Wednesday, March 20, 2013

Biomechanical Issues for Motor Vehicle Collisions



Biomechanical Issues for Motor Vehicle Collisions

It is important for the doctor to recognize that if a particular case goes into litigation, the insurance carrier will often hire a defense biomechanics expert, or medical expert that uses the conclusions of the biomechanists, to challenge the patient’s injuries and symptom logy, as well as the doctor’s diagnosis and treatment. The biomechanist can be an effective ally for the defense if he/she can attack the injury mechanisms and G forces (acceleration) generated during the collision, and influence a jury to believe the patient was not injured or simply had a trivial injury that would have resolved within a brief period of time with or without any treatment. These opinions are then typically reiterated by the defense medical expert, who is in agreement with the biomechanist, with the clear objective of downplaying the extent of the plaintiff’s injuries (bias) and attacking the treating doctors. In most cases the defense biomechanics expert will focus on the following issues:
               -Insufficient force to cause injury
               -Downplay the severity of injury, this giving the defense doctor basis to state that the treatment was excessive and unnecessary
               -Forces of collision are similar to those experienced in activities of daily living and therefore not responsible for post crash symptoms or injuries
               -Will often rely on limited living human volunteer testing (no subjects taken from general population) and extrapolate data to the specific patient
               -No injury mechanism
               -All post-traumatic symptoms were due to prior degenerative conditions or injuries and would have occurred at the same time frame absent the MVC

Saturday, March 16, 2013

Turyn’s Sign Lumbar Disc Disease Classification


Turyn’s Sign

Lumbar Disc Disease Classification








Variation of the lumbar disc disease classification model is as follows:

1.      Disc protrusion:
a.      Type I: Peripheral annular bulge
b.      Type II: Localized annular bulge
2.      Disc herniation:
a.      Type I: Prolapsed intervertebral disc
b.      Type II: Extruded intervertebral disc
c.      Type III: Sequestered intervertebral disc

Categories of Low Back Pain

The following are five categories of low back pain:
1.      Viscerogenic pain: Pain that originates from the kidneys, sacroiliac, pelvic lesions, and retroperitoneal tumors. This type of pain is neither aggravated by activity nor relieved by rest.
2.      Neurogenic pain: Pain commonly caused by neurofibromas, cysts, and tumors of the nerve roots in the lumbar spine.
3.      Vascular pain: Pain characterized by intermittent claudication from aneurysms and peripheral vascular disease.
4.      Spondylogenic pain: Pain directly related to the pain originating from soft tissues of the spine and sacroiliac joint.
5.      Psychogenic pain: Pain that is quite uncommon and ascribed to nonorganic causes.

Sciatica

The origin of sciatica includes the following:
1.      Prolapsed intervertebral disc pressure, infection, and traumatic sciatic neuritis, perineural fibrositis, infections and tumors of the spinal cord.
2.      Lumbosacral and sacroiliac sprain and strain, degenerating intervertebral discs, fibrositis, osteomyelitis, hip joint disease, and secondary carcinomatous deposits in bone.
3.      Nephrolithiasis, prostatic, renal, and anal disease.
4.      Toxic and metabolic disorders, conversion hysteria, and arterial insufficiency.

Procedure:
1.      When the patient is in the supine position with both lower limbs resting straight out on the table, dorsiflexion of the great tor elicits pain in the gluteal region.
2.      The sign is significant for sciatic radiculopathy.

Clinical Pearl

A straight-leg-raising test this is positive under 30 degrees reveals a large disc protrusion. The nerve root is stretched long before it would normally be. The straight-leg-raising test is most useful for identifying L5-S1 disc lesions because the pressures on the nerve root are highest at this level. During straight leg raising, L4-L5 is not as apt to give as much pain as L5-S1 because the pressure between the disc and the nerve root at L4-L5 is half that at L5-S1. Therefore the L5-S1 disc lesion gives more pain in the lower back and leg than does the L4-L5 disc lesion. No movement on the nerve root occurs until straight leg raising reaches 30 degrees. No movement on L4 occurs during a straight leg raising test. From this, the presence of Turyn’s sign indicates a large disc protrusion at the level of the L5-S1 nerve root.

