Computer-assisted Surgery Group Research Articles

Surgical accuracy of coronal and sagittal alignment in conventional closed-wedge high tibial osteotomy after computer-assisted surgery experience

BackgroundAlthough intraoperative navigation can improve the surgeon’s proficiency, no studies have analyzed postoperative outcomes of high tibial osteotomy (HTO) after computer-assisted surgery (CAS) experience. The present study compared the clinical and radiographic results between conventional and CAS closed-wedge (CW) HTOs after CAS experience.MethodsEach of the 50 conventional and CAS CW HTOs performed by single surgeon between 2015 and 2017 were included. The surgeon had experience of 140 cases of CAS CW HTOs before the study period. The groups were not different in terms of demographics. Clinically, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were investigated. Radiographically, the mechanical axis (MA), change in posterior tibial slope angle (PTS), and parallel angle were evaluated. The proportions of inlier groups for the postoperative MA (within valgus 2° ± 3°), change in the PTS (within ± 3°), and parallel angle (< 3°) were compared.ResultsThere were no significant differences in postoperative clinical results between the conventional and CAS groups. The MA was appropriately corrected in both groups (2.4° versus 2.9°, p = 0.317). The amount of change in PTS was significantly greater in the conventional group (−2.2° versus −0.8°, p = 0.018). The parallel angle was 5.3° in the conventional groups and 3.1° in the CAS group (p = 0.003). The proportion of inlier group was not significantly different in the postoperative MA (72% versus 78%) and change in the PTS (52% versus 66%). The proportion of inlier for the parallel angle was significantly lower in the conventional group (36% versus 60%, p = 0.027).ConclusionsThe surgical proficiency after CAS experience could cover the advantages of an intraoperative navigation in coronal adjustment, not in the sagittal adjustments in CW HTOs. A larger cohort with multiple surgeons in multiple centers would be required to identify the general trend.Study designLevel of evidence III.

Precision of the ultrasonography-integrated tibial extramedullary guide for total knee arthroplasty.

Precise determination of the tibial mechanical axis in total knee arthroplasty (TKA) requires intraoperative identification of the talus center. We present the ultrasonography-integrated tibial extramedullary guide (USG) that enables real-time visualization of the talus. This study assesses the precision of USG compared to computer-assisted surgery (CAS) and validates the efficacy of USG. We evaluated 58 patients (62 knees) who underwent primary TKA retrospectively, categorizing them into USG and CAS groups (31 each). We statistically analyzed demographic data, the preoperative alignment of the tibial plateau to the mechanical axis, the postoperative alignment of the tibial component to planned alignment on 3D-CT, pain visual analog scale, and WOMAC scores. Additionally, the frequency of postoperative outlier from planned alignment over 2° was statistically compared. No significant differences were observed in the preoperative data between the groups. The accuracy (mean deviation from the planned alignment) in both groups was not statistically different. However, in terms of the precision of coronal alignment, the USG group exhibited lower variance than the CAS group in the F-test (F value = 2.76, p = 0.023). Moreover, there were no postoperative deviations beyond 2 degrees in the USG group, in contrast to a 20% outlier frequency in the CAS group (p = 0.024). Concerning the precision of sagittal alignment (variance and deviations over 2°), no statistical differences were identified. The USG demonstrated higher precision in the tibial coronal plane than CAS in coronal alignment. Direct identification of the individual talus may enhance precision.

Application of a novel computer-assisted surgery system in percutaneous nephrolithotomy: A controlled study

BACKGROUNDMost complex renal stones are managed primarily with percutaneous nephrolithotomy (PCNL). However, PCNL is still a great challenge for surgeons because of poor comprehension on complex adjacent structures. Novel techniques are required to assist in planning and navigation.AIMTo apply and evaluate the Hisense computer-assisted surgery (CAS) system in PCNL.METHODSA total of 60 patients with complex renal stones were included. Thirty patients in the CAS group had three-dimensional (3D) virtual models constructed with the CAS system. The model assisted in planning and navigating in the CAS system. Thirty patients in the control group planned and navigated as standard PCNL, without the application of the CAS system. Success rate of one attempt, operation time, initial stone-free rate, decrease in hemoglobin, and complications were collected and analyzed.RESULTSThere were no statistically significant differences in the baseline characteristics or planning characteristics. The success rate of one puncturing attempt (90% vs 67%, P = 0.028) and the initial stone-free rate (87% vs 63%, P = 0.037) were significantly higher in the CAS group. However, there were no statistically significant differences in the operation time (89.20 ± 29.60 min vs 92.33 ± 33.08 min, P = 0.859) or in the decrease in hemoglobin (11.07 ± 8.32 g/L vs 9.03 ± 11.72 g/L, P = 0.300) between the CAS group and the control group. No statistically significant differences in the incidence of complications (Clavien-Dindo grade ≥ 2) were found.CONCLUSIONCompared with standard PCNL, CAS-assisted PCNL had advantages in terms of the puncturing success rate and stone-free rate. The Hisense CAS System was recommended to assist in preoperative planning and intraoperative navigation for an intuitive, precise and convenient PCNL.

