Biomedical subjects

Michael L Levy

Publications and source records attributed to Michael L Levy.

At least 19 recordsLinked to original sources

PubMed2006

Emotional and psychological impact of delayed craniosynostosis repair.

INTRODUCTION: Among children with craniosynostosis, there exists an interesting dynamic involving parents' preconceptions of craniosynostosis and its repair, influenced in large part by differing cultural perspectives. In a time in which we are understanding how critical a child's early formative years are in influencing his/her emotional and psychological development, the authors describe one medical aspect involved in that dynamic process. MATERIALS AND METHODS: The authors reviewed their cumulative experience at the Children's Hospital San Diego between January 2000 and June 2004 and identified nine children with significant craniofacial deformities and, for one reason or another, had delayed surgical repair. DISCUSSION: The authors have found that by age 6, parents will often bring their children back to their physician and insist on surgical correction. The significant motivating factor in most of these cases stems from teasing by classmates with respect to head shape. In this manuscript, we report and discuss some of the emotional and psychological issues associated with delayed craniosynostosis repair. Often times, these issues are overlooked or underemphasized in the overall surgical care of such patients.

Adaptation, Psychological↗

PubMed2006

Endoscopic third ventriculostomy.

Among patients with idopathic aqueductal stenosis or impedance of cerebrospinal fluid (CSF) flow in the posterior fossa due to tumour, endoscopic fenestration of the floor of the third ventricle creates an alternative route for CSF flow to the subarachnoid space via the prepeduncular cistern. By reestablishing CSF flow, this procedure dissipates any pressure gradient on midline structures. This may obviate the need for traditional CSF shunt diversion techniques in such settings. Currently, endoscopic third ventriculostomy is indicated in approximately 25% of patients with hydrocephalus and can be performed instead of shunt placement. Appropriate patients are those with aqueductal stenosis (10%), obstructive tumours (10%), and obstructive cysts (5%). Additional recent data suggest the favorability of third ventriculostomy over shunt implantation in additional patient cohorts. Operative technique is discussed.

Humans↗

PubMed2006

Aneurysms in children: review of 15 years experience.

INTRODUCTION: Intracranial aneurysms in children are rare. The location, size, age, and presentation in the young are markedly different from that of adults. The 15-year experience of the senior author in southern California is presented. METHODS: All paediatric patients treated for cerebral aneurysm over a 15-year period were identified. Intraoperative and postoperative data were collected retrospectively from the medical records. The need for additional surgery as well as the incidence of complications including death, hemiparesis, seizures, memory disturbances, and the need for subsequent cerebrospinal fluid (CSF) diversion were identified. RESULTS: Fifty children were identified (54 lesions). Subarachnoid haemorrhage was the most common mode of presentation with the average Hunt-Hess grade being I-II. The locations of the lesions were middle cerebral (10), internal carotid (8), anterior communicating (7), posterior cerebral (6), posterior communicating (5), pericallosal (4), anterior cerebral (3), choroidal (3), posterior inferior cerebellar (3), basilar (2), vertebral (2) and frontopolar (1) arteries. Clinical vasospasm was encountered in eight of our patients, but no cases were observed in those younger than nine years. Long-term outcome was excellent in 22 cases, good in 20 and poor in nine, with one death and two patients lost to follow-up. CONCLUSION: Analysis of our data suggested a predilection for the posterior circulation compared to adults, larger size, more complex architecture, and a decreased incidence of clinical vasospasm in the younger age group. This series and a review of the literature suggest that aneurysmal disease in children may be distinct from that of adults.

Adolescent↗

PubMed2006

Indirect revascularisation for paediatric moyamoya disease: the EDAMS technique.

Moyamoya disease can have devastating effects on paediatric patients as a result of cerebral ischaemia. Several direct and indirect surgical methods have been devised in order to facilitate revascularisation. Debate has long ensued about which methods are most efficacious and yet safe. The authors describe their experience with a straightforward method for performing the EDAMS (encephalo-duro-arterio-myo-synangiosis) technique.

Carotid Arteries↗

PubMed2006

The pathophysiologic mechanism of cerebellar mutism.

