Biomedical subjects
Publications and source records attributed to D D Cochrane.
In order to restore spinal integrity following posterior exposures of the spinal canal in children, we describe modifications of Raimondi's laminotomy technique. The use of a pneumatic dissecting tool with foot-plate to create a hinged osteoplastic laminotomy is described, as are techniques for securing the laminotomy flap in place at the end of the procedure.
The long-term functional outcome of 101 children born with meningomyelocele between 1971 and 1981 was assessed, by a combination of retrospective chart review and follow-up assessments. The children had been managed at birth using a process of nonstandardized selection. Eighty-three of the 101 patients survived after a minimum follow-up of 8.6 years, for a mortality rate of 18%. Forty-four of 83 children (53%) were community ambulators, and this correlated well with the presence of intact quadriceps function. Forty-eight children (58%) attended normal school and were grade-appropriate. Sixty-two of 83 patients (75%) were socially continent of urine, and 71/83 (86%) were socially continent of stool. Hydrocephalus was present in 93 of the 101 children in the study, and 85 children were shunted. Half of the shunted children required a shunt revision in the first year of life, and thereafter the rate of revision decreased, so that after 2 years the risk of revision was approximately 10% per year.
Selective functional posterior rhizotomy (SFPR) is a popular operation for the treatment of spasticity in children with cerebral palsy, but the physiologic basis of the procedure is poorly understood. As part of SFPR operations in 60 consecutive children, the responses to electrical stimulation of posterior lumbosacral roots and rootlets, and the corresponding anterior roots were studied. In addition, similar electrical stimulation of posterior roots was performed in four nonspastic "control" children. Sustained responses to 50 Hz stimulation, one of the criteria used to signify abnormality in the spastic children, was found frequently in the "control" children. Contralateral spread to the lower limb muscles and suprasegmental spread to the upper limbs, face, and neck were determined to be the most valid criteria which differentiated abnormal from normal responses. Stimulation of anterior nerve roots at 50 Hz caused sustained responses and ipsilateral lower limb spread, at a low threshold compared to that of corresponding posterior roots. The results of this study bring into question the validity of some of the criteria that are used to select abnormal posterior rootlets in the SFPR procedure, and suggest criteria that may be more valid based on findings in nonspastic children.
Fifty consecutive children are described with spastic cerebral palsy treated with selective functional lumbar and sacral rhizotomy and followed for a minimum of 6 months. In all patients, spasticity improved postoperatively, but this was not necessarily accompanied by a functional improvement. Eighteen children who could not walk preoperatively were able to do so after rhizotomy. All 17 children who could walk preoperatively could do so following surgery, and in 15, gait was improved. Complications included transient urinary dysfunction in 4 children and sensory loss in 1. The operative procedure evolved with time: the technique of replacement laminotomy was refined; the electrophysiologic basis for selection of nerve rootlets changed after studies of nonspastic controls; smaller percentages of the L3 and L4 roots were sectioned in an attempt to prevent postoperative weakness of quadriceps, and there was a trend in the most recent patients to cut a smaller portion of all the posterior roots.
The technique for freeing adherent ventricular catheters is described in which a Bugbee wire, insulated except for the tip, is used to deliver a monopolar coagulating current to the tissue adherent to the drainage holes of the catheter. This may have some advantage over the use of an uninsulated metal cannula for delivery of a unipolar diathermy cutting current. The technique described has permitted effective and safe removal of adherent ventricular catheters.
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Intramedullary spinal cord tumors are uncommon in children, and delayed diagnosis is common. Unlike the situation in adults, low-grade astrocytomas predominate followed by ependymomas and other gliomas. Recent technological advances, including MR imaging, intraoperative ultrasonography, the ultrasonic surgical aspirator, and the operative laser, have made radical resection of intramedullary tumors feasible. The long-term results of modern-day surgery using these techniques are only now becoming available, and the role of adjuvant radiotherapy or chemotherapy for the usual low-grade tumors remains unclear. The risk of spinal deformity after laminectomy in children and the effects of radiotherapy on the growing spine create special challenges in the treatment of pediatric intramedullary tumors.
Surgical educators are facing changes in residency training that have a direct impact on the opportunity that surgeons and residents have for clinical teaching and learning. The knowledge required of residents continues to escalate. Further, as resident positions are reduced, the opportunity for inter-resident education is decreased. Increased service-to-education ratios may result in resident discontent unless surgeons take an active role in the resident's educational experience. The purpose of this study was to examine the educational activities that occur during the operating-room experience. Technical training in the procedure being done was the primary educational activity, but there were long periods when no form of education was taking place. The operating room provides the teacher and learner with uninterrupted time together, and this time can and should be used for clinical teaching and learning.
Three children with congenital hydrocephalus are described in whom increased intracranial pressure was associated with severe, long-lasting cortical visual impairment. Following shunt revisions or reconstructive craniotomies, visual improvement began within hours. It is speculated that increased intracranial pressure can occasionally result in chronic hypoperfusion of the parietal-occipital lobes, either due to posterior cerebral artery compromise secondary to transtentorial pressure gradient or to direct compression of cerebral tissues.
Enhanced and non-enhanced computed tomography (CT) brain scans were performed within 72 h of surgery on 21 children in whom brain tumors had been resected totally or subtotally, and scans were repeated at varying intervals thereafter. Biopsies of the resection margins were performed in 12 patients at the end of the surgical procedure. The immediate CT scan showed enhancement in the resection margin in 13 of the 21 patients and in 9 of the 13, the enhancement disappeared on follow-up scans. There was discordance between the results of immediate CT scan examination and the biopsies of the resection margins in 7 of the 12 cases. The advantages and disadvantages of an immediate postoperative scan versus a more delayed CT scan are discussed.
