Abstract
Objective
To compare the clinical efficacy of percutaneous transforaminal endoscopy-assisted lumbar interbody fusion (PT-Endo-LIF) and posterior lumbar interbody fusion (PLIF) for degenerative lumbar spinal stenosis (DLSS).
Results
The observation group had lower Visual Analogue Scale(VAS) scores at postoperative 7 days, 1 month and 3 months. At 1 month postoperatively, its Oswestry Disability Index(ODI) and (Japanese Orthopaedic Association)JOA improvements were significantly superior (p < 0.05); at 3 months, all score improvements were comparable between groups[VAS, ODI, JOA, Short-Form 36 Health Survey (SF-36)]. The observation group had longer operation time, but significantly less blood loss, shorter ambulation time and fewer complications.PT-Endo-LIF yields favorable short-term efficacy for DLSS, with 3-month efficacy similar to PLIF and fewer complications, facilitating faster postoperative recovery.
Keywords: Microscopic fusion, Degenerative lumbar spinal stenosis, Efficacy analysis
Introduction
Briggs and Milligan [1] pioneered posterior lumbar interbody fusion (PLIF) in 1944, establishing a foundation for the subsequent development of various lumbar fusion techniques. Contemporary lumbar fusion procedures are primarily classified into anterior and posterior approaches. Anterior techniques include anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), and oblique lateral lumbar interbody fusion (OLIF). In contrast, posterior approaches mainly consist of PLIF, transforaminal lumbar interbody fusion (TLIF), and minimally invasive TLIF (MIS-TLIF) [2]. Each surgical method possesses specific indications, advantages, and limitations, with the overarching objective of enhancing lumbar fusion through increased minimal invasiveness, reduced complications, and expedited postoperative recovery.
In the past two decades, the adoption of minimally invasive lumbar surgery has increased significantly across various lumbar procedures due to its considerable advantages [3–4]. Statistics indicate that minimally invasive lumbar surgery comprised one-sixth of all spinal surgeries in the United States in 2010, with this proportion rising to one-third by 2016.
With the evolution of percutaneous endoscopic lumbar discectomy (PELD), PT-Endo-LIF has emerged as an effective treatment for lumbar degenerative disease, showing enhanced efficacy [5–10]. A meta-analysis indicated that PT-Endo-LIF, MIS-TLIF, and OTLIF are comparable in terms of operative time, complication rate, fusion rate, leg pain VAS score, and JOA score [11]. Moreover, Relvas-Silva et al. [12] further confirmed PT-Endo-LIF as a safe and effective alternative to traditional lumbar interbody fusion.
Comparisons of clinical efficacy between PT-Endo-LIF and PLIF are limited. To address this gap, a comparative analysis of the two techniques was conducted on 44 DLSS patients treated at Sanshui District People’s Hospital of Foshan between May 2021 and May 2024. The findings are presented in this report.
Literature and methods
General information
A total of 44 patients with degenerative lumbar spinal stenosis (DLSS) who underwent either posterior transforaminal endoscopic lumbar interbody fusion (PT-Endo-LIF) or posterior lumbar interbody fusion (PLIF) at the Sanshui District People’s Hospital of Foshan City from May 2021 to May 2024 were selected for this study. The patients were divided into an observation group and a control group, with 22 patients in each group. All participants provided written informed consent prior to surgery. Relevant demographic data, clinical symptoms, and radiological outcomes were collected for analysis.
Inclusion and exclusion criteria
The inclusion criteria were as follows: ① radiographic evidence of lumbar spinal stenosis and/or foraminal stenosis, with or without disc herniation; ② definitive radicular symptoms (such as radiating pain, numbness, and weakness) that align with imaging findings; ③ failure of conservative treatment, which must include physical therapy and selective nerve root block for a minimum of 6 weeks; ④ capacity to comprehend pain rating scales; provision of informed consent and voluntary participation in this study; and completion of a signed informed consent form.
The exclusion criteria included the following: ① congenital spinal stenosis; a prior history of lumbar surgery, fracture, tumor, infection, or other medical conditions; pregnant women; and individuals with mental disorders; ② patients with significant underlying diseases; ③ individuals with a history of chronic pain or opioid misuse; and ④ patients deemed unsuitable for participation by the investigator.
Methods
Patients fasted for 8 h and refrained from oral water intake for 4 h before surgery. All procedures were performed by a sole surgeon under general anesthesia assisted by endotracheal intubation.
Patients in the observation group underwent PT-Endo-LIF utilizing a German SPINENDOS lumbar spinal endoscope (working length: 95 mm; outer diameter: 7 mm; inner diameter: 4.3 mm). The surgical protocol was as follows: After successful induction of general anesthesia, the patient was positioned prone with abdominal suspension, and both upper limbs were placed in a comfortable lateral cephalad position. Fluoroscopic localization of the target pedicle shadow was conducted, followed by skin marking and routine sterile preparation. Needle puncture was performed with orthotopic positioning at the lateral pedicular margin of the affected side of the target intervertebral space, along with lateral positioning at the inferior foraminal edge. Subsequently, a guidewire was inserted, the puncture needle was withdrawn, and a transverse skin incision was made along the guidewire. The working channel was then introduced and positioned along the guidewire. Under endoscopic visualization, a trephine was utilized to resect the superior portion of the articular process, thereby enlarging the neural foramen to facilitate access to the spinal canal. Following this, the endoscope was introduced through the working channel for endoscopic spinal decompression. Portions of the ligamentum flavum, posterior longitudinal ligament, and intervertebral disc nucleus pulposus were resected to achieve sufficient decompression of the dural sac and nerve roots.The nucleus pulposus and partial endplate were excised to expose the intervertebral disc space. Endoscopic inspection confirmed that the bony endplate region designated for bone grafting was intact and sufficiently sized. A trial cage was utilized to ascertain the optimal dimensions.A mixture of autologous and allogeneic bone was subsequently injected into the intervertebral space, followed by the implantation of a properly sized intervertebral fusion device pre-filled with bone graft material. Fluoroscopy was utilized to confirm the correct positioning of the cage. Intraspinal exploration was then performed to evaluate the nerve roots and dural sac, along with comprehensive debridement to ensure complete decompression, the absence of significant neural compression, and normal pulsation of the dural sac. Following this, the endoscope and working sleeve were removed, and percutaneous pedicle screws were inserted for internal fixation, thereby completing the procedure (Fig. 1).
Fig. 1.
A 71-year-old female patient with L4-5 (with lumbar 4 vertebral anterior I° spondylolisthesis) DLSS in the PT-Endo-LIF group. A–C Preoperative x-ray, CT, and MRI indicated the L4-5 spinal stenosis combined with anterior I° spondylolisthesis of the L4 vertebra and L4‒5 disc bulging with ligamentum flavum hypertrophy. D Puncture needle puncture, the orthotopic position at the lateral edge of the pedicle on the affected side of the target intervertebral space, and the lateral position at the inferior edge of the foramen. The guidewire was inserted, and the puncture needle was removed. E Place the working channel along the wire. F The bone of the upper ventral part of the upper articular process was removed with a trephine, and the intervertebral foramen was enlarged. G L4‒5 spinal canal decompression was performed via endoscopy, and the nerve root was released. H The endplate after endoscopic treatment. I The appropriately sized cage was placed. J–L Postoperative review of the x-ray, CT, and MRI indicated that L4-5 spinal stenosis had improved and that the lumbar 4 spondylolisthesis had reset. M Patient wounds after surgery
Patients in the control group underwent posterior lumbar interbody fusion (PLIF) using the following procedure: Following successful induction of general anesthesia, patients were positioned prone with abdominal suspension, and both upper limbs were placed in a comfortable lateral cephalad posture. Routine sterile preparation was conducted, after which a midline transverse incision was made at the level of the target intervertebral space. The subcutaneous fascia was incised layer by layer, and the paraspinal muscles were dissected from the laminae to expose the laminae and articular processes. Positioning needles were inserted at the lambdoid processes of the bilateral superior and inferior articular processes of the target segment, and C-arm fluoroscopic confirmation was obtained prior to tapping and inserting the appropriate pedicle screws. Posterior decompression was achieved through the resection of the laminae and ligamentum flavum, thereby exposing the dural sac and nerve roots. The nerve roots were carefully retracted and protected while accessing the intervertebral space. Nucleus pulposus tissue was excised, and the vertebral endplates were meticulously prepared using a curette. The intervertebral space was distracted with titanium rods, thoroughly irrigated, and packed with a mixture of autologous and allogeneic bone grafts. A suitably sized interbody cage, pre-filled with bone graft material, was implanted and secured with compression fixation. Finally, intraoperative inspection was conducted to confirm adequate decompression of the nerve roots and dural sac, after which the procedure was concluded (Fig. 2).
Fig. 2.