OBJECTIVE: Cerebellar mutism (CM) is a postoperative complication of mainly pediatric posterior fossa surgery. Multiple theories exist for explaining this phenomenon. We have made an attempt to further understand this entity given a particularly interesting case as it relates to multiple pathophysiologic pathways. METHODS: We have reviewed the details surrounding a particularly interesting case of CM. A retrospective analysis of this patient's clinical history and recovery is described. An extensive literature review has been performed in conjunction with an attempt to help elucidate details and a better understanding of CM. RESULTS: A thorough analysis of existing theories as to the pathophysiologic mechanism of CM has been performed as it relates to the details of this particular case. A case is described in which a child exhibiting CM abruptly improved and made a relatively quick recovery after the triggering of the melodic speech pathway by way of watching and beginning to sing along with a video. It appears that this incident involving a familiar song catalyzed various speech pathways, which apparently were in some state of shock. This phenomenon seems to be a temporary entity involving not only the mechanical coordination of speech production, but also the initiation of speech itself. CONCLUSIONS: Evidence exists for a pathophysiologic pathway for speech by way of coordinating phonation and articulation. In addition, there seems to exist a pathway by which the initiation of speech may be altered or halted by posterior fossa pathology, namely, vermian or dentate nuclear injury. In particular to this case, we found that the incidental appreciation of other forms of speech, melodic in this instance, may be the key to help stimulate and accelerate the recovery from CM.

Acoustic Stimulation↗

PubMed2006

Robotic virtual endoscopy: development of a multidirectional rigid endoscope.

INTRODUCTION: The use of neuroendoscopy has increased in the past 20 years. Despite an increase in the number of indications for use, novel adjuncts and modifications to existing endoscopes remain all but nonexistent. We introduce a robotic virtual endoscope with applications for neurosurgery that could serve as a novel step in the evolution of future endoscopic technologies. METHODS: Over the past 8 years, we have worked on the construction of a prototype endoscope with three degrees of freedom that was designed to allow for enhanced safety while maximizing the benefits of virtual field rendition and robotic control. We have developed a prototype to examine a cerebral ventricular model in vitro that functions via either a direct video- or computer-based interface. RESULTS: Assessment of viewing angulation with robotic feedback has verified the accuracy of the prototype. Models support the ability of the endoscope to localize regions identified via a software interface. CONCLUSION: The endoscope is a rigid virtual robotic endoscope that provides complete visual coverage of a three-dimensional space by controlling an adjustable viewing direction with three degrees of freedom.

Endoscopes↗

PubMed2005

Complications of interhemispheric transcallosal approach in children: review of 15 years experience.

OBJECTIVE: The interhemispheric transcallosal approach to deep-seated lesions in and around the ventricular system avoids cortical manipulation and injury. Few case series discuss the morbidity associated with this approach. This study describes the 15-year experience of the senior author in Southern California. METHODS: All pediatric patients who have undergone interhemispheric, transcallosal resections of mass lesions over a 15-year period were identified. The surgical approach was uniform with respect to positioning of the patient. Intra-operative and post-operative data were collected retrospectively from the medical records. The need for bridging vein ligation as well as the incidence of hemiparesis, seizures, memory disturbances, and the need for subsequent cerebrospinal fluid (CSF) diversion were identified. RESULTS: Sixty-five patients were identified. The incidence of transient post-operative hemiparesis appeared to be higher in those patients who required ligation of one or two parasagittal veins (44.6% versus 18.5%) with no difference in long-term outcome. Nineteen percent (18.5%) of patients had post-operative seizures; however, no long-term seizure disorder was identified. Nine percent (9.2%) had reports of transient short-term memory deficits. Thirty-four percent (33.8%) of patients required secondary operative intervention for CSF diversion. The total complication rate, including need for CSF diversion, transient hemiparesis, infection, post-operative seizures, and memory disturbance was 36.9%. By 1 year, the total number of patients with persistent hemiparesis, memory disturbance, or seizures refractory to medication was 4 (6.2%). CONCLUSION: This series demonstrates that the interhemispheric transcallosal corridor is a versatile and safe approach in childhood, resulting in low post-operative permanent morbidity.