Comparison of alignment between computer assisted surgery and personal specific instrumentation in total knee arthroplasty

Objective: To explore the differences of alignment and operative time between computer assisted surgery (CAS) and personal specific instrumentation (PSI) in total knee arthroplasty (TKA). Methods: Patients with knee osteoarthritis who underwent unilateral primary TKA in Peking University Third Hospital from June 2019 to April 2021 were enrolled in this prospective study and were randomly divided into CAS group and PSI group with random number table. The differences in preoperative general data, operative time, preoperative and postoperative alignment between the two groups were studied. Results: A total of 80 patients were enrolled in this study, including 40 patients in the CAS group with an average age of (68±6) years (male/female, 6/34 cases) and 40 patients in the PSI group with an average age of (69±6) years (male/female, 5/35 cases). There was no significant differences in gender, age, height, weight, body mass index, surgical side, preoperative hip-knee-ankle (HKA) angle, and preoperative HKA angle deviation between the two groups (all P>0.05). The accuracy of sagittal femoral component angle (sFCA) (1.7°±1.2° vs 2.5°±1.4°, P<0.05) and sagittal tibial component angle (sTCA) (1.2°±0.9° vs 2.3°±1.8°, P<0.01) of the CAS group were both smaller than those in the PSI group, but there was no significant difference in the accuracy of postoperative HKA angle, mechanical lateral distal femoral angle (mLDFA) and mechanical medial proximal tibia angle (mMPTA) between the two groups (all P>0.05). The precision of postoperative HKA angle and sTCA of the CAS group were both smaller than those in the PSI group (2.0°±1.0° vs 2.6°±1.7°, 1.2°±0.9° vs 2.3°±1.8°, both P<0.01), but there was no significant differences in the precision of mLDFA, mMPTA and sFCA between the two groups (all P>0.05). The rate of outliers of postoperative HKA angle (10.0% vs 27.5%, P<0.05), sFCA(5.0% vs 20.0%, P<0.05) and sTCA (2.5% vs 22.5%, P<0.01) of the CAS group were all smaller than those in the PSI group, but there was no significant difference in the rate of outliers of mLDFA and mMPTA between the two groups (both P>0.05). CAS group had significantly longer surgical time than the PSI group ((81±12) min vs (52±8) min, P<0.01). Conclusions: CAS is better than PSI in overall coronal alignment and sagittal position of the prosthesis after TKA. However, CAS requires a longer operation time.

Mandible reconstruction with free fibula flaps: Accuracy of a cost-effective modified semicomputer-assisted surgery compared with computer-assisted surgery - A retrospective study

A new individualized, cost-effective, modified semi-computer-assisted surgery (MSCAS) concept for free fibular flap mandibular reconstruction is reported and compared with the computer-assisted surgery (CAS) concept.Patients were divided into two groups and retrospectively reviewed. In the MSCAS and CAS groups, intraoperative guides were created using computer-aided design with manual fabrication and computer-aided design and manufacturing, respectively. Differences in specific linear and angular parameters on pre- and postoperative computed tomography scans were calculated for morphometric comparison, and clinical parameters and efficiency were analysed. ResultsEighteen patients (CAS, 7; MSCAS, 11), were included. The morphometric comparison showed no significant differences between the groups. The mean deviation of the mandibular ramus length, body length, width 1 and width 2 was 0.82 ± 0.29 mm, 1.84 ± 0.43 mm, 1.89 ± 0.61 mm and 1.45 ± 0.61 mm in the CAS group versus 1.56 ± 0.54 mm, 1.72 ± 0.33 mm, 2.24 ± 0.55 mm and 2.36 ± 0.50 mm in the MSCAS group (p = 0.7804, p = 0.9997, p = 0.9814 and p = 0.6334). The mean deviation of the sagittal, axial and coronal mandibular angles was 1.56 ± 0.48°, 1.93 ± 0.50° and 2.15 ± 0.72° in the CAS group versus 2.19 ± 0.35°, 1.86 ± 0.35° and 1.94 ± 0.55° in the MSCAS group (p = 0.7594, p = 0.9996 and p = 0.9871). There were no significant differences in clinical parameters, efficiency or postoperative complications between the groups. ConclusionThe accuracy and operative efficiency of the MSCAS concept are comparable to those of the more expensive CAS concept. Therefore, in times of increasing clinical costs, this concept might be an adequate and inexpensive alternative to preoperative CAS.

