Totally 685 LDH patients who underwent PELD in our hospital from January 2015 to December 2017 were enrolled in this study, including 397 males and 288 females, with mean age of 57.7±19.8 years (range 24–88 years). Among them, 351 cases had a history of smoking. Mean body mass index (BMI) was 22.6±5.5 kg/m2 (range, 17.3–36.8 kg/m2). The levels for herniated disc were L3/4 in 38 case, L4/5 in 374 cases, and L5/S1 in 273 cases. The types of disc herniation (MRI findings) included protrusion in 298 cases, extrusion in 279 cases, and sequestration in 108 cases. The position of herniated disc (MRI findings, including central to right sided and central to right sided protrusion/herniation) included the left-sided disc herniation in 385 cases and right-sided disc herniation in 300 cases. Mean follow-up time was 21.5 ± 4.7 months (range, 13–30 months).
The inclusion criteria were:(1)LDH was definitely diagnosed in patients in accordance with the patient’s medical history, physical signs, and imaging examination; (2) patients who obtained poor outcomes after systematic conservative treatment for more than 3 months; (3) patients who had no history of previous lumbar surgery; (4) patients who were followed up for more than 12 months; (5) patients who had no obvious contraindications to surgery; and (6) patients and their family members had good compliance, gave written informed consent to participate in study, and completed follow-up.
The exclusion criteriawere: (1) patients who had history of previous lumbar surgery; (2) patients or family members had poor compliance, did not agree to receive treatment and did not complete follow-up; (3) patients who had psychiatric diseases; (4) patients who had postoperative infection; and (5) patients who became pregnant after surgery.
Diagnostic criteria for recurrent LDH8-10
- Ipsilateral or contralateral radiculopathy symptoms occurred again after a symptom-free period of one week.
- Postoperative MRI reexamination indicated that the protruding nucleus pulposus tissue had been removed.
(3) MRI revealed reherniation at the same level (ipsilateral or contralateral), which caused nerve compression.
The operation was performed by senior doctors in the same group. Interlaminar approach was adopted in patients with LDH at the L5–S1 level with high iliac crest. PELD via transforaminal and interlaminar approaches were performed under local anesthesia and epidural anesthesia, respectively. All patients were placed in prone position. After conventional catheterization, the surgery was conducted under endoscope. Attention should be paid to protect the dura mater and nerve roots in order to avoid damage to the endplate. The ligaments and small joints were preserved as much as possible, and the sequestered nucleus pulposus and nucleus pulposus that caused symptoms were removed thoroughly. Simultaneously, thermal annuloplasty was carried out until the dura mater and nerve roots were decompressed completely. The wound was closed with a stitch after a complete hemostasis under the microscope. A drainage tube was placed in case of excessive bleeding. The drainage tube could be removed 1–2 days after operation depending on the amount of drainage.
Management after the first surgery
All patients received routine anti-infection and symptomatic treatments after surgery. Patients were allowed to get out of bed to perform moderate activity for 15–30 minutes under the protection of the waistline at 24 hours after surgery. After the symptoms relieved, patients were instructed to perform straight leg raising and lower back exercises. Improper waist postures, such as sitting or standing for a long time, bending down, and weight bearing, were avoided. A full rest was taken for three months, and physical labor was avoided within half a year. All patients in this study were followed up by outpatient appointment, telephone, and WeChat for 13–30 months.
Retreatment for recurrent LDH
For patients with recurrent LDH, retreatment options was selected according to the patients’ symptoms and MRI examination results. Patients with mild herniation and less pain (VAS score ≤ 3) were treated with conservative treatment or interventional therapy (radiofrequency ablation, ozone and collagenase chemonucleolysis). Patients with moderate and severe herniation and moderate and severe pain (VAS score ≥ 4) and without obvious lumbar instability underwent PELD again. Patients with moderate and severe herniation, a VAS score of ≥ 4 and lumbar instability were treated with spinal canal decompression by open posterior approach, discectomy, and screw rod system internal fixation with cage fusion.
(1) Recurrence rate; (2) visual analogue score (VAS) and Japanese Orthopaedic Association (JOA) score before the first surgery, after the recurrence and at the final follow-up; (3) postoperative activity levels that were scored with postoperative activity level scale (Table 1)11; (4) factors for recurrent LDH: age, sex, the levels for herniated disc, the types of disc herniation, the position of herniated disc and postoperative activity levels.
Measurement data were expressed as the mean ± standard deviation. All data were analyzed using SPSS 23.0 software. Count data were compared using chi-square test. Intergroup difference was compared using independent sample t test. Logistic regression analysis was used to analyze the factors with statistical significance in univariate analysis. A P value < 0.05 was considered statistically significant, and P < 0.01 was deemed highly significant.