DOI: https://doi.org/10.21203/rs.3.rs-1564205/v1
Background: Transforaminal Endoscopic Lmbar Discectomy (TELD) is widely applied for lumbar degenerative disease(LDD) and satisfactory short-term outcomes have been achieved. However, the mid-term and long-term follow-up of this technique is still lacking.
Objective: To retrospectively analyze the mid-term clinical efficacy of TELD for single-level LDD with a minimum of 6-year follow-up.
Methods: 75 patients with single-level LDD (lumbar disc herniation, lumbar spinal stenosis) who underwent TELD in our department from December 2014 to December 2015 were observed.Visual analog scale (VAS), Japanese Orthopaedic Association evaluation treatment (JOA) score and Oswestry Disability Index (ODI) were calculated and compared before operation, 3 months after operation, 6 months after operation, 1 year after operation and at the last follow-up. Disc Height (DH), disc range of motion (ROM) and disc degeneration on standard lumbar lateral radiographs before operation and at the last follow-up were determined. Recurrence rate and operation-related complications during follow-up were recorded.
Results: 64 cases were included and followed up for 6.4±0.1 years. There were no complications such as infection, epidural hematoma and nerve root injury. There were significant differences in VAS, JOA, ODI between preoperative and postoperative 3 months, 6 months, 1 year and last follow-up (P < 0 01), VAS, JOA, ODI at 3 months after operation were different from 6 months after operation (P < 0 05), and there were significant differences compared with preoperative, 1 year after operation and last follow up (P < 0 01). VAS, JOA and ODI at 6 months after operation were significantly different from those before operation (P < 0.01), but not significantly different from those at 1 year after operation and the last follow-up (P > 0.05). There was no significant difference in DH,ROM and the Pfirrmann grade of intervertebral disc preoperative and the last follow-up. During the follow-up period, 3 patients (4.69%) were recurrent, 1 patient (1.67%) found dural rupture and cauda equina hernia, 13 patients (20.31%) had various degrees of POD, and 3 patients (4.69%) had various degrees of muscle weakness.
Conclusion: TELD has a satisfactory mid-term efficacy, and has no significant effect on the DH, the stability of the intervertebral disc space, or on intervertebral disc degeneration. However, as expected, TELD was associated with some complications including recurrent disc herniation and POD.
With the development of minimally invasive technology, percutaneous endoscopic surgery has gradually become an important surgical approach for lumbar degenerative diseases (LDDs), with the transforaminal approach being the most widely utilized minimally invasive approach for lumbar discectomy[1,2]. At present, there are many studies on the treatment of LDD by transforaminal endoscopic lumbar discectomy (TELD), but most of these studies evaluated preoperative indications and assessed short-term follow-up without evaluating mid- and long-term outcomes. We retrospectively analyzed 64 patients with LDD treated with TELD in our hospital from December 2014 to December 2015 with a follow-up of at least 6 years. The relevant data were sorted and analyzed as follows:
1.1 General data
From December 2014 to December 2015, 75 patients with single segmental LDD (lumbar disc herniation, lumbar spinal stenosis) who underwent TELD in our hospital were selected as the study subjects; 11 cases fell off, 2 cases refused a hospital visit, 7 cases lost contact, 2 cases died of medical diseases, and 64 cases were followed for at least 6 years, including 28 males and 36 females, with an average age of 57.72 ± 18.31 years. There were 49 cases of lumbar disc herniation (LDH), 15 cases of lumbar spinal stenosis (LSS), 3 cases in L2/3, 8 cases in L3/4, 34 cases in L4/5 and 19 cases in L5/S1. The follow-up ranged from 6.1 to 6.6 years with an average of 6.4 ± 0.1 years.
1.2 Inclusion Criteria:
(1) A diagnosis of LDH or LSS based on the patient's medical history, signs and imaging, with the involved segment clearly defined as a single segment;
(2) Unsatisfactory results after systematic conservative treatment for more than 3 months;
(3) No previous lumbar surgery history;
(4) No obvious surgical contraindications;
(4) Patients and their families had good compliance and were willing to cooperate with treatment and follow visits;
(5) Follow-up data was complete.
1.3 Exclusion Criteria
(1) Previous lumbar surgery;
(2) Patients with spondylolysis, severe lumbar instability, lumbar spondylolisthesis, and tumors in the lumbar spinal canal;
(3) Multisegmental lesions- the involved segment could not be defined as a single segment;
(4) L5/S1 disc herniation in patients where a superiorly located iliac crest made the transforaminal approach impossible;
(5) Patients or their families had poor compliance and were unwilling to cooperate with treatment and follow up visits;
(6) Patients with a history of psychological disorders;
(7) Follow-up data was incomplete.
1.4 Surgical methods
The operation was performed by senior doctors in the same group. The TESSYS endoscopic spinal surgery system (endoscope, 18G puncture needle, soft tissue dilatation tube, working channel, nucleus pulposus forceps and blue forceps, etc.) produced by Joimax Company in Germany, and an Elliquence disposable radiofrequency plasma operation electrode were used. All patients underwent a transforaminal approach in the prone position under local anesthesia. After conventional catheterization, the operation was conducted utilizing the endoscope. Care was taken to avoid injury to the dura mater, nerve roots, and intervertebral endplates. The ligaments and small joints were preserved as much as possible, and 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 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 the operation depending on the amount of drainage.
1.5 Observation Index
(1) Visual Analog Score (VAS), Japanese Orthopedic Association Score (JOA), and Oswestry Disability Index (ODI): preoperation, 3 months, 6 months, 1 year after operation and the last follow-up.
(2) Imaging indices: disc height (DH), range of motion (ROM) (Fig. 1) and the degree of intervertebral disc degeneration [3] (Table 1) were measured on standard lumbar lateral radiographs before the operation and at the last follow-up. ROM > 10° was defined as lumbar instability.
|
Grade |
Structure |
Signal Intensity |
Distinction of Nucleus and Anulus |
Disc Height |
|---|---|---|---|---|
|
I |
Homogeneous, bright white |
Hyperintense, isointense to cerebrospinal fluid |
Clear |
Normal |
|
II |
Inhomogeneous with or without horizontal bands |
Hyperintense, isointense to cerebrospinal fluid |
Clear |
Normal |
|
III |
Inhomogeneous, gray |
Intermediate |
Unclear |
Normal to slightly decreased |
|
IV |
Inhomogeneous, gray to black |
Intermediate to hypointense |
Lost |
Normal to moderately decreased |
|
V |
Inhomogeneous, black |
Hypointense |
Lost |
Collapsed disc space |
(3) Recurrence rate: the proportion of patients with ipsilateral recurrence of the same segment during the follow-up period.
(4) Operation-related complications: nerve injury, infection, dural rupture, postoperative dysesthesia (POD), etc.
1.6 Statistical Analysis
Measurement data are expressed as the mean ± standard deviation. All data were analyzed via SPSS 23.0 software. Count data were compared with the chi-squared test. The independent sample F test was used for intergroup comparisons. P < 0.05 was considered statistically significant, and P < 0.01 was deemed highly significant.
2.1 VAS, JOA, ODI
There were significant differences in VAS, JOA, and ODI preoperative and postoperative values at 3 months, 6 months, 1 year and last follow-up (P < 0 01). The VAS, JOA, and ODI scores 3 months after the operation were significantly different from those 6 months after the operation (P < 0 05), and there were significant differences compared with values preoperatively and at the 1-year and last follow-ups (P < 0 01). The VAS, JOA and ODI at 6 months after the operation were significantly different from those before the operation (P < 0.01) but not significantly different from those at 1 year and the last follow-up (P > 0.05). See Table 2 for details.
|
Preoperative |
Postoperative 3 months |
Postoperative 6 months |
Postoperative 1 years |
Last follow-up |
F |
P |
|
|---|---|---|---|---|---|---|---|
|
VAS |
8.64 ± 0.97 |
2.13 ± 1.28 |
1.69 ± 1.24 |
1.55 ± 1.08 |
1.45 ± 1.08 |
490.68 |
0 |
|
JOA |
7.56 ± 4.25 |
22.22 ± 3.84 |
23.63 ± 3.83 |
24.11 ± 3.51 |
24.58 ± 2.91 |
245.84 |
0 |
|
ODI |
71.86 ± 12.98 |
14.03 ± 6.12 |
11.48 ± 4.67 |
10.59 ± 3.75 |
10.03 ± 3.37 |
923.273 |
0 |
2.2 Imaging indices
DH was 10.22 ± 0.65 mm before the operation and 10.19 ± 0.66 mm at the last follow-up, but there was no significant difference between them (P > 0.05). The ROM was 5.59 ± 2.22° before the operation and 5.41 ± 2.31° at the last follow-up, but there was no significant difference between them (P > 0.05). See Table 3 for details.
