Medical Exhibits - Demonstrative Evidence Expert Blog - MediVisuals

By: Robert Shepherd MS, Certified Medical Illustrator, Vice President and Director of Eastern Region Operations, Medivisuals Incorporated

Brain injuries are classified into two basic categories; those that are associated with obvious, incontestable evidence of intracranial injury and those that are not.

Obvious intracranial injuries include those with evidence of pathology within the brain itself (intraparenchymal injuries) as well as areas of bleeding around the brain but within the skull. The light area in the scan below indicates blood within the brain tissue, and the surrounding dark area shows associated edema. Both of these are considered to be intraparenchymal injuries. Contusions and hematomas found outside the skull are not considered intracranial but are frequently illustrated to help emphasize the force and direction of the trauma to the head. 

The areas of hemorrhage shown in the illustration below are scattered around the junction between the grey and white matter of the brain, which is consistent with injuries from shear forces. The grey and white matter are of different densities, and when the brain impacts the skull during a traumatic event, the subsequent unequal movement between the two causes damage at their junction.

Head trauma can cause tearing of the blood vessels around the brain, which can result in areas of bleeding (hematomas). As the bleeding continues, the hematoma may expand to compress the brain tissue (as shown in the following illustration) and may require an emergency decompression. Significant compression must be relieved quickly in order to avoid further neurological damage and/or death. 

Introducing a ventriculostomy catheter is one approach used to alleviate increased intracranial pressure. A hole is drilled directly into the patient's skull, and a catheter is advanced through the brain tissue into one of the ventricles. The catheter allows some of the cerebrospinal fluid to escape, thereby relieving the pressure on the brain itself.

In other situations, a craniotomy may be performed to allow the blood to be suctioned from the area surrounding the brain. A bone flap is created by first drilling three holes into the skull and then making cuts between them with a saw. This flap is removed and the blood is cleared from the areas above and beneath the dura. In some cases, the bone flap is not replaced if the brain is swollen or if there is a significant concern over recurrence of the hematoma. For a more detailed look at the craniotomy procedure, please review MediVisuals Craniotomy Surgery Animation. 

Everyone knows the McDonald's Hot Coffee case -- or at least everyone thinks they know about the McDonald's Hot Coffee case. Most of America still does not know the truth. When the case first hit the media, news groups misstated the facts, and television programs joked or performed spoofs about the case. Even "The Oprah Winfrey Show" was guilty of fanning the fire of misconception until they learned of the real facts of the case and, in a later show, recanted what was initially said.

"Hot Coffee The Movie" is a documentary that reveals the truth about the McDonalds Hot Coffee case. It also examines "tort reform" and its threat to our civil justice system by following four people, including the McDonald's Hot Coffee plaintiff, Stella Liebeck, through their struggles in accessing the court system.

The documentary was directed by former trial lawyer and first-time filmmaker Susan Saladoff and has been selected for numerous film festivals, including the prestigious Sundance Film Festival. It has also been awarded "Best Documentary" at the Seattle Film Festival and Tampa Gasparilla Film Festival. The documentary will premiere on HBO on Monday, June 27, at 9:00PM EST as part of their Summer Documentary Series. The trailer can be viewed using the following link: http://hotcoffeethemovie.com/

MediVisuals was proud to support this project by helping raise funds for development of the documentary and by providing images and animations. Some of the facts about the case detailed in the documentary are as follows:
 
· Over 700 complaints of injuries from hot coffee were filed against McDonalds prior to the one that received so much notoriety

· The plaintiff was not driving the vehicle, nor was it moving when the spill occurred (she was a passenger in a vehicle sitting still in the parking lot)

· The coffee resulted in severe third degree burns in the plaintiff's groin region and thighs (there are very graphic photos of the severe burns)

· The plaintiff had to undergo skin grafting to address the injuries

· The plaintiff initially only requested that McDonalds pay her medical bills

· Because the facts lead the jury to conclude that McDonalds was exceptionally negligent in its behavior, the jury awarded the plaintiff ~$160K in compensatory damages and ~$2.7 million in punitive damages

· The $2.7 million was equivalent to the profits to only 2 days of McDonald's coffee sales

· The judge then reduced the award to $480K so the plaintiff and attorney received very little for their time and effort pursuing justice

For more information on Hot Coffee: The Movie, please visit: http://hotcoffeethemovie.com/

Several long term or permanent complications may result from a fracture injury. Traumatic arthritis may be one of the most common long term debilitating complications. (See the previously posted article "Breaking Down Traumatic Arthritis" for more information.) These complications may even require additional surgical procedures.

