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M. Yashar S. Kalani, John E. Wanebo, Nikolay L. Martirosyan, Peter Nakaji, Joseph M. Zabramski, and Robert F. Spetzler

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Sam Safavi-Abbasi, M. Yashar S. Kalani, Ben Frock, Hai Sun, Kaan Yagmurlu, Felix Moron, Laura A. Snyder, Randy J. Hlubek, Joseph M. Zabramski, Peter Nakaji, and Robert F. Spetzler

OBJECTIVE

Fusiform cerebral aneurysms represent a small portion of intracranial aneurysms; differ in natural history, anatomy, and pathology; and can be difficult to treat compared with saccular aneurysms. The purpose of this study was to examine the techniques of treatment of ruptured and unruptured fusiform intracranial aneurysms and patient outcomes.

METHODS

In 45 patients with fusiform aneurysms, the authors retrospectively reviewed the presentation, location, and shape of the aneurysm; the microsurgical technique; the outcome at discharge and last follow-up; and the change in the aneurysm at last angiographic follow-up.

RESULTS

Overall, 48 fusiform aneurysms were treated in 45 patients (18 male, 27 female) with a mean age of 49 years (median 51 years; range 6 months–76 years). Twelve patients (27%) had ruptured aneurysms and 33 (73%) had unruptured aneurysms. The mean aneurysm size was 8.9 mm (range 6–28 mm). The aneurysms were treated by clip reconstruction (n = 22 [46%]), clip-wrapping (n = 18 [38%]), and vascular bypass (n = 8 [17%]). The mean (SD) hospital stay was 19.0 ± 7.4 days for the 12 patients with subarachnoid hemorrhage and 7.0 ± 5.6 days for the 33 patients with unruptured aneurysms. The mean follow-up was 38.7 ± 29.5 months (median 36 months; range 6–96 months). The mean Glasgow Outcome Scale score for the 12 patients with subarachnoid hemorrhage was 3.9; for the 33 patients with unruptured aneurysms, it was 4.8. No rehemorrhages occurred during follow-up. The overall annual risk of recurrence was 2% and that of rehemorrhage was 0%.

CONCLUSIONS

Fusiform and dolichoectatic aneurysms involving the entire vessel wall must be investigated individually. Although some of these aneurysms may be amenable to primary clipping and clip reconstruction, these complex lesions often require alternative microsurgical and endovascular treatment. These techniques can be performed with acceptable morbidity and mortality rates and with low rates of early rebleeding and recurrence.

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Michael R. Levitt, Randall J. Hlubek, Karam Moon, M. Yashar S. Kalani, Peter Nakaji, Kris A. Smith, Andrew S. Little, Kerry Knievel, Jane W. Chan, Cameron G. McDougall, and Felipe C. Albuquerque

OBJECTIVE

Cerebral venous pressure gradient (CVPG) from dural venous sinus stenosis is implicated in headache syndromes such as idiopathic intracranial hypertension (IIH). The incidence of CVPG in headache patients has not been reported.

METHODS

The authors reviewed all cerebral venograms with manometry performed for headache between January 2008 and May 2015. Patient demographics, headache etiology, intracranial pressure (ICP) measurements, and radiographic and manometric results were recorded. CVPG was defined as a difference ≥ 8 mm Hg by venographic manometry.

RESULTS

One hundred sixty-four venograms were performed in 155 patients. There were no procedural complications. Ninety-six procedures (58.5%) were for patients with IIH. The overall incidence of CVPG was 25.6% (42 of 164 procedures): 35.4% (34 of 96 procedures) in IIH patients and 11.8% (8 of 68 procedures) in non-IIH patients. Sixty procedures (36.6%) were performed in patients with preexisting shunts. Seventy-seven patients (49.7%) had procedures preceded by an ICP measurement within 4 weeks of venography, and in 66 (85.7%) of these patients, the ICP had been found to be elevated. CVPG was seen in 8.3% (n = 5) of the procedures in the 60 patients with a preexisting shunt and in 0% (n = 0) of the 11 procedures in the 77 patients with normal ICP (p < 0.001 for both). Noninvasive imaging (MR venography, CT venography) was assessed prior to venography in 112 (68.3%) of 164 cases, and dural venous sinus abnormalities were demonstrated in 73 (65.2%) of these cases; there was a trend toward CVPG (p = 0.07). Multivariate analysis demonstrated an increased likelihood of CVPG in patients with IIH (OR 4.97, 95% CI 1.71–14.47) and a decreased likelihood in patients with a preexisting shunt (OR 0.09, 95% CI 0.02–0.44).

