Percutaneous pedicle screw implantation for refractory low back pain: from manual 2D to fully robotic intraoperative 2D/3D fluoroscopy

Percutaneous screw placement in the lumbar spine with a modified guidance technique based on 3D CT navigation system

Several guidance techniques have been employed to increase accuracy and reduce surgical time during percutaneous placement of pedicle screws (PS). The purpose of our study was to present a modified technique for percutaneous placement of lumbar PS that reduces surgical time. We reviewed 23 cases of percutaneous PS placement using our technique for minimally invasive lumbar surgeries and 24 control cases where lumbar PS placement was done via common technique using Jamshidi needles (Becton, Dickinson and Company, Franklin Lakes, NJ, USA). An integrated computer-guided navigation system was used in all cases. In the technique modification, a handheld drill with a navigated guide was used to create the path for inserting guidewires through the pedicles and into the vertebral bodies. After drill removal, placement of the guidewires through the pedicles took place. The PS were implanted over the guidewires, through the pedicles and into the vertebral bodies. Intraoperative computed tomography was performed after screw placement to ensure optimal positioning in all cases. There were no intraoperative complications with either technique. PS placement was correct in all cases. The average time for each PS placement was 6.9 minutes for the modified technique and 9.2 minutes for the common technique. There was no significant difference in blood loss. In conclusion, this modified technique is efficient and contributes to reduced operative time.

Accuracy of a new intraoperative cone beam CT imaging technique (Artis zeego II) compared to postoperative CT scan for assessment of pedicle screws placement and breaches detection

PURPOSE

The goal of this study was to compare the accuracy of a novel intraoperative cone beam computed tomography (CBCT) imaging technique with that of conventional computed tomography (CT) scans for assessment of pedicle screw placement and breach detection.

METHODS

Three hundred and forty-eight pedicle screws were inserted in 58 patients between October 2013 and March 2016. All patients had an intraoperative CBCT scan and a conventional CT scan to verify the placement of the screws. The CBCT and CT images were reviewed by two surgeons to assess the accuracy of screw placement and detect pedicle breaches using two established classification systems. Agreement on screw placement between intraoperative CBCT and postoperative CT was assessed using Kappa and Gwet's coefficients. Using CT scanning as the gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value were calculated to determine the ability of CBCT imaging to accurately evaluate screw placement.

RESULTS

The Kappa coefficient was 0.78 using the Gertzbein classification and 0.80 using the Heary classification, indicating a substantial agreement between the intraoperative CBCT and postoperative CT images. Gwet's coefficient was 0.94 for both classifications, indicating almost perfect agreement. The sensitivity, specificity, positive predictive value and negative predictive value of the CBCT images were 77, 98, 86, and 96%, respectively, for the Gertzbein classification and 79, 98, 88, and 96%, respectively, for the Heary classification.

CONCLUSIONS

Intraoperative CBCT provides accurate assessment of pedicle screw placement and enables intraoperative repositioning of misplaced screws. This technique may make postoperative CT imaging unnecessary.

Application of a three-dimensional graft of autologous osteodifferentiated adipose stem cells in patients undergoing minimally invasive transforaminal lumbar interbody fusion: clinical proof of concept

BACKGROUND

The authors applied a scaffold-free osteogenic three-dimensional (3D) graft made of adipose-derived mesenchymal stem cells (AMSCs) in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MI-TLIF).

METHODS

Three patients (two patients and one patient with 1 and 2 levels, respectively) with degenerative spondylolisthesis underwent MI-TLIF with 3D graft made of AMSCs. To obtain the AMSCs, fatty tissue was collected from the abdomen by lipoaspiration and differentiated afterwards in our Cell/Tissue bank. Clinical outcomes, including the Oswestry Disability Index (ODI) and visual analog scale (VAS) as well as fusion status were assessed preoperatively and up to 12 months postoperatively.

RESULTS

At 12 months, all four operated AMSC levels could be assessed (n = 4). Grade 3 fusion could be confirmed at two levels out of four. Mean VAS score improved from 8.3 to 2 and ODI also improved from 47 to 31%. No donor site complication was observed. The final AMSC osteogenic product was stable, did not rupture with forceps manipulation, and was easily implanted directly into the cage with no marked modification of operating time.

CONCLUSIONS

A scaffold-free 3D graft made of AMSCs can be manufactured and used as a promising alternative for spinal fusion procedures. Nevertheless, further studies of a larger series of patients are needed to confirm its effectiveness.

Navigation, robotics, and intraoperative imaging in spinal surgery

Spinal navigation is a technique gaining increasing popularity. Different approaches as CT-based or intraoperative imaging-based navigation are available, requiring different methods of patient registration, bearing certain advantages and disadvantages. So far, a large number of studies assessed the accuracy of pedicle screw implantation in the cervical, thoracic, and lumbar spine, elucidating the advantages of image guidance. However, a clear proof of patient benefit is missing, so far. Spinal navigation is closely related to intraoperative 3D imaging providing an imaging dataset for navigational use and the opportunity for immediate intraoperative assessment of final screw position giving the option of immediate screw revision if necessary. Thus, postoperative imaging and a potential revision surgery for screw correction become dispensable.Different concept of spinal robotics as the DaVinci system and SpineAssist are under investigation.