Effect of MED-TLIF Combined with Percutaneous Pedicle Screw Fixation on Function and Spinal Pelvic Parameters in Patients with Lumbar Spondylolisthesis.

Background: Lumbar spondylolisthesis is a common clinical spinal lesion. The upper vertebral body of the patient is displaced relative to the lower vertebral body, causing spinal instability and nerve compression. The clinical manifestations are low back and leg pain, abnormal lower limb sensation, and intermittent rupture. In severe cases, cauda equina syndrome and paraplegia may occur. Minimally invasive spinal surgery has developed rapidly in recent years and become the preferred treatment for lumbar spondylolisthesis. Objective: The aim of this study is to investigate the clinical effect of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) combined with percutaneous pedicle screw fixation in the treatment of lumbar spondylolisthesis under microscope.
Methods: The clinical and surgical data of 106 patients with lumbar spondylolisthesis treated in our hospital were selected and divided into research group (56 cases) according to surgical methods (MIS-TLIF combined with percutaneous pedicle screw fixation). The other 50 patients were treated with traditional open percutaneous intervertebral foramen fusion (control group). The surgical trauma-related indicators, visual analog pain scale (VAS) scores before and after surgery, modified Japanese Orthopedic Association low back pain score (JOA), bone graft fusion effect, spinal pelvic parameters, and surgical complications of the two groups were statistically analyzed in detail.
Results: The incision length, intraoperative blood loss, operation time, and hospitalization time in the research group were lower than those in the control group, and the differences were statistically significant (P < 0.05). There was no significant difference in the VAS score and JOA score between the two groups before operation (P > 0.05). The VAS score and JOA score of the research group were lower than those of the control group on the first day after operation (P < 0.05). There was no significant difference in the VAS score and JOA score between the two groups at 1 month and 3 months after operation (P > 0.05). Six months, 12 months, and 18 months after operation, the bone graft fusion rates in the research group were 42.86%, 73.21%, and 94.64%, respectively, and those in the control group were 40.00%, 68.00%, and 92.00%, respectively, with no significant difference (P > 0.05). There was no significant difference in PI, PT, SS, LL, TK, LSJA, and SVA between the two groups before and 6 months after operation (P > 0.05). At 6 months after operation, the PT and TK values of the two groups were higher than those before operation (P < 0.05), and the SS, LL, LSJA, and SVA values of the two groups were lower than those before operation (P < 0.05). The complication rate of the research group was 3.57%, which was lower than 18.00% of the control group, and the difference was statistically significant (P < 0.05).
Conclusion: MIS-TLIF combined with percutaneous pedicle screw fixation in the treatment of lumbar spondylolisthesis has the same effect as traditional open surgery and has the same correction effect for spinal pelvic parameters, but it has the advantages of less trauma and fewer complications.

1. Introduction

Clinically, patients with mild lumbar spondylolisthesis can be treated with analgesic drugs, physical therapy, epidural injection, and other conservative treatment methods. However, for patients with moderate to severe lumbar spondylolisthesis, surgical treatment is needed [1]. The traditional open percutaneous intervertebral foramen fusion can fully relieve the pressure and pain, but its incision is large and the range of paravertebral tissue stripping is large, which has a negative impact on postoperative functional recovery [2]. Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) can complete the decompression and fusion of lumbar spondylolisthesis with the assistance of the disc mirror system. Compared with traditional open percutaneous intervertebral fusion, MIS-TLIF has the advantages of minimally invasive, but its decompression and fusion effect does not have advantages [3]. Therefore, MIS-TLIF is often used in combination with pedicle screw fixation. The traditional open pedicle screw fixation through the median approach requires extensive stripping and stretching of the paravertebral muscles for a long time, which may easily lead to neurovascular damage, massive bleeding, muscle necrosis and fibrosis, low back pain, and muscle atrophy [4, 5]. Percutaneous pedicle screw fixation is used to treat thoracolumbar fractures, which can effectively avoid tissue and muscle damage, shorten hospital stay, and reduce intraoperative blood loss. Compared with traditional open surgery, percutaneous pedicle screw internal fixation causes fewer complications and is more conducive to rapid postoperative recovery of patients [6-8]. Therefore, in order to find a better treatment plan and improve the therapeutic effect of patients with lumbar spondylolisthesis, this study used MID-TLIF combined with percutaneous pedicle screw fixation for the treatment of lumbar spondylolisthesis, and observed its clinical effect and its influence on the spinal and pelvic parameters of patients. The report is as follows.

