ACTA NEUROCHIRURGICA
Acta Neurochirurgica 45, 217--224 (1979)
9 by Springer-Verlag 1979
Division of Neurosurgery * and Division of Neuroradiology **, The University of Texas Medical School at Houston, Houston, Texas, U.S.A. CT
Scanning
After Drainage
Haematoma: An Unusual
of Subdural Case
By H. H. K a u f m a n * and S. F. H a n d e l * * With 5 Figures
Summary A unique patient with bilateral subdural haematomas with localized subdural membranes on one side is reported. Serial CT scans suggested that the membranes resolved spontaneously after drainage of the haematoma. The pathophysiology of subdural haematoma and the value of CT scanning in postoperative follow-up are discussed, especially in regard to learning more about the optimal treatment in this still somewhat enigmatic problem. Key words: Subdural haematoma; computerized axial tomography. A case o f persistent subdural membranes on one side after evacuation o f bilateral chronic subdural h a e m a t o m a s is reported. The unique aspect of this case, which is n o t explained, is the localized nature of the membranes. This case a n d a review o f the literature p o i n t out the value o f f o l l o w - u p C T scanning in patients after drainage o f subdural h a e m a t o m a s a n d the fact t h a t there are still u n a n s w e r e d questions concerning the t r e a t m e n t o f this condition.
Case Report A 74-year-old black female presented with a two month history of forgetfulness and unsteady gait, and increasing somnolence for one week. Although drowsy, she was orientated and able to answer questions. Funduscopic examination was unremarkable. The only focal finding was a minimal right facial weakness. Skull X-rays were unremarkable. Lumbar puncture revealed normal pressure, and the only abnormality on CSF analysis was a slightly elevated protein of 77 mg~ CT scan showed bilateral peripheral low density zones, slightly larger on 0 0 0 1 - 6 2 6 8 / 7 9 / 0 0 4 5 / 0 2 1 7 / 8 01.60
Fig. 1. CT scan following contrast infusion showing bilaterai peripheral low-density zones with medial contrasting rims (arrow)
Fig. 2. CT scan 13 days following surgery. Subdural air is present (arrow) and the lateral ventricles are displaced (arrowhead)
H. H. Kaufman et al. : CT Scanning After Drainage of Haematoma
219
the left, with thin medial rims of increased density. The rims enhanced slightly with contrast (Fig. 1). The findings were felt to demonstrate bilateral haematomas. Bilateral frontal and parietal trephinations were performed, and large subdural collections of machine-oil-like material were evacuated from both sides. No membranes were seen. The brain did not re-expand. Postoperatively, the patient's mental state returned to normal, and she was up and about. She continued to have a slight right central facial weakness. CT scans obtained six, ten, and thirteen days postoperatively revealed a persistent left subdural space partially filled with air and a 5 mm shift of the midline structures from the left to the right (Fig. 2 and 3).
Fig. 3. CT scan at a higher level than Fig. 2 demonstrating an extracerebral lowdensity zone with a medial rim (arrows)
Injection of contrast material did not result in enhancement. Two attempts to aspirate fluid through the left frontal burr hole were unsuccessful. Due to the persistent large extracerebral collection which seemed to lie between the two left trephination sites, and because the patient lived alone and would not be under observation, it was decided to re-explore the left subdural space. Under local anaesthesia, a new burr hole was placed over the centre of the lesion and revealed a laminated subdural membrane almost 2 cm thick, but no fluid. As there did not appear to be any increased pressure in the intracranial compartment, it was decided to terminate the operation and follow the membranes with further scans. The patient was discharged and followed. Another CT scan obtained one month later did not demonstrate a subdural space, and the ventricles were in normal position (Figs. 4 and 5).