Normally, fractures begin healing by forming a callus which is then replaced by bone. With a nonunion (see image below), the callus is replaced by fibrous tissue instead of by bone. This is a painful condition that is most frequently treated by surgery to remove the fibrous tissue, debride the surrounding bone and re-approximate the remaining fragments (sometimes with bone graft material and fixation devices).

Malunion is another frequently occurring complication of fractures. With malunion, the bones heal, but they do so at an unusual angle that can effect range of motion and/or cause pain (see image below). Treatment typically involves refracturing or cutting the bones, realignment, and fixating them with hardware so that they heal in the correct position.

Intra-articular “step-offs” are a complication of intra-articular fractures. A “step-off” is a type of malunion in which the bone heals, but it heals so that the joint surfaces are not aligned in a smooth continuous surface. The illustration below shows a fracture through the patella that healed with a painful “step-off.”

Like all organ systems, bones require a blood supply. If the blood supply is disrupted, the bone can die and collapse. This condition is known as avascular necrosis. The scaphoid is a bone in the wrist that is frequently affected by avascular necrosis. In the illustration below, a fracture is seen through the scaphoid and its blood supply.  As a result, the small fractured fragment loses its blood supply and over time, becomes necrotic. Treatment would likely involve fusion of the wrist bones. Other bones that are particularly vulnerable to avascular necrosis include the femoral head (hip joint) and the talus (ankle joint).

Ossification of the surrounding soft tissues is another complication of fractures. This condition is referred to as “heterotopic ossification” and/or “myositis ossificans”. With this condition, the bone cells that form to heal the fracture extend out into the surrounding tissues (see image below) resulting in pain and decreased range of motion. Treatment involves surgery to excise the excessive bone growth.

By: Robert Shepherd MS, Certified Medical Illustrator, Vice President and Director of Eastern Region Operations, MediVisuals Incorporated

The following animation contains sequences that are intended to help support expert witness testimony regarding one of the causes of failure of certain types of knee prostheses (such as the Zimmer NexGen knee prosthetic).

The animation focuses on the cementless cobalt-chromium-molybdenum (CoCrMo) alloy prosthesis. It compares how new bone normally fuses with a prosthesis versus how ions emitted from the CoCrMo alloy inhibit osteoblasts (cells that are responsible for bone formation) from forming new bone. Fibroblasts (cells responsible for fibrous tissue formation, such as collagen) are less inhibited by the CoCrMo ions; therefore, the fibroblasts form fibrous tissue between the bone and prosthesis. This weak and inadequate fusion allows movement and loosening between the femur and prosthesis resulting in prosthesis failure.

By: Robert Shepherd MS, Certified Medical Illustrator, Vice President and Director of Eastern Region Operations, MediVisuals Incorporated

A traumatic event causing injury to an intervertebral disc may also cause subtle injuries to the bones around the disc. During an extreme lateral flexion injury (shown in the image below), the edges of the bone are driven together, injuring both the disc and the bone. As the bone/disc junction heals, overgrowths referred to as osteophytes may form.

Osteophytes take weeks or months to develop following a traumatic event; therefore, any osteophytes that are present soon after a traumatic event are likely pre-existing.

The osteophytes themselves may compress the neural elements as in the illustration above; however, in most situations, the osteophytes are a part of an OSTEOPHYTE/DISC COMPLEX. This is when the osteophytes and disc extend beyond their normal limits and compress the neural elements (spinal cord, nerve roots). In cases where osteophytes may have pre-existed a traumatic event, worsening of the disc bulge could occur following the trauma, resulting in new or aggravated symptoms.

