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Liu H, Zhou ZY, Wei JX, Zhang M, Bai M, Huang AB. Comprehensive analysis of pedicle screw implantation in the C7 vertebra using computed tomography-based three-dimensional models. BMC Surg 2022; 22:96. [PMID: 35287657 PMCID: PMC8922919 DOI: 10.1186/s12893-022-01548-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 03/07/2022] [Indexed: 11/10/2022] Open
Abstract
Background From a biomechanical point of view, pedicle screws (PS) are better than other kinds of screws for implantation in the seventh cervical vertebra (C7). However, the application of PS is limited because of the high risk of severe complications. It is essential to define the optimal entry point and trajectory. The aim of this study was to comprehensively analyze the starting point and trajectory for C7 PS insertion using three dimensional (3D) models. Methods Overall, 60 subjects aged 18 to 67 years old were included. All CT images were used to construct 3D computer models of the C7 vertebrae. A new coordinate system was established for the next evaluation. The pedicle axis was calculated with respect to the entire pedicle; then, the ideal entry point, screw diameter and length, sagittal angle and lateral angle were assessed. Results All the ideal entry points were located at the medial superior to lateral notch (LN), and the mean distance between the entry point and LN was 5.86 ± 1.67 mm in the horizontal direction and 3.47 ± 1.57 mm in the vertical direction. The mean distance between the entry point and the middle point of the inferior edge of the C6 articular process (MP) was 0.74 ± 1.83 mm in the horizontal direction. The mean sagittal angle of the pedicle axis was 90.42°, and the mean pedicle transverse angle was 30.70°. The average diameter and length of the PS were 6.51 ± 0.76 mm and 31.58 ± 4.40 mm, respectively. Conclusions This study provided a novel method to calculate the ideal starting point and trajectory for C7 PS insertion. These measurements may be helpful for preoperative planning. It is recommended that 3D CT imaging is used preoperatively to carefully evaluate the anatomy of each individual.
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Affiliation(s)
- Huan Liu
- Postgraduate School, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Zhi-Yong Zhou
- Postgraduate School, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Jia-Xu Wei
- Postgraduate School, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Ming Zhang
- Postgraduate School, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Meng Bai
- Postgraduate School, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Ai-Bing Huang
- Department of Orthopedics, Hospital Affiliated 5 to Nantong University (Taizhou People's Hospital), Taizhou, 225300, Jiangsu, China. .,Postgraduate School, Dalian Medical University, Dalian, 116000, Liaoning, China.
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Pedicle Morphometry of Subaxial Cervical Spine Using Computed Tomography Scans among Adult Ugandan Subpopulation. Int J Biomed Imaging 2022; 2022:6351465. [PMID: 35283992 PMCID: PMC8904905 DOI: 10.1155/2022/6351465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 02/03/2022] [Accepted: 02/10/2022] [Indexed: 11/21/2022] Open
Abstract
Background Accurate placement of pedicle screws in the subaxial cervical spine requires precise understanding of vertebra anatomy. Little is known about the morphometric characteristics of the subaxial cervical pedicle in the Ugandan population. The objective of the study was to determine the morphometric dimensions of pedicles in the subaxial cervical spine among the adult Ugandan population. Methods We conducted a cross-sectional study from March to November 2019 among adult Ugandans with a normal cervical CT scan at Nsambya hospital in Kampala. Eligible participants were consecutively recruited into the study. Data on baseline characteristics and pedicle dimensions from the CT scan finding was collected using a structured questionnaire. Data was analysed using Stata 13.0. Pedicle dimensions for the different levels of subaxial cervical vertebrae were summarised as means and standard deviations, the Mann–Whitney test was used to compare pedicle dimensions for the different vertebra levels among females and males on both right and left sides, and the level of significance was set at 0.05. Results A total of 700 subaxial cervical pedicles (C3-C7) from 49 males and 21 female participants were studied. Pedicle width diameter showed cephalocaudal gradual increment from C3 1.65(0.63) mm to 3.46(0.75) mm at C7. Pedicle height also showed an increase caudally with smallest diameter at C3 (1.98(0.76) mm) and largest at C5 in females (3.67(6.42) mm) and at C7 in males (3.83(0.76) mm). The pedicle height was wider than the pedicle width at all levels. The pedicle chord length gradually increased caudally in both sexes ranging from 29.08(1.35) mm at C3 to 32.53(3.19) mm at C7. The axial angles were oriented medially and showed no consistent trend ranging between 50° and 53°. The sagittal angles decreased as one moved from C3 to C7. The dimensions of females were significantly smaller than in males. Conclusion Pedicle endosteal width was smaller than pedicle height dimensions at all levels. Pedicle cord length increased caudally. The pedicle dimensions, except angulations, were smaller in females than in males.
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Martin-Schutz GO, Amaral CAB, Labronici PJ, Pires LAS. MORPHOMETRIC STUDY OF THE C6 AND C7 PEDICLE: A COMPUTERIZED TOMOGRAPHY ANALYSIS. COLUNA/COLUMNA 2022. [DOI: 10.1590/s1808-185120222104262589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
ABSTRACT Objective: Measure the diameter and thickness of the C6 and C7 pedicles using computed tomography, to analyze the security of the act surgery and the difference between males and females. Methods: This is a retrospective study. Two hundred computerized tomography scans of the cervical spine, one hundred male and one hundred female, from the Hospital Santa Teresa Radiology sector were evaluated. The pedicle thickness was measured in the axial plane, and the height was measured in sagittal slices. The student’s t-test was used to compare differences between the sexes, and a p-value lower than 0.05 was considered significant. Results: The mean age of the individuals included in the sample was 35±9 years. The mean height of the C6 and C7 pedicles were 7.1±0.9 mm and 7.8±0.9 mm, respectively. The mean thickness of the C6 and C7 pedicles were 5.2±0.7 mm and 5.9±0.8 mm, respectively. The statistical test showed that the values were significantly lower for female patients. Conclusions: The present study demonstrated parameters that can be used and can be the rule for preoperative planning of transpedicular cervical fixation surgeries, both in C6 and C7. As it is a procedure that can cause iatrogenic damage to important structures, the screw size must be chosen with care in pre-operative planning to avoid vessel rupture or damage to adjacent nerves. Level of Evidence III; retrospective study.
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Alsaleh K, Essbaiheen F, Aldosari K, Alsubei B, Alabdulkareeem M. Morphometric Analysis of Subaxial Cervical Spine Pedicles in a Middle Eastern Population. Int J Spine Surg 2021; 15:413-417. [PMID: 33963031 DOI: 10.14444/8061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Pedicle screw instrumentation of the posterior cervical spine is the most secure form of fixation available to surgeons. It has not achieved widespread use yet in the Middle East, mostly due to concerns regarding its feasibility in the target population. A detailed morphometric analysis of the lower cervical spine pedicles using computerized tomography (CT) was proposed to address this issue. METHODS Two hundred and seventy patients were enrolled in the study. CT scans were reviewed by two experienced assessors, and measurements of pedicle width (PW), height (PH), and transverse angle (TA) were recorded for all patients. Interobserver and intraobserver reliability were calculated using the kappa statistic. Sex differences were also recorded and analyzed. The t test was used to assess for any significant differences in measurements due to sex (P < .05). RESULTS The mean PW varied from 4.4 mm in C3 to 6.1 mm in C7. The mean PH was 6.4 mm in C3 and 6.8 mm in C7. Pedicle TA varied from 42 to 51 degrees between the different levels. Sex differences were observed and were statistically significant for PW and PH. Interobserver reliability was high for PW and PH, but was low for TA. Intraobserver reliability was 0.99 for both assessors. CONCLUSION This study provides reliable PW and PH measurements and demonstrates that cervical pedicle screw instrumentation is feasible in our local population. Significant variability exists, however, and each patient must be addressed individually for best results. LEVEL OF EVIDENCE 3. CLINICAL RELEVANCE This study shows that the morphology of the subaxial cervical pedicle permits instrumentation in a majority of cases of our target population.
