Seasonal variation of surgically treated distal radius fracture in Japan using inpatient database: cross-sectional study.

INTRODUCTION: The purpose of this study was to clarify the relationship between seasonal variation and distal radius fractures using diagnosis procedure combination data in Japan. MATERIALS AND METHODS: The participants were hospitalized patients who underwent surgical treatment for distal radius fracture as the primary injury at hospitals that introduced the diagnosis procedure combination system between April 2011 and March 2016. We obtained a summary table of the month of admission, region of residence, age at admission, and sex of the patients from the Ministry of Health, Labour and Welfare and evaluated it by month, region, age group, and sex. RESULTS: The total number of patients for the 5 years from 2011 to 2016 was 105,025. There were 29,224 male and 75,801 female participants, with a female-to-male ratio of 2.6. The mean age was 60.2 (standard deviation, 20.8) years. Distal radius fractures occurred more frequently in the winter, especially among female individuals in eastern Japan. Female participants aged ≥ 50 years tended to have a higher incidence of distal radius fracture in winter. The incidence of distal radius fracture among male participants aged 0-19 years was higher from spring to autumn. CONCLUSION: Surgically treated distal radius fractures occur frequently during the winter months among female individuals in eastern Japan or those aged ≥ 50 years and increase from school age to adolescence, especially in male individuals from spring to autumn. We should be aware of the high incidence of distal radius fractures in winter, especially in regions with snowfall and cold temperatures.

Questionnaire survey about the effects of new lifestyles during the pandemic of COVID-19 on upper limb diseases.

BACKGROUND: The novel coronavirus (COVID-19) that emerged in 2019 and spread globally in 2020 has resulted in the imposition of lockdowns or a state of emergency in many cities worldwide. In Japan, a "new lifestyle" is being advocated. We hypothesize that the new lifestyle has changed people's use of their upper limbs during the COVID-19 pandemic. Therefore, through this questionnaire study, we aimed to determine the factors associated with exacerbation of symptoms during the pandemic and to investigate the current status of patients who require hand surgery. METHODS: This study was a prospective multi-center questionnaire survey. This study was conducted in Japan from December 2020 to July 2021 at university and general hospitals in nine prefectures. A questionnaire was administered to patients who visited a hospital with symptoms of nerve entrapment syndrome, osteoarthritis, or tenosynovitis. RESULTS: A total of 502 patients with a mean age of 63.8 years responded. The 240 patients who experienced exacerbation (exacerbated and markedly exacerbated) were compared with other patients (unchanged, improved, and markedly improved). An increase in the time spent on personal computers and smartphones was associated with exacerbation of hand symptoms. Patients who wanted to undergo surgery but were postponed due to COVID-19 accounted for 23.5% of the outpatients. The mean scores for pain, jitteriness, and anxious depression in these patients were significantly higher than those of patients who did not want surgery. CONCLUSIONS: Our results suggest that an increase in the time spent on personal computers and smartphones is associated with exacerbation of hand symptoms during the COVID-19 pandemic. Patients who wanted to undergo surgery but were postponed by COVID-19 experienced greater pain, jitteriness, and anxious depression.

Do Liquid Nitrogen-treated Tumor-bearing Nerve Grafts Have the Capacity to Regenerate, and Do They Pose a Risk of Local Recurrence? A Study in Rats.

