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Justin R. Davanzo and Elias Rizk

This is a case report illustrating an overdose of baclofen in a 10-year-old boy due to a likely malfunction of a SynchroMed II pump. This ultimately necessitated a pump replacement. One-year follow-up showed no further incidents of baclofen overdose, with multiple pump refills.

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Justin R. Davanzo, J. Christopher Zacko, Charles S. Specht and Elias B. Rizk

This is the first reported case of an adult presenting with tethering symptoms, limb discrepancy on physical examination, a low-lying spinal cord, and duplicate filum terminale discovered intraoperatively. Intraoperative imaging and pathological analysis of a specimen confirmed the diagnosis of duplicate filum. This is the first reported adult case with duplication of the filum terminale. Release of both fila was necessary in this case to relieve the tethering symptoms.

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Elias Rizk, Mark S. Dias, Joel Verbrugge and Frederick A. Boop

Unusual complications of peritoneal shunts are a well-known occurrence. The authors present 2 cases of intracardiac migration of a distal shunt catheter, summarizing the diagnosis and management of each case. This complication seems to be a rare occurrence; the transgression of the jugular vein leading to intracardiac migration of a shunt catheter has been reported only 6 times previously. The authors highlight the importance of careful and proper placement of the distal peritoneal catheter during the tunneling process, in particular avoiding too deep a penetration of the shunt passer into the neck tissues and too medial a shunt passage near the sternal notch to avoid vascular structures.

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Russell Payne, Zeinab Nasralah, Emily Sieg, Elias B. Rizk, Michael Glantz and Kimberly Harbaugh

OBJECTIVE

A thorough understanding of anatomy is critical for successful carpal tunnel release. Several texts depict the median nerve (MN) as taking a course parallel to the long axis of the forearm (LAF). The authors report on their attempt to formally assess the course of the MN as it travels to the carpal tunnel in the distal wrist and discuss its potential clinical significance.

METHODS

The width of the wrist, the distance from the radial wrist to the MN, and the distance from the distal volar wrist crease to the point where the MN emerges between the flexor carpi radialis (FCR) tendon and the flexor digitorum superficialis (FDS) tendons were recorded during cadaveric dissection of 76 wrist specimens. The presence or absence of palmaris longus was documented. Finally, the angles between the MN and FCR tendon and between the MN and the LAF were measured using ImageJ.

RESULTS

The relative position of the MN at the distal wrist crease, as determined by the ratio of the distance from the MN to the radial wrist divided by wrist width, revealed a mean value of 0.48, indicating that the nerve was usually located just radial to midline. The mean distance between the distal wrist crease and the MN's emergence was 34.6 mm. The mean angle between the MN and the FCR tendon was 14.1°. The angle between the MN and the LAF had a mean value of 8.8° (range 0.0°–32.2°). The nerve was parallel to the LAF in only 10.7% of the studied wrists. Palmaris longus was absent in 14 (18.4%) of the 76 wrists.

CONCLUSIONS

The MN takes an angular approach to the carpal tunnel in the distal wrist in the vast majority of cases. This newly described finding will be useful to both clinicians and anatomists.

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Christoph J. Griessenauer, Elias Rizk, Joseph H. Miller, Philipp Hendrix, R. Shane Tubbs, Mark S. Dias, Kelsie Riemenschneider and Joshua J. Chern

Object

Tectal plate gliomas are generally low-grade astrocytomas with favorable prognosis, and observation of the lesion and management of hydrocephalus remain the mainstay of treatment.

Methods

A cohort of patients with tectal plate gliomas at 2 academic institutions was retrospectively reviewed.

Results

Forty-four patients with a mean age of 10.2 years who harbored tectal plate gliomas were included in the study. The mean clinical and radiological follow-up was 7.6 ± 3.3 years (median 7.9 years, range 1.5–14.7 years) and 6.5 ± 3.1 years (median 6.5 years, range 1.1–14.7 years), respectively. The most frequent intervention was CSF diversion (81.8% of patients) followed by biopsy (11.4%), radiotherapy (4.5%), chemotherapy (4.5%), and resection (2.3%). On MR imaging tectal plate gliomas most commonly showed T1-weighted isointensity (71.4%), T2-weighted hyperintensity (88.1%), and rarely enhanced (19%). The initial mean volume was 1.6 ± 2.2 cm3 and it increased to 2.0 ± 4.4 cm3 (p = 0.628) at the last follow-up. Frontal and occipital horn ratio (FOHR) and third ventricular width statistically decreased over time (p < 0.001 and p < 0.05, respectively).

