Aclan Dogan - Academia.edu (original) (raw)
Papers by Aclan Dogan
Eur J Neurosci, 2008
Rao, VLR, Dogan, A., Bowen, KK, Todd, KG and Dempsey, RJ (2001), Antisense knockdown of the glial... more Rao, VLR, Dogan, A., Bowen, KK, Todd, KG and Dempsey, RJ (2001), Antisense knockdown of the glial glutamate transporter GLT-1 exacerbates hippocampal neuronal damage following traumatic injury to rat brain. European Journal of Neuroscience, 13: 119128. ...
Neurology, Feb 12, 2013
ABSTRACT OBJECT Deep vein thrombosis (DVT) is a common complication of aneurysmal subarachnoid he... more ABSTRACT OBJECT Deep vein thrombosis (DVT) is a common complication of aneurysmal subarachnoid hemorrhage (aSAH). The time period of greatest risk for developing DVT after aSAH is not currently known. aSAH induces a prothrombotic state, which may contribute to DVT formation. Using repeated ultrasound screening, the hypothesis that patients would be at greatest risk for developing DVT in the subacute post-rupture period was tested. METHODS One hundred ninety-eight patients with aSAH admitted to the Oregon Health & Science University Neurosciences Intensive Care Unit between April 2008 and March 2012 were included in a retrospective analysis. Ultrasound screening was performed every 5.2 ± 3.3 days between admission and discharge. The chi-square test was used to compare DVT incidence during different time periods of interest. Patient baseline characteristics as well as stroke severity and hospital complications were evaluated in univariate and multivariate analyses. RESULTS Forty-two (21%) of 198 patients were diagnosed with DVT, and 3 (2%) of 198 patients were symptomatic. Twenty-nine (69%) of the 42 cases of DVT were first detected between Days 3 and 14, compared with 3 cases (7%) detected between Days 0 and 3 and 10 cases (24%) detected after Day 14 (p < 0.05). The postrupture 5-day window of highest risk for DVT development was between Days 5 and 9 (40%, p < 0.05). In the multivariate analysis, length of hospital stay and use of mechanical prophylaxis alone were significantly associated with DVT formation. CONCLUSIONS DVT formation most commonly occurs in the first 2 weeks following aSAH, with detection in this cohort peaking between Days 5 and 9. Chemoprophylaxis is associated with a significantly lower incidence of DVT.
General Pharmacology the Vascular System, Oct 1, 1996
This investigation was undertaken to study the effect of iloprost, a stable analogue of prostacyc... more This investigation was undertaken to study the effect of iloprost, a stable analogue of prostacyclin, on infarct size after permanent focal cerebral ischemia in the rabbit. Forty-two adult rabbits were subjected to left middle cerebral artery occlusion via the transorbital route. Fourteen rabbits received an intravenous (IV) infusion of 30 ~tg/kg iloprost, 7 rabbits received an IV infusion of 10 ~g/ kg, and 9 rabbits received an IV infusion of 20 l~g/kg iloprost. Twelve rabbits received an intravenous infusion of saline. Treatment with iloprost started immediately after middle cerebral artery occlusion and continued for 1 h. After killing the animals, brains were removed and five coronal slices were incubated in a 2,3,5-triphenyltetrazolium chloride solution to determine the infarct size. Treatment with 30 I~g/kg iloprost significantly reduced the infarct size compared with treatment with saline (3.49_ + 2.79% vs. 9.03 _+4.26%, P<0.001 ), but the lower doses of iloprost did not have a beneficial effect on the size of the infarct. These results suggest that intravenous iloprost treatment after occlusion has a highly protective effect without any side effects such as hypotension.
Surgical Neurology, Aug 1, 2008
Background: The following technical case report illustrates the use of multiple imaging modalitie... more Background: The following technical case report illustrates the use of multiple imaging modalities including 3D CTV with frameless stereotactic navigation for intraoperative planning and localization for surgical obliteration of a cranial dAVF with leptomeningeal drainage. Case Description: This 65-year-old man presented with an asymptomatic occipital dAVF with leptomeningeal drainage. In addition to cerebral angiography, a CTV with 3D reconstruction was performed, which provided excellent visualization of the dAVF and clarified its pattern of drainage. The dAVF was supplied by a middle meningeal artery branch that drained into an occipital cortical vein, which then retrograde filled the vein of Labbé. Frameless stereotactic navigation with the imported CTV images was used to plan the craniotomy and to localize the leptomeningeal draining vein and vein of Labbé. The draining vein of the fistula was successfully ligated and divided while preserving flow in the vein of Labbé. Postoperative angiogram demonstrated complete obliteration of the dAVF. Conclusion: Integration of a 3D reconstructed CTV with conventional angiographic information optimized our surgical understanding of the spatial anatomy of this dAVF and its pattern of venous drainage. Applying the CTV with frameless stereotaxy allowed for safe obliteration of the dAVF while preserving the vein of Labbé.
Journal of Neurosurgery, 2015
OBJECT Deep vein thrombosis (DVT) is a common complication of aneurysmal subarachnoid hemorrhage ... more OBJECT Deep vein thrombosis (DVT) is a common complication of aneurysmal subarachnoid hemorrhage (aSAH). The time period of greatest risk for developing DVT after aSAH is not currently known. aSAH induces a prothrombotic state, which may contribute to DVT formation. Using repeated ultrasound screening, the hypothesis that patients would be at greatest risk for developing DVT in the subacute post-rupture period was tested. METHODS One hundred ninety-eight patients with aSAH admitted to the Oregon Health &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; Science University Neurosciences Intensive Care Unit between April 2008 and March 2012 were included in a retrospective analysis. Ultrasound screening was performed every 5.2 ± 3.3 days between admission and discharge. The chi-square test was used to compare DVT incidence during different time periods of interest. Patient baseline characteristics as well as stroke severity and hospital complications were evaluated in univariate and multivariate analyses. RESULTS Forty-two (21%) of 198 patients were diagnosed with DVT, and 3 (2%) of 198 patients were symptomatic. Twenty-nine (69%) of the 42 cases of DVT were first detected between Days 3 and 14, compared with 3 cases (7%) detected between Days 0 and 3 and 10 cases (24%) detected after Day 14 (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The postrupture 5-day window of highest risk for DVT development was between Days 5 and 9 (40%, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). In the multivariate analysis, length of hospital stay and use of mechanical prophylaxis alone were significantly associated with DVT formation. CONCLUSIONS DVT formation most commonly occurs in the first 2 weeks following aSAH, with detection in this cohort peaking between Days 5 and 9. Chemoprophylaxis is associated with a significantly lower incidence of DVT.