BACKGROUND: Under most circumstances, the resection of soft tissue sarcomas of the extremities can be limb-sparing, function-preserving oncologic resections with adequate margins. However, en bloc resection may require resection of the major peripheral nerves, causing poor function in the extremities. Although liquid nitrogen treatment has been used to sterilize malignant bone tumors, its use in the preparation of nerve grafts has, to our knowledge, not been reported. Hence, this study aimed to investigate the tumor recurrence and function after peripheral nerve reconstruction using liquid nitrogen-treated tumor-bearing nerves in a rat model. QUESTIONS/PURPOSES: (1) Do liquid nitrogen-treated frozen autografts have regeneration capabilities? (2) Do liquid nitrogen-treated tumor-bearing nerves cause any local recurrences in vivo in a rat model? METHODS: Experiment 1: Twelve-week-old female Wistar rats, each weighing 250 g to 300 g, were used. A 10-mm-long section of the right sciatic nerve was excised; the prepared nerve grafts were bridge-grafted through end-to-end suturing. The rats were grouped as follows: an autograft group, which underwent placement of a resected sciatic nerve after it was sutured in the reverse orientation, and a frozen autograft group, which underwent bridging of the nerve gap using a frozen autograft. The autograft was frozen in liquid nitrogen, thawed at room temperature, and then thawed in distilled water before application. The third group was a resection group in which the nerve gap was not reconstructed. Twenty-four rats were included in each group, and six rats per group were evaluated at 4, 12, 24, and 48 weeks postoperatively. To assess nerve regeneration after reconstruction using the frozen nerve graft in the nontumor rat model, we evaluated the sciatic functional index, tibialis anterior muscle wet weight ratio, electrophysiologic parameters (amplitude and latency), muscle fiber size (determined with Masson trichrome staining), lower limb muscle volume, and immunohistochemical findings (though neurofilament staining and S100 protein produced solely and uniformly by Schwann cells associated with axons). Lower limb muscle volume was calculated via CT before surgery (0 weeks) and at 4, 8, 12, 16, 20, 24, 32, 40, and 48 weeks after surgery. Experiment 2: Ten-week-old female nude rats (F344/NJcl-rnu/rnu rats), each weighing 100 g to 150 g, were injected with HT1080 (human fibrosarcoma) cells near the bilateral sciatic nerves. Two weeks after injection, the tumor grew to a 10-mm-diameter mass involving the sciatic nerves. Subsequently, the tumor was resected with the sciatic nerves, and tumor-bearing sciatic nerves were obtained. After liquid nitrogen treatment, the frozen tumor-bearing nerve graft was trimmed to a 5-mm-long tissue and implanted into another F344/NJcl-rnu/rnu rat, in which a 5-mm-long section of the sciatic nerve was resected to create a nerve gap. Experiment 2 was performed with 12 rats; six rats were evaluated at 24 and 48 weeks postoperatively. To assess nerve regeneration and tumor recurrence after nerve reconstruction using frozen tumor-bearing nerve grafts obtained from the nude rat with human fibrosarcoma involving the sciatic nerve, the sciatic nerve's function and histologic findings were evaluated in the same way as in Experiment 1. RESULTS: Experiment 1: The lower limb muscle volume decreased once at 4 weeks in the autograft and frozen autograft groups and gradually increased thereafter. The tibialis anterior muscle wet weight ratio, sciatic functional index, muscle fiber size, and electrophysiologic evaluation showed higher nerve regeneration potential in the autograft and frozen autograft groups than in the resection group. The median S100-positive areas (interquartile range [IQR]) in the autograft group were larger than those in the frozen autograft group at 12 weeks (0.83 [IQR 0.78 to 0.88] versus 0.57 [IQR 0.53 to 0.61], difference of medians 0.26; p = 0.04) and at 48 weeks (0.86 [IQR 0.83 to 0.99] versus 0.74 [IQR 0.69 to 0.81], difference of median 0.12; p = 0.03). Experiment 2: Lower limb muscle volume decreased at 4 weeks and gradually increased thereafter. The median muscle fiber size increased from 0.89 (IQR 0.75 to 0.90) at 24 weeks to 1.20 (IQR 1.08 to 1.34) at 48 weeks (difference of median 0.31; p< 0.01). The median amplitude increased from 0.60 (IQR 0.56 to 0.67) at 24 weeks to 0.81 (IQR 0.76 to 0.90) at 48 weeks (difference of median 0.21; p < 0.01). Despite tumor involvement and freezing treatment, tumor-bearing frozen grafts demonstrated nerve regeneration activity, with no local recurrence observed at 48 weeks postoperatively in nude rats. CONCLUSION: Tumor-bearing frozen nerve grafts demonstrated nerve regeneration activity, and there was no tumor recurrence in rats in vivo. CLINICAL RELEVANCE: A frozen nerve autograft has a similar regenerative potential to that of a nerve autograft. Although the findings in a rat model do not guarantee efficacy in humans, if they are substantiated by large-animal models, clinical trials will be needed to evaluate the efficacy of tumor-bearing frozen nerve grafts in humans.

