Immunohistochemical Analysis of the Cervix: Surgical Simulation of Electrocautery to Treat Cervical Dysplasia

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Abstract Body : Introduction: Loop electrosurgical excision procedure (LEEP) is considered one of the gold standard methods for treating cervical dysplasia (CD) and is performed on hundreds of thousands of women annually. This electrocautery method has several benefits, including the excision of harmful pre-cancerous tissues. However, the effects of thermal artifact after LEEP have been noted, including inflammation, localized ischemia, and morphologic cellular changes. Given these known risks of local tissue changes, it is imperative to investigate how the electrocautery from LEEP may affect the cervix. Further, the potential for a damaging association of cautery artifact with cervical structures such as glands, nerves, and blood vessels, should be evaluated. The potential removal of, or damage to, these innervated structures should be investigated to provide a basis for studies aimed at elucidating post-LEEP alterations of cervix function.

Objectives: To characterize innervated structures in cervical tissue using immunohistochemistry (IHC), and to assess the qualities of excised tissue during LEEP using cadaveric simulation.

Methods: Seven samples from archival hysterectomy tissue were used to characterize the cervix. One cervix was excised following careful dissection from a fresh cadaver. Following dissection, the fresh cervix underwent surgical simulation of LEEP by a board-certified gynaecologist. All samples (n=8) were paraffin embedded, sectioned at 5 𝜇m, and stained with hematoxylin and eosin. IHC was performed to characterize general (PGP9.5), autonomic (TH, VIP), and sensory (CGRP) innervation.

Results: IHC of the cervix using neuronal marker PGP9.5 showed distribution of innervated glands, blood vessels, and putative nerve bundles throughout cervical stroma. Immunoreactivity for autonomic (TH, VIP) and sensory (CGRP) markers was found in blood vessels and nerves within the transformation zone, and at the reported depth of conservative LEEP (< 2 mm). Innervated cervical glands were also found proximal to the transformation zone, specifically near the squamocolumnar junction. Cadaveric simulation of LEEP revealed blood vessels and nerves present in the excised tissue specimen, and in close proximity (< 250 𝜇m) to the surgical margin. Fulguration artifact was visible along the surgical margin of the excised specimen and of the remaining cervix. Histological artifact and potential antigen signal loss were reported in surgical simulation samples. The IHC characterization of cervix tissue in combination with the cadaveric surgical simulation reveals the potential for innervation loss or damage from LEEP.

Conclusions: The present study characterized cervix innervation using IHC, and identified sensory, sympathetic, and parasympathetic innervation in relation to the surgical field of LEEP. Using a cadaveric surgical simulation, we showed that innervated cervix microstructure may be removed during LEEP, and that thermal artifact to remaining cervical tissue may be associated with possible nerve injury. Future studies should investigate the mechanistic link between effects of electrocautery on cervix innervation, and reported patient symptoms relating to pregnancy, sexual, and psychological issues. Given the presented evidence, gynaecologists should be aware of these possibilities, and counsel their patients accordingly to make informed and autonomous decisions.