Percutaneous antegrade scaphoid screw placement: a feasibility and accuracy analysis of a novel electromagnetic navigation technique versus a standard fluoroscopic method

Robot-assisted vs traditional percutaneous freehand for the scaphoid fracture treatment: a retrospective study

PURPOSE

The purpose of this study was to assess the efficiency, safety, and accuracy of cannulated screw fixation using a robot-assisted method compared with a traditional percutaneous freehand method.

METHODS

This retrospective clinical study included 18 patients with scaphoid fracture who underwent cannulated screw fixation by robot-assisted technique or traditional percutaneous freehand technique from June 2018 to June 2020. All patients were divided into the robot-assisted group (9 patients) or the traditional surgery group (9 patients). The operation time, blood loss, number of intra-operative fluoroscopies, fracture healing time, Mayo wrist function score, and screw implantation accuracy were recorded in the two groups.

RESULTS

The average age of the robot-assisted group was 37.9 ± 10.6 years (with a range of 30 to 52 years), there were eight males and one female, and there were six cases of scaphoid fracture on the right side and three on the left side. The average pre-operative time was 2.8 ± 0.7 days (ranging from 1 to 3 days). The average age of the traditional surgery group was 31.6 ± 6.8 years (with a range of 20 to 45 years), there were eight males and one female, and there were five cases of scaphoid fracture on the right side and four on the left side. The average pre-operative time was 2.1 ± 0.8 days (with a range of 2 to 4 days). The number of intra-operative fluoroscopies was 24.4 ± 3.5 in the traditional surgery group, whereas it was only 10.1 ± 1.9 in the robot-assisted group, which was significantly lower (P < 0.05). The average operation time of the traditional operation group was 48.4 ± 12.2 min, and that of the robot-assisted group was 32.6 ± 4.2 minutes, which was significantly shorter (P < 0.05). The angles between the actual screw position and the central axis of the scaphoid on both the coronal and sagittal post-operative CT images were 8.3° ± 2.3° and 8.8° ± 1.6° for the traditional operation group and 3.8° ± 0.8° and 4.3° ± 1.2° for the robot-assisted group, so the accuracy of the robot-assisted group was significantly higher (P < 0.05). There were no significant differences between the two groups in wrist function recovery or fracture healing time.

CONCLUSION

Robot-assisted treatment of scaphoid fracture is more accurate than traditional freehand technology, with shorter operation time and fewer intra-operative fluoroscopies. There is no difference between the two surgical techniques in intra-operative bleeding, post-operative fracture healing, or functional recovery. Robot-assisted surgery is a safe, effective, and accurate method for treating scaphoid fracture.

Cold ablation robot‐guided laser osteotomy in hand, wrist and forearm surgery—A feasibility study

Introduction

Traditional bone surgery using saws and chisels is associated with direct contact of instruments with the bone causing friction, heat and pressure and hence, damaging the bone and the surrounding soft tissues.

Method

Cold ablation laser osteotomy offers new possibilities to perform corrective osteotomies in the field of bone surgery. We introduce the technology of navigated cold ablation robot‐guided laser osteotomy, present potential applications, and preliminary pre‐clinical cadaver test results in the field of hand‐, wrist‐ and forearm surgery.

Results

The cadaver tests showed first promising results for corrections in all planes and axes using different cutting patterns.

Conclusion

Cold ablation laser osteotomy seems to be a feasible new method to perform osteotomies in the field of hand‐, wrist‐ and forearm surgery. Primary osseous stability could be achieved using various cutting patterns which could lead to reduction of the amount of hardware required for osteosynthesis. Further tests are required to proof the latter and precision.

Electromagnetic navigation reduces radiation exposure for retrograde drilling in osteochondrosis dissecans of the talus

Background

Retrograde drilling in osteochondrosis dissecans (OCD) is a widely used surgical intervention. A radiation-free electromagnetic navigation system (ENS)-based method was compared with the standard freehand fluoroscopic (SFF) method regarding clinical applicability.

Methods

We performed a clinical cohort study at a department of Orthopaedics in a Level 1 children’s hospital with 40 patients (20 SFF and 20 ENS). Retrograde drilling of the talar dome was used in patients with unstable medial OCD (MRI stage 2 according to Hepple’s revised classification; stage 2 according to the International Cartilage Repair Society). The outcome measurements were: (a) Intraoperative fluoroscopy exposure and length of surgery and (b) Postoperative serial follow-up MRIs every 6 months.