Conclusions

The authors' results support existing evidence that tectal plate gliomas frequently follow a benign clinical and radiographic course and rarely require any intervention beyond management of associated hydrocephalus.

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Christina Huang, Elias Rizk, Mark Iantosca, Andrea L. Zaenglein, Klaus F. Helm, Arabinda K. Choudhary and Mark S. Dias

An in utero female was found to have a small hemorrhage at the foramen of Monro, hydrocephalus, and what was originally interpreted as a Dandy-Walker variant. At birth she had macrocephaly and numerous cutaneous, multifocal, red-pink blanchable macules. Postnatal MRI demonstrated a hemorrhagic soft-tissue mass involving the upper brainstem, thalamus, and basal ganglia most consistent with in utero complex multifocal intracranial hemorrhage. The skin lesions were thought to be consistent with multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT). The size and location of the hemorrhage precluded operative intervention, although the hydrocephalus was treated with a ventricular shunt. The child continues to have severe developmental delays. Multifocal lymphangioendotheliomatosis with thrombocytopenia is a multifocal vascular disorder most commonly involving the skin and gastrointestinal tract. Intracranial hemorrhages are rare in this context. This case is the third reported instance of MLT with associated intracranial hemorrhage and the only case described in the neurosurgical literature. The authors review the presenting features and pathophysiology of this condition.

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Moksha G. Ranasinghe, Omar Zalatimo, Elias Rizk, Charles S. Specht, G. Timothy Reiter, Robert E. Harbaugh and Jonas Sheehan

Spinal idiopathic hypertrophic pachymeningitis (IHP) is a rare, chronic, nonspecific, granulomatous inflammatory disorder of the dura with unknown etiology. It can cause a localized or diffuse thickening of the dura mater with compression of the spinal canal and possible myelopathic symptoms. The authors report 3 consecutive cases of spinal IHP with a review of the literature. The diagnosis of spinal IHP was based on biopsy and pathological confirmation. Typical MR imaging findings suggestive of spinal IHP were noted in all cases. The clinical course may be marked by deterioration despite conservative therapy and may require surgical intervention to prevent irreversible neurological damage. Therefore, prompt diagnosis and institution of proper treatment is critical.

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Russell Payne, Oliver D. Mrowczynski, Becky Slagle-Webb, Alexandre Bourcier, Christine Mau, Dawit Aregawi, Achuthamangalam B. Madhankumar, Sang Y. Lee, Kimberly Harbaugh, James Connor and Elias B. Rizk

OBJECTIVE

Malignant peripheral nerve sheath tumors (MPNSTs) are soft-tissue sarcomas arising from peripheral nerves. MPNSTs have increased expression of the oncogene aurora kinase A, leading to enhanced cellular proliferation. This makes them extremely aggressive with high potential for metastasis and a devastating prognosis; 5-year survival estimates range from a dismal 15% to 60%. MPNSTs are currently treated with resection (sometimes requiring limb amputation) in combination with chemoradiation, both of which demonstrate limited effectiveness. The authors present the results of immunohistochemical, in vitro, and in vivo analyses of MLN8237 for the treatment of MPNSTs in an orthoxenograft murine model.

METHODS

Immunohistochemistry was performed on tumor sections to confirm the increased expression of aurora kinase A. Cytotoxicity analysis was then performed on an MPNST cell line (STS26T) to assess the efficacy of MLN8237 in vitro. A murine orthoxenograft MPNST model transfected to express luciferase was then developed to assess the efficacy of aurora kinase A inhibition in the treatment of MPNSTs in vivo. Mice with confirmed tumor on in vivo imaging were divided into 3 groups: 1) controls, 2) mice treated with MLN8237, and 3) mice treated with doxorubicin/ifosfamide. Treatment was carried out for 32 days, with imaging performed at weekly intervals until postinjection day 42. Average bioluminescence among groups was compared at weekly intervals using 1-way ANOVA. A survival analysis was performed using Kaplan-Meier curves.

