Ulrich Batzdorf

Posterior fossa volume and response to suboccipital decompression in patients with Chiari I malformation.

Smaller posterior fossa (PF) volume has been suggested to be one of the mechanisms responsible for tonsillar herniation through the foramen magnum in patients with Chiari I malformation (CM I). Although previous radiological analyses of the cranial anatomy have suggested a smaller PF volume in patients with CM I, the relationship of the PF volume to decompressive surgery has not been reported. We have measured the ratio of PF volume to supratentorial volume (PF ratio [PFR]) in 20 patients with CM I and 20 control patients by retrospectively studying their magnetic resonance images with a computerized image analyzer. The mean PFR in patients with CM I (with or without syringomyelia) was significantly smaller than for those in the control group (15.6 +/- 1.9 versus 17.5 +/- 1.2, P = 0.0008). Although PFR did not correlate with the extent of tonsillar herniation in patients with CM I, it did directly correlate with their age, i.e., younger patients with CM I (but not control patients) had smaller PFRs. All but three patients responded both clinically and radiographically to decompressive surgery. Those patients who did not benefit from surgical intervention had normal PFRs. We conclude that: 1) PFRs are smaller in most patients with CM I; 2) a smaller PF may be a primary cause of tonsillar herniation; 3) patients with CM I who have smaller PFRs tend to develop symptoms earlier than those with normal values; 4) patients with smaller PFRs tend to respond better to suboccipital decompression.

The surgical treatment of Chiari I malformation

SummaryA retrospective study was undertaken on 133 patients with a Chiari I malformation treated within the last 16 years at the Departments of Neurosurgery at the Nordstadt Hospital Hannover, Germany, and the University of California, Los Angeles, U.S.A. Ninety-seven patients presented with symptoms related to accompanying syringomyelia and 4 with associated syringobulbia. They underwent 149 surgical procedures and were followed for a mean of 39±52 months. A decompression at the foramen magnum was performed in 124 patients, while 22 of those with syringomyelia were treated by shunting (7 syringosubarachnoid shunts, 15 syringoperitoneal or -pleural shunts), and 3 by ventriculoperitoneal shunts for hydrocephalus.Except for ventriculoperitoneal shunting, at least a short-term decrease in size of an associated syrinx was observed for all procedures in the majority of cases. However, no long-term benefit was observed for syrinx shunting operations. The best clinical longterm results were obtained with decompression of the foramen magnum in patients with (86% free of a clinical recurrence) and without syringomyelia (77% free of a clinical recurrence). We advise against syrinx shunting, a large craniectomy, and obex plugging which are associated with higher recurrence rates. Instead, surgery should consist of a small craniectomy, opening of the dura, archnoid dissection to establish normal cerebrospinal fluid (CSF) outflow from the 4th ventricle, and a fascia lata durai graft.

Analysis of cervical spine curvature in patients with cervical spondylosis.

&NA; Computer‐aided design techniques were used to analyze the degree of spinal curvature shown on cervical spine radiograms of 28 patients. On films standardized as to size, a geometrical chord was constructed from the 2nd to the 7th cervical vertebrae (C2 to C7), and an arc was drawn along the posterior margin of the vertebrae. The resulting area was used as an index of curvature, and the spinal canal diameter was measured. Severity of myelopathy as well as clinical improvement was related to the geometrical data. There was no clear correlation between severity of the preoperative myelopathy and degree of curvature. Severe myelopathy was seen in association with straight, lordotic, and hyperlordotic spines. Neck pain was most severe in patients with reversed cervical curvature. The degree of curvature, however, seems to relate to the postoperative clinical outcome. Patients with relatively normal curvature showed the greatest improvement in symptoms and signs. Postoperative magnetic resonance scanning confirms that posterior migration of the spinal cord after laminectomy may be inadequate to clear osteophytes in patients with straightened or reversed curvature of the cervical spine. Spinal geometry should be considered in the selection of the best surgical procedure and the extent of laminectomy for patients with spondylotic myelopathy. Significant abnormalities of spinal curvature may account for some instances of poor outcome after laminectomy.

Blunt trauma to the high cervical carotid artery

Closed injuries to the neck, occasionally associated with mandibular fractures, can result in trauma to the internal carotid artery at the high cervical level opposite the uppermost cervical vertebrae. Such arterial injuries range from spasm to intimal tear with thrombus formation, medial tear, and aneurysm formation. These types of lesions may overlap. Ten patients are presented, five with traumatic carotid occlusions and five with traumatic aneurysms. The clinical diagnosis of traumatic cervical carotid occlusion may be difficult because of the absence of physical trauma to the neck. The diagnosis of aneurysm poses fewer problems. Oculopneumoplethysmography, computerized tomographic head scanning, and carotid arteriography with cross compression are the most useful diagnostic techniques. Thrombectomy should be carried out early, particularly in the presence of fluctuating neurological signs. Aneurysms that cannot be approached directly may necessitate carotid ligation.

