Shrinkage of specimens after CO₂ laser cordectomy: an objective intraoperative evaluation

The margin status after CO₂ laser cordectomy for glottic carcinoma may influence prognosis. There are no studies assessing the possible bias due to anatomic changes of the specimens for shrinkage. The authors evaluated the intraoperative shrinkage of specimens immediately after transoral CO₂ laser microsurgery (CO₂ TOLMS) to improve the understanding and the interpretation of surgical margins.

This is a prospective study involving a consecutive cohort of 23 patients (19 males, 4 females, mean age 69.9 years, range 42-83 years) with early glottic carcinoma treated by CO₂ TOLMS from February 2017 to April 2019. The anteroposterior shrinkage of the specimen, of the tumor, and of the anterior and posterior margins was measured intraoperatively with a cross table reticle glass micrometer ruler, inserted into the eyepiece of the surgical microscope.

The mean shrinkage of the mucosal specimen from intralaryngeal measurement to post-resection measurement was 3.8 ± 0.3 mm, resulting in an average loss of 29% of the anteroposterior length (p < 0.01). The anteroposterior length of both the tumor and the margins after resection significantly decreased, but the shrinkage of the anterior and posterior margins was significantly greater than the shrinkage of the tumor (49% versus 20% and 45% versus 20%, p < 0.01).

The present study demonstrates significant shrinkage of specimens after CO₂ TOLMS, especially in the anteroposterior length of the vocal cords, and justifies the good oncological results for specimens with close and single positive superficial margins. Follow-up versus a second surgical look policy could be safely suggested in cases of close superficial and single positive superficial margins.