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Outcome of Percutaneous Transforaminal Endoscopic Lumbar Decompression for Multisegment Lumbar Spinal Stenosis and the Effect on VAS Scores

Purpose To investigate the efficacy of percutaneous transforaminal endoscopic lumbar decompression (PTED) in the treatment of multisegment lumbar spinal stenosis (LSS) and its effect on VAS scores. Methods 126 patients with multisegment LSS admitted between August 2017 and August 2021 were selected and divided into the PTED group and the traditional open surgery group (TOS group) according to the different treatment methods. There were 70 cases in the PTED group, treated with PTED, and 56 cases in the TOS group, treated with traditional open surgery. The clinical outcomes, the preoperative and postoperative pain visual analogue scale (VAS), the Oswestry disability index (ODI), the SF-36 quality of life questionnaire scores, the perioperative indicators (operative time, days in hospital, intraoperative blood loss), the postoperative complications, and imaging data were compared between the two groups. Results After the operation, the excellent and good rate in the PTED group (91.43%) was significantly higher than that in the TOS group (75.00%) (P < 0.05). At each time after the operation, the VAS and ODI scores of the two groups were lower than those before the operation, and the VAS scores of the PTED group at 1 day and 3 months after operation were lower than those of the TOS group, and the ODI scores of the PTED group at 3 months after operation were lower than those of the TOS group (P < 0.05). 3 months after the operation, the SF-36 scores in both groups were higher than those before the operation, and those in the PTED group were higher than those in the TOS group (P < 0.05). The operation time and days in hospital in the PTED group were shorter than those in the TOS group, and the intraoperative dominant blood loss and recessive blood loss were less than those in the TOS group (P < 0.05). The total incidence of complications in the PTED group (15.71%) was significantly lower than that in the TOS group (32.14%) (P < 0.05). Conclusion Both PTED and traditional open surgery are effective in treating patients with multisegmental LSS, and both show positive postoperative changes in all indicators, but the former has more promising near -term results in improving lumbar spine pain, function and quality of life than the latter, and has the advantages of less trauma, less bleeding, and fewer complications.


Introduction
Lumbar spinal stenosis (LSS) mostly occurs in the elderly, aged 60-70, and more in women than in men [1]. It refers to the narrowing of the spinal canal, nerve root canal, and intervertebral foramen caused by compression of bones and soft tissues, resulting in the corresponding clinical symptoms. e pathogenesis of the disease is not completely clear. It may be that when spinal canal stenosis and nerve root compression occur, the horizontal area of the central spinal canal and nerve root canal decreases due to the stretching activity of the lumbar spine, further compressing the surrounding venules, resulting in local congestion and ischemic nerve damage [2,3]. Surgical treatment can relieve the compression, increase the space of the diseased segments, and theoretically alleviate the symptoms. However, there is great controversy about which surgical method to choose for treatment [4]. Open posterior laminectomy, decompression of the lumbar spine, and interbody fusion are commonly used in traditional operations. Although the decompression is complete, the surgery is more traumatic and requires prolonged postoperative bed rest. Moreover, this procedure requires stripping the paravertebral muscles and removing part or all of the lamina, which may lead to complications of medical origin such as lumbar instability and epidural scar formation, affecting the clinical outcome to a certain extent [5,6]. Percutaneous transforaminal endoscopic lumbar decompression (PTED) is one of the most popular minimally invasive spinal techniques in recent years, with the unique advantages of being performed under local anesthesia with a small surgical incision (approximately 7 mm), short duration, minimal bleeding, no posterior ligamentous structures or muscle damage, and rapid recovery, which provides a viable treatment option for patients with underlying disease or who are too old to tolerate open surgery [7,8]. However, due to the relatively complex causative factors of LSS, the relatively limited field of view of endoscopic surgery, and the long learning curve for the operator, there is a strong clinical need to analyse the efficacy and complications of PTED in the treatment of LSS. is study compares and analyses the efficacy of PTED versus traditional open surgery for a multisegmental LSS and the effect on VAS scores. It is reported as follows.

