Computer-assisted Navigation System Research Articles

Stereotactic image-guided microwave ablation of hepatocellular carcinoma using a computer-assisted navigation system.

Ablation plays an important role in the treatment of hepatocellular carcinoma. Because image-guided navigation technology has recently entered the clinical setting, we aimed to analyse its safety, therapeutic and procedural efficiency. Retrospective analysis of patients treated with stereotactic image-guided microwave ablation (SMWA) between January 2015 and December 2017. Interventions were performed using computertomography-guidance with needle trajectory, ablation planning and automatic single-marker patient registration. Needle placement and ablation coverage was controlled by image fusion under general anaesthesia with jet-ventilation. In total 174 ablations were performed in 88 patients during 119 interventions. Mean age was 66 (46-84) years, 74 (84.1%) were men and 74% were Child Pugh Class A. Median tumour size was 16 (4-45) mm, 62.2% were BCLC A. Median lateral and longitudinal error of needle placement were 3.2 (0.2-14.1) and 1.6 (0-15.8) mm. Median one tumour (1-4) was ablated per session. One patient developed a Dindo IIIb (0.8%) complication, six minor complications. After re-ablation of 12 lesions, an efficacy rate of 96.3% was achieved. Local tumour progression was 6.3% (11/174). Close proximity to major vessels was significantly correlated with local tumour progression (P<.05). Median overall follow-up was 17.5months after intervention and 24months after initial diagnosis. BCLC stage, child class and previous treatment were significantly correlated with overall survival (P<.05). Stereotactic image-guided microwave ablation is a safe and efficient treatment for HCC offering a curative treatment approach in general and in particular for lesions not detectable on conventional imaging or untreatable because of difficult anatomic locations.

Accuracy of Acetabular Component Positioning Using Computer-assisted Navigation in Direct Anterior Total Hip Arthroplasty.

Background Appropriate component positioning in total hip arthroplasty (THA) is imperative for long-term survivorship. C-arm fluoroscopy provides visual guidance in the direct anterior approach (DAA), but it is limited by qualitative properties. Conversely, imageless computer-assisted navigation systems (CAS) provide surgeons with intraoperative, three-dimensional (3D) quantitative measurements for cup position, although the accuracy of such systems has not been extensively addressed in the DAA. We evaluated the ability of an imageless CAS to deliver measurements for acetabular cup position with accuracy in the DAA.Materials and methods A retrospective analysis of 69 primary THA procedures was conducted. Acetabular cup position measurements (anteversion and inclination) obtained intraoperatively by imageless navigation were compared to standard, postoperative anteroposterior pelvic radiographic measurements. Statistical comparisons were made using the Bland-Altman technique.Results The mean difference between device and radiographic measurements for anteversion was 3.4° (standard deviation (SD): 4.1°; absolute mean difference (ABS): 4.2°), and 4.0° for inclination (SD: 3.6°; ABS: 4.3°). Bland-Altman analysis demonstrated excellent agreement; 93% (64/69) and 97% (67/69) of anteversion pairings fell within the statistical and clinical limits of agreement, whereas 94% (65/69) and 100% (69/69) of inclination pairings were within the statistical and clinical limits, respectively.Conclusions Measurements obtained intraoperatively for acetabular cup position using imageless navigation in the DAA are agreeable with the current clinical standard.

Femoral Component Alignment with a New Extramedullary Femoral Cutting Guide Technique.

Background:Intramedullary (IM) or extramedullary (EM) mechanical guides are used as alignment tools during total knee arthroplasty (TKA) surgery. The EM guide is less invasive; however, the IM mechanical guide is the preferred option since it has shown superior outcomes in several studies. Picture archive and communication system (PACS) images, if available, are extensively used for preoperative planning and intraoperative guidance. This retrospective study compared TKA outcomes using the conventional IM guide and a new EM technique which uses PACS image for preoperative and intraoperative assessment bone resection. To the best of our knowledge, this is the first study with the new EM technique.Materials and Methods:The study was performed on 205 knees (190 patients) for TKA from 2011 to 2013. The perioperative blood loss and the postoperative alignment angles were assessed for both mechanical guides. The angles were measured on the radiographs of the patient. The blood loss was assessed by the blood accumulated in the hemovac drain during the surgery and until 3 days after the surgery.Results:The new EM guide provided similar postoperative alignment as that obtained with the IM guide.Conclusion:The EM-guided method for femoral bone cutting using PACS films in TKA is as good as the IM method. The additional advantages of less injury to the bone and less fat emboli load to the cardiopulmonary system with the EM method makes it an attractive choice for routine, especially in the elderly and/or simultaneous bilateral, TKA in hospitals without modern computer-assisted navigation systems.

