bluuebunny/crossref_metadata_2025 huggingface dataset:
Flexible rods and the case for dynamic stabilization
Authors: Highsmith Jason M. , Tumialán Luis M. , Rodts Gerald E.
Published: January 2008

✓The widespread use of instrumentation in the lumbar spine has led to high rates of fusion. This has been accompanied by a marked rise in adjacent-segment disease, which is considered to be an increasingly common and significant consequence of lumbar or lumbosacral fusion. Numerous biomechanical studies have demonstrated that segments fused with rigid metallic fixation lead to significant amounts of supraphysiological stress on adjacent discs and facets. The resultant disc degeneration and/or stenosis may require further surgical intervention and extension of the fusion to address symptomatic adjacent-segment disease.

Recently, dynamic stabilization implants and disc arthroplasty have been introduced as an alternative to rigid fixation. The scope of spinal disease that can be treated with this novel technology, however, remains limited, and these treatments may not apply to patients who still require rigid stabilization and arthrodesis.

In the spectrum between rigid metallic fixation and motion-preserving arthroplasty is a semirigid type of stabilization in which a construct is used that more closely mirrors the modulus of elasticity of natural bone. After either inter-body or posterolateral arthrodesis is achieved, the fused segments will not generate the same adjacent-level forces believed to be the cause of adjacent-segment disease. Although this form of arthrodesis does not completely prevent adjacent-segment disease, the dynamic component of this stabilization technique may minimize its occurrence.

The authors report their initial experience with the use of posterior dynamic stabilization in which polyetheretherketone rods were used for a posterior construct. The biomechanics of dynamic stabilization are discussed, clinical indications are reviewed, and case studies for its application are presented.
Use of computed tomography–single-photon emission computed tomography fusion for diagnosing painful facet arthropathy
Authors: McDonald Matthew , Cooper Robert , Wang Michael Y.
Published: January 2008

✓Facet disease is believed to play a major role in axial low-back pain and may prove in the future to be an important indication for posterior dynamic stabilization. However, the lack of good diagnostic tests and imaging methods for identifying this condition have made this entity obscure. Although single-photon emission computed tomography (SPECT) imaging is a highly sensitive and specific test, the images frequently lack adequate resolution, whereas computed tomography (CT) provides excellent resolution but lacks specificity.

Thirty-seven patients with back pain clinically attributable to facet disease underwent CT–SPECT fusion imaging of the lumbar spine. The SPECT images were obtained using a dual-head gamma camera equipped with VXGP high-resolution collimators using a 20% energy window centered at 140 keV and a 360° rotation totaling 128 projections at 16 seconds each. Transaxial CT images were transferred in the Digital Imaging and Communications in Medicine format to provide proper image overlay in the axial, sagittal, and coronal planes. Scanning for both modalities was performed using standard patient positioning. Patients with concordant images and symptoms then underwent joint injection and/or rhizotomy, which was performed by an independent physician.

Image fusion was successfully performed in all patients, and the image quality allowed definitive localization of the “hot” lesion in all cases, in contrast to conventional high-resolution SPECT scanning, which often led to problems differentiating L4/5 and L5/S1. In patients with solitary lesions, injection led to definitive pain resolution, even if temporary, in all cases with anesthetic blockade.

The CT–SPECT scanning modality combines the virtues of functional and anatomical imaging, aiding the clinician in making the diagnosis of painful facet arthropathy. This modality may prove useful for the selection of patients who are candidates for posterior dynamic stabilization.
Appropriate selection of patients with lumbar spinal stenosis for interspinous process decompression with the X STOP device
Authors: Lauryssen Carl
Published: January 2008

✓With the aging of the population, the number of patients suffering from progressive lumbar spinal stenosis with symptomatic neurogenic intermittent claudication is projected to increase. Unfortunately, these patients are limited to a choice between nonsurgical conservative care and more invasive decompressive surgical procedures such as laminectomy with or without fusion. The X STOP interspinous process decompression system is a commercially available device that provides a minimally invasive alternative treatment, an intermediate option within the continuum of care for these patients. The X STOP is appropriate for patients with moderately severe functional impairment whose symptoms are exacerbated in extension and relieved in flexion. Implanted between the spinous processes without disrupting the normal anatomical structures, the X STOP limits narrowing of the spinal canal and neural foramina by reducing extension at the symptomatic level(s). In this report the author details the approved indications for use of the X STOP and discusses several illustrative cases.
Arachnoid cysts: spontaneous resolution distinct from traumatic rupture
Authors: Bristol Ruth E. , Albuquerque Felipe C. , McDougall Cameron , Spetzler Robert F.
Published: January 2008

✓Although many arachnoid cysts are discovered incidentally and require no intervention, a small subset has been known to rupture. Note that rupture can occur either spontaneously or in association with trauma. Based on a review of the literature on ruptured arachnoid cysts, it appears that patients with middle fossa cysts are more likely to experience symptomatic traumatic rupture than those with cysts in other locations. Middle fossa cysts are more commonly associated with hemispheric subdural collections and hematomas than are any other cysts. The authors report on two representative cases illustrating the distinct presentation, imaging characteristics, and management of these cysts.
Association between an arachnoid cyst and intracranial aneurysms misdiagnosed as a cystic tumor with a mural nodule
Authors: Chhabra Vaninder S. , Zhang Jonathan , Olson Jeffery J.
Published: January 2008

