Inheritance of Chiari-Like Malformation: Can a Mixed Breeding Reduce the Risk of Syringomyelia?

Canine Chiari-like malformation (CM) is a complex abnormality of the skull and craniocervical junction associated with miniaturization and brachycephaly which can result in the spinal cord disease syringomyelia (SM). This study investigated the inheritance of CM in a Griffon Bruxellois (GB) family and feasibility of crossbreeding a brachycephalic CM affected GB with a mesaticephalic normal Australian terrier and then backcrossing to produce individuals free of the malformation and regain GB breed characteristics. The study family cohort (n = 27) included five founder dogs from a previous baseline study of 155 GB which defined CM as a global malformation of the cranium and craniocervical junction with a shortened skull base and increased proximity of the cervical vertebrae to the skull. T1-weighted sagittal DICOM images of the brain and craniocervical junction were analysed for five significant traits (two angles, three lines) identified from the previous study and subsequent Qualitative Trait Loci analysis. Mean measurements for mixed breed, pure-breed and baseline study groups were compared. Results indicated that mixed breed traits posed less risk for CM and SM and were useful to distinguish the phenotype. Moreover on the MR images, the filial relationships displayed by the traits exhibited segregation and those presenting the greatest risk for CM appeared additive towards the severity of the condition. The external phenotypes revealed that by outcrossing breed types and with careful selection of appropriate conformation characteristics in the first generation, it is possible to regain the GB breed standard and reduce the degree of CM. The four GB affected with SM in the study all exhibited reduced caudal skull development compared to their relatives. The craniocervical traits may be useful for quantifying CM and assessing the possibility of SM thus assisting breeders with mate selection. However, such a system requires validation to ensure appropriateness for all breeds at risk.

Effectiveness of breeding guidelines for reducing the prevalence of syringomyelia.

Several toy breed dogs are predisposed to syringomyelia (SM), a spinal cord disorder, characterised by fluid-filled cavitation. SM is a complex trait with a moderately high heritability. Selective breeding against SM is confounded by its complex inheritance, its late onset nature and high prevalence in some breeds. This study investigated the early outcome of existing SM breeding guidelines. Six hundred and forty-three dogs, 550 Cavalier King Charles spaniels (CKCS) and 93 Griffon Bruxellois (GB), were identified as having either one (454 dogs) or both parents (189 dogs) with MRI-determined SM status. Offspring without SM were more common when the parents were both clear of SM (SM-free; CKCS 70 per cent, GB 73 per cent). Conversely, offspring with SM were more likely when both parents had SM (SM-affected; CKCS 92 per cent, GB 100 per cent). A mating of one SM-free parent with an SM-affected parent was risky for SM affectedness with 77 per cent of CKCS and 46 per cent of GB offspring being SM-affected. It is recommended that all breeding dogs from breeds susceptible to SM be MRI screened; that the SM status at five years old is established; and all results submitted to a central database that can be used by dog breeders to better enable mate selection based on estimated breeding values.

Heritability of syringomyelia in Cavalier King Charles spaniels.

Mixed model analysis of 384 Cavalier King Charles spaniels (CKCS), with a magnetic resonance imaging diagnosis for the presence or absence of a syrinx, in conjunction with the Kennel Club pedigree records of all dogs registered from the mid 1980s to September 2007, revealed a moderately high estimate of heritability of syringomyelia (h(2)=0.37+/-0.15 standard error) when analysed as a binary trait. Inspection of cases where the disease segregated within families pointed to genes at more than one locus influencing syringomyelia. The availability of estimated breeding values for Kennel Club registered CKCS is a significant step in being able to select against syringomyelia, particularly given the difficulty of ascertaining the disease phenotype.

Comparison of posterior fossa decompression with and without duraplasty for the surgical treatment of Chiari malformation Type I in pediatric patients: a meta-analysis.

OBJECT: Surgery for Chiari malformation Type I (CM-I) is one of the most common neurosurgical procedures performed in children, although there is clearly no consensus among practitioners about which surgical method is preferred. The objective of this meta-analysis was to compare the outcome of posterior fossa decompression with duraplasty (PFDD) and posterior fossa decompression without duraplasty (PFD) for the treatment of CM-I in children. METHODS: The authors searched Medline-Ovid, The Cochrane Library, and the conference proceedings of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons (2000-2007) for studies meeting the following inclusion criteria: 1) surgical treatment of CM-I; 2) surgical techniques of PFD and PFDD being reported in a single cohort; and 3) patient age < 18 years. RESULTS: Five retrospective and 2 prospective cohort studies involving a total of 582 patients met the criteria for inclusion in the meta-analysis. Of the 582 patients, 316 were treated with PFDD and 266 were treated with PFD alone. Patient age ranged from 6 months to 18 years. Patients undergoing PFDD had a significantly lower reoperation rate (2.1 vs 12.6%, risk ratio [RR] 0.23, 95% confidence interval [CI] 0.08-0.69) and a higher rate of cerebrospinal fluid-related complications (18.5 vs 1.8%, RR 7.64, 95% CI 2.53-23.09) than those undergoing PFD. No significant differences in either clinical improvement (78.6 vs 64.6%, RR 1.23, 95% CI 0.95-1.59) or syringomyelia decrease (87.0 vs 56.3%, RR 1.43, 95% CI 0.91-2.25) were noted between PFDD and PFD. CONCLUSIONS: Posterior fossa decompression with duraplasty is associated with a lower risk of reoperation than PFD but a greater risk for cerebrospinal fluid-related complications. There was no significant difference between the 2 operative techniques with respect to clinical improvement or decrease in syringomyelia.

