Franco Benech

Brain metastases from unknown primary tumour : A prospective study

Abstract The best management of patients with brain metastases from an unknown primary tumour is still unclear, as data are scarce and studies are retrospective. We report 33 patients with biopsy-proven brain metastases from a primary tumour not found at the first investigations, who were treated by surgery and/or radiotherapy and followed with serial CT until death. Median survival time for all patients was 10 months and survival rates at 6 months, 1 year and 2 years were 76 %, 42 % and 15 % respectively. Patients with single brain metastasis treated by gross total resection and whole-brain radiotherapy (WBRT) had a median survival of 13 months with 76 % alive at 6 months, 57 % at 1 year and 19 % at 2 years. Patients with multiple brain metastases who underwent either WBRT alone or WBRT preceded by gross total resection of the symptomatic lesions had a poorer prognosis: median survival of 6–8 months with 50–100 % alive at 6 months, 17–20 % at 1 year and none alive at 2 years. In 85 % of patients with a single brain metastasis a significant improvement in neurological functions was observed after surgical resection; among patients with multiple brain metastases a neurological improvement was observed in all patients who had a resection of symptomatic lesions and only in a half of patients who had WBRT alone. During the follow-up the primary tumour was found in 27/33 patients (82 %) and was located in the lung in 78 %. Between 1987 and 1991 (with limited screening for the primary tumour in the follow-up) the unknown tumours were 6/15 (40 %); in the more recent period (1992–1996) (CT-based screening for the primary tumour in the follow-up) no primary tumour remained unknown but overall survival has not significantly improved. The number of brain metastases was the only significant factor affecting survival after both univariate and multivariate analysis. This study suggests that, in patients with both single and multiple brain metastases from an undetected primary site when first studied, surgery and/or WBRT enable the control of the brain disease, partly because the systemic disease may be silent for a prolonged time. Only a few asymptomatic patients may benefit from an early detection and treatment of the primary tumour during the follow-up.

Cystic versus solid vestibular schwannomas: a series of 80 grade III–IV patients

Cystic acoustic neuromas are less frequent than solid ones and present different clinical and radiological features. Cystic schwannomas are larger, show a shorter clinical history and a different risk of postoperative complications. This study was designed to compare surgical results and complications of solid and cystic vestibular schwannomas of matching size operated upon via either a retrosygmoid or a translabyrinthine approach. The study included 80 patients presenting with grade III and IV acoustic vestibular schwannomas referred to the Neurosurgical and ENT team in the Department of Neuroscience of Torino, Italy. Twenty-six were cystic and 54 were solid tumours. Clinical history, surgical results and complications were compared between the two groups. In cystic tumors, rapid clinical worsening is common, due to sudden expansion of cystic elements. Tighter adherences are found between cystic tumours and nervous elements (particularly brainstem and possibly facial nerve), once compared to solid ones. Operative morbidity appears to be higher in cystic tumours. A wait and see policy should not to be applied to patients with cystic tumours. Careful technique, possibly sharp dissection, to divide the tumour adherences from the nervous tissue must be employed, in order to avoid lesions on brainstem veins and traction on a thin facial nerve. Severe complications may be caused by the excessive efforts to dissect brainstem adherences.

Vasospasm after SAH due to aneurysm rupture of the anterior circle of Willis: value of TCD monitoring

