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Neurosurgical Focus May 2024Skull base chordomas are rare, locally osseo-destructive lesions that present unique surgical challenges due to their involvement of critical neurovascular and bony...
OBJECTIVE
Skull base chordomas are rare, locally osseo-destructive lesions that present unique surgical challenges due to their involvement of critical neurovascular and bony structures at the craniovertebral junction (CVJ). Radical cytoreductive surgery improves survival but also carries significant morbidity, including the potential for occipitocervical (OC) destabilization requiring instrumented fusion. The published experience on OC fusion after CVJ chordoma resection is limited, and the anatomical predictors of OC instability in this context remain unclear.
METHODS
PubMed and Embase were systematically searched according to the PRISMA guidelines for studies describing skull base chordoma resection and OC fusion. The search strategy was predefined in the authors' PROSPERO protocol (CRD42024496158).
RESULTS
The systematic review identified 11 surgical case series describing 209 skull base chordoma patients and 116 (55.5%) who underwent OC instrumented fusion. Most patients underwent lateral approaches (n = 82) for chordoma resection, followed by midline (n = 48) and combined (n = 6) approaches. OC fusion was most often performed as a second-stage procedure (n = 53), followed by single-stage resection and fusion (n = 38). The degree of occipital condyle resection associated with OC fusion was described in 9 studies: total unilateral condylectomy reliably predicted OC fusion regardless of surgical approach. After lateral transcranial approaches, 4 studies cited at least 50%-70% unilateral condylectomy as necessitating OC fusion. After midline approaches-most frequently the endoscopic endonasal approach (EEA)-at least 75% unilateral condylectomy (or 50% bilateral condylectomy) led to OC fusion. Additionally, resection of the medial atlantoaxial joint elements (the C1 anterior arch and tip of the dens), usually via EEA, reliably necessitated OC fusion. Two illustrative cases are subsequently presented, further exemplifying how the extent of CVJ bony elements removed via EEA to achieve complete chordoma resection predicts the need for OC fusion.
CONCLUSIONS
Unilateral total condylectomy, 50% bilateral condylectomy, and resection of the medial atlantoaxial joint elements were the most frequently described independent predictors of OC fusion in skull base chordoma resection. Additionally, consistent with the occipital condyle harboring a significantly thicker joint capsule at its posterolateral aspect, an anterior midline approach seems to tolerate a greater degree of condylar resection (75%) than a lateral transcranial approach (50%-70%) prior to generating OC instability.
Topics: Humans; Chordoma; Skull Base Neoplasms; Occipital Bone; Spinal Fusion; Cervical Vertebrae; Female; Atlanto-Occipital Joint; Male; Adult; Middle Aged
PubMed: 38691866
DOI: 10.3171/2024.3.FOCUS248 -
Child's Nervous System : ChNS :... Jan 2024Autosomal dominantly inherited neurofibromatosis type I (NF1) is a systemic disorder caused by a mutation of a gene on chromosome 17q11.2 and characterized by multiple... (Review)
Review
Autosomal dominantly inherited neurofibromatosis type I (NF1) is a systemic disorder caused by a mutation of a gene on chromosome 17q11.2 and characterized by multiple café-au-lait spots, lentiginous macules, Lisch nodules of the iris, and tumors of the nervous system. Bony manifestations such as scoliosis, dysplasia of the greater sphenoidal wing, tibial pseudoarthrosis, short stature, and macrocephaly have been reported in approximately 50% of patients. However, calvarial bone defects are rare. After screening 324 articles, 23 cases (12 adult and 11 pediatric patients) of occipital bone defects in NF1 patients were selected. All patients had a single/multiple bone defect over the lambdoid suture. Adjacent benign plexiform neurofibromas were observed in 14 patients (60.8%, 7 adults and 7 children); one adult patient was diagnosed with neurofibrosarcoma. Meningoencephalocele over the occipital defect was noted in 8 cases (34.78%, all adults). Cranioplasty was performed in only 17.39% of patients. Histologic examination was performed in 7 of the 15 patients with associated neurofibromas/neurofibrosarcomas. Biopsy of the bone margins surrounding the defect was performed in only one case. Pathologic examination of the herniated parieto-occipital or cerebellar tissue was not performed in any of the patients studied. We report the case of a 9-year-old girl with NF1 and a significant occipital bone defect and performed a systematic review of the relevant literature to highlight the challenges in treating this condition and to investigate the underlying mechanisms contributing to bone defects or dysplasia in NF1.
