Postoperative Computed Tomography Scans Research Articles

Lipoprotein(a) and High-Sensitivity C-Reactive Protein Compound the Risk of Hypoattenuating Leaflet Thickening After Transcatheter Aortic Valve Replacement.

The mechanism for hypoattenuating leaflet thickening (HALT) after transcatheter aortic valve replacement is still not well elucidated, and the role of Lp(a) (lipoprotein[a]) and hs-CRP (high-sensitivity C-reactive protein) has rarely been studied. This study sought to test the hypothesis that the risk of HALT is associated with an elevated level of Lp(a) or hs-CRP. A total of 307 consecutive individuals who underwent a transcatheter aortic valve replacement procedure were included. All patients received their first postoperative computed tomography scans within 12 months, and raw data were analyzed on 3mensio software. HALT was defined as visually identified increased leaflet thickness with typical meniscal appearance and at least 2 different multiplanar reformation projections. Associations of Lp(a) or hs-CRP with the risk of HALT were evaluated using multivariable logistic regression analysis. The incidence of HALT within 12 months after transcatheter aortic valve replacement in this study was 36.2%, and the risk of HALT was associated with higher baseline Lp(a) (the multivariable adjusted odds ratio [OR] for every 10 mg/dL change was 1.18 [95% CI, 1.09-1.29]) and hs-CRP level (the multivariable adjusted OR for every 1 mg/L change was 1.08 [95% CI, 1.00-1.27]). Compared with individuals out of the top 25th percentile for both Lp(a) and hs-CRP, the multivariable adjusted OR for HALT was 4.74 (95% CI, 1.65-14.37) for the top 25th percentile. This result remained consistent after excluding patients receiving anticoagulant therapy. The top 25th percentile of Lp(a) level (≥40 mg/dL) combined with the top 25th percentile of hs-CRP level (≥3.5 mg/L) conferred a 4.74-fold risk of HALT.

Does More Invasive Surgery Result in Higher Patient Satisfaction? A Long-Term Follow-Up of 136 Zygomaticomaxillary Complex Fractures

Study Design Retrospective with follow-up. Objective To evaluate the long-term satisfaction of surgically treated patients with zygomaticomaxillary complex (ZMC) fractures in relation to the use of internal fixation, number of fixation points, and orbital floor (OF) reconstruction. Secondary objectives were to describe the use of antibiotics and post-operative infections. Methods Patients with unilateral ZMC fractures between 2007-2018 and treatment with either open reduction and internal fixation (ORIF) or closed reduction (CR) were identified from medical records and invited to follow-ups between 2018-2020. Patients were examined, photographed, and completed a questionnaire. A review panel of 3 experienced surgeons evaluated photographs and computed tomography (CT) scans pre- and post-surgery. Results The study sample consisted of 136 patients (108 ORIF, 28 CR) with a median follow-up time of 76 months. Patient satisfaction of surgical outcome was high (97.8%), with no significant differences in relation to the use of internal fixation, number of fixation points, or OF reconstruction. Dissatisfaction was primarily related to hypoesthesia. On post-operative CT scans, malar asymmetry was more often predicted in patients with 1-point fixations. On questionnaires and photographs, malar asymmetry was more common in patients with 3-point fixations. Prophylactic antibiotics had no effect on the rate of post-operative infections. Conclusions Patient satisfaction was not influenced by internal fixation, number of fixation points, or OF reconstruction. Selected ZMC fractures can be treated with less invasive approaches. Caution should be observed when predicting long-term malar asymmetry on post-operative CT scans. The findings of this study highlight the importance of a rational and ethical use of surgery.

Intranasal Outer Cortex Splinting With a Kirschner Wire to Immobilize Reduced Buckle-out Segments in Nasal Fractures

High-velocity lateral impacts to the nose sometimes cause nasal buckle-out fractures with a trapdoor buckle-out segment displaced outwards. Prolonged immobilization of a reduced buckle-out segment at risk for outward redisplacement remains challenging. Here we introduce a novel method of intranasal outer cortex splinting with a Kirshner (K)-wire to reinforce the reduced state and prevent outward re-displacement of the buckle-out segment. Eighteen patients with nasal buckle-out fractures underwent outer cortex K-wire splinting to securely immobilize a reduced but unstable buckle-out segment after indirect open reduction through intercartilaginous incisions and inner cortex K-wire splinting. A thin K-wire (diameter 0.8 mm) was inserted at the vestibule, passed above the upper lateral cartilage and the outer cortex of the reduced buckle-out segment, and extended to the cephalic non-fractured bone. The wire served as a crossbeam, effectively supporting the reduced buckle-out segment. All K-wires for inner and outer cortex splinting were removed 10 to 14 days postoperatively. Immediate postoperative computed tomography scans showed successful immobilization of buckle-out segments in 17 patients (94.5%). Postoperative 6-month scans of 7 patients showed excellent maintenance and bony alignment of buckle-out segments in all cases. Sixteen patients (88.9%) were satisfied with the overall external nasal contour at the last follow-up. There were no complications directly related to outer cortex K-wire splinting. One patient complained of a focal lateral protrusion resulting from the under-correction of a buckle-out segment. This technique may be a valuable option for immobilizing and maintaining reduced nasal buckle-out segments until a stable bony union is established.