Significant Improvement After Surgery for a Symptomatic Osteoblastoma in a Patient with Camurati-Engelmann Disease: Case Report and Literature Review.

Camurati-Engelmann disease (CED) is a rare, progressive diaphyseal dysplasia characterized as diaphyseal hyperostosis and sclerosis of the long bones. Corticosteroids, bisphosphonates, and losartan have been reported to be effective systemic medications used to reduce CED symptoms. There are no reports of osteoblastoma in patients with CED, and osteoblastoma in the distal radius is rare. We present a patient diagnosed with CED, based on radiological and histological examinations, at 11 years old. At 22 years old, she experienced severe pain in her right forearm and was treated with bisphosphonate, losartan, and prednisolone; however, the pain continued. An expansive and sclerotic lesion at the distal radius was observed on radiography. A follow-up plain radiograph indicated that the lesion was growing. Fluorodeoxyglucose positron emission tomography revealed solitary, intense radiotracer uptake, and a biopsy and surgical resection were performed due to suspected malignancy. Pathologic analysis showed anastomosing bony trabeculae rimmed by osteoblasts observed in a loose fibrovascular stroma. The lesion was diagnosed as an osteoblastoma. Following bone excision and artificial bone grafting, the patient's severe pain almost completely disappeared. At final follow-up, no evidence of osteoblastoma recurrence was noted. To our knowledge, this is the first case report of osteoblastoma arising in a patient with CED. Bone excision and artificial bone grafting may be a treatment option for local symptomatic osteoblastoma in patients with CED.

Diagnostic accuracies of intraoperative frozen section and permanent section examinations for histological grades during open biopsy of bone tumors.

BACKGROUND: A histological diagnosis obtained from an intraoperative frozen section (FS) during biopsy confirms the adequacy of tumor tissue in the specimen. However, some cases show a discrepancy among the intraoperative FS diagnosis, permanent section (PS) diagnosis of the biopsy specimen, and the final diagnosis of the excised tumor specimen. In this study, we retrospectively investigated the diagnostic accuracy of the FS and PS for different types of bone tumors. METHODS: This study included 377 patients with 411 bone tumors who underwent tumor excision after an open biopsy with intraoperative FS diagnosis. FS, PS, and final diagnoses of the patients were classified into benign tumors/tumor-like lesions, intermediate malignancies, and malignant tumors. To assess diagnostic accuracy, the histological grades in FS and PS diagnoses were compared with those in the final diagnoses. RESULTS: The overall diagnostic accuracies of FS and PS were 93% and 97%, respectively. The accuracy of FS and PS for histological grade was 84% and 93% for chondrogenic tumors, 90% and 96% for osteogenic tumors, 97% and 98% for osteoclastic giant cell-rich tumors, 100% and 100% for tumors of undefined neoplastic nature, and 95% and 99% for other bone tumors, respectively. CONCLUSION: These data suggest that surgical planning based on PS diagnosis is recommended for chondrogenic and osteogenic tumors.

Facilitatory effects of artificial nerve filled with adipose-derived stem cell sheets on peripheral nerve regeneration: An experimental study.

