthroplasty (TKA). Sixty patients undergoing elective unilateral TKA under subarachnoid block were randomized into three groups. Postoperative analgesia was provided with a continuous 3-in-1 femoral nerve catheter with 0.15% ropivacaine in group A, a continuous 3-in-1 femoral nerve catheter with 0.2% ropivacaine in group B, or patient controlled intravenous morphine in group C (control group). Groups A and B received patient controlled intravenous morphine pumps for rescue analgesia. Patients in each group were followed for 72 hours postoperatively. Five patients were excluded after randomization. In the remaining 55 patients there was no statistical difference in pain score between the groups. Total morphine use was highest in group C (P < 0.05). No appreciable difference could be found with sensorimotor blockade, morphine usage and satisfaction scores when comparing groups A and B. Femoral catheter dislodgement rate was 7.9%. There was no statistical difference between the groups when comparing the day of first ambulation and the time to discharge from the hospital. Satisfaction scores were higher in group A (P = 0.028) and group B (P = 0.002) compared to group C. We conclude that a continuous 3-in-1 femoral nerve block with ropivacaine 0.15% or 0.2% for elective unilateral TKA has an opioid-sparing effect.

Does Continuous Peripheral Nerve Block Provide Superior Pain Control to Opioids? A Meta-Analysis

Although most randomized clinical trials conclude that the addition of continuous peripheral nerve blockade (CPNB) decreases postoperative pain and opioid-related side effects when compared with opioids, studies have included relatively small numbers of patients and the majority failed to show statistical significance during all time periods for reduced pain or side effects. We identified studies primarily by searching Ovid Medline (1966-May 21, 2004) for terms related to postoperative analgesia with CPNB and opioids. Each article from the final search was reviewed and data were extracted from tables, text, or extrapolated from figures as needed. Nineteen articles, enrolling 603 patients, met all inclusion criteria. Inclusion criteria were a clearly defined anesthetic technique (combined general/regional anesthesia, general anesthesia alone, peripheral nerve block), randomized trial, adult patient population (> or =18 yr old), CPNB (or analgesia) used postoperatively (intrapleural catheters were deemed not to be classified as a peripheral nerve catheter), and opioids administered for postoperative analgesia in groups not receiving peripheral nerve block. Perineural analgesia provided better postoperative analgesia compared with opioids (P < 0.001). This effect was seen for all time periods measured for both mean visual analog scale and maximum visual analog scale at 24 h (P < 0.001), 48 h (P < 0.001), and 72 h (mean visual analog scale only) (P < 0.001) postoperatively. Perineural catheters provided superior analgesia to opioids for all catheter locations and time periods (P < 0.05). Nausea/vomiting, sedation, and pruritus all occurred more commonly with opioid analgesia (P < 0.001). A reduction in opioid use was noted with perineural analgesia (P < 0.001). CPNB analgesia, regardless of catheter location, provided superior postoperative analgesia and fewer opioid-related side effects when compared with opioid analgesia.

Patient-Controlled Analgesia in the Management of Postoperative Pain

Patient-controlled analgesia (PCA) is a delivery system with which patients self-administer predetermined doses of analgesic medication to relieve their pain. Since its introduction in the early 1980s, the daily management of postoperative pain has been extensively optimised. The use of PCA in hospitals has been increasing because of its proven advantages over conventional intramuscular injections. These include improved pain relief, greater patient satisfaction, less sedation and fewer postoperative complications. All PCA modes contain the following variables: initial loading dose, demand dose, lockout interval, background infusion rate and 1-hour or 4-hour limits. Morphine is the most studied and most commonly used intravenous drug for PCA. In spite of the fact that it is the 'first choice' for PCA, other opioids have been successfully used for this option. The most observed adverse effects of opioid-based PCA are nausea and vomiting, pruritus, respiratory depression, sedation, confusion and urinary retention. Although intravenous PCA is the most studied route of PCA, alternative routes have extensively been described in the literature. PCA by means of peridural catheters and peripheral nerve catheters are the most studied. Recently, transdermal PCA has been described. The use of peripheral or neuraxial nerve blocks is recommended to avoid the so called opioid tolerance observed with the intravenous administration of opioids. Numerous studies have shown the superiority of epidural PCA to intravenous PCA. The beneficial postoperative effects of epidural analgesia are more apparent for high-risk patients or those undergoing higher risk procedures. PCA with peripheral nerve catheters results in increased postoperative analgesia and satisfaction for surgery on upper and lower extremities. Serious complications occur rarely with these catheters. With the introduction of an Acute Pain Service, management of postoperative pain can be improved. This will also help to minimise adverse effects related to PCA and to avoid lethal mishaps.