Adolescent↗

PubMed2005

Intradural cranial congenital dermal sinuses: diagnosis and management.

OBJECTIVE: The congenital dermal sinus (CDS) is a benign tumor-like entity that has unique anatomical and clinical features. We retrospectively examined our data to determine factors associated with adverse outcomes for cranial-based dermal sinuses. METHODS: We retrospectively examined our data obtained from patients presenting between 1975 and 2002. Sixty-seven patients with a CDS were found. Of these, 20 cases of a cranial CDS were identified, 15 of which had evidence of an intradural component. RESULTS: Surgical treatment of congenital dermal sinuses was accompanied with, in general, excellent results. Poor outcomes were most strongly associated with delays in diagnosis. The most common complications were infection at the surgical site (five patients) and hydrocephalus necessitating ventriculoperitoneal shunt placement (two patients). Permanent neurological deficits were rare. CONCLUSION: Cranial CDSs are unusual lesions found in children. A majority of these lesions may penetrate the dura and lead to significant complications if not promptly identified and treated in an appropriate and timely fashion.

Child↗

PubMed2005

Subfrontal transbasal approach and technique for resection of craniopharyngioma.

A multimodality approach to craniopharyngioma, including minimally invasive stereotactic techniques, microsurgery, conventional radiotherapy, and radiosurgery has been recommended to tackle craniopharyngioma aggressively while minimizing harm to the patient. With all approaches, there are varying levels of risk for endocrinological morbidity, vascular complications, neuropsychological and behavioral disorders, neurocognitive disorders, and learning disabilities. Although many treatment options are available, total tumor resection remains the most commonly performed procedure for treatment of craniopharyngioma, and it is still believed to give the patient the greatest chance of having an independent and productive life with low risk of recurrences. The authors prefer the subfrontal transbasal approach for resection of these tumors, and they describe this approach and illustrate it with the accompanying figures.

Brain Neoplasms↗

PubMed2005

Surgical correction of metopic synostosis.

BACKGROUND: Premature closure of the metopic suture results in deformation of the anterior portion of the calvarium, which can vary from mild to severe. In mild forms, there is only prominent ridging of the metopic suture; more severe forms result in a marked narrowing of the frontal and temporal regions that in turn affects the supraorbital rims and produces hypotelorism. METHODS: The authors retrospectively reviewed 39 consecutive cases of metopic synostosis treated over a 12-year period. RESULTS: The average age at referral was 5 months, with surgery performed at an average age of 7.5 months. Fifteen infants had other congenital anomalies, with eight having synostosis of other sutures. Follow-up ranged from 7 months to 6 years, with an average of 29 months. In three mild cases, burring of the metopic ridge was performed with excellent aesthetic results in all cases. The other 36 patients had significant deformity of the supraorbital ridges and temporal regions, with obvious hypotelorism for over 50% of the time. In these cases, the patients underwent craniofacial reconstruction to normalize their appearance. In addition, the lateral aspect of the sphenoid ridges, including the orbital roof and lateral orbital wall to the infraorbital fissure, was removed to free the cranial base. The average blood loss was under 400 ml and the average hospital stay was 3.6 days. Results were considered good to excellent in all except three cases, which had recurrence of a prominent metopic ridge; two required a second operation after 6 months for burring of this ridge, whereas the third was treated conservatively with an orthotic headband. CONCLUSION: Mild forms of metopic synostosis can be successfully treated with burring of the metopic ridge alone. Severe forms require craniofacial reconstruction and may be associated with other congenital abnormalities, additional synostosis, and developmental delay. In all cases, the operative procedure must be tailored to the nature and severity of the deformity.

Child↗

PubMed2005

Microsurgical keyhole middle fossa arachnoid cyst fenestration.

Microsurgical keyhole fenestration is a safe and effective surgical procedure for the treatment of middle fossa arachnoid cysts. This procedure can be performed with minimal morbidity through a keyhole craniotomy. Patient selection is crucial, as is knowledge of the surgical anatomy. We provide a detailed description of the technique, with Illustrations of the key aspects of the procedure.

Arachnoid Cysts↗

PubMed2005

Retinal hemorrhage and pediatric brain injury: etiology and review of the literature.

