Unilateral C1 Sagittal Split Fractures: An Unusual Entity Revisited

Felbaum, Daniel R.; Stewart, Jeffrey J; Suskin, Zaev D.; Gill, Waltus H.; Sandhu, Faheem A.

doi:10.1016/j.wneu.2017.09.206

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…These displacements were converted into load-displacement ratios to analyze the stability of the pedicle screws in each direction. A higher load-displacement ratio indicates better stability of the pedicle screws[ 17 ].…”

Section: Methodsmentioning

confidence: 99%

Biomechanical effects of posterior lumbar interbody fusion with vertical placement of pedicle screws compared to traditional placement

Jiang,

Zhao,

Zhang

et al. 2024

World J Clin Cases

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BACKGROUND The pedicle screw technique is widely employed for vertebral body fixation in the treatment of spinal disorders. However, traditional screw placement methods require the dissection of paraspinal muscles and the insertion of pedicle screws at specific transverse section angles (TSA). Larger TSA angles require more force to pull the muscle tissue, which can increase the risk of surgical trauma and ischemic injury to the lumbar muscles. AIM To study the feasibility of zero-degree TSA vertical pedicle screw technique in the lumbosacral segment. METHODS Finite element models of vertebral bodies and pedicle screw-rod systems were established for the L4-S1 spinal segments. A standard axial load of 500 N and a rotational torque of 10 N/m were applied. Simulated screw pull-out experiment was conducted to observe pedicle screw resistance to pull-out, maximum stress, load-displacement ratio, maximum stress in vertebral bodies, load-displacement ratio in vertebral bodies, and the stress distribution in pedicle screws and vertebral bodies. Differences between the 0-degree and 17-degree TSA were compared. RESULTS At 0-degree TSA, the screw pull-out force decreased by 11.35% compared to that at 17-degree TSA (P < 0.05). At 0-degree and 17-degree TSA, the stress range in the screw-rod system was 335.1-657.5 MPa and 242.8-648.5 MPa, separately, which were below the fracture threshold for the screw-rod system (924 MPa). At 0-degree and 17-degree TSA, the stress range in the vertebral bodies was 68.45-78.91 MPa and 39.08-72.73 MPa, separately, which were below the typical bone yield stress range for vertebral bodies (110-125 MPa). At 0-degree TSA, the load-displacement ratio for the vertebral bodies and pedicle screws was slightly lower compared to that at 17-degree TSA, indicating slightly lower stability (P < 0.05). CONCLUSION The safety and stability of 0-degree TSA are slightly lower, but the risks of screw-rod system fracture, vertebral body fracture, and rupture are within acceptable limits.

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Section: Methodsmentioning

confidence: 99%

Biomechanical effects of posterior lumbar interbody fusion with vertical placement of pedicle screws compared to traditional placement

Jiang,

Zhao,

Zhang

et al. 2024

World J Clin Cases

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“…Recently, the unilateral sagittal split fracture (USSF) of the C1 lateral mass (LM) was recognized as a rare variant of C1 atlas fracture 1, 2, 3, 4. The integrity of the transverse atlantal ligament (TAL) is a critical factor for determining the stability of C1 atlas fracture.…”

Section: Introductionmentioning

confidence: 99%

Clinical and radiological outcomes of conservative treatment for unilateral sagittal split fractures of C1 lateral mass

