Fig. 222.—Tail-like Appendage over Spina Bifida Occulta in a boy æt. 5, and associated with incontinence of urine. Operation was followed by temporary retention.
The clinical importance of spina bifida occulta lies in the fact that it is sometimes associated with congenital club-foot, and with nerve symptoms, in the form of sensory, motor, and trophic disturbances referable to the lower limbs, such as perforating ulcer, and to the sphincters. These nerve symptoms usually result from the presence of a tough cord composed of connective tissue, fat, and muscle, stretching from the skin through the vertebral canal to the lower end of the spinal cord. As this strand of tissue does not grow in proportion with the body, in the course of years it drags the cord against the lower border of the membrana reuniens, which closes in the vertebral canal posteriorly. These symptoms may be relieved by the removal of this strand of tissue from the gap in the vertebral arches, or by incising the membrana reuniens.
Congenital Sacro-coccygeal Tumours—Teratoma.—Many varieties of congenital tumours are met with in the region of the sacrum and coccyx. The majority are developed in relation to the communication which exists in the embryo between the neural canal and the alimentary tract—the post-anal gut or neurenteric canal. Some are evidently of bigerminal origin, and contain parts of organs, such as limbs, partly or wholly formed, nerves, parts of eyes, mammary, renal, and other tissues.
Among other tumours met with in this region may be mentioned: the congenital lipoma—a small, rounded, fatty tumour which often suggests a caudal appendage ([Fig. 222]); the sacral hygroma, which forms a sessile cystic tumour growing over the back of the sacrum, and is believed to be a meningocele which has become cut off in utero by the continued growth of the vertebral arch; dermoids, sarcoma, and lymphangioma.
Fig. 223.—Congenital Sacro-coccygeal Tumour.
(Photograph lent by Sir George T. Beatson.)
The treatment consists in removing the tumour, as from its situation it is exposed to injury, and this is liable to be followed by infection. From the position of the wound, and the fact that many of these tumours extend into the hollow of the sacrum and therefore necessitate an extensive dissection, there is considerable risk from infection, especially in young children. The risk is increased when the tumour communicates with the vertebral canal.