Robot-assisted percutaneous screw placement combined with pelvic internal fixator for minimally invasive treatment of unstable pelvic ring fractures

Abstract

Purpose: The purpose of this study was to investigate the safety and efficacy of the combination of robot-assisted percutaneous screw placement and pelvic internal fixator (INFIX) for minimally invasive treatment of unstable anterior and posterior pelvic ring injuries.

Methods: From September 2016 to June 2017, twenty-four patients with unstable anterior and posterior pelvic ring injuries were treated with TiRobot-assisted percutaneous sacroiliac cannulated screw fixation on the posterior pelvic ring combined with robot-assisted pedicle screw placement in the anterior inferior iliac spine along with INFIX on the anterior pelvic ring. The results of the treatment, including surgery duration, fluoroscopy frequency, total drilling, amount of blood loss, fracture healing time, and postoperative functional outcomes were recorded and compared with another 21 similar patients who underwent conventional manual positioning surgery.

Results: The TiRobot group incurred significantly shorter duration of surgery; less fluoroscopy frequency, intraoperative bleeding, and total drilling than in the conventional group (P < 0.05). Postoperative radiological follow-up showed that all screws were in the safe area and no screw penetrated the cortex. All wounds healed by primary intention and no iatrogenic damage to the blood vessels, nerves, and organs occurred. Patients showed good tolerance to INFIX and reported no discomfort. The mean follow-up duration was 5.4 months; the fractures were all healed, no loss of reduction occurred, and the mean Majeed score at the last follow-up did not show any difference.

Conclusion: TiRobot-assisted percutaneous screw placement combined with INFIX for the anterior and posterior pelvic ring injuries is accurate, safe, less invasive, and shows satisfactory efficacy, suggesting it is a better method for minimally invasive treatment of unstable pelvic ring fractures.

Keywords: fracture fixation; internal; minimally invasive surgery; pelvis; robotics.

Figure 1

Overall view of the TiRobot system

Figure 2

Preoperative CT 3D reconstruction showed bilateral ramus of pubis fractures and left sacrum fracture

Figure 3

(A) Robot‐assisted path planning of sacroiliac screw placement in S1; (B) guiding needle placement; (C) screw placement along the guiding needle

Figure 4

(A) Robot‐assisted path planning of left pedicle screw placement. (B) Screw placement in the anterior inferior iliac spine

Figure 5

Postoperative X‐ray (A) inlet view, (B) outlet view, (C) anteroposterior view, and (D) CT 3D reconstruction showing good morphology of pelvic rings

Figure 6

Postoperative CT MPR: (A) transverse view; (B) sagittal view; and (C) coronal view showed the sacroiliac joint screws and the pedicle screws were in the safe area and no screw penetrated bone cortex