Department of Anesthesiology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA

The popliteal fossa nerve block (PFNB) offers numerous advantages that make it a suitable anesthetic technique for foot and ankle surgery. In this retrospective study, we investigated the acute and long-term safety and efficacy of this relatively underutilized anesthetic technique for foot and ankle surgery. A review of 834 patients who underwent foot and/or ankle surgery by the coauthor (NAA) was conducted. Four hundred sixty-seven patients received a PFNB with the aid of a peripheral nerve stimulator. Variables assessed included the quality of surgical anesthesia, postoperative analgesia and the acute and long-term incidence of postoperative neuralgia and neuropraxia. The PFNBs were performed by anesthesiologists with various levels of training at a tertiary care hospital and all were supplemented with a saphenous nerve block. The PFNB was successful as the sole anesthetic technique in 79% of the cases; 18% were converted to general anesthesia and 3% required augmentation with local anesthetic. There were no complications associated with the PFNB. There were no incidents of postoperative neuralgia or neuropraxia. Only 12% of patients with a successful block required analgesics in the PACU, while 60% of patients with a failed block required systemic analgesics for surgical site pain (p < 0.01). These results suggest that the performance of the PFNB with the guidance of a peripheral nerve stimulator is a safe and effective anesthetic technique for foot and ankle surgery.

PMID: 12043982 - www.pubmed.com

St. Luke's-Roosevelt Hospital Center, College of Physicians and Surgeons, Columbia University, New York, NY 10025, USA. ah149@columbia.edu

The classical approach to sciatic nerve block in the popliteal fossa (popliteal block) often requires multiple attempts to localize the sciatic nerve. Recently, it has been suggested that an intertendinous approach to popliteal block may result in a more consistent localization of the sciatic nerve. In the current study, we compared anatomical landmarks for the intertendinous and classical approaches to popliteal block with respect to the accuracy in localizing the sciatic nerve using magnetic resonance imaging simulation. Two anesthesiologists experienced in popliteal block drew landmarks for the intertendinous and classical approaches on 10 volunteers; a 1.5 Tesla superconducting magnet was used to obtain simultaneous, 10-mm thick, fast-spin echo proton density transverse axial sequences of the lower extremities. Using these acquired images, the two approaches were simulated off-line using previously identified landmarks. The spatial relationships of the simulated needle paths to the nerves and vessels in the popliteal fossa, as well as other relevant structures, were measured and compared. Simulation of the intertendinous approach to popliteal block resulted in needle-to-sciatic nerve contact in 14 legs (70%) versus 5 legs (25%) when the classical approach was used (P < 0.05). We conclude that the intertendinous approach might result in a more consistent localization of the sciatic nerve and may decrease the risk of sciatic vessel puncture. IMPLICATIONS: A simulation of popliteal block using magnetic resonance imaging in volunteers suggests that using tendons of the hamstring muscles as the anatomical landmarks yields a more consistent localization of the sciatic nerve.

PMID: 11973213 - www.pubmed.com

The sciatic nerve (SN) originates from the L4-S3 roots in the form of two nerve trunks: the tibial nerve (TN) and the common peroneal nerve (CPN). The TN and CPN are encompassed by a single epineural sheath and eventually separate (divide) in the popliteal fossa. This division of the SN occurs at a variable level above the knee and may account for frequent failures reported with the popliteal block. We studied the level of division of the SN in the popliteal fossa and its relationship to the common epineural sheath of the SN. The level of division of the SN sheath into TN and CPN above the knee was measured in 28 cadaver leg specimens. The SN was invariably formed of independent trunks (TN and CPN) encompassed in one common epineural sheath. The SN divided at a mean distance of 60.5 27.0 mm (range 0 to 115 mm) above the popliteal fossa crease. We conclude that the TN and CPN leave the common SN sheath at variable distances from the popliteal crease. This finding and the relationship of the TN and CPN sheaths may have significant implications for popliteal block. Implications: When performing popliteal block, insertion of the needle at 100 mm above the popliteal crease is more likely to result in placement of the needle proximal to the division of the sciatic nerve than placement at 50 or 70 mm, according to the classical teaching.

PMID: 11133630 - www.pubmed.com

Foot and ankle operations are being performed with greater frequency as outpatient procedures. Although the surgical procedure remains the same whether the operation is done in an inpatient or an outpatient setting, the anesthesia and postoperative analgesia are greatly affected when patients must be discharged soon after their operation. We have evaluated a regional anesthetic technique which blocks the sciatic nerve in the popliteal fossa and the saphenous nerve block at the knee. This was the sole anesthetic technique for both the operation and the immediate postoperative period. This technique appears to have several advantages: 1) Excellent anesthesia during the operation and for about ten hours postoperatively; 2) Use of a proximal calf tourniquet, and 3) Absence of systemic or local complications as might be seen with general, spinal or epidural anesthesia.

