Specimen ultrasound. A possible way of quality control of the TME

Aims: The circumferential resection margin has a vital importance in determining the success of total mesorectal excision. There has been a debate, wheather the pathologist measures the real distance between the tumour and the margin, or it has been shrank by the formaline. Using the endo-rectal ultrasound we tried to measure the clearance between the tumour an the resection margin in the operating theatre.

Material and methods: We used rectal specimens, that had just been removed during rectal resections. After a thorough washout we immersed them in a saline bath and used the B and K Leopard ultrasound machine with the hard top endo-rectal probe to complete the investigation. It was carried out intraluminally, underwater. The extent of the tumour was assessed, together with the mesorectal volume and the continuity of the mesorectal fascia. The nearest points between the fascia or the cut surface and the tumour edge were noted and measured. The specimens than were studied by the pathologist as usual following formaline fixation.

Results: 11 specimens were investigated. The tumour extent, and the mesorectal volume was easily definable in all cases. Detectable dehiscences on the mesorectal fascia were present in 4 cases. There were 2 cases when the tumour reached or was within 1mm of the fascia.

Conclusion: Specimen ultrasound seems to be a promising method for determining the quality of the TME. Since it is carried out in or near the operating theatre right after the specimen has been removed, it can give a prompt feedback to the surgeon. It can also help the pathologist to identify the points of interest in the specimen.