Postoperative Computed Tomography Images Research Articles

Orbital Soft Tissue Displacement After Blow-Out Fracture Repair Using Poly (L-Lactide-Co-Glycolide) Polymer Plates Based on Image Fusion Technique.

To analyze the displacement of orbital soft tissue after blow-out fracture (BOF) repair with poly (L-lactide-co-glycolide) plates. In this retrospective study, all patients who had undergone repair operations for orbital BOF from 2017 to 2021 were evaluated. Poly (L-lactide-co-glycolide) plates were used as repair materials. Preoperative and postoperative computed tomography images were integrated into the same coordinate system applying image fusion technique and were compared to determine the maximum displacement of orbital tissue after surgical repair. A total of 15 patients were included. Five were male, and 10 were female. Mean age was 33±16 years. Median waiting period was 18 (12-23) days. Six cases were medial wall fractures, 5 were floor fractures, and 4 were combined fractures. Maxillo-ethmoidal strut was involved in 4. Mean defect area was 176.52±108.48mm 2 . Median interval between postoperative imaging examinations was 292 (223-600) days. Mean orbital tissue displacement was 2.6±1.8mm. Using simple and multivariable linear regression analysis, the fracture defect area ( P =0.001) and maxillo-ethmoidal strut involvement ( P =0.013) were found to be significantly associated with orbital tissue displacement. Median orbital volume change was 0.804 (0.647-1.010) cm 3 . Average proptosis variation was 1.2±0.8mm. Poly (L-lactide-co-glycolide) plates were more suitable for orbital BOF with small defect size. Those with large defect or maxillo-ethmoidal strut involved might have greater tissue displacements due to decline of supporting strength of poly (L-lactide-co-glycolide) plates.

Accuracy of a patient-specific 3D-printed drill guide for placement of bicortical screws in atlantoaxial ventral stabilization in dogs.

Atlantoaxial instability (AAI) in dogs refers to abnormal motion at the C1–C2 articulation due to congenital or developmental anomalies. Surgical treatment options for AAI include dorsal and ventral stabilization techniques. Ventral stabilization techniques commonly utilize transarticular and vertebral body screws or pins. However, accurate screw insertion into the vertebrae of C1 and C2 is difficult because of the narrow safety corridors. This study included 10 mixed dogs, 1 Pomeranian, and 1 Shih-Tzu cadaver. All dogs weighed <10 kg. Each specimen was scanned using computed tomography (CT) from the head to the 7th cervical vertebrae. This study used 12 bone models and 6 patient-specific drill guides. Bone models were made using CT images and drill guides were created through a CAD (computer-aided design) program. A total of six cortical screws were used for each specimen. Two screws were placed at each of the C1, C2 cranial, and C2 caudal positions. Postoperative CT images of the cervical region were obtained. The degree of cortex breaching and angle and bicortical status of each screw was evaluated. The number of screws that did not penetrate the vertebral canal was higher in the guided group (33/36, 92%) than in the control group (20/36, 56%) (P = 0.003). The screw angles were more similar to the reference angle compared to the control group. The number of bicortically applied screws in the control group was 28/36 (78%) compared to 34/36 (94%) in the guided group. Differences between the preoperative plan and the length of the applied screw at the C1 and C2 caudal positions were determined by comparing the screw lengths in the guide group. The study results demonstrated that the use of a patient-specific 3D-printed drill guide for AAI ventral stabilization can improve the accuracy of the surgery. The use of rehearsal using bone models and a drilling guide may improve screw insertion accuracy.

Pilot study of a new type of machine vision-assisted stereotactic neurosurgery for EVD placement.

