Cervical spondylotic myelopathy (CSM) is a progressive degenerative disease of the cervical spine leading to static and repeated dynamic cord compression. It is the most common cause of spinal cord dysfunction in quinquagenarians and beyond. It is also the predominant cause of atraumatic spinal cord injury [1]. The management, research, and overall understanding of CSM continue to evolve as our understanding of the disease, mechanisms, pathogenesis, and treatment options improves.

In the international literature, magnetic resonance imaging (MRI)-based population studies have revealed that more than 85% of adults aged above 60 years have severe degeneration of at least one cervical level. Most patients are usually asymptomatic because of the lower incidence of radiculopathy and myelopathy and the average age at diagnosis is about 64 years. CSM is more prevalent in men than in women (ratio of 2.7:1) [2]. A door-to-door survey in a Sicilian municipality found the prevalence of cervical spondylotic radiculopathy to be 3.5 per 1,000 population, with a peak in the 50–59-year-old age group [3]. Nouri et al. [4] performed a narrative review and concluded that the incidence and prevalence of CSM were about 41 and 605, respectively, per 1,000,000 population in North America. Unfortunately, we were unable to find studies documenting the incidence and prevalence of CSM in different parts of Southeast Asia.

The etiopathogenesis of CSM is multifactorial, involving static factors like congenital cervical spine stenosis, disk protrusion, vertebral deformity, osteophytes, hypertrophy of ligamentum flavum, and ossification of posterior longitudinal ligament causing cord compression, along with dynamic factors such as hypermobility of the spinal cord leading to repetitive trauma [1].

The presentation of CSM is variable and involves sensory, motor, and autonomous systems to different extents among affected individuals [4]. The symptoms and signs are usually insidious in onset and may involve loss of hand dexterity, weakness of upper limb and lower limb musculature, gait disorder, urinary symptoms, neck pain, arm pain, decrease in mobility of the neck, paresthesia in arm, and loss of touch and proprioception [4]. The signs associated with myelopathic changes may be resolved after successful surgery.

The diagnosis of CSM is based predominantly on clinical assessment and MRI findings [5]. Surgery for CSM involves decompression of the spinal cord by expansion of the spinal canal by an anterior, posterior, or combined approach [6,7]. The anterior approach includes anterior cervical discectomy or corpectomy along with fusion, and cervical arthroplasty. The posterior approach includes laminoplasty or a laminectomy with or without fusion [5].

Conservative management, which includes immobilization of the neck using a cervical collar, lifestyle modification, and pharmacological interventions, among others, has little role in stopping disease progression or reversing it [5].

Bibliometric analysis is an exploratory method to identify research directions, clarify the evolution of a research field, and identify collaborative nodes in terms of institutions, countries, and primary initiatives that have driven the research using statistical and modeling techniques [8–10]. It also provides useful cues to funding agencies to identify priority areas and help in directing grants. Bibliometric methods can mostly be divided into two groups: evaluative and relational [11–13]. In evaluative methods, the impact of research work, authors, and so on is evaluated using productivity measures (e.g., the number of papers published per year), impact metrics (e.g., the number of citations per year), and hybrid metrics (e.g., h-index). In relational techniques, the relationships among various entities such as authors, publications, countries, and research fields are explored. Recently, Sinha et al. [14] analyzed the top 100 publications in the field of cervical myelopathy based on the number of citations. They concentrated their efforts on the most influential and highly cited articles. Our study on clinical studies of CSM was established to collect, compile, and analyze the last 50 years of data and research based on scientific bibliometric analysis. We employed evaluative and relational methods for mapping the overview of the evolution of the literature and recommendations on this entity, along with identifying the top cited papers, the predominant journals, and the networks of countries, institutions, collaborators, and authors, as well as various similar parameters.

The results of the performance mapping and science mapping are presented below.

CSM is one of the most important degenerative diseases related to the spine. While its importance clinically cannot be disputed, a comprehensive scientometric analysis of the research provides interesting insights, such as on the most influential authors, documents, countries, shifting trends, author collaborative networks, and co-occurrence of conceptual terms. First, we observed that there were more articles in Scopus than in PubMed. This could be attributed to the fact that Scopus also includes records from Medline and EMBASE databases, among other sources, and has more than double the number of records of PubMed [44].

The increasing number of publications each year shows increasing interest in this field of study among researchers. The steep decline in 2020 could have been due to coronavirus disease 2019 and subsequent lockdowns, which may have restricted the access to infrastructure and resources required to conduct research. This may be in part attributable to problems with scheduled follow-ups. The analysis of the importance of journals in terms of citations and h-index reveals that Spine is a leading journal among the research community, along with European Spine Journal, Journal of Neurosurgery, and Spine, as observed in both databases.

From the h-index and number of publications produced, Fehlings MG emerges as the top author as per both PubMed and Scopus data, although the absolute number of publications differs between the two databases. The country-wise data reveal that the majority of the published and highly cited works are from the United States, but Canada tops the list in terms of collaboration. Developing countries contributed less among the published results as well the collaborative networks, which may have been because of the need to deal with different research limitations, restricted resources, and lack of opportunities. This is despite the presence of a larger proportion of patients in these countries, so more results, research, and collaborations from these countries are awaited.

The trend analysis according to the frequency of words in publications showed some interesting findings. For example, less invasive and motion-preserving procedures are a new focus of interest, as is the management of CSM. Surgence of objective evaluation through scales, advanced radiological investigations including MRI, advanced nonoperative management including electric stimulation therapy are showcasing the relevant time trends. Fig. 5B reveals the gradual evolution of complex, more physiological motion-preserving, less invasive surgical procedures, and the refinement and advancement of diagnostic modalities.

The conceptual structure of the publications shows that the words present in cluster 2 represent the demographics, etiopathogenesis, symptomatology, and management options, focusing predominantly on the nonoperative options (Fig. 6A). Cluster 1 with the terms “arthroplasty,” “neck pain,” “intervertebral disc displacement,” and “discectomy” represents the pathology, symptoms, and newer treatment options of CSM. Cluster 3 represents a spectrum of analogous clinical conditions lower down the vertebral column. Similarly, in Scopus data, two important clusters can be observed (Fig. 6B). Cluster 1 includes terms such as “intervertebral discectomy,” “neck disability index,” “cervicobrachial neuralgia,” and “visual analog scale,” which encompass the symptomatology, scientific-scale-based objective evaluation of symptoms, and surgical removal of the offending culprit (i.e., disc). Cluster 2 includes the terms “computer-assisted tomography,” “decompression,” “laminoplasty,” “NMR,” and “stenosis,” broadly covering the patho-etiology, diagnostic modalities of relevance, and the surgery commonly performed for CSM.

Changing patterns in key areas of research (internal fixation to cervical disc replacement) indicate a gradual shift from fusion to segment and motion-sparing procedures.

This work constitutes a vivid presentation of the trends and evolution of CSM over the last 5 decades, which is expected to be useful for researchers and clinicians alike who want to promote research in this field.