Lumbar endplate inflammation is a common cause of pain in the lumbar spine and leg. It is mainly caused by prior injuries to the vertebral body, ischemic lesions of the vertebral endplate or degenerative lesions of the vertebral body. Because it has an unclear specific pathogenesis, it is often missed entirely or misdiagnosed[8, 9]. The incidence of lumbar endritis has increased recently because people are more sedentary. Onset also occurs at a younger age. Its clinical symptoms are waist pain, radiation of pain to the lower limbs, numbness, weakness and intermittent claudication resulting in long-term chronic pain that has a serious impact on people’s work lives and activities of daily living. Clinically, some patients with long-term lumbar and leg pain and no obvious curative effect after conservative treatment choose surgical intervention. Surgical treatment commonly involves lumbar intervertebral fusion, the most common being posterior lumbar vertebral fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF). Intervertebral fusion surgery can improve stability of the vertebral body and can alleviate some clinical symptoms. However, because PLIF and TLIF require intraoperative separation of paravertebral muscles, partial excision of the lamina, facet joint and posterior ligament complex, as well as traction on nerve roots, it may cause postoperative chronic low back pain[10, 11]. Therefore, there is a need to find both minimally invasive as well as safe and effective surgical methods in clinical practice.
In recent years, OLIF surgery has been favored by physicians because it has advantages such as a short operation time, less intraoperative blood loss and quick postoperative recovery. Moreover, since OLIF began to be applied in clinical practice, more and more studies have been conducted on the treatment of related diseases by OLIF. The minimally invasive technology of OLIF has continued to mature, making surgery easier and safer[6]. Compared with other approaches, OLIF has its own unique advantages.
OLIF uses a retroperitoneal approach to reach the intervertebral space between the abdominal aorta and the anterior edge of the psoas major muscle. the anatomy is simple, and it is not easy to damage blood vessels and muscles, which greatly shortens the operation time and reduces the trauma during the operation. there is often little bleeding during the operation and a quick recovery after operation. In this study, the operation time of 36 patients was 98.7 ± 16.8min (60-130min), and the intraoperative blood loss was 50.2 ± 10.7ml (30-120ml), which was significantly lower than that of traditional surgery[12, 13]. All patients could wear braces to move under the ground on the second day after operation, and there was no poor wound healing after operation.
In OLIF operation, intervertebral space was treated and fusion cage was placed through the space between abdominal aorta and anterior edge of psoas major muscle, without going through spinal canal or pulling the nerve in spinal canal, and there was no need to split psoas major muscle, so iatrogenic lumbar plexus injury and postoperative chronic low back pain caused by muscle injury were avoided[5, 14]. Of the 36 patients in this study, only 1 patient developed weakness and numbness in the right thigh, and the symptoms were relieved after rest. This is mainly due to the well-developed psoas major muscle, which destroys the nerves and muscle tissue in the psoas major muscle when entering the intervertebral space through the abdominal aorta and the anterior edge of the psoas major muscle. Therefore, familiar anatomy, correct path, clear vision, careful operation, especially in the separation of psoas major muscle and vascular sheath, avoiding electrocoagulation or electroknife cutting can minimize nerve injury.
Compared with posterolateral fusion, OLIF does not cause damage to the lumbar posterior ligamentous complex or facets, and uses a wider fusion apparatus, resulting in a larger fusion area and better immediate stability at the fused segment. Bone fusion was observed in all patients at the final follow-up, and no loosening of the internal fixation of the implants was observed.
With the development of clinical OLIF surgery, there also have been reports of related complications such as fusion organ sinking, fusion organ displacement, urinary system injury, and injury of large and small blood vessels. Woods et al. [15] conducted a retrospective study of 137 patients who underwent OLIF surgery. In this cohort, the complication rate was 11.7%. The most common complications were depression (4.4%), postoperative intestinal obstruction (2.9%), and vascular injury (2.9%). None of these complications occurred in this study. To reduce the complications of OLIF surgery, clinicians should select the appropriate size of the fusion device, familiarize themselves with the local anatomical structure of the abdomen, improve preoperative vascular and nerve assessment, and reduce traction on the psoas major muscle during surgery.
In conclusion, the recent clinical effect of OLIF in the treatment of lumbar endritis is satisfactory. It can achieve indirect decompression and improve intervertebral fusion area and rate. This study had a small sample size with a short follow-up time and was not a randomized controlled trial so it should be verified by a randomized controlled clinical trial with a larger sample size. In addition, the OLIF technique requires familiarity with the surgical approach, abdominal organ anatomy and neurovascular anatomy[14, 16]. Minimally invasive surgeries such as this one will continue to improve and result in more rapid recovery and better patient satisfaction.