Anterior pelvic plane registration accuracy and cup position measurement using ultrasound- and pointer-based navigation in primary total hip arthroplasty.

Incorrect cup positioning in primary total hip arthroplasty is known as a risk factor for early implant failure. The use of navigation systems leads to more accurate cup positioning. The aim of this study was to compare the registration accuracy of the anterior pelvic plane and the measurement accuracy of the definite cup position for a pointer computer-assisted orthopaedic navigation system (P-CAOS) and an ultrasound-based navigation tool (US-CAOS) in an intra-individual study design. Anterior pelvic plane registration was performed in 44 patients receiving a primary total hip arthroplasty with P-CAOS and US-CAOS. The cup implantation was performed using US-CAOS. Intraoperatively, the cup position was assessed using P-CAOS and US-CAOS. The postoperative cup position was determined via CT scan. Inclination and anteversion errors were calculated using intraoperative values and CT data. All operations were performed by a single, high-volume surgeon using a minimally invasive anterolateral approach. The mean inclination error was 0.9∘ in the US-CAOS group and -1.1∘ in the P-CAOS group. This was not statistically significant. The mean anteversion error was significantly reduced (p< 0.001) in the US-CAOS group (1.4∘) compared to the P-CAOS group (-8.0∘). Significantly more cups (23 of 44; 52%) in the P-CAOS group were outliers regarding to the defined anteversion error range of 15∘± 10∘. Outliers in the US-CAOS group amounted to two (of 44; 5%) (p< 0.001). The number of outliers regarding the inclination error range of 40∘± 10∘, did not differ significantly between the P-CAOS (2; 5%) and US-CAOS (1; 2%) group. We were able to show a systematic anterior pelvic plane registration error in this intraindividual study design. US-CAOS based APP landmark registration showed to be significantly more precise compared to P-CAOS registration. The anteversion error of the cup using US-CAOS showed to be significantly reduced compared to the P-CAOS method.

A non-invasive biomechanical device to quantify knee rotational laxity: Verification of the device in human cadaveric specimens

BackgroundBiomechanical measurement tools have been developed and widely used to precisely quantify knee anterior-posterior laxity after anterior cruciate ligament (ACL) injury. However, validated objective device to document knee rotational laxity, though being developed by different researchers, are not yet widely used in the daily clinical practice. A new biomechanical device was developed to quantify knee internal and external rotations. MethodsThe reliability of the new biomechanical device which measures knee rotations were tested. Different torques (1-10Nm) were applied by the device to internally and externally rotate human cadaveric knees, which were held in a flexion angle of 30°. The rotations were measured by the device in degrees. There were two independent testers, and each tester carried out three trials. Intra-rater and inter-rater reliability were quantified in terms of intraclass correlation (ICC) coefficient among trials and between testers. The device was verified by the comparison with a computer assisted navigation system. ICC was measured. Mean, standard deviation and 95% confident interval of the difference as well as the root mean square difference were calculated. The correlations were deemed to be reliable if the ICC was above 0.75. ResultsThe intra-rater and inter-rater reliability achieved high correlation for both internal and external rotation, ranged from 0.959 to 0.992. ICC between the proposed meter and the navigation system for both internal and external rotation was 0.78. The mean differences were 2.3° and 2.5° for internal and external rotation respectively. ConclusionsA new knee rotational laxity meter was proposed in this study. Its reliability was verified by showing high correlation among trials. It also showed good correlation to a gold standard of measurement. It might be used to document knee rotational laxity for various purposes, especially after ACL injury, after further validation of the device in human subjects.