Abstract Objective: The aim of this study was to verify the presence of angiographic vasospasm in patients with transcranial Doppler (TCD) of high velocities after subarachnoid hemorrhage (SAH). Methods: Seven hundred and eighty-six cases admitted within 48 hours after SAH due to the rupture of anterior circulation aneurysm, were prospectively studied with TCD. In cases of TCD velocities higher than 120 cm/s (TCD vasospasm), the patient underwent a control angiography. Hunt–Hess and Fishers grade on admission CT and location of the aneurysm were related to occurrence of TCD vasospasm. The increase in TCD velocities within 24 hours was calculated and related to the presence of cerebral ischemia on discharge CT, considering three groups of patients: Group A with an increase in velocities higher than 60%, Group B with an increase in velocities between 30 and 60%, and Group C with an increase in velocities lower than 30%. Results: TCD vasospasm was observed in 216 patients (27%). In 97% of patients with TCD vasospasm on middle cerebral artery (MCA) and in 71% with TCD vasospasm on anterior cerebral artery (ACA), control angiography confirmed the vasospasm, with a significant lower diagnostic TCD predictivity of ACA spasm (χ2=28.204, p=0.000). The overall positive predictive value of TCD was 89%. There was no significant correlation of TCD vasospasm with clinical status on admission and location of the aneurysm, but a significant correlation between occurrence of TCD vasospasm and Fishers grade (χ2=15.470, p=0.002) and between the increase rate in TCD velocities and cerebral ischemia (χ2=56.564, p=0.000). Conclusion: Our study shows a good correlation between TCD and angiography to detect vasospasm on MCA, but the correlation is low for ACA. TCD alone cannot discriminate different hemodynamic pathways after SAH.

Retrosigmoid approach for vestibular neurectomy in Meniere’s disease

SummaryBackground. Vestibular nerve section is considered to be the most effective surgical procedure to control intractable symptoms secondary to Menière’s disease (MD). This study was developed to analyze the adequacy of retrosigmoid vestibular neurectomy in terms of vertigo control, hearing preservation and clinical complications of this procedure.Methods. A retrospective review was carried out on 14 patients affected by definite unilateral MD who underwent vestibular neurectomy via the retrosigmoid approach.Findings. One patient was lost from follow-up; another one had only a short postoperative observation. At follow-up performed on 12 cases, no patients reported any crisis of acute vertigo. Four patients were free from any vestibular symptoms, while 8 reported some slight gait disturbances. Hearing function was preserved in 10 patients and improved in 2. 1 year postoperative vestibular function was absent at the side operated on and unchanged on the other side in all the cases.Conclusions. Vestibular neurectomy via the retrosigmoid approach can be considered a safe and effective procedure in relieving medically refractory vertigo in Menière’s disease, while preserving hearing.

Skin metastases of glioblastoma in the absence of intracranial progression are associated with a shift towards a mesenchymal immunophenotype: report of two cases

Glioblastoma multiforme (GBM) is the most malignantastrocytic tumour. Extra-neural spread is exceedingly rare,and usually develops at the time of intracranial progressionfollowing a surgical procedure [2–4]. Less frequently,metastases are a consequence of spontaneous tumour trans-dural extension or haematogenous spread. Here, wedescribe two unusual cases of GBM in which scalpmetastases appeared in the absence of intracranial diseaseprogression.Case 1A 48-year-old woman who presented with headache,speech disturbances and left facio-brachial paresis under-went magnetic resonance imaging (MRI), which revealed alarge right fronto-parietal mass with peripheral enhance-ment (Fig. 1a). The patient underwent gross total removalof the tumour, and a histopathological diagnosis of GBMwas made. Using immunohistochemistry, the tumour cellswere shown to co-express GFAP (intensely) and vimentin(less extensively). EGFR was positive in all tumour cellsand YKL-40 showed a faint cytoplasmic positivity in about30% of cells (Fig. 3). Conformal radiotherapy and adjuvanttemozolomide (TMZ) followed surgery. After 12 cycles,and in the absence of intracranial disease recurrence,the patient presented with a 2-cm scalp metastasis, closeto, but not contiguous with the surgical scar (Fig. 1b).A complete removal was performed and the diagnosis ofGBM was confirmed. Histologically, the metastasisshowed an infiltrating growth pattern dispersed intofibrotic tissue and consisted of a neoplastic population oflarge pleomorphic cells with a high mitotic index andstrong positivity for vimentin, while the GFAP stainingwas less diffuse than in the intracranial tumour. More-over, when compared with the primary lesion, EGFR wasnegative in the neoplastic cells, whereas a diffuse, intenseYKL-40 immunoreactivity was found (Fig. 3). The patientunderwent focal radiotherapy; 4 months later, an MRIrevealed distant intracranial progression in the righttemporal lobe. The patient received second-line chemo-therapy but soon the progressive intracranial disease ledto the patient’s death.Case 2A 53-year-old woman presented with a 1-month history ofspeech disturbances and facio-brachio-crural right motordeficit and underwent MRI, which showed a left frontalmass with contrast enhancement (Fig. 2a). She underwentcraniotomy with partial resection of the mass, and a diag-nosis of GBM was made. Immunohistochemistry showed adiffuse and intense GFAP reactivity with vimentin co-expression in a few GFAP-positive areas; EGFR positivitywas diffuse, whereas YKL-40 showed weak and focalexpression (Fig. 3). The patient underwent radiotherapyand standard TMZ treatment, and a partial response with a

