Biomedical subjects
Publications and source records attributed to M L Levy.
Birth injury has been defined as any condition that adversely affects the fetus during labor or delivery. This article discusses neonatal injury that results in a condition that requires neurosurgical management. The majority of these conditions result from a primary mechanical injury to the central or peripheral nervous system.
OBJECTIVE AND IMPORTANCE: Vertebrobasilar insufficiency resulting from disease of the subclavian artery is well recognized. Usually, this occurs as the "subclavian steal" syndrome in the context of chronic subclavian stenosis and is consequently well tolerated because of collateralization. Acute disruption of the hemodynamics of the aortic arch vessels, however, can produce disastrous sequelae. CLINICAL PRESENTATION: We present three cases of iatrogenic vertebrobasilar insufficiency sustained as complications of surgery of the left subclavian artery or its distal continuation. The cases were chosen from a review of approximately 400 emergency neurosurgery consultations requested at the Los Angeles County Hospital between November 1995 and February 1996. INTERVENTION: The first patient underwent repair of a traumatic brachial artery occlusion and awoke postoperatively with bilateral cortical blindness, right hemiparesis, and multiple cranial nerve deficits that were most likely caused by acute subclavian steal. The second underwent removal of a subclavian embolus and developed bilateral cerebellar infarction leading to persistent coma, possibly from inadvertent embolization of the vertebral artery during surgery. The third underwent resection and bypass grafting of a subclavian aneurysm. Good backflow was reported when the vertebral artery was disarticulated from the subclavian artery, and this vessel was not reimplanted into the graft. The patient suffered massive cerebellar infarction leading rapidly to brain death. CONCLUSION: There are myriad ways in which the inherent redundancy of the vertebrobasilar system may be jeopardized, and when this protective mechanism fails, the results can be disastrous. Flow through the vertebral arteries may be compromised by thrombosis, embolization, dissection, inappropriate ligation, excessive head rotation, hypotension, vasospasm, or acute subclavian steal. These examples illustrate the importance of understanding the complex physiology of posterior fossa circulation as the basis of pre-, intra-, and postoperative management of patients undergoing surgery of the subclavian artery.
In the management and evaluation of several of these birthmarks, it is advantageous, if not imperative, to apply a multidisciplinary approach. The patients benefit most from a cooperative team of physicians, often including the pediatrician, dermatologist, plastic surgeon, radiologist, and pathologist. Because of the often extensive presentation of many of these lesions, such an approach is extremely useful in planning their evaluation and management.
Complete extirpation of tumor remains the primary goal of neurosurgeons in treating intracranial craniopharyngiomas. The intimate relationship of these lesions with the structures of the skull base and the difficulties of obtaining adequate operative visualization often make total removal an elusive goal. The authors describe the use of a combined fronto-orbitozygomatic temporopolar craniotomy to maximize the operative corridor and thereby increase the probability of maximum tumor resection without morbidity and mortality. They applied this approach in four children with craniopharyngiomas that involved the sellar and parasellar, third ventricle, cavernous sinus, and interpeduncular fossa regions. The surgical results are summarized with a presentation of pre- and postoperative imaging from two illustrative cases. A detailed description of the operative procedure is provided with a comparison to other previously described surgical approaches.
Schöpf-Schulz-Passarge syndrome is a rare form of ectodermal dysplasia comprising hypotrichosis, hypodontia, unusual eyelid cysts, palmar-plantar keratosis, and nail dystrophy. To date, ten cases have been reported; all except one are compatible with autosomal recessive inheritance. We report on a family in which three full sibs and one half-sib have Schopf-Schulz-Passarge syndrome, yet there is no other evidence of dominant transmission in prior or subsequent generations. Possible explanations are discussed.
