Considerations for the Use of C7 Crossing Laminar Screws in Subaxial and Cervicothoracic Instrumentation

Abstract

N/A.

Use and modifications of cervical and upper thoracic laminar screws in posterior stabilization

“…No new screw It has been demonstrated that the technique provided comparable stability and fixation in terms of insertional torque, pullout strength, and resistance to flexion and extension, but there may be a little less resistance to lateral bending at the C2 level (2,5,6,10,18). Ilgenfritz et al found in a biomechanical cadaveric study that C7 laminar screws were as strong as C7 pedicle screws and significantly stronger than C2 laminar screws (14). Similarly in our study, it was found that the C7 screws were stronger and revision was required for C2 screws.…”

“…In the radiological study by Saetia and Phankhonksab (27), 79% of adults had C2 lamina with an inner transverse diameter larger than 3.5 mm allowing screw placement. Ilgenfritz et al reported in a radiological study again that the majority of C7 laminae were suitable for the placement of bilateral laminar screws (14). Hu et al reported that most T1 to T3 segments had adequate laminar height and width to place bilateral laminar screws in adults (12).…”

Posterior Subaxial Cervical Spine Screw Fixation: A Review of Techniques

“…14 The subaxial cervical vertebrae (C3 to C7) have similar anatomical characteristics. 10 - 12 The spinous processes are generally bifid from C3 to C5, and becomes either bifid (47.9%) or monofid (47.9%) at C6, and usually monofid at C7 (99.2%). 15 The C7 vertebra, also known as the vertebra prominens , is the largest cervical vertebra and its spinous process is easily palpable.…”

“…Ilgenfritz et al 12 performed a radiographical and biomechanical study to evaluate the use of C7 laminar screws. Seventy-two patients had a CT scan to measure the thickness, length and spinolaminar angle of the lamina.…”

“… 6 - 9 The most commonly used screw fixation techniques of the posterior subaxial cervical spine include lateral mass, pedicle, intralaminar, and transfacet screws. 8 - 12 …”