General Materials.
130 patients with multisegment LSS admitted between August 2017 and August 2021 were retrospectively analysed and divided into the PTED group and the traditional open surgery group (TOS group) according to the different treatment methods. Follow-up was carried out for 6 months via Internet questionnaires, telephone, and outpatient clinics. 3 patients failed to complete follow-up due to a change of contact and home address during this period, and 1 patient died of natural causes. 126 cases in total received complete follow-up information.
ere were 70 cases in the PTED group, treated with PTED, and 56 cases in the TOS group, treated with traditional open surgery.

Inclusion
Criteria. ① A clear history of low back and leg pain with intermittent claudication and radiating pain in the lower limbs. ② Multiresponsible segmental LSS confirmed by CT and MRI data, consistent with the patient's symptoms and signs. ③ ose who had failed to respond to strict conservative treatment for more than 3 months. ④ ose who voluntarily accepted surgical treatment in our hospital and met the conditions for regular follow-up.

Exclusion
Criteria. ① X-rays suggesting lumbar instability, lumbar spondylolisthesis, and scoliosis. ② Patients who had previous surgery on the same segment of the lumbar spine. ③ ose with lumbar spine infections, tumours, tuberculosis, etc. ④ ose with a single responsible segment LSS. ⑤ ose who presented with cauda equina syndrome. ⑥ ose with bleeding tendencies and organ dysfunction. ⑦ ose with missing follow-up information.

e PTED Group Was Treated with PTED.
All patients underwent the procedure under local anesthesia without any water fasting and were instructed to urinate. Preoperative psychological counselling and routine skin preparation were performed and prophylactic intravenous antibiotics were administered half an hour before surgery. e operation was performed, in a lateral position, with the symptomatic side on the top, and the waist of the healthy side was padded up (remove the cushion after successful catheterization) to stabilize the position and expand the intervertebral foramen. e anesthetic needle entry point was determined according to the patient's body type and preoperative lumbar frontal and lateral radiographs. Local anesthesia was performed and the needle position was adjusted under intermittent fluoroscopy, with the needle tip finally placed at the tip of the superior articular process at the surgical segment. e puncture needle was replaced with a locating needle along the trajectory, and the locating needle was used to penetrate the superior articular process bone, after which the tip of the needle was gradually traveled to the posterior aspect of the superior endplate of the vertebral body below the surgical target space, keeping the tip of the locating needle close to, but not above, the posterior midline on the orthoptic image. Along the puncture needle trajectory, a 6 mm and 8 mm bone drill were shaped to enlarge the intervertebral foramen and the lateral saphenous fossa, respectively, and the trocar was then placed. After C-arm fluoroscopy had determined the position of the working trocar, endoscopic decompression was performed. e proliferative and hypertrophic ligamentum flavum and posterior longitudinal ligament were removed, the degenerative intervertebral disc was removed, and the proliferative osteophyte was removed by osteotome to complete the all-around decompression of the nerve root. During the operation under the microscope, radiofrequency hemostasis was applied, there was continuous flushing with normal saline, and patients were regularly communicated to determine their status. Surgical completion criteria are as follows: the dural sac was full and pulsating, and the ventral space was sufficient; the blood supply of the nerve root was improved; there was no bony compression in the proximal and distal nerve roots; straight leg elevation or femoral nerve traction test was negative; when the affected limb was moved, the patient felt better; under the microscope, there was no extrusion of intervertebral disc tissue, and sometimes nerve root sliding could be seen. After the operation, the drainage tube was left for 24 h, the cannula was withdrawn, and the incision was sutured.

TOS Group Was Treated with Traditional Open Posterior Laminectomy and Decompression of Lumbar Spine and
Interbody Fusion. After general anesthetic intubation, the patient was placed prone, a posterior median incision was made with the patient's lesioned segment as the centre, the skin, subcutaneous tissue, and fascia at the edge of the supraspinous ligament were incised in turn, the sacrospinous muscles on both sides of the spinous process were separated, and the decompression-fixed segment was fully exposed. e pedicle screw was inserted, the lower edge of the upper lamina and all the upper edges of the lower lamina were removed, the articular process around the bone window and the cohesive part of the hyperplasia of the ligamentum flavum was removed, the lateral recess was expanded sneakily, and the nerve root was exposed and released. After that, the nerve root and dura mater were pulled to the inside, the intervertebral disc and cartilage endplate were completely removed, the appropriate intervertebral fusion cage was selected for intervertebral bone grafting and fusion, and the nail rod was connected and fixed under pressure. e incision was sutured layer by layer, the wound drainage tube was placed, and the wound was bandaged after the operation. In order to avoid postoperative instability, all patients in the open group underwent interbody fusion.