Phenotypic definition of chiari type I malformation coupled with high-density SNP genome screen shows significant evidence for linkage to regions on chromosomes 9 and 15

Chiari type I malformation (CMI; OMIM 118420) is narrowly defined when the tonsils of the cerebellum extend below the foramen magnum, leading to a variety of neurological symptoms. It is widely thought that a small posterior fossa (PF) volume, relative to the total cranial volume leads to a cramped cerebellum and herniation of the tonsils into the top of the spinal column. In a collection of magnetic resonance imagings (MRIs) from affected individuals and their family members, we measured correlations between ten cranial morphologies and estimated their heritability in these families. Correlations between bones delineating the PF and significant heritability of PF volume (0.955, P = 0.003) support the cramped PF theory and a genetic basis for this condition. In a collection of 23 families with 71 affected individuals, we performed a genome wide linkage screen of over 10,000 SNPs across the genome to identify regions of linkage to CMI. Two‐point LOD scores on chromosome 15 reached 3.3 and multipoint scores in this region identified a 13 cM region with LOD scores over 1 (15q21.1‐22.3). This region contains a biologically plausible gene for CMI, fibrillin‐1, which is a major gene in Marfan syndrome and has been linked to Shprintzen–Goldberg syndrome, of which CMI is a distinguishing characteristic. Multipoint LOD scores on chromosome 9 maximized at 3.05, identifying a 40 cM region with LOD scores over 1 (9q21.33‐33.1) and a tighter region with multipoint LOD scores over 2 that was only 8.5 cM. This linkage evidence supports a genetic role in Chiari malformation and justifies further exploration with fine mapping and investigation of candidate genes in these regions.

Principles and practice of spine surgery

Principles and practice of spine surgery , Principles and practice of spine surgery , کتابخانه مرکزی دانشگاه علوم پزشکی تهران

Sphenoid Sinus Mucocele (Anterior Clinoid Variant) Mimicking Diabetic Ophthalmoplegia and Retrobulbar Neuritis

Two patients (two men, 56 and 59 years old) had sphenoid sinus mucocele originating in the anterior clinoid process. In one case the mucocele initially mimicked diabetic ophthalmoplegia with pupil-sparing palsy of the oculomotor (third) nerve. After resolution of the palsy, severe visual loss developed with minimal recovery of vision after surgery. The second patient had recurrent episodes of retrobulbar optic neuropathy with optic atrophy and decreased vision. Visual loss from sphenoid sinus mucoceles is usually associated with a poor prognosis if surgical treatment is delayed more than seven to ten days.

Syringomyelia persistence after Chiari decompression as a result of pseudomeningocele formation: implications for syrinx pathogenesis: report of three cases.

OBJECTIVE AND IMPORTANCE We present the cases of three patients in whom pseudomeningocele (PSM) formations after posterior fossa decompression of hindbrain herniations (Chiari I malformations) were associated with persistence of syringomyelia. The physiological importance of correcting this complication has not been previously described. CLINICAL PRESENTATION We identified three patients who developed suboccipital PSMs after undergoing posterior fossa decompression for hindbrain herniations and syringomyelia. All three patients experienced persistence of their symptoms and their syringomyelia, despite adequate posterior fossa decompression. TECHNIQUE Subsequent exploration revealed cerebrospinal fluid leaking either from the dural suture line (one patient) or from perforations found within the bed of a polyglactin mesh dural graft (two patients). Correction of the PSM resulted in resolution of both the syringomyelia and the symptoms in all three patients. DISCUSSION The persistence of syringomyelia in the presence of a PSM may be the result of dissipation of the cerebrospinal fluid systolic pressure wave into the distensible PSM cavity. This phenomenon suggests that the cerebrospinal fluid pressure exerted on the spinal cord surface favors resolution of the syrinx cavity.

Acute foramen magnum syndrome caused by an acquired Chiari malformation after lumbar drainage of cerebrospinal fluid: report of three cases.

OBJECTIVE AND IMPORTANCEThe perioperative use of lumbar drainage of cerebrospinal fluid (CSF) is relatively common in neurosurgery, and the development of “acquired” Chiari malformations (tonsillar herniation) with lumbar CSF diversion procedures has been reported. CLINICAL PRESENTATION We describe the history of three patients who developed a foramen magnum syndrome, attributable to acquired Chiari I malformations, after perioperative lumbar drainage of CSF. CONCLUSION We propose that the mechanism responsible for Chiari I malformations involves a negative pressure gradient between the cranial and spinal regions, created by CSF drainage. Theories regarding the formation of acquired Chiari I malformations, the possible synergistic roles of intracranial pathological conditions and CSF drainage in the development of this entity, and the implications for the use of perioperative lumbar drainage are discussed.

Endoscopic Third Ventriculostomy for Treatment of Noncommunicating Syringomyelia Associated with a Chiari I Malformation and Hydrocephalus: Case Report and Pathophysiological Considerations

OBJECTIVE AND IMPORTANCE A Chiari I malformation associated with syringomyelia and hydrocephalus is a rare condition. We report the successful use of endoscopic third ventriculostomy for the treatment of this pathological entity. The successful use of this technique in such a case has not been previously described, and the results allow us to speculate on the pathophysiological mechanism involved. CLINICAL PRESENTATION A 34-year-old woman presented with headaches, a motor deficit of the right upper limb, and gait dyspraxia. Magnetic resonance imaging scans demonstrated dilation of all ventricles, compression of the retrocerebellar cerebrospinal fluid space, downward displacement of the tonsils, and syringomyelia. Syringomyelia involved the cervicodorsal cord below C3, with a syrinx-free segment between C1 and C3 and no enlargement of the rostral part of the central canal. INTERVENTION Endoscopic third ventriculostomy resulted in prompt improvement of the clinical symptoms. Postoperative magnetic resonance imaging scans demonstrated shrinkage of the syrinx and return of the cerebellar tonsils to their physiological positions. CONCLUSION This experience demonstrates that endoscopic third ventriculostomy, which is a simple, safe technique, may be the treatment of choice for associated Chiari I malformations, hydrocephalus, and syringomyelia (even the noncommunicating type).