Computer-assisted versus traditional freehand technique for mandibular reconstruction with free vascularized fibular flap: A matched-pair study

This study aimed to perform a surgery-related and patient-related outcome analysis of a case-matched series of patients treated with computer-assisted surgery (CAS) and traditional freehand surgery. A total of 153 patients who underwent mandibular reconstruction by VFF were included from Jan 1999 to Dec 2019. The mandibular resection and reconstruction were performed by four experienced oral and maxillofacial surgeons. Reasons for reconstruction were oncologic, osteoradionecrosis, trauma, and osteoporosis. All the patients were followed up postoperatively for at least 1 year. Eighteen pairs were formed with the matched cohort consisting of a total of 36 patients who underwent primary mandibular reconstruction without additional combined flaps. The surgery-related and patient-related continuous and categorical parameters were assessed in both groups. The average operation time and bleeding volume in the CAS group were less than those in the non-CAS group. Additionally, both hospitalization and ICU days were lower in the CAS group without any significant difference. The only significant finding related to surgical parameters was observed for the ischemia time, which was lower in the CAS group. Computer-assisted surgery indicated improved efficiency considering reduced ischemia time, operation time, and length of hospital stay with lower early complications than that of conventional surgical procedures. It can thus be considered as an optimized alternative to the freehand approach.

Does the Use of Computer-Assisted Surgery Affect the Margin Status in Resections of Ameloblastoma?

Computer-assisted surgery (CAS) was implemented rapidly, and recent concerns have been raised regarding its safety and its effect on surgical outcomes. We wanted to understand the impact CAS has on the surgical margin status when used for the resection of ameloblastoma. We performed a 10-year retrospective cohort study at a single institution. Subjects were identified by surgical logs and chart query. Histopathologic reports were examined for margin status. We compared surgical technique (CAS and non-CAS) with the surgical margin (≤5mm vs >5mm). Other variable outcomes included previous treatment, histologic type, time from imaging to surgery, and recurrence. Bivariate analysis was performed to determine significance. A total of 31 subjects were identified (12 females; 19 males) with a mean age of 34.5 (standard deviation [SD] ± 19.1) years. Fifteen subjects were included in the CAS group and 16 subjects in the non-CAS group. No statistically significant difference was identified between the CAS and non-CAS group when surgical margins were defined as less than or equal to 5mm and greater than 5mm (P=.5368). The average distance from surgical margin to lesion was 9.6mm (SD ± 5.1) in the CAS group and 8.5mm (SD ± 5.6) in the non-CAS group (P=.2590). However, the non-CAS group had 1 positive margin and a total of 6 margins of less than or equal to 2mm compared with zero margins of less than or equal to 2mm in the CAS group (closest margin 3mm). The use of CAS and cutting guides based on predetermined surgical margins did not compromise the margin status in surgical resections of ameloblastoma. The use of CAS could potentially decrease the occurrence of close or positive margins.

CAS and PSI increase coronal alignment accuracy and reduce outliers when compared to traditional technique of medial open wedge high tibial osteotomy: a meta-analysis.

Medial open-wedge high tibial osteotomy (MOWHTO) is an accepted option in the treatment of medial compartment osteoarthritis of the knee in young and active patients. Functional results are closely correlated to the correction of the mechanical axis of the lower limb. Although several angular and geometrical methods and values have been proposed in the past, the ideal target is still debated. In addition, it is important to have a deep correlation between the planned correction and the achieved correction after surgery. The aim of the present systematic review was to identify the ideal coronal correction after MOWHTO and the most accurate method to achieve it. A systematic review of the literature was completed on July 3rd 2020 in the Pubmed, Medline, Cochrane Reviews, and Google Scholar databases using the Medical Subject Headings (MeSH) terms: "high tibial osteotomy" AND "accuracy" OR "planning". 28 studies were included; 18 were focused on computer-assisted surgery (CAS) and 10 on patient-specific instrumentation (PSI). There were 598 patients in the CAS group and 501 in the control group; the rate of outliers was 16% and 38.2% respectively (P = 0.04), while there was no significant difference between the two groups (SMD = - 0.10; 95% CI 1.31 to 1.12; P = n.s.) in terms of coronal accuracy. Likewise, there were 318 patients in the PSI group and 40 in the control group; the rate of outliers was 15% and 40% respectively (P = 0.98), while there was no significant difference between the two groups (SMD = 0.01; 95% CI 0.58 to 0.59; P = 0.98). A statistically significant reduced outlier rate and a non-significant increased accuracy emerged with the use of CAS when compared to the traditional surgical technique, whereas the results of PSI were still inconclusive. In addition, it emerged clearly that no consensus still exists on the ideal correction target to be achieved after surgery. III.

Do predetermined surgical margins compromise oncological safety in computer-assisted head and neck reconstruction?

