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3/19/2015 in Blog Categories, News

Prescription pain medication overuse and abuse is and has been a national problem for many years now.  We have previously written about the issue in Second Opinions.  Among the common suggestions that experts make for curbing the problem are more stringent dosing guidelines, creation of and active prescriber participation in state prescription drug monitoring programs, and greater provider education about the problem.  Recent data from Washington State shows how effective these interventions can be.  Medical News Today reports on a study published in the American Journal of Public Health that while prescription opioid death rates have remained steady for the nation as a whole from 2008 to 2012, Washington State saw a 28% decline.  The article specifically notes that:

New state laws on prescription opioid use, including one that mandated the adoption of new dosing guidelines; a statewide Prescription Drug Monitoring Program; and telemedicine and on-line programs for health care providers have all been key to the turnaround.

Provider participation in telemedicine online programs was seen as a key factor in educating providers on appropriate dosing, medication changes, and dangerous drug interactions to avoid.  The electronic programs also have the advantage of allowing providers to discuss difficult cases with specialists to help craft solutions that avoid dangerous opioid use, decrease patient suffering, and preserve the doctor-patient relationship.

Here in the Midwest, we should demand that our clinicians, university medical centers, and legislators work together to craft an effective program to curb prescription pain medication overuse and abuse.  The Washington State example demonstrates that substantial, cost-effective improvement in prescription pain medication practices can be achieved when all concerned parties come to the table and work together.    And for those of us in the medico-legal world, curbing prescription pain medication overuse and abuse would be a welcome development in helping control the monetary and human costs of many claims.

Chronic pain devastates sufferers and those close to them.  When it arises in the context of a worker’s compensation or personal injury claim, chronic pain complicates claims management and invariably increases costs, making a satisfactory resolution to all parties difficult to achieve.  The most heartbreaking context in which chronic pain arises is, however, military veterans injured in combat.  Unfortunately, veterans returning from Iraq or Afghanistan suffer higher rates of chronic pain than veterans of any other U.S. Military conflict.  The good news is that the VA is aggressively researching the problem and recently made some headway (that could alter the standard treatment protocol for all chronic pain sufferers, regardless of etiology).

VA researchers published the results from the ESCAPE trial (which stands for “Evaluation of Stepped Care for Chronic Pain”) in which they found that a specialized stepped care program resulted in participants reporting a “decrease in pain severity and 30 percent improvement in pain-related disability.”  The results are significant because “we know that medications alone are only modestly successful in helping [chronic pain sufferers]” and that “current pain treatments haven’t made much of a dent,” according to Dr. Matthew Bair, who led the study.

The stepped program involved an initial 12 weeks of treatment with analgesic medication and self-management using such strategies as relaxation techniques.  The second step involved 12 weeks of cognitive behavioral therapy.  The second step helped participants “counter maladaptive thought” and to learn what activities they could substitute for pre-deployment activities to decrease pain and remain physically active.  This second phase would seem critical in the claims context where the greatest challenge is often simply overcoming the disability mindset, or turning the ingrained and almost pathological attitude of “I can’t” to “I can.”  In many cases, the issue is not that the chronic pain sufferer cannot perform an activity so much as it is that they convince themselves that they cannot before even attempting the activity.  The exciting thing about the study results and using targeted cognitive behavioral therapy in general is that it can help reorient the way chronic pain sufferers view activity in general.  Just because an injured worker can no longer train for and participate in marathons due to chronic low back pain does not mean that she cannot complete an 8-hour day as a delivery driver.  If cognitive behavioral therapy can help chronic pain sufferers to start looking at the world from the psychological perspective of “I can,” it would seem to go a long way toward improving both the lives of chronic pain sufferers and the outcomes of chronic pain claims.

The ESCAPE study is an exciting development in managing chronic pain patients.  Given the difficulty of managing chronic pain claims and the explosion in prescription opioid drug abuse related to treatment of chronic pain, it will be worth following the ESCAPE study to see if its results can be replicated.  Even a 30 percent reduction in disability level would likely be significant in a chronic pain claim and could easily represent the difference between partial impairment (and a return to work) and total disability.

