27
Volume 68 November 1975
713
Section of Pafdiatrics President Dermod McCarthy MD
Meeting 4 April 1975
Advances in Pediatric Surgery [Abridged] Mr Kenneth Till (The Hospitalfor Sick Children, Great Ormond Street, London WCJN3JH)
Computerized Axial Tomography in Pmediatric Neurology and Neurosurgery The special advantages of computerized axial tomography in neuroradiological diagnosis when applied to pmediatric neurology and neurosurgery have rapidly become apparent. The EMI brain scanner is the only commercially available device with which computerized axial tomography can be carried out. The gently immobilized head is scanned by an extremely narrow beam of X-rays and the energy of the emerging ray is measured and recorded. After successive scanning at each of 180 degrees the total informition is computerized to reveal the tissue density at different points of a cross-section (or 'slice') of the head. The RB tissue densities may be printed out automatically but for convenience are usually displayed on an oscillograph; the display is then photographed on Polaroid film. Apart from the need to keep the head still for 3-4 minutes at a time there is no preparation or disturbance of the patient, who may indeed not require admission to hospital. The procedure is, therefore, particularly suited to children since hospitalization, injections and anesthesia are not essential. In many conditions encountered in paediatric neurology, such as epilepsy, migraine or suspected intracranial tumour, the clinical findings are insufficient for the p2ediatrician or neurologist to be confident that more elaborate neuroradiological studies are justified. An EMI scan (which is obtained with a radiation dosage similar to that of one lateral Fign1aEMiscansfolh ownmghead temporal skull radiograph) is a reliable investigation which hwmatoma. (By courtesy of DrJAmbrose, Atkinson allows the disclosure of such disorders as intra- Morley's -- .-., - Hospital, London')
injury.fAsteft
28
714 Proc. roy. Soc. Med. Volume 68 November 1975
Fig 2 Case 1 Cerebral abscess. Scan shows right temporal ring ofhigh density abscess capsule containing pus with low density surrounding edema
cranial tumour, hydrocephalus, subdural effusion and atrophic or degenerative diseases at a stage when symptoms or signs are very indefinite. When surgical intervention is required, it is no longer unusual for the neurosurgeon to proceed to operation without requiring other neuroradiological studies. Children who have sustained head injury are particularly difficult to treat without considerable anxiety because even the most careful clinical observation may not reveal a progressive and dangerous hematoma until it is almost too late to help. Cerebral angiography aided by echoencephalography has previously been the stand-by in these circumstances. The EMI scanner can now, without the delay and risk entailed by contrast studies in an ill child, resolve the problem within a few minutes (Fig 1). Because the radiation dosage is so small, it is possible to study such conditions as hydrocephalus after treatment or tumour response to radiotherapy, by repeating the scan at frequent intervals. Even more important is the detection of tumour recurrence in a child with vague or minimal symptoms which are sufficient to cause concern on the part of the parents or the doctor. The EMI scan reveals the density pattern of the tissues so that in many cases a diagnosis of the pathology can be made. Cystic fluid, fat, calcification (often insufficient to appear on conventional radiographs) and cerebral oedema are all recognizable. A few examples will illustrate these points.
Case 1 A 7-year-old boy had suffered headache for the past twelve days. Lumbar puncture had proved the presence of meningitis due to a Gram-negative bacillus and antibiotic treatment had relieved this symptom completely. Headache and vomiting then returned and the boy developed papilleedema. Within an hour of transfer to the neurosurgical department at The Hospital for Sick Children, an EMI scan was performed which showed a multilocular collection of fluid in the right temporal lobe with a dense vascular capsule. It was then possible to treat this cerebral abscess without delay (Fig 2). Case 2 A 9-year-old boy had suffered from headache and vomiting for the past three weeks with diplopia for one week. He had papillcedema and internal strabismus but no other neurological abnormality. Plain radiographs of the skull showed some decalcification of the sella turcica but were otherwise normal. EMI scan (Fig 3) revealed a well-defined mass of variable density in the left frontal region without cystic cavity and surrounded by aedema. At craniotomy an invasive neoplasm was found which surprisingly proved to be a neuroblastoma. Only partial excision was achieved because the mass invaded the caudate nucleus but postradiotherapy progress will be assessed by repeated EMI scans. Case 3 A 6-month-old baby was admitted for investigation of rapid head growth, the circumference being above the 97th centile. No developmental or other abnormality was found. Lumbar pneumoencephalography did not show the expected hydrocephalus but instead bilateral subdural effusions. These were treated by repeated aspirations and appeared to clear completely. Non-accidental injury was suspected but no evidence was found for this until readmission three months later with a tense fontanelle and drowsiness. EMI scan showed a recurrence of bilateral subdural effusions with a high density zone in the right temporal
Fig 3 Case 2 Left front neoplasm. Scan shows large mass extending to right of mid-line with cedema or cystic cavity in left frontal lobe
29