Neurological research, 1998
In models of middle cerebral artery occlusion using intraluminal suture, the size and the distrib... more In models of middle cerebral artery occlusion using intraluminal suture, the size and the distribution of ischemic injury vary considerably among laboratories. In transcranial models of cerebral ischemia, a more consistent cerebral ischemic lesion is seen in Spontaneously Hypertensive rats (SHR). In the present study, we performed intraluminal suture occlusion of the MCA in SHR and compared its reproducibility with those in Sprague-Dawley (SD) rats. Male SHR and SD rats were anesthetized with halothane and subjected to 2 h of temporary middle cerebral artery occlusion by an intraluminal suture. Comparisons of regional cerebral blood flow figures taken throughout the experiment and lesion volume figures taken at 24 h after occlusion were made between the two groups. Total lesion volume in the SHR group was 263.6+/-30.5 mm3 (mean +/- SD), significantly larger and less variable than that in the SD group (145.4+/-123.7 mm3, p < 0.02). Throughout the ischemic period there was a tenden...
Background: The following technical case report illustrates the use of multiple imaging modalitie... more Background: The following technical case report illustrates the use of multiple imaging modalities including 3D CTV with frameless stereotactic navigation for intraoperative planning and localization for surgical obliteration of a cranial dAVF with leptomeningeal drainage. Case Description: This 65-year-old man presented with an asymptomatic occipital dAVF with leptomeningeal drainage. In addition to cerebral angiography, a CTV with 3D reconstruction was performed, which provided excellent visualization of the dAVF and clarified its pattern of drainage. The dAVF was supplied by a middle meningeal artery branch that drained into an occipital cortical vein, which then retrograde filled the vein of Labbé. Frameless stereotactic navigation with the imported CTV images was used to plan the craniotomy and to localize the leptomeningeal draining vein and vein of Labbé. The draining vein of the fistula was successfully ligated and divided while preserving flow in the vein of Labbé. Postoperative angiogram demonstrated complete obliteration of the dAVF. Conclusion: Integration of a 3D reconstructed CTV with conventional angiographic information optimized our surgical understanding of the spatial anatomy of this dAVF and its pattern of venous drainage. Applying the CTV with frameless stereotaxy allowed for safe obliteration of the dAVF while preserving the vein of Labbé.
Journal of neurointerventional surgery, 2013
Due to anatomic features, including wide necks and incorporation of important branches, endovascu... more Due to anatomic features, including wide necks and incorporation of important branches, endovascular coiling of middle cerebral artery (MCA) aneurysms has proved challenging. Stent assisted embolization may increase the likelihood of successful treatment. Consecutive patients undergoing stent assisted coil embolization utilizing the Neuroform stent from 2004 to 2009 were identified by hospital billing records. Procedural and clinical information-including procedure related mortality and morbidity and long term outcomes-were then obtained by retrospective chart review. Treatment was successful in 22/23 (96%) patients. Median age was 61 years and 16/22 (73%) were women. Aneurysm size was: <5 mm in 5/22 (23%); 5-9 mm in 14/22 (64%); and ≥10 mm in 3/22 (14%) patients. There were four periprocedural complications (including one stroke and one intraprocedural rupture), none associated with neurological dysfunction. Angiographic follow-up was available in 18/22 (82%) and clinical follow...
Journal of NeuroInterventional Surgery, 2011
Lumboperitoneal shunt (LPS), ventriculoperitoneal shunt (VPS) and optic nerve sheath fenestration... more Lumboperitoneal shunt (LPS), ventriculoperitoneal shunt (VPS) and optic nerve sheath fenestration (ONSF) are accepted surgical therapies for medically refractory idiopathic intracranial hypertension (IIH). In the subset of patients with IIH and venous sinus stenosis, dural venous sinus stenting has emerged as an alternative surgical approach. All cases of dural stents for IIH at our institution were retrospectively reviewed. Eligibility criteria included medically refractory IIH with documented papilledema and dural venous sinus stenosis of the dominant venous outflow system (gradient ≥10 mm Hg). Fifteen cases (all women) of mean age 34 years were identified. All had failed medical therapy and six had failed surgical intervention. Technical success was achieved in all patients without major periprocedural complications. The mean preprocedural gradient across the venous stenosis was reduced from 24 mm Hg before the procedure to 4 mm Hg after the procedure. Headache resolved or improved in 10 patients. Papilledema resolved in all patients and visual acuity stabilized or improved in 14 patients. There were no instances of restenosis among the 14 patients with follow-up imaging. In this small case series, dural sinus stenting for IIH was performed safely with a high degree of technical success and with excellent clinical outcomes. These results suggest that angioplasty and stenting for the treatment of medically refractory IIH in patients with dural sinus stenosis warrants further investigation as an alternative to LPS, VPS and ONSF.