Perhaps the most difficult challenge in orthopedics is articular cartilage.  You know, the white, pearlescent stuff that covers our joints and makes them operate smoothly and without pain (before arthritis sets in, that is).  And why is articular cartilage so difficult?  Well, it’s pretty simple:  we can’t regrow it when it breaks down and wears away.  Hence, the only options for treating worn articular cartilage or osteoarthritis are, once the pain and dysfunction become unbearable, to fuse the worn joint or to replace it with artificial components.  Despite advances in orthopedic components and surgical techniques, joint replacement is a suboptimal option for treating worn articular cartilage.  Fusion is even less optimal, the point of joints being articulation (or motion).

If we could figure out a way to regrow articular cartilage, calling it game-changing would be an understatement.  It would be revolutionary, especially for those in the worker’s compensation world where countless musculoskeletal injury claims involve allegations that work injuries or occupational exposure caused or worsened osteoarthritis.  Can you imagine a world where a claimant with debilitating knee pain goes to the doctor and rather than walking out with a knee replacement, the claimant goes to a gene therapist who treats the knee by growing new articular cartilage?  No surgery, no infection, no rehab, no disability, just a new knee. 

Turns out this dream is closer to reality than you might think.  Researchers in Manchester, England recently published research in which they used embryonic stem cells to regrow articular cartilage in the damaged knee joints of rats.  Remarkably, "[a]fter 12 weeks, the cartilage surface was smooth and similar in appearance to normal cartilage.”  In contrast to earlier efforts which produced abnormal and disorganized tissue, including tumors, the Manchester scientists were able to grow wholly normal, functioning cartilage in the rats’ knee joints.

These findings from the Manchester study are exciting (almost beyond exciting, truth be told).  The research is worth monitoring as it advances toward testing in human subjects, which is still probably several years away.  Nevertheless, this development gives us a glimpse of a potentially arthritis-free future.  Imagine that.

2/20/2015 in Blog Categories, News

Test your own line of reasoning for internal consistency.

Much of the point of Brewer’s preceding rules or decision heuristics was to remove assumptions and emotion out of the claims evaluation process.  This step is where we put the prior steps to work for us to evaluate whether we have in fact successfully analyzed the claim before us in an unbiased and logical fashion. 

Let us assume that we are analyzing a claim involving an acute foot injury followed by years of occupational exposure in an obese, 46-year-old, female claimant.  When the claimant was 37, she suffered a calcaneal fracture while on the job.  She is employed as an assembler doing light work, but stands for the duration of her shift.  She was not issued final restrictions after reaching an end of healing following the first injury, but was issued a 15% PPD rating based on loss of motion.  The employer did not offer any accommodations to limit the amount of standing the claimant would have to do, but the claimant never requested an accommodation or complained about standing too much.  The claimant subsequently developed arthritis and is scheduled to undergo a subtalar fusion.  Medical opinions support three possible causes for the claimant’s current condition and the need for the fusion:

  1. The arthritis is related to the claimant’s age and body habitus and bears no relationship to the calcaneal fracture or the subsequent workplace exposure;
  2. The arthritis is wholly related to the calcaneal fracture, is a normal sequelae of that type of injury, and the subsequent occupational exposure was not a material contributory causative factor in the onset or progression of the arthritis;
  3. The arthritis is posttraumatic and the subsequent occupational exposure was a material contributory causative factor in the progression of the arthritis (causing it to progress faster than it otherwise would have).

In our case, we represent the carrier on the risk for the subsequent occupational exposure date of injury.  Our IME doctor concluded that the claimant developed the arthritis due to her age and weight and supports his conclusion by arguing that the claimant would have become symptomatic much sooner if the arthritis were posttraumatic.  The IME doctor for the carrier on the risk for the acute fracture date of injury concluded that the arthritis is posttraumatic but that the subsequent period of occupational exposure caused the arthritis to progress faster than it otherwise would have.  Finally, the treating surgeon concluded that the acute fracture is the sole cause of the arthritis and the need for the surgery. 