✓The authors report on a 63-year-old man initially admitted to an outside hospital for altered mental status and respiratory distress. A head computed tomography scan disclosed a right frontal cystic mass, suspected to be a neoplasm. An open biopsy was performed at an outside institution, and on visualization of the cyst, an aneurysm was found incidentally. Postoperatively, an angiogram and magnetic resonance image confirmed the presence of a distal right M1 segment aneurysm. The patient was transferred to our institution where, in addition to the middle cerebral artery lesion, a right anterior choroidal artery aneurysm was found intraoperatively; the necks of both aneurysms were clipped successfully. A review of the literature revealed 14 additional cases of intracranial aneurysms associated with arachnoid cysts. Data in the present report highlight the importance of considering an intracystic aneurysm in the differential diagnosis when reviewing cases that involve a cystic mass with a mural nodule. The authors provide a comprehensive summary of documented cases of aneurysms associated with arachnoid cysts. In addition, they include a discussion of prevailing thoughts on the origin and evolution of arachnoid cysts.
Neuroendoscopic management of interhemispheric cysts in children
Authors: Cinalli Giuseppe , Peretta Paola , Spennato Pietro , Savarese Luciano , Varone Antonio , Vedova Paola , Grimaldi Gianpina , Ragazzi Paola , Ruggiero Claudio , Cianciulli Emilio , Maggi Giuseppe
Published: January 2008

Object

Interhemispheric arachnoid cysts are very rare, and they are often associated with complex brain malformations such as corpus callosum agenesis and hydrocephalus. Debate remains concerning the proper management of these lesions. Placement of shunts and microsurgical marsupialization of the cyst are the traditional options. Using endoscopic methods to create areas of communication between the cyst, the ventricular system, and/or the subarachnoid space is an attractive alternative to the use of shunts and microsurgery.

Methods

Between 2000 and 2005, seven consecutive pediatric patients with interhemispheric arachnoid cysts underwent neuroendoscopic treatment involving cystoventriculostomy in two patients, cystocisternostomy in two, and cystoventriculocisternostomy in three. There were three cases of associated hydrocephalus, six cases of corpus callosum agenesis, and one case of corpus callosum hypogenesis.

The follow-up period ranged from 12 to 49 months (mean 31.6 months). Endoscopic procedures were completely successful in all but two patients. In one of the remaining two patients, a repeated endoscopic cystocisternostomy was performed with success because of closure of the previous stoma. In the other, a subcutaneous collection of cerebrospinal fluid (CSF) was managed by insertion of a lumboperitoneal shunt. A subdural collection of CSF developed in three patients; it was treated with insertion of a subduroperitoneal shunt in one patient and managed conservatively in the other two patients, resolving spontaneously without further treatment. Neurodevelopmental evaluation performed in six patients showed normal intelligence (total intelligence quotient [IQ] > 80) in three patients, mild developmental delay (total IQ 50–80) in two, and severe developmental delay (total IQ < 50) in one.

Conclusions

Endoscopic treatment of interhemispheric cysts can be considered a useful alternative to traditional treatments, even if some complications are to be expected, such as subdural or subcutaneous CSF collections and CSF leaks due to thinness of cerebral mantle and to the often-associated multifactorial hydrocephalus.
Interpositional dural graft technique for the treatment of dural arteriovenous fistulas
Authors: Finn Michael , Klimo Paul , Couldwell William T.
Published: January 2008

✓Dural arteriovenous fistulas (dAVFs) are acquired direct arteriovenous shunts that often drain into the dural venous sinus. Treatment options generally involve disrupting the abnormal vascular conduits by using a combination of modalities, including surgical disconnection, radiosurgery, and transarterial and transvenous embolization. Often these modalities provide only partial treatment of fistulous lesions, and thus the fistula recurs and symptoms result. The authors report on a novel surgical technique in which the involved venous sinuses are skeletonized and an interpositional dural substitute is placed between the disconnected sinus and native dura mater and over the pial surface adjacent to the sinus. The technique, which is demonstrated in an illustrative case, is intended to preserve native venous drainage and to prevent recruitment of new vascularization to the venous sinus postoperatively. The authors have not observed reconstitution of fistulas over areas treated with this technique, which offers the advantage of inhibiting vascular ingrowth (refistulization) while maintaining venous sinus patency.
Management of newly diagnosed single brain metastasis using resection and permanent iodine-125 seeds without initial whole-brain radiotherapy: a two-institution experience
Authors: Dagnew Elias , Kanski Jeffrey , McDermott Michael W. , Sneed Penny K. , McPherson Christopher , Breneman John C. , Warnick Ronald E.
Published: January 2008

Object

Whole-brain radiotherapy (WBRT) after resection of a single brain metastasis can cause long-term radiation toxicity. The authors evaluated the efficacy of resection and placement of 125I seeds (without concomitant WBRT) for newly diagnosed single brain metastases.