A 52-year-old female patient with L4-5 (with lumbar 4 vertebral anterior I° spondylolisthesis) DLSS in the PLIF group. A–C Preoperative x-ray, CT, and MRI indicated the obvious L4‒5 spinal stenosis combined with anterior I° spondylolisthesis of the L4 vertebra and L4‒5 disc bulging. D The dural sac and nerve root were decompressed under direct visual guidance intraoperatively. E–F Postoperative review of the x-ray and CT images revealed that L4‒5 spinal stenosis improved and that the incidence of L4 spondylolisthesis decreased. G Picture of the patient’s wound after surgery
Routine postoperative interventions, including haemostasis, analgesia, detumescence, neurotrophic therapy, and thrombosis prophylaxis, were administered to both groups. Patients were instructed to wear a waist brace for 3 months following surgery, accompanied by early rehabilitation guidance tailored to their individual postoperative status.
Indicators of observation
Lumbar and lower extremity pain was evaluated using the Visual Analog Scale (VAS) preoperatively and at 7 days, 1 month, and 3 months postoperatively, with scores demonstrating a positive correlation with pain severity. The Oswestry Disability Index (ODI) and Japanese Orthopaedic Association (JOA) scores were assessed preoperatively and at 1 and 3 months postoperatively, while the Short Form-36 (SF-36) scores were analyzed at baseline and during the 3-month follow-up. Operative duration, intraoperative blood loss, and postoperative off bed time were recorded for all patients. Furthermore, perioperative complications were documented and subjected to statistical analysis for both groups.
Statistical methods
The data were analyzed utilizing SPSS 25.0 statistical software. Measurement data were presented as means ± standard deviations (mean ± SD). Normality and homogeneity of variance tests were performed using the Kolmogorov‒Smirnov and Levene tests. Independent sample t-tests and Mann‒Whitney U tests were employed for non-normally distributed data. Count data were described in frequencies and percentages (n,%). The Fisher’s exact probability test was applied, with statistical significance set at p < 0.05.
Results
Baseline characteristics
The observation group, consisting of 10 males and 12 females, included 21 single-segment cases and 1 double-segment case, with a mean age of 57.27 ± 14.733 years (range, 26–81 years). The control group, also comprising 10 males and 12 females, had 21 single-segment cases and 1 double-segment case, with a mean age of 59.05 ± 10.869 years (range, 42–77 years). The distribution of age and surgical segments was comparable between the two groups, with no significant differences observed (p > 0.05; Table 1).
Table 1.
Comparison of general data between the two groups (n=22)
| Observation group (PT-Endo-LIF) | Control group (PLIF) | p value | |
|---|---|---|---|
| Sex (n, male/female) | 10/12 | 10/12 | 1.0 |
Age 
|
57.27±14.73 | 59.05±10.87 | 0.652 |
| Surgical segment (n,%) | |||
| L3-4 | 1(4.55) | 4(18.18) | |
| L4-5 | 15(68.18) | 12(54.55) | |
| L5-S1 | 7(31.82) | 7(31.82) | |
| Total | 23 (100.00) | 23 (100.00) | 0.488 |
PT-Endo-LIF percutaneous transforaminal endoscopy-assisted lumbar interbody fusion, PLIF posterior lumbar interbody fusion
Comparison of the efficacy between the two patient groups
VAS scores demonstrated significant improvement at postoperative day 7, 1 month, and 3 months in both groups compared to preoperative levels (p < 0.05). Additionally, ODI and JOA scores exhibited marked enhancements at 1 and 3 months postoperatively (p < 0.05). The PT-Endo-LIF group reported significantly lower VAS scores at day 7 and 1 month, along with superior ODI and JOA scores at 1 month, compared to the PLIF group (p < 0.05). However, at 3 months postoperatively, no significant intergroup differences were observed in VAS, ODI, JOA, or SF-36 scores (p > 0.05), although both groups showed significant improvements in SF-36 scores from baseline (p < 0.05). (Tables 2 and 3)
Table 2.
