Feasibility of Recurrent Herniation Surgery with Biportal Endoscopic Discectomy : A Comparison of Biportal Endoscopic Discectomy and Microscopic Discectomy for Recurrent Disc Herniation

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J Korean Neurosurg Soc. 2026;69(2):231-237

Publication date (electronic) : 2026 February 5

doi : https://doi.org/10.3340/jkns.2025.0083

Sang Youp Han¹, Sang Hyub Lee¹, Jae-Won Jang¹, Dong-Geun Lee¹, Yong Eun Cho¹, Choon-Keun Park¹, Il Sup Kim^,2

¹Department of Neurosurgery, Spine Center, The Leon Wiltse Memorial Hospital, Suwon, Korea

²Department of Neurosurgery, St. Vincent’s Hospital, The Catholic University of Korea, Suwon, Korea

Address for correspondence : Il Sup Kim Department of Neurosurgery, St. Vincent’s Hospital, The Catholic University of Korea, 93 Jungbu-daero, Paldal-gu, Suwon 16247, Korea Tel : +82-31-249-8207, E-mail : nsman72@hanmail.net

Received 2025 April 14; Revised 2025 July 27; Accepted 2025 September 6.

Abstract

INTRODUCTION

Several studies have demonstrated the advantages of unilateral biportal endoscopic (UBE) surgery. This endoscopic discectomy reduces postoperative pain, due to small wounds, and complications such as incidental durotomy and neural injury during surgery with good surgical vision [10]. Although our study did not consider quantitative measures for assessing these advantages, our clinical experience is consistent with these previously reported benefits. In addition, postoperative instability is prevented by preserving the lumbar posterior columns with less infection after surgery. However, few studies have investigated the benefits of biportal endoscopic revision discectomy.

Several studies comparing surgery through revision percutaneous endoscopic lumbar discectomy (PELD) and microscopic discectomy (MD) showed the numerous benefits of PELD [1,8]. However, few studies have compared the clinical outcomes of UBE and MD. To address this knowledge gap, in the present study, we compared the serial pain outcomes in patients who underwent UBE and MD and compared the associated complications and recurrence rates.

MATERIALS AND METHODS

This study was approved by the Institutional Review Board of Wiltse Memorial Hospital (approval No. 2023-W09).

RESULTS

Patients

Ninety patients were enrolled in this study, of whom 44 underwent UBE and 46 underwent MD. The mean age of the patient’s undergoing UBE was 48.9 years old (28 men and 16 women; range, 26–79), and that of the patients treated with MD was 52.2 years old (31 men and 15 women; range, 30–88), showing almost the same pattern. The most common surgical level in both groups was L4/5 (UBE, 61.3%; MD, 67.3%). The mean follow-up periods were 19.09±10.22 in the UBE group and 20.45±7.79 in the MD group (p<0.001). All surgeries were performed from March 2020 to April 2023. Demographic data is presented in Table 1.

Table 1.

Demographic data of the UBE and MD groups

Clinical outcomes

The mean operation time was similar in both groups (UBE, 107.2±33.8 minutes; MD, 107.9±23.4 minutes; p=0.960). However, the hospital length of stay was significantly shorter in the UBE group than in the MD group (UBE, 4.57±2.84 days; MD, 7.0±3.91 days, p=0.001). The bleeding loss was also shorter in the UBE group (UBE, 34.09±20.75 mL; MD, 41.82±24.13 mL; p=0.057); however, the difference was statistically insignificant.

There was no statistically significant difference in preoperative pain between the groups. However, immediately postoperative back pain was significantly lower in the UBE group compared with the MD group (VAS score : UBE, 3.32±0.91; MD, 7.89±1.06; p<0.001). In addition, the number of painkillers used on the day of surgery was significantly higher in the MD group compared with the UBE group (MD, 1.66±1.22; UBE, 1.36±0.84; p<0.001). This difference in back pain persisted until discharge. However, from 1 month postoperatively onward, no significant difference between the two groups was found. Radiating leg pain substantially improved in both groups postoperatively, however, no statistically significant difference was found between them (Table 2 and Fig. 1).

Table 2.

Preoperative and postoperative VAS scores in the UBE and MD groups

Fig. 1.

Preoperative and postoperative VAS score. VAS : Visual analog scale, UBE : unilateral biportal endoscopic, MD : microdiscectomy, POD : postoperative day, F/U : follow-up.

Recurrence and complications

Recurrence after surgery was classified as either early or late (with 14 days as the cutoff). Early recurrence occurred in one case in the UBE group and two cases in the MD group. Late recurrence occurred in one patient in the UBE group (postoperative day 6 months) and twice in one patient in the MD group (5 and 18 months postoperatively). Patients in the UBE group underwent fusion surgery, and those in the MD group underwent MD twice. The overall recurrence rates were 4.55% and 8.7% in the UBE and MD groups, respectively (Table 3).

Table 3.

Postoperative recurrence in the UBE and MD groups

Dural tears occurred in three and four patients in the UBE and MD groups, respectively. In all cases, the patients recovered after conservative treatment using primary sutures. In addition, the UBE group was treated with peroral antibiotics and resutured because of the occurrence of wound dehiscence in two cases. The MD group underwent aspiration and re-suture due to the occurrence of wound dehiscence in one patient, while hematoma removal was performed due to postoperative hematoma. No major complications such as wound infection or nerve tissue damage occurred in any of the patients (Table 4).

Table 4.