PMID: 10710260 - www.pubmed.com

It has not been proven whether one or multiple nerve stimulations and injections provide a higher rate of complete sensory block in both major sciatic nerve sensory distributions below the knee when a popliteal sciatic nerve block is performed using the lateral approach. This prospective, randomized, single-blinded study compared the success rate of the sciatic nerve block using this approach when one or both major components of this nerve (i.e., tibial nerve and common peroneal nerves) are stimulated in 50 patients undergoing foot or ankle surgery. In Group 1 STIM, 24 patients received a single injection of 20 mL of a mixture of 2% lidocaine and 0.5% bupivacaine with 1:200,000 epinephrine after foot inversion had been elicited. In Group 2 STIM (n = 26), 10 mL of the same solution was injected after stimulation of each sciatic nerve component. For patients with complete sensory motor block, there was no difference in onset between groups. However, Group 2 STIM showed a greater success rate compared with the Group 1 STIM (2 STIM: 88% vs 1 STIM :54%; P = 0.007). When two stimulations were used, the onset time of anesthesia in the cutaneous distribution of the common peroneal nerves was shorter than in the tibial nerve (17.5 vs 30 min; P < 0.0001). We conclude that a two-stimulation technique provides a better success rate than a single-injection technique when a popliteal sciatic nerve block is performed using the lateral approach with 20 mL of local anesthetic. IMPLICATIONS: A better success rate is achieved with a double stimulation technique than with a single injection for the sciatic nerve block via the lateral approach at the popliteal fossa when 20 mL of local anesthetics is used.

Publication Types:
Clinical trial
Randomized controlled trial

PMID: 10553838 - www.pubmed.com

Departement d'Anesthesie-Reanimation, Hopital de Bicetre, Le Kremlin-Bicetre, France. darkb@imaginet.fr

We describe a modification of the sciatic nerve (SN) block in the popliteal fossa through the lateral approach. After a brief anatomic study using previously reported landmarks, we propose a new needle orientation associated with a double injection technique after identification of the tibial and the common peroneal nerve. Thirty-four patients undergoing ankle or foot surgery were enrolled in this study. With patients in the supine position, the upper edge of the patella and the groove between the posterior border of the vastus lateralis and the anterior border of the tendon of the biceps femoris were identified. The needle was directed posteriorly with a 20-30 degrees angle relative to the horizontal plane and slightly caudal. Both nerves were individually located with a nerve stimulator and blocked with a mixture of lidocaine-bupivacaine and clonidine. In all but one case, the two nerves were easily located, and no vascular puncture was evident. Effective analgesia was obtained for a minimum of 15 h (first analgesic demand). We conclude that this technique, with a modified direction of the needle and a double stimulation, provides a very high rate of success for SN blockade in the popliteal fossa. Implications: We describe a new lateral approach to the sciatic nerve in the popliteal fossa. The needle was directed caudad and posteriorly while seeking with a nerve stimulator for the tibial and the peroneal nerves, which were blocked separately. This technique was very successful.

Publication Types:
Clinical trial

PMID: 9661550 - www.pubmed.com

BACKGROUND: The main disadvantage of the posterior approach to the block of the sciatic nerve in the popliteal fossa (popliteal block [PB]) is the need to place the patient in the prone position. In this study, the authors examined the clinical utility of a recently described lateral approach to PB that is performed with the patient in the supine position, and they compared its ability to provide reliable surgical anesthesia with that of the posterior approach.

METHODS: Fifty patients undergoing surgery of a lower extremity were randomized to receive the PB using either the lateral (n=25) or the posterior approach (n=25). With both techniques, 40 ml 1.5% alkalinized mepivacaine with 1:200,000 epinephrine were injected on successful nerve localization using low current output nerve stimulation.

RESULTS: There were no differences in American Society of Anesthesiologists physical status or demographic data between the groups (ASA status, I-III; mean age, 5015 yr; 27 men, 23 women). All patients had good intraoperative analgesia, except one in the lateral group, who reported pain outside the distribution of the sciatic nerve.

CONCLUSIONS: Although blockade using the lateral approach took longer to accomplish, both techniques resulted in clinically acceptable anesthesia in the distribution of the sciatic nerve.

Publication Types:
Clinical Trial
Randomized Controlled Trial

PMID: 9637640 - www.pubmed.com