Optimal position of lipped acetabular liners to improve stability in total hip arthroplasty\u2014an intraoperative in vivo study

BackgroundLipped or elevated acetabular liners are frequently used in total hip arthroplasty to improve stability. However, the optimal position of the lip is not known. The purpose of this study was to determine the optimal position of lipped acetabular liners in total hip arthroplasty performed with a posterior approach.MethodsIn 14 hips, lipped trial liners were placed intraoperatively in various positions around the posterior clock-face of the implanted acetabular shell component. For each liner position, stability of the hip was tested at maximal hip flexion with gradually increasing internal rotation until subluxation occurred, at which point the position of the hip was measured using smartphone accelerometer-based goniometers. Smartphone goniometers were first validated against a computer-assisted navigation system. Post-operative radiographs were analyzed for cup inclination angle, cup anteversion angle, and femoral offset.ResultsMean cup inclination angle in our series was 31° ± 6°. The most common liner position that imparted the greatest stability to posterior subluxation was posteriorly and inferiorly (4 o’clock position for left hip, or 8 o’clock position for right hip). The range for most stable liner position for different patients varied from postero-superior (11 o’clock/1 o’clock position) to directly inferior (6 o’clock position). Comparing a non-lipped liner to a lipped liner placed in the optimal position, the average difference in internal rotation gained before dislocation was 23°. There was no association between cup inclination or anteversion angle with liner position of greatest stability.ConclusionIn hip replacements performed through a posterior approach and with mean cup inclination angle of 31° ± 6°, placing the lip of the elevated liner in the postero-inferior quadrant may impart more stability than in the postero-superior quadrant.

Minimal Increase in Total Hip Arthroplasty Surgical Procedural Time with the Use of a Novel Surgical Navigation Tool.

Background:Computer-assisted navigation has proven effective at improving the accuracy of component placement during Total Hip Arthroplasty (THA); however, the material costs, line-of-site issues and potential for significant time increases have limited their widespread use.Objective:The purpose of this study was to investigate the impact of an imageless navigation device on surgical time, when compared with standard mechanical guides.Methods:We retrospectively reviewed prospectively collected data from 61 consecutive primary unilateral THA cases (posterior approach) performed by a single surgeon. Procedural time (incision to closure) for THA performed with (intervention) or without (control) a computer-assisted navigation system was compared. In the intervention group, the additional time associated with the use of the device was recorded. Mean times were compared using independent samples t-tests with statistical significance set a priori at p<0.05.Results:There was no statistically significant difference between procedural time in the intervention and control groups (102.3±28.3 mins vs. 99.1±14.7 mins, p=0.60). The installation and use of the navigation device accounted for an average of 2.9 mins (SD: 1.6) per procedure, of which device-related setup performed prior to skin incision accounted for 1.1 mins (SD: 1.1) and intra-operative tasks accounted for 1.6 mins (SD: 1.2).Conclusion:In this series of 61 consecutive THAs performed by a single surgeon, the set-up and hands-on utilization of a novel surgical navigation tool required an additional 2.9 minutes per case. We suggest that the intraoperative benefits of this novel computer-assisted navigation platform outweigh the minimal operative time spent using this technology.

Image-Guided Spinal Surgery and Robotics in MIS: Where Are We Now?

Use of pedicle screws is widespread in spinal surgery for degenerative, traumatic, and oncological diseases. The conventional technique is based on the recognition of anatomic landmarks, preparation and palpation of cortices of the pedicle under control of an intraoperative C-arm (iC-arm) fluoroscopy. With these conventional methods, the median pedicle screw accuracy ranges from 86.7% to 93.8%, even if perforation rates range from 21.1% to 39.8%.The development of novel intraoperative navigational techniques, commonly referred to as image-guided surgery (IGS), provide simultaneous and multiplanar views of spinal anatomy. IGS technology can increase the accuracy of spinal instrumentation procedures and improve patient safety. These systems, such as fluoroscopy-based image guidance ("virtual fluoroscopy") and computed tomography (CT)-based computer-guidance systems, have sensibly minimized risk of pedicle screw misplacement, with overall perforation rates ranging from between 14.3% and 9.3%, respectively."Virtual fluoroscopy" allows simultaneous two-dimensional (2D) guidance in multiple planes, but does not provide any axial images; quality of images is directly dependent on the resolution of the acquired fluoroscopic projections. Furthermore, computer-assisted surgical navigation systems decrease the reliance on intraoperative imaging, thus reducing the use of intraprocedure ionizing radiation. The major limitation of this technique is related to the variation of the position of the patient from the preoperative CT scan, usually obtained before surgery in a supine position, and the operative position (prone). The next technological evolution is the use of an intraoperative CT (iCT) scan, which would allow us to solve the position-dependent changes, granting a higher accuracy in the navigation system.