Results

22 female and 18 male patients aged 13.8 ± 1.6 years (range: 11–17 years) were included. Using the ENS technique, length of surgery was significantly reduced to 20.2 ± 6.4 min compared to 36.1 ± 11.8 min (p < 0.01) for the SFF technique. The average x-ray radiation time for the SFF technique was 23.5 ± 13.5 sec and 1.9 ± 1.7 sec for the ENS technique (p < 0.01). Radiation exposure was significantly reduced from 44.6 ± 19.7 mSv (SFF technique) to 5.6 ± 2.8 mSv (ENS technique) (p < 0.01). Intraoperative perforation of cartilage occurred once in the SFF group. Correct placement of the drilling channel was verified in all patients on follow-up MRI after six months and a timely healing was seen after two years.

Conclusions

The ENS method provides for a significant reduction in length of surgery and radiation exposure. ENS was without intraoperative cartilage perforation. The clinical and radiological follow-up parameters are comparable for SFF- and ENS-guided retrograde drilling.

Trial registration

WF – 085/20, 05/2020 “retrospectively registered” https://www.aerztekammer-hamburg.org/ethik_kommission.html.

Three-dimensional-printed patient-specific Kirschner-wire guide for percutaneous fixation of undisplaced scaphoid fractures: a cadaveric study

Undisplaced scaphoid waist fractures can be managed by percutaneous fixation. The purpose of this study is to compare percutaneous fixation using a three-dimensional (3-D)-printed guide with the conventional method in a cadaveric study. Twelve wrists were divided into two groups: standard fluroscopic technique group, and a patient-specific 3-D-printed guide group. In the patient-specific group, using high resolution CT scans, we manufactured a mould-guide including a wire guide sleeve aligned with the planned ideal path, and 3-D printed it. On postoperative CT scans we measured the angular deviation of the screw axis from the ideal axis, and compared the two groups. The angular deviation was significantly lower in the patient-specific guide group. We concluded that a 3-D-printed guide for scaphoid percutaneous fixation allows a more accurate placement of the screw than a fluoroscopy guide in our cadaveric model.

Computer-assisted Surgery for Scaphoid Fracture

The computer-assisted surgery (CAS) has significantly improved the accuracy, reliability and outcomes of traumatic, spinal, nerve surgery and many other operations with a less invasive way. The application of CAS for scaphoid fractures remains experimental. The related studies are scanty and most of them are cadaver researches. Some intrinsic defects from the registration procedure, scan and immobilization of limbs may inevitably result in deviations. Some deviations become more obvious with operations of small bones (such as scaphoid) although they are acceptable for spine and other orthopedic surgeries. We reviewed the current literatures on the applications of CAS for scaphoid operation and summarized technical principles, scan and registration methods, immobilization of limbs and their outcomes. On the basis of the data, we analyzed the limitations of this technique and envisioned its future development.

Electromagnetic Real Time Navigation in the Region of the Posterior Pelvic Ring: An Experimental In-Vitro Feasibility Study and Comparison of Image Guided Techniques

Background

Electromagnetic tracking is a relatively new technique that allows real time navigation in the absence of radiation. The aim of this study was to prove the feasibility of this technique for the treatment of posterior pelvic ring fractures and to compare the results with established image guided procedures.

Methods

Tests were performed in pelvic specimens (Sawbones^®) with standardized sacral fractures (Type Denis I or II). A gel matrix simulated the operative approach and a cover was used to disable visual control. The electromagnetic setup was performed by using a custom made carbon reference plate and a prototype stainless steel K-wire with an integrated sensor coil. Four different test series were performed: Group OCT: Optical navigation using preoperative CT-scans; group O3D: Optical navigation using intraoperative 3-D-fluoroscopy; group Fluoro: Conventional 2-D-fluoroscopy; group EMT: Electromagnetic navigation combined with a preoperative Dyna-CT. Accuracy of screw placement was analyzed by standardized postoperative CT-scan for each specimen. Operation time and intraoperative radiation exposure for the surgeon was documented. All data was analyzed using SPSS (Version 20, 76 Chicago, IL, USA). Statistical significance was defined as p< 0.05.

Results

160 iliosacral screws were placed (40 per group). EMT resulted in a significantly higher incidence of optimal screw placement (EMT: 36/40) compared to the groups Fluoro (30/40; p< 0.05) and OCT (31/40; p< 0.05). Results between EMT and O3D were comparable (O3D: 37/40; n.s.). Also, the operation time was comparable between groups EMT and O3D (EMT 7.62 min vs. O3D 7.98 min; n.s.), while the surgical time was significantly shorter compared to the Fluoro group (10.69 min; p< 0.001) and the OCT group (13.3 min; p< 0.001).

Conclusion

Electromagnetic guided iliosacral screw placement is a feasible procedure. In our experimental setup, this method was associated with improved accuracy of screw placement and shorter operation time when compared with the conventional fluoroscopy guided technique and compared to the optical navigation using preoperative CT-scans. Further studies are necessary to rule out drawbacks of this technique regarding ferromagnetic objects.