Postoperative complications in the UBE and MD groups

DISCUSSION

Recurrent disc herniation is a common complication after lumbar discectomy, occurring in 5–18% of patients [2,4,5,6,7,18,19]. In addition, the rate of surgical treatment of recurrent disc herniation is quite high at approximately 62% [3,13,17]. Of note, the results of revision lumbar discectomy have been reported to be favorable [9,22]. However, patients may experience discomfort during the process.

In addition, revision surgery for recurrent disc herniation is more difficult and associated with a higher rate of complications than virgin surgery. Scar tissue usually makes repeat microscopic discectomy more difficult and increases the risk of dural tears and/or nerve root injury [1,4,6,12,16,20,21]. The incidence of dural tears during repeat microscopic discectomy has been reported in up to 20% of patients [4,15]. Experienced surgeons can also perform durotomy when performing adhesiolysis. Durotomy increases hospital stay, while central nervous system infection can cause fatal problems. In addition, maintaining absolute bed rest or lumbar drain insertion for durotomy causes discomfort among patients. However, surgery using an endoscope can reduce patient discomfort, lower the complication rate by magnifying surgical vision, and reduce posterior column damage [8]. Lee et al. [14] previously reported that the complication rate was lower when revision surgery was performed using PELD (4%) compared with MD (10.3%). Although PELD and UBE differ in their approach and technical characteristics, both are minimally invasive endoscopic techniques. Therefore, the findings from PELD may offer supportive context regarding the potential benefits of endoscopic revision surgery. In addition, in that study, two cases of durotomy occurred only in the MD revision group (PELD 0% vs. MD 6.9%), further suggesting the value of enhanced visualization during endoscopic techniques. Kang et al. [11] reported that UBE revision surgery provided faster pain relief and earlier functional recovery than did MD revision surgery. This study also showed that the immediately postoperative outcome tended to be better in the UBE group than in the MD group; however, the difference was not statistically significant. Moreover, the results of long-term follow-up beyond 6 weeks were similar between the two groups.

Additionally, incidental durotomy was less frequent in the UBE group (6.8% vs. 8.7%), but this difference did not reach statistical significance, likely owing to the small sample size.

UBE may offer a wider surgical field of view compared with microscopic techniques, potentially reducing the risk of incidental durotomy by allowing better visualization of anatomical structures. In addition, when MD is performed, venous bleeding may occur; the surgical field of view may be obscured as there is no venous bleeding due to water pressure with UBE. This technique also has the advantage of keeping the surgical field clean (Fig. 2). However, if a durotomy is performed during UBE surgery, serious problems can arise. When water flows into the durotomy site, the intracranial pressure increases, causing neurological deterioration. Symptoms such as seizures or mental deterioration may occur. As such, completing the operation as soon as possible if a durotomy occurs is necessary. Furthermore, the surgical method should be changed to conventional microscopic discectomy if the operation is prolonged.

Fig. 2.

Comparison of the field of view between the MD and UBE revision surgeries. MD : microdiscectomy, UBE : unilateral biportal endoscopic.

Neural tissue damage is another potential complication during revision surgery. Since the ligamentum flavum had already been removed, the neural tissue is immediately exposed without protection. Neural tissue damage can occur when a mistake is made during the bone drilling process or when a punch is used. However, improvements in the field of view can reduce the likelihood of neural damage; as such, UBE is associated with a lower risk of neural damage because the nerves are sunken due to water pressure.

Based on our experience, paraspinal muscle dissection and adhesiolysis were not technically challenging during UBE revision surgery. This may be attributed to the effects of continuous water pressure and minimally invasive nature of the UBE technique, which reduces the need for extensive soft tissue manipulation. Furthermore, continuous irrigation also helps reduce thermal injury during endoscopic procedures.

The third major complication during revision surgery involves wound problems, including infection, hematoma, and dehiscence, which may necessitate reoperation and prolonged antibiotics. With smaller incisions and less muscle dissection, UBE may reduce such wound-related risks. In our center, such complications were infrequent and manageable in patients who underwent endoscopic surgery; however, the difference was not statistically significant.

The UBE revision group experienced less postoperative pain compared with the MD group, with a trend toward better back pain observed before discharge. The number of analgesics administered on the day of surgery was significantly lower in the UBE group. Improvement in radiculopathy was similarly significant in both groups immediately after surgery. However, there were no differences in terms of long-term follow-up (more than 1 month), as back pain and radiculopathy both improved without differences between the two groups.

Recurrence was higher in the MD group, though this difference did not reach statistical significance, likely owing to the small sample size. However, in the MD group, one patient experienced two recurrences at 5 and 18 months. Although the exact cause is unknown, it can be assumed that there will be an impact on instability due to repeated posterior column injuries such as paraspinal muscle, facet, and wide laminectomies [11].

This study has several limitations, including its retrospective design, the small sample size from a single center, and the relatively short and uneven follow-up periods between groups. In addition, the lack of randomization may have introduced a degree of selection bias, despite the comparable proficiency of all participating surgeons. These factors should be considered when interpreting the results. Further prospective, multi-center randomized controlled trials are warranted to validate our findings. Given these limitations, the present findings should be interpreted as exploratory rather than confirmatory. The potential benefits of UBE observed in this study should be interpreted with caution and require validation in broader clinical contexts.

CONCLUSION

UBE revision discectomy had several advantages, including ease of securing the surgical field of view and preservation of the posterior column, which may contribute to lower immediate postoperative pain. Although the UBE group showed a smaller surgical wound and numerically fewer wound-related problems and recurrences, these differences were not statistically significant. Thus, the present study suggests that endoscopic revision discectomy could be considered a potential alternative to MD; however, further studies are needed to confirm these findings.

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