Elie Samaha

Multifocal meningeal melanocytoma: a new pathological entity or the result of leptomeningeal seeding?

Meningeal melanocytoma is a rare benign CNS tumor derived from the leptomeningeal melanocytes. Although unusual, malignant transformation with leptomeningeal seeding into the brain or spinal cord may occur years after the initial diagnosis. The authors report a unique case of multifocal benign meningeal melanocytoma involving both cerebellopontine angles and the thoracic spinal cord, with associated diffuse leptomeningeal hyperpigmentation. They review the literature relevant to this topic and discuss the radiological and pathological features of this disease as well as its treatment options.

Impact of the lunar cycle on the incidence of intracranial aneurysm rupture: Myth or reality?

OBJECTIVE To analyze the impact of the lunar cycle and season on the incidence of aneurysmal subarachnoid hemorrhage (SAH). PATIENTS AND METHODS The medical records of 111 patients who were admitted over a 5-year period to our department because of aneurysmal SAH were retrospectively reviewed. The date of aneurysm rupture was matched with the corresponding season and moon phase. RESULTS An incidence peak for aneurysm rupture (28 patients) was seen during the phase of new moon, which was statistically significant (p < 0.001). In contrast, no seasonal variation in the incidence of SAH was observed. CONCLUSION The lunar cycle seems to affect the incidence of intracranial aneurysm rupture, with the new moon being associated with an increased risk of aneurysmal SAH.

What happens to Modic changes following lumbar discectomy? Analysis of a cohort of 41 patients with a 3- to 5-year follow-up period

OBJECT The natural history of Modic changes (MCs) in the lumbar spine is often marked by conversion from one type to another, but their course following lumbar discectomy remains unknown. The authors sought to study the impact of surgery on the natural history of these lesions. METHODS Forty-one patients treated with lumbar microdiscectomy between 2004 and 2005 were enrolled in this study and underwent clinical evaluation and repeat MR imaging after a median follow-up of 41 months (range 32-59 months). Preoperative and follow-up MR images were reviewed and the type, location, and extent of MCs at the operated level were recorded and compared. RESULTS The study population consisted of 27 men and 14 women with a mean age of 54 years (range 24-78 years). During the follow-up period, the prevalence of MCs increased from 46.3% to 78%, and 26 patients (63.4%) had Type 2 lesions at the operated level. Of the 22 patients without MCs, 4 (18.2%) converted to Type 1 and 9 (40.9%) to Type 2. Of the 5 Type 1 lesions, 3 (60%) converted to Type 2, and 2 (40%) remained Type 1 but increased in size. In contrast, none of the 14 Type 2 changes converted to another type, although 10 (71.4%) increased in extent. There were no reverse conversions to Type 0. CONCLUSIONS Following lumbar discectomy, most patients develop Type 2 changes at the operated level, possibly as a result of accelerated degeneration in the operated disc. Neither the preoperative presence of MCs nor their postoperative course appears to affect the clinical outcome.

Surgical treatment of ruptured anterior circulation aneurysms: comparison of pterional and supraorbital keyhole approaches.

BACKGROUND Recent advancements in microsurgical techniques and instrumentation have allowed the development of the keyhole approach in aneurysm surgery. OBJECTIVE To compare the safety, efficacy, and 1-year clinical outcome of supraorbital keyhole and standard pterional approaches for ruptured anterior circulation aneurysms. METHODS A total of 87 patients underwent surgical clipping, 40 through the pterional and 47 through the supraorbital keyhole approach. Baseline demographics, operative time, procedural complications, and 1-year patient outcome were retrospectively compared. RESULTS The 2 groups were comparable with respect to baseline characteristics, with the exception of a higher proportion of small aneurysms (<7 mm) in the supraorbital group (70.2% vs. 37.5%, P = .002). Total operative time was significantly shorter in the supraorbital group (205 minutes, P < .001) compared with the pterional group (256 minutes). The rate of procedural complications was lower in patients treated through the pterional (17.5%) vs the supraorbital approach (23.4%, P = .4). Intraoperative aneurysm ruptures occurred more frequently in the supraorbital group (10.6% vs. 2.5%). No patient experienced early or late rebleeding in either group. One year after treatment, 75% (30/40) of patients achieved a favorable outcome (Glasgow outcome scale IV or V) in the pterional group vs 76.6% (36/47) in the supraorbital group (P = .8). CONCLUSION The rate of procedural complications may be higher with the supraorbital keyhole approach, but overall patient outcomes appear to be comparable. The pterional approach is a simple, reliable, and efficient procedure. The keyhole approach may be an acceptable alternative for neurosurgeons who have gained sufficient experience with the technique, especially for small noncomplex aneurysms.