2. Materials and Methods

2.1. Information

A total of 106 patients with lumbar spondylolisthesis in our hospital from May 2016 to August 2019 were selected for clinical retrospective analysis. The patients met the following inclusion criteria: (1) The main clinical manifestations of the patients before operation are low back pain, swelling and numbness of the lower limbs, and the patients are accompanied by severe intermittent claudication, which requires surgical treatment. (2) Patients ranged in age from 35 to 75 years. (3) Minimally invasive surgery and traditional open surgery were performed by the same group of medical staff in our hospital. (4) The degree of lumbar spondylolisthesis according to the Meyerding classification: I∼II° [1]. (5) Single-segment lumbar spondylolisthesis. (6) Patients and their families have been informed of the risks associated with surgery before surgery. (7) The programme meets the basic requirements of the Medical Ethics Committee. Exclusion criteria were as follows: (1) nonsteroidal anti-inflammatory drugs were taken in recent 2 weeks. (2) Patients with cerebrovascular diseases (cerebral hemorrhage, cerebral infarction, etc.). (3) Acute abdomen such as upper gastrointestinal ulcer, bleeding, gastrointestinal obstruction, and perforation. (4) Acute myocardial infarction, congestive heart failure. (5) with spinal tumors and tuberculosis. (6) Severe osteoporosis, scoliosis, and extremely narrow intervertebral space.

2.2. Surgical Method

MIS-TLIF combined with percutaneous pedicle screw fixation was used in the research group. The operator was used the C-arm machine to locate and make a transverse incision of about 2 cm at the location to separate the fascia and establish a working channel. Half of the lateral articular process bone was removed and the nucleus pulposus was resected under a microscope. The residual nucleus pulposus and cartilage plate were removed with a scraper. The prepared bone fragments were pushed into the anterior and bilateral intervertebral spaces to expand the intervertebral space. The PEEK anatomical cage was selected and fitted tightly in the middle or slightly anterior of the intervertebral space. Clean, place hemostatic gauze, and exit the working channel. The universal cannulated screw was placed in the same incision, and after the pedicle screw was inserted, the pre-bent rod was placed in the universal groove of the pedicle screw for locking and reduction. The contralateral pedicle screw rod was installed in the same way. The nut was tightened after conforming to the observed position of the C-arm machine. After the local drainage tube was placed, a needle incision was made to complete the operation.

The control group was treated with traditional open percutaneous intervertebral foramen fusion. A 10 cm incision was made in the posterior midline of the patient's lumbar spine, which was cut layer by layer to the deep fascia, and blunt dissection was performed to expose the lower lamina of the upper vertebral body, the upper lamina of the lower vertebral body, and the facet joints. The screw was placed at the vertical intersection of the horizontal line of the center of the lumbar transverse process and the lateral border of the superior articular process. Pedicle screws were placed after confirmation by X-ray. The articular process and part of the lamina on the affected side were excised, the nucleus pulposus was removed, the bone graft surface was cleaned, and the fracture particles were filled. A pre-curved titanium rod was mounted on the end of the pedicle screw and fixed. The surgical site was rinsed, a drainage tube was placed, and the incision was gradually closed, covered with a sterile dressing.

To prevent infection, patients in both groups were treated with antibiotics within 48 hours after surgery, and the duration of treatment was 24–48 hours. Glycerol fructose and dexamethasone were given to reduce nerve root edema, and nutritional nerve support treatment was given. The drainage tube was removed 2–4 days after operation. To guide patients with lumbar back muscle function exercise, severe activity was avoided.

