A breakthrough in the evaluation and treatment of chronic neck pain and whiplash-associated disorders

Editor’s note:
I promised that AAOS Now would give AAOS members a place to “sound off,” just as Dr. Gorski is doing in this column. Readers are welcome to respond, comment, or critize, as long as you remember that AAOS Now is a “member” publication—not a scientific, peer-reviewed journal. Whether you think Dr. Gorski is ahead of his time or way off base, if there is referred pain from the neck to the shoulder, then I guess it is possible to have referred pain from the shoulder to the neck. (Some nerves, like the median nerve at the wrist, can “go uphill” [proximal pain].) As I recall, I was one of those who said total hips would not work!

Not long after the introduction of the Model T, the term “whiplash” was coined. In the decades since, researchers have never been able to prove the existence of the condition, which affects millions of unhappy patients. Chronic neck pain and whiplash-associated disorders continue to cost up to $20 billion annually, without any hope for a cure…perhaps until now.

Whiplash is not a favorite subject of orthopaedic surgeons, principally because a pathologic lesion has never been found in the neck. We can understand the whiplash mechanism resulting from acceleration/deceleration forces acting on the head and neck in a rear-end collision. We note that the number of whiplash claims continues to increase, despite modern head restraints, seat belts, and airbags. We are disappointed and perplexed when patients don’t improve after surgery. Without a defined neck lesion, we frequently defer the treatment of these patients to others. Every conceivable anatomic structure in the neck has been repeatedly scrutinized for the whiplash lesion and it just doesn’t exist—in the neck.

I think whiplash exists, and this is my hypothesis: No pathologic lesion has been found in the neck because whiplash—and most intractable chronic neck pain—is due to a shoulder problem. The pathologic lesion is asymptomatic shoulder impingement that presents as “neck” pain. In other words, whiplash is a shoulder—not a neck—condition!

More than semantics
The first problem with whiplash and chronic neck pain is largely semantic. The most common “neck” pain is not in the neck, but in the upper back between the neck and the shoulder, and frequently over the supraspinatus muscle. Pain in the upper back may also be ascribed to trapezius spasms, trigger points, thoracic outlet syndrome, and fibromyalgia.

When I see a patient with neck pain localized to the supraspinatus muscle in the upper back, I consider a new referred pain syndrome I call the Referred Shoulder Impingement Syndrome (RSIS), which I first described in the Journal of Bone and Joint Surgery in 2003.¹ Patients with whiplash, whiplash-associated disorders, or intractable chronic neck pain frequently have pain here, which my physician’s assistant has named the “G-spot” in my honor.

The second problem is that the shoulder is asymptomatic for many of these patients, and they may deny any shoulder problems. Yamaguchi has recently and definitively shown that shoulder impingement has both asymptomatic and symptomatic presentations.² He estimates that up to 17 million people have asymptomatic shoulder impingement, and I believe that many of them actually have RSIS, or neck pain referred from the shoulder.

Muddu³ and Chauhan⁴ have separately shown that the symptomatic shoulder impingement is associated with whiplash (“shoulder whiplash”), even suggesting this as a distinct clinical entity. My own research indicates that asymptomatic shoulder impingement is not only associated with, but frequently is, the underlying etiology in chronic neck pain and whiplash-associated disorders.

What’s behind it?
The pathophysiology of RSIS is largely speculative at this time. MacNab has histologically described the absence of pain fibers in impinged rotator cuff tissue, which may best explain the absence of shoulder complaints in the asymptomatic group.⁵ This finding is important and somewhat analogous to pressure sores. In chronic impingement, sustained pressure on the blood vessels and nerves of the rotator cuff causes them to become painless and asymptomatic in the shoulder.

I believe that the neck pain is due to pain and spasm in the adjoining supraspinatus muscle. When the shoulder hurts, the cuff is symptomatic, and perhaps some pain fibers are still present or the bursal tissues are painfully involved.

Don’t be surprised if you find yourself checking for RSIS in your own upper back; everyone seems to have this “neck” ache from time to time. The pain is ususally rated at about 3 on a visual analogue scale, on which 10 is maximum pain. For most people, it’s an annoying ache rather than a severe pain; for others, it is sometimes very severe. I think the associated limited neck motion may result from a compensatory reaction by the muscles around the supraspinatus. When patients bob their heads after a shoulder injection—I call it the “head dancing sign”—it is due to the immediate lessening of “neck” pain and spasm. It’s a great prognostic sign.

Don’t sleep on it
How does an insensated rotator cuff from sustained pressure or impingement develop without the patient’s being aware of it? The chronicity of the impingement is anecdotally correlated with a common sleep position in which the shoulder remains in the overhead position for prolonged periods “under the pillow.” Although my workers compensation patients deny it, everyone seems to sleep this way. I think this may also be the cause of the nightly sleep disturbances, tossing, turning, and the early morning complaints frequently reported by patients as having “slept funny” on their necks! I think every physician (and throwing/swimming coaches) should recommend avoiding this sleep position. We need much more research on the effect of sleep positions, but you can check it out for yourself tonight.

In my opinion, an acute shoulder injury commonly occurs in a car accident, especially if the driver continues to hold the steering wheel. It likely represents an acute injury to a chronically impinged shoulder if the patient habitually sleeps with the arm in the overhead position.

Furthermore, both the shoulder and neck are likely to be injured in any given accident, and the neck may be whipped back and forth, producing a soft-tissue sprain. In other words, the shoulder impingement likely accompanies a concomitant neck sprain. The neck sprain may subside, leaving the supraspinatus ache in the neck. This is aggravated when the patient sleeps with the arm overhead, resulting in persistent pain.

Making the diagnosis
If your patient winces with the arm overhead and complains of neck pain, suspect RSIS and consider a shoulder injection. In addition to using standard clinical diagnostic tests, the Neer impingement sign, and the Neer injection test to diagnose shoulder impingement, specific radiographic findings have proven essential, especially when the shoulder is asymptomatic. I believe that the radiographic finding of a pseudocyst in the proximal humerus is one key to the diagnosis (Fig. 1 on page 27). Its presence may give you enough reason to try injecting an asymptomatic shoulder.

The triad of a positive referred Neer sign (pain in the upper back with forward elevation of the shoulder), the radiographic pseudocyst, and the positive Neer injection test (relief of neck pain after a shoulder injection) can be used to diagnose RSIS.

The pseudocyst is real
The pseudocyst has been known since Codman’s day, but is rarely recognized and can only be understood along with RSIS. It is usually considered a normal variant or positional anomaly, and its presence is ignored, which is perhaps good considering its similarlity in appearance to a malignancy. But don’t biopsy this lesion! Because I often see the pseudocyst immediately after a motor vehicle accident, I believe it is present as an asymptomatic condition even before the accident. Pseudocysts are so common that I have extrapolated that RSIS is also common.

I think the pseudocyst is very real. It is not a cystic hole, but trabecular atrophy. I hypothesize that it results from increased retrograde blood circulation to the insertion of the rotator cuff into the greater tuberosity. When the rotator cuff is chronically impinged or traumatized, it becomes inflamed, edematous, and hyperemic. The increased blood flow causes demineralization and a radiolucent appearance on X-rays. Although an X-ray isn’t necessary to diagnose symptomatic shoulder impingement, it has helped me to make the diagnosis when the shoulder is asymptomatic.

If you find a pseudocyst in a patient who has chronic neck pain and an equivocally positive Neer sign, go ahead and inject the subacromial space with cortisone and lidocaine. I strongly recommend three injections over a period of 6 weeks to reliably relieve pain by 90 percent or more. Do not give just one injection and then operate when the symptoms recur, as I used to do. The use of three injections has been uncomplicated and will prevent the need for shoulder surgery. Physical therapy has not been required.

With this course of treatment, you will have very happy patients, especially if they suffered “whiplash” for years before being accurately diagnosed. Interestingly, one quarter of the patients I see have bilateral complaints, probably from sleeping with both arms overhead. Whether patients have unilateral or bilateral pain, advise them to avoid the overhead impingement position, especially while they are asleep. Prescribe a shoulder immobilizer to use at night, and ask if it is still on in the morning.

Ahead of my time?
It may appear oxymoronic to describe an aysmptomatic pain syndrome, and preposterous to propose both a pathologic lesion in the shoulder and shoulder treatment for neck pain and whiplash. Describing a new clinical entity in this contentious milieu is an uncertain and challenging process. As a pioneer of the anatomic medullary locking prosthesis and the S-ROM hip prosthesis under Charles A. Engh Sr., MD, and as an investigator who attempted to study bone morphogenic proteins in 1983—years before their use became accepted—I am well aware of how much time new hypotheses need to be tested, understood, and accepted. I expect that it will take a very long time for this new referred pain syndrome to be accepted as a “cure for whiplash” and chronic neck pain. But please don’t wait too long to try this; I predict that you and your patients will be amazed.

Jerrold M. Gorski, MD, is in private practice in Mineola, N.Y. He welcomes your feedback at jgorskimd@hotmail.com or through his Web site, www.gorskimd.com. Links to the studies cited in this article can be found online at www.aaos.org/now.

References

1. Gorski JM, Schwartz LH. Shoulder impingement presenting as neck pain. J Bone Joint Surg Am. 2003 Apr;85-A(4):635-8.
2. Yamaguchi K, Ditsios K, Middleton WD, Hildebolt CF, Galatz LM, Teefey SA. The demographic and morphological features of rotator cuff disease. A comparison of asymptomatic and symptomatic shoulders. J Bone Joint Surg Am. 2006 Aug;88(8):1699-704.
3. Muddu BN, Umaar R, Kim WY, Zenios M, Brett I, Sharma Y. Whiplash injury of the shoulder: is it a distinct clinical entity? Acta Orthop Belg. 2005 Aug;71(4):385-7.
4. Chauhan SK, Peckham T, Turner R. Impingement syndrome associated with whiplash injury. J Bone Joint Surg Br. 2003 Apr;85(3):408-10.
5. Macnab I, McCulloch J. Neck Ache and Shoulder Pain. Williams and Wilkens Co: Baltimore: 1983. p. 318-319.