Delayed Maxillary Reconstruction with Free Osteocutaneous Fibula Flap Using CAD-CAM Technology

Abstract Background Maxillary reconstruction poses unique challenges for the reconstructive surgeon because of the complex three-dimensional (3D) anatomy of the maxilla. Undertaking this endeavor on secondary reconstruction makes it more difficult due to problems in recreating the true defect. This study is an attempt to demonstrate the role of virtual surgical planning (VSP), 3D printing, and mock surgery in reconstructing such defects using free fibula flaps. Materials and Methods This was a prospective study involving 10 patients of maxillary defects who underwent delayed reconstruction with a free fibula flap. The planning was done preoperatively using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. A mock surgery with 3D printed models was done before the surgery. After the surgery, the accuracy results were obtained by overlapping and measuring fixed point distances between preoperative virtual planning and postoperative computed tomography (CT) scan data. Results and Discussion Nine patients underwent successful reconstruction and were satisfied with the outcome. One patient had flap loss. The mean shift along the horizontal, vertical, and 3D axes was less than 5 mm between the preoperative virtual planning and postoperative CT scan data, indicating accurate reconstruction. We also suggest strategies for soft-tissue and bony inset including inferolateral pedicle origin, anteriorly facing lateral fibular surface, and two bony struts for the alveolus. Conclusion VSP and CAD-CAM technology in maxillary reconstructions help achieve an anatomically accurate neo-maxilla. The addition of mock surgery to the routine and the use of cutting guide avoid unpredictability and reduce the need for adaptation activities on the operating table. CAD-CAM technology despite its limitations is invaluable in maxillary reconstruction and is an important tool for a reconstructive plastic surgeon.

Accelerometer-based portable navigation system shows no superior accuracy over pelvic alignment guide for acetabular cup placement in total hip arthroplasty in lateral decubitus position.

Total hip arthroplasty (THA) using a portable navigation system (PNS) incurs costs per procedure. However, it does not require a large console. This study aimed to compare the accuracy of acetabular cup placement using a pelvic alignment guide (PAG) attached to the pelvis and an accelerometer-based PNS in THA performed in the lateral decubitus position. We retrospectively analyzed 100 hips that underwent primary THA in the lateral decubitus position between July 2018 and January 2021. The PAG was used in 50 hips, whereas the PNS was used in the other 50. Cup placement accuracy was measured using postoperative computed tomography scans, comparing errors in inclination and anteversion angles. The surgical time, blood loss, and complications were recorded. The follow-up period was at least 2 years in all cases. The mean absolute error of the inclination angle was similar between the groups (the PAG group: 3.7° ± 2.3° [range, 0.0-9.0]; the PNS group: 3.7° ± 2.3° [range, 0.2-10.5], p = 0.705). The mean absolute error of the anteversion angle was significantly smaller in the PAG group than in the PNS group (3.0° ± 2.4° [range, 0.0-9.7] vs. 6.5° ± 4.8° [range, 0.3-17.3], p < 0.001). The PAG group had a higher proportion of hips within 5° and 10° of the target angle (64 vs. 42%, P = 0.028, and 100 vs. 74%, p < 0.001, respectively). The PNS group had six hips with anteversion errors of 15° or more. Surgical time and blood loss were lower in the PAG group. The PNS group had one dislocation, whereas the PAG group did not. The accelerometer-based PNS did not demonstrate superior cup alignment accuracy compared to the PAG in THA performed in the lateral decubitus position. This finding informs surgeons that computer-assisted surgery is not necessarily superior to conventional THA using a PAG.

Risk factors for proximal and distal aortic events after type A acute aortic dissection.