Methods

In a retrospective review from two institutions (1997–2003), 15 women and 11 men (mean age 55 years) with single brain metastasis underwent gross-total resection and placement of permanent low-activity 125I seeds. Primary systemic cancer sites varied. Patients were monitored clinically and radiographically. With neuroimaging evidence of local recurrence or new distant metastasis, further treatment was administered at the physician's discretion. By the median follow-up evaluation (12 months), the local tumor control rate was 96%. Distant metastases occurred in three patients within 3 months, suggesting synchronous metastasis, and in six patients more than 3 months after treatment, indicating metachronous metastasis. Treatment in these cases included radio-surgery in seven patients, WBRT in two, and resection together with 125I seed placement in one. Two patients who suffered radiation necrosis required operative intervention (lesion diameter > 3 cm, total activity > 40 mCi). All 26 patients who had been treated using resection and placement of 125I seeds had a stable or an improved Karnofsky Performance Scale score. At the last review, nine of 16 living patients showed no evidence of treatment failure. The median actuarial survival rate was 17.8 months (Kaplan–Meier method).

Conclusions

Permanent 125I brachytherapy applied at the initial operation without WBRT provided excellent local tumor control. Local control and patient survival rates were at least as good as those reported for resection combined with WBRT. Although the authors noted a higher incidence of distant metastases compared with that reported in other studies of initial WBRT, these metastases were generally well controlled with a combination of surgery, stereotactic radiosurgery, and, less often, WBRT. Twenty-four patients (92%) never required WBRT, thus avoiding potential long-term radiation-induced neurotoxicity.
Prognosis in patients presenting with brain metastasis from an undiagnosed primary tumor
Authors: D'Ambrosio Anthony L. , Agazzi Siviero
Published: January 2008

Object

The aim of this study was to test the validity of the hypothesis that patients in whom brain metastasis is the first indication of an undiagnosed primary tumor have a better chance of survival than similar patients with a known primary lesion.

Methods

Between January 1983 and December 1998, 342 patients with computed tomography–diagnosed brain metastases were treated at a single institution. Information on potential prognostic factors, including primary diagnosis status, was collected retrospectively. Univariate and multivariate analyses were performed to identify prognostic factors related to survival.

Survival was not statistically different between patients with an undiagnosed primary (UDP) lesion and those with a diagnosed primary (DP) tumor (6 and 4.5 months, respectively; p = 0.097). In the UDP group (122 patients [36%]), survival was not affected by the eventual identification of the primary disease (p = 0.905). The median survival for the entire population was 5.2 months, with 1-, 2-, and 3-year survival rates of 25, 11, and 4%, respectively. Prognostic factors for the overall population included treatment (p < 0.0001), an age less than 65 years (p = 0.004), discharge status (p < 0.001), absence of systemic metastasis (p = 0.036), and asymptomatic cerebral metastasis (p = 0.05).

Conclusions

Treatment modality was the most significant independent variable affecting survival in patients with brain metastases. Eventual identification of a primary tumor does not affect overall survival; therefore, delaying therapeutic intervention in pursuit of a primary diagnosis may not be appropriate. Data in this study failed to demonstrate a statistically significant difference in survival between patients with UDP and those with DP lesions, on first presenting with brain metastases.
Endoscope-assisted placement of a multiperforated shunt catheter into the fourth ventricle via a frontal transventricular approach
Authors: Upchurch Kristen , Raifu Murisiku , Bergsneider Marvin
Published: January 2008

Object

Patients with symptomatic isolated fourth ventricle and multicompartmentalized hydrocephalus benefit from operative treatment, but the optimal surgical approach and technique have yet to be established. The authors report on their experience with the treatment of symptomatic adult patients by endoscope-assisted placement of a fourth ventricle shunt catheter via a frontal transventricular approach.

Methods

The authors describe a retrospective series of four patients treated for isolated fourth ventricle. The surgical technique is described in detail: use of a flexible endoscope with dual-port intraventricular access for direct visualization and for mechanical manipulation of a multiperforated panventricular catheter guided by frameless stereotaxy.

The transventricular approach allowed optimal catheter placement within the fourth ventricle. The use of the flexible endoscope permitted the neurosurgeon to use the endoscope as a tool to guide the ventricular catheter tip within the third ventricle and through the cerebral aqueduct. Clinical outcomes demonstrated neurological and radiographically verified improvement in all patients.

Conclusions

The endoscope-assisted dual-port technique provides a solution to the technical difficulties of fourth ventricle shunt placement. The multiple advantages of this technique include a single ventricular catheter shunt system that equalizes ventricular pressures, a frontal location for the ventricular catheter that facilitates valve placement and programming, and ventricular catheter placement within the fourth ventricle that does not allow the catheter to impinge on the fourth ventricle floor and makes the catheter less prone to obstruction.
Factors contributing to the medical costs of cerebrospinal fluid shunt infection treatment in pediatric patients with standard shunt components compared with those in patients with antibiotic-impregnated components
Authors: Sciubba Daniel M. , Lin Li-Mei , Woodworth Graeme F. , McGirt Matthew J. , Carson Benjamin , Jallo George I.
Published: January 2008

Object

Antibiotic-impregnated shunt (AIS) systems may decrease the incidence of cerebrospinal fluid (CSF) shunt infections. However, there is a reluctance to use AIS components because of their increased cost. In the present study the authors evaluated factors contributing to the medical costs associated with the treatment of CSF shunt infections in a hydrocephalic pediatric population, those implanted with AIS systems compared with those implanted with standard shunt systems.

