Diskography in the Popular Press

Reed Murtagh

Now good medical writing isn’t limited to specialty journals; one can learn important information about AIDS from an article in Rolling Stone, Creutzfeldt-Jacob disease from Scientific American, and Alzheimer disease from Time. The Sunday New York Times runs a feature on chronic fatigue syndrome and then expands it into a book. The Wall Street Journal runs a front-page story on the latest anti-cancer drug, and although the article centers on business rather than scientific issues, it underscores the public’s concern with medical news. The medical feature article is a sign of our times, from which physicians may be as likely to get updated information on disease and therapies as their patients. Patients can learn of a scientific breakthroughs before physicians if physicians don’t have broad enough reading habits. The physician no longer has exclusive access to medical knowledge.

In this editorial, I am turning the tables on the popular press by reviewing a medical feature article that addresses the controversial and complicated subject of low back pain. “A Knife in the Back,” by Jerome Groopman, appeared in The New Yorker in the April 8, 2002, issue (http://www.newyorker.com). The subtitle, “Is surgery the best approach to chronic back pain?” tips the author’s hand, but few physicians would be inclined to disagree with him. The long-held, official position of the North American Spine Society (NASS) is a strong recommendation for initial conservative therapy for any onset of low back pain that does not include significant neurologic deficit. This conservative approach includes the widespread practice of postponing MR imaging until after an unsuccessful 6-week course of medical treatment. It should be emphasized, however, that for a patient with significant neurologic deficit, the NASS recommends immediate MR imaging and, if necessary, surgery. The rare patients with low back pain and loss of bowel or bladder control because of a large extruded free disk fragment should undergo immediate surgery.

Patients with acute low back pain may have an extruded disk compressing or irritating nerve roots or they may have a flare-up of degenerative arthritis. Patients with chronic low back pain may have arthritis or instability. Most patients with acute or chronic low back pain do not have serious neurologic deficits and will respond well to nonsteroidal or steroidal anti-inflammatory medications combined with an appropriate regimen of physical therapy. Most patients do not need to undergo diskectomy for acute low back pain, and, if conservative therapy is going to alleviate symptoms, they may not need to undergo fusion surgery for chronic pain either. In the New Yorker article, Dr. Groopman carefully distinguishes this majority of patients with low back pain from the much smaller group who do require immediate surgery for major neurologic defects, unstable fractures, epidural tumor, or spinal cord tumor.

It is appropriate for Dr. Groopman to question why 150,000 spine fusion operations were performed in the United States last year when uncertainty persists whether the procedure is effective or necessary. His inclusion of approximate reimbursement schedules for spine surgery casts a shadow of innuendo regarding motivations for recommending surgery, which may or may not be relevant information when reviewing number of procedures performed. Groopman often veers from objective analysis; however, he makes a good case for a conservative therapeutic approach to low back pain.

Dr. Groopman follows a patient with low back pain from onset to postoperative outcome and his description of a surgical fusion operation in another patient is told in gruesome detail. What is notable, however, is that he devotes comparable space a diskography procedure performed in the former patient before surgery, as he does to the fusion procedure in the latter patient. One not trained in medicine and contemplating undergoing diskography, not to mention fusion surgery, might have second thoughts about both procedures after reading this article.

Although Dr. Groopman’s depiction of the diskography procedure evokes images of medieval torture, his description is, unfortunately, fairly accurate. Nonetheless, his reference to the “long metal table” on which the procedure was performed was unnecessarily suggestive of an autopsy table. His repetition of the word “trocar,” the needle inserted into the patient’s back, appears to be a rhetorical device designed to make this needle sound like a harpoon, amplifying the patient’s agony when the physician inserts the instrument into her lower back.

Proceeding with the clinical details, Dr. Groopman chronicles that when an intervertebral disk is injected, the patient “gasps” in pain. We as neuroradiologists know that the diskogram is probably concordant with the patient’s symptoms, and we know that this pain lasts only an instant; Groopman omits that information and as a result the pain lingers in the reader’s mind. The radiologist’s seeming lack of empathy is remitted when he asserts that diskography is his least enjoyable procedure because “patients are intentionally subjected to pain.” Then Dr. Groopman launches an accusation: “The results of diskographymay be dangerously misleading.” Of course, the results of any diagnostic study can be misleading when in the wrong hands. If a patient reacts in a strongly positive way to injection of disks at every level tested, the performing physician has an obligation to ask why. Is the patient experiencing pain at every level or is this patient’s sensitivity an indication of a somatization disorder? Or, is this attributable to flawed technique? As with any procedure, diskography is tinctured with subjectivity; the perception of the performing physician and that of the patient cannot be corroborated, quantified, or reproduced by a third party. Despite the complexities surrounding diskography, an attempt to objectify the patient’s response is important and should be recorded as accurately as possible.

Neuroradiologists have come some distance since the American College of Radiology, in a 1978 position paper, stated that diskography was useless. It is possible that more neuroradiologists today than in 1978 would allow that scrupulously performed and selectively applied diskography, in cases in which all other diagnostic findings are equivocal, is useful for revealing a painful disk level. Unfortunately, no researcher has yet been able to confirm this with any long-term, scientifically controlled, reproducible investigation. Many of the long-term, large-cohort studies of diskography in the current scientific literature are flawed, including those cited in Dr. Groopman’s article. Most of these investigations cannot be found in the radiology literature but rather in orthopedic or neurosurgical spine journals, even when radiologists author them. With few notable exceptions, radiologists and neuroradiologists have either been too busy condemning or too busy performing diskography to prove unquestionably whether it is worth doing.

In The New Yorker, Dr. Groopman not only notes that diskography is controversial but shares the same opinion of all the other aspects of the diagnosis and surgical therapy for low back pain, including the interpretation of MR images, the diagnosis of spinal instability, and the rationale for fusing vertebrae. He correctly implies that all these are controversial, even among spine specialists, implying that diskography is an art rather than a science.

It is probably true that diskography in the wrong hands can be used to support a preconceived notion about the significance of a disk abnormality seen on an MR image (eg, the fabled “black disk”). That is why it is best to have an objective physician, ideally a trained radiologist, perform diskography and convey objective information to the treating physician in a manner unbiased by any clinical features except the patient’s isolated reaction during the procedure. The treating clinician should not perform the diagnostic study, just as the clinician should avoid interpreting his or her own diagnostic studies, such as MR imaging findings of the spine. Objectivity is imperative when assessing a disease entity that has so many subjective features.

Objectivity is what the diagnostic radiologist or neuroradiologist brings to the diskogram table. If we are going to be performing more diskography procedures, we must show in our literature that there is a valid use for this often maligned procedure and that it can be helpful in decisions related to the treatment of low back pain, even in the face of doubts expressed in the popular press.