Treatment of Sagittal Fracture of the Zygomatic Arch Root Assisted by Surgical Navigation Technology.

Sagittal fracture at the temporal root of the zygomatic arch often occurs as a part of zygomaticomaxillary fractures. The authors described the application of computer-assisted navigation in the lag screw insertion for the fixation of sagittal fracture at the temporal root of zygomatic arch. Using the presurgical planning of the computer-assisted navigation system, the trajectory of lag screw insertion was designed, and the insertion depth was calculated. In the presurgical planning, the trajectory of screw insertion was placed with an anterior inclination of 10° to 15° (mean: 12.24°), and the screw insertion depth was 9.0 to 12.0 mm (mean: 10.65 mm). In the operation, the screw insertion in the fixation of the sagittal fracture was performed under the guidance of navigation system according to the presurgical planning. The postoperative CT scan showed exact reduction and fixation of the sagittal fracture in all cases. Computer-assisted navigation is a useful tool for the lag screw insertion in the precise fixation of sagittal fracture at the temporal root of the zygomatic arch in complex zygomaticomaxillary fractures.

Current concepts and future perspectives in computer-assisted navigated total knee replacement.

Total knee replacements (TKR) aim to restore stability of the tibiofemoral and patella-femoral joints and provide relief of pain and improved quality of life for the patient. In recent years, computer-assisted navigation systems have been developed with the aim of reducing human error in joint alignment and improving patient outcomes. We examined the current body of evidence surrounding the use of navigation systems and discussed their current and future role in TKR. The current body of evidence shows that the use of computer navigation systems for TKR significantly reduces outliers in the mechanical axis and coronal prosthetic position. Also, navigation systems offer an objective assessment of soft tissue balancing that had previously not been available. Although these benefits represent a technical superiority to conventional TKR techniques, there is limited evidence to show long-term clinical benefit with the use of navigation systems, with only a small number of studies showing improvement in outcome scores at short-term follow-up. Because of the increased costs and operative time associated with their use as well as the emergence of more affordable and patient-specific technologies, it is unlikely for navigation systems to become more widely used in the near future. Whilst this technology helps surgeons to achieve improved component positioning, it is important to consider the clinical and functional implications, as well as the added costs and potential learning curve associated with adopting new technology.

Application of computer-assisted navigation systems in oral and maxillofacial surgery.

SummaryThe oral and maxillofacial region has a complicated anatomy with critical contiguous organs, including the brain, eyes, vital teeth, and complex networks of nerves and blood vessels. Therefore, advances in basic scientific research within the field of intraoperative oral and maxillofacial surgery have enabled the introduction of the features of these techniques into routine clinical practice to ensure safe and reliable surgery. A navigation system provides a useful guide for safer and more accurate complex in oral and maxillofacial surgery. The effectiveness of a navigation system for oral and maxillofacial surgery has been indicated by clinical applications in maxillofacial trauma surgery including complex midfacial fractures and orbital trauma reconstruction, foreign body removal, complex dentoalveolar surgery, skull base surgery including surgery of the temporomandibular joint (TMJ), and orthognathic surgery. However, some fundamental issues remain involving the mobility of the mandible and difficulty in updating images intraoperatively. This report presents an overview and feasible applications of available navigation systems with a focus on the clinical feasibility of the application of navigation systems in the field of oral and maxillofacial surgery and solutions to current problems.