BACKGROUND: We evaluated how artificial nerves filled with adipose-derived stem cell (ADSC) sheets could facilitate peripheral nerve regeneration. METHODS: We prepared ADSC sheets following previously described protocols. We transected the sciatic nerve in 12-week-old Wistar rats, fixed the nerve ends to the artificial conduit, and prepared three groups: (1) conduits alone (control group); (2) conduits filled with ADSCs (ADSCs group), and (3) conduits filled with ADSC sheets (ADSC sheet group). We assessed the subjects 4 and 12 weeks post-transplantation (n = 24). We investigated ßIII-tubulin and anti-S100 expression at 4 and 12 weeks post-transplantation, in longitudinal- and cross-sections of the central portion in the regenerated tissues. The vascular endothelial growth factor A (VEGFA) and neuregulin-1 expressions were analyzed using real-time reverse-transcription polymerase chain reaction (real-time RT-PCR). We evaluated the tibialis anterior muscle wet weight (affected/healthy sides, %) and sciatic function index (SFI) 12 weeks post-transplantation. RESULTS: The ADSC sheet group comprised more S100-positive cells than the other groups. The regenerated axon length in the ADSC sheet group was markedly the longest among the studied groups. The immunostaining revealed a positive area in the regenerated tissue center in all groups, tending to be the largest in the ADSC sheet group. The muscle wet weight indicated that the ADSC sheet group exhibited significantly higher weight than the control. The mean SFI showed that the ADSC sheet group exhibited significantly better results than the control. The VEGFA expression was higher both in the ADSC and the ADSC sheet group than in the control. The neuregulin-1 expression was higher both in the ADSC and the ADSC sheet group than in the control. CONCLUSIONS: The ADSC sheets could potentially support transplanting an adequate number of ADSCs at the target site. Compared with the conventional method of attaching ADSCs, the use of ADSC sheets promotes accelerated nerve regeneration.

Enhanced nerve autograft using stromal vascular fraction.

PURPOSE: While many studies have been conducted on peripheral nerve regeneration, few have focused on strengthening the nerve autografts. This study hypothesized that adding autologous stromal vascular fraction (SVF) to a nerve autograft will improve nerve regeneration. The purpose of this study was to compare the results of nerve autograft with and without SVF. METHODS: An adipose tissue sample was excised from the right inguinal region of female Wistar rats, and SVF was separated by centrifugation. The left sciatic nerve was resected at a length of 15 mm and the defect was bridged by a resected nerve autograft. We added SVF with collagen gel around the nerve autograft in the SVF group and added saline in the control group. At 12 weeks after surgery, the wet muscle weight, distal latency, and amplitude of the compound muscle action potential of the tibialis anterior were evaluated by the ratio of left and right sides. Sciatic functional index (SFI) was also evaluated. RESULTS: The wet muscle weight was significantly better in the SVF group than in the control group. The results of distal latency, amplitude, and SFI were not significantly different between the two groups; however, these results tended to be better in the SVF group than in the control group. CONCLUSION: SVF added to artificial nerve grafts has been reported to promote axonal regeneration through secretion of angiogenic, neurotrophic, and anti-apoptotic factors. This study indicates that SVF may also be effective for nerve autografts and improve the clinical result of nerve autograft.

Independent predictors affecting the reduction of pediatric supracondylar humerus fractures: a retrospective cohort study.

BACKGROUND: Although it is important to understand the risk factors affecting the reduction of pediatric supracondylar humerus fractures (PSHFs), no inclusive study has been conducted so far. We performed a retrospective cohort study to identify the risk factors affecting the quality and difficulty of reduction for PSHFs. METHODS: We reviewed 160 cases with a PSHF that had been surgically treated in our hospital between January 2007 and December 2019. We investigated age, sex, injured side, body mass index (BMI), modified Gartland classification, neurological deficit or an absent radial artery pulse at an initial examination, start time of the operation, waiting time from injury to surgery, operative time, reduction technique, and perioperative radiographic parameters. We calculated independent predictors of unsuccessful closed reduction, prolonged operative time, and malreduction using multivariate analyses. RESULTS: In a logistic regression analysis, modified Gartland type III was a significant predictor of unsuccessful closed reduction (OR 14.50 [95% CI 4.03-51.90]; P < 0.01) and BMI was a significant predictor of malrotation (OR 1.59 [95% CI 1.06-2.39]; P = 0.025). In a multiple linear regression analysis, BMI and open reduction were significant predictors of prolonged operative time (BMI, P = 0.011; open reduction, P < 0.01). CONCLUSIONS: If closed reduction fails, we should not hesitate to immediately switch to other methods. Obesity was an independent predictor of both prolonged operative time and malrotation, a finding that has not been previously reported. Rotational alignment should be carefully checked, especially for obese children, and accurately be reduced. Open reduction also extended operative time.

Differentiated adipose-derived stem cells promote peripheral nerve regeneration.

