Gustavo Touzet

Exhaustive, one-year follow-up of subthalamic nucleus deep brain stimulation in a large, single-center cohort of parkinsonian patients.

OBJECTIVE To prospectively assess the impact of subthalamic nucleus (STN) deep brain stimulation (DBS) at 12 months after surgery in a series of 100 consecutive patients treated in a single center. The primary objective was to describe the clinical outcome in terms of efficacy and tolerance in STN-DBS patients. A secondary objective was to discuss presurgery clinical characteristics a posteriori as a function of outcome. METHODS One hundred and three consecutive patients with severe Parkinsons disease received bilateral STN-DBS in our clinic between May 1998 and March 2003. Clinical assessment was performed before and 12 months after surgery and was based on the Unified Parkinsons Disease Rating Scale, Parts II, III, and IV A; the Schwab and England Scale; and cognitive evaluation. Patient-rated overall improvement was also evaluated. RESULTS Twelve months after surgery, the Unified Parkinsons Disease Rating Scale Part III score decreased by 43%, the Unified Parkinsons Disease Rating Scale Part II score (activities of daily living) fell by 34%, and the severity of dyskinesia-related disability decreased by 61%. The main surgical complications after STN-DBS were as follows: infection (n = 7), intracerebral hematoma (n = 5), electrode fracture (n = 4), and incorrect lead placement (n = 8). We observed cognitive decline and depression in 7.7 and 18% of the patients, respectively. The mean patient-rated overall improvement score was 70.7%. CONCLUSION The efficacy and safety of STN-DBS in our centers large cohort of Parkinsonian patients are generally similar to the results obtained by other groups, albeit at the lower limit of the range of reported values. In contrast to efficacy, the occurrence of adverse events cannot be predicted. Younger patients with Parkinsons disease (i.e., those younger than 60 yr) often show an excellent response to levodopa. However, in view of our data on overall patient satisfaction and the occurrence of adverse events, we suggest that older patients (but not those older than 70 yr) and less dopa-sensitive patients (but not those with a response <50%) should still be offered the option of STN-DBS.

Role of radiosurgery in the management of cerebral arteriovenous malformations in the pediatric age group: data from a 100-patient series.

OBJECTIVETo assess the safety and efficacy of radiosurgery for the management of arteriovenous malformations (AVMs) in the pediatric age group. METHODSWe reviewed data from 100 children (44 girls and 56 boys) presenting a total of 103 AVMs treated by linear accelerator radiosurgery between December 1988 and May 2002. The median patient age was 12 years (range, 2–16 yr). Sixty-seven AVMs (65%) were in functional locations and 30% were inoperable. The mean AVM volume was 2.8 cm3 (range, 0.9–21.3 cm3). The mean marginal dose was 23 Gy (range, 15–25 Gy) and required between one and four isocenters. Fifty patients received multimodal treatments with embolization and/or surgery before and/or after radiosurgery. Given that 16 patients underwent two sessions of radiosurgery and one patient received three sessions, a total of 119 radiosurgical treatments were delivered. We maintained our clinical and angiographic follow-up for at least 36 months after irradiation or until the complete obliteration of the AVM was confirmed by angiography (our sole end point for judging clinical efficacy). Univariate and multivariate analysis were performed to determine predictive factors for obliteration. RESULTSComplete obliteration was achieved for 72 AVMs (70%). The permanent neurological deficit rate was 5%. One patient died because of rebleeding. None of our patients presented bleeding after an angiographically verified AVM obliteration. The main predictive factors for obliteration were low AVM volume and no previous embolization. Moreover, the younger the patient, the more effective the radiosurgery seemed to be. CONCLUSIONRadiosurgery is a safe and effective treatment for AVMs in the pediatric age group. One criterion for success was the use of a prescription dose similar to that used with adult populations.