The usage of machine vision technologies for image-based analysis and inspection is increasing. With the advent of the ability to process high-dimension data instantly, the possibilities of machine vision multiply exponentially. Robots now use this technology to assist in surgery. The aim of this study is to explore the efficacy of Surgical Navigation Robot NaoTrac (Brain Navi Biotechnology Co., Ltd.), which utilizes machine vision-inspired technology for patient registration and stereotactic external ventricular drainage (EVD) by the robotic arm. Preoperative and postoperative computed tomography (CT) scans were acquired for each case. The surgeons planned the targets and trajectories with the preoperative CT images. The postoperative CT images were utilized in the accuracy measurements. All 14 cases had cerebrospinal fluid drained through the catheter. The NaoTrac placed the catheter into the frontal horn in one attempt in 13 cases and was able to drain CSF in 12 cases. Not a single case had any bleeding or intraoperative complications. The average time spent on the patient registration was 142.8s. The mean target deviation was 1.68mm, and the mean angular deviation was 1.99°, all within the accepted tolerance for minimal tissue damage. The results of this report demonstrate that machine vision-inspired patient registration is feasible and fast. NaoTrac has demonstrated its accuracy and safety in performing frameless catheter placement in 13 clinical cases. Other stereotactic neurosurgical operations such as stereotactic biopsy, depth electrode placement, deep brain stimulation electrode positioning, and neuroendoscopy may also be benefited from the assistance of NaoTrac.

Patient-specific instrumentation improves the reproducibility of preoperative planning for the positioning of baseplate components with reverse total shoulder arthroplasty: a comparative clinical study in 39 patients.

The application of patient-specific instrumentation (PSI) for reverse total shoulder replacement has been rapidly increasing, which could reduce errors in implant positioning. Although PSI theoretically holds promise, evidence of the accuracy and reliability of PSI in shoulder replacement surgery is limited. Thirty-nine shoulders that underwent reverse total shoulder arthroplasty were included in this study and categorized into two groups: the conventional (n=20) and PSI (n=19) groups. Screw (length and angle) and baseplate (version, inclination, translation, and rotation) positioning were calculated based on postoperative computed tomography images using a three-dimensional measurement tool. The difference between the values of the preoperative target and postoperative measurement was calculated to evaluate the reproducibility of preoperative planning. Screw involvement in the suprascapular and spinoglenoid notches was assessed. Thus, the correlation between the position of the baseplate and the screws was assessed. The mean differences between the planned length and angle (anteroposterior and superoinferior angles) and postoperative measurement in the PSI group were significantly smaller than those in the conventional group. Similarly, the mean difference in baseplate rotation between the planned and postoperative measurements in the PSI group was significantly lower than that in the conventional group (4.5° vs 10.6°; P<.001). The spinoglenoid notch was involved in 10 cases in the conventional group and 2 cases in the PSI group, and this difference was significant (P=.014). Overall, the mean difference between the preoperative and postoperative version, inferior inclination, and rotation values for the baseplate position was significantly correlated with the values for screw position (length and angle). PSI improves the reproducibility of preoperative planning for baseplate and screw positioning and reduces the risk of neurovascular injury in reverse total shoulder arthroplasty.

Three-dimensional analysis of baseplate screw penetration in reverse total shoulder arthroplasty: risk of iatrogenic suprascapular neuropathy by screw violation.

Baseplate screws have been suggested to be a possible cause of suprascapular neuropathy after reverse total shoulder arthroplasty (RTSA). Three-dimensional analyses of screw penetration and confirmation of its clinical impacts are relevant. The study aims to investigate the association between screw penetration and the clinical outcomes. Eighty-two patients who underwent RTSA for a massive rotator cuff tear, cuff tear arthropathy, or osteoarthritis with rotator cuff tear were retrospectively enrolled. They were followed up for a minimum of 12 months, and all underwent computed tomography at 1 year postoperatively. The lengths of the superior and posterior baseplate screws were documented. Postoperative computed tomography images were subjected to 3-dimensional analysis to determine whether superior or posterior screws penetrated the glenoid vault and the location to which they penetrated, and screw-to-nerve distances were measured to estimate risks of screw nerve violation and iatrogenic suprascapular neuropathy. Patients with any screw <5 mm from the suprascapular nerve were deemed to have a high risk. Clinical outcomes (functional scores, ranges of motion, and isometric strengths) of patients in the high- and lower-risk groups were compared. The mean lengths of the superior and posterior screws were 28 ± 4 mm and 18 ± 3 mm, respectively. Penetration was detected for 13% of superior screws and 64% of posterior screws. Sixty-three percent of penetrating superior screws and 5% of penetrating posterior screws were <5 mm from the suprascapular nerve, and therefore, 12% of patients who received RTSA were assessed to have a high risk of iatrogenic suprascapular neuropathy. However, no significant difference was detected in clinical outcomes between the high- and lower-risk patients after a mean follow-up period of 20 months. Twelve percent of patients who received RTSA were assessed to be at high risk of iatrogenic suprascapular neuropathy by baseplate screw penetration. However, the clinical outcomes of RTSA at a minimum follow-up of 1 year were similar in the high- and lower-risk groups.

Risk of interference between the tibial tunnel and locking screws in medial meniscus posterior root repair and open wedge high tibial osteotomy

PurposeTo evaluate whether the frequency of interference between locking screws for the plate fixation and tibial tunnels differs depending on the tibial tunnel positions in a surgical simulation of the transtibial pull-out repair of medial meniscus posterior root tears (MMPRTs) in patients undergoing biplanar open wedge high tibial osteotomy (OWHTO).MethodsSixty-five patients (75 knees) who underwent OWHTO with TomoFix small plate (Depuy Synthes, PA, USA) for medial knee osteoarthritis with varus malalignment were enrolled in this study. Surgical simulation of transtibial pull-out repair of MMPRTs was performed using postoperative computed tomography images. The tibial tunnel was created in the anatomical attachment area of the medial meniscus posterior root. Another aperture of the tibial tunnel was created on the anteromedial (AM) tibial cortex, the posteromedial (PM) tibial cortex, and the anterolateral (AL) tibial cortex in the proximal tibial fragment. The frequency of interference between the tibial tunnel and A–D locking screws was compared in the 3 tibial tunnel positions. In each tibial tunnel position, the locking plate position with and without interference between the tibial tunnel and at least one locking screw was compared.ResultsFor screw A, the frequency of interference with the tibial tunnel in the AL position was higher than that in the AM (P = 0.048) and PM positions (P < 0.001). For screws B and C, the frequency of interference with the tibial tunnel in the AM position was higher than that in the PM (P < 0.001, P = 0.007) and AL positions (P < 0.001, P = 0.001), respectively. For screw D, there was no difference in the frequency of interference with the tibial tunnel among the three positions. The frequency of interference between the tibial tunnel and at least one screw in the AM position was 100%, which was higher than that in the PM (P < 0.001) and AL positions (P < 0.001). In the PM position, the locking plate was placed more posteriorly in the group where the locking screw interfered with the tibial tunnel. In the AL position, the locking plate was placed more parallel to the medial/lateral axis of the tibial plateau in the interference group.ConclusionMaking the tibial tunnel in the AM position should be avoided because interference with locking screws was inevitable. When the tibial tunnel is created in the PM position, interference between the tibial tunnel and screw C should be paid attention. Anterior placement of the locking plate could be useful to prevent interference between locking screws and the tibial tunnel in the PM position. In addition, when the tibial tunnel is created in the AL position, interference between the tibial tunnel and especially screw A among screws A–C should be paid attention. Placing the locking plate in an anteromedial direction could be useful to prevent interference between locking screws and the tibial tunnel in the AL position.Level of evidenceIV

Preliminary Study on Immediate Postoperative CT Images and Values of the Modular Polyetheretherketone Based Total Knee Arthroplasty: An Observational First-in-Human Trial.

BackgroundTotal knee arthroplasty (TKA) is now frequently performed and is highly successful. However, patient satisfaction after TKA is often difficult to achieve. Because of the presence of metallic prosthetic knee joints, there is a lack of imaging tools that can accurately assess the patient's postoperative prosthetic position, soft tissue impingement, and periprosthetic bone density after TKA. We conducted a clinical trial of the world's first totally modular polyetheretherketone (PEEK) TKA and determined the bone density values in the stress concentration area around the prosthesis based on postoperative computed tomography data to reconstruct a three-dimensional model of the PEEK prosthetic knee joint after implantation. Based on the model, the overhang of the prosthesis was measured at various locations on the prosthesis.MethodsAll patients who underwent PEEK-based TKA were postoperatively assessed with radiography and computed tomography (CT). Hounsfield units (HUs) for the different components of the quantitative CT assessment were measured separately.ResultsTen patients (nine female and one male) aged 59–74 (mean 66.9, median 67) years were included. The HU values were as follows: PEEK prosthesis mean 182.95, standard deviation (SD) 4.90, coefficient of variation (CV) 2.68; polyethylene mean −89.41, SD 4.14, CV −4.63; lateral femoral osteochondral mean 192.19, SD 55.05, CV 28.64; lateral tibial osteochondral mean 122.94, SD 62.14, CV 42.86; medial femoral osteophyte mean 180.76, SD 43.48, CV 24.05; and medial tibial osteophyte mean 282.59, SD 69.28, CV 24.52. Analysis of the data at 1, 3, and 6 months showed that the mean PE (p = 0.598) and PEEK (p = 0.916) measurements did not change with the time of measurement. There was a decrease in bone mineral density in the lateral tibia at 3 months (p = 0.044). Otherwise, there was no significant change in bone density in other regions (p = 0.124–0.803). There was no overhang in all femoral prostheses, whereas there were two cases of overhang in tibial prostheses. Overhang measurements do not differ significantly across time points. The overhang measurements were not significantly different at all time points (p = 0.186–0.967).ConclusionPEEK knee joint prosthesis has excellent CT compatibility. The change in periprosthetic bone volume during the follow-up period can be determined using the HU value after CT scan, while the prosthesis position can be assessed. This assessment may potentially guide future improvements in knee prosthesis alignment techniques and artificial knee prosthesis designs.

Caudal Septal Deviation: A Computed Tomography-Based Evaluation Method.

Caudal septal deviation (CSD) correction during septorhinoplasty is challenging, and various surgical modifications and evaluations remain controversial. This study aimed to introduce an objective evaluation method based on computed tomography (CT) images to measure the effectiveness of septorhinoplasty for CSD treatment. We retrospectively analyzed preoperative and postoperative CT images of patients who had undergone functional open septorhinoplasty by the plastic surgery and otorhinolaryngology teams between January and September 2019. Using OsiriX Lite (Pixmeo, Switzerland), CSD was calculated as the distance between the septum midline and palatal plane. Deformation was categorized as C-shaped unilateral or S-shaped bilateral deviations. The change in the distance between preoperative and postoperative images was considered because of surgical intervention. Twenty patients (mean age, 35 years; 13 males [65%], 7 females [35%]) were included. The median deviation was 3.01 mm (range, 0.45-7.34 mm) preoperatively and 1.6 mm (range, 0.5-2.86 mm) postoperatively, indicating a reduction of 1.26 mm (median, P < 0.05) due to surgical intervention. C- and S-shaped deviations were seen preoperatively in 9 (45%) and 11 (55%) patients and postoperatively in 6 (30%) and 14 (70%) patients, respectively. The mean ± SD time of analysis was 7 ± 2.1 minutes. Caudal septal deviation showed significant changes from preoperative to postoperative CT images, based on the distance between the actual septum midline and the constructed straight septum. This allowed effective evaluation of surgical efficacy for septum straightening. Although additional studies are needed, this method allows clearer stratification of surgical outcomes.

Portosystemic Shunt in Pediatric Living Donor Liver Transplant

To evaluate the significance of portosystemic shunts and associated long-term outcomes in living donor liver transplant (LDLT) among pediatric patients. Retrospective review of 121 pediatric patients who underwent LDLT between May 1994 and December 2015 at Taiwan Kaohsiung Chang Gung Memorial Hospital. Pre- and postoperative computed tomography images of the liver were reviewed, and portal vein complications were assessed. Ninety-seven pediatric patients were included in the study, and 70 had portosystemic shunts before transplant. Thirty-three patients have portal systemic shunt (PSS) 6 months after transplant (mean [SD] shunt size, 4.59 [1.98] mm). Thirty-seven patients' portosystemic shunts closed spontaneously (mean [SD] shunt size, 3.14 [1.06] mm). Smaller PSSs tend to close spontaneously with a cutoff point of 3.35 mm by receiver operating characteristic curve (P=.01). Patients with PSS have more portal vein complications than those without PSS (44.3% vs 11.1%, P=.02). Among PSS recipients, patients with portal vein complications tend to have larger PSS size (mean [SD], 4.14 [1.96] mm vs 3.59 [1.48] mm), although the difference is not statistically significant (P=.19). In pediatric patients, preoperative portosystemic shunts are significantly correlated with portal venous complications, some of which require minimal interventions after LDLT with good outcomes. Shunts larger than 3.35 mm tend to persist after transplant with increased portal venous complications.