RESULTS

Immunohistochemical analysis showed robust expression of aurora kinase A in tumor cells. Cytotoxicity analysis revealed STS26T susceptibility to MLN8237 in vitro. The group receiving treatment with MLN8237 showed a statistically significant difference in tumor size compared with the control group starting at postinjection day 21 and persisting until the end of the study. The MLN8237 group also showed decreased tumor size compared with the doxorubicin/ifosfamide group at the conclusion of the study (p = 0.036). Survival analysis revealed a significantly increased median survival in the MLN8237 group (83 days) compared with both the control (64 days) and doxorubicin/ifosfamide (67 days) groups. A hazard ratio comparing the 2 treatment groups showed a decreased hazard rate in the MLN8237 group compared with the doxorubicin/ifosfamide group (HR 2.945; p = 0.0134).

CONCLUSIONS

The results of this study demonstrate that MLN8237 is superior to combination treatment with doxorubicin/ifosfamide in a preclinical orthoxenograft murine model. These data have major implications for the future of MPNST research by providing a robust murine model as well as providing evidence that MLN8237 may be an effective treatment for MPNSTs.

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R. Shane Tubbs, Christoph Griessenauer, Elias Rizk, Mohammadali M. Shoja, Stephen F. Pehler, John C. Wellons II and Michael J. Conklin

Injuries to the posterior interosseous nerve (PIN) appear to be very uncommon in children. In this paper, the authors describe a 9-year-old boy with a radial malunion and radial head instability that resulted in PIN compression. Surgical decompression via transection of the overlying supinator muscle with correction of the radial deformity and instability resulted in complete return of PIN function. The clinician should be aware of anterior dislocation of the radial head as a cause of PIN injury. Based on the authors' experience, nerve decompression and correction of the bone deformity result in return of normal PIN function.

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Irene Kim, Betsy Hopson, Inmaculada Aban, Elias B. Rizk, Mark S. Dias, Robin Bowman, Laurie L. Ackerman, Michael D. Partington, Heidi Castillo, Jonathan Castillo, Paula R. Peterson, Jeffrey P. Blount and Brandon G. Rocque

OBJECTIVE

Although the majority of patients with myelomeningocele have hydrocephalus, reported rates of hydrocephalus treatment vary widely. The purpose of this study was to determine the rate of surgical treatment for hydrocephalus in patients with myelomeningocele in the National Spina Bifida Patient Registry (NSBPR). In addition, the authors explored the variation in shunting rates across NSBPR institutions, examined the relationship between hydrocephalus, and the functional lesion level of the myelomeningocele, and evaluated for temporal trends in rates of treated hydrocephalus.

METHODS

The authors queried the NSBPR to identify all patients with myelomeningoceles. Individuals were identified as having been treated for hydrocephalus if they had undergone at least 1 hydrocephalus-related operation. For each participating NSBPR institution, the authors calculated the proportion of patients with treated hydrocephalus who were enrolled at that site. Logistic regression was performed to analyze the relationship between hydrocephalus and the functional lesion level of the myelomeningocele and to compare the rate of treated hydrocephalus in children born before 2005 with those born in 2005 or later.

RESULTS

A total of 4448 patients with myelomeningocele were identified from 26 institutions, of whom 3558 patients (79.99%) had undergone at least 1 hydrocephalus-related operation. The rate of treated hydrocephalus ranged from 72% to 96% among institutions enrolling more than 10 patients. This difference in treatment rates between centers was statistically significant (p < 0.001). Insufficient data were available in the NSBPR to analyze reasons for the different rates of hydrocephalus treatment between sites. Multivariate logistic regression demonstrated that more rostral functional lesion levels were associated with higher rates of treated hydrocephalus (p < 0.001) but demonstrated no significant difference in hydrocephalus treatment rates between children born before versus after 2005.

CONCLUSIONS

The rate of hydrocephalus treatment in patients with myelomeningocele in the NSBPR is 79.99%, which is consistent with the rates in previously published literature. The authors’ data demonstrate a clear association between functional lesion level of the myelomeningocele and the need for hydrocephalus treatment.