The $2 million auto rear ender

Feb 1, 2006 by

The case involves a two car traffic collision. The insured’s vehicle rear-ended the plaintiff’s vehicle. After the accident, the plaintiff was unable to work and eventually had  spinal surgery, which she claimed was the result of a 50 mph collision.  Her lawsuit for more than $2 million was for medical costs, and lost future earnings.  The process of evaluating her claims required two disciplines.

First, an accident reconstructionist calculated the impact speed of the insured into the claimant vehicle and the g-forces experienced.  He reviewed photographs, police reports, vehicle specifications, and the repair work orders for the two cars.  He then calculated the speeds and g-forces of the collision.  His conclusion was that the striking speed was about 10 mph.  The speed change, or Delta V to the claimant vehicle was about 7 mph. The Delta G, or force as applied to the rear of the claimant vehicle was about 11.5 G’s.

Secondly, a biomechanist used these numbers to evaluate the probability of injury from the accident.

The first step was to carefully examine the details of the accident.  In summary, the plaintiff was stopped at a red traffic light and did not see the insured until she was hit.  The insured had been slowing as he approached the red light but overestimated his stopping power and struck her car.  The plaintiff’s car did not strike the car ahead of her.  Both vehicles were driven away from the scene of the accident.  The mechanics of the accident, including the path that the plaintiff traveled within her car, were carefully analyzed and documented.

Next, the medical history of the plaintiff was examined.  She was a middle aged woman who had worked as a nurse prior to the accident.  She had no prior accidents or surgeries.  The responding officer stated in his report that at the scene of the collision she complained of soreness, but refused any medical aid.   She told him that she was okay and did not need an ambulance or medical assistance.  Later in the day her husband took her to a Community Hospital for complaints of general muscular pain.  She was examined and her back was x-rayed.  The x-rays showed no acute fractures, but revealed chronic degenerative disc disease.  She was discharged with prescriptions for muscle relaxants, pain killers, and an anti-inflammatory.

She then sought follow-up treatment from her chiropractor, Dr. 1 for continued complaints of pain.  In addition to his treatments, he referred her to Dr. 2 for an orthopedic evaluation.  Dr. 2 felt that she had sustained soft tissue injuries from the accident, and started her on physical therapy, which she continued for several months.

He then referred her for MRI examinations of her spine.  The MRI examinations confirmed the degenerative changes noted in the earlier x-rays. Dr. 2 referred her for neurological examinations to Dr. 3.  He found her neurological functions to be completely intact.  He found degenerative disc disease in both the cervical and lumbar spine.
A few months later Dr. 4, an orthopedic surgeon  examined her.  He felt that she suffered from a cervical strain and sciatica.  Following additional physical therapy, Dr. 4 prescribed cervical spine epidural injections.  Dr. 5 then examined her for pain management.  Dr. 5 also discussed possible surgical options with her.

Dr. 6 (a neurosurgeon) then examined her.  At the time of the examination, she had neck pain that radiated to her right upper extremity and lower back pain that radiated to her right lower extremity.  Dr. 6 performed a posterior lumbar interbody fusion on the plaintiff (L4-L5), which reduced her pain to pre-accident levels.

The biomechanist’s next phase was analysis: occupant motion (i.e. occupant kinematics) and the injury biomechanics of low-speed, rear-impact collisions are well documented and well understood because of numerous human volunteer studies.  In rear-impact collisions the apparent motion of the head and torso is toward the rear of the vehicle.  As her vehicle accelerated forward from the rear-end impact, the seatback and headrest moved into her.

The seatback and headrest acted to maintain the postural relationship of the driver’s spinal elements by limiting extension of the cervical and lumbar spine and by preventing differential motion between spinal segments.  In her rear-impact collision with the given delta velocity there was no potential for injury during the initial rearward movement of the occupant.

The seatback and headrest also absorbed energy, thereby limiting the forward bounce-back acceleration of the driver and the energy available to produce differential motion in cervical and lumbar spinal segments, this time in flexion.  In a rear-impact collision, the head moves into the headrest and may then rebound.  Although the peak acceleration of the head occurs as the head moves backward (in relation to the vehicle) and produces maximum deformation of the headrest, the potential for injury comes during the rebound phase.  Numerous studies demonstrate that at the speeds involved in this crash there was no potential for injury during the rebound phase.  Other injury mechanisms were evaluated and then ruled out as being inconsistent with the facts of this particular accident.

His conclusion was that she experienced delayed onset muscle soreness following the accident.  Such muscle strain, however, would have resolved without treatment.  Acute cervical or lumbar spinal trauma, or aggravation of previous spinal pathology, was absolutely inconsistent with the maximum loading that she experienced during the accident.  Her degenerative disc disease would have ended her nursing career regardless of the accident. His report referenced thirty studies that supported his opinion.

The jury agreed, and awarded the plaintiff $60,000.

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