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Charles Y. Liu and Alfredo Quinones-Hinojosa

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Robert G. Grossman, Charles Y. Liu and Amit Verma

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Howard M. Eisenberg, Charles Y. Liu and Oren Sagher

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Gabriel Zada, Eisha Christian, Charles Y. Liu and Steven L. Giannotta

Object

Aneurysms of the anterior communicating artery (ACoA) can be a considerable challenge to treat surgically based on variations in the anatomy and morphological features of the ACoA complex. The fenestrated aneurysm clip can be a simple and practical tool in the operative management of ACoA aneurysms. The goal in this study was to characterize the particular surgical situations in which the use of a fenestrated clip facilitates the clip ligation of ACoA aneurysms.

Methods

The authors present their operative strategy and techniques for the use of fenestrated clips in the treatment of ACoA aneurysms.

Results

One hundred ninety-nine patients underwent surgical clipping of an ACoA aneurysm at the authors' institution between the years 1991 and 2008. Of these patients, fenestrated aneurysm clips were used in 20 cases (10%). The following structures were enclosed in the clip aperture: ipsilateral A2 artery, 12 patients (60%); ipsilateral A1 artery, 4 patients (20%); ipsilateral A1 artery plus recurrent artery of Heubner, 1 patient (5%); ACoA, 1 patient (5%); frontopolar artery, 1 patient (5%); and no structures, 1 patient (5%). Aneurysms approached from the left side more frequently required fenestrated clips than did right-sided aneurysms (80 vs 20%, p = 0.0073). In all cases, patency of the A2 vessels was confirmed on postoperative angiography. In 2 patients, small remnant aneurysm necks were identified on postoperative angiography.

Conclusions

The use of fenestrated aneurysm clips can minimize tedious and potentially dangerous dissection of adherent branch vessels, while maintaining the integrity of structures placed within the clip aperture. The ACoA aneurysms pointing in a superior direction are more likely to require clip fenestration around the A2 vessel, whereas those pointing in an inferior direction are more likely to require clip fenestration around the A1 vessel. The parallel approximation of the fenestrated clip blades makes them especially useful in the treatment of large or giant aneurysms.

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Yvette D. Marquez, Michael Y. Wang and Charles Y. Liu

Over the course of the past few decades, it has become apparent that in contrast to previously held beliefs, the adult central nervous system (CNS) may have the capability of regeneration and repair. This greatly expands the possibilities for the future treatment of CNS disorders, with the potential strategies of treatment targeting the entire scope of neurological diseases. Indeed, there is now ample evidence that stem cells exist in the CNS throughout life, and the progeny of these stem cells may have the ability to assume the functional role of neural cells that have been lost. The existence of stem cells is no longer in dispute. In addition, once transplanted, stem cells have been shown to survive, migrate, and differentiate. Nevertheless, the clinical utility of stem cell therapy for neurorestoration remains elusive. Without question, the control of the behavior of stem cells for therapeutic advantage poses considerable challenges. In this paper, the authors discuss the cellular signaling processes that influence the behavior of stem cells. These signaling processes take place in the microenvironment of the stem cell known as the niche. Also considered are the implications attending the replication and manipulation of elements of the stem cell niche to restore function in the CNS by using stem cell therapy.

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Charles Y. Liu, Brian Lee, Nicholas Boulis and Ali R. Rezai

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Shih Sing Liu, William L. White, Peter C. Johnson and Charles Gauntt

✓ Hemophilic pseudotumor is an uncommon complication among hemophiliacs. Most of these lesions are located in the long bones and the pelvis. The authors describe a case of hemophilic pseudotumor in a patient who presented with symptoms of L-5 radiculopathy and evidence of a destructive lesion on computerized tomography scans. Histologically, the lesion consisted of an organizing hematoma with reactive fibrosis. The diagnosis requires a high index of suspicion. Surgery is recommended for symptomatic patients.

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Daniel J. Hoh, Charles Y. Liu and Michael Y. Wang

Object

Effective methods for fixation of the axis include C1–2 transarticular and C-2 pedicle screw placement. Both techniques pose a risk of vertebral artery (VA) injury in patients with narrow pedicles or an enlarged, high-riding VA. Pars screws at C-2 avoid the pedicle, but can cause VA injury with excessively long screws. Therefore, the authors evaluated various entry points and trajectories to determine ideal pars screw lengths that avoid breaching the transverse foramen.

Methods

Both pars were studied on 50 CT scans (100 total). Various pars lengths were assessed using 2 entry points and 3 trajectories (6 measurements). Entry point A was the superior one-fourth of the lateral mass. Entry point B was 3-mm rostral to the inferior aspect of the lateral mass. Using entry points A and B, Trajectory 1 was the minimum distance to the transverse foramen; Trajectory 2 was the maximum distance to the transverse foramen; and Trajectory 3 was the steepest angle to the pars/C-2 superior facet junction without transverse foramen breach.

Results

The mean patient age was 46 ± 17 years, and 84% of the CT scans reviewed were obtained in men. There was no significant difference in right or left measurements. Entry point B demonstrated greater pars lengths for each trajectory compared with entry point A (p < 0.0001). For both entry points, Trajectory 3 provided the greatest pars length. Using Trajectory 3 with entry point B, 84, 95, and 99% had a pars length that measured ≥ 18, 16, and 14 mm, respectively. Using Trajectory 3 with Entry point A, only 41, 64, and 87% had a pars length that measured ≥ 18, 16, and 14 mm, respectively.

Conclusions

Using an entry point 3-mm rostral to the inferior edge of the lateral mass and a trajectory directed toward the superior facet/pars junction, 99% of partes interarticularis in this study would tolerate a 14-mm screw without breach of the transverse foramen.

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Donald A. Romig, Douglas W. Voth, Chien Liu and Charles E. Brackett

✓ Twenty-five patients with acute head trauma were studied prospectively for appearance of infection during hospitalization in an acute care unit. The study demonstrates: multiple changes in bacterial flora particularly in the respiratory tract, a significant morbidity due to bacterial changes in the respiratory tree, a negligible incidence of bacterial disease due to physiological monitoring procedures, and an inability to correlate changing flora with specific therapeutic or manipulative procedures except tracheostomy. Mortality correlates well with the severity of illness and indirectly with changes in bacterial flora. Despite the frequent isolation of coagulase-positive staphylococci, severity of infectious complications correlate most closely with the acquisition of gram-negative organisms in the respiratory tract.

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Hewitt C. Goodpasture, Donald A. Romig, Douglas W. Voth, Chien Liu and Charles E. Brackett

✓ The authors observed prospectively 28 brain-injured patients, who required respiratory tract intubation, to determine the effect of antibiotic prophylaxis on bacterial flora, the rate of flora change, and the appearance of infection. Antibiotics not only failed to alter the rate of abnormal colonization but were associated with an earlier appearance of Gram-negative bacilli, the organisms that produced the most severe infections. Although more infections occurred in patients initially untreated with antibiotics, these infections were usually mild and caused by organisms susceptible to highly effective and relatively safe drugs. Although highly reproducible as a laboratory determination, the nitroblue tetrazolium dye test score showed no consistent relationship with the presence or absence of bacterial infection. Regular and extensive clinical and laboratory observations, including cultures of the respiratory tract, helped to make the antibiotic administration in these patients specific, appropriate, and reasonable. Broad spectrum antibiotic prophylaxis does not prevent and may enhance the development of severe pulmonary infection in these patients.