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Rachid Assina, Christina E. Sarris and Antonios Mammis

Both the history of headache and the practice of craniotomy can be traced to antiquity. From ancient times through the present day, numerous civilizations and scholars have performed craniotomy in attempts to treat headache. Today, surgical intervention for headache management is becoming increasingly more common due to improved technology and greater understanding of headache. By tracing the evolution of the understanding of headache alongside the practice of craniotomy, investigators can better evaluate the mechanisms of headache and the therapeutic treatments used today.

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Rachid Assina, Neil J. Majmundar, Yehuda Herschman and Robert F. Heary

Extreme lateral interbody fusion (XLIF) has gained popularity among spine surgeons for treating multiple conditions of the lumbar spine. In contrast to the anterior lumbar interbody fusion (ALIF) approach, the minimally invasive XLIF approach affords wide access to the lumbar disc space without an access surgeon and causes minimal tissue disruption. The XLIF approach offers many advantages over other lumbar spine approaches, with a reportedly low complication profile. The authors describe the first fatality reported in the literature following an XLIF approach. They describe the case of a 50-year-old woman who suffered a fatal intraoperative injury to the great vessels during a lateral transpsoas approach to the L4–5 disc space.

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Pinakin R. Jethwa, Jason H. Lee, Rachid Assina, Irwin A. Keller and Shabbar F. Danish

Supratentorial primitive neuroectodermal tumors (PNETs) are rare tumors that carry a poorer prognosis than those arising from the infratentorial compartment (such as medulloblastoma). The overall prognosis for these patients depends on several factors including the extent of resection, age at diagnosis, CSF dissemination, and site in the supratentorial space. The authors present the first case of a patient with a newly diagnosed supratentorial PNET in which cytoreduction was achieved with MR-guided laser-induced thermal therapy. A 10-year-old girl presented with left-sided facial weakness and a large right thalamic mass extending into the right midbrain. The diagnosis of supratentorial PNET was made after stereotactic biopsy. Therapeutic options for this lesion were limited because of the risks of postoperative neurological deficits with resection. The patient underwent MR-guided laser-induced thermal ablation of her tumor. Under real-time MR thermometry, thermal energy was delivered to the tumor at a core temperature of 90°C for a total of 960 seconds. The patient underwent follow-up MR imaging at regular intervals to evaluate the tumor response to the thermal ablation procedure. Initial postoperative scans showed an increase in the size of the lesion as well as the amount of the associated edema. Both the size of the lesion and the edema stabilized by 1 week and then decreased below preablation levels at the 3-month postsurgical follow-up. There was a slight increase in the size of the lesion and associated edema at the 6-month follow-up scan, presumably due to concomitant radiation she received as part of her postoperative care. The patient tolerated the procedure well and has had resolution of her symptoms since surgery. Further study is needed to assess the role of laser-induced thermal therapy for the treatment of intracranial tumors. As such, it is a promising tool in the neurosurgical armamentarium. Postoperative imaging has shown no evidence of definitive recurrence at the 6-month follow-up period, but longer-term follow-up is required to assess for late recurrence.

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Rachid Assina, Sebastian Rubino, Christina E. Sarris, Chirag D. Gandhi and Charles J. Prestigiacomo

Early neurosurgical procedures dealt mainly with treatment of head trauma, especially skull fractures. Since the early medical writings by Hippocrates, a great deal of respect was given to the dura mater, and many other surgeons warned against violating the dura. It was not until the 19th century that neurosurgeons started venturing beneath the dura, deep into the brain parenchyma. With this advancement, brain retraction became an essential component of intracranial surgery. Over the years brain retractors have been created pragmatically to provide better visualization, increased articulations and degrees of freedom, greater stability, less brain retraction injury, and less user effort. Brain retractors have evolved from simple handheld retractors to intricate brain-retraction systems with hand-rest stabilizers. This paper will focus on the history of brain retractors, the different types of retractors, and the progression from one form to another.