CONCLUSIONS

CVPG is uncommon in IIH patients, rare in those with preexisting shunts, and absent in those with normal ICP.

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Christopher D. Wilson, Sam Safavi-Abbasi, Hai Sun, M. Yashar S. Kalani, Yan D. Zhao, Michael R. Levitt, Ricardo A. Hanel, Eric Sauvageau, Timothy B. Mapstone, Felipe C. Albuquerque, Cameron G. McDougall, Peter Nakaji, and Robert F. Spetzler

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (aSAH) may be complicated by hydrocephalus in 6.5%–67% of cases. Some patients with aSAH develop shunt dependency, which is often managed by ventriculoperitoneal shunt placement. The objectives of this study were to review published risk factors for shunt dependency in patients with aSAH, determine the level of evidence for each factor, and calculate the magnitude of each risk factor to better guide patient management.

METHODS

The authors searched PubMed and MEDLINE databases for Level A and Level B articles published through December 31, 2014, that describe factors affecting shunt dependency after aSAH and performed a systematic review and meta-analysis, stratifying the existing data according to level of evidence.

RESULTS

On the basis of the results of the meta-analysis, risk factors for shunt dependency included high Fisher grade (OR 7.74, 95% CI 4.47–13.41), acute hydrocephalus (OR 5.67, 95% CI 3.96–8.12), in-hospital complications (OR 4.91, 95% CI 2.79–8.64), presence of intraventricular blood (OR 3.93, 95% CI 2.80–5.52), high Hunt and Hess Scale score (OR 3.25, 95% CI 2.51–4.21), rehemorrhage (OR 2.21, 95% CI 1.24–3.95), posterior circulation location of the aneurysm (OR 1.85, 95% CI 1.35–2.53), and age ≥ 60 years (OR 1.81, 95% CI 1.50–2.19). The only risk factor included in the meta-analysis that did not reach statistical significance was female sex (OR 1.13, 95% CI 0.77–1.65).

CONCLUSIONS

The authors identified several risk factors for shunt dependency in aSAH patients that help predict which patients are likely to require a permanent shunt. Although some of these risk factors are not independent of each other, this information assists clinicians in identifying at-risk patients and managing their treatment.

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Kaan Yagmurlu, Sam Safavi-Abbasi, Evgenii Belykh, M. Yashar S. Kalani, Peter Nakaji, Albert L. Rhoton Jr., Robert F. Spetzler, and Mark C. Preul

OBJECTIVE

The aim of this investigation was to modify the mini-pterional and mini-orbitozygomatic (mini-OZ) approaches in order to reduce the amount of tissue traumatization caused and to compare the use of the 2 approaches in the removal of circle of Willis aneurysms based on the authors' clinical experience and quantitative analysis.

METHODS

Three formalin-fixed adult cadaveric heads injected with colored silicone were examined. Surgical freedom and angle of attack of the mini-pterional and mini-OZ approaches were measured at 9 anatomical points, and the measurements were compared. The authors also retrospectively reviewed the cases of 396 patients with ruptured and unruptured single aneurysms in the circle of Willis treated by microsurgical techniques at their institution between January 2006 and November 2014.

