✓ Tonsillar descent of the cerebellum in Chiari I malformations is often considered a congenital defect. A patient is presented in whom magnetic resonance (MR) imaging revealed normally positioned cerebellar tonsils; however, 1 year later MR imaging was repeated for evaluation of gait abnormalities and showed descent of the cerebellar tonsils. This case illustrates worsening symptoms with progressive descent of the cerebellar tonsils and suggests that Chiari I malformations can evolve postnatally.
Paul P. Huang and Shlomo Constantini
Omar Tanweer, Akwasi Boah and Paul P. Huang
Patients undergoing placement of an external ventricular drain (EVD) are at increased risk for development of venous thromboembolisms (VTEs). Early chemical prophylaxis has been shown to decrease rates of embolism formation, but the risks for bleeding and the optimal time to initiate prophylaxis have not been clearly defined for this patient population. The authors evaluated the safety and risks for bleeding when chemical prophylaxis for VTEs was started within 24 hours of EVD placement.
To compare rates of hemorrhage among patients who received prophylaxis within 24 hours and those who received it later than 24 hours after admission, the authors conducted an institutional review board–approved retrospective review. Patients were those who had had an EVD placed and postprocedural imaging conducted at Bellevue Hospital, New York, from January 2009 through April 2012. Data collected included demographics, diagnosis, coagulation panel results, time to VTE prophylaxis and imaging, and occurrence of VTEs. The EVD-associated hemorrhages were classified as Grade 0, no hemorrhage; Grade 1, petechial hyperdensity near the drain; Grade 2, hematoma of 1–15 ml; Grade 3, epidural or subdural hematoma greater than 15 ml; or Grade 4, intraventricular hemorrhage or hematoma requiring surgical intervention.
Among 99 patients, 111 EVDs had been placed. Low-dose unfractionated heparin had been given within 24 hours of admission (early prophylaxis) to 56 patients and later than 24 hours after admission (delayed prophylaxis) to 55 patients. There were no statistical differences across all grades (0–4) among those who received early prophylaxis (n = 45, 5, 5, 1, and 0, respectively) and those who received delayed prophylaxis (n = 46, 4, 1, 1, and 3, respectively) (p = 0.731). In the early prophylaxis group, 3 VTEs were discovered among 32 of 56 patients screened for clinically suspected VTEs. In the delayed prophylaxis group, 5 VTEs were discovered among 33 of 55 patients screened for clinically suspected VTEs (p = 0.71).
Hemorrhagic complications did not increase when chemical prophylaxis was started within 24 hours of admission. Also, the incidence of VTEs did not differ between patients in the early and delayed prophylaxis groups. Larger randomized controlled trials are probably needed to assess decreases in VTEs with earlier prophylaxis.
Shaun D. Rodgers, Bryan J. Marascalchi, Russell G. Strom and Paul P. Huang
Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) syndrome is classified under trigeminal autonomic cephalalgias. This rare headache syndrome is infrequently associated with secondary pathologies. In this paper the authors report on a patient with paroxysmal left retroorbital pain with associated autonomic symptoms of ipsilateral conjunctival injection and lacrimation, suggestive of SUNCT syndrome. After failed medical treatment an MRI sequence was obtained in this patient, demonstrating an epidermoid tumor in the left cerebellopontine angle. The patient's symptoms completely resolved after a gross-total resection of the tumor. This case demonstrates the effectiveness of resection as definitive treatment for SUNCT syndrome associated with tumoral compression of the trigeminal nerve. Early MRI studies should be considered in all patients with SUNCT, especially those with atypical signs and symptoms.
Conor Grady, Omar Tanweer, David Zagzag, Jafar J. Jafar, Paul P. Huang and Douglas Kondziolka
Stereotactic radiosurgery is widely used to treat cerebral arteriovenous malformations (AVMs), with the goal of complete angiographic obliteration. A number of case series have challenged the assumption that absence of residual AVM on follow-up angiograms is consistent with elimination of the risk of hemorrhage. The authors describe 3 cases in which patients who had angiographic evidence of AVM occlusion presented with late hemorrhage in the area of their prior lesions. They compare the radiographic, angiographic, and histological features of these patients with those previously described in the literature.
