Spinal stabilization implant and method of application

Abstract

Vertebra bodies in the human spine are stabilized through the use of minimally invasive surgery for the implantation of an elongate implant plate assembly having spaced first and second screw receiving socket elements which are configured for respective attachment to first and second spaced vertebra with the aid of bone fixation screws and these elements are slidably received with respect to each other for adjustably changing the distance between the screw receiving socket elements. A lock assembly is also provided for selectively locking the first and second screw receiving elements from further relative sliding. An elongate insertion tool is releaseably secured to the plate assembly, and the insertion tool is configured for manipulating the plate assembly as a whole and for remotely manipulating the screw receiving socket elements for adjusting the distance therebetween. The plate assembly is inserted through an incision and manipulated and advanced with the insertion tool to provide minimally invasive insertion, and after fixation of the implant assembly with bone fixation screws is further utilized by remote manipulation to adjust the degree of compression on the vertebrae, and thereafter the implant is locked in position to prevent further relative movement between the screw receiving elements of the plate assembly.

Description

CROSS REFERENCE [0001] This is a continuation-in-part of U.S. patent application Ser. No. 10 / 615,196, filed Jul. 7, 2003 for SPINAL STABILIZATION IMPLANT AND METHOD OF APPLICATION.FIELD OF THE INVENTION [0002] The present invention relates generally to fixation systems for osteosynthesis of the spine, and more particularly, it pertains to a spinal implant system and a surgical procedure for inserting and applying the implant. BACKGROUND OF THE INVENTION [0003] Spinal surgery on the lumbar and thoracic spines have classically been open operations, meaning that the instrumentation used is placed through an incision that exposes all of the spine to be instrumented, as well as a portion of spine above and below the area to be instrumented due to the need for proper visualization. This extensive exposure disrupts a considerable amount of tissue, particularly the lumbar paraspinal musculature which needs to be stripped off the vertebra bones for exposure. This stripping leads to muscle da...

AI Technical Summary

Benefits of technology

[0008] Cap buttress nuts are threadably received in each of the socket elements over the screw heads for engaging and covering the screw heads. The nuts are also provided with bottom protuberances for engaging the screw heads as a lock to prevent accidental dislodgement or backing off of the screws.

[0009] The system of the present invention further envisions the use of an insertion tool or instrument for inserting the implant plate assembly of the present invention as just described or for inserting an implant plate assembly of different design. When using the insertion tool of the present invention, the distal end of the plate assembly is provided with a leading transverse edge which is tapered in order to provide a self-cutting action during insertion by minimally invasive techniques and also to provide a profile which permits the plate assembly to nestle next to a facet joint without impeding the joint's functional movement. In addition, the plate assembly may be longitudinally curved to mate a specific lordotic curve of the spine.

Problems solved by technology

This extensive exposure disrupts a considerable amount of tissue, particularly the lumbar paraspinal musculature which needs to be stripped off the vertebra bones for exposure.

This stripping leads to muscle damage directly caused by either electrical cautery or manual cutting or indirectly by interruption of vascular supply to the muscle due to coagulation or cutting of vessels, and caused also by embarrassment of the vascular supply during the course of surgery due to compression by retractors on the muscle which are required to maintain exposure.

In addition, spinal implants can impact upon the facet joints of the spine, particularly the upper most pair of pedicle screws, which can cause pain or dysfunction of the involved joint.

The present day surgical approach therefore has added to patient morbidity due to the extent of the surgical exposure, tissue damage done primarily to the posterior longitudinal musculature of the spine during the exposure, blood loss and risk of infection.

Large open operations also tend to be the cause of significant postoperative pain and disability.

Accordingly, these issues lead to longer hospital stays, higher postoperative complications, such as phlebitis and pneumonia brought on by immobility, and greater consumption of postoperative medications with their resultant side affects.

Also, interference by metal implants of the normal function of the rostral facet joints has been implicated in the early degeneration of these joints, as well as pain and disability, all which could lead to other more involved surgeries.

Images