Fig 4 Case 3 Subdural effusion. Scan shows bilateral compression of brain in frontal region with dense area on right side suggesting recent haimatomaformation with enlarged ventricular system (atrophy or hydrocephalus) region suggestive of recent hemorrhage (Fig 4). At the same time the ventricular size was found to have increased when compared with previous scans and the sylvian fissures were dilated. The scan therefore not only confirmed the recurrence of the original condition but indicated that cerebral atrophy was developing and that recent hemorrhage had occurred. The scan was therefore of immediate assistance in diagnosis, provided help towards a prognosis (cerebral atrophy) and considerably influenced the total management of the problem (repeated non-accidental injury). Case 4 A 4-year-old boy had been treated in another country for two months for presumed tuberculous meningitis, the organism not having been identified. He had continued to lose weight and had begun vomiting when plain radiographs of the skull showed suture separation. A scan (Fig 5) shows the enlarged ventricular system and grossly dilated insular cisterns suggesting both obstructive hydrocephalus and cerebral atrophy. In addition the midline posterior fossa cyst shows the dense capsule with low density pus within. The advantages of diagnosis without other intervention and of monitoring during subsequent treatment are obvious in this case of cerebellar tuberculoma. Case 5 A 5-year-old girl had complained of upper cervical pain for five months of increasing frequency, with vomiting for three weeks. She was alert, cooperative with very mild papillcedema, and slight left limb ataxia. Plain skull radiographs showed suture separation and EMI scan revealed slight hydrocephalus of the Jateral and third ventricles with displacement of the fourth ventricle to the right. A large noncystic tumour in the posterior fossa was thus demonstrated and surgical intervention was undertaken without other investigations. A well-differentiated astrocytoma was totally removed.
Section ofPAwdiatrics
715
Fig 5 Case 4 Cerebellar tuberculoma. Scan shows dilated ventricular system, enlarged insular cisterns and cyst in posteriorfossa Case 6 A 13-year-old boy was admitted with the complaint of mild headache for the past nine days and occasional vomiting. When aged 12 weeks he had been treated for hydrocephalus with ventriculo-attial shunt, revision of this shunt being required at age 18 months. He had then developed normally with above average intelligence. He soon learnt to overcome his headache by pumping his own valve. An EMI scan showed a surprisingly gross degree of ventricular dilatation, the third ventricle being 2.5 cm in width. It was thus evident that the boy had made satisfactory progress in spite of an unobserved progressive hydrocephalus which had presumably accompanied an increasingly resistant shunt. The need for revision of the functioning shunt was at once apparent (Fig 6).
Fig 6 Case 6 Hydrocephalus. Scan shows gross ventricular dilatation
716 Proc. roy. Soc. Med. Volume 68 November 1975 The examples will it is hoped make it evident to paediatricians that computerized axial tomography will greatly improve our understanding and management of a wide variety of intracranial disorders, thanks principally to the simplicity of the investigation so far as the child is concerned and the very small radiation dosage.
Acknowledgment: I acknowledge with gratitude the generosity of Dr James Bull and his colleagues in the Department of Radiology at the National Hospital, Queen Square. It is through the use of the EMI scanner in that department that we have been able to acquire the experience of its particular usefulness in pediatric neurosurgery and neurology.
Mr Christopher Lincoln (Brompton Hospital, Fulham Road, London SW3 6HP)
Totally Corrective Cardiac Surgery in the First Two Years of Life The technique of profound hypothermia, limited cardiopulmonary bypass, and circulatory arrest
30
complex forms of congenital heart disease to be successfully repaired. Technique
While the infant is being anesthetized and pressure-monitoring lines are being placed, surface cooling is carried out by means of ice packs around the body. When the nasopharyngeal temperature has reached 28°C the ice packs are removed and the operation is started. By this time the heart rate has slowed to 80 or less per minute and the heart is not irritable when manipulated. Why it does not go into ventricular fibrillation at these temperatures or lower is obscure since in the early history of cardiac surgery, this regularly occurred in adults when surface cooling was used. Cardiopulmonary bypass is then instituted by means of an aortic cannula for arterial return, and a single cannula in the right atrium for the collection of venous blood to be returned to the machine. A membrane oxygenator is used in circuit. These oxygenators have the advantage of having no blood gas interface, and are as nearly physiological as can be presently engineered. The perfusate temperature is kept 12°C lower than the nasopharyngeal temperature. After about ten minutes of cardiopulmonary bypass 15°C is reached, and the circulation arrested. After a few minutes the heart becomes relaxed and bloodless, presenting an ideal operating field. An arbitrary figure has evolved of sixty minutes of safe circulatory arrest (with no obvious signs of neurological damage) in which intracardiac surgery can be performed. The atrial cannula is then replaced, cardiopulmonary bypass is reinstituted, and the heart and body are rapidly re-warmed to 34°C. Heart action quickly recovers, and bypass is discontinued. Further rewarming is carried out by placing the infant on a waterblanket (Fig 1>.