The risk of focal infarction secondary to the induced reversible arrest of local arterial flow during microsurgical dissection of middle cerebral artery (MCA) aneurysms was evaluated further to define the optimal approach to temporary arterial occlusion. To compare the effectiveness of brain-protection anesthetics, a group of patients treated with the intravenous agents, propofol, etomidate, and pentobarbital, administered individually or in combination, was compared to a group treated with the inhalational agent isoflurane. Forty-nine consecutive MCA aneurysm surgeries involving the temporary clipping of the parent vessel were retrospectively reviewed. Thirty-eight patients received intravenous brain-protection (IVBP) anesthesia. Groups of patients with and without infarctions, and receiving and not receiving IVBP, were compared based on the duration and nature of temporary arterial occlusion. Postoperative radiographic evidence of new infarction was used as the threshold for failure of occlusion tolerance. The overall infarction rate was 22.4% (11 of 49 patients), including 15.8% (six of 38 patients) in the IVBP group versus 45.5% (five of 11 patients) in the isoflurane (ISO) group. In the ISO group, the mean duration of temporary occlusion was 3.9 +/- 2.2 minutes for patients without infarction versus 12.2 +/- 4.3 minutes for patients with focal infarction (p < 0.01). In contrast, the mean duration was 13.6 +/- 10.6 minutes for patients without infarction and 18.5 +/- 9.9 minutes for patients with infarction in the IVBP group. All patients in the ISO group who underwent occlusion lasting 10 minutes or longer suffered an infarction versus five of 23 patients in the IVBP group. Patients with multiple aneurysms were found to be at increased risk of developing focal infarction, whereas those treated with intermittent temporary clip application were at a decreased risk. It is concluded that patients in whom focal iatrogenic ischemia is induced during MCA aneurysm clip ligation have a significant advantage compared with those receiving ISO when they are given pentobarbital as the primary neuroprotective agent or when they receive propofol or etomidate titrated to achieve electroencephalographic burst suppression, particularly if more than 10 minutes of occlusion time is required. It is also concluded that 10 minutes is a general guideline for safe, temporary occlusion of the MCA. The use of intermittent temporary arterial occlusion and patients with multiple aneurysms need further evaluation before specific recommendations can be made.
BACKGROUND: The term aplasia cutis is used to describe congenital localized defects of the skin. This affliction is the end result of various in utero events. Aplasia cutis of the face, although rare, has been associated with numerous dysmorphic features and described under many clinical terms. OBSERVATIONS: We studied 10 patients with oval, atrophic patches distributed in a linear pattern on the preauricular region of the face. Most of the defects were bilateral, and all consistently fell in an oblique line extending from the preauricular region to the angle of the mouth. This line corresponds to the region of fusion between the maxillary and mandibular facial prominences during embryonic development. CONCLUSIONS: This type of facial aplasia cutis may be the result of incomplete fusion of the ectodermal groove between the maxillary and mandibular facial prominences. Although other types of facial skin defects may share a similar pathogenic mechanism, they are distinct in that they occur in different regions and may have other abnormal facial features.
As proximal nerves are relatively spared in length-dependent, axonal polyneuropathy, we theorized that a sural/radial amplitude ratio (SRAR) might be a sensitive indicator of mild polyneuropathy. In this study, sural amplitudes and SRARs in patients with signs of mild axonal polyneuropathy were compared to those of normal, age-matched control subjects. Sural and radial sensory responses were measured in a standard fashion in all subjects. Thirty polyneuropathy patients had an average SRAR of 0.29 as compared to 0.71 for the 30 normal subjects. An SRAR of less than 0.40 was a strong predictor of axonal polyneuropathy, with 90% sensitivity and 90% specificity, as compared to an absolute sural amplitude of less than 6.0 microV, which had sensitivity of only 66%. Additionally, unlike the sural amplitude, the ratio did not vary significantly with age. We conclude that the SRAR is a sensitive, specific, age-independent electrodiagnostic test for mild axonal polyneuropathy.
