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Children (Basel, Switzerland) Jun 2023Osteogenesis Imperfecta (OI) is a disease that causes bone fragility and deformities, affecting both the cranial base and the craniocervical junction, and may lead to...
Osteogenesis Imperfecta (OI) is a disease that causes bone fragility and deformities, affecting both the cranial base and the craniocervical junction, and may lead to other neurological disorders. A retrospective cross-sectional study was carried out based on cephalometric analysis of the cranial base in a sample of patients with OI, in lateral skull radiographs and magnetic resonance imaging (MRI), comparing them with a sample of age-matched controls. When the different variables of the craniocervical junction were analyzed, significance was found in comparisons with the different age groups. All measurements of the variables studied stabilized as growth progressed. For most of the variables, the severity of the disease influences the measurements of the skull base, with statistically significant differences. Both age and severity of the disease are factors that directly influence the anatomy of the craniocervical junction in these patients and may serve as indicators in the early detection and prevention of other derived alterations.
PubMed: 37371261
DOI: 10.3390/children10061029 -
Spine Jun 2024Retrospective study.
STUDY DESIGN
Retrospective study.
OBJECTIVE
To evaluate the feasibility of C2 pedicle screw fixation with the "in-out-in" technique in patients with basilar invagination (BI).
SUMMARY OF BACKGROUND DATA
The "in-out-in" technique is a fixation technique in which the screw enters the vertebrae through the parapedicle. The technique has been used in upper cervical spine fixation. However, anatomic parameters associated with the application of this technique in patients with BI are unclear.
MATERIALS AND METHODS
We measured the C2 pedicle width (PW), the distance between the vertebral artery (VA) and the transverse foramen (VATF), the safe zone, and the limit zone. The lateral safe zone is the distance from the medial/lateral cortex of the C2 pedicle to the VA (LPVA/MPVA), and the medial safe zone is the distance from the medial/lateral cortex of the C2 pedicle to the dura (MPD/LPD). The lateral limit zone is the sum of LPVA/MPVA and VATF (LPTF/MPTF), and the medial limit zone is the distance from the medial/lateral cortex of the C2 pedicle to the spinal cord (MPSC/LPSC). PW, LPVA, MPVA, and VATF were measured on the reconstructed CT angiography. PW, MPD, LPD, MPSC, and LPSC were measured on MRI. We define a width greater than 4 mm as safe for screw. The t -test was used to compare the parameters between male and female, left and right sides in all patients, and PW in CTA and MRI data in the same patient. For intrarater reliabilities, interclass correlation coefficients were calculated.
RESULTS
A total of 154 patients (49 CTA, 143 MRI) were included. The average PW, LPVA, MPVA, LPTF, MPTF, MPD, LPD, MPSC, and LPSC were 5.30 mm, 1.28 mm, 6.60 mm, 2.45 mm, 8.94 mm, 2.09 mm, 7.07 mm, 5.51 mm, and 10.48 mm, respectively. Furthermore, in patients with PW <4 mm, 53.6% of MPVA, 86.2% of LPTF, and all limit zones were larger than 4 mm.
CONCLUSIONS
In patients with BI, there is sufficient space medially and laterally to the C2 pedicle for partial screw encroachment to achieve "in-out-in" fixation, even if the pedicle is small.
LEVEL OF EVIDENCE
Level-4.
Topics: Humans; Male; Pedicle Screws; Female; Feasibility Studies; Retrospective Studies; Adult; Middle Aged; Cervical Vertebrae; Spinal Fusion; Aged; Platybasia; Young Adult; Treatment Outcome; Vertebral Artery
PubMed: 37339267
DOI: 10.1097/BRS.0000000000004757 -
Clinical Neurology and Neurosurgery Jul 2023To present our experience with an individualized surgical approach to treat Chiari malformation type 1.
OBJECTIVE
To present our experience with an individualized surgical approach to treat Chiari malformation type 1.
