Search PubMed⌕ Search

PubMed · 8326430

Distal locking screw insertion using a cannulated drill bit: technical note.

Abstract

A modified freehand method using a cannulated drill bit for the insertion of distal locking screws for interlocking intramedullary nails is described. It should be useful to introduce surgeons to interlocking and to aid those who are not comfortable with the freehand method.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

E F Barrick. 1993. Distal locking screw insertion using a cannulated drill bit: technical note.. https://doi.org/10.1097/00005131-199306000-00009

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

A biomechanical assessment of infra-laminar hooks as an alternative to supra-laminar hooks in thoracolumbar fixation.

STUDY DESIGN: Biomechanical study, using human cadaveric spines, of two types of posterior fixation in the thoracolumbar spine. OBJECTIVES: To compare fixation in the thoracolumbar spine using pedicle screws combined with infra-laminar hooks (at both the cranial and caudal ends of the same vertebra) with fixation using pedicle screws alone. SUMMARY OF BACKGROUND DATA: The standard method of using laminar hooks is to place supra-laminar hooks at the level above the vertebra being fixed by the cranial pedicle screws, and infra-laminar hooks at the level of the vertebra receiving the caudal pedicle screws. However, using this method, a single normal motion segment is killed. In the proposed technique, infra-laminar hooks will be used at the same level as the cranial pedicle screws, thus sparing the superior adjacent segment. METHODS: PEDICLE SCREW LOOSENING TEST: Nine vertebrae (T9-L2) had pedicle screws inserted into both pedicles. On one side, the pedicle screw was connected to a fixation rod, while on the other side the pedicle screw was combined with an infra-laminar hook and connected to a rod. The rod on one side was then pushed with increasing force until loosening of the screw. The same test was repeated on the other rod until loosening of the screw. The reverse test (i.e., pulling until loosening) was done in a similar manner on another nine vertebrae. BIOMECHANICAL STIFFNESS TEST: Eight spines (T12-L2) were biomechanically tested in: axial compression, flexion, extension, left and right lateral bending, and left and right axial torsion. This sequence was applied to: 1) the intact spine; 2) after applying pedicle screws and infra-laminar hooks with rods to the destabilized spine; and 3) after removal of the hooks (with the pedicle screw and rods still inserted). From the load-deformation curves obtained, stiffness values were calculated. RESULTS: PEDICLE SCREW LOOSENING TEST: The pedicle screw loosening tests showed that a pedicle screw combined with an infra-laminar hook offers significantly greater fixation strength as compared to a pedicle screw alone. Biomechanical stiffness test. Fixation by pedicle screws combined with infra-laminar hooks, placed on the vertebra fixed by pedicle screws at both the cranial and caudal ends, offered a stiffer construct as compared to fixation by pedicle screws alone. CONCLUSIONS: This method offers a firm construct without sacrificing a normal motion segment.

Bone Screws↗

Placement of percutaneous pedicle screws without imaging guidance.

Pedicle screw (PS) instrumentation provides an exceptionally rigid construct to promote fusion in cases of spinal trauma and degenerative disease. Although the safety of traditional open techniques for PS placement has been well documented, there are no large series in the literature in which the safety of percutaneously placed PSs has been examined. Because the advantages of minimally invasive spine surgery are becoming more widely recognized, especially in regard to the lessening of morbidity caused by pain and blood loss, there will be a greater demand for spine surgeons to place PSs percutaneously. During a 2-year period, the authors placed 287 PSs percutaneously with the aid of intraoperative fluoroscopy. Only one of these screws was later found to have breached the spinal canal, yielding a breach rate of 0.35% for percutaneously placed PSs (one of 287).

Bone Screws↗

Percutaneous placement of posterior cervical screws using three-dimensional fluoroscopy.

STUDY DESIGN: The placement of percutaneous posterior cervical screws using three-dimensional fluoroscopic guidance was performed in intact human cadaver specimens. OBJECTIVES: To determine the accuracy and feasibility of placing entirely percutaneous posterior cervical screws using a novel form of spinal image guidance. SUMMARY OF BACKGROUND DATA: Conventional image guidance has been shown to increase the accuracy of many open cervical instrumentation procedures. There are presently no published studies reporting this novel method for guiding the percutaneous placement of posterior cervical screws. METHODS: An isocentric C-arm was used to obtain CT images of three intact cadaver specimens. A percutaneous dynamic reference array was attached to the C2 spinous process of each specimen. Light-emitting diodes attached to the C-arm were tracked with an electro-optical camera. The image data set was then transferred to the image-guided workstation, which performed an automated registration. Using the workstation, trajectories were planned for bilateral C1-C2 transarticular, C3-C6 lateral mass, and C7 pedicle screw placement. Through 1.5-cm incisions, a drill guide fitted with light-emitting diodes was used for sequential, image-guided drilling, tapping, and placement of cannulated 4.0 mm screws at each level. Postprocedure, thin-cut CT scanning was used to determine the accuracy of screw placement. RESULTS: A total of 41 of 42 percutaneous screws (97.6%) were accurately placed. All of the transarticular atlantoaxial and subaxial lateral mass screws showed no evidence of foramen transversarium, neural foramen, or facet joint violation. One of the C7 pedicle screws had a minor cortical wall violation. CONCLUSION: This study demonstrates the feasibility of placing percutaneous posterior cervical screws. Three-dimensional fluoroscopy appears to enable highly accurate, percutaneous three-dimensional cervical spine navigation.

Bone Screws↗