has allowed a realistic approach to the concept of one-stage total correction of complex congenital heart defects in infants and young children (Hikasa et al. 1967). Previous attempts at such early correction with conventional cardiopulmonary bypass techniques had an unacceptable mortality and morbidity. Palliative operations, for example banding of the pulmonary artery in infants with large ventricular septal defects, systemic-pulmonary artery shunts for tetralogy of Fallot, and atrial septectomy for the palliation of transposition of the Continue warming patient great arteries, are in themselves not without Anaesthetize on water-blanket Place monitoring lines mortality and morbidity. In addition, they in- Surface cool fluence the final corrective surgery. If, therefore, Decannul ate 280C i the one-stage corrective procedure can be carried Heart heart rate slow out with an equal or lower mortality than the Heart easy to handle combined figures for the two-stage correction, t aorta 0~~t Re-warm to 34 C the social, economic, psychological and surgical Cannulate and right atrium advantages are obvious. In 1950 Bigelow et al. demonstrated that the Perfusion + Perfusion 10 min 10 min duration* of total circulatory arrest compatible with survival was inversely proportional to Recommence 150C temperature. perfusion Stop circulation The recent introduction of surface-induced hypothermia to temperatures below 26°C, fol% INTRACARDIAC SURGERY 60 MINUTES lowed by a short period of cardiopulmonary bypass to 15°C, followed by circulatory arrest Fig 1 Cardiac surgery in infancy. Surface-induced for sixty minutes, has allowed many of the more hypothermia - limited cardiopulmonary bypass
Volume 68 November 1975
713
Section of Pafdiatrics President Dermod McCarthy MD
Meeting 4 April 1975
Advances in Pediatric Surgery [Abridged] Mr Kenneth Till (The Hospitalfor Sick Children, Great Ormond Street, London WCJN3JH)
Computerized Axial Tomography in Pmediatric Neurology and Neurosurgery The special advantages of computerized axial tomography in neuroradiological diagnosis when applied to pmediatric neurology and neurosurgery have rapidly become apparent. The EMI brain scanner is the only commercially available device with which computerized axial tomography can be carried out. The gently immobilized head is scanned by an extremely narrow beam of X-rays and the energy of the emerging ray is measured and recorded. After successive scanning at each of 180 degrees the total informition is computerized to reveal the tissue density at different points of a cross-section (or 'slice') of the head. The RB tissue densities may be printed out automatically but for convenience are usually displayed on an oscillograph; the display is then photographed on Polaroid film. Apart from the need to keep the head still for 3-4 minutes at a time there is no preparation or disturbance of the patient, who may indeed not require admission to hospital. The procedure is, therefore, particularly suited to children since hospitalization, injections and anesthesia are not essential. In many conditions encountered in paediatric neurology, such as epilepsy, migraine or suspected intracranial tumour, the clinical findings are insufficient for the p2ediatrician or neurologist to be confident that more elaborate neuroradiological studies are justified. An EMI scan (which is obtained with a radiation dosage similar to that of one lateral Fign1aEMiscansfolh ownmghead temporal skull radiograph) is a reliable investigation which hwmatoma. (By courtesy of DrJAmbrose, Atkinson allows the disclosure of such disorders as intra- Morley's -- .-., - Hospital, London')
injury.fAsteft
28
714 Proc. roy. Soc. Med. Volume 68 November 1975
Fig 2 Case 1 Cerebral abscess. Scan shows right temporal ring ofhigh density abscess capsule containing pus with low density surrounding edema
cranial tumour, hydrocephalus, subdural effusion and atrophic or degenerative diseases at a stage when symptoms or signs are very indefinite. When surgical intervention is required, it is no longer unusual for the neurosurgeon to proceed to operation without requiring other neuroradiological studies. Children who have sustained head injury are particularly difficult to treat without considerable anxiety because even the most careful clinical observation may not reveal a progressive and dangerous hematoma until it is almost too late to help. Cerebral angiography aided by echoencephalography has previously been the stand-by in these circumstances. The EMI scanner can now, without the delay and risk entailed by contrast studies in an ill child, resolve the problem within a few minutes (Fig 1). Because the radiation dosage is so small, it is possible to study such conditions as hydrocephalus after treatment or tumour response to radiotherapy, by repeating the scan at frequent intervals. Even more important is the detection of tumour recurrence in a child with vague or minimal symptoms which are sufficient to cause concern on the part of the parents or the doctor. The EMI scan reveals the density pattern of the tissues so that in many cases a diagnosis of the pathology can be made. Cystic fluid, fat, calcification (often insufficient to appear on conventional radiographs) and cerebral oedema are all recognizable. A few examples will illustrate these points.
