Motor Effects of Minimal Traumatic Brain Injury in Mice.

Traumatic brain injury (TBI) is considered to be the leading cause of disability and death among young people. Up to 30% of mTBI patients report motor impairments, such as altered coordination and impaired balance and gait. The objective of the present study was to characterize motor performance and motor learning changes, in order to achieve a more thorough understanding of the possible motor consequences of mTBI in humans. Mice were exposed to traumatic brain injury using the weight-drop model and subsequently subjected to a battery of behavioral motor tests. Immunohistochemistry was conducted in order to evaluate neuronal survival and synaptic connectivity. TBI mice showed a different walking pattern on the Erasmus ladder task, without any significant impairment in motor performance and motor learning. In the running wheels, mTBI mice showed reduced activity during the second dark phase and increased activity during the second light phase compared to the control mice. There was no difference in the sum of wheel revolutions throughout the experiment. On the Cat-Walk paradigm, the mice showed a wider frontal base of support post mTBI. The same mice spent a significantly greater percent of time standing on three paws post mTBI compared with controls. mTBI mice also showed a decrease in the number of neurons in the temporal cortex compared with the control group. In summary, mTBI mice suffered from mild motor impairments, minor changes in the circadian clock, and neuronal damage. A more in-depth examination of the mechanisms by which mTBI compensate for motor deficits is necessary.

Management of osteomas of the paranasal sinuses.

Craniofacial osteomas are benign tumors of the skull base, often involving the paranasal sinuses. The frontal sinus is the most common site of involvement, followed by the ethmoid, maxillary, and sphenoid sinuses, respectively. The growth rate is very slow, and it may take many years for osteomas to become clinically apparent. The origin of these tumors has been ascribed to embryologic tissue maldevelopment, trauma, or infection. The tumors are hard and lobulated with an ivory-like appearance, often mixed with a coarse granular component. The bone is compact or cancellous, with vascular or connective tissue components. The complications of osteoma growth are obstruction of sinus ostia, extension into adjacent bones and the intracranial cavity, and displacement of anatomic structures. Management of uncomplicated sinus osteomas is controversial, since surgery involves serious potential risks. When surgery is performed, these tumors can be successfully managed via endoscopic, open, or combined techniques. This article reviews the clinical findings, diagnostic studies, and treatment of 16 patients with paranasal osteomas. The indications for surgical intervention are discussed.

Partial labyrinthectomy with hearing preservation: an experimental study in guinea pigs.

Recent advances in neurotologic surgery have challenged the traditional belief that violating the labyrinth is incompatible with hearing. Our aim in this study was to define the conditions that result in hearing preservation and hearing loss after surgery on the labyrinth. A guinea pig model was developed. Click-evoked auditory brain stem responses were used to determine hearing thresholds. Animals underwent surgical destruction of part or all of the vestibular labyrinth. Transection and plugging of the lateral semicircular canal resulted in normal hearing. Transection of multiple semicircular canals also resulted in hearing preservation. Intentional suctioning of perilymph from a transected canal led to transient hearing loss with complete recovery. Sequential destruction of the entire lateral semicircular canal resulted in preserved hearing as long as the vestibule was not opened. Wide vestibulotomy resulted in hearing loss. Preliminary histologic studies showed that cochlear hair cells were preserved in most cases. The results of our experiments demonstrate the feasibility of preservation of hearing after partial labyrinthectomy and provide physiologic criteria for developing new operations on the inner ear in human subjects.