Type A acute aortic dissection (TAAAD) is a life-threatening condition often requiring emergency surgery, with approximately 30% of patients needing reoperation. This study aimed to identify predictors of long-term aortic events from early postoperative computed tomography (CT) examinations. A total of 336 cases underwent TAAAD surgery at two institutions between 2002 and 2018. Of these, 302 patients received CT examinations immediately after initial TAAAD surgery. Predictors of aortic events were evaluated from these early postoperative CT exams. Aortic events were defined as any events involving aortic-related death, open surgery, reoperation, endovascular stenting, or thoracic aorta diameter enlargement to ≥ 55mm. Excluding 34 in-hospital deaths (10.1%; 34/336), the 1-, 5-, and 10-year actuarial survival rates after primary TAAAD surgery were 98.2%, 88.6%, and 81.7%, respectively. Over a mean follow-up period of 7.4 ± 5.1years, 67 aortic events (proximal: 19, distal: 45, both: 3) were observed. Freedom from proximal aortic events was 98.6%, 93.9%, and 85.2% at 1, 5, and 10years, respectively. Proximal anastomosis new entry was identified as a significant risk factor for aortic events, with a 92% vs. 42% incidence at 10years (p < 0.001). Freedom from distal aortic events was 99.6%, 84.5%, and 67.2% at 1, 5, and 10years, respectively. A false/true area ratio greater than 1 and distal anastomosis new entry were significant risk factors for aortic events (low-risk group: 83.3% vs. high-risk group: 42.3% at 10years, p < 0.001). Detailed analysis of early postoperative CT scans following primary TAAAD surgery may help identify predictors of subsequent aortic events, potentially improving long-term patient management and outcomes.

Assessing adequacy of surgical extent in CRSwNP: The Completion of Surgery Index.

Endoscopic sinus surgery (ESS) maximized for topical steroid irrigations is highly effective for polyp disease. As extent and completeness of ESS varies widely by situation and practitioner, it is important to understand when revision surgery is appropriate, particularly in the era of biologic treatments. A Completion of Surgery Index (CoSI) was developed to assess operative changes in polyp patients using pre- and postoperative computed tomography scans. The CoSI was then applied and tested in a cohort of consecutive chronic rhinosinusitis with nasal polyps (CRSwNP) patients, and examined within the context of quality-of-life improvements. The CoSI assesses surgical extent on a scale of 0-100, with 100 representing the highest possible degree of surgical completeness. Among 100 consecutive CRSwNP patients undergoing ESS in 2021 with postoperative topical steroid irrigations, including 75 revision surgeries, SNOT-22 scores improved at 6months postoperatively, with durable and consistent improvement at 24months (p<0.001). Preoperative CoSI scores in revision surgery patients were 49.4±26.0, improving to 91.0±8.1 postoperatively. SNOT-22 scores for primary ESS patients and patients with a preoperative CoSI score of less than 70 improved by 26.4 and 28.1 points, respectively, in contrast to patients with a preoperative CoSI of 70 or greater (14.1 points, p=0.029). It is important to define extent of surgery in CRSwNP to stratify postsurgical patients based on likelihood to benefit from revision surgery or alternative medications. The CoSI can be utilized to identify patients who are likely to improve significantly with revision surgical intervention.

Functional preoperative assessment of coronal knee laxity better predicts postoperative patient outcomes than intraoperative surgeon-defined laxity in total knee arthroplasty.

Intraoperative laxity assessments in total knee arthroplasty (TKA) are subjective, with few studies comparing against standardised preoperative and postoperative assessments. This study compares coronal knee laxity in TKA patients awake and anaesthetised, preprosthesis and postprosthesis implantation, evaluating relationships to patient-reported outcome measures. A retrospective analysis of 49 TKA joints included preoperative and postoperative computed tomography scans, stress radiographsand knee injury and osteoarthritis outcome score (KOOS) questionnaire results preoperatively and 12 months postoperatively. The imaging was used to assess functional laxity (FL) in awake patients, whereas computer navigation measured intraoperative surgical laxity (SL) preimplantation and postimplantation, with patients anaesthetised. Varus and valgus stress states and their difference, joint laxity, were measured. SL was greater than FL in both preimplantation [8.1° (interquartile range, IQR2.0°) and 3.8° (IQR 2.9°), respectively] and postimplantation [3.5° (IQR 2.3°) and 2.5° (IQR 2.7°), respectively]. Preimplantation, SL was more likely than FL to categorise knees as correctable to ±3° of the mechanical axis. Preoperative FL correlated with KOOS Symptoms (r = 0.33, p = .02) and quality of life (QOL) (r = 0.38, p = .01), whereas reducing medial laxity with TKA enhanced postoperative QOL outcomes (p = .02). Functional coronal knee laxity assessment of awake patients is generally lower than intraoperative surgical assessments of anaesthetised patients. Preoperative SL may result in overcorrection of coronal TKA alignment, whereas preoperative FL better predicts postoperative patient outcomes and reflects the patients' native and tolerable knee laxity. Preoperative FL assessment can be used to guide surgical planning. Level II.

