Thymectomy

Thymectomy
Intervention
ICD-9-CM	07.8
MeSH	D013934
[]

A thymectomy is an operation to remove the thymus. It usually results in remission of myasthenia gravis with the help of medication including steroids. However, this remission may not be permanent. Thymectomy is indicated when thymoma are present in the thymus. Anecdotal evidence suggests MG patients with no evidence of thymoma may still benefit from thymectomy, thus the procedure is (unless and until a much-discussed clinical survey ever reaches a contraindicatory conclusion) commonly prescribed.

There are a number of surgical approaches to the removal of the thymus gland: transternal (through the breast bone), transcervical (through a small neck incision), transthoracic (through one or both sides of the chest.)

There has been no difference in success in symptom improvement between the transsternal approach and the minimally invasive transcervical approach.

Video-assisted approaches, such as laparoscopic surgery, are increasingly prescribed since the less invasive nature of the procedure strikes a balance with the lack of actual clinical evidence supporting thymectomy in non-thymomal cases.

A thymectomy is mainly carried out in adults as the thymus loses most of its functional capacity after adolescence, but does retain a small portion of its function during adulthood. This is shown in the decreasing size of the thymus with increasing age after adolescence.

The role of the thymus prior to adolescence is for the processing and maturation of thymocytes, which become T-lymphocytes and are released into the circulation. They then populate the lymphoid organs for storage until needed. Removal of the thymus as an adult has little immediate effect on the immune system as its role has been completed.

Thymic hypoplasia as may be seen in DiGeorge syndrome results in no T-cell education, and therefore a severe compromise in T-cell-mediated and humoral responses.

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