Case 1 A 7-year-old boy had suffered headache for the past twelve days. Lumbar puncture had proved the presence of meningitis due to a Gram-negative bacillus and antibiotic treatment had relieved this symptom completely. Headache and vomiting then returned and the boy developed papilleedema. Within an hour of transfer to the neurosurgical department at The Hospital for Sick Children, an EMI scan was performed which showed a multilocular collection of fluid in the right temporal lobe with a dense vascular capsule. It was then possible to treat this cerebral abscess without delay (Fig 2). Case 2 A 9-year-old boy had suffered from headache and vomiting for the past three weeks with diplopia for one week. He had papillcedema and internal strabismus but no other neurological abnormality. Plain radiographs of the skull showed some decalcification of the sella turcica but were otherwise normal. EMI scan (Fig 3) revealed a well-defined mass of variable density in the left frontal region without cystic cavity and surrounded by aedema. At craniotomy an invasive neoplasm was found which surprisingly proved to be a neuroblastoma. Only partial excision was achieved because the mass invaded the caudate nucleus but postradiotherapy progress will be assessed by repeated EMI scans. Case 3 A 6-month-old baby was admitted for investigation of rapid head growth, the circumference being above the 97th centile. No developmental or other abnormality was found. Lumbar pneumoencephalography did not show the expected hydrocephalus but instead bilateral subdural effusions. These were treated by repeated aspirations and appeared to clear completely. Non-accidental injury was suspected but no evidence was found for this until readmission three months later with a tense fontanelle and drowsiness. EMI scan showed a recurrence of bilateral subdural effusions with a high density zone in the right temporal
Fig 3 Case 2 Left front neoplasm. Scan shows large mass extending to right of mid-line with cedema or cystic cavity in left frontal lobe
29
Fig 4 Case 3 Subdural effusion. Scan shows bilateral compression of brain in frontal region with dense area on right side suggesting recent haimatomaformation with enlarged ventricular system (atrophy or hydrocephalus) region suggestive of recent hemorrhage (Fig 4). At the same time the ventricular size was found to have increased when compared with previous scans and the sylvian fissures were dilated. The scan therefore not only confirmed the recurrence of the original condition but indicated that cerebral atrophy was developing and that recent hemorrhage had occurred. The scan was therefore of immediate assistance in diagnosis, provided help towards a prognosis (cerebral atrophy) and considerably influenced the total management of the problem (repeated non-accidental injury). Case 4 A 4-year-old boy had been treated in another country for two months for presumed tuberculous meningitis, the organism not having been identified. He had continued to lose weight and had begun vomiting when plain radiographs of the skull showed suture separation. A scan (Fig 5) shows the enlarged ventricular system and grossly dilated insular cisterns suggesting both obstructive hydrocephalus and cerebral atrophy. In addition the midline posterior fossa cyst shows the dense capsule with low density pus within. The advantages of diagnosis without other intervention and of monitoring during subsequent treatment are obvious in this case of cerebellar tuberculoma. Case 5 A 5-year-old girl had complained of upper cervical pain for five months of increasing frequency, with vomiting for three weeks. She was alert, cooperative with very mild papillcedema, and slight left limb ataxia. Plain skull radiographs showed suture separation and EMI scan revealed slight hydrocephalus of the Jateral and third ventricles with displacement of the fourth ventricle to the right. A large noncystic tumour in the posterior fossa was thus demonstrated and surgical intervention was undertaken without other investigations. A well-differentiated astrocytoma was totally removed.
