Influence of Gradual Elongation to the Patella Tendon Insertion in Rabbits

The purpose of this study was to examine the histological changes at the patella tendon (PT) insertion site under gradual elongation in rabbits. Gradual elongation of the PT was performed using external fixation for 4 weeks, with a lengthening speed of 0.5 mm/day (elongation group; n = 24). Rabbits in the sham group underwent the same surgical procedure without gradual elongation (sham group; n = 24). Eight animals were sacrificed 1, 2 and 4 weeks after surgery in each group, respectively. Average thicknesses of stained glycosaminoglycan (GAGs) areas by Safranin-O staining in the total cartilage layer and the uncalcified fibrocartilage layer in the elongation group were significantly higher than that in the sham group at 4 weeks (p < 0.05) and that in the intact PT group (n = 6, p < 0.05). In the elongation group, the peak in the average thicknesses of the stained GAGs areas in the total cartilage layer and the uncalcified fibrocartilage layer were observed at 4 weeks. Gradual elongation of PT insertion significantly affected the increase in the average thicknesses of the stained GAGs areas in the cartilage layer especially in the uncalcified fibrocartilage layer at 4 weeks in rabbits. Clinically, insertions of tendon and ligament can extend during gradual elongation using external fixation more than 4 weeks after the operation

Cefazolin-containing poly(ε-caprolactone) sponge pad to reduce pin tract infection rate in rabbits

AbstractIn our previous study, a fibroblast growth factor-2 (FGF-2)–apatite composite layer coated on titanium screws effectively prevented pin tract infection in rabbits because of enhanced wound healing; however, the FGF-2–apatite composite layers did not completely prevent pin tract infection. Thus, we recently developed a poly(ε-caprolactone) (PCL) sponge pad embedded with cefazolin sodium (+CEZ), which has a fast-acting bactericidal effect. The pad is placed on the skin around the screws. The purpose of this study was to determine the anti-infective efficacy of the +CEZ pad on the pin–skin interface of the FGF-2–apatite-coated titanium screws. The +CEZ pads were prepared by mixing PCL and CEZ in 1,4-dioxane, followed by freeze-drying and compaction. They were analyzed regarding their surface structure, in vitro CEZ release profile, and bactericidal activity. The FGF-2–apatite-coated screws were implanted percutaneously in bilateral rabbit proximal tibial metaphyses—with and without the +CEZ pad—for 4 weeks (n = 20). The + CEZ pads consisted of a porous matrix of PCL in which CEZ was embedded. The CEZ-release profile showed an initial burst on Day 1 and a sustained release lasting for 30 days. The +CEZ pad retained its bactericidal activity against Staphylococcus aureus after preincubation on an agar plate for 7 days. Based on visual inspection, the pin tract infection rate was successfully reduced from 72.2% to 15.0% with the +CEZ pad (p < 0.05), which reduced the bacterial count, especially S. aureus (p < 0.05). The histological inflammation rate of the soft tissues was also significantly lower with the +CEZ pad than without it (p < 0.05). The pin tract infection rate was reduced to one-fifth with the +CEZ pad. Using it as described improves infection resistance during percutaneous implantation

Simultaneous Three-Dimensional Analysis of Cervical Spine Kinematics in the Axial and Sagittal Views during a Simulated Frontal Impact: Differences between Tensed and Relaxed States

Study DesignProspective experimental study on humans.PurposeTo determine whether postural differences during a low-speed impact are observed in the sagittal and axial views, particularly in a relaxed state.Overview of Literature: Three-dimensional motion capture systems have been used to analyze posture and head-neck-torso kinematics in humans during a simulated low-speed impact, yet little research has focused on the axial view. Since a seatbelt asymmetrically stabilizes a drivers right shoulder and left lower waist into the seat, it potentially creates movement in the axial view.MethodsThree healthy adult men participated in the experimental series, which used a low-speed sled system. The acceleration pulse created a full sine shape with a maximum acceleration of 8.0 m/s2 at 500 ms, during which the kinematics were evaluated in relaxed and tensed states. The three-dimensional motion capture system used eight markers to record and analyze body movement and head-neck-torso kinematics in the sagittal and axial views during the low-speed impact. Head and trunk rotation angles were also calculated.ResultsLarger movements were observed in the relaxed than in the tensed state in the sagittal view. The cervical and thoracic spine flexed and extended, respectively, in the relaxed state. In the axial view, larger movements were also observed in the relaxed state than in the tensed state, and the left shoulder rotated.ConclusionsDuring simulated frontal impact, the rotation angle between the head and trunk was significantly larger in the relaxed state. Therefore, we recommend also observing movement in the axial view during impact tests

Enhanced wound healing associated with Sharpey’s fiber-like tissue formation around FGF-2-apatite composite layers on percutaneous titanium screws in rabbits

