DOI: https://doi.org/10.21203/rs.3.rs-1616936/v1
Background: The oblique lateral interbody fusion (OLIF) is a minimally invasive indirect decompression technique for the treatment of degenerative spinal disease. It is usually combined with posterior pedicle screw fixation to decrease perioperative complications.The purpose of this study was to compare the clinical efficacy of OLIF combined with lateral plate (LP) vs. combined with posterior pedicle screw (PS) fixation for the treatment of lumbar degenerative diseases (LDD).
Methods: The clinical data of 53 patients with lumbar degenerative diseases who underwent OLIF from May 2020 to December 2020 were retrospectively analyzed, 24 patients in OLIF+LP group and 29 paients in OLIF+PS group. We compared the clinical and radiographic outcomes between two groups. The operation time, blood loss, fusion rate and complications were recorded. The visual analog scale (VAS) score, Oswestry Disability Index (ODI), disc height (DH), foraminal height (FH) and cross-sectional area (CSA) were also evaluated.
Results: Fifty-three patients were followed up postoperatively for 13.2±6.5 (range 12-16) months. The operation time was 75.41±11.53 min in OLIF+LP group, which was much shorter than that in OLIF+PS group. Similarly, the blood loss was also much less in OLIF+LP group (39.55±5.32 VS 89.81±9.62 ml, P<0.01). In both of two groups, the VAS and ODI score had significantly decreased at the final follow-up compared to pre-operation. However, the OLIF+LP group suffered both less VAS scores and less ODI scores at 7 days (3.05±0.67 VS 4.55±0.39, P<0.01; 17.36±2.76 VS 22.80±6.02, P<0.01) after surgery than OLIF+PS group. Interestingly, these differences were both disappeared at one year after surgery. The DH, FH, and CSA had also improved by final follow-up. The total complication rate was 13.21% in this study, and there was no siginificant difference between the two groups, and the most common approach-related complication was end-plate injury.
Conclusions: OLIF+LP technique seems to be a valuable surgical option for single-segmental lumbar degenerative disease. It can achieve the similar clinical outcome with less damagment, compared with OLIF+PS technique.
Lumbar degenerative disease is a common and debilitating disease that causes pain and disability in elderly patients, it is a burden on our health care system. The prevalence of low back pain due to lumbar spondylosis is estimated to be 3.6% worldwide [1]. Meanwhile, the lumbar spine surgery rates have increased steadily over time [2]. Posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) have widely used to treat the degenerative disease of lumbar spine. However, extensive dissection of the paraspinal muscles as well as multifidus atrophy was the common criticism for the posterior lumbar surgery [3]. Many complications such as perioperative bleeding, dural tears, nerve root injury and postoperative low back pain have been reported [4]. It has been suggested that the perioperative complications rate of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) was still 15.6%, and the most common complication was durotomy (5.1%) [5].
Oblique lateral lumbar interbody fusion (OLIF) was first reported in 2012 by Silvestre et al, which using the natural space between the left lateral border of the abdominal aorta and the anterior medial border of the left psoas muscle, to avoiding the morbidity of traditional posterior surgery [6]. Moreover, minimally invasive OLIF technique can also significantly improve the coronal and sagittal balance of adult degenerative scoliosis (ADS) [7]. Excellent clinical results of this minimal invasive surgery has been already confirmed for treatment of ADS [8].
OLIF is commonly combined with supplemental posterior pedicle screw fixation (OLIF + PS) for the treatment of lumbar spine disease [9]. Zeng et al reported that the rate of complications was much lower with the usage of combined pedicle screw fixation [10]. Ohtori et al used posterior pedicle screws in all their patients who underwent OLIF and reported with good outcomes [11]. However, these procedures repuire two different incisions, increasing surgical risks and economic expenses. To the best of our knowledge, few studies have reported OLIF combined with lateral plate instrumentation (OLIF + LP) for the treatment of lumbar degenerative diseases. The purpose of this study was to compare the clinical and radiographic efficacy between the OLIF + LP and OLIF + PS group for the treatment of single-level degenerative disease of the lumbar spine.
