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From the *Department of Anesthesiology and Section of Pain Management, Emory University School of Medicine, Atlanta, Georgia.
Address correspondence and reprint requests to Michael G. Byas-Smith, MD, Department of Anesthesiology, Emory University School of Medicine, 1364 Clifton Rd., Atlanta, GA 30322. Address e-mail to Michael.Byas-Smith{at}emory.org.
Abstract
Ultrasound technology has advanced regional anesthesia and pain management, by improving accuracy and reducing complication rates. We have successfully performed cryoablation of intercostal nerves with ultrasound guidance with no complications. Four patients with postthoracotomy pain syndrome had pain relief for at least 1 mo after selective cryoablation of intercostal nerves at the mid-axillary line. Visualizing the pleura during the procedure is the greatest benefit of using ultrasonography, especially in thin patients whose intercostal groove to pleural distance may be <0.5 cm. Although further studies are needed, we feel that this new technique should reduce the risk of pneumothorax as well as improve the success of cryoablation.
Cryotherapy techniques are used to provide long-term analgesia. Lloyd et al. (1) described the first use of cryoanalgesia for intractable pain. Since their report, cryoanalgesia has been studied most extensively for treatment of postthoracotomy neuralgia (2–9). Cryotherapy can provide profound analgesia and with few complications (10,11).
Current neurolysis methods for postthoracotomy pain use bony and soft tissue landmarks to place the needle near the intercostal nerve (12) Unfortunately, these types of "blind" techniques unavoidably carry a significant risk of complications. Rates for a resulting pneumothorax from cryoablation have been reported to be as frequent as 7% (11).
CASE REPORT
A 50-yr-old male with esophageal carcinoma, otherwise healthy, was referred for further treatment for postthoracotomy pain after gastroesophagectomy. One month after surgery, the patient began complaining of sharp, continuous, incisional pain, worse with deep inhalation, radiating from his right side to the middle of his anterior torso around his lower ribs. He received some relief from a number of medical treatments. On two separate occasions, diagnostic intercostal nerve blocks at ribs 9, 10, and 11 with a long-acting local anesthetic provided complete pain relief for many hours. As the pain became increasingly intolerable, cryoablation of his intercostal nerves was recommended.
METHODS
After informed consent was obtained the patient was taken to the operating room and positioned in the left lateral decubitus position and draped in a sterile manner, with his right fifth through twelfth ribs exposed in the surgical field.
A portable ultrasound machine and probe (Sonosite® MicromaxxTM with the HFL38/13–6 MHz transducer) was used to mark the superior and inferior borders of ribs 5 through 12 and confirmed with computed tomography fluoroscopy.
The optimal entry point for each nerve lesion was at the superior border of the rib inferior to the nerve to be blocked. Thus, when the intercostal nerve underneath the ninth rib was ablated, the entry point of the probe was the superior border of the tenth rib. The approach points were 1–2 cm posterior to the mid-axillary line. The skin was then infiltrated with 1 mL of 1% lidocaine, and under the rib of the nerve to be ablated, 2 mL of 1% lidocaine was injected. Next, a cryoanalgesia probe (Coopersurgical 17-gauge Trocar 2.5 mm x 1.5 mm tip with 100 mm shaft) was inserted using ultrasound guidance under the ninth, tenth, and eleventh ribs (Fig. 1). Proper position was confirmed with visualization under ultrasound and a distinct loss of resistance when piercing through the internal intercostal muscle.
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Cryoablation, with N2O, was initiated at –50°C for 60 s, with a second lesion for 30 s. This procedure was continued for nerves below the ninth, tenth, and eleventh ribs. The patient tolerated the procedure well. His pain symptoms resolved within 1 h postoperatively and were still absent at his 2-mo follow-up. There were no complications for this procedure.
DISCUSSION
The obvious advantage of performing intercostal cryoneurolysis is the likely reduction in pneumothorax. Under ultrasound, we can clearly see the pleura, monitor the patient during inhalation, and determine the safest approach for advancing the probe (Fig. 2). Once the procedure is complete, the patient may be monitored with the ultrasound device for any acute development of a traumatic pneumothorax, eliminating the need for radiographic evidence (i.e., supine chest radiograph) of an intact pleural space (14,15).
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It is important to recognize that the intercostal nerve cannot be visualized under ultrasonography because of its anatomic placement behind the intercostal groove. Investigators rely on placing the cryoprobe tip just beneath the intercostal groove and using the ice ball which forms around the visible needle to verify correct placement. Conclusive evidence of improved outcomes using ultrasound-guided techniques will require a prospective, randomized, controlled trial (16,17).
Footnotes
Accepted for publication June 23, 2006.
Supported by the Emory University Department of Anesthesiology.
REFERENCES
This article has been cited by other articles:
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  E. H. Williams, C. G. Williams, G. D. Rosson, R. F. Heitmiller, and A. L. Dellon Neurectomy for treatment of intercostal neuralgia. Ann. Thorac. Surg., May 1, 2008; 85(5): 1766 - 1770. [Abstract] [Full Text] [PDF]
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