Predictors of the need for rib resection in minimally invasive retroperitoneal approach for oblique lateral interbody fusion at upper lumbar spine (L1-2 and L2-3)

Radiological Outcomes and Approach-Related Complications in Oblique Lateral Interbody Fusion at the Upper Lumbar Level

Background/Objectives: Despite recent advances in minimally invasive extrapleural lateral approaches, oblique lateral interbody fusion (OLIF) at the upper lumbar level is often difficult and limited to optimal reconstruction. We aimed to compare the radiological outcomes and approach-related complications of OLIF between the upper (L1-2 or L2-3) and lower (L3-4 or L4-5) levels. Methods: This study is a retrospective review of OLIF in the upper (n = 63) and lower (n = 60) lumbar level groups. Radiological parameters included the anterior/posterior disc height, coronal/sagittal disc angle, cage position, cage subsidence, and fusion rate at a postoperative 1-year follow-up. Approach-related complications including pleural/peritoneal lacerations, neurovascular injury, and other organ injuries were examined. Results: The baseline radiological parameters were similar between the two groups (all p > 0.05). At 1-year postoperatively, the anterior disc height (ADH) was significantly greater in the lower-level group (p = 0.031), while no significant differences were observed in the posterior disc height, coronal/sagittal disc angle, cage anterior position, or cage subsidence rate (all p > 0.05). The fusion rates were 97.9% and 95.0% at the upper and lower lumbar levels, respectively (p = 0.146). During OLIF at the upper lumbar level, chest tube insertion due to pleural laceration was observed in 11 (17.5%) cases. One case (1.2%) of segmental artery injury and two cases (3.2%) of pseudo-hernia were attributed to iliohypogastric nerve injury. Conclusions: Although the extrapleural approach in OLIF at the upper lumbar level is often limited, the radiological outcomes were comparable to those of OLIF at the lower lumbar level.

The Minimally Invasive Intercostal Subdiaphragmatic Access without Rib Resection for Lateral Lumbar Interbody Fusion at L1/2: Surgical Techniques and Cases Illustration

OBJECTIVE

The minimally invasive (MI) lateral approach to the thoracolumbar junction for treating various spinal pathologies is quite challenging for spine surgeons due to this region's unfamiliar and complex anatomical structures. In addition, controversy still exists regarding approach selection, the need for rib resection, and diaphragm manipulation.

METHODS

We present the senior author (N. A.) technique of an intercostal subdiaphragmatic retroperitoneal approach without rib resection for the lateral lumbar interbody fusion (LLIF) procedure at L1/2 in patients who underwent multilevel LLIF from L1/2 to L5/S1. Also, we demonstrate a similar subdiaphragmatic retroperitoneal access technique, using a single skin incision with 2 fascial approaches for performing the single-level LLIF L1/2 in a cadaver.

RESULTS

The staged procedures for multilevel LLIF L1-S1 were completed without any complications. The patient's symptoms significantly improved after the operations. Improvements to the radiographic parameters were also noted.

CONCLUSIONS

Intercostal subdiaphragmatic retroperitoneal access without rib resection is an alternative MI lateral approach to the upper lumbar spine. These reproducible techniques could help surgeons access the L1/2 disc level without unnecessary rib resection. Surgeons can use this technique for performing a single-level lateral approach at L1/2 or incorporate this MI technique with a standard lateral approach to the lower lumbar spine for performing sequential multilevel lateral fusion for patients diagnosed with adult spinal deformity.

Anterior Lumbar Interbody Fusion Versus Oblique Lumbar Interbody Fusion Versus Lateral Lumbar Interbody Fusion: Which One in Which Patient?

Anterolateral approaches to the lumbar spine provide direct access to the disc space. These techniques facilitate thorough discectomy, which is essential for successful arthrodesis. They improve segmental lordosis without osteotomy and indirectly decompress neural elements in carefully selected patients. Benefits include shorter operative times, reduced blood loss, and rapid postoperative mobilization compared to posterior approaches. Each technique has specific advantages and limitations, thus none is inherently superior to another. Detailed knowledge of these techniques is essential for modern spine surgeon to provide personalized operative plan for each patient.

Mini-Open Intercostal Retroperitoneal Approach for Upper Lumbar Spine Lateral Interbody Fusion

OBJECTIVE

Conventional oblique lumbar interbody fusion (OLIF) approach is possible from the L2/3 to L4/5 levels. However, obstruction of the lower ribs (10th-12th) makes it difficult to maintain disc parallel maneuvers or orthogonal maneuvers. To overcome these limitations, we proposed an intercostal retroperitoneal (ICRP) approach to access the upper lumbar spine. This method does not expose the parietal pleura or require rib resection and employs a small incision.

METHODS

We enrolled patients who underwent a lateral interbody procedure on the upper lumbar spine (L1/2/3). We compared the incidence of endplate injury between conventional OLIF and ICRP approaches. In addition, by measuring the rib line, the difference in endplate injury according to rib location and approach was analyzed. We also analyzed the previous period (2018-2021) and the year 2022, when the ICRP has been actively applied.

RESULTS

A total of 121 patients underwent lateral interbody fusion to the upper lumbar spine (OLIF approach, 99 patients; ICRP approach, 22 patients). Endplate injuries occurred in 34 of 99 (34.3%) and 2 of 22 patients (9.1%) during the conventional and ICRP approaches, respectively (p = 0.037; odds ratio, 5.23). When the rib line was located at the L2/3 disc or L3 body, the endplate injury rate was 52.6% (20 of 38) for the OLIF approach but 15.4% (2 of 13) for the ICRP approach. Since 2022, the proportion of OLIF including L1/2/3 levels has increased 2.9-fold.

CONCLUSION

The ICRP approach is effective in reducing the incidence of endplate injury in patients with a relatively lower rib line, without pleural exposure or rib resection.