Emile A. M. Beuls

The Currarino triad: neurosurgical considerations.

OBJECTIVES:The Currarino triad, a relatively uncommon hereditary disorder, is often associated with tethered cord and anterior myelomeningocele. Little is known of the implications of these neuroanatomic malformations or of the neurosurgical attitude. The objective of this study is to identify the spinal cord and meningeal malformations associated with the Currarino triad and to discuss the risks and benefits of surgical intervention. METHODS:We analyzed the spinal cord malformations and the neurosurgical involvement with the Currarino triad by retrospective chart review. RESULTS:The Currarino triad neuroanatomic malformations were identified in five patients. The Currarino triad was associated with a tethered cord in three patients, a myelomeningocele in five patients, a syrinx in two patients, a fistula between the colon and spinal canal in two patients, and an Arnold-Chiari Type 1 malformation in one patient. CONCLUSION:Full spine imaging is required for all patients diagnosed with the Currarino triad. Magnetic resonance imaging of the head should be performed in every patient with neuroanatomic anomalies. Surgery of an anterior myelomeningocele is not necessarily indicated, only in the rare case in which the space-occupying aspect is expected to cause constipation or problems during pregnancy or delivery. Constipation directly after birth is seen in virtually all patients with the triad. Therefore, constipation cannot be used to diagnose a tethered cord syndrome nor indicate tethered cord release. Fistulas between the spinal canal and colon have to be operated on directly.

Thoracic disc herniation and acute myelopathy: clinical presentation, neuroimaging findings, surgical considerations, and outcome.

OBJECT Thoracic disc herniations (TDHs) may occasionally present with an acute myelopathy, defined as a variable degree of motor, sensory, and sphincter disturbances developing in less than 24 hours, and resulting in a Frankel Grade C or worse. Confronted with such a patient, the surgeon has to decide whether to perform an emergency operation and whether to use an anterior or posterior approach. The authors analyze their own experience and the pertinent literature, focusing on clinical presentation, imaging findings, surgical timing, technique, and outcome. METHODS Among 250 patients who underwent surgery for symptomatic TDH, 209 had at least 1 year of follow-up at the time of writing, including 8 patients who presented with an acute myelopathy. They were surgically treated using standard thoracoscopic microdiscectomy, careful blood pressure monitoring, and intravenous methylprednisolone. The authors analyzed pre- and postoperative neuroimaging, and Frankel scores preoperatively, at discharge, and 1 year postoperatively. RESULTS Although 5 patients had multiple TDHs, the symptomatic TDH was invariably situated between T9-10 and T11-12. Seven TDHs were giant, 6 were calcified, 6 were accompanied by myelomalacia, and 4 were accompanied by segmental stenosis. Although sudden dorsalgia was the initial symptom in 6, a precipitating event was noted in only 1. All patients had severe neurological deficits by the time they underwent surgery. Frankel grades improved from B to D in 2 patients, from C to E in 4, and from C to D and B to E in 1 patient each. All patients regained continence and ambulation. Transient complications were CSF leak (in 2 patients), and intraoperative blood loss greater than 1000 ml, reversible ischemic neurological deficit, and subileus (in 1 patient each). CONCLUSIONS Approximately 4% of TDHs present with an acute myelopathy. They are often situated between T9-10 and T11-12, large or giant, and even calcified. They almost invariably cause important cord compression (sometimes aggravated by an associated segmental stenosis) and myelomalacia. Their clinical presentation may be misleading, and diagnosis may be delayed until other causes (especially vascular) have been excluded and the clinical picture has become more complete. Interestingly, whereas a precipitating event or trauma is rarely present, dorsalgia frequently precedes profound myelopathy and may help to make an early diagnosis. Remarkable recovery is possible even with profound neurological deficit, a delay of several days, in the elderly, and in the presence of myelomalacia, provided the spinal cord is adequately decompressed and intraoperative hypotension is strictly avoided. Although alternative approaches more familiar to most neurosurgeons may be used, the anterior transthoracic approach has the advantage of reaching the TDH in front of the compromised spinal cord, avoiding any manipulation. In experienced hands, thoracoscopic microdiscectomy combines the advantage and versatility of an anterior approach with minimal postoperative discomfort. The authors conclude that TDH-related acute myelopathy may have a favorable outcome when managed correctly, and they strongly recommend that every single patient should undergo surgical treatment.

Intraspinal dermoid and epidermoid tumors: report of 18 cases and reappraisal of the literature.