During the course of our investigation we learned several things:

  1. The claimant’s non-injured foot is asymptomatic;
  2. The claimant dislocated the same ankle while sliding into third base during a high school softball game when she was 16.  The dislocated ankle was manually reduced and treated non-surgically with casting then physical therapy;
  3. The claimant works from 7:00 to 3:30 and has two 15 minute breaks and a 30 minute lunch.  The employer admits that generally the claimant and other assemblers stand for the balance of each day unless they are in a meeting.  Production meetings are held Mondays at 7:00 and last 15-20 minutes.  Otherwise assemblers are infrequently in meeting (less than once per month). 
  4. 9 months before the occupational date of injury the employer hired a new production supervisor.  In general, the assemblers do not like the new supervisor and several, including the claimant, complained to human resources about his conduct. 
  5. The calcaneal fracture and the current subtalar fusion are the only worker’s compensation claims the claimant has made.
  6. Both insurance carriers took recorded statements and the claimant consistently describes the injury occurring gradually, over a period of a few months, progression until it became too painful to ignore at which time she sought treatment with the orthopedist who treated her original fracture.
  7. The original calcaneal fracture was displaced and treated surgically with open reduction and internal fixation.
  8. The claimant reported that she does not wear high heels or other non-supporting shoes but instead generally wears running shoes when she is not a work.

Based on the information obtained in the investigation, we developed a litigation plan and completed our investigation.  Now we have our litigation plan in place and are preparing to roundtable the claim with our supervisor.  Before heading to the roundtable, we have decided to run through the claim again to judge whether we are still comfortable enough with our analysis to present and defend it at the claims roundtable.

We reached the following conclusions about the claim:

  1. An ALJ is likely to find the current condition to be work-related because the uninjured ankle is asymptomatic.
  2. An ALJ is more likely to find the original fracture is the appropriate date of injury than the occupational exposure date because the treating orthopedist on both injuries concluded the subsequent occupational exposure did not cause the onset or progression of the condition.

To prepare, we need to analyze our conclusions to see if they are internally consistent.  First, we concluded that the injury is likely to be deemed work-related.  In examining the claims file, two strong facts support our conclusion.  One, the employee’s uninjured foot shows no evidence of arthritis.  This is significant because the claimant’s occupation stresses the subtalar joints of both feet equally (or nearly so).  Hence, if the arthritis were idiopathic we would expect to see the arthritis in both subtalar joints.  Two, subtalar arthritis is a well-known and relatively common complication of calcaneal fractures.

Second, we concluded that the ALJ is more likely to conclude that the original fracture is the appropriate date of injury for the claimant’s current condition.  Our basis for concluding this is that the treating physician who treated the original injury and the current condition is the same; therefore, he has had the best chance to observe the claimant over time which renders his opinion most credible.  This is not as solid a position as the first one is.  In a sense, the argument is a non sequitur because it does not necessarily logically follow that the treating physician is better able to determine causation based on familiarity with employee’s condition over time.  In making this argument, we have at least one unstated premise that needs to be articulated and explored before we can determine if the argument is in fact internally consistent and valid.  The unspoken premise is a common one in worker’s compensation:  all things being equal, ALJs consider treating physicians to be more credible than IME physicians.  As far as I know, this assumption is based on experience and anecdote and not actual objective data.  Hence, we need to be cautious in applying the assumption to our argument and should not consider it necessarily to be dispositive.  The reason for our caution is that the assumption is based on the overarching view that most ALJs will, all things being equal, apply the Worker’s Compensation Act liberally and grant benefits to employees making claims.  If this view is true, and at least it is reinforced by statute and state Supreme Court pronouncements, then it actually may weaken our assumption that an ALJ will find the treating physician most credible in this case.  The reason is that if an ALJ were to find the treating physician most credible, the employee would be stuck with benefits at a considerably lower rate than if the ALJ found the IME doctor for the original date of injury to be most credible.  Remember:  the IME doctor for the original date of injury insurance carrier finds the claim is work-related and his opinion establishes a date of injury 9 years later, with the corresponding increase in the temporary total disability and permanent partial disability rates that would obtain.  If the primary motivating factor of an ALJ in a close case is giving benefits to a claimant then it is reasonable to assume that the ALJ will also be motivated to give a claimant the highest benefit rate when there is a credible opinion allowing her to do so.  Thus, we may wish to adjust our opinion and note that the date of injury is likely to be a closer call than we at first posited.