Topics: Adult; Female; Humans; Child; Neurofibromatosis 1; Cafe-au-Lait Spots; Mutation; Encephalocele; Occipital Bone
PubMed: 37993698
DOI: 10.1007/s00381-023-06232-4 -
Neurosurgery Oct 2023Chiari I malformation (CIM) is characterized by descent of the cerebellar tonsils through the foramen magnum, potentially causing symptoms from compression or...
BACKGROUND
Chiari I malformation (CIM) is characterized by descent of the cerebellar tonsils through the foramen magnum, potentially causing symptoms from compression or obstruction of the flow of cerebrospinal fluid. Diagnosis and treatment of CIM is varied, and guidelines produced through systematic review may be helpful for clinicians.
OBJECTIVE
To perform a systematic review of the medical literature to answer specific questions on the diagnosis and treatment of CIM.
METHODS
PubMed and Embase were queried between 1946 and January 23, 2021, using the search strategies provided in Appendix I of the full guidelines.
RESULTS
The literature search yielded 430 abstracts, of which 79 were selected for full-text review, 44 were then rejected for not meeting the inclusion criteria or for being off-topic, and 35 were included in this systematic review.
CONCLUSION
Four Grade C recommendations were made based on Class III evidence, and 1 question had insufficient evidence. The full guidelines can be seen online at https://www.cns.org/guidelines/browse-guidelines-detail/2-symptoms .
Topics: Humans; Neurosurgeons; Arnold-Chiari Malformation; Patients; Evidence Gaps; Foramen Magnum
PubMed: 37646519
DOI: 10.1227/neu.0000000000002634 -
Neurosurgery Oct 2023Chiari I malformation (CIM) is characterized by descent of the cerebellar tonsils through the foramen magnum, potentially causing symptoms from compression or...
BACKGROUND
Chiari I malformation (CIM) is characterized by descent of the cerebellar tonsils through the foramen magnum, potentially causing symptoms from compression or obstruction of the flow of cerebrospinal fluid. Diagnosis and treatment of CIM is varied, and guidelines produced through systematic review may be helpful for clinicians.
OBJECTIVE
To perform a systematic review of the medical literature to answer specific questions on the diagnosis and treatment of CIM.
METHODS
PubMed and Embase were queried between 1946 and January 23, 2021, using the search strategies provided in Appendix I of the full guidelines.
RESULTS
The literature search yielded 567 abstracts, of which 151 were selected for full-text review, 109 were then rejected for not meeting the inclusion criteria or for being off-topic, and 42 were included in this systematic review.
CONCLUSION
Three Grade C recommendations were made based on Level III evidence. The full guidelines can be seen online at https://www.cns.org/guidelines/browse-guidelines-detail/1-imaging .
Topics: Humans; Neurosurgeons; Arnold-Chiari Malformation; Patients; Foramen Magnum
PubMed: 37646512
DOI: 10.1227/neu.0000000000002633 -
Forensic Science, Medicine, and... Mar 2024The objective of this study is to determine whether the morphometric evaluation of the foramen magnum using computed tomography can be used as an accurate tool in... (Meta-Analysis)
Meta-Analysis Review
The objective of this study is to determine whether the morphometric evaluation of the foramen magnum using computed tomography can be used as an accurate tool in estimating the sex of an individual. An extensive search of the databases, PubMed, ProQuest, Google Scholar, and Scopus, was carried out to procure articles that fulfilled the inclusion criteria. The AQUA tool was used to assess the quality of the included studies. A random effects model was used for the meta-analysis of the eligible studies using the STATA software, version 16, 2019 at 95% CI and p ≤ 0.05. Eleven eligible articles that measured the transverse and sagittal diameters of the foramen magnum using computed tomography were included in this study. The sagittal diameter of the foramen magnum was greater than the transverse diameter, and both the diameters were greater in males than in females. Meta-analysis revealed that both transverse and sagittal diameters were more reliable for male sex estimation. Since there is a dimensional variation between the male and female foramen magnum, it can be used for initial sex identification and also as an auxiliary to other advanced methods of sex estimation.
Topics: Humans; Male; Female; Foramen Magnum; Sex Determination by Skeleton; Tomography, X-Ray Computed
PubMed: 36971895
DOI: 10.1007/s12024-023-00613-6