Risk Factors and Causes of Reoperation in Lumbar Disc Herniation Patients after Percutaneous Endoscopic Lumbar Discectomy: A Retrospective Case Series with a Minimum 2-Year Follow-Up

Abstract

BACKGROUND Percutaneous endoscopic lumbar discectomy (PELD) has gained popularity as a minimally invasive surgery for treating lumbar disc herniation. However, there is limited research focusing on the reoperation rate and its associated factors. This study aims to investigate the rate of reoperation and identify the causes and risk factors for reoperation after PELD. MATERIAL AND METHODS We conducted a retrospective analysis of patients who underwent PELD (interlaminar and transforaminal approaches) at our hospital from November 2016 to May 2020. A matched case-control design was employed to identify relevant risk factors for reoperation, with a matching ratio of 1:3. Clinical characteristics and radiological parameters were compared, and univariate analysis was performed using independent samples t-test and chi-squared test. RESULTS Among the 435 patients included in the study, the reoperation rate for those with a minimum 2-year follow-up was 6.2% (27/435). The causes of reoperation and their respective rates were as follows: recurrence of lumbar disc herniation (3.2%, 14/435), incomplete decompression (1.8%, 8/435), persistent low back pain (0.7%, 3/435), and postoperative infection (0.5%, 2/435). Univariate analysis revealed that age (P=0.015), Pfirrmann grade IV-V (P=0.017), and lack of active straight leg raise exercises (P=0.026) were significantly associated with reoperation. Multiple logistic regression analysis indicated that age (P=0.001), Pfirrmann grade IV-V (P=0.033), and lack of active straight leg raise exercises postoperatively (P=0.003) were independent risk factors for reoperation after PELD. CONCLUSIONS The primary cause of reoperation in lumbar disc herniation patients after PELD was recurrence of the herniation. Additionally, severe disc degeneration, older age, and lack of active straight leg raise exercises were identified as significant risk factors associated with an increased reoperation rate.

Figure 1

Measurement of the DHI: The height of the anterior a), middle b), and posterior c) intervertebral space and the sagittal diameter of the overlying vertebral body d) were measured. DHI=[(a+b+c)/3]/d.

Figure 2

Measurement of the ECA: On the sagittal X-ray of the lumbar spine, the bone endplate of lumbar vertebra is in arc shape, and a line was drawn from the summit/bottom of arc along to the endpoints, and the angle between these 2 lines is defined as the ECA.

Figure 3

Measurement of the sROM: (A, B) The sROM can be calculated by the difference between flexion and extension angles, which was measured in relation to the lines of the superior and inferior endplate of the surgical level. The patient sROM is 9.8 degrees at L4–L5 in this patient.

Figure 4

(A, B) Preoperative MRI scan shows the segment of lumbar disc herniation at L5-S1 (red arrow). (C) The working channels of interlaminar approach. (D) The decompressed nerve root under endoscopic view (white arrow). (F, F) Three years later, MRI reexamination showed the herniated disc on the right side at level L5-S1 with severely foraminal stenosis (red arrow). (G, H) X-ray examination of lumbar vertebrae after reoperation.

Figure 5

A 57-year-old man with severe right leg radiating pain for 6 months. (A, B) Preoperative MRI scan shows the segment of lumbar disc herniation at L4–L5 (red arrow). (C, D) The working channels of transforaminal approach during the first PELD. (E, F) MRI reexamination at 1 month after the first PELD. The red arrow indicates residual intervertebral disc tissue. (G, H) The working channels of interlaminar approach. (I, J) MRI reexamination showed the dural sac was well-filled and there was no compression of nerve roots after reoperation (red arrow).