In my experience there can be failure to perform this and other similar endometrial ablation
procedures e.g uterine balloon therapy
when the instrument has not entered the uterine cavity
at all. Sometimes, by mistake, it remains in the cervical canal without negotiating the internal opening of the uterus called the internal os. Naturally the mesh or balloon won't open up as the cervical canal tissue is less elastic and distensible than the uterus tissues.
This dificulty in entering the main body of the uterus can occur if the cervical canal is tortuous or angled sharply in front of behind (acutely anteverted/anteflexed or retroverted/retroflexed uterus). Or else the cervical canal may be tightly closed/stenosed.
However, if one is alert to this possibilty and endeavours to negotiate the canal with patience and progressive dilatation, it is possible to overcome this difficulty. Another try under general anaesthesia
in the operation theatre rather than as an Out Patient Procedure may be worth it.
Rarely the uterus may be inelastic due to more fibrous tissues than muscles due to previous surgery on the uterus or infections in the past or very rarely may indicate an underlying collagen tissue disorder
like Systemic Lupus Erythrematosis (SLE). There is no real way to overcome this problem to ensure a successful endometrial ablation procedure.
Heavy, irregular periods
generally are due to PCOS (Poly Cystic Ovarian Syndrome) and both - the heavy period and the irregularity can be corrected by use of hormones - progestrogens alone or in combination with estrogen as in the contraceptive
pills. Newer medications like Ormeloxifene help greatly in reducing the flow but do not correct the irregularity. In that sense Novasure too can decrease the flow but cannot make the periods regular.
Hope this answers your queries adequately.