My Spine - Lumbar
It is usually assumed that bone growth takes place from six weeks onward and significant bone growth usually only occurs within three to six months . If it takes longer than a year , then it is called a delayed union and if it takes longer than two years one must assume that the fusion is unlikely to unite .
There are a variety of pedicle screw systems and spacer systems available and they are usually detailed in the web pages of the manufacturer . You may want to ask your specialist about the name of the spacer or the pedicle screws that are likely to be used for this purpose . The implants do not constitute a fusion by themselves , because they contain no bone , which always has to be added . The instrumentation purely constitutes a mechanical device which allows fusion to take place in a higher percentage of patients , while at the same time the vertebrae are held in the best position for healing and function of the lumbar spine . The operation is performed from the back , through an incision over the lumbar spine , which is slowly deepened to expose the posterior aspects of the lumbar spine .
Occasionally no decompression of the nerves or approach to the disc area is necessary , in which case the fusion can be done between the transverse processes , the laminae or the spinous processes .
If decompression of the nerves are required , removal of damaged disc or even more extensive removal of the spinous processes and laminae may be needed . In this case the nerves and the spinous dural sleeve ( the membrane that contains the nerves ) will form part of the operating field . In these cases the bone transplant has to be placed on and in-between the transverse processes on the side of the spinal canal .
The approach from the back is also necessary for the posterior lumbar interbody fusion and for the transforaminal interbody fusion . In the case of a transforaminal interbody fusion , the disc space is accessed from the space available on the outer side of the nerve roots and dural sleeve , underneath the facet joint on that side .
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