Nicholas C. Bambakidis
Stereotactic radiosurgery for arteriovenous malformations
Nicholas C. Bambakidis and Warren R. Selman
Nicholas C. Bambakidis, Simon S. Lo and Warren R. Selman
Yifei Duan, Carlito Lagman, Raleigh Ems and Nicholas C. Bambakidis
The exact pathophysiological mechanisms underlying cerebral aneurysm formation remain unclear. Asymmetrical local vascular geometry may play a role in aneurysm formation and progression. The object of this study was to investigate the association between the geometric asymmetry of the middle cerebral artery (MCA) and the presence of MCA aneurysms and associated high-risk features.
Using a retrospective case-control study design, the authors examined MCA anatomy in all patients who had been diagnosed with an MCA aneurysm in the period from 2008 to 2017 at the University Hospitals Cleveland Medical Center. Geometric features of the MCA ipsilateral to MCA aneurysms were compared with those of the unaffected contralateral side (secondary control group). Then, MCA geometry was compared between patients with MCA aneurysms and patients who had undergone CTA for suspected vascular pathology but were ultimately found to have normal intracranial vasculature (primary control group). Parent vessel and aneurysm morphological parameters were measured, calculated, and compared between case and control groups. Associations between geometric parameters and high-risk aneurysm features were identified.
The authors included 247 patients (158 cases and 89 controls) in the study. The aneurysm study group consisted of significantly more women and smokers than the primary control group. Patients with MCA bifurcation aneurysms had lower parent artery inflow angles (p = 0.01), lower parent artery tortuosity (p < 0.01), longer parent artery total length (p = 0.03), and a significantly greater length difference between ipsilateral and contralateral prebifurcation MCAs (p < 0.01) than those in primary controls. Type 2 MCA aneurysms (n = 89) were more likely to be associated with dome irregularity or a daughter sac and were more likely to have a higher cumulative total of high-risk features than type 1 MCA aneurysms (n = 69).
Data in this study demonstrated that a greater degree of parent artery asymmetry for MCA aneurysms is associated with high-risk features. The authors also found that the presence of a long and less tortuous parent artery upstream of an MCA aneurysm is a common phenotype that is associated with a higher risk profile. The aneurysm parameters are easily measurable and are novel radiographic biomarkers for aneurysm risk assessment.
Nicholas C. Bambakidis and Warren R. Selman
Sunil Manjila, Mark Weidenbecher, Maroun T. Semaan, Cliff A. Megerian and Nicholas C. Bambakidis
Several prophylactic surgical methods have been tried to prevent CSF leakage after translabyrinthine resection of acoustic neuroma (TLAN). The authors report an improvised technique for multilayer watertight closure using titanium mesh–hydroxyapatite cement (HAC) cranioplasty in addition to dural substitute and abdominal fat graft after TLAN.
The study was limited to 42 patients who underwent TLAN at University Hospitals Case Medical Center using this new technique from 2006 to 2012. Systematic closure of the surgical wound in layers using temporalis fascia, dural substitute, dural sealant, adipose graft, titanium mesh, and then HAC was performed in each case. Temporalis muscle and eustachian tube obliteration were not used. The main variables studied were patient age, tumor size, tumor location, cosmetic outcome, length of hospitalization, and the incidence of CSF leak, pseudomeningocele, and infection.
Excellent cosmetic outcome was achieved in all patients. There were no cases of postoperative CSF rhinorrhea, incisional CSF leak, or meningitis. Cosmetic results were comparable to those achieved using HAC alone. This cost-effective technique used only a third of the HAC required for traditional closure in which the entire mastoid defect is filled with cement, predisposing to infection. Postoperative CT and MRI showed excellent bony contouring and dural reconstitution, respectively.
The authors report on successful use of titanium mesh–HAC cranioplasty in preventing postoperative CSF leak after TLAN in all cases in their series. The titanium mesh provides a well-defined anatomical dissection plane that would make reoperation easier than working through scarred soft tissue. The mesh bolsters the fat graft and keeps HAC out of direct contact with mastoid air cells, thereby reducing the risk of infection. The cement cranioplasty does not preclude subsequent implantation of a bone-anchored hearing aid.
Nicholas C. Bambakidis and Warren R. Selman
Andreea Seicean, Nima Alan, Sinziana Seicean, Duncan Neuhauser, Warren R. Selman and Nicholas C. Bambakidis
Preoperative anemia may be treated with a blood transfusion. Both are associated with adverse outcomes in various surgical procedures, but this has not been clearly elucidated in surgery for cerebral aneurysms. In this study the authors assessed the association of preoperative anemia and perioperative blood transfusion, separately, on 30-day morbidity and mortality in patients undergoing open surgery for ruptured and unruptured intracranial aneurysms.