Microendoscopic Dorsal Laminectomy for Multi-Level Cervical Intervertebral Disc Protrusions in Dogs.

The objective of this study was to evaluate the feasibility and clinical outcomes of microendoscopic dorsal laminectomy for multi-level cervical intervertebral disc protrusions in dogs. Eight client-owned dogs diagnosed with multi-level cervical intervertebral disc protrusions using computed tomography (CT) and magnetic resonance imaging (MRI) were included in this retrospective case series. Microendoscopic dorsal laminectomies (MEL) were performed with an integrated endoscopic system to the cranial and caudal vertebrae of the affected intervertebral joints. Pre- and post-operative neurological status, operation time, intra-operative complications, and postoperative complications were reviewed. Post-operative CT images were obtained to measure the dimensions of laminectomy and compared to those of planned laminectomy. Full endoscopic procedures were feasible in 7 dogs (87.5%) and the laminectomy dimensions were in agreement with pre-operative planning. In all dogs, major intra- and postoperative complications did not occur. Conversion to open surgery was required in one case. Short-term postoperative clinical deterioration was found in two dogs. Long-term clinical outcomes were good and comparable to those reported in previous studies of open dorsal laminectomies. MEL is a promising minimally invasive approach to multi-level cervical dorsal laminectomy for intervertebral disc protrusions. This technique may improve postoperative discomfort compared to the open approach. Further studies are needed to directly compare outcomes between these two approaches.

Volar Lunate Facet Rim Fractures: K-I Classification and Technique.

Background and Purpose It is difficult to capture and safely support a small volar lunate facet (VLF) fragment and obtain sufficient initial fixation. The challenge in treating VLF rim fractures has resulted in various management options. The purpose of this study was to evaluate the clinical and radiological outcomes of a consecutive series of VLF rim fractures of the distal radius treated surgically and to report the Kondo-Imatani (K-I) classification of these fractures, using computed tomography (CT) images and surgical technique, which is termed the Plate buttress and Double tiered subchondral support (PD) technique. Patients and Methods A retrospective review was conducted on 35 patients with VLF rim fractures that included postoperative clinical evaluations, CT images, and radiographs. Description of Technique The PD technique to stabilize the VLF fragment with an anatomical and low-profile volar locking plate (VLP). Results All fractures healed at the final follow-up; Mayo wrist performance score average was 81.7 points (45-100), and the quick disabilities of the arm, shoulder, and hand (quick-DASH) score average was 9.5 points (0-31.8), showing relatively good clinical results. Conclusion VLF rim fragments are not amenable to standard VLP fixation. Unstable fixation may result in postoperative correction loss, aseptic necrosis, malunion, radiocarpal subluxation, and wrist dysfunction. This report described the K-I classification for VLF rim fractures of the distal radius and surgical technique, termed the PD technique, to stabilize the VLF rim fragment with an anatomical and low-profile VLP. Level of Evidence This is a Level IV, case series study.

Effect of drug-eluting bead transarterial chemoembolization loaded with cisplatin on normal dogs.

Transcatheter arterial embolization (TAE) and transcatheter arterial chemoembolization (TACE) are standard treatments for advanced hepatocellular carcinoma (HCC) and particularly for unresectable tumors or liver metastases in humans. However, reports on TACE used in veterinary medicine are few. This study aimed to evaluate the feasibility and safety of drug-eluting bead transarterial chemoembolization (DEB-TACE). We performed DEB-TACE in four clinically normal dogs and pharmacokinetically compared the results against hepatic arterial infusion (HAI) of cisplatin in two dogs. Drug-eluting beads (DEB) loaded with cisplatin were injected through a microcatheter for selective embolization of the left hepatic artery. After embolization, computed tomography (CT) images and histological examination findings were obtained during a 4-week observation period. Serum platinum concentrations were measured to evaluate cisplatin after each procedure. Biochemical analysis was performed during a 12-week observation period. Embolization was successful in all dogs, and there were no clinically apparent abnormalities. Embolization was confirmed up to 4 weeks after DEB-TACE in two of the four dogs and up to 1 week in the other two dogs using postoperative CT images. Cisplatin was not detected in peripheral veins in all dogs after DEB-TACE, but it was detected in trace amounts after HAI. DEB-TACE using cisplatin was safe and well tolerated by normal dogs. DEB-TACE may be useful in terms of determining systemic toxicity and drug concentration within tumors.