Fig. 4
Fig. 5 Figs. 4 and 5. CT scans one m o n t h following discharge at which time the extracerebral low-density zone and medial rim are no longer present. The ventricles are midline in position
H. H. Kaufman et
al.:
CT ScanningAfter Drainage of Haematoma
221
Discussion
The pathophysiology and evolution of subdural haematomas and membranes have been extensively studied. The haematomas mature from a jelly-like clot to brownish to yellow-brown liquid. At the same time, membranes develop, initially under the dura. By two weeks, a visible inner membrane may be seen over the surface of the brain. Often the membranes become more dense and hyalinized, while their vascularity may diminish 15, ~1 The CT appearance of "chronic" subdural haematomas, which are characteristically of low density, has been discussed by several authors 3, 5, 27. It has been shown that in some cases contrast enhancement may demonstrate the subdural membranes 23, 27 The reasons why some haematomas may persist and enlarge and others may disappear have recently been studied in detail, both clinically and in experimental models, and the literature reviewed. In one ongoing investigation growth of new capillaries with enhanced permeability related to inflammation and fibrinolytic alterations within the subdural haematoma have been shown to be two (possibly interrelated) features of vital importance. It was also suggested that there may be a critical size of the haematoma that is important for its growth or disappearance 4, 11, J2, 13 Other studies also suggest that hyperfibrinolysis with secondary haemorrhages may contribute to haematoma enlargement 7, 8 Although chronic subdural haematomas have been treated by craniotomy and excision of membranes, simple drainage through small bony openings, with external drainage if the brain does not reexpand, was described as early as 1914 35. Drainage can even be accomplished through twist drill holes performed at the bedside 3~ Most evidence of the effectiveness of simple drainage is clinical in nature. The fate of the membranes has not always been known 28, ~2, 83, 86, though mention of operative observation of their disappearance after simple drainage was mentioned in 1932 is. In one series, serial biopsies were done in patients with internalized subdural drains. These revealed decreases in vascularity and cellularity in the membranes with maturing fibroblastic change and, in one case, complete disappearance of the membrane 2. Persistence of the subdural space and the midline shift after evacuation of the subdural haematoma in our patient were not totally unexpected findings. Indeed, repeated subdural taps in children with chronic subdural haematomas are often productive of fluid for a long period, and although serial taps are usually sufficient treatment, internal shunts may be needed 2, 20, 22, 28, 86 It is not clear whether
222
I-I. H. Kaufman and S. F. HandeI:
serial taps are always necessary or whether the fluid in some cases eventually would resolve spontaneously once an initial tap is done. Also, serial skull X-rays with silver clips left on the cortex 24, 80 or serial angiograms 10, 19. 20 after evacuation of chronic subdural haematomas reveal that obliteration of the subdural space and return of the midline structures to midposition takes a variable period of time, but intervention has been said not to be required if the patient is improving clinically. One study following patients postoperatively with CT scans showed similar findings 6. The reasons for the eventual obliteration of the subdural space are not completely understood, although they undoubtedly relate to reabsorption of fluid as well as primary or secondary maturation and regression of membranes 20, 21 On the other hand, two active approaches have been used to promote the resolution of a persistent subdural space-drainage of its contents and inflation of the ventricles. Some have suggested that temporary drains be left postoperatively z.2, aa, 34, and sophisticated closed drainage systems have been developed which should carry less risk of infection 9, iv. Others have advocated that repeated subdural taps should be employed for persistent subdural collections 12, 25, a0, 86 The placement of internal shunts might also be utilized in adults as it has been in children (vide supra). The other approach is to expand the brain by inflating the ventricles at the time of surgery. This can be done by infusing mock CSF into the ventricles 1t, 29 or lumbar subarachnoid space 14, 16, 26. a0 at the time of surgery and even repeatedly thereafter ~r We feel that postoperative CT scans are indicated after drainage of chronic subdural haematomas, no matter what type of treatment is employed, until the anatomical relationships of the brain are normalized to confirm an adequate response to therapy, as has been suggested by the Joint Materials and Devices and Socio-Economics Committees of the A A N S 1. The indications for postoperative drainage or taps might also be established through studies using serial CT scans. In addition, it could be determined if infusions of mock CSF are helpful. The uniqueness of our case relates to the fact that the subdural membranes were well localized. It would have been expected that the membranes would have spread across the dura in relation to the entire fluid collection, and it is not clear why such a thick but welllocalized membrane was formed. This case is reported both because of this interesting finding and because we were able to use CT scanning to follow the presumed resolution of this membrane.