2.3. Observation Indicators and Detection Methods

(1) Surgical trauma-related indicators in the two groups: incision length, intraoperative blood loss, operation time, and hospital stay. (2) Comparison of visual analog scale (VAS) scores before surgery, 1 day, 1 month, and 3 months after surgery [9]. The VAS scale is a subjective pain perception scale with a maximum score of 10 and a minimum of 0. The higher the VAS score, the more severe the patient's pain. (3) Modified Japanese Orthopedic Association low back pain score (JOA score) [10]. The highest JOA target function score is 29 points and the lowest is 0 points. The lower the patient's JOA score, the more severe the dysfunction. (4) Bone graft fusion rate: the number of successful fusions/total number of people. (5) Spine and pelvis parameters before and after surgery in the two groups: pelvic incidence angle (PI), pelvic tilt (PT), sacral tilt (SS), lumbar lordosis (LL), thoracic kyphosis (TK), lumbosacral angle Joint angle (LSJA), and sagittal balance (SVA).

The parameters of spine and pelvis were detected by X-ray film before operation and 6 months after operation. The patients were taken from a standing position, and the knee joint and hip joint were stretched. The full-length and lateral X-ray films of spine were taken. PI: the angle between the vertical dividing line of S1 endplate and the connecting line from the midpoint of S1 upper endplate to the midpoint of hip joint. PT: the angle between the midpoint of the upper endplate to the midpoint of the hip joint and the horizontal vertical line. SS : S1 endplate tangent and horizontal angle. LL : Angle between upper endplate tangent of L1 and lower endplate tangent of L5. TK : Angle between upper endplate tangent of T4 and lower endplate tangent of T12. LSJA: the angle between the upper endplate tangent of L5 and the posterior cortical tangent of S1, and the angle between the lower endplate tangent of L5 and the upper endplate tangent of S1. SVA : Horizontal distance between C7 plumb line and posterior superior sacral angle. All patients were performed by the same group of radiologists under the same X-ray machine.

2.4. Statistical Processing

SPSS 21.0 was used for data processing software. The measurement indexes such as VAS score and JOA score in this study were tested by normal distribution, which were in line with approximate normal distribution or normal distribution, and expressed as (x(_) ± s). The t-test was used for comparative analysis between groups. χ2 test was used for analysis and comparison of enumeration data. Test level α = 0.05, and P < 0.05 means the difference is statistically significant.

3. Results

3.1. Comparison of General Data between the Two Groups of Patients

The age, gender, blood pressure, spinal segment distribution, and other basic data of the research group and the control group were statistically analyzed, and the differences between the two groups were not statistically significant (P > 0.05), see Table 1 for details. Table 1 Comparison of general data of two groups of patients.

Table 1

Comparison of general data of the two groups of patients.

Normal information	Research group (n = 56)	Control group (n = 50)	t/χ2	P
Age (years)	55.10 ± 8.40	53.80 ± 7.00	0.860	0.392
BMI (kg/m2)	24.30 ± 2.60	24.00 ± 2.80	0.572	0.569
SBP (mmHg)	125.10 ± 8.40	123.70 ± 7.50	0.901	0.370
DBP (mmHg)	74.10 ± 6.80	76.00 ± 8.00	−1.321	0.189
Sex (%)			0.519	0.471
Male	32 (57.14)	32 (64.00)
Female	24 (42.86)	18 (36.00)
Meyerding type (%)			1.531	0.216
I	11 (19.64)	15 (30.00)
II	45 (80.36)	35 (70.00)
Diseased lumbar spine (%)			2.024	0.363
L3	18 (32.14)	11 (22.00)
L4	24 (42.86)	28 (56.00)
L5	14 (25.00)	11 (22.00)
Diabetes (%)			1.917	0.916
Yes	11 (19.64)	5 (10.00)
No	45 (80.36)	45 (90.00)
Coronary heart disease (%)			1.554	0.212
Yes	4 (7.14)	1 (2.00)
No	52 (92.86)	49 (98.00)

3.2. Comparison of Surgical Trauma Indexes between the Two Groups

The incision length, intraoperative blood loss, operation time, and hospitalization time in the research group were lower than those in the control group, and the differences were statistically significant (P < 0.05), see Table 2 and Figure 1 for details. Table 2 Comparison of surgical trauma indexes between the two groups (x(_) ± s). Figure 1 Comparison of surgical trauma indexes between the two groups. (A) Surgical incision length, (B) Intraoperative blood loss. (C) Operation time. (D) Hospital stay.