Retinal hemorrhages have long been linked with child abuse and, in particular, the "shaken baby/shaking-impact" syndrome. However, the presence of retinal hemorrhages is neither necessary nor sufficient for the diagnosis of child abuse. Additionally, retinal hemorrhages are also associated with an ever-expanding list of conditions, each of which carries important implications for patients and their families. To correctly interpret a patient's retinal hemorrhages, the physician requires a broad knowledge base, including of child abuse, the "shaken baby/shaking-impact" syndrome, the differential diagnosis of retinal hemorrhages and the types of retinal hemorrhage and their diagnostic implications. We review the literature regarding types of retinal hemorrhage and their associated etiologies.

Accidents, Traffic↗

PubMed2005

Gunshot wounds to the spine in adolescents.

OBJECTIVE: The incidence of spinal instability after penetrating gunshot wounds to the spine in adolescents is unknown. We describe our experience over a 15-year period. METHODS: Hospital records were reviewed retrospectively. After injury and emergency care, patients were transferred to a rehabilitation facility. Examinations were completed using the American Spinal Injury Association and Frankel scales on admission, discharge, and 6 and 12 months after injury. Severity of injury was described by: 1) degree of neurological damage, 2) degree of preserved neurological function, and 3) presence of instability. RESULTS: Sixty patients were identified with a mean age 15.6 years (+/- 2.7 yr). Twelve patients had cervical, 31 thoracic, and 17 lumbosacral injuries. No operative treatments were used in their care. Thirty-four patients had complete neurological deficits. Mean acute hospitalization was 21.1 days (+/- 22.8 d), and mean rehabilitation stay was 86.3 days (+/- 48.9 d), for a total hospitalization of 107.4 days (+/- 65.9 d). At 1 year, 19 patients were ambulatory and 53 were autonomous. Despite the presence of bony involvement in all, no evidence of spinal instability was noted on follow-up dynamic imaging. Even in two patients with apparent two-column disruption, no instability was noted. At 1-year follow-up, significant (nonfunctional) improvement was noted in the neurological examination (P < 0.0001). Improvements were most notable in those patients with cervical injuries, followed by thoracic and lumbar injuries. CONCLUSION: After penetrating gunshot wounds to the spine, patients at 1-year follow-up examinations have evidence of significant, but nonfunctional, improvement. No evidence of spinal instability was noted in this study, and no surgical intervention was required.

Adolescent↗

PubMed2005

Gel-based surgical preparation resulting in an operating room fire during a neurosurgical procedure: case report.

Despite general reports of fires in the operating room, those during neurosurgical procedures are rare. The most significant contributor to perioperative fires is excess oxygenation. The consideration of novel gel-based surgical preparation solutions as potential fuel sources should be included in the literature. Given the significant patient risk and legal ramifications of surgical fires, education regarding operating room fires and the potential for prevention and treatment is requisite. The authors describe the case of an 18-month-old girl who, while undergoing a resection of a right retroauricular scalp mass, suffered partial thickness bums as a result of the ignition of surgical preparation solution following the use of monopolar electrocautery.

Administration, Topical↗

PubMed2004

Initial experience with antibiotic-impregnated silicone catheters for shunting of cerebrospinal fluid in children.

INTRODUCTION: Infection is a major complication of cerebrospinal fluid (CSF) shunting procedures. Recently, rifampin-impregnated and clindamycin-impregnated silicone catheters have been developed in an attempt to prevent and/or reduce the incidence of shunt infections. In vitro and in vivo animal studies have shown their efficacy in reducing bacterial colonization of catheters. However, these shunts are yet to be evaluated in clinical trials and their safety and efficacy in preventing shunt infections is unknown. METHODS: Between April 2002 and April 2003, 31 children (age range 6 months to 17 years, mean 4.5 years) underwent implantation of an antibiotic-impregnated silicone catheter for CSF diversion. All surgeries were performed by a single neurosurgeon (HSM) at a single medical center. The Codman Hakim Bactiseal silicone catheter was used in all children. Thirty-two catheters were implanted in 31 children. All children have been followed since surgery (for an average of 19 months). For comparison, the previous 46 standard implanted shunts over a similar period of time were reviewed (average follow-up 31 months). RESULTS: Of the 32 implanted catheters, 11 involved placement of a new complete shunt system, 8 were distal revisions, and 13 were proximal/ventricular revisions. There were fewer early and late complications than in the standard shunt group (12.5 and 18.8% vs. 23.9 and 34.8%). There was no local reaction from implantation of the catheters. One child contaminated his distal catheter by disrupting his abdominal incision. None of the other patients have developed any evidence of shunt infection to date. CONCLUSION: Rifampin-impregnated and clindamycin-impregnated silicone catheters appear to be safe and well tolerated in children. Preliminary results suggest a low incidence of shunt infection. Longer follow-up and a larger number of patients are needed to more accurately assess the efficacy of these catheters compared with traditional silicone catheters.