Delayed hemorrhage from the tissue of occluded AVMs has been reported as early as 4 and as late as 11 years after initial stereotactic radiosurgery. In all cases for which data are available, hemorrhage occurred in the area of persistent imaging findings despite negative findings on conventional angiography. The hemorrhagic lesions that were resected demonstrated a number of distinct histological findings.
While rare, delayed hemorrhage from the tissue of occluded AVMs may occur from a number of distinct, angiographically occult postirradiation changes. The hemorrhages in the authors' 3 cases were symptomatic and localized. The correlation of histological and imaging findings in delayed hemorrhage from occluded AVMs is an area requiring further investigation.
Omar Tanweer, Taylor A. Wilson, Stephen P. Kalhorn, John G. Golfinos, Paul P. Huang and Douglas Kondziolka
Physicians are often solicited by patients or colleagues for clinical recommendations they would make for themselves if faced by a clinical situation. The act of making a recommendation can alter the clinical course being taken. The authors sought to understand this dynamic across different neurosurgical scenarios by examining how neurosurgeons value the procedures that they offer.
The authors conducted an online survey using the Congress of Neurological Surgeons listserv in May 2013. Respondents were randomized to answer either as the surgeon or as the patient. Questions encompassed an array of distinct neurosurgical scenarios. Data on practice parameters and experience levels were also collected.
Of the 534 survey responses, 279 responded as the “neurosurgeon” and 255 as the “patient.” For both vestibular schwannoma and arteriovenous malformation management, more respondents chose resection for their patient but radiosurgery for themselves (p = 0.002 and p = 0.001, respectively). Aneurysm coiling was chosen more often than clipping, but those whose practice was ≥ 30% open cerebrovascular neurosurgery were less likely to choose coiling. Overall, neurosurgeons who focus predominantly on tumors were more aggressive in managing the glioma, vestibular schwannoma, arteriovenous malformation, and trauma. Neurosurgeons more than 10 years out of residency were less likely to recommend surgery for management of spinal pain, aneurysm, arteriovenous malformation, and trauma scenarios.
In the majority of cases, altering the role of the surgeon did not change the decision to pursue treatment. In certain clinical scenarios, however, neurosurgeons chose treatment options for themselves that were different from what they would have chosen for (or recommended to) their patients. For the management of vestibular schwannomas, arteriovenous malformations, intracranial aneurysms, and hypertensive hemorrhages, responses favored less invasive interventions when the surgeon was the patient. These findings are likely a result of cognitive biases, previous training, experience, areas of expertise, and personal values.
Marian Wisniewski, Cyril Toker, Paul J. Anderson, Yun P. Huang and Leonard I. Malis
✓ A rare case of benign chondroblastoma of the cervical spine is described, and the differential diagnosis of benign lesions in the spine discussed.
Raqeeb Haque, Teresa J. Wojtasiewicz, Paul R. Gigante, Mark A. Attiah, Brendan Huang, Steven R. Isaacson and Michael B. Sisti
The goal of this article was to show that a combination of facial nerve–sparing microsurgical resection and Gamma Knife surgery (GKS) for expansion of any residual tumor can preserve good facial nerve function in patients with recurrent vestibular schwannoma (VS).
Records of individuals treated by a single surgeon with a facial nerve–sparing technique for a VS between 1998 and 2009 were retrospectively analyzed for tumor recurrence. Of the 383 patients treated for VS, 151 underwent microsurgical resection, and 20 (13.2%) of these patients required postoperative retreatment for a significant expansion of residual tumor after microsurgery. These 20 patients were re-treated with GKS.
The rate of preservation of good facial nerve function (Grade I or II on the House-Brackmann scale) in patients treated with microsurgery for VS was 97%. Both subtotal and gross-total resection had excellent facial nerve preservation rates (97% vs 96%), although subtotal resection carried a higher risk that patients would require retreatment. In patients re-treated with GKS after microsurgery, the rate of facial nerve preservation was 95%.
