Subjects:
This retrospective cohort analysis included a total of 146 patients with lumbar spinal stenosis and/or lumbosacral disc herniation. In the present study, fifty-six patients underwent MIS-TLIF [15, 16], and the other 90 patients underwent conventionalinvasive TLIF [1] (Table 1). All patients were recruited in SongJiang district central Hospital from October 2016 to September 2019. The study protocol was approved by Human Ethics Committees (Songjiang district central hospital, Shanghai, China; SJ2020-KY014). All subjects gave informed consent.
Table 1
Characteristic of patients undergoing MIS-TLIF and conventionalinvasive TLIF
|
MIS-TLIF
|
Conventionalinvasive TLIF
|
Number of subjects
|
56
|
90
|
Age (years)
|
55.5 ± 10.0
|
55.8 ± 9.9
|
Gender (male vs. female)
|
29 vs. 27
|
51 vs. 39
|
Duration (months)
|
17.4 ± 6.6
|
16.6 ± 6.6
|
BMI
|
23.5 ± 3.5
|
23.5 ± 3.4
|
Alcohol consumption
|
14/56 (25.0%)
|
17/90 (18.9%)
|
Current smoking
|
8/56 (14.3%)
|
13/90 (14.4%)
|
Preoperative complications
|
Hypertension
|
19/56 (33.9%)
|
27/90 (30.0%)
|
Diabetes mellitus
|
8/56 (14.3%)
|
11/90 (12.2%)
|
Heart disease
|
4/56 (7.1%)
|
5/90 (5.6%)
|
Chronic renal dysfunction
|
4/56 (7.1%)
|
4/90 (4.4%)
|
Involved lumbosacral level
|
L2-3
|
3/56 (5.4%)
|
8/90 (8.9%)
|
L3-4
|
22/56 (39.3%)
|
26/90 (28.9%%)
|
L4-5
|
22/56 (39.3%)
|
33/90 (36.7%)
|
L5-S1
|
9/56 (16.1%)
|
23/90 (25.6%)
|
Operative time (min)
|
140.4 ± 27.6
|
149.0 ± 38.9
|
Intraoperative blood loss (ml)
|
316.1 ± 83.1*
|
450.9 ± 77.3*
|
Drainage time (day)
|
1.9 ± 0.8
|
2.1 ± 0.8
|
Total amount of drainage
|
94.5 ± 48.4*
|
118.5 ± 56.3*
|
Measurements are expressed as the mean ± SD
*Statistically significant difference MIS-TLIF and conventionalinvasive TLIF
MIS-TLIF: Minimally invasive TLIF; TLIF: Transforaminal lumbar interbody fusion; BMI: Body mass index;
|
The inclusion criteria for patients in this study included (1) low back discomfort with referral of pain/paresthesias into lower limb and/or neuronal intermittent claudication (2) lumbosacral magnetic resonance imaging (MRI) or computer tomography (CT) that demonstrated single-level herniated disc, spinal stenosis or spondylolisthesis; (3) 6 months of regular conservative treatment without relief of symptoms; and (4) postoperative drain for at least one day. The exclusion criteria included previous spinal surgery, polyneuropathies, plexopathies, focal neuropathies, muscle disorders, cauda equina syndrome, scoliosis, spondylolisthesis, vertebral fractures, and other spinal pathologies. Furthermore, patients with incomplete medical records or lost to follow-up were excluded.
Surgical procedures:
Procedure for minimally-invasive TLIF
In the present study, the MIS-TLIF was performed by the same spine surgeon experienced in this technique. After the general anesthesia, the patient is placed in a knee-chest position, and intervertebral segment to treat is located by a positioning needle under the C-arm fluoroscopy. After performing a 2- to 3-cm skin incision approximately 3 cm away from spinous process, the guidewire was inserted along the wiltse approach into the facet joint, followed by placement of the expansion sleeve and assembly of the minimally invasive access system. The inferior and superior facets were resected under direct visualization, and then a discectomy was performed. A polyetheretherketone (PEEK) cage filled with harvested local was placed after endplate preparation. Bilateral pedicle screws were inserted through wiltse approach by minimally invasive access system, and both compression and fixation over the intervertebral space was completed afterward.
Procedure for conventionalinvasive TLIF
During the conventionalinvasive TLIF procedure [1], a midline incision was made. The soft tissues were cut in layers, and the paraspinal muscles were stripped from both sides of the spinous process to expose the lamina and the articular process. After the pedicle screw was implanted, the inferior and superior facets of the intended levels were resected under direct visualization, and then a discectomy was performed. A polyetheretherketone (PEEK) cage filled with harvested local was placed after endplate preparation, and compression over the intervertebral space was completed afterward.
Postoperative Management:
Antibiotics were given at postoperative 48 hours to prevent infection, and both hormone and non-steroidal anti-inflammatory drugs were not used in all patients in this study after operation. After one day of bed rest, the patients were allowed to walk with the protection of a waist brace. When the patients presented with postoperative persistent pain, the non-steroidal anti-inflammatory drugs were used until the Numerical Rating Scale(NRS)scores are lower than 3. A drainage tube was placed for 1–2 days. Patients were usually discharged from hospital 5–10 days after operation
Perioperative assessment:
Assessment of pain:
Both low back and lower limb pain in all patients were measured by NRS scores before, 3 days, 2 weeks and 6 months after operation. In this study, the persistent pain was defined as similar or more serious pain at the primary site or other sites in low back/lower limbs after operation. NRS scores is a continuous scale composed anchored by a score of zero, indicated no pain, and a score of 10, represented the worst pain.
Assessment of venous blood and drainage fluid samples:
Venous blood samples were obtained before, 1 day, 3 days and 6 days after operation, and the wound drainage fluid was collected from 1-3 days after operation according to the drainage time. For the blood samples, white blood cell (WBC) count, interleukin-6 (IL-6), C-reactive protein (CRP) and creatine kinase (CK) were measured. In the drainage fluid samples, both interleukin (IL)-1β and IL-6 were measured.
Statistical methods:
The measurements were analyzed using SPSS version 18.0 (IBM, USA). Measurements between the cases in two patient groups were compared by the independent t-tests, and the same statistical method was also used to analyze the measurements between the cases with or without persistent pain in both patient groups. The frequencies of postoperative persistent pain between two patient groups were compared by chi-square tests. The correlations between the extent of persistent pain and inflammation related markers in both blood and drainage fluid samples were analyzed by Pearson correlation coefficient analysis. In all instances, a P-value < 0.05 was considered significant.