Obviously this is simplistic and something of an exaggeration intended for illustrative purposes.  Presumably, we would have considered the problematic assumptions about the date of injury as soon as we had all the relevant medical opinions.  Nevertheless, the example serves a purpose:  when evaluating a claim, you must test the line of reasons that led you to the conclusions you reached for internal consistency.  In doing so, you will stand the best chance of discovering non sequiturs and other logical reasoning problems or errors that may cast doubt on the validity and strength of the conclusions you reached.

Reason #1:  Employers shall not use doctors “employed on a regular basis by the employer” when seeking FMLA second opinions.  We have a large number of doctors to choose from and can track how many times you have used the same doctor. 

Medical Systems, Inc., we’re not just for worker’s compensation any more.

2/10/2015 in Blog Categories, News

The University of Texas Southwestern Medical Center released information critical to the success of cardiopulmonary resuscitation (more commonly referred to as “CPR”) efforts.  Specifically, medical researchers reviewed research and found that persons applying chest compressions to those in cardiac arrest often compress the chest too deeply and too rapidly.  Researchers say there is a “sweet spot” between the depth of compressions and the rate of compressions that optimizes the chances for a patient’s survival.  For chest compressions to have the best chance of working, they need to be performed to a depth of between 5 and 5.5 centimeters (about two inches) and at a rate of between 100-120 compressions per minute.  The researchers found that compressing the chest greater than 5.5 inches reduces the likelihood of survival and speculate that such deep compressions probably cause injury to the patient which counteracts the resuscitative effects.  In addition, researchers found that many responders perform chest compressions at rates of about 140 compressions per minute, which is too fast and reduces the effectiveness of the resuscitation attempt.  To achieve the right rate of compression, researchers noted that timing the compressions to the beat of “Row, Row, Row Your Boat” is effective and used by many well-trained first responders.

First responders and others trained in CPR should be aware of this new information.  Chest compressions that are too soft are ineffective as are compressions that are too hard.  Ditto compressions that are too slow or too fast.  Instead, chest compressions need to be just right. Apparently Goldilocks was on to something.

Medical News Today reports on a significant new study (fee or subscription required) of what causes episodes of acute low back pain.  Critically, the study’s authors concluded that most physical and psychosocial triggers of acute low back pain can be modified.  Per Medical News Today, some of the findings include:

  • [C]arrying out manual tasks involving awkward postures increases the risk of triggering acute low back pain by eight times;
  • [F]atigue and being distracted can also significantly increase the risk of acute low back pain;
  • [T]he odds of a new back pain episode was nearly 3 times higher chance following moderate to vigorous physical activity; and
  • [T]he odds of a new back pain episode was to a 25 times higher chance after being distracted during an activity.

Unusually, the study “also found that age was a factor in triggering back pain when lifting heavy loads - with younger people being significantly more likely to suffer an episode of acute low back pain after such activity than older people.”  This certainly will be counterintuitive for claims administrators and attorneys in the worker’s compensation field as conventional wisdom suggests older age is directly proportional to low back injuries rather than the inverse as was found in the study.  Regardless, the most important thing is to utilize knowledge from the study to reduce episodes of acute low back pain in the workplace.  Manuela Ferreira, lead author stated the matter succinctly:

Our findings enhance knowledge of low back pain triggers and will assist the development of new prevention programs that can reduce suffering from this potentially disabling condition.

What is it about shoulders?  They seem to cause an inordinate amount of problems, especially when the rotator cuff is involved.  And invariably, there is a question as to whether a shoulder claim involves an acute injury, an acute aggravation of a preexisting condition, an occupational injury, or the mere manifestation of a preexisting condition.  One of the biggest challenges in claims is determining whether and to what extent a shoulder condition is work-related.  Unfortunately, this task is often difficult for physicians too.

