Loop Electrosurgical Excisional Procedure (LEEP) History and
Principles
AAFP Advanced Colposcopy Course - 1994
E.J. Mayeaux, Jr., M.D.
Assistant Professor of Family Medicine
Clinical Assistant Professor of Obstetrics and Gynecology
Louisiana State University Medical Center Shreveport, Louisiana
Introduction
I. Introduction
A. The prevalence of premalignant cervical lesions is increasing in the United States. 1
B. Usually occur in women of childbearing years who may not have completed their families. 1-5
C. Some traditional choices for treatment include cryosurgery, electrocoagulation, and laser vaporization.
1. Outpatient procedures - allow for future pregnancies.
2. Ablative therapies - no tissue is sent for pathological inspection.
3. Raises the possibility of missing microinvasive or invasive cancer.
D. Additional choices for treatment include laser or knife conization and hysterectomy.
1. Produce tissue specimens with wide margins.
2. May require hospitalization with general anesthesia
3. Hysterectomy precludes future pregnancies.
4. Requires considerable skill.
D. Recently, low voltage, high frequency, thin wire loop electrodes have been used to remove cervical lesions.
E. Loop Electrosurgical Excisional Procedure (LEEP) allows for the outpatient treatment of cervical lesions with good pathology specimens and low risk of affecting childbearing ability. 6
II. History
A. Hot cautery has been used since the begining of recorded history.
B. Electrocautery (using an electric probe to cause a therapeutic burn) came into use in the 18th and 19th centuries.
1. In 1906 Hunner reported electrocauterization to prevent cervical cancer.
2. Later large scale studies demonstrated that prophylactic electrocautery prevented cervical cancer.
3. Basically used "soldering irons" to produce this electrocautery.
C. Hyams, in 1928, developed an electrode to do a "hot wire cone biopsy."
1. Produced major thermal artifact.
2. Had significant late bleed and cervical stenosis problems.
D. Physicians have experimented with high frequency current for treatment of cervical dysplasia since the 1940s. Young used fulguration at this time with good results.
E. In the mid 1960s in France, Cartier started using small thin wire loops for SIL biopsies and excisions. 8,9
1. Small loops (5 by 5 mm) required multiple passes
2. Damaged the tissue specimens.
F. Prendiville experimented with larger loops with insulated cross-bars and published a paper on "Large Loop Excision of the Transformation Zone" or LLETZ in 1989. 4
G. LEEP has historically been called Diathermy Loop Treatment, Loop Excision of the Transformation Zone (LETZ), and Large Loop Excision of the Transformation Zone (LLETZ), and these terms can still be found in the literature.
H. Although several names are still in use, Loop Electrosurgical Excisional Procedure (LEEP) is becoming the preferred term in the United States.
III. Physics
A. LEEP makes use of low voltage and relatively high frequency electric current. The frequency is too high to produce nerve stimulation or muscle contractions.
B. As the loop is introduced to the tissue in cutting mode, an arc occurs near the point of contact causing the cells to be rapidly heated and explode into steam. A steam envelope forms that keeps the tissue and electrode apart which allows for continued arcing and thus cutting.
1. A slow moving, clean electrode produces the best cut.
2. When the probe is moved too fast or the current is stopped, the probe contacts the tissue and thermal damage results. "Never stop in the middle of a LEEP cut."
C. The current is quickly dispersed through the patient's body to the grounding electrode without further tissue damage.
1. This is a monopolar output where cutting or fulgeration occurs at one electrode and the current is dispersed through a return (or neutral) electrode.
2. Bipolar outputs use 2 active electrodes (such as the arms of a pair of forceps) and the circuit is completed between them - not used in LEEP. See graphic.
3. The return electrode may be an electrolyte gel pad or an antenna in higher frequency units.
4. The large surface area of the return electrode prevents high charge density and thus prevents burns. An improperly applied return electrode can cause burns.
