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Amir R. Dehdashti

A 29-year-old woman is diagnosed with a large broad-base right ophthalmic artery aneurysm. Despite an intact visual field, she complained of mild right visual blurriness. Between endovascular and surgical treatments, surgery was favored due to her young age. It was decided to perform the surgery with simultaneous endovascular temporary carotid balloon occlusion. A right pterional craniotomy and intradural anterior clinoidectomy were performed, the balloon was positioned in the petrous carotid, and the distal durai ring was opened exposing the proximal neck. Under temporary proximal carotid balloon occlusion and distal carotid clip occlusion, the aneurysm was fully dissected and clipped. Intraoperative angiogram confirmed complete aneurysm occlusion and patency of the ophthalmic artery. The patient's neurological exam remained unchanged.

The video can be found here: http://youtu.be/BIQKTl9bDqA.

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Amir R. Dehdashti

Ruptured aneurysms with intraparenchymal hematoma and mass effect are primarily treated by surgical clipping. In this video presentation, a 68 year old male with a large ruptured right ICA bifurcation aneurysm is presented. Patient's neurological exam was rapidly deteriorating, therefore the patient was transferred to the operating theater after initial evaluation by CT and CT angiogram. A pterional craniotomy was performed, the frontal hematoma was partially removed and the aneurysm was clipped. Residual hematoma was removed after securing the aneurysm and the aneurysm dome was punctured(detail of surgical clipping in the video). Patient made a good recovery at 2 weeks post-op with complete recovery of left sided weakness, and some remaining cognitive deficit.

The video can be found here: http://youtu.be/dKFWptdgC4M.

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Amrit Chiluwal and Amir R. Dehdashti

Grade III Spetzler-Martin arteriovenous malformations (AVMs) are a distinct subgroup of brain AVMs. Their variety in terms of location, type of venous drainage, and size makes them the most heterogenous group in the AVM classification. The surgical risk of treatment is also variable depending on the specifics of a given Grade III AVM. In this video illustration, the authors describe the technical nuances of surgical resection of a very complex Grade III left posterior temporal AVM. According to supplementary grading, the unruptured aspect and patient age give this lesion a Grade III; therefore, the combined grading gives the patient a score of 6, which puts him at moderate risk of morbidity for surgery. The indication for surgery was based on the patient’s young age, lifetime risk of hemorrhage, and the location of the AVM in the left inferior/posterior temporal gyrus.

The patient underwent 2 sessions of preoperative embolization of the posterior cerebral artery and the external carotid artery feeders prior to craniotomy. The day after the second embolization, the patient was operated on via a posterior temporobasal craniotomy. The dural supply attached to the draining vein was left intact during the dural exposure. The detail of the AVM resection is described in the video clip. A total resection was achieved, and the patient’s neurological examination was intact after the procedure.

The video can be found here: https://youtu.be/fj5Cxw3kpXQ.

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Georgios Klironomos and Amir R. Dehdashti

Tuberculum sella meningiomas can be approached through lateral approaches including pterional/orbitozygomatic craniotomies, frontobasal craniotomy, or through expanded endoscopic transsphenoidal approaches. The authors present the case of a 60-year-old male who presented with bitemporal hemianopia and significant right-side visual acuity compromise due to a large tuberculum sella meningioma. The tumor had an important extension to the posterior fossa. A right orbitozygomatic trans-sylvian approach was deemed most suitable to tackle the posterior extension of the tumor. Some operative nuances are detailed in the video including dissection of the tumor off the carotid artery, basilar bifurcation, and small thalamoperforators attached to the tumor. Postoperatively, the patient’s bilateral hemianopia improved significantly, but his right visual activity remained unchanged. The remaining part of the tumor in the sella and midclivus was addressed with a second-stage expanded endoscopic transclival approach.

The video can be found here: https://youtu.be/KbewhlT2FWs.

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Amir R. Dehdashti and Fred Gentili

Object

Transsphenoidal pituitary surgery is the primary therapy for Cushing disease because of its potential to produce lasting remission without the need for long-term drug or hormone replacement therapy. The authors evaluated the current role of pure endoscopic endonasal pituitary surgery in the treatment of Cushing disease.

Methods

Twenty-five patients underwent pure endoscopic surgery for confirmed Cushing disease. Thirteen patients had microadenomas and seven had macroadenomas; magnetic resonance images obtained in five patients were only suspicious or nondiagnostic, and thus they underwent inferior petrosal sinus sampling. Two patients had evidence of cavernous sinus involvement. Final histological results were consistent with adrenocorticotropin hormone (ACTH)–secreting adenoma in 20 patients.