Computer assisted head and neck reconstruction has gained popularity over the past few years. In computer assisted surgery (CAS), surgical margins are predetermined in virtual surgery and resection guides are designed to be fitted intra-operatively. However, concerns have been raised regarding the oncological safety of predetermined surgical margins. Therefore, the aim of this study was to compare surgical margins, recurrence and survival outcomes in patients underwent CAS and non-CAS in head and neck reconstruction. We retrospectively reviewed the patients underwent oral and maxillofacial malignancies surgical excision and free flap reconstruction from October 2014 to December 2019 by the same chief surgeon. Patients were divided into two groups depending on whether CAS and predetermined surgical margins were adopted. The primary outcome was surgical resection margin and the secondary outcomes included recurrence and survival. A total of 66 subjects were recruited with 37 in the CAS group and 29 in the non-CAS group. The follow-up rate was 100%. The average follow-up time was 24.5months. No significant difference in resection margin was identified between the groups (p=0.387). Tumor staging, margin status, perineural invasion, lymphovascular invasion and extranodal extension were identified as significant factors influencing survival. Both before and after adjustment for these prognostic factors identified, CAS and non-CAS group showed no significant difference in survival outcome. Predetermined surgical margins do not compromise oncological safety in terms of resection margin, disease recurrence and patient survival.

Time matters – Differences between computer-assisted surgery and conventional planning in cranio-maxillofacial surgery: A systematic review and meta-analysis

The aim of the study was to assess if there is a time difference (operative time, ischemia time, planning time and hospitalization) between computer-assisted surgery (CAS) and conventional planning in cranio-maxillofacial surgery. An electronic search was performed in June 2018. Studies comparing time difference between CAS and traditional planning were included. 28 publications were included, with 536 patients in the CAS group and 784 in the control group. 18 studies reported on mandibular/maxillary reconstruction and a meta-analysis was conducted on 15 of these studies. This meta-analysis was undertaken to demonstrate the difference between the groups regarding operative time, ischemia time and hospitalization for mandibular/maxillary reconstruction and showed a decreased operative time for the CAS group with a mean difference of −84.61 min, 95% confidence interval [−106.77, −62,45], p < 0.001. Ischemia time was also decreased, with a mean difference of −36.14 min, 95% confidence interval [−50.57, −21.71], p < 0.001. This systematic review and meta-analysis suggests that CAS is shortening the operative time and ischemia time for mandibular/maxillary reconstruction. It also leads to a reduction in hospitalization. Additionally, CAS seems to shorten the preoperative planning time for orthognathic surgery.

Use of Hisense Computer-Assisted Surgery System Enhances Infrapyloric Lymph Node Dissection for Gastric Cancer

BackgroundThis study aimed to establish a three-dimensional model of infrapyloric vessels using the Hisense computer-assisted surgery (CAS) system before the operation to understand blood vessel variation types and determine the group 6 lymph node (LN) metastasis status. MethodsOne hundred and four gastric cancer patients were randomly assigned to a CAS group and a computed tomography (CT) group. Intraoperative and postoperative complications in the two groups were recorded. The number of group 6 LNs dissected and the metastasis status were compared between the groups. The independent risk factors influencing group 6 LN metastasis were determined by multiple logistic regression analysis. ResultsIn the 50 CAS group patients, the gastrocolic trunk of Henle was divided into a gastrocolic type (34.0%) and a gastropancreatic colonic type (66.0%); the right gastroepiploic artery was divided into a coarse blood supply type (24.0%) and a fine blood supply type (76.0%); and the relationship between the right gastroepiploic artery and right gastroepiploic vein was divided into an adjacent type (58.0%) and a separated type (42.0%). Although the difference was not significant, the CAS group had fewer cases of intraoperative gastrocolic trunk injury and postoperative pancreatic leakage in trend than the CT group. The CAS group had more dissected LNs (P < 0.001) and metastatic LNs (P = 0.011) than the CT group; meanwhile, it had higher LN metastasis rate and LN metastasis degree in trend than the CT group. According to the multiple logistic regression model, tumor location and TNM stage were significantly correlated with group 6 LN metastases. ConclusionsBy establishing a three-dimensional model of the infrapyloric vessels using the Hisense CAS system, we comprehensively determined the anatomic variations in each collateral vessel. The application of the Hisense CAS system significantly improved the number of LNs dissected and the discovery rate of LN metastases without increasing the incidence of complications.

No Benefit of Computer-assisted TKA: 10-year Results of a Prospective Randomized Study.