Postoperative Analgesia and Functional Recovery After Total-Knee Replacement: Comparison of a Continuous Posterior Lumbar Plexus (Psoas Compartment) Block, a Continuous Femoral Nerve Block, and the Combination of a Continuous Femoral and Sciatic Nerve Block

Continuous femoral nerve block is a well-accepted technique for regional analgesia after total-knee replacement. However, many patients still experience considerable pain at the popliteal space and at the medial aspect of the knee. The goal of this study is to evaluate whether a psoas compartment catheter provides better postoperative analgesia than a femoral nerve catheter does and whether it is as effective as the combination of a femoral and a sciatic nerve catheter and, thus, improves functional outcome. Ninety patients who underwent total-knee replacement under standardized general anesthesia participated in this prospective randomized study. Group FEM received a continuous femoral nerve block, group FEM/SCI received a combination of a femoral and a sciatic continuous nerve block, and group PSOAS received a continuous psoas compartment block. Patient-controlled analgesia with piritramide was available for 48 hours. Maximal bending and extending of the knee and walking distance was assessed during the first 7 days. A standardized telephone survey was conducted after 9 to 12 months to evaluate residual pain and functional outcome. Postoperative opioid consumption during 48 hours was significantly less in the FEM/SCI group (median: 18 mg; 25th/75th percentile: 6/40) compared with the FEM group (49 mg; 25/66) and the PSOAS group (44 mg; 30/62) (P =.002). Postoperative pain scores were not different, and no differences occurred with respect to short-term or long-term functional outcome. The FEM/SCI catheter is superior to FEM and PSOAS catheter with respect to reduced analgesic requirements after total-knee replacement, but functional outcome does not differ with those 3 continuous regional analgesia techniques.

Use of a stimulating catheter for total knee replacement surgery: preliminary results

There is continuing debate as to whether the use of electrical stimulation that aids in localizing nerves is also beneficial for optimizing placement of nerve catheters and lead to improved clinical outcomes, such as reductions in pain scores and opioid consumption. We undertook a retrospective, non-randomized comparison of stimulating and non-stimulating nerve catheters in 419 patients undergoing total knee replacement between December 2002 and July 2004. Before surgery, patients received sciatic and femoral nerve blocks with a catheter for the femoral nerve. In 159 patients a stimulating catheter system (Stimucath; Arrow International, Reading, PA, USA) and in 260 patients a non-stimulating catheter system (Contiplex; B. Braun, Melsungen, Germany) was used. After surgery, pain scores and morphine consumption were recorded at 4-h intervals until the first postoperative morning. In a subset of 85 patients, the postoperative evaluation period was lengthened to 3 days. Postoperative visual analogue scores (VAS) for pain were similar in the two groups during the first 24 h (P=0.305). In patients followed for 3 days, VAS scores did not differ on any of the days (P=0.427). Total morphine consumption did not differ on the first postoperative day (mean [95% CI]: stimulating, 12.4 [10.1-14.7] mg; non-stimulating 10.4 [8.9-11.8] mg; P=0.140) or on subsequent days. The practical advantages of the stimulating catheter, as reported by previous investigators, were not obvious in this clinical situation. In terms of outcome measures such as pain scores and morphine consumption, we found no significant differences between stimulating and non-stimulating catheters.

The Long Term Myotoxic Effects of Bupivacaine and Ropivacaine After Continuous Peripheral Nerve Blocks

