A number of classification schemes for intracranial dural arteriovenous fistulas (AVFs) have been published that claim to predict which lesions will present in a benign or aggressive fashion based on radiological anatomy. We have tested the validity of two proposed classification schemes for the first time in a large single-institution study. A series of 102 intracranial dural AVFs in 98 patients assessed at a single institution was analyzed. All patients were classified according to two grading scales: the more descriptive schema of Cognard, et al. (Cognard) and that recently proposed by Borden, et al. (Borden). According to the Borden classification, 55 patients were Type I, 18 Type II, and 29 Type III. Using the Cognard classification, 40 patients were Type I, 15 Type IIA, eight Type IIB, 10 Type IIA+B, 13 Type III, 12 Type IV, and four Type V. Intracranial hemorrhage (ICH) or nonhemorrhagic neurological deficit was considered an aggressive presenting clinical feature. A total of 16 (16%) of 102 intracranial dural AVFs presented with hemorrhage. Eleven of these hemorrhages (69%) occurred in either anterior cranial fossa or tentorial lesions. When analyzed according to the Borden classification, none (0%) of 55 Type I intracranial dural AVFs, two (11%) of 18 Type II, and 14 (48%) of 29 Type III intracranial dural AVFs presented with hemorrhage (p < 0.0001). After exclusion of visual or cranial nerve deficits that were clearly related to cavernous sinus intracranial dural AVFs, nonhemorrhagic neurological deficits were a feature of presentation in one (2%) of 55 Type I, five (28%) of 18 Type II, and nine (31%) of 29 Type III patients (p < 0.0001). When combined, an aggressive clinical presentation (ICH or nonhemorrhagic neurological deficit) was seen most commonly in intracranial dural AVFs located in the tentorium (11 (79%) of 14) and the anterior cranial fossa (three (75%) of four), but this simply reflected the number of higher grade lesions in these locations. Aggressive clinical presentation strongly correlated with Borden types: one (2%) of 55 Type I, seven (39%) of 18 Type II, and 23 (79%) of 29 Type III patients (p < 0.0001). A similar correlation with aggressive presentation was seen with the Cognard classification: none (0%) of 40 Type I, one (7%) of 15 Type IIA, three (38%) of eight Type IIB, four (40%) of 10 Type IIA+B, nine (69%) of 13 Type III, 10 (83%) of 12 Type IV, and four (100%) of four Type V (p < 0.0001). No location is immune from harboring lesions capable of an aggressive presentation. Location itself only raises the index of suspicion for dangerous venous anatomy in some intracranial dural AVFs. The configuration of venous anatomy as reflected by both the Cognard and Borden classifications strongly predicts intracranial dural AVFs that will present with ICH or nonhemorrhagic neurological deficit.

The natural history of aggressive intracranial dural arteriovenous fistulae (ICDAVF) is unknown. Despite this, the recently proposed classification scheme of Borden et al (Borden*) has the potential to predict aggressive lesion behavior after presentation for any lesion, but has so far been untested. In addition, they discuss a new but logical treatment strategy for aggressive ICDAVF based on the elimination of retrograde leptomeningeal venous drainage (RLVD). Our similar philosophy and substantial experience with these lesions, provides a unique opportunity to test these hypotheses. A cohort of 46 Borden* grade II and III ICDAVF was selected from a series of 102 ICDAVF seen at a single institution between 1984 and 1995. Patients with these lesions, presumed to have an aggressive course were all offered treatment. Conservative therapy was chosen by 14 (30%) patients, 22 (47%) had surgery, and 20 (43%) had embolisation either as sole treatment or prior to surgery. During the follow-up period (249 lesion months) for the conservatively treated group, four (29%) patients died. Excluding presentation, these patients were observed to have interval rates of intracranial hemorrhage (ICH), non haemorrhagic neurological deficit (NHND), and mortality, of 19.2%, 10.9%, and 19.3% / lesion year respectively. The 11 patients who had embolisation alone were followed for a total of 344 months after treatment. All nine patients who had lesion obliteration, or subtotal obliteration with elimination of RLVD, as confirmed by angiography, experienced improvement or complete clinical recovery. Two patients had subtotal obliteration without elimination of RLVD. One died from interval ICH and the other experienced a delayed NHND. Twenty-five surgical operations were performed on 23 ICDAVF in 22 patients. Resection of the ICDAVF was performed in 9 patients, and 16 patients were treated with surgical disconnection alone. Complications occurred in 3/9 (33%) patients who had their lesions resected and none of the disconnected group. Failure to achieve angiographic obliteration of RLVD in 2 patients treated with resection was associated with an adverse outcome in both cases (death, and interval NHND). All 16 (100%) of the disconnected group were shown to have undergone angiographic obliteration with excellent clinical outcome. Untreated, Borden* grade II and III ICDAVF have a poor natural history. Also, persistence of RLVD after inadequate treatment results in adverse outcomes. Embolisation usually improves the safety of surgical access and may lead to obliteration on its own in some cases. For the aggressive ICDAVF, surgery is required in most cases, and our data confirm that surgical disconnection alone results in cure of all Borden* grade III ICDAVF, and in grade II lesions, if not cure, conversion to a benign grade I lesion.