CT Scanning After Drainage of Subdural Haematoma
223
References
1. Burton, C.V., Neurosurgical devices and drugs. Neurosurgery 1 (1977), 170--173. 2. Collins, W.D., Pucci, G.L., Peritoneal drainage of subdural hematomas in infants. J. Pediatr. 58 (1961), 482--485. 3. French, B.N., Dublin, A.B., The value of computerized tomography in the managment of 1,000 consecutive head injuries. Surg. Neurol. 7 (1977), 171--183. 4. Glover, D., Labadie, E. L., Physiopathogenesis of subdural hematomas. Part 2: Inhibition of growth of experimental hematomas with dexamethasone. J. Neurosurg. 45 (1976), 393--397. 5. Grumme, Th., Lanksch, W., Kazner, E., Hulich, A., Meese, W., Lange, S., Steinhoff, H., Wende, S., Zur Diagnose des Chronischen Subduralen H~imatoms im Computer-Tomogramm. Neurochirurgia (Stuttg.) 19 (1976), 95--103. 6. Haar, F., Lott, T.M., Nichols, P.J., The usefulness of CT scanning for subdural hematomas. Neurosurg. 1 (1977), 272--275. 7. Ho, H., Yamamoto, S., Komai, T., Nuzukoshi, H., Role of local hyperfibrinolysis in the etiology of chronic subdural hematoma. J. Neurosurg. 45 (1976), 26--31. 8. Ito, H., Komai, T., Yamamoto, S., Fibrinolytic enzyme in the lining walls of chronic subduraI hematoma. J. Neurosurg. 48 (1978), 197--200. 9. Jackson, F. E., Pratt, R. A., Technical report: A silicone rubber suction drain for drainage of subdural hematomas. Surgery 70 (1971), 578--579. 10. Kristiansen, K., Cerebral angiography in the diagnosis of intracranial hematomas. Surgery 24 (1948), 755--768. 11. Labadie, E. L., Glover, D., Physiopathogenesis of subdural hematomas. Part 1: Histological and biochemical comparisons of subcutaneous hematoma in rats with subduraI hematoma in man. J. Neurosurg. 45 (1976), 382--392. 12. Labadie, E. L., Glover, D., Local alterations of hemostatic-fibrinolytic mechanisms in reforming subdural hematomas. Neurology 25 (1975), 669--675. 13. Labadie, E. L., Glover, D., Chronic subdural hematoma: concepts of physiopathogenesis. A review. Canad. J. Neurol. Sci. 1 (1974), 222--225. 14. LaLonde, A.A., Gardner, W.J., Chronic subdural hematoma. Expansion of compressed cerebral hemisphere and relief of hypotension by spinal injection of physiologic saline solution. New Engl. J. Med. 239 (1948), 493--496. 15. Levy, L. R., Subdural haematoma. East Afr. Med. J. 35 (1958), 345--356. 16. Lewis, R.C., Elliot, K. A. C., Clinical uses of an artificaI cerebrospinal fluid. J. Neurosurg. 7 (1950), 256--260. 17. Matricali, B., Subdural suction drainage of subdural haematomas. Surg. Neurol. 3 (1975), 245--246. 18. McKenzie, K.G., A surgical and clinical study of nine cases of chronic subdural haematoma. Canad. Med. Ass. J. 26 (1932), 534--544. 19. McLaurin, R.L., Contributions of angiography to the pathophysiology of subdural hematomas. Neurology 15 (1965), 866--873. 20. McLaurin, R.L., Repeated aspiration as the preferred treatment of subdural hematomas in infants. In: Current Controversies in Neurosurgery, pp. 561--565 (Morley, T. P., ed.). Philadelphia: W. B. Saunders Co. 1976. 21. McLaurin, R.L., Isaacs, E., Lewis, P. H., Results of nonoperative treatment in 15 cases of infantile subdural hematoma. J. Neurosurg. 34 (1971), 753--759. 22. Moyes, P.D., Thompson, G.B., Cluff, J. W., Subdural peritoneal shunts in the treatment of subdurat effusions in infants. J. Neurosurg. 23 (1965), 584--587. 23. New, P. F.J., Scott, W.R., Computed tomography of the brain and orbit. pp. 296--297. Baltimore: Williams and Wilkins. 1975.
