Anesth Analg 2007; 105:1519-
© 2007 International Anesthesia Research Society
doi: 10.1213/01.ane.0000286134.19410.40
LETTER TO THE EDITOR
"Gapped Supine" Position for Ultrasound Guided Lateral Popliteal Fossa Block of the Sciatic Nerve
Babak Khabiri, DO,
Fernando Arbona, MD, and
John Norton, DO
Department of Anesthesiology; The Ohio State University Medical Center; Columbus, Ohio; Babak.Khabiri{at}osumc.edu
To the Editor:
Techniques for using ultrasound to assist in blocking the sciatic nerve in the popliteal fossa include placing patients prone or lateral (1). The prone position permits easy imaging of the popliteal region, though it may risk compromise of the airway, especially in sedated patients. In addition, time and effort are required to place patients prone and then supine. Placing patients in the lateral position allows for better access to the airway, with generally less time and effort spent positioning for the block, but it can be more difficult to stabilize the ultrasound probe. Applying pressure to the probe with patients positioned laterally can cause the probe to slide, leading to poor image acquisition. A third method described is to place the patient supine, with the leg to be blocked elevated and supported by a table (2,3). This positioning allows good access to the airway, and does not require the additional time and effort of placing patients prone or lateral. However some disadvantages of this position include: 1) patients may be limited in their ability to flex at the hip; 2) probe placement under the leg may be difficult, as the separation between the leg and the bed may not be adequate; 3) any flexion at the knee may introduce an uneven surface; and 4) the elevated leg may have a tendency to roll. These factors make stabilizing the probe difficult and may inhibit optimal image acquisition.
We believe we have a novel way of positioning our patients supine for ultrasound guided lateral popliteal fossa blocks (Fig. 1). The patient is positioned at the foot of the bed with their mid-thigh at the edge. We then have them lay back and, with the patient supine, we place a small bedside table under their heels and under the calves to support the legs and relieve stress on the knees. This position creates a gap under their knees exposing the popliteal space. The patient is then sedated as deemed necessary. We are able to place the ultrasound probe in this gap, above the popliteal space of the leg to be blocked. The "gapped supine" position allows for a relaxed, stable and even surface for the ultrasound probe. Because the leg is not raised, it is well supported and we avoid placing stress on the lower back. The lack of the bed surface under the knee and probe allows for easy manipulation of the ultrasound probe.
REFERENCES
- Sinha A, Chan VW. Ultrasound imaging for popliteal sciatic nerve block. Reg Anesth Pain Med 2004;29:130–4[ISI][Medline]
- Gray AT, Huzcko EL, Schafhalter-Zoppoth I. Lateral popliteal sciatic nerve block with ultrasound guidance. Reg Anesth Pain Med 2004;29:507–9[ISI][Medline]
- Domingo-Triado V, Selfa S, Sanchez-Contreras D. Ultrasound guidance for lateral midfemoral sciatic nerve block: a prospective, comparative, randomized study. Anesth Analg 2007;104:1270–4[Abstract/Free Full Text]