Clinical outcomes after Gamma Knife surgery for idiopathic trigeminal neuralgia: review of 76 consecutive cases

OBJECT Stereotactic radiosurgery is an increasingly used, and the least invasive, surgical option for patients with trigeminal neuralgia (TN). In this study, the authors performed a retrospective evaluation of the safety and efficacy of this method for idiopathic TN. METHODS The authors reviewed data from 76 patients with idiopathic TN who underwent Gamma Knife surgery (GKS). The mean age of the patients was 64 years (range 27-83 years). All patients had typical features of TN. Thirty patients (39.5%) had previously undergone surgery. The intervention consisted of GKS on the retrogasserian cisternal portion of the fifth cranial nerve. The mean maximum GKS dose used was 85.1 Gy (range 75-90 Gy). RESULTS Patients were followed-up from 6 to 42 months (mean 20.3 months) after GKS. Complete pain relief was achieved in 83.1% of the patients within 1 year, 70.9% within 2 years, and 62.5% within 3 years. Patients who underwent previous surgery demonstrated a lower rate of pain relief (p < 0.05). Twenty patients (26.3%) reported pain recurrence between 6 and 42 months after treatment. New or worsened persistent trigeminal dysfunction developed after GKS in 16 patients (21%); 8 of these patients described some facial numbness/not bothersome, and 8 reported some facial numbness/somewhat bothersome. None of the patients developed troublesome dysesthesia or anesthesia dolorosa. CONCLUSIONS Gamma Knife surgery for idiopathic TN proved to be safe and effective and was associated with a particularly low rate of complications.

MANAGEMENT OF CYSTIC CRANIOPHARYNGIOMAS WITH STEREOTACTIC ENDOCAVITARY IRRADIATION USING COLLOIDAL 186RE : A RETROSPECTIVE STUDY OF 48 CONSECUTIVE PATIENTS

OBJECTIVE We retrospectively reviewed the results of stereotactic endocavitary irradiation with colloidal 186Re in the treatment of cystic craniopharyngiomas. METHODS Among 54 consecutive patients included in a 186Re stereotactic endocavitary irradiation procedure, 42 patients (29 male and 13 female; average age, 38.7 years) received therapeutic injection via intracystic catheter introduced under stereotactic conditions. The mean follow-up period was 43 months (range, 8–148 months). Endocavitary irradiation was the primary treatment for 15 patients and an adjuvant treatment for 27 patients. The mean volume before irradiation was 8.07 mm3, and the mean radiation dose was 381 MBq. RESULTS Cystic mean volume after irradiation was 2.6 cm3 (P < 0.001 with initial volume). The retraction of the cyst was complete for 17 patients (44%) and partial for 17 (44%). In partial retraction, cystic volume decreased more than 50% for 12 (3%) patients and less than 25% (13%) for 5. Cystic volume remained the same or increased for 5 (13%) patients. Concerning visual functions, 12 (44.5%) patients improved and 2 worsened, despite tumor control. No endocrinological deterioration occurred. Among 17 patients with preoperative cognitive dysfunction, 10 improved and 6 had no change. One patient showed memory alteration 4 months after stereotactic endocavitary irradiation despite cyst volume reduction. No mortality occurred. CONCLUSION 186Re stereotactic endocavitary irradiation for the treatment of cystic craniopharyngiomas is a safe and effective procedure with a tumor control rate greater than 70%. This treatment can be used for first-intention treatment of pure cystic craniopharyngiomas or for second-intention treatment of cystic recurrences.

Correlation between magnetic resonance imaging findings and histological diagnosis of intrinsic brainstem lesions in adults

Management of brainstem mass lesions remains a controversial issue, especially when the lesion cannot be excised and when infiltration occurs; moreover, the benefits of a stereotactic procedure are still under debate. In most studies, treatment decisions are based solely on MRI features and do not include a histopathological diagnosis. In the current study, we compared MRI characteristics with histopathological findings of intrinsic brainstem lesions and identified the characteristics associated with the diagnosis of pathologies other than diffuse glioma. From February 1988 through August 2007, 96 brainstem biopsies were performed at the Roger Salengro Hospital in Lille, France, on adult patients with intrinsic brainstem lesions not amenable to excision. Of the 96 patients, 42 were women and 54 were men, with a mean age of 41 years (range, 18-75 years). Data analysis of the MRI findings revealed focal (P < .05) and contrast enhancing lesions (P < .05), and these lesions were significant factors associated with the diagnosis of pathologies other than diffuse glioma. Focal lesions were a significant factor associated with a diagnosis of nontumor lesions (P < .05). In conclusion, the diagnostic effect of stereotactic biopsy on intrinsic brainstem lesions was greater in patients with focal or enhancing lesions shown by MRI, in whom the diagnosis of diffuse glioma was less frequent.