Thursday, March 14, 2013

Multiple-Vehicle Collisions


                                                      Multiple-Vehicle Collisions
               




Multiple collisions, in which a vehicle is submitted to one or more successive collisions after the initial collision, are of special significance as far as the types of occupant injuries and the injury severity are concerned. One of the primary concerns for multiple impacts is the risk of the first impact resulting in the occupant being out-of-position (OOP) for the second crash. In addition, having injuries from a second impact superimposed upon injuries from the first impact may significantly alter the nature and extent of injuries, depending upon the circumstances. In some instances, the doctor will be confronted with a patient who has been involved in a multi-vehicle collision and has been requested to determine if the first or second crash was responsible for the injuries or the respective percentage of causation. The doctor’s opinion may be needed to determine apportionment for each collision. If two insurance carriers are involved, they may want to pass the blame for injuries to the other carrier. From a biomechanical perspective, multiple collisions are very challenging. Several issues that need to be considered:
               A) delta-V for first impact and the subsequent crash(s)
               B) mass ratios of the vehicles involved for each impact
               C) vehicle rotation for each crash, if occurring, and if so, how severe
               D) types of vehicles involved (i.e., SUV vs. a passenger car in a side impact). Height issues between the two vehicles and aggressive designs can result in differing injury patterns.
               E) intrusion extent into the occupant compartment for each vehicle, if any.
               F) contact point on the vehicle relative to the seating position of the occupant and proximity to the contact area, and whether the point of impact (POI) was rigid or soft. Rigid pillars and smaller structures will cause much higher acceleration levels than softer impacts or by larger objects capable of distributing loading over a larger area of the body.
               G) times of occupant acceleration. Longer impacts are better for occupants
               H) OOP issues for occupant at the time of each impact. Both impacts may have OOP issues.
               I) Second injury superimposed on first injury. Doctor needs to consider each impact with its own characteristics. For example, did each impact involve a head strike or did one impact cause inertial loading only? Need to consider the surface size and energy absorbing quality for each impact as well.
               J) Type and severity of first injury can make second impact more or less likely to cause other injuries.
               K) Patterns of injury related to vector of each crash.
               L) other human and vehicle factors.
              
               Temming and Zobel used a Volkswagen database of 1,620 occupants who suffered cervical spine injuries, concluding that about 23.5% of occupants in passenger cars were involved in at least one additional collision and 5.6% of occupants had a third impact following the initial crash. Another study found that multi-vehicle collisions occur in about 15% of total crashed, and the second collision speed has been found to be just as high as or higher than the first crash 43.2% of the time. An example is the rear-end collision in which one car is pushed into a vehicle ahead, and is struck on the side of the vehicle in the intersection, starting a chain reaction of traumatic events. Otte et al. concluded that injuries may be caused by almost all parts of the interior, due to actual impact situation and the consequent relative motion of the occupants.
               Fat et al. analyzed CCIS-UK data of 1,295 crashes looking for multiple impacts. Their study found that a secondary impact with another vehicle occurred in 22.6% of crashes and an additional 6.1% were involved in a third impact. The study concluded that there was a higher risk of occupants being seriously injured in multiple impacts, with the head having the highest frequency. The most common double impact events happened in frontal crashed followed by side impacts or side impacts followed by another side impact.

Monday, March 11, 2013

Distraction Test



Distraction Test

The complaints of patients with chronic or degenerative conditions of the cervical disc are quite different from those of patients with acute conditions. Patients with chronic conditions experience intermittent episodes of pain, discomfort, and muscle spasm. Exacerbations come from exertion. Pain and stiffness may result from weather changes or unexplained causes. Radiculopathy is not always present. Hyporeflexia, motor weakness, and sensory disturbance (especially paresthesia) are common.

1.  Delay in the onset of symptoms.  If the symptoms are not written down and documented within a few hours or days after the crash, then it is very difficult for the patient to say he/she had pain when there is no written evidence.  This can be a critical issue in a case, for example, the first doctor to note that the patient had a traumatic brain injury was made 8 to 10 months after the collision.

2.  Delay in seeing the first doctor.  Any significant delays between the date of the crash and seeing the doctor may create credibility issues for the case.  The patient needs to have a good explanation for waiting for several days to weeks for the first appointment.  There may be legitimate issues such as, some doctors have very busy schedules and may not have appointments available for several days.  The reasons for delays should be noted in the file.  The doctor or patient may have a vacation or work trip scheduled, be out of town for a medical emergency, may have an unrelated surgery that made it impossible to make an appointment, or may simply have not transportation available.

3.  There were conflicts in the history given by the patient in the records.  For example, patient stated in his deposition that he had never been involved in a crash before.  Records from 1989 indicate that the patient was involved in a rear-end crash.  The ER doctor notes that the patient did not use a seatbelt and the orthopedist noted that the patient did use a seatbelt.

4.  Little-to-no damage to vehicle.  The defense will advocate that the damage to the vehicle equals the injury potential (see Chapter 15 for crash speed thresholds for injuries).  There are generally few photographs taken of the vehicles that adequately show the extent of the damage.  Most jurors are going to see poor quality blow-ups of the vehicles or as the parts are removed for repairs.

5.  Impact forces not sufficient to cause any injury or was sufficient enough to have caused only mild muscular strain that would have healed without treatment within a few days may have occurred.  No mechanism of injury was possible in this collision.

6.  No objective findings to prove injuries.  No bruises, bleeding, lacerations, fractures, or photographic evidence of the injury to show the jury.

7.  The treatment that was provided was passive and has not been proven to work.  Patient’s condition would have been the same with or without treatment.  Exercise is the only thing that works.  Patient had only palliative benefits from the treatment.  No long-term benefits noted in file.  May look at deposition.  If patient states in the deposition that the treatment only helped for one to two weeks but the patient continued to have treatment for an additional four months. The case may have challenges.