Journal of Neurological Surgery Part B: Skull Base, 2015
Objective To analyze whether cavernous sinus sampling (CSS) and dynamic magnetic resonance imagin... more Objective To analyze whether cavernous sinus sampling (CSS) and dynamic magnetic resonance imaging (dMRI) are consistent with intraoperative findings in Cushing disease (CD) patients. Design Retrospective outcomes study. Setting Oregon Health &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; Science University; 2006 and 2013. Participants A total of 37 CD patients with preoperative dMRI and CSS to confirm central adrenocorticotropic hormone (ACTH) hypersecretion. Patients were 78% female; mean age was 41 years (at diagnosis), and all had a minimum of 6 months of follow-up. Main Outcome Measures Correlations among patient characteristics, dMRI measurements, CSS results, and intraoperative findings. Results All CSS indicated presence of CD. Eight of 37 patients had no identifiable tumor on dMRI. Three of 37 patients had no tumor at surgery. dMRI tumor size was inversely correlated with age (rs = - 0.4; p = 0.01) and directly correlated to intraoperative lateralization (rs = 0.3; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Preoperative dMRI was directly correlated to intraoperative lateralization (rs = 0.5; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.002). CSS lateralization showed no correlation with intraoperative findings (rs = 0.145; p = 0.40) or lateralization observed on preoperative dMRI (rs = 0.17; p = 0.29). Postoperative remission rate was 68%. Conclusion dMRI localization was most consistent with intraoperative findings; CSS results were less reliable. Results suggest that small ACTH-secreting tumors continue to pose a challenge to reliable preoperative localization.
Journal of Neurosurgery: Spine, 2015
Intrathecal catheter placement into the lumbar cistern has varied indications, including drug del... more Intrathecal catheter placement into the lumbar cistern has varied indications, including drug delivery and CSF diversion. These Silastic catheters are elastic and durable; however, catheter-associated malfunctions are well reported in the literature. Fractured catheters are managed with some variability, but entirely intradural retained fragments are often managed conservatively with observation. The authors describe a case of a 70-year-old man with an implanted intrathecal morphine pump for failed back surgery syndrome who presented to an outside hospital with a history of headache, neck pain, nausea, and photophobia of 3 days' duration. He also described mild weakness and intermittent numbness of both legs. Unenhanced head CT demonstrated subarachnoid hemorrhage (SAH). A right C-5 hemilaminectomy was performed. This case is unique in that there was no indication that the lumbar intrathecal catheter had fractured prior to the patient's presentation with SAH. This case demonstrates that intrathecal catheter fragments are mobile and can precipitate intracranial morbidity. Extrication of known fragments is safe and should be attempted to prevent further neurosurgical morbidity.
Neurocritical Care, 2014
Background Patients recovering from aneurysmal subarachnoid hemorrhage (SAH) are at risk for deve... more Background Patients recovering from aneurysmal subarachnoid hemorrhage (SAH) are at risk for developing delayed cerebral ischemia (DCI). Experimental and human studies implicate the vasoconstrictor P450 eicosanoid 20hydroxyeicosatetraenoic acid (20-HETE) in the pathogenesis of DCI. To date, no studies have evaluated the role of vasodilator epoxyeicosatrienoic acids (EETs) in DCI. Methods Using mass spectrometry, we measured P450 eicosanoids in cerebrospinal fluid (CSF) from 34 SAH patients from 1 to 14 days after admission. CSF eicosanoid levels were compared in patients who experienced DCI versus those who did not. We then studied the effect of EETs in a model of SAH using mice lacking the enzyme soluble epoxide hydrolase (sEH), which catabolizes EETs into their inactive diol. To assess changes in vessel morphology and cortical perfusion in the mouse brain, we used optical microangiography, a non-invasive coherence-based imaging technique.
General Pharmacology: The Vascular System, 1996
This investigation was undertaken to study the effect of iloprost, a stable analogue of prostacyc... more This investigation was undertaken to study the effect of iloprost, a stable analogue of prostacyclin, on infarct size after permanent focal cerebral ischemia in the rabbit. Forty-two adult rabbits were subjected to left middle cerebral artery occlusion via the transorbital route. Fourteen rabbits received an intravenous (IV) infusion of 30 ~tg/kg iloprost, 7 rabbits received an IV infusion of 10 ~g/ kg, and 9 rabbits received an IV infusion of 20 l~g/kg iloprost. Twelve rabbits received an intravenous infusion of saline. Treatment with iloprost started immediately after middle cerebral artery occlusion and continued for 1 h. After killing the animals, brains were removed and five coronal slices were incubated in a 2,3,5-triphenyltetrazolium chloride solution to determine the infarct size. Treatment with 30 I~g/kg iloprost significantly reduced the infarct size compared with treatment with saline (3.49_ + 2.79% vs. 9.03 _+4.26%, P<0.001 ), but the lower doses of iloprost did not have a beneficial effect on the size of the infarct. These results suggest that intravenous iloprost treatment after occlusion has a highly protective effect without any side effects such as hypotension.