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Lana D. Christiano, Rachid Assina and Ira M. Goldstein

Ossification of the ligamentum flavum (OLF) is a disease of ectopic bone formation within the ligamentum flavum, which may result in mass effect and neurological compromise. The low thoracic region is the most common region of occurrence, and this is followed by the cervical, then lumbar, spine. The prevalence of OLF is significantly higher in the Japanese population compared with other nationalities and has a male preponderance. Ossification of the ligamentum flavum has been reported in association with the more common ligamentous pathological entities—ossification of the posterior longitudinal ligament and diffuse idiopathic skeletal hyperostosis. These latter two conditions have been linked to several metabolic processes, and a possible genetic basis has been hypothesized. Here, the authors present a unique case of OLF of the cervical spine in a patient with idiopathic hypercalcemia.

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Tejas Sankar, Rachid Assina, John P. Karis, Nicholas Theodore and Mark C. Preul

✓Mannitol is widely considered the hyperosmolar therapy of choice in routine neurosurgical practice for the reduction of intracranial pressure (ICP). The authors present a unique case of a patient with a large meningioma treated with mannitol, in which mannitol accumulation within the tumor and its surrounding parenchyma was shown using in vivo magnetic resonance spectroscopy (MRS). This rare appearance of mannitol on MRS was characterized by a wide-based peak at 3.8 ppm, which remained detectable several hours after the last dose. These findings provide the first in vivo evidence in support of the prevailing theory that mannitol leakage into the peritumoral edematous region may contribute to rebound increases in ICP and suggest that this phenomenon has the potential to occur in extraaxial tumors. Judicious use of mannitol in the setting of elevated ICP due to tumor may be indicated to avoid potentially deleterious side effects caused by its accumulation.

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Vincent Dodson, Neil Majmundar, Vanessa Swantic and Rachid Assina

OBJECTIVE

The use of vancomycin powder in spine surgery for prophylaxis against surgical site infections (SSIs) is well debated in the literature, with the majority of studies demonstrating improvement and some studies demonstrating no significant reduction in infection rate. It is well known in certain populations that vancomycin powder reduces the general rate of infection, but its effects on reducing the rate of infection due to gram-negative pathogens are not well reviewed. The goal of this paper was to review studies that investigated the efficacy of vancomycin powder as a prophylactic agent against SSI and demonstrate whether the rate of infections by gram-negative pathogens is impacted.

METHODS

An electronic search of the published literature was performed using PubMed and Google Scholar in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A variety of combinations of the search terms “vancomycin powder,” “infection,” “spine,” “gram-negative,” “prophylaxis,” and “surgical site” was used. Inclusion criteria were studies that 1) described an experimental group that received intraoperative intrawound vancomycin powder; 2) included adequately controlled groups that did not receive intraoperative intrawound vancomycin powder; 3) included the number of patients in both the experimental and control groups who developed infection after their spine surgery; and 4) identified the pathogen-causing infection. Studies not directly related to this review’s investigation were excluded from the initial screen. Among the studies that met the criteria of the initial screen, additional reasons for exclusion from the systematic review included lack of a control group, unspecified size of control groups, and inconsistent use of vancomycin powder in the experimental group.

RESULTS

This systematic review includes 21 studies with control groups. Vancomycin powder significantly reduced the relative risk of developing an SSI (RR 0.55, 95% CI 0.45–0.67, p < 0.0001). In addition, the use of vancomycin powder did not significantly increase the risk of infection by gram-negative pathogens (RR 1.11, 95% CI 0.66–1.86, p = 0.701).

CONCLUSIONS

The results of this systematic review suggest that intrawound vancomycin powder is protective against SSI. It is less clear if this treatment increases the risk of gram-negative infection. Further studies are required to investigate whether rates of infection due to gram-negative pathogens are affected by the use of vancomycin powder.

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Eric M. Horn, Nicholas Theodore, Rachid Assina, Robert F. Spetzler, Volker K. H. Sonntag and Mark C. Preul

Object

Venous stasis and intrathecal hypertension are believed to play a significant role in the hypoperfusion present in the spinal cord following injury. Lowering the intrathecal pressure via cerebrospinal fluid (CSF) drainage has been effective in treating spinal cord ischemia during aorta surgery. The purpose of the present study was to determine whether CSF drainage increases spinal cord perfusion and improves outcome after spinal injury in an animal model.