Results

Twenty patients (80%) had clinical remission and laboratory confirmation of hypocortisolemia (serum cortisol < 100 nmol/L requiring substitution therapy), suppression to low-dose dexamethasone, and normal 24-hour urinary free cortisol. The median follow-up period was 17 months (range 3–32 months). There was no recurrence at the time of the last follow-up. Three patients presented with new anterior pituitary deficiency, but no one had permanent diabetes insipidus. In one patient a cerebrospinal fluid leak developed but later resolved following lumbar drainage. Treatment failure was attributable to involvement of the cavernous sinus in two patients, incomplete tumor removal in one, negative exploration in one, and nodular corticotroph hyperplasia of the pituitary gland in one.

Conclusions

Early results indicated that endoscopic endonasal surgery is a safe and effective treatment for ACTH-producing adenomas. The rate of remission in this study is comparable to those in previous series, and the rate of major postoperative complications is extremely low. Further studies with a larger number of patients and longer follow-ups are required to determine whether this more minimally invasive pure endoscopic approach should become the standard of care for the surgical treatment of Cushing disease.

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Ivo Peto, Hussam Abou-Al-Shaar, and Amir R. Dehdashti

Posterior fossa dural arteriovenous fistulas (dAVFs) are rare vascular malformations. They carry a significant risk of hemorrhage if associated with cortical venous reflux. A 70-year-old man presented with right-sided medullary hemorrhage with pronounced Wallenberg syndrome. Angiography demonstrated right jugular foramen dAVF with direct brainstem venous reflux (Cognard IV). It was fed from multiple branches of the external carotid artery and the vertebral artery, and draining into the ascending pontomesencephalic vein. Primary two-stage transarterial embolization was performed with near-total occlusion of the fistula to prevent it from rebleeding in the acute phase. Because of the patient’s significant neurological deficit, the surgery was deferred to later and if the DAVF showed further progression. Follow-up angiography 8 months later demonstrated obvious recurrence and progression of the fistula from adjacent feeders. In the meantime, the patient had a remarkable recovery from the Wallenberg symptoms. To achieve complete occlusion of the fistula, a right far lateral approach was chosen with complete disconnection of the fistula. Postoperative angiography confirmed complete occlusion of the fistula, and the patient remained intact from the procedure.

The video can be found here: https://youtu.be/DJvpa8G4olc.

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Giorgio Carrabba, Amir R. Dehdashti, and Fred Gentili

Object

Clival lesions pose significant challenges with regard to their surgical management. The expanded endoscopic endonasal (EEE) approach is a promising minimally invasive technique for lesions of the central skull base. The authors' aim in the current paper was to discuss the surgical treatment of clival lesions and to present the technical details, indications, and limitations of the EEE approach. Data from a recent endoscopically treated group will be compared with findings in a previous cohort of patients treated via classic open anterior and lateral approaches.

Methods

Since June 2005, 17 patients with clival lesions underwent surgery via the EEE approach. Suitable candidates were chosen according to lesion characteristics, clinical parameters, and surgical goals. Neurological outcomes, Karnofsky Performance Scale scores, the extent of lesion resection, and complications were evaluated among these patients. Eighteen percent of the patients in the endoscopic group presented with recurrent disease. Another series of 43 patients, who had undergone resection of clival lesions via an anterior (rhinotomy, maxillectomy, microscopic transsphenoidal surgery, or transoral surgery) or lateral (pterional, frontoorbitozygomatic, or combined suprainfratentorial retrosigmoid) approach, was similarly reviewed. Twenty-three of these patients (53%) presented with recurrent disease and thus had undergone prior surgery.

Results

Following the EEE approach, 11 (79%) of 14 patients who had presented with neurological symptoms experienced improvement, and gross-total resection was achieved in 59% of the patients and subtotal removal in 41%. Complications included CSF leakage (24%), tension pneumocephalus (6%), and intracranial hematoma (6%). The patient with the latter complication was the only one who experienced permanent neurological worsening. In the open resection group, neurological worsening occurred in 33% of the patients (14 of 43). Total and grosstotal removals were achieved in 84% of patients and subtotal removal in 14%.

Conclusions

The EEE approach has been shown to be a safe and effective technique for the resection of clival lesions with limited lateral extension. The choice of surgical approach must be tailored according to both patient and tumor characteristics. Although the 2 patient series featured in this paper are not comparable—because of a selection bias—higher rates of neurological morbidity and total and gross-total resections were observed in the open resection group. Given the long survival of some patients, the EEE approach should be favored whenever reasonable.