Sometimes disc and ligament injuries occur on the same side as the force of impact. Other times, they occur on the opposite side. Injuries to the disc on the same side as the force are the result of stretching and tearing forces. On the opposite side, compression forces result in tears and micro fractures of the tissues and bones. (see illustration below). Osteophytes and facet hypertrophy can also form following injuries to intervertebral discs and ligaments. Injuries to the discs and ligaments result in instability and excessive motion of the joints that, in turn, results in constant trauma to the bone/disc and ligament junctions. This ongoing trauma results in overgrowth of the bones as it continually cycles through episodes of healing and reinjury.

By: Trisha Kreibich, MS Medical Illustrator/Consultant and Robert Shepherd MS, Certified Medical Illustrator, Vice President and Director of Eastern Region Operations, MediVisuals Incorporated

There has been a lot of buzz about the DePuy Hip Replacement Implant Recall, but few visual aids are available to help people understand the mechanism behind the implant's failure.

In order to provide attorneys and physicians with the tools needed to help explain this effectively to the people with these implants and their families, MediVisuals has created the Metal-on-Metal Hip Replacement Recall Animation Series. The first of this series focuses on (1) the metal on metal wear and (2) how placement of the acetabular component at too steep an angle significantly increases the pounds/mm2 pressure on the devices resulting in increasing friction and metal discharge into the joint space.

This article will explain the sequences through a series of screen shots taken from the animation. A link to view the full animation is available at the end of the article. (First, we recommend reviewing the surgical steps involved in a typical hip replacement procedure, by clicking the following link: Total Hip Replacement Surgery Animation)

The image below shows the pelvis and hip anatomy. The left hip [appears on right side of image] is normal, while the right hip [appears on the left side of image] has a hip replacement implant.

The next image shows a detailed view of the implant. The STEM is inserted into the reamed femur. Attached to the stem are the FEMORAL COMPONENTS. These articulate with the ACETABULAR COMPONENT, which is inserted into the reamed acetabulum of the pelvis. The femoral components and acetabular component together create the familiar "ball-and-socket" joint that allows for a wide range of movement.

As shown in the image below, the desired 45 degree angle placement of the acetabular component results in the majority of the weight-bearing forces being placed on the upper-outer portion of the ball and socket (edge loading). In many cases, the acetabular component is placed at a steeper angle. When placed at an angle of 52 degrees or greater, the amount of force on the edge of the ball and socket is significantly higher and, as the animation will proceed to show, so is the failure rate of the implant.

In a normal hip and most hip replacements, synovial fluid is able to enter the joint space and provide lubrication. However, some implants are manufactured in a way that the space between the femoral head and acetabular components is so tight that the synovial fluid is unable to enter the joint space.

Without this necessary lubrication, the result is direct metal-on-metal wear. The combination of the increased weight-bearing surface and direct metal-on-metal wear results in tiny metal fragments, or ions, fracturing off into the joint capsule.

These metal fragments (ions) irritate the joint capsule and surrounding tissues, triggering an immunological response known as metallosis. This condition can lead to inflammation, weakness, pseudotumors, and eventual necrosis of the tissues around the joint.

Prolonged exposure increases the concentration of metal ions in the body. This build up can adversely affect numerous physiological systems of the body, and may also increase the risk of development of cancer in some patients. For these reasons, the removal of the implant and replacement with a different device (revision surgery) must be strongly considered, even in situations where the patient is not suffering from noticeable complications associated with the recalled implant. 

To view the full animation, please click the image below or the following link: Understanding Edge Loading, Metal Fragment Discharge, Inflammation & Metallosis Associated with Metal-on-Metal Hip Replacement Implants To view additional medical exhibits related to this topic, please visit the following MediVisuals webpage: Metal-on-Metal Hip Replacement Recall Animation Series

By: Robert Shepherd MS, Certified Medical Illustrator, Vice President and Director of Eastern Region Operations, MediVisuals Incorporated

It is now possible for two or more people to simultaneously "share" computers from anywhere in the world through web conferencing. One of the best applications we at MediVisuals have found for this software is to enable the attorney, medical expert and medical illustrator to review and discuss imaging studies simultaneously from their respective offices.