RESULTS

A significant difference in surgical freedom was found in favor of the mini-pterional approach for access to the ipsilateral internal carotid artery (ICA) and middle cerebral artery (MCA) bifurcations, the most distal point of the ipsilateral posterior cerebral artery (PCA), and the basilar artery (BA) tip. No statistically significant differences were found between the mini-pterional and mini-OZ approaches for access to the posterior clinoid process, the most distal point of the superior cerebellar artery (SCA), the anterior communicating artery (ACoA), the contralateral ICA bifurcation, and the most distal point of the contralateral MCA. A trend toward increasing surgical freedom was found for the mini-OZ approach to the ACoA and the contralateral ICA bifurcation. The lengths exposed through the mini-OZ approach were longer than those exposed by the mini-pterional approach for the ipsilateral PCA segment (11.5 ± 1.9 mm) between the BA and the most distal point of the P2 segment of the PCA, for the ipsilateral SCA (10.5 ± 1.1 mm) between the BA and the most distal point of the SCA, and for the contralateral anterior cerebral artery (ACA) (21 ± 6.1 mm) between the ICA bifurcation and the most distal point of the A2 segment of the ACA. The exposed length of the contralateral MCA (24.2 ± 8.6 mm) between the contralateral ICA bifurcation and the most distal point of the MCA segment was longer through the mini-pterional approach. The vertical angle of attack (anteroposterior direction) was significantly greater with the mini-pterional approach than with the mini-OZ approach, except in the ACoA and contralateral ICA bifurcation. The horizontal angle of attack (mediolateral direction) was similar with both approaches, except in the ACoA, contralateral ICA bifurcation, and contralateral MCA bifurcation, where the angle was significantly increased in the mini-OZ approach.

CONCLUSIONS

The mini-pterional and mini-OZ approaches, as currently performed in select patients, provide less tissue traumatization (i.e., less temporal muscle manipulation, less brain parenchyma retraction) from the skin to the aneurysm than standard approaches. Anatomical quantitative analysis showed that the mini-OZ approach provides better exposure to the contralateral side for controlling the contralateral parent arteries and multiple aneurysms. The mini-pterional approach has greater surgical freedom (maneuverability) for ipsilateral circle of Willis aneurysms.

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Sam Safavi-Abbasi, Felix Moron, Hai Sun, Mark E. Oppenlander, M. Yashar S. Kalani, Celene B. Mulholland, Joseph M. Zabramski, Peter Nakaji, and Robert F. Spetzler

OBJECTIVE

To address the challenges of microsurgically treating broad-based, frail, and otherwise complex aneurysms that are not amenable to direct clipping, alternative techniques have been developed. One such technique is to use cotton to augment clipping (“cotton-clipping” technique), which is also used to manage intraoperative aneurysm neck rupture, and another is to reinforce unclippable segments or remnants of aneurysm necks with cotton (“cotton-augmentation” technique). This study reviews the natural history of patients with aneurysms treated with cotton-clipping and cotton-augmentation techniques.

METHODS

The authors queried a database consisting of all patients with aneurysms treated at Barrow Neurological Institute in Phoenix, Arizona, between January 1, 2004, and December 31, 2014, to identify cases in which cotton-clipping or cotton-augmentation strategies had been used. Management was categorized as the cotton-clipping technique if cotton was used within the blades of the aneurysm clip and as the cotton-clipping technique if cotton was used to reinforce aneurysms or portions of the aneurysm that were unclippable due to the presence of perforators, atherosclerosis, or residual aneurysms. Data were reviewed to assess patient outcomes and annual rates of aneurysm recurrence or hemorrhage after the initial procedures were performed.

RESULTS

The authors identified 60 aneurysms treated with these techniques in 57 patients (18 patients with ruptured aneurysms and 39 patients with unruptured aneurysms) whose mean age was 53.1 years (median 55 years; range 24–72 years). Twenty-three aneurysms (11 cases of subarachnoid hemorrhage) were treated using cotton-clipping and 37 with cotton-augmentation techniques (7 cases of subarachnoid hemorrhage). In total, 18 patients presented with subarachnoid hemorrhage. The mean Glasgow Outcome Scale (GOS) score at the time of discharge was 4.4. At a mean follow-up of 60.9 ± 35.6 months (median 70 months; range 10–126 months), the mean GOS score at last follow-up was 4.8. The total number of patient follow-up years was 289.4. During the follow-up period, none of the cotton-clipped aneurysms increased in size, changed in configuration, or rebled. None of the patients experienced early rebleeding. The annual hemorrhage rate for aneurysms treated with cotton-augmentation was 0.52% and the recurrence rate was 1.03% per year. For all patients in the study, the overall risk of hemorrhage was 0.35% per year and the annual recurrence rate was 0.69%.