Effect of maxillary surgical movement on nasal cavity and maxillary sinus dimensions and function after Le Fort I osteotomy

This study was designed to evaluate the effects of different maxillary movements performed in Le Fort I surgery on the anatomy of the nasal cavity and maxillary sinus, occurrence of rhinosinusitis, and nasal airflow. Patients were divided into three groups: group I underwent pure advancement, group II underwent advancement with yaw rotation, and group III underwent advancement with impaction movements. All evaluations were performed using pre- and postoperative computed tomography images and surveys. Twenty-eight patients were enrolled. The mean pre- and postoperative nasal air volumes in group I were 22.74 ± 6.32 cm3 and 25.17 ± 6.19 cm3, respectively, showing a significant increase (P = 0.041). The mean pre- and postoperative maxillary sinus air volumes were 33.94 ± 13.72 cm3 and 26.28 ± 14.12 cm3 in group II and 35.29 ± 9.58 cm3 and 28.65 ± 8.42 cm3 in group III, respectively, showing significant reductions (P = 0.028 and P = 0.007, respectively). For all movements, the occurrence of septum deviation and nasal airflow impairment was not statistically significant. Pure maxillary advancement movement enhanced nasal cavity air volume. The yaw rotation movement significantly increased quantitative clinical rhinosinusitis symptoms. The risk of airflow impairment following Le Fort I surgery is low.

Does intraoperative periprosthetic occult fracture of the acetabulum affect clinical outcomes after primary total hip arthroplasty?

The frequency of intraoperative periprosthetic occult fracture of the acetabulum (IPOA) in primary total hip arthroplasty (THA) is relatively high. However, the effect of this fracture on clinical outcome and survival of primary THA remains unknown. This study aimed to determine the impact of IPOA on the outcomes of primary THA during a minimum follow-up of 5years. This retrospective case-control study compared the outcomes of primary THA with or without IPOA during a minimum 5-year follow-up. Thirty-eight patients who underwent primary THA with IPOA (O group) were matched to 76 patients without IPOA (C group) between 2004 and 2013 based on age, sex, body mass index, primary diseases, cup diameter, cup design, and additional dome screw. Both groups underwent the same rehabilitation programs after surgery. We evaluated the Japanese Orthopaedic Association clinical outcomes score; postoperative complications, such as nerve injury, dislocation, heterotopic ossification, iliopsoas impingement, or infection; and radiographic outcomes. Additionally, we performed Kaplan-Meier survival analysis with cup aseptic loosening, cup failure revision, and all-cause revision as the endpoints. There were no significant differences in the pre- and postoperative clinical scores, postoperative complication rates, and cup sagittal rotation between the two groups. Radiographic evaluations showed no aggravation of cases to overt fractures. Bone ingrowth was observed in all cases, and none of the acetabular cups had a progressive radiolucent line ≥ 2mm in all the 3 acetabular zones. Ten-year survival rates for cup aseptic loosening and cup failure revision were 100% in both groups; those for all-cause revision were 97.4% (92.0-100%) and 100% in the O and C groups, respectively (p = 0.157). Primary THA with IPOA provides favorable mid- to long-term outcomes. On IPOA diagnosis, although radiographic follow-up is necessary, additional treatments or rehabilitation programs are not required. Furthermore, postoperative computed tomography images for the detection of IPOA may be unnecessary.

Microendoscopic Mini-Hemilaminectomy and Discectomy in Acute Thoracolumbar Disc Extrusion Dogs: A Pilot Study.

