Learning curve analysis of robot-assisted percutaneous placmemt of acetabular anterior column screws

Objective To investigate the feasibility of a new computer-assisted navigation frame for percutaneous scaphoid screw placement.Methods Two fresh cadaveric upper limbs were used for percutaneous scaphoid screw placement under ISO-C3D navigation system combined with a new positioning and guidance frame.The specimens were assessed grossly and radiologically.Results Scaphoid screw placement was performed successfully using this new navigation system.Only one attempt was required for percutaneous guide wire insertion and the screws were within the safe zone of the scaphoid for both of the specimens.Conclusion This preliminary study proved the feasibility of percutaneous scaphoid screw placement using this new computer-assisted navigation frame.The accuracy and stability of this system can meet the requirement of percutaneous scaphoid screw placement in this study. Key words: Scaphoid ; Percutaneous screw placement ; Computer-assisted navigation ; Digital medicine

ObjectiveStudies have compared the safety and accuracy of robot‐assisted techniques for inserting conventional open pedicle screws for spinal surgery. However, no relevant studies have confirmed that robot‐assisted percutaneous screw placement is better than fluoroscopic percutaneous screw placement for the treatment of thoracolumbar fractures. This study compared the accuracy and safety of TiRobot‐assisted percutaneous pedicle screw placement with those of the fluoroscopy‐assisted percutaneous technique for the treatment of thoracolumbar fractures.MethodsThis retrospective study included 126 patients with thoracolumbar fractures who underwent percutaneous pedicle screw placement. Sixty‐five patients were treated with the TiRobot‐assisted technique and 61 patients were treated with the fluoroscopy‐assisted technique. Patient demographics, accuracy of screw placement (according to the Gertzbein and Robbins scale of grades A to E), screw insertion angle, radiation exposure, surgical time, intraoperative blood loss, length of hospital stay, incision length, hospital expenses, surgical site infection, and neurological injury of the TiRobot‐assisted and fluoroscopy‐assisted groups were compared using Student's t‐test, Pearson χ2 test, or Fisher's exact test.ResultsA total of 729 screws were placed (TiRobot‐assisted group: 374 screws; fluoroscopy‐assisted group: 355 screws). In the TiRobot‐assisted group, 82.8% of screws were optimally positioned (grade A); however, the placement grades of the remaining screws were categorized as grade B (13.3%), grade C (3.2%), and grade D (0.5%). In the fluoroscopy‐assisted group, 66.7% of the screws were optimally positioned (grade A); however, the placement grades of the remaining screws were categorized as grade B (21.4%), grade C (7.6%), grade D (3.6%), and grade E (0.5%). The proportion of clinically acceptable screws (grade A or B) was greater in the TiRobot‐assisted group than in the fluoroscopy‐assisted group. Additionally, the TiRobot‐assisted group had a significantly larger mean screw insertion angle (22.27° ± 5.48° vs 20.55° ± 5.15°), larger incision length (13.86 ± 1.24 cm vs 12.77 ± 1.43 cm), and higher hospital expenses (69061.55 ± 7166.60 yuan vs 59383.85 ± 5019.64 yuan) than the fluoroscopy‐assisted group. There were no significant differences in the intraoperative blood loss, length of hospital stay, and rates of surgical site infection and neurological injury in both groups (p > 0.05). However, the TiRobot‐assisted group had significantly better surgical times, radiation times, and radiation exposure than the fluoroscopy‐assisted group (p < 0.05).ConclusionsPercutaneous TiRobot‐assisted pedicle screw placement is a safe, useful, and potentially more accurate alternative to the percutaneous fluoroscopy‐assisted technique for treating thoracolumbar fractures.