Comparison of the VAS score, ODI, and JOA score between the two groups (mean ± SD, n=22)
| Observation group (PT-Endo-LIF) | Control group (PLIF) | p value | |
|---|---|---|---|
| VAS score | |||
| Preoperative | 6.14±1.21 | 6.82±0.85* | 0.0362 |
| Postoperative 7 days | 3.18±1.01# | 4.27±0.77#* | 0.0002 |
| Postoperative 1 month | 1.77±0.69# | 2.64±0.49#* | 0.0001 |
| Postoperative 3 months | 1.00±0.82# | 1.18±0.73# | 0.2270 |
| ODI | |||
| Preoperative | 23.82±6.79 | 27.73±2.41* | 0.0005 |
| Postoperative 1 month | 11.55±2.35# | 15.82±2.61#* | <0.0001 |
| Postoperative 3 months | 9.32±2.23# | 9.5±1.60# | 0.7905 |
| JOA score | |||
| Preoperative | 10.14±3.45 | 8.09±1.38* | 0.0483 |
| Postoperative 1 month | 12.36±0.95# | 10.64±0.95#* | <0.0001 |
| Postoperative 3 months | 13.41±0.80# | 13.23±0.92# | 0.6010 |
PT-Endo-LIF percutaneous transforaminal endoscopy-assisted lumbar interbody fusion, PLIF posterior lumbar interbody fusion, VAS visual analogue scale, ODI Oswestry Disability Index, JOA Japanese Orthopaedic Association
(#): Compared with the preoperative group, p <0.05; (*): Compared with the observation group, p <0.05.The above data have undergone Bonferroni correction
Table 3.
Comparison of SF-36 scores between the two patient groups (mean ± SD, n=22)
| Observation group (PT-Endo-LIF) | Control group (PLIF) | p value | |
|---|---|---|---|
| Physical functioning (PF) | |||
| Preoperative | 43.45±5.42 | 39.55±5.48* | 0.0221 |
| Postoperative 3 months | 71.91±4.39# | 71.82±7.12# | 0.964 |
| Role physical (RP) | |||
| Preoperative | 35.91±5.70 | 30.91±4.26* | 0.002 |
| Postoperative 3 months | 75.68±7.61# | 71.59±7.14# | 0.1115 |
| Bodily pain (BP) | |||
| Preoperative | 37.27±8.27 | 31.82±8.53* | 0.0348 |
| Postoperative 3 months | 82.73±12.03# | 80.45±10.90# | 0.1842 |
| General health (GH) | |||
| Preoperative | 38.82±5.11 | 34.91±5.55* | 0.0194 |
| Postoperative 3 months | 77.09±7.00# | 75.45±6.57# | 0.3905 |
| Vitality (VT) | |||
| Preoperative | 39.09±5.49 | 32.05±5.49* | 0.0003 |
| Postoperative 3 months | 79.32±6.78# | 78.86±6.89# | 0.8318 |
| Social functioning (SF) | |||
| Preoperative | 54.55±6.71 | 47.27±7.03* | 0.001 |
| Postoperative 3 months | 80.00±6.90# | 81.82±7.95# | 0.1468 |
| Role – emotional (RE) | |||
| Preoperative | 78.18±7.22 | 84.18±6.48* | 0.0111 |
| Postoperative 3 months | 95.18±6.48# | 97.27±5.66# | 0.3274 |
| Mental health (MH) | |||
| Preoperative | 61.82±19.43 | 58.18±5.89 | 0.135 |
| Postoperative 3 months | 98.18±5.89# | 98.18±5.89# | 0.2306 |
PT-Endo-LIF percutaneous transforaminal endoscopy-assisted lumbar interbody fusion, PLIF posterior lumbar interbody fusion
(#) Compared with the preoperative data, p <0.05; (*): Compared with the control group, p <0.05
Comparison of the perioperative characteristics between the two groups
Intraoperative blood loss and postoperative ambulation time were significantly lower in the PT-Endo-LIF group compared to the PLIF group (p < 0.05). However, PT-Endo-LIF was associated with a longer operative duration (p < 0.05; Table 4).
Table 4.
Comparison of the perioperative characteristics of the two groups [mean ± SD, n=22]
| Project | Observation group (PT-Endo-LIF) | Control group (PLIF) | p value |
|---|---|---|---|
| Time of surgery (min) | 292.82±85.69 | 242.95±45.35 | 0.020 |
| Intraoperative blood loss volume (ml) | 169.09±136.52 | 359.09±138.36 | <0.001 |
| Postoperative off bed time (days) | 5.32±1.39 | 7.64±2.61 | 0.001 |
PT-Endo-LIF percutaneous transforaminal endoscopy-assisted lumbar interbody fusion, PLIF posterior lumbar interbody fusion
Comparison of the rates of postoperative procedure-related complications between the two groups
One patient in the PT-Endo-LIF group developed a postoperative urinary tract infection, which presented with frequency, urgency, and positive urinary leukocytes; this condition resolved following anti-infective treatment. In the PLIF group, two patients experienced similar urinary tract infections, and one patient developed an infection at the surgical incision site. The latter was managed through debridement, one week of continuous saline irrigation, and anti-infective therapy, resulting in resolution for all cases. Neither group experienced dural sac injury, cerebrospinal fluid leakage, or nerve root injury. The surgery-related complication rates were 0% for PT-Endo-LIF compared to 4.55% for PLIF, while the perioperative complication rates were 4.55% versus 13.63%. These differences were not statistically significant (p > 0.05; Table 5). However, from a quantitative perspective, the PT-Endo-LIF group exhibited fewer complications.
