Percutaneous endoscopic lumbar discectomy (PELD) has several advantages, but it is not used routinely due to early relapse and steep learning curve. We have studied the factors associated with early relapse in patients who underwent posterolateral PELD at or above the L4-5 level.
In this retrospective study, we have enrolled 200 cases and divided them into 4 groups (A, B, C, and D) with 50 patients in each group, that had undergone PELD by 2 different techniques (inside-out and outside-in with or without anti-adhesive agent) and operated by 2 different surgeons between May 2009 and November 2010. The factors studied were - Age, gender, disc (degeneration grade, location, level), associated adjacent level herniated nucleus pulposus (HNP), episode (first or recurrent), anti-adhesive agent, annulus preservation, approach, disc height and segmental dynamic motion (discrepancy in flexion and extension). Statistical analysis was done by Pearson’s chi-square test and p value (significance). The clinical results were evaluated by visual analogue scale (VAS).
The mean age and mean follow-up period was comparable in all four groups. The overall recurrence rate was 9.5% (19/200). Average early relapse time was 3.26 months. Factors like Age of the patient, multilevel HNP and degeneration grade showed significant correlation with relapse rate. The change in VAS pre-operatively to post-operatively was significant across all groups (p<0.001).
Based on the results of this study, high grade disc degeneration, multilevel disc herniation, and early postoperative activity are significantly associated with early relapse after PELD.
Since the time the first discectomy described by Mixter and Barr in 1934 [
Percutaneous endoscopic spine surgery of the lumbar spine has many advantages, but it has two problems: a long learning curve and early recurrence of herniation. Endoscopic removal of the lumbar disc herniation has been divided into interlaminar and posterolateral, which have different discal preparation methods and extraction forces, resulting in different types of relapse patterns. The purpose of this study was to investigate factors associated with early relapse in patients who underwent posterolateral percutaneous endoscopic lumbar discectomy (PELD) at or above the L4-5 level.
In this retrospective study, 200 cases were included who have undergone PELD by three different techniques (Inside-out and Outside-in with or without an anti-adhesive agent) and operated by 2 different surgeons between May 2009 and November 2010 (
Only disc herniations at L4-L5 or above were included, L5-S1 disc herniations were excluded as we prefer a percutaneous endoscopic interlaminar approach rather than the transforaminal approach in the L5-S1 HNP.
The patients were divided into 4 groups (
The factors included in relation to Disc Relapse were divided into 4 categories (
The disc degeneration scale was graded as per DeCandido classification [
The mean early relapse time was 3.26 months. Postoperative VAS was not significantly different between the four groups but a change in overall VAS in comparison to preoperative VAS was statistically significant (p<0.001). The anti-adhesive group (A and D) had a higher rate of early recurrence than the untreated group (B and C). There was no significant difference in recurrence rate between the two groups, B, and C i.e. between outside-in and inside-out approach (
Factors that showed correlation to early relapse were age, degeneration scale, combined HNP, anti-adhesive agent, disc location, disc level, and disc height but the statistically significant correlation was seen only with age of the patient, combined HNP and degeneration grade.
As for each factor, the patients within the age group of 40-60 years were most commonly affected. Hence with increasing age, the incidence of recurrence of herniation was greater (p=0.003) (
From our results, the relapse rate increased significantly with increase in the severity of degeneration (p=0.003) (
Patients with multiple HNP also showed significant correlation with early relapse following PELD (p=0.001) (
In the disc location, the relapse rate is relatively low in central, foraminal and far lateral in comparison to paracentral and migrated disc (superior and inferior) but the difference was not statistically significant. The most common level affected was an L4-5 disc (149/200) where 17 recurrences occurred. With increasing loss of disc height, there were more recurrences. Dynamic segmental instability along with disc height and disc level did not show statistically significant difference regarding recurrence of herniation.
The recurrence rate after microsurgical lumbar discectomy ranges from 5-15% in various studies [
Jensdottir M et al. reported a recurrence rate of 12.7% occurring 10-20 years after microsurgical discectomies. The mean time to recurrence was 5.9 years (1.3-19.7 years) [
As per Li X et al. where they compared PELD with a standard discectomy, there were no significant differences in VAS, MacNab criteria at the final follow up, complications, recurrence rate, and re-operation rate [
Many studies have described the risk factors for recurrence or relapse following open or microsurgical discectomy. Various estimated risk factors have been reported in the literature, such as age, gender, body mass index (BMI), smoking, herniation type, diabetes, and herniation level [
There are very few studies on risk factors for recurrence after PELD. To our knowledge, this is the first study to evaluate the risk factors like the role of anti-adhesive agent [
Both the surgeons in our study have been doing endoscopic surgery for more than 10 years, so surgeons experience is less likely to affect the outcome. Several surgical procedures and treatments have been introduced to prevent recurrence after open lumbar discectomy, and sequestrectomy has been reported to be effective. Barth M et al. concluded that sequestrectomy has demonstrated significantly less postoperative disc degeneration than standard microdiscectomy after 2 years and may thus represent an attractive treatment alternative [
In conclusion, the age, disc degeneration scale, and multilevel HNP are significant risk factors for early relapse. Chances of early recurrence after successful discectomy is common after PELD compared to the open lumbar discectomy. We should counsel the patient about early relapse in presence of high-grade disc degeneration at multiple levels. Moreover, absolute bed rest after percutaneous endoscopic lumbar discectomy for a few days will help in decreasing the early recurrence rate.
We would like to acknowledge scientific team members Ms. Jae Eun Park and Ms. Sol Lee for providing assistance in acquiring full-text articles and managing digital works.
