Mechanistic Interplay between the peripherey, brain and spinal cord

For those of you following our journey through the 3rd World Congress on Abdominal and Pelvic Pain (#WCAPP17), here is another light-bulb lecture explaining the interconnections of chronic visceral pain. The presenter, Melissa A. Farmer, PhD, is a researcher at the Feinberg School of Medicine at Northwestern University with a long-standing relationship with the International Pelvic Pain Society (the organizer for #WCAPP17). So, needless to say, she has an impressive resume and a passion for understanding pelvic pain. Just check out her wrap sheet. I’ve chosen a few interesting nuggets from her lecture.

Three Camps

Pain, pain, pain. There are three camps of pain chronification:

Cortical reorganization: occurring in the brain

Spinal central sensitization: occurring at the spinal cord

Nociceptive sensitization: occurring at the sensory nerve level

Each of these camps have their own combination of modifiers that can lead to sensitization.

Pause- so this is where one can get overloaded with information, so I took some creative liberties and decided to draw a picture.

Recreated from a presentation given by Dr. Farmer

As you see from the drawing, there are several areas where our brain and our body can modify signals related to pain. At the “nociceptor sensitization camp” the sensory nerves can become extra excited, and maybe throw too much input into the nervous system. For example, do you remember the last sunburn you had? Remember how sensitive your skin was- even the slightest touch was immensely painful. Well, now imagine that you don’t have a sunburn but your nerves are sending that same intense signal, as if your tissue was still burned. This nervous system mix up is called allodynia, when normally non-painful stimulus is extremely painful.

At the “stream of spinal central sensitization” the spinal cord can send information upstream, to the brain, or downstream, to the peripheral nerve, to modify signals related to pain. For example, #1 on the list, prolonged dorsal horn firing, is similar to an echo. This is when your hand-nerve yells “watch out” to your spinal cord, and your spinal cord yells to your brain “watch out….watch out….watch out….watch out….watch out… watch out…watch out….” well you get the idea. A single signal potentiates into multiple.

Finally we have the “lake of cortical reorganization”, or in layman’s terms, brain change. Here you can have tidepools of emotional distress or reefs of prior history or insert another water-based metaphor here. Essentially, upcoming signals are then interpreted within the framework of the brain where it decides if it’s enough to produce a pain response. How this all works is a bit murky, pardon the pun, but we do know that our interpretation of nociceptive signals greatly impacts how the brain choose to deal with them.

Somatic vs. Visceral: Crosstalk

Dr. Farmer also touched on the differences between somatic and visceral pain and the crosstalk that can occur between the two.

When comparing sensations from somatic (aka your body) and visceral structures (aka your organs), there are several differences. Somatic pain has a distinct quality, like a sharp or pinching sensation. It correlates specifically to the intensity, duration and location of the stimulus and is caused by tissue injury and inflammation. One easy example of somatic pain is the ankle pain one might experience following a sprain. Conversely, visceral pain is diffuse in quality and generally is found along the midline of the body. It doesn’t have the same on/off switch and tends to correlate very poorly with its stimulus. Just think how you felt the last time you had food poisoning…yah not fun.

Okay, that seems reasonable, now we have some ways to separate out different types of pain. However, sometimes messages can get muddled when somatic and visceral structures start to talk to one another – called crosstalk. This can happen when sensory fibers of pelvic organs synapse close by where other somatic or visceral structures synapse at the spinal cord. You can see how it can get confusing when a problem in one organ might feel like a problem in a completely separate organ or body part.

One case of this is viscero-somatic pain, when a visceral structure creates body pain. A well-known example of viscero-somatic pain is when during a heart attack someone might report significant left arm pain. In the pelvis however, this would look like a patient complaining of low back pain when the stimulus is actually coming from uterine contractions.

This crosstalk can also go the opposite direction, somato-visceral pain. This could happen with vulvar inflammation. A patient may have multiple yeast infections leading to inflammation of the vulva (somato-), but then also experience bladder pain (visceral). And it doesn’t stop there.

Viscero-visceral pain, yup that happens. Stimulus from one organ can be confused with stimulus from another organ. This can even lead to changes in how the organs function. This type of viscero-visceral pain is one explanation for the high prevalence of irritable bowel syndrome in women with endometriosis.

What does this mean for patients?

So now what? All of this can be quite overwhelming. It’s important for both patient and practitioners to educate themselves regarding the different facets of pain. Great resources including Dr. Farmer’s research and books like Explain Pain or Pelvic Pain Explained can be very helpful in help navigating these uncertain waters. Since knowledge is power, the more we understand the cause, the better we can treat pain together.

Thank you again for the enlightening presentation Dr. Farmer! If you want to check out the whole presentation, which we recommend, look here.

FAQ

What are pelvic floor muscles?