[The presyrinx state due to adhesive arachnoiditis: a case report].

We report a 66-year-old woman with a presyrinx state due to adhesive arachnoiditis. She had a history of subarachnoid hemorrhage one year ago. She became aware of gait disturbance and abnormal sensation at the chest 6 months ago. Neurological examination revealed weakness of the both lower extremities and sensory disturbance below the T6 level. MR images of the thoracic spine revealed swelling of the thoracic cord at the T3-4 level, with an intramedullary hyperintensity on T2 weighted images (WI) and hypointensity on T1-WI. The intramedullary hypointensity on T1-WI was less than the CSF intensity. In addition, the thoracic cord lower than T5 level was compressed by an arachnoid cyst in the spinal canal. The preoperative diagnosis was the presyrinx state due to adhesive arachnoiditis. An operation for detachment of arachnoidal adhesion and restoration of CSF flow pathway was performed. After one month from the operation, neurological findings were improved. Postoperative MR images revealed improvement of swelling of the thoracic cord and intramedullary abnormal intensity. The arachnoid cyst in the spinal canal was decreased in the size. The presyrinx state is recently recognized condition before the formation of syringomyelia and that is known to resolve with proper treatment. We wish to emphasize we could prevent a progression to syringomyelia by a proper treatment for the presyrinx state.

The nature, meanings, and dynamics of lived experiences of a person with syringomyelia: a phenomenological study.

Syringomyelia, considered a rare neurological disease, is relatively uninvestigated in the nursing literature. The aims of this qualitative phenomenological case study were to discover the nature, meanings, and dynamics of lived experiences of a 52-year-old Caucasian male with syringomyelia. Using van Manen's Method of Phenomenological inquiry (van Manen, 1990), data were collected, checked, and analyzed according to the philosophy, approach, and methodological procedures of phenomenology. Findings revealed an overarching theme of engulfment by disease. Essential themes included loss of abilities, struggles to adapt to changes, and life as a person who was disabled. Eleven sub-themes were also identified. Implications for nursing practice are discussed.

The role of acute decompression and restoration of spinal alignment in the prevention of post-traumatic syringomyelia: case report and review of recent literature.

STUDY DESIGN: Case report. INTRODUCTION: Acute post-traumatic syringomyelia formation after spinal cord injury has been considered a rare complication. At this writing, most recent reports have surfaced in neurosurgical journals. As an entity, post-traumatic syringomyelia has not been widely appreciated. It has been confused with conditions such as Hansen's disease or ulnar nerve compression at the cubital tunnel. One study also demonstrated that the occurrence of syrinx is significantly correlated with spinal stenosis after treatment, and that an inadequate reduction of the spine may lead to the formation of syrinx. This reported case describes a patient in whom post-traumatic syringomyelia began to develop 3 weeks after injury, which improved neurologically after adequate decompression. SUMMARY OF BACKGROUND DATA: A 30-year-old man sustained a 20-foot fall at work. He presented with a complete spinal cord injury below T4 secondary to a T4 fracture dislocation. The patient underwent open reduction and internal fixation of T1-T8. After 3 weeks, the patient was noted to have ascending weakness in his bilateral upper extremities and some clawing of both hands. METHODS: A computed tomography myelogram demonstrated inability of contrast to pass through the T4-T5 region from a lumbar puncture. An incomplete reduction was noted. The canal showed significant stenosis. A magnetic resonance image of the patient's C-spine showed increased signal in the substance of the cord extending into the C1-C2 area. The patient returned to the operating room for T3-T5 decompressive laminectomy and posterolateral decompression including the pedicles, disc, and posterior aspect of the body. Intraoperative ultrasound monitoring showed a good flow of cerebrospinal fluid past the injured segment. RESULTS: On postoperative day 1, the clawing posture of the patient's hands was significantly diminished, and the patient noted an immediate improvement in his hand and arm strength. Over the next few days, the patient's strength in the bilateral upper extremities increased to motor Grade 4/5 on manual testing. A magnetic resonance image 4 weeks after decompression showed significant improvement in the cord diameter and signal. CONCLUSIONS: Post-traumatic syringomyelia has not been reported at so early a stage after injury. This disorder is an important clinical entity that must be recognized to prevent potentially fatal or devastating complications. As evidenced by the reported patient and the literature, if this disorder is discovered and treated early, permanent deficit can be avoided. The prevention of post-traumatic syringomyelia requires anatomic realignment and stabilization of the spine without stenosis, even in the case of complete injuries, to maintain the proper dynamics of cerebrospinal fluid flow.

Developmental anomalies affecting the fourth ventricular outflow region: a report of four cases.

Developmental anomalies affecting the hind brain, cerebellum and spinal cord with associated malformations of the skull base and cervical spine, show a wide degree of variability and overlap so that cases are often difficult to classify into a fixed category such as the Arnold-Chiari malformation Type 1 or Type 2, or the Dandy-Walker syndrome. The 4 cases presented here illustrate this problem and offer support for the hypothesis that these conditions may be merely the varying expression of a common pathological process. The CT brain scan may prove to be a valuable means of allowing early recognition of these anomalies so that effective surgical treatment can be given at an early stage in their natural history, possibly thereby preventing the progression or development of central cord cavitation with its significant and permanent disabilities.