Methods

The authors retrospectively reviewed data obtained in all pediatric patients who had undergone CSF shunt insertion at their institution over a 3-year period. All patients were followed up for 12 months after surgery. The independent association between AIS catheter use and subsequent shunt infection was assessed by performing a multivariate proportional hazards regression analysis. Factors contributing to the medical costs associated with shunt infection were evaluated.

Results

Two hundred eleven pediatric patients underwent 353 shunting procedures. Two hundred eight shunts (59%) were placed with nonimpregnated catheters and 145 shunts (41%) were placed with AIS catheters. Twenty-five patients (12%) with non-AIS catheters experienced shunt infection, whereas only two patients (1.4%) with AIS catheters had a shunt infection within the 6-month follow-up period (p < 0.01). Among infected patients, infected patients with standard shunt components had a longer average hospital stay, more inpatient complications related to infection treatment, and more multiple organism infections and multiple antibiotic regimens, compared with those with AIS components.

Conclusions

Although individual AIS components are more expensive than standard ones, factors contributing to medical costs are fewer in pediatric patients with infected shunts when the components are antibiotic-impregnated rather than standard.
Pulse pressure waveform in hydrocephalus: what it is and what it isn't
Authors: Czosnyka Marek , Czosnyka Zofia , Keong Nicole , Lavinio Andreas , Smielewski Piotr , Momjian Shahan , Schmidt Eric A. , Petrella Gianpaolo , Owler Brian , Pickard John D.
Published: January 2008

Object

Apart from its mean value, the pulse waveform of intracranial pressure (ICP) is an essential element of pressure recording. The authors reviewed their experience with the measurement and interpretation of ICP pulse amplitude by referring to a database of recordings in hydrocephalic patients.

Methods

The database contained computerized pressure recordings from 2100 infusion studies (either lumbar or intraventricular) or overnight ICP monitoring sessions in patients suffering from hydrocephalus of various types (both communicating and noncommunicating), origins, and stages of management (shunt or no shunt). Amplitude was calculated from ICP waveforms by using a spectral analysis methodology.

Results

The appearance of a pulse waveform amplitude is positive evidence of a technically correct recording of ICP and helps to distinguish between postural and vasogenic variations in ICP. Pulse amplitude is significantly correlated with the amplitude of cerebral blood flow velocity (R = 0.4, p = 0.012) as assessed using Doppler ultrasonography. Amplitude is positively correlated with a mean ICP (R = 0.21 in idiopathic normal-pressure hydrocephalus [NPH]; number of cases 131; p < 0.01) and resistance to cerebrospinal fluid outflow (R = 0.22) but does not seem to be correlated with cerebrospinal elasticity, dilation of ventricles, or severity of hydrocephalus (NPH score). Amplitude increases slightly with age (R = 0.39, p < 0.01; number of cases 46). A positive association between pulse amplitude and increased ICP during an infusion study is helpful in distinguishing between hydrocephalus and predominant brain atrophy. A large amplitude is associated with a good outcome after shunting (positive predictive power 0.9), whereas a low amplitude has no predictive power in outcome prognostication (0.5). Pulse amplitude is reduced by a properly functioning shunt.

Conclusions

Proper recording, detection, and interpretation of ICP pulse waveforms provide clinically useful information about patients suffering from hydrocephalus.
Longstanding overt ventriculomegaly in adults: pitfalls in treatment with endoscopic third ventriculostomy
Authors: Rekate Harold L.
Published: January 2008

Object

The recently described condition of longstanding overt ventriculomegaly in adults (LOVA) has not been defined in terms of the need for intervention, timing of intervention, and ideal treatment. The purpose of this review was to evaluate the role of endoscopic third ventriculostomy (ETV) in the treatment of LOVA.

Methods

Data collected in six patients with LOVA who had undergone ETV were reviewed retrospectively in terms of the definition of treatment success, rates of success, complications, and outcome. All six patients presented with headache disorders. In all patients, triventricular hydrocephalus had been diagnosed as aqueductal stenosis, and head circumference measurements were above the 98th percentile. All six had undergone successful ETV as documented by the free flow of cerebrospinal fluid into the basal cisterns, which remained open throughout the follow-up period. After the procedure, one patient experienced a mild degree of difficulty with short-term memory. Five patients remained symptomatic or had symptoms requiring further treatment 3 months to 3 years after ETV. Four patients received ventriculoperitoneal shunts, and one underwent venous stenting for high intracranial pressure after successful ETV. In two patients in whom aqueductal stenosis had been diagnosed, the sylvian aqueduct was patent after the procedure.