With interest we read the letter by Rob D. Dickerman regarding our article “comparison of open versus percutaneous pedicle screw insertion in a sheep model” published in the ESJ. Our reply to the authors and colleagues is as follows: Percutaneous pedicle screw insertion represents a considerably novel technique, which has been recently introduced in the literature. Up to now, only a few studies have been published, most of them focused on technical matters and postoperative assessment of screw placement [2, 6–11]. Consequently, the available data about functional outcome are sparse. Grass and colleagues investigated procedure and image converter time, blood loss and muscle damage by needle-EMG in a controlled prospective setup representing an evidence level II-1 [3]. They found a higher loss of blood and neurophysiological signs of muscle damage in the open group. In a small retrospective study, Kim et al. analyzed cross sectional muscle areas by MRI in patients either treated with open or percutaneous pedicle screw insertion. They found a significant decrease of the multifidus muscle size in the group which received open pedicle screw insertion. However, clinical scores revealed no difference between the two groups [4]. In our study, we could for the first time demonstrate a clear benefit in terms of blood loss and CK liberation by percutaneous screw placement in a controlled and experimental setting. To our knowledge there are no further studies representing a similar high level of evidence on this topic. The author of the letter claims, that there was substantial literature on the benefits of minimally invasive spine surgery, including less muscle damage, faster recovery and shorter hospitalization and that open lumbar fusions had significantly higher muscle damage in comparison to minimally invasive procedures. However, looking at the cited literature it becomes clear that Arts as well as Kumbhare mainly addressed CK liberation in patients undergoing decompression or disc surgery while only a small minority of their patients was treated with pedicle screws [1, 5]. Further, the cited studies include neither a comparison between open and percutaneous pedicle screw insertion nor any data regarding recovery and hospitalization. The author of the letter mentions the alternative to deliver the pedicle screw percutaneously over a guidewire. Due to the very hard bone cortex of the sheep used in our study the pedicles had to be opened and inserted with a machine drill, so that the use of cannulated or wire guided screws was not an option in our study. The author of the letter presents preliminary results of several minimally invasive screw systems and used CK liberation as the main outcome factor. We agree with the author, that CK represents an important and feasible parameter to assess muscle damage. However, the clinical relevance of elevated serum CK levels after surgical procedures remains controversial and definitely, more data with regard to functional outcome and quality of life are required here [1]. A further concern is the longer exposure time to radiation with placement of percutaneous pedicle screws. During the open approach a clear orientation is provided by the anatomical landmarks of the lumbar spine and access to the pedicle can be easily obtained without image converter. In a percutaneous setting, those anatomical landmarks are lacking, which explains the longer radiation exposure time we found in the percutaneous group. The author of the letter disagreed with this point based on his own clinical observations. However, this statement remains speculative and unsupported, since he did not provide any evidence from own data, but only referred to previous studies, which do not necessarily match our experimental design. The author of the letter claims that, in experienced hands, percutaneous pedicle screw placement decreases operative time, blood loss, muscle damage and radiation exposure, while also significantly shortening hospitalization time and recuperative time. As outlined above, we do not believe that there is enough evidence from experimental and clinical studies, to support such a statement. Further, we would like to encourage the author to publish more of his data. We feel that this would contribute to the issue and would enable us and other interested groups to openly discuss whether percutaneous pedicle screw placement really provides an evidence based benefit or not.

Background: The gold standard for percutaneous pedicle screw placement is 2-dimensional (2D) fluoroscopy. Data are sparse on the accuracy of 3-dimensional (3D) navigation percutaneous screw placement in minimally invasive spine procedures. Objective: We sought to compare a single surgeon's percutaneous pedicle screw placement accuracy using 2D fluoroscopy versus 3D navigation, as well as to investigate the effect of facet orientation on facet violation when using 2D fluoroscopy. Methods: We conducted a retrospective radiographic study of consecutive cohort of patients who underwent percutaneous lumbar instrumentation using either 2D fluoroscopy or 3D navigation. All procedures were performed by a single surgeon at 2 academic institutions between 2011 and 2018. Radiographic measurement of screw accuracy was assessed using a postoperative computed tomographic scan. The primary outcome was facet violation, and secondary outcomes were endplate/tip breaches, the Gertzbein-Robbins classification for cortical breaches, and the Simplified Screw Accuracy grade. Statistical comparisons were made between screws placed using 2D fluoroscopy versus 3D navigation. Axial facet angles were also measured to correlate with facet violation rates. Results: In the 138 patients included, 376 screws were placed with fluoroscopy and 193 with navigation. Superior (unfused) level facet violation was higher with 2D fluoroscopy than with 3D navigation (9% vs 0.5%), which comprises the main cause for poor screw placement. Axial facet angles exceeding 45° at L4 and 60° at L5 were correlated with facet violations. Conclusion: This retrospective study found that 3D navigation is associated with lower facet violation rates in percutaneous lumbar pedicle screw placement when compared with 2D fluoroscopy. These findings suggest that 3D navigation may be of particular value when facet joints are coronally oriented.