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Affiliation(s)
- Khalid Alsaleh
- Department or Orthopedics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Fahad Essbaiheen
- Department of Radiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | | | - Bandar Alsubei
- Department or Orthopedics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
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Kumar S, Saini NK, Singh D, Chadha M, Mehrotra G. Computed tomographic analysis of cervical spine pedicles in the adult Indian population. Surg Neurol Int 2021; 12:68. [PMID: 33767872 PMCID: PMC7982095 DOI: 10.25259/sni_926_2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/02/2021] [Indexed: 11/25/2022] Open
Abstract
Background: Cervical pedicle screw insertion is a technically demanding procedure that carries the risk of catastrophic damage to surrounding neurovascular structures. Here, we analyzed computed tomography (CT)-based three-dimensional cervical spine pedicle geometry to determine the level and sex-specific morphologic differences in the adult Indian population. Methods: The CT scans of 200 patients (2400 pedicles) without significant cervical spine pathology were collected. The mean pedicle width (PW), pedicle height (PH), pedicle axial length (PAL), and pedicle transverse angle (PTA) from C2 to C7 were measured. Results: The smallest mean PW was at C3 in both males (4.85 ± 0.73 mm) and females (4.31 ± 0.43 mm); 7.08% of all pedicles were found to have mean PW of <4 mm. The smallest mean PH was at C5 in both males (6.25 ± 0.67mm) and females (5.54 ± 0.52 mm). The smallest mean PAL was at C2 in both males (27.46 ± 1.69mm) and females (25.90 ± 1.88 mm). The mean PW, PH, and PAL were significantly greater in males than females at all levels (P < 0.05). The smallest mean PTA was at C3 in males (41.79 ± 2.53°) and at C7 in females (42.40 ± 2.27°). Conclusion: In the adult Indian population, the PW, PH and PAL were smaller than in the typical western population. Females had even smaller PW, PH and PAL as compared to males. We recommend that a small inventory of 3.5mm screws between 20mm to 30mm length be used in most cases where cervical pedicle screws are being used in the Indian population. However, individual vertebrae should be screened preoperatively with CT scans to exclude gross anatomical variations, especially in females and at the C3 and C4 levels.
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Affiliation(s)
- Sanjeev Kumar
- Department of Orthopedics, Guru Teg Bahadur Hospital, University College of Medical Sciences, New Delhi, India
| | - Naresh Kumar Saini
- Department of Orthopedics, Guru Teg Bahadur Hospital, University College of Medical Sciences, New Delhi, India
| | - Devender Singh
- Department of Orthopedics, Dr Ram Manohar Lohia Hospital, University College of Medical Sciences, New Delhi, India
| | - Manish Chadha
- Department of Orthopedics, Guru Teg Bahadur Hospital, University College of Medical Sciences, New Delhi, India
| | - Gopesh Mehrotra
- Department of Radiology, Guru Teg Bahadur Hospital, University College of Medical Sciences, New Delhi, India
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Toki S, Higashino K, Manabe H, Morimoto M, Sugiura K, Tezuka F, Yamashita K, Takata Y, Maeda T, Sakai T, Yasui N, Sairyo K. Morphometric Analysis of Subaxial Cervical Spine with Myelopathy: A Comparison with the Normal Population. Spine Surg Relat Res 2021; 5:34-40. [PMID: 33575493 PMCID: PMC7870320 DOI: 10.22603/ssrr.2020-0061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 06/02/2020] [Indexed: 11/24/2022] Open
Abstract
Introduction The specific morphology and differences between patients with cervical spondylotic myelopathy (CSM) and those with normal spines remain unclear. This study aimed to evaluate and determine the features of cervical spine morphology on reconstructive CT. Methods We investigated that axial reconstructive CT scans of the cervical spine at C3 to C7 were obtained from 309 individuals (97 CSM patients and 212 controls). Those of the optimal pedicle diameter were selected, and the following parameters were measured: (a) sagittal diameter of the spinal canal (b) transverse diameter of the spinal canal, (c) pedicle width, (d) lateral mass thickness, (e) transverse diameter of the foramen, (f) sagittal diameter of the vertebral body, and (g) transverse diameter of the vertebral body. The following ratios were calculated using these values: the sagittal-transverse ratio and the canal-body ratio. Results Most parameters differed significantly between the sexes in both groups. The parameters without the mean sagittal diameter of the spinal canal were significantly larger in men than in women. However, the mean sagittal diameter of the spinal canal did not differ significantly between the sexes in CSM patients. The sagittal-transverse ratio and canal-body ratio were significantly smaller in the CSM patients at all levels. According to relative operating characteristic curves of the sagittal diameter of the spinal canal, sagittal-transverse ratio, and canal-body ratio, the sensitivity from C3 to C7 in both sexes was > 60% at the threshold. In men, the specificity from C3 to C7 was also >60% at the threshold. Conclusions The morphometry of the sagittal diameter of the spinal canal, sagittal-transverse ratio, and canal-body ratio on axial reconstructive CT images appears useful for distinguishing cervical spinal canal stenosis involving myelopathy.
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Affiliation(s)
- Shunichi Toki
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Kosaku Higashino
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Hiroaki Manabe
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Masatoshi Morimoto
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Kosuke Sugiura
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Fumitake Tezuka
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Kazuta Yamashita
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Yoichiro Takata
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Toru Maeda
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Toshinori Sakai
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Natsuo Yasui
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Koichi Sairyo
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
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Abstract
STUDY DESIGN This study investigated the subaxial cervical pedicles from C3 to C7 to provide information for accurately transpedicular screw fixation in this region. OBJECTIVE This study was evaluated the morphology of the subaxial cervical pedicle to determine the size and trajectory of screw fixation. SUMMARY OF BACKGROUND DATA Cervical vertebrae are an important structure to protect the neurovascular structure. The cervical spine surgery using screw fixation is an effective method to treat the cervical spine instability. There have been many research morphological data of subaxial cervical vertebrae. However, no studies have reports on dried cervical vertebrae of Thai's people. METHODS The measurement was conducted in 130 dried cervical vertebrae (C3-C7), including 61 males and 69 females. The measurement parameters were pedicle width (PW), pedicle length (PL), pedicle height (PH), pedicle axis length (PAL), pedicle transverse angle (PTA), and pedicle sagittal angle (PSA), which determined using ImageJ software. RESULTS The results of morphological data of C3 to C7 was found that the mean of PW, PL, PH, PAL, PTA, and PSA that obtained from male were significantly higher than female excepted for PL (C7) and PTA (C3, C5). Except for the C6 PW, C3 PL, C4 to C5 to C7 PTA, and C4 PSA, there were no significant differences of these parameters between male and female. CONCLUSION The appropriate pedicle screw size is 4.0 mm for C3 and C4, and 4.5 mm for C5 to C7. The results of this study are the useful information for cervical spine fixation while prevent the vascular and neurological injuries from the large screw causing pedicle breakage. LEVEL OF EVIDENCE 3.
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Moser M, Farshad M, Farshad-Amacker NA, Betz M, Spirig JM. Accuracy of Patient-Specific Template-Guided Versus Freehand Cervical Pedicle Screw Placement from C2 to C7: A Randomized Cadaveric Study. World Neurosurg 2019; 126:e803-e813. [PMID: 30862583 DOI: 10.1016/j.wneu.2019.02.152] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND Dorsal spinal instrumentation with cervical pedicle screws (CPS) and rod constructs is performed for numerous pathologies of the cervical spine, although technically demanding. Screw misplacement is biomechanically disadvantageous and carries the risk of neurovascular sequelae. The aim of this study was to assess the accuracy of patient-specific, template-guided CPS placement from C2 to C7 compared with the freehand technique. METHODS Patient-specific targeting guides were used for placement of 3.5 mm CPS from C2 to C7 in 4 cadaveric specimens. Template-guided instrumentation was randomized for each cervical level and side and the contralateral side instrumented likewise but with the freehand technique. No fluoroscopy was used at all, and the spinal canal was not opened for the freehand technique. Accuracy was assessed by computed tomography, grading perforations using a 2-mm increment method, and time efficiency was compared between the 2 techniques. RESULTS In total, 48 screws were inserted with an equal distribution of 24 screws (50%) in each of the 2 groups. Outer pedicle width averaged 5.1 ± 1.0 mm (range 2.7-7.8); 66.7% (n = 16) of template-guided versus 20.8% (n = 5) of freehand CPS were fully contained within the pedicle (P = 0.001), whereas 91.7% (n = 22) versus 50% (n = 12) were within the <2 mm "safe" zone (P = 0.001). The mean time for instrumentation per level and side was 03:09 ± 01:37 minutes for the template-guided versus 02:32 ± 01:04 minutes for the freehand technique (P = 0.132). CONCLUSIONS In a cadaver model, template-guided CPS placement has a significantly greater accuracy than the freehand technique. This accuracy is comparable with navigated techniques reported in the literature.
