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Biomedical subjects

C C Wu

Publications and source records attributed to C C Wu.

At least 19 recordsLinked to original sources

Patellar tension band wiring: a revised technique.

Using a modified AO tension band wiring technique to treat a patellar fracture has become popular and has achieved a high success rate. However, the technique of Kirschner wire insertion has not been considered in detail, which may migrate and consequently introduce fragments loss of reduction. A revised technique involving bending both ends of the Kirschner wires was prospectively studied. Sixty-eight consecutive patients were so treated, and 62 patients were followed-up for at least 2 years (range 2-6 years). All fractures healed with a union rate of 100% (62/62) and a union period of 2.5 +/- 0.5 months. Skin irritation was noted in 2 patients (3%). All patients achieved a satisfactory result. We therefore recommend this revised technique to treat all patellar fractures because of its high union rate and low complication rate.

Adolescent↗

Improving operative safety for cirrhotic liver resection.

BACKGROUND: Liver resection in a patient with cirrhosis carries increased risk. The purposes of this study were to review the results of cirrhotic liver resection in the past decade and to propose safe strategies for cirrhotic liver resection. METHODS: Based on the date of operation, 359 cirrhotic liver resections in 329 patients were divided into two intervals: period 1, from September 1989 to December 1994, and period 2, from January 1995 to December 1999. The patient backgrounds, operative procedures and early postoperative results were compared between the two periods. The factors that influenced surgical morbidity were analysed. RESULTS: In period 2, patient age was higher and the amounts of blood loss and blood transfused were lower. Although postoperative morbidity rates were similar, blood transfusion requirement, postoperative hospital stay and mortality rate were significantly reduced in period 2. No death occurred in 154 consecutive cirrhotic liver resections in the last 38 months of the study. Prothrombin activity and operative time were independent factors that influenced postoperative morbidity. CONCLUSION: With improving perioperative assessment and operative techniques, most complications after cirrhotic liver resection can be treated with a low mortality rate. However, more care should be taken if prothrombin activity is low or there is a long operating time.

Adult↗

Systemic distribution of Staphylococcus aureus following intradermal footpad challenge of broilers.

We conducted an experiment with broilers to determine if prior exposure to Staphylococcus aureus would facilitate the systemic infiltration of this pathogen following intradermal footpad challenge with live S. aureus. Litter-raised broilers were sensitized at 3 and 4 wk of age with s.c. injections in the neck with heat-killed S. aureus diluted in polyethylene glycol (PEG). Equal numbers of control birds were injected at the same times with PEG. At 7 wk of age, chicks previously sensitized to killed S. aureus or injected with PEG were injected intradermally in the right footpad with PBS or live S. aureus. The left footpads of all birds were injected with PBS. The difference in thickness between the right and left footpads was determined at 0, 24, and 48 h postchallenge. Blood, liver, spleen, lung, and synovial fluid were collected six times between 1 and 48 h postchallenge to determine the recovery of S. aureus. Sensitized and non-sensitized birds showed footpad swelling following challenge with live S. aureus in the right footpad (P < 0.001). Injection of PBS did not induce footpad swelling. Birds injected in the footpads with live S. aureus as compared to PBS had significantly higher isolation rates of S. aureus in the spleen, liver, and blood; however, recovery of S. aureus from S. aureus-sensitized and PEG-injected birds was not significantly different. Time postchallenge (1, 3, 7, 11, 24, and 48 h) had no significant effect on the recovery of S. aureus. It was concluded that the intradermal challenge of the footpad with S. aureus resulted in systemic infiltration of S. aureus into the spleen, liver, and blood. Prior exposures to killed S. aureus as compared to PEG controls did not affect the systemic distribution of S.

Analysis of Variance↗

Tension-band technique for ankle fusion.

A prospective study was conducted to develop a better technique for ankle fusion. Eleven consecutive patients were treated using the tension-band technique for ankle fusion and underwent follow-up for a minimum of 2 years (range: 2-5 years). All 11 patients achieved solid fusion for a fusion rate of 100%. Average time to fusion was 3 months (range: 2-6 months). The indication for ankle fusion was intractable aching pain that could not be controlled by conservative methods. Two of 11 patients underwent surgery due to infected arthritis. After ankle fusion, there was no recurrence of infection during a 3-year follow-up period. The technique included osteotomy of the bimalleoli from the inside out, removal of articular cartilage and preserving wedge space for cancellous bone grafting, with or without staple stabilization, and external immobilization supplementation. The functional outcome in all 11 patients improved from unsatisfactory preoperatively to satisfactory at latest follow-up (P<.001). No significant complications were noted. This simple technique proved excellent for ankle fusion with a satisfactory outcome and is recommended for treating severe ankle arthropathies.

Adult↗

Hyperpolarization contributes to vascular hyporeactivity in rats with lipopolysaccharide-induced endotoxic shock.

We have examined the role of membrane hyperpolarization in mediating vascular hyporeactivity induced by bacterial lipopolysaccharide (LPS) in endothelial-denuded strips of rat thoracic aorta ex vivo. The injection of rats with LPS caused a significant fall of blood pressure and a severe vascular hyporeactivity to norepinephrine. The membrane potential recording showed that endotoxemia caused a hyperpolarization when compared to the control. This hyperpolarization was fully restored by methylene blue (MB; 10 microM) and partially reversed by Nomega-nitro-L-arginine methyl ester (L-NAME; 0.3 mM), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 1 microM), tetraethylammonium (TEA; 10 mM), charybdotoxin (CTX; 0.1 microM), or glibenclamide (GB; 10 microM), however, this hyperpolarization was not significantly affected by apamin (0.1 microM), 4-aminopyridine (4-AP; 1 mM), or Ba2+ (50 microM). In addition, the basal tension of the tissues obtained from endotoxemic rats was enhanced by the following order: MB > or = ODQ > TEA > or = L-NAME > or = CTX > GB; whereas apamin, 4-AP or Ba2+ had no significant effects on these tissues. In contrast, none of these inhibitors had significant effects on the membrane potential or the basal tension in control tissues. Our electrophysiological results further confirmed previous studies showing that in addition to nitric oxide, the large conductance Ca2+-activated K+-channels and ATP-sensitive K+-channels are, most likely, responsible for endotoxin-mediated hyporeactivity to vasoconstrictor agents in vascular smooth muscle.

Animals↗

Extracellular Bartonella henselae and artifactual intraerythrocytic pseudoinclusions in experimentally infected cats.

Blood, spleen and liver of specific pathogen-free (SPF) cats and SPF cats experimentally infected with Bartonella henselae were examined. Using immunohistochemical labeling, no intracellular B. henselae were observed in tissues of any cats, but extracellular B. henselae were detected in tissues of infected cats. Pseudoinclusions were detected in erythrocytes of all cats using electron microscopy.

Animals↗

Antimicrobial susceptibility of Mycoplasma hyorhinis.

A broth microdilution technique was used to determine the antimicrobial susceptibility of 15 field isolates of Mycoplasma hyorhinis to 10 antimicrobial agents, representative of different classes, and contrasting newer agents to existing ones. For the macrolides, the MIC(90) for tylosin and tilