Parsonage-Turner Syndrome affects the nerves controlling the shoulder, arm and hand. “We published data on the first successful surgical treatment in patients who experienced some degree of paralysis due to this mysterious disorder,” said Scott W. Wolfe, MD, director of the Center for Brachial Plexus and Traumatic Nerve Injury at HSS and lead investigator.

Also known as neuralgic amyotrophy, Parsonage-Turner Syndrome most frequently manifests as sudden, severe pain in the shoulder and upper arm, often with no known cause. The intense pain, which usually subsides within a couple of weeks, is followed by progressive weakness. Many patients find they are unable to move their affected shoulder, elbow or hand. The area and degree of paralysis depend on the nerves affected and the muscles they control.

There is no known cure, but doctors generally prescribe pain medication, steroids and physical therapy to help relieve symptoms. Although many patients eventually recover and regain function of their arm, it sometimes takes several years.

For those who do not get better, limited use of their arm or even complete paralysis can be devastating. “Imagine going for months with this condition and not knowing if or when you’re going to get better. Because recovery can take a year or longer, patients have been told to wait, and there’s this feeling of uncertainty,” says O. Kenechi Nwawka, MD, director of the Division of Ultrasound Research at HSS, who performs ultrasound in PTS patients to locate the damaged nerves. “Many patients who come to HSS feel relieved because they have found a group of specialists that really understands their condition.”

Dr. Wolfe and colleagues set out to determine if patients who weren’t improving could be helped by neurolysis, a microsurgical procedure to repair the injured nerve. The doctors hypothesized that successful surgery would allow patients with PTS to regain strength and movement.

To help patients with Parsonage-Turner Syndrome, a multidisciplinary team of specialists is essential. The first step is for a physiatrist to identify which muscles are involved and assess the nerve injury and loss of function. This is achieved through electrodiagnostic testing, which is used again at a later date to look for signs that the nerve is recovering.

It is also critical to pinpoint the exact location of the damaged nerve or nerves with MRI and ultrasound. Hospital for Special Surgery is one of few centers nationwide with the highly specialized team of hand surgeons, physiatrists and radiologists who could pursue such an undertaking.

“Without this team of experts in these varied, but related fields, we could not have made as much progress in a relatively short period of time,” said Dr. Wolfe. “It is not only the members of the team, but the spirit of collaboration among my medical and surgical colleagues at HSS that sets us apart from other institutions.”

The HSS study enrolled 24 patients with PTS, all of whom had suffered paralysis of their arm or hand. A physiatrist performed electromyography (EMG) to measure muscle and nerve function in all the patients.

“EMG testing is first used to confirm and make the definitive diagnosis of PTS,” explained physiatrist Joseph H. Feinberg, MD, medical director of the Center for Brachial Plexus and Traumatic Nerve Injury at HSS. “A damaged nerve will generally start to recover in six to nine months, and additional EMG testing can indicate if there are early signs of nerve regeneration. If the nerve is starting to regenerate, the patient will likely regain muscle strength, so surgery is generally not needed. However, if there is no sign of regeneration within six to nine months of PTS onset, then recovery is less likely, and surgery may be considered.”

Patients in the study met the following criteria: 12 months had passed without improvement since the onset of Parsonage-Turner Syndrome, or there was no evidence of clinical or electrodiagnostic improvement after six months as documented by three successive EMG and clinical exams.

A high-resolution MRI technique known as magnetic resonance neurography (MRN) was performed to zero in on the location of the nerve damage. Previously, radiologists at HSS had documented “hourglass-like” constrictions of the nerve, an anomaly that is unique to patients with PTS. Essentially, a band squeezing the nerve makes it look like an hourglass on the digital image. The MRI, along with high-resolution ultrasound images, is essential in surgical planning.

“Magnetic resonance neurography and ultrasound images give the surgeons a roadmap, a target to treat,” explained Darryl B. Sneag, MD, director, Peripheral Nerve, MRI at HSS. “Instead of having to explore the entire nerve in an arm, the images pinpoint the exact location of the constriction, so the surgeon doesn’t have to spend hours searching for it.”

Hourglass-like constrictions of affected nerves were identified in each study patient, and the images were correlated with EMG findings. Eleven out of the 24 patients opted for neurolysis surgery by Dr. Wolfe and his colleague, Steve K. Lee, MD.

“Once we localized the tiny constrictions in the nerve with imaging, we could confine our surgery to that site, and we could locate the lesion with millimeter precision,” said Dr. Wolfe. “Looking through a microscope with 25X magnification, we then repaired the constricted nerve by releasing the compressive bands around it.”

The mean time from PTS onset to surgery was 12.5 months. At patient follow-up of almost 15 months after the procedure, nine of the 11 patients who had surgery showed clinical improvement, having regained muscle strength and movement. EMG testing revealed significant motor unit recovery from nerve regeneration.

Out of the 13 patients who did not have surgery, only three had recovered strength during follow-up, which took place almost three years after PTS onset.

“Microsurgical neurolysis to repair the hourglass constrictions was associated with dramatic and significantly improved clinical outcomes and nerve regeneration compared to nonsurgical management,” Dr. Wolfe noted. “Therefore, we recommend considering it as a treatment option for patients with chronic Parsonage-Turner Syndrome who have failed to improve with nonoperative treatment.”

The condition is characterized by sudden pain in the shoulder and upper arm, often so intense that many people go the emergency room. It tends to strike young, otherwise healthy adults, usually on one side of their body. For many, it happens suddenly with no known cause. The pain usually subsides within two or three weeks and is followed by muscle atrophy and severe weakness.

Twenty-nine-year old Lucy Schwartzman is participating in the HSS study. She clearly remembers the day in April of this year when she was struck by severe pain in her right shoulder that radiated into her neck and down her arm to her elbow. After a few weeks, the extreme pain improved, but she started to experience another problem. “Three weeks in, I went to fill up my water container and realized I couldn’t move my arm; I couldn’t reach forward,” she recalls. “I felt like my upper arm was paralyzed.” Ms. Schwartzman says she still can’t move her arm above her elbow, and it has affected her ability to perform basic activities, such as putting on a jacket or washing her hair.

“Patients experience damage to the peripheral nerves that control movement in the shoulders and arms,” explains Darryl Sneag, MD, director, Peripheral Nerve, MRI, at HSS and principal investigator. “In our study, we will use magnetic resonance neurography to obtain high resolution images of those nerves. Our goal is to discover biomarkers to detect and monitor PTS. We will also use ultrasound imaging and check patients’ blood for inflammatory markers.”

Parsonage-Turner Syndrome is named for Drs. Maurice Parsonage and John Aldren Turner, who described 136 cases in the Lancet medical journal in 1948. The disease is also called neuralgic amyotrophy or brachial neuritis.

Although the exact cause is not known, it is believed PTS may arise following a viral or bacterial infection, an injury, surgery, strenuous exercise or a medical procedure. There is no cure or specific treatment, although doctors usually prescribe pain medication, steroids and physical therapy to help relieve symptoms. Sometimes patients receive intravenous immunoglobulin.

Although an estimated 80 to 90 percent of people eventually recover and regain function of their arm, it could take several years. Full strength may not return for some patients, and a certain number will continue to experience mild pain.

The discovery of a biomarker for PTS could pave the way for clinical trials to determine which treatment works best and open the possibility of finding new treatments down the road, according to Dr. Sneag.

“Our research aims to understand if imaging and serologic findings in PTS can serve as reliable, noninvasive markers of motor and functional recovery,” he notes. “In addition to facilitating clinical trials of possible treatments, early identification of the nerves affected by PTS could assist in determining if surgery could help patients.”

Previous PTS research by Dr. Sneag and colleagues identified a specific abnormality in brachial plexus branches and other peripheral nerves. “Using high-resolution MR neurography and ultrasound techniques, we have routinely identified one or more hourglass-like constrictions of nerves in patients with Parsonage-Turner Syndrome and have detected denervation changes in muscles they supply,” he explains. “The constrictions actually make the nerve look like an hourglass on the digital image. We perform almost 100 MR neurography cases monthly at HSS and have not seen this in any other nerve condition, so we believe these constrictions are unique to PTS.”

Patients enrolled in the new HSS study will have imaging tests at their initial consultation and at follow-up intervals of three, six and nine months. Dr. Sneag and colleagues hypothesize that a greater number of or more severe constrictions in affected nerves will correlate with worse muscle function and lower patient-reported outcome scores at each time interval. The MRI findings will be correlated with standard electromyography (EMG) tests that measure muscle function and the nerves that control them.

Using imaging to zero in on hourglass-like constrictions in affected nerves also aids in surgical planning, according to Dr. Sneag. “Images obtained by magnetic resonance neurography can enable surgeons to do a very targeted surgery. Instead of exploring the entire nerve in an arm, the images can pinpoint the location of the constriction,” he says. “Think of a coaxial cable. When you cut it, you see a cross section of multiple fibers. In a damaged nerve, constrictions may not involve the entire nerve, but just one or more fibers within the nerve. With MRN showing the exact location of the constriction, the surgeon wouldn’t have to spend hours opening and exploring the nerve to find it.”

The National Center for Advancing Translational Sciences of the NIH awarded the $275,000 grant for the HSS study, which is expected to take two years. Investigators are recruiting patients 18 and older who have been diagnosed with Parsonage-Turner Syndrome. Anyone interested in participating is invited to email Sophie Queler at quelers@hss.edu or call (646) 714-6242 for more information.

Dr. Sneag explains that peripheral nerve imaging is somewhat of a biomarker and can help treat complex conditions such as Parsonage-Turner Syndrome. "Biomarkers that can identify specific diseases and place patients into categories can better direct treatment. We want to know precisely what we are treating. An objective diagnosis through imaging can also help with longitudinal monitoring to see how nerves improve, or don't improve, over time."

When looking at the growing subfield of MR neurology, Dr. Carrino explains that not all readers are created equal. "There are specialized protocols we use at HSS that require interaction with other multidisciplinary providers for optimal outcomes. This involves understanding imaging and understanding the disease process—that specific interaction is key. I would advise pain providers to seek out professionals who really know how to image the peripheral nerves rather than sending patients to the closest or most convenient location, which may not result in the most accurate information."

Read the full article at PracticalPainManagement.com. This also appears in Volume 18, Issue #9.