Ⓐ Inside out technique: working cannula docked inside the disc. Ⓑ Outside in technique: working cannula docked to obtain half in and half out view of a disc.
Ⓐ, Ⓑ Pre-operative sagittal and axial MRI showing L4-L5 disc herniation. Disc degeneration seen predominantly in the L4-5 disc, rest of the discs are within normal limits.
Ⓐ, Ⓑ Immediate postoperative sagittal and axial MRI image after PELD.
Ⓐ, Ⓑ Recurrence of disc herniation after 3 months of PELD of the same patient as in figure 2 and 3, which operated with microscopic lumbar discectomy.
Ⓐ Sagittal MRI image of the lumbar spine shows multiple degenerated discs with a significant disc herniation at the L4-5 level. Ⓑ The Immediate postoperative sagittal image of the lumbar spine of the same patient showing disc fragment removal with adequate decompression. Ⓒ Sagittal MRI image of the same patient showing early recurrence at the one-month postoperative period.
Groups of patients with different surgical approaches and use of anti-adhesive agent
Group | Number | Approach | Anti-adhesive |
---|---|---|---|
A | 50 | Inside out | + |
B | 50 | Outside in | - |
C | 50 | Inside out | - |
D | 50 | Inside out | + |
Factors considered in evaluating relapse rate after PELD
Factors | Sub-Factors | Related 1 | Related 2 |
---|---|---|---|
Life Factors | Age | ||
Gender | |||
Disc Factors | Disc Degeneration Scale | DeCandido- scale 1-3 | |
Combined HNP | 0 level to 3 levels | ||
Disc Herniation Event | First | ||
Second | |||
Operation Factors | Anti-Adhesive Agent | + / - | |
Disc Location | Central, Paracentral, Foraminal | ||
Annulus Preservation along the Disc Protrusion | |||
Approach | Inside-Out | Group A, C, D | |
Outside-In | Group B | ||
Segmental Stability Factors | Herniated Disc Level | ||
Disc Height: Middle of Discal Space | |||
Segmental Dynamic Motion | Discrepancy of Flexion/Extension |
Preoperative and postoperative VAS score
Group | Follow-up (months) | Mean Age (years) | Recurrence (9.5%-19/200) | VAS Pre-op | VAS Final follow up |
---|---|---|---|---|---|
Group A | 21.12±4.57 | 47.78±17.38 | 12% (6/50) | 8.06±0.74 | 1.44±0.54 |
Group B | 12.54±3.41 | 45.52±14.40 | 4% (2/50) | 8.34±0.63 | 1.34±0.59 |
Group C | 19.00±4.42 | 46.38±16.89 | 6% (3/50) | 8.14±0.57 | 1.86±0.86 |
Group D | 19.82±2.73 | 47.16±15.64 | 16% (8/50) | 8.10±0.65 | 1.84±0.68 |
Relation of age with recurrence
Group (Yrs) | Patients (n) | Recurrence | % | p-value |
---|---|---|---|---|
<40 | 79 | 3 | 3.79 | 0.003 |
41-60 | 78 | 14 | 17.9 | |
>60 | 43 | 2 | 4.6 | |
Total | 200 | 19 | 9.5 |
The relation between degree of degeneration and recurrence
Group | Patients (n) | Recurrence | % | p-value |
---|---|---|---|---|
Scale 1 | 32 | 0 | 0 | 0.003 |
Scale 2 | 90 | 7 | 7.7 | |
Scale 3 | 78 | 12 | 15.3 | |
Total | 200 | 19 | 9.5 |
Relation of adjacent level HNP with recurrence
Group | Patients (n) | Recurrence | % | p-value |
---|---|---|---|---|
0 level | 85 | 3 | 3.5 | 0.001 |
1 level | 82 | 9 | 10.9 | |
2 level | 25 | 5 | 20 | |
3 level | 8 | 2 | 25 | |
Total | 200 | 19 | 9.5 |
Summary of the factors studied and its relation to recurrence
FACTORS | SUB-FACTORS | RELATION | Recurrence |
||
---|---|---|---|---|---|
Level | Total | % | |||
Life Factor | Age | + | ~40 years: | 3/79 | 3.79% |
41~60 years | 14/78 | 17.9% | |||
61 years~ | 2/43 | 4.6% | |||
Sex | - | ||||
Disc Factor | Degeneration Scale | + | Scale 1 | 0/32 | 0% |
Scale 2 | 7/90 | 7.7% | |||
Scale 3 | 12/78 | 15.3% | |||
Combined HNP | + | 0 Level | 3/85 | 3.5% | |
1 Level | 9/82 | 10.9% | |||
2 Level | 5/25 | 20% | |||
3 Level | 2/8 | 25% | |||
Disc type (1st/recurrence) | - | ||||
Operation Factor | Anti-adhesive agent | + | Use | 14/100 | 14% |
No Use | 5/100 | 5% | |||
Disc location | + | Central | 1/18 | 5.56% | |
Foraminal/Far Lateral | 2/44 | 4.5% | |||
Inferior/Superior/Paracentral | 16/138 | 11.59% | |||
Annulus Preservation | - | ||||
Approach | - | ||||
Segmental Stability Factor | Disc level | + | L1-2/L2-3/L3-4 | 2/51 | 3.92% |
L4-5 | 17/149 | 11.41% | |||
Disc height | + | ~80% | 4/23 | 17.4% | |
81~100% | 8/98 | 8.2% | |||
101%~ | 7/79 | 8.8% | |||
Dynamic motion | - |