Lumbar disc herniation (LDH) is a complex and variable pathological process, with displacement occurring in multiple directions, including cephalad and caudal. Research on the direction of LDH displacement has been controversial, with varying data reported by different research teams. Studies by Igarashi and Daghighi found that the proportion of cephalad and caudal displacements was 27.8% and 72.2%, respectively, and noted a significant increase in the incidence of cephalad displacement in the upper lumbar discs of elderly patients, possibly related to changes in the anterior epidural space (AES) and sedentary lifestyles[3, 4]. In contrast, Ahn et al. reported different proportions of 46.53% and 53.47%, but did not reach a similar conclusion [5]. Lee et al. reported that cephalad displacement of LDH (Grade 1 + 2) accounted for only 3.5%, significantly lower than other grades[6]. Furthermore, Ahn et al. reported that surgical LDH cases were most common in Grade 4, followed by Grade 5 and Grade 1 [2]. However, Ahn's data only indicated a higher surgical rate for extremely cephalad LDH (Grade 1) and did not accurately reflect the proportion of LDH direction and severity. These differences primarily stem from variations in sample size and research methods.
Although all existing studies have yet to provide precise ratios or significant differences in the age distribution of head lateral displacement, they have broadly mentioned the prevalence of this phenomenon among elderly patients and have accordingly put forward corresponding theoretical support. Notably, the occurrence in this young patient case suggests that young individuals may also be susceptible to this condition. Therefore, it is crucial to give sufficient attention to lumbar health in young people, especially those in high-risk groups such as those with occupations requiring prolonged sitting, obesity, and poor trunk muscle strength and condition.
AES refers to the narrow space between the dura mater and the bony membrane of the vertebral canal as well as the posterior longitudinal ligament. Igarashi et al. found that the AES at the L2–L3 segment is relatively spacious, and the fatty tissue within the space tends to atrophy with age. These factors contribute to the higher incidence of cephalad displacement of lumbar discs in elderly individuals. Additionally, sedentary behavior in the elderly weakens the effect of gravity on herniated material, increasing the pressure within the spinal canal, which may facilitate cephalad displacement of herniated disc tissue [3]. Besides age and lifestyle, factors such as trunk muscle status [7], intervertebral stress distribution [8], and anatomical variations[9]also have direct impacts, further complicating the direction of LDH displacement. However, as this young patient presented with LDH in the lower lumbar spine, we may need to further explore other potential pathogenic mechanisms.
In terms of diagnosis, although leg and back pain are common symptoms of LDH, they are not essential for diagnosis. MRI is the preferred imaging modality, capable of clearly demonstrating LDH. However, due to specific conditions such as ring enhancement, MRI results may lead to diagnostic difficulties. Therefore, a comprehensive evaluation combining clinical symptoms, signs, and imaging examinations is necessary for diagnosis.
Regarding treatment, traditional Chinese medicine (TCM) physiotherapy and Western surgical interventions have their respective advantages. TCM massage and myofascial manipulation can regulate the body, relax muscles, strengthen bones, prevent muscle atrophy, improve lumbar flexibility, adjust local muscle tension, and increase spinal stability, thereby preventing the occurrence or recurrence of LDH [7]. Meanwhile, healthy lifestyles, such as avoiding prolonged sitting, enhancing exercise, and strengthening lumbar and back muscle exercises, can benefit LDH patients [10]. Hu et al. reported sequestered lumbar disc herniation can regress within a relatively short timeframe without surgery[11].
In Western medicine, advances in techniques and instrumentation have gradually shifted LDH surgery from open procedures to minimally invasive approaches. Percutaneous endoscopic discectomy is currently a safe and effective minimally invasive surgical method, but it is not suitable for all patients. Lee and YU et al. argue that minimally invasive surgery for highly cephalad displaced LDH may face challenges such as anatomical barriers and the risk of nerve injury, which may prevent complete resection of the herniated material [6, 12]. Therefore, when selecting a surgical approach, it is essential to fully consider the patient's specific condition and surgical risks. Although this patient was not definitively diagnosed preoperatively and underwent open surgery, intraoperative difficulties in retracting the dural sac were encountered. Nevertheless, complete resection of the herniated lumbar disc material was achieved after decompression by releasing cerebrospinal fluid, demonstrating the effectiveness of the surgery.
In summary, lumbar disc herniation and displacement represent a complex yet intriguing research field, with numerous unknowns awaiting further exploration. Through rigorous research and the accumulation of practical experience, we can gain a deeper understanding of this condition and optimize its management, ultimately enhancing therapeutic outcomes and quality of life for patients. Additionally, it is imperative to enhance public health education, particularly among younger individuals, to raise awareness and understanding of lumbar health, which holds significant importance in preventing the occurrence of lumbar disc prolapse and related disorders.