To the Editor:—
I read with great interest the article by Ho et al.1
titled “An Alternative Approach to Ganglion Impar Neurolysis under Computed Tomography Guidance for Recurrent Vulva Cancer.”
As the authors pointed out, there are a variety of approaches for injections of the ganglion impar (ganglion Walther), typically injected in the treatment of coccydynia and various pelvic pain syndromes. The authors described an “alternative” approach to the ganglion impar, initially for local anesthetic block and subsequently followed by neurolysis with 100% alcohol. The authors described using computed tomography guidance while bilaterally inserting 22-gauge, 5-inch spinal needles from both the right and left lateral sacral regions, eventually to meet at the midline just anterior to the sacrococcygeal junction (essentially where the ganglion impar is located).
Compared with a previously described approach of simply passing a smaller, shorter needle through the sacrococcygeal junction, the authors opined that their alternative approach avoided the risks of infection, bleeding, and needle breakage. I respectfully beg to differ.
Although I have personally performed the sacrococcygeal approach to ganglion impar injections for many years and have published on this topic,2,3
I have never heard of a documented case (neither in clinical practice nor reported within the medical literature) where this approach was associated with a substantial risk for any of those three complications, as long as fluoroscopic guidance was used. The sacrococcygeal approach often takes less than 5 or 10 min, and because it is the most direct approach to the ganglion impar, it usually only requires needle penetration of less than 1 inch (compared with 10 inches of total needle length according to the alternative technique described by the authors). Meanwhile, it intuitively seems likely that the authors’ alternative approach is associated with higher (not lower) risks of each of the three items that they paradoxically named as advantages. Specifically, because the risks of infection and bleeding increase with an increased number of procedures (incident dependent risk), using two (bilateral) needle injection sites instead of one would be expected to double the risk of these complications. The name impar
literally means solitary or unpaired; the ganglion impar is duly named because it is a solitary, midline sympathetic nervous system ganglion, unlike all of the other sympathetic ganglia in the body, which are paired (bilateral). Therefore, because image guidance and contrast are used to confirm appropriate placement, even with this “alternative” technique, the use of two (bilateral) needles instead of one seems unnecessarily redundant. Also, with the 10-fold increase in the length of needle inserted by their technique (compared with the sacrococcygeal approach), it seems likely that the authors have substantially increased the likelihood of inadvertent vascular puncture throughout the tract along the way. Other authors have published that longer (not shorter) needles may be associated with needle breakage during ganglion impar injections. In addition, the attempts to control sacrococcygeal placement of such long needle lengths bilaterally, as seen in the article’s computed tomography image, raises serious concerns that less experienced clinicians would be at substantial risk for inadvertently perforating into the peritoneal cavity (rather than staying in the retroperitoneal space, where the ganglion impar is situated), with resultant risks for peritonitis and rectal puncture.
In conclusion, I am of course happy to hear that this individual case worked out well for this particular patient. But I would caution other spinal proceduralists against attempting the alternative approach described by the authors, particularly because the sacrococcygeal approach is much less invasive, intuitively safer, and clinically effective in most cases.
Patrick M. Foye, M.D.
University of Medicine and Dentistry of New Jersey, Newark, New Jersey. email@example.com
1. Ho KY, Nagi PA, Gray L, Huh BK: An alternative approach to ganglion impar neurolysis under computed tomography guidance for recurrent vulva cancer. Anesthesiology 2006; 105:861–2
2. Foye PM, Buttaci CJ, Stitik TP, Yonclas PP: Successful injection for coccyx pain. Am J Phys Med Rehabil 2006; 85:783–4
3. Buttaci CJ, Foye PM, Stitik TP: Coccydynia successfully treated with ganglion impar blocks: A case series. Am J Phys Med Rehabil 2005; 84:218
© 2007 American Society of Anesthesiologists, Inc.