Minimally invasive multiple-rod constructs with robotics planning in adult spinal deformity surgery: a case series

Multiple-rod constructs (MRCs) are often used in deformity correction for increased stability and rigidity. There are currently no reports showing minimally invasive placement of MRCs in adult deformity surgery and its technical feasibility through preoperative software planning. Data were collected retrospectively from medical records of six consecutive patients who underwent minimally invasive MRCs with robotics planning by a single surgeon at an academic center between March–August 2020. A total of six patients (4 females, mean age 69.7 years) underwent minimally invasive long-segment (6 +) posterior fixation with multiple rods (3 +) using the Mazor X Stealth Edition robotics platform. Average follow-up was 14.3 months. All patients underwent oblique lumbar interbody fusion (OLIF) as a first stage, followed by second stage posterior fixation in the same day. The mean number of levels posteriorly instrumented was 8.8. One patient underwent 3 rod fixation (1 iliac, 2 S2AI) and 5 patients underwent quad rod fixation (2 iliac, 2 S2AI). The mean time to secure all rods was 8 min 36 s. Mean improvement in spinopelvic parameters was -4.9 cm sagittal vertical axis, 18.0° lumbar lordosis, and -10.7° pelvic tilt with an average pelvic incidence of 62.5°. Estimated blood loss (EBL) was 100–250 cc with no blood transfusions, and all but one patient ambulated on postoperative day 1 or 2. Spinal robotics brings us into a new era of minimally invasive construct design. To our knowledge, this is the first description of the technical feasibility of MRCs in minimally invasive adult spinal deformity surgery.