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Affiliation(s)
- Manuel Moser
- Spine Division, Department of Orthopedics, Balgrist University Hospital Zurich, Zurich, Switzerland; Department of Spine Surgery, Cantonal Hospital of Lucerne, Lucerne, Switzerland.
| | - Mazda Farshad
- Spine Division, Department of Orthopedics, Balgrist University Hospital Zurich, Zurich, Switzerland
| | | | - Michael Betz
- Spine Division, Department of Orthopedics, Balgrist University Hospital Zurich, Zurich, Switzerland
| | - José Miguel Spirig
- Spine Division, Department of Orthopedics, Balgrist University Hospital Zurich, Zurich, Switzerland
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Pan Z, Zhong J, Xie S, Yu L, Wu C, Ha Y, Kim KN, Zhang Y, Cao K. Accuracy and Safety of Lateral Vertebral Notch-Referred Technique Used in Subaxial Cervical Pedicle Screw Placement. Oper Neurosurg (Hagerstown) 2018; 17:52-60. [DOI: 10.1093/ons/opy233] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 07/27/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Zhimin Pan
- Department of Orthopaedics, the Second Affiliated Hospital of Nanchang University, Nanchang, China
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Junlong Zhong
- Department of Orthopaedics, the Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Shiming Xie
- Department of Orthopaedics, Mianyang Orthopaedic Hospital, Mianyang, China
| | - Limin Yu
- Department of Spine Surgery, Peking University Shenzhen Hospital, Shenzhen, China
| | - Chunyang Wu
- Department of Orthopaedics, the Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Yoon Ha
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Keung Nyun Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Youshan Zhang
- Computer of Science Engineering, Lehigh University, Bethlehem, Pennsylvania
| | - Kai Cao
- Department of Orthopaedics, the Second Affiliated Hospital of Nanchang University, Nanchang, China
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Oshina M, Oshima Y, Matsubayashi Y, Taniguchi Y, Chikuda H, Riew KD, Tanaka S. Nutrient foramen location on the laminae provides a landmark for pedicle screw entry: a cadaveric study. BMC Musculoskelet Disord 2018; 19:293. [PMID: 30115052 PMCID: PMC6097445 DOI: 10.1186/s12891-018-2218-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/01/2018] [Indexed: 11/22/2022] Open
Abstract
Background Nutrient foramina are often encountered around the entry point of pedicle screws. Further, while probing the pedicle for pedicle screw insertion around the nutrient foramen, bleeding from the probe insertion hole is often observed. The purpose of this study was to investigate the frequency of occurrence of nutrient foramina, the association between the nutrient foramen and pedicle, and the safety and accuracy of cervical and thoracic pedicle screw placement using the nutrient foramen as the entry point. Methods We identified the location of the nutrient foramina for the dorsal branches of the segmental artery and their anatomical association to the pedicles and bony landmarks in the vertebrae for C3–T12 in seven cadavers. We also determined the frequency with which the nutrient foramina were present in 119 cadaveric vertebrae. We identified the pedicle location, base of the superior articular facet, and lateral border of laminae with respect to the nutrient foramen. Results The overall presence of the nutrient foramina was 63% (150/238) in the specimens, with 60% (42/70) and 64% (108/168) identifiable in the cervical and thoracic vertebrae, respectively. In the cervical vertebrae, the nutrient foramen was located on the outer wall of the pedicle and was positioned between the cephalad and caudal walls. In the thoracic spine, 98% (106/108) nutrient foramina were located inside the pedicle walls. Conclusions Our study findings confirm that the location of the nutrient foramen can be used for identifying the entry point for pedicle screws. In the cervical vertebrae, the nutrient foramina are located lateral to pedicle but within the cranial and caudal margins. In the thoracic vertebrae, the nutrient foramina are located in the medial and caudal regions of the pedicle. Thus, to decrease the risk of overshoot, the entry point for thoracic pedicle screws should be positioned a few millimeters cephalad and lateral to the nutrient foramen.
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Affiliation(s)
- Masahito Oshina
- Department of Orthopaedic Surgery, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
| | - Yasushi Oshima
- Department of Orthopaedic Surgery, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan
| | - Yoshitaka Matsubayashi
- Department of Orthopaedic Surgery, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan
| | - Yuki Taniguchi
- Department of Orthopaedic Surgery, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan
| | - Hirotaka Chikuda
- Department of Orthopaedic Surgery, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan
| | | | - Sakae Tanaka
- Department of Orthopaedic Surgery, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan
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Farooque K, Yadav R, Chowdhury B, Gamanagatti S, Kumar A, Meena PK. Computerized Tomography-Based Morphometric Analysis of Subaxial Cervical Spine Pedicle in Asymptomatic Indian Population. Int J Spine Surg 2018; 12:112-120. [PMID: 30276069 DOI: 10.14444/5017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background The purpose of this study was to analyze morphometry of the subaxial cervical spine pedicles in an Indian population based on computed tomography (CT), and thus assess the safety and feasibility of cervical pedicle screw in the subaxial cervical spine. Methods CT scans of 500 subaxial cervical spine vertebrae were analyzed from 100 patients presenting to our institution and undergoing cervical spine CT scan for an unrelated cause as part of ATLS protocol. Pedicle width (PW), pedicle axis length (PAL), pedicle transverse angulation (PTA), and lateral pedicle distance (LPD) were calculated on axial CT scans, and pedicle height (PH), pedicle length (PL), superior pedicle distance (SPD), and pedicle sagittal angulation (PSA) were calculated on sagittal CT scans. Results The mean PW ranged from 4.3 mm at C3 to 5.7 mm at C7. Mean PH ranged from 5.5 mm at C3 to 6.1 mm at C7. Mean PTA ranged from 44.5° at C3 to 37.1° at C7. PSA ranged from 16.65° at C3 to 3.29° at C7. Mean LPD ranged from 1.6 mm at C3 to 3.4 mm at C6. Mean SPD ranged from 3.5 mm at C3 to 1.15 mm at C7. Mean PAL ranged from 29.6 mm at C3 to 33.04 mm at C7. Mean PL ranged from 5.2 mm at C3 to 5.78 mm at C7. Conclusions Our CT-based morphometric study confirms that cervical pedicle screw placement is possible in most of the Indian population except at C3 in females. A thorough understanding of pedicle anatomy with proper CT-based preoperative planning can mitigate the risk associated with pedicle screw placement in subaxial cervical spine.
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Affiliation(s)
- Kamran Farooque
- Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India
| | - Rahul Yadav
- Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India
| | - Buddhadev Chowdhury
- Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India
| | - Shivanand Gamanagatti
- Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India
| | - Atin Kumar
- Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India
| | - Pradeep Kumar Meena
- Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India
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Westermann L, Spemes C, Eysel P, Simons M, Scheyerer MJ, Siewe J, Baschera D. Computer tomography-based morphometric analysis of the cervical spine pedicles C3-C7. Acta Neurochir (Wien) 2018; 160:863-871. [PMID: 29411117 DOI: 10.1007/s00701-018-3481-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 01/25/2018] [Indexed: 10/18/2022]
Abstract
BACKGROUND Our aim was to examine the specific dimensions of cervical pedicles in a large Caucasian cohort on high dissolving CT scans. METHODS A retrospective analysis of 100 cervical spine CT scans with a maximum slice thickness of 1 mm in axial, sagittal, and coronal reconstructions was performed. The pedicle axial length (PAL), inner and outer pedicle diameter (IPD/OPD), pedicle sagittal and transverse angle (PSA/PTA), pedicle height (PH), pedicle width (PW), and the cortical thickness (COT) at different margins were measured by two independent observers. A total of 1000 cervical pedicles (C3-C7) of 52 male (age 58 ± 17.47 years, height 177.97 ± 8.17 cm) and 48 female patients (age 57 ± 19.07 years, height 165.50 ± 7.44) were measured. RESULTS Cortical thickness at the medial limitation of the pedicle was 1.77 ± 0.43 and 0.90 ± 0.36 mm at the lateral limitation (p < 0.001). The mean PAL ranged from 30.5 mm at C4 level to 35.3 mm at C6 level. PW and PAL were smaller in the female than in the male patients. The smallest values for PW were at C3 with 29.17% of males and 52.88% of females < 4.5 mm. The percentage of patients with PW < 4.5 mm decreased caudally with less than 10% of pedicles below C4 in male participants and below C6 in female participants. Mean PTA ranged from 34.6° to 48.02° peaking at C4 and C5 levels. No gender-specific difference was found for PTA and PSA (p ≥ 0.13). IPD and OPD were larger in males (p < 0.001), and body height correlated significantly with IPW (p ≤ 0.019) and OPW (p ≤ 0.003). The interrater reliability was very good for PW, PH, and IPD (0.84-0.86), good for OPD, PTA, and PSA (0.64-0.79), and moderate for PAL (0.54) and cortical thickness (0.44). CONCLUSIONS Peculiarities of pedicle dimension of this central European cohort are comparable to morphometric studies in other ethnicities. Preoperative planning before cervical pedicle screw insertion on fine-cut CT scans demonstrates good interrater reliability for all important dimensions and angulations. More than half of female patients and almost a third of male patients had a PW of less than 4.5 mm at C3 level. Even though this percentage decreases caudally, pedicle screws might not be safe to insert in a noteworthy percentage of patients.
