Coaxial Imaging Technique for Superior Hypogastric Plexus Block:

The Optimal Approach for a Superior Hypogastric Plexus Block

INTRODUCTION

Superior hypogastric plexus block (SHGPB) is technically difficult, and an accurate procedure is required to avoid potential complications. We attempted to determine the reference angles for fluoroscopy-assisted SHGPB and to establish a predictor as a guide to select the optimal approach between the classic posterior approach and transdiscal approach.

METHODS

Abdominopelvic computed tomography (CT) scans from 268 patients diagnosed with pelvic malignancies were examined. The oblique and axial angles needed for the fluoroscope were measured both for posterior and transdiscal approaches by simulating the needle trajectory on CT imaging. We developed an SHGPB index defined by the ratio (%) of the interposterior iliac border distance to the L5 body transverse diameter, which represents the relative transverse diameter of the bony pelvis. We evaluated whether it can help select the optimal approach for the SHGPB between the posterior and transdiscal approaches.

RESULTS

Males had a significantly smaller angle than females (right oblique angle for posterior approach, males 14 [range 12 to 17] degrees vs. females 19 [range 16 to 23] degrees; P < 0.001). An SHGPB index of < 150 was an independent predictor for failure of the classic posterior approach (odds ratio 31.3, 95% confidence interval 5.1 to 104.7).

CONCLUSIONS

The optimal right oblique angle of fluoroscopy for the posterior approach is 13° to 15° in males and 19° to 20° in females. The transdiscal approach may be favored over the posterior approach when the bony pelvis is narrow relative to the target vertebral body, which can be measured by the SHGPB index being < 150.

The role of image guidance in improving the safety of pain treatment

The use of fluoroscopy, computed tomography, and, most recently, ultrasound in the pain clinic all have advanced rapidly, yet there is scant evidence that this improves the safety or efficacy of pain treatment. In this manuscript, the available evidence about the usefulness of diagnostic imaging and image guidance in planning and delivering pain treatment is critically reviewed. The use of image guidance has become a routine and integral component of pain treatment; however, there is insufficient scientific evidence to judge whether this has improved safety. The logical appeal is overwhelming, to the point that it is now unlikely that scientific comparisons of most techniques with and without radiographic guidance will ever be conducted. This analysis can serve to guide future investigators who set out to understand how to apply new imaging techniques, and in the process, how to rigorously evaluate their usefulness.

The developmental anatomy of the human superior hypogastric plexus: A morphometrical investigation with clinical and surgical correlations

The superior hypogastric plexus (SHP) is the part of the autonomic nervous system, which is responsible for the sympathetic innervation of pelvic organs and extrapelvic genitals in humans of both sexes. The SHP also functions as the anatomic pathway for the major part of visceral sensitive fibers originating from pelvic viscera. In this study, the morphology of the SHP was analyzed through anatomical dissections performed both in human adult and fetal cadavers. A computerized morphometrical investigation of the SHP was also performed and the resulting quantitative data statistically assessed. The comparison between fetal and adult SHP revealed that in the male group there was a developmental increase of six times (in height) and of about five times (in width); while in the female group, there was a developmental increase of 3.5 times both in height and width values. In addition, the distance from the superior border of the SHP to the bifurcation of the common iliac arteries presented a developmental increase of about six times in the male group, and about four times in the female group. We propose an original morphological classification with six types, based upon the anatomical arrangement of the nervous fibers in this autonomic plexus.