In patients with tumors that cannot be managed with radiosurgery alone, a facial nerve–sparing resection followed by GKS for any significant regrowth provides excellent facial nerve preservation rates.
Radek Kolecki, Vikalpa Dammavalam, Abdullah Bin Zahid, Molly Hubbard, Osamah Choudhry, Marleen Reyes, ByoungJun Han, Tom Wang, Paraskevi Vivian Papas, Aylin Adem, Emily North, David T. Gilbertson, Douglas Kondziolka, Jason H. Huang, Paul P. Huang and Uzma Samadani
The precise threshold differentiating normal and elevated intracranial pressure (ICP) is variable among individuals. In the context of several pathophysiological conditions, elevated ICP leads to abnormalities in global cerebral functioning and impacts the function of cranial nerves (CNs), either or both of which may contribute to ocular dysmotility. The purpose of this study was to assess the impact of elevated ICP on eye-tracking performed while patients were watching a short film clip.
Awake patients requiring placement of an ICP monitor for clinical purposes underwent eye tracking while watching a 220-second continuously playing video moving around the perimeter of a viewing monitor. Pupil position was recorded at 500 Hz and metrics associated with each eye individually and both eyes together were calculated. Linear regression with generalized estimating equations was performed to test the association of eye-tracking metrics with changes in ICP.
Eye tracking was performed at ICP levels ranging from −3 to 30 mm Hg in 23 patients (12 women, 11 men, mean age 46.8 years) on 55 separate occasions. Eye-tracking measures correlating with CN function linearly decreased with increasing ICP (p < 0.001). Measures for CN VI were most prominently affected. The area under the curve (AUC) for eye-tracking metrics to discriminate between ICP < 12 and ≥ 12 mm Hg was 0.798. To discriminate an ICP < 15 from ≥ 15 mm Hg the AUC was 0.833, and to discriminate ICP < 20 from ≥ 20 mm Hg the AUC was 0.889.
Increasingly elevated ICP was associated with increasingly abnormal eye tracking detected while patients were watching a short film clip. These results suggest that eye tracking may be used as a noninvasive, automatable means to quantitate the physiological impact of elevated ICP, which has clinical application for assessment of shunt malfunction, pseudotumor cerebri, concussion, and prevention of second-impact syndrome.
Rafael De la Garza Ramos, C. Rory Goodwin, Nancy Abu-Bonsrah, Amit Jain, Emily K. Miller, Nicole Huang, Khaled M. Kebaish, Paul D. Sponseller and Daniel M. Sciubba
The aim of this study was to investigate the incidence of and factors associated with complications following idiopathic scoliosis surgery in adolescents.
The Nationwide Inpatient Sample database was used to identify patients 10–18 years of age who had undergone spinal fusion for adolescent idiopathic scoliosis (AIS) from 2002 to 2011. Twenty-three unique in-hospital postoperative complications, including death, were examined. A series of logistic regressions was used to determine if any demographic, comorbid, or surgical parameter was associated with complication development. Results of multiple logistic regression analyses were reported as odds ratios with 95% confidence intervals. All analyses were performed after the application of discharge weights to produce national estimates.
A total of 36,335 patients met the study inclusion criteria, 7.6% of whom (95% CI 6.3%–8.9%) developed at least one in-hospital complication. The 3 most common complications were respiratory failure (3.47%), reintubation (1.27%), and implant related (1.14%). Major complications such as death, pancreatitis, disseminated intravascular coagulation, visual loss, spinal cord injury, cardiac arrest, sepsis, nerve root injury, deep vein thrombosis, pulmonary embolism, shock, malignant hyperthermia, myocardial infarction, and iatrogenic stroke each had an incidence ≤ 0.2%. On multiple logistic regression analysis, an increasing age (OR 0.80) was associated with significantly lower odds of complication development; patients who were male (OR 1.80) or who had anemia (OR 2.10), hypertension (OR 2.51), or hypothyroidism (OR 2.27) or underwent revision procedures (OR 5.55) were at a significantly increased risk for complication development. The rates of postoperative complications for posterior, anterior, and combined approaches were 6.7%, 10.0%, and 19.8%, respectively (p < 0.001). Length of fusion (< 8 vs ≥ 8 levels) was not associated with complication development (p = 0.311).