This retrospective study was approved by the Ethics Committee of the authors’ affiliated institutions, the need for individual consent was waived by the committee because of the retrospective nature of the study. From May 2020 to December 2020, 53 patients who underwent single-segment OLIF surgery were identified and included in this study. The inclusion criteria were the presence of single-segmental lumbar degenerative diseases as follows: (1) lumbar degenerative disc diseases; (2) degenerative spondylolisthesis with Meyerding grade I; (3) failure to > 6 months of conservative treatment. The exclusion criteria were as follows: (1) severe osteoporosis (T score < 2.5); (2) multi-segmental degenerative lumbar spine diseases; (3) follow-up < 6 months; (4) severe lumbar degenerative spondylolisthesis (more than Meyerding grade II); (5) severe lumbar spinal canal stenosis which required direct posterior decompression. They were randomly grouped according to the order of admission, there were 24 patients in OLIF + LP group, and 29 patients in OLIF + PS group. The surgical manipulations of all the patients were completed by the same surgical team. The characteristics of the patients are shown in Table 1. There was no difference in demographic characteristics between the two groups.
| OLIF + LP (n = 24) | OLIF + PS (n = 29) | P | |
|---|---|---|---|
| Gender Male Female | 11 13 | 13 16 | 0.476 |
| Age (years) | 63.34 ± 10.20 | 61.95 ± 11.12 | 0.543 |
| Level (n) L2−3/L3−4/L4−5 | 3/8/13 | 4/10/15 | 0.398 |
| Operative time (min) | 75.41 ± 11.53 | 127.05 ± 5.62 | < 0.001 |
| Blood loss (ml) | 39.55 ± 5.32 | 89.81 ± 9.62 | < 0.001 |
| Hospitalization (day) | 7.51 ± 1.20 | 8.00 ± 0.71 | 0.609 |
The general OLIF technique has been described previously [12]. After general anesthesia, the patient was positioned in a lateral decubitus manner with left hip on the top. X-rays were taken to identify the target vertebral levels. A skin incision of 3–4 cm in length was made and the retroperitoneal space was accessed by blunt dissection along the retroperitoneal fat tissue. The psoas muscle was dissected with the index finger and retracted posteriorly, and the peritoneal sac was mobilized anteriorly. After discectomy, vertebral endplates were prepared, and an intervertebral cage filled with demineralized bone matrix was inserted.
In OLIF + LP group, after conventional OLIF procedure, a lateral plate instrumentaion was placed at the lateral part of the vertebrae. The screws were usually inserted upward and downward along the endplate so that to spare segmental vessels (Fig. 1). In the OLIF + PS group, after the general OLIF procedure, the patients were replaced in the prone position to undergoing posterior bilateral pedicle screw fixation via Wiltse approach, and the posterolateral fusion was not performed. All the patients were allowed to ambulate with a Boston brace on the second day postoperatively. The Boston brace was recommended for 3 months. All the patients were followed up for at least 12 months.
Routine X-ray, computed tomography (CT) and MRI were obtained for all patients. As shown in the Fig. 2, the radiological parameters, such as disk height (DH), foraminal height (FH), and cross-sectional area (CSA), were measured according to the methods reported by Sato [13]. All the imaging examinations were performed independently by two physicians. The intraclass correlation coefficients were > 0.85 for all variables. The Bridwell interbody fusion grading system was used for evaluation of fusion rate [14]. Grades I and II were considered as successful. Cage subsidence was defined as a cage sinking into an adjacent vertebral body by > 2 mm according on CT images [15].
Standardized and validated questionnaires, including the Visual Analog Scale (VAS) score for back pain intensity and the Oswestry Disability Index (ODI) score were administered to all the patients. We used a 10-point VAS, where 1 = least pain and 10 = worst pain. Clinical data were obtained preoperatively, and 7 days, 3 months, and 12 months postoperatively. Surgical characteristics and complications were also recorded.