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Chen W, Fang XM, Qian PY, Sanjeev Kumar PS, Chen HW, Xiao-Yun HU. Evaluation of Multi-Slice Spiral Computed Tomography in In vivo Simulation of Individualized Cervical Pedicle Screw Placement at C3-C7 in Chinese Healthy Population. Indian J Orthop 2018; 52:651-656. [PMID: 30532307 PMCID: PMC6241050 DOI: 10.4103/ortho.ijortho_3_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Cervical pedicle screw fixation through posterior approach has shown greater cervical stability advantage. The cervical pedicle screw fixation technique through posterior approach is demanding. The key to the technique is the choice of point and angle of screw entrance. The angle of screw placement is variable. Morphometric measurements of the cervical pedicle are a prerequisite for individualized screw. CT imaging has become the most reliable and important means to obtain cervical pedicle's measurement data and morphology in vivo. This study explores the feasibility and application of precise in vivo measurements by multi-slice computed tomography (MSCT) for individualized cervical transpedicular screw placement at C3-C7 in Chinese healthy population. MATERIALS AND METHODS 80 adults who underwent cervical examination by enhanced and nonenhanced computed tomography angiography, respectively, were selected and submitted to bone algorithm reconstruction for slice thickness and interval of 0.75 mm to acquire clear images and detailed bone structures. Simulation of individualized screw placement was performed with a 4.0 mm diameter screw with the help of postprocessing workstation. Pedicle transverse angle (PTA) and sagittal angle (PSA) were measured using the single- and double-line methods (analog nailing, 4.0 mm in diameter) in 160 pairs of C3-C7 pedicles, setting positive and negative values for cranial direction and foot side PSAs, respectively. Comparison of the measured change scope in PTA and PSA between the two methods was carried out; the range was defined as the error range. RESULTS Significantly, different results (P < 0.05) were obtained between the single- and double-line methods in the error ranges of PTA and PSA in C3-C7 pedicles. Interestingly, the double-line method was better in simulating the actual needs of individualized nailing. The mean values of PTA and PSA were 42.9°, 45.5°, 42.4°, 37.1°, 29.0° and 8.4°, 5.0°, -4.0°, and -7.8°, -8.1°, respectively, with the double-line method. CONCLUSION MSCT reconstruction techniques can determine the direction and required parameters for individualized screw placement. In addition, accurate in vivo measurements of PTA and PSA, particularly PSA, provide the orthopedic surgeon with theoretical guidance and reliable basis in screw placement.
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Affiliation(s)
- Wei Chen
- Department of Intervention Radiology, Huai’an First People's Hospital, Nanjing Medical University, Jiangsu Province, China
| | - Xiang-Ming Fang
- Imaging Center, Wuxi People's Hospital Affiliated to Nanjing Medical University, Jiangsu Province, China
| | - Ping-Yan Qian
- Imaging Center, Wuxi People's Hospital Affiliated to Nanjing Medical University, Jiangsu Province, China
| | - PS Sanjeev Kumar
- Department of Medical Imaging, Parexel International Pvt Ltd, Hyderabad, Telangana, India
| | - Hong-wei Chen
- Imaging Center, Wuxi People's Hospital Affiliated to Nanjing Medical University, Jiangsu Province, China
| | - HU Xiao-Yun
- Imaging Center, Wuxi People's Hospital Affiliated to Nanjing Medical University, Jiangsu Province, China,Address for correspondence: Dr. Xiao-Yun HU, Imaging Center, Wuxi People's Hospital Affiliated to Nanjing Medical University, No. 299, Qingyang Road, Wuxi 214023, Jiangsu Province, China. E-mail:
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Yao X, Liu S. In vitro study of accuracy of subaxial cervical pedicle screw insertion using calipers based on the gravity line. PLoS One 2017; 12:e0181324. [PMID: 28727778 PMCID: PMC5519080 DOI: 10.1371/journal.pone.0181324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 06/29/2017] [Indexed: 11/23/2022] Open
Abstract
Object There is a high probability of iatrogenic perforation of the vertebral pedicle wall during the application of subaxial cervical pedicle screw (CPS). The goal of this study was to evaluate the accuracy of CPS insertion at C3-C7 in vitro using novel calipers based on the gravity line. Methods Nine cadaveric cervical spines underwent computed tomography scanning and preoperative design. A lateral fluoroscopic view was taken to measure the intra-operative sagittal angle by C-arm with hanging cross structured K-wires. By referring to the gravity line, caliper A was used to locate the entry point, while caliper B was employed to guide the screw insertion. Postoperative CT scans were performed to assess the accuracy of the screw placements, according to the Neo classification. Results Overall, 78 (88.6%) of the 88 pedicle screw placements were classified as grade 0 (correct position), 4 (4.5%) were grade 1 (non-critical perforation), 4 (4.5%) were grade 2 (critical perforation), and 2 (2.3%) were grade 3 (critical perforation). Conclusions Using our novel calipers and referring to the gravity line was helpful for locating and guiding individual cervical pedicle screw insertions.
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Affiliation(s)
- Xiang Yao
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, PR China
| | - Shiqing Liu
- Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, PR China
- * E-mail:
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Wu C, Huang Z, Pan Z, Luo J, Li Z, Zhong J, Chen Y, Han Z, Abumi K, Ha Y, Cao K. Coronal Multiplane Reconstructed Computed Tomography Image Determining Lateral Vertebral Notch-Referred Pedicle Screw Entry Point in Subaxial Cervical Spine: A Preclinical Study. World Neurosurg 2017; 103:322-329. [PMID: 28434954 DOI: 10.1016/j.wneu.2017.04.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 04/05/2017] [Accepted: 04/07/2017] [Indexed: 10/19/2022]
Abstract
OBJECTIVE To evaluate feasibility of computed tomography (CT) coronal multiplane reconstruction image (CMRI) to determine subaxial cervical pedicle screw (PS) entry point and guide lateral vertebral notch (LVN)-referred technique for subaxial cervical PS insertion. METHODS Cervical CT scans were performed in 40 volunteers. PS entry point was determined by quantitating PS entry point related to LVN on CMRI. Pedicle mediolateral angle (α) and cephalocaudad angle (β) were also measured to guide the trajectory of PS insertion. Based on these quantitations, 12 human cadaveric subaxial cervical pedicles were inserted with PS referring to LVN. Cortical integrity of each pedicle was evaluated after dissecting the cadaveric vertebrae one by one and confirmed by radiography and CT. The cortical penetration and PS position were classified into 4 grades: 0 (excellent position), I (good position), II (fair position), and III (poor position). RESULTS On CT CMRI, PS entry point was consistently located approximately 2.2 mm medial to LVN from C3 to C7 and approximately 1.4 mm lower to LVN from C3 to C6, but 1.2 mm higher at C7. Bilateral α angle and β angle showed substantial decrease from cranial to caudal. Cortical integrity of PS positions was excellent and good in 88.33%, fair in 8.33%, and poor in 3.33%. CONCLUSIONS CMRI is reliable for determining subaxial cervical PS entry point. LVN is a consistent landmark for the notch-referred technique, which is a practical and easy to master technique for subaxial cervical spine PS insertion.
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Affiliation(s)
- Chunyang Wu
- Department of Orthopaedics, The First Affiliated Hospital of Nanchang University, Jiangxi, China
| | - Zhongren Huang
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Jiangxi, China
| | - Zhimin Pan
- Department of Orthopaedics, The First Affiliated Hospital of Nanchang University, Jiangxi, China; Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jiaquan Luo
- Department of Orthopaedics, The First Affiliated Hospital of Nanchang University, Jiangxi, China
| | - Zhiyun Li
- Department of Orthopaedics, The First Affiliated Hospital of Nanchang University, Jiangxi, China
| | - Junlong Zhong
- Department of Orthopaedics, The First Affiliated Hospital of Nanchang University, Jiangxi, China
| | - Yiwei Chen
- Department of Orthopaedics, The First Affiliated Hospital of Nanchang University, Jiangxi, China
| | - Zhimin Han
- Department of Orthopaedics, The First Affiliated Hospital of Nanchang University, Jiangxi, China
| | - Kuniyoshi Abumi
- Center for Spinal Disorders, Sapporo Orthopaedic Hospital, Sapporo, Japan
| | - Yoon Ha
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea.
| | - Kai Cao
- Department of Orthopaedics, The First Affiliated Hospital of Nanchang University, Jiangxi, China.
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LÁMBARRI JESÚSCISNEROS, LÓPEZ JOSÉTOVAR, TELLEZ JOSÉGRIMALDO, SANDOVAL HARO. USE OF CT FOR ANALYSIS OF THE VERTEBRAL FORAMEN IN THE HOSPITAL OF QUERÉTARO. COLUNA/COLUMNA 2017. [DOI: 10.1590/s1808-185120171602172271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ABSTRACT Objective: To determine the morphology of the vertebral foramen and its distance to the midline. Methods: Twenty cervical CT scans from the radiographic record of 12 men and 8 women, 18 to 74 years old, of C1 to C6 segments were evaluated, measuring the foramen diameter and its distance to the midline. We look for anomalies of vertebral foramen morphology, using Philips Ingenuity CT equipment with Philips IntelliSpace Portal software. Results: The mean age was 47 years; the segment with the most anomalies was C1, with 10% (increase in foramen diameter), followed by C2 and C6, with 5% (vertebral foramen hypotrophy); the mean diameter of the C1 to C6 segment was 6.081 mm, and the median distance from the midline to the vertebral foramen of C2 to C6 was 13.215 mm. The largest diameter of the vertebral foramen was C2, with a mean of 6.67 mm and the smallest was C4, with a mean of 5.75 mm; the greatest distance from the midline to the vertebral foramen was C1, with a mean of 22.59 mm and the shortest was C4, with a mean of 12.13 mm. Conclusions: The mean diameter of the vertebral foramen and its distance to the midline was determined, setting a safety region for procedures. In our city, there is no study that determines the means of the vertebral foramina diameters, the distance from the midline and its anomalies. It is necessary to rely on CT scans and to make a preoperative plan to avoid complications associated with morphological alterations.
