Morphometric Study of the Thoracic Vertebral Pedicle in an Indian Population

Datir, Sandeep; Mitra, Sajal R.

doi:10.1097/00007632-200406010-00004

Cited by 68 publications

(87 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Ludwig's study indicated that using a 3.5 mm diameter screw and if 4.5 mm was used as a cut-off for attempting screw insertion, only 2% of the screws inserted would be likely to result in harm. The results concurred with clinical recommendations defining cut-offs of 4.0-4.5 mm using 3.5 mm screws at C3-7 [7,12,16,56], and 5 mm for pedicle screws in T1 [54]. At all with our current results following fluoroscopically assisted manual insertion of 3.5 mm diameter ATPS, safe placement is assumed at the C6 to T1-levels with pedicles showing an OPW of C5 mm.…”

Section: Risk Factors For Pedicle Perforationssupporting

confidence: 90%

“…The current study confirmed that the cervical pedicle dimensions tend to increase in size from C3 to T1 [21], and that the pedicle transverse diameter (OPW) is the main determinant of critical pedicle perforations and of the maximum screw sizes to be used [6,54,55] with increasing accuracy of pedicle screw insertions at the caudad levels C6 to T1 [7,10,11,15]. In a study of Karaikovic et al [6] using the funnel technique, critical perforations occurred in 10.5% at C5, 5.3% at C6, and 0% at C7, which were 13.0% at C5 in the current series, but 0% at C6 to T1.…”

Section: Risk Factors For Pedicle Perforationssupporting

confidence: 77%

See 1 more Smart Citation

Cervical anterior transpedicular screw fixation (ATPS)—Part II. Accuracy of manual insertion and pull-out strength of ATPS

et al. 2008

View full text Add to dashboard Cite

Reconstruction after multilevel decompression of the cervical spine, especially in the weakened osteoporotic, neoplastic or infectious spine often requires circumferential stabilization and fusion. To avoid the additional posterior surgery in these cases while increasing rigidity of anterior-only screw-plate constructs, the authors introduce the concept of anterior transpedicular screw (ATPS) fixation. We demonstrated its morphological feasibility as well as its indications in a previous study in Part I of our project. Consequently, the objectives of the current study were to assess the ex vivo accuracy of placing ATPS into the cervical vertebra as well as the biomechanical performance of ATPS in comparison to traditional vertebral body screws (VBS) in terms of pull-out strength (POS). Twenty-three ATPS were inserted alternately to two screws into the pedicles and vertebral bodies, respectively, of six cadaveric specimens from C3-T1. For insertion of ATPS, a manual fluoroscopically assisted technique was used. Preand post insertional CT-scans were used to assess accuracy of ATPS insertion in the axial and sagittal planes. A newly designed grading system and accuracy score were used to delineate accuracy of ATPS insertion. Following insertion of screws, 23 ATPS and 22 VBS were subjected to pull-out testing (POT). The bone mineral density (BMD) of each specimen was assessed prior to POT. Statistical analysis showed that the incidence of correctly placed screws and non-critical pedicles breaches in axial plane was 78.3%, and 95.7% in sagittal plane. Hence, according to our definition of ''critical'' pedicle breach that exposes neurovascular structures at risk, 21.7% (n = 5) of all ATPS inserted showed a critical pedicle breach in axial plane. Notably, no critical pedicle perforation occurred at the C6 to T1 levels. Pull-out testing of ATPS and VBS revealed that pull-out ( ) 17:539-555 DOI 10.1007 resistance of ATPS was 2.5-fold that of VBS. Mean POS of 23 ATPS with a mean BMD of 0.566 g/cm 2 and a mean osseus screw purchase of 27.2 mm was 467.8 N. In comparison, POS of 22 VBS screws with a mean BMD of 0.533 g/cm 2 and a mean osseus screw purchase of 16.0 mm was 181.6 N. The difference in ultimate pull-out strength between the ATPS and VBS group was significant (p \ 0.000001). Also, accuracy of ATPS placement in axial plane was shown to be significantly correlated with POS. In contrast, there was no correlation between screw-length, BMD, or level of insertion and the POS of ATPS or VBS. The study demonstrated that the use of ATPS might be a new technique worthy of further investigation. The use of ATPS shows the potential to increase construct rigidity in terms of screw-plate pull-out resistance. It might diminish construct failures during anterior-only reconstructions of the highly unstable decompressed cervical spine.123 Eur Spine J

show abstract

Section: Risk Factors For Pedicle Perforationssupporting

confidence: 90%

Section: Risk Factors For Pedicle Perforationssupporting

confidence: 77%

Cervical anterior transpedicular screw fixation (ATPS)—Part II. Accuracy of manual insertion and pull-out strength of ATPS

et al. 2008

View full text Add to dashboard Cite

show abstract

“…The morphometric profile of the thoracic pedicles in our study is comparable to figures quoted in other Asian anatomical studies [5,19]. We do not routinely perform computed tomography of thoracic pedicles prior to insertion of the pedicle screws.…”