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Julia R. Schneider, Amrit K. Chiluwal, Mohsen Nouri, Giyarpuram N. Prashant, and Amir R. Dehdashti

OBJECTIVE

The retrosigmoid (RS) approach is a classic route used to access deep-seated brainstem cavernous malformation (CM). The angle of access is limited, so alternatives such as the transpetrosal presigmoid retrolabyrinthine (TPPR) approach have been used to overcome this limitation. Here, the authors evaluated a modification to the RS approach, horizontal fissure dissection by using the RS transhorizontal (RSTH) approach.

METHODS

Relevant clinical parameters were evaluated in 9 patients who underwent resection of lateral pontine CM. Cadaveric dissection was performed to compare the TPPR approach and the RSTH approach.

RESULTS

Five patients underwent the TPPR approach, and 4 underwent the RSTH approach. Dissection of the horizontal fissure allowed for access to the infratrigeminal safe entry zone, with a direct trajectory to the middle cerebellar peduncle similar to that used in TPPR exposure. Operative time was longer in the TPPR group. All patients had a modified Rankin Scale score ≤ 2 at the last follow-up. Cadaveric dissection confirmed increased anteroposterior working angle and middle cerebellar peduncle exposure with the addition of horizontal fissure dissection.

CONCLUSIONS

The RSTH approach leads to a direct lateral path to lateral pontine CM, with similar efficacy and shorter operative time compared with more extensive skull base exposure. The RSTH approach could be considered a valid alternative for resection of selected pontine CM.

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Leodante da Costa, Amir R. Dehdashti, and Karel G. terBrugg E

Object

Spinal cord vascular malformations are rare, fascinating lesions. In this paper, the authors' goal was to demonstrate how these lesions, more specifically spinal cord arteriovenous malformations and dural arteriovenous fistulas, are assessed, classified, and managed at their institution. They also highlight some aspects of classification and management that may be different from the views of others.

Methods

The authors reviewed the 20-year experience at the senior author's institution regarding the management of spinal cord vascular malformations. They discuss the management, surgical and endovascular treatment results, and the classification that resulted from the combined experience of 3 major reference centers.

Results

The accumulated knowledge on embryological and pathophysiological aspects in such a rare disease resulted in a more global, patient-oriented (and not radiologically oriented) approach to spinal cord shunts.

Conclusions

The multiple classifications proposed for spinal cord vascular malformations reflect the continuous advancement of the authors' understanding. They adopt a classification based on new physiological and genetic data that treats these lesions as expressions of more complex disease processes and not simply a morphological target, with direct impact on therapeutic options.

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Amir R. Dehdashti, Bénédict Rilliet, Daniel A. Rufenacht, and Nicolas de Tribolet

Object. This study was designed to determine whether the frequency of shunt-dependent hydrocephalus in patients suffering from aneurysmal subarachnoid hemorrhage (SAH) differs when comparing surgical clip application with endovascular obliteration of ruptured aneurysms.

Methods. In this prospective nonrandomized study, 245 patients with aneurysmal SAH treated using either surgical clip application or endovascular coil embolization were studied at our institution between September 1997 and March 2003. One hundred eighty patients underwent clip application and 65 had coil embolization. In those patients who underwent clip application of anterior circulation aneurysms, the lamina terminalis was systematically fenestrated.

The occurrence of acute, asymptomatic, and shunt-dependent hydrocephalus was analyzed in both treatment groups. A subgroup analysis of patients with good clinical grade (World Federation of Neurosurgical Societies [WFNS] Grades I–III) and better Fisher Grade (1–3) and of patients with Fisher Grade 4 hemorrhage was performed.

Acute hydrocephalus was observed in 19% of surgical cases and 46% of endovascular ones. The occurrence of asymptomatic hydrocephalus was similar in both treatment groups (p = 0.4). Shunt-dependent hydrocephalus occurred in 14% of surgical cases and 19% of endovascular cases. This difference did not reach statistical significance (p = 0.53). Logistic regression models controlling for patient age, WFNS grade, Fisher grade, and acute hydrocephalus in patients with good clinical grade and better Fisher grade revealed no significant difference in the rate of shunt-dependent hydrocephalus in both therapy groups (odds ratio [OR] 0.8, 95% confidence interval [CI] 0.2–2.65). Results of similar models indicated that among patients with intraventricular hemorrhage (IVH), surgical clip application carried a lower risk of shunt-dependent hydrocephalus (OR 0.32, 95% CI 0.14–0.75) compared with that for endovascular embolization.

Conclusions. Shunt-dependent hydrocephalus was comparable in the two treatment groups, even in patients with better clinical and radiological grades on admission. Only patients in the endovascular therapy group who had experienced IVH showed a higher likelihood of shunt-dependent hydrocephalus.