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Novel Landmark for Cervical Pedicle Screw Insertion Point from Computed Tomography-Based Study. Asian Spine J 2017; 11:82-87. [PMID: 28243374 PMCID: PMC5326737 DOI: 10.4184/asj.2017.11.1.82] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/07/2016] [Accepted: 07/24/2016] [Indexed: 11/22/2022] Open
Abstract
Study Design Cross-sectional study. Purpose The purpose of this study was to evaluate a novel landmark for the cervical pedicle screw insertion point. Overview of Literature To improve the accuracy of pedicle screw placement, several studies have employed the lateral mass, lateral vertical notch, and/or inferior articular process as landmarks; however, we often encounter patients in whom we cannot identify accurate insertion points for pedicle screws using these landmarks because of degenerative changes in the facet joints. The superomedial edge of the lamina is less affected by degenerative changes, and we hypothesized that it could be a new landmark for identifying an accurate cervical pedicle screw insertion point. Methods A total of 327 consecutive patients, who had undergone neck computed tomographic scanning for determination of neck disease in our institute, were included in the study. At first, the line was drawn parallel to the superior border of the pedicle in the sagittal plane and parallel to the vertical body in the coronal plane. The line was moved downward in 1-mm increments to the inferior border of the pedicle. We determined whether the line passing through the superomedial edge of the lamina (termed the “N-line”) was located between the superior and inferior borders of the pedicle in the sagittal plane. Results The percentages of N-lines located between the superior and inferior borders of the pedicle were 100% at C3, 100% at C4, 99% at C5, 96% at C6, and 97% at C7. The lower cervical spine has the higher N-line location. Conclusions The N-line was frequently located at the level of the pedicle of each cervical spine in the sagittal plane. The superomedial edge of the lamina could be a new landmark for the insertion point of the cervical pedicle screw.
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Saluja S, Patil S, Vasudeva N. Morphometric Analysis of Sub-axial Cervical Vertebrae and Its Surgical Implications. J Clin Diagn Res 2015; 9:AC01-4. [PMID: 26673539 DOI: 10.7860/jcdr/2015/15053.6808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 08/19/2015] [Indexed: 11/24/2022]
Abstract
BACKGROUND The predilection of the cervical spine to a wide array of traumatic, degenerative and neoplastic diseases necessitates frequent surgical interventions. For successful surgical management of these conditions, a detailed anatomical knowledge of the cervical spine is required but variability in vertebral dimensions exists amongst different races and prevents the standardization of measurements. AIM The aim of this study was to present a morphometric reference database for cervical vertebrae of the Indian population and enable comparisons with other populations. MATERIALS AND METHODS The study was conducted on 203 typical (C3-C6) cervical vertebrae. Linear measurements of the vertebrae were taken with the help of digital Vernier caliper and angular measurements were determined with software Image J. STATISTICAL ANALYSIS Mean and standard deviation of the morphometric parameters taken into account were analysed. The comparison of morphometric dimensions of the right and left sides was performed using Student's t-test and p-value was calculated. RESULTS The morphometric analysis of the cervical vertebrae demonstrated that when compared with other races, the mean height (11.39 ± 1.08 mm) and transverse diameters (22.18 ± 2.52 mm) of the vertebral body were larger but antero-posterior diameter was less, making the vertebral bodies in Indians transversely longer. The dimensions of the pedicle, laminae, articular processes and spinous process were smaller when compared to other populations. There existed a highly significant difference (p=0.002) between the widths of the right and left superior & inferior articular processes. A great disparity of the pedicle transverse angle was noted in different populations but in Indians the angle was 44.47 ± 2.81. CONCLUSION The present morphometric study in Indian population would be valuable for the successful instrumentation of the cervical spine as smaller dimensions of the cervical vertebrae pose a challenge to the surgeons during application of plates and screws. The data would be helpful in designing spinal implants and permit identification of osteological remains.
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Affiliation(s)
- Sandeep Saluja
- Senior Resident, Department of Anatomy, Maulana Azad Medical College , New Delhi, India
| | - Sachin Patil
- Senior Resident, Department of Anatomy, Maulana Azad Medical College , New Delhi, India
| | - Neelam Vasudeva
- Director, Professor and HOD, Department of Anatomy, Maulana Azad Medical College , New Delhi, India
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Koktekir E, Toktas ZO, Seker A, Akakin A, Konya D, Kilic T. Anterior transpedicular screw fixation of cervical spine: Is it safe? Morphological feasibility, technical properties, and accuracy of manual insertion. J Neurosurg Spine 2015; 22:596-604. [DOI: 10.3171/2014.10.spine14669] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
Due to lack of construct stability of the current anterior cervical approaches, supplemental posterior cervical approaches are frequently employed. The use of an anterior-only approach with anterior transpedicular screws (ATPSs) has been proposed as a means of providing 3-column fixation. This study was designed to investigate the feasibility of anterior transpedicular screw (ATPS) fixation of cervical spine, to obtain the morphological measurements for technical prerequisites, and to evaluate the accuracy of the ATPS using fluoroscopy.
METHODS
The study included both radiological and anatomical investigations. The radiological investigations were based on data from cervical spine CT scans performed in 65 patients. Technical prerequisites of ATPS were calculated using OsiriX for Mac OS. In the anatomical part of the study, 30 pedicles (C3–7) from 6 formalin-preserved cadavers were manually instrumented. Measurements obtained included pedicle width (PW), pedicle height (PH), pedicle transverse angle (PTA), distance of the entry point from the midline (DEPM), and distance of the entry point from the superior endplate (DEPSEP). The authors also analyzed screw position in the manually instrumented vertebrae.
RESULTS
The mean PW and PH values showed a tendency to increase from C-3 to C-7 in both males and females. The means were significantly larger for both PW and PH in males than in females at all levels (p = 0.001). The overall mean PTA value was significantly lower at C-7 (p < 0.0001). The mean value for the distance of entry point from the midline (DEPM) represented a point at the contralateral side of the pedicle for every level except C-7. The mean DEPSEP values showed significant differences between all levels (p < 0.0001). Seven of the 30 screws were identified as breaching the pedicle (23.3%); these screw malplacements were seen at C-3 (3 screws), C-4 (2 screws), and C-5 (2 screws).
CONCLUSIONS
The morphological measurements of this study demonstrated that ATPS fixation is feasible in selected cases. They indicate that ATPS insertion using a fluoroscopy-assisted pedicle axis view is safe at the C-6 and C-7 levels, but the results at the other levels did not prove the safety of this technique.
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Affiliation(s)
| | | | - Askin Seker
- 3Department of Neurosurgery, Marmara University, Istanbul, Turkey
| | - Akin Akakin
- 2 Department of Neurosurgery, Bahcesehir University; and
| | - Deniz Konya
- 2 Department of Neurosurgery, Bahcesehir University; and
| | - Turker Kilic
- 2 Department of Neurosurgery, Bahcesehir University; and
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Translaminar Screw Fixation in the Upper Thoracic Spine: Computed Tomography-Based Quantitative Laminar Analysis and Feasibility Study of Translaminar Virtual Screw Placement. Cell Biochem Biophys 2015; 73:191-8. [PMID: 25711188 DOI: 10.1007/s12013-015-0618-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Translaminar screws (TLS) offer an alternative to pedicle screw fixation in the upper thoracic spine. Although some studies have described the anatomy of the laminae at the upper thoracic spine, computed tomography (CT) imaging is the modality of choice for presurgical planning. The characteristics of upper thoracic lamina in healthy Han adults have not been ascertained for the safe placement of TLSs. To determine the measurements (the diameter, maximal screw length, and optimal screw trajectory) required for safe TLSs placement in the T1-3 by CT scan evaluation, forty patients (20 men, 20 women), age (48.2 ± 13.9) years (range 19-78 years), were involved in the study from December 2008 to June 2012. Patients received a standardized axial bone-window CT imaging at T1-3, and had no evidence of spinal trauma, bone defect, or deformity. For each lamina, the height, thickness (outer cortical and inner cancellous), maximal screw length, and the crossing angle of the lamina were measured using Syngo 3D software and statistically analyzed. There were no significant differences between the left and right sides for each of the measurements (P > 0.05), but significant differences were determined between males and females for some measurements. The thickness of the laminar outer cortical diameter for the axial reconstruction was higher than that for the sagittal reconstruction (P < 0.01). The T1 lamina was estimated to accommodate, on average, a 4.2-mm longer screw than the T2 lamina, and a 5.7-mm longer screw than the T3 lamina. Most laminae could accept a 4.0-mm screw with a 1.0-mm clearance. Thus, it is more reasonable and accurate to select screw sizes according to the measurement of laminar thickness in the parasagittal reconstruction of the CT scan. T1 crossing laminar screws were successfully placed, without impingement to the spinal canal. Based on the CT evaluation, there are no anatomical limitations to the placement of TLSs at T1-3 in Chinese patients. Gender differences were noted in the superior thoracic vertebrae for dimensions of the laminae, which must be considered when placing TLSs at these levels. The TLSs add to the surgeon's armamentarium for instrumented fixation of the upper thoracic vertebrae.