Minimally invasive surgery (MIS) and anterior (ALIF), transforaminal (TLIF), or lateral lumbar interbody fusion (LLIF) often require percutaneous pedicle screw fixation (PSF) to achieve circumferential fusion. Robotic guidance technology may augment workflow to improve screw placement and decrease operative time. To report surgical experience with robotically assisted percutaneous screw placement following LLIF. Data from fusions with robotically assisted PSF in prone or lateral decubitus positions was reviewed. A CT-guided robotic guidance arm was used for screw placement (Excelsius GPS™, Globus Medical Inc, Audubon, Pennsylvania). Postoperative CT imaging facilitated screw localization. 3-dimensional and 2-dimensional coordinates of the screw tip and tail were calculated and compared with a target trajectory to calculate targeting errors. Breach was defined as a violation of the lateral or medial pedicle wall. Robotic-guided screw placement was successful in 28/31 patients. In those patients, 116/116 screws were successfully implanted. The breach rate was 3.4% (4/116). Across 17 patients (70 screws), mean 3-D accuracy was 5.0±2.4 mm, mean 2-D accuracy was 2.6±1.1 mm, and mean angular offset was 5.6±4.3° with corresponding intraclass correlation coefficients (ICC) of 0.775 and 0.693. 3-dimensional accuracy correlated with age (R=0.306, P=.011) and BMI (R=0.252, P=.038). Accuracy did not significantly differ among vertebral body levels (P>.22). Mean operative time for MIS-TLIF and percutaneous screws was 277±52 and 183±54 min, respectively. Operative time did not significantly decrease across either group (P>.187). The Excelsius GPS™ robotic guidance system allows accurate PSF in most cases with 2 mm 2-D accuracy. Future studies are needed to demonstrate the utility of this novel guidance system and workflow improvement.

Study Design:A cadaveric study to determine the accuracy of percutaneous screw placement in the thoracic spine using standard fluoroscopic guidance.Summary of Background Data:While use of percutaneous pedicle screws in the lumbar spine has increased rapidly, its acceptance in the thoracic spine has been slower. As indications for pedicle screw fixation increase in the thoracic spine so will the need to perform accurate and safe placement of percutaneous screws with or without image navigation. To date, no study has determined the accuracy of percutaneous thoracic pedicle screw placement without use of stereotactic imaging guidance.Materials and Methods:Eighty-six thoracic pedicle screw placements were performed in four cadaveric thoracic spines from T1 to T12. At each level, Ferguson anterior–posterior fluoroscopy was used to localize the pedicle and define the entry point. Screw placement was attempted unless the borders of the pedicle could not be delineated solely using intraoperative fluoroscopic guidance. The cadavers were assessed using pre- and postprocedural computed tomography (CT) scans as well as dissected and visually inspected in order to determine the medial breach rate.Results:Ninety pedicles were attempted and 86 screws were placed. CT analysis of screw placement accuracy revealed that only one screw (1.2%) breached the medial aspect of the pedicle by more than 2 mm. A total of four screws (4.7%) were found to have breached medially by visual inspection (three Grade 1 and one Grade 2). One (1.2%) lateral breach was greater than 2 mm and no screw violated the neural foramen. The correlation coefficient of pedicle screw violations and pedicle diameter was found to be 0.96.Conclusions:This cadaveric study shows that percutaneous pedicle screw placement can be performed in the thoracic spine without a significant increase in the pedicle breach rate as compared with standard open techniques. A small percentage (4.4%) of pedicles, especially high in the thoracic spine, may not be safely visualized.