METHODS
Based on (1) neurological symptoms, (2) the existence and extent of a syrinx and (3) the degree of the tonsillar descent we performed four types of approaches on a case-by-case basis in 81 patients: (1) foramen magnum decompression (FMD) with dura splitting (FMDds); (2) FMD with duraplasty (FMDdp); (3) FMD with duraplasty and tonsillar manipulation (FMDao); and (4) tonsillar resection/reduction (TR). Patient characteristics, Chiari Severity Index (CSI), fourth ventricular roof angle (FVRA) and Chicago Chiari Outcome Scale (CCOS) were analyzed.
RESULTS
CCOS was between 13 and 16 points in 8/11 (73 %) patients after FMDds, 38/45 (84 %) patients after FMDdp, and 24/24 (100 %, one patient lost to follow-up) patients after TR. We experienced an overall complication rate of 13.6 % (11/81) in this series, whereas seven of these eleven complications (64 %) occurred in the FMDao group and the complication rate increased with the invasiveness of the approach (0 % FMDds; 4 % FMDdp; 12 % TR).
CONCLUSION
Given the clear correlation between the extend of the approach and the complication rate the least invasive approach necessary to achieve clinical improvement should be selected. Due to the high complication rates, FMDao should not be used as a treatment option. The severity of the tonsillar descent, basilar invagination and current CM1 scores could be used to aid in the approach selection.
Topics: Humans; Treatment Outcome; Decompression, Surgical; Magnetic Resonance Imaging; Arnold-Chiari Malformation; Platybasia; Foramen Magnum; Retrospective Studies
PubMed: 37245455
DOI: 10.1016/j.clineuro.2023.107803 -
World Neurosurgery Jul 2023Patients with Chiari malformation (CM) associated with atlantoaxial dislocation (AAD) and basilar invagination (BI) may present with a small posterior cranial fossa, but...
OBJECTIVE
Patients with Chiari malformation (CM) associated with atlantoaxial dislocation (AAD) and basilar invagination (BI) may present with a small posterior cranial fossa, but data on the volumetric analysis are lacking. Additionally, whether additional foramen magnum decompression (FMD) is needed together with atlantoaxial fusion remains controversial. This study evaluated the volumetric alterations of the posterior cranial fossa in these patients and analyzed the radiological and clinical outcomes after posterior C1-C2 reduction and fixation plus C1 posterior arch resection.
METHODS
Thirty-two adult CM patients with AAD and BI (CM-AAD/BI group) and 21 AAD and BI patients without CM (AAD/BI-only group) who received posterior atlantoaxial fusion plus C1 posterior arch resection were retrospectively studied. The clinical and radiological outcomes and volumetric measurements of the posterior cranial fossa were evaluated.
RESULTS
The majority of CM-AAD/BI patients (94%) improved clinically and radiologically at 12 mo postoperatively, and none required additional FMD. Morphological analysis revealed a significant reduction in the bony posterior cranial fossa volumes of the CM-AAD/BI group (P < 0.01) and the AAD/BI-only group (P < 0.01) relative to those of the CM group. No significant differences were observed between the CM-AAD/BI and AAD/BI groups.
CONCLUSIONS
Compared with patients with simple CM, patients with AAD/BI with or without CM demonstrated a considerably and equally reduced bony posterior cranial fossa volume. No additional FMD is needed in the treatment of CM-AAD/BI patients after posterior reduction and fusion plus C1 posterior arch resection.
Topics: Adult; Humans; Retrospective Studies; Arnold-Chiari Malformation; Platybasia; Joint Dislocations; Atlanto-Axial Joint; Decompression, Surgical; Neck Injuries; Spinal Fusion
PubMed: 37087038
DOI: 10.1016/j.wneu.2023.04.064 -
Operative Neurosurgery (Hagerstown, Md.) Aug 2023The correlation among syrinx resolution, occipitoaxial sagittal alignment, and surgical outcome in long-term follow-up seems to have not been clarified.
