Real-Time Three-Dimensional Ultrasound forContinuous Popliteal Blockade: A Case Reportand Image Description

Neil G. Feinglass, MD*

Steven R. Clendenen, MD*

Klaus D. Torp, MD*

R. Doris Wang, MD*

Ramon Castello, MD†

Roy A. Greengrass, MD*

Two-dimensional ultrasound guidance has been used as an adjunct for neuralblockade. With the development of newer ultrasound technology, three-dimensionalultrasound imaging is now available and may offer improved visualization of anatomicstructures and relationships. We describe the successful blockade of the popliteal nervewith three-dimensional ultrasound guidance and image description.(Anesth Analg 2007;105:272–4)

Two-dimensional (2D) ultrasound is commonly usedfor guiding access to vascular structures, in transesoph-ageal echocardiography, and most recently to guideperipheral nerve blocks (1–4). Several studies haveshown the utility of 2D ultrasound to define the anatomyand to guide needle insertion (5). Peripheral nerves,being encased in fat, have ideal acoustic properties.Neighboring vascular structures often allow Dopplerimaging (color, pulsed-wave, and continuous-wave) toprovide additional structural detail and avoid vascularpuncture and damage.

Nevertheless, 2D ultrasound has limited ability tovisualize spatial relationships (3,5). This resultsfrom the nonlinear courses taken by vascular andneural structures as they traverse tissue planes (5).The 80-degree, cross-sectional, ultrasound beam canidentify cross-sections of these structures only asthey traverse the beam. However, visualizing theend of a structure, such as the needle tip, is oftendifficult.

Three-dimensional (3D) ultrasound can image theentire anatomical region, nerve thickness, and 3Drelationships. Anesthetic distribution can be visual-ized in all 360-degree planes. This is generated fromsimultaneous reconstruction of two standard orthogo-nal 2D planes (X and Y axes), with the additionaldimension of elevation (Z axis). The image may bedigitally rotated 360 degrees for better visualization ofthe anatomic structures at the time of study, or at alater date for postblock analysis.

This report describes the first real-time application of3D ultrasound reconstruction for guidance of the inser-tion of a popliteal nerve catheter for ankle surgery. Thisultrasound technology is commercially available and iscurrently used in cardiac ultrasonography.

CASE REPORTThe criteria for publication and patient care were met by

the Mayo Investigational Review Board. The patient was a73-year-old woman scheduled for major reconstructive footsurgery. Informed consent was obtained from the patient fora continuous popliteal nerve catheter. The nerve block wasperformed in the preoperative patient holding area. Afterapplication of standard ASA monitors and administration ofnasal oxygen, the patient was sedated with 1 mg midazolamand 50 �g of fentanyl IV. The block was performed with thepatient in the prone position. A pillow was placed under theleg to allow for slight knee flexion. 3D ultrasound (3DUltrasound System IE-33 with � 3-1 Matrix Array Probe,Philips Medical Systems; Andover, MA) was used duringthe procedure for needle guidance, confirmation of thecatheter placement, and imaging of local anestheticdistribution.

The knee flexor crease was identified and marked. Theborders of the biceps femoris and semitendinosus muscles

This article has supplementary material on the Web site:www.anesthesia-analgesia.org.

From the Departments of *Anesthesiology, and †CardiovascularDisease, Mayo Clinic, Jacksonville, Florida.

Address correspondence and reprint requests to Neil G.Feinglass, MD, Mayo Clinic, Jacksonville, FL. Address e-mail tongf06@bellsouth.net.

Copyright © 2007 International Anesthesia Research SocietyDOI: 10.1213/01.ane.0000265439.02497.a7

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were marked 8 cm above the knee crease. A line was drawnbetween the two muscles. The midline point of this line was thepoint of needle insertion. 3D ultrasound scanning confirmedthe presence of the popliteal nerve at a depth of 3 cm from theskin at the surface mark. The 17-gauge, 50-mm Arrow® con-tinuous peripheral block needle was directed cephalad towardthe nerve at an 80 degree angle to the skin under continuousultrasound guidance of the needle. As the needle approachedthe nerve, 2 Hz electrical stimulation was initiated at 1.5 mA.Ultrasound was used to guide the needle to the popliteal sciaticnerve. After obtaining toe flexion at 0.5 mA, a 19-gaugestimulating catheter (Stimucath®, Arrow International, Read-ing, PA) with an embedded wire to enhance echogenicity wasinserted 5 cm past the tip of the needle with electrical stimu-lation guidance. The 3D ultrasound demonstrated the catheterto be in close proximity to the nerve (Fig. 1a).

