Martin Scholsem

Surgical management of anterior cranial base fractures with cerebrospinal fluid fistulae: a single-institution experience.

OBJECTIVE The management of cerebrospinal fluid (CSF) fistulae after anterior cranial base fracture remains a surgical challenge. We reviewed our results in the repair of CSF fistulae complicating multiple anterior cranial base fractures via a combined intracranial extradural and intradural approach and describe a treatment algorithm derived from this experience. METHODS We retrospectively reviewed the files of 209 patients with an anterior cranial base fracture complicated by a CSF fistula who were admitted between 1980 and 2003 to Liège State University Hospital. Among those patients, 109 had a persistent CSF leak or radiological signs of an unhealed dural tear. All underwent the same surgical procedure, with combined extradural and intradural closure of the dural tear. RESULTS Of the 109 patients, 98 patients (90%) were cured after the first operation. Persistent postoperative CSF rhinorrhea occurred in 11 patients (10%), necessitating an early complementary surgery via a transsphenoidal approach (7 patients) or a second-look intracranial approach (4 patients). No postoperative neurological deterioration attributable to increasing frontocerebral edema occurred. During the mean follow-up period of 36 months, recurrence of CSF fistula was observed in five patients and required an additional surgical repair procedure. CONCLUSION The closure of CSF fistulae after an anterior cranial base fracture via a combined intracranial extradural and intradural approach, which allows the visualization and repair of the entire anterior base, is safe and effective. It is essentially indicated for patients with extensive bone defects in the cranial base, multiple fractures of the ethmoid bone and the posterior wall of the frontal sinus, cranial nerve involvement, associated lesions necessitating surgery such as intracranial hematomas, and post-traumatic intracranial infection. Rhinorrhea caused by a precisely located small tear may be treated with endoscopy.

Vagus nerve stimulation in awake rats reduces formalin-induced nociceptive behaviour and fos-immunoreactivity in trigeminal nucleus caudalis

&NA; Besides its well‐established efficacy in epilepsy, vagus nerve stimulation (VNS) may be of potential interest in pain treatment. It has, however, not yet been assessed in animal pain models with the devices and stimulation protocols used in humans. We have therefore studied in awake rats the effects of left cervical VNS on trigeminal nociception using an implantable electrode and stimulator (NCP‐Cyberonics®). VNS was applied for 24 h at 2 mA intensity, 20 Hz frequency, 0.5 ms pulse width and a duty cycle of 20 s ON/18 s OFF. As a nociceptive stimulus, we injected formalin into the left mystacial vibrissae, assessed behaviour for 45 min and sacrificed the animals 45 min later. Fos‐immunoreactive (Fos‐Ir) neurons were counted in laminae I–II of trigeminal nucleus caudalis (TNC) on both sides. We used three groups of control animals: VNS without formalin, formalin without VNS and sham VNS (implanted without stimulation or formalin). Whereas sham VNS had no significant effect, VNS alone increased Fos expression in ipsilateral TNC in addition to the expected increase in nucleus tractus solitarius. It also significantly attenuated the increase of Fos‐Ir neurons observed in ipsilateral TNC laminae I–II after formalin injection. If the proper VNS effect on Fos‐expression was subtracted, the reduction of formalin‐induced nociceptor activation was 55%. VNS also reduced nociceptive behaviour on average by 96.1% during the early phase (0–6 min) and by 60.7% during the late phase (6–45 min) after the formalin injection. These results suggest that VNS applied with a device used in human therapy may have in awake rats a significant antinociceptive effect in a model of trigeminal pain.

Vagus nerve stimulation attenuates heat- and formalin-induced pain in rats

The analgesic effect of vagus nerve stimulation (VNS) has not yet been demonstrated in animals with the devices used in the clinic. We studied in awake rats the effects of two VNS protocols on the hind paw hot water test and compared the results with those previously obtained in the oro-facial formalin test. A stringent duty cycle (20 s on/18 s off) increased heat pain tolerance in both hind paws (average 188%) after 2 h of stimulation. VNS with parameters used in epilepsy (30 s on/5 min off) decreased heat tolerance after 2 h, but produced a significant antinociceptive effect after days of stimulation. VNS may thus be useful in pain disorders, even with the less stringent protocol.

Acquired tonsillar herniation and syringomyelia after pleural effusion aspiration: case report.

OBJECTIVE We present a case of brachial plexus avulsion and reconstructive surgery with cerebrospinal fluid leak between the cervical subarachnoid space and the pleural cavity responsible for tonsillar herniation and syringomyelia. CLINICAL PRESENTATION A 17-year-old man presented with headaches when he was positioned upright, simultaneously with a persistent right pleural effusion for about 4 months after reconstructive surgery for a right brachial plexus avulsion. In addition, the headaches had worsened considerably after two aspirations of the pleural effusion. Magnetic resonance imaging (MRI) demonstrated signs of chronic intracranial hypotension and tonsillar herniation with a presyrinx cavity from vertebral level C1 to C7. None of those abnormalities were seen on the MRI scan obtained a few days after the initial trauma 7 months previously. Plexus brachial MRI confirmed the presence of a cerebrospinal fluid leak between the avulsed root of C8 and the pulmonary apex. INTERVENTION The leak was treated by surgical closure of the dural tear of the C8 root. Postoperatively, the patients headaches immediately resolved, and MRI 4 months later showed resolution of cerebellar tonsil herniation and regression of the syrinx. CONCLUSION Resolution of acquired tonsillar herniation and syringomyelia can be achieved by closure of the dural tear responsible of the cerebrospinal fluid leak.

Multifocal choroid plexus papilloma: a case report.

BACKGROUND Multiple choroid plexus papillomas (CPPs) are rare. Usually, they correspond to villous hypertrophy or metastasis occurring during cerebrospinal dissemination. Multiple CPPs have rarely been reported as synchronous tumors. CASE REPORT Three synchronous CPPs were resected in a 59-year-old female 6 years after their first imaging description. Pathology showed mucus-producing CPP in all 3, 1 of the 3 presenting some signs of atypia. No p53 or hSNF5/INI1 mutation, or signs of polyoma viruses infection were found. CONCLUSION Although no clear cause for the multifocality was found, the simultaneous presence of the three tumors and their benign histology suggest that they were synchronous and not metastatic. The issue of differentiating synchronous CPPs from metastatic CPP is discussed.

Solitary fibrous tumour of the vagus nerve

Abstract We describe the complete removal of a foramen magnum solitary fibrous tumour in a 36-year-old woman. It originated on a caudal vagus nerve rootlet, classically described as the ‘cranial’ accessory nerve root. This ninth case of immunohistologically confirmed cranial or spinal nerve SFT is the first of the vagus nerve.