Cerebral dysgenesis encompasses varied disorders of brain development. Based on the understanding of these conditions provided by histopathologists, embryologists, radiologists and developmental pediatricians, surgeons are able to appropriately assist in the care of these patients. The surgeon can offer assessment of the ventriculomegaly that commonly accompanies cerebral dysgenesis in addition to providing methods to control hydrocephalus, to reconstruct cranial and facial malformations and to remove dysfunctional tissue. For most patients, surgical intervention is only one of the many factors that determine developmental prognosis. Based on the foundation built by other specialists, this review discusses cerebral dysgenesis from the perspective of historical and current surgical interventions.
Between 4% and 8% of cases of spina bifida cystica occur in a cervical or cervicothoracic location. Despite a large body of literature concerning spinal dysraphism, there has been little written specifically about patients afflicted with this disorder in a cervical location. Eight children who presented at birth with posterior cervical or cervicothoracic lumps, all of which represented a dysraphic state, are discussed. Two types of abnormalities were noted. Three patients had hydromyelia with an associated myelocystocele herniating posteriorly into a meningocele sac. In these three patients there was an associated Chiari II malformation and hydrocephalus. The other five children had a meningocele in which a band of tissue extended from the posterior aspect of the spinal cord through a defect in the bone and fascia to the posterior part of the meningocele sac itself. No patient had a lesion that could be described as a meningomyelocele. The investigation and surgical management of these conditions are discussed and the need for intradural exploration to untether the spinal cord in the cervical region is stressed.
A modification of the technique combining sagittal strip, circular occipital and biparietal wedge craniectomies (Albright's procedure) for the treatment of sagittal synostosis, with prominent occipital bossing, is described. "Keyhole," as opposed to wedge, parietal craniectomies allow improvement in the shape of the skull, beginning intraoperatively, while eliminating the outbending of the parietal bone that occurs at the apex of a wedge craniectomy.
Spontaneous spinal extradural hematoma is an uncommon cause of cord compression and paraplegia. The clinical presentation of this entity is uniform, with sudden pain followed by sensory and motor dysfunction. Unlike other considerations in the differential diagnosis of cord compression, here the pain and clinical deficit may remit suddenly and spontaneously. This feature may obscure the diagnosis of an organic cause for cord dysfunction. This report describes a patient whose extradural hematoma was caused by hemorrhage from an arteriovenous malformation. Dramatic reduction of his pain and paralysis followed myelography.
A male child with type I (no neck) Klippel-Feil syndrome presented at birth with a transient and partial cord injury. Investigations failed to reveal spinal instability or foramen magnum compression. Subsequent deterioration led to investigations that demonstrated neuroschisis. A cervical meningocoele manque with cord tethering was found at exploration and untethering reversed the deficit. The surgical pathology of the cervical cord is described.
Apnea is a known complication of the Chiari II malformation presenting in infancy. Obstructive apnea secondary to bilateral abductor palsy or laryngomalacia and centrally mediated expiratory apnea with cyanosis can occur. Observations of 9 patients suggest that these forms of apnea may represent stages in a continuum of brain stem dysfunction due to the combined effects of the hindbrain malformation and its compression, hydrocephalus and progressive arachnoiditis. Obstructive apnea in some patients may be reversed by optimal control of hydrocephalus with or without cervical decompression. These patients may also develop episodes of cyanotic expiratory apnea of central origin (PEAC). This form of apnea does not respond to surgical or medical treatment and may show progressive worsening over time. Five of 6 patients with this form of apneic spell died suddenly, 2 of these died despite full recuscitative efforts. It is recommended that reports of treatment address results for both forms of apnea.
We describe a 15-month-old girl who presented with an acute hemiplegia. The sequence of events appears to have been clinically silent subarachnoid hemorrhage, vasospasm, infarction and a second lethal hemorrhage 3 months later. The old infarction was seen on computed tomography during her second illness. Autopsy confirmed the presence of a recent rupture of an intracranial aneurysm and old hemorrhage. In addition there was an unusual fibroblastic proliferation in the aneurysm wall. This case demonstrates that clinically silent subarachnoid hemorrhage, vasospasm and infarction can occur as complications of aneurysms, even in very young children.
All intracranial IV digital subtraction angiographic examinations performed over the past 2 years were reviewed retrospectively to ascertain the uses and limitations of this technique for the evaluation of pediatric intracranial disease. Of the various abnormalities studied, this imaging technique was particularly useful in diagnosing venous and dural sinus abnormalities; in screening for suspected large aneurysms, vascular malformations, and major arterial occlusive disease; and in preoperative vascular mapping. IV digital subtraction angiography has selected usefulness in confirming brain death, in evaluating cerebral ischemia, in identifying vascular abnormalities underlying intracranial hemorrhage, and in evaluating vascularity and sinus extension of masses. The IV route for digital subtraction angiography is not useful in diagnosing segmental arterial occlusive or small-vessel disease, nor is it useful in preoperative localization of specific arterial supply to arterial venous malformations, aneurysms, or neoplasms. IV digital subtraction angiography can be performed successfully in children of all ages with minimal patient morbidity. For most patients, the diagnostic information obtained was adequate without the need for standard cerebral arteriography.