224
H . H . Kaufman et al.: CT Scanning After Drainage of Haematoma
24. Parkinson, D., Chochinov, H., Subdural hematoma--some observations on their postoperative course. J. Neurosurg. 17 (1960), 901--904. 25. Rand, R.O., Ward, A.A., Jr., White, L.E., Jr., The use of the twist drill to evaluate head trauma. J. Neurosurg. 25 (1966), 410--415. 26. Robinson, R. G., The treatment of subacute and chronic subdural haematomas. Brit. Med. J. 1 (1955), 21--22. 27. Scotti, G., Terbrugge, K., McLacon, D., Belager, G., Evaluation of the age of subdural hematomas by computerized tomography. J. Neurosurg. 47 (1977), 311--315. 28. Shulman, K., Ranshohoff, J., Subdural hematoma in children. J. Neurosurg. 18 (1961), 175--181. 29. Smyth, H. S., Livingston, K.E., Ventricular infusion in the operative management of subdural hematoma. In: Current Controversies in Neurosurgery, pp. 566--571 (Morley, T. P., ed.). Philadelphia: Saunders. 1976. 30. So, S.C., Chronic subdural haematoma in the eldery. Aust. N.Z.J. Surg. 46 (1976), 166--169. 31. Stehbens, W.E., Pathology of the cerebral blood vessels, pp. 232--251. St. Louis: C. V. Mosby Co. 1972. 32. Svien, J. J., Gelety, J. E., On the surgical management of encapsulated subdural hematoma. J. Neurosurg. 21 (1964), 172--177. 33. Taarnhoj, P., Chronic subdural hematoma. Cleve. Clin. Q. 22 (1955), 150--156. 34. Tabbador, K., Shulman, K., Definitive treatment of chronic subdural hematoma by twist-drill craniostomy and closed system drainage. J. Neurosurg. 46 (1977), 220--226. 35. Trotter, W., Chronic subdural haemorrhage of traumatic origin, and its relation to pachymeningitis haemorrhagica interna. Brit. J. Surg. 2 (1914), 271--291. 36. Yashon, D., Jane, J. A., White, R. J., Sugar, O., Traumatic subdural hematoma of infancy. Arch. Neurol. 18 (1968), 370--377. Authors' address : H. Kaufman, M.D., Division of Neurosurgery, The University of Texas Medical School at Houston, Houston, TX 77030, U.S.A.
Acta Neurochirurgica 45, 217--224 (1979)
9 by Springer-Verlag 1979
Division of Neurosurgery * and Division of Neuroradiology **, The University of Texas Medical School at Houston, Houston, Texas, U.S.A. CT
Scanning
After Drainage
Haematoma: An Unusual
of Subdural Case
By H. H. K a u f m a n * and S. F. H a n d e l * * With 5 Figures
Summary A unique patient with bilateral subdural haematomas with localized subdural membranes on one side is reported. Serial CT scans suggested that the membranes resolved spontaneously after drainage of the haematoma. The pathophysiology of subdural haematoma and the value of CT scanning in postoperative follow-up are discussed, especially in regard to learning more about the optimal treatment in this still somewhat enigmatic problem. Key words: Subdural haematoma; computerized axial tomography. A case o f persistent subdural membranes on one side after evacuation o f bilateral chronic subdural h a e m a t o m a s is reported. The unique aspect of this case, which is n o t explained, is the localized nature of the membranes. This case a n d a review o f the literature p o i n t out the value o f f o l l o w - u p C T scanning in patients after drainage o f subdural h a e m a t o m a s a n d the fact t h a t there are still u n a n s w e r e d questions concerning the t r e a t m e n t o f this condition.
Case Report A 74-year-old black female presented with a two month history of forgetfulness and unsteady gait, and increasing somnolence for one week. Although drowsy, she was orientated and able to answer questions. Funduscopic examination was unremarkable. The only focal finding was a minimal right facial weakness. Skull X-rays were unremarkable. Lumbar puncture revealed normal pressure, and the only abnormality on CSF analysis was a slightly elevated protein of 77 mg~ CT scan showed bilateral peripheral low density zones, slightly larger on 0 0 0 1 - 6 2 6 8 / 7 9 / 0 0 4 5 / 0 2 1 7 / 8 01.60
Fig. 1. CT scan following contrast infusion showing bilaterai peripheral low-density zones with medial contrasting rims (arrow)
Fig. 2. CT scan 13 days following surgery. Subdural air is present (arrow) and the lateral ventricles are displaced (arrowhead)
H. H. Kaufman et al. : CT Scanning After Drainage of Haematoma
219
the left, with thin medial rims of increased density. The rims enhanced slightly with contrast (Fig. 1). The findings were felt to demonstrate bilateral haematomas. Bilateral frontal and parietal trephinations were performed, and large subdural collections of machine-oil-like material were evacuated from both sides. No membranes were seen. The brain did not re-expand. Postoperatively, the patient's mental state returned to normal, and she was up and about. She continued to have a slight right central facial weakness. CT scans obtained six, ten, and thirteen days postoperatively revealed a persistent left subdural space partially filled with air and a 5 mm shift of the midline structures from the left to the right (Fig. 2 and 3).
