ABSTRACT
Institute and personal experience (over 25 years) of basilar invagination was reviewed. The database of the department included 3300 patients with craniovertebral junction pathology from the year 1951 till date. Patients with basilar invagination were categorized into two groups based on the presence (Group A) or absence (Group B) of clinical and radiological evidence of instability of the craniovertebral junction. Standard radiological parameters described by Chamberlain were used to assess the instability of the craniovertebral junction. The pathogenesis and clinical features in patients with Group A basilar invagination appeared to be related to mechanical instability, whereas it appeared to be secondary to embryonic dysgenesis in patients with Group B basilar invagination. Treatment by facetal distraction and direct lateral mass fixation can result in restoration of craniovertebral and cervical alignment in patients with Group A basilar invagination. Such a treatment can circumvent the need for transoral or posterior fossa decompression surgery. Foramen magnum bone decompression appears to be a rational surgical treatment for patients having Group B basilar invagination. The division of patients with basilar invagination on the basis of presence or absence of instability provides insight into the pathogenesis of the anomaly and a basis for rational surgical treatment.
Subject(s)
Arnold-Chiari Malformation/therapy , Atlanto-Axial Joint/surgery , Decompression, Surgical/methods , Platybasia , Syringomyelia/therapy , Atlanto-Axial Joint/pathology , Foramen Magnum/pathology , Humans , Magnetic Resonance Imaging/methods , Platybasia/classification , Platybasia/diagnosis , Platybasia/therapy , Tomography, X-Ray Computed/methodsABSTRACT
OBJECT: The authors analyzed the cases of 190 patients with basilar invagination that was diagnosed on the basis of criteria laid down in 1939 by Chamberlain to assess the appropriate surgical procedure. METHODS: Depending on the association with Chiari malformation, the anomaly of basilar invagination was classified into two groups. Eighty-eight patients who had basilar invagination but no associated Chiari malformation were assigned to Group I; the remainder of the patients, who had both basilar invagination and Chiari malformation, were assigned to Group II. The principal pathological characteristic was observed to be direct brainstem compression due to odontoid process indentation in Group I and a reduction in posterior cranial fossa volume in Group II. CONCLUSIONS: Despite the anterior concavity of the brainstem in both groups, transoral surgery was the most suitable procedure for those patients in Group I and decompression of the foramen magnum was found to be appropriate for patients in Group II. After surgical decompression, a fixation procedure was found to be necessary in most Group I cases, but only in a small minority of Group II cases.
Subject(s)
Platybasia/surgery , Adolescent , Adult , Age Factors , Arnold-Chiari Malformation/complications , Arnold-Chiari Malformation/pathology , Arnold-Chiari Malformation/surgery , Atlanto-Axial Joint/surgery , Bone Plates , Bone Screws , Bone Transplantation , Brain Diseases/etiology , Brain Stem/pathology , Child , Cranial Fossa, Posterior/pathology , Female , Follow-Up Studies , Foramen Magnum/surgery , Humans , Joint Dislocations/surgery , Joint Instability/surgery , Male , Middle Aged , Odontoid Process/pathology , Platybasia/classification , Platybasia/complications , Platybasia/pathology , Sex FactorsABSTRACT
The clinical, radiological and surgical findings of 56 patients with congenital malformations of the craniovertebral junction who underwent surgical intervention in the Department of Neurosurgery, Hacettepe University Medical School were reviewed. The anomalies were classified according to their embryonic origin. Forty-two cases of the series were major abnormalities formed by the combination of more than one germ layer.
