Optimizing Minimally Invasive Spine Surgery: A Fully 3D CT O-Arm Navigated Workflow in MIS TLIF

Our study assesses the outcome of fully navigated CT assisted MIS TLIF in single level regenerative lumbar disorder. Switching from conventional real-time imaging to XR.Integrating the workflow of decompression fixation and imaging in a single procedure is a challenge. To begin, place the patient under general anesthesia and position them prone on a padded radiolucent spinal table.

Secure the patient with chest and pelvic bolsters and non constrictive cross body straps to prevent movement. Confirm that there are no pressure points or abdominal compression. Prepare and drape the surgical field using the standard aseptic technique.

Set up the 3D computed tomography, imaging system, navigation workstation, and high definition optical visualization system. Adjust the loop magnification to 2.5 times or the exoscope or microscope magnification to five to 10 times. Attach the dynamic reference frame proximally at the lower thoracic region using non-absorbable suture material and check for rigid anchorage of the frame.

Acquire a baseline computed tomography spin using the standard lumbar protocol with 120 kilovolts peak, 200 milliamp your seconds, a 512 by by 512 matrix and one millimeter slice thickness. Register the acquired 3D image dataset to the navigation system. Use one to two anatomical points to interpolate and verify that the error is less than or equal to one millimeter before proceeding.

Using navigation guidance and the pedicle access kit needle overlay on the screen mark paramedian skin incisions four to six centimeters lateral to the midline at the surgical level. Target the junction of the facet and transverse process with as lateral and entry projection as possible. Using a number 22 scalpel blade.

Incise the skin and underlying fascia longitudinally to a length of approximately four centimeters. Under navigation, advance a 13 gauge 15 millimeter pedicle access kit needle to the junction of the facet and transverse process. Enter the center of the index pedicle in both axial and sagittal planes.

While ensuring a safe trajectory and enhancing convergence continuously check intraoperative navigation screens to confirm that the needle tip remains within the cortical bone. In cases of smaller pedicles except a lateral entry with medial convergence and an extra particular trajectory, remove the stylet and railroad a one millimeter nitinol steel guide wire through the sheath of the pedicle access kit needle into the vertebral body confirming placement with tactile feedback and resistance of cancellous bone. Once secured, remove the pedicle access kit needle sheath place, and secure four guide pins bilaterally into the pedicles of the segment.

Then bend and tether them to the drapes using Alice forceps to keep them away from the central operative field For decompression, make a separate medial facial incision through the same skin incision under navigation guidance to determine the site, usually two to three centimeters from the spinous process. Place a guide wire onto the index facet for lateral recess stenosis. Unilateral decompression cases sequentially dilate the paraspinal muscle layers with 12, 16 and 20 millimeter dilators over the guide wire and dock a 22 millimeter tubular quadrant retractor over the dilators onto the facet.

Now secure the quadrant retractor to the table mounted arm to achieve targeted lateral recess stenosis decompression, or over the top decompression. Perform the steps shown under magnification and illumination using a sized cage on a navigated cage holder impactor place the selected polyether ether ketone or titanium interbody cage into the prepared interbody space under navigation with a safe trajectory, remove the tubular retractor assembly from the surgical site. Then using navigation guidance, place cannulated pedicle screws bilaterally over the guide wires based on appropriate sizing.

Confirm tactile feedback for proper screw purchase, and remove the guide wire as the screws cross the pedicle. Using a calibrated rod caliber determine the required rod length interoperatively by aligning it between the screw tulip heads through percutaneous extensions. Next, introduce the pre contoured lordotic measured rod percutaneously using a rod inserter tool, verify proper engagement of the rod within each screw tulip using a rod position checker.

Perform sequential tightening of the set screws with a torque limiting driver under compression mode at eight Newton meters. Acquire a final 3D computed tomography spin to confirm hardware position, proper screw and cage placement and congruent implant alignment with the spinal midline. Irrigate the wound and achieve meticulous hemostasis.

Place a sub facial number 10 French drain at the medial intermuscular site. Finally, close the fascia with continuous 1-0 absorbable sutures. The subcutaneous tissue with interrupted 2-0 absorbable sutures and the subcuticular layer with 3-0 fast absorbing sutures.

In this series, 44 patients underwent fully navigated minimally invasive transforaminal lumbar interbody fusion. Most surgeries were performed at L4 to L5 level accounting for 72.72%The oswestry disability index improved from around 38.68 preoperatively to around 12.5 at final follow-up. And the numeric rating scale for back and leg pain improved from around 8.68 and 8.65 to 0.79 and 0.81 respectively.

The average operative time was around 124.14 minutes with a mean blood loss of around 100.45 milliliters. Screw accuracy was high with 6.8100000000000005%Gertzbein Grade 1 breaches, and 3.4%Modified Park Grade 1 facet violations. Our protocol addresses the entire MIS TLIF work protocol beyond just pedicle screws.

It provides continuous uninterrupted navigation for skin incision, port placement, screw, and cage placement, which is beyond the usual sequential navigation or partial navigation. The future research will focus on validating integrated navigation for large cohort of patients in multilevel spinal pathologists and different spinal pathologists.