A reply

Abstract

Thank you very much for the opportunity of replying to Dr. Mihai and Mr Sadler from Oxford. The extent of retrosternal extension does not necessarily correlate with the presence or absence of venous obstruction; thus we did not feel obliged to report the degree of extension in our cases. For the record, in two cases the lowest extent of the goitre was at the upper level of the arch and in the other it was level with the arch. We have removed many thyroid goitres that have been well below the arch (and even straddling each side), that have not presented with venous obstruction, and that were all removed successfully and safely via the cervical route. Again, for the record, all cytology performed on our cases’ thyroids proved benign pre-operatively. We agree with Mihai and Sadler’s comments that the airway management is likely to be more challenging in cases of locally advanced cancer. Nevertheless, even with large benign goitres, induction of general anaesthesia in the supine position plus initiation of positive pressure ventilation can exacerbate the extrinsic airway compression and cause further large airways collapse. With regard to the intra-operative measurement of venous pressure, we would like to point out that ours is a small series of practically managed cases, and not a large well-funded scientific study. The fact that there was caudal flow in all the extra-corporeal grafts was itself proof of effect (rather than a ‘surrogate index’); a graft under normal physiological circumstances would demonstrate no flow. We demonstrated significant increases in both peak systolic and end-diastolic velocities in the common femoral vein on unclamping of the venous bypass shunt using Doppler ultrasound in our patients. The comments on intra-operative blood loss are well founded, and we agree entirely, though we would also like to add that a major potential source of intra-operative blood loss is from the goitre itself; if a goitre is engorged with blood, as it will be in superior vena caval obstruction, then this bleeding may be severe. Decompression using our technique will effectively abolish this and render the gland smaller and more amenable to removal through the cervical route, as we have indicated in our paper. Our experience with blood transfusion requirement is similar, in that none of our massive retrosternal goitres have required transfusion, and none have been returned to theatre (for any reason). It is a pity that Mihai and Sadler cannot accept our message. They appear to over-emphasise the risk of haemorrhage from the veno-venous bypass, which is simple to perform and requires only a small incision in the groin (the jugular approach effectively being incorporated in the cervical incision). This risk is negligible, particularly when compared to that of an unnecessary thoracotomy, which Mihai and Sadler appear keen to perform in such cases. There are always potentially different solutions to the same clinical problem. We agree that the occasional thoracic and endocrine surgeon may prefer a different approach to the experienced vascular and endocrine surgeon.