Treatment of cerebral arterio-venous malformations with laser.

The surgical application of the laser in the treatment of vascular diseases of the brain is based on its characteristic to perform an immediate or delayed modification of the vessel wall either by shrinking the collagenous fibres or by intraluminal thrombosis. Personal researches have been carried out to study the histological modifications of the vessel wall in normal arteries following laser irradiation with Nd:YAG. On this basis we have treated arterio-venous malformations (AVMs) in man. The laser enables radical surgery with a complete preservation of the healthy tissue surrounding the lesion because of reduced manipulation and the absence of intraoperative haemorrhage. Doppler technique and real-time ultrasonography are mostly suitable in the identification of the small deep-seated AVMs localizing the site of the malformation and the reactive glial tissue surrounding the lesion. The main indications are small AVMs located in critical areas of the brain.

The CO2 Laser in Neurosurgery

While in ophthalmology and other branches of surgery (plastic surgery, gynaecology, otorhinolaryngology etc.), the laser has now become part of operative routine, in neurosurgery this has only recently become true and applies to very few medical centres. Thus, the operation by S. Stellar1, 2, 3 in 1969, for the removal of a cerebral glioma, remained for a long time an isolated instance. Heppner and Ascher4 used the laser systematically at the Neurosurgical Clinic of the University of Graz, starting in 1976; Perria in Genoa, also from 1976; and this Institute of Neurosurgery5 of the University of Turin, starting from 1977. We can deduce the limitations and possible counter-indications of the laser from the experience gained at these medical centres, as well as from papers presented at conferences.

New technologies in neurosurgery: Effects on the conventional techniques and anaesthesiological considerations

New technologies have been recently introduced into neurosurgery: laser sources, ultrasonic aspiration, intraoperative echotomography and intraoperative Doppler flowmeter. The aim of this work, showing the use of these instruments in different neurosurgical operations, is to discuss the effective improvements of the surgical techniques when comparing new and traditional technologies. The laser is able to concentrate high energies in restricted areas allowing a maximum selectivity. Having a superficial destructive effect with associated hemostasis, CO2 and argon are suitable in dissection maneuvers. Nd:YAG produces a high thermal diffusion, consenting a deeper and extended tissue removal and a considerable reduction of intraoperative blood loss also in vascularized tumors. A promising field of application of the laser is the treatment of cerebral vascular malformations. In arterio-venous malformations the irradiation of the nidus with Nd:YAG produces a rapid obliteration of the pathologic vessels. This technique avoids the isolation of the feeding arteries and reduces the manipulation of the surrounding tissue. In small saccular aneurysms an argon laser is used to produce a shrinkage of the dilatation with consequent occlusion of the malformation. The ultrasonic aspirator is used in the tumoral surgery to obtain a more rapid demolition of the mass by fragmentation and suction. Intraoperative echotomography consents a sharp topographic localization of the lesion, particularly in deeper cerebral areas, providing data on the nature of solid tumors. The intraoperative Doppler flowmeter is useful for identification of the feeding arteries and the shunt of the small deep-seated arterio-venous malformations consenting a dynamic evaluation of the operation. General anaesthesia in neurosurgical procedures is favourably influenced by laser use. Conventional anaesthetic techniques, however, must be modified to avoid the harmful effect of the laser, depending on the movements of the brain surface, which may switch the laser beam to adjacent tissues, and become particularly dangerous when the laser is used near high functional structures or when the laser is driven by a computer.