Percutaneous pedicle screw placement under single dimensional fluoroscopy with a designed pedicle finder—a technical note and case series

Percutaneous and open iliac screw safety and accuracy using a tactile technique with adjunctive anteroposterior fluoroscopy

A randomized controlled study. To introduce a new pilot hole preparation system for percutaneous pedicle screw placement and investigate its efficiency and safety in comparison with the conventional method. Placing screws accurately, rapidly, and safely with less radiation exposure is critical for minimally invasive lumbar interbody fusion (LIF). Optimizing pilot hole preparation instruments has important clinical implications. A total of 60 patients (180 screws) were included in this study. All patients were randomized into two groups (new system vs. conventional method) and performed single-level minimally invasive percutaneous fixation, interbody fusion, and unilateral decompression. Basic information, time of pilot hole preparation, time of screw placement, and fluoroscopy time were recorded. Screw placement accuracy was graded based on the Gertzbein-Robbins scale, and the angle between the screw axis and the pedicle axis was collected in postoperative CT. There was no statistical difference in basic information between the 2 groups. The mean time of single pilot hole preparation was 4.08±1.01 minutes in the new system group and 5.34±1.30 minutes in the conventional method group ( P <0.001). The time of single screw placement was significantly shorter in the new system group (0.82±0.20 vs. 1.72±0.33min), and the fluoroscopy time was also less in the new system group (13.70±3.42 vs. 19.95±5.50s) ( P <0.001). Screw placement accuracy assessment showed that there were 85 (94.45%) A-grade screws in the new system group while 76 (84.44%) A-grade screws in the conventional method group ( P =0.027). The new pilot hole preparation system has shown significant reductions in the time of pilot hole preparation, time of screw placement, and radiation exposure, and has good clinical application value.

Computer-Assisted Navigation for Dorsal Percutaneous Scaphoid Screw Placement: A Cadaveric Study

Objective To investigate the clinical results of three-dimensional navigation for placement of percutaneous sacroiliac joint screws in the internal fixation of sacroiliac complex injury. Methods A retrospective study was conducted of the 30 patients who had been treated for sacroiliac complex injury from March 2015 to January 2016 and fully followed up. They were 22 males and 8 females, aged from 25 to 63 years (average, 44.2 years). According to Tile classification for pelvic fractures, there were 14 cases of type B (type B1 in 6, type B2 in 6 and type B3 in 2), and 16 cases of type C (type C1 in 9, type C2 in 5, and type C3 in 2). Three cases complicated with preoperative injury to lumbosacral trunk were treated with anterior plate and percutaneous sacroiliac joint screws; the other 27 cases with internal fixation with percutaneous sacroiliac joint screws. The placement of screws was aided by three-dimensional navigation. The time for each screw placement and X-ray exposure was recorded intraoperatively. Postoperative reduction quality was assessed using Matta radiological criteria and Majeed criteria was used at the final follow-ups to evaluate the pelvic function. Results Altogether 36 sacroiliac joint screws were inserted in the 30 patients under three-dimensional navigation. The time for each screw placement ranged from 28 to 40 minutes (average, 33.2 minutes); the intraoperative X-ray exposure time ranged from 1.2 to 2.5 minutes (average, 1.4 minutes). No infection occurred at either incision or placement site. According to Matta radiological criteria, reduction was excellent in 16, good in 11 and fair in 3, giving an excellent to good rate of 90.0%. The follow-up time for the 30 patients ranged from 6 to 12 months (average, 10.6 months). At the final follow-ups, X-ray and CT three-dimensional reconstruction showed fine fracture union and no loosening or breakage of screws in all. By the Majeed criteria, the pelvic function was excellent in 17 cases, good in 8 cases, fair in 4 cases, and poor in one, giving a good to excellent rate of 83.3%. Conclusion Three-dimensional navigation for placement of percutaneous sacroiliac joint screws in internal fixation of sacroiliac complex injury can lead to precise placement, minimal invasion, safety and effectiveness. Key words: Sacroiliac joint; Wounds and injuries; Fracture fixation, internal; Bone nails; Surgery, computer-assisted