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OBJECTIVE: Endoscopes have been used adjunctively for spinal and cranial microsurgical procedures and directly for ventricular exploration, fenestration, and catheterization. Technological advances now allow for multi-imaging technologies, including a so-called "heads-up display," allowing the surgeon to view the operative field and the endoscopic image simultaneously. INSTRUMENTATION: A high-resolution, active matrix liquid crystal display is built into the frame of the eyewear, with a display density of 182,000 pixels (280 x 650 pixels) and a resolution of 200 lines. The display occupies approximately 20% of the visual field. The headgear weighs 4 oz, with dimensions of 9 x 18 x 17 cm. The modular interface weighs 7 oz. Two different visualization systems can be used. The first uses a single integrated interface (IM 300), whereas the second (remote 900) is a 900-MHz frequency modulation wireless system that provides for a line-of-sight link between the NTSC source and the modular interface (range = 100 ft). RESULTS: Heads-up adjunctive endoscopy was used in 60 patients during 18 months. The procedures included 16 craniotomies, 1 intradural lumbar biopsy, and 42 ventriculoperitoneal shunt placements. Follow-up was obtained at a minimum of 1 year. Patient age ranged from 1 month to 58 years. The only complication was a transient loss of auditory evoked potentials after contact of the eighth nerve by the endoscope. CONCLUSION: We describe a portable, light-weight heads-up display imaging system, which we have used in 60 operative procedures. Benefits of the heads-up system include portability and a high-resolution digital monocular image, which reduces eye strain and vertigo. The ideal headgear will likely be an extremely high-resolution liquid crystal display-based or cathode ray tube-based semi-immersive system, with all of the benefits currently described for two-dimensional heads-up systems (i.e., light weight, portability, image quality, and the avoidance of complications associated with immersive systems).
OBJECTIVE: The benefit of aggressive management and surgical intervention in preterm infants with massive Grade IV intracranial hemorrhage has been questioned based on the poor outcome of this group of patients despite such therapy. To further delineate this problem, we reviewed the records of premature neonates in this category as to outcome and initial hospital cost. METHODS: We performed a retrospective review of the medical records at our institution from 1977 to 1987 to identify premature neonates who had sustained massive hemorrhagic infarction of one hemisphere in addition to having blood in both ventricles and progressive hydrocephalus. RESULTS: During the study, a total of 52 such patients were identified, only 19 (6 female and 13 male patients) of whom survived. Intellectual function was observed to be greater than 2 standard deviations below the mean in 15 of the 19 patients, between 1 and 2 standard deviations below the mean in 1 of 19, and 1 standard deviation below the mean in 3 of 19. Motor function was as follows: 12 of 19 had marked spastic quadriparesis, 2 of 19 had moderate spastic quadriparesis, 3 of 19 had spastic hemiplegia, 1 of 19 had spastic diplegia, and 1 of 19 had mild spastic hemiparesis. Eleven of 19 had chronic seizure disorders. The first hospitalization cost for the group of patients exceeded, on the average, $150,000 per patient for the 19 long-term survivors. CONCLUSION: As we have previously reported, logistic regression analysis determined that grade of hemorrhage was the only significant predictor of cognitive and motor outcomes. Most premature neonates with massive intracranial hemorrhages do not survive. The outcomes in those who do is very poor and the cost so high that we suggest that until therapeutic intervention exhibits efficacy, the consideration of withdrawal of life support should be presented as an option to the parents of these unfortunate children.
OBJECTIVE AND IMPORTANCE: We report a case of two separate cervicothoracic, extradural leiomyomas occurring in a male pediatric patient with acquired immunodeficiency syndrome (AIDS). To our knowledge, such a case has never been reported in the literature. CLINICAL PRESENTATION: A 9-year-old male patient with AIDS presented with progressive leg weakness. At examination, he was myelopathic with paraparesis and a T4 sensory level to pinprick. A magnetic resonance image revealed two separate cervicothoracic lesions causing cord compression. INTERVENTION: The patient underwent resection of both lesions. Postoperatively, he regained normal strength in his legs and was discharged home after 2 weeks. CONCLUSION: With the ever-growing number of pediatric patients with AIDS, the entity will likely be encountered with increasing frequency in the future. Because of the potential for neurological recovery and cure, the neurosurgeon should be cognizant of this entity.
