Method and instruments for percutaneous arthroscopic disc removal, bone biopsy and fixation of the vertebral
First Claim
1. A cannula assembly for use in arthroscopic spinal surgery comprising a cannula having a wall of uniform thickness, the wall defining a cylindrical inner passage having an oval cross section, and an obturator located within said cylindrical inner passage, the obturator having a cylindrical outer wall with an oval cross-section and closely fitting the cylindrical inner passage of the cannula.
2 Assignments
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Accused Products
Abstract
The insertion points for guide pins used in percutaneous vertebral fixation by pedicle screw are determined by establishing an approach path on a CT image, measuring on the CT image the distance from the intersection of the approach path and the skin of the patient'"'"'s back to the patient'"'"'s midline, and marking off the corresponding distance while visualizing the patient by anteroposterior fluoroscopy. An longitudinally expansible pedicle screw comprises a shaft with bone-engaging threads on a distal portion, machine screw threads on a proximal portion, and a tubular extension having wrench-engageable holes on a proximal face, and internal threads engaging the machine screw threads on the proximal portion of the shaft. An oval cannula accommodates an arthroscope and forceps simultaneously for intervertebral disc surgery.
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Citations
13 Claims
- 1. A cannula assembly for use in arthroscopic spinal surgery comprising a cannula having a wall of uniform thickness, the wall defining a cylindrical inner passage having an oval cross section, and an obturator located within said cylindrical inner passage, the obturator having a cylindrical outer wall with an oval cross-section and closely fitting the cylindrical inner passage of the cannula.
- 4. A method of spinal surgery comprising the steps of introducing percutaneously through the back of a patient a cannula assembly comprising a cannula having a wall of uniform thickness, the wall defining a cylindrical inner passage having an oval cross section, and an obturator located within said cylindrical inner passage, the obturator having a cylindrical outer wall with an oval cross-section and closely fitting the cylindrical inner passage of the cannula, removing the obturator, and introducing at least two instruments through the cannula whereby said at least two instruments extend through the cannula simultaneously.
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6. A method of spinal surgery comprising the steps of:
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inserting an elongated, hollow sleeve percutaneously toward an intervertebral disc of a patient posterolaterally, while the sleeve has an obturator extending through it;
removing the obturator from the sleeve, while leaving the sleeve in place;
passing over the sleeve an assembly comprising a cannula having an lumen with an oval cross-section and an obturator having an oval cross-section conforming to the lumen of the cannula, the obturator with the oval cross-section having a longitudinal passage for receiving the sleeve;
removing the obturator having the oval cross-section from the cannula, while leaving the cannula in place. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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Specification