INTRODUCTION: Many reports have indicated that adipose-derived stem cells (ADSCs) are effective for nerve regeneration. We investigated nerve regeneration by combining a polyglycolic acid collagen (PGA-c) tube, which is approved for clinical use, and Schwann cell-like differentiated ADSCs (dADSCs). METHODS: Fifteen-millimeter-long gaps in the sciatic nerve of rats were bridged in each group using tubes (group I), with tubes injected with dADSCs (group II), or by resected nerve (group III). RESULTS: Axonal outgrowth was greater in group II than in group I. Tibialis anterior muscle weight revealed recovery only in group III. Latency in nerve conduction studies was equivalent in group II and III, but action potential was lower in group II. Transplanted dADSCs maintained Schwann cell marker expression. ATF3 expression level in the dorsal root ganglia was equivalent in groups II and III. DISCUSSION: dADSCs maintained their differentiated state in the tubes and are believed to have contributed to nerve regeneration.

Accuracy of histological grades from intraoperative frozen-section diagnoses of soft-tissue tumors.

BACKGROUND: For excised tumor specimens, histological grades can differ between the biopsy diagnosis and the final diagnosis. METHODS: We retrospectively investigated the diagnostic accuracies of histological grades for frozen-section and permanent-section diagnoses from patients with soft-tissue tumors. Frozen-section, permanent-section, and final diagnoses were classified as benign tumors/tumor-like lesions, intermediate malignancies, or malignant tumors. Diagnostic accuracies of the histological grades from the frozen and permanent sections were evaluated by comparing the final diagnoses for the resected specimens. RESULTS: The diagnostic accuracies of the histological grades for the frozen- and permanent-section diagnoses were 95% (387/408 lesions) and 97% (395/408 lesions), respectively. Among the tumor types, the diagnostic accuracies of the histological grades for the frozen-section and permanent-section diagnoses were 84% and 87% for adipocytic tumors, 87% and 91% for fibroblastic/myofibroblastic tumors, 99% and 100% for nerve-sheath tumors, 98% and 98% for fibrohistiocytic tumors, 90% and 98% for tumors of uncertain differentiation, 100% and 100% for vascular tumors, and 97% and 98% for other tumors, respectively. CONCLUSIONS: Histological grades from frozen-section diagnoses yielded low diagnostic accuracies in adipocytic and fibroblastic/myofibroblastic tumors. Treatment should be planned based on permanent-section diagnosis and radiological findings for these tumors.

Risk factors for surgical site infection after malignant bone tumor resection and reconstruction.

BACKGROUND: Use of an implant is one of the risk factors for surgical site infection (SSI) after malignant bone tumor resection. We developed a new technique of coating titanium implant surfaces with iodine to prevent infection. In this retrospective study, we investigated the risk factors for SSI after malignant bone tumor resection and to evaluate the efficacy of iodine-coated implants for preventing SSI. METHODS: Data from 302 patients with malignant bone tumors who underwent malignant bone tumor resection and reconstruction were reviewed. Univariate analyses were performed, followed by multivariate analysis to identify risk factors for SSI based on the treatment and clinical characteristics. RESULTS: The frequency of SSI was 10.9% (33/302 tumors). Pelvic bone tumor (OR: 4.8, 95% CI: 1.8-13.4) and an operative time ≥ 5 h (OR: 3.4, 95% CI: 1.2-9.6) were independent risk factors for SSI. An iodine-coated implant significantly decreased the risk of SSI (OR: 0.3, 95% CI: 0.1-0.9). CONCLUSION: The present data indicate that pelvic bone tumor and long operative time are risk factors for SSI after malignant bone tumor resection and reconstruction, and that iodine coating may be a promising technique for preventing SSI.

Successful joint preservation of distal radius osteosarcoma by en bloc tumor excision and reconstruction using a tumor bearing frozen autograft: a case report.