Conclusions

In LOVA patients who present with headaches, ETV may not lead to improvement in the headaches. Despite the presence of triventricular hydrocephalus, closure of the aqueduct may be a secondary phenomenon, and flow through the aqueduct may be reestablished after ETV. If intracranial hypertension persists after successful ETV, its cause may be increased venous sinus pressure.
Observations regarding failure of cerebrospinal fluid shunts early after implantation
Authors: Ferguson Sherise D. , Michael Nancy , Frim David M.
Published: January 2008

✓Despite advances in cerebrospinal fluid (CSF) diversionary techniques, shunt failure due to infection or malfunction remains a persistent problem in hydrocephalus care. The aim of this study was to evaluate the independent predictors of early shunt survival after implantation in a large cohort of patients. The authors retrospectively reviewed the records of all patients who had undergone shunt implantation procedures at their institution during an 8-year period. They analyzed the independent predictors of shunt survival in 116 failed shunt placement procedures (infection or malfunction) by performing univariate and multivariate factorial analyses. Analysis of the 116 failed shunts in the 396 new shunt placement procedures performed revealed that age was a significant independent predictor of shunt survival time in failures due to malfunction (p < 0.05) as well as infection (p < 0.05). In addition, a significant relationship between patient race and shunt survival was also found. As suggested by data in other studies focused on this outcome, early shunt failure occurs sooner in younger patients. Interestingly, this study is one of few whose data have revealed that race may affect shunt failure after implantation. Specifically, shunt failure due to infection resulted in significantly shorter shunt survival time in non-white patients compared with that in white patients. Among the shunts that failed due to malfunction, however, white patients had shorter shunt survival times.
Intracranial Pressure: More Than a Number
Authors: Czosnyka Marek , Smielewski Peter , Timofeev Ivan , Lavinio Andrea , Guazzo Eric , Hutchinson Peter , Pickard John D.
Published: January 2008

✓Many doctors involved in the critical care of head-injured patients understand intracranial pressure (ICP) as a number, characterizing the state of the brain pressure–volume relationships. However, the dynamics of ICP, its waveform, and secondarily derived indices portray useful information about brain homeostasis. There is circumstantial evidence that this information can be used to modify and optimize patients' treatment. Secondary variables, such as pulse amplitude and the magnitude of slow waves, index of compensatory reserve, and pressure–reactivity index (PRx), look promising in clinical practice. The optimal cerebral perfusion pressure (CPP) derived using the PRx is a new concept that may help to avoid excessive use of vasopressors in CPP-oriented therapy. However, the use of secondary ICP indices remains to be confirmed in clinical trials.
Surgery for brain edema
Authors: Hutchinson Peter , Timofeev Ivan , Kirkpatrick Peter
Published: January 2008

✓Brain edema is a common pathophysiological process seen in many neurosurgical conditions. It can be localized in relation to focal lesions or generalized in diffuse types of brain injury. In addition to local adverse effects occurring at a cellular level, brain edema is associated with raised intracranial pressure (ICP), and both phenomena contribute to poor outcome in patients. One of the goals in treating patients with acute neurosurgical conditions in intensive care is to control brain edema and maintain ICP below target levels. The mainstay of treatment is medical therapy to reduce edema, but in certain patients—for example, those with diffuse severe traumatic brain injury (TBI) and malignant middle cerebral artery infarction—such treatment is not effective. In these patients, opening the skull (decompressive craniecto-my) to reduce ICP is a potential option. In this review the authors discuss the role of decompressive craniectomy as a surgical option in patients with brain edema in the context of a variety of pathological entities. They also address the current evidence for the technique (predominantly observational series) and the ongoing randomized studies of decompressive craniectomy in TBI and ischemic stroke.
Vasogenic edema due to tight junction disruption by matrix metalloproteinases in cerebral ischemia
Authors: Rosenberg Gary A. , Yang Yi
Published: January 2008

✓Cerebral ischemia causes cell swelling and breakdown of the blood–brain barrier (BBB). Cytotoxic edema results from energy failure, and vasogenic edema occurs when the blood vessels are damaged. Proteases and free radicals are the end result of a molecular injury cascade. Matrix metalloproteinases (MMPs) are a gene family of extracellular matrix-degrading enzymes that disrupt the BBB. Tight junction proteins (TJPs), occludin and claudin-5, which form the endothelial barrier, are vulnerable to attack by MMPs. Basal lamina proteins, such as fibronectin, laminin, and heparan sulfate, are also degraded by MMPs. Reperfusion injury leads to a biphasic opening of the BBB, with the early opening occurring several hours after the onset of reperfusion due to activation of the constitutive enzyme gelatinase A (MMP-2). This initial opening is transient and followed 24 to 48 hours later by more intense damage to the blood vessel, which is associated with the expression and activation of gelatinase B (MMP-9) and stromelysin-1 (MMP-3). Synthetic MMP inhibitors restore the early integrity of the BBB but are ineffective in the later opening. Because these inhibitors block MMPs involved in angiogenesis and neurogenesis, they also slow recovery. The challenge is to identify agents that will protect the BBB, blocking vasogenic edema without interfering with recovery.
Tissue hyperosmolality and brain edema in cerebral contusion
Authors: Kawamata Tatsuro , Mori Tatsuro , Sato Shoshi , Katayama Yoichi
Published: January 2008