Clinical analysis of adult spontaneous cerebrospinal fluid rhinorrhea

To discuss the clinical characteristics, diagnosis and treatment of adult spontaneous cerebrospinal fluid rhinorrhea (CSFR). A retrospective study was conducted on 18 patients of CSFR. Nasal secretion was collected for biochemical analysis. Imaging examination was done for identification of the bony defect in skull base. In all cases, the glucose concentration of nasal secretion were more than 1.7 mmol/L, and the β-2 transferrin detected by immunoelectrophoresis technique were positive. Twelve cases were found to have bony defect in skull base. For the rest 6 cases without bony defect, MRI findings of 6 cases showed sinusoidal effusion with similar signals to cerebrospinal fluid, thus predicting the location of the leak. Conservative treatment was successful in one case, and the other 17 patients underwent endoscopic sinus surgery with computer assisted navigation system (CANS). The results of all cases underwent surgery were successful by one time. No recurrence occured during the follow-up time (11 to 24 months). The incidence of adult CSFR is low, hence it is easily to be missed and misdiagnosed. The majority of CSFR patients are middle-aged and elderly obese women, often combined with hypertension, diabetes, moderate and severe osteoporosis due to no daily exercise habits. Correct medical history collection, reasonable preoperative examination and accurate preoperative localization of bony defect are essential for surgical repairment. CANS used during operation can enable surgeons to locate the site of leakage accurately and shorten the operation time.

A new mini-navigation tool allows accurate component placement during anterior total hip arthroplasty.

IntroductionComputer-assisted navigation systems have been explored in total hip arthroplasty (THA) to improve component positioning. While these systems traditionally rely on anterior pelvic plane registration, variances in soft tissue thickness overlying anatomical landmarks can lead to registration error, and the supine coronal plane has instead been proposed. The purpose of this study was to evaluate the accuracy of a novel navigation tool, using registration of the anterior pelvic plane or supine coronal plane during simulated anterior THA.MethodsMeasurements regarding the acetabular component position, and changes in leg length and offset were recorded. Benchtop phantoms and target measurement values commonly seen in surgery were used for analysis. Measurements for anteversion and inclination, and changes in leg length and offset were recorded by the navigation tool and compared with the known target value of the simulation. Pearson’s r assessed the relationship between the measurements of the device and the known target values.ResultsThe device accurately measured cup position and leg length measurements to within 1° and 1 mm of the known target values, respectively. Across all simulations, there was a strong, positive relationship between values obtained by the device and the known target values (r=0.99).ConclusionThe preliminary findings of this study suggest that the novel navigation tool tested is a potentially viable tool to improve the accuracy of component placement during THA using the anterior approach.

Computer-Assisted Planning, Simulation, and Navigation System for Periacetabular Osteotomy.

Periacetabular osteotomy (PAO) is an effective approach for surgical treatment of hip dysplasia in young adults. However, achieving an optimal acetabular reorientation during PAO is the most critical and challenging step. Routinely, the correct positioning of the acetabular fragment largely depends on the surgeon's experience and is done under fluoroscopy to provide the surgeon with continuous live x-ray guidance. Our developed system starts with a fully automatic detection of the acetabular rim, which allows for quantifying the acetabular 3D morphology with parameters such as acetabular orientation, femoral head extrusion index (EI), lateral center-edge (LCE) angle, and total and regional femoral head coverage (FHC) ratio for computer-assisted diagnosis, planning, and simulation of PAO. Intraoperative navigation is conducted to implement the preoperative plan. Two validation studies were conducted on four sawbone models to evaluate the efficacy of the system intraoperatively and postoperatively. By comparing the preoperatively planned situation with the intraoperatively achieved situation, average errors of 0.6° ± 0.3°, 0.3° ± 0.2°, and 1.1° ± 1.1° were found, respectively, along three motion directions (flexion/extension, abduction/adduction, and external rotation/internal rotation). In addition, by comparing the preoperatively planned situation with the postoperative results, average errors of 0.9° ± 0.3° and 0.9° ± 0.7° were found for inclination and anteversion, respectively.

NAVIGATED TOTAL KNEE ARTHROPLASTY FOR OSTEOARTHRITIS WITH EXTRA-ARTICULAR DEFORMITY.