There is increasing evidence that the elevated levels of polyamines play an important role in the... more There is increasing evidence that the elevated levels of polyamines play an important role in the secondary injury following traumatic . . brain injury TBI . Ornithine decarboxylase ODC is the rate-limiting enzyme of polyamine biosynthesis. Presently, we measured the ODC protein levels by Western blot analysis in the cerebral cortex of rats sacrificed at 2 h, 6 h, 24
Neurochemistry International, 2000
Glial (GLT-1 and GLAST) and neuronal (EAAC1) high-anity transporters mediate the sodium dependent... more Glial (GLT-1 and GLAST) and neuronal (EAAC1) high-anity transporters mediate the sodium dependent glutamate reuptake in mammalian brain. Their dysfunction leads to neuronal damage by allowing glutamate to remain in the synaptic cleft for a longer duration. The purpose of the present study is to understand their contribution to the ischemic delayed neuronal death seen in gerbil hippocampus following transient global cerebral ischemia. The protein levels of these three transporters were studied by immunoblotting as a function of reperfusion time (6 h to 7 days) following a 10 min occlusion of bilateral common carotid arteries in gerbils. In the vulnerable hippocampus, there was a signi®cant decrease in the protein levels of GLT-1 (by 36± 46%, P < 0.05; between 1 and 3 days of reperfusion) and EAAC1 (by 42±68%, P < 0.05; between 1 and 7 days of reperfusion). Histopathological evaluation showed no neuronal loss up to 2 days of reperfusion but an extensive neuronal loss (by H84%, P < 0.01) at 7 days of reperfusion in the hippocampal CA1 region. The time frame of GLT-1 dysfunction (1±3 days of reperfusion) precedes the initiation of delayed neuronal death (2±3 days of reperfusion). This suggests GLT-1 dysfunction as a contributing factor for the hippocampal neuronal death following transient global cerebral ischemia. Furthermore, decreased EAAC1 levels may contribute to GABAergic dysfunction and excitatory/inhibitory imbalance following transient global ischemia. #
Journal of Neurological Surgery Part B: Skull Base, 2012
Pituitary, 2012
Postoperative serum cortisol is used as an indicator of Cushing&amp;amp;amp;amp;amp;amp;a... more Postoperative serum cortisol is used as an indicator of Cushing&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease (CD) remission following transsphenoidal surgery (TSS) and guides (controversially) the need for immediate adjuvant treatment for CD. We investigated postoperative cortisol and adrenocorticotropic hormone (ACTH) levels as predictors of remission/recurrence in CD in a large retrospective cohort of patients with pathologically confirmed CD, over 6 years at a single institution. Midnight and morning cortisol, and ACTH at 24-48 h postoperatively (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;24 h after last hydrocortisone dose) were measured. Remission was defined as normal 24-h urine free cortisol, normal midnight salivary cortisol, a normal dexamethasone-corticotropin releasing hormone (CRH) test or continued need for hydrocortisone, assessed periodically. Statistical analysis was performed using PASW 18. Follow up data was available for 52 patients (38 females and 14 males), median follow up was 16.5 month (range 2-143 months), median age was 45 years (range 21-72 years), 28 tumors were microadenomas and 16 were macroadenomas, and in eight cases no tumor was observed on magnetic resonance imaging. No patient with postoperative cortisol levels &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl were found to be in remission. Ten of the 52 patients with cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl by postoperative day 1-2 underwent a second TSS within 7 days. Forty-three patients (82.7%) achieved CD remission (36 after one TSS and 7 after a second early TSS) and six patients suffered disease recurrence (mean 39.2 ± 52.4 months). An immediate second TSS induced additional hormonal deficiencies (diabetes insipidus) in three patients with no surgical complications. Persistent disease was noted in nine patients despite three patients having an immediate second TSS. Positive predictive value for remission of cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2 mcg/dl and ACTH &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;5 pg/ml was 100%. Cortisol and ACTH levels (at all postoperative time points and at 2 months) were correlated (r = 0.37, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Nadir serum cortisol of ≤2 mcg/dl and ACTH &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;5 pg/ml predicted remission (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.005), but no level predicted lack of recurrence. Immediate postoperative ACTH/cortisol did not predict length of remission. No patients with postoperative cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl were observed to have delayed remission; all required additional treatment. There was no significant difference in age, body mass index, tumor size and length of follow-up between postoperative cortisol groups: cortisol ≤2 mcg/dl, cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;5 mcg/dl and cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl. Immediate postoperative cortisol levels should routinely be obtained in CD patients post TSS, until better tools to identify early remission are available. Immediate repeat TSS could be beneficial in patients with cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl and positive CD pathology: our combined (micro- and macroadenomas) remission rate with this approach was 82.7%. ACTH measurements correlate well with cortisol. However, because no single cortisol or ACTH cutoff value excludes all recurrences, patients require long-term clinical and biochemical follow-up. Further research is needed in this area.
Journal of Neurosurgery, 2015
OBJECT Middle fossa floor dehiscence (MFFD) can present as multiple syndromes depending on dehisc... more OBJECT Middle fossa floor dehiscence (MFFD) can present as multiple syndromes depending on dehiscence location, tissue herniation, and dural integrity. The authors propose a classification system for MFFD with the potential to guide clinical decision making. METHODS A retrospective analysis of the electronic medical records (years 1995-2012) of patients who had undergone temporal craniotomy for the surgical repair of an MFFD syndrome at a single institution was undertaken. Reviewed data included demographic, operative, presentation, and outcome details. Middle fossa floor dehiscence was classified as follows: Class A, bony dehiscence without herniation of the brain and/or meninges; Class B, herniation of the brain and/or meninges through the middle fossa floor without CSF leakage; Class C, dehiscence with CSF leakage without meningitis; or Class D, dehiscence with meningitis. RESULTS Fifty-one patients, 22 males and 29 females, were included in the analysis. The mean age was 48.7 ± 15.5 years, mean body mass index was 32.65 ± 6.86 kg/m(2), and mean symptom duration was 33 ± 42 months. Seven patients underwent repeat surgery for symptomatic recurrence; therefore, there were 58 surgical encounters. Repair included bony reconstruction with hydroxyapatite with or without resection of encephaloceles and/or repair of a dural defect. According to the MFFD classification system described, 15, 8, 27, and 8 cases were categorized as Class A, B, C, and D, respectively. The prevalence of hearing loss was 87%, 63%, and 70% in Classes A, B, and C, respectively. Vestibular symptoms were more prevalent in Class A. Seven patients reported persistent symptoms at the last follow-up. Transient complications were similar in each classification (13%-25%), and a single permanent complication related to anesthesia was observed. There were no mortalities or severe neurological morbidities in the series. CONCLUSIONS Middle fossa floor dehiscence has a spectrum of clinical presentations. A classification system may help to clarify the diagnosis and guide therapy. Surgery, the mainstay of treatment, is safe and well tolerated.