The objective of this study was to evaluate the clinical outcomes and complications of a microendoscopic laminectomy and discectomy (MED) for acute thoracolumbar intervertebral disc extrusions in dogs. Eleven client-owned dogs with acute thoracolumbar intervertebral disc extrusions were included in this retrospective case-series. Dogs were diagnosed with acute thoracolumbar intervertebral disc extrusions using computed tomography (CT) and magnetic resonance imaging (MRI). MED was performed with an integrated endoscopic system to the affected intervertebral disc. Surgery time, intra-operative complications, causes of conversion to microscopic surgery if necessary, post-operative complications, and neurological status on presentation at discharge, as well as any further evaluations in hospital, and long-term concerns via owner contact, were recorded. Post-operative CT images were obtained to compare the extent of laminectomy performed to the planned region of laminectomy. The fully endoscopic procedure was completed in eight dogs without major complications. Three cases were converted to an open surgery due to difficulty removing extruded disc material and controlling hemorrhage. The clinical outcome was good in all cases and equivalent to previously reported prognoses after open surgery. MED is an effective and safe alternative to conventional open procedures in dogs with acute thoracolumbar intervertebral disc extrusion.

The Influence of Different Injection Hole Designs of Augmented Pedicle Screws on Bone Cement Leakage and Distribution Patterns in Osteoporotic Patients

To compare cement distribution and leakage for 2 bone cement-augmented screws with different designs of injection holes in patients and the impact of screw locations and bone mineral density (BMD) on the results. This study recruited 40 patients who underwent instrumentation with cement-augmented screws. Screw holes of group A were 4 holes located in the distal one third of screws, while screw holes of group B were 6 holes located in distal, middle, and proximal sites. Postoperative computed tomography images were obtained to evaluate the rate and type of cement leakage and the distribution pattern of cement. The lateral or center position of screw tip, BMD, and T-score were also analyzed for their influence on the results. Of 192 screws, 80 (41.7%) exhibited cement leakage on postoperative computed tomography. The incidence of cement distribution in the posterior half and type B leakage in group B was significantly higher compared with group A. In group A, the probability of cement distribution in the posterior half was significantly increased when the screw was laterally inserted. For both groups, the higher incidence of cement distribution in the posterior half was correlated with lower BMD and T-score. Our results showed that screws with injection holes closer to the screw tip had higher incidences of distribution in the anterior half of the body and lower incidences of type B leakage. Patients with lower BMD and T-scores should be closely monitored, and a more centered position is recommended for screw insertion.

Stress distribution pattern in the distal radioulnar joint before and after ulnar shortening osteotomy in patients with ulnar impaction syndrome

Ulnar shortening osteotomy (USO) for ulnar impaction syndrome potentially leads to degenerative changes of the distal radioulnar joint (DRUJ). This study was performed to evaluate the effect of the sigmoid notch morphology on the stress distribution pattern of the DRUJ using computed tomography (CT) osteoabsorptiometry (CT-OAM). We reviewed the pre- and postoperative transverse CT images of 15 wrists that had undergone USO. The examined wrists were classified into two groups based on the sigmoid notch morphology: the linear-type notch (type L) and the curved-type notch (type C). We calculated and statistically compared the percentage of the high-density area (%HDA) in each divided region of the sigmoid notch. In type L, %HDA was significantly larger in the distal-dorsal region of the sigmoid notch before USO. Postoperatively, in type L, no specific regions showed a significantly different %HDA. In type C, %HDA was significantly larger in the distal-volar region of the sigmoid notch before USO. Postoperatively, %HDA of type C was significantly larger in the proximal-volar region. Our results suggest that in patients with ulnar impaction syndrome, morphological evaluation of the sigmoid notch can serve as a predictor of osteoarthritis in the DRUJ with or without USO.

Comparison of actual amount of movement with surgical treatment objective in the orthognathic maxillary repositioning