Previously published studies reported benefits of computer-assisted surgery (CAS) in terms of radiographic implant position in TKA, but whether these improvements result in clinically important survival differences or functional differences that a patient might perceive at a minimum 10-year followup remains largely unknown. We performed a prospective randomized trial and asked whether CAS (1) improved survival free from aseptic loosening; and (2) demonstrated any clear difference in patient-reported outcomes at latest followup using validated outcome measures at minimum 10-year followup. Between January 2004 and December 2005, 80 patients scheduled for TKA were randomly assigned either to the CAS group or to the conventional technique group by the Hospital Informatics Department. The patient inclusion criteria were age 20 to 80 years old, weight < 100 kg, and consent to receive a primary knee arthroplasty performed through a medial parapatellar approach by the senior author. The exclusion criteria were a history of prior knee surgery, TKA performed for a posttraumatic indication, or revision knee surgery. The first 80 patients meeting these criteria were included in the study. There were 21 women and 19 men and in each group; mean age was 66 years (range, 58-77 years), and mean body mass index was 27 ± 4 kg/m. An initial published study using this patient group investigated only differences regarding implant positioning in the coronal and sagittal planes. This is a secondary analysis of patients from the earlier study protocol at a minimum of 10-year followup with different endpoints. Kaplan-Meier survivorship was compared between groups, and functional patient-reported outcome measures (PROMs) were evaluated using the SF-12, Knee Injury and Osteoarthritis Outcome Score (KOOS), Forgotten Joint Score, and the new Knee Society Score. Those PROMs were not available at the time of the original randomized controlled trial and we therefore do not have baseline preoperative values demonstrating that our two groups were comparable. However, our groups were created using strict randomization and were similar in terms of demographic parameters and knee deformities. Our secondary analysis was not powered for survival analysis but had 80% power to detect a difference > 6 points on the SF-12 components and > 6 points out of 100 on the KOOS subscores (published minimal clinically important difference: 8 points) at the p < 0.05 level. With the numbers available, there was no difference between the CAS group and the conventional TKA group in terms of survivorship free from aseptic loosening 10 years after TKA (97%, 95% confidence interval [CI], 95%-99% versus 97%, 95% CI, 95%-99%; p = 0.98). Investigation of the latest followup PROM scores showed no difference between SF-12 scores (respectively, for CAS and control patients, physical SF-12: 72 ± 12 versus 73 ± 13 mean difference 0, 95% CI -3 to 3, p = 0.9; mental SF-12: 75 ± 8 versus 73 ± 10, mean difference 2, 95% CI 0-4, p = 0.3) as well as for all KOOS subscores (all p > 0.1). Forgotten Joint Scores were similar in both groups with 83 ± 4 for CAS and 82 ± 5 for control patients (mean difference 1, 95% CI 0-2, p = 0.2). Finally, the new Knee Society Scores were not statistically different between groups with a mean objective score of 82 ± 13 for CAS patients versus 79 ± 12 for control patients (mean difference 2, 95% CI 0-5, p = 0.5) and a mean subjective score of 83 ± 11 versus 85 ± 12, respectively (mean difference 2, 95% CI 0-5, p = 0.5). Our observations suggest that CAS used for TKA alignment with restoration of a neutral mechanical axis as the goal did not confer any substantial advantage in survivorship, function, or quality of life at 10 years after TKA. Larger studies with longitudinal collection of PROMs for functional assessment and greater numbers to assess survivorship are needed to confirm these findings. Level III, therapeutic study.

Accelerometer-Based and Computer-Assisted Navigation in Total Knee Arthroplasty: A Reduction in Mechanical Axis Outliers Does Not Lead to Improvement in Functional Outcomes or Quality of Life When Compared to Conventional Total Knee Arthroplasty

BackgroundAccelerometer-based navigation (ABN) is a novel navigation system that attempts to combine the accuracy of computer-assisted surgery (CAS) with the familiarity of conventional instrumentation (CON). No studies have compared the clinical outcomes of this new technology with existing techniques to date. MethodsFrom July 2013 to April 2014, 152 consecutive patients (152 knees) underwent total knee arthroplasty using ABN (n = 38), CAS (n = 38), or CON (n = 76). We prospectively matched the groups in a 1:1:2 ratio for age, gender, body mass index, preoperative range of motion, Knee Society Score, Oxford Knee Score, Short-Form 36 Physical and Mental Component Scores, and preoperative deformity using preoperative data in isolation, thus controlling for potential confounding factors. All patients were prospectively followed for 2 years. ResultsThe ABN and CAS groups had a significantly improved mean mechanical axis (P = .018), femoral (P = .050) and tibial component alignment (P = .008) compared to the CON group. There were significantly less mechanical axis outliers in the ABN and CAS groups (P = .034). The duration of surgery for the ABN group (83.9 ± 21 min) was significantly shorter than the CAS group (101 ± 11 min; P < .001) but similar to the CON group (76.6 ± 17 min; P = .131). There was no significant difference in functional outcomes, quality of life measures or satisfaction rates between the 3 groups at 2 years (P > .05). ConclusionAlthough bone cuts were as accurate as CAS and operation time was similar to CON, the use of ABN failed to demonstrate any advantages in clinical outcomes following total knee arthroplasty at 2 years follow-up.

