Computer-assisted Surgery Group Research Articles

Image-Based Computer-Assisted Total Knee Arthroplasty Leads to Lower Variability in Coronal Alignment

In a prospective randomized controlled trial, one group of 50 patients had total knee arthroplasty using conventional instruments; another group of 50 patients had total knee arthroplasty using a fluoroscopy-based computer navigation system. The variability of postoperative alignment of the lower limb in the coronal and saggital plane, early clinical outcome scores, and morbidity of the procedure were compared. In addition, the image-based computer navigation system was used to assess the following presumptions: the accuracy of the calculation of the kinematic center of rotation of the hip and the reliability of full-leg standing xrays in determining overall coronal alignment of the lower limb. Variability in the coronal plane was significantly reduced in the computer-assisted surgery group compared with the conventional group (p < 0.0001). Early clinical outcome and complication rates were similar for both groups. The correlation between full-leg standing xrays and the computer navigation system for determining the mechanical alignment of the lower limb in the coronal plane was high (r = 0.987). The maximum deviation between the calculated kinematic center of rotation of the hip and the fluoroscopically determined anatomic center of the hip was 5 mm (mean, 1.6 mm). An image based computer-assisted system can be safely used and leads to a consistent and perfect postoperative alignment in the coronal plane.

No benefits with computer assistance in triple pelvic osteotomy.

We evaluated computer-assisted surgery (CAS) used for 21 triple pelvic osteotomies on 20 patients with symptomatic acetabular dysplasia and compared the intraoperative and immediate postoperative data with those of 32 patients who underwent 40 pelvic osteotomies without CAS. The use of the CAS system was abandoned during 9/21 operations mostly because of technical and CT data failure. The peroperative blood loss and duration of surgery were greater, while neurovascular damage occurred less often in the CAS group. We found that the CAS system for pelvic osteotomy was not better than conventional methods.

Reduction in Variability of Acetabular Cup Abduction Using Computer Assisted Surgery: A Prospective and Randomized Study

Optimal orientation of the acetabular component of a total hip prosthesis is an important factor in determining the early and long-term result of a total hip arthroplasty (THA). Conventional positioning of the cup component is usually done using a free-hand method, or with the help of a mechanical acetabular alignment guide. However, these methods have proven to be inaccurate, and a great variation in orientation of the cup is found postoperatively. In this study, we wished to determine if the variability of the abduction angle of acetabular cups could be reduced with the use of computer navigation. The abduction angles of the acetabular components of three groups of 50 THAs were assessed. In the first group, a free-hand method was used to position the cup component. This group was operated in the period before we started using computer navigation for hip surgery. In the second group, CT-based computer navigation was used to plan and help position the cup. The third group consisted of 50 THA cases in which a free-hand method was used to position the cup, although these procedures were performed in the period after we had begun using the Computer Assisted Surgery (CAS) system. The variability in cup abduction angle was assessed in all three groups and compared. There was a significant reduction in variability in the CAS group compared to the first group. There was also a reduction in variability in the CAS group compared to the third group, although this was not statistically significant. It is concluded that the use of computer navigation helped the surgeon to place the cup component with less variability of the abduction angle, and, more importantly, we found that no cups were placed in the more extreme positions (outliers).

Clinical results of percutaneous pelvic surgery. Computer assisted surgery using ultrasound compared to standard fluoroscopy.

This study presents early results of clinical experience with the application of Computer Assisted Surgery (CAS) to percutaneous iliosacral screwing, with comparison to a historical series of patients treated using percutaneous fluoroscopy. Four patients were instrumented using a CAS system, with 10 screws being inserted. Thirty patients were treated by percutaneous fluoroscopic screwing, with 51 screws being inserted. The follow-up assessment included the following criteria; operative time, parameters of radiation exposure, neurological examination, screw placement evaluation on CT-scan, antalgic drug consumption, pain, Majeed grading, and loosening of implants. In the CAS group, the average radiation time was 0.35 min per patient and 0.14 min per screw. No trajectories outside the bone and no postoperative neurological deficits were found. In the fluoroscopic group, the average radiation time was 1.03 min per patient and 0.6 min per screw. Twelve screws had outside-bone trajectories, and iatrogenic neurological deficits were found in seven patients. The average operative time was 50 min in the CAS group and 35 min in the fluoroscopic group. The present CAS technique shows better placement of iliosacral screws, with no outside-bone trajectories and lower radiation exposure.

Clinical Results of Percutaneous Pelvic Surgery. Computer Assisted Surgery Using Ultrasound Compared to Standard Fluoroscopy

This study presents early results of clinical experience with the application of Computer Assisted Surgery (CAS) to percutaneous iliosacral screwing, with comparison to a historical series of patients treated using percutaneous fluoroscopy. Four patients were instrumented using a CAS system, with 10 screws being inserted. Thirty patients were treated by percutaneous fluoroscopic screwing, with 51 screws being inserted. The follow-up assessment included the following criteria; operative time, parameters of radiation exposure, neurological examination, screw placement evaluation on CT-scan, antalgic drug consumption, pain, Majeed grading, and loosening of implants. In the CAS group, the average radiation time was 0.35 min per patient and 0.14 min per screw. No trajectories outside the bone and no postoperative neurological deficits were found. In the fluoroscopic group, the average radiation time was 1.03 min per patient and 0.6 min per screw. Twelve screws had outside-bone trajectories, and iatrogenic neurological deficits were found in seven patients. The average operative time was 50 min in the CAS group and 35 min in the fluoroscopic group. The present CAS technique shows better placement of iliosacral screws, with no outside-bone trajectories and lower radiation exposure.

Efficacy of computed tomographic image--guided endoscopic sinus surgery in residency training programs.

To determine the efficacy of computed tomographic image-guided endoscopic surgery in the hands of inexperienced surgeons. Four second-year otolaryngology residents, with no prior experience performing ethmoidectomies, performed endoscopic sinus surgery (ESS) on formalin-fixed human cadaveric specimens with and without the aid of computer-assisted surgery (CAS). Each resident was asked to identify critical sinus, orbital, and skull base structures while performing a total ethmoidectomy and multiple sinusotomies. Their surgical accuracy (percentage of correctly identified structures), total operative time, and incidence of major complications were recorded for each side. A total of 16 sides were evaluated (8 with and 8 without CAS). Statistical significance between groups was determined by means of Pearson's chi2 analysis. Statistical analysis showed a significant difference (P = .001) in the mean accuracy of identifying critical anatomical landmarks between the CAS (97%) and non-CAS (76.8%) groups. Although not statistically significant, operative time appeared to be longer in the group using CAS (average of 67 vs. 80 min). Three major intracranial complications were documented only in the group not using CAS. Although, unquestionably, a thorough knowledge of the anatomy remains essential for performing ESS, CAS improves surgical accuracy and reduces the risk of major intracranial or intraorbital complications for residents. In additional, our data suggest that this technology may enhance surgical efficiency and improve the learning curve by reducing operative time (below one's normal baseline) while maintaining a greater than 90% accuracy in identifying critical anatomical landmarks.