Section ofPAwdiatrics
715
Fig 5 Case 4 Cerebellar tuberculoma. Scan shows dilated ventricular system, enlarged insular cisterns and cyst in posteriorfossa Case 6 A 13-year-old boy was admitted with the complaint of mild headache for the past nine days and occasional vomiting. When aged 12 weeks he had been treated for hydrocephalus with ventriculo-attial shunt, revision of this shunt being required at age 18 months. He had then developed normally with above average intelligence. He soon learnt to overcome his headache by pumping his own valve. An EMI scan showed a surprisingly gross degree of ventricular dilatation, the third ventricle being 2.5 cm in width. It was thus evident that the boy had made satisfactory progress in spite of an unobserved progressive hydrocephalus which had presumably accompanied an increasingly resistant shunt. The need for revision of the functioning shunt was at once apparent (Fig 6).
Fig 6 Case 6 Hydrocephalus. Scan shows gross ventricular dilatation
716 Proc. roy. Soc. Med. Volume 68 November 1975 The examples will it is hoped make it evident to paediatricians that computerized axial tomography will greatly improve our understanding and management of a wide variety of intracranial disorders, thanks principally to the simplicity of the investigation so far as the child is concerned and the very small radiation dosage.
Acknowledgment: I acknowledge with gratitude the generosity of Dr James Bull and his colleagues in the Department of Radiology at the National Hospital, Queen Square. It is through the use of the EMI scanner in that department that we have been able to acquire the experience of its particular usefulness in pediatric neurosurgery and neurology.
Mr Christopher Lincoln (Brompton Hospital, Fulham Road, London SW3 6HP)
Totally Corrective Cardiac Surgery in the First Two Years of Life The technique of profound hypothermia, limited cardiopulmonary bypass, and circulatory arrest
30
complex forms of congenital heart disease to be successfully repaired. Technique
While the infant is being anesthetized and pressure-monitoring lines are being placed, surface cooling is carried out by means of ice packs around the body. When the nasopharyngeal temperature has reached 28°C the ice packs are removed and the operation is started. By this time the heart rate has slowed to 80 or less per minute and the heart is not irritable when manipulated. Why it does not go into ventricular fibrillation at these temperatures or lower is obscure since in the early history of cardiac surgery, this regularly occurred in adults when surface cooling was used. Cardiopulmonary bypass is then instituted by means of an aortic cannula for arterial return, and a single cannula in the right atrium for the collection of venous blood to be returned to the machine. A membrane oxygenator is used in circuit. These oxygenators have the advantage of having no blood gas interface, and are as nearly physiological as can be presently engineered. The perfusate temperature is kept 12°C lower than the nasopharyngeal temperature. After about ten minutes of cardiopulmonary bypass 15°C is reached, and the circulation arrested. After a few minutes the heart becomes relaxed and bloodless, presenting an ideal operating field. An arbitrary figure has evolved of sixty minutes of safe circulatory arrest (with no obvious signs of neurological damage) in which intracardiac surgery can be performed. The atrial cannula is then replaced, cardiopulmonary bypass is reinstituted, and the heart and body are rapidly re-warmed to 34°C. Heart action quickly recovers, and bypass is discontinued. Further rewarming is carried out by placing the infant on a waterblanket (Fig 1>.
has allowed a realistic approach to the concept of one-stage total correction of complex congenital heart defects in infants and young children (Hikasa et al. 1967). Previous attempts at such early correction with conventional cardiopulmonary bypass techniques had an unacceptable mortality and morbidity. Palliative operations, for example banding of the pulmonary artery in infants with large ventricular septal defects, systemic-pulmonary artery shunts for tetralogy of Fallot, and atrial septectomy for the palliation of transposition of the Continue warming patient great arteries, are in themselves not without Anaesthetize on water-blanket Place monitoring lines mortality and morbidity. In addition, they in- Surface cool fluence the final corrective surgery. If, therefore, Decannul ate 280C i the one-stage corrective procedure can be carried Heart heart rate slow out with an equal or lower mortality than the Heart easy to handle combined figures for the two-stage correction, t aorta 0~~t Re-warm to 34 C the social, economic, psychological and surgical Cannulate and right atrium advantages are obvious. In 1950 Bigelow et al. demonstrated that the Perfusion + Perfusion 10 min 10 min duration* of total circulatory arrest compatible with survival was inversely proportional to Recommence 150C temperature. perfusion Stop circulation The recent introduction of surface-induced hypothermia to temperatures below 26°C, fol% INTRACARDIAC SURGERY 60 MINUTES lowed by a short period of cardiopulmonary bypass to 15°C, followed by circulatory arrest Fig 1 Cardiac surgery in infancy. Surface-induced for sixty minutes, has allowed many of the more hypothermia - limited cardiopulmonary bypass
