Detection of third and sixth cranial nerve palsies with a novel method for eye tracking while watching a short film clip.

OBJECT: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Analysis of skeletal mandibular abnormalities associated with cervicofacial lymphatic malformations.

OBJECTIVES/HYPOTHESIS: Many children with cervicofacial lymphatic malformations have facial skeletal abnormalities. This study qualitatively and quantitatively evaluated these bony mandibular abnormalities. STUDY DESIGN: Retrospective chart review. METHODS: Patients with craniofacial lymphatic malformations presenting to a vascular anomalies center during a 2-year period were included. An age-matched control population was found on the Picture Archiving and Communication System database. Three-dimensional reconstructions were created from computed tomography and magnetic resonance imaging. Qualitative observations and quantitative measurements were taken of the gonial angle, mandibular anterior dentoalveolar height, and anterior condylar displacement. RESULTS: There were 23 controls. A total of 21 patients with "beard" distribution malformations were studied; 10 had unilateral and 11 had bilateral disease.Qualitatively, a few patterns emerged: outward ramal flaring, anterior displacement of the mandible, relative ipsilateral facial "hypertrophy," and anterior positioning of the maxilla and orbit. The open-bite deformity was a common finding leading to malocclusion and oral incompetence. Quantitatively, in 67 nondiseased sides, the average gonial angle was 131 degrees (standard deviation [SD] = 6.8), whereas in 32 diseased sides, the average angle was 152 degrees (SD = 14.0, P < 3.8E-09). With half-beard malformations, the diseased side averaged 153.9 and the nondiseased side averaged 140.8 (P = .008). The average condylar displacement was 8.5 mm versus 5.9 mm (diseased vs. nondiseased), and the average mandibular dentoalveolar height to face ratio was 0.37 (control = 0.34). CONCLUSIONS: Cervicofacial lymphatic malformations in the "beard" distribution are associated with significant bony abnormalities leading to both functional and aesthetic sequelae. Our study is the first quantitative analysis of these changes. This is the first step in planning for dentofacial orthopedics, orthodontics, and orthognathic surgery.

A retrospective analysis of pedicle screws in contact with the great vessels.

OBJECT: Pedicle screws placed in the thoracic, lumbar, and sacral spine occasionally come in contact with the aorta, vena cava, or iliac vessels. When such screws are seen on postoperative imaging in an asymptomatic patient, the surgeon must decide whether it is riskier to revise the screw or to observe it. The authors hypothesized that the incidence of screw placement causing perioperative vessel injury is low and, further, that screws placed in contact with major vessels do not always result in vessel injury. METHODS: A retrospective review of the operative records of 182 consecutive patients undergoing thoracic, lumbar, and lumbosacral pedicle screw fusion was performed to determine the frequency of intraoperative vessel injury. Postoperative imaging for 107 patients was available to determine the incidence of screws in contact with major vessels. Charts were examined to determine if any adverse sequelae had resulted from malpositioned screws. Patient outcomes were documented. RESULTS: There were no intraoperative vessel injuries or deaths in 182 consecutive operations. One hundred seven patients with available postoperative films had 680 pedicle screws placed between T-3 and the sacrum during 115 operations. No patient had arterial screw penetration or deformation on postoperative imaging. Thirty-three of the 680 inserted screws were in contact with a major vessel on routine postoperative imaging. The contacted vessels included the aorta (4 cases), the iliac artery (7 cases), and the iliac veins (22 cases). Patients were followed up until death or November 2009, for a mean follow-up of 44 months (median 44 months, range 5-109 months). None of the patients with vessel contact was noted to suffer symptoms or sequelae as a result of vessel contact. Radiographic follow-up as long as 50 months after surgery revealed no detectable vessel abnormality at the contacted site. CONCLUSIONS: Placing pedicle screws in contact with major vessels is a known risk of spinal surgery. The risk of repositioning a screw in contact with a major vessel but causing no symptoms must be weighed against the relative risk of leaving it in place.