BACKGROUND: The wrist joint is an extremely rare site for osteosarcoma. Joint structure preservation to maintain good limb function is well described in case of knee osteosarcoma, whereas it is not described in case of wrist joint osteosarcoma. In this report, we present the first case of joint preservation surgery to treat distal radius osteosarcoma using a tumor bearing autograft treated with liquid nitrogen. CASE PRESENTATION: A 46-year-old male presented with swelling and pain in the right wrist and was diagnosed with conventional osteosarcoma of the distal radius. The patient responded well to neoadjuvant chemotherapy and the tumor shrank remarkably. Wide tumor excision to preserve the radiocarpal joint and reconstruction with a tumor bearing frozen autograft were performed. Partial bone union was detected 3 months postoperatively and complete bone union was detected 9 months postoperatively. Following the surgery, there was immediate commencement of the range of motion (ROM) training in both the wrist and fingers. At the final postoperative follow-up of 41 months, the patient had normal ROM in the wrist, fingers, and forearms, with a score of 100% in the Musculoskeletal Tumor Society (MSTS) score and was disease free. CONCLUSION: We present the first case in which en bloc tumor excision with joint preservation of the wrist and reconstruction using a tumor bearing frozen autograft were performed. The surgery yielded excellent hand, wrist, and forearm function at the final follow-up.

Reducing the risk of flexor pollicis longus tendon rupture after volar plate fixation for distal radius fractures: validation of the tendon irritation test.

BACKGROUND: We have proposed that a positive tendon irritation test is suggestive of flexor pollicis longus (FPL) tendon damage that can lead to tendon rupture after volar plate fixation for distal radius fractures. We investigated cases of postsurgical hardware removal and validated the tendon irritation test as a way to elicit a sign of FPL tendon irritation. PATIENTS AND METHODS: We performed hardware removal from 30 wrists in 28 consecutive patients after volar plate fixation. Subjects included 9 men and 19 women with an average age of 58.8 years. The duration of internal fixation averaged 14.5 months. We investigated the efficacy of the tendon irritation test to elicit a sign of tendon irritation before hardware removal, and we intraoperatively evaluated the presence of FPL tendon injuries. RESULTS: Twenty-four of 30 wrists exhibited a sign of tendon irritation. There was no statistical correlation between a sign of tendon irritation and patient age or the duration of internal fixation. We diagnosed 10 wrists with tenosynovitis and 8 frayed tendons. The sensitivity of the tendon irritation test to identify a sign of tendon irritation that was associated with FPL tendon injuries was 80.0%, and its specificity to correctly identify non-injured FPL tendons was 40.0%. The duration of internal fixation associated with tendon fraying was significantly longer than it was in cases of non-injured tendons and tenosynovitis. CONCLUSION: Our results suggest that subsequent examinations should be performed when the tendon irritation test is positive for signs of tendon irritation that may require plate removal.

Medium-term Outcomes of Excision Using Surgical Microscope of Tenosynovial Giant Cell Tumors of the Hand.

BACKGROUND/AIM: The recurrence rate following the excision of tenosynovial giant cell tumors (TSGCT) of the hand is very high. Intraoperative application of a surgical microscope has been reported. However, to date, there are no reports of medium-term outcomes related to this technique. This study aimed to evaluate the medium-term outcomes of tumor excision using surgical microscope for TSGCT of the hand. PATIENTS AND METHODS: A total of 27 patients, who underwent an initial surgery for histologically-confirmed TSGCT of the hand, between 2008 and 2020, were included and evaluated. The mean follow-up time postoperatively was 6.8 years. Tumor recurrence and preoperative tumor characteristics were assessed. RESULTS: All tumors were adherent to tendons, tendon sheaths, neurovascular structures or periarticular ligaments and capsules. Bony lesions were observed in 11 tumors. The surgical microscope was used in 13 tumors. Recurrences were observed in three tumors (overall recurrence rate: 11%). Tumor characteristics were similar in both groups, but the recurrence rate in the group treated using the surgical microscope was 0%, whereas the recurrence rate in the group treated without the surgical microscope was 21%. Re-operations using the surgical microscope for recurrent tumors were performed, without recurrence postoperatively. CONCLUSION: Among patients with TSGCT of the hand treated with tumor excision using the surgical microscope, the postoperative recurrence rate was 0%. Based on the results of this study, the surgical microscope might be used for excision of TSGCTs of the hand.

Development and validation of a nomogram to predict surgical site infection after soft-tissue sarcoma resection.