Fig. 3. CT scan at a higher level than Fig. 2 demonstrating an extracerebral lowdensity zone with a medial rim (arrows)
Injection of contrast material did not result in enhancement. Two attempts to aspirate fluid through the left frontal burr hole were unsuccessful. Due to the persistent large extracerebral collection which seemed to lie between the two left trephination sites, and because the patient lived alone and would not be under observation, it was decided to re-explore the left subdural space. Under local anaesthesia, a new burr hole was placed over the centre of the lesion and revealed a laminated subdural membrane almost 2 cm thick, but no fluid. As there did not appear to be any increased pressure in the intracranial compartment, it was decided to terminate the operation and follow the membranes with further scans. The patient was discharged and followed. Another CT scan obtained one month later did not demonstrate a subdural space, and the ventricles were in normal position (Figs. 4 and 5).
Fig. 4
Fig. 5 Figs. 4 and 5. CT scans one m o n t h following discharge at which time the extracerebral low-density zone and medial rim are no longer present. The ventricles are midline in position
H. H. Kaufman et
al.:
CT ScanningAfter Drainage of Haematoma
221
Discussion
The pathophysiology and evolution of subdural haematomas and membranes have been extensively studied. The haematomas mature from a jelly-like clot to brownish to yellow-brown liquid. At the same time, membranes develop, initially under the dura. By two weeks, a visible inner membrane may be seen over the surface of the brain. Often the membranes become more dense and hyalinized, while their vascularity may diminish 15, ~1 The CT appearance of "chronic" subdural haematomas, which are characteristically of low density, has been discussed by several authors 3, 5, 27. It has been shown that in some cases contrast enhancement may demonstrate the subdural membranes 23, 27 The reasons why some haematomas may persist and enlarge and others may disappear have recently been studied in detail, both clinically and in experimental models, and the literature reviewed. In one ongoing investigation growth of new capillaries with enhanced permeability related to inflammation and fibrinolytic alterations within the subdural haematoma have been shown to be two (possibly interrelated) features of vital importance. It was also suggested that there may be a critical size of the haematoma that is important for its growth or disappearance 4, 11, J2, 13 Other studies also suggest that hyperfibrinolysis with secondary haemorrhages may contribute to haematoma enlargement 7, 8 Although chronic subdural haematomas have been treated by craniotomy and excision of membranes, simple drainage through small bony openings, with external drainage if the brain does not reexpand, was described as early as 1914 35. Drainage can even be accomplished through twist drill holes performed at the bedside 3~ Most evidence of the effectiveness of simple drainage is clinical in nature. The fate of the membranes has not always been known 28, ~2, 83, 86, though mention of operative observation of their disappearance after simple drainage was mentioned in 1932 is. In one series, serial biopsies were done in patients with internalized subdural drains. These revealed decreases in vascularity and cellularity in the membranes with maturing fibroblastic change and, in one case, complete disappearance of the membrane 2. Persistence of the subdural space and the midline shift after evacuation of the subdural haematoma in our patient were not totally unexpected findings. Indeed, repeated subdural taps in children with chronic subdural haematomas are often productive of fluid for a long period, and although serial taps are usually sufficient treatment, internal shunts may be needed 2, 20, 22, 28, 86 It is not clear whether
222
I-I. H. Kaufman and S. F. HandeI:
serial taps are always necessary or whether the fluid in some cases eventually would resolve spontaneously once an initial tap is done. Also, serial skull X-rays with silver clips left on the cortex 24, 80 or serial angiograms 10, 19. 20 after evacuation of chronic subdural haematomas reveal that obliteration of the subdural space and return of the midline structures to midposition takes a variable period of time, but intervention has been said not to be required if the patient is improving clinically. One study following patients postoperatively with CT scans showed similar findings 6. The reasons for the eventual obliteration of the subdural space are not completely understood, although they undoubtedly relate to reabsorption of fluid as well as primary or secondary maturation and regression of membranes 20, 21 On the other hand, two active approaches have been used to promote the resolution of a persistent subdural space-drainage of its contents and inflation of the ventricles. Some have suggested that temporary drains be left postoperatively z.2, aa, 34, and sophisticated closed drainage systems have been developed which should carry less risk of infection 9, iv. Others have advocated that repeated subdural taps should be employed for persistent subdural collections 12, 25, a0, 86 The placement of internal shunts might also be utilized in adults as it has been in children (vide supra). The other approach is to expand the brain by inflating the ventricles at the time of surgery. This can be done by infusing mock CSF into the ventricles 1t, 29 or lumbar subarachnoid space 14, 16, 26. a0 at the time of surgery and even repeatedly thereafter ~r We feel that postoperative CT scans are indicated after drainage of chronic subdural haematomas, no matter what type of treatment is employed, until the anatomical relationships of the brain are normalized to confirm an adequate response to therapy, as has been suggested by the Joint Materials and Devices and Socio-Economics Committees of the A A N S 1. The indications for postoperative drainage or taps might also be established through studies using serial CT scans. In addition, it could be determined if infusions of mock CSF are helpful. The uniqueness of our case relates to the fact that the subdural membranes were well localized. It would have been expected that the membranes would have spread across the dura in relation to the entire fluid collection, and it is not clear why such a thick but welllocalized membrane was formed. This case is reported both because of this interesting finding and because we were able to use CT scanning to follow the presumed resolution of this membrane.
CT Scanning After Drainage of Subdural Haematoma
223
References
1. Burton, C.V., Neurosurgical devices and drugs. Neurosurgery 1 (1977), 170--173. 2. Collins, W.D., Pucci, G.L., Peritoneal drainage of subdural hematomas in infants. J. Pediatr. 58 (1961), 482--485. 3. French, B.N., Dublin, A.B., The value of computerized tomography in the managment of 1,000 consecutive head injuries. Surg. Neurol. 7 (1977), 171--183. 4. Glover, D., Labadie, E. L., Physiopathogenesis of subdural hematomas. Part 2: Inhibition of growth of experimental hematomas with dexamethasone. J. Neurosurg. 45 (1976), 393--397. 5. Grumme, Th., Lanksch, W., Kazner, E., Hulich, A., Meese, W., Lange, S., Steinhoff, H., Wende, S., Zur Diagnose des Chronischen Subduralen H~imatoms im Computer-Tomogramm. Neurochirurgia (Stuttg.) 19 (1976), 95--103. 6. Haar, F., Lott, T.M., Nichols, P.J., The usefulness of CT scanning for subdural hematomas. Neurosurg. 1 (1977), 272--275. 7. Ho, H., Yamamoto, S., Komai, T., Nuzukoshi, H., Role of local hyperfibrinolysis in the etiology of chronic subdural hematoma. J. Neurosurg. 45 (1976), 26--31. 8. Ito, H., Komai, T., Yamamoto, S., Fibrinolytic enzyme in the lining walls of chronic subduraI hematoma. J. Neurosurg. 48 (1978), 197--200. 9. Jackson, F. E., Pratt, R. A., Technical report: A silicone rubber suction drain for drainage of subdural hematomas. Surgery 70 (1971), 578--579. 