CONCLUSIONS

Cotton-clipping is an effective and durable treatment strategy for intraoperative aneurysm rupture and for management of broad-based aneurysms. Cotton-augmentation can be safely used to manage unclippable or partially clipped intracranial aneurysms and affords protection from early aneurysm re-rupture and a relatively low rate of late rehemorrhage.

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Nikolay L. Martirosyan, Jennifer M. Eschbacher, M. Yashar S. Kalani, Jay D. Turner, Evgenii Belykh, Robert F. Spetzler, Peter Nakaji, and Mark C. Preul

OBJECTIVE

This study evaluated the utility, specificity, and sensitivity of intraoperative confocal laser endomicroscopy (CLE) to provide diagnostic information during resection of human brain tumors.

METHODS

CLE imaging was used in the resection of intracranial neoplasms in 74 consecutive patients (31 male; mean age 47.5 years; sequential 10-month study period). Intraoperative in vivo and ex vivo CLE was performed after intravenous injection of fluorescein sodium (FNa). Tissue samples from CLE imaging–matched areas were acquired for comparison with routine histological analysis (frozen and permanent sections). CLE images were classified as diagnostic or nondiagnostic. The specificities and sensitivities of CLE and frozen sections for gliomas and meningiomas were calculated using permanent histological sections as the standard.

RESULTS

CLE images were obtained for each patient. The mean duration of intraoperative CLE system use was 15.7 minutes (range 3–73 minutes). A total of 20,734 CLE images were correlated with 267 biopsy specimens (mean number of images/biopsy location, in vivo 84, ex vivo 70). CLE images were diagnostic for 45.98% in vivo and 52.97% ex vivo specimens. After initiation of CLE, an average of 14 in vivo images and 7 ex vivo images were acquired before identification of a first diagnostic image. CLE specificity and sensitivity were, respectively, 94% and 91% for gliomas and 93% and 97% for meningiomas.

CONCLUSIONS

CLE with FNa provided intraoperative histological information during brain tumor removal. Specificities and sensitivities of CLE for gliomas and meningiomas were comparable to those for frozen sections. These data suggest that CLE could allow the interactive identification of tumor areas, substantially improving intraoperative decisions during the resection of brain tumors.

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Nikolay L. Martirosyan, M. Yashar S. Kalani, Peter Nakaji, and Robert F. Spetzler

The anterior interhemispheric approach is a workhorse for treatment of lesions in the third ventricle. In this case, we demonstrate the utility of this approach for resecting a complex third ventricular cavernous malformation. We discuss patient positioning, optimal location of the craniotomy, and surgical resection techniques for safe removal of these lesions. We also demonstrate the importance of gravity retraction using the falx to prevent injury to the dominant frontal lobe.

The video can be found here: https://youtu.be/38woc28er7M.

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M. Yashar S. Kalani, Ting Lei, Nikolay L. Martirosyan, Mark E. Oppenlander, Robert F. Spetzler, and Peter Nakaji

The mesial temporal lobe can be approached via a pterional or orbitozygomatic craniotomy, the subtemporal approach, or transcortically. Alternatively, the entire mesial temporal lobe can be accessed using a lateral supracerebellar transtentorial (SCTT) approach. Here we describe the technical nuances of patient positioning, craniotomy, supracerebellar dissection, and tentorial disconnection to traverse the tentorial incisura to arrive at the posterior mesial temporal lobe for a cavernous malformation. The SCTT approach is especially useful for lesions in the dominant temporal lobe where an anterolateral approach may endanger language centers or the vein of Labbé.

The video can be found here: https://youtu.be/D8mIR5yeiVw.

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M. Yashar S. Kalani, Nikolay L. Martirosyan, Peter Nakaji, and Robert F. Spetzler

The supracerebellar infratentorial approach provides access to the dorsal midbrain, pineal region, and tentorial incisura. This approach can be used with the patient in a sitting, prone, park-bench, or supine position. For a patient with a supple neck and favorable anatomy, we prefer the supine position. The ipsilateral shoulder is elevated, the head turned to the contralateral side, the chin is tucked, and the neck extended toward the floor to open the craniocervical angle for added working room. Care must be taken to place the craniotomy laterally to make use of the ascending angle of the tentorium for ease of access to deep-seated lesions.

The video can be found here: https://youtu.be/BZh6ljmE23k.