With the increasing aging in China, the incidence of lumbar degenerative diseases has increased, and DLS is one of the highly prevalent types of lumbar degenerative diseases[9, 10]. The pathogenesis of DLS is poorly defined, the etiology is complex, and it is often combined with lumbar scoliosis, lumbar spinal stenosis, and osteoporosis. Clinically, it can produce intractable lower back and hip pain, intermittent trekking, and radicular symptoms in the lower extremities. Although the symptoms can be somewhat controlled after some conservative modality interventions such as physical therapy, they are prone to recurrence. Some studies have shown[11, 12] that about 10% of patients with DLS have indications for surgery. When long-term conservative treatment is unsuccessful, surgery is often required to completely relieve the dysfunction.
In traditional surgical treatment, most vertebral fusion is used such as open surgery ALIF, PLIF, and minimally invasive surgery TLIF, XLIF, and DLIF[13–17]. The most classic PLIF procedure is capable of decompressing the spinal canal directly, correcting the anterior lumbar convexity angle, resetting the slipped vertebral body, and restoring a certain height of the vertebral space. The lumbar stability is enhanced by the posterior nail bar system, which improves the stability of the fusion. However, this procedure destroys the stability and integrity of the posterior lumbar column, causing irreversible damage to the small joints and the posterior lumbar complex, which in turn strains the dura mater and nerve roots, which inevitably leads to complications such as adjacent vertebral disease, nerve injury, increased operative time and intraoperative bleeding. The OLIF procedure, officially named by Silvestre et al. The procedure establishes working through the gap between the psoas major muscle and the abdominal aorta channel, which greatly reduces the occurrence of complications and has been used as a new means of treatment for lumbar spondylolisthesis[18, 19]. In patients with DLS, there are more cases of osteoporosis and poor bone condition, and the biomechanical strength of OLIF Standalone is often inadequate, which requires posterior small-incision nail rod internal fixation to compensate for this deficiency. There is no definitive answer to the question of whether to perform OLIF Stand alone or open posterior fusion for DLS. The need for anterior fusion and posterior fixation for superior union remains controversial. The author used OLIF combined with Wiltse access pedicle screw fixation to treat single-level DLS with good recent clinical results. This procedure is less invasive, has fewer complications, promotes early functional recovery, shortens hospitalization time, and improves the quality of life.
Advantages Of Olif Combined With Wiltse Approach Pedicle Screw Fixation For Single-level Dls
The principles of treatment for single-level DLS need to revolve around various aspects of decompression, bracing, repositioning, stabilization, balance, and complications. Simple OLIF cannot meet this and conventional PLIF has certain shortcomings. Yang SL et al.used OLIF combined with Wiltse approach pedicle screw fixation for DLS, yielding effective postoperative correction of the coronal Cobb angle (19.6° ± 4.8° vs 6.9° ± 3.8°, P < 0.05), sagittal spine axis (4.3 ± 4.3 vs 1.5 ± 1.0 cm, P < 0.05), anterior lumbar convexity angle (29.4° ± 8.6° vs 40.8° ± 5.8°, P < 0.05), significant improvement in lumbar and leg pain and functional scores, high fusion rate, and good stability.
In the present study, the author used OLIF combined with Wiltse access pedicle screw fixation to treat patients with single-level DLS. The results showed that the operative time was (91.46 ± 6.83) min, intraoperative bleeding was (92.92 ± 9.55) ml, postoperative drainage was (31.88 ± 6.73) ml, and hospital stay was (6.63 ± 0.77) d, which was significantly better than the PLIF group, and the difference was statistically significant. And the postoperative VAS and ODI scores, intervertebral space height, and lower lumbar anterior convexity angle scores were significantly improved, and the differences were statistically significant when compared with the PLIF group. Overall, there were also fewer postoperative complications and high effectiveness, and satisfactory recent clinical efficacy was obtained. Its main advantages are as follows:
(1) The OLIF procedure works in the gap between the psoas major muscle and the abdominal aorta, and finally reaches the target disc directly, with the operating interval in the anterior lumbar spinal canal, which can effectively reduce the vascular nerve injury in the abdominal cavity and around the spinal canal, and significantly reduce the operation time, bleeding and complications.