Web conferencing significantly reduces travel time and expense. For example, a recent case required us to team up with a testifying expert located in the Midwest and an attorney in another region. Instead of meeting face-to-face, we tried screen-to-screen contact and found it worked remarkably well. Web conferencing enabled all three of us to maneuver through the imaging studies and move the cursor to specific areas of the films that were being discussed. This, along with simple telephone conferencing, allowed us all to speak with each other as we viewed the same images on our respective computer screens.

Web conferencing makes it easier than ever for us to work with attorneys and medical experts anywhere in the world. The required software programs are simple to use and affordable. The main hurdle involves ensuring the other participants' computers have fast and reliable Internet connections (i.e. DSL or Broadband) and that their web browsers are up-to-date to support the software. Confirming the second/third party Internet and computer capabilities takes no more than a phone call.

Most web conferencing software providers offer a free trial and quick web tutorial, which decreases the learning curve associated with understanding a new program. For the real tech-savvy, some developers even offer applications adaptable to 3G and 4G Smartphones and devices such as the iPad.

If you are interested in introducing web conferencing to your firm, the following is a list of links to recommended software providers’ websites:

Log Me In
http://www.logmein.com

Go To Meeting
http://www.gotomeeting.com

Cisco WebEx
http://www.webex.com/

Yugma
https://www.yugma.com/

MegaMeeting.com
http://www.megameeting.com/

By: Robert Shepherd MS, Certified Medical Illustrator, Vice President and Director of Eastern Region Operations, MediVisuals Incorporated

On occasion, it is uncertain exactly which intervertebral disc may be causing a plaintiff’s pain.  Physicians may conduct a discography study prior to surgery in these cases.

This procedure involves advancing needles into the discs in question and injecting contrast material that serves two purposes:  (1) The contrast material makes it possible to better analyze the exact defects (if any) in the discs when X-rays or CTs are taken after the administration of the contrast material. (2) The contrast material also increases the pressure within the disc causing it to expand and subsequently compress the nearby nerve roots.  If     the pain corresponds to the patient’s normal pain, then that disc is determined as the     “problem disc”.

When pain is thought to be associated with irritation or inflammation of the nerve root(s) or surrounding tissues, epidural injections can be performed. As shown in the animation below, epidural injections involve administering anesthetics and steroids around the nerve root(s).  These injections can be used as a diagnostic tool as well as a treatment.

If the epidural injections are ineffective, the cause of the pain may not be related to the nerve root(s).  If the injections are effective, it confirms the nerve root(s) as the source of the pain. Repeated treatments may resolve the pain; if not, more aggressive treatments may be necessary.

Sometimes the facet joints themselves can be the source of pain. One of the terms used to refer to this condition is “facet arthropathy”.  This condition results from the breakdown of the normal, healthy joint spaces. With the breakdown of these articular surfaces, the joints become painful with each movement.

Each facet joint is supplied by a small dorsal branch of the adjacent nerve root [see illustration below].  Injections in or around the facet can again serve to determine the painful facet(s) and help resolve the pain.

If facet joint injections are unsuccessful at resolving the pain, the nerves to the facets can be destroyed by a procedure known as ablation. Ablation involves advancing a needle adjacent to the facet nerve and destroying it, thereby eliminating the pain.

This article is a continuation of a two part article on brachial plexus injury. Part 1 covered brachial plexus injuries in adults caused by a traumatic event, such as a motor vehicle collision. Part 2 will address brachial plexus injury in infants during delivery, which is also known as Shoulder Dystocia or Erb's palsy.