Table 5.
Comparison of the rates of postoperative procedure-related complications between the two groups (n=22,%)
| Observation group (PT-Endo-LIF) | Control group (PLIF) | p value | |
|---|---|---|---|
| Surgery-related complication | 0(0.00) | 1(4.55) | 1.000 |
| Perioperative complication | 1(4.55) | 3(13.63) | 0.612 |
PT-Endo-LIF percutaneous transforaminal endoscopy-assisted lumbar interbody fusion, PLIF posterior lumbar interbody fusion
(Surgery-related complications refer to adverse events directly attributable to surgical manipulation, including wound infection, intraoperative vascular/nerve injury, improper implant placement, surgical site bleeding, and dural tear.
Perioperative complications include all adverse events occurring within 30 days after surgery, encompassing surgery-related complications, postoperative medical complications (e.g., urinary tract infection, pulmonary infection), and perioperative management-related events (e.g., wound infection, electrolyte disturbance).
The results of the normality test for the two data groups are presented in Table 6.
Table 6.
Result of normality test (Kolmogorov‒Smirnov test)
| Basic efficacy indicators | Observation group (PT-Endo-LIF) | Control group (PLIF) | |||
|---|---|---|---|---|---|
| D-value (p-value) |
Normality | D-value (p-value) |
Normality | ||
| VAS score | Preoperation | 0.273 (0.061) | Yes | 0.221 (0.201) | Yes |
| Postoperation Day 7 | 0.254 (0.099) | Yes | 0.283 (0.047) | No | |
| Postoperation Month 1 | 0.266 (0.072) | Yes | 0.406 (0.001) | No | |
| Postoperation Month 3 | 0.273 (0.062) | Yes | 0.234 (0.152) | Yes | |
| ODI score | Preoperation | 0.249 (0.109) | Yes | 0.208 (0.259) | Yes |
| Postoperation Month 1 | 0.154 (0.618) | Yes | 0.123 (0.854) | Yes | |
| Postoperation Month 3 | 0.177 (0.445) | Yes | 0.305 (0.026) | No | |
| JOA score | Preoperation | 0.141 (0.723) | Yes | 0.208 (0.258) | Yes |
| Postoperation Month 1 | 0.215 (0.226) | Yes | 0.215 (0.226) | Yes | |
| Postoperation Month 3 | 0.287 (0.042) | No | 0.254 (0.099) | Yes | |
| SF-36 subscales | |||||
| Physical functioning (PF) | Preoperation | 0.122 (0.863) | Yes | 0.215 (0.227) | Yes |
| Postoperation Month 3 | 0.174 (0.470) | Yes | 0.176 (0.451) | Yes | |
| Role-Physical (RP) | Preoperation | 0.245 (0.119) | Yes | 0.221 (0.201) | Yes |
| Postoperation Month 3 | 0.218 (0.215) | Yes | 0.184 (0.400) | Yes | |
| Bodily pain (BP) | Preoperation | 0.311 (0.022) | No | 0.221 (0.201) | Yes |
| Postoperation Month 3 | 0.317 (0.018) | No | 0.289 (0.040) | No | |
| General health (GH) | Preoperation | 0.163 (0.551) | Yes | 0.260 (0.085) | Yes |
| Postoperation Month 3 | 0.153 (0.629) | Yes | 0.246 (0.117) | Yes | |
| Vitality (VT) | Preoperation | 0.227 (0.178) | Yes | 0.387 (0.002) | No |
| Postoperation Month 3 | 0.233 (0.157) | Yes | 0.213 (0.237) | Yes | |
| Social functioning (SF) | Preoperation | 0.337 (0.010) | No | 0.424 (0.000) | No |
| Postoperation Month 3 | 0.273 (0.062) | Yes | 0.272 (0.062) | Yes | |
| Role-emotional (RE) | Preoperation | 0.190 (0.357) | Yes | 0.205 (0.273) | Yes |
| Postoperation Month 3 | 0.362 (0.004) | No | 0.458 (0.000) | No | |
| Mental health (MH) | Preoperation | 0.235 (0.148) | Yes | 0.530 (0.000) | No |
| Postoperation Month 3 | 0.496 (0.000) | No | 0.530 (0.000) | No | |
PT-Endo-LIF percutaneous transforaminal endoscopy-assisted lumbar interbody fusion, PLIF posterior lumbar interbody fusion
Discussion
Lumbar degenerative diseases are common orthopedic disorders that significantly diminish the quality of life for middle-aged and elderly individuals. The indications for endoscopic interventions in spinal disorders are broadening to include spinal instability, refractory pain, and adjacent segment degeneration. Clinical studies comparing PT-Endo-LIF and MIS-TLIF have shown that these two techniques have similar indications for managing lumbar diseases and produce favorable clinical outcomes [13–14]. Notably, PT-Endo-LIF results in a more substantial improvement in postoperative VAS low back pain scores during the immediate postoperative period.