Severe cerebral contusion is often associated with nonhemorrhagic mass effect that progresses rapidly within 12 to 48 hours posttrauma. The mechanisms underlying such a rapid progression of mass effect cannot be fully explained by classic concepts of vasogenic and cytotoxic brain edema. Data from previous clinical trials, including diffusion-weighted magnetic resonance imaging studies, have indicated that cells in the central (core) area of the contusion undergo shrinkage, disintegration, and homogenization, whereas cellular swelling is located predominately in the peripheral (rim) area during this period. The authors hypothesized that high osmolality within the contused brain tissue generates an osmotic potential across the central and peripheral areas or causes blood to accumulate a large amount of water. To elucidate the role of tissue osmolality in contusion edema, they investigated changes in tissue osmolality, specific gravity, and ion concentration in contused brain in both experimental and clinical settings. Their results demonstrated that cerebral contusion induced a rapid increase in tissue osmolality from a baseline level of 311.4 ± 11.3 to 402.8 ± 15.1 mOsm at 12 hours posttrauma (p < 0.0001). Specific gravity in tissue significantly decreased from 1.0425 ± 0.0026 to 1.0308 ± 0.0028 (p < 0.01), reflecting water accumulation in contused tissue. The total ionic concentration [Na+] + [K+] + [Cl−] did not change significantly at any time point. Inorganic ions do not primarily contribute to this elevation in osmolality, suggesting that the increase in colloid osmotic pressure through the metabolic production of osmoles or the release of idiogenic osmoles can be a main cause of contusion edema.
Mechanisms of tumor-related brain edema
Authors: Stummer Walter
Published: January 2008

✓Cerebral edema contributes strongly to symptoms associated with brain tumors. Although the introduction of corticosteroids has greatly simplified treatment of patients with newly diagnosed tumors, these drugs are associated with marked side effects during the long-term treatment that is often necessary in the recurrences. Therefore, a better understanding of mechanisms related to the evolution and clearance of tumor-related edema with the aid of modern imaging and molecular methodology is clearly necessary. Recently, researchers have focused on molecular mechanisms of edema development and have demonstrated alternative routes—such as the inhibition of vascular endothelial growth factor receptor inhibitors—to be explored for treating edema. In this review the author focuses on established and current concepts regarding the pathophysiology of cerebral edema and its treatment.
Management of metastatic tumors invading the peripheral nervous system
Authors: Gachiani John , Kim Daniel H. , Nelson Adriane , Kline David
Published: January 2008

Object

The authors present the results of a retrospective review of 37 surgically treated metastases to nerve (malignant peripheral non–neural sheath nerve tumors). Tumor frequencies, presentations, management, and prognosis are discussed.

Methods

Thirty-seven patients who were treated for metastases to nerve between 1969 and 2006 at the Louisiana State University Health Sciences Center were identified in a review of patient records. Notes regarding patient history and physical examination findings were reviewed to provide information on presenting symptoms and signs. Imaging and histopathological examination results were also reviewed. Cases were analyzed depending on the primary tumor and the location of metastasis.

Results

There included 37 surgically treated lesions, 16 of which originated in the breast and 10 of which originated in the lung. In two cases melanomas had metastasized to nerve, and one tumor each had metastasized from the bladder, rectum, skin, head and neck, and thyroid, and from a primary Ewing sarcoma. There was a single lymphoma that had metastasized to the radial nerve and one chordoma and one osteosarcoma, each of which had metastasized to the brachial plexus.

Conclusions

The nervous system is involved in numerous ways by oncological process. Direct involvement of the peripheral nervous system occurs mostly from direct extension, although it occasionally occurs because of distant spread from the primary tumor to nerve. Surgical excision of the metastatic lesion with margins has been useful mostly in the control of pain. Nevertheless, patients eventually succumb to their primary malignancy.
Lipomatous, vascular, and chondromatous benign tumors of the peripheral nerves
Authors: Châtillon Claude-Edouard , Guiot Marie-Christine , Jacques Line
Published: January 2008

Benign peripheral nerve lesions of lipomatous, vascular, and chondromatous origin are very rare. Only one previous case of brachial plexus involvement by such a tumor has been reported. The authors report on their experience with peripheral nerve tumors in three patients and review the available literature on these topics. The three cases discussed include a 44-year-old woman with an intraneural lipoma of the right middle trunk, a 40-year-old woman with an intraneural hemangioma infiltrating the right posterior cord, and a newborn male with a predominantly cartilaginous hamartoma originating from the right C-5 nerve root.

