Cormac O. Maher, John L. D. Atkinson, and John I. Lane
✓ The authors report on an arteriovenous malformation (AVM) within the trigeminal nerve in an otherwise healthy 76-year-old man who presented with the sudden onset of headache and ataxia. The AVM was totally resected via a lateral sub-occipital approach to the cerebellopontine angle. Dural arteriovenous fistulas and AVMs of the dorsal root entry zone and adjacent brainstem that compress the trigeminal nerve have been previously described. To the authors' knowledge, this is the first reported case of an angiographically, surgically, and pathologically proven AVM arising from within the trigeminal nerve itself.
Robert J. Spinner, John L. D. Atkinson, and Robert L. Tiel
Object. Based on a large multicenter experience and a review of the literature, the authors propose a unifying theory to explain an articular origin of peroneal intraneural ganglia. They believe that this unifying theory explains certain intriguing, but poorly understood findings in the literature, including the proximity of the cyst to the joint, the unusual preferential deep peroneal nerve (DPN) deficit, the absence of a pure superficial peroneal nerve (SPN) involvement, the finding of a pedicle in 40% of cases, and the high (10–20%) recurrence rate.
Methods. The authors believe that peroneal intraneural lesions are derived from the superior tibiofibular joint and communicate from it via a one-way valve. Given access to the articular branch, the cyst typically dissects proximally by the path of least resistance within the epineurium and up the DPN and the DPN component of the common peroneal nerve (CPN) before compressing nearby SPN fascicles. The authors present objective evidence based on anatomical, clinical, imaging, operative, and histological data that support this unifying theory.
Conclusions. The predictable clinical presentation, electrical studies, imaging characteristics, operative observations, and histological findings regarding peroneal intraneural ganglia can be understood in terms of their origin from the superior tibiofibular joint, the anatomy of the articular branch, and the internal topography of the peroneal nerve that the cyst invades. Understanding the controversial pathogenesis of these cysts will enable surgeons to perform operations based on the pathoanatomy of the articular branch of the CPN and the superior tibiofibular joint, which will ultimately improve clinical results.
John L. D. Atkinson and John I. Lane
✓ Peritumoral edema surrounding meningiomas is poorly understood; however, several theories have been proposed in the literature. A case is presented here of a frontal sagittal meningioma symmetrically effacing both frontal lobes that subsequently evokes peritumoral edema on only one side. The tumor is histologically identical on the left and right sides. Angiograms were obtained that support previous work, which suggests that the degree of cortical parasitization of blood supply correlates with peritumoral edema whether or not tumor secretory factors are involved.
Frederic P. Collignon, Jonathan A. Friedman, and John L. D. Atkinson
Wouter I. Schievink, Fredric B. Meyer, John L. D. Atkinson, and Bahram Mokri
✓ Spinal cerebrospinal fluid (CSF) leaks are often implicated as the cause of the syndrome of spontaneous intracranial hypotension, but they have rarely been demonstrated radiographically or surgically. The authors reviewed their experience with documented cases of spinal CSF leaks of spontaneous onset in 11 patients including their surgical observations in four of the patients.
The mean age of the six women and five men included in the study was 38 years (range 22–51 years). All patients presented with a postural headache; however, most had additional symptoms, including nausea, emesis, sixth cranial-nerve paresis, or local back pain at the level of the CSF leak. All patients underwent indium-111 radionucleotide cisternography or computerized tomographic (CT) myelography. The location of the spontaneous CSF leak was in the cervical spine in two patients, the cervicothoracic junction in three patients, the thoracic spine in five patients, and the lumbar spine in one patient. The false negative rate for radionucleotide cisternography was high (30%). Subdural fluid collections, meningeal enhancement, and downward displacement of the cerebellum, resembling a Chiari I malformation, were commonly found on cranial imaging studies. In most patients, the symptoms resolved in response to supportive measures or an epidural blood patch. Leaking meningeal diverticula were found to be the cause of the CSF leak in four patients who underwent surgery. In three patients these diverticula could be ligated with good result but in one patient an extensive complex of meningeal diverticula was found to be inoperable. Two patients had an unusual body habitus and joint hypermobility, and two other patients had suffered a spontaneous retinal detachment at a young age.
In conclusion, spontaneous spinal CSF leaks are uncommon, but they are increasingly recognized as a cause of spontaneous intracranial hypotension. Most spinal CSF leaks are located at the cervicothoracic junction or in the thoracic spine, and they may be associated with meningeal diverticula. The radiographic study of choice is CT myelography. The disease is usually self-limiting, but in selected cases our experience with surgical ligation of leaking meningeal diverticula has been satisfactory. An underlying connective tissue disorder may be present in some patients with a spontaneous spinal CSF leak.
John L. D. Atkinson, Jan L. Kasperbauer, E. Meredith James, John I. Lane, and Todd B. Nippoldt
✓ Ultrasonography has been used in neurosurgical operative procedures for several decades. The authors report the case of a large pituitary tumor that was subtotally resected using endoscopy via the transnasal—transsphenoidal approach, with the aid of transcranial real-time ultrasound. To our knowledge, this is the first reported case in which intraoperative transcranial—transdural real-time ultrasound was used to facilitate the resection of a skull base tumor.
John L. D. Atkinson, John I. Lane, Harold J. Colbassani, and D. Mark E. Llewellyn
✓ The case is presented of a 23-year-old man suffering ischemic brain infarction from spontaneous thrombosis of a left posterior cerebral artery P1–P2 junction aneurysm. Vasospasm and/or partial parent vessel occlusion were documented by magnetic resonance (MR) imaging and angiography. Repeat cerebral angiography and MR imaging 3 months later revealed patency of the posterior cerebral artery and luminal filling of a 1-cm fusiform aneurysm, which was successfully trapped at surgery.