|
Preoperative |
Last follow-up |
t |
P |
|
|---|---|---|---|---|
|
DH(mm) |
10.22 ± 0.65 |
10.19 ± 0.66 |
0.211 |
0.833 |
|
ROM(°) |
5.59 ± 2.22 |
5.41 ± 2.31 |
0.469 |
0.640 |
Before the operation, there were 10 patients with Pfirrmann grade III, 21 patients with IV, and 33 patients with V. At the last follow-up, there were 3 patients with Pfirrmann grade III, 19 patients with IV, and 42 patients with V. There was no significant difference between them (P > 0.05). See Table 4 for details.
|
I |
II |
III |
IV |
V |
|
|---|---|---|---|---|---|
|
Preoperative |
0 |
0 |
10 |
21 |
33 |
|
Last follow-up |
0 |
0 |
3 |
19 |
42 |
|
X2 |
4.949 |
||||
|
P |
0.084 |
||||
2.3 Recurrence Rate
During the follow-up period, 3 patients (4.69%) had lower limb root pain caused by ipsilateral intervertebral disc herniation, 1 case appeared after bending down to carry heavy objects approximately 1 month after operation, 2 cases returned to normal work (sedentary station for a long time), 1 case underwent endoscopic surgery again, 1 case underwent Mis-TLIF operation, and there were no symptoms in the last follow-up.
2.4 Operation-related Complications
No patients experienced postoperative infection, epidural hematoma, or nerve root injury. 1 patient (1.67%) was found to have dural rupture and cauda equina hernia during the operation. No obvious CEREBROspinal fluid leakage was observed after drainage tube placement, and no obvious symptoms related to cerebrospinal fluid leakage were found in the patient.Up to the last follow-up, there were no obvious symptoms. Thirteen patients (20.31%) showed various degrees of POD, all of whom recovered within 3 months after the operation, and 3 patients (4.69%) showed various degrees of muscle weakness and completely returned to normal within 6 months after physiotherapy, such as nourishing nerves and acupuncture.
TELD is increasingly widely used in the treatment of lumbar degenerative diseases because of its advantages of less trauma, less bleeding and rapid recovery[1, 4]. At present, there are many reports about the short-term efficacy of TELD[1,2,5−7], but there are few reports on the medium- and long-term clinical evaluation of TELD for more than 5 years.
Sang et al.[8] followed 62 patients after TELD for 10 years and found that 9.6% of the patients underwent open revision surgery at the same segment, and 26.6% of the patients underwent other lumbar surgery. The DH was well maintained. They considered that long-term results of TELD were favorable. Multiple experts [9–11] conducted studies for at least 5 years and found that TELD could achieve satisfactory long-term clinical results. Li et al.[4] followed 42 TELD patients for at least 7 years; 6 patients (14.29%) showed POD, only 2 patients (4.76%) showed mild sensory impairment during the last follow-up, 2 patients (4.76%) underwent revision surgery during the last follow-up period, and no instability of surgical segments was found during the last follow-up. They concluded that TELD can achieve good results after long-term follow-up, that postoperative sensory impairment was a common early complication and that limited intraoperative disc removal could well protect DH and minimize the risk of residual back pain. In our study, the VAS, JOA and ODI scores of all patients at 3 months, 6 months, and 1 year after the operation and at the last follow-up were significantly alleviated compared with those before the operation. VAS, JOA and ODI at 6 months after operation were significantly different from 3 months after operation; VAS, JOA and ODI at 6 months after operation were not significantly different from 1 year after operation and the last follow-up. We believe that postoperative recovery from TELD may have basically stabilized at 6 months after the operation.