Use of Computer Assistance in Lumbar Fusion Surgery: Analysis of 15 222 Patients in the ACS-NSQIP Database.

Study Design:Retrospective cohort study.Objective:Several studies have shown that the accuracy of pedicle screw placement significantly improves with use of computer-assisted surgery (CAS). Yet few studies have compared the incidence of postoperative complications between CAS and conventional techniques. The objective of this study is to determine the difference in postoperative complication rates between CAS and conventional techniques in spine surgery.Methods:The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients who underwent posterior lumbar fusion from 2011 to 2013. Multivariate analysis was conducted to demonstrate the difference in postoperative complication rates between CAS and conventional techniques in spine surgery.Results:Out of 15 222 patients, 14 382 (95.1%) were operated with conventional techniques and 740 (4.90%) were operated with CAS. Multivariate analysis showed that patients in the CAS group had fewer odds to experience adverse events postoperatively (odds ratio [OR] = 0.57, P < .001). Minor adverse events occurred in 2905 (20.2%) patients in the conventional group and in 98 (13.2%) patients in the CAS group (OR = 0.57, P < .001). Blood transfusion was present in 2488 (17.3%) of the patients in the conventional group compared to 81 (11.0%) of the patients in the CAS group (OR = 0.56, P < .001). The mean operative time in the conventional group was 205.2 ± 106.1 minutes, and it was 227.0 ± 111.9 minutes in the CAS group. This difference was statistically significant (r = 20.14, P < .001).Conclusion:This article examined the complications in lumbar spinal surgery with or without the use of CAS. These results suggest that CAS may provide a safer technique for implant placement in lumbar fusion surgeries.

Similar migration in computer-assisted and conventional total knee arthroplasty

Background and purpose — Computer-assisted surgery (CAS) in total knee arthroplasty (TKA) has been used in recent years in the hope of improving the alignment and positioning of the implant, thereby achieving a better functional outcome and durability. However, the role of computer navigation in TKA is still under debate. We used radiostereometric analysis (RSA) in a randomized controlled trial (RCT) to determine whether there are any differences in migration of the tibial component between CAS- and conventionally (CONV-) operated TKA.Patients and methods — 54 patients (CAS, n = 26; CONV, n = 28) with a mean age of 67 (56–78) years and with osteoarthritis or arthritic disease of the knee were recruited from 4 hospitals during the period 2009–2011. To estimate the mechanical stability of the tibial component, the patients were examined with RSA up to 24 months after operation. The following parameters representing tibial component micromotion were measured: 3-D vector of the prosthetic marker that moved the most, representing the magnitude of migration (maximum total point motion, MTPM); the largest negative value for y-translation (subsidence); the largest positive y-translation (lift-off); and prosthetic rotations. The precision of the RSA measurements was evaluated and migration in the 2 groups was compared.Results — Both groups had most migration within the first 3 months, but there was no statistically significant difference in the magnitude of the migration between the CAS group and the CONV group. From 3 to 24 months, the MTPM (in mm) was 0.058 and 0.103 (p = 0.1) for the CAS and CON groups, respectively, and the subsidence (in mm) was 0.005 and 0.011 (p = 0.3).Interpretation — Mean MTPM, subsidence, lift-off, and rotational movement of tibial trays were similar in CAS- and CONV-operated knees.

Computer-assisted versus traditional freehand technique in fibular free flap mandibular reconstruction: a morphological comparative study.

The purpose of the study was to compare the accuracy of computer-assisted surgery (CAS) and the traditional freehand technique for fibular free flap mandibular reconstruction as well as to evaluate the accuracy of the CAS planning. The medical records of 18 patients who underwent mandibular reconstruction with fibular free flap were reviewed. The CAS group (n=7) benefited from virtual surgical planning and custom patient-specific plates and surgical cutting guides. The Control group (n=11) was treated by conventional surgery. Morphometric comparison was done by calculating the differences in specific linear and angular parameters on pre- and postoperative CT-scans for both groups by using ProPlan CMF® software. Symmetry was also assessed by calculating the ratio of the affected versus the nonaffected side. In the CAS group, planned and postoperative CT-scans were compared to evaluate accuracy. The morphometric comparison showed no statistically significant differences between the groups except for the axial angle on the nonaffected side (mean difference 1.0° in the CAS group versus 2.9° in the Control group; p=0.03). Ratios of the affected side over the nonaffected side showed no differences between the two groups. In the CAS group, the accuracy assessment showed a mean distance deviation of 2.3mm for mandibular osteotomies and 1.9mm for fibular osteotomies. Our results indicated that CAS and the conventional freehand techniques were comparable in their ability to provide a satisfactory morphological fibular free flap mandibular reconstruction. Moreover, the accuracy of the CAS technique was within the range reported in the literature.

