Atlas of Colposcopy: Principles and Practice

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Treatment by cryotherapy – Steps  

  • Counsel the woman, and obtain informed consent.
  • Colposcopically re-evaluate the lesion and ensure that:
    • The lesion is completely ectocervical, with a type 1 TZ.
    • The lesion does not extend to more than 75% of the cervix.
    • The lesion can be fully covered by the largest cryotip.
    • The lesion does not have any features suspicious of cancer.

  • Remove the colposcope, and use a focusing light for the procedure.
  • No anaesthesia is required for cryotherapy.
  • Select a probe with a tip of the appropriate diameter that will cover the lesion completely. Attach the probe to the handle grip (cryogun).
  • Connect the valve with the pressure gauge to the gas cylinder. The pressure of the gas cylinder should be 40–70 kg/cm2 when the gas is flowing (indicator in the green zone).
  • Wipe the cryotip with saline or lubricant, to ensure adequate thermal contact.
  • Apply the probe tip firmly to the cervix with the centre of the tip on the external os.
  • Check that the vaginal walls are not touching the probe tip.
  • Press the trigger on the handgrip so that gas starts flowing, and start the timer.
  • Check for the formation of ice at the tip of the probe.

  • Release the trigger after 3 minutes, when you will see an ice ball formed over the cervix extending 4–5 mm beyond the edge of the tip.
  • If the ice ball has formed adequately, the probe tip will remain stuck to the cervix.

  • Wait for 5 minutes for thawing, when the ice will melt and the probe may detach from the cervix.
  • Reapply the probe at the same place as before, and freeze the cervix for another 3 minutes.
  • Release the trigger and wait until the ice melts and the probe detaches from the cervix on its own.
  • The cervix will have a white crater, which indicates that the cervix is properly frozen.

  • Remove the speculum gently.
  • Ask the woman to continue lying down for 5 minutes before letting her getting up.
  • Counsel the woman, and give appropriate follow-up advice.
For additional information, please refer to WHO technical specifications: cryosurgical equipment for the treatment of precancerous cervical lesions and prevention of cervical cancer.

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