Under 3D ultrasound visualization, the initial injection oflocal anesthetic (3 mL followed by 7 mL of 0.5% ropivacaine)was observed to lie posterior to the nerve (Fig. 1b). Continu-ous injection of local anesthetic revealed complete encircle-

ment of the nerve (Fig. 1c). Subsequent clinical examinationrevealed anesthesia in the sciatic distribution of the leg. Asaphenous nerve block at the knee was added to completethe leg anesthesia. The patient was taken to the operatingroom and underwent uneventful surgery.

DISCUSSION3D ultrasound images are a significant advance in

digital ultrasound image processing. This technologyhas allowed the cardiac sonographers to better definevalvular pathology as well as the size and function ofcardiac chambers with improved definition of detail (6).3D image reconstruction that required 20 min in the pastcan now be completed in real-time as demonstrated inthis case report.

The 3D ultrasound transducer used for our patientwas the first generation device that was designed for

Figure 1. a, Popliteal fossa imaged with 3D ultrasound from the posterior to anterior approach. Arrows identify the poplitealcatheter (after needle removal) in long axis coursing towards the sciatic nerve seen in short axis. Figures 1b and 1c aredeveloped upon rotating the image using the electronic processor-derived rotation of the image in real time. b, Popliteal fossaimaged with 3D ultrasound from the posterior aspect of the knee as in Figure 1a. This image has now been electronicallyrotated to allow for visualization of the sciatic nerve in long axis. The nerve is seen in its entire thickness. The peripheral nervecatheter is seen partially transected as it courses to the popliteal nerve. The catheter has been injected with 10 mL of localanesthetic. c, Transducer location has remained as in Figures 1a and 1b. The image is rotated again to a new vantage pointelectronically with 3D reconstruction. In this orientation, the catheter is seen fully in short axis with anesthetic deposition seensurrounding the catheter. Below the catheter, the popliteal nerve bundle is also seen in short axis with further deposition ofanesthetic seen below the nerve. Twenty mL of local anesthetic has been deposited.

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deep penetration of tissues and 3D cardiac reconstruc-tion using frequencies of 1–3 MHz range. Secondgeneration 3D transducers use frequencies of 2–7MHz, which are better suited for common neuralstructures. Commercial vendors are customizing thesesystems for regional anesthesia blockade. The ease ofuse of these systems and improved image quality willfollow rapidly. It should also be appreciated thatwhile imaging in 3D, the clinician can at any timerapidly revert to standard 2D images. Although theapplication of 2D ultrasound to peripheral neuralblockade is well established, we believe 3D applica-tion will further enhance the use of ultrasound inconjunction with regional anesthetic techniques.

REFERENCES

1. Eichenberger U, Greher M, Kapral S, Marhofer P, Wiest R,Remonda L, Bogduk N, Curatolo M. Sonographic visualizationand ultrasound-guided block of the third cccipital nerve. Anes-thesiology 2006;104:303–8.

2. Sandu NS, Capan LM. Ultrasound-guided infraclavicular bra-chial plexus block. Br J Anaesth 2002;89:254–9.

3. Chan VW, Nova H, Abbas S, McCartney CJ, Perlas A, Xu DQ.Ultrasound examination and localization of the sciatic nerve.Anesthesiology 2006;104:309–14.

4. Gray AT. Ultrasound-guided regional anesthesia. Current stateof the art. Anesthesiology 2006;104:368–73.

5. Jan van Geffen G, Gielen M. Ultrasound-guided subglutealsciatic nerve blocks with stimulating catheters in children: adescriptive study. Anesth Analg 2006;10:328–33.

6. Valocik G, Kamp O, Visser CA. Three-dimensional echocardiog-raphy in mitral valve disease. Eur J Echocardiogr 2005;6:443–54.

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