A new perspective on nerve-sparing radical hysterectomy: Nerve topography and over-preservation of the cardinal ligament

Background: Nerve-sparing radical hysterectomy was established by Japanese gynecologists. They identified two parts of the cardinal ligament, namely the vascular part and the neural part, and postulated that the neural part contained the pelvic splanchnic nerves. However, our fresh cadaver studies demonstrated that these nerves ran dorsomedially in contrast to the classical concept. The aim of this study is to further validate this finding in clinical cases. Methods: We examined the intraoperative biopsy specimens collected from the neural part of the cardinal ligament in four patients with cervical carcinoma who underwent nerve-sparing radical hysterectomy with dissection of the neural part. Results: Careful dissections demonstrated that the pelvic splanchnic nerves arise from the dorsomedial side of the neural part at the bottom of the pararectal space. The neural part was composed of a connective tissue with focal positive staining by S-100 protein. Conclusions: We propose that complete dissection of the cardinal ligament should be performed during nerve-sparing hysterectomy to increase its radicality.