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Abstract
BACKGROUND Cervical pedicle screw fixation is an effective method for treating traumatic and non traumatic injuries. But many studies have reported higher incidence of cervical pedicle penetration, so many research efforts have aimed at improving the accuracy of cervical screw fixation. Most of the anatomical studies on cervical pedicle screw placement previously published focused on the measurements of anatomical parameters, the entry point of pedicle screw is vague. We preliminarily designed a C3, C4 and C5 pedicle screw fixation method that had clear entry point and clinical cases confirmed that this method is feasible and safe. So we did this study of cervical pedicle screw fixation for C6 and C7 vertebrae. MATERIALS AND METHODS Fifteen cervical vertebrae specimens were prepared and bilateral pedicle screws were manually inserted into C6 and C7. The intersection of the horizontal line through the midpoint of the transverse process root and the vertical line through the intersection of the posterolateral and posterior planes of the isthmus was the entry point. The screws were inserted along the axis of the pedicle, with the screw axis coinciding with the pedicle. The pedicle was truncated axially and sagittally along the trajectory and the narrowest pedicular height (PH), pedicular width (PW), overall length of the screw channel (LSC), transverse angle (E) and vertical angle (F) were measured. RESULTS In C6, the PW and PH were 6.12 ± 0.78 and 7.48 ± 0.81 mm, respectively. In C7, the PW and PH were 6.85 ± 0.73 and 8.03 ± 0.38 mm, respectively. The LSC was 30.83 ± 0.91 mm. Two E angles were identified, namely E1 and E2 and their values were 89.61 ± 1.24 and 59.71 ± 1.10°, respectively. Meanwhile, F averaged 75.86 ± 1.12°. CONCLUSION The intersection of the horizontal line through the midpoint of the transverse process root and vertical line through the intersection of the posterolateral and posterior planes of the isthmus can be used as an entry point for C6 and C7 pedicle screw fixation. The screws should be inserted at 60 or 90° with the posterolateral isthmus in the horizontal plane and at 75° with the posterior isthmus in the sagittal plane. The LSC should not exceed 30 mm.
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Affiliation(s)
- Ye Li
- Department of Orthopaedic Surgery, China-Japan Union Hospital of Jilin University, Changchun 130031, China
| | - Jingchen Liu
- Department of Orthopaedic Surgery, China-Japan Union Hospital of Jilin University, Changchun 130031, China,Address for correspondence: Prof. Jingchen Liu, Department of Orthopaedic Surgery, China-Japan Union Hospital of Jilin University, No. 126 Xiantai Street, Changchun 130031, China. E-mail:
| | - Yulong Liu
- Department of Orthopaedic Surgery, China-Japan Union Hospital of Jilin University, Changchun 130031, China
| | - Yuntao Wu
- Department of Orthopaedic Surgery, China-Japan Union Hospital of Jilin University, Changchun 130031, China
| | - Qingsan Zhu
- Department of Orthopaedic Surgery, China-Japan Union Hospital of Jilin University, Changchun 130031, China
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Wasinpongwanich K, Paholpak P, Tuamsuk P, Sirichativapee W, Wisanuyotin T, Kosuwon W, Jeeravipoolvarn P. Morphological study of subaxial cervical pedicles by using three-dimensional computed tomography reconstruction image. Neurol Med Chir (Tokyo) 2014; 54:736-45. [PMID: 25169140 PMCID: PMC4533368 DOI: 10.2176/nmc.oa.2013-0287] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Malpositioning of cervical screws risks neurovascular injury. A cervical screw fixation system can provide proper rigidity, alignment correction, and high rates of fusion afforded by high pullout biomechanical strength. The objective is to assess the dimensions and axis of the C3–C7 cervical pedicles. A 1-mm slice thickness computed tomography (CT) scan of the cervical spine of 30 patients (15 males, 15 females) were analyzed and reconstructed in three-dimensions using Mimics® 10.01 software. We measured pedicle axis length (PAL), pedicle and lateral mass length (PL-LM), pedicle length (PL), outer pedicle width (OPW), and pedicle transverse angle (PTA) from the axial image and outer pedicle height (OPH) and pedicle sagittal angle (PSA) from the sagittal image. The OPH and OPW at all subaxial cervical spines were suitable for insertion of 3.5 mm cervical pedicle screws. PSA was directed cranially at C3 to C5 (13.84, 7.09, and 2.71) and directed caudally at C6 and C7 (–4.55, –6.94). PTA was greatest at C5 and smallest at C7. The respective difference between the left and right side for nearly all parameters was not statistically significant (except for C6 PL and C7 OPH). Females had a significantly smaller OPH and OPW than males at nearly all levels. The PTA was not significantly different between the sexes. Cervical pedicle screw fixation in the Thai population can be safely performed and guidelines for insertion at each vertebra documented. Appropriate preoperative planning is necessary to achieve safe and accurate placement of the screws.
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Computed tomographic morphometric analysis of cervical pedicles in a multi-ethnic Asian population and relevance to subaxial cervical pedicle screw fixation. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2014; 24:120-6. [PMID: 25155836 DOI: 10.1007/s00586-014-3526-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 08/17/2014] [Accepted: 08/18/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE Pedicle screw instrumentation provides optimal stabilization of the cervical spine complex, but is associated with risk of neurovascular injury. Sex and ethnic disparities may compromise safe and accurate screw placement. Therefore, a comprehensive analysis of pedicle dimensions derived from computed tomography scans is pertinent for our multi-ethnic population. METHODS Cervical spine CT of 50 patients without significant cervical spine pathology was selected. Pedicle width (PW), pedicle height (PH) and pedicle transverse angle (PTA) from C3 to C7 were measured and subsequently analyzed for sex and ethnic differences. RESULTS The smallest mean PW was at C4 in males and C3 in females. Mean PW for males was significantly greater than females at all levels (P < 0.05). 8 % of our population had at least one PW < 4.00 mm. At C5, C6 and C7 there is zero percent incidence of PW < 4.00 mm. The mean PH in males was significantly greater than females at all levels (P < 0.05), but no statistically significant sex differences in mean PTA values were found. There were significant ethnic differences in mean PW of males at C4, C5 and C7 (P < 0.05) and mean PH of females at C3, C4 and C7 (P < 0.05). CONCLUSIONS Transpedicular screw fixation is generally feasible in our population except for 8 % with at least one PW < 4.00 mm. However, in view of significant sex and ethnic morphometric variability, pre-operative CT evaluation together with image-guided screw placement is highly advised to ensure safety and accuracy.
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Chanplakorn P, Kraiwattanapong C, Aroonjarattham K, Leelapattana P, Keorochana G, Jaovisidha S, Wajanavisit W. Morphometric evaluation of subaxial cervical spine using multi-detector computerized tomography (MD-CT) scan: the consideration for cervical pedicle screws fixation. BMC Musculoskelet Disord 2014; 15:125. [PMID: 24725394 PMCID: PMC3991875 DOI: 10.1186/1471-2474-15-125] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/08/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cervical pedicle screw (CPS) insertion is a technically demanding procedure. The quantitative understanding of cervical pedicle morphology, especially the narrowest part of cervical pedicle or isthmus, would minimize the risk of catastrophic damage to surrounding neurovascular structures and improve surgical outcome. The aim of this study was to investigate morphology and quantify cortical thickness of the cervical isthmus by using Multi-detector Computerized Tomography (MD-CT) scan. METHODS The cervical CT scans were performed in 74 patients (37 males and 37 females) with 1-mm slice thickness and then retro-reconstructed into sagittal and coronal planes to measure various cervical parameters as follows: outer pedicle width (OPW), inner pedicle width (IPW), outer pedicle height (OPH), inner pedicle height (IPH), pedicle cortical thickness, pedicle sagittal angle (PSA), and pedicle transverse angle (PTA). RESULTS Total numbers of 740 pedicles were measured in this present study. The mean OPW and IPW significantly increased from C3 to C7 while the mean OPH and IPH of those showed non-significant difference between any measured levels. The medial-lateral cortical thickness was significantly smaller than the superior-inferior one. PTA in the upper cervical spine was significantly wider than the lower ones. The PSA changed from upward inclination at upper cervical spine to the downward inclination at lower cervical spine. CONCLUSIONS This study has demonstrated that cervical vertebra has relatively small and narrow inner pedicle canal with thick outer pedicle cortex and also shows a variable in pedicle width and inconsistent transverse angle. To enhance the safety of CPS insertion, the entry point and trajectories should be determined individually by using preoperative MD-CT scan and the inner pedicle width should be a key parameter to determine the screw dimensions.
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Affiliation(s)
| | | | | | | | | | | | - Wiwat Wajanavisit
- Department of Orthopedics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 270 Rama VI Road, Phaya Thai, Ratchathewi, Bangkok 10400, Thailand.