Aims: Surgical site infection (SSI) after soft-tissue sarcoma (STS) resection is a serious complication. The purpose of this retrospective study was to investigate the risk factors for SSI after STS resection, and to develop a nomogram that allows patient-specific risk assessment. Methods: A total of 547 patients with STS who underwent tumour resection between 2005 and 2021 were divided into a development cohort and a validation cohort. In the development cohort of 402 patients, the least absolute shrinkage and selection operator (LASSO) regression model was used to screen possible risk factors of SSI. To select risk factors and construct the prediction nomogram, multivariate logistic regression was used. The predictive power of the nomogram was evaluated by receiver operating curve (ROC) analysis in the validation cohort of 145 patients. Results: LASSO regression analysis selected possible risk factors for SSI, including age, diabetes, operating time, skin graft or flap, resected tumour size, smoking, and radiation therapy. Multivariate analysis revealed that age, diabetes, smoking during the previous year, operating time, and radiation therapy were independent risk factors for SSI. A nomogram was developed based on the results of multivariate logistic regression analysis. In the development cohort, the incidence of SSI was 4.5% in the low-risk group (risk score < 6.89) and 26.6% in the high-risk group (risk score ≥ 6.89; p < 0.001). In the validation cohort, the incidence of SSI was 2.0% in the low-risk group and 15.9% in the high-risk group (p = 0.004). Conclusion: Our nomogram will enable surgeons to assess the risk of SSI in patients with STS. In patients with high risk of SSI, frequent monitoring and aggressive interventions should be considered to prevent this.

Secretion of matrix metalloproteinase-9 from astrocytes by inhibition of tonic P2Y14-receptor-mediated signal(s).

Glial cells have various important roles in regulation of brain functions. For such events, extracellular nucleotides/P2 receptors have central roles. Although there have been huge amount of literature about activation of P2 receptors and glial functions, little is known about what happens in glia or the brain if glial P2 receptor is inhibited. Here we show that the inhibition of P2 receptors in astrocytes, the most abundant glial cells and cause a constitutive release of nucleotides, resulted in secretion of metalloproteinase-9 (MMP-9), a metal-dependent endopeptidase that degrades extracellular matrix molecules and is important in regulation of brain remodeling. When cultured astrocytes were treated with apyrase (ecto-nucleotidase), reactive blue 2 (P2 receptor antagonist), and pertussis toxin, they secreted MMP-9, suggesting that Gi-coupled P2Y receptor-mediated signals constitutively suppress the production of MMP-9. Among Gi-coupled P2Y receptors, we found that an inhibition of P2Y(14) receptor, a receptor for nucleotide-sugars such as UDP-glucose, is responsible for the production of MMP-9 by pharmacological and molecular biochemical analysis. As for the mechanisms, the inhibition of P2Y(14) receptors resulted in the release of tumor necrosis factor (TNF)-α which then acted on astrocytes to induce MMP-9. Taken together, our results suggest that the constitutive releases of nucleotide-sugars in astrocytes should play an important role in maintaining the normal status of the cell, through Gi-coupled P2Y(14) receptors, and when the signal is removed, the cells start to release TNF-α, which then acts on astrocytes in a feedback fashion to boost MMP-9 synthesis and secretion.

UDP acting at P2Y6 receptors is a mediator of microglial phagocytosis.

Microglia, brain immune cells, engage in the clearance of dead cells or dangerous debris, which is crucial to the maintenance of brain functions. When a neighbouring cell is injured, microglia move rapidly towards it or extend a process to engulf the injured cell. Because cells release or leak ATP when they are stimulated or injured, extracellular nucleotides are thought to be involved in these events. In fact, ATP triggers a dynamic change in the motility of microglia in vitro and in vivo, a previously unrecognized mechanism underlying microglial chemotaxis; in contrast, microglial phagocytosis has received only limited attention. Here we show that microglia express the metabotropic P2Y6 receptor whose activation by endogenous agonist UDP triggers microglial phagocytosis. UDP facilitated the uptake of microspheres in a P2Y6-receptor-dependent manner, which was mimicked by the leakage of endogenous UDP when hippocampal neurons were damaged by kainic acid in vivo and in vitro. In addition, systemic administration of kainic acid in rats resulted in neuronal cell death in the hippocampal CA1 and CA3 regions, where increases in messenger RNA encoding P2Y6 receptors that colocalized with activated microglia were observed. Thus, the P2Y6 receptor is upregulated when neurons are damaged, and could function as a sensor for phagocytosis by sensing diffusible UDP signals, which is a previously unknown pathophysiological function of P2 receptors in microglia.

