Figure 15.6 Fibroid classification. (From Munro MG, Critchley HO, Broder MS, et al. FIGO Working Group on Menstrual Disorders. FIGO classification system (PALM-COEIN) for causes of abnormal uterine bleeding in nongravid women of reproductive age. Int J Gynaecol Obstet 2011;113:3–13)
Hysteroscopic resection of a submucous fibroid can be accomplished under visual control using a telescope and continuous ﬂow of distension ﬂuid through the uterine cavity. The electrosurgical working element uses monopolar or bipolar electrodes. Monopolar electrodes require nonconducting distending solution (sorbitol 5%, sorbitol 3% with mannitol 0.5%, or glycine 1.5%), while bipolar electrodes can be used with saline.
Cervical dilation is usually required prior to insertion of the hysteroscope. Cytotec may facilitate easier dilation (142). The cutting loop is passed beyond the fibroid and cutting activated only when the loop is moving toward the surgeon and in direct view. Fibroids should be resected down to the level of the surrounding myometrium and, if fertility is desired, care should be taken to avoid excessive thermal damage to normal myometrium. Often, the remaining portion of the fibroid will be expressed into the uterine cavity by uterine contractions, allowing further resection. Fragments of fibroid are removed from the cavity with a grasping forceps or by capturing the fragments with the loop and extracting the telescope. G0 and G1 fibroids up to about 5 cm may be resected hysteroscopically.
G2 fibroids require careful preoperative evaluation with saline-infusion sonography or MRI to gauge the thickness of normal myometrium between the fibroid and the serosa in order to assess the potential risk of uterine perforation with the loop electrode. The risk of perforation increases with deeper myometrial involvement of the fibroid (143). In some cases, repeat resection may be required after a few weeks, as the remaining portion of the fibroid is expressed into the uterine cavity by uterine contractions.
Procedure-Specific Risks Cervical dilatation or insertion of the hysteroscope can cause uterine perforation, as can deep myometrial resection. Often the first sign of perforation is a rapid increase in the ﬂuid deficit. Careful inspection of the uterine cavity should be undertaken to look for brisk bleeding or bowel injury. If no injury is apparent, the procedure should be terminated and the patient should be
Endometrial Ablation for Abnormal Bleeding Associated with Fibroids observed and may be discharged if stable (144). If a perforation occurs during activation of the electrode, then laparoscopy should be performed to carefully inspect for bowel or bladder injury.
Intravascular absorption of distending media is a potentially dangerous complication that can result in pulmonary edema, hyponatremia, heart failure, cerebral edema, and even death (145). Careful monitoring of the ﬂuid deficit is important and a ﬂuid deficit of 750 mL during surgery should serve as a warning sign, with planned termination of the procedure.
Many authors suggest termination of the procedure when the ﬂuid deficit exceeds 1,000 mL, although other guidelines suggest termination after introduction of 1,500 mL of a nonelectrolyte solution or 2,000 mL of an electrolyte solution (145). Electrolytes should be assessed and corrected if necessary and diuretics considered. Risk factors for ﬂuid overload include resection of fibroids with deep intramural extension or prolonged operating time. The use of normal saline combined with bipolar energy reduces the risk of hyponatremia, but a ﬂuid deficit over 1,500 mL can lead to cardiac overload (146).