At present, the clinical evaluation of lumbar intervertebral disc degeneration mainly uses imaging evaluation methods, and the most commonly used is Pfirrmann grade, which is divided into 5 grades according to structure, signal intensity, distinction of nucleus and anulus, and disc height[3]. Sang et al.[8] reported that DH 10 years after TELD was 81.54 ± 17.40% of that before TELD, and there was no significant difference between the two. Li et al.[4] reported that DH 7 years after TELD was 84.52 ± 5.66% of that before TELD, with no significant difference between the two. Our study found no significant difference in DH between the patients at the last follow-up and before the operation, which was consistent with the results of the above scholars. Meanwhile, we found no significant difference in the Pfirrmann grade between the patients at the last follow-up and before the operation, suggesting that TELD may have no significant effect on accelerating intervertebral disc degeneration. This has not been reported in the literature thus far.
The effect of the operation on the stability of the operative segment is also an important index for the evaluation of postoperative efficacy. Sang et al.[8] reported that no obvious lumbar instability was found 10 years after TELD, and Li et al.[4] reported that no obvious lumbar instability was found 7 years after TELD. Our study found that there was no significant difference in ROM between the last follow-up patients and those before TELD, and no obvious lumbar instability was found.
Postoperative recurrence is an inevitable problem in the simple removal of the nucleus pulposus and has also become an important reference index restricting the extensive application of this operation. Sang et al.8] reported that the 10-year postoperative recurrence rate of TELD was approximately 9.6% (6/62). Li et al.[4] reported that the postoperative recurrence rate of TELD was approximately 4.76% (2/42) 7 years after TELD. Thomas et al. [12] reported that the TELD recurrence rate was approximately 4.76% (4/84). Anthony Yeung et al. [13] conducted at least a 5-year follow-up and found that the recurrence rate of the YESS technique was 5.1% (9/176) and that of the TESSYS technique was 10% (9/90). In our 6-year follow-up, the postoperative recurrence rate was approximately 4.68% (3/62), all of which occurred within 3 months after the operation; these findings are consistent with what Li et al. [4] and Thomas et al. [12] reported.
Postoperative complications are also a common concern of clinicians and patients. TELD complications are relatively rare, and include infection, epidural hematoma, nerve root injury, dural tear, POD, exit root stimulation and other complications [1, 4, 9]. The incidence of POD is relatively high, generally more than 10%[13]. In our study, 13 patients (20.97%) showed various degrees of POD, which recovered spontaneously within 3 months after the operation with oral Mecobalamin tablets and Fufang Wulingzhi Tangjiang. Three patients (4.84%) showed various degrees of muscle weakness, which recovered completely within 6 months after physiotherapy, including nourishing nerves and acupuncture. The possible reasons for POD were (1) insufficient foraminoplasty, narrow operating space, and stimulation of exit root and walking root by working channel; (2) severe nerve compression before operation and reactive nerve root edema after decompression; (3) excessive use of radiofrequency around nerve root during operation; (4) blood clot stimulation in the postoperative operation area.
We believe that TELD has a satisfactory medium- and long-term effect and has no significant effect on DH, ROM or intervertebral disc degeneration, but it also inevitably has some complications, such as recurrence and POD. The consequences of these complications are generally not permanent and intraoperative operations can be refined to reduce their incidence. However, due to certain limitations of this study, such as single-center retrospective studies and selection bias, the results of this study may be biased and need to be further confirmed by multicenter randomized controlled studies and longer follow-up times.
Ethical approval
This research was approved by Hubei 672 Orthopaedics Hospital of Integrated Chinese & Western Medicine Ethics Committee(Wuhan, China; permit no. HB6720298) and was in conformity with the guidelines of the National Institute of Health.
Consent for Participation
Written informed consents were formally obtained from all participants.
Acknowledgements
Not applicable.
Funding
No funding was received.
Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Authors' contributions
JT,QLL and YL made substantial contributions to the study conception and design, the acquisition of data and the analysis and interpretation of data. CJW,WX, XGL and XWG contributed to drafting the manuscript and critically revising the manuscript for important intellectual content. JT and QLL prepared the manuscript. All authors read and approved the final manuscript.
Competing interests
The authors declare that they have no competing interests.