Clinical and radiological outcome of extended lateral approach via epicondyle osteotomy in complex lateral tibia plateau fractures involving the central and postero-lateral segments

IntroductionThe purpose of this study was to evaluate the clinical and radiological results of complex lateral tibial plateau fractures involving the central segments of the lateral tibial plateau. It was hypothesized that an extended lateral approach by using the lateral epicondyle osteotomy improves the rate of malreduction and yields to good and excellent clinical results at a mid-term follow-up. MethodsThis retrospective case series conducted at two centers evaluated complex lateral tibial plateau fractures treated with an extended lateral approach by lateral epicondyle osteotomy. Fractures were classified according to the AO/OTA and 10-segment classification, with only B/C type fractures involving the antero-latero-central (ALC) and postero-latero-central (PLC)/postero-latero-lateral (PLL) segments. Postoperative computer tomography scans were used to assess the quality of reduction. Clinical outcomes and postoperative complications were evaluated with a minimum follow-up of 2 years. ResultsSixty-five patients (mean age: 47.7 ± 11.5 years) were included, with an average follow-up of 51.9 ± 3.6 months. Radiological outcomes revealed a postoperative fracture step at the ALC/PLC crossing of 0.8 ± 1.1 mm, at the PLC/PLL crossing of 0.4 ± 1.1 mm, and a fracture gap of 1.8 ± 4.0 mm, yielding a Rasmussen Score of 15.1 ± 3.2. No significant differences among type B and C fractures were identified. No case of nonunion of the lateral epicondyle osteotomy was recorded. The mean Knee injury and Osteoarthritis Outcome Score was 80.4 ± 16.2 (type B 85.6 ± 11.9 vs. type C 76.1 ± 18.4, p < 0.05), Lysholm score was 83.4 ± 17.1 (B 89 ± 11.3 vs. C 78.7 ± 20.1, p < 0.05) and International Knee Documentation Committee score was 69.9 ± 18.8 (type B 76.5 ± 15.7 vs. type C 64.3 ± 20.1, p < 0.05). Early complication rate requiring surgical revision due to malreduction or infection were 7 %. None of the patients reported about subjective lateral knee instability at the time of clinical follow-up. ConclusionThe extended lateral approach with lateral epicondyle osteotomy demonstrated excellent radiological alignment and favorable mid-term clinical outcomes. An overall low complication rate was recorded. Notably, long-term revisions due to lateral instability were absent, indicating the safety and efficacy of lateral epicondyle osteotomy as an operative technique.

Clinical validation of artificial intelligence-based preoperative virtual reduction for Neer 3- or 4-part proximal humerus fractures

BackgroundIf reduction images of fractures can be provided in advance with artificial-intelligence (AI)-based technology, it can assist with preoperative surgical planning. Recently, we developed the AI-based preoperative virtual reduction model for orthopedic trauma, which can provide an automatic segmentation and reduction of fractured fragments. The purpose of this study was to validate a quality of reduction model of Neer 3- or 4-part proximal humerus fractures established by AI-based technology.MethodsTo develop the AI-based preoperative virtual reduction model, deep learning performed the segmentation of fracture fragments, and a Monte Carlo simulation completed the virtual reduction to determine the best model. A total of 20 pre/postoperative three-dimensional computed tomography (CT) scans of proximal humerus fracture were prepared. The preoperative CT scans were employed as the input of AI-based automated reduction (AI-R) to deduce the reduction models of fracture fragments, meanwhile, the manual reduction (MR) was conducted using the same CT images. Dice similarity coefficient (DSC) and intersection over union (IoU) between the reduction model from the AI-R/MR and postoperative CT scans were evaluated. Working times were compared between the two groups. Clinical validity agreement (CVA) and reduction quality score (RQS) were investigated for clinical validation outcomes by 20 orthopedic surgeons.ResultsThe mean DSC and IoU were better when using AI-R that when using MR (0.78 ± 0.13 vs. 0.69 ± 0.16, p < 0.001 and 0.65 ± 0.16 vs. 0.55 ± 0.18, p < 0.001, respectively). The working time of AI-R was, on average, 1.41% of that of MR. The mean CVA of all cases was 81%±14.7% (AI-R, 82.25%±14.27%; MR, 76.75%±14.17%, p = 0.06). The mean RQS was significantly higher when AI-R compared with MR was used (91.47 ± 1.12 vs. 89.30 ± 1.62, p = 0.045).ConclusionThe AI-based preoperative virtual reduction model showed good performance in the reduction model in proximal humerus fractures with faster working times. Beyond diagnosis, classification, and outcome prediction, the AI-based technology can change the paradigm of preoperative surgical planning in orthopedic surgery.Level of evidenceLevel IV.