A Comparison of the Medium-Term Results of Total Knee Arthroplasty Using Computer-Assisted and Conventional Techniques to Treat Patients With Extraarticular Femoral Deformities

BackgroundWe compared the medium-term results of total knee arthroplasty (TKA) performed using computer-assisted surgery (CAS) and conventional techniques in patients with extraarticular femoral deformities. MethodsThe clinical and radiographic data of 40 knees (34 patients) with extraarticular femoral deformities that underwent consecutive CAS-TKA were compared with those of a control group that underwent conventional TKA (80 knees, 63 patients). No demographic data (in particular, the causes of the extraarticular deformities) differed between the two groups. The follow-up periods of the CAS and conventional TKA groups were 6.0 and 6.3 years, respectively. ResultsIn the CAS group, the average knee score increased from 48.2 to 89.6 at the final follow-up (P < .001); the average function score increased from 51.4 to 91.4. The range of motion averaged 105.5° preoperatively and 123.3° postoperatively. No significant differences were found in the knee score, function score, or range of motion after TKA between the 2 groups. The average preoperative mechanical axes were 18.1° varus in both groups. The average postoperative mechanical axis was 1.4° varus in the CAS group and 3.3° varus in the conventional TKA group (P = .001). The proportion of postoperatively aligned knees was 77.5% in the CAS group and 32.5% in the conventional group (P < .001). ConclusionAlthough the medium-term clinical results of TKA in extraarticular femoral deformities were satisfactory in both the CAS and conventional TKA groups, the former group exhibited more accurate postoperative coronal alignment. It was useful to employ navigation in patients with extraarticular deformities of various etiologies.

No Benefit After THA Performed With Computer-assisted Cup Placement: 10-year Results of a Randomized Controlled Study.

Computer-assisted surgery (CAS) for cup placement has been developed to improve the functional results and to reduce the dislocation rate and wear after total hip arthroplasty (THA). Previously published studies demonstrated radiographic benefits of CAS in terms of implant position, but whether these improvements result in clinically important differences that patients might perceive remains largely unknown. We hypothesized that THA performed with CAS would improve 10-year patient-reported outcomes measured by validated scoring tools, reduce acetabular polyethylene wear as measured using a validated radiological method, and increase survivorship. Sixty patients operated on for a THA between April 2004 and April 2005 were randomized into two groups using either the CAS technique or a conventional technique for cup placement. All patient candidates for a THA with the diagnosis of primary arthritis or avascular necrosis were eligible for the CAS procedure and randomly assigned to the CAS group by the Hospital Informatics Department with use of a systematic sampling method. The patients assigned to the freehand cup placement group were matched for sex, age within 5 years, pathological condition, operatively treated side, and body mass index within 3 points. All patients were operated on through an anterolateral approach (patient in the supine position) using cementless implants. In the CAS group, a specific surgical procedure using an imageless cup positioning computer-based navigation system was performed. There were 16 men and 14 women in each group; mean age was 62 years (range, 24-80 years), and mean body mass index was 25 ± 3 kg/m(2). No patient was lost to followup at 10 years, but five patients have died (two in the CAS group and three in the control group). At the 10-year followup, an independent observer blinded to the type of technique performed patients' evaluation. Cup positioning was evaluated postoperatively using a CT scan in the two groups with results previously published. At 10 years, we assessed subjective functional outcome and quality of life using validated questionnaires (SF-12, Harris hip score [HHS], Hip injury and Osteoarthritis Outcome Score). Wear rate was then evaluated on standardized radiographs using a previously validated semiautomated computer analogic measurement method (dual circle method). Complications and survivorship were compared between groups. With our available sample size, this study had 80% power to detect a difference of 4 points out of 100 on the HHS at the p < 0.05 level. With the numbers available, we found we found no differences between groups regarding HSS at last followup 95.3 ± 5.9 points (CAS group) versus 96.2 ± 4.5 points, a mean difference of 0.9 points (95% confidence interval [CI], -4.3 to 4.6; p = 0.6). There was no difference between the groups in terms of the mean (± SD) acetabular linear wear at 10 years. The mean wear was 0.71 ± 0.6 mm in the CAS group versus 0.77 ± 0.52 mm in the control group, a mean difference of 0.06 mm (95% CI, -0.1 to 0.2; p = 0.54). With the numbers available, there was no difference between the CAS group and the conventional THA groups in terms of survivorship free from aseptic loosening (100%; 95% CI, 100%-95%, versus 100%; 95% CI, 100%-94%; p = 0.3). Our observations suggest that CAS used for cup placement does not confer any substantial advantage in function, wear rate, or survivorship at 10 years after THA. Because CAS is associated with added costs and surgical time, future studies need to identify what clinically relevant advantages it offers, if any, to justify its continued use in THA. Level II, therapeutic study.