Schwannoma of the Tentorium Cerebelli in a Child

Intracranial schwannomas not arising from a cranial nerve are very rare. Schwannomas of the dura are even rarer; in the literature, we found only two cases: a schwannoma of the falx and one of the torcula. We report a third case of a 9-year-old girl with a schwannoma of the tentorium cerebelli. The different theories concerning the origin of this tumor in this particular location are discussed.

Neurocytome central: À propos de quatre cas

Resume Nous rapportons 4 cas de neurocytomes traites a l’Hotel-dieu de France a Beyrouth entre 1994 et 2002. Il s’agit d’une tumeur ventriculaire benigne du sujet jeune a differenciation neuronale. Elle se revele le plus souvent par un tableau d’hypertension intracrânienne. Le diagnostic histologique peut parfois se montrer difficile, necessitant le recours aux techniques d’immunomarquage. Le traitement de choix est la resection chirurgicale complete. Le pronostic est le plus souvent excellent (cas n° 1 et 2). Toutefois, meme apres une exerese totale, certaines tumeurs peuvent recidiver (cas n° 3). Dans de rares cas (cas n° 4), cette tumeur peut avoir un comportement agressif, necessitant le recours a des traitements complementaires. La prise en charge des recidives ou des residus sera discutee.

Endoscopic Third Ventriculostomy: The Lebanese Experience

Background: Endoscopic third ventriculostomy (ETV) has gained wide popularity as a first-line treatment for obstructive hydrocephalus (OHC). We have been performing ETV since 1998. We report our experience with this technique in the management of OHC. Methods: Between 1998 and 2007, we performed 49 ETV procedures in 46 patients suffering from OHC. Medical records were retrospectively reviewed. Success was defined as shunt-free survival. Results: There were 29 males and 17 females with a mean age of 23 years (6 months–65 years). Aqueductal stenosis and tectal tumor were the most common etiologies (63%). Seven patients (15.6%) had early ETV failure. Of 38 patients with initial success and available follow-up, shunt independence was achieved in 29 patients (76.3%) after a mean follow-up of 37 months. Kaplan-Meier analysis yielded a 70% 5-year shunt-free survival rate. On multivariate analysis, no variables could predict early or late ETV failure. Transient complications occurred in 6 patients (13%), but there were no ETV-related deaths or permanent morbidity. Conclusion: ETV is a safe and effective treatment for OHC, resulting in a high rate of long-term shunt independence with a low risk of complications. ETV should be considered the treatment of choice for patients with OHC and its development as a substitute to shunt placement should be encouraged in neurosurgically developing countries.

Dural arteriovenous malformation: an unusual cause of trigeminal neuralgia.

SummaryTrigeminal neuralgia has been rarely reported in association with dural arteriovenous malformations (DAVMs). We describe a case of trigeminal neuralgia resulting from compression of the trigeminal nerve at its root entry zone by a large tentorial DAVM. Surgical interruption of the draining vein at its exit from the tentorium resulted in complete angiographic obliteration of the fistula with immediate resolution of the facial pain. We review the literature relevant to this topic and discuss the aetiology and pathophysiology of trigeminal neuralgia as well as the management of tentorial DAVMs.

