Letter to the Editor: ‘Short-Term Comparison Between Unilateral Versus Bilateral Percutaneous Pedicle Screw Fixation in Short-Level Lateral Lumbar Interbody Fusion–A Prospective Randomized Study’ by Akihiko Hiyama et al

To the Editor,

We read with great interest the article by Akihiko Hiyama et al ¹ titled “Short-Term Comparison Between Unilateral vs Bilateral Percutaneous Pedicle Screw Fixation in Short-Level Lateral Lumbar Interbody Fusion”. The authors have admirably conducted a prospective randomized trial comparing unilateral (UPS) and bilateral percutaneous pedicle screw (BPS) fixation following lateral lumbar interbody fusion (LLIF). This approach addresses a critical gap in the literature as previous studies primarily focused on either technique without direct comparative trials.

However, there are some points that necessitate further consideration and discussion:

1. This study included patients of LDD (lumbar disc degenerative disease) who are more than 50 years of age without Osteoporosis while LDD is also frequently observed in younger population.^2,3 These young adults with LDD also have good Bone mineral density which would have supported Author’s aim to study the cohort of LDD without osteoporosis. Therefore, this would have further increased the sample size and helped to overcome one of the limitations.

2. As mentioned in the study, this trial was discontinued due to possible harm to the patients because of high incidence of cage subsidence in patients treated with unilateral percutaneous screw fixation. Even after this trial it remains inconclusive weather to do lateral lumbar fusion with UPS fixation or BPS fixation. In the conclusion, the authors have left it to the surgeon’s discretion to choose the patient for UPS fixation without recomending particular indications for UPS fixation.

3. UPS offers the advantage of reduced surgical invasiveness, aligning with the trend towards less disruptive procedures in spine surgery and shortens the duration of surgery. While comparing duration of surgery (OR Time) between UPS and BPS groups which showed statistically significant difference (P value - 0.029). It is noteworthy that when we perform a bilateral screw fixation patient needs to be repositioned, repainted and redraped which increases OR time in BPS group. Lumbar disc degeneration includes wide spectrum of diagnosis like spondylolisthesis in which unilateral fixation is inadequate and in this study distribution of diagnosis of patient in both cohort was not mentioned and surgeon was kept blinded.

Despite these challenges, this clinical trial has contributed significantly to the field of Spine surgeries and we are thankful for that.