1/32. Respiratory sinus arrhythmia of brainstem lesions.In this pilot study we investigated the hypothesis that intrinsic and extrinsic brainstem lesions situated within the pontomedullary region would effect the integrity of respiratory sinus arrhythmia. The study sample consisted of three patients with anatomic brainstem abnormalities associated with isolated Chiari I malformation, Chiari II malformation with syringobulbia, and achondroplasia with cervicomedullary compression. They were compared to an age- and sex-matched control group of nine patients. Each subject's electrocardiogram was recorded in a quiet room and digitized by a personal computer during five 1-minute periods. R-R intervals within each 1-minute period were converted to heart rate in 120 successive 0.5-second intervals. The resultant heartrate time series was converted to its underlying frequency composition by a fast Fourier transform and averaged across minutes. Respiratory sinus arrhythmia was defined as the variability in the time series over a frequency range (0.096 to 0.48 Hz) corresponding to a range of respiratory rates from 6 to 30 breaths per minute. Analysis revealed a significant reduction in respiratory sinus arrhythmia (P < .05), defined as the summated area under the curve, with a mean for controls of 35.42 /-28.13 SD and for subjects of 17.20 /-11.50 SD. There was a gradient of abnormality noted, with the mildest deviation in respiratory sinus arrhythmia for the patient with isolated Chiari I malformation and maximum deviation seen in the patient with extrinsic cervicomedullary compression.- - - - - - - - - - ranking = 1keywords = compression (Clic here for more details about this article) |
2/32. achondroplasia and cervicomedullary compression: prospective evaluation and surgical treatment.The association between sudden death and cervicomedullary compression in infants with achondroplasia has been well described. Prospective clinical and imaging evaluations have been recommended to identify those infants with achondroplasia who are at risk of dying suddenly from respiratory arrest secondary to unrecognized cervicomedullary compression. Since 1988, we have prospectively evaluated 11 infants (average age 13 weeks) with achondroplasia who were asymptomatic for cervicomedullary compression on initial clinical evaluation. Craniocervical magnetic resonance imaging (MRI) findings included narrowing of the foramen magnum, effacement of the subarachnoid spaces at the cervicomedullary junction, abnormal intrinsic cord signal intensity and mild to moderate ventriculomegaly. Two patients with severe cord compression underwent immediate decompression. Two patients developed opisthotonic posturing within 3 months of evaluation and underwent foramen magnum decompression, including suboccipital craniectomy and atlantal laminectomy. Surgery in all cases revealed forward extension of the squamous portion of the occipital bone, thickened posterior rim of the foramen magnum and a dense fibrotic epidural band. There were no complications from surgery. Seven patients did not require surgery and were followed closely. All 11 patients remain asymptomatic at follow-up (mean 4.6 years; range 16 months to 7.3 years), and no patient has required a diversionary shunt procedure. The results of this prospective study confirm that early clinical and MRI evaluations are necessary to determine whether infants with achondroplasia have cervicomedullary compression. With early recognition, an immediate decompression can be performed safely to avoid serious complications associated with cervicomedullary compression, including sudden death. copyright copyright 1999 S. Karger AG, Basel- - - - - - - - - - ranking = 6.5keywords = compression (Clic here for more details about this article) |
3/32. Perioperative intracranial hemorrhage in achondroplasia: a case report.We report a case of a 35-year-old man with achondroplasia who previously had thoracolumbar decompressive laminectomies, who developed recurrence of spinal stenosis at the thoracolumbar junction. The patient underwent standard repeat thoracolumbar decompression, removal of a disc, and spinal fusion with instrumentation in the prone position. Postoperatively the patient was confused. Computed tomography (CT) revealed hemorrhages in both cerebellar hemispheres with surrounding edema and mild mass effect. These were interpreted as venous hemorrhages. Conservative therapy was successful. This is the first case report of perioperative venous intracranial hemorrhage in the context of spinal surgery for achondroplasia. Distinctive anatomic characteristics of achondroplasia, combined with several potentially modifiable aspects of his management, may have predisposed the patient to this complication.- - - - - - - - - - ranking = 0.5keywords = compression (Clic here for more details about this article) |
4/32. Deformation across the zone of callotasis during loading. radiostereometric analysis in a patient with achondroplasia.The present study demonstrates that high-resolution radiostereometric analysis (RSA) can be used to assess global longitudinal compressive deformation across the callotasis zone during loading. In an achondroplastic patient operated with bifocal lengthening of the tibia by use of the Ilizarov external fixator, the axial compressive intersegmental strain in the proximal lengthening zone under a load of 71% of body weight was 7.7 mm. The proximal lengthening zone was 51.0 mm, and accordingly the overall linear strain across the callotasis was 15.1%. This large strain value found in distraction osteogenesis 6 weeks after end of distraction is not consistent with classical theory of the magnitude of micromotion needed for adequate stimulation of bone formation in fracture healing. The increased axial displacement did not stimulate bone healing and delayed union was observed. This one single observation does not allow for any conclusions to be drawn about the relationship of strain to fracture healing, but further and refined use of the RSA method will certainly improve our understanding of the role of axial strains in distraction osteogenesis.- - - - - - - - - - ranking = 0.012446085987146keywords = fracture (Clic here for more details about this article) |