Statistical analysis was performed using SPSS 18.0 for Windows (IBM, Armonk, NY, USA). Continuous data are presented as the means ± standard deviation, and were analyzed using Student’s t test. The level of significance was set at P < 0.05.
The mean operative time was 75.41 ± 11.53 min (range 53–110 min) in OLIF + LP group, and 127.05 ± 5.62 min (range 93–210 min) in the OLIF + PS group, the difference was statistically significant (P < 0.01). The intraoperative blood loss was 89.81 ± 9.62 ml in the OLIF + PS group, which is much more than that in OLIF + LP group (P < 0.01). There was no significant difference either in preoperative VAS or ODI scores between the two groups. As shown in the Fig. 3, the postoperative VAS and ODI scores were both improved significantly than before in each of groups. However, the OLIF + LP group suffered less VAS scores both at 7 days (3.05 ± 0.67 VS 4.55 ± 0.39, P < 0.01) and 3 months after surgery (2.35 ± 0.67 VS 3.25 ± 0.37, P < 0.05) than OLIF + PS group. Interestingly, this difference was disappeared at one year after surgery. Similarly, the difference of postoperative ODI scores between the two groups had statistical significant only at 7 days after the surgery (17.36 ± 2.76 VS 22.80 ± 6.02, P < 0.01). The clinical outcomes are summarized in Table 2.
| Parameters | Pre-op | Post-op 7-days 3-months 12-months |
|---|---|---|
| VAS OLIF + LP OLIF + PS | 7.13 ± 1.35 7.03 ± 1.66 | 3.05 ± 0.67*† 2.35 ± 0.67*† 2.12 ± 0.34* 4.55 ± 0.39* 3.25 ± 0.37* 2.15 ± 0.16* |
| ODI OLIF + LP OLIF + PS | 59.67 ± 6.92 60.27 ± 4.91 | 17.36 ± 2.76*† 14.75 ± 1.48* 10.42 ± 1.29* 22.80 ± 6.02* 15.06 ± 1.07* 10.50 ± 1.90* |
| *P < 0.05, Post-op vs. Pre-op in each group. † P < 0.05, OLIF + LP group vs. OLIF + PS group at each time point. ODI, Oswestry Disability Index; VAS, Visual Analog Scale. | ||
As shown in the Table 3, the DH, FH, and CSA were 8.96 ± 1.23 mm, 16.18 ± 3.49 mm and 88.95 ± 14.79 mm2 respectively before the surgery in the OLIF + LP group, and they were all increased significantly after the surgery (P < 0.05). Similarly, these three radiographic parameters were all improved significantly after operation in the OLIF + PS group. The rate of cage subsidence was 8.33% (2/24) in the OLIF + LP group, and 6.90% in the OLIF + PS group (2/29), the difference was not significant. There was no any cage retropulsion in either of groups during the follow-up. The fusion rate was 91.67% (22/24) in the OLIF + LP group, meanwhile 93.10% (27/29) in the OLIF + PS group at 12 months after surgery (P = 0.69). Images of typical cases are shown as Fig. 4 and Fig. 5.
| Parameters | Pre-op | Post-op |
|---|---|---|
| DH OLIF + LP OLIF + PS | 8.96 ± 1.23 8.66 ± 2.21 | 13.02 ± 8.83* 12.82 ± 7.35* |
| FH OLIF + LP OLIF + PS | 16.18 ± 3.49 16.35 ± 5.19 | 21.54 ± 2.12* 21.96 ± 3.14* |
| CSA OLIF + LP OLIF + PS | 88.95 ± 14.79 89.23 ± 12.18 | 126.53 ± 8.83* 127.12 ± 10.14* |
| *p < 0.05, Post-op vs. Pre-op in each group. DH, Disk Height; FH, Foraminal Height; CSA, Cross Sectional Area; | ||
The total complication rate was 13.21% (7/53) in this retrospective study. In the OLIF + LP group, two cases of L4/5 end-plate injury were noticed intraoperatively. Two patients with lumbosacral injury were observed in the OLIF + LP group. These patients had hip flexion weakness. Fortunately, they recovered within 3 months postoperatively. In the OLIF + PS group, one patient with leg weakness and two patients with end-plate injury were observed. No major vessel injuries or nerve root injuries occurred. No intervertebral space infections, cerebrospinal fluid leakage, vertebral body fracture or instrument failure were observed during the follow-up.
