The Pain Physician, Pain, Pain Medicine, Regional Anesthesia and Pain Medicine, and Journal of Pain are peer-reviewed journals invested in understanding and developing new clinical practices to alleviate the elevated economic burden of pain today, namely chronic pain. This is confirmed by more literature showing an increase in the prevalence of chronic pain among United States patients. [10] (Table 8).

The Pain Physician is a journal with over two decades of publications and 6 issues per year since 2007 and has a journal impact factor of 4.396. Pain Physician is the official publication of the American Society of Interventional Pain Physicians (ASIPP). Pain is another journal publishing since 1975. It is the official publication of the International Association for the Study of Pain (IASP). Pain has a journal impact factor of 7.926. Pain Medicine has been publishing journals since 2000 as the official publication of the American Academy of Pain Medicine (AAPM). This journal has an impact factor of 3.637. Regional Anesthesia and Pain Medicine (RAPM), with a journal impact factor of 5.564 is the official publication for the American Society of Regional Anesthesia and Pain Medicine (ASRA). Lastly, Journal of Pain, the official journal of the U.S. Association for the Study of Pain (USASP), has an impact factor of 5.383. All of the above journals are open access with their main objectives to continue the pursuit in knowledge and treatment of various types of pain.

Citation analysis was also performed to compare articles from these five journals based on their CY scores. Of note, articles that had the highest overall citation number may not have been placed highest concerning CY score. If an article had a higher citation count over a shorter period, this would boost the CY score and, therefore have it higher on our CY ranking list.

Our first CY ranked article was titled “The revised International Association for the Study of Pain definition of pain: concepts, challenges, and compromises.” It was cited 1356 times and was released in 2020 with a CY score of 4452. It was published within Pain. The senior author is Dr. Srinivasa Raja, MD. He is a professor of Anesthesiology and Neurology and the Director of Pain research at Johns Hopkins University School of Medicine. His interests lie in the management of chronic neuropathic pain states and he recently put his work into understanding the peripheral and central mechanisms of neuropathic pain. The article is a review that provides dialogue and discussions of the revised definitions of pain according to the IASP council. The current definition of pain at the time of publishing was “An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.” The new revision is “An unpleasant sensory and emotional experience associated with, or resembling that associated with actual or potential tissue damage.” The task force used multiple models, including monthly web-web discussions, and in-person meetings to arrive at the new pain criteria. The public consultation was also acknowledged. 808 responses from 46 countries, including clinicians, clinical and basic science researchers, administrators, educators or trainees/students, were submitted. [11•].

The second most cited article was “Central sensitization: Implications for the diagnosis and treatment of pain”. It had 2867 total citations and was published in 2019. It had a CY score of 238.9, making it third in our CY rank. It was also published with Pain in 2011. Published by Dr. Clifford J. Woolf, M.B., B. Ch., PhD, he is affiliated with F.M. Kirby Neurobiology Center and the Neurobiology program at Boston Children’s Hospital. His research interests are investigating the functional, chemical, and structural plasticity of neurons that contribute to adaptive and maladaptive changes, focusing specifically on pain in the injured and neurodegenerative conditions. In the article, Dr. Woolf discusses central sensitization, its history and its role in neurodegenerative pathologies such as rheumatoid arthritis, osteoarthritis, temporomandibular disorders, fibromyalgia and more. He describes this pain as being caused by central sensitization due to the “increased state of excitability”. He states there is much more to be learned about central sensitization including genetic and molecular mechanisms that may contribute to chronic pain in some individuals. [12].