Compared with bupivacaine, acute myotoxicity of ropivacaine is less severe. Thus, in this study we compared the long term myotoxic effects of both drugs in a clinically relevant setting. Femoral nerve catheters were inserted in anesthetized pigs, and either 20 mL of bupivacaine (5 mg/mL) or ropivacaine (7.5 mg/mL) was injected. Subsequently, bupivacaine (2.5 mg/mL) and ropivacaine (3.75 mg/mL) were continuously infused (8 mL/h) over 6 h. Control animals were treated with corresponding volumes of normal saline. After 7 and 28 days, respectively, muscle samples were dissected at the former injection sites, and histological patterns of muscle damage were blindly scored (0 = no damage to 3 = marked lesions/myonecrosis) and compared. No morphological tissue changes were detected in control animals. In the observed period, both local anesthetics induced morphologically identical patterns of calcific myonecrosis, formation of scar tissue, and a marked rate of fiber regeneration. However, bupivacaine's effects were constantly more pronounced than those of ropivacaine. These data show that both drugs induce irreversible skeletal muscle damage in a clinically relevant model, and confirm the exceeding rate of myotoxicity of bupivacaine. However, the clinical impact of these long term myotoxic effects still has to be assessed. In a period of 4 wk after peripheral nerve block, both long-acting local anesthetics, bupivacaine and ropivacaine, produced calcific myonecrosis suggestive of irreversible skeletal muscle damage. In comparison with ropivacaine, however, the extent of bupivacaine-induced muscle lesions was significantly larger.

Future of regional anaesthesia

The development and refinement of regional anaesthetic techniques for various types of surgery, mainly obstetric, ophthalmic and orthopaedic surgery, and of continuous regional analgesia continues. Suitable analgesic drug mixtures, and concentrations, will be further tested in order to find the ideal analgesic regimen for each type of surgery and for the individual patient. No new local anaesthetics or equipment for clinical use are expected in the near future. Improvement therefore depends much on how the anaesthesiologists use the present drugs, needles, nerve detection devices, catheters and pumps. During training in regional anaesthesia for the speciality of anaesthesiology and intensive care medicine, it may suffice to concentrate only on certain common techniques such as epidural block, spinal block, axillary brachial plexus block, intravenous regional anaesthesia and femoral nerve block. Rare regional anaesthetic blocks and invasive techniques should be mastered and taught by specially trained regional anaesthesiology experts. In chronic pain, regional anaesthetic blocks with local anesthetics are not expected to play any major therapeutic role. However, nerve blocks can be useful for diagnostic purposes and in order to facilitate rehabilitation in chronic pain syndromes.

Thoracic Epidural Versus Intercostal Nerve Catheter Plus Patient-Controlled Analgesia: A Randomized Study

Pain control is an important issue after thoracotomy. Ideal methods should have a high success rate, with easy implementation and minimal complications. Debate exists over the optimal pain control method. This randomized trial was designed to compare epidural (EPI) and intercostal nerve catheter with patient-controlled analgesia (ICN-PCA) for pain control after thoracotomy. The study included 124 randomized patients; 91 had sufficient data for analysis (44 EPI, 47 ICN-PCA). The primary endpoint was pain measurement using a composite of a visual analogue scale, numerical rating, and categorical rating. A second endpoint was the success rate of each method. Pulmonary function tests, antibiotics, intensive care unit (ICU), and hospital days, and use of nonprotocol pain medications were also compared. There were 12 pain observations per patient (90% completed on days 1 to 5). The pain composite revealed an average postoperative pain score of 2.4 on a scale from 0 (no pain) to 10 (worst pain). There was no difference between the groups. Failures of the planned method of analgesia included 9 in the EPI group and 4 in the ICN group (p = 0.23). Another 20 patients were excluded (no difference between groups) due to unsuspected mediastinal metastases precluding thoracotomy (n = 13), and other miscellaneous factors precluding follow-up (n = 7). The EPI group had an increased number of urinary catheter days (2.5 days vs 1.7, p = 0.002) and increased narcotic supplements (p = 0.03) compared with ICN. Mean ICU days (0.9) and hospital days (6.2) were similar for both groups, and there were no differences in arrhythmias, pneumonias, transfusions, and antibiotic use. Significant differences were seen (p = 0.001) between preoperative and postoperative pulmonary function tests in both groups. However, there were no differences in pulmonary function when the groups were compared with each other. Satisfactory pain control was achieved after thoracotomy using either EPI or ICN-PCA. The ICN-PCA achieved equivalent pain control compared with EPI, and was placed by the surgeon with no delays in surgery, and demonstrated a decreased requirement for Foley catheter duration.

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.

Anterior sciatic nerve block – new landmarks and clinical experience

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. 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. 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. Our landmarks for locating the sciatic nerve help to avoid bony contacts and thereby reduce pain during puncture. Our method reliably enabled catheter placement.