Lateral plate instrumentation constitutes an internal fixation system tailored for lateral and anterior surgical approaches. It increases the stability immediately after OLIF, and theoretically increases the fusion rate after surgery. Moreover, a single lateral incision can help avoiding the posterior muscle tissue injury, decreasing the potential risk of nerve damage and shortening the operation time. In this retrospective study, the postoperative radiograpgic parameters such as DH、FH and CSH were all improved than before in both of the groups. Undoubtedly, the clinical symptoms alleviated in all of the patients. However, the patients in OLIF + LP group had lower VAS and ODI scores after surgery than the OLIF + PS group, the destruction of posterior longitudinal complex during the pedicle screw fixation may be the main cause.
OLIF was reported as an relatively safe procedure through the transpsoas approach, allowing for psoas preservation, and avoids the vascular injury[6]. It has been reported to result in about 30.0% average increase in the neural foramen area and a 30.2% median increase in the cross-sectional area of the dural sac [12–13]. However, the occurrence of complications is inevitable, and it has been reported to range from 3.7–66.7% [16]. In a study directed by Abe, intraoperative complications occurred in 44.5% of the patients, while only 4.7% of postoperative complications occurred with OLIF [17]. The most common complication was endplate fracture followed by the transitory weakness of the psoas muscle and transient neurological symptoms. Zeng et al reported that the endplate damage, cage sedimentation and shifting were the three most common complications of OLIF [10]. In their study, the complication rate was 36.26% in the OLIF stand-alone group, which was much higher than that in OLIF combined with pedicle screw group (29.86%). Up to date, the pedicle screw instrumentation was commonly applied for stabilization after OLIF because they were considered to provide the most rigid fixation of spine [18]. However, the selection between unilateral pedicle screw (UPS) and bilateral pedicle screw (BPS) fixation still remain controversial in lumbar spine surgery. Wen et al compared the clinical and radiological outcomes between the BPS and UPS fixation group who underwent OLIF, they suggested that the OLIF combined with UPS fixation is an effective and reliable option for single-level lumbar diseases [19].
Obviously, posterior pedicle screw fixation decreases the incidence of sedimentation, but the increased cost, prolonged operation time, and greater damage to the posterior muscle tissue should be taken into consideration. Blizzard et al first reported the lateral position technique for percutaneous pedicle screw placement following LLIF or OLIF, however, the 2.8% rate of re-operation for malpositioned screws is slightly higher [20]. Lateral pedicle screw instrumentation after anterior lumbar interbody fusin (ALIF) or lateral lumbar interbody fusion (LLIF) has been previously reported to avoiding the disadvantages of posterior pedicle screw fixation [21–22]. In a retrospective study of 65 patients with lumbar DDD diseases, Xie et al reported that lateral pedicle screw fixiation combined with OLIF is a safe and effective surgical option that results in less operation time and less blood loss [23]. Liu et al combined OLIF with anterolateral screw and rod instrumentation to achieve good clinical result, and a fusion of approximately 95% was reported in their study [24]. Moreover, the combination of OLIF and lateral screw instrumentation was also reported as an effective and safe option for the treatment of degenerative spine deformity [25]. However, there are few report about the usage of lateral plate fixation system combined with OLIF. In the current study, the oblique lateral fixation system was used with OLIF procedure, it was a very convenient and safe method allowed for one-stage intervertebral fusion and instrumentation through a single small incision.