Adolescent↗

PubMed2004

Management of pilocytic astrocytoma with diffuse leptomeningeal spread: two cases and review of the literature.

INTRODUCTION: Leptomeningeal dissemination of juvenile pilocytic astrocytoma (JPA) is a rare event. We report two children with disseminated JPAs treated with a chemotherapeutic agent, temozolomide, after progression of the disease despite surgery, traditional chemotherapy, and/or radiation therapy. CASE REPORTS: Patient 1 presented with hydrocephalus and progressive lower extremity weakness, and was found to have a suprasellar mass as well as extensive spinal disease. Ventriculoperitoneal shunting, decompressive laminectomy with spinal tumor debulking, and chemotherapy with carboplatin and vincristine were initially employed. However, disease progressed and craniospinal irradiation and temozolomide were used. Patient 1 remains in a fair condition today, 2 years later. Patient 2 presented at 8 months of age with failure to thrive. Imaging revealed a cystic lesion in the hypothalamic region with extensive subarachnoid metastatic disease to the spine. Biopsy was performed followed by chemotherapy with vincristine, cyclohexylchloroethylnitrosourea (CCNU), 6-TG, and procarbazine. Due to the continued progression of the disease, cytoreductive surgery was performed and her chemotherapeutic regimen was switched to temozolomide. Two years after initial presentation patient 2 is clinically much improved with stable residual disease. DISCUSSION: We review the literature and discuss treatment strategies for this challenging disease.

Antineoplastic Agents, Alkylating↗

PubMed2004

Craniofacial reconstruction with a fast resorbing polymer: a 6- to 12-month clinical follow-up review.

OBJECT: Resorbable polymer implants have become a compelling option in the treatment of acquired and congenital craniofacial deformities. In particular, the resorbable polylactide and polyglycolide polymers have demonstrated excellent safety profiles in multiple in vitro, animal, and clinical studies and are currently being used in a wide variety of craniofacial applications. In pediatric craniofacial reconstruction a desirable attribute of fixation is early resorption, which may limit the duration of any effect on cranial growth. In this paper the authors discuss the biomaterial properties of a fast resorbing polymer (FRP) and the clinical results in a series of patients who participated in a 6- to 12-month study. METHODS: The authors performed craniofacial reconstruction by using FRP implants in 29 patients beginning in August 2002. All patients experienced maintenance of stable bone fixation followed by bone healing. Cosmetic results were rated satisfactory or excellent, except for one unsatisfactory cosmetic result caused by disease progression. CONCLUSIONS: Results of this study support the effectiveness of an FRP implant in a variety of craniofacial surgical procedures including craniosynostoses, fibrous dysplasia, cranial defects, and encephaloceles.

Absorbable Implants↗

PubMed2004

Fronto-orbital and cranial osteotomies with resorbable fixation using an endoscopic approach.

Over the past 3 years the authors have used modified minimally invasive endoscopic techniques in the surgical correction of craniosynostosis. For selected patients, these techniques offer an alternative to traditional techniques, minimizing postoperative morbidity and the need for cranial banding. Long-term follow-up will be needed to assess the ultimate efficacy of these techniques. Traditional techniques for repair of craniosynostosis have historically had a record of excellent aesthetic results with acceptable morbidity. Ultimately, each patient is best served by a customized plan, developed and implemented by a multidisciplinary team capable of the full range of techniques.

Absorbable Implants↗