Successful fusion versus pseudarthrosis after spinal instrumentation: a comprehensive imaging review.

PURPOSE: Following spinal instrumentation and fusion, differentiating between successful arthrodesis and pseudoarthrosis on imaging can be challenging. Interpretation of such examinations requires understanding both the expected evolution of postoperative findings and the subtle indicators of pseudoarthrosis across multiple imaging modalities. Due to this level of intricacy, many clinicians lack familiarity with the subject beyond the more rudimentary concepts. METHODS: This review provides an in-depth overview of the imaging of the post-operative spine, with particular emphasis on differentiating between pseudoarthrosis and arthrodesis. RESULTS: A comprehensive overview of imaging of the post-operative spine is given, including the most common imaging modalities utilized, the expected post-operative findings, imaging findings in pseudoarthrosis, and imaging definitions of fusion. CONCLUSION: Differentiating between pseudoarthrosis and arthrodesis in the postoperative spine is complex, and requires a robust understanding of various findings across many different modalities.

Ten-year follow-up of Lenke 5 curves treated with spinal fusion.

INTRODUCTION: Patients with surgically treated Lenke 5 curves require at least partial fusion of the lumbar spine. The implications of lumbar fusion remain unknown as long-term follow-up is sparse. METHODS: A retrospective review of a prospectively collected registry of patients with Lenke 5 curves treated with spinal fusion was performed. Clinical and radiographic outcomes as well as SRS-22 scores were collected at 2- and 10-year follow-up. RESULTS: 54 of 247 available patients met all inclusion criteria [26 treated with posterior spinal fusion (PSF) and 28 with anterior spinal fusion (ASF)]. Preoperative lumbar curve magnitude was 45.1 ± 8.4° and corrected to 14.0 ± 7.2° (p < 0.001). A 3.3 ± 7.3° increase in curve size was noted at final follow-up (p < 0.008) with 20.3% of patients having a loss of correction (LOC)of 10° or more. Thoracic curve correction and kyphosis were stable at 10-year follow-up. End vertebrae angulation improved from 11.2 ± 23.2° to 0.96 ± 6.4° (p = 0.004) and translation improved from 2.5 ± 2.9 to 0.92 ± 1.5 cm (p = 0.008) with no LOC. Disc wedging below the lower instrumented vertebrae increased from 0.3 ± 4.9° to 2.8 ± 4.4° (p < 0.001) with no change at 10 years. SRS-22 self-image and satisfaction improved from post-operative to final follow-up. No patient required a second operation. CONCLUSIONS: Both ASF and PSF showed durable results at 10-year follow-up with no obvious difference between approaches. 20% of patients had a LOC > 10°; this did not correlate with pain or need for revision surgery. Disc wedging was stable. Selection of LIV did not correlate with pain scores. LEVEL OF EVIDENCE: Level III.