This study identifies the authors and topics that have had the most impact on the field of lumbar spine surgery during the course of the last century and the beginning of this century. Through the identification of these classic works, we gain an insight into the history, development, and current trends in lumbar spine surgery. The findings of this study identify the papers responsible for many important developments in this field.
Similarly, the second most referenced study was a radiographical study of degenerative disc disease findings in asymptomatic individuals. In this study by Jensen et al,9 98 asymptomatic patients underwent lumbar spine MRI, with 52% having a bulge at 1 level, 26% having a protrusion, and 1% having a disc extrusion. The paper noted an increased amount of disc bulges with aging and the relatively common finding of a Schmorl node, a herniation of nucleus pulposus through the bony and cartilaginous endplate into the vertebral body. This paper aimed to correlate LBP with disc pathology, concluding “bulges or protrusions in people with low back pain may frequently be coincidental.”
Three of the authors were credited with 4 or more publications. Deyo was the most prolific of all of the authors on the top 100 list. First author on 5 publications, his name appears as a contributing author on 9 of the top 100 papers. His papers focus on outcomes, quality of life, role of physical examination, surgical indications, and morbidity surrounding surgery in the lumbar spine. Boden had 4 works in the top 100 focusing on bone morphogenetic protein, spinal fusion, imaging for patients with LBP, and operative decision making for patients with herniated lumbar discs. Weinstein focused on operative decision making, spinal stenosis, and trends of spinal surgery over time. Interestingly, in 2006, all 3 of the aforementioned most prolific authors contributed to 1 study, the SPORT (Spine Patient Outcomes Research Trial) study (28th most cited article). In this study that spanned 13 spine clinics in 11 states, patients with sciatica from lumbar disc herniation were divided into standard discectomy versus usual nonoperative care groups. The intent-to-treat analyses showed that improvements were in favor of surgery but were small and not statistically significant for the primary outcomes.
Of the top cited papers, only 4 were published before 1980. Previous studies have suggested that older papers are more likely to be cited.116 However, this may be misleading due to the phenomenon of “obliteration by incorporation,” the process whereby data from truly classic papers are cited less frequently as they are absorbed into the body of current knowledge.111 In this study, the journal Spine produced the largest number of articles in the top 100 list. It must be noted that when evaluating contributions by various journals, those journals with bimonthly publications and those that have been in circulation for the longest time have more chance of being cited by other authors.
This study has several limitations. Although Thomson Reuters Web of Knowledge helped identify commonly cited lumbar spine surgery papers, it was difficult to determine the true “lead” author of each paper. For this reason, the first author was assumed to be the primary contributor to the work and this was used to create the ranking of authors according to the number of publications. Another limitation to this study is the problem of “incomplete citing,” which is described as the erroneous manner in which some citations are made in an effort to convince or persuade the readership of that particular journal, instead of giving credit to those who most significantly influenced the work. Using the impact factor as a marker for quality and rank of a journal is a possible limitation of our study. The impact factor is published annually by Thomson Reuters and is broadly based on the number of citations for a given journal. It is frequently used as an indicator of the importance of a journal to its field (although it should not be used as an indicator of a specific article's significance). The strengths and weakness of the impact factor have been discussed widely in the literature. One notable weakness is the short time frame (2 yr) that is factored into its calculation, putting fields that take longer to accumulate citations at a disadvantage.117 Another weakness is the inclusion of noncitable items in the calculation for the impact factor, including letters, book reviews, and news items.118 Eugene Garfield, the man who created the impact factor, stated that although it “is not a perfect tool to measure the quality of articles ... there is nothing better ... and is, therefore, a good technique for scientific evaluation.”119 Another limitation is the subjective nature of choosing which papers are relevant to include in the top 100 list and which should be excluded because of irrelevance to lumbar spine surgery. Finally, because the key word “lumbar spine surgery” was searched, it is possible that important contributions were missed if they did not include this specific word used for the database query, constituting another weakness.
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