Intraspinal dermoid and epidermoid tumors are two histopathological subtypes of cutaneous inclusion tumors of the spine. This classification is based on obsolete embryological knowledge. In fact, according to current embryology, both tumor types consist of ectodermal derivatives. Therefore, we hypothesized that dermoid and epidermoid tumors do not differ in clinical practice. To explore this hypothesis, we studied the clinical, radiological and intraoperative findings of 18 patients, and related these findings to the histopathological characteristics of the tumor. No differences were found between dermoid and epidermoid tumors regarding clinical presentation, radiological examination and outcome, while intraoperative diagnosis by the surgeon correlated with the histopathological diagnosis in only 8 of 18 cases. Therefore, the histopathological difference between intraspinal dermoid and epidermoid tumors is not important in clinical practice and should be avoided. A new nomenclature is proposed in which both tumor types are referred to as ‘spinal cutaneous inclusion tumors’.

Short-and long-term limbic abnormalities after experimental febrile seizures

Experimental febrile seizures (FS) are known to promote hyperexcitability of the limbic system and increase the risk for eventual temporal lobe epilepsy (TLE). Early markers of accompanying microstructural and metabolic changes may be provided by in vivo serial MRI. FS were induced in 9-day old rats by hyperthermia. Quantitative multimodal MRI was applied 24 h and 8 weeks later, in rats with FS and age-matched controls, and comprised hippocampal volumetry and proton spectroscopy, and cerebral T2 relaxometry and diffusion tensor imaging (DTI). At 9 weeks histology was performed. Hippocampal T2 relaxation time elevations appeared to be transient. DTI abnormalities detected in the amygdala persisted up to 8 weeks. Hippocampal volumes were not affected. Histology showed increased fiber density and anisotropy in the hippocampus, and reduced neuronal surface area in the amygdala. Quantitative serial MRI is able to detect transient, and most importantly, long-term FS-induced changes that reflect microstructural alterations.

The microanatomical environment of the subthalamic nucleus

High-frequency stimulation of the subthalamic nucleus (STN) is a widely performed method to treat advanced Parkinson disease. Due to the limitations of current imaging techniques, the 3D microanatomy of the STN and its surrounding structures in the mesencephalon are not well known. Using images they obtained using a 9.4-tesla magnetic resonance (MR) imaging unit, the authors developed a 3D reconstruction of the STN and its immediate surroundings. During the postmortem investigation of a human brain, a sample of tissue in the area around the STN was isolated. This brain tissue was scanned in the three orthogonal planes at 1-mm slice thickness. The images generated were compared with photographs of conventionally stained brain tissue slices in different neuroanatomical books, and a 3D reconstruction was made. High-field MR imaging is an appropriate method for visualizing the microanatomy of the STN and its surroundings. The images allow an optimal analysis of the microenvironment of the STN in the three orthogonal planes and can be used for 3D reconstructions of this area with possible clinical applications in the future.

Long-term behavioral outcome after early-life hyperthermia-induced seizures

Febrile seizures (FS) are among the most common types of seizures in the developing brain. It has been suggested that FS cause cognitive deficits that proceed into adulthood, but the information is conflicting. The aim of the present study was to determine whether experimental FS have long-term cognitive or behavioral deficits. FS were induced by hyperthermia (30 minutes, approximately 41 degrees C) in 10-day-old rat pups, and behavioral testing was performed. Hippocampus-dependent water maze learning, locomotor activity, and choice reaction time parameters (e.g., reaction time) were generally not affected by FS. However, more detailed analysis revealed that reaction times on the right side were slower than those on the left in controls, whereas this was not observed after FS. Early-life experimental FS did not cause overt cognitive and behavioral deficits, which is in line with previous work, but eliminated the lateralization effect in reaction time known to occur in normal controls, an effect that may be due to the combination of FS and kainic acid or to FS alone.

Two brothers with a symptomatic thoracic disc herniation at T11-T12: clinical report

BackgroundIn contrast to what is commonly believed, thoracic disc herniations are not rare lesions. Their etiopathogenesis is largely unknown, but may be linked to trauma, Scheuermann’s disease or a degenerative back.ObjectiveWe report two brothers with a symptomatic thoracic disc herniation at T11–T12 and address the possibility of a genetic factor as well as other factors in the etiopathogenesis of (symptomatic) thoracic disc herniations.Clinical featuresBoth brothers were in their early thirties and had a physically demanding job, however, only the first one was a smoker and was diagnosed with Scheuermann’s disease.ConclusionThe etiology of thoracic disc herniations is likely multifactorial. Their occurrence in siblings may reflect some genetic predisposition or may be merely coincidental, given the high prevalence of thoracic disc herniations in asymptomatic individuals. Further research, including genetic studies, is warranted.