Lumbar fusion is considered the gold standard surgical intervention for conditions such as lumbar spinal stenosis, lumbar disc herniation, and lumbar spondylolisthesis. The posterior lumbar interbody fusion performed via the interlaminar approach requires extensive dissection of the paravertebral muscles, resection of the posterior ligament complex, and intraoperative exposure and manipulation of the intervertebral space. These maneuvers place significant traction on the dural sac and nerve roots, which may lead to nerve injury and epidural scar adhesion. In contrast, transforaminal lumbar interbody fusion employs a foraminal approach with facet joint osteotomy, thereby reducing interference with the dural sac and preserving the posterior ligament complex, although it still results in damage to the paravertebral muscles.
With the advancement of minimally invasive spinal surgery, minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has emerged as a treatment option for lumbar degenerative diseases. This technique accesses the surgical field through the multifidus-longissimus muscle plane and offers several advantages, including reduced trauma, diminished blood loss, and accelerated recovery [15]. However, MIS-TLIF still necessitates the resection of significant muscle tissue, unilateral facet joints, partial laminae, and the ligamentum flavum. In contrast, percutaneous endoscopic lumbar interbody fusion (PT-Endo-LIF) technology maximally preserves laminae, facet joints, ligaments, and other spinal structures while ensuring sufficient operative space, thereby significantly minimizing surgical trauma.
Osman et al. [5] were the first to apply PT-Endo-LIF clinically for lumbar degenerative diseases, which prompted further investigations into this technique by other researchers. A meta-analysis [16] indicated that PT-Endo-LIF is associated with significantly less intraoperative blood loss compared to MIS-TLIF. Additionally, Ao et al. [17] reported that PT-Endo-LIF resulted in lower intraoperative bleeding, reduced postoperative drainage volume, and decreased hidden blood loss when compared to MIS-TLIF. They also observed markedly lower levels of serum creatine kinase and C-reactive protein. Importantly, PT-Endo-LIF significantly shortened postoperative ambulation time and hospital stay, thereby confirming that diminished surgical trauma and blood loss facilitate faster patient recovery. [17–18]
Published evidence indicates that PT-Endo-LIF requires a longer operative duration than MIS-TLIF [16–17]. The most time-consuming steps in PT-Endo-LIF are disc resection and endplate preparation. Despite advancements in endoscopic instrumentation that have significantly improved disc resection efficiency, endplate preparation remains a time-intensive process. In contrast to MIS-TLIF, where endplate preparation can be verified solely by palpation, PT-Endo-LIF necessitates a combination of palpation, direct endoscopic visualization, and fluoroscopy to confirm adequate endplate conditioning, thereby contributing to prolonged surgery time. In the present study, the PT-Endo-LIF group demonstrated significantly less intraoperative blood loss and an earlier postoperative ambulation time compared to the PLIF group (p < 0.05), underscoring a distinct advantage of PT-Endo-LIF over conventional open surgery. Conversely, PT-Endo-LIF was associated with a significantly longer operative time than PLIF (p < 0.05), a finding attributed to the steep learning curve of PT-Endo-LIF and the technical challenges posed by its limited surgical field of view and difficulties in managing the intervertebral space.
