Novel Merging of CT and MRI to Allow for Safe Navigation into Kambin's Triangle for Percutaneous Lumbar Interbody Fusion—Initial Case Series Investigating Safety and Efficacy

Abstract

BACKGROUND: For percutaneous lumbar fusion (percLIF), magnetic resonance imaging and computed tomography are critical to defining surgical corridors. Currently, these scans are performed separately, and surgeons then use fluoroscopy or neuromonitoring to guide instruments through Kambin's triangle. However, anatomic variations and intraoperative positional changes are possible, meaning that safely accessing Kambin's triangle remains a challenge because nerveroot visualization without endoscopes has not been thoroughly described. OBJECTIVE: To overcome the known challenges of percLIF and reduce the likelihood of iatrogenic injuries by showing real-time locations of neural and bony anatomy. METHODS: The authors demonstrate an intraoperative navigational platform that applies nerve root segmentation and image fusion to assist with percLIF. Five patients from a single institution were included. RESULTS: Of the 5 patients, the mean age was 71 ± 8 years and 3 patients (60%) were female. One patient had general anesthesia while the remaining 4 patients underwent awake surgery with spinal anesthesia. The mean area for the L4-L5 Kambin's triangle was 76.1 ± 14.5 mm 2 . A case example is shown where the side of approach was based on the fact that Kambin's triangle was larger on one side compared with the other. The mean operative time was 170 ± 17 minutes, the mean blood loss was 32 ± 16 mL, and the mean hospital length of stay was 19.6 ± 8.3 hours. No patients developed postoperative complications. CONCLUSION: This case series demonstrates the successful and safe application of nerve segmentation using magnetic resonance imaging/computed tomography fusion to perform percLIF and provide positive patient outcomes.

Two-Year Clinical and Radiographic Outcomes for Percutaneous Lumbar Interbody Fusion With an Expandable Titanium Cage Through Kambin’s Triangle Without Facetectomy

“…51 However, they also reported that the rail-road technique of placing a tapered dilator followed by a snugly fitting cannula does not increase the frequency of ENR injury as previously thought in the literature. 52,53 Additionally, the authors mentioned that ENR visualization was often difficult given that the nerve was not always a perfect oval shape. Without accurately visualizing the nerve root, truly measuring the maximum safe area of Kambin's bony triangle is limited.…”

Evolution of the Transforaminal Lumbar Interbody Fusion (TLIF): From Open to Percutaneous to Patient-Specific

“…Further, the insertion of these devices requires less nerve root retraction and potentially reduces postoperative complications such as cage subsidence [21]. Similarly, the MIS-TLIF platform has become a cornerstone for integrating cutting-edge imaging technologies such as robotic assistance, 3D neurosegmentation, and augmented reality [24][25][26]. These advancements have solidified the role of the MIS-TLIF as a fundamental framework for ongoing research and development in spine surgery.…”

“…(3) identifying potential anatomic anomalies like conjoined nerve roots; and (4) comparing the areas of each safe corridor to reduce the risk of iatrogenic injury. Tabarestani et al showcased the first practical application of this technology in a small case series where Kambin's Triangle volumes were measured for all patients bilaterally at the level of operation [26]. By comparing contralateral areas, the surgeon was able to decide on the 'ideal' laterality of their approach, entering the largest, safest triangle with the greatest distance from the exiting nerve root.…”

“…Due to his bilateral facet arthropathy, the team decided to segment the patient's spine to obtain better visualization of both Kambin's Triangles to access the disc space safely. The segmentation was carried out using high-resolution T2 MRI-SPACE sequences in BrainLab (Munich, Germany), as has been previously described in the literature [26]. Based on measurements of both the maximum permissible cannula diameter and safe area, the right percLIF approach was chosen, given that it comprised the largest dimensions (9 mm and 101 mm 2 , respectively).…”

“…Given that her previous L4-5 facet injections provided temporary relief, she was offered a TLIF to correct her misalignment. Due to the nature of her severe facet arthrosis, with widening of the left facet joint and narrowing of the lateral recesses bilaterally, the team segmented the patient's spine to better visualize potential corridors for safe disc space access [26]. Based on measurements of both the maximum permissible cannula diameters and safe working areas, the left TF-LIF approach was chosen, given its larger dimensions (10.2 mm and 161.1 mm 2 , respectively) compared to the right TF-LIF trajectory and either percLIF approach.…”