D. In the coagulation mode, fulguration of tissue is produced with short bursts of high peak voltage current.
1. This mode is often used with a ball electrode to achieve hemostasis.
2. The larger surface area of the ball allows more random sparking that causes more thermal damage and thus coagulation and hemostasis.
IV. Materials
A. Electrosurgical generators used for LEEP are identical to ones used in laparoscopic and urological surgery. Electrical generator features include:
1. Isolated circuitry - the generator senses when part of the electrical current is not returning through the ground pad and cuts the current off. Helps prevent "alternate site burns."
2. Ground referenced - older type - does not contain isolated circuitry.
3. Return electrode alarm - warns operator if the return electrode is not plugged in or is inoperative.
B. Alternating current output ranges between 100 and 4000 KHz.
1. At frequencies of greater than 100 KHz, cellular membrane depolarization does not occur, so there is no associated shock or muscular contraction.
2. Pure cutting current is a continous sine wave current that produces sharp cuts with little thermal damage or hemostasis.
3. Pure coagulation current causes significant thermal damage and hemostasis.
4. Blend mode mix the 2 types of current in varying degrees to produce cuts with variable hemostasis.
C. The relative cutting power is proportional to the amount of current which is usually measured in watts or as an ordinal scale.
1. As the surface area of the cut increases, the amount of power needed to make the cut also increases.
2. ie Larger or deeper cuts require higher current settings.
3. Drier or more keratinized skin requires higher current settings.
4. Setting the current too high results in increased thermal damage and increased risk of unintentional burns.
D. Most loops have an insulated shaft and crossbar to prevent accidental thermal injury. Common loop sizes range from 1 by 1 cm to 2.0 by 1.5 cm.7
1. The stainless steel or tungsten wire of the loop is approximately 0.2 mm thick.
2. Ball electrodes ranging from 3mm-5mm are used for fulguration.
E. Smoke evacuators consisting of suction devices with filters are used to eliminate the steam or smoke generated during the procedure. 7
1. Often it is a separate unit but some LEEP units now have them built in.
F. A plastic or coated speculum is recommended because contact with a metal speculum will cause discomfort (but usually no burn because of the large surface area).
1. The tube on a smoke evacuator speculum removes the smoke from deep in the vagina and pulls air into the vagina. This causes fewer odor problems in the treatment room.
G. Coated side wall retractors and lidocaine injectors may also be useful.
IV. Implications for Family Practice
A. With the low cost of equipment and the ease of mastery, LEEP should be an excellent procedure for the practicing family physician.
B. Basic technique can be taught in a conference setting in one day, and this training could be incorporated into existing colposcopy workshops for family physicians.
C. With a relatively low cost for a state-of-the-art LEEP unit, it is cost effective for even infrequent use. It can be used for removal of both cervical and skin lesions.
D. It is also possible that widespread use of LEEP will result in a higher standard of care for patients.
E. It can allow for fewer visits to work up and treat cervical lesions, and lowers the danger of loss of patient follow-up.10
F. The risk of missing microinvasive disease and incomplete excision of lesions can also be decreased.
G. LEEP conization requires little additional training, is safe, and allows for outpatient treatment of patients with inadequate colposcopies.
H. Patients can also benefit from being able to get their care from their own family practitioner. Continuity of care can thus be increased for these patients and costs controlled.
I. The AAFP and ACOG have not as yet taken a stand on the use of LEEP in clinical practice.
1. This could potentially change the patterns of LEEP usage in the future.
J. Studies indicate LEEP is 90 to 98 percent effective in treating SILs. 2-4,11,12 This compares to 81 to 95 percent for cryosurgery 13-19 and 91 to 94 percent for laser. 8,20
1. LEEP is also well tolerated, with 85 percent of patients reporting no discomfort.
2. Most patients who do report discomfort indicate the degree of pain is mild. 3,8
V. Conclusion
A. LEEP is a new diagnostic and therapeutic modality for the treatment of SILs.
B. The low cost of set up and ease of use lends itself well to use by family practitioners.
C. Patient acceptance of the procedure is high, and cure rates and complication rates are comparable to similar treatment methods.