Correlation Among Syrinx Resolution, Cervical Sagittal Realignment, and Surgical Outcome After Posterior Reduction for Basilar Invagination, Atlantoaxial Dislocation, and Syringomyelia.
BACKGROUND
The correlation among syrinx resolution, occipitoaxial sagittal alignment, and surgical outcome in long-term follow-up seems to have not been clarified.
OBJECTIVE
To further explore the relationship between the syrinx resolution and occipitoaxial realignment after posterior reduction and fixation in basilar invagination (BI)-atlantoaxial dislocation (AAD) patients with syringomyelia.
METHODS
A continuous series of 32 patients with BI-AAD and syringomyelia who received direct posterior reduction met the inclusion criteria of this study. Their clinical and imaging data were analyzed retrospectively. Before surgery and at the last follow-up, we used the Japanese Orthopedic Association (JOA) score and the Neck Disability Index (NDI) to assess the neurological status, respectively. The Pearson correlation coefficient and multiple stepwise regression analysis were used to explore the relevant factors that may affect surgical outcomes.
RESULTS
There were significant differences in atlantodental interval, clivus-axial angle, occiput-C2 angle (Oc-C2A), cervicomedullary angle (CMA), subarachnoid space (SAS) at the foramen magnum (FM), syrinx size, NDI, and JOA score after surgery compared with those before surgery. ΔCMA and the resolution rate of syrinx/cord as relevant factors were correlated with the recovery rate of JOA (R 2 = 0.578, P < .001) and NDI (R 2 = 0.369, P < .01). What's more, ΔSAS/FMD (SAS/FM diameter) and ΔOc-C2A were positively correlated with the resolution rate of syrinx/cord (R 2 = 0.643, P < .001).
CONCLUSION
With medulla decompression and occipital-cervical sagittal realignment after posterior reduction and fusion for BI-AAD patients with syringomyelia, the structural remodeling of the craniovertebral junction and occipitoaxial realignment could contribute to syringomyelia resolution.
Topics: Humans; Syringomyelia; Retrospective Studies; Atlanto-Axial Joint; Joint Dislocations; Platybasia; Treatment Outcome
PubMed: 37083634
DOI: 10.1227/ons.0000000000000719 -
World Neurosurgery Jul 2023In this third article in a 3-article series on the craniocervical junction, we define the terms "basilar impression," "cranial settling," "basilar invagination," and...
In this third article in a 3-article series on the craniocervical junction, we define the terms "basilar impression," "cranial settling," "basilar invagination," and "platybasia," noting that these terms are often used interchangeably but represent distinct entities. We then provide examples that represent these pathologies and treatment paradigms. Finally, we discuss the challenges and future direction in the craniovertebral junction surgery space.
Topics: Humans; Platybasia; Skull; Decompression, Surgical
PubMed: 36990348
DOI: 10.1016/j.wneu.2023.03.098 -
World Neurosurgery May 2023To compare the measured odontoid tip violation above Chamberlain's line described in the literature to diagnose basilar invagination (BI) and to establish the normal... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To compare the measured odontoid tip violation above Chamberlain's line described in the literature to diagnose basilar invagination (BI) and to establish the normal placement of the dens tip defining individuals without BI (normal subjects).
METHODS
A systematic literature review was performed to identify clinical or radiological studies that expressed the amount of odontoid violation above Chamberlain's line in patients with a BI diagnosis. In addition, a meta-analysis was performed to evaluate normal subjects' values of Chamberlain's line violation (CLV).
RESULTS
There were 23 studies included (13 radiological and 10 clinical). Most studies used computed tomography and/or magnetic resonance imaging. Eight different cutoff values were used to measure dislocated odontoid apexes above Chamberlain's line regardless of the radiological modality. The mean measured amount of CLV was 3.95 mm (median 5 mm; range, 0-9 mm). The meta-analysis included 8 studies (1233 patients) with a normal sample population with a mean normal CLV of -0.63 mm (below the line) (95% confidence interval [-0.8, 1.18 mm], random effects model).