Risk factors for bacterial catheter colonization in regional anaesthesia

BackgroundAlthough several potential risk factors have been discussed, risk factors associated with bacterial colonization or even infection of catheters used for regional anaesthesia are not very well investigated.MethodsIn this prospective observational trial, 198 catheters at several anatomical sites where placed using a standardized technique. The site of insertion was then monitored daily for signs of infection (secretion at the insertion site, redness, swelling, or local pain). The catheters were removed when clinically indicated (no or moderate postoperative pain) or when signs of potential infection occurred. After sterile removal they were prospectively analyzed for colonization, defined as > 15 colony forming units.Results33 (16.7%) of all catheters were colonized, and 18 (9.1%) of these with additional signs of local inflammation. Two of these patients required antibiotic treatment due to superficial infections. Stepwise logistic regression analysis was used to identify factors associated with catheter colonization. Out of 26 potential factors, three came out as statistically significant. Catheter placement in the groin (odds-ratio and 95%-confidence interval: 3.4; 1.5–7.8), and repeated changing of the catheter dressing (odds-ratio: 2.1; 1.4–3.3 per removal) increased the risk for colonization, whereas systemic antibiotics administered postoperatively decreased it (odds ratio: 0.41; 0.12–1.0).ConclusionColonization of peripheral and epidural nerve catheter can only in part be predicted at the time of catheter insertion since two out of three relevant variables that significantly influence the risk can only be recorded postoperatively. Catheter localisation in the groin, removal of the dressing and omission of postoperative antibiotics were associated with, but were not necessarily causal for bacterial colonization. These factors might help to identify patients who are at increased risk for catheter colonization.

Continuous peripheral nerve blocks

Sophisticated regional anesthesia techniques have experienced substantial growth throughout the past 5 years for acute and chronic pain management. The recognition that regional anesthesia leads to superior postoperative outcomes in acute pain management and to an increased understanding of the pathogenesis of chronic pain has led to increased use of continuous peripheral nerve catheters. Furthermore, the availability of new equipment and techniques specifically designed to facilitate effective catheter placement has increased interest and adoption of peripheral nerve catheters to manage painful conditions. This has become particularly relevant as the scope of ambulatory surgery continues to grow. To maximize success rates with continuous peripheral nerve catheters, clinicians must be intimately aware of the pertinent regional anatomy and technical issues surrounding placement and maintenance of continuous nerve blockade. The recent development of outpatient infusion systems and novel anesthetics has been exciting and is likely to lead to an increase in the use of continuous peripheral catheter techniques. The consistent recognition that these techniques dramatically increase patient satisfaction should dictate an increasing presence in the field of pain management throughout the next several years.

Successful Removal of a Knotted Fascia Iliaca Catheter: Principles of Patient Positioning for Peripheral Nerve Catheter Extraction

Peripheral nerve catheters are typically advanced a substantial distance into a perineural sheath, theoretically increasing the risk of catheter knotting and kinking. In this case report, we describe successful removal of a knotted fascia iliaca catheter and discuss principles of nonsurgical catheter extraction. A 64-yr-old woman with bilateral coxarthrosis presented for total hip arthroplasty under combined general/regional anesthesia. A 20-gauge fascia iliaca catheter was inserted before surgery by using a loss-of-resistance "double pop" technique. The catheter was uneventfully advanced 10 cm past the needle tip. After injection of 30 mL of 0.5% bupivacaine with 1:200,000 epinephrine and 100 microg of clonidine, general anesthesia was induced. An infusion of 0.1% bupivacaine at 20 mL/h was initiated in the recovery room for postoperative analgesia. Approximately 48 h later, resistance was encountered during catheter removal. Catheter extraction was attempted by altering patient positioning, including the supine position during which the catheter placement had occurred. Successful catheter removal was achieved by decreasing tension on the fascia lata and fascia iliaca through flexion of the hip joint and by applying firm, steady traction. The catheter was removed intact with a knot approximately 2 cm from the distal tip. We conclude that the principles for removal of entrapped peripheral catheters are not well known and may differ from those for neuraxial catheters. Patient positioning to minimize pressure and tension on the perineural soft tissues may facilitate catheter removal.