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Li A, Wang Q, Gao Y, Yang J, Wang Y, Li XK. Preoperative design of expansive open-door laminoplasty: a computer-assisted morphometric analysis. ACTA ACUST UNITED AC 2013; 18:201-4. [PMID: 23895435 DOI: 10.3109/10929088.2013.821169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Whereas the expansive open-door laminoplasty (EL) has been applied widely and the bone gutter on the hinge side is essential for EL, little is known regarding the mandatory width of the bone gutter. This study addressed the essential parameters of bone gutters for EL. Preoperative axial CT images of 20 patients suffering from cervical myelopathy were downloaded and entered into a computer. EL was then simulated using a computer-assisted technique and the thickness of the laminae at the gutter sites was measured. Accordingly, the width of the bone gutter was linked mathematically with the angle of the lifted lamina and the thickness of the lamina at the lamina-lateral mass junction. Furthermore, the average thickness of the laminae at the gutter site was 6.19 mm, and the appropriate bone gutter for EL was 5.13 to 7.15 mm. The width of the bone gutter can thus be planned precisely preoperatively, which may help improve the safety and accuracy of expansive open-door laminoplasty.
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Affiliation(s)
- Ang Li
- School of Stomatology, Fourth Military Medical University , Xi'an , China
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Abstract
STUDY DESIGN Applied anatomical study and clinical application. OBJECTIVE To design and optimize the method of cervical pedicle screw placement for cervical vertebrae C3-C5, and to test it in clinical applications. SUMMARY OF BACKGROUND DATA Most of the anatomical studies on cervical pedicle screw placement previously published focused on the lower cervical vertebrae. Clinically, it is much more difficult to place C3, C4, and C5 screws than C6 and C7 screws; therefore, anatomical measurements of C3-C5 pedicles and design of an appropriate screw placement method are required. METHODS A total of 20 cervical vertebrae specimens were prepared, and bilateral pedicle screws were manually inserted for C3-C5. The intersection of the horizontal line through the midpoint of the transverse process root and the vertical line through the mediolateral third of the superior articular process was used as the entry point. The screws were inserted along the axis of the pedicle, with the axis of the screw coinciding with that of the pedicle. The specimens were truncated along the horizontal or sagittal plane of the pedicle, and a variety of measurements were made to determine appropriate screw type and placement. Finally, this screw fixation technique was applied in clinical situations with the placement of 26 C3 screws, 26 C4 screws, and 38 C5 screws. RESULTS Pedicular height was larger than pedicular width for the same segment of C3-C5, and pedicular width of the different segments did not significantly vary. The lengths of the screw channels for C3-C5 screw placement were similar. The transverse angles of C3-C5 segments displayed a decreasing trend, whereas the vertical angles did not. In all clinical cases, all screws were properly within the pedicles examined using postoperative computed tomography scan. Only 1 C3 screw penetrated the medial cortex and slightly entered the spinal canal, but no clinical symptoms occurred. CONCLUSION The intersection of the horizontal line through the midpoint of the transverse process root and the vertical line through the mediolateral third of the superior articular process represents a superior frame of reference for the entry point for C3-C5 pedicle screw fixation. Clinically, we recommend the transverse angles to be 90° for C3 and 80° for C4 and C5, and the vertical angles to be 70° for C3-C5. We found that screws with a diameter of 3.5 mm and length of 20 mm or 22 mm to be safe, objective, and reliable.
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Lee SH, Kim KT, Abumi K, Suk KS, Lee JH, Park KJ. Cervical Pedicle Screw Placement Using the “Key Slot Technique”. ACTA ACUST UNITED AC 2012; 25:415-21. [DOI: 10.1097/bsd.0b013e3182309657] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Evangelopoulos D, Kontovazenitis P, Kouris S, Zlatidou X, Benneker L, Vlamis J, Korres D, Efstathopoulos N. Computerized tomographic morphometric analysis of the cervical spine. Open Orthop J 2012; 6:250-4. [PMID: 22802920 PMCID: PMC3395889 DOI: 10.2174/1874325001206010250] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Revised: 04/30/2012] [Accepted: 05/02/2012] [Indexed: 11/22/2022] Open
Abstract
Background: Detailed knowledge of cervical canal and transverse foramens’ morphometry is critical for understanding the pathology of certain diseases and for proper preoperative planning. Lateral x-rays do not provide the necessary accuracy. A retrospective morphometric study of the cervical canal was performed at the authors’ institution to measure mean dimensions of sagittal canal diameter (SCD), right and left transverse foramens’ sagittal (SFD) and transverse (TFD) diameters and minimum distance between spinal canal and transverse foramens (dSC-TF) for each level of the cervical spine from C1-C7, using computerized tomographic scans, in 100 patients from the archives of the Emergency Room. Results: Significant differences for SCD were detected between C1 and the other levels of the cervical spine for both male and female patients. For the transverse foramen, significant differences in sagittal diameters were detected at C3, C4, C5 levels. For transverse diameters, significant differences at C3 and C4 levels. A significant difference of the distance between the transverse spinal foramen and the cervical canal was measured between left and right side at the level of C3. This difference was equally observed to male and female subjects. Conclusion: CT scan can replace older conventional radiography techniques by providing more accurate measurements on anatomical elements of the cervical spine that could facilitate diagnosis and preoperative planning, thus avoiding possible trauma to the vertebral arteries during tissue dissection and instrument application.
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Affiliation(s)
- Ds Evangelopoulos
- 3 Orthopaedic Department, University of Athens, KAT hospital, Athens, Greece
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Ethnic differences in pedicle and bony spinal canal dimensions calculated from computed tomography of the cervical spine: a review of the English-language literature. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2012; 21:1451-8. [PMID: 22526698 DOI: 10.1007/s00586-012-2295-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 03/18/2012] [Accepted: 03/29/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE The aims of this study were to review published data on pedicle dimensions and bony spinal canal diameters calculated from CT examinations of the cervical spine through the English-language literature and analyze these data for ethnic disparities and similarities. MATERIALS AND METHODS The authors reviewed the literature on "pedicle" and "spinal canal" by conducting a bibliographic search using PubMed, Ovid MEDLINE, and Science Direct from January 1985 to December 2010. After evaluating all of the selected abstracts, we ultimately selected 19 studies involving living subjects: 12 studies on pedicle dimensions and 7 on spinal canal diameters. The four parameters, pedicle width (PW), pedicle transverse angle (PTA), anterior-posterior diameter of the spinal canal (APD), and transverse diameter of the spinal canal (TD), were analyzed at the relevant levels from C3 to C7. In addition, the values for pedicle dimensions and spinal canal diameters in the European/American populations were compared using the data from Asian populations as a baseline. RESULTS The smallest mean PW was found at C4 in the male (5.1 mm) and female populations (4.1 mm); the largest mean PW was found at C7 in both male (7.7 mm) and female populations (7 mm). The PW in males was greater than in females at the majority of levels. The smallest mean PTA was found at C7 in both male (33.4°) and female populations (33°); the largest mean PTA was found at C4 in both male (53.2°) and female populations (52.1°). The overall PW, PTA, APD, and TD ratio of European/American to Asian populations was 91.4-98.8, 99.6-106.2, 110.7-122, and 100-108.3 %, respectively. CONCLUSION Although our cervical spine CT data were suggestive of possible ethnic differences in spinal canal morphology, our analysis failed to identify significant ethnic disparity in pedicle dimensions despite potential differences in physique between populations.
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Pelton MA, Schwartz J, Singh K. Subaxial cervical and cervicothoracic fixation techniques--indications, techniques, and outcomes. Orthop Clin North Am 2012; 43:19-28, vii. [PMID: 22082626 DOI: 10.1016/j.ocl.2011.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The subaxial and cervicothoracic junction is a relatively difficult area for spine surgeons to navigate. Because of different transitional stressors at the junction of the smaller cervical vertebrae and the larger thoracic segments, proximity to neurovascular structures, and complex anatomy, extreme care and precision must be assumed during fixation in these regions. Lateral mass screws, pedicle screws, and translaminar screws are currently the standard of choice in the subaxial cervical and upper thoracic spine. This article addresses the relevant surgical anatomy, pitfalls, and pearls associated with each of these fixation techniques.
