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This case report describes the clinical journey of a male patient in early childhood with developmental delay, failure to thrive, worsening right-sided head tilt torticollis and regression of motor skills with spasticity of the lower limbs. The case was complex due to the early onset and gradually worsening symptoms, including a decline in established motor milestones. Genetic testing to investigate the delayed neurodevelopment revealed a FRA10AC1 variant that did not fully explain the patient's phenotype. Investigations were delayed due to the coronavirus disease 2019 pandemic and other factors related to the patient. Eventually, MRI revealed basilar invagination with cord compression and cord oedema at the C1-C2 junction. Treatment included foramen magnum decompression and management of symptoms using a multidisciplinary approach. Treatment resulted in a remarkable recovery. The patient regained some motor abilities and reached the 50th weight percentile., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Secondary basilar invagination or basilar impression is an anomaly at the craniovertebral junction where the odontoid process prolapses into the foramen magnum with the risk of compressing adjacent structures and obstructing the proper flow of cerebrospinal fluid (CSF). The incidence is less than 1% in the general population and occurs mainly in the first three decades of life when it is associated with malformations of the neuroaxis. In older age, the main aetiologies are diseases that alter bone mineral density. The clinical course is usually progressive and the most common symptoms are asthenia, cervical pain and restricted movement, but also dysphonia, dyspnoea and dysphagia. It is a progressive disease which, if left untreated, can cause severe neurological damage and death. We report the case of a 79-year-old woman with osteoporosis and progressive dysphagia leading to severe malnutrition, which conditioned the decision not to intervene due to the high perioperative risk., (Copyright © 2024 SEEN and SED. Published by Elsevier España, S.L.U. All rights reserved.)

Objective: Craniocervical junction (CCJ) pathologies with ventral neural element compression are poorly understood, and appropriate management requires accurate understanding, description, and a more uniform nomenclature. The aim of this study was to evaluate patients to identify anatomical clusters and better classify CCJ disorders with ventral compression and guide treatment., Methods: A retrospective review of adult and pediatric patients with ventral CCJ compression from 2008 to 2022 at a single center was performed. The incidence of anatomical abnormalities and compressive etiologies was assessed. Surgical approach, radiographic data, and outcomes were recorded. Association rules analysis (ARA) was used to assess variable clustering., Results: Among 51 patients, the main causes of compression were either purely bony (retroflexed dens [n = 18]; basilar invagination [BI; n = 13]) or soft tissue (degenerative pannus [n = 16]; inflammatory pannus [n = 2]). The primary cluster in ARA was a retroflexed dens, platybasia, and Chiari malformation (CM), and the secondary cluster was BI, C1-2 subluxation, and reducibility. These, along with degenerative pannus, formed the three major classes. In assessing the optimal treatment strategy, reducibility was evaluated. Of the BI cases, 12 of the 13 patients had anterolisthesis of C1 that was potentially reducible, compared with 2 of the 18 patients with a retroflexed dens (both with concomitant BI), and no pannus cases. The mean C1-2 facet angle was significantly higher in BI at 32.4°, compared with -2.3° in retroflexed dens and 8.1° in degenerative pannus (p < 0.05). Endonasal decompression with posterior fixation was performed in 48 (94.0%) of the 51 patients, whereas posterior reduction/fixation alone was performed in 3 patients (6.0%). Of 16 reducible cases, open posterior reduction alone was successful in 3 (60.0%) of 5 cases, with all successes containing isolated BI. Reduction was not attempted if vertebral anatomy was unfavorable (n = 9) or the C1 lateral mass was absent (n = 5). The mean follow-up was 28 months. Symptoms improved in 88.9% of patients and were stable in the remaining 11.1%. Tracheostomy and percutaneous G-tube placement occurred in 7.8% and 11.8% of patients, respectively. Reoperation for an endonasal CSF leak repair or posterior cervical wound revision both occurred in 3.9% of patients., Conclusions: In classifying, one cluster caused decreased posterior fossa volume due to an anatomical triad of retroflexed dens, platybasia, and CM. The second cluster caused pannus formation due to degenerative hypertrophy. For both, endonasal decompression with posterior fixation was ideal. The third group contained C1 anterolisthesis characterized by a steep C1-2 facet angle causing reducible BI. Posterior reduction/fixation is the first-line treatment when anatomically feasible or endonasal decompression with in situ posterior fixation when anatomical constraints exist.

Introduction: There are many craniometric measurements that are used in evaluating craniovertebral junction (CVJ) pathologies such as basilar invagination, atlantoaxial dislocation and platybasia. Therefore, it is important to determine the normal reference range of the craniometric measurements. This study aims to determine the morphometric reference values of the bony structures in the CVJ from cone-beam computed tomography (CBCT) images of a group of South Eastern Anatolian population., Materials and Methods: The CBCT images of 300 individuals were retrospectively evaluated. 14 parameters on midsagittal and 2 parameters on the coronal plane were studied. The data were statistically evaluated., Results: Measurement results were found as follows; the distances between odontoid process (OP) and McGregor line as 0.31 ± 3.22 mm, OP and Chamberlain line 1.06 ± 3.22 mm, OP and McRae line 5.30 ± 1.59 mm, OP and Fischgold digastric line 8.70 ± 4.12 mm, OP and Fischgold bimastoid line - 5.15 ± 4.86 mm, length of McRae line 35.58 ± 2.52 mm, atlantodental interval 1.28 ± 0.48 mm, posterior atlantodental interval 19.54 ± 2.24 mm, basion axial interval 4.01 ± 1.83 mm, basion dental interval 4.92 ± 1.77 mm, length of Modified Ranawat line 28.66 ± 2.38 mm, length of Redlund-Johnell line 35.11 ± 4.09 mm, clivus canal angle 157.62° ± 11.85°, Welcher basal angle 130.83° ± 6.29°, craniocervical tilt 126.98° ± 12.24° and Powers ratio as 0.72 ± 0.06., Conclusion: In this study, the morphometric values were evaluated according to age and gender in individuals who did not have any radiologic anomalies. The normal reference ranges may be useful for researchers who are researching pathology in this region. It is recommended to conduct further studies with different populations to determine the normal reference range.

