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Anthony L. D'Ambrosio and Siviero Agazzi

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.

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Siviero Agazzi, Alain Reverdin and Daniel May

Object. The authors conducted a retrospective study to provide an independent evaluation of posterior lumbar interbody fusion (PLIF) in which impacted carbon cages were used. Interbody cages have been developed to replace tricortical interbody grafts in anterior and PLIF procedures. Superior fusion rates and clinical outcomes have been claimed by the developers.

Methods. In a retrospective study, the authors evaluated 71 consecutive patients in whom surgery was performed between 1995 and 1997. The median follow-up period was 28 months. Clinical outcome was assessed using the Prolo scale. Fusion results were interpreted by an independent radiologist.

The fusion rate was 90%. Overall, 67% of the patients were satisfied with their outcome and would undergo the same operation again. Based on the results of the Prolo scale, however, in only 39% of the patients were excellent or good results achieved. Forty-six percent of the work-eligible patients resumed their working activity. Clinical outcome and return-to-work status were significantly associated with socioeconomic factors such as preoperative employment (p = 0.03), compensation issues (p = 0.001), and length of preoperative sick leave (p = 0.01). Radiographically demonstrated fusion was not statistically related to clinical outcome (p = 0.2).

Conclusions. This is one of the largest independent series in which PLIF with cages has been evaluated. The results show that the procedure is safe and effective with a 90% fusion rate and a 66% overall satisfaction rate, which compare favorably with those of traditional fixation techniques but fail to match the higher results claimed by the innovators of the cage techniques. The authors' experience confirms the reports of others that many patients continue to experience incapacitating back pain despite successful fusion and neurological recovery.

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Ali A. Baaj, Siviero Agazzi and Harry van Loveren

Cerebral revascularization constitutes an important treatment modality in the management of complex aneurysms, carotid occlusion, tumor, and moyamoya disease. Graft selection is a critical step in the planning of revascularization surgery, and depends on an understanding of graft and regional hemodynamics, accessibility, and patency rates. The goal of this review is to highlight some of these properties.

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Siviero Agazzi, Luca Regli, Antoine Uske, Philippe Maeder and Nicolas de Tribolet

✓ Developmental venous anomalies (DVAs) are common congenital variations of normal venous drainage that are known for their benign natural history. Isolated cases of symptomatic DVAs with associated arteriovenous (AV) shunts have recently been reported. The present case, in which thrombosis occurred in a DVA involving an AV shunt, raises intriguing questions regarding the clinical characteristics of these lesions and can be used to argue in favor of considering such lesions to be arteriovenous malformations (AVMs).

A 39-year-old man presented with acute thrombosis in a complex system of anomalous hemispheric venous drainage, which included two distinct DVAs, one of which involved an AV shunt. The hemodynamic turbulences induced by a communication between shunted and normal venous outflows were the possible predisposing factor of the thrombosis. Follow-up angiographic and magnetic resonance images revealed complete recanalization of the thrombosed vessel and provided a thorough visualization of the particular angioarchitecture of the DVA.

Acute thrombosis within a DVA with an AV shunt has not been reported previously and, thus, this case can be added to other reports of complications that arise in this particular type of DVA. The authors hypothesize that the presence of an AV shunt in a DVA is a risk factor for aggressive clinical behavior of the anomaly, rendering those lesions prone to complications similar to AVMs.

Although no treatment can be offered, the presence of an AV shunt in a DVA warrants close follow-up observation because such lesions may represent a particular subtype of AVM and, therefore, may exhibit an aggressive clinical behavior.

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Siviero Agazzi, Harry R. van Loveren, Creighton J. Trahan and Wesley M. Johnson

Object

The authors provide a surgical description of the ventral approach to the cervical spine in a goat model and identify selection of the most appropriate level for testing interbody devices. These constructs are designed for implantation in humans during anterior cervical discectomy and fusion. Such description and guidelines for level selection have never been published in either the medical or veterinarian literature.

Methods

The study comprised three phases: surgical, anatomical, and morphometric. Six goats underwent ventral approaches and were later killed; their necks were dissected and the cervical spines were processed to obtain clean specimens of the vertebral bodies. Measurements were made at each level using a contact digitizer.

Results

The anterolateral bone spurs, called alar processes, and the increased thickness of the longus colli muscle are the surgically relevant characteristics in the goat. The morphometric analysis showed that C2–3 is the most suitable level for implantation of interbody devices. The vertebral endplates at the C2–3 level are relatively flat and parallel to each other, and are perpendicular to the spinal canal axis. More distally, the endplates adopt a more curved arrangement, and the endplate angle becomes significantly greater than 90°. The authors describe anatomical landmarks that are important to safely and effectively perform a ventral cervical spinal approach in the goat.

Conclusions

The authors' model identifies C2–3 as the most appropriate level for animal testing of cervical implants because of its similarity to human anatomy. Further study with rigorous biomechanical range of motion evaluation of each caprine cervical level is needed.

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Justin M. Sweeney, Rohit Vasan, Harry R. van Loveren, A. Samy Youssef and Siviero Agazzi

The object of this study was to describe a unique method of managing ventriculostomy catheters in patients on antithrombotic therapy following endovascular treatment of ruptured intracranial aneurysms. The authors retrospectively reviewed 3 cases in which a unique method of ventriculostomy management was used to successfully avoid catheter-related hemorrhage while the patient was on dual antiplatelet therapy. In this setting, ventriculostomy catheters are left in place and fixed to the calvarium with titanium straps effectively ligating them. The catheter is divided and the distal end is removed. The proximal end can be directly connected to a distal shunt system during this stage or at a later date if necessary. The method described in this report provided a variety of management options for patients requiring external ventricular drainage for subarachnoid hemorrhage. No patient suffered catheter-related hemorrhage.

