Effect of time to first ambulation on recurrence after PELD

Inclusion criteria include the following: (a) unilateral or bilateral lower extremity pain with or without low back pain; (b) nerve root symptoms such as abnormal sensations in the lower extremities, positive straight leg elevation test, and positive reinforcement test; (c) diagnosis of single-segment lumbar intervertebral disc herniation by computed tomography (CT) and magnetic resonance imaging (MRI) (Fig. 3c–f); (d) failed of standard conservative treatment for 3 months; and (e) PELD operation and follow-up for more than 3 months.

Exclusion criteria include the following: (a) vertebral instability and spinal stenosis; (b) cauda equina syndrome; (c) lumbar spine fracture, tumor, or active infection in the surgical area; and (d) other systemic diseases that do not allow the patient to tolerate surgery.

Ninety patients were treated with PELD and were divided into three groups according to the time they initially got out of bed: early (group E), middle (group M), and late (group L). There were 15 males and 17 females in group E, with an average age of 40.81 ± 11.82. L3/4, L4/5, and L5/S1 lesions were found in 3, 28, and 1 patients, respectively. In group M, there were 16 males and 14 females, with an average age of 39.20 ± 10.97. The L3/4, L4/5, and L5/S1 lesions were found in 4, 25, and 1 patients, respectively. In group L, there were 15 males and 13 females, with an average age of 37.46 ± 10.83. The L3/4, L4/5, and L5/S1 lesions were found in 3, 23, and 2 patients, respectively. Prior to the operation, all patients underwent anteroposterior and lateral lumbar X-ray, CT, and MRI scans.

All operations were performed under local anesthesia and monitoring. The patient was placed in a prone position on a special bed for fluoroscopic spine injection with the abdomen suspended. The median line of the spinous process and the contour line of the iliac bone were marked on the surface of the body prior to the operation. A line parallel to the surgical puncture intervertebral disc was determined by fluoroscopy with the guidance of a C-arm X-ray machine. An 8–14-cm line was marked parallel along the posterior median line of the spine on the operative side, and the head was tilted to the side along the horizontal line of the intervertebral space under the guidance of an anteroposterior projection. The intersection between the oblique line through the intervertebral foramen and the parallel line between the intervertebral space was the puncture point. After local infiltration, anesthesia was administered with 1% lidocaine on the skin, and in the superficial fascia at the puncture point, the puncture needle was inserted slowly into the shoulder of the superior articular process of the lower vertebral body under fluoroscopic guidance. Then, local infiltration anesthesia was administered to the articular process joints, the core of the needle was withdrawn, the guide wire was inserted through the puncture needle, an approximately 7 mm incision was made in the skin, and the expansion sleeve and ring saw were inserted step by step along the guide wire with the use of a mirror. Under endoscopy, nucleus pulposus forceps were used to grasp the soft tissue on the surface of the articular process, the bone was exposed, and the articular process bone was rotated with a circular saw. The sawed bone was completely removed with the circular saw and was inserted into a working cannula through the sawed space (Fig. 1 g, h). The yellow ligament on the dorsal side of the nerve root and dural sac was grasped under endoscopy, and dorsal decompression was performed. After decompression, the working cannula was moved to the lateral and ventral sides of the nerve root. A second fluoroscopy showed that the tip of the cannula did not exceed the line of the spinous process and that the lateral position did not exceed the line of the posterior edge of the vertebral body. The protruding nucleus pulposus was removed under endoscopy to expose the nerve root and dural sac (Fig. 1i). In areas with ossification, the nerve root could be treated by a grinding drill and reverse curettage, and the entrance and exit of the nerve root could be loosened throughout until the dural sac pulsated with the patient’s breath and the nerve root relaxed completely without compression. Bipolar radiofrequency ablation was carefully used to stop the bleeding and suture the skin. Anti-infection, dehydration, and detumescence agents were given as appropriate after the operation.

According to the time to first ambulation after the operation, the patients were divided into three groups: group E (3–24 h), group M (24–72 h), and group L (3–7 days). Many patients who wake up early after PELD will tell us that they feel pain around the wound and that they feel sore in their backs after a long walk. Therefore, we will inform patients that PELD is a minimally invasive operation, and they can become active the next day after surgery. Of course, they can also choose to extend their bed rest as needed, but to no more than 7 days. Finally, the time until getting out of bed was determined by the patient him- or herself. The specific time that the patient got out of bed was recorded (Figs. 2 and 3).

All patients were followed up for at least 3 months. The visual analog scale (VAS) and Oswestry disability index (ODI) scores before the operation, at first ambulation, 1 month after the operation, and 3 months after the operation; recurrence rates; and incidence rates of high MRI signal in the vertebral endplate area were recorded after operation.

The data were analyzed by SPSS 23.0 software, and the measurement data were expressed as the mean ± standard. Paired t tests were used for intragroup comparisons, variance analyses were used for intergroup comparisons, and chi-square tests were used for counting data. The difference was considered statistically significant at P < 0.05.

All patients in the three groups were successfully operated on under local anesthesia. The postoperative CT showed that the prominent nucleus pulposus was removed, the intervertebral foramen was decompressed adequately, and the dural sac was not compressed (Fig. 1). None of the patients experienced any serious complications, such as nerve root injury, cauda equina syndrome, intervertebral discitis, hematoma, or wound infection. There were no significant differences in age, sex, preoperative VAS scores of low back pain and leg pain, preoperative ODI, operation time, and bleeding volume among the three groups (Table 1). There were significant differences in hospital stay among the three groups (Table 1), mainly due to the difference in postoperative bed rest time, that is, the time until first walk after operation.

The VAS scores of low back pain and leg pain in the three groups significantly improved at first ambulation after the operation compared with those before the operation (t = 21.13, 7.67, 9.43, P < 0.05) (Table 2), but there were no significant differences among the three groups (F = 1.169, P = 0.316) (Table 3). The VAS scores of low back pain in group E at 1 and 3 months after the operation (2.56 ± 1.11, 2.44 ± 1.56) were significantly higher than those in the other two groups (group M 1.30 ± 1.02, 0.50 ± 0.82; group L 0.82 ± 0.77, 0.21 ± 0.79) (F = 25.454, P < 0.05; F = 34.932, P < 0.05) (Table 3, Fig. 4a). The VAS scores of leg pain at first ambulation after the operation in group E were significantly higher than those in the other two groups (F = 3.600, P = 0.031). However, at 1 and 3 months after the operation, there were no significant differences in the VAS scores of leg pain among the three groups (F = 2.596, P = 0.080; F = 2.550, P = 0.084) (Table 4, Fig. 4b).

The ODI scores of the three groups improved significantly at first ambulation after the operation (Table 2). At first ambulation and at 1 and 3 months after the operation, the ODI scores of group L were significantly better than those of the other two groups (Table 5, Fig. 4c).

MRI with T2-weighted imaging (T2WI) and fat-suppression sequences displayed that the following proportions of intervertebral discs or endplates had higher signal bands 3 months after the operation than before the operation: 37.50% (group E), 13.33% (group M), and 3.57% (group L). There were significant differences among the three groups (Table 6, Fig. 4d). Because the high signal area occurred in the disc or endplate area and was still present at review 3 months after surgery, these findings were probably due to an inflammatory response, and the possibility of hematomas was small. There were four cases of recurrence in group E, and the recurrence rate was 12.5%. There were no recurrences in the other two groups. The recurrence rate was significantly different among the three groups (Table 7).