Objectives: To investigate the diagnostic value of clivopalate angle (CPA) for basilar invagination (BI) at magnetic resonance imaging (MRI)., Methods: In this retrospective case-control study, CPA, clivodens angle (CDA), and clivoaxial angle (CXA) were measured on midsagittal MR images from 112 patients with BI (22 men; mean age, 43.9 years ± 13.1 years; range, 21-79 years) and 200 control subjects (57 men; mean age, 47.1 years ± 13.3 years; range, 20-80 years). Intraclass correlation coefficient (ICC), linear regression, Mann-Whitney U test, binary logistic regression, and receiver operating characteristic (ROC) curve were used for statistical analysis., Results: Clivopalate angle showed better inter-observer agreement (ICC = 0.951) than CXA (0.867) or CDA (0.853). CPA significantly correlated with CXA (R = 0.811, p < 0.001) and CDA (R = 0.716, p < 0.001). Patients with BI had a significantly smaller CPA (45.9° ± 9.9°) than control subjects (61.9° ± 6.2°) (p < 0.001). With the optimal cutoff value of 53.5°, CPA had a sensitivity of 0.839 (94/112) and a specificity of 0.915 (183/200). The area under the ROC curve (AUC) was 0.937 (95% CI, 0.911-0.963) for CPA, which was similar to that of CXA (AUC, 0.957; 95% CI, 0.936-0.978) or CDA (AUC, 0.925; 95% CI, 0.892-0.957). The combination of CPA and CDA or CXA showed a higher diagnostic value than CDA or CXA alone., Conclusions: The diagnostic performance of CPA was similar to that of CXA or CDA, but CPA might be more reliable in evaluation of BI. CPA provided complementary information to CXA and CDA., Key Points: • Clivopalate angle has a high diagnostic value for basilar invagination. • Clivopalate angle demonstrates high inter-reader agreement than does clivoaxial angle or clivodens angle. • Clivopalate angle provides complementary information to clivoaxial angle and clivodens angle.

Background: The mechanisms of pendular seesaw nystagmus (SSN) remain unknown., Methods: We evaluated modulation of pendular SSN by removal of visual fixation, convergence, and positional changes in 2 patients, one with bitemporal hemianopia due to a traumatic damage of the optic chiasm and the other with platybasia compressing the medulla and lower cerebellum., Results: In both patients, the pendular SSN markedly decreased or disappeared with convergence, without visual fixation in darkness, during static head tilt toward each shoulder while sitting and while supine., Conclusions: The similar patterns of nystagmus modulation observed in our patients with a different etiology indicate a common role of both visual and otolithic inputs in generating pendular SSN.

Background: The cervical spine is one of the main sites of manifestation in rheumatoid arthritis outside of the extremities. It can have a decisive influence on disease course via the occurrence of mechanical instabilities as well as neurologic symptoms. Both adequate diagnosis and the corresponding surgical treatment represent a challenge for the involved physicians., Materials and Methods: This review presents relevant diagnostic strategies and possibilities for surgical intervention which aim to avoid potentially fatal neurologic symptoms. Basic literature and expert opinions are also discussed., Results and Conclusion: Through target-oriented surgical management, as well as tight clinical and radiologic monitoring during conservative and surgical therapy, potentially fatal disease courses can be avoided.

A teenage girl presented with progressively worsening neck and occipital pain since 8 months ago that was associated with restriction of neck movements, low to moderate grade fever, anorexia and weight loss followed by gradually progressive quadriparesis since 3 months ago. Neurological examination revealed spastic quadriparesis without cranial nerve palsy. MRI of the cervical spine revealed prevertebral and paravertebral abscess from clivus to C2/C3 level, which extended into the anterior epidural space at C1-C3 level, causing atlantoaxial dislocation. There was evidence of basilar invagination. The dislocated dens caused compression over the cervicomedullary junction. On this basis, a diagnosis of craniovertebral junction Pott's disease was made. The patient was given neck immobilisation with cervical collar, and antitubercular treatment was started. She showed significant improvement in her neurological deficit during follow-up.

A case is presented of a 35-year-old woman diagnosed with platybasia associated with Klippel-Feil syndrome type I. She was admitted to University Department of Neurology for clinical examination because of walking difficulties, dizziness, and intermittent vision disturbances. Neurological examination revealed a predominance of cerebellar symptomatology. Relevant diagnostic work-up included craniogram, cervical spine x-ray, computed tomography (CT) of the brain and craniocervical junction, magnetic resonance imaging of the brain, electroencephalography, ophthalmologic examination, urinary tract ultrasonography, laboratory tests, and psychological testing. CT of the craniocervical junction showed platybasia, congenital fusion of the second and third cervical vertebrae, and basilar invagination of dens axis. Platybasia is leveling of the angle between the floor of the anterior cranial fossa and posterior cranial fossa in the area of sella turcica, which is normally at 115-140 degrees. Basilar impression or invagination is moving up of the basis of the occiput and occipital condyles into the cranium, which means that the borders of the foramen magnum, condyles and adjacent bone are invaginated into the posterior fossa. Klippel-Feil syndrome type II is massive fusion of two of seven cervical vertebrae associated with short neck and low hair line.