This preliminary report demonstrates a safe and effective method for discontinuing external ventricular drainage and/or placing a ventriculoperitoneal shunt in the setting of active coagulopathy or antithrombotic therapy. The technique avoids both the risk of hemorrhage related to catheter removal and reinsertion and the thromboembolic risks associated with the reversal of antithrombotic therapy. Some aneurysm centers have avoided the use of stent-assisted coiling in cases of ruptured aneurysms to circumvent ventriculostomy-related complications; however, the method described herein should allow continued use of this important treatment option in ruptured aneurysm cases. Further investigation in a larger cohort with long-term follow-up is necessary to define the associated risks of infection using this method.

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Ali A. Baaj, Siviero Agazzi, Zafar A. Sayed, Maria Toledo, Robert F. Spetzler and Harry van Loveren

Moyamoya disease (MMD) is a progressive, occlusive disease of the distal internal carotid arteries associated with secondary stenosis of the circle of Willis. Symptoms include ischemic infarcts in children and hemorrhages in adults. Bypass of the stenotic vessel(s) is the primary surgical treatment modality for MMD. Superficial temporal artery-to-middle cerebral artery bypass is the most common direct bypass method. Indirect techniques rely on the approximation of vascularized tissue to the cerebral cortex to promote neoangiogenesis. This tissue may be in the form of muscle, pericranium, dura, or even omentum. This review highlights the surgical options available for the treatment of MMD.

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Siviero Agazzi, Stanley Chang, Mitchell D. Drucker, A. Samy Youssef and Harry R. Van Loveren

The authors describe the case of a 76-year-old man in whom reversible sudden blindness developed after a percutaneous balloon compression rhizotomy for trigeminal neuralgia. His eye became tense and swollen with intraocular pressures of 66 mm Hg. Acetazolamide was administered, and visual acuity (20/50) returned within several months. Despite correct needle placement, the intraocular pressure rose acutely because of transient occlusion of the orbital venous drainage through the cavernous sinus; this was reversed with aggressive medical treatment.

In cadaveric studies (dried skull and formalin-fixed head), the authors studied the mechanism of optic nerve penetration. Their findings showed that excessive cranial angulation of the needle with penetration of the inferior orbital fissure can directly traumatize the optic nerve in the orbital apex. Direct trauma to the optic nerve can therefore be prevented by early and repeated confirmation of the needle trajectory with lateral fluoroscopy before penetration of the foramen ovale.

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Jamie J. Van Gompel, Jaymin Patel, Chris Danner, A. Nanhua Zhang, A. A. Samy Youssef, Harry R. van Loveren and Siviero Agazzi

Object

Tinnitus is a known presenting symptom of acoustic neuromas, but little is known about the impact of observation or treatment on tinnitus. Most patients experience improvement with treatment, while others may worsen. Therefore, this study was designed to assess the overall impact of observation and treatment on tinnitus outcome in patients with acoustic tumors.

Methods

Data from the 2007–2008 Acoustic Neuroma Association survey were used. Tinnitus severity was graded both at presentation and at last follow-up for all patients questioned. This data set was analyzed using the Student t-test and a linear regression model adjusted for possible confounders.

Results

Overall there were more patients receiving intervention (n = 1138) for their acoustic neuromas than observation (n = 289). Presenting tumor size positively correlated with tinnitus severity score. Regardless of treatment (microsurgery or stereotactic radiosurgery), tinnitus improved at last follow-up and worsened in those who were observed (p = 0.02). When comparing microsurgical options, retrosigmoid and translabyrinthine resection improved tinnitus symptoms (both p < 0.01). Stereotactic radiosurgery had a treatment effect similar to microsurgery.

Conclusions

Presenting tinnitus severity correlates strongly with tumor size. Furthermore, regardless of treatment, there appears to be an overall reduction in tinnitus severity for all forms of microsurgery and stereotactic radiosurgery. Importantly, observation leads to a worsening in symptomatic tinnitus and therefore should be weighed in the treatment recommendation.

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Tsz Lau, Raul Olivera, Timothy Miller Jr., Katheryne Downes, Christopher Danner, Harry R. van Loveren and Siviero Agazzi

Object

Recent natural history studies of vestibular schwannomas (VSs) suggest that most of these tumors do not grow. The impact of these new data on management trends in the US is currently unknown. The aim in the present study was to evaluate current trends in the treatment of VS in the US by analyzing a national cancer database.

Methods

The Surveillance, Epidemiology, and End Results Program is a national database maintained by the National Cancer Institute representing 26% of the US population. Data from the database were downloaded using provided software. Cases were isolated based on histology codes and the site code. Data from 2004 to 2007 were included in the analysis. The number of patients undergoing resection was compared with the number treated with beam radiation and observation, based on tumor size.

Results

Three thousand six hundred fifty cases were identified in the database. Over the study period, management choices for VSs showed a significant change only for tumors with a diameter < 2 cm. In this tumor category, a decrease in resection and an increase in radiation were observed, with observation showing a modest increase but remaining low at an average of 25%.

Conclusions

Study data demonstrated a shift in the management of small VSs in the US between 2004 and 2007, with microsurgical removal giving way to radiation treatment and the overall rate for observation remaining low and stable. With recent literature suggesting that the majority of small tumors do not grow, the authors assert that VSs are being overtreated in the US.