Section: Discussionsupporting

confidence: 86%

Safety of thoracic pedicle screw application using the funnel technique in Asians: a cadaveric evaluation

2009

View full text Add to dashboard Cite

The objective of this cadaveric study is to determine the safety and outcome of thoracic pedicle screw placement in Asians using the funnel technique. Pedicle screws have superior biomechanical as well as clinical data when compared to other methods of instrumentation. However, misplacement in the thoracic spine can result in major neurological implications. There is great variability of the thoracic pedicle morphometry between the Western and the Asian population. The feasibility of thoracic pedicle screw insertion in Asians has not been fully elucidated yet. A pre-insertion radiograph was performed and surgeons were blinded to the morphometry of the thoracic pedicles. 240 pedicle screws were inserted in ten Asian cadavers from T1 to T12 using the funnel technique. 5.0 mm screws were used from T1 to T6 while 6.0 mm screws were used from T7 to T12. Perforations were detected by direct visualization via a wide laminectomy. The narrowest pedicles are found between T3 and T6. T5 pedicle width is smallest measuring 4.1 ± 1.3 mm. There were 24 (10.0%) Grade 1 perforations and only 1 (0.4%) Grade 2 perforation. Grade 2 or worse perforation is considered significant perforation which would threaten the neural structures. There were twice as many lateral and inferior perforations compared to medial perforations. 48.0% of the perforations occurred at T1, T2 and T3 pedicles. Pedicle fracture occurred in 10.4% of pedicles. Intra-operatively, the absence of funnel was found in 24.5% of pedicles. In conclusion, thoracic pedicle screws using 5.0 mm at T1-T6 and 6.0 mm at T7-T12 can be inserted safely in Asian cadavers using the funnel technique despite having smaller thoracic pedicle morphometry.

show abstract

“…The aim of this study was to assess the pedicle anatomy in a Chinese population based on CT scans. Previous studies had shown significant interracial differences of thoracic pedicle morphometry [2,4,10]. Therefore, a complete morphometry database of the thoracic pedicle is needed to determine the safety margin of transpedicular fixation in our population.…”

Section: Introductionmentioning

confidence: 99%

Computed tomographic morphometry of thoracic pedicles: safety pedicle parameter measurement of the Chinese immature thoracic spine

Chen

Huang

et al. 2008

International Orthopaedics (SICOT)

View full text Add to dashboard Cite

Our objective was to quantify the morphometric characteristics of the pedicles of the Chinese immature thoracic spine. A total of 120 patients aged 5-14 years underwent standard thoracic computed tomography (CT). The patients were grouped according to age: group 1 (5-8 years of age), group 2 (9-11 years of age) and group 3 (12-14 years of age). Images were reformatted, and multiplanar reconstructions were used to attain images of thoracic pedicles on sagittal, coronal and transverse planes. The measurements included the inner and outer pedicle diameters on the transverse plane, pedicle sagittal diameter, pedicle length and the pedicle angle on the transverse. (1) Pedicle diameters on the transverse plane decreased gradually from T1 to T4 and increased gradually from T5 to T12. The shortest transverse diameter of the thoracic pedicle was T4 or T5. (2) The sagittal diameter was significantly larger than the transverse diameter except at T1. (3) The length of the pedicle from the posterior cortex to the anterior cortex of the vertebra increased from T1 to T12. (4) The pedicle angle decreased gradually from T1 to T8 and became negative below the level of T10. The length of the pedicle changed with age significantly, but the pedicle angle changed with age insignificantly. The success of transpedicular fixation requires a better understanding of morphological features at different ages and reasonable selection of the diameter, length and direction of the pedicle screws based on X-ray and CT films.

show abstract

Morphometric Study of the Thoracic Vertebral Pedicle in an Indian Population

Cited by 68 publications

References 17 publications

Cervical anterior transpedicular screw fixation (ATPS)—Part II. Accuracy of manual insertion and pull-out strength of ATPS

Cervical anterior transpedicular screw fixation (ATPS)—Part II. Accuracy of manual insertion and pull-out strength of ATPS

Safety of thoracic pedicle screw application using the funnel technique in Asians: a cadaveric evaluation

Computed tomographic morphometry of thoracic pedicles: safety pedicle parameter measurement of the Chinese immature thoracic spine

Contact Info

Product

Resources

About