Intraoperative computerised tomography scan for percutaneous fixation of the pelvis: a retrospective case series

PurposeFractures and dislocations of the pelvic ring are complex injuries that when treating require meticulous attention to detail and often specialized technical skill. These injuries can be the result of high-energy trauma, particularly in younger patients, or low energy trauma more often found in the elderly. Regardless of mechanism, these injuries lie on a spectrum of severity and can be treated conservatively or surgically. Percutaneous fixation under fluoroscopic guidance is the preferred standard technique when treating these fractures. This technique can be challenging for a variety of reasons including patient characteristics, intra-operative image quality, fracture morphology, among others.MethodsThis retrospective study evaluated the use of intra-operative computed tomography (CT) using an O-arm imaging system for critical evaluation of fluoroscopic-guided screw placement in twenty-three patients. We retrospectively reviewed all cases of patients who were treated by three fellowship-trained orthopaedic traumatologists during a one-year span. Patients undergoing percutaneous pelvis fixation using both standard fluoroscopy and intraoperative CT with the Medtronic O-arm® (Minneapolis, MN) imaging system. Additionally, procedures performed included open reduction internal fixation (ORIF) of the pelvic ring, acetabulum, and associated extremity fractures.ResultsTwenty-three patients were included in this study. On average, the use of intraoperative CT added 24.4 min in operative time. Five patients (21.7%) required implant adjustment after O-arm spin. Fourteen patients underwent additional post-operative CT. No secondary revision surgeries were attempted after any post-operative CT.ConclusionsOur study suggests that intra-operative CT scan, compared to post-operative CT scan, can be utilized to prevent take-back surgery for misplaced implants and allow for adjustment in real-time.

Early Bone and Suture Reformations in Different Cranial Regions After Cranial Vault Remodeling for Sagittal Craniosynostosis.

Cranial vault remodeling (CVR) is a common procedure for correcting sagittal craniosynostosis. Some approaches leave significant craniectomy defects. The authors investigated the reosteogenesis in different cranial defect areas after CVR. A cross-sectional study was conducted in nonsyndromic sagittal craniosynostosis. Available early postoperative computed tomography (CT) scans were analyzed. The segmentation of three-dimensional reconstructed images was performed. Different cranial defect areas, including coronal, vertex, and occipital regions, were further investigated using an automated three-dimensional analysis software for reosteogenesis percentage. Forty-four CT scans were included. The average age at CVR was 8.8 months. The median time of postoperative CT scans was 6.1 weeks. The median bone reformation percentage of the entire cranial defect was 56.7%. Given the similar postoperative CT timing, the median bone reformation at the coronal, vertex, and occipital areas demonstrated 44.21%, 41.13%, and 77.75%, respectively (P < 0.001). In the simultaneously removed coronal and lambdoid sutures, there were 45% with coronal and lambdoid sutures reformation, followed by lambdoid suture reformation alone, no suture reformation and coronal reformation alone in 35%, 20%, and 0%, respectively (P = 0.013). There was no coronal reformation in the removed coronal suture group. However, 40% demonstrated lambdoid suture reformation after the isolated lambdoid suture removal. The occipital region has the highest reosteogenesis compared with the other cranial defects after CVR in nonsyndromic sagittal craniosynostosis. Within the removed previous patent sutures, the lambdoid suture reformation showed a higher rate than the coronal suture.

Which type of supra-syndesmal fractures Weber C or Equivalent Weber C have the best reduction of the distal tibio-fibular syndesmosis? A prospective CT-scan investigation on 60 ankles

IntroductionThe reduction of the distal tibiofibular syndesmosis (SyTFd) is a crucial factor in the functional prognosis following a suprasyndesmotic ankle fracture. Few studies have compared, using computed tomography (CT), the quality of SyTFd reduction in Weber C ankle fractures (WebC) and Equivalent Weber C (EqWebC) fractures, where there is a medial ligament injury instead of a bony malleolar lesion. This CT-based study aimed to answer the following questions: (1) Do Weber C fractures allow for better reduction of the distal tibiofibular syndesmosis compared to Equivalent Weber C fractures? (2) Are the functional outcomes one year postoperatively better for Weber C fractures compared to Equivalent Weber C fractures? HypothesisThe hypothesis was that WebC fractures would present better reduction of the SyTFd than EqWebC fractures due to the restoration of bone anatomy, considering the bony nature of the medial ligament involvement. Materials and methodsSince December 2021, all patients presenting with an ankle fracture were included in a database. Suprasyndesmotic fractures were extracted, and between December 2021 and February 2022, 60 patients underwent surgery for a suprasyndesmotic fracture (28 WebC – 32 EqWebC). All patients were operated on using the same technique and underwent a postoperative bilateral CT scan in axial slices with both ankles in a neutral position (foot at 90 ° to the leg). An analysis of 8 measurements was performed under the same conditions. Each fractured ankle was compared to the healthy contralateral ankle, and a delta was obtained for each measurement. The follow-up was standardized. At one year, an AOFAS Score and a Maryland Foot Score (MFS) were recorded. Statistical differences between the two groups were measured using the Student's t-test and Chi-square test. ResultsThere was a significant difference between the WebC and EqWebC groups for clinical scores at one year postoperatively: AOFAS: 92.0 ± 6.3 [78–100] vs. 80.1 ± 5.4 [62–100], p < 0.05; MFS: 90.9 ± 6.4 [78–100] vs. 81.6 ± 5.2 [64–100], p < 0.05. CT scan analysis of the SyTFd reduction found significantly better reduction in the WebC group. DiscussionWebC fractures showed better clinical scores associated with better SyTFd reduction on postoperative CT scans. The anatomical reduction related to the bone reduction criteria during surgery could explain our findings. Level of evidenceIII; Case-Control Comparative Study.