Reliance on MR imaging alone may lead to misdiagnosis. As the osteoid osteoma may be difficult to identify and the MR features easily misinterpreted, optimisation of MR technique is crucial in reducing the risk of missing the diagnosis. Unexplained areas of bone marrow oedema in particular require further imaging (scintigraphy and CT) to exclude an osteoid osteoma.

The recently proposed classification scheme of Borden, Wu, and Shucart (Borden*) should have the ability to identify those intracranial dural arteriovenous fistulae (ICDAVF) which will continue to behave in a benign fashion. We examine for the first time the natural history of benign ICDAVF, including the predictive ability of this grading scale, and the implications for lesion management. A cohort of 55 Borden* grade I lesions was selected from a heterogeneous series of 102 consecutive ICDAVF seen at one institution between 1984 and 1995. Data were collected prospectively from 1991. Grade I lesions were those whose nidus drained directly into a dural venous sinus (DVS) or meningeal vein. The absence of retrograde leptomeningeal venous drainage (RLVD) was an important feature. Intracranial haemorrhage (ICH), non haemorrhagic neurological deficit (NHND), and death were considered aggressive features. There were 23 cavernous sinus, 2 foramen magnum, 1 middle cranial fossa, and 29 transverse sinus lesions. One patient received obliterative surgical treatment. Thirty-two lesions were observed only, and 22 patients developed symptoms or signs requiring palliative embolisation. Two minor complications occurred following embolisation: transient pulmonary aedema (1), and an asymptomatic pericallosal artery embolus (1). Follow-up was available on 48 (89%) patients for a total of 133 patient years (mean 33 months). This included 26 of the 32 patients observed and all 22 of the patients embolised. Aggressive interval behavior was seen in only one patient. Symptom improvement or resolution was observed in the majority of patients, whether observed only [21/26 (81%)], or whether they required embolisation for symptom palliation [19/22 (86%)]. Overall, 53 of the 54 (98%) of ICDAVF behaved in a benign fashion in the follow-up period. The predictable benign natural history of patients identified as Borden* grade I at presentation mandates a conservative approach to these ICDAVF. In some patients, when symptom severity demands, palliative embolisation is an effective and safe therapy.

Endoscopic transsphenoidal surgery for pituitary adenomas has been introduced as an alternative to transsphenoidal microsurgery. This is the first Australian study to evaluate a single surgeon's experience by comparing our results with other series and attempting to identify a learning curve. Retrospective analysis was carried out on 79 consecutively treated patients by fully endoscopic transsphenoidal surgery by a single neurosurgeon over a period spanning from July 1998 to September 2010 at St George Public and Private hospitals. The mean age at time of surgery was 56.7 years (SD ± 16.3, range 26-85) and the mean follow-up period was 38.2 months (SD ± 33, range 1-136). Gross total resection (GTR) was noted in 63% of patients, endocrinological cure was achieved in 53% and visual field improvements were noted in 86% of patients. Intra-operative CSF leaks occurred in 19% of procedures, while the rates of post-operative CSF rhinorrhea was 3% and post-operative diabetes insipidus was 13%. There was one post-operative death (1%). Compared to microsurgery, intra-operative CSF leaks and meningitis seem less frequent with an endoscopic approach. With increasing experience, we found a non-statistically significant trend towards higher rates of GTR, and improved visual fields. Endocrinological cure rates were clearly better with experience (p < 0.01). There may be a learning curve that can be overcome in 30-40 cases. Endoscopic transsphenoidal surgery provides similar tumour and patient outcomes when compared to transsphenoidal microsurgery. In this single surgeon's experience, there was a trend to indicate improved performance with more case experience.

Benign bone tumors are rare but are more common than primary malignant bone tumors. The early accurate diagnosis and reliable differentiation of these rare benign tumors and tumor mimickers from the even rarer malignant tumors with subsequent appropriate treatment or watchful waiting is crucial for the clinical outcome. Bone tumors are often a source of diagnostic and therapeutic uncertainty. Thus this European Society of Musculoskeletal Radiology consensus document is intended to help radiologists in their decision making and support discussion among clinicians who deal with patients with suspected or proven bone tumors. Evaluating these tumors starts with a patient history and physical examination. Radiography is the principal imaging modality and often can reliably diagnose a benign bone tumor by providing information about localization, matrix, aggressiveness, size, and (potential) multiplicity. In a significant number of cases, additional imaging is not necessary. Potentially malignant entities recognized by radiography should be referred for magnetic resonance imaging, which also serves as a preoperative local staging modality, with specific technical requirements. Indeterminate tumors, or tumors in which therapy depends on histology results, should be biopsied. For biopsy, we strongly recommend referral to a specialist regional sarcoma treatment center (RSTC), where a multidisciplinary tumor team, including a specialist pathologist, radiologist, and sarcoma surgeon, are involved. Additional staging modalities are entity specific and should be performed according to the recommendations of the RSTC.

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