8.  The duration of treatment was too long, was excessive, or was duplicative, and therefore is not justified from doctor’s experience.  The treatment costs were thus unreasonable for the mild nature of the injuries.  The osteopath, chiropractor, and physical therapist were doing similar things, and therefore the treatments were unnecessary.

9.  Gaps in treatment indicate that the patient did not have any pain.  That a reasonable person in pain would see a doctor is a common attack.

10.  Healing and full recovery takes two to four weeks.  This opinion is simply a hoax for most cases (see Chapter 7 for more about soft tissue healing).

11.  Every person will have full recovery following whiplash injuries.  Doctors and attorneys are to blame.  This is another hoax (see Chapter 13 for a review of prognostic studies).

12.  Patient saw too many providers, consistently self-referred himself or herself, and had a history of psychological problems.

13.  Documentation was poor.  The doctors did not note symptoms, or there are inconsistent statements made by the doctors.

14.  New injuries, including MVCs, falls, etc., or simply flared-up bending over are responsible for the problems.

15.  Prior injuries resulted in all of the problems.  The defense may attack the case by telling the jury that the injuries sustained 8 to 15 years earlier were responsible for the current pain, although there is not evidence of the patient being seen by any health providers for the past five to six years for any musculoskeletal pain.

16.  Prior pain and / or treatment for this pain within the past couple years clearly indicates that the patient’s pain was long-term and would have been present despite the crash.

17.  No justification for the amount of time off work.  May state that the typical patient is back to work within one week (see Chapter 12 for more information).

18.  The MRI scan results showing a bulging or herniated disc are also seen in the general population and are not related to the accident.  Typically, if any degeneration or spurring is noted in the radiology report, the defense medical and biomechanics expert will use that as his/her basis for that opinion using a “Natural Progression” theory.

19.  Future treatment is not needed.  The defense attorney may tell the jury in the opening statement that “Everyone knows that once the case settles the plaintiff’s pain will go away.”

20.  Conservative jurors who have a “Hollywood mentality” can make a case extremely difficult even with the best documentation, proof of bulging discs, and great doctors.  The jury may perceive the plaintiff as looking healthy and there are no photographs of blood and guts.  Some court districts are known as being very conservative, thus making it difficult to get any significant awards.  Some jurors may see that there is monetary motivation for the plaintiff.

Wednesday, March 6, 2013

Brachial Plexus Tension Test


Brachial Plexus Tension Test

Clinical Pearl

Although the brachial plexus tension test involves shoulder joint movement, it also provides maximum stretch on the brachial plexus, which affects the lower branches of the cervical spine (C5) the most. If this test is positive, the early stages of a C5 nerve root disorder may be present along with the subtle signs of a positive doorbell sign (pain that occurs at the superior scapulovertebral border and radiates with the use of deep palpation of the C5 segment) and pain in the deltoid area. The deltoid pain is often misconstrued as an articular problem of the shoulder.


Dejerine’s Sign

Clinical Pearl

Patients with radicular symptoms and pronounced Dejerine’s sign, especially if it is in the lumbar spine, should be told to bend the knees and lean into a wall during a cough or sneeze. This maneuver reduces intradiscal pressure and minimizes the effect of the cough or sneeze on the nerve root. A more worrisome situation is the sudden, unexpected absence of Dejerine’s sign when all other clinical findings indicate an active nerve root compression. The loss of the sign indicates fragmentation of the disc with momentary decompression of the nerve.

Thursday, February 28, 2013

The Cervical Spine

 The Cervical Spine



Axioms of Cervical Spine Assessment
1.      Cervical spine syndromes are extremely common and are probably the fourth most common cause of pain.
2.      At any given time, 9% of men and 12% of women have neck pain with or without arm and hand pain, and 35% of the population can remember having had neck pain at some time.
3.      The cervical spine is the origin of a large proportion of shoulder, elbow, hand, and wrist disorders.
4.      Most people who develop pain in the neck do not seek medical attention because they regard such pain as a part of life, so they simply wait for it to disappear.

Saturday, February 23, 2013

Disability and Handicap


Disability and Handicap

Disability is a present when a tissue, organ, or system cannot function adequately. A handicap exists when disability interferes with a patient’s daily activities or social/occupational performance. A marked disability does not necessarily cause a handicap. Conversely, minor disability may produce a major handicap. Both conditions require separate assessment. Patients’ perception of their problems will be molded by their adaptation to the depreciated tissue as well as their aspirations for recovery.

Assessing Disability

An aid in assessing the more important aspects of disability is the PILS mnemonic, which considers four issues:

1.       P Preventable causes of disability (e.g., falls, direct trauma)
2.      I Independence (e.g., self-care)
3.      L Lifestyle (roles, goals)
4.      S Social factors (e.g., family, friends, shelter)


Functional Assessment

A complete functional assessment includes evaluation of the following:
1.      Self-care: ability to wash, bath, attend to toilet needs, dress, cook, and feed oneself
2.      Mobility: ability to stand, transfer, walk, negotiate stairs, drive, and use public transportation
3.      Lifestyle: nature of occupation, work capacity, and Social Security benefits