Lateral versus prone robot-assisted percutaneous pedicle screw placement: a CT-based comparative assessment of accuracy

J Neurosurg Spine 37:112–120, 2022

Single-position lateral lumbar interbody fusion (SP-LLIF) has recently gained significant popularity due to increased operative efficiency, but it remains technically challenging. Robot-assisted percutaneous pedicle screw (RAPPS) placement can facilitate screw placement in the lateral position. The authors have reported their initial experience with SP-LLIF with RA-PPS placement in the lateral position, and they have compared this accuracy with that of RA-PPS placement in the prone position.

METHODS The authors reviewed prospectively collected data from their first 100 lateral-position RA-PPSs. The authors graded screw accuracy on CT and compared it to the accuracy of all prone-position RA-PPS procedures during the same time period. The authors analyzed the effect of several demographic and perioperative metrics, as a whole and specifically for lateral-position RA-PPS placement.

RESULTS The authors placed 99 lateral-position RA-PPSs by using the ExcelsiusGPS robotic platform in the first 18 consecutive patients who underwent SP-LLIF with postoperative CT imaging; these patients were compared with 346 prone-position RA-PPSs that were placed in the first consecutive 64 patients during the same time period. All screws were placed at L1 to S1. Overall, the lateral group had 14 breaches (14.1%) and the prone group had 25 breaches (7.2%) (p = 0.032). The lateral group had 5 breaches (5.1%) greater than 2 mm (grade C or worse), and the prone group had 4 (1.2%) (p = 0.015). The operative level had an effect on the breach rate, with breach rates (grade C or worse) of 7.1% at L3 and 2.8% at L4. Most breaches were grade B (< 2 mm) and lateral, and no breach had clinical sequelae or required revision. Within the lateral group, multivariate regression analysis demonstrated that BMI and number of levels affected accuracy, but the side that was positioned up or down did not.

CONCLUSIONS RA-PPSs can improve the feasibility of SP-LLIF. Spine surgeons should be cautious and selective with this technique owing to decreased accuracy in the lateral position, particularly in obese patients. Further studies should compare SP-LLIF techniques performed while the patient is in the prone and lateral positions.

A Staged Protocol for Circumferential Minimally Invasive Surgical Correction of Adult Spinal Deformity

Neurosurgery 81:733–739, 2017

Minimally invasive surgery (MIS) techniques used for management of adult spinal deformity (ASD) aim to decrease the physiological demand on patients and minimize postoperative complications. A circumferential MIS (cMIS) protocol offers the potential to maximize this advantage over standard open approaches, through the concurrent use of multiple MIS techniques.

OBJECTIVE: To demonstrate through a case example the execution of a cMIS protocol for management of an ASD patient with severe deformity.

METHODS: Thorough preoperative assessment, surgical planning, and medical optimization were completed. Deformity correction was performed over 2 stages. During the first stage, interbody fusion was performed via an oblique lateral approach at all levels of the lumbar spine intended to be included in the final construct. The patient was kept as an inpatient and mobilized postoperatively. They were then re-imaged with standing films. The second stage occurred after 3 d and involved percutaneous instrumentation of all levels. Posterior fusion of the thoracic levels was achieved through decortication of pars and facets. These areas were accessed through the intermuscular plane established by the percutaneous screws. The patient was mobilizing on their first postoperative day.

RESULTS: In a 66-yr-old female with severe sagittal imbalance and debilitating back pain, effective use of this cMIS protocol allowed for correction of the Cobb angle from 52◦ to 4◦ correction of spinopelvic parameters and 13 cm of sagittal vertical axis improvement. No complications were identified by 2 yr postoperative.

CONCLUSION: As a systematization of multiple MIS techniques combined, in a specific and staged manner, this cMIS protocol could provide a safe and effective approach to the management of ASD.