Comparison of rostral facet joint violations in robotic- and navigation-assisted pedicle screw placement for adult lumbar spine instrumentation

BACKGROUND CONTEXTFacet joint violation by pedicle screws may lead to adjacent-segment disease and postoperative pain. Previous studies have reported the incidence of rostral facet joint violation using various pedicle screw insertion techniques. However, the incidence of facet joint violations with robotic guidance has not been determined. PURPOSETo investigate and compare the incidence of rostral facet joint violation by pedicle screws under robotic guidance and computerized tomography (CT) navigation guidance. STUDY DESIGN/SETTINGRetrospective matched cohort. PATIENT SAMPLEAll patients who underwent robotic-assisted lumbar fusion at a major spine center up until 2023 were retrospectively identified and matched 1:3 to patients undergoing CT navigation guidance based by on age, sex, rostral vertebral level, and length of construct. Inclusion criteria consisted of age greater than 18 years, bilateral pedicle screw fixation, and presence of a postoperative CT scan of the lumbar spine or abdomen/pelvis at any point in the post-operative period. OUTCOME MEASURESRostral facet joint violations. METHODSDescriptive statistics were used to compare cohorts: frequencies, chi-squared analysis for categorical variables, and t-test for continuous variables. RESULTSA total of 408 rostral pedicle screws were implanted in 204 patients (Robot: 102; Navigation: 306). Overall, 13 (12.3%) rostral facet joint violations were observed in the robot cohort and 75 (24.5%) in the navigation cohort (p=.01). Specifically, fewer robotic violations were observed at the L2 (3.5% vs. 32.1%, p=.003) and L3 levels (3.9% vs. 18.1%, p=.08) compared to navigation. No difference was observed at L4 and L5. Bilateral violations are significantly reduced with robotic approaches (5.3% vs. 14.4%, p=.03). Lastly, more facet joint violations were observed during open approaches (robot: 18.8%, navigation: 27.3%) than percutaneous approaches (robot: 11.6%, navigation: 7.1%) in both groups (p<.001). The rate of L4 facet violations was 18.8% in the robotic cohort and 27.3% in the navigation cohort. The rate of L5 facet violations was 31.3% in the robotic cohort and 29.2% in the navigation cohort. CONCLUSIONSUse of robotic assistance in lumbar pedicle screws significantly reduced the rate of rostral facet joint violations compared to navigation guidance at L2 and L3 levels, but not at L4 and L5, with facet violations approaching nearly one-third of the patients at L5 screws. Rostral facet violations can play a significant role in adjacent segment degeneration and disease. Technical factors and trajectory issues likely play a role and addressing these components should minimize unintended facet violation and proximal adding on.

Differential Impact of Subcutaneous and Visceral Fat on Bone Changes after Gastrectomy.

Osteoporosis and fragility fractures are crucial musculoskeletal complications in long-term survivors of gastric cancer. However, the relationship between changes in body composition after gastrectomy and bone loss has not been investigated. Therefore, this study aimed to explore whether computed tomography (CT)-derived body composition parameters are associated with bone loss after gastrectomy in patients with gastric cancer. We retrospectively reviewed medical records and abdomen CT scans of patients who underwent gastrectomy at Yonsei University Severance Hospital between 2009 and 2018. Patients with non-metastatic gastric adenocarcinoma and preoperative and postoperative non-contrast CT scans were analyzed. Section area of skeletal muscle (SMA), visceral fat (VFA), and subcutaneous fat (SFA) were assessed using semi-automatic segmentation software. Changes in trabecular bone attenuation of L1 mid-vertebra level (L1 Hounsfield units [HU]) were measured. Fifty-seven patients (mean age, 65.5±10.6; 70.2% males) were analyzed, and the median duration was 31 months. Fortyseven patients (82.5%) lost weight after gastrectomy. Baseline SMA and VFA did not differ between the bone loss and preserved groups; however, baseline SFA was significantly higher in the bone preserved group than in the bone loss group (P=0.020). In a multivariable linear regression model adjusted for confounding factors, one standard deviation higher VFA at baseline was associated with greater annualized L1 HU loss (%) (P=0.034). However, higher preoperative SFA was associated with protection against bone loss after gastrectomy (P=0.025). Higher preoperative SFA exhibited a protective effect against bone loss after gastrectomy in patients with non-metastatic gastric cancer, whereas VFA exhibited a negative effect.

Progress of Ossification after Mandibular Reconstruction by Free Fibula Flap Depending on Different Timing of Radiotherapy: A Retrospective 3D Analysis by CT Scans.

