Lumbar spinal surgery, where have we gone?

Lumbar spine surgery is, by and large, still one of the most controversial topics in American medicine, especially among neurosurgeons and orthopedic surgeons. Two articles, recently published nearly side by side in The Spine Journal, addressed 2 issues surrounding lumbar spinal surgery. In the first article, entitled “Predicting outcome in the surgical treatment of lumbar radiculopathy using the Pain Drawing Score, McGill Short Form Pain Questionnaire, and risk factors including psychosocial issues and axial joint pain,” Voorhies, Jiang, and Thomas have provided a compelling prospective study of 110 patients who, yet again, demonstrate the negative effects of psychiatric and psychosocial conditions on the outcome of lumbar spinal decompression surgery, in this instance for a single root entrapment [19]. Noteworthy is the degree to which psychosocial and psychiatric disorders affect outcome, which has not been well documented in the past. This study shows that there was no probability of an excellent or good outcome, in the scale of excellent, good, fair, and poor, based on the Prolo outcome score [14], in the presence of a psychiatric factor or personal injury claim, and only a 23% possibility when there was a workers' compensation case. Who would buy anything with odds like that, leave alone a major back operation? This is not new information for surgeons, however. A study published in 1995 on such surgery noted that in patients with workers' compensation issues, only 16 (25%) of the 64 patients treated with laminectomy and diskectomy alone had a satisfactory result, which included return to work [2].

Also, although it is generally common knowledge among surgeons that axial joint pain is not treatable with decompression of a nerve root, this study finds that in the face of significant axial pain, the chances of obtaining an excellent or good outcome altogether was only 27%, although the primary purpose of the surgery was decompression of a single nerve root that was clinically entrapped. Again, it is a dismal outcome even when there was clinical evidence of nerve root irritation or entrapment.

The Pain Drawing has not been used before in such a prospective and follow-up study on decompression surgery but was in this instance using the Ransford method of scoring [15]. When the drawing was scored 3 or more, the chance of an excellent or good outcome was reduced to 55%. The McGill Short Form Sensory and Affective questionnaires were also used [12], and with a sensory score of 17 or more or an affective score of 7 or more, the chances of an excellent or good outcome were reduced to 50% and 42%, respectively. Because psychosocial and psychiatric factors play such an important role in the outcome of lumbar surgery, why are these factors not evaluated routinely by surgeons? No really good answer is forthcoming, but the time needed for such an evaluation and the added expense are anecdotally mentioned by surgical colleagues. The Minnesota Multiphasic Personality Inventory (MMPI) is a quite accurate test, repeatedly documented, that would uncover most, if not all, such negative psychological issues but is rarely used by surgeons. It usually takes up to an hour of time to answer the many questions on the test, although they are all true-false and requires a psychologist to interpret unless the surgeon wants to take the time to learn how to score and read it, so the effort required is an impediment. The Pain Drawing and the McGill Short Form Pain Questionnaire, which has only 11 sensory questions and 3 affective questions, have been suggested as a convenient alternative. Indeed, using these brief, moderately effective tests will at least weed out a number of patients who will benefit poorly from surgery as shown in this study. But as the authors of the study point out, those tests are not substitutes for an actual psychological investigation and therefore are not true alternatives to such. The lesson still to be learned is that, when one is operating on a patient for pain only or mostly, an adequate psychological analysis is a necessity and is not just a luxury. I have been the medical director of a comprehensive interdisciplinary pain treatment center for 30 years. Our center is regularly referred patients who have undergone lumbar surgery and failed to obtain pain relief. I have yet to see a single such patient who has undergone either psychological investigation or taken the MMPI, McGill Questionnaire, or Pain Drawing before having lumbar surgery that failed, even in spite of obvious psychosocial issues such as litigation and workman's compensation prevalent in the case.

Another important result of the study was the manifest difference of outcome rating as measured by the surgeon and the patient, shown in the (Fig. 1) below taken from the article.

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Fig. 1. Drawing Score, McGill Short Form Pain Questionnaire, and risk factors including pychosocial issues and axial joint pain. Reprinted with permission from The Spine Journal 2007;7:516-524.

The differences noted, particularly the skew in the excellent category and the low ratings by the surgeons in the fair and poor categories, are remarkable. The difference becomes even more important because in a prospective study, everyone in the study, surgeon and patient alike, are aware that the study is being conducted. These differences also reflect heavily on the objectivity of other studies on similar types of surgeries reported in the literature when the outcome of surgery is determined by the surgeon alone.

