Developmental anatomy of the tonsil and its implications for intracapsular tonsillectomy.

OBJECTIVE

To describe the developmental anatomy of the human tonsil from the embryonic period through adulthood and to use this information to define the applicability of intracapsular tonsillectomy in the management of disease.

DESIGN

Descriptive-anatomic.

SUBJECTS

(1) Normal embryos and fetuses from two archival collections, (2) children with adenotonsillar hypertrophy and (3) adult autopsy material.

RESULTS

The second branchial pouch is visible in the 4th post-conceptional week and demonstrates canalization and branching in the 8th week. Lymphoid infiltration of the lamina propria occurs in the seventh month of intrauterine life. Primary follicles form late in gestation, but germinal center stimulation does not occur until shortly after birth. During the first year of life, there is rapid proliferation of lymphoid elements and formation of active germinal centers. During the phase of maximum tonsillar hyperplasia, the lymphoid elements proliferate rapidly, increasing tonsillar bulk. In senescence, there is involution of the lymphoid elements and proliferation of fibrous tissue in the capsule and trabeculae. The overall bulk of the tonsil is much decreased.

CONCLUSIONS

There is an intimate relationship between the epithelial and lymphoid components of the tonsil which continues through life. To adequately control upper airway obstruction of tonsillar origin and recurrent tonsillar infection in childhood, total or near total intracapsular tonsillectomy likely will prove the minimum acceptable surgical intervention. Changes in tonsillar anatomy after the first decade may alter operative choice in older patients.