NBI and laparoscopic identification of superficial endometriosis

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Use of narrowband imaging (NBI) during laparoscopy to investigate pelvic pain is advantageous in detecting additional areas of endometriosis not identified by standard white light, according to a prospective cohort trial.

The study, which was conducted at a tertiary laparoscopic subspecialty unit in Melbourne, Australia, found that the additional predictive value of NBI was 0% (if the preceding white-light survey was negative) and 86% (if the previous white-light survey was positive).

The trial, which appears in The Journal of Minimally Invasive Gynecology, analyzed 53 premenopausal women (average age 30 years with an average body mass index of 24.4 kg/m²) who underwent operative laparoscopy for investigation of pelvic pain between September 2014 and October 2015.

Overall, 45% of patients were on some type of hormonal treatment. In addition, 36% had previously undergone laparoscopy, of whom 50% had been diagnosed with endometriosis.

As for patient pain, 77% reported cyclical pain, 53% noncyclical pain and 36% dyspareunia.

Furthermore, 36% of patients complained of abnormal uterine bleeding and 25% of either associated bowel or urinary symptoms.

White-light laparoscopy identified 32 of the 53 patients as having lesions suspicious for endometriosis, 75% of whom tested positive for endometriosis, based on histopathological evaluation. 

A total of 89 white-light-guided biopsies were performed, of which 77% of white-light lesions were positive for endometriosis.

In all, 21% of the cohort had a single additional area of suspicion detected with NBI, of whom 55% were positive for endometriosis.

Of the 21 patients who had a negative laparoscopy with white light, only three had a single suspicious lesion identified by NBI. Moreover, all three tested negative for endometriosis on histopathology, thus providing an additional positive predictive value (PPV) of 0% for NBI after white-light survey. 

Of the 32 patients who had suspicious lesions identified with white light, 22% had a single additional area of suspicion detected with NBI. Six of these seven suspicious lesions tested positive for endometriosis, rendering an additional PPV of 86%, if endometriosis is suspected on white-light survey.

There were no complications from surgery for any study patient. 

Histolology on the eight patients with white-light biopsies who were negative for endometriosis revealed three specimens as connective tissue, two as fibroadipose tissue, and one each of an epithelial cyst, normal peritoneum, and fibromuscular tissue with calcification.

Likewise, only two of these eight patients had a previous surgery for investigation of endometriosis.

Of the five patients with NBI biopsies who were negative for endometriosis, histology concluded that two patients had fibroadipose tissue, whereas there was one case each of fibrous peritoneal tissue, fibromuscular tissue with an old hemorrhage, and mesothelial-lined fibromuscular tissue.

Two of these five patients also had a prior surgery for investigation of endometriosis.

Employing NBI after endometriosis has been suspected by white-light survey “would provide patients the best chance of maximal resection of endometriosis and its subsequent benefit while minimizing unnecessary dissection and surgical risk,” the authors wrote.

But the investigators noted that the potential benefits of NBI needs to justify the capital and services costs.

On the other hand, compared to many other imaging modalities for enhancing detection of endometriosis at laparoscopy, NBI does not require medication, therefore avoiding possible side effects and cost of medication.

NBI can also be used through 5-mm ports and with straight-stick laparoscopy, thus bypassing robotic technology or larger ports and incisions.