Table 2

Comparison of surgical trauma indexes between the two groups.

Group	n	Surgical incision length (cm)	Intraoperative blood loss (mL)	Operation time (min)	Hospital stay (d)
Research group	56	0.76 ± 0.23	41.80 ± 8.20	87.50 ± 9.60	7.20 ± 1.80
Control group	50	3.87 ± 0.81	98.60 ± 15.70	91.80 ± 8.80	10.60 ± 2.10
T		−27.530	−23.702	−2.394	−8.975
P		0.001	0.001	0.018	0.001

Figure 1

Comparison of surgical trauma indexes between the two groups. (a) Surgical incision length. (b) Intraoperative blood loss. (c) Operation time. (d) Hospital stay.

3.3. Comparison of the VAS Score and JOA Score between the Two Groups

There was no significant difference in the VAS score and JOA score between the two groups before operation (P > 0.05). The VAS score and JOA score of the research group were lower than those of the control group on the first day after operation (P < 0.05). There was no significant difference in the VAS score and JOA score between the two groups at 1 month and 3 months after surgery (P > 0.05), see Table 3 and Figure 2 for details. Table 3 Comparison of VAS score and JOA score between the two groups (x(_) ± s). Figure 2 Comparison of VAS score and JOA score between the two groups: (A)VAS Score, (B)JOA Scores.

Table 3

Comparison of the VAS score and JOA score between the two groups (x(_) ± s).

Index	Group	Preoperative	1 day after operation	1 month after operation	3 months after operation
VAS scores	Research group (n = 56)	6.49 ± 1.30	3.72 ± 0.95∗	1.88 ± 0.81∗	1.96 ± 0.77∗
	Control group (n = 50)	6.74 ± 1.38	5.10 ± 1.30∗	2.03 ± 0.86∗	2.12 ± 0.85∗
	T	−0.960	−6.285	−0.924	−1.017
	P	0.339	0.001	0.357	0.312
JOA scores	Research group (n = 56)	19.63 ± 2.84	11.30 ± 2.51∗	5.29 ± 1.60∗	5.50 ± 1.82∗
	Control group (n = 50)	19.11 ± 3.03	15.28 ± 2.84∗	5.81 ± 1.76∗	5.84 ± 1.67∗
	T	0.912	−7.660	−1.593	−0.998
	P	0.364	0.001	0.114	0.321

Figure 2

Comparison of the VAS score and JOA score between the two groups. (a) VAS Score. (b) JOA Scores.

3.4. Comparison of the Bone Graft Fusion Rate between the Two Groups

Six months, 12 months, and 18 months after operation, the bone graft fusion rates in the research group were 42.86%, 73.21%, and 94.64%, respectively, and those in the control group were 40.00%, 68.00%, and 92.00%, respectively, with no significant difference (P > 0.05). See Table 4 for details. Table 4 Comparison of bone graft fusion rate between the two groups (n (%)).

Table 4

Comparison of the bone graft fusion rate between the two groups (n (%)).

Group	n	6 months	12 months	18 months
Research group	56	24 (42.86)	41 (73.21)	53 (94.64)
Control group	50	20 (40.00)	34 (68.00)	46 (92.00)
χ 2		0.089	0.347	0.299
P		0.766	0.556	0.584

3.5. Comparison of Spine and Pelvic Parameters between the Two Groups

There was no significant difference in PI, PT, SS, LL, TK, LSJA, and SVA between the two groups before and 6 months after operation (P > 0.05). At 6 months after operation, the PT and TK values of the two groups were higher than those before operation (P < 0.05), and the SS, LL, LSJA, and SVA values of the two groups were lower than those before operation (P < 0.05), see Table 5 for details. Table 5 Comparison of spinal pelvic parameters between the two groups (x(_) ± s).