In this study, both groups demonstrated a significant improvement in VAS scores at postoperative day 7, 1 month, and 3 months compared to baseline (all p < 0.05). Additionally, ODI and JOA scores showed marked improvement at 1 and 3 months postoperatively (all p < 0.05). The PT-Endo-LIF group exhibited significantly lower VAS scores at postoperative day 7 and 1 month, along with superior ODI and JOA scores at 1 month, in comparison to the PLIF group (all p < 0.05). However, no significant intergroup differences were observed in VAS, ODI, or JOA scores at the 3-month follow-up (p > 0.05). Similarly, SF-36 scores were significantly elevated from baseline to 3 months postoperatively in both cohorts (p < 0.05), with no discrepancies between groups noted at that time point (p > 0.05). These findings suggest that PT-Endo-LIF provides medium-term efficacy comparable to conventional PLIF, while offering distinct advantages in alleviating early postoperative low back pain and enhancing patient-reported outcomes, consistent with previous studies. Zhao et al. [19] conducted a retrospective analysis of 78 patients with degenerative lumbar spinal stenosis. Their findings indicated that the PT-Endo-LIF group experienced significantly less intraoperative blood loss and shorter mean hospital stays compared to the MIS-TLIF group, along with superior clinical outcomes at the three-month mark. Similarly, Zhang et al. [20] assessed 62 patients with single-level lumbar spondylolisthesis and discovered that, in comparison to MIS-TLIF, PT-Endo-LIF was linked to reduced intraoperative bleeding but increased intraoperative fluoroscopic exposure. Furthermore, the PT-Endo-LIF group demonstrated greater improvements in VAS, ODI, and JOA scores during the early postoperative follow-up period.
The primary distinction between PT-Endo-LIF and MIS-TLIF is the former’s use of a percutaneous spinal endoscopic system, which facilitates foraminal access through a posterolateral approach with minimal bony resection. Intraoperative nerve root injury remains a significant concern during these procedures. Foraminoplasty, performed intraoperatively, can effectively enlarge the neural foramen, thereby creating sufficient space for subsequent instrumentation and reducing the risk of nerve root damage. Moreover, direct endoscopic visualization enables precise preparation of the vertebral endplates and accurate placement of interbody fusion devices, which further protects the spinal nerves and dural sac [21].
During the initial exploratory phase, PT-Endo-LIF is associated with a relatively high complication rate [16, 22]. This procedure entails a lengthy learning curve, necessitating that physicians possess substantial experience in endoscopic decompression prior to undertaking lumbar endoscopic fusion. In 2019, Kolcun et al. [23] reported on 100 patients who underwent small-channel transforaminal endoscopic fusion, of whom 4 experienced complications; notably, 3 of these cases involved patients in the early stages of the procedure. It is advisable, during the early implementation of this technique, to select patients with a single segment who do not require nerve decompression or only require limited decompression. Additionally, practitioners should first master endoscopic lumbar canal decompression and fusion techniques before gradually advancing to more complex lumbar endoscopic fusion cases.
A meta-analysis [16] indicated a complication rate of 10% for lumbar endoscopic fusion, which is comparable to the rate of 12.7% observed in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). The complications associated with percutaneous endoscopic lumbar interbody fusion (PT-Endo-LIF) primarily include dural tears, nerve injury or paralysis, endplate injury, screw loosening, and implant malposition, most of which are mild and responsive to conservative management. In this study, the incidence of surgery-related complications was 0% for PT-Endo-LIF and 4.55% for PLIF. The incidences of perioperative complications were 4.55% for PT-Endo-LIF and 13.6% for PLIF. The open incision involved in PLIF surgery is linked to a higher rate of infection. One patient in the PT-Endo-LIF group developed a postoperative urinary tract infection, which resolved with active anti-infective therapy; no other patients experienced severe complications such as surgical site infection or nerve root injury. These findings further substantiate the relative safety of the PT-Endo-LIF technique.
PT-Endo-LIF necessitates precise positioning and is linked to increased intraoperative X-ray exposure. Limitations in visual field due to channel design impede complete nerve decompression, while effective management of intervertebral space fusion remains a challenge. In the context of digital and intelligent orthopaedics, three-dimensional navigation, virtual reality technology, and robotics are poised for significant integration into lumbar endoscopic fusion surgery [2, 24]. Intraoperative spinal navigation has demonstrated the ability to reduce radiographic exposure, enhance the accuracy of pedicle screw placement, delineate the scope of decompression, and monitor the position and depth of fusion implants [24–27]. Currently, robotic systems are capable of performing pedicle screw insertions. The evolution of robotic decompression technology is anticipated to facilitate precise endoscopic robotic decompression in the future, thereby further minimizing surgical trauma, improving surgical efficiency, reducing complications related to neurovascular injury, and enabling safer, more minimally invasive, and low-radiation surgical procedures [28].
This study enrolled a relatively small sample of 44 patients, with 22 patients in each group, which may compromise both statistical power and the generalizability of the results. This limitation increases the likelihood that negligible random errors, such as random sampling errors, may be transformed into systematic biases, including selection and information biases. Additionally, controllable confounding factors may become unavoidable confounding biases. Collectively, these biases, along with low statistical power, may lead to false-positive or false-negative conclusions.