Fusion vs laminectomy alone in the treatment of painful lumbar degenerative conditions is also a hotly disputed topic among spine surgeons. The second lumbar study from the same issue of The Spine Journal, last year, on lumbar fusions, analyzed regional variations of charges and complications in the United States [5]. The authors found that lumbar fusion surgeries in the South and West resulted in lower percentages of routine discharges, higher levels of cauda equina complications, and higher charges for the surgical period. Findings of the Northeast and the Midwest indicated the highest length of stay (LOS), both in median and average, but similar vascular, infectious, and cardiopulmonary complications, fewer cauda equina complications, and fewer overall charges. Although the LOS of the Northeast was the highest, the overall charges and, for the most part, complications were the lowest. These authors further point out that the proportion of lumbar fusion surgeries to overall lumbar surgeries was previously reported but identifying higher proportions of surgical fusion in the South and Midwest and lesser proportions in the Northeast and West [16], [7]. Past studies have also shown surgeons in the West performed the least amount of spine fusion surgeries, in spite of most amount of stenosis surgery is carried out there [4]. Furthermore, lumbar surgery rates vary even within states. For instance, there was a statistically significant variation in lumbar surgery rates reported among regions in the state of Utah, with the highest region having a rate 50% greater than the lowest region, and of note, there was no correlation between those different rates with the number of surgeons available [13]. These findings highlight the lack of agreement about when lumbar fusion should be recommended. In this day of rapid and readily available communications electronically, and with the residency review committees presumably keeping training programs relatively uniform, and with surgeons freely communicating and continuing to learn through national meetings and other continuing medical educational requirements, it is hard to understand and harder even to justify such remarkable variations in surgical care. These local variations notwithstanding, internationally, the United States has higher rates of back surgery than any other country, showing 5 times the rate of surgery of England and Scotland [3]. Why? The lay press has suggested monetary reward as a reason because surgeons are paid by Medicare for a lumbar fusion at least 4 times the amount for a laminectomy [1], and of course, Medicare rates pretty well are used to set the rates of payment by many insurance companies and essentially all managed-care payers.

The foregoing may also reflect why lumbar fusion rates have increased dramatically in the decade of the 1990s, a time when managed care grew dramatically with the consequent payment reduction for laminectomy. For instance, in 1992, the Medicare costs for lumbar fusion represented 14% of total spending for back surgery, and by 2003, the rate was 47% [17]. Lumbar fusions in general increased 134% during the same decade [6]. The increase came in spite of no good scientific evidence exists that fusion of the lumbar spine has been demonstrated superior to the alternative nonsurgical treatment of degenerative conditions. The most recent Cochrane review of spinal fusion notes: “Two new trials on the effectiveness of fusion showed conflicting results. One showed that fusion gave better clinical outcomes than conventional physiotherapy, while the other showed that fusion was no better than a modern exercise and rehabilitation programme” [10]. In such a prospective study comparing lumbar fusion surgery to rehabilitation, it was concluded that both groups reported reductions in disability during 2 years of follow-up, which the authors admitted could be possibly even be unrelated to the interventions, but no clear evidence emerged that primary spinal fusion surgery was any more beneficial than intensive rehabilitation [9]. Intensive rehabilitation is considerably different than conventional physiotherapy, which the Cochrane study indicated did not do as well as fusion surgery. Even when there is evidence of degenerative spondylolisthesis in spinal stenosis cases, simple laminectomy alone has been demonstrated to provide excellent or good outcome in 82% of cases using the Prolo outcome score. In a long-term follow-up, only 2.7% of patients required a later fusion [8]. At this time, a prospective randomized multicenter study is ongoing that compares simple laminectomy vs instrumented fusion in cases of spinal stenosis with spondylolisthesis and a 2-year follow-up [11]. The outcome may influence future decision making on this subject but there is already sufficient good scientific data to refute the use of lumbar fusion on a regular basis.

So, what is the bottom line? Surgeons clearly need to use some form of psychological consultative help before deciding to electively operate on the low back, even when the clinical indications are there and especially when some obvious psychosocial issue is present. Fusion in degenerative conditions should be reserved for the situation where there is a clear indication, documented instability. Perhaps some form of guideline review should be implemented as is done in the state of Washington for compensation cases [18]. No one likes to be regulated, but in this era of science-based medicine and of the newer concept of outcome-based payment reward, such may happen if we do not police ourselves.