Assessment Indicators
(1) Clinical outcomes: patients walking pain-free for >5 min or >200 m after the operation were regarded as excellent; patients walking pain-free for 3∼5 min or 150∼200 m after the operation were regarded as good; patients walking pain-free for 1-2 min or 100∼149 m after the operation were regarded as moderate; patients walking pain-free for <1 min or <100 m after the operation were regarded as poor. Excellent and good rate � (excellent + good)/total number of cases × 100%. (2) Visual analogue scale (VAS) score of pain: before the operation, 1 day after the operation, and 3 and 6 months after the operation, the pain level of both groups was assessed by VAS. e total score of 10, with higher scores indicating more severe pain. (3) Oswestry disability index (ODI) : the ODI was used to assess the degree of functional recovery in both groups before the operation and at 3 and 6 months after the operation. It consisted of 10 aspects, such as pain intensity, lifting, walking, and social life. Each item was scored from 0 to 5, with a total score of 50. e scoring method was actual score/highest possible score × 100%. e higher the score, the worse the functional recovery.

Statistical
Methods. e statistical software SPSS 22 was used for data analysis. e measurement data were described by the mean ± standard deviation, and a t-test was used for pairwise comparison between groups. e count data was described as (%), and comparisons were made using the χ 2 test. e two-sided test (P < 0.05) was statistically significant.

Comparison of Baseline Information between the Two Groups.
ere was no significant difference between the two groups when comparing baseline information (P > 0.05). (Table 1).

Comparison of Clinical Outcomes between the Two
Groups. After the operation, the excellent and good rate in the PTED group (91.43%) was significantly higher than that in the TOS group (75.00%). e difference was significant (P < 0.05). (Table 2).

Comparison of VAS Scores between the Two Groups.
At each time after the operation, the VAS scores of the two groups were lower than those before the operation, and the VAS scores of the PTED group at 1 day and 3 months after the operation were lower than those of the TOS group. e difference was significant (P < 0.05). (Figure 1).

Comparison of ODI Scores between the Two Groups.
At 3 and 6 months after the operation, the ODI scores of the two groups were lower than those before the operation, and the ODI scores of the PTED group at 3 months after the operation were lower than those of the TOS group. e difference was significant (P < 0.05). (Figure 2).

Comparison of SF-36 Scores between the Two Groups.
3 months after the operation, the SF-36 scores in both groups were higher than those before the operation, and those in the PTED group were higher than those in the TOS group. e difference was significant (P < 0.05). (Figure 3).

Comparison of Perioperative Indicators between the Two
Groups.
e operation time and days in hospital in the PTED group were shorter than those in the TOS group, and the intraoperative dominant blood loss and recessive blood loss were less than those in the TOS group. e difference was significant (P < 0.05). (Figure 4).

Comparison of Intraoperative and Postoperative Complications between the Two Groups.
e total incidence of complications in the PTED group (15.71%) was significantly Evidence-Based Complementary and Alternative Medicine lower than that in the TOS group (32.14%). e difference was significant (P < 0.05). (Table 3).