5/32. trigeminal neuralgia associated with achondroplasia. Case report with literature review.A 59-year-old male with a history of 2 years of typical trigeminal neuralgia manifested the characteristics of achondroplasia. X-ray and magnetic resonance imaging demonstrated basilar impression, deformity of the posterior fossa with marked asymmetry of petrous bone and compression of pons and trigeminal nerve by the left vertebral artery and anterior inferior cerebellar artery. Microvascular decompression was performed through a suboccipital craniectomy. The neuralgia disappeared soon after surgery and remains completely resolved until today. This is the first reported case of trigeminal neuralgia in a patient with achondroplasia. The deformity of the skull base was considered to influence the development of the trigeminal neuralgia.- - - - - - - - - - ranking = 1keywords = compression (Clic here for more details about this article) |
6/32. airway management of an achondroplastic dwarf with hydrocephalus undergoing decompression surgery.The neurological problem of achondroplasia is hydrocephalus which may arise from stenosis of the foramen magnum secondary to occipital hypertrophy. The spine is also affected by abnormalities in the cervical region (odontoid hypoplasia and occipitalization of C1), which can compound the problem of cord compression. We report a rare instance of achondroplasia in a 3-month-old female infant with the risk of spinal cord compression during the manipulation of endotracheal intubation. For fear of that the surgeon inclined awake intubation in order that spinal cord intactness could be confirmed by neurological test on the spot after intubation. Awake oral endotracheal intubation was performed although with some difficulty, yet the motor function at the first cervical spinal level was unmolested as revealed by neurological test after intubation.- - - - - - - - - - ranking = 3keywords = compression (Clic here for more details about this article) |
7/32. Arachnoid cyst resulting in tonsillar herniation and syringomyelia in a patient with achondroplasia. Case report.achondroplasia has been associated with varying degrees of cervicomedullary and spinal compression, although usually in the pediatric population. Large arachnoid cysts have also been found to result in tonsillar herniation and syringomyelia. The authors present the case of a patient with achondroplasia who presented with symptoms of foramen magnum compression and syringomyelia, and who was subsequently found to have a large posterior fossa arachnoid cyst. This 38-year-old woman with achondroplasia presented with an 8-month history of headache and numbness of the hands and fingers. Admission magnetic resonance (MR) imaging of the head and spine revealed a large arachnoid cyst in the posterior cranial fossa, a 6-mm tonsillar herniation consistent with an acquired Chiari malformation, and a large cervicothoracic syrinx. The patient was treated using suboccipital craniectomy, C-1 laminectomy, fenestration of the arachnoid cyst, and decompression of the acquired Chiari malformation with duraplasty. Surgical decompression resulted in improvement of the presenting symptoms, adequate decompression of crowding at the foramen magnum, and resolution of the syrinx. Although there was only partial reduction in the retrocerebellar cisternal space on follow-up MR imaging, no residual symptoms were related to this.- - - - - - - - - - ranking = 2.5keywords = compression (Clic here for more details about this article) |
8/32. Irreversible respiratory failure in an achondroplastic child: the importance of an early cervicomedullary decompression, and a review of the literature.The authors report the case of a girl with achondroplasia suffering from a progressively worsening hypotonic quadriparesis. CT scan showed slight dilatation of ventricular and subarachnoid spaces, with well-defined evidence of cortical sulci and gyri. This aspect was compatible with the diagnosis of macrocrania and megalencephaly (CP being 51 cm). The foramen magnum was narrowed, the transverse diameter measuring 15 mm and the 50th percentile being, for age, 26 mm. Somatosensory evoked potentials (SEPs) revealed bilaterally prolonged interpeak latencies Erb-N13, slowing of central conduction time N13-N20 from right median nerve stimulation, and block from left median nerve. The suspicion of cervicomedullary compression was confirmed by MRI, showing a very marked stenosis with compression exerted by the odontoid process. Further, a stenotic cervical canal and optic nerves verticalization were manifest. The patient underwent neurosurgical decompression by suboccipital craniectomy and cervical-C1 laminectomy. In spite of treatment, both neurologic and respiratory problems (rapid, shallow and almost abdominal breathing) were unchanged. The girl died 4 1/2 months later. The authors emphasize the important role of SEPs in detection of cervicomedullary compression in achondroplastic children and also stress the necessity of an early surgical treatment as the only condition for possible clinical improvement and/or full recovery.- - - - - - - - - - ranking = 4keywords = compression (Clic here for more details about this article) |
9/32. Basilar impression in a child with hypochondroplasia.A 4-year-old boy with hypochondroplasia presented with delay in gross motor development. magnetic resonance imaging demonstrated basilar impression with compression at the craniovertebral junction and mild degree of hydrocephalus. Posterior fossa decompression resulted in improvement in neurologic function and relief of hydrocephalus.- - - - - - - - - - ranking = 1keywords = compression (Clic here for more details about this article) |
10/32. Apneustic breathing. A characteristic feature of brainstem compression in achondroplasia?We have observed apneustic breathing in five patients with achondroplasia. In contrast to experimental models of apneusis, these patients appeared to have intact vagal function and no evidence of pontine disease. However, all our patients displayed clinical, structural, and electrophysiologic features of cervicomedullary compression, a well-recognized complication of achondroplasia. The degree of apneustic breathing was reduced in the majority of our patients following decompressive surgery. Traditional theories on the pathogenesis of apneustic breathing cannot satisfactorily explain the presence of apneustic breathing in our patients. We suggest that cervicomedullary compression may be capable of producing apneustic breathing in the absence of vagal or pneumotaxic center lesions.- - - - - - - - - - ranking = 3keywords = compression (Clic here for more details about this article) |
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