Presacral neurectomy

Presacral neurectomy

Section of the presacral nerve is an effective means of dealing with severe intractable pain localized to the midline when the patient has primary dysmenorrhea which cannot be controlled by other means or when she has increasingly severe menstrual cramps secondary to endometriosis that requires a conservative abdominal operation.

It is the authors’ opinion that the mere removal of a segment of nerve at the bifurcation of the iliac vessels constitutes inadequate resection. The conception of the presacral nerve as a single trunk we regard as erroneous. The nerve bundle has so many ramifying pathways that a complete resection calls for a wide dissection of all the ramifications of the nerve, beginning above the bifurcation of the aorta and extending down along the iliac vessels over the promontory of the sacrum. The field must be kept meticulously dry. Great care must be taken to avoid possible damage to the midsacral veins which empty into the left common iliac vein.

Presacral neurectomy

Conservative operations online: Presacral neurectomy

Figure 1. The abdomen is opened through a paramedian incision and the bowel packed out of the pelvis. The patient is placed in the Trendelenburg position. The sigmoid is retracted to the left. The dotted line indicates the direction and the extent of the proposed incision in the posterior peritoneum.

The surgeon and the assistant elevate the posterior peritoneum from the underlying sacrum as the surgeon divides it with a knife. The incision is then extended down over the promontory and up over the bifurcation of the aorta.

Presacral neurectomy

Figure 2. Silk stay sutures are placed on the divided edges of the peritoneum and clamped long to hang outside the abdominal cavity. This provides a wide open operative field. The surgeon then sweeps the areolar attachments toward the midline from the undersurface of the right peritoneal flap with curved scissors.

Presacral neurectomy

Figure 3. The right ureter comes into view, lying adherent to the under-surface of the peritoneum. It must be identified and left undisturbed.

Figure 4. The dissection should be directed toward the right common iliac artery, and all the ramifying nerve trunks incised, leaving the adven – titia of the vessel clean and glistening. The tissue is mobilized toward the midline as the dissection continues down along the internal iliac (hypogastric) artery. This vessel forms the lateral limits of the dissection.

Presacral neurectomy

Presacral neurectomy

Figure 5. The common iliac artery has been stripped clean of all nerve branches, and the bare, bony surface of the promontory of the sacrum is seen. The left common iliac vein runs almost transversely across the operative field to disappear beneath the right common iliac, where it joins the right common iliac vein to form the inferior vena cava. The nerve is elevated by forceps and gently dissected free of the superior surface of the vein. Small branching veins must be gently isolated, clamped and tied. The entire nerve bundle has been mobilized toward the midline.

Figure 6. While the dissection of the right side proceeds readily with all anatomical structures easily identified, the resection of the nerve on the left can be a bit more complicated because the sigmoid colon must be reflected to expose the nerve.

To facilitate the exposure the left peritoneal flap is placed on traction by the assistant as the surgeon draws the nerve toward the midline and dissects the areolar attachments of the nerve from the undersurface of the left peritoneal flap.

The chief problem is identifying the sigmoidal vessels and distinguishing the main branch of the artery from the left ureter. When isolated and identified, the artery is left on the peritoneum as the dissection proceeds downward.

Figure 7. When the sigmoidal vessels have been identified, further medial traction on the nerve bundle exposes the left ureter. The exposure is materially improved when traction is placed on the peritoneal stay sutures. The dissection then continues as it did on the right side.

Figure 8. With traction maintained on the stay sutures on the peritoneum, the surgeon and assistant draw the bulk of the nerve mass medially as the dissection proceeds along the superior surface of the left internal iliac vein and the left iliac arterial trunks. Note the position of the left midsacral vein as it lies on the promontory of the sacrum prior to joining the left common iliac vein.

Figure 9. The nerve has now been freed of its lateral and inferior attachments to all vessels. It is still continuous with the main body of the trunk above and with the ramifications of the nerve in the lower pelvis. The main body of the nerve is then elevated and Kelly clamps are placed across its substance at about the level where it crosses the left common iliac vein.

The level for the division of the nerve is arbitrarily selected simply to make the dissection easier. Nothing will be gained by trying to resect it at a higher level for the sole purpose of keeping the nerve trunk in continuity. When the clamps have been placed the nerve is divided.

Figure 10. The surgeon then turns his attention to the distal end of the nerve, rotating it toward the symphysis and dissecting the undersurface of the nerve mass from the anterior surface of the sacrum for a distance of about 1 inch. Care must be taken not to damage the midsacral veins which, although no larger than the lead in a pencil, nevertheless may, when traumatized, cause formidable bleeding that is difficult to control. The surgeon will be happy to have dura clips available on the operating table in the event of damage. The best advice is to have the vessels in sight and avoid injuring them.

Presacral neurectomy

Presacral neurectomy

Presacral neurectomy

Presacral neurectomy

Presacral neurectomy

Figure 11. The lateral dissection of the pelvic ramifications of the nerve have carried downward along the hypogastric vessels to the nerve plexus centering around the isthmus of the uterine cervix. Despite the extensive dissection in this area one rarely encounters a patient who has difficulty in emptying her bladder.

The nerve fibers have been freed from the overlying peritoneum in the midline at the level of the cervix. The surgeon then elevates the nerve and under direct vision applies Kelly clamps to the lateral extension of the nerve plexus on both sides. This is necessary since small blood vessels are present and it is of the utmost importance that the operative field be completely dry before the peritoneum is closed. After the clamps have been applied the lower extensions of the nerve are sectioned and removed, and the clamps are left in place.

Presacral neurectomy

Figure 12. Stitch ligatures are then placed to include the tissue in the Kelly clamps. The sutures are tied and divided.

Figure 13. With the lower dissection completed the surgeon now concentrates on the removal of the upper segment of the nerve. Light traction is applied to the clamp previously left on the upper portions of the nerve. The surgeon does this himself for it requires gentle handling since it lies directly over the aorta and vena cava. Holding the clamp in his left hand the surgeon rotates the nerve upward to expose the fine areolar attachments which bind the undersurface of the nerve to the wall of the aorta at its bifurcation. Under direct vision the attachments are gently dissected from the adventitia of the main body of the aorta.

Figure 14. The nerve mass is held up and a Kelly clamp placed across the main body of the nerve above the bifurcation of the artery. The nerve is then divided.

Presacral neurectomy

Presacral neurectomy

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Figure 15. The surgeon then places a stitch ligature around the Kelly clamp and ligates the main nerve trunk.

Figure 16. This drawing shows what the operative field should look like following the extensive dissection which removes all the ramifications of the nerve. Note that both the common and internal iliac artery and vein are stripped clear of any nerve tissue from the bifurcation of the aorta well down over the promontory and bony surface of the sacrum. Note also that the midsacral vein and its tributaries are intact and that the wound is dry.

Figure 17. To have a satisfactory dissection the operative field should be bloodless. Before the peritoneal incision is closed all bleeding points must be controlled. A running atraumatic catgut suture may be used for closure.

Presacral neurectomy

Presacral neurectomy

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