Non-invasive high voltage electrical stimulation as a monitoring tool of nerve root function in lumbosacral surgery.

OBJECTIVE To verify the safety and clinical use of non-invasive high-voltage electrical stimulation (HVES) in patients with compressive radiculopathy. To test the feasibility of HVES to survey nerve root function during lumbosacral surgery. METHODS In 20 patients undergoing lumbosacral surgery for degenerative spinal diseases, compound muscle action potentials (CMAPs) evoked by maximal HVES were bilaterally recorded throughout surgery from L3 to S2 radicular territories. A preliminary study was performed in awake patients to rule out detrimental effects caused by HVES. RESULTS Preoperative study confirmed the safety of HVES. Unexpectedly, a transient but significant remission of pain was observed after root stimulation. Intraoperative monitoring (IOM) was accomplished in all patients. HVES never hindered surgical procedures and never caused mechanical damage within the operatory field. In 4 patients acute, highly focal and reversible conduction failure was promptly detected by HVES in radicular territories congruent with the root manipulated at that moment. CONCLUSIONS HVES is a safe and sensitive tool to monitor nerve root function in lumbosacral surgery. SIGNIFICANCE The method is based on the assumption that any acute conduction failure occurring during surgery can be immediately and unambiguously detected by HVES if root stimulation is supramaximal and delivered rostral to the surgical level.

S118. A methodological reappraisal of triggered electromyography for placement of pedicular screw

Introduction Triggered electromyography is widely used in predicting pedicle wall break after placement of pedicle screw instrumentation. However, common experience confirms that the technique fails to detect medial pedicle breaches more often than expected, the occurrence of false negative results being the most unpleasant bias. This probably results from current dispersion via the uninsulated screw and current shunt between the anode and the return electrode, causing an unpredictable discrepancy between the initial current strength and that, always lower, actually reaching the tested root. The purpose of our technique is to correct this misleading mismatch through a strictly focal root stimulation within the pedicle hole, preceding screw insertion. Methods In 28 patients, receiving 138 lumbosacral pedicle screws during instrumented fusion, we performed a focal root stimulation by inserting a monopolar electrode fully insulated except at the tip into the pedicle hole at a depth, customized to the individual patient, ranging from 12 to 16 mm, to make the stimulating tip directly face the tested nerve root. Moreover, to prevent current shunt between the active and return electrode bypassing the tested nerve root, the return electrode was a large (25 cm 2 ) surface electrode placed over the middle abdomen between umbilicus and xiphoid process. In all cases threshold to screw stimulation was also measured. All subjects received a post-op CT scan. Results Threshold values after hole stimulation in all cases in which intra-op visual inspection (when performed), post-op clinical evaluation and CT scan ruled out a pedicle medial wall breakthrough, ranged from 2.7 to 13 mA without significant difference between L4, L5 and S1. Corresponding values for screw stimulation ranged between 9.5 and 44 mA. In 5 of 7 cases of this group with threshold values at the lower range (2.7–3.3 mA), post-op CT scan, showed an apparently intact pedicle wall but a reduced distance (1 and 1.5 mm) from the screw edge to the surface of the pedicle. The four cases in whom CT scan demonstrated a pedicle break had a threshold of 2, 1.5, 2.5 and 1.8 mA, respectively. In the first 2 cases, assuming a false positive result based on an apparently normal intra-op fluoroscopy, screw was inserted, but visual inspection after laminectomy revealed a conflict between root and screw, advising a prompt screw withdrawal and redirection. In the last 2 cases screw insertion was deferred and pedicle hole was redirected. In only 2 of them, threshold to screw stimulation was abnormal (8.4 and 4.8 mA). No false negative results were observed with hole stimulation. Conclusion Focal hole stimulation provides the absolute threshold values for root activation as proved by the fact that after a pedicle wall break, threshold values coincided with those commonly observed after direct root stimulation. Early detection of a misdirected pedicle route may prevent a further damage caused by insertion of the more invasive screw.