Table 5

Comparison of spine and pelvic parameters between the two groups (x(_) ± s).

Pelvic parameters	Preoperative		t	P	6 months after surgery		t	P
	Research group (n = 56)	Control group (n = 50)			Research group (n = 56)	Control group (n = 50)
PI (°)	61.83 ± 7.30	62.53 ± 8.41	−0.459	0.647	60.90 ± 8.58	61.73 ± 9.00	−0.486	0.628
PT (°)	36.40 ± 4.11	37.18 ± 4.78	−0.903	0.368	42.74 ± 4.42∗	41.58 ± 4.84∗	1.290	0.200
SS (°)	39.57 ± 3.61	38.83 ± 4.73	0.911	0.364	32.40 ± 3.75∗	34.02 ± 5.17∗	−1.860	0.066
LL (°)	51.85 ± 4.29	50.76 ± 5.50	1.144	0.255	40.76 ± 3.85∗	42.38 ± 4.92∗	−1.898	0.060
TK (°)	30.64 ± 2.18	31.51 ± 3.46	−1.566	0.120	37.28 ± 3.32∗	36.49 ± 3.63∗	1.170	0.245
LSJA (°)	6.11 ± 1.74	6.50 ± 2.00	−1.074	0.285	−3.86 ± 1.10∗	-4.15 ± 1.43∗	−1.177	0.242
SVA (mm)	78.54 ± 8.40	76.75 ± 8.77	1.073	0.286	51.54 ± 6.63∗	53.00 ± 8.25∗	−1.009	0.315

Compared with this group before surgery P < 0.05.

3.6. Comparison of Surgical Complications between the Two Groups

The complication rate of the research group was 3.57%, which was lower than 18.00% of the control group, and the difference was statistically significant (P < 0.05). See Table 6 for details. Table 6 Comparison of surgical complications between two groups.

Table 6

Comparison of surgical complications between the two groups.

Group	n	Incision infection	Lung infection	Loose internal fixation	Spinal cord injury	Complication rate (%)
Research group	56	0	2	0	0	2 (3.57)
Control group	50	2	4	1	2	9 (18.00)
χ 2						5.913
P						0.015

3.7. Typical Case Data

In Figure 3, A is a 56-year-old female patient with lumbar spondylolisthesis had lumbar pain and intermittent claudication. A, B, and C for preoperative X-ray, MRI, CT data, patients were diagnosed as L4 lumbar spondylolisthesis II°. D is the data of percutaneous pedicle screw surgery in the operation, and E and F are the results of review 1 week after the operation. It can be seen that the patient's lumbar spondylolisthesis is effectively corrected and the internal fixation is stable (see Figure 3).

Figure 3

(a) 56-year-old female patient with lumbar spondylolisthesis. The clinical signs are mainly lumbar pain and intermittent claudication. (a, b) and (c) are the X-ray, MRI, and CT data of the patient before the operation. The patient is diagnosed as L4 spondylolisthesis II. (d) is the data of the patient's percutaneous pedicle screw surgery during the operation. (e and f) are the results of the patient's 1 week postoperative review. It can be seen that the patient's lumbar spondylolisthesis has been effectively corrected and the internal fixation is stable.