Background: The aim of this study was to evaluate the difference between pre- and post-operative radiotherapy on the progress of ossification after free fibula flap reconstruction of the mandible using three-dimensional (3D) analysis. Methods: A total of 38 free fibula reconstructions of the mandible were evaluated retrospectively for ossification between bone segments by measuring Hounsfield Units (HU) in at least two postoperative computer tomography scans (average of 2.4 scans per patient; around the 5th, 12th, 16th, and 19th month postoperative). Three subgroups were created according to the time of irradiation: preoperative radiotherapy (preORT) (n = 11), postoperative radiotherapy (postORT) (n = 16), and patients without any radiation therapy (n = 11) as the control group (noRT). HU in eight regions of interest (ROI) and overlapping surfaces between segments per contact point, as well as influencing factors, were analyzed. Results: The fastest progress in gain of HU ossification with a difference of 0.30 HU/day was observed in noRT compared to preORT (p = 0.002). postORT was -0.24 HU/day slower than preORT (p = 0.005). Original and grafted bone showed a significantly slower HU uptake than between two graft segments with -84.18 HU/day (p < 0.001). Moreover, a larger initial overlapping surface between the segments in cm2 resulted in a higher rise of HU/day (p < 0.001). Conclusions: 3D analysis of post-reconstructive CT scans shows prolonged ossification of mandible reconstructions by free fibula after head and neck radiation. The effect is distinct in cases with post-operative adjuvant radiotherapy. The effects of radiotherapy on ossification may be minimized by a larger initial contact surface and improved operational techniques. Moreover, HU longitudinal measurements and 3D analysis offer new perspectives for clinical evaluation of successful bony healing.

Fully automated determination of robotic pedicle screw accuracy and precision utilizing computer vision algorithms

Historically, pedicle screw accuracy measurements have relied on CT and expert visual assessment of the position of pedicle screws relative to preoperative plans. Proper pedicle screw placement is necessary to avoid complications, cost and morbidity of revision procedures. The aim of this study was to determine accuracy and precision of pedicle screw insertion via a novel computer vision algorithm using preoperative and postoperative computed tomography (CT) scans. Three cadaveric specimens were utilized. Screw placement planning on preoperative CT was performed according to standard clinical practice. Two experienced surgeons performed bilateral T2–L4 instrumentation using robotic-assisted navigation. Postoperative CT scans of the instrumented levels were obtained. Automated segmentation and computer vision techniques were employed to align each preoperative vertebra with its postoperative counterpart and then compare screw positions along all three axes. Registration accuracy was assessed by preoperatively embedding spherical markers (tantalum beads) to measure discrepancies in landmark alignment. Eighty-eight pedicle screws were placed in 3 cadavers’ spines. Automated registrations between pre- and postoperative CT achieved sub-voxel accuracy. For the screw tip and tail, the mean three-dimensional errors were 1.67 mm and 1.78 mm, respectively. Mean angular deviation of screw axes from plan was 1.58°. For screw mid-pedicular accuracy, mean absolute error in the medial–lateral and superior–inferior directions were 0.75 mm and 0.60 mm, respectively. This study introduces automated algorithms for determining accuracy and precision of planned pedicle screws. Our accuracy outcomes are comparable or superior to recent robotic-assisted in vivo and cadaver studies. This computerized workflow establishes a standardized protocol for assessing pedicle screw placement accuracy and precision and provides detailed 3D translational and angular accuracy and precision for baseline comparison.

Mini-Invasive Endoscope-Assisted Treatment of Metopic Craniosynostosis: 2-Dimensional Operative Video.

The surgical treatment of trigonocephaly has undergone significant evolution, with an increasing use of a minimally invasive technique. The endoscope-assisted metopic suturectomy is currently considered a valid surgical option for the correction of metopic craniosynostosis.1-5 In this video-article, we present our surgical technique performed on a 5-month-old patient with type III (Genitori's classification6) trigonocephaly. The computed tomography (CT) scan showed fusion of the metopic suture with bitemporal narrowing and hypotelorism. The patient underwent endoscope-assisted metopic suturectomy, the width of the suturectomy is 1 cm, and an Esmarch sheet was used to protect the dura mater while drilling. Bridging veins are coagulated under endoscopic vision. The suturectomy is considered complete when the nasal cartilages are exposed, deconnecting thus completely the orbits. The postoperative CT scan showed the extent of the suturectomy. The patient did not present any neurological deficit or complications after surgery and was discharged on postoperative day 2. No helmet was used postoperatively. The patient repeated a head CT at age 11 years after head trauma and was seen at consultation. Interestingly, once the bone gap created after the metopic suturectomy reossifies, the frontal sinus develops normally. The long-term result was quite satisfying. The advantages of the mini-invasive technique consist in a smaller surgical scar, lower blood loss, shorter surgical time, and shorter hospital stay with good long-term results. The parents provided written consent for the publication of the patient's picture, the institutional research board approved the submission of this video article. In the video, the tips, tricks, and pitfalls of the technique are discussed.