The article with the second CY rank is “Chronic pain as a symptom or a disease: the IASP Classification of Chronic Pain for the International Classification of Diseases (ICD-11)”. It had 1246 total citations and was published in 2019 with a CY score of 311.5. The senior author is Dr. Rolf-Detlef Treede MD, PhD, Chair of Neurophysiology at the Mannheim Center for Translational Neuroscience in Mannheim, Germany. Dr. Treede specifically researches damaging stimuli to the nervous system and its relationship to acute and chronic pain. He also works to develop tools to assess nociceptive pathways. In this article, Dr. Treede et al. presents a systematic classification of chronic pain that is part of the ICD-11 chronic pain diagnosis. This classification was lacking in ICD, causing significant confusion in treatment pathways for chronic pain patients. In collaboration with IASP and the World Health Organization (WHO), a new classification system was created to apply for specialized pain management. Chronic pain now serves as the “parent code” for seven other codes that are made up of the most common clinical pain conditions, including chronic primary pain, chronic cancer-related pain, chronic postsurgical or posttraumatic pain, chronic neuropathic pain, chronic secondary headache or orofacial pain, chronic secondary visceral pain and chronic secondary musculoskeletal pain. [13•].

The most cited article was at CY rank 13 with 5452 citations. Published in 1975 through Pain, titled “The McGill Pain Questionnaire: Major properties and scoring methods”. Authored by Dr. Ronald Melzack, PhD, Canadian psychologist and professor of psychology at McGill University, he introduces the McGill Pain Questionnaire. In it, he describes how to use the questionnaire and what to gather from the results. His three main measures are the pain rating index, number of words chosen and present pain intensity. Dr. Melzack also provides analysis of a research project that uses the McGill Questionnaire, revealing that the pain rating index was an objective method to report differences in pain with various treatments in research. [14].

Our analysis found a total of 83 senior authors contributing to the top 100 most cited articles published across all 5 journals. The most published senior author was Dr. Laxmaiah Manchikanti, MD. Dr. Manchikanti founded the American Society of Interventional Pain Physicians (ASIPP), the Society of Interventional Pain Management Surgery Centers (SIPMS) and the Pain Physician. Dr. Rolf-Detlef Treede, Dr. Johan W.S. Vlaeyen, Dr. Nanna Finnerup, Dr. Didier Bouhassira, and Dr. Robert N. Harden each had 3 articles. Combined, these senior authors contributed to 19 total articles.

There are five types of scientific evidence: case reports/case series, case–control studies, cohort studies, randomized control trials and systematic reviews. However, with the number of articles which could not be categorized under these evidence types, new study types had to be used in addition. 40 of the articles were narrative reviews, which included studies such as basic science, review articles and literature reviews. 17 articles were meta-analysis and systematic reviews, followed by 16 experimental trial articles. Experimental trials included experimental or observational studies, clinical trials, and randomized control trials. Practice guidelines included between-subject and scale development studies (9 total). There were 8 survey studies which included prevalence studies. Comparative studies had 6 total articles. 3 articles were editorials and 1 article was a retrospective cohort. There were no prospective cohort, case–control or case-reports/case series studies. With the increasing prevalence of pain by almost 10% from 2002–2018, the need to understand the multidimensional aspects becomes vital for improving care and reducing healthcare costs. [15] The escalating prevalence and amount of information on these two types of pain states makes it increasingly difficult to keep up with all the data provided. To alleviate this burden on the scientific community, authors have and continue to compile original research articles to analyze, to summarize, and to critique them in newly synthesized review articles. [16] As expected, most of the top 100 cited articles were Level I and II studies, which indicates the strength of the evidence provided with Level I being based on strong experimental designs and studies. Examples can include RCT’s, systematic reviews of RCT’s and can include meta-analyses. Level V is the opposite end of the scale and is based on experiences and non-research evidence. While useful, Level V evidence should not be completely ignored just as Level I evidence should not be considered entirely generalized. [17, 18].

With the growing prevalence of chronic pain and back pain, a predictable increase in the number of articles detailing the medical, economic, and social strains caused by them and the need for multidisciplinary pain management strategies to alleviate those strains has been observed. [18] Compared to the other types of pain analyzed in this study, chronic pain was the most researched among all journals. A recent study on the prevalence of chronic pain among adults in the US states that 50.2 million (20.5%) of the population reported pain on most days or every day. [19].

In the present study, we found that review articles were the most common type of study related to chronic pain. These literature reviews can be utilized to establish a base of knowledge, call attention to research gaps, and pave the path for future practices.