Veins…At the Receiving End of a Raw Deal?
Advances in arterial surgery and research have been “palpably” more rapid compared to venous surgery especially since 1980. The reasons that have been cited behind this are the frequently unsatisfactory outcomes and perceived lack of “pleasing” end points from the surgeon’s point of view in case of venous surgeries. Having limb-saving and life-saving potential, arterial surgery on the other hand, is perceived to be more satisfying by vascular surgeons in general.
Here are some accepted ‘facts’ in the understanding of the venous system in general. Venous anatomy varies more widely than arterial anatomy. Many venous tributaries are inconsistent and therefore unnamed. Superficial veins (subcutaneous) can be divided and ligated with impunity. Venous blood somehow finds alternative pathways. Veins may recanalize as well. Arteries ‘supply’ blood whereas; the veins (and the lymphatics) ‘drain’ the blood. So, when one mentions ‘blood supply’, one tends to automatically think of arterial supply and not the venous drainage.
Veins however , do assert their importance in certain situations. Example : several major fractures wherein a compartment syndrome develops, when a limb or a part of a limb needs to be re-implanted or in organ transplant surgery.
I will try and use the example of the parathyroid gland to stress the point I wish to convey. Ask any student about the blood supply to the parathyroid gland. Unless pointedly questioned, most students would tell you only the arterial supply! Arterial supply is more or less constant. The venous drainage is less well understood and books may vary in their description. Here are some examples. Parathyroid venous drainage occurs predominantly via the inferior thyroid vein. Via ipsilateral superior middle and inferior thyroid veins. Venous blood from parathyroids drains to the plexus of anterior thyroid veins, and then returns through the superior, middle or inferior thyroid veins .
The rate of temporary hypocalcemia following thyroidetomies is reportedly 2-53%. Risk is more following total thyroidectomy. This may occur even following the most meticulously performed “parathyroid- preserving” total thyroidectomy. The cause of transient hypocalcemia after surgery is not fully understood. One of the causes is believed to be reversible ischemia to the parathyroid glands.
It is not my intention to discuss this complication in detail here. Although, the surgeons endeavor to preserve the ‘blood supply’ (arterial supply, I believe) of the parathyroid glands, venous drainage hardly ever gets a mention. It may the on account of the fact that there is precious little unanimity about the exact anatomy of the parathyroid veins. Although many reasons are cited as to how the parathyroid ‘blood supply’ is compromised, it is glaringly obvious that there is no mention of loss of parathyroid venous drainage (without involvement of the arterial supply) as a possible mechanism. A parathyroid without its venous drainage is no more an endocrine gland by definition. I urge readers to think about this. I concede that it may not be practicable to preserve the venous drainage of the parathyroid glands. My contention is that we tend to ignore the veins as usual.
At present, veins certainly get noticed around examination time, as a “long” or a “short” case – because of ready availability of varicose veins and venous ulcers. Students are extensively queried about the various tourniquet tests (although they are of little practical value today) and the exotic names of some of the tributaries. Apart from this, do the veins deserve a better deal? I suppose, only time can tell………
About the Author: Dr. Aroon Kamath is a retired general surgeon from Puttaparthi, Andhra Pradesh, India. He retired as an Assistant Professor from the Father Muller Medical College, Mangalore, India. He holds interested in teaching as well as medical quiz. He can be reached at: [email protected]
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