A surgical simulation study in human cadaver spine specimens was conducted to evaluate the accuracy of 3 different surgical navigation systems compared to standard fluoroscopy in the percutaneous placement of iliosacral screws. To compare the accuracy of percutaneous iliosacral screw placement using standard fluoroscopy, computer-assisted fluoroscopic image guidance, Iso-C3D image guidance (Medtronic Surgical Navigation Technologies, Louisville, CO), and electromagnetic fluoroscopic image guidance. Conventional percutaneous sacroiliac screw placement has a malposition rate as high as 15%, as reported in the English-speaking literature (Hinsche et al [Clin Orthop Relat Res 2002;395:135-44] and Templeman et al [Clin Orthop Relat Res 1996;329:194-8]). Iso-C3D and computer-assisted image guidance technologies have been proposed to increase this accuracy rate. Two iliosacral screws were placed bilaterally (4 screws) in each of 4 cadavers using standard fluoroscopy, computer-assisted fluoroscopic image guidance, Iso-C3D image guidance, and electromagnetic fluoroscopic image guidance. Screw positions were analyzed by computerized tomography after instrumentation and assigned a score based on deviation from ideal screw position. The StealthStation with FluoroNav (Medtronic Surgical Navigation Technologies) appeared to provide the highest accuracy of all guidance techniques. This result was more accurate than standard fluoroscopy. Computer-assisted fluoroscopy based image navigation appears to be more accurate than standard fluoroscopy in placing these screws. However, errors may occur with all techniques. Further refinement in registration procedures may highly improve the accuracy of percutaneous screw placement in a variety of spinopelvic procedures.

Pedicle axis view combined by sacral mapping can decrease fluoroscopic shot count in percutaneous iliosacral screw placement

Lumbar fusion using lateral single position surgery (LSPS) gained popularity during the last few years. While prone percutaneous pedicle screw placement is well described, placing percutaneous pedicle screws with the patient in the lateral position is considered the most complicated part of LSPS. In this article we describe the fluoroscopy navigated technique for lateral percutaneous screw placement using the tunnel view technique. The radiologic background and principles of the tunnel view technique are described. In addition, the special positioning of the patient, the C-arm and the surgical technique is discussed in detail. This technique is used as the standard for percutaneous screw placement in the prone or lateral positions in our department since 2017. Since the introduction of this technique we have had 0% reoperation rate for symptomatic malpositioned pedicle screws. The tunnel view technique simplifies pedicle screw placement while allowing for permanent observation of pedicle walls and the superior joint surface during placement of the Jamshidi needle. It also allows for confirmation of intrapedicular position of the screw after its implantation. This technique is safe and feasible in our clinical experience.

Increasing popularity of minimally invasive surgery for lumbar fusion has led to dependence upon intraoperative fluoroscopy for pedicle screw placement, because limited muscle dissection does not expose the bony anatomy necessary for traditional, freehand techniques nor for registration steps in image-guidance techniques. This has raised concerns about cumulative radiation exposure for both surgeon and operating room staff. The recent introduction of the O-arm Multidimensional Surgical Imaging System allows for percutaneous placement of pedicle screws, but there is limited clinical experience with the technique and data examining its accuracy. We present the first large clinical series of percutaneous screw placement using navigation of O-arm imaging and compare the results with the fluoroscopy-guided method. A retrospective review of a 24-month period identified patients undergoing minimally invasive lumbar interbody fusion. The O-arm was introduced in the middle of this period and was used for all subsequent patients. Accuracy of screw placement was assessed by examination of axial computed tomography or O-arm scans. The fluoroscopy group included 141 screws in 42 patients, and the O-arm group included 205 screws in 52 patients. The perforation rate was 12.8% in the fluoroscopy group and 3% in the O-arm group (P < .001). Single-level O-arm procedures took a mean 200 (153-241) minutes, whereas fluoroscopy took 221 (178-302) minutes (P < .03). Percutaneous pedicle screw placement with the O-arm Multidimensional Intraoperative Imaging System is a safe and effective technique and provided improved overall accuracy and reduced operative time compared with conventional fluoroscopic techniques.