The hallmark of an acute rotator cuff injury is an asymptomatic shoulder, a discernible traumatic event, and immediate pain and weakness.  Unfortunately, this type of presentation accounts for less than 10% of all rotator cuff tears according to some literature.  In addition, the medical literature suggests that acute rotator cuff tears are underdiagnosed in emergency departments and often attributed to tendonitis, bursitis, arthritis, or some combination of all three.  To further complicate matters, many other conditions of the shoulder, cervical spine, and peripheral nerve system can produce symptoms that are similar to symptoms occurring in rotator cuff tears.  And finally, a somewhat sizable percentage of the population has asymptomatic rotator cuff tears which makes the determination of the etiology of the cuff defect difficult to determine.

The best way to assess whether a rotator cuff tear is acute or traumatic is with diagnostic imaging.  Numerous studies have found that mid-substance tears are more likely to be acute than insertional tears.  The presence of swelling and joint fluid or a hematoma also suggest that a tear is acute.  To the contrary, the absence of joint and bursal fluid suggests a chronic tear.  The presence of fatty infiltration and the degree of rotator cuff atrophy are also useful findings to assess the chronicity of the tear.  Interestingly, at least one study found that the “injury mechanism and the activity at the moment of injury did not correlate with the presence of a rotator cuff lesion,” but also found “a strong age correlation, with a prevalence of RCTs above 50% in patients aged over 50 years…” This study suggests a shockingly high rate of rotator cuff injury resulting from shoulder trauma in persons over 50. 

The strong correlation between age and rotator cuff tear caused one study’s authors to postulate that “it is even likely that there [is] no such thing as an acute cuff tear without some previous tendon degeneration.”  The authors of another study address the complicated relationship between the chronicity and symptomatic nature of rotator cuff tears and note that the “duration of symptoms does not necessarily reflect the duration a patient has had a rotator cuff tear…  It is not understood why full-thickness tears become symptomatic in some individuals and not others.”  How then, can any physician determine to a reasonable degree of medical certainty if a particular rotator cuff tear relates to the patient’s employment in the absence of diagnostic imaging that suggests a tear is acute?

In truth, the answer is that any physician who attributes a symptomatic rotator cuff tear to a workplace injury is most likely engaging in speculation if there is no acute traumatic event and no diagnostic imaging evidence demonstrating that the tear is acute.  This doesn’t mean that the tear can’t be acute and work-related, simply that there is no reasonable basis for a physician to determine the exact etiology of the tear to a reasonable degree of medical certainty.  In handling claims, it is important to recognize these situations and pose the question to the IME doctor directly as to there is any way, given the current state of evidence-based medicine, to determine what caused a rotator cuff tear (or caused it to become symptomatic) to a reasonable degree of medical certainty in the absence of an acute traumatic event, diagnostic imaging evidence that a tear is acute, or occupational risk factors such as repetitive overhead work.  If there are no specific risk factors, no precipitating injury, and no diagnostic imaging evidence of an acute tear, the answer should always be “no.”

From a claims perspective, there are several useful things that can be gleaned from the medical literature addressing rotator cuff conditions.  First, a definitive assessment of causation in the absence of a discrete, acute precipitating event with imaging evidence demonstrating the presence of an acute tear or an occupational risk factor should be considered impossible.  Of course treating surgeons will attempt to relate rotator cuff conditions to workplace injuries that do not meet the above criteria, but it is incumbent from a claims perspective that the IME physician points to the relevant medical literature and explains why it is not possible, to a reasonable degree of medical certainty, to determine the etiology of a rotator cuff tear in the absence of the above criteria. 

Second, it should not come as a surprise if an employee over 40 who says they hurt their shoulder and is told that it is just a strain or tendinitis when they go the ER later discovers she has a rotator cuff tear.  The medical literature suggests that clinical examination in the emergency setting underestimate the presence of rotator cuff tears.  The relevant study found that in the patient population complaining of an acute shoulder injury who have an inability to perform active abduction above 90° and normal radiographs, more than 50% will have rotator cuff tears.  In establishing reserves, if the medical records show normal radiographs coupled with an inability to actively abduct the shoulder above 90°, it may be wise to consider the likelihood of a rotator cuff tear requiring surgical intervention to be 50%. 