OBJECTIVE: An analysis of 76 preterm infants with Grade III or IV intracranial hemorrhage and surgically treated progressive hydrocephalus was undertaken to determine mortality, intellectual impairment, and motor deficit. METHODS: The variables examined were degree of prematurity, birth weight, sex, Apgar scores, extent of intracranial hemorrhage, seizures, age at time of initial placement of a ventricular catheter reservoir to control hydrocephalus, need to convert the reservoir to a ventriculoperitoneal shunt, timing of the conversion of the reservoir to a ventriculoperitoneal shunt, and number of shunt revisions. Outcome was assessed for statistical significance using hierarchical linear regression and logistic regression analyses. RESULTS: Linear regression analysis determined that mortality was best predicted, in order of importance, by extent of intracranial hemorrhage, number of shunt revisions, and birth weight (P < 0.0001, R = 0.79). Grade of hemorrhage, weight at birth, and presence of seizure activity were the most important determinants of motor outcome (P < 0.001, R = -0.78). CONCLUSIONS: Logistic regression analysis of the 41 long-term survivors determined that grade of hemorrhage was the most important variable in determining cognitive outcome (P < 0.0001), motor function (P < 0.0001), and presence of seizure activity (P < 0.001). A logistic model of survival determined that grade of hemorrhage and multiple shunt revisions (more than five) were the most important determinants (P < 0.0001) of survival. In conclusion, the overwhelming factor in determining outcome in this patient group was the extent of intracranial hemorrhage.
Advances in video technology have enabled the incorporation of high-resolution electronic imaging of an operative field during microneurosurgical and endoscopic procedures. While current video-based monoscopic camera and monitor systems produce an excellent image, the third dimension is lacking and the operative field and image are at different locations. We describe a head-mounted display (HMD) that allows the surgical team to simultaneously visualize a surgical field and a high-resolution magnified stereoscopic image which includes a picture-in-picture capability. Stereoscopic HMDs should result in improved efficiency and safety in both endoscopic and open microsurgical procedures. Additional uses relate to surgical training and operative rehearsals.
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Thirty-six cases of pilocytic astrocytomas treated at the Childrens Hospital of Los Angeles from 1984 through 1995 were reviewed. The mean age at initial presentation was 8 years (range 15 months to 14 years). These patients were followed for an average of 5.5 years. No patient was given chemotherapy or radiation therapy after the initial surgery for pilocytic astrocytoma. Twenty-three patients (64%) had a gross total resection with no residual tumor on immediate postoperative imaging studies. Three of these children had tumor recurrences 2-5 years after their initial surgery, requiring re-excision of their tumors. All 3 patients are subsequently tumor-free, with follow-up ranging from 4 to 10 years. In 4 patients with residual tumor involving the brainstem, there has been neither imaging evidence of tumor enlargement nor progression of clinical findings at 2.5, 4, 6 and 6 years, respectively. Nine of the 13 patients with residual tumor underwent re-excision, either for progression of symptoms or documented tumor growth on imaging studies. The second operation was undertaken an average of 1 year (range 1 month to 6 years) after the first. In 4 of these children (11% of our whole series), the recurrent tumor was classified as anaplastic astrocytoma. Three of these 4 children received radiation and/or chemotherapy, with only 1 patient showing disease progression in the follow-up period. Repeat blinded histopathological examination of these tumors confirmed both diagnoses. However, it was noted that 3 of the 4 pilocytic astrocytomas which subsequently showed anaplastic change initially displayed increased perivascular cellularity, while only 2 of the remaining 32 tumors exhibited this feature. These results encourage continued vigilance in the follow-up of pilocytic astrocytomas, and describe a histological feature which might indicate a more aggressive disease course.