Anesth Analg 2006;102:1902
© 2006 International Anesthesia Research Society
doi: 10.1213/01.ANE.0000215131.70183.89
LETTER TO THE EDITOR
Patient-Controlled Interscalene Analgesia After Shoulder Surgery: Catheter Insertion by the Posterior Approach
André P. Boezaart, MBChB, FFA(CMSA), MMed(Anaesth), PhD
Department of Anesthesia; University of Iowa; Iowa City, IA; andre-boezaart{at}uiowa.edu
To the Editor:
I would like to correct several misinterpretations of our previous work (1) cited in a recent report by Sandefo et al. (2) on the posterior approach to the brachial plexus.
- In their Figure 1 on page 1497 the authors refer to "Y" as the "Boezaart needle insertion point." On this photograph "Y" is at the level of the angle of the jaw, which does not correspond to the sixth cervical vertebra but rather the fourth; we do, however, use this entry point for deep cervical plexus block for carotid endarterectomy (3). The "X" in Figure 1 would be closer to where we place our needle.
- The authors state that 2.5% of their patients complained of cervical pain, which spontaneously resolved 48 h later at catheter removal. In our early experience with this block (4), 6.25% of the patients complained of cervical pain, and in all these cases the pain resolved after catheter removal. This was not much different from their findings. All our cases were within our first 100 attempts at this approach; with further experience pain ceased being an issue.
- In the discussion section of their report (third paragraph) the authors state that in the technique that we described, the "...needle entry point is located on the lateral side of the neck, which is not very different from the lateral modified approach." This is not correct. In the "longitudinal approach" that we described (5), which was later described as the "lateral approach" (6), the needle entry is just behind the sternocleidomastoid muscle and approximately midway between the clavicle and the mastoid process. In the cervical paravertebral block ("posterior approach") our needle entry is posterior to the levator scapulae muscle and anterior to the trapezius muscle, in the apex of the "V" formed by these two muscles and on the level of the sixth cervical vertebra. This is basically on the "X" in their Figure 1 on page 1497. The only difference is that we separate these two muscles by the fingers of the nonoperative hand. In large patients it would be more than the 3–3.5 cm from the midline that they use, and in smaller patients this would be less. We do not adhere to a fixed distance from the midline but rather to recognizable anatomical structures as surface landmarks.
- The risk of pneumothorax should be very small with either approach. We have a combined experience of more than 4000 catheter placements with this approach and have not encountered a single case of pneumothorax.
- In the same paragraph Sandefo et al. mention that their incidence of cervical pain was infrequent and that contrasts with our experience "...for technical reasons." This does not accurately represent our findings. None of our patients complained of pain at the time of needle or catheter placement. Pain was only evident in the first 48 patients of our pilot study in whom we penetrated the extensor neck muscles, and then only on the day after catheter placement, not at the time of needle or catheter placement. The pain was no longer an issue once we stopped deliberately penetrating these muscles, despite keeping all other aspects of the technique unchanged. We attribute posterior neck pain to the catheter tracking through the often-tender posterior extensor muscles of the neck.
References
- Boezaart AP, Koorn R, Rosenquist RW. Paravertebral approach to the brachial plexus: an anatomical improvement of technique. Reg Anesth Pain Med 2003;28:241–4.[ISI][Medline]
- Sandefo I, Bernard J-M, Elstraete V, et al. Patient-controlled interscalene analgesia after shoulder surgery: catheter insertion by the posterior approach. Anesth Analg 2005;100:1496–8.[Abstract/Free Full Text]
- Boezaart AP, Nosovitch MA. Carotid endarterectomy using single injection posterior cervical paravertebral block. Anesth Analg 2006;102:xxx.
- Boezaart AP, de Beer JF, Nell ML Early experience with continuous cervical paravertebral block using a stimulating catheter. Reg Anesth Pain Med 2003;28:406–13.[ISI][Medline]
- Boezaart AP, de Beer JF, du Toit C, et al. A new technique of continuous interscalene block. Can J Anaesth 1999;46:275–81.[Abstract/Free Full Text]
- Borgeat A, Dullenkopf A, Ekatodramis G, et al. Evaluation of the lateral modified approach for continuous interscalene block for shoulder surgery. Anesthesiology 2003;99:36–2.
