November 1993; Vol. 18; No. 15; pp. 2355-2357 Toshihiro Ando, MD and Kentaro Mimatsu, MD Department of Orthopedic Surgery, Nagoya University School of Medicine, Japan KEY POINTS FROM DAN MURPHY 1) This case of serial MRI studies shows clear evidence that lumbar discherniation can occur over a period of up to 20 months following a single traumaticinjury:A 16-year-old girl with no history of back pain, riding a motor scooter, was struckby an automobile, striking the pavement hard on her lower back.She experienced immediate low back pain.Initial exam (same day) showed no neurological signs/symptoms.Initial x-rays (same day) were normal.Initial MRI (same day) was normal.Through the entire follow-up period (20 months) she engaged in no sports of otherphysical activities.A very small signal change at L4-5 disc was observed with MRI at 2 months afterinjury.MRI at 11 months after injury showed L4-5 disc height narrowing along with anextruded disc fragment.MRI at 20 months after injury showed additional disc height reduction and thesignal intensity had decreased further. 2) MRI studies clearly showed the disc herniation to be progressing as a resultof the trauma, leading to a diagnosis of traumatic lumbar disc herniation. 3) Disc extrusion became clearly visible on MRI obtained 11 months after theaccident. It is thought that the direct impact of an external force created a ruptureof incomplete rupture of the annulus fibrosis, which represented a weak spotmechanically to release stress on the disc, leading to gradual extrusion of thenucleus pulposus. 4) It is necessary to carefully observe changes in other cases such as this one,in which disc degeneration progresses steadily for months after trauma, even whensymptoms are minor. 5) If any signs of change on MRI, patients should be repeatedly observed withcaution. COMMENTS FROM DAN MURPHY These authors are clearly advocating repeated MRI on patients with persistentsymptoms, and not to rely on the initial or early MRIs when they appear to be non-revealing. This is a 2nd study (of 3) I found doing a search for a PI attorney (plaintiff) fromSalt Lake City. The primary perspective is: It is often (essentially always) claimed by insurance defense attorneys andtheir experts that if the MRI is normal that there is no injury. This studyclearly shows that is not the case because a traumatized disc candegenerate and herniate over a period of time (months, up to 20 months). A plaintiff attorney might use such a study to ask a defense expert something like: Doctor… * After a disc is injured, can the immediate MRI be essentially normal? * After a disc is injured, can an MRI taken 2 months after injury be essentiallynormal? * After a disc is injured, can sequential MRIs, taken over a period of 20 months,show progressive disc degeneration and eventually herniation, even without anyensuing injury or physical stress? * In order for an expert to give his/her best opinion, should one not first haveobtained the best possible evidence? * Because you did not have sequential MRIs in this case, you really do not havethe best evidence as to whether this injury is responsible for the eventualdegeneration and herniation or not, do you doctor?