Finally, knowing the different shoulder, neck, and peripheral nerve conditions that have similar symptom constellations to rotator cuff tear will help to assess what the likely diagnosis will be based on the clinical history, examination, and positive findings.  Thus, a shoulder complaint that can be localized to the acromioclavicular joint, is more likely to be a shoulder separation or acromioclavicular arthritis than a rotator cuff tear.  In another example, a complaint of gradual onset of shoulder pain with weakness that is especially noticeable during sleeping hours is likely to be a chronic rotator cuff tear or advanced impingement syndrome than an acute rotator cuff injury.

The bottom line is that shoulder injuries are often difficult claims, especially when they involve rotator cuffs.  Knowing the medical literature about how rotator cuff tears occur and what suggests acute versus chronic tears can help guide the claims analysis.  To learn more about the diagnosis, management, and prognosis of rotator cuff tears, join us on February 26, 2015 for the Medical Systems Advanced Medical Topics in Worker’s Compensation in Brookfield, Wisconsin at which Dr. Bartlett will give an in-depth presentation on acute shoulder injuries.  Claim handlers and legal professionals alike will gain valuable information on what claims will likely be compensable and what medical information can be used to defend against those which should not be compensable.

1/22/2015 in Blog Categories, News

Sit. Type. Sit. Read. Sit. Talk on the phone.  Sit.  Sit.  Sit. Go to a meeting.  Sit.   This is what many of us do for the vast majority of our workday.  We know that sitting all day is bad for our physical health.  We also know that breaking up the day with short walks can help counter the deleterious physical effects of sitting all day.  Now, it appears that a simple lunch time walk can also help with our outlook, energy, and focus at work. 

The New York Times reports on a study conducted in Sweden in which researchers used real time reporting of mood and emotion in a group of office workers assigned to walk at lunch and a control group of office workers who did not walk at lunch.  As the Times notes, “on the afternoons after a lunchtime stroll, walkers said they felt considerably more enthusiastic, less tense, and generally more able to cope than on afternoons when they hadn’t walked…”  The lead author noted that despite the study not addressing workplace productivity, “there is now quite strong research evidence that feeling more positive and enthusiastic at work is very important to productivity…so we would expect that people who walked at lunchtime would be more productive.”  Interestingly, most workers who were part of the walking group said they would not continue walking at lunchtime when the study was over because “they were expected by management to work through lunch.” 

Employers should seek ways in which to encourage employees to engage in less sedentary behavior during the work day.  Employees would be psychologically stronger and more resilient which will almost certainly increase their productivity.  Contrary to popular belief, stepping away from the desk at lunch will actually help you get more done. Encouraging employees to take a lunchtime walk seems like a simple, cost-effective way to improve employee mood and increase productivity.  That being said, I better put on my running shoes…

The employee is a delivery driver and is in a rollover accident.  Miraculously she suffers only minor injuries in the crash.  However, she hits the inside part of her right leg near her knee in the rollover and now, 18 months after the rollover, she still can’t go back to regular duty because she has a permanent foot drop.  Another employee gets his hand stuck in the machine he works on.  The broken bones heal and the tendons are repaired.  Unfortunately, it has been difficult returning him to work because he complains of burning pain every time he touches anything with the injured hand and his doctor has permanently restricted him to one-handed work.

What do these claims have in common?  Peripheral nerve injuries.  Peripheral nerve injuries are complicated, slow-healing, and often result in permanency.  Why are they so complicated and what you can do to make peripheral nerve injury claims go as smoothly as possible?  In this short primer, we hope to answer some of these questions.

To understand why nerve injuries are so challenging, it helps to know some basic nerve physiology.  Nerve cells (neurons) are essentially made up of little factories (axons) that produce chemicals (neurotransmitters) which mediate the electrical signals each nerve cell sends (axon) and receives (dendrite).  Nerve cells are not physically connected to each other and must send the electrical signals across a gap (synapse) to the next nerve cell (dendrite).  The axon of each nerve cell is encased in fatty cells (myelin) that increase the rate at which electrical signals are transmitted between nerve cells.  Branching extensions of the nerve cells (dendrites) receive the electrical signal from the axon of an adjacent nerve cell and transmit the signal to the axon for further transmission.  A failure of any part of this process will disrupt the nerve cell’s functioning and cause sensory or motor problems or both.