Analysis of 36,335 patients who had undergone surgery for AIS revealed that younger patients, male patients, patients with a history of anemia, hypertension, or hypothyroidism, as well as those undergoing revision or anterior or combined approaches may have higher rates of postoperative complications. However, the overall complication rate was low (7.6%), and major complications had a rate ≤ 0.2% for each event. These findings suggest that surgery for AIS remains relatively safe, and future prospective investigations may further help to decrease the postoperative morbidity rate.
Uzma Samadani, Sameer Farooq, Robert Ritlop, Floyd Warren, Marleen Reyes, Elizabeth Lamm, Anastasia Alex, Elena Nehrbass, Radek Kolecki, Michael Jureller, Julia Schneider, Agnes Chen, Chen Shi, Neil Mendhiratta, Jason H. Huang, Meng Qian, Roy Kwak, Artem Mikheev, Henry Rusinek, Ajax George, Robert Fergus, Douglas Kondziolka, Paul P. Huang and R. Theodore Smith
Automated eye movement tracking may provide clues to nervous system function at many levels. Spatial calibration of the eye tracking device requires the subject to have relatively intact ocular motility that implies function of cranial nerves (CNs) III (oculomotor), IV (trochlear), and VI (abducent) and their associated nuclei, along with the multiple regions of the brain imparting cognition and volition. The authors have developed a technique for eye tracking that uses temporal rather than spatial calibration, enabling detection of impaired ability to move the pupil relative to normal (neurologically healthy) control volunteers. This work was performed to demonstrate that this technique may detect CN palsies related to brain compression and to provide insight into how the technique may be of value for evaluating neuropathological conditions associated with CN palsy, such as hydrocephalus or acute mass effect.
The authors recorded subjects' eye movements by using an Eyelink 1000 eye tracker sampling at 500 Hz over 200 seconds while the subject viewed a music video playing inside an aperture on a computer monitor. The aperture moved in a rectangular pattern over a fixed time period. This technique was used to assess ocular motility in 157 neurologically healthy control subjects and 12 patients with either clinical CN III or VI palsy confirmed by neuro-ophthalmological examination, or surgically treatable pathological conditions potentially impacting these nerves. The authors compared the ratio of vertical to horizontal eye movement (height/width defined as aspect ratio) in normal and test subjects.
In 157 normal controls, the aspect ratio (height/width) for the left eye had a mean value ± SD of 1.0117 ± 0.0706. For the right eye, the aspect ratio had a mean of 1.0077 ± 0.0679 in these 157 subjects. There was no difference between sexes or ages. A patient with known CN VI palsy had a significantly increased aspect ratio (1.39), whereas 2 patients with known CN III palsy had significantly decreased ratios of 0.19 and 0.06, respectively. Three patients with surgically treatable pathological conditions impacting CN VI, such as infratentorial mass effect or hydrocephalus, had significantly increased ratios (1.84, 1.44, and 1.34, respectively) relative to normal controls, and 6 patients with supratentorial mass effect had significantly decreased ratios (0.27, 0.53, 0.62, 0.45, 0.49, and 0.41, respectively). These alterations in eye tracking all reverted to normal ranges after surgical treatment of underlying pathological conditions in these 9 neurosurgical cases.
This proof of concept series of cases suggests that the use of eye tracking to detect CN palsy while the patient watches television or its equivalent represents a new capacity for this technology. It may provide a new tool for the assessment of multiple CNS functions that can potentially be useful in the assessment of awake patients with elevated intracranial pressure from hydrocephalus or trauma.