4. Discussion

Surgical treatment of lumbar spondylolisthesis is aimed at spinal canal decompression, spondylolisthesis reduction, bone graft fusion and fixation to restore the normal sagittal sequence of lumbosacral region, and improve spinal balance and stability. In traditional open percutaneous intervertebral foramen fusion, paravertebral muscles and surrounding soft tissues need to be peeled off. Postoperative complications such as paravertebral muscle fiber scarification, fat liquefaction, and extradural scar can easily occur, resulting in low back pain. Procrastination can evolve into chronic low back pain [11]. The development of microendoscopic technology has greatly reduced the surgical trauma. MIS-TLIF can not only obtain sufficient decompression but also retain more stable structures and reduce the range of stripping paravertebral muscles. Since the surgical channel does not pass through the spinal canal, it has low risk of injury to the spinal environment, dural sac and nerve root, and has the advantages of small trauma, less bleeding and fewer complications [12]. MIS-TLIF combined with percutaneous pedicle screw fixation is completed once, which can simultaneously deal with spinal stenosis, interbody fusion, and fixation [3]. MED combined with percutaneous pedicle screw MIS-TLIF and traditional open TLIF can achieve good clinical results in the treatment of single-segment lumbar spondylolisthesis. The former has more advantages in intraoperative blood loss, postoperative drainage, shortening hospitalization time, and improving early postoperative low back pain [13].

In this study, it was found that compared with the traditional open percutaneous intervertebral foramen fusion treatment, the incision length, intraoperative blood loss, operation time, and hospitalization time of MIS-TLIF combined with percutaneous pedicle screw fixation treatment were lower, and the complication rate was also lower, suggesting that MIS-TLIF combined with percutaneous pedicle screw fixation in the treatment of lumbar spondylolisthesis had minimally invasive advantages such as small trauma, less complications, and rapid recovery, which was basically consistent with the existing research conclusions. This is due to the application of the MED endoscopic channel layer by layer expansion to the lesion target decompression, do not need to expose too much tissue, complete intervertebral fusion in small space, less damage to the surrounding tissue. Pedicle screw placement only need 2 cm small incision, avoid extensive stripping of paravertebral muscles, no damage to facet joints, joint capsule, resulting in significantly reduced trauma, more conducive to the rehabilitation of patients [14, 15].

The pain and activity disorders of patients with lumbar spondylolisthesis were related to the severity of the disease before operation and to the surgical trauma after operation. In this study, the VAS score was used to evaluate the degree of pain in patients. The JOA score was used to evaluate the degree of lumbar dysfunction in patients. It was found that MIS-TLIF combined with percutaneous pedicle screw fixation in the treatment of lumbar spondylolisthesis can reduce the degree of pain and activity disorder on the first day after operation. The degree of pain and activity disorder at 1 month and 3 months after operation and the bone graft fusion rate at 6 months, 12 months, and 18 months after operation were similar between the two groups. It is suggested that MIS-TLIF combined with percutaneous pedicle screw fixation in the treatment of lumbar spondylolisthesis has the same long-term effect as traditional open surgery. MIS-TLIF combined with percutaneous pedicle screw fixation can reduce the pain and movement disorder of patients earlier, and the early curative effect is better.

Spinal pelvic parameters are important parameters for evaluating lumbar diseases. The PI value is relatively stable after skeletal system development and is not related to posture and position. It is often used as an index to evaluate sacral-pelvic balance in clinic. The PI value of patients with lumbar spondylolisthesis was higher. PT, SS will change with posture changes, commonly used to evaluate the spatial location of the pelvis. The greater the LL/TK ratio, the more serious spinal instability. If LSJA is too large or too small, it can affect the mechanical balance of lumbosacral region. LSJA in normal population is negative, and LSJA in patients with lumbar spondylolisthesis becomes positive. SVA reflects the equilibrium state of sagittal plane [16-18]. In this study, the abovementioned indicators were detected, and it was found that the PT and TK values of the two groups at 6 months after operation were higher than those before operation. The SS, LL, LSJA, and SVA values were lower than those before operation, and there was no statistical difference between the two groups. The results suggest that MIS-TLIF combined with percutaneous pedicle screw fixation in the treatment of lumbar spondylolisthesis has the same correction effect as traditional open surgery for spinal pelvic parameters.

In summary, MIS-TLIF combined with percutaneous pedicle screw fixation in the treatment of lumbar spondylolisthesis has the same effect as traditional open surgery and has the same correction effect for spinal pelvic parameters, but has the advantages of less trauma and fewer complications.