Correlation of postmortem 9.4 tesla magnetic resonance imaging and immunohistopathology of the human thoracic spinal cord 7 months after traumatic cervical spine injury.

OBJECTIVE:To correlate high-resolution magnetic resonance imaging (MRI) with immunohistopathology in the injured human spinal cord. METHODS:Postmortem MRI scans at a field strength of 9.4 T, as well as standard histology and immunohistochemistry, were performed on an excised specimen of human high thoracic spinal cord, obtained 7 months after the initial trauma, several segments below a severe spinal cord lesion (C5). RESULTS:A precise correlation is described between MRI and immunohistochemistry of the long white matter tracts undergoing Wallerian degeneration and of an extension of the cervical lesion into the high thoracic cord. CONCLUSION:MRI, the only imaging technique that currently provides useful information on the spinal cord parenchyma after trauma, is rapidly evolving. High-field scanners of up to 9.4 T are being clinically tested. The present postmortem investigation of an isolated spinal cord specimen demonstrates the precise correlation that can be achieved between imaging and pathology. In future investigations, this type of technique can lead to a more precise description of spinal cord injuries and their consequences in remote tissue. Translation into the clinical setting will improve diagnosis and follow-up of spinal cord injured patients.

The Arnold-Chiari type II malformation at midgestation.

The Arnold-Chiari malformation type II (ACMII) is reported to be reversible after closure of a myelomeningocele at midgestation. To elucidate the developmental state of the ACMII malformation at the approximate time fetal surgery is performed, the ACMII of a 20-week human fetus was investigated in vitro using high-field magnetic resonance microscopy at 9.4 T and compared with the hindbrain of a neurologically intact fetus of the same gestational age. Up to 20 weeks of gestation, the developmental failures caused by the early embryonic herniation of the posterior fossa contents are the dominant feature of fetal ACMII, but after 20 weeks, the accelerated and disproportionate growth of the cerebellum dominates. As midgestational surgery stops the leakage of cerebrospinal fluid, the posterior fossa will expand in time to allow further normal growth of both the cerebellum and brain stem. Some early developmental anomalies already present in the primitive rhombencephalon due to early embryonic hindbrain herniation as well as some intra-axial anomalies are probably not reversible.

Clinical characteristics and surgical outcome in 25 cases of childhood tight filum syndrome

OBJECTIVE Tight filum syndrome (TFS) is caused by a thick (abnormal T1 MRI), shortened (low-lying conus), or non-elastic filum (strictly normal MRI). We carefully analyzed children treated for suspect TFS with or without radiological abnormalities. METHODS Twenty-five children, operated between 2002 and 2009, were retrospectively identified. All children had been evaluated by a multidisciplinary team preoperatively. Symptoms, signs and diagnostic test results were categorized (neurologic, urologic, orthopedic, dermatologic) and compared pre- and one year postoperatively. Normal MR was defined as conus medullaris (CM) at or above mid-body L2 and filum diameter less than 2 mm. Occult TFS (OTFS) was defined as TFS with normal MR. RESULTS DEMOGRAPHICS 17 girls, 8 boys, age 2-18 years, including 11 syndromal children. CLINICAL PRESENTATION all children had problems in the neurologic category and at least one other category: urologic (n = 17), orthopedic (n = 21), and dermatologic (n = 11). MR findings: low-lying CM (n = 14) including 2 with thick filum, normal CM but fatty filum (n = 2), strictly normal (n = 9). Clinical outcome one year postoperatively: neurologic 20 improved, 5 stabilized; urologic 13 improved, 3 stabilized, 1 worsened; orthopedic (8 children presenting with scoliosis) 3 improved, 4 stabilized, 1 worsened. All children with OTFS (n = 9) improved in at least one and 8 improved in all affected categories. CONCLUSIONS Children with strong clinical suspicion for TFS (≥ 2 affected categories) with or without abnormal MR findings will likely benefit from surgery. In such cases we suggest a detailed full spine MR, a multidisciplinary diagnostic work-up, and eventual untethering through an interlaminar microsurgical approach.