Uncultured adipose-derived regenerative cells promote peripheral nerve regeneration.

BACKGROUND: We examined whether or not peripheral nerves can be regenerated using uncultured adipose-derived regenerative cells (ADRCs). We also searched for humoral factors that might promote the proliferation or migration of Schwann cells. METHODS: Thirty rats were randomly assigned to three groups. A 10 mm sciatic nerve defect was bridged using a silicon tube filled with physiological saline (control group), type I collagen gel (collagen group), and a mixture of ADRCs and type I collagen gel (ADRC group). The regenerated tissues were studied two weeks after surgery. RESULTS: Continuity of regenerated tissue was observed in all rats in the control group and the ADRC group. In the collagen group, only two rats had a bridge of thin tissue, which was barely visible macroscopically. Protein gene product 9.5 staining confirmed significantly faster regeneration in the ADRC group. The distributions of the PKH-26 positive areas and the S-100 protein positive areas were different, suggesting that the transplanted cells had not differentiated into Schwann cells. In real-time RT-PCR, neuregulin-1 (Neu-1) and vascular endothelial growth factor A (VEGFA) expression were detected in uncultured ADRCs before transplantation. The regenerated tissue in the ADRC group had higher levels of Neu-1 and VEGFA expression than the control group. CONCLUSIONS: ADRCs promote peripheral nerve regeneration. The mechanism does not involve the differentiation of transplanted cells into Schwann cells, but probably involves the secretion of some type of humoral factor such as Neu-1 or VEGFA that promotes the proliferation or migration of Schwann cells.

Ultrasound Investigation of the Radial Nerve's Superficial Branch: Reducing the Risk of K-Wire Insertion Damage in Distal Radius Fractures.

BACKGROUND: Kirschner wire (K-wire) insertion during surgery for distal radius fractures carries a risk of damaging the radial nerve's superficial branch. In this prospective study, we investigated the relationship between the radial nerve's superficial branch and the radius using ultrasound to minimize risk. METHODS: We collected data from 101 healthy volunteers (202 limbs; 51 men; mean age: 40.6 years). We ultrasonographically assessed the courses of the radial nerve's dorsal and superficial palmar branches at 0, 1, 2, and 3 cm proximal to the radial styloid process tip. The positional relationship between the radial nerve's superficial branch and the radius was determined by splitting the radius's ultrasound map into 4 sections (R1-R4) from the palmar side. The section containing the dorsal and palmar branch midpoints was determined for each height. RESULTS: In many limbs, the dorsal branch tended to wrap from the proximal palmar to the distal dorsal side at 1 to 2 cm proximal to the radial styloid process tip. In approximately 90% of limbs, the palmar branch ran along the radius's palmar side rather than the radial surface. CONCLUSIONS: A small incision enabling direct view may be the best approach for avoiding nerve damage when the superficial branch is less than or equal to 2 cm proximal to the tip of the radial styloid process. Inserting the K-wire from the dorsal side of the radius may be safer for more proximal locations. We recommend a preoperative ultrasound examination to determine the course of the superficial branches of the radial nerve in each patient.

Coloration Modeling and Processing of Commodity Plastic Buttons in Supercritical Carbon Dioxide.

We examined the color processing of the commodity plastic buttons made of acrylic, polyester, nylon, and casein with scCO2. The buttons' dyeing color depth (K/S) was measured over a wide range of scCO2 and correlated accurately with the response surface method. Moreover, we measured the solubility of C.I. Disperse Red 22 in scCO2 to formulate a dye-sorption model for the K/S value in the color processing of the plastic buttons. Finally, the dye-sorption model for the K/S value combining the dye solubility in scCO2 with the dye diffusion inside the buttons successfully represented the color processing of the buttons.