Stereotactic robot-guided biopsies of brain stem lesions: Experience with 15 cases

BACKGROUND AND PURPOSE Biopsies of brain stem lesions are useful for histopathological analysis, which guide appropriate treatment. The frame-based stereotactic procedure is the gold standard technique for biopsies of the brain stem. For the past few years, a frameless stereotactic robot, the NeuroMate robot (Renishaw, UK) has also been used for brain biopsies. We report a retrospective study of 15 patients who underwent NeuroMate robot-guided biopsies of brain stem lesions to evaluate the efficiency and safety of the system. METHODS From January 2004 to March 2006, 15 patients (five children and ten adults) underwent 17 biopsies of brain stem lesions. The lesions were located in the mesencephalon in two cases, in the pons in seven cases, in the pons and the medulla oblongata in five cases, and in the whole midbrain in one case. The biopsy procedure comprised four stages: image acquisition, preoperative planning, patient-to-image registration, and operative procedure. A transcerebellar approach was used in 12 cases and a double oblique anterior frontal approach in five cases. RESULTS Two adults underwent a second procedure because the first biopsy was not contributive. There was no operative mortality. We observed two cases of transient morbidity and one case of permanent morbidity. CONCLUSIONS The frameless NeuroMate robot is an efficient and safe instrument for biopsies of brain stem lesions. We believe that the use of frameless stereotactic techniques for brain stem biopsies could increase the number of biopsies and therefore improve the diagnostic yield and accuracy of the technique.

Stereotactic biopsy for brainstem tumors: comparison of transcerebellar with transfrontal approach.

Background: An important aspect of evaluating patients submitted to stereotactic biopsy of the brainstem is the trajectory used. The literature describes two principal approaches: the suboccipital transcerebellar and the transfrontal; however, no studies exist comparing these two techniques. Objective: The purpose of this study was to compare diagnosis success rates and complications between the suboccipital transcerebellar and transfrontal trajectories. Methods: The study evaluated 142 patients submitted to stereotactic biopsy. The patients presented brainstem tumors in the following areas: pons (n = 31), midbrain (n = 36), medulla (n = 2), pons-medulla (n = 30), pons-midbrain (n = 33), and midbrain-pons-medulla (n = 10). On 123 patients, the transfrontal approach was used, and on 19 the suboccipital transcerebellar approach. Results: Comparing success rates between the two approaches, it was observed that in the group of patients submitted to the transfrontal approach, 95.1% (117 cases) were successful, while in those submitted to the suboccipital transcerebellar approach, 84.2% (16 cases) were successful. Despite a higher success rate among patients in the first group, the difference was not statistically significant. Regarding complications, in patients who were biopsied via the transfrontal trajectory, the morbidity rate was 9.8% (12 cases), while in patients submitted to the suboccipital transcerebellar approach, the morbidity rate was 5.3% (1 case) and the mortality rate 5.3% (1 case). Conclusions: This study verified a higher diagnosis rate in patients submitted to the transfrontal approach than in those submitted to the suboccipital transcerebellar approach (95.1 vs. 84.2%); however, the difference was not statistically significant. Regarding complications, the rate was similar in both groups of patients.

