Chronic subdural hematoma treated by subdural-pleural shunt.

561 Dn. RAN50H0FF: I want to draw your attention to a group of infants with chronic subdural hematoma. The distinctive feature of these patients is marked enlargement of the skull. This megabocephaly was of such a degree in eight patients we treated that they were all admitted to the hospital with a tentative diagnosis of internal hydrocephalus. The presence of subdural hematoma was only discovered in these children at the time of tipping the subdural space through the enlarged antenor fontanelle prior to carrying out ventriculography. When air is injected into the subdural space in these patients, roentgenograms reveal fairly normal-sized cerebral hemispheres surrounded by hugely distended subdural spaces. We believe that it is this disproportion between the size of the boney vault and the size of the underlying brain which makes this group a special therapeutic problem (Fig. 1). When a surgeon drains blood and fluid from the subdural space, he expects the underlying compressed brain to re-expand and obliterate the remaining cavity. If the lesion is of long standing, he may find it necessary to remove the inner membrane of the subdural hematoma, which is covering the surface of the brain, before the expected re-expansion can occur. However, when the cranium has been so enlarged by bilateral subdural collections that it is considerably larger than the normal-sized brain, the brain cannot be expected to reexpand sufficiently to fill the entire cavity. We became aware of this therapeutic dilemma after applying the usual techniques of treatment to a 3-month-old infant admitted in 1952 with a definite history of trauma. After the removal of about 350 ml of subdural fluid by daily subdural taps, we made bone flaps, bilateral and frontoparietal, and removed the inner membranes of the subdural hematomas, 1 week apart. Following recovery from the second operative procedure, the patient again showed signs of increased intracranial pressure and repeat subdural taps showed persistence of the hematomas. An additional 850 ml were withdrawn from the left and right subdural spaces on alternate days, and the left craniotomy was reopened before we carried out a subdural-pleural shunt. This patient was completely studied for any bleeding tendency without abnormal findings (Case F.F. in Table I). The operative technique is quite similar to that which we employ in carrying out a yentriculo-pleural shunt in the treatment of hydrocephalus. In spite of the fact that in the majorit of large subdural collections in infants the subdural spaces communicate from one side to the other under the falx cerebri, it is my opinion that both spaces should be drained in order to assure the greatest chance of suecess. We have achieved bilateral subdural drainage by the use of the usual gum-rubber “T” tube employed for gall bladder drainage. The inside diameter of this tubing is 4 mm. The patients are anesthetized with nitrous oxide, intratracheally, supplemented by sodium pentothal, intravenously. Figure 2 is a diagrammatic representation of the operative procedure. The two short ends of the “T” tube are inserted into the subdural spaces through bilateral occipital-parietal burr holes, the junction point of these having already been buried lower in the subcutaneous tissue of the occipital region. The single end of the “T” tube is tunneled subcutaneously along the posterolateral thoracic wall to the region of the fourth or fifth intercostal space. At this point, through an intercostal approach, the tube is inserted for 4 or 5 cm into the pleural space. The procedure is thus carried out through four small incisions (two in the occipito-parietal region, one in the suboccipital and one in the thoracic area). The patients are maintained with the head elevated at all times in the postoperative period, thus achieving constant drainage of the subdural hematomas.