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Moser M, Adl Amini D, Okano I, Oezel L, Shue J, Carrino JA, Sama AA, Cammisa FP, Girardi FP, Hughes AP. Trabecular volumetric bone mineral density of the occipital bone at preferred screw placement sites measured by quantitative computed tomography. J Orthop Res 2022; 40:1909-1917. [PMID: 34862648 DOI: 10.1002/jor.25224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/13/2021] [Accepted: 11/20/2021] [Indexed: 02/04/2023]
Abstract
This study aimed at quantifying trabecular volumetric bone mineral density (vBMD) at the external occipital protuberance (EOP) and the upper cervical spine. A retrospective review of patients who underwent non-contrast enhanced computed tomography of the cervical spine that included the occipital bone up to the EOP between 2007 and 2020 was conducted. Measurements of trabecular vBMD were performed in the occipital midline area, with the region of interest extending 4.5 mm above and below the center of the EOP, as well as the C1 lateral masses and the C2 vertebral body using asynchronous quantitative computed tomography. Eighty-six patients (female, 37.2%) were included for analysis. The patient population was 81.4% Caucasian with a mean ± SD age of 62.3 ± 13.1 years. Total bone thickness at the EOP was 16.7 ± 3.4 mm, with a ratio of trabecular to total bone thickness of 0.44. Trabecular vBMD (mean ± SD) was significantly higher at the EOP than at C1 and C2 (EOP = 612.3 ± 145.8 mg/cm3 , C1 average = 290.3 ± 66.5 mg/cm3 , C2 = 305.8 ± 78.8 mg/cm3 ; p < 0.001). A significant strong correlation between trabecular vBMD of C1 and C2 was observed (r = 0.744; p < 0.001), but only low correlations between the EOP and C1 (r = 0.295; p = 0.008) and C2 (r = 0.413; p < 0.001). In individuals > 65 years of age, cervical vBMD was significantly lower, but remained high at the EOP. Clinical significance: Trabecular vBMD at the EOP is significantly higher than at the upper cervical vertebrae and remains high in older populations. Together with morphological information about the occipital bone, these results might be helpful for occipitocervical fixation when deciding about uni- or bicortical screw placement at the EOP.
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Affiliation(s)
- Manuel Moser
- Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA
| | - Dominik Adl Amini
- Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA.,Department of Orthopaedic Surgery and Traumatology, Charité University Hospital Berlin, Berlin, Germany
| | - Ichiro Okano
- Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA.,Department of Orthopedic Surgery, Showa University School of Medicine, Tokyo, Japan
| | - Lisa Oezel
- Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA.,Department of Orthopaedic Surgery and Traumatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Jennifer Shue
- Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA
| | - John A Carrino
- Department of Radiology and Imaging, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA
| | - Andrew A Sama
- Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA
| | - Frank P Cammisa
- Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA
| | - Federico P Girardi
- Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA
| | - Alexander P Hughes
- Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medicine, New York, New York, USA
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Correlation of the external occipital protuberance with venous sinuses: a magnetic resonance imaging study. Surg Radiol Anat 2022; 44:999-1006. [PMID: 35737086 DOI: 10.1007/s00276-022-02969-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/03/2022] [Indexed: 10/17/2022]
Abstract
PURPOSE To date, no study has explored the external occipital protuberance (EOP) using neuroimaging modalities. This study aims to characterize them using magnetic resonance imaging (MRI). METHODS A total of 96 patients underwent thin-sliced, post-contrast MRI. The sagittal images were analyzed. RESULTS In 97%, the EOPs were delineated as a focal external protrusion of the midline region of the occiput with varying morphologies. In 89% of 93 patients with identifiable EOPs, parts of the intracranial dural sinuses were found to lie just below the inion, the most prominent point of the EOP. The most frequently targeted dural sinus was the confluence of sinuses that was found in 57%, followed by the superior sagittal sinus. In 16%, a bony foramen and transmitting vessel were detected in the EOP, connecting between the diploic channels and the subcutaneous veins. Furthermore, in 33%, bony foramina and transmitting venous structures were identified in the region just below the EOPs, connecting between the diploic channels and the subcutaneous veins. CONCLUSIONS The intracranial dural venous sinus is located just below the EOP with a high probability. Most bony foramina in the EOP and midline suboccipital region may transmit veinous structures connecting to the diploic channel.
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