Kim

Park

et al. 2019

Acta Orthopaedica et Traumatologica Turcica

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ObjectiveThe aim of this study was to assess the effect of transverse atlantal ligament (TAL) integrity on clinical and radiological outcomes in patients with unilateral sagittal split fracture (USSF) of the C1 lateral mass (LM).MethodsTwenty-six consecutive patients (16 men and 10 women; mean age: 52 years (range: 32–69)) with C1 LM USSF were included in this study. Sixteen were TAL injury group (nine of type I injuries and seven of type II injuries according to Dickman's classification) and ten were TAL intact group. All cases were conservatively treated with a rigid brace for TAL intact or by halo-vest stabilization for TAL injury for three months. The mean follow-up was 16 months (range, 12–47 months). The results were compared with radiological assessment of fracture healing, LM displacement and Neck visual analog scale.ResultsAt the last follow-up, for TAL intact group, total LM displacement (LMD), unilateral LMD of fracture side, atlanto-dental interval, basion-dental interval, clivus canal angle, and atlanto-occipital joint axis angle were maintained compared to initial presentation. However, for TAL injury group, all radiological parameters were worsened. The worsening of radiological parameters was more severe in type I injury than type II injury except for total LMD and unilateral LMD. Neck visual analog scale significantly decreased and patient's satisfaction was higher in TAL intact group compared to TAL injury group.ConclusionConservative treatment for USSF of C1 LM with TAL injury failed to achieve healing of the fracture, which resulted in lateral displacement of C1 LM. This caused coronal and sagittal malalignment of occipitocervical junction, resulting in unsatisfactory clinical outcomes. Our results suggest that early surgical stabilization should be considered in USSF of C1 LM with TAL injury, especially type I injury. However, conservative treatment may be sufficient for a USSF of the C1 LM with TAL intact.Level of EvidenceLevel III, Therapeutic Study.

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“…Unilateral sagittal split fracture (USSF) of the C1 lateral mass (LM) has been recently recognized as a rare variant of C1 atlas fracture. [1–4] The most important factor in determining the stability of C1 atlas fracture is the presence or absence of transverse atlantal ligament (TAL) injury. If there is no TAL injury, the fracture is regarded as stable, and conservative treatment is performed.…”

Section: Introductionmentioning

confidence: 99%

“…Definitive diagnostic criteria to determine the stability of USSF of the C1 LM have yet to be established. [1–4] Jefferson fracture and USSF of the C1 LM are in the same category as C1 fracture. However, the 2 fracture entities are different in several aspects, including injury mechanism and pattern and severity of fracture.…”

Section: Introductionmentioning

confidence: 99%

Radiologic criteria to predict injury of the transverse atlantal ligament in unilateral sagittal split fractures of the C1 lateral mass

et al. 2019

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Unilateral sagittal split fracture (USSF) of the C1 lateral mass (LM) has been recently recognized as a rare variant of C1 atlas fracture. To date, there has been no study to investigate whether radiologic criteria can be applied to determine the presence or absence of transverse atlantal ligament (TAL) injury in USSF of the C1 LM.Twenty six consecutive cases of USSF of the C1 LM were included in this study. According to Dickman classification, 16 cases were TAL injury, and 10 cases were TAL intact. Radiologic parameters were measured and compared between the 2 groups.Total LM displacement (LMD) of the 2 sides (5.9 ± 2.0 mm vs 1.2 ± 2.0 mm), unilateral LMD of the fracture side (4.3 ± 1.2 mm vs 1.0 ± 1.1 mm), atlanto-dental interval (ADI) (2.0 ± 0.9 mm vs 1.5 ± 0.4 mm), and fracture gap (6.9 ± 2.7 mm vs 2.1 ± 1.1 mm) were statistically higher in the TAL injury group than the TAL intact group. However, basion-dental interval, clivus canal angle, and atlanto-occipital joint axis angle were not different between the 2 groups. Total LMD and unilateral LMD positively correlated with ADI and fracture gap. The incidence of fracture gap larger than 7 mm was statistically higher in the TAL injury group than the TAL intact group (81% vs 30%).In conclusion, total LMD > 5.9 mm or unilateral LMD > 4.3 mm suggests the presence of TAL injury in USSF of the C1 LM. The possibility of diagnostic error for TAL injury can be further reduced in USSF of the C1 LM by considering the fracture gap larger than 7 mm.

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Unilateral C1 Sagittal Split Fractures: An Unusual Entity Revisited

Cited by 5 publications

References 17 publications

Biomechanical effects of posterior lumbar interbody fusion with vertical placement of pedicle screws compared to traditional placement

Biomechanical effects of posterior lumbar interbody fusion with vertical placement of pedicle screws compared to traditional placement

Clinical and radiological outcomes of conservative treatment for unilateral sagittal split fractures of C1 lateral mass

Radiologic criteria to predict injury of the transverse atlantal ligament in unilateral sagittal split fractures of the C1 lateral mass

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