The authors identified 668 cases (including 400 unruptured and 268 unruptured intracranial aneurysms) of open surgery for treatment of intracranial aneurysms in the 2006–2012 National Surgical Quality Improvement Program, a validated and reproducible prospective clinical database. Anemia was defined as a hematocrit level less than 39% in males and less than 36% in females. Perioperative transfusion was defined as at least 1 unit of packed or whole red blood cells given at any point between the start of surgery to 72 hours postoperatively. The authors separately compared surgical outcome between patients with (n = 198) versus without (n = 470) anemia, and those who underwent (n = 78) versus those who did not receive (n = 521) a transfusion, using a 1:1 match on propensity score.
In the matched cohorts, all observed covariates were comparable between anemic (n = 147) versus nonanemic (n = 147) and between transfused (n = 67) versus nontransfused patients (n = 67). Anemia was independently associated with prolonged hospital length of stay (LOS; odds ratio [OR] 2.5, 95% confidence interval [CI] 1.4–4.5), perioperative complications (OR 1.9, 95% CI 1.1–3.1), and return to the operating room (OR 2.1, 95% CI 1.1–4.5). Transfusion was also independently associated with perioperative complications (OR 2.4, 95% CI 1.1–5.3).
Preoperative anemia and transfusion are each independent risk factors for perioperative complications in patients undergoing surgery for cerebral aneurysms. Perioperative anemia is also associated with prolonged hospital LOS and 30-day return to the operating room.
Sam Safavi-Abbasi, Joseph M. Zabramski, Pushpa Deshmukh, Cassius V. Reis, Nicholas C. Bambakidis, Nicholas Theodore, Neil R. Crawford, Robert F. Spetzler and Mark C. Preul
The authors quantitatively assessed the effects of balloon inflation as a model of tumor compression on the brainstem, cranial nerves, and clivus by measuring the working area, angle of attack, and brain shift associated with the retrosigmoid approach.
Six silicone-injected cadaveric heads were dissected bilaterally via the retrosigmoid approach. Quantitative data were generated, including key anatomical points on the skull base and brainstem. All parameters were measured before and after inflation of a balloon catheter (inflation volume 4.8 ml, diameter 20 mm) intended to mimic tumor compression.
Balloon inflation significantly shifted (p < 0.001) the brainstem and cranial nerve foramina (mean [± standard deviation] displacement of upper brainstem, 10.2 ± 3.7 mm; trigeminal nerve exit, 6.99 ± 2.38 mm; facial nerve exit, 9.52 ± 4.13 mm; and lower brainstem, 13.63 ± 8.45 mm). The area of exposure at the petroclivus was significantly greater with balloon inflation than without (change, 316.26 ± 166.75 mm2; p < 0.0001). Before and after balloon inflation, there was no significant difference in the angles of attack at the origin of the trigeminal nerve (p > 0.5).
This study adds an experimental component to the emerging field of quantitative neurosurgical anatomy. Balloon inflation can be used to model the effects of a mass lesion. The tumor simulation created “natural” retraction and an opening toward the upper clivus. The findings may be helpful in selecting a surgical approach to increase the working space for resection of certain extraaxial tumors.
Nicholas C. Bambakidis, Mary Petrullis, Kui Xu, Brian Rothstein, Ioannis Karampelas, Youzhi Kuang, Warren R. Selman, Joseph C. LaManna and Robert H. Miller
Sonic hedgehog (Shh) is a glycoprotein molecule that has been shown to be associated with the proliferative capacity of endogenous neural precursor cells during embryonic development. It has also been shown to regulate the proliferative capacity of neural stem cells in the adult subventricular zone (SVZ), which are also upregulated in animal models of ischemic stroke. In the present study, the effects of exogenous administration of intrathecal Shh protein were examined in the setting of a rodent model of ischemic stroke, with particular attention given to endogenous neural stem cell proliferation and migration as well as inducible differences in behavioral recovery.
A rodent model of ischemic stroke was created using the intraluminal suture method of reversible middle cerebral artery occlusion. Animals were treated with intrathecal administration of Shh protein at 24 hours after the onset of the stroke. Behavioral testing was performed, and the animals were killed for measurements of infarct volume 7 days after stroke. Immunohistochemical staining was performed and measurements of cellular proliferation were obtained, with a focus on the proportion and distribution of neural progenitor cells in the SVZ. These values were compared across experimental groups.
Treatment with intrathecal Shh protein resulted in significant improvement in behavioral function compared with the control group, with a significant reduction of ischemic tissue in the cerebral hemisphere. An increase of nestin immunoreactive cells was observed along the SVZ.
Intrathecal Shh agonist at doses that upregulate spinal cord GLI1 transcription increases the population of neural precursor cells after spinal cord injury in adult rats. Intrathecal administration of Shh protein appears to have a neuroprotective effect in animal models of ischemic stroke and is associated with improved behavioral recovery, which may be related to its effects on neurogenesis in the SVZ and could be associated with improved functional recovery.