Nevertheless, this study solely evaluated the mid-term effectiveness over a brief 3-month follow-up period, which is evidently inadequate for appraising the enduring consequences of lumbar fusion surgery, such as fusion rate and adjacent segment degeneration. Being retrospective, it was hindered by inadequate patient follow-up adherence in real-world clinical settings. Consequently, future research necessitates extensive prospective studies with substantial sample sizes to overcome the constraints in assessing long-term effectiveness.
Conclusion
In summary, PT-Endo-LIF offers advantages such as minimal invasiveness, reduced bleeding, and expedited postoperative recovery. However, it also presents limitations, notably a steep learning curve that necessitates expertise in endoscopic lumbar decompression and familiarity with open fusion or MIS-TLIF techniques. Surgeons must adhere closely to established indications, select suitable fusion strategies based on their skill level, and prioritize surgical safety, efficacy, and the long-term outcomes of intervertebral fusion.
Severe lumbar spinal stenosis and grade II or higher lumbar spondylolisthesis represent relative contraindications for spinal endoscopic surgery, as they may lead to incomplete decompression or complicate reduction. Despite challenges such as heterogeneous techniques, a steep learning curve, high complexity, insufficient long-term fusion data, and a lack of standardized procedures, PT-Endo-LIF demonstrates significant application potential due to the continuous advancement of endoscopic instruments, technical refinement, and enhanced bone graft materials [29].
The credibility of this study is undermined by the lack of blinding, as both surgeons and patients were aware of the surgical methods employed. Additionally, the retrospective design, limited sample size, and short follow-up period highlight the need for extended monitoring to evaluate cage-related complications, such as subsidence, displacement, and dislodgement. Furthermore, large-scale multicenter studies are essential to validate these findings and offer more robust evidence.
Acknowledgements
Not applicable.
STROBE checklist statement
We have read the STROBE checklist, and the manuscript was prepared and revised according to the STROBE checklist.
Compliance with guidelines and regulations
All aspects of the research were carried out in strict accordance with relevant ethical guidelines and regulations. These include the Declaration of Helsinki for medical research involving human subjects. We have taken every measure to ensure that the rights, safety, and well - being of the participants were protected throughout the research process.
Abbreviations
- PT-Endo-LIF
Percutaneous transforaminal endoscopy-assisted lumbar interbody fusion
- PLIF
Posterior lumbar interbody fusion
- DLSS
Degenerative lumbar spinal stenosis
- VAS
Visual analogue scale
- ODI
Oswestry disability index
- JOA
Japanese Orthopaedic Association
- SF-36
Short-Form 36 Health Survey
- ALIF
Anterior lumbar intervertebral fusion
- LLIF
Lateral lumbar interbody fusion
- OLIF
Oblique lateral lumbar intervertebral fusion
- TLIF
Transforaminal lumbar interbody fusion
- MIS-TLIF
Minimally invasive transforaminal lumbar interbody fusion
- PELD
Percutaneous endoscopic lumbar discectomy
- OTLIF
Oblique lateral lumbar intervertebral fusion
Author contributions
Jie-Bin Huang wrote the main manuscript text; Yin-Feng Guo and Cheng-Zhao Li collected the data; Wei-Xiong Chen and Lei Pan contributed to the data analysis; Bai-Yong Zhu, Yu Lei, Wei-Dong Jiao, and Li-Bin Zheng collected the figures and references; Hou-Jun Xue conceived and designed the study; and all the authors read and approved the final manuscript.
Funding
This study was supported by the Medical Scientific Research Project of the Foshan Municipal Health Bureau, Guangdong (20240316).
Data availability
All the data generated or analysed during this study are included in this published article.
Declarations
Ethics approval and consent to participate
This study was Approved by the Medical Ethics Committee of Sanshui District People’s Hospital of Foshan (Relevant reference number: SRY-KY-2023036).The review process by this committee adhered to the highest standards of ethical review for research involving human subjects. Written informed consent was obtained from the patient for publication of this study and accompanying images.
Consent for publication
All data were fully anonymized, and no identifiable personal information is included in the manuscript. Written informed consent was obtained from the patient for publication of this study and accompanying images.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Contributor Information
Yin-Feng Guo, Email: 1248470852@qq.com.
Hou-Jun Xue, Email: xuehoujun2000@sina.com.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
All the data generated or analysed during this study are included in this published article.