Eur J Neurosci, 2008
Rao, VLR, Dogan, A., Bowen, KK, Todd, KG and Dempsey, RJ (2001), Antisense knockdown of the glial... more Rao, VLR, Dogan, A., Bowen, KK, Todd, KG and Dempsey, RJ (2001), Antisense knockdown of the glial glutamate transporter GLT-1 exacerbates hippocampal neuronal damage following traumatic injury to rat brain. European Journal of Neuroscience, 13: 119128. ...
Neurology, Feb 12, 2013
ABSTRACT OBJECT Deep vein thrombosis (DVT) is a common complication of aneurysmal subarachnoid he... more ABSTRACT OBJECT Deep vein thrombosis (DVT) is a common complication of aneurysmal subarachnoid hemorrhage (aSAH). The time period of greatest risk for developing DVT after aSAH is not currently known. aSAH induces a prothrombotic state, which may contribute to DVT formation. Using repeated ultrasound screening, the hypothesis that patients would be at greatest risk for developing DVT in the subacute post-rupture period was tested. METHODS One hundred ninety-eight patients with aSAH admitted to the Oregon Health & Science University Neurosciences Intensive Care Unit between April 2008 and March 2012 were included in a retrospective analysis. Ultrasound screening was performed every 5.2 ± 3.3 days between admission and discharge. The chi-square test was used to compare DVT incidence during different time periods of interest. Patient baseline characteristics as well as stroke severity and hospital complications were evaluated in univariate and multivariate analyses. RESULTS Forty-two (21%) of 198 patients were diagnosed with DVT, and 3 (2%) of 198 patients were symptomatic. Twenty-nine (69%) of the 42 cases of DVT were first detected between Days 3 and 14, compared with 3 cases (7%) detected between Days 0 and 3 and 10 cases (24%) detected after Day 14 (p < 0.05). The postrupture 5-day window of highest risk for DVT development was between Days 5 and 9 (40%, p < 0.05). In the multivariate analysis, length of hospital stay and use of mechanical prophylaxis alone were significantly associated with DVT formation. CONCLUSIONS DVT formation most commonly occurs in the first 2 weeks following aSAH, with detection in this cohort peaking between Days 5 and 9. Chemoprophylaxis is associated with a significantly lower incidence of DVT.
General Pharmacology the Vascular System, Oct 1, 1996
This investigation was undertaken to study the effect of iloprost, a stable analogue of prostacyc... more This investigation was undertaken to study the effect of iloprost, a stable analogue of prostacyclin, on infarct size after permanent focal cerebral ischemia in the rabbit. Forty-two adult rabbits were subjected to left middle cerebral artery occlusion via the transorbital route. Fourteen rabbits received an intravenous (IV) infusion of 30 ~tg/kg iloprost, 7 rabbits received an IV infusion of 10 ~g/ kg, and 9 rabbits received an IV infusion of 20 l~g/kg iloprost. Twelve rabbits received an intravenous infusion of saline. Treatment with iloprost started immediately after middle cerebral artery occlusion and continued for 1 h. After killing the animals, brains were removed and five coronal slices were incubated in a 2,3,5-triphenyltetrazolium chloride solution to determine the infarct size. Treatment with 30 I~g/kg iloprost significantly reduced the infarct size compared with treatment with saline (3.49_ + 2.79% vs. 9.03 _+4.26%, P<0.001 ), but the lower doses of iloprost did not have a beneficial effect on the size of the infarct. These results suggest that intravenous iloprost treatment after occlusion has a highly protective effect without any side effects such as hypotension.
Surgical Neurology, Aug 1, 2008
Background: The following technical case report illustrates the use of multiple imaging modalitie... more Background: The following technical case report illustrates the use of multiple imaging modalities including 3D CTV with frameless stereotactic navigation for intraoperative planning and localization for surgical obliteration of a cranial dAVF with leptomeningeal drainage. Case Description: This 65-year-old man presented with an asymptomatic occipital dAVF with leptomeningeal drainage. In addition to cerebral angiography, a CTV with 3D reconstruction was performed, which provided excellent visualization of the dAVF and clarified its pattern of drainage. The dAVF was supplied by a middle meningeal artery branch that drained into an occipital cortical vein, which then retrograde filled the vein of Labbé. Frameless stereotactic navigation with the imported CTV images was used to plan the craniotomy and to localize the leptomeningeal draining vein and vein of Labbé. The draining vein of the fistula was successfully ligated and divided while preserving flow in the vein of Labbé. Postoperative angiogram demonstrated complete obliteration of the dAVF. Conclusion: Integration of a 3D reconstructed CTV with conventional angiographic information optimized our surgical understanding of the spatial anatomy of this dAVF and its pattern of venous drainage. Applying the CTV with frameless stereotaxy allowed for safe obliteration of the dAVF while preserving the vein of Labbé.
Journal of Neurosurgery, 2015
OBJECT Deep vein thrombosis (DVT) is a common complication of aneurysmal subarachnoid hemorrhage ... more OBJECT Deep vein thrombosis (DVT) is a common complication of aneurysmal subarachnoid hemorrhage (aSAH). The time period of greatest risk for developing DVT after aSAH is not currently known. aSAH induces a prothrombotic state, which may contribute to DVT formation. Using repeated ultrasound screening, the hypothesis that patients would be at greatest risk for developing DVT in the subacute post-rupture period was tested. METHODS One hundred ninety-eight patients with aSAH admitted to the Oregon Health &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; Science University Neurosciences Intensive Care Unit between April 2008 and March 2012 were included in a retrospective analysis. Ultrasound screening was performed every 5.2 ± 3.3 days between admission and discharge. The chi-square test was used to compare DVT incidence during different time periods of interest. Patient baseline characteristics as well as stroke severity and hospital complications were evaluated in univariate and multivariate analyses. RESULTS Forty-two (21%) of 198 patients were diagnosed with DVT, and 3 (2%) of 198 patients were symptomatic. Twenty-nine (69%) of the 42 cases of DVT were first detected between Days 3 and 14, compared with 3 cases (7%) detected between Days 0 and 3 and 10 cases (24%) detected after Day 14 (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The postrupture 5-day window of highest risk for DVT development was between Days 5 and 9 (40%, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). In the multivariate analysis, length of hospital stay and use of mechanical prophylaxis alone were significantly associated with DVT formation. CONCLUSIONS DVT formation most commonly occurs in the first 2 weeks following aSAH, with detection in this cohort peaking between Days 5 and 9. Chemoprophylaxis is associated with a significantly lower incidence of DVT.