Abstract 43 comparison of rehabilitation outcomes in patients with total knee arthroplasty utilizing postoperative continuous femoral nerve catheter analgesia versus intravenous patient controlled analgesia: a retrospective study. Kevin E. Brueilly, MPT (St. Luke’s Hosp/Mayo Clin, Jacksonville, FL); Martin L. De Ruyter, MD; Roy A. Greengrass, MD. Brueilly is now affiliated with Texas Tech Univ Sch Allied Health Sci., e-mail: kevin.brueilly@ttuhsc.edu

Abstract 43 comparison of rehabilitation outcomes in patients with total knee arthroplasty utilizing postoperative continuous femoral nerve catheter analgesia versus intravenous patient controlled analgesia: a retrospective study. Kevin E. Brueilly, MPT (St. Luke’s Hosp/Mayo Clin, Jacksonville, FL); Martin L. De Ruyter, MD; Roy A. Greengrass, MD. Brueilly is now affiliated with Texas Tech Univ Sch Allied Health Sci., e-mail: kevin.brueilly@ttuhsc.edu

Prospective comparison of continuous femoral nerve block with nonstimulating catheter placement versus stimulating catheter-guided perineural placement in volunteers

Background and objectives Stimulating catheter-guided perineural placement may potentially increase the success rate and quality of continuous femoral nerve block as compared with a nonstimulating catheter technique. These hypotheses have not been rigorously tested. Methods Twenty volunteers underwent placement of bilateral femoral nerve catheters in this prospective, randomized, double-blind study. For each side, a stimulating needle was advanced until quadriceps contractions were obtained at ≤0.5 mA. On one side, a stimulating catheter was advanced 4 to 5 cm beyond the needle tip while eliciting quadriceps contractions via the catheter. If quadriceps contractions decreased or disappeared, the catheter position was adjusted until quadriceps contractions could be elicited at ≤0.5 mA. On the contralateral side, an identical catheter was advanced 4 to 5 cm beyond the needle tip without attempts to elicit quadriceps contractions via the catheter. After bolus injection of 10 mL lidocaine 1%, ropivacaine 0.2% at 10 mL/h was continuously infused through both catheters for 4 hours. Success of femoral block was defined as loss of sensation to cold and pinprick stimuli. Quality of successful block was determined by tolerance to transcutaneous electrical stimulation and force dynamometry of quadriceps strength. Results Block success was 100% via the stimulating catheters versus 85% via the nonstimulating catheters ( P = .07). Overall tolerance to transcutaneous electrical stimulation ( P = .009) and overall depth of motor block ( P = .03) was significantly higher in the stimulating catheter-guided femoral nerve blocks. Conclusions In this volunteer study, there was no statistically significant difference in block success between the two techniques. However, stimulating catheter-guided placement provided an increased overall quality of continuous femoral perineural blockade. Further studies are needed to verify these observations in the clinical setting.

Clinical evaluation of a modified posterior anatomical approach to performing the popliteal block

Background Tibial and common peroneal nerves can be blocked by the posterior approach to the popliteal fossa. Techniques using fixed measured distances between knee skin crease and puncture point have been described. We report on an approach that is based on manual identification of the apex of the popliteal fossa. Methods Five-hundred patients undergoing surgery of ankle or foot were prospectively included. The apex of the popliteal fossa (determined by the crossing point of the biceps femoris and the semitendinosus and semimembranosus muscles) was assessed by manual palpation. The puncture point was 0.5 cm below the apex, on the medial side of the biceps femoris muscle. When indicated for postoperative analgesia, a perineural catheter was placed. We assessed success rate, number of attempts, the distance between knee skin crease and the apex of the popliteal fossa, nerve depth, and acute and late complications. Results Block success rate was 94% and 92% when the block was performed through the needle and the catheter, respectively. Inversion was the motor response with the highest success rate. The first attempt was successful in 97.5% of the patients. Mean depth of the nerve was 4.5 cm (range, 2.0 to 7.0 cm) and mean knee skin crease to apex of popliteal fossa distance was 9 cm (range, 7.0 to 12.0 cm). Nine patients (2%) had acute complications. There were no technical problems associated with the perineural nerve catheter. After 12 weeks, no late complications were observed. Conclusions The modified posterior anatomical approach for popliteal sciatic nerve block is easy to perform, has a high success rate, and has a low complication rate. The location of the needle insertion point is assessed without any measurement, thus avoiding inaccuracies caused by repeated skin-distance measurements.