ABSTRACTObjective It is difficult to achieve proper alignment after total knee arthroplasty (TKA) in patients with extra-articular deformity (EAD) because of altered anatomical axis and distorted landmarks. As of this writing, only case series have been reported with regard to the usefulness of computer-assisted navigation systems for TKA with EAD. This study therefore compared outcomes in TKA with EAD, with and without navigation.Methods Fourteen osteoarthritis patients with EAD due to previous fracture malunion or operations were assessed. Seven TKAs were performed with navigation (navigation group) and another 7 were performed without navigation (manual group). Clinical and radiographic outcomes were compared before and two years after surgery.Results The mean postoperative Knee Society function score was significantly higher in the navigation group. No significant difference was found in postoperative range of motion and Knee Society knee score. The rate of outliers in radiographic outcomes tended to be lower in the navigation group.Conclusion Better clinical outcomes were achieved in cases in which navigation was used. Computer-assisted navigation is useful in TKA for patients with EAD. Level of Evidence III; Case control study.

CAMISS Concept and Its Clinical Application.

This chapter intends to provide an overview of computer-assisted minimally invasive spine surgery (CAMISS) and its clinical application. Since minimally invasive spine surgery was first brought out, the concept of decreasing the damage to patient was soon become popular. However, without the proper surgical field, the spine surgery can be very dangerous. The minimally invasive concept was restricted in promotion until the computer-assisted navigation system break down the obstacles. The CAMISS technique achieves better clinical outcomes with the advantages of smaller invasion, less injury, and better recovery and also became the gold standard for spine surgery. The spatial distribution concept and the respiration-induced motion concept help in promoting the accuracy and safety of the CAMISS concept. The CAMISS concept also facilitated the developing of robotic techniques, which was considered as the future of orthopedic surgery.

Computer-assisted navigation for intramedullary nail fixation of intertrochanteric femur fractures: A randomized, controlled trial

IntroductionLag screw cutout is one of the most commonly reported complications following intramedullary nail fixation of intertrochanteric femur fractures. However, its occurrence can be minimized by a well-positioned implant, with a short Tip-to-Apex Distance (TAD). Computer-assisted navigation systems provide surgeons with the ability to track screw placement in real-time. This could allow for improved lag screw placement and potentially reduce radiation exposure to the patient and surgeon. MethodsBetween Oct 2014 and Jan 2016, patients with intertrochanteric femur fractures being treated with intramedullary nail fixation by one of three fellowship-trained orthopaedic traumatologists were enrolled. Inclusion criteria were low-energy mechanism of injury and fracture class 31-A1/A2. Open fractures and patients with multiple injuries to the lower extremity were excluded. Patients were randomly assigned to computer-assisted navigation or a conventional fluoroscopic technique for lag screw placement. The primary outcomes were TAD, measured by postoperative anteroposterior and lateral x-rays by an independent reviewer, and radiation exposure measured in seconds of fluoroscopy time. Surgical time was also recorded. Results50 patients were randomized, 26 to the computer-assisted navigation group and 24 to the control group. The mean manually-measured TAD in the computer-assisted navigation group was 14.1mm±3.2 and in the control group was 14.9mm±3.0 (p=0.394). There was no difference between groups in total radiation time (navigation: 58.8 s±23.6, control: 56.5 s±28.5, p=0.337) or radiation time during lag screw placement (navigation: 19.4 s±8.8, control: 18.8 s±8.0, p=0.522). The surgical time was significantly longer in the computer-assisted navigation group with a mean surgical time of 45.8min±9.8 compared to 38.4min±9.3 in the control group (p=0.009). ConclusionsComputer-assisted navigation consistently produced excellent TADs, however it was not significantly better than conventional methods when done by fellowship-trained orthopaedic traumatologists. Surgeons with a lower volume trauma practice could potentially benefit from computer-assisted navigation to obtain better TAD.

Advances in Computer-Aided Technology for Total Knee Arthroplasty.

Technology such as computer-assisted navigation systems, robotic-assisted systems, and patient-specific instrumentation has been increasingly explored during the past decade in an effort to optimize component alignment and improve clinical outcomes. Computer-assisted navigation accurately restores mechanical-axis alignment, but clinical outcome data are inconsistent. Computer-assisted navigation gap balancing has shown early promise in establishing mechanical-axis alignment with improved functional outcomes. Robotic-assisted systems more accurately restore component alignment when compared with computer-assisted navigation, but clinical outcomes have yet to be determined. Patient-specific instrumentation does not consistently improve alignment, accuracy, or patient outcomes. Studies demonstrating implant survivorship, cost-efficiency, and improved clinical outcomes and patient satisfaction are needed. [Orthopedics. 2017; 40(6):338-352.].

