Excision vs Ablation for Endometriosis: What Each Technique Is and What the Evidence Says

What excision is

Excision means removing the lesion and a thin margin of tissue around it. The surgeon lifts the peritoneum (the lining of the pelvis), cuts around the lesion, and separates it from the structures underneath. Removed tissue goes to a pathologist, who confirms under the microscope that it is endometriosis. For an ovarian cyst (endometrioma), excision means stripping the cyst wall out of the ovary rather than draining it.

The strength of excision is completeness: the surgeon can follow a lesion as deep as it goes, including into the ligaments behind the uterus or the wall of the bowel. The cost is that it takes longer and demands more skill, especially near the ureter, bowel and large vessels. "Excision surgery" and "wide excision" are other names for the same thing.

What ablation is

Ablation destroys the lesion where it sits. The surgeon applies heat (electrosurgery or "diathermy"), a laser beam or plasma energy to the surface until the visible lesion is gone. Nothing is removed, so there is no tissue for pathology. It is quick and needs little dissection, which is why it is widely used for small superficial spots found during a diagnostic laparoscopy.

The limitation is depth. Energy penetrates a few millimeters at most, so a deeper lesion is burned on top and left underneath. Near the bowel, bladder or ureter, surgeons also limit the energy they use to avoid thermal injury.

What the randomized trials show

Only a few randomized trials have compared the two techniques directly, and they studied women with superficial (minimal to mild) disease. The largest, by Healey and colleagues in Australia, randomized women with visually confirmed endometriosis to excision or ablation and followed pain scores for five years. Pain fell in both groups. At five years, deep pain with sex (dyspareunia) improved more after excision (p = 0.03), and more women in the ablation group were still taking medical treatment for endometriosis (p = 0.004). Other pain symptoms did not differ significantly.

Two meta-analyses pooled these trials with different emphases. Pundir and colleagues (2017) combined three trials with 335 participants and reported greater improvement with excision in pain with bowel movements (mean difference 1.31 points on a 10-point scale, p = 0.009) and, in one trial, in chronic pelvic pain (mean difference 2.57 points). Period pain was borderline (p = 0.05) and pain with sex trended toward excision without reaching statistical significance. A 2024 expression of concern from the journal questions this analysis, so weight it accordingly. Burks and colleagues (2021) pooled four trials with 346 participants, with follow-up from 6 to 60 months, and found no significant difference between excision and ablation for period pain, pain with bowel movements or pain with sex at 12 months or later.

The 2020 Cochrane review of laparoscopic surgery for endometriosis, covering 14 trials and 1,563 women overall, found only one trial of 103 women that could inform the excision-versus-ablation comparison for overall pain at 12 months. The difference was zero (mean difference 0.00, 95% confidence interval -1.22 to 1.22), the evidence was rated very low quality, and the authors concluded there is not enough evidence to say whether one technique controls overall pain better than the other.

Why the evidence is still uncertain

• The trials are small. Every pooled analysis rests on a few hundred women, so a moderate real difference could be missed.
• They studied superficial disease. Women with deep nodules, bowel involvement or large endometriomas were not randomized.
• In the Healey trial, supervised trainees were the primary surgeons. Results in a specialist practice could differ in either direction.
• Pain was self-reported on 10-point scales, and recurrence was measured mainly by symptoms, not by repeat surgery.
• The two meta-analyses pooled different trials and time points, which is partly why they disagree. Both called for larger, longer trials.

When ablation is commonly used

Ablation is often chosen for small, superficial peritoneal lesions found during a laparoscopy done for another reason, for example an evaluation for infertility, or when excising a spot would mean dissecting next to a vital structure for little gain. In the Cochrane review, laparoscopic treatment of any kind probably improves the chance of a viable pregnancy compared with diagnostic laparoscopy alone (odds ratio 1.89, 3 trials, 528 women, moderate-quality evidence), and much of that treatment was ablation of mild disease.

For ovarian endometriomas, NICE NG73 advises considering excision rather than ablation. The NICE guideline (NG73) advises considering excision of the cyst wall rather than ablation, taking into account the woman's fertility plans and ovarian reserve, because drainage and ablation leave cyst lining behind and the cyst tends to return.

Why deep or bowel disease changes the picture

Deep endometriosis is defined as lesions that infiltrate more than 5 millimeters under the peritoneal surface. Nodules in the uterosacral ligaments, between the rectum and vagina, or in the bowel, bladder or ureter are deep by definition. Burning the surface of such a nodule leaves most of the disease in place, which is why the comparison trials excluded them and why the ESHRE 2022 guideline recommends that deep endometriosis be treated in centers with the expertise to excise it, often with colorectal or urologic surgeons present. Options for bowel nodules range from shaving the lesion off the bowel to removing a disc or a segment of bowel wall; all of these are forms of excision.

If your imaging or examination suggests deep disease, the practical question is not "excision or ablation" but "does this surgeon treat deep disease to its full depth, and with whom".

What to ask the surgeon

• How many endometriosis operations do you perform each year, and how many involve deep disease?
• Will you excise lesions, ablate them, or both? What decides it during the operation?
• If you find deep disease in the bowel, bladder or ureter, will it be treated at this operation, and is a colorectal or urologic surgeon available?
• Will removed tissue be sent to pathology, and will I receive the report and operative photographs?
• How will you treat an endometrioma: cyst wall removal or drainage and ablation? How will you protect my ovarian reserve?
• What are your rates of bowel, bladder and ureter injury, and of repeat surgery?

Recovery is similar

Both techniques use the same small laparoscopic incisions, so recovery from the incisions is similar: most women go home the same day or the next, return to desk work in one to two weeks, and resume full activity in about four to six weeks. Excision of deep disease, especially bowel surgery, means a longer operation and recovery, with a hospital stay of several days when a bowel segment is removed. Pelvic floor physical therapy can help after either kind of surgery, because muscle guarding built up over years of pain often does not release on its own.