Diffuse brainstem glioma: prognostic factors

OBJECT Brainstem gliomas were regarded as a single entity prior to the advent of MRI; however, several studies investigating MRI have recognized that these lesions are a heterogeneous group, and certain subgroups have a better prognosis for long-term survival. The aim of this study was to conduct a retrospective analysis of prognostic factors of patients with brainstem gliomas confirmed by histopathological diagnosis, particularly regarding assessment of whether histological grade, age, and MRI findings are prognostic factors for patient survival. METHODS The study evaluated 100 patients diagnosed with brainstem glioma. There were 63 adults (40 men and 23 women; age range 18-75 years, mean 41 years) and 37 children (19 boys and 18 girls; age range 2-12 years, mean 6.9 years). RESULTS The mean overall survival of this population, measured from the date of biopsy, was 57 months for diffuse low-grade glioma and 13.8 months for diffuse high-grade glioma (p < 0.001). The mean survival among patients with nonenhancing contrast lesions on MRI was 54.2 months, whereas for patients with enhancing lesions, it was 21.7 months (p < 0.001). Comparisons between the Kaplan-Meier survival curves of adults and children revealed similar median survival periods of 25 and 16 months, respectively (p > 0.05). The multivariate analysis (Cox proportional hazards regression) revealed that only histological grade was a significant prognostic factor (p < 0.001). CONCLUSIONS The study revealed that histological grade and MRI features were significant prognostic factors for survival in these patients, but in multivariate analysis, only histological grade remained a significant factor.

Correlation among magnetic resonance imaging findings, prognostic factors for survival, and histological diagnosis of intrinsic brainstem lesions in children.

OBJECT The aim of this study was to compare MR imaging characteristics with histopathological findings of intrinsic brainstem lesions and also to show the prognostic factors in patients with diffuse brainstem glioma. METHODS Between February 1988 and August 2007, 44 brainstem biopsies were performed at the Roger Salengro Hospital in Lille, France, in children with intrinsic brainstem lesions not amenable to excision. Twenty-six were female and 18 male, and the mean age was 6 years. RESULTS Histological evaluation revealed diffuse brainstem glioma in all patients with diffuse nonenhancing brainstem lesions. Diffuse brainstem glioma was found in 18 patients (90%) with diffuse enhancing brainstem lesions. Pathological entities different from diffuse glioma were verified in 2 patients (10%)-1 with ependymoma and 1 with ganglioglioma. In 4 of 5 patients with a focal nonenhancing brainstem lesion, the histopathological diagnosis was diffuse low-grade glioma. In 6 of 10 patients with focal enhancing brainstem lesion, the diagnosis was diffuse brainstem glioma, and pathological entities different from diffuse brainstem glioma were verified in 2 (20%), both with pilocytic astrocytoma. The mean 1-year actuarial survival rates for patients classified with low-grade and high-grade glioma were 80.4% ± 0.08% and 48.6% ± 0.14%, respectively. CONCLUSIONS The impact of stereotactic biopsy on intrinsic brainstem lesions was greater in patients with MR imaging-documented enhancing lesions in whom the diagnosis of diffuse glioma was less frequent. Patients with low-grade glioma seem to have longer survival than those with high-grade glioma.

Motor cortex electric stimulation for the treatment of neuropathic pain

OBJECTIVE Motor cortex stimulation (MCS) is considered to be an effective treatment for chronic neuropathic pain. The aim of the present study was to assess the efficacy of MCS for treating neuropathic pain. METHOD 27 patients with chronic neuropathic pain were operated. Electrodes were implanted with the use of an stereotactic frame. Electrophysiological evaluations (motor stimulation and somatosensory evoked potentials) were performed, with guidance by means of three-dimensional reconstruction of magnetic resonance images of the brain. 10 patients (37%) presented central neuropathic pain (post-stroke pain) and 17 others (63%) presented peripheral neuropathic pain (brachial plexus avulsion, phantom limb pain or trigeminal pain). RESULTS In 15 patients (57.7%) the pain relief was 50% or more; while in ten patients (38.5%), more than 60% of the original pain was relieved. No differences were found in relation to central and peripheral neuropathic pain (p=0.90), pain location (p=0.81), presence of motor deficit (p=0.28) and pain duration (p=0.72). No major complications were observed. CONCLUSION MCS was efficient for treating patients presenting chronic central or peripheral neuropathic pain.