The management of intradiploic CSF collection is controversial. Although it is a benign lesion, even then delay in diagnosis and treatment may lead to significant morbidity. The authors report a very rare case of giant posttraumatic intradiploic pseudomeningocele involving the occipital bone, occipital condyles, and clivus. The pathogenesis and management of intradiploic CSF collection are discussed. This 16-year-old boy presented with a history of enlarging swelling in the suboccipital region associated with headache, lower cranial nerve palsy, and features of high cervical compressive myelopathy. Investigations revealed a giant intradiploic lesion involving the occipital bone, condyles, and clivus associated with secondary basilar invagination, hydrocephalus, and syringomyelia. Intrathecal contrast administration did not reveal communication of intradiploic space with the subarachnoid space. A large occipital craniotomy was performed. A linear fracture and dural defect in the midline was identified, which was closed with fascial graft after removing the inner table of the skull. Cranioplasty was performed using the expanded calvarial bone. Ventriculoperitoneal shunt insertion was performed for hydrocephalus, and the patient improved remarkably. Posttraumatic intradiploic CSF collection, although a benign condition, may present with severe complications if treatment is delayed. Early diagnosis and treatment is essential. The authors suggest that this condition should be treated early, as for growing skull fractures.

We present the case of a 15-year-old boy with symptoms due to Klippel-Feil syndrome. Radiographs and CT scans demonstrated basilar impression, occipitalisation of C1 and fusion of C2/C3. MRI showed ventral compression of the medullocervical junction. Skull traction was undertaken pre-operatively to determine whether the basilar impression could be safely reduced. During traction, the C3/C4 junction migrated 12 mm caudally and spasticity resolved. Peri-operative skull-femoral traction enabled posterior occipitocervical fixation without decompression. Following surgery, cervical alignment was restored and spasticity remained absent. One year after surgery he was not limited in his activities. The surgical strategy for patients with basilar impression and congenital anomalies remains controversial. The anterior approach with decompression is often recommended for patients with ventral compression of the medullocervical region, but such procedures are technically demanding and carry a significant risk of complications. Our surgical strategy was an alternative solution. Prior to a posterior cervical fixation, without decompression, skull traction was used to confirm that the deformity was reducible and effective in resolving associated myelopathy.

Objective: To report our experience with cephalometry in evaluating velopharyngeal dysfunction (VPD) in velocardiofacial syndrome (VCFS) and its utility in assessing the role of cervical spine abnormalities in VPD, prior to surgical correction of VPD., Design: Clinical charts and cephalometric radiographs done prior to surgery for VPD were retrospectively analyzed to ascertain velopharyngeal measurements and cervical spine abnormalities., Patients: Twenty-six patients (age: 6-23 years) with molecularly confirmed VCFS., Setting: Wake Forest University Health Sciences (1997-2005)., Measurements: Cranial base angle, nasopharyngeal depth, velum length, and Need ratio at rest, velar dimple location, and velopharyngeal length during phonation; information on presence/absence of submucous cleft palate and cervical spine abnormalities were also obtained. The relationship between C1 anterior arch abnormalities and Need ratio was examined., Results: Seventy-three percent of the VCFS patients had excessive nasopharyngeal depth, 80% had an abnormal Need ratio, 50% had a short velum, 81% had a submucous or occult submucous cleft palate, 90.5% had a cervical spine abnormality (C1 anterior arch abnormalities in 38%) and 11.5% had platybasia. There was a significant difference in the Need ratio between patients with and without C1 anterior arch abnormalities., Conclusion: Cephalometry can be used to delineate factors such as C1 vertebral abnormalities, excessive pharyngeal depth, and short velum that contribute to VPD in VCFS. This would help otolaryngologists better understand the anatomy prior to surgical treatment of VPD. This is the first study to highlight the frequent occurrence of C1 anterior arch abnormalities in VCFS., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc., Rhinological, and Otological Society, Inc.)

In cadaveric studies and recently in one adult patient the occipital condyle has been studied as an option to allow bone purchase by fixation devices. In the current case the authors describe the use of occipital condyle screws in a child undergoing occipitocervical fixation. To the best of the authors' knowledge this case is the first reported instance of this technique in a pediatric patient. This girl had a history of posterior fossa decompression for Chiari malformation Type I when she was 22 months of age. When she was 6 years old she presented with neck pain on flexion and extension of her head. Magnetic resonance imaging in flexion and extension revealed occipitocervical instability. She underwent an occiput to C-2 posterior arthrodesis with bilateral screw placement in the occipital condyles, C-2 lamina, and C-1 lateral masses. Postoperatively, she was neurologically intact. Computed tomography demonstrated a stable construct, and her cervical pain had resolved on follow-up.

A 27-year-old woman presented with bilateral weakness of her all extremities for 5 years. She had a spastic gait and was unable to ambulate without assistance. Neurologic examination revealed increased deep tendon reflexes and positive pathologic reflexes. Radiographs showed occipitalization of the atlas, C2-C3 congenital fusion and fixed atlantoaxial dislocation with an atlanto-dental interval of 10 mm. MRI demonstrated cervicomedullary junction (CMJ) compression from the odontoid, a Chiari type I malformation, and syringomyelia extending from the foramen magnum to C5. The patient underwent transoral atlantoaxial release followed by posterior internal fixation from the occiput to the axis, which resulted in a significant improvement in motor function in all extremities. Post-operative images showed anatomical reduction of the atlantoaxial joint. However, an MRI performed 8 days following surgery showed a new retro-odontoid pannus had developed that was compressing the spinal cord at CMJ. A follow-up CT scan performed at 6 months post-operatively demonstrated a solid bony fusion between the occiput and C2, while an MRI at that time showed complete resolution of the retro-odontoid soft tissue mass with correction of the Chiari I malformation, and resolution of the syringomyelia. Final follow-up at 2-years revealed an excellent clinical outcome.

Objective: To review our experience with the surgical management of craniovertebral junction malformations, focusing on the selection of surgical approach, management of the associated Chiari malformation, and postoperative instability., Methods: During a 7-year period (May 2000-May 2007), 34 patients with a mean age of 55 years (age range, 32-75 years) underwent transoral surgery for fixed or nearly fixed ventral compression at the craniovertebral junction caused by basilar invagination and/or atlantoaxial dislocation. Chiari malformation was detected in 13 patients. The most common presenting signs were motor deficits (88%), followed by sensory loss (35%). All patients but one who had posterior stabilization performed elsewhere underwent single-stage anterior decompression and posterior occipitocervical fixation. Adjuncts to the transoral approach were tailored to the local anatomy (severity of basilar invagination, extent of mandibular excursion) found in each patient. Posterior fossa decompression was performed in 3 patients with Chiari malformation., Results: Thirty-one patients were alive at the time of the last follow-up evaluation (average, 3.7 years; range, 0.5-7.5 years). Of the 28 surviving patients admitted with preoperative motor impairment, 24 patients (86%) improved at least 1 Nurick grade, whereas the grade did not change in 4 (14%) patients. There were 2 (6%) perioperative deaths, and 1 other patient died subsequently of causes unrelated to surgery. Surgical morbidity was 18% and included dural laceration, cerebrospinal fluid leak with meningitis, malocclusion, oral wound dehiscence, and occipital wound infection. Delayed instability occurred in 1 patient because of cranial settling of the C2 vertebral body., Conclusion: Successful decompression of the abnormal craniovertebral junction requires extensive preoperative evaluation, appropriate tailoring of the operative approach, and an adequate learning curve. Transmaxillary approaches are useful adjuncts to the transoral approach in patients with severe basilar invagination or in cases of limited jaw mobility. Anterior decompression has been proven effective in relieving obstruction of the subarachnoid space at the foramen magnum in most patients with associated Chiari malformation.

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.

Osteogenesis imperfecta (OI) is a disorder of bone development caused by a genetic dysfunction of collagen synthesis. Basilar invagination (BI) is an uncommon but serious complication of OI. Brainstem decompression in OI is undertaken in certain circumstances. Transoral-transpalatopharyngeal ventral decompression with posterior occipitocervical fusion has become the treatment of choice when required. This technical note outlines a novel endoscopic transnasal approach for ventral decompression. The literature is reviewed and a strategy for the management of BI in patients with OI is outlined.

Object: Basilar impression (BI) secondary to osteogenesis imperfecta (OI) is a rare but debilitating condition that is often progressive unless it is halted. More recently, ventral decompression surgery has been advocated for this condition. This study is a retrospective review of the 21-year experience of ventral decompression surgery and dorsal occipitocervical fixation in patients with BI secondary to OI and is the largest patient series reported to date., Methods: Twenty patients treated between 1982 and 2003 by the senior author at the authors' institution were included in this study. All patients underwent ventral decompression surgery followed by dorsal craniocervical stabilization. Patients were followed up for a median of 10 years., Results: There were no intraoperative or perioperative deaths. Postoperatively, 16 of 20 (80%) patients showed objective improvement or maintained their good preoperative level of function. After surgery, of the 15 patients admitted with Karnofsky Performance Scale (KPS) scores of 70% or less, 11 improved, two remained unchanged, one patient's condition deteriorated, and one patient died of an unrelated cause. Of five patients admitted with a KPS score of 80% or greater, no patient's condition deteriorated in the short- and midterm period, but one patient had recurrence 15 years after surgery. At the end of follow-up, 25% of the patients had recurrence of brainstem compression symptoms or had died, and 15% showed no improvement after surgery. All of the remaining patients (60%) had sustained a long-term benefit from surgery., Conclusions: Aggressive ventral decompression surgery and dorsal stabilization for patients with BI secondary to OI can not only halt disease progression but can also produce a good and sustainable long-term functional outcome, even in those patients who present as severely symptomatic. Patients who presented early with minor symptoms had good long-term outcomes.

There are numerous congenital anomalies of the cervical spine. They can be simple and clinically inconsequential to complex with serious neurologic and structural implications. They can occur in isolation or as one of several maldeveloped organs in the patients. Many are discovered incidentally. The more common anomalies seen by pediatric spine surgeons include defects of the anterior or posterior arches of C1, occipital assimilation of the atlas, basilar invagination or impression, os odontoideum, and Klippel-Feil syndrome. Management begins with a detailed history, physical examination, and imaging studies. In general, those lesions that are causing or have caused neurologic injury, chronic pain, or spinal deformity or place the patient at high risk for developing these require treatment.

Symptomatic irreducible basilar invagination has traditionally been approached through a transoral-transpharyngeal route with resection of the anterior portion of C-1 and the odontoid. Modification of this exposure with either a Le Fort osteotomy or a transmandibular osteotomy and circumglossal approach has increased the access to pathological conditions in this region. These traditional routes all require traversing the oral cavity and accepting the associated potential complications. The authors have developed a novel surgical approach, an endoscopic transcervical odontoidectomy, which allows access for resection of the odontoid and for brainstem and spinal cord decompression without traversing the oral cavity. In this paper they describe the technique and its advantages and present three cases in which patients underwent the endoscopic transcervical odontoidectomy for basilar invagination. Three consecutive patients (age range 42-74 years) who had irreducible basilar invagination underwent the endoscopic transcervical odontoidectomy. All were symptomatic and had neck pain and myelopathy. All were evaluated preoperatively and postoperatively with computed tomography and magnetic resonance imaging. In all cases the procedure resulted in complete decompression. There were no serious complications. No patient required prolonged intubation, tracheostomy, or enteral tube feeding. One patient had an intraoperative cerebrospinal fluid leak, which had no postoperative sequelae. The authors present an alternative surgical approach for treating ventral compression of the brainstem and spinal cord. The technique is safe and effective for decompression and provides a surgical route that can be added to the armamentarium of treatments for pathological conditions in this region.

We report on a 48 years-old man with basilar impression without syringohydromyelia, in which the cisterna magna was impacted by the cerebellar tonsils. Six months after posterior fossa decompression there was the disappearance of nuchal rigidity, vertigo, spastic paraparesis and improvement of balance. Nevertheless hyperreflexia and diminished pallesthesia of the lower limbs persisted.

Study Design: The authors report a case of a patient with diffuse idiopathic skeletal hyperostosis (DISH) associated with basilar impression resulting in tetraparesis., Objective: To describe neurologic compromise associated with DISH., Summary of Background Data: Neurologic deficits due to DISH are very rare, and only 1 case of basilar impression associated with DISH has previously been reported in the literature., Methods: Diagnosis was confirmed by radiograph and MRI, which demonstrated basilar impression associated with a hyperintense signal in the spinal cord on T2-weighted sequences. Transoral resection of the dens associated with posterior occipitocervical fixation was performed during the same anesthesia., Results: Postoperative outcome demonstrated regression of the pyramidal signs without recovery of unassisted walking., Conclusion: Early MRI should be performed in the evidence of spinal cord suffering in patients with DISH. Transoral approach allowed a good decompression of the spinal cord.

Two patients presented with congenital basilar invagination manifesting as progressive myelopathy. Both patients underwent surgery using a neuronavigation-assisted transoral-transpharyngeal approach. The Brain-LAB Vector Vision navigation system was used for image guidance. The registration accuracies were 0.9 and 1.3 mm. After decompression, posterior stabilization was performed. Both patients had an uneventful postoperative course. The transoral-transpharyngeal approach with the neuronavigation system provides safe exposure and decompression for basilar invagination.

Introduction: We report a case of a 52-years old women with Paget's disease. A secondary symptomatic basilar impression was observed, causing quadriparesis, bulbar palsy and ataxia, Clinical Presentation: We report a case of a 52-year old woman with history of/periodic headache. In the last 6 months the complaints became more intensive and continuous. Additionally quadriparesis, disphagia, hoarsness and gait instability occurred. A cranial form of Paget's disease was found and a secondary basilar impression with compression of the cerebellum and brain stem was proven. A median suboccipital decompression and C1 laminectomy were performed. The occipital bone was thick, porous, with lacunas full of blood, causing unusually intensive hemorrhage. The postoperative period was uneventful with resolution of the preoperative symptomatology., Conclusion: In cases with Paget's disease a secondary basilary impression with ensuing cerebellar and brain stem compression may be observed. Decompressive suboccipital craniectomy may be a therapeutic option. The surgical team should be prepared for an excessive hemorrhage from the porous occipital bone.

Purpose: To confirm the accuracy of the standard parameters of Chamberlain's line, McGregor's line, McRae's line, and Ranawat's line in the diagnosis of basilar impression in a normal Asian population using magnetic resonance imaging (MRI) scans of the craniocervical junction, and to evaluate the use of MRI in the initial diagnosis of basilar impression., Methods: We retrospectively reviewed MRI scans of the craniocervical junction in 114 Thai patients (61 men and 53 women) aged 20 to 89 years to assess the lines of Chamberlain, McGregor, McRae, and Ranawat. Patients with injury, tumour, or metastasis in the craniocervial junction; congenital anomalies; or clinical symptoms and signs of basilar impression were excluded., Results: 39 of the 114 patients had the odontoid tip extended above Chamberlain's line by 1 mm to 9 mm (mean, 2.89 mm). Only 7 men and 5 women had the tip of the odontoid process extended beyond the normal range of 5 mm. The mean distance of the odontoid tip extended past McGregor's line in male and female subjects was 0.33 mm (standard deviation [SD], 1.2 mm) and 0.17 mm (SD, 0.7 mm), respectively, markedly less than those reported previously, although one male patient's odontoid tip extended 8 mm above the McGregor's line. Regarding McRae's line, no patient had the odontoid tip extended above the foremen magnum. The mean Ranawat's line in male and female subjects was 15.75 mm (range, 12-19; SD, 1.71 mm) and 14.09 mm (range, 11-17; SD, 1.38 mm), respectively., Conclusion: After using MRI to confirm the standard parameters of basilar impression as previously formulated from lateral skull radiographs, we recommend using McRae's line and Ranawat's line in the initial screening for basilar impression for the Asian population. Chamberlain's line and McGregor's line are viable alternatives, but clinicians must be aware of the potential for false positives.

Study Design: The issue of progression of congenital basilar invagination is evaluated on the basis of 3 clinical cases. The rationale of treatment of basilar invagination in general and, particularly, in the complex clinical situation encountered in the presented cases, by the authors' technique of atlantoaxial joint distraction, reduction of basilar invagination, and direct lateral mass plate and screw fixation is discussed., Objective: The subject of progression of congenital basilar invagination and recurrent craniocervical cord compression after an initial transoral decompression is analyzed, and an alternative surgical treatment involving craniovertebral bone realignment is suggested., Summary of Background Data: This is a review of 3 cases of basilar invagination treated earlier by transoral decompression. No fixation procedure was performed. The patients presented with recurrent symptoms of high cervical cord compression. Investigations revealed a progression of basilar invagination and cord compression. The treatment of such a complex clinical situation by atlantoaxial joint distraction is discussed., Methods: Between September 2001 and January 2004, we treated 3 patients with congenital basilar invagination who underwent transoral odontoidectomy but did not undergo any posterior atlantoaxial or occipitoaxial fixation. The patients had postoperative improvement but worsening of their neurologic condition after an average duration of 26 months after transoral surgery. Repeat investigations revealed that basilar invagination and the craniovertebral alignments worsened during the period, and there was recurrent cervicomedullary cord compression. These patients were treated by atlantoaxial facet distraction, and attempts were made toward reduction of the basilar invagination and craniovertebral junction bony realignment, and atlantoaxial fixation by the technique recently described by us., Results: During the average follow-up of 25 months, all 3 patients have had a neurologic recovery., Conclusions: The probable cause of basilar invagination and its progression is a congenital malformation ofalignment of the facets of the atlantoaxial joint. Distraction of the facets and direct interarticular atlantoaxial fixation presents a unique opportunity of reduction of the basilar invagination and fixation of the region.

Background and Purpose: Platybasia, or abnormal obtuseness of the basal angle, was first measured on plain skull images. At present, evaluation of the brain and skull more commonly involves CT and MR imaging. We evaluated a new MR imaging method of evaluating platybasia., Methods: We retrospectively evaluated midline sagittal MR images in 200 adults and 50 children. The basal angle of the skull base was measured by using two methods: The standard MR imaging technique measured the angle formed by two lines-one joining the nasion and the center of the pituitary fossa connected by a line joining the anterior border of the foramen magnum and center of the pituitary fossa. The modified technique measured the angle formed by a line across the anterior cranial fossa and dorsum sellae connecting a line along the clivus., Results: With the standard MR imaging technique, we obtained mean angles of 129 degrees +/- 6 degrees for adults and 127 degrees +/- 5 degrees for children, compared with 135.3 degrees (composite mean) in previous series. The modified technique produced values of 117 degrees +/- 6 degrees for adults and 114 degrees +/- 5 degrees for children, which were significantly lower that those of standard MR imaging and traditional radiography (P <.05)., Conclusion: Both the standard and modified MR imaging techniques produced basal angles lower than those previously reported with standard radiography. The modified technique uses clearly featured landmarks that can be reproduced consistently on midline sagittal T1 images. This technique and its corresponding values can be used as the new standard for evaluating the basal angle.

Objective: Some have proposed that the calvarial thickening seen in patients with rickets results in an increased rate of Chiari I malformation (CIM) in these patients. The present study measures the posterior fossa volume in children with rickets to verify previous case reports indicting a small posterior fossa as the cause for an increased rate of CIM in children with rickets., Methods: Patients were chosen by use of a computer database to search for individuals diagnosed with rickets. Nineteen patients were identified with this diagnosis. Seven patients were found from this cohort to have imaging of the head. Axial computed tomographic and magnetic resonance images were analyzed by use of the Cavalieri method to define posterior fossa volumes. These data were then compared with those from age-matched control subjects., Results: Mean volumes of the posterior fossa were significantly reduced in all patients compared with age-matched control subjects (P < 0.0001)., Conclusion: We have found that the volume of the posterior fossa is significantly smaller in children with rickets versus age-matched control subjects. Furthermore, 29% of our study group had an associated CIM. We may hope that these data will aid in the further understanding of the pathophysiology of CIM in cases of metabolic bone disease.

We analyze the results of surgical treatment of 60 patients presenting syringomyelia (SM) associated with Chiari malformation (CM) who were operated in the period 1982-2000. For each case, analysis covered 15 signs and 16 symptoms included in a protocol that separated SM signs and symptoms from those of CM. A score system was established in parallel with the protocol to make the evaluation of treatment results easier. All cases were submitted to craniovertebral decompression by C1 and eventually C2 laminectomy and cerebellar tonsillectomy with duramater graft. To evaluate the results, statistical proportion difference tests and variance analyses were made to a reliability index of 95% (p=0.05). We conclude that the statistical improvement of CM signs and symptoms was very significant (p=0). Syringomyelia signs and symptoms also improved significantly, except for "upper limb hyporeflexia", which did not improve. No statistical difference in the improvement of SM symptoms as compared to CM symptom was found. Syringomyelia signs improved statistically more than CM signs. In half of patients, the percent improvement of signs and symptoms ranged between 40% and 60%.

Schwartz-Jampel syndrome is a rare, inherited disorder characterized by myotonia, skeletal deformities, facial dysmorphism, and growth retardation. In this report of an adolescent male patient with Schwartz-Jampel syndrome, CT and MR imaging revealed basilar invagination, platybasia, Chiari I malformation, hyperpneumatized mastoids with intramastoid dural sinuses, platyspondyly, bulbous zygoma, and blunted pterygoid processes.

Objective: To determine on radiographs the presence of Basilar Impression (BI) in children with Osteogenesis Imperfecta (OI). To confirm this sign and altered geometrical relationships of the craniocervical junction in course of time with magnetic resonance imaging (MRI)., Methods and Patients: In a cohort study of 130 patients with OI (OI type I: 85; OI type III: 21; OI type IV: 24) lateral radiographs of the skull and cervical spine were made in a standardised way. MRI scans were performed when BI was suspected based upon protrusion of the odontoid above Chamberlain's line. Intracranial abnormalities as well as the basal angle were described. Neurological examination was performed in patients with conclusive BI at MRI-scan., Results and Discussion: In eight patients BI could be confirmed by MRI-scan. None of the children had or developed in time neurological symptoms or signs. Follow up of BI by MRI scans was done in seven patients (mean: 5 years; range: 2-6 years). No alteration of intracranial findings were seen at subsequent investigation, although in one child Chamberlain's line increased from 8 (first MRI) to 15 mm (last MRI). BI can be diagnosed by radiographs but in the extreme osteoporotic bone and altered anatomy of the craniocervical junction of children with OI MRI is preferable. As intracranial pathology can be demonstrated by MRI, also a relation can be laid to possible neurological symptoms and signs at clinical examination., Conclusion: In our cohort study no alteration of the intracranial contents was seen at subsequent MRI scans. Although anatomic deformations exist in BI, no neurological symptoms or signs were present in our study and no operative reconstruction had to be performed. Periodical MRI-scan has not been of influence on the clinical decision making process. At the moment we perform a MRI-scan if BI is suspected at lateral skull radiographs. The MRI images serve as reference findings to anticipate on possible future symptoms and signs of neurological deficit.

Study Design: A case report of craniocervical spine lesions including basilar impression, atlantoaxial dislocation, and syringomyelia, with osteogenesis imperfecta is presented, and the literature is reviewed., Objective: To discuss the problems involved in the surgical management of craniocervical spine lesion with osteogenesis imperfecta., Summary of Background Data: Osteogenesis imperfecta is known to have various spine lesions as complications. However, few reports have described craniocervical lesions associated with osteogenesis imperfecta., Methods: A 14-year-old girl with osteogenesis imperfecta, Silence classification IVB, experienced difficulty walking, with marked motor disturbance and muscle weakness in the extremities. Deep tendon reflexes were exaggerated bilaterally in the upper and lower extremities, and positive Babinski reflex and ankle clonus were observed bilaterally. Basilar impression, atlantoaxial dislocation, and syringomyelia were shown by plain radiography, tomography, three-dimensional computed tomography, and magnetic resonance imaging., Results: In the reported patient, posterior fossa decompression and atlantoaxial posterior fusion could not be performed because the foramen magnum and upper cervical spine invaginated to the base of the skull. Therefore, occipitocervical spine fusion using titanium loop and wires was performed at the reduced position of the atlantoaxial dislocation, resulting in improvement of neurologic deficits., Conclusions: For patients with atlantoaxial dislocation, syringomyelia, and basilar impression without clinical symptoms or signs of brain stem compression, occipitocervical spine fusion alone at the reduction of the atlantoaxial dislocation may be indicated because these procedures improve neurologic deficits and prevent postoperative development of basilar impression and enlargement of syringomyelia.

A case of spontaneous occipitocervical fusion is discussed. The authors believe that fusion at the occipitocervical junction will occasionally occur in rheumatoid arthritis in the adult population. As a result of fusion, the dens axis is unable to exert compression on the spinal cord with increased neck flexion.

The discovery of a craniocervical junction malformation requires management in three steps: (1) The patterns must be recognized using tomographic measurements (Chamberlain's line, Wackenheim's line). Dynamic flexion-extension studies are necessary to assess stability or instability. Stable patterns range from platybasia to basilar invagination, with gradual deformation, and are frequently associated with Chiari malformation. Unstable patterns characterized by odontoid instability are the equivalent of an odontoid fracture. The origin is malformative (hypoplasia, aplasia of the dens, os odontoidum), but the last may be difficult to distinguish from an old odontoid fracture. They are found in many syndromes (Down, Morquio, etc.). Unstable atlantoaxial patterns with atlas assimilation are hardly reducible; they evolve toward progressive instability. (2) The neurological consequences must be defined from the clinical features of the spinal cord and the cranial nerves. Both static and dynamic MRI scans must be performed; in this way identification of the neural abnormalities (hydromyelia, Chiari, etc.) and of the osseous compression is possible. (3) The most appropriate operative procedure must be selected: stable platybasia with a nervous compression by Chiari is cured only by posterior decompression; odontoid instability is cured by reduction and posterior fixation, using hooks and autologous bone grafts on the posterior arches of C-1 and C-2. Sometimes a transarticular screw fixation of C1-2 is necessary if there is a defect on the C-1 posterior arch. Craniocervical dislocations with assimilation of the atlas require posterior occipito-vertebral bony fixation with grafts and external halo immobilization or internal fixation with hooks or screws, with anterior transoral decompression in a second step.

We report a boy who developed a vertebral stroke immediately after an appendectomy. Basilar impression was diagnosed eight years after this event when skull roentgenograms revealed basilar impression with high standing tip of the odontoid. We speculate that muscle relaxation and cervical hyperextension during intubation in the presence of basilar impression resulted in vertebral artery dissection and stroke. We suggest that patients with vertebral stroke and no obvious risk factors should be evaluated for the presence of malformations of the craniovertebral junction to be able to take precautions against excessive neck movement during intubation.

Object: The authors analyzed the cases of 163 patients with syringomyelia to assess the appropriate surgical procedure., Methods: Depending on the aetiological factors and treatment considerations the series was classified into three groups. Group I were cases where there was no definite demonstrable aetiological factor; Group II cases had basilar invagination and/or Chiari malformation; and Group III consisted of cases where the syrinx was secondary to an obvious aetiology, such as a mass lesion either in the posterior cranial fossa or in the spine or a severe kyphotic spinal deformity. Post-traumatic syringomyelia and syrinx in association with spina bifida were not studied., Conclusions: We concluded that for Group I cases syringosubarachnoid shunting is the ideal form of treatment. In Group II cases foramen magnum bony decompression is satisfactory and physiological. Good results were obtained even in cases where either a foramen magnum decompression alone or in combination with a syringo-subarachnoid shunt was done. Only syringosubarachnoid shunt (without a foramen magnum decompression) in Group II cases was found to produce poor outcome. Group III cases should be treated for the primary aetiological problem. Only syrinx drainage procedure without treatment of aetiology in these cases produced poor results. It was observed that clinical outcome rather than radiological improvement is the reliable indicator of the surgical result.

Neurofibromatosis type 1 (NF1) can virtually affect any organ, presenting most frequently with "cafe au lait" spots and neurofibromas. Vasculopathy is a known complication of NF1, but cerebrovascular disease is rare. We report the case of a 51-year-old man admitted to the hospital with a history of stroke four months before admission. On physical examination, he presented various "cafe au lait" spots and cutaneous neurofibromas. Neurologic examination demonstrated right-sided facial paralysis, right-sided hemiplegia, and aphasia. Computed tomography scan of head showed hypodense areas in the basal ganglia and centrum semiovale. Radiographs of cranium and cervical spine showed basilar impression. Angiography revealed complete occlusion of both vertebral and left internal carotid arteries, and partial stenosis of the right internal carotid artery. A large network of collateral vessels was present (moyamoya syndrome). It is an uncommon case of occlusive cerebrovascular disease associated with NF1, since most cases described in the literature are in young people, and tend to spare the posterior cerebral circulation. Basilar impression associated with this case may be considered a pure coincidence, but rare cases of basilar impression and NF1 have been described.

Severe basilar impression leads to an upward translocation of the upper cervical spine and clivus into the foramen magnum and is a diagnosis best made with computed tomography or magnetic resonance imaging scans. Basilar impression may be a primary condition or secondary to bone softening disorders. Symptoms relating to direct neuraxial compression, obstruction to cerebral spinal fluid outflow, and vascular compromise all have been described. Management depends on the exact nature of the abnormality seen, but it is now firmly accepted that those with anterior neuraxial compression should have an anterior decompression. The severe basilar impression and craniofacial abnormalities seen in osteogenesis imperfecta together with the progressive nature of the condition have led to the development of a specific surgical response, the open door maxillotomy combined with a contoured loop fixation of the cervical spine. Little is known of the long term outcome of severe basilar impression, and long term studies undertaken by centers familiar with the condition and its management are required if definitive care is to be delivered to these patients.

A 47-year-old male presented with abducens nerve palsy due to basilar impression associated with atlanto-occipital assimilation manifesting as slowly progressive bilateral trigeminal neuralgia and diplopia in the right lateral gaze. X-ray and computed tomography of the skull confirmed the diagnosis of basilar impression and atlanto-occipital assimilation, and magnetic resonance imaging disclosed tightness of the posterior cranial fossa. Surgical suboccipital decompression resulted in gradual resolution of the patient's complaints, and no additional symptoms were recognized. Impairment of the sixth cranial nerve is a rare symptom compared to those of the fifth or the eighth cranial nerve in a patient with a craniocervical malformation. However, the present case shows the possibility of cranial nerve dysfunction due to tightness of the posterior cranial fossa, and suggests that surgical treatment for basilar impression with atlanto-occipital assimilation should be considered in patients with uncommon and unusual symptoms.

A 43-year-old woman presented with dull headache, left tinnitus and dizziness. Neurological examination revealed down-beat gaze nystagmus, left tinnitus, positive Romberg sign, poor standing on the left foot, poor tandem gait, left spastic gait and positive pathological reflexes in the bilateral upper and lower extremities. Plain X-ray of the skull and cervical vertebrae demonstrated basilar impression and atlantoaxial fusion. Magnetic resonance imaging of the brain and cervical spine showed cerebellar tonsil descent and syringomyelia located in the left side of the spine at the II-III vertebral level which communicated with the fourth ventricle. The patient was diagnosed as having cervical syringomyelia. Arnold-Chiari type I malformation and basilar impression. Preoperative polysomnography showed dysrhythmic breathing and bradypnea during sleep. Abnormal breathing improved after suboccipital decompression craniotomy and upper cervical laminectomy. It was suggested that dysrhythmic breathing was caused by a disorder of the medullary respiratory center. Herniation of the cerebellar tonsil and syringomyelia might have compressed the medulla.

Current therapy of basilar impression includes transoral dens resection. The essential disadvantage of this procedure is the instability of C1/C2 due to loss of the transverse ligament. We describe two patients in whom this instability was treated by modified screwing. Using MAGERL-screws between C0-C2 an interposition of an iliac graft between the occiput and the arc of C2 was made. Neurological symptoms improved in both patients postoperatively. In both cases stable fusion C0/C2 was achieved with an additional treatment with a HALO-fixateur for eight weeks. In our opinion the combined transoral/dorsal procedure is most suitable and efficient in treatment of basilar impressions. By this approach both, decompression of the myelon as well as stable fusion C0/C2, is achieved.

The patient, a 78-year-old female with history of headache and progressive gait disturbance for almost one year, was admitted to our department because of dysphagia and dysphonia since three months before. Neurological examination revealed nystagmus, cerebellar ataxia, deafness, and vesical incontinence. No cerebral injuries were detected by computed tomography (CT) scan, although Paget's. Disease of Bone (PDB) was suggested, confirmed by biochemical and scintigraphic studies. The plain skull X-ray showed platybasia. As all the disarrangements were not explained by PDB complications alone, nuclear magnetic resonance imaging (MRI) was performed which demonstrated an Arnold-Chiari malformation (ACM) type I, with mild tonsillar herniation and anterior compression of the brainstem due to basilar impression, without syringomyelia. The association of PDB and ACM is a peculiarity seldom reported. The surgical approach was rejected, but the severity of symptoms and osteitis deformans biochemical activity needed a treatment; it was orientated to modify bone turnover using etidronate, a bisphosphonate, which induced clinical improvement and a decrease in serum alkaline phosphatase as well as in other bone resorption markers, without side effects. The good status and biochemical remission have been maintained a year later.