The literature review yielded six previous cases of intraneural lipoma, approximately 50 cases of lipofibromatous hamartoma, 13 cases of intraneural hemangioma, and no previous case of cartilaginous hamartoma originating from a nerve. Intraneural lipomas are well encapsulated, and gross-total resection can be achieved. Lipofibromatous hamartomas are diffusely infiltrative; decompressive debulking and neurolysis is often the most appropriate initial approach for patients with symptomatic lesions. Resection of intraneural hemangiomas can be achieved but may require nerve resection and repair in some cases. Debulking has been reported to provide prolonged symptomatic relief in these lesions, and preoperative embolization and postoperative radiotherapy were beneficial in the case presented here. To the authors' knowledge, this is the first reported case of a cartilaginous hamartoma infiltrating a peripheral nerve. Gross-total resection of symptomatic intraneural lipomas is feasible and apparently curative. The optimal treatment for lipofibromatous hamartomas and vascular and chondromatous lesions of the peripheral nerves is uncertain and should be guided by the severity of symptoms.
Nerve sheath tumor surgery: case-guided discussion of ambiguous findings, appropriateness of removal, repeated surgery, and nerve repairs
Authors: Kretschmer Thomas , Antoniadis Gregor , Heinen Christian , Börm Wolfgang , Scheller Christian , Richter Hans-Peter , Koenig Ralph W.
Published: January 2008

✓In this article the authors attempt to raise awareness of the pitfalls and controversial issues in nerve tumor surgery. In a case-guided format, examples of ambiguous findings, inappropriate tumor removal, repeated surgery, and nerve repairs are provided. The authors also discuss the need to establish a correct diagnosis preoperatively and to avoid the erroneous identification of malignant peripheral nerve sheath tumors (MPNSTs). They emphasize that not all of the principles of soft tissue sarcoma treatment protocols are applicable to MPNST. A situation of repeated surgery for supposedly malignant tumor is described, and an outline of the indications for, and an approach to, repair after lesion removal is given.
Extraabdominal desmoid tumors
Authors: Dafford Kurtus , Kim Daniel , Nelson Adriane , Kline David
Published: January 2008

Object

Desmoid tumors are fibrous, slow-growing, nonmalignant tumors with a low potential for metastasis. These lesions show a high propensity for infiltrative growth with local invasion.

Methods

The authors undertook a retrospective study of 15 desmoid tumors in 11 women and four men (ranging in age from 32 to 67 years; median 48 years) treated at their institution. This study included further resection for recurrent tumors in nine of 15 patients (60%).

Results

There were 13 patients (86%) with brachial plexus lesions, one patient (7%) with a lumbar plexus lesion, and one (7%) with a peroneal nerve lesion. There was a female predominance in the study group of 2.75:1. Four patients (27%) reported improvement in pain status, six (40%) reported no change from their preoperative pain levels, and five (33%) reported worsened pain symptoms. There was tumor recurrence in two patients (13%) leading to further surgical intervention.

Conclusions

This case series included many recurrent desmoid tumors of the brachial plexus. Most of these lesions were relatively large tumors, predominantly involved with the plexal elements adding to the challenge of the resection. Currently, function-sparing excision is considered the optimal treatment for desmoid tumors arising in extraabdominal sites. Adjunctive radiation or brachytherapy is reserved for a patient with further recurrence in whom resection would be disfiguring or in whom the disease is more refractory.
Desmoid-type fibromatosis involving the brachial plexus
Authors: Seinfeld Joshua , Kleinschmidt-Demasters Bette K. , Tayal Shalini , Lillehei Kevin O.
Published: January 2008

✓Desmoid-type fibromatosis involving the brachial plexus is a rare and challenging disease. Due to involvement of crucial neurovascular structures, wide local excision of the associated fibromas is rarely feasible and recurrence is common. The authors describe their experience in four surgically treated patients with desmoid-type fibromatosis involving the brachial plexus and review the relevant neurosurgical literature.

All tumors were assessed for c-KIT oncogene mutations in hopes of establishing a biological basis for using the tyrosine kinase inhibitor imatimib mesylate as an adjuvant therapy. Three patients experienced tumor recurrence requiring reoperation. Fractionated radiotherapy achieved local control in three patients, and the disease in one patient progressed beyond the treatment field. Single base pair changes at exon 10 of the c-KIT oncogene were identified in three tumors. One tumor with this mutation did not respond to treatment with imatimib mesylate. A review of the literature revealed 17 additional patients in two different case series. Analysis of these cases emphasizes the need for careful resection in patients with desmoid-type fibromatosis and supports the conclusion that without adjuvant radiotherapy a high local recurrence rate can be anticipated. For optimal local disease control, the authors recommend post-surgical radiation therapy regardless of the extent of resection achieved. The mutational status of the c-KIT oncogene remains an intriguing biological marker that in the future may predict which lesions will be responsive to imatimib mesylate; larger series will be necessary to test this hypothesis.
Granular cell tumor involving the axillary nerve: an unusual occurrence
Authors: Mindea Stefan A. , Kaplan Keith J. , Howard Michael A. , O'leary Shaun T.
Published: January 2008