Unfortunately, nerve injuries take a long time to heal and often heal poorly because of the complex, compound, and disconnected nature of nerve cells.  Nerve injuries are categorized according to the degree to which the nerve cells are compromised. There are two classification systems – one use three categories and one using six categories.  This post will use the simpler, three part system because it is more concise (the six part system breaks second degree injuries into four subcategories based on the seriousness of the injury).  In first degree injuries, or neurapraxia, the nerve remains intact but its signaling ability is damaged.    Ordinarily persons suffering first degree injuries recover completely without residual sensory or motor impairment.  In second degree injuries, or axonotmesis, the axon is damaged but the surrounding connective tissues remain intact.  Recovery takes longer than in first degree injuries, but complete recovery without residual sensory or motor impairment is still the general rule.  In third degree injuries, or neurotmesis, both the axon and the surrounding connective tissue are damaged.  Recovery is exceptionally long in third degree injuries and typically results in some residual sensory or motor impairment.  In addition, surgery is often necessary to restore function in third degree injuries.  The alternate classification system essentially divides the axonotmesis category into four parts based on the severity of the insult to the axon. 

We will focus on third degree injuries because they are the most difficult to treat and usually result in permanency.  In a third degree nerve injury both the axon and supporting connective tissue are injured.  This means that the nerve cell must regenerate both the axon and its supporting structure.  The regeneration is complicated by a post-injury process called Wallerian degeneration.  Approximately 24-36 hours after the initial injury, the axonal injury disintegrates, the myelin sheath degrades, and macrophages and Schwann cells remove the cellular debris from the injury.  In third degree injuries, the supporting connective tissue (endoneurium), which is a tubular structure containing individual axonal fibers, is severed.  This causes problems because regenerating axonal fibers may meander into surrounding tissue or inappropriate neural tubes, thus failing to reinnervate their proper end organs.  The resulting loss of function is analogous to what would happen in a marionette show if the strings to the marionette controllers are cut and then randomly reattached, sometimes to the correct controller, sometimes to the incorrect controller.  Nothing really works right.

When nerve cells start regenerating after Wallerian degeneration, the process is slow.  Within four days of the injury, the injured axons start sending sprouts toward the neurolemma (tube comprised of Schwann cells surrounding the axon).  Schwann cells produce growth factors that attract the sprouts.  If a sprout reaches a neurolemma, it grows into the tube and advances approximately 1 mm per day until it reaches and reinnervates the target tissue.  Surgery may be necessary to guide the sprouts into the neurolemma when the gap is too wide or scar tissue has formed.  This regeneration and repair phase can last many months.  Human peripheral neurons are capable of initiating a regenerative response for at least 12 months after an injury.  Hence, it can be well after a year from the date of injury before a treating physician or an IME doctor will be able to place a patient who sustained a peripheral nerve injury at maximum medical improvement.

Further complicating matters, third degree injuries do not usually heal completely.  Several factors can contribute to an incomplete recovery.  First, intramuscular fibrosis (scarring) may hinder the muscle contraction a nerve impulse produces.  Erroneous cross-reinnervation may result in impaired functioning (the marionettes with crossed strings).  The imperfect regeneration also results in sensory deficits, especially in proprioception (how the body perceives itself in space), that rarely go away completely.  Even in first and second degree nerve injuries, sensory recovery often takes 6-12 months, so determining whether and to what degree permanent sensory impairment has resulted can take a year or more post-injury. 

The site of the injury itself and the regeneration process can result in the development of neuromas or gliomas, which can increase pain and disability.  If surgical realignment or stump approximation does not occur, the migration of axoplasm may form a neuroma, which is an errant scaffolding (structure) for axonal migration.  Essentially, the strands of axonal fibers get tangled as they seek the distal nerve stump, forming a ball of connective tissue and axonal fibers.  While some neuromas cause no problems, many are painful and impair functioning. 