BACKGROUND:Pin-tract infections are the most common complications of external fixation. To solve the problem, we developed a fibroblast growth factor-2 (FGF-2)-apatite composite layer for coating titanium screws. The purpose of this study was to elucidate the mechanism of the improvement in infection resistance associated with FGF-2-apatite composite layers.METHOD:We analyzed FGF-2 release from the FGF-2-apatite composite layer and the mitogenic activity of the FGF-2-apatite composite layer. We evaluated time-dependent development of macroscopic pin-tract infection around uncoated titanium control screws (n = 10). Screws coated with the apatite layer (n = 16) and FGF-2-apatite composite layer (n = 16) were percutaneously implanted for 4 weeks in the medial proximal tibia in rabbits.RESULTS:A FGF-2-apatite composite layer coated on the screws led to the retention of the mitogenic activity of FGF-2. FGF-2 was released from the FGF-2-apatite composite layer in vitro for at least 4 days, which corresponds to a period when 30% of pin-tract infections develop macroscopically in the percutaneous implantation of uncoated titanium control screws. The macroscopic infection rate increased with time, reaching a plateau of 80-90% within 12 days. This value remained unchanged until 4 weeks after implantation. The screws coated with an FGF-2-apatite composite layer showed a significantly higher wound healing rate than those coated with an apatite layer (31.25 vs. 6.25%, p < 0.05). The interfacial soft tissue that bonded to the FGF-2-apatite composite layer is a Sharpey\u27s fiber-like tissue, where collagen fibers are inclined at angles from 30 to 40° to the screw surface. The Sharpey\u27s Wber-like tissue is rich in blood vessels and directly bonds to the FGF-2-apatite composite layer via a thin cell monolayer (0.8-1.7 μm thick).CONCLUSION:It is suggested that the enhanced wound healing associated with the formation of Sharpey\u27s fiber-like tissue triggered by FGF-2 released from the FGF-2-apatite composite layer leads to the reduction in the pin-tract inflammation rate

Cell death and cell proliferation in cartilage layers in human anterior cruciate ligament tibial insertions after rupture

The purpose of this study is to investigate cellular responses and histological changes of cartilaginous layers in human anterior cruciate ligament (ACL) tibial insertions after rupture compared with those in normal insertions. Fully 16 tibial insertions of ruptured ACLs were obtained during primary ACL reconstructions. We also obtained 16 normal ACL tibial insertions from cadavers. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) to detect apoptosis, proliferating cell nuclear antigen (PCNA) staining, and histological examination were performed. The percentage of TUNEL-positive chondrocytes in ruptured ACL insertions (30.2 ± 15.6%) was higher than that in normal insertions (9.6 ± 5.8%). The percentage of PCNA-positive chondrocytes was significantly different between ruptured ACL insertions (19.9 ± 15.0%) and normal insertions (12.3 ± 7.3%). The average thickness of the cartilage layer, the glycosaminoglycan-stained area, and the number of chondrocytes per millimeter in ruptured ACL insertions was smaller than those in normal insertions. The decrease in the number of chondrocytes owing to an imbalance between cell death and cell proliferation in the ACL insertions after rupture, as compared with normal insertions, may lead to histological changes of the cartilage layer in the insertions. An in-depth understanding of injured ACL insertion may help elucidate the etiology of histological changes and the function and significance of the existence of the cartilage layer of insertion. This understanding may help in developing optimal treatment protocols for ACL injuries if apoptosis and cell proliferation are controlled

Tumor Occupation in the Spinal Canal and Clinical Symptoms of Cauda Equina Schwannoma: An Analysis of 22 Cases

Study DesignRetrospective, radiological study.PurposeTo determine the relationship between clinical symptoms and the extent of tumor occupation of the spinal canal by cauda equina schwannoma.Overview of LiteratureLittle is known about the relationship between the size of tumors of the cauda equina and the manifestation of clinical symptoms. We analyzed this relationship by estimating the percentage of tumor occupation (PTO) in the spinal canal in cauda equina schwannomas and by correlating this parameter with the presence and severity of clinical symptoms.MethodsTwenty-two patients (9 men and 13 women; age, 19–79 years; mean age, 55.3 years) who were radiologically diagnosed with schwannomas of the cauda equina between April 2004 and July 2014 were retrospectively analyzed. PTO was measured in axial and sagittal magnetic resonance imaging slices in which the cross-sectional area of the tumor was the largest. Data regarding clinical symptoms and results of physical examinations were collected from patient medical records. PTO differences between symptom-positive and -negative groups were analyzed for each variable.ResultsIn the 4 cases in which tumor presence was not related to clinical symptoms, PTO was 5%–10% (mean, 9%) in axial slices and 23%–31% (mean, 30%) in sagittal slices. In the 18 cases in which symptoms were associated with the tumor, PTO was 11%–86% (mean, 50%) in axial slices and 43%–88% (mean, 71%) in sagittal slices. PTO in axial slices was significantly higher in the presence of Déjèrine symptoms and/or muscle weakness, a positive straight leg raise test, and a positive Kemp sign.ConclusionsPTO >20% in axial slices and >40% in sagittal slices can be an indication of symptomatic cauda equina schwannoma

Feasibility of Rehabilitation Training With a Newly Developed Wearable Robot for Patients With Limited Mobility

