Corner Osteotomy As the More Advanced Approach to Deformity Correction in Adult Spinal Deformity: A Retrospective Comparative Study Between Two Osteotomy Techniques

Abstract

Study design: A retrospective study.

Objective: To investigate the usefulness of corner osteotomy (CO) in patients with adult spinal deformity (ASD) by comparing it with pedicle subtraction osteotomy (PSO) for lordosis correction.

Summary of background data: PSO remains a valuable procedure for patients with ASD, but it has a limit to obtaining correction angles exceeding 45° in patients with a large pelvic incidence or with previous spinal fusion surgeries. Theoretically, CO can exceed the limitation of PSO and can achieve a wide range of correction angles. However, no study has analyzed the clinical data and usefulness of CO.

Methods: This study included 115 patients (mean age: 71.1 yr, mean follow-up period: 78.9 mo) with ASD who underwent deformity correction using PSO or CO. Comparative analysis was performed on spinopelvic parameters including segmental angle (SA) around the osteotomy site, and clinical and surgical assessment between the PSO and corner groups.

Results: In the corner group, the postoperative SA (35° vs. -39.3°, P =0.004) and the degree of SA correction (34.8° vs. 39.7°, P =0.004) were greater, and a broader range of SA correction was also possible (18-51° vs. 18-61°). Although the operative time was longer in the corner group (316.8 vs. 342.3 min, P =0.014), the estimated blood loss (EBL) was lower (2841.3 vs. 2465.4 mL, P =0.032). There was no difference in major complication rates, but the frequency of rod fracture (RF) was lower in the corner group (36/27 vs. 1/51, P <0.05).

Conclusions: CO showed a greater SA correction and achieved a broader range of SA correction angles than PSO, with no difference in the incidence of major complications. In addition, the EBL and the frequency of RF were lower. Based on these results, we expect that CO can serve as a promising surgical alternative to PSO for spinal deformity correction among patients with ASD.

Keywords: adult spinal deformity; corner osteotomy; lumbar lordosis correction; pedicle subtraction osteotomy; rod fracture.

Figure 1

Schematic comparison of PSO and corner osteotomy.

Figure 2

Schematics for the various correction angles with different hinge points in corner osteotomy.

Figure 3

Ranges of the postoperative segmental angle and the degree of segmental angle correction in the PSO group and the corner group.

Figure 4

This 66-year-old female presented to us with degenerative sagittal imbalance with PLIF on L3-5 state (SVA +241 mm, TK 15°, LL 2°, PI 74°, PT 51°, SS 23°). The patient underwent T10-S1 posterior instrumentation with pedicle subtraction osteotomy on L2 with applying accessory rods. The postoperative radiograph showed an optimal sagittal balance (SVA 7 mm, TK 40°, LL −70°, PT 32°, SS 42°), and CT and radiograph at postoperative 3 months show the progression of bony union with bone-bridge formation. At postoperative 3 years, sagittal alignment was well-maintained without rod fracture (SVA −11 mm, TK 45°, LL −77°, PT 31°, SS 43°). Arrows indicate the C7 plumb line.

Figure 5

Early bone fusion effect with bone-to-bone contact in corner osteotomy.

Figure 6

This 66-year-old female presented to us with degenerative sagittal imbalance with PLIF on L4-S1 state (SVA +232 mm, TK 0°, LL 8°, PI 64°, PT 39°, SS 25°). The patient underwent T10-S1 posterior instrumentation with corner osteotomy on L3 with applying accessory rod. The postoperative radiograph showed an optimal sagittal balance (SVA −9 mm, TK 21°, LL −73°, PT 15°, SS 49°), and CT and radiograph at postoperative 3 months showed bony union with bone-bridge formation. At postoperative 3 years, sagittal alignment was well-maintained without rod fracture (SVA −1 mm, TK 50°, LL −69°, PT 16°, SS 48°). Arrows indicate the C7 plumb line.