Treatment and rehabilitation following peripheral nerve injury present their own challenges.  For example, in nerve injuries with extensive damage a graft may be needed to connect the two ends of viable nerve.  Using a graft will leave the patient with a large area of numbness that the donor nerve previously innervated.  The size of this area of numbness will shrink over time, but will not go completely away resulting in residual permanency for loss of sensation at a site remote from the injury.  In addition, nerve regeneration itself can be uncomfortable and accompanied by paresthesia (pins and needles) as the target tissue is reinnervated. 

Some of the direct consequences of peripheral nerve injury included:

  • Pain (ranging from tingling to intense, burning pain)
  • Numbness and altered sensation
  • Muscle weakness
  • Loss of function
  • Loss of active motion
  • Joint stiffness
  • Emotional distress

Unfortunately neuropathic pain is not well-understood and is difficult to treat.  Anticonvulsants and tricyclic antidepressants are the most popular drugs for neuropathic pain.  “Complete relief is very difficult and only 40-60% of patients achieve partial relief.”  The persistence and refractory nature of neuropathic pain causes psychological distress and is difficult to understand for persons who are accustomed to the way more typical musculoskeletal pain responds to conventional analgesic medications.  From a claims standpoint, neuropathic pain presents great impediments to returning claimants to work because claimants are conditioned to equate pain with physical disability and loss of function, but neuropathic pain frequently does not impair function and is only disabling from a psychological perspective (not to diminish the psychological distress that neuropathic pain causes).  It is critical for return to work efforts that the treating physicians and occupational/physical therapists convey the distinction between neuropathic and musculoskeletal pain to the claimant to avoid protracted disability beyond the period of actual physical impairment caused by the injury.

Weakness and loss of function are common complications of third degree nerve injuries because even in the best case scenario nerve regeneration is imperfect.  As noted above, weakness and loss of function result from many complicating factors including slow regrowth causing irreparable muscle atrophy, imperfect regrowth resulting in loss of function, and the presence of scar tissue in the muscle preventing normal contracture.  This presents challenges to the claim handler who must attempt to gauge return to work, appropriate rehabilitation, and permanent partial disability.  EMG can determine the rate at which nerves are growing and muscles are reinnervating, but functional use/restoration will lag behind reinnervation.  The reinnervated muscles have been without innervation for a time, so the body must relearn how to use the muscles again which takes time.  In addition, the muscles are usually reinnervated imperfectly, so the body is not only relearning how to use the newly innervated muscles, but it is also learning a new neural pattern of action.  The body cannot rely on muscle memory to speed the relearning process because the newly configured reinnervation is different than it was before, meaning muscle memory itself is altered or lost. 

Some studies have found that conservative therapies can be used alone or in conjunction with surgery to help restore function in peripheral nerve injuries.  Laser phototherapy “maintains functional activity of the injured nerve for a long period, decreases scar tissue formation at the injury site, decreases degeneration in corresponding motor neurons of the spinal cord and significantly increases axonal growth and myelinization.”  In addition, acupuncture has been found to be an effective treatment modality in improving the rate of recovery.  In managing nerve injury claims, it is important to know what therapies work and what do not.  Effective claim handlers should be conversant in treatment modalities that can hasten recovery and improve ultimate function so they can ensure patients with peripheral nerve injuries receive the treatment that will get them to an end of healing the fastest and will minimize the inevitable permanent partial disability rating.

Even with effective conservative treatment modalities such as laser phototherapy or acupuncture, recovering function and building strength in peripheral nerve injuries are long and arduous processes that require skilled therapy and a motivated patient.  If either variable is lacking, recovery is likely to be compromised.  A supreme difficulty for claim handlers is managing the nerve injury case where either the employee lacks motivation or their choice of treating therapist appears to be wanting in some fashion.  Early engagement in the claim can help foster a “can do” attitude in the injured worker and a positive relationship with the therapist so that he or she pushes the worker and provides the highest and best evidence-supported rehabilitative care.

The Medical Systems, Inc. “Advanced Topics in Worker’s Compensation Symposium” will address these and other issues related to severe, acute industrial injuries to the hand and wrist with Dr. Jan Bax.  Join us to learn why severe hand and wrist injuries present such difficult challenges, what the best medical and surgical treatments of these injuries are, and what strategies you can utilize to help claimants get the best physical recovery and (in the process) lower your costs. 

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