Microsurgical treatment of spontaneous and non-spontaneous spinal epidural haematomas: neurological outcome in relation to aetiology.

BACKGROUND: This retrospective study evaluated the neurological outcome of 26 patients with spontaneous and non-spontaneous spinal epidural haematoma (SEH) who underwent microsurgical clot removal. It was the objective of the present study to investigate whether the aetiology of the SEH has an influence on the neurological outcome. METHODS: The medical records and radiological investigations of 26 patients with SEH were re-examined, and the latency between symptom onset and operation, and the size of the haematoma were determined. Motor and sensory function had been evaluated before surgery and 90 days after discharge. FINDINGS: Fourteen patients with non-spontaneous SEH and 12 patients with spontaneous SEH were identified. After surgery, neurological deficits improved in 9 of the patients with spontaneous (75%) and in 13 of the patients with non-spontaneous SEH (93%). In cases of spontaneous SEH, the median latency between symptom onset and operation was longer (72 hrs vs 7 hrs) and the median extent of the haematoma was larger (3.5 vs 2 spinal segments), than in the non-spontaneous cases. INTERPRETATION: Neurological outcome seems to be related to the aetiology of the SEH. Better outcome was observed in patients with surgically treated non-spontaneous SEH. Two explanations for this finding are worth considering. First, patients with non-spontaneous SEH usually are already under medical surveillance and can undergo medullary decompression more rapidly. Second, the compression of the spinal cord is possibly less severe in non-spontaneous SEH because of their smaller size

Spinal subdural and epidural haematomas: diagnostic and therapeutic aspects in acute and subacute cases.

BACKGROUND: The diagnosis of spontaneous spinal haematomas mainly depends on magnetic resonance imaging. This study evaluates the MRI characteristics of spinal epidural and subdural haematomas. The results were correlated with medical history, coagulation abnormalities and therapeutic outcome to provide guidelines for early diagnosis and treatment of spinal epidural and subdural hematomas. SUMMARY OF BACKGROUND DATA: Imaging signs of epidural and subdural haematomas have been reported before, however without special attention to the differential-diagnostic and therapeutic implications of haematoma localisation. METHOD: Seven patients (3 women, 4 men, age range 55-86 years) with acute progressive neurological deficits and without a history of severe trauma were studied. In all cases neurological examinations were performed after admission followed by MRI studies with T2 and T1 weighted images, before and after administration of contrast agent. Spinal angiography was performed twice to exclude a vascular malformation. All patients underwent open surgery. FINDINGS: Acute and subacute hematomas were detected once in the cervical spine, in five cases in the thoracic region and once in the lumbar region. The hematomas had an epidural location in three cases and a subdural in four. In the thoracic region subdural haemorrhage was much more common than epidural hematomas. Subdural blood collections were mainly found ventral to the spinal cord. Epidural haemorrhage was always located dorsal to the spinal cord. The evaluation of the haematoma localisation may be difficult occasionally, but delineation of the dura is frequently possible in good quality MRI. The clue to the diagnosis of ventrally located subdural haemorrhage is the absence of the "curtain sign", which is typical for epidural tumours. INTERPRETATION: Spontaneous spinal hematomas are frequently located in the thoracic spine. Subdural spinal haemorrhage is more frequent than epidural. Epidural haemorrhage is frequently located dorsal to the spinal cord because of the tight fixation of the dura to the vertebral bodies

Virtual pointer projection of the central sulcus to the outside of the skull using frameless neuronavigation -- accuracy and applications.

BACKGROUND:The purpose of this prospective study was to localize the central sulcus by frameless neuronavigation and to project this anatomical structure to the outside of the skull on the skin. This method was analyzed in respect to its practicability, accuracy, and potential applications. METHOD: In 27 patients investigated (28 unaffected hemispheres), the central sulcus was virtually projected to the outside of the skull using frameless neuronavigation and a virtual pointer elongation of 15 or 20 mm. The following parameters were measured on the scalp: 1. the distance between the bregma and the midline junction of the central sulcus, and 2. the angle between the central sulcus and the midline. These dada were compared with measurements based on the original axial MR images of these patients. Finally, a laboratory phantom study was designed in analogy to a patient's examination for estimation of the overall accuracy of the neuronavigation system in the experimental setup used in this study. FINDINGS: Virtual pointer projection of the central sulcus to the outside of the skull using frameless neuronavigation was found to be easily possible. The distance between the bregma and the midline junction of the central sulcus amounted to a mean of 55 mm on the left and 56 mm on the right. The angle between the central sulcus and the midline reached a mean of 63 degrees on the left and 60 degrees on the right. These data confirmed results of other studies with no frameless neuronavigation devices. The phantom study revealed a mean overall inaccuracy of 0.9 mm at a virtual pointer elongation of 15 mm. At a virtual pointer elongation of 20 mm, the mean overall inaccuracy of our study was 1.1 mm. These results correspond to the inaccuracy of frame based stereotaxy. INTERPRETATION: It is easily possible, valid, and reliable to virtually project the central sulcus to the outside of the skull with an acceptably low inaccuracy using frameless neuronavigation. This is important for research studies that correlate and integrate different functional imaging methods with the aid of frameless neuronavigation

Is the head position during preoperative image data acquisition essential for the accuracy of navigated brain tumor surgery?

OBJECTIVE: To analyze the influence of head positioning during preoperative image data acquisition on intraoperative accuracy of modern neuronavigation systems. MATERIAL AND METHODS: All measurements were performed preoperatively before opening the head. In 24 patients, preoperative MR image data acquisition was performed twice on a 0.5 T scanner using a contrast-enhanced T1-weighted sequence; first in the neutral head position, and thereafter in the surgical head position for pterional craniotomy. For both data sets, the Sylvian fissure, the central sulcus, and the superior and inferior temporal sulci were depicted on the patient's scalp using the frameless neuronavigation system EasyGuide Neurotrade mark. At the beginning of surgery, with the head fixed in a Mayfield clamp and an articulated instrument holder being used for fixation of the navigation system's pointer, the distances of 10 correlating points of the sulci for the two data sets were measured. To evaluate the accuracy of the navigation system in this experimental set-up, a phantom study was also performed. RESULTS: The phantom study revealed a mean inaccuracy of 1.6 mm (range 0.1-2.3 mm, standard deviation 0.6 mm). The patient study revealed a mean inaccuracy of 1.8 mm (range 0.4-2.8 mm, standard deviation 0.5 mm). CONCLUSIONS: The data suggest that the positioning of the patient's head during preoperative imaging plays no relevant role in intraoperative accuracy of neuronavigation. However, further studies and a larger number of patients with various pathologies in different regions of the brain are necessary to obtain a better understanding of the problem of brain shift in neuronavigation due to patient positioning alone, and to avoid procedure-related operative morbidity