Methods

Anesthetized adult rabbits were subjected to a severe contusion spinal cord injury (SCI). Cerebrospinal fluid was then drained via a catheter to lower the intrathecal pressure by 10 mm Hg. Tissue perfusion was assessed at the site of injury, and values obtained before and after CSF drainage were compared. Two other cohorts of animals were subjected to SCI: 1 group subsequently underwent CSF drainage and the other did not. Results of histological analysis, motor evoked potential and motor function testing were compared between the 2 cohorts at 4 weeks postinjury.

Results

Cerebrospinal fluid drainage led to no significant improvement in spinal cord tissue perfusion. Four weeks after injury, the animals that underwent CSF drainage demonstrated significantly smaller areas of tissue damage at the injury site. There were no differences in motor evoked potentials or motor score outcomes at 4 weeks postinjury.

Conclusions

Cerebrospinal fluid drainage effectively lowers intrathecal pressure and decreases the amount of tissue damage in an animal model of spinal cord injury. Further studies are needed to determine whether different draining regimens can improve motor or electrophysiological outcomes.

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Neil Majmundar, Purvee D. Patel, Vincent Dodson, Ashley Tran, Ira Goldstein and Rachid Assina

OBJECTIVE

Although parasitic infections are endemic to parts of the developing world and are more common in areas with developing economies and poor sanitary conditions, rare cases may occur in developed regions of the world.

METHODS

Articles eligible for the authors’ literature review were initially searched using PubMed with the phrases “parasitic infections” and “spine.” After the authors developed a list of parasites associated with spinal cord infections from the initial search, they expanded it to include individual diagnoses, using search terms including “neurocysticercosis,” “schistosomiasis,” “echinococcosis,” and “toxoplasmosis.”

RESULTS

Two recent cases of parasitic spinal infections from the authors’ institution are included.

CONCLUSIONS

Key findings on imaging modalities, laboratory studies suggestive of parasitic infection, and most importantly a thorough patient history are required to correctly diagnose parasitic spinal infections.

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Rachid Assina, Tejas Sankar, Nicholas Theodore, Sam P. Javedan, Alan R. Gibson, Kris M. Horn, Michael Berens, Volker K. H. Sonntag and Mark C. Preul

Object

Axonal regeneration may be hindered following spinal cord injury (SCI) by a limited immune response and insufficient macrophage recruitment. This limitation has been partially surmounted in small-mammal models of SCI by implanting activated autologous macrophages (AAMs). The authors sought to replicate these results in a canine model of partial SCI.

Methods

Six dogs underwent left T-13 spinal cord hemisection. The AAMs were implanted at both ends of the lesion in 4 dogs, and 2 other dogs received sham implantations of cell media. Cortical motor evoked potentials (MEPs) were used to assess electrophysiological recovery. Functional motor recovery was assessed with a modified Tarlov Scale. After 9 months, animals were injected with wheat germ agglutinin–horseradish peroxidase at L-2 and killed for histological assessment.

Results

Three of the 4 dogs that received AAM implants and 1 of the 2 negative control dogs showed clear recovery of MEP response. Behavioral assessment showed no difference in motor function between the AAM-treated and control groups. Histological investigation with an axonal retrograde tracer showed neither local fiber crossing nor significant uptake in the contralateral red nucleus in both implanted and negative control groups.

Conclusions

In a large-animal model of partial SCI treated with implanted AAMs, the authors saw no morphological or histological evidence of axonal regeneration. Although they observed partial electrophysiological and functional motor recovery in all dogs, this recovery was not enhanced in animals treated with implanted AAMs. Furthermore, there was no morphological or histological evidence of axonal regeneration in animals with implants that accounted for the observed recovery. The explanation for this finding is probably multifactorial, but the authors believe that the AAM implantation does not produce axonal regeneration, and therefore is a technology that requires further investigation before it can be clinically relied on to ameliorate SCI.