Welch Allyn Electrosurgical Unit - User Manual - Manual (Page 10)

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3. TECHNIQUE GUIDANCE
a. When performing the procedure, the endocervix is commonly not included
in the excision, and the results of endocervical curettage are not predictive
of either residual or invasive disease after loop electrosurgical excision pro-
cedure.
b. Loop electrosurgical excision procedures performed with small diameter
wire loop electrodes may produce multiple small pieces of cervical tissue,
and provide a less acceptable tissue specimen for histopathologic analysis.
The influence of electrode design on procedure effectiveness is not com-
pletely understood.
c. Larger lesions involving multiple quadrants of the cervix are more difficult to
remove with either the small or large diameter loop electrodes.
4. SMALL DIAMETER LOOP VS. LARGE DIAMETER LOOP
The histological quality of specimens obtained using small diameter electrodes
is inferior to specimens obtained using large diameter loops due to the increase
contact area between loop and tissue epithelium. While the design of the Welch
Allyn Electrodes wais chosen to optimize specimen quality, operative technique
must take these differences into consideration. Reports of clinical evaluations
of small diameter electrodes describe thermal damage which precluded histo-
logical evaluation of approximately 3% of the tissue specimens. In addition,
since multiple, often irregular, strips of epithelium are excised from the cervix,
it is often difficult for the pathologist to orient the specimens for optimal
histopathological examination.
5. THERMAL EFFECTS ON TISSUE TREATED WITH LOOP ELECTRODES
Thermal effects on tissue specimens may include (i) thermal coagulation injury
of the cervix, up to one-third the thickness of normal epithelium of the cervix,
(ii) fragmentation of squamous epithelium of the cervix attributable to long expo-
sure periods along the excision site that allows heat to dissipate laterally, and (iii)
partial coagulation of the endocervical epithelium because of lateral radiation of
heat. Therefore, the loop electrosurgical excision procedure may produce ther-
mal effects at the periphery of the excised tissue and may make histopatholog-
ic interpretation difficult or impossible and not allow accurate diagnosis and
need for further treatment.
I. PROFESSIONAL USE GUIDE (cont.)
Electrosurgical Unit • Instruction Manual