(2) The OLIF procedure and the Wiltse approach preserve the ligamentous complex and posterior column structure to a greater extent, effectively avoiding excessive stripping and injury to the paravertebral muscles, which not only maintains the structural stability and stress environment of the lumbar spine, but also reduces the degree of postoperative low back pain. No direct spinal decompression is required, with little trauma and quick recovery.
(3) The implanted intervertebral fusion can have a larger area than the PLIF procedure, and the intervertebral fusion comes with an anterior or lateral convexity angle, which can restore the intervertebral space height and indirect spinal canal decompression while reconstructing the coronal sagittal balance. It can improve the stability of the anterior and middle columns of the lumbar spine and assume the main axial pressure.
Indications For Olif Combined With Wiltse Approach Pedicle Screw Fixation For Single-level Dls
OLIF combined with Wiltse approach pedicle screw fixation for single-level DLS has significant advantages over OLIF and PLIF alone, but the indications for the procedure still need to be controlled. (1) no further posterior decompression is required; (2) mild lumbar degenerative slippage with Meyerding grade I; (3) no disc prolapse, no severe ligamentum flavum hyperplasia or calcification, and no severe spinal stenosis in the target segment. (4) persistent low back pain and other symptoms exist, conservative treatment > 3 months or more is ineffective and significantly affects life; (5) good spinal stability, no serious lateral protrusion or kyphosis, no serious osteoporosis, and the patient can accept this operation; (6) no history of lumbar interbody fusion surgery in the target segment, no non-lumbar degenerative pathology such as septic disc infection; (7) necessary and suitable for Wiltse approach patients with pedicle screw fixation.
Surgical Considerations For Olif Combined With Wiltse Approach Pedicle Screw Fixation For Single-level Dls
Rational surgical planning and operation are crucial, and to Abe et al. found in a multicenter retrospective study that most of the complications of OLIF were operationally related, and the complication rate was 48.3%, so we need to keep the following surgical considerations in mind:
(1) Postural exchange: Since the OLIF procedure requires right lateral recumbency and the Wiltse approach requires a prone position for pedicle screw fixation, it is necessary to pay attention to the replacement of lateral block and axillary pillow during the articulation and position rotation, and to prevent wound contamination and aseptic operation during this process.
(2) Bleeding control: preoperative lumbar MRI examination is performed to assess the anatomical position of the abdominal vena cava and the natural gap between the vessels, and to exclude vascular variant alignment. Intravenous tranexamic acid can be administered half an hour before surgery, thus reducing intraoperative bleeding. Familiarity with the anatomical position avoids injury to the main arteries such as the common iliac and iliolumbar and complete hemostasis, and autologous blood transfusion can be used.
(3) Surgical access and traction: accurate body surface positioning of the OLIF surgical incision is required before surgery, the access cannot be too vertical or tilted, and excessive traction cannot be used to stimulate the psoas major muscle to avoid postoperative thigh paresthesias and reduced strength of the psoas major muscle.
(4) Avoid ureteral injury: intraoperative blunt separation of tissues needs to be cautious, if the intraoperative urinary fluid outflow is seen, or postoperative appearances such as abdominal pain, abdominal distension, hematuria, vomiting, etc. need to be promptly addressed and remedied.
(5) Avoid nerve injury: intraoperative use of somatosensory evoked potential detection can help reduce the chance of intraoperative nerve injury and identify patients who are prone to induce neurological injury.
(6) Fusion device sedimentation vigilance: intraoperative scraping of cartilage endplates should avoid bony endplate injury. For those with more lax bone quality, a wider intervertebral fusion should be selected and the fusion should be implanted as parallel to the vertebral space as possible.
(7) Posterior pedicle screw treatment: avoid excessive deviation to the lateral side of the transverse process during pedicle screw implantation or multiple adjustments of the nail placement channel resulting in poor stability. When the bone is lax, the nail channel can be reinforced with polymethylmethacrylate to increase screw stability.