Spondylosis is regarded as stress fracture and occurs in about 5%of young population. The most common level of occurrence is the L5 level due to the unique shearing force applied at L5-S1 area. The main symptom of spondylosis and spondylolisthesis are low back pain, leg pain, and numbness.

If conservative treatment proves ineffective surgical treatment is recommended. Transforaminal Lumbar Interbody Fusion, TLIF is an effective and established technique but the non-union rate of this procedure is relatively higher at the L5-S1 level. Furthermore TLIF is difficult to create a decreased lordosis compared to Oblique Lumbar Interbody Fusion, ORIF or Anterior Lumbar Interbody Fusion, ALIF.

Interior decompression such as ALIF or ORIF are currently common method for treating lumbar stenosis. However, a compressional method cause a large amount of muscle damage. OLIF at 5-S1 level, OLIF-51 was first reported in 2017.

Posterior Ligament Augmentation is usually necessary to ensure solid fusion but the conventional OLIF technique use C-arm and the patient position is changed from lateral to prone. To overcome these problems we propose a novel technique of C-arm free simultaneous OLIF-51 implanting pedicle screw fixation in a single lateral position. In this video, we introduce a case of a 75 year old woman with symptomatic L5 spondylolisthesis.

This study was approved by the Essex committee at Okayama Rosai Hospital. This is a protocol of C-arm free simultaneous OLIF-51 and percutaneous pedicle screw fixation. Check the preoperative image.

Functional radiograms helps us to evaluate spinal instability. MRI give us the information of neural dish. CT scan are important to check boney structure.

Vascular window which is made of common iliac vessels at L5-S1 disk level is clearly demonstrated by CT MRI fusion image. This procedure is performed under general anesthesia. Operation table should be full carbon table to perform CT scan by O-arm.

This is Pro axis which is adjustable full carbon table. Patient is pressed in light lateral decubitus position with tape. If possible the neuro monitoring is recommended to prevent neurological complication during OLIF.

We use NIM neuro monitoring system. Navigation reference frame is pressed percutaneously into sacroiliac joint. Then O-arm is set and intraoperative CT scan is performed.

4 centimeter upper skin incision along the peri is made then alongside with skin incision the abdominal muscles were divided and dissected. After exposing pro left common iliac vessels are identified and left gradualy by a blue self retaining retractor with elimination. The navigated probe is used to check the L5-S1 disk space.

A green grade is to retract right side common iliac vessels. A light blue grade is to retract bifurcation of common iliac vessels. Now you can see L5-S1 disc very clearly.

The annulus is cut with a knife and discectomy is performed using pituitary forceps. With the navigated pointer you can confirm the anatomy in a 3D way without C-arm. This is ligature.

This is a navigated combo tool to make enterprise smooth. This is navigated shaver. This is navigated trial.

For OLIF-51 cage size is from 10 to 16 millimeter and robotic cage angle are 8, 12, 18 degrees. A cage is inserted with a mallet. After the cage is inserted a supplemental screw is inserted.

Another surgeon performs percutaneous pedicle screw fixation simultaneously. These are postoperative radiograms. There were 14 cases of this new technique.

To compare with 40 cases of TLIF-51 preoperative L5-S1 angle of OLIF-51 and TLIF-51 were 11.4 degrees and 10.1 degrees respectively. These were not significant difference. However, post operative L5-S1 angle of OLIF-51 and TLIF-51 were 21.3 degrees and 12 one point degrees respectively.

These result were statistically different. Also postoperative L5-S1 disk height of OLIF-51 group was higher than that of TLIF-51 group. Critical steps for our method.

First, preoperatively preparation of the location of common iliac vessels is very important because the vascular window, less than 20 millimeter lead presents a contraindication for OLIF-51.Second. The difference frame pin should be firmly inserted in the left SI joint percutaneously. If the difference frame is moved the accuracy of this procedure, wasn't risking screw or cage malposition, Third, navigated instrument including a pointer, pedicle probe, shaver should be used effectively As an alternative a C-arm technique is also available for this simultaneous method and certain limitation to this technique must be considered.

Relatively expensive equipment, such as O-arm and navigation system is necessary. With a steep learning curve for this technique. Further studies in the form of case series are necessary to ensure this technique remains effective for managing ischemic spondylolisthesis.

In summary C-arm free OLIF-51 and simultaneous percutaneous pedicle screw fixation performed in a single lateral position under navigation guidance. This novel technique reduces surgical time and radiation hazards to surgeon and operating staff. Thank you for your attention.