Neurological research, 1998
In models of middle cerebral artery occlusion using intraluminal suture, the size and the distrib... more In models of middle cerebral artery occlusion using intraluminal suture, the size and the distribution of ischemic injury vary considerably among laboratories. In transcranial models of cerebral ischemia, a more consistent cerebral ischemic lesion is seen in Spontaneously Hypertensive rats (SHR). In the present study, we performed intraluminal suture occlusion of the MCA in SHR and compared its reproducibility with those in Sprague-Dawley (SD) rats. Male SHR and SD rats were anesthetized with halothane and subjected to 2 h of temporary middle cerebral artery occlusion by an intraluminal suture. Comparisons of regional cerebral blood flow figures taken throughout the experiment and lesion volume figures taken at 24 h after occlusion were made between the two groups. Total lesion volume in the SHR group was 263.6+/-30.5 mm3 (mean +/- SD), significantly larger and less variable than that in the SD group (145.4+/-123.7 mm3, p < 0.02). Throughout the ischemic period there was a tenden...
Background: The following technical case report illustrates the use of multiple imaging modalitie... more Background: The following technical case report illustrates the use of multiple imaging modalities including 3D CTV with frameless stereotactic navigation for intraoperative planning and localization for surgical obliteration of a cranial dAVF with leptomeningeal drainage. Case Description: This 65-year-old man presented with an asymptomatic occipital dAVF with leptomeningeal drainage. In addition to cerebral angiography, a CTV with 3D reconstruction was performed, which provided excellent visualization of the dAVF and clarified its pattern of drainage. The dAVF was supplied by a middle meningeal artery branch that drained into an occipital cortical vein, which then retrograde filled the vein of Labbé. Frameless stereotactic navigation with the imported CTV images was used to plan the craniotomy and to localize the leptomeningeal draining vein and vein of Labbé. The draining vein of the fistula was successfully ligated and divided while preserving flow in the vein of Labbé. Postoperative angiogram demonstrated complete obliteration of the dAVF. Conclusion: Integration of a 3D reconstructed CTV with conventional angiographic information optimized our surgical understanding of the spatial anatomy of this dAVF and its pattern of venous drainage. Applying the CTV with frameless stereotaxy allowed for safe obliteration of the dAVF while preserving the vein of Labbé.
Journal of neurointerventional surgery, 2013
Due to anatomic features, including wide necks and incorporation of important branches, endovascu... more Due to anatomic features, including wide necks and incorporation of important branches, endovascular coiling of middle cerebral artery (MCA) aneurysms has proved challenging. Stent assisted embolization may increase the likelihood of successful treatment. Consecutive patients undergoing stent assisted coil embolization utilizing the Neuroform stent from 2004 to 2009 were identified by hospital billing records. Procedural and clinical information-including procedure related mortality and morbidity and long term outcomes-were then obtained by retrospective chart review. Treatment was successful in 22/23 (96%) patients. Median age was 61 years and 16/22 (73%) were women. Aneurysm size was: <5 mm in 5/22 (23%); 5-9 mm in 14/22 (64%); and ≥10 mm in 3/22 (14%) patients. There were four periprocedural complications (including one stroke and one intraprocedural rupture), none associated with neurological dysfunction. Angiographic follow-up was available in 18/22 (82%) and clinical follow...
Journal of NeuroInterventional Surgery, 2011
Lumboperitoneal shunt (LPS), ventriculoperitoneal shunt (VPS) and optic nerve sheath fenestration... more Lumboperitoneal shunt (LPS), ventriculoperitoneal shunt (VPS) and optic nerve sheath fenestration (ONSF) are accepted surgical therapies for medically refractory idiopathic intracranial hypertension (IIH). In the subset of patients with IIH and venous sinus stenosis, dural venous sinus stenting has emerged as an alternative surgical approach. All cases of dural stents for IIH at our institution were retrospectively reviewed. Eligibility criteria included medically refractory IIH with documented papilledema and dural venous sinus stenosis of the dominant venous outflow system (gradient ≥10 mm Hg). Fifteen cases (all women) of mean age 34 years were identified. All had failed medical therapy and six had failed surgical intervention. Technical success was achieved in all patients without major periprocedural complications. The mean preprocedural gradient across the venous stenosis was reduced from 24 mm Hg before the procedure to 4 mm Hg after the procedure. Headache resolved or improved in 10 patients. Papilledema resolved in all patients and visual acuity stabilized or improved in 14 patients. There were no instances of restenosis among the 14 patients with follow-up imaging. In this small case series, dural sinus stenting for IIH was performed safely with a high degree of technical success and with excellent clinical outcomes. These results suggest that angioplasty and stenting for the treatment of medically refractory IIH in patients with dural sinus stenosis warrants further investigation as an alternative to LPS, VPS and ONSF.