A major concern is that the lateral instrumentation may not be strong enough to maintain the spinal stability and prevent subsidence of the interbody cages. The biomechanical strength of the lateral plate fixation system should be considered. Compared with the stand-alone technique, lateral plate instrumentation significantly decreased the lateral bending and axial rotation ROM, although it did not alter the ROM in flexion-extension [26]. The cage combined with a lateral plate was not significantly different from that with bilateral pedicle screws in lateral bending. In another biomechanical study, the two-hole lateral plate and bilateral pedicle screw fixation both significantly limited ROM in all loading planes, and they were recommended when used in two-level lumbar fusion with laterally placed cages [27]. In a three dimensional finite element study, Liu et al suggested that the lateral plate and screws could not provide sufficient biomechanical stability for multilevel lateral interbody fusion [28]. However, in a cadaveric biomechanical study, Lai et al suggested that unilateral pedicle screw and lateral plate may provide sufficient biomechanical stability for multilevel LLIF [29]. In the present study, we only applied the lateral plate instrumentation in the patients with one-segmental degenerative disease of the lumbar spine. Moreover, the grade II or more serious lumbar spondylolisthesis patients were also excluded. No instrumentation failure occurred in our study.
The complication of lateral plate instrumentation is another concern. The vertebral body fractures in patients who received supplemental lateral plating or pedicle screw fixation during LLIF were reported [30–31]. The reason might be that a fracture propagates through the screw hole from the fixed-angle anterolateral plate, resulting in a coronal plane fracture especially in osteoporotic cases. The coronal plane vertebral fracture also occurred in osteoporotic patients who underwent XLIF combined with XLP lateral instrumentation, and the unilateral pedicle screw instrumentation does not prevent this complication [32]. Brier-Jones et al speculated that violation of the epiphyseal ring or subchondral bone by plate-anchoring screws may contribute to the coronal vertebral body fractures [33]. Kepler et al suggested that the unbalanced distribution of compressive stress is another important factor leading to vertebral fractures [30]. In the present study, there were no complications related to the lateral plate fixation system. Several factors may explained it. First, all the patients admitted were single-segmental lumbar degenerative disease; Second, the cages used for OLIF were much larger, which located in the II-III area of the vertebral body, and the stress distribution of the whole vertebral body was even. Third, the use of a spine brace was advised for the first three months after surgery. Similarly, in our another retrospective study, there was no any vertebral fracture or instrumentation failture case happened, and OLIF + LP technique can achieves good radiographic and clinical results [34]. However, Ge et al suggested that the additional lateral plate fixation does not appear to be more effective to prevent cage subsidence in the oblique lumbar interbody fusion, compared with stand-alone technique [35]. In their study, the follow-up period was only 6 months and was lack of OLIF + PS control group.
The present study had some limitations. First, We performed a retrospective study with a small sample size, and the duration of follow-up was short. Second, only the patients who suffered single-segmental lumbar spine disease were included, whether this technique is suitable for patients with multi-segmental degenerative disease of the lumbar spine is unknown. Randomized control trials with large samples are needed to verify its pros and cons.
OLIF + LP technique seems to be a valuable surgical option for single-segmental lumbar degenerative disease, it can achieve much better clinical outcomes than OLIF + PS group.
Acknowledgements: This study was sponsored by the Medical Health Science and Technology Project of Zhejiang Province (2021KY349) and the Science and Technology Bureau Project of Huzhou (2020GY08). No benefits in any form have been or will be received from any commercial party related directly and indirectly to the subject of this manuscript.
Disclosure statement：The authors declare that they have no conflict of interest.
Ethics approval and consent to participate
This study had been approved by the Ethics Committee of the First People’s Hospital affiliated to the Huzhou University Medical College. All methods were carried out in accordance with relevant guidelines and regulations. The informed consent to participate in the study should be obtained from all the patients.
Consent for publication
Not applicable
Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
Competing interests
The authors declare that they have no competing interests
Funding
This study was sponsored by the Medical Health Science and Technology Project of Zhejiang Province (2021KY349) and the Science and Technology Bureau Project of Huzhou (2020GY08).
Authors’ Contributions
HDL had full access to all of the data in the study and took responsibility for the integrity of the data and the accuracy of the data analysis. JKM and XHZ were highly involved in the planning and execution of this study. Furthermore, LZ was highly involved in the acquisition of data and in the process of data interpretation. All authors read and approved the final manuscript.