Reasonable2012

Hi Dr. Corenman. Appreciate your thoughtful response.

The crash was quite violent in terms of acceleration/deceleration forces. My moving vehicle was brought from 25-30mph to 0mph in about six inches. The forces from this resolved to a powerful jerk backwards on my lower body through the seat belt and a powerful jerk forward to the upper body by virtue of its momentum. Simultaneously, the vehicle was pushed sideways about ten feet and so there were similar force vectors with the upper body tugged to the right by its momentum and the lower body tugged to the left by the seat belt.

It seems to me that a cartilagenous or weak boney structure such as the pars could be damaged by such forces. But maybe that is not the necessary level of forces. My 2004 MRI of the lower back does have a couple of hints that spondylolysis *to a mild degree* may have been present at that time. There was “posterior wedging” of the L5 vertebrae. The neural foramina “keyhole” structure as seen in T2 Sagital off-midline image, was at an angle of 109 degrees relative to the horizontal lower edge of the vertebrae (when it should have been closer to 90 degrees, like the vertebrae above it).

So, as you suggest, possibly there was some congenital predisposition to the spondylolysis and possibly it had already occurred as of 2004 to a limited degree. I did not have acute pain in the lower back. There was mild stenosis at that time and the L5-S1 disk was well hydrated.

The 2012 MRI, taken after the crash, documents the same degree of posterior wedging but the “keyhole” angle is now (on the worst side, there is a little asymmetry between the two) at 129 degrees. There now is about 17% spondylolisthesis (zero in 2004). The stenosis is moderate/severe and the disk is entirely degenerated in appearance. This is about 1.5 years after the crash.

So, to me, it seems reasonable to conclude that the spondylolysis was exacerbated by the forces, and that this pannus tear occurred as a result of the crash. This likely led to the 17% spondylolisthesis, the stenosis, and the disk degeneration.

1. Let me ask you this? How likely is it that an existing spondylolysis could be exacerbated without the acute pain of a fresh fracture? Same question for the torn pannus…could it be torn without acute pain (or pain that could be masked with meds)?

2. Can you clarify your response about rate of disk degeneration? In your first paragraph you indicate 3-6 months or more as the time it takes a disk to show degeneration after a car crash. In Paragraph 4 you indicate 10-15 years or more to go from pars fracture to degeneration.

It would seem to me that in your example of a car crash ejection and a fresh pars fracture, that you could see disk degeneration in 3-6 months. Are you merely saying that the typical scenario is for the pars fracture to occur in childhood and the subsequent pannus tear, spondylolisthesis, stenosis, and disk degeneration to occur many years later? (By the way, is there a name for this whole process of degeneration: pars fracture => pannus tear => spondylolisthesis => stenosis => disk degeneration => miserable life?)

3. It does sound like what you are saying is that what I experienced is common, but with the pannus tear kicking off the whole degenerative process rather than the spondylolysis (which was preexisting but to a lesser degree). My very first, and mild symptoms, started after about 8 weeks. They were starting to get problematic at about 4 months later. By 11 months later they were substantially life changing, affecting day-to-day activities. Would you agree that this is an accurate understanding of the process and a common scenario?

4. Not a question, just an observation. There is no social awareness of this whole lower back degenerative issue and how a car crash or sports injury can interact with it. We commonly know to watch for whiplash injuries, but not this. This seems to be the whole KEY for avoiding the bulk of back injuries in life. From a mechanical analysis, this is the weak point in the design isn’t it? It seems this needs to be taught in schools so people truly understand the motions and forces to avoid. Lower back injuries are crippling and miserable, and they seem to me largely AVOIDABLE once one truly understands the back’s “achille’s heel”.

I am left wondering, if a CT scan had been done at the time of the crash, if maybe the substantial 129 degree spondylolysis would have been detected, and the disk was still well-hydrated. Maybe it could have been repaired at that time, and maybe I could have kept my quality of life. One of those nagging what-ifs…