Journal of Neurological Surgery Part B: Skull Base, 2015
Objective To analyze whether cavernous sinus sampling (CSS) and dynamic magnetic resonance imagin... more Objective To analyze whether cavernous sinus sampling (CSS) and dynamic magnetic resonance imaging (dMRI) are consistent with intraoperative findings in Cushing disease (CD) patients. Design Retrospective outcomes study. Setting Oregon Health &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; Science University; 2006 and 2013. Participants A total of 37 CD patients with preoperative dMRI and CSS to confirm central adrenocorticotropic hormone (ACTH) hypersecretion. Patients were 78% female; mean age was 41 years (at diagnosis), and all had a minimum of 6 months of follow-up. Main Outcome Measures Correlations among patient characteristics, dMRI measurements, CSS results, and intraoperative findings. Results All CSS indicated presence of CD. Eight of 37 patients had no identifiable tumor on dMRI. Three of 37 patients had no tumor at surgery. dMRI tumor size was inversely correlated with age (rs = - 0.4; p = 0.01) and directly correlated to intraoperative lateralization (rs = 0.3; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Preoperative dMRI was directly correlated to intraoperative lateralization (rs = 0.5; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.002). CSS lateralization showed no correlation with intraoperative findings (rs = 0.145; p = 0.40) or lateralization observed on preoperative dMRI (rs = 0.17; p = 0.29). Postoperative remission rate was 68%. Conclusion dMRI localization was most consistent with intraoperative findings; CSS results were less reliable. Results suggest that small ACTH-secreting tumors continue to pose a challenge to reliable preoperative localization.
Journal of Neurosurgery: Spine, 2015
Intrathecal catheter placement into the lumbar cistern has varied indications, including drug del... more Intrathecal catheter placement into the lumbar cistern has varied indications, including drug delivery and CSF diversion. These Silastic catheters are elastic and durable; however, catheter-associated malfunctions are well reported in the literature. Fractured catheters are managed with some variability, but entirely intradural retained fragments are often managed conservatively with observation. The authors describe a case of a 70-year-old man with an implanted intrathecal morphine pump for failed back surgery syndrome who presented to an outside hospital with a history of headache, neck pain, nausea, and photophobia of 3 days' duration. He also described mild weakness and intermittent numbness of both legs. Unenhanced head CT demonstrated subarachnoid hemorrhage (SAH). A right C-5 hemilaminectomy was performed. This case is unique in that there was no indication that the lumbar intrathecal catheter had fractured prior to the patient's presentation with SAH. This case demonstrates that intrathecal catheter fragments are mobile and can precipitate intracranial morbidity. Extrication of known fragments is safe and should be attempted to prevent further neurosurgical morbidity.
Neurocritical Care, 2014
Background Patients recovering from aneurysmal subarachnoid hemorrhage (SAH) are at risk for deve... more Background Patients recovering from aneurysmal subarachnoid hemorrhage (SAH) are at risk for developing delayed cerebral ischemia (DCI). Experimental and human studies implicate the vasoconstrictor P450 eicosanoid 20hydroxyeicosatetraenoic acid (20-HETE) in the pathogenesis of DCI. To date, no studies have evaluated the role of vasodilator epoxyeicosatrienoic acids (EETs) in DCI. Methods Using mass spectrometry, we measured P450 eicosanoids in cerebrospinal fluid (CSF) from 34 SAH patients from 1 to 14 days after admission. CSF eicosanoid levels were compared in patients who experienced DCI versus those who did not. We then studied the effect of EETs in a model of SAH using mice lacking the enzyme soluble epoxide hydrolase (sEH), which catabolizes EETs into their inactive diol. To assess changes in vessel morphology and cortical perfusion in the mouse brain, we used optical microangiography, a non-invasive coherence-based imaging technique.
General Pharmacology: The Vascular System, 1996
This investigation was undertaken to study the effect of iloprost, a stable analogue of prostacyc... more This investigation was undertaken to study the effect of iloprost, a stable analogue of prostacyclin, on infarct size after permanent focal cerebral ischemia in the rabbit. Forty-two adult rabbits were subjected to left middle cerebral artery occlusion via the transorbital route. Fourteen rabbits received an intravenous (IV) infusion of 30 ~tg/kg iloprost, 7 rabbits received an IV infusion of 10 ~g/ kg, and 9 rabbits received an IV infusion of 20 l~g/kg iloprost. Twelve rabbits received an intravenous infusion of saline. Treatment with iloprost started immediately after middle cerebral artery occlusion and continued for 1 h. After killing the animals, brains were removed and five coronal slices were incubated in a 2,3,5-triphenyltetrazolium chloride solution to determine the infarct size. Treatment with 30 I~g/kg iloprost significantly reduced the infarct size compared with treatment with saline (3.49_ + 2.79% vs. 9.03 _+4.26%, P<0.001 ), but the lower doses of iloprost did not have a beneficial effect on the size of the infarct. These results suggest that intravenous iloprost treatment after occlusion has a highly protective effect without any side effects such as hypotension.
