Because the main problem varies across recovery stages after PELD, this study developed a staged rehabilitation programme that differed by the period after surgery. The results indicated that the patients in the staged group exhibited significantly improved low back pain and lumbar spine function in 6th and 12th weeks, and the programme promoted patient recovery from the surgery. At 12th week, the left-right support phase ratio of gait was significantly higher in the staged group than in the regular group; at 24th week, the results of the low back pain and lumbar spine function evaluation were similar between the two groups, but the staged group was relatively healthier, and the CSA of the multifidus muscle in the surgical segment was nonsignficantly larger, showing that the application of the staged rehabilitation programme yielded an efficient clinical effect.
Functional units of the spine (passive system), paravertebral muscle system (active system) and neuromuscular control system (regulatory system) work together to execute spine-related movements. Coordinated control of the human spine and extremity kinetic chain is the key to normal motor function [21, 22]. The theory of spine rehabilitation, which emphasizes the overall movement of the spine, is reasonably suitable for postoperative rehabilitation to improve surgical efficacy, reduce postoperative complications and the severity of pain, maximally restore patients’ physical function .
McKenzie therapy is a widely recognized nonsurgical treatment for low back pain [18, 24], especially by physical therapists. In some countries, this therapy is designated as a standardized rehabilitation programme for chronic low back pain [25, 26]. The basic principles of McKenzie therapy for low back pain are to return the joints of the spine to the neutral position through special posture training and exercise and to return the disc to the central position of the intervertebral space, avoiding movements or postures that push the intervertebral disc toward the edge [18, 27]. In theory, this treatment can prevent the recurrence of LDH in the surgical segment after PELD and the degeneration of the adjacent segment, biomechanically aligning the spine with the human body.
The core of the human body is defined as the lumbar-pelvic-hip complex, which is where all movement in the body begins, and 29 muscles are connected to this complex . Effective core strength facilitates optimal kinematic performance of the functional motor chain, providing neuromuscular efficiency throughout the chain and proximal stability during lower extremity movement. Good human core strength also provides normal dynamic stability to generate forces and counteract abnormal stresses. When the nucleus pulposus is removed, it is likely that lumbar facet joints and the ligamentum flavum are partly excised during PELD, which inevitably leads to altered kinematics of the overall kinetic chain and a reduced ability to counter abnormal external forces. Therefore, maintaining kinetic chain coordination as much as possible through core muscle strengthening exercises is an important remedy and the most effective type of functional exercise. Several studies have clearly demonstrated that core stability training can improve the symptoms of chronic low back pain and prevent the recurrence of low back pain [28–30]. The results of this study confirmed that the CSA of the surgical segmental multifidus muscle increases at 24 weeks of staged rehabilitation; although the change was not statistically significant, it helped to improve the core stability of the body.
Patients with LDH often present with pelvic kinetic dysfunction, which causes gait abnormalities [15, 16]. Pelvic kinematics and lumbopelvic rhythms are used to evaluate the mechanisms by which LDH causes gait abnormalities. Changes in pelvic posture occur with anterior, posterior, coronal tilt and horizontal rotation of the lumbar spine and hip joint. Patients with herniated discs experience anterior pelvic tilt to prevent the nucleus pulposus from moving backward. The lumbopelvic rhythm responds to the sagittal flexion of the lumbar spine and hip joints during trunk movement from upright to flexed, and vice versa. Patients with LDH exhibit compensatory pelvic motion due to abnormal lumbar curvatures or pain and thus eventually exhibit gait abnormalities. This study showed abnormalities in the bilateral leg support ratio during gait, and after 12 weeks of staged rehabilitation, this gait abnormality was effectively corrected. This finding confirms that pelvic lower extremity dysfunction after LDH is of great significance.
Early rehabilitation after PELD is mainly conducted to promote healing of the tissues around the surgical site, enable standing as early as possible with waist support, and prevent early complications, such as venous thrombosis of the lower extremities. In this study, both groups underwent the same type of rehabilitation for 2 weeks postoperatively, which was in accordance with the medical ethics guidelines. When the patients were discharged from the hospital, the two groups began to undergo strict staged rehabilitation or regular rehabilitation, respectively. Significant improvements in low back pain, lumbar spine function and ability to perform activities of daily living were found in the staged group at the 6th and 12th weeks postoperatively. Early and targeted postoperative rehabilitation improves surgical efficacy, improves symptoms, and promotes the recovery of physical function. At 24th weeks postoperatively, there was improvement in pain and lumbar function in both groups, but only the SF-36 score in the staged group improved significantly. Both groups of patients underwent rehabilitation exercises, and after 6 months of rehabilitation, the patients recovered from surgical trauma, which allowed the body to reorganize its structure and function in daily life. Staged rehabilitation was targeted more, with more systematic exercises of the lumbar, abdominal, and back muscles, and patients exhibited better recovery of core strength, greater adaptability and better SF-36 scores. Thus, staged rehabilitation is important not only to promote symptomatic improvement and functional recovery after surgery but also to help patients relearn proper movement patterns. There were even some patients who exhibited higher levels of athletic performance after staged rehabilitation than before surgery.
In this preliminary study, only a sample size of 60 patients were included. In the future, multicentre randomized controlled studies with larger sample sizes should be conducted. Carrying out staged rehabilitation and medium- and long-term follow-ups in the community or at home would improve the cost-effectiveness of the programme.Although rehabilitation protocols are consistent in same group and instructors received unified training, there may be differences in understanding and implementation by patients. The only gait analysis parameter was the ratio of the left to the right supporting phase, and muscle mechanics of the lower extremities were not assessed. The core muscle strength of the lumbar region should be evaluated in future studies.