Discussion
e typical symptoms of LSS are sciatica and lower back pain, which can be associated with sensory abnormalities [9]. Intermittent claudication is one of its main clinical features and is characterised by pain, numbness, and weakness during walking, which may be relieved by rest and reappear when walking again, and so on. e etiology of the disease is complex, and the nerve compression is often not a single factor. Many factors, such as intervertebral disc degeneration and bulging, small joint hyperplasia and cohesion, ossification of the posterior longitudinal ligament, hypertrophy of the ligamentum flavum, and formation of osteophytes at the posterior edge of the vertebral body, participate in the pathological process of LSS [10][11][12]. For those who fail to respond to conservative treatment, surgery is the best option to maintain spinal stability, relieve nerve root compression, and relieve symptoms and signs. is study compares and analyses the effects of different surgical approaches applied to multisegment LSS on patient outcomes and VAS scores. e results showed that after the operation, the excellent and good rate of patients in the PTED group (91.43%) was significantly higher than that in the TOS group (75.00%), which was generally consistent with the excellent and good rate of 90.6% in the results of the study by Li et al. [13]. is suggests that PTED has unique advantages over traditional open procedures for the treatment of multisegment LSS. e VAS score can be used as a quantitative reference for the painful condition of lumbar spondylosis [14]. e ODI can be used as a quantitative indicator of low back pain dysfunction and is important in reflecting functional recovery [15]. In this study, pain conditions, functional impairment, and quality of life were monitored at multiple time points for multisegment LSS. e results showed that VAS, ODI, and SF-36 scores were better than preoperative scores in both groups et al. l postoperative time points. and VAS scores were better than TOS group in the PTED group at     Evidence-Based Complementary and Alternative Medicine 1 day after the operation, and VAS, ODI, and SF-36 scores were better than TOS group in the PTED group at 3 months after the operation. e above suggests that the use of PTED for multisegmental LSS can significantly reduce postoperative pain, promote functional recovery, and improve quality of life compared to traditional open surgery. e results also showed that the VAS and the ODI scores of the patients showed significant improvement as the treatment time was extended, and at 6 months after the operation, the VAS and the ODI scores of the two groups basically normalized, and the difference was not statistically significant in any comparison. is indicates that regardless of the abovementioned procedures, the improvement in pain levels and lumbar spine dysfunction becomes more pronounced as the duration of treatment increases and that patients' index scores for each item can largely return to normal values after 6 months of surgical treatment.
Traditional open surgery is more widely used and can effectively reduce pressure on the nerve root canal and lateral saphenous fossa, while eliminating the need for allograft bone and artificial bone assistance and accelerating contact between the bone bed and the lateral ophthalmic fossa [16]. However, this procedure is more invasive, has more complications, and is slower to heal postoperatively. PTED is a minimally invasive procedure with the advantage of a clear intraoperative view, which reduces intraoperative injuries and complications. It is also possible to achieve effective decompression of the nerve root, relieving clinical symptoms, and with a rapid postoperative recovery, patients can return to work and life early [17,18]. However, the procedure is demanding, and the operator's level of puncture positioning and microscopic manipulation can directly affect postoperative outcomes and associated complications, making the use of PTED for LSS somewhat challenging [19]. In this result, the PTED group had a shorter operative time and days in hospital than the TOS group and less intraoperative blood loss than the TOS group. e overall complication rate for patients in the PTED group was significantly lower than in the TOS group. ese reaffirm the importance of PTED in the treatment of LSS, significantly reducing operative time, intraoperative bleeding, accelerating postoperative recovery, and reducing complications.
As most patients with LSS are elderly, patients have more severe bone degeneration and are prone to osteoporosis and other degenerative joint pathologies [20]. PTED treatment combines traditional surgery with endoscopic surgery, which is performed under local anesthesia. It is suitable for elderly patients with multiple system diseases who are not suitable for general anesthesia, and it can minimize the impact of surgery and anesthesia on patients. However, as an invasive procedure, there are specific complications associated with PTED for LSS. For example, 3 patients in the PTED group in this study had refurbishment due to incomplete intraoperative decompression. It is considered that this may be related to the poor intraoperative placement of the tube, which limits the scope of the microscopic view and the range of instrumentation. In addition, the residual nucleus pulposus and the pressure factors that are not easy to  Figure 4: Comparison of perioperative indicators between the two groups. Note: * means the difference between groups is statistically significant. Evidence-Based Complementary and Alternative Medicine find in the lateral recess can also cause the nerve root to be continuously compressed, resulting in no obvious relief or even aggravation of symptoms [21,22]. It can be seen that it is necessary to do detailed and accurate puncture route planning before PTED. In summary, both PTED and traditional open surgery are effective in treating patients with multisegmental LSS, and both show positive postoperative changes in all indicators, but the former has more promising near-term results in improving lumbar spine pain, function, and quality of life than the latter, and has the advantages of less trauma, less bleeding, and fewer complications.
Data Availability e data used or analysed in the current study are available from the corresponding author.

Conflicts of Interest
e authors declare that there are no conflicts of interest.