Midterm Outcome of Branch Vessel Stenting for Superior Mesenteric Artery Malperfusion Complicating with Acute Aortic Dissection.

To investigate the midterm stent patency and patient prognosis after stenting for superior mesenteric artery malperfusion complicating with acute aortic dissection. Thirteen patients who underwent branch vessel stenting for superior mesenteric artery malperfusion between 2011 and 2021 in six institutions were retrospectively reviewed. By comparing pre- and postoperative computed tomography scans in the same plane, the length of the stent implanted in the superior mesenteric artery and the stent-to-vessel diameter ratio were measured. The technical and clinical success of stenting, midterm patient prognosis, and stent patency were evaluated. Superior mesenteric artery stenting was technically successful in 12 patients (92.3%). The mean length of the stents implanted in the superior mesenteric artery was 61.3 ± 39.4 mm (range, 14-127 mm). The mean proximal and distal stent-to-vessel diameter ratios were 1.02 ± 0.16 and 1.30 ± 0.42, respectively. A weak correlation was found between the length of the stents implanted in the superior mesenteric artery and the distal stent-to-vessel diameter ratio (R2 = 0.34). Two major complications occurred, one of which resulted in death within 30 days, and 12 (92.3%) were clinically successful. Of these 12 patients, no recurrent intestinal ischemia occurred during the follow-up duration (mean, 45.2 months). Partial occlusion of the stent distal edge without intestinal ischemia was observed in one patient (distal stent-to-vessel diameter ratio = 2.33) 42 months after stenting. The overall survival rate and primary stent patency rate were 84.6% and 91.7%, respectively. Midterm stent patency and survival after superior mesenteric artery stenting for malperfusion were acceptable.

Longitudinal Assessment of Clinical Outcomes After Arthroscopic Treatment for Hip Synovial Chondromatosis and the Effect of Residual Loose Bodies: Minimum 4-Year and 8-Year Follow-up

Background: Arthroscopic treatment is recommended for hip synovial chondromatosis. However, evidence regarding long-term clinical outcomes is limited. Purpose: To evaluate long-term patient-reported outcomes (PROs) and survival, and to determine the potential effect of residual loose bodies, as evaluated by immediate postoperative computed tomography (CT), on clinical outcomes. Study Design: Case series; Level of evidence, 4. Methods: A consecutive cohort of patients undergoing arthroscopic treatment and diagnosed with synovial chondromatosis between March 2010 and May 2015 were included in the study. Preoperative radiography, CT, and magnetic resonance imaging were performed. Preoperative, midterm (minimum of 4 years), and long-term (minimum of 8 years) PROs were collected for visual analog scale for pain, modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), and 12-item international Hip Outcome Tool (iHOT-12). The percentages achieving minimal clinically important difference (MCID) were calculated. PROs and survival were compared between patients with and without residual loose bodies evident on immediate postoperative CT scan. Results: A total of 28 patients (20% of patients were lost to follow-up) were included in the study with a mean follow-up period of 104.9 months (range, 96-139 months). PROs including visual analog scale for pain (preoperative, 3.8 ± 1.2; midterm, 0.9 ± 1.7; long-term, 0.8 ± 1.4), mHHS (preoperative, 66.4 ± 14.4; midterm, 92.8 ± 12.3; long-term, 93.5 ± 10.5), NAHS (preoperative, 45.2 ± 16.2; midterm, 81.8 ± 15.3; long-term, 83.1 ± 12.9), and iHOT-12 (preoperative, 48.4 ± 15.6; midterm, 69.3 ± 11.7; long-term, 72.7 ± 11.4) were improved at both midterm and long-term follow-up (all with P < .001). In total, 27 (96.4%), 28 (100%), and 26 (92.9%) patients achieved MCID for mHHS, NAHS and iHOT-12, respectively, at the long-term follow-up. No significant difference was found in any of the PROs and the rate of achieving MCID between midterm and long-term follow-up (all with P > .05). One patient (3.6%) underwent revision surgery. Among the 23 patients who had loose bodies on preoperative CT or radiographs, 14 patients (60.9%) with residual loose bodies evident on immediate postoperative CT demonstrated lower NAHS (P = .045) and iHOT-12 (P = .037) scores but a comparable survival (P > .05) at long-term follow-up compared with those who did not have loose bodies. Conclusion: Arthroscopic treatment for hip synovial chondromatosis achieved satisfactory long-term clinical outcomes with strong survival. Most patients maintained or improved their overall functional status between midterm and long-term follow-up. Furthermore, patients with residual loose bodies had less favorable clinical outcomes, although the survival rate was comparable.