Complications with and without the Use of Computer-Assistance in Lumbar Fusion Surgery: Analysis of 15,222 Patients in ACS-NSQIP Database

Introduction The objective of this paper is to demonstrate the difference in post-operative complication rates between Computer-assisted surgery (CAS) and conventional techniques in spine surgery. Several studies have shown that the accuracy of pedicle screw placement significantly improves with use of CAS. Yet, few studies have compared the incidence of post-operative complications between CAS and conventional techniques. Material and Methods The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients that underwent posterior lumbar fusion from 2011 to 2013. Multivariate analysis was conducted to demonstrate the difference in post-operative complication rates between CAS and conventional techniques in spine surgery. Results Out of 15,222 patients, 14,382 (95.1%) were operated with conventional techniques and 740 (4.90%) were operated with CAS. Multivariate analysis showed that patients in the CAS group had less odds to experience adverse events post-operatively (OR 0.57, p &lt; 0.001). Minor adverse events occurred in 2905 (20.2%) patients in the conventional group and 98 (13.2%) patients in CAS group (OR=0.57, p &lt; 0.001). Blood transfusion was present in 2488 (17.3%) of the patients in the conventional group compared with 98 of the patients in CAS group (10.95%)(OR=0.56, p &lt; 0.001). The mean operative time in the conventional group was 205.2 ± 106.1 minutes, and 227.0 ± 111.9 minutes in the CAS group. This difference was statistically significant (r=20.14, p &lt; 0.001). Conclusion This paper examined the complications in lumbar spinal surgery with or without the use of CAS. These results suggest that CAS may provide a safer technique for implant placement in lumbar fusion surgeries.

Economic evaluation comparing intraoperative cone beam CT-based navigation and conventional fluoroscopy for the placement of spinal pedicle screws: a patient-level data cost-effectiveness analysis

Background ContextPedicle screws are routinely used in contemporary spinal surgery. Screw misplacement may be asymptomatic but is also correlated with potential adverse events. Computer-assisted surgery (CAS) has been associated with improved screw placement accuracy rates. However, this technology has substantial acquisition and maintenance costs. Despite its increasing usage, no rigorous full economic evaluation comparing this technology to current standard of care has been reported. PurposeMedical costs are exploding in an unsustainable way. Health economic theory requires that medical equipment costs be compared with expected benefits. To answer this question for computer-assisted spinal surgery, we present an economic evaluation looking specifically at symptomatic misplaced screws leading to reoperation secondary to neurologic deficits or biomechanical concerns. Study Design/SettingThe study design was an observational case-control study from prospectively collected data of consecutive patients treated with the aid of CAS (treatment group) compared with a matched historical cohort of patients treated with conventional fluoroscopy (control group). Patient SampleThe patient sample consisted of consecutive patients treated surgically at a quaternary academic center. Outcome MeasuresThe primary effectiveness measure studied was the number of reoperations for misplaced screws within 1 year of the index surgery. Secondary outcome measures included were total adverse event rate and postoperative computed tomography usage for pedicle screw examination. MethodsA patient-level data cost-effectiveness analysis from the hospital perspective was conducted to determine the value of a navigation system coupled with intraoperative 3-D imaging (O-arm Imaging and the StealthStation S7 Navigation Systems, Medtronic, Louisville, CO, USA) in adult spinal surgery. The capital costs for both alternatives were reported as equivalent annual costs based on the annuitization of capital expenditures method using a 3% discount rate and a 7-year amortization period. Annual maintenance costs were also added. Finally, reoperation costs using a micro-costing approach were calculated for both groups. An incremental cost-effectiveness ratio was calculated and reported as cost per reoperation avoided. Based on reoperation costs in Canada and in the United States, a minimal caseload was calculated for the more expensive alternative to be cost saving. Sensitivity analyses were also conducted. ResultsA total of 5,132 pedicle screws were inserted in 502 patients during the study period: 2,682 screws in 253 patients in the treatment group and 2,450 screws in 249 patients in the control group. Overall accuracy rates were 95.2% for the treatment group and 86.9% for the control group. Within 1 year post treatment, two patients (0.8%) required a revision surgery in the treatment group compared with 15 patients (6%) in the control group. An incremental cost-effectiveness ratio of $15,961 per reoperation avoided was calculated for the CAS group. Based on a reoperation cost of $12,618, this new technology becomes cost saving for centers performing more than 254 instrumented spinal procedures per year. ConclusionsComputer-assisted spinal surgery has the potential to reduce reoperation rates and thus to have serious cost-effectiveness and policy implications. High acquisition and maintenance costs of this technology can be offset by equally high reoperation costs. Our cost-effectiveness analysis showed that for high-volume centers with a similar case complexity to the studied population, this technology is economically justified.