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Affiliation(s)
- Miguel A Pelton
- Department of Orthopedic Surgery, Rush University Medical Center, 1611 West Harrison Street, Chicago, IL 60612, USA
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Cervical pedicle screw insertion using a gutter entry point at the transitional area between the lateral mass and lamina. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2011; 21:353-8. [PMID: 21830076 DOI: 10.1007/s00586-011-1969-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 06/27/2011] [Accepted: 07/31/2011] [Indexed: 10/17/2022]
Abstract
PURPOSE The purpose of this study was to describe a free-hand pedicle screw insertion technique and to evaluate the accuracy of pedicle screw placement and validity of pedicle screw fixation in patients with subaxial cervical spine injuries. METHODS We retrospectively reviewed 32 consecutive patients with subaxial cervical spine injuries who underwent posterior cervical fixation using our cervical pedicle screw (CPS) insertion technique. We also assessed the clinical and radiological outcomes and the accuracy of pedicle screw placement. RESULTS The mean preoperative kyphosis was 4.0°, which was corrected to -5.2° after the operation, and the mean kyphosis angle was -4.4° at the final follow-up. The mean preoperative disc height ratio was 81.9%, and it improved to 105.4% after the operation, which was maintained until the final follow-up measurement of 103.4%. Bony union was achieved, and there were no instrumentation failures in any patient. Overall, 127 pedicle screws were inserted, of which 112 (88.1%) were classified as grade 1 (exact intrapedicular screw positioning), 10 (7.8%) as grade 2 (perforation <50% of the screw diameter), and 5 (3.9%) as grade 3 (perforation more than 50% of the screw diameter). CONCLUSION In our technique, a gutter is created using a high-speed burr at the transitional area between the lateral mass and lamina similar to the procedure in double-door laminoplasty to identify an entry point for CPS insertion. It is easy for general spine surgeons to identify a CPS insertion entry point using our technique.
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Abstract
STUDY DESIGN A systematic review of the published literature was conducted specifically looking at studies reporting linear dimension and angular projection data on the anatomy of the cervical pedicle (C1-C7) via radiography or direct measurement. OBJECTIVE This study aimed to report a more accurate set of dimension data and identify differences based on race and gender, increasing the sample size by aggregating similar data of prior studies measuring the cervical pedicle in Asian, European/American, male, and female populations. SUMMARY OF BACKGROUND DATA A wide variation in the reports of the dimensions and projections of the cervical pedicle exist partly due to the uniqueness of this structure as well as the effects of small sample sizes and variable races and genders of sample populations of previous studies. METHODS An extensive literature search was executed, and identified articles were reviewed. A comprehensive database was constructed for synthesis of the identified studies. Subgroups were determined based on the type of population (race, gender, location of study) and radiographic or direct cadaveric measurement. Descriptive statistics were used to analyze and compare these subgroups including: means, standard deviations, and Student t test with the Bonferroni adjustment. RESULTS In total, the current study reports on 33 studies with the measurements of 1311 partial and complete cervical spines. At a 95% confidence interval statistically significant differences between races were found only at C3 and C4 levels in the pedicle axis length. Male-to-female significant differences existed only at the pedicle axis length of C5 in the Asian population, while sex differences existed in the outer pedicle width and height of C3, C4, C5, C6, and C7 in the European/American population. CONCLUSION The current study has found that there is no statistical difference in measuring the cervical pedicle via radiography (CT) or directly. There are more significant differences comparing the cervical pedicles of males and females in the European/American population than exists in the Asian population (specifically in pedicle width and height). There are also significant differences at C3 and C4 cervical pedicle between the Asian and European/American population (specifically in the pedicle axis length and transverse angle).
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Morphological analysis of the cervical pedicles, lateral masses, and laminae in developmental canal stenosis. Spine (Phila Pa 1976) 2010; 35:E1381-5. [PMID: 21030896 DOI: 10.1097/brs.0b013e3181e8958f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Retrospective cross-sectional study. OBJECTIVE This study aimed to elucidate the relationship between developmental spinal canal stenosis (DCS) and morphologic features in the cervical spine by comparing the features between DCS and nondevelopmental spinal canal stenosis (NDCS). SUMMARY OF BACKGROUND DATA DCS is an important predisposing factor for cervical myelopathy. Further, various posterior cervical spinal instrumentations have been developed. However, no study has specifically addressed the cervical posterior morphology of DCS. METHODS A total of 52 consecutive patients underwent cervical spine computed tomography myelography. Axial images of the largest pedicle diameter were selected from C3 to C7 vertebrae and 260 images were analyzed. The following parameters were measured: spinal canal longitudinal diameter (SCLD), spinal canal transverse diameter, osseous spinal canal area, dural sac area, spinal cord area, pedicle outer width, pedicle axis length, pedicle transverse angulation, lateral mass longitudinal diameter, lateral mass transverse diameter, lamina outer width, and lamina axis length. The participants were classified into 2 groups: DCS group (SCLD <12 mm at any level) and NDCS group (SCLD ≧12 mm at all levels). RESULTS The mean osseous spinal canal area and dural sac area at C3-C5 in the DCS group were less than those in the NDCS group. The mean spinal cord area did not differ significantly at C3-C7 between the groups. The mean pedicle outer width at C6 and C7 in the DCS group was less than that in NDCS group. The mean lateral mass transverse diameter at C5 and mean lateral mass longitudinal diameter at C3, C5, and C6 in the DCS group were less than those in the NDCS group. CONCLUSION Myelopathy is expected to progress in patients with DSC and these patients with severe neurologic symptoms may need cervical operation. However, posterior screw insertions should be considered more carefully than in NDCS patients.
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Location of the transverse foramen in the subaxial cervical spine in a young asymptomatic population. Spine (Phila Pa 1976) 2010; 35:E514-9. [PMID: 20445473 DOI: 10.1097/brs.0b013e3181ce5332] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Computerized tomography of the subaxial cervical spine in 98 young, asymptomatic North American volunteers. OBJECTIVE To provide normative data on subaxial transverse foramen dimensions and location in relation to surgical landmarks routinely used during operative intervention in the anterior cervical spine. SUMMARY OF BACKGROUND DATA Vertebral artery injury during anterior cervical spinal surgery is a rare but potentially catastrophic injury. There have been no prior studies in a large group of young, asymptomatic subjects without pathology and where the age, weight, and gender are known. There are no published computerized tomography data evaluating distances between the tip of the uncovertebral joint and the medial margin of the uncovertebral joint, 2 commonly used surgical landmarks. METHODS Axial and reconstructed coronal computerized tomography images of cervical vertebrae from C3 to C7 in 98 asymptomatic young volunteers were analyzed to measure interforaminal distance, transverse foramen distance from anterior and posterior vertebral body margins, transverse foramen dimensions, and transverse foramen medial margin distance from the uncus tip and medial margin. RESULTS All measurements were significantly different between males and females, with smaller female dimensions. Interforaminal distance gradually increased from C3 to C7. Transverse foramen anterior margin in relation to the anterior vertebral body was significantly more posterior at C7 compared with the C3-C6 levels. Transverse foramen posterior margin in relation to the vertebral body posterior margin gradually moved anteriorly from C3 to C6 and then posterior again at C7. The vertebral uncus tip and medial margin in relation to the medial transverse foramen averaged 2.8 mm and 5.7 mm for males and 2.7 mm and 5.3 mm for females from C3 to C6. CONCLUSION.: Useful morphometric data are provided that may assist the operating surgeon to avoid vertebral artery injury during anterior surgical approaches to the cervical spine. The medial margin of the uncovertebral joint may be the safest landmark to avoid vertebral artery injury during anterior cervical disc surgery. The vertebral artery is at increased risk of injury during neural decompression at more cephalad levels.
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Zheng X, Chaudhari R, Wu C, Mehbod AA, Transfeldt EE. Subaxial cervical pedicle screw insertion with newly defined entry point and trajectory: accuracy evaluation in cadavers. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2009; 19:105-12. [PMID: 19916031 DOI: 10.1007/s00586-009-1213-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 10/21/2009] [Accepted: 11/03/2009] [Indexed: 10/20/2022]
Abstract
Successful placement of cervical pedicle screws requires accurate identification of both entry point and trajectory. However, literature has not provided consistent recommendations regarding the direction of pedicle screw insertion and entry point location. The objective of this study was to define a guideline regarding the optimal entry point and trajectory in placing subaxial cervical pedicle screws and to evaluate the screw accuracy in cadaver cervical spines. The guideline for entry point and trajectory for each vertebra was established based on the recently published morphometric data. Six fresh frozen cervical spines (C3-C7) were used. There were two men and four women. After posterior exposure, the entry point was determined and the cortical bone of the entry point was removed using a 2-mm burr. Pilot holes were created with a cervical probe based on the guideline using fluoroscopy. After tapping, 3.5-mm screws with appropriate length were inserted. After screw insertion, every vertebra was dissected and inspected for pedicle breach. The pedicle width, height, pedicle transverse angulation and actual screw insertion angle were measured. A total of 60 pedicle screws were inserted. No statistical difference in pedicle width and height was found between the left and right sides for each level. The overall accuracy of pedicle screws was 83.3%. The remaining 13.3% screws had noncritical breach, and 3.3% had critical breach. The critical breach was not caused by the guideline. There was no statistical difference between the pedicle transverse angulation and the actual screw trajectory created using the guideline. There was statistical difference in pedicle width between the breach and non-breach screws. In conclusion, high success rate of subaxial cervical pedicle screw placement can be achieved using the recently proposed operative guideline and oblique views of fluoroscopy. However, careful preoperative planning and good surgical skills are still required to ensure screw placement accuracy and to reduce the risk of neural and vascular injury.
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Affiliation(s)
- Xiujun Zheng
- Foundation for the Advancement of Spine Knowledge, 913 E 26th St, Piper Building, Suite 600, Minneapolis, MN 55404, USA.
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