D. Widespread use of LEEP by family physicians can be expected in the future.
References:
1. Sadeghi SB, Sadeghi A, Stanley JR. Prevalence of dysplasia and cancer of the cervix in a nationwide, planned parenthood population. Cancer 1988; 61:2359 - 61.
2. Chappatte OA, Byrne DL, Raju KS, Nayagam M, Kenney A. Histological differences between colposcopy-directed biopsy and loop excision of the transformation zone (LETZ): A cause for concern. Gyn Ocol 1991; 43:46-50.
3. Luesley DM, Cullimore PC, Redman CW, et al. Loop diathermy excision of the cervical transformation zone in patients with abnormal smears. Br Med J II 1990; 300:1690-93.
4. Prendiville W, Cullimore J, Norman S. Large loop excision of the transformation zone (LLETZ). A new method of management for women with cervical intraepithelial neoplasm. Br J Obstet Gynaecol 1989; 96:1054-60.
5. McIndoe GAJ, Robson MS, Tidy JA, Mason WP, Anderson MC. Laser excision rather than of vaporization: The treatment of choice for cervical intraepithelial neoplasia. Obstet Gynaecol 1989; 74:165-68.
6. Bigrigg MA, Codling BW, Pearson P, Read MD, Swingler GR. Pregnancy after cervical loop diathermy. (letter) Lancet 1991; 337:119.
7. Mayeaux EJ, Harper MB. Loop Elecrtosurgical Excisional Procedure. J Fam Pract 1993; 36:214-19.
8. Gunasekera PC, Phipps JH, Lewis BV. Large loop excision of the transformation zone (LLETZ) compared to carbon dioxide laser in the treatment of CIN: A superior mode of treatment. Br J Obstet Gynaecol 1990; 97:995-8.
9. McLucas B, Emens M, Hamou J, Rothenburg R. Diathermy loop treatment of CIN. Interpersonal perspectives. The Female Patient 1990; 15:79-89.
10. Bigrigg MA, Codling BW, Pearson P, Read MD, Swingler GR. Colposcopic diagnosis and treatment of cervical dysplasia at a single clinic visit. Experience of low-voltage diathermy loop in 1000 patients. Lancet 1990; 336:229-31.
11. Wright TC, Gagnon S, Richart RM, Ferenczy A. Treatment of cervical intraepithelial neoplasia using the loop electrosurgical excisional procedure. Obstet Gynecol 1992; 79:173-8.
12. Creasman WT. Cryosurgery: Symposium on cervical neoplasia. Colposcopy Gynecol Laser Surg 1985; 1:276-81.
13. Draeby-Kristiansen J, Garsaae M, Bruun M, Hansen K. Ten years after cryosurgical treatment of cervical intraepithelial neoplasia. Am J Obstet Gynecol 1991; 165:43-5.
14. Young C, Malvern J, Chamberlain G. Out-patient cervical cryosurgery. J Obstet Gynaecol Br CommonW 1972;79:753-5.
15. Crisp WE. Cryosurgical treatment of neoplasia of the uterine cervix. Obstet Gynecol 1972; 39:495-9.
16. Kaufman RH, Strama T, Norton PK, Conner JS. Cryosurgical treatment of cervical intraepithelial neoplasia. Obstet Gynecol 1973; 42:881-6.
17. Kaufman RH, Conner JS. Cryosurgical treatment of cervical dysplasia. Am J Obstet Gynecol 1971; 109:1167-74.
18. Tredway DR, Townsend DE, Hovland DN, Upton RT. Colposcopy and cryosurgery in cervical intraepithelial neoplasia. Am J Obstet Gynecol 1972; 114:1020-4.
19. Baggish MS. A comparison between laser excisional conization and laser vaporization for the treatment of cervical intraepithelial neoplasia. Am J Obstet Gynecol 1986; 155:39.
20. Randall T. Loop Electrosurgical Excisional Procedures gaining acceptance for cervical intraepithelial neoplasm. JAMA 1991; 266:460-62.
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