Pathological effects and motor response threshold changes following radiofrequency application at various distances from the L-5 nerve root: an experimental study

OBJECT Radiofrequency (RF) ablation is a minimally invasive technique often used percutaneously in the treatment of many conditions such as spasticity, pain, and osteoid osteoma. The purpose of this study was to assess the value of motor response threshold (MRT) as an indirect indicator of the RF generators electrode to nerve distance, and to evaluate the effects of RF at various distances from a nervous structure. METHODS The L-5 nerve root was studied in 102 Sprague-Dawley rats (sham contralateral side). Motor response thresholds at 0, 2, 4, 5, and 6 mm from the nerve root were assessed before and after RF application for 2 minutes at 80° C on Days 0 and 7. Radiofrequency was applied 0, 2, 4, 5, and 6 mm away from L-5 and with the addition of interposed cortical bone. The effects of RF application on MRT were studied, and subsequent nerve injury was evaluated using light microscopy pathological examination. RESULTS There is a significant correlation between MRT and the distance between the electrode tip and L-5, with MRT less than 0.5 V when the electrode was in direct contact with the root. Electrical and pathological changes following RF application were more pronounced at 0 mm, with worsening seen on Day 7. Radiofrequency at 2 and 4 mm produced fewer electrical and histological deleterious effects on the nerve on Days 0 and 7, with an obvious improvement on Day 7. At 5 mm, electrical and histological abnormalities were minimal on Day 0 and were fully reversible on Day 7. At 6 mm and with interposed cortical bone, MRT and pathological findings were unchanged on Days 0 and 7. CONCLUSIONS The MRT proved to be a useful and reliable tool in decreasing nerve morbidity following RF ablation in animals and may be used in humans for the same purpose. It serves as an indirect indicator of the proximity of the RF generators electrode tip to any adjacent motor nervous structure. A minimum safe distance of 5 mm between the electrode tip and the nerve is required to avoid irreversible nerve injury, unless a bony wall is interposed between them, thus serving as a nerve shield. In medical conditions that require RF ablation of the nerve, such as spasticity and pain, the MRT must be lower than 0.5 V. When a nerve lesion is to be avoided such as in cases of osteoid osteoma, an MRT higher than 2.5 V is considered safe, reflecting a distance greater than 5 mm.

Lumbar microdiscectomy: a clinicoradiological analysis of outcome.

BACKGROUND The long-term outcome after lumbar microdiscectomy (LMD) may be affected by low back pain (LBP) and segmental instability, the determinants of which remain unclear. We sought to analyze the interaction between clinical, functional, and radiological variables and their impact on patient outcome. METHODS All patients who underwent LMD in 2004-2005 were invited to participate in this retrospective cohort study. Patients were re-evaluated clinically and radiologically after a three to five year follow-up. RESULTS Forty-one of 97 eligible patients were enrolled. Twelve patients (29.3%) reported moderate-to-severe sciatica, 12 (29.3%) had moderate LBP, and 13 (31.7%) exhibited clinical evidence of segmental instability. Thirty-eight patients (92.7%) had minimal disability and 3 (7.3%) had moderate disability. Twenty-three patients (56.1%) were fully satisfied, while 18 (43.9%) had only partial satisfaction, having expected a better outcome. Thirty-three patients (80.5%) returned to full-time work. Median disc space collapse (DSC) was 20% (range 5-66%) and L4-L5 was particularly affected. Prevalence of Modic changes increased from 46.3% to 78% with type 2 predominance. Multivariate logistic regression analysis identified the following negative prognostic factors: female sex, young age, lack of regular exercise, and chronic preoperative LBP. There was no correlation between the course of Modic changes, DSC, and patient outcome. CONCLUSION Although many patients may be symptomatic following LMD, significant disability and dissatisfaction are uncommon. Female sex, young age, lack of exercise, and chronic preoperative LBP may predict a worse outcome. Disc collapse is a universal finding, particularly at L4-L5. Neither DSC nor Modic changes seem to affect patient outcome.