✓Granular cell tumors (GCTs) are benign lesions that, paradoxically, despite originating from the Schwann cell, are most commonly seen in nonneuronal tissue including the skin, subcutaneous tissue, and tongue. Their presence in the brachial plexus is quite rare, but their involvement of peripheral nerves is exceptional. The authors report on a case of GCT involving the axillary nerve in a 54-year-old woman who underwent complete resection of the lesion. To the author's knowledge, this case marks the first report of a GCT involving the axillary nerve. Aspects pertaining to the radiographic and histopathological features as well as the surgical management of this lesion are discussed.
Experimental therapeutic approaches to peripheral nerve tumors
Authors: Riley Jonathan , Spiotta Alejandro , Boulis Nicholas
Published: January 2008

✓Discovery that the Schwann cell is the primary cell type responsible for both the neurofibroma as well as the schwannoma has proven to represent a crucial milestone in understanding the pathogenesis of peripheral nerve tumor development. This information and related findings have served as a nidus for research aimed at more fully characterizing this family of conditions. Recent discoveries in the laboratory have clarified an understanding of the molecular mechanisms underlying the pathogenesis of benign peripheral nerve tumors. Similarly, the mechanisms whereby idiopathic and syndromic (NF1- and NF2-associated) nerve sheath tumors progress to malignancy are being elucidated. This detailed understanding of the molecular pathogenesis of peripheral nerve tumors provides the information necessary to create a new generation of therapies tailored specifically to the prevention, cessation, or reversal of pathological conditions at the fundamental level of dysfunction. The authors review the data that have helped to elucidate the molecular pathogenesis of this category of conditions, explore the current progress toward exploitation of these findings, and discuss potential therapeutic avenues for future research.
Oncolytic herpes simplex virus therapy for peripheral nerve tumors
Authors: Jeyaretna Deva S. , Rabkin Samuel D. , Martuza Robert L.
Published: January 2008

✓Oncolytic viruses are one of many emerging cancer therapies. The surgical management of peripheral nerve tumors carries an inherent risk of damaging the nerves involved and so the search for novel therapies with reduced risk of morbidity continues. In this review the authors discuss the use of oncolytic herpes simplex virus (HSV) in the treatment of peripheral nerve tumors. Herpes simplex virus has a number of characteristics that make it a useful oncolytic vector, including its large, sequenced genome that can accommodate multiple transgenes, its lack of insertional mutagenesis, its ability to infect a wide array of cell types in various species, and the availability of well-established antiviral therapies to treat it. The efficacy of oncolytic HSV therapy against schwannomas and malignant peripheral nerve sheath tumors has been studied in multiple experimental models both in vitro and in vivo. The virus utilizes cell pathways unique to tumors to enhance its oncolytic efficacy, preferentially and effectively targeting and destroying peripheral nerve tumor cells without harming normal cells. This effect is augmented by trans-genes expressing antiangiogenic factors, such as dominant-negative fibroblast growth factor receptor and platelet factor 4, and displays synergy with chemotherapy. Different oncolytic HSV vectors have been tested, including hrR3, G207, and G47Δ. In addition, new animal models have been developed to test the efficacy of oncolytic HSV therapy in peripheral nerve tumors. The safety of oncolytic HSV is well-established and has been tested in nonhuman primates and in human clinical trials.
Clinical examination of brachial and pelvic plexus tumors
Authors: Lwu Shelly , Midha Rajiv
Published: January 2008

✓A thorough history and physical examination are fundamental to the assessment of patients with brachial and pelvic plexus tumors. Typical of most peripheral nerve tumors, the presenting symptoms and signs are few, and if present, can be subtle. Presenting complaints may include a palpable mass lesion, either symptomatic or asymptomatic; sensory alterations; pain; motor deficits; visceral symptoms; or autonomic dysfunction. Motor deficits are usually a late feature in the pathogenesis of this lesion, and a progressive course of pain and significant sensory and motor deficits suggests a malignant pathological process. A detailed family history may reveal familial syndromes and neurocutaneous disorders that predispose the patient to neoplasia, such as neurofibromatosis. The physical examination should be conducted in a systematic fashion, looking for any cutaneous features and motor and sensory deficits. The mass should also be examined for form, consistency, and mobility. An irregular, firm, and immobile mass suggests a malignant lesion. Complete and accurate clinical information must be gathered to pinpoint the anatomical localization of the lesion and formulate a differential diagnosis.
Operative steps in management of benign nerve sheath tumors
Authors: Ball Jonathon R. , Biggs Michael T.
Published: January 2008

✓Benign peripheral nerve sheath tumors include the neurofibroma, schwannoma, and their plexiform variants. Operative management begins with an assessment of the relative risks associated with surgery compared with observation. The risks of observation include the risk of malignancy, the progression of symptoms, risk of delayed surgery, and ongoing patient suffering. The risks of surgery include anesthetic problems, wound complications, and neurological injury. New neurological deficits have been reported to occur in approximately 10 to 15% of surgically treated cases. In general, surgery is recommended for symptomatic or progressive lesions. Although the surgical approach will vary depending on the location, type, and extent of tumor, adherence to certain principles will facilitate success. Adequate visualization and successful removal will be achieved with detailed anatomical knowledge, an adequate extensile exposure to visualize the proximal and distal tumor extent, circumferential dissection of the tumor, microsurgical dissection under appropriate magnification, and meticulous hemostasis throughout the procedure.