The pelvic floor muscles are a group of muscles that run from the coccyx to the pubic bone. They are part of the core, helping to support our entire body as well as providing support for the bowel, bladder and uterus. These muscles help us maintain bowel and bladder control and are involved in sexual pleasure and orgasm. The technical name of the pelvic floor muscles is the Levator Ani muscle group. The pudendal nerve, the levator ani nerve, and branches from the S2 – S4 nerve roots innervate the pelvic floor muscles. They are under voluntary and autonomic control, which is a unique feature only they possess compared to other muscle groups.

What is pelvic floor physical therapy?

Pelvic floor physical therapy is a specialized area of physical therapy. Currently, physical therapists need advanced post-graduate education to be able to help people with pelvic floor dysfunction because pelvic floor disorders are not yet being taught in standard physical therapy curricula. The Pelvic Health and Rehabilitation Center provides extensive training for our staff because we recognize the limitations of physical therapy education in this unique area.

What happens at pelvic floor therapy?

During an evaluation for pelvic floor dysfunction the physical therapist will take a detailed history. Following the history the physical therapist will leave the room to allow the patient to change and drape themselves. The physical therapist will return to the room and using gloved hands will perform an external and internal manual assessment of the pelvic floor and girdle muscles. The physical therapist will once again leave the room and allow the patient to dress. Following the manual examination there may also be an examination of strength, motor control, and overall biomechanics and neuromuscular control. The physical therapist will then communicate the findings to the patient and together with their patient they establish an assessment, short term and long term goals and a treatment plan. Typically people with pelvic floor dysfunction are seen one time per week for one hour for varying amounts of time based on the severity and chronicity of the disease. A home exercise program will be established and the physical therapist will help coordinate other providers on the treatment team. Typically patients are seen for 3 months to a year.

What is pudendal neuralgia and how is it treated?

Pudendal Neuralgia is a clinical diagnosis that means pain in the sensory distribution of the pudendal nerve. The pudendal nerve is a mixed nerve that exits the S2 – S4 sacral nerve roots, we have a right and left pudendal nerve and each side has three main trunks: the dorsal branch, the perineal branch, and the inferior rectal branch. The branches supply sensation to the clitoris/penis, labia/scrotum, perineum, anus, the distal ⅓ of the urethra and rectum, and the vulva and vestibule. The nerve branches also control the pelvic floor muscles. The pudendal nerve follows a tortuous path through the pelvic floor and girdle, leaving it vulnerable to compression and tension injuries at various points along its path.

Pudendal Neuralgia occurs when the nerve is unable to slide, glide and move normally and as a result, people experience pain in some or all of the above-mentioned areas. Pelvic floor physical therapy plays a crucial role in identifying the mechanical impairments that are affecting the nerve. The physical therapy treatment plan is designed to restore normal neural function. Patients with pudendal neuralgia require pelvic floor physical therapy and may also benefit from medical management that includes pharmaceuticals and procedures such as pudendal nerve blocks or botox injections.

What is interstitial cystitis and how is it treated?

Interstitial Cystitis is a clinical diagnosis characterized by irritative bladder symptoms such as urinary urgency, frequency, and hesitancy in the absence of infection. Research has shown the majority of patients who meet the clinical definition have pelvic floor dysfunction and myalgia. Therefore, the American Urologic Association recommends pelvic floor physical therapy as first-line treatment for Interstitial Cystitis. Patients will benefit from pelvic floor physical therapy and may also benefit from pharmacologic management or medical procedures such as bladder instillations.

Who is the Pelvic Health and Rehabilitation Team?

The Pelvic Health and Rehabilitation Center was founded by Elizabeth Akincilar and Stephanie Prendergast in 2006, they have been treating people with pelvic floor disorders since 2001. They were trained and mentored by a medical doctor and quickly became experts in treating pelvic floor disorders. They began creating courses and sharing their knowledge around the world. They expanded to 11 locations in the United States and developed a residency style training program for their employees with ongoing weekly mentoring. The physical therapists who work at PHRC have undergone more training than the majority of pelvic floor physical therapists and as a result offer efficient and high quality care.

How many years of experience do we have?

Stephanie and Liz have 24 years of experience and help each and every team member become an expert in the field through their training and mentoring program.

Why PHRC versus anyone else?

PHRC is unique because of the specific focus on pelvic floor disorders and the leadership at our company. We are constantly lecturing, teaching, and staying ahead of the curve with our connections to medical experts and emerging experts. As a result, we are able to efficiently and effectively help our patients restore their pelvic health.

Do we treat men for pelvic floor therapy?

The Pelvic Health and Rehabilitation Center is unique in that the Cofounders have always treated people of all genders and therefore have trained the team members and staff the same way. Many pelvic floor physical therapists focus solely on people with vulvas, this is not the case here.

Do I need pelvic floor therapy forever?

The majority of people with pelvic floor dysfunction will undergo pelvic floor physical therapy for a set amount of time based on their goals. Every 6 -8 weeks goals will be re-established based on the physical improvements and remaining physical impairments. Most patients will achieve their goals in 3 – 6 months. If there are complicating medical or untreated comorbidities some patients will be in therapy longer.