10. Kristiansen, K., Cerebral angiography in the diagnosis of intracranial hematomas. Surgery 24 (1948), 755--768. 11. Labadie, E. L., Glover, D., Physiopathogenesis of subdural hematomas. Part 1: Histological and biochemical comparisons of subcutaneous hematoma in rats with subduraI hematoma in man. J. Neurosurg. 45 (1976), 382--392. 12. Labadie, E. L., Glover, D., Local alterations of hemostatic-fibrinolytic mechanisms in reforming subdural hematomas. Neurology 25 (1975), 669--675. 13. Labadie, E. L., Glover, D., Chronic subdural hematoma: concepts of physiopathogenesis. A review. Canad. J. Neurol. Sci. 1 (1974), 222--225. 14. LaLonde, A.A., Gardner, W.J., Chronic subdural hematoma. Expansion of compressed cerebral hemisphere and relief of hypotension by spinal injection of physiologic saline solution. New Engl. J. Med. 239 (1948), 493--496. 15. Levy, L. R., Subdural haematoma. East Afr. Med. J. 35 (1958), 345--356. 16. Lewis, R.C., Elliot, K. A. C., Clinical uses of an artificaI cerebrospinal fluid. J. Neurosurg. 7 (1950), 256--260. 17. Matricali, B., Subdural suction drainage of subdural haematomas. Surg. Neurol. 3 (1975), 245--246. 18. McKenzie, K.G., A surgical and clinical study of nine cases of chronic subdural haematoma. Canad. Med. Ass. J. 26 (1932), 534--544. 19. McLaurin, R.L., Contributions of angiography to the pathophysiology of subdural hematomas. Neurology 15 (1965), 866--873. 20. McLaurin, R.L., Repeated aspiration as the preferred treatment of subdural hematomas in infants. In: Current Controversies in Neurosurgery, pp. 561--565 (Morley, T. P., ed.). Philadelphia: W. B. Saunders Co. 1976. 21. McLaurin, R.L., Isaacs, E., Lewis, P. H., Results of nonoperative treatment in 15 cases of infantile subdural hematoma. J. Neurosurg. 34 (1971), 753--759. 22. Moyes, P.D., Thompson, G.B., Cluff, J. W., Subdural peritoneal shunts in the treatment of subdurat effusions in infants. J. Neurosurg. 23 (1965), 584--587. 23. New, P. F.J., Scott, W.R., Computed tomography of the brain and orbit. pp. 296--297. Baltimore: Williams and Wilkins. 1975.
224
H . H . Kaufman et al.: CT Scanning After Drainage of Haematoma
24. Parkinson, D., Chochinov, H., Subdural hematoma--some observations on their postoperative course. J. Neurosurg. 17 (1960), 901--904. 25. Rand, R.O., Ward, A.A., Jr., White, L.E., Jr., The use of the twist drill to evaluate head trauma. J. Neurosurg. 25 (1966), 410--415. 26. Robinson, R. G., The treatment of subacute and chronic subdural haematomas. Brit. Med. J. 1 (1955), 21--22. 27. Scotti, G., Terbrugge, K., McLacon, D., Belager, G., Evaluation of the age of subdural hematomas by computerized tomography. J. Neurosurg. 47 (1977), 311--315. 28. Shulman, K., Ranshohoff, J., Subdural hematoma in children. J. Neurosurg. 18 (1961), 175--181. 29. Smyth, H. S., Livingston, K.E., Ventricular infusion in the operative management of subdural hematoma. In: Current Controversies in Neurosurgery, pp. 566--571 (Morley, T. P., ed.). Philadelphia: Saunders. 1976. 30. So, S.C., Chronic subdural haematoma in the eldery. Aust. N.Z.J. Surg. 46 (1976), 166--169. 31. Stehbens, W.E., Pathology of the cerebral blood vessels, pp. 232--251. St. Louis: C. V. Mosby Co. 1972. 32. Svien, J. J., Gelety, J. E., On the surgical management of encapsulated subdural hematoma. J. Neurosurg. 21 (1964), 172--177. 33. Taarnhoj, P., Chronic subdural hematoma. Cleve. Clin. Q. 22 (1955), 150--156. 34. Tabbador, K., Shulman, K., Definitive treatment of chronic subdural hematoma by twist-drill craniostomy and closed system drainage. J. Neurosurg. 46 (1977), 220--226. 35. Trotter, W., Chronic subdural haemorrhage of traumatic origin, and its relation to pachymeningitis haemorrhagica interna. Brit. J. Surg. 2 (1914), 271--291. 36. Yashon, D., Jane, J. A., White, R. J., Sugar, O., Traumatic subdural hematoma of infancy. Arch. Neurol. 18 (1968), 370--377. Authors' address : H. Kaufman, M.D., Division of Neurosurgery, The University of Texas Medical School at Houston, Houston, TX 77030, U.S.A.