ObjectiveTo investigate the feasibility of rehabilitation training with a new wearable robot.DesignBefore-after clinical intervention.SettingUniversity hospital and private rehabilitation facilities.ParticipantsA convenience sample of patients (N=38) with limited mobility. The underlying diseases were stroke (n=12), spinal cord injuries (n=8), musculoskeletal diseases (n=4), and other diseases (n=14).InterventionsThe patients received 90-minute training with a wearable robot twice per week for 8 weeks (16 sessions).Main Outcome MeasuresFunctional ambulation was assessed with the 10-m walk test (10MWT) and the Timed Up & Go (TUG) test, and balance ability was assessed with the Berg Balance Scale (BBS). Both assessments were performed at baseline and after rehabilitation.ResultsThirty-two patients completed 16 sessions of training with the wearable robot. The results of the 10MWT included significant improvements in gait speed, number of steps, and cadence. Although improvements were observed, as measured with the TUG test and BBS, the results were not statistically significant. No serious adverse events were observed during the training.ConclusionsEight weeks of rehabilitative training with the wearable robot (16 sessions of 90min) could be performed safely and effectively, even many years after the subjects received their diagnosis

Calcium phosphate-hybridized tendon graft to enhance tendon-bone healing two years after ACL reconstruction in goats

Abstract Background We developed a novel technique to improve tendon-bone attachment by hybridizing calcium phosphate (CaP) with a tendon graft using an alternate soaking process. However, the long-term result with regard to the interface between the tendon graft and the bone is unclear. Methods We analyzed bone tunnel enlargement by computed tomography and histological observation of the interface and the tendon graft with and without the CaP hybridization 2 years after anterior cruciate ligament (ACL) reconstruction in goats using EndoButton and the postscrew technique (CaP, n = 4; control, n = 4). Results The tibial bone tunnel enlargement rates in the CaP group were lower than those in the control group (p p p Conclusions The CaP-hybridized tendon graft enhanced the tendon-bone healing 2 years after ACL reconstruction in goats. The use of CaP-hybridized tendon grafts can reduce the bone tunnel enlargement and gap area associated with the direct insertion-like formation in the interface near the joint.</p

Complications Associated With Spine Surgery in Patients Aged 80 Years or Older: Japan Association of Spine Surgeons with Ambition (JASA) Multicenter Study

Study Design:Retrospective study of registry data.Objectives:Aging of society and recent advances in surgical techniques and general anesthesia have increased the demand for spinal surgery in elderly patients. Many complications have been described in elderly patients, but a multicenter study of perioperative complications in spinal surgery in patients aged 80 years or older has not been reported. Therefore, the goal of the study was to analyze complications associated with spine surgery in patients aged 80 years or older with cervical, thoracic, or lumbar lesions.Methods:A multicenter study was performed in patients aged 80 years or older who underwent 262 spinal surgeries at 35 facilities. The frequency and severity of complications were examined for perioperative complications, including intraoperative and postoperative complications, and for major postoperative complications that were potentially life threatening, required reoperation in the perioperative period, or left a permanent injury.Results:Perioperative complications occurred in 75 of the 262 surgeries (29%) and 33 were major complications (13%). In multivariate logistic regression, age over 85 years (hazard ratio [HR] = 1.007, P = 0.025) and estimated blood loss ≥500 g (HR = 3.076, P = .004) were significantly associated with perioperative complications, and an operative time ≥180 min (HR = 2.78, P = .007) was significantly associated with major complications.Conclusions:Elderly patients aged 80 years or older with comorbidities are at higher risk for complications. Increased surgical invasion, and particularly a long operative time, can cause serious complications that may be life threatening. Therefore, careful decisions are required with regard to the surgical indication and procedure in elderly patients

Risk Factors for Delirium After Spine Surgery in Extremely Elderly Patients Aged 80 Years or Older and Review of the Literature: Japan Association of Spine Surgeons with Ambition Multicenter Study

Study Design:Retrospective database analysis.Objective:Spine surgeries in elderly patients have increased in recent years due to aging of society and recent advances in surgical techniques, and postoperative complications have become more of a concern. Postoperative delirium is a common complication in elderly patients that impairs recovery and increases morbidity and mortality. The objective of the study was to analyze postoperative delirium associated with spine surgery in patients aged 80 years or older with cervical, thoracic, and lumbar lesions.Methods:A retrospective multicenter study was performed in 262 patients 80 years of age or older who underwent spine surgeries at 35 facilities. Postoperative complications, incidence of postoperative delirium, and hazard ratios of patient-specific and surgical risk factors were examined.Results:Postoperative complications occurred in 59 of the 262 spine surgeries (23%). Postoperative delirium was the most frequent complication, occurring in 15 of 262 patients (5.7%), and was significantly associated with hypertension, cerebrovascular disease, cervical lesion surgery, and greater estimated blood loss (P < .05). In multivariate logistic regression using perioperative factors, cervical lesion surgery (odds ratio = 4.27, P < .05) and estimated blood loss ≥300 mL (odds ratio = 4.52, P < .05) were significantly associated with postoperative delirium.Conclusions:Cervical lesion surgery and greater blood loss were perioperative risk factors for delirium in extremely elderly patients after spine surgery. Hypertension and cerebrovascular disease were significant risk factors for postoperative delirium, and careful management is required for patients with such risk factors