To review, the brachial plexus innervates the arm and is formed by several of the cervical nerve roots and the T1 nerve root. [see illustration below]

During delivery, the infant's passage through the birth canal can be stopped by the impaction of its shoulder(s) against the mother's pubic bone, sacral promontory, or both. [see illustration below]

Injury to the brachial plexus may sometimes occur because of unusually powerful uterine contractions or rapid fetal descent; however, brachial plexus injury may also result from improper obstetrician interaction. When excessive downward traction on the head of an infant with shoulder dystocia is applied (a violation of the standard of care), the delicate brachial plexus is stretched and injured. [shown below] The same may also occur when vacuum extraction is used in this situation.

As in adult brachial plexus injuries, the earlier the injury is identified and treated, the better chances are for recovery and preventing permanent damage. However, this is also dependent on the severity of the initial injury. Sometimes, an overgrowth of nerve cells (neuroma) can form around the injured nerves. When this occurs, surgical intervention and nerve grafting may be needed. [see illustration below]

There are some delivery techniques that can be used to prevent brachial plexus injury in infants with shoulder dystocia. As the illustration below demonstrates, the mother is moved to the McRoberts position, where her legs are hyperflexed to the abdomen, typically resulting in an increase of the outlet. This is often used in conjuction with an episiotomy, a cut made in the perineal body (tissue between the vagina and anus) before delivery, to enlarge the outlet and allow the obstetrician more room to perform maneuvers.

If no progress is made, moderate suprapubic pressure may be applied to free the impacted shoulder. The Wood's screw maneuver [shown below] may be used as well. This maneuver involves the obstetrician rotating the infant's anterior or posterior shoulder, and in turn the body, like a screw, freeing the impacted shoulder.

The following animation was developed to show how brachial plexus injuries can occur in a shoulder dystocia case, along with a few of the above mentioned accepted procedures that can be performed to help prevent this injury.

Reference:

Gabbe, S.G., Niebyl, J. R., & Simpson, J.L. "Obstetrics: Normal & Problem Pregnancies." 3rd ed. Philadelphia: Churchill Livingstone, 1996. 374-375, 490-494. Print.

By: Robert Shepherd MS, Certified Medical Illustrator, Vice President and Director of Eastern Region Operations, MediVisuals Incorporated

Injuries to the brachial plexus can often take place from trauma similar to that which causes cervical spine injuries and can also manifest similar symptoms. As shown in the illustration below, the brachial plexus is formed by several of the cervical nerve roots and the T1 nerve root.

Sometimes injury to the brachial plexus can be the direct result of excessive stretch during a traumatic event. For example, in a motor vehicle collision with a violent side impact the nerves on the contralateral side of the impact (and resulting flexion) may be stretched and/or torn. [see illustration below]

Injury to the surrounding muscles can indirectly cause injury to the brachial plexus, as well. The brachial plexus runs between the anterior and middle scalene muscles, which connect the cervical spine and first rib. In a motor vehicle collision, hyperextension of the neck may excessively stretch these muscles, as demonstrated in the illustration below.

When these muscles are stretched, the resulting swelling or spasm can result in symptoms consistent with cervical nerve root injury even though the cervical nerve roots or brachial plexus themselves may not be directly injured. [see illustration below]

Thoracic outlet syndrome is another mechanism by which the brachial plexus can be injured. The illustration below shows that the axillary sheath, which contains the nerves from the brachial plexus and the axillary vein and artery, passes through the opening created between the clavicle and first rib.

Thoracic outlet syndrome can occur either by (1) the elevation of the first rib due to spasm of the scalenes or (2) the loss of innervation to the trapezius and/or other muscles that insert on the clavicle or scapula, causing the shoulder to droop [see illustration below]. By either mechanism, the opening between the clavicle and first rib is closed and the nerves and blood vessels that travel through the thoracic outlet become compressed.

As one can see in the illustration below, an injury to the brachial plexus affects the motor and sensory function of the arm. The earlier the injury is identified and treated, the better chances are for recovery and preventing permanent damage. However, this is also dependent on the severity of the initial injury. Sometimes surgical intervention is needed to address torn/ruptured nerves and excessive scarring.

This is the first of a two part article. Please check back to read Part 2, which discusses brachial plexus injury in infants during delivery (Shoulder dystocia). You can also sign up for email alerts, which announce when another article has been posted.