ObjectiveTo compare the postoperative position of the maxilla with the surgical treatment objectives (STO) in bimaxillary orthognathic surgery for evaluating the surgical accuracy and investigating the pattern and cause of the discrepancy. MethodsPatients undergoing conventional bimaxillary orthognathic surgery by a single oral and maxillofacial surgeon were enrolled. Utilizing the superimposition of preoperative and postoperative computed tomography images, the actual amounts of positional change of both the maxillary central incisor and first molars were compared with those of STO. All the patients were divided into two groups according to the actual discrepancy between STO and the postoperative position and factors that may affect surgical accuracy were analyzed. ResultsIn 62 cases, the absolute mean value of the positional difference between STO and the actual outcome was 2.20 mm (X-axis, 0.93 mm; Y-axis, 1.31 mm; and Z-axis, 1.09 mm) in the maxillary central incisor. The signed mean value of the central incisor was -0.07 mm, 0.79 mm, and -0.57 mm in the X-, Y-, and Z-axes, respectively, and the value in the Y- and Z-axes showed a statistically significant difference in comparison with STO (P<0.01). Age, sex, skeletal Angle classification, maxillary and mandibular profile, use of 3D virtual surgery, facial asymmetry, and yawing correction did not show a statistically significant correlation with surgical accuracy at the central incisor. ConclusionThere was an acceptable range of discrepancy between postoperative maxillary position and STO after orthognathic surgery; however, there was a tendency for posterior and downward movement in the maxillary anterior teeth.

Extensive Aortic Stent Graft Coverage for Thoracoabdominal Aortic Aneurysm is Associated With Hemorrhagic Complications Induced by Disseminated Intravascular Coagulation

Hybrid endovascular repair for thoracoabdominal aortic aneurysm (TAAA) is a less invasive alternative treatment than conventional open repair. However, disseminated intravascular coagulation (DIC) and hemorrhagic complications can occur postoperatively. We investigated risk factors for hemorrhagic complications after hybrid endovascular TAAA repair. Sixty-one patients who underwent elective hybrid endovascular TAAA repair between 2007 and 2020 were included. Laboratory data before and after placing stent graft were collected, and DIC was diagnosed using a scoring system established by the Japanese Association for Acute Medicine. The length of the stent graft used to cover the aorta was defined as the aortic coverage length, which was measured using the first postoperative computed tomography image. Predictors of unexpected hemorrhagic complications were evaluated. Postoperative thrombocytopenia was observed in 57 (93%) patients, and their platelet count decreased significantly after stent graft placement (14.3 [9.5-18.0] vs. 8.2 [5.4-10.9]×104/µL, P < 0.001). Fifteen (25%) and 45 patients (74%) were diagnosed with DIC before and after stent graft placement, respectively. Hemorrhagic complications were observed in 21 patients (34%). Multivariate logistic regression analysis revealed that aortic coverage length was an independent risk factor for hemorrhagic complications (odds ratio 1.441/50 mm increase; 95% confidence interval, 1.041-1.994, P=0.027). The cutoff value for aortic coverage length obtained from the receiver operating characteristic curve (area under the curve=0.72) was 304.4 mm (sensitivity 0.76, specificity 0.70). Aortic coverage length is a risk factor for hemorrhagic complications. Patients undergoing extensive aortic coverage greater than 304 mm should be closely monitored.

Postoperative computed tomography assessment of anteromedial cortex reduction is a predictor for reoperation after intramedullary nail fixation for pertrochanteric fractures.

Postoperative radiographs are routinely used to assess fracture reduction following intramedullary nail fixation for pertrochanteric fractures, even though computed tomography (CT) is a superior modality. We aimed to determine the association between reduction quality assessed by CT and rates of reoperation and to evaluate the association of reoperation and reduction quality according to the assessment modality (plain radiographs vs. CT). A retrospective analysis of 299 consecutive patients treated with intramedullary nail fixation for pertrochanteric fractures was conducted. Fracture reduction measured by postoperative radiographs and CT was categorized as anatomical type, extramedullary type, or intramedullary type. Postoperative data for analysis included reduction status,tip-apex distance(TAD), screw position in the femoral head, sliding distance, and conditions associated with reoperation. Of the 299 patients included with a mean age of 83.1 ± 8.2years, there were six patients who required reoperation (2.0%). According to the CT assessments, there were 42 intramedullary reductions (14.0%). Patients with a non-intramedullary reduction based on postoperative CT images were significantly more likely to have proper placement of the screw, a reduced TAD, a reduced sliding distance, and a lower reoperation rate than those with an intramedullary reduction (P < 0.05). The reduction quality assessed by postoperative CT was significantly associated with reoperation (95% CI, 1.45-29.31). Intramedullary reduction assessed by CT was associated with reoperation. The reduction quality based on CT findings was more predictive for reoperation than that from plain radiographs.