There is increasing evidence that the elevated levels of polyamines play an important role in the... more There is increasing evidence that the elevated levels of polyamines play an important role in the secondary injury following traumatic . . brain injury TBI . Ornithine decarboxylase ODC is the rate-limiting enzyme of polyamine biosynthesis. Presently, we measured the ODC protein levels by Western blot analysis in the cerebral cortex of rats sacrificed at 2 h, 6 h, 24
Neurochemistry International, 2000
Glial (GLT-1 and GLAST) and neuronal (EAAC1) high-anity transporters mediate the sodium dependent... more Glial (GLT-1 and GLAST) and neuronal (EAAC1) high-anity transporters mediate the sodium dependent glutamate reuptake in mammalian brain. Their dysfunction leads to neuronal damage by allowing glutamate to remain in the synaptic cleft for a longer duration. The purpose of the present study is to understand their contribution to the ischemic delayed neuronal death seen in gerbil hippocampus following transient global cerebral ischemia. The protein levels of these three transporters were studied by immunoblotting as a function of reperfusion time (6 h to 7 days) following a 10 min occlusion of bilateral common carotid arteries in gerbils. In the vulnerable hippocampus, there was a signi®cant decrease in the protein levels of GLT-1 (by 36± 46%, P < 0.05; between 1 and 3 days of reperfusion) and EAAC1 (by 42±68%, P < 0.05; between 1 and 7 days of reperfusion). Histopathological evaluation showed no neuronal loss up to 2 days of reperfusion but an extensive neuronal loss (by H84%, P < 0.01) at 7 days of reperfusion in the hippocampal CA1 region. The time frame of GLT-1 dysfunction (1±3 days of reperfusion) precedes the initiation of delayed neuronal death (2±3 days of reperfusion). This suggests GLT-1 dysfunction as a contributing factor for the hippocampal neuronal death following transient global cerebral ischemia. Furthermore, decreased EAAC1 levels may contribute to GABAergic dysfunction and excitatory/inhibitory imbalance following transient global ischemia. #
Journal of Neurological Surgery Part B: Skull Base, 2012
Pituitary, 2012
Postoperative serum cortisol is used as an indicator of Cushing&amp;amp;amp;amp;amp;amp;a... more Postoperative serum cortisol is used as an indicator of Cushing&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease (CD) remission following transsphenoidal surgery (TSS) and guides (controversially) the need for immediate adjuvant treatment for CD. We investigated postoperative cortisol and adrenocorticotropic hormone (ACTH) levels as predictors of remission/recurrence in CD in a large retrospective cohort of patients with pathologically confirmed CD, over 6 years at a single institution. Midnight and morning cortisol, and ACTH at 24-48 h postoperatively (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;24 h after last hydrocortisone dose) were measured. Remission was defined as normal 24-h urine free cortisol, normal midnight salivary cortisol, a normal dexamethasone-corticotropin releasing hormone (CRH) test or continued need for hydrocortisone, assessed periodically. Statistical analysis was performed using PASW 18. Follow up data was available for 52 patients (38 females and 14 males), median follow up was 16.5 month (range 2-143 months), median age was 45 years (range 21-72 years), 28 tumors were microadenomas and 16 were macroadenomas, and in eight cases no tumor was observed on magnetic resonance imaging. No patient with postoperative cortisol levels &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl were found to be in remission. Ten of the 52 patients with cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl by postoperative day 1-2 underwent a second TSS within 7 days. Forty-three patients (82.7%) achieved CD remission (36 after one TSS and 7 after a second early TSS) and six patients suffered disease recurrence (mean 39.2 ± 52.4 months). An immediate second TSS induced additional hormonal deficiencies (diabetes insipidus) in three patients with no surgical complications. Persistent disease was noted in nine patients despite three patients having an immediate second TSS. Positive predictive value for remission of cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;2 mcg/dl and ACTH &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;5 pg/ml was 100%. Cortisol and ACTH levels (at all postoperative time points and at 2 months) were correlated (r = 0.37, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Nadir serum cortisol of ≤2 mcg/dl and ACTH &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;5 pg/ml predicted remission (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.005), but no level predicted lack of recurrence. Immediate postoperative ACTH/cortisol did not predict length of remission. No patients with postoperative cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl were observed to have delayed remission; all required additional treatment. There was no significant difference in age, body mass index, tumor size and length of follow-up between postoperative cortisol groups: cortisol ≤2 mcg/dl, cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;5 mcg/dl and cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl. Immediate postoperative cortisol levels should routinely be obtained in CD patients post TSS, until better tools to identify early remission are available. Immediate repeat TSS could be beneficial in patients with cortisol &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;10 mcg/dl and positive CD pathology: our combined (micro- and macroadenomas) remission rate with this approach was 82.7%. ACTH measurements correlate well with cortisol. However, because no single cortisol or ACTH cutoff value excludes all recurrences, patients require long-term clinical and biochemical follow-up. Further research is needed in this area.
Journal of Neurosurgery, 2015
OBJECT Middle fossa floor dehiscence (MFFD) can present as multiple syndromes depending on dehisc... more OBJECT Middle fossa floor dehiscence (MFFD) can present as multiple syndromes depending on dehiscence location, tissue herniation, and dural integrity. The authors propose a classification system for MFFD with the potential to guide clinical decision making. METHODS A retrospective analysis of the electronic medical records (years 1995-2012) of patients who had undergone temporal craniotomy for the surgical repair of an MFFD syndrome at a single institution was undertaken. Reviewed data included demographic, operative, presentation, and outcome details. Middle fossa floor dehiscence was classified as follows: Class A, bony dehiscence without herniation of the brain and/or meninges; Class B, herniation of the brain and/or meninges through the middle fossa floor without CSF leakage; Class C, dehiscence with CSF leakage without meningitis; or Class D, dehiscence with meningitis. RESULTS Fifty-one patients, 22 males and 29 females, were included in the analysis. The mean age was 48.7 ± 15.5 years, mean body mass index was 32.65 ± 6.86 kg/m(2), and mean symptom duration was 33 ± 42 months. Seven patients underwent repeat surgery for symptomatic recurrence; therefore, there were 58 surgical encounters. Repair included bony reconstruction with hydroxyapatite with or without resection of encephaloceles and/or repair of a dural defect. According to the MFFD classification system described, 15, 8, 27, and 8 cases were categorized as Class A, B, C, and D, respectively. The prevalence of hearing loss was 87%, 63%, and 70% in Classes A, B, and C, respectively. Vestibular symptoms were more prevalent in Class A. Seven patients reported persistent symptoms at the last follow-up. Transient complications were similar in each classification (13%-25%), and a single permanent complication related to anesthesia was observed. There were no mortalities or severe neurological morbidities in the series. CONCLUSIONS Middle fossa floor dehiscence has a spectrum of clinical presentations. A classification system may help to clarify the diagnosis and guide therapy. Surgery, the mainstay of treatment, is safe and well tolerated.