The value of computer-assisted navigation for bone reconstruction after tumor resection.

This study was designed to evaluate the use of computer-assisted navigation with computed tomography (CT) images for bone reconstruction after resection in malignant bone tumor treatment. Forty-five patients with malignant bone tumors were recruited for this study. CT scan images in a computer-assisted navigation system were used to assist during the osteotomy, the pairing with allografts, and the monitoring of the allograft and joint lines to perform joint reconstruction. Our results show that osteotomy and allograft pairing were successful in all patients. The average duration of the osteotomy procedures was 46.8±12.3 min; and the average pairing time was 32.5±9.8 min. The anatomical registration points and the three-dimensional virtual CT images were successfully matched. The average error of registration was 0.36±0.09 mm. Also, the range of tumor resection and allograft osteotomy were successfully paired, with an average error of 0.11±0.03 mm. No complications such as unequal limbs length or joint deformities occurred after reconstruction. The average follow-up time was 11.6±3.9 months. The tumor recurrence rate was 11.1% (5/45) and the survival rate 95.6% (43/45). The average healing time for the allograft and host bone was 5.5±1.2 months and no unexpected internal fixations, fractures or joint collapses occurred. The average knee joint functionality MSTS score was 25.5±6.6 points. No significant differences were found in the length of tumor resection, rate of negative incision margin, duration of osteotomy or of pairing, registration error or allogeneic bone and defect matching error averages between those patients with tumor recurrence and those without it (p>0.05). Based on our results, the computer-assisted navigation system for bone reconstruction after malignant tumor resection allows for high precision during osteotomy, delivers a high success rate of pairing, results in great limb function and low complication rates, and is thus a highly successful and safe approach benefiting bone cancer patients.

Computer-assisted Minimally Invasive Transforaminal Lumbar Interbody Fusion May Be Better Than Open Surgery for Treating Degenerative Lumbar Disease.

This study was a retrospective review of prospectively collected clinical data. To evaluate the clinical and radiologic outcomes of computer-assisted minimally invasive spine surgery transforaminal lumbar interbody fusion (CAMISS-TLIF) and open TLIF for the treatment of 1-level degenerative lumbar disease. Minimally invasive TLIF is becoming increasingly popular; however, the limited space and high rate of hardware complications associated with this method are challenging to surgeons. Computer-assisted navigation has the potential to dynamically show the fine anatomic structures, which could theoretically facilitate minimally invasive spine procedures. Sixty-one patients underwent 1-level TLIF procedures (30, CAMISS-TLIF; 31, open TLIF). The computer-assisted navigation system was used for CAMISS-TLIF, whereas conventional fluoroscopy was used for open TLIF. Demographic, operative, visual analog scale, and Oswestry disability index data were collected. Screw insertion was assessed by computed tomography, and radiologic fusion based on Bridwell grading was evaluated 2 years after surgery by independent investigators. The CAMISS-TLIF group had significantly less blood loss, postoperative drain, need for transfusion, and initial postoperative back pain; earlier rehabilitation; and shorter postoperative hospitalization than the open TLIF group, whereas CAMISS-TLIF took longer surgical time than open TLIF. However, no significant differences between the 2 groups in visual analog scale scores and Oswestry disability index were observed at 3 months, 1 year, and 2 years postoperatively. A total of 93.33% and 73.39% of screws in the CAMISS and open groups, respectively, had no pedicle perforation (P=0.016), and the fusion rate was similar in both groups (P=0.787). Computer-assisted navigation facilitated minimally invasive spine surgery-TLIF. CAMISS-TLIF was superior to open TLIF for treating 1-level degenerative lumbar disease, although it required longer operation time in the initial stage. CAMISS-TLIF showed several benefits compared with open TLIF, including less intraoperative blood loss, postoperative drainage, and pain; earlier rehabilitation; and shorter postoperative hospitalization.