CONCLUSIONS
Different values were found in the assessed studies used for CLV in BI diagnosis. This variability is especially important for type B BI, as type A BI has other craniocervical diagnostic parameters. Considering the results obtained in this meta-analysis, BI should be diagnosed in the case of any dens violation >1.18 mm.
Topics: Humans; Platybasia; Radiography; Tomography, X-Ray Computed; Magnetic Resonance Imaging; Reference Values
PubMed: 36822399
DOI: 10.1016/j.wneu.2023.02.057 -
World Neurosurgery Apr 2023Type B basilar invagination (BI) refers to odontoid process prolapse into skull base without dislocation, which is often associated with Chiari malformation and...
Type B basilar invagination (BI) refers to odontoid process prolapse into skull base without dislocation, which is often associated with Chiari malformation and syringomyelia. Its pathogenesis and treatment are in controversy. Posterior fossa decompression has been introduced to treat the associated Chiari malformation; however, it may not be effective for symptoms with severe ventral nerve compression. C1-2 in situ fixation has been reported to treat minor instability in type B BI, yet the assessment of minor instability has not been widely accepted. We believe that the pathogenesis is chronic ventral compression of the brainstem. Transoral odontoidectomy is a classic surgical procedure to treat the pathogenesis, but it is associated with high risks of infection, velopharyngeal incompetence, and airway obstruction and often requires posterior surgery for fusion. Thus we use an interfacet distraction technique to move the odontoid process down and relieve ventral brainstem compression. Therefore interfacet structural support is necessary to maintain the distance of the interfacet. The reason for fixation is that interfacet distraction disrupts atlantoaxial stability. We designed a novel sliding-traction head holder, which can quantitatively tract and stabilize the head without support for the head or face, avoiding the risk of eyeball compression. It adapts to a variety of surgical methods and allows intraoperative changes in the patient's position. Assisted by the device, a satisfied interfacet distraction and a correction of BI were obtained. Video 1 describes how the interfacet distraction technique assisted by a sliding-traction head holder was performed in an illustrative case. The patient consented to the procedure.
Topics: Humans; Traction; Platybasia; Arnold-Chiari Malformation; Joint Dislocations; Decompression, Surgical; Spinal Fusion; Atlanto-Axial Joint
PubMed: 36736772
DOI: 10.1016/j.wneu.2023.01.033 -
Neurosurgery Apr 2023
Topics: Humans; Platybasia; Arnold-Chiari Malformation; Joint Instability; Atlanto-Axial Joint; Decompression, Surgical
PubMed: 36729751
DOI: 10.1227/neu.0000000000002312 -
European Spine Journal : Official... Jul 2023Malformations of the craniovertebral junction (CVJ) range from mild, asymptomatic conditions to severe forms of instability with basilar invagination. Rarely, there have...
PURPOSE
Malformations of the craniovertebral junction (CVJ) range from mild, asymptomatic conditions to severe forms of instability with basilar invagination. Rarely, there have been accounts of forms of so-called paramedian basilar invagination, with abnormal bone masses invading the lateral portion of the foramen magnum. All these entities have been comprehensively classified both from an anatomical and embryological standpoint.
METHODS
Here, we report a case of a unique CVJ malformation which is not included in any existing classification framework and could represent a novel pathologic entity. We also provide an overview of the pertinent literature.
RESULTS
The patient was a 14-year-old boy with a recent onset of spastic tetraparesis. Radiological studies documented a malformation of the atlas which invaginated through the foramen magnum, causing anterolateral medullary incarceration. Surgical treatment involved posterior decompression with resection of the abnormal bone and occipito-cervical fusion.
CONCLUSION
Our report enriches the panorama of CVJ malformations, showing how anatomical knowledge and embryological insights constitute the basis for the correct assessment and treatment of these complex entities.
Topics: Male; Humans; Adolescent; Foramen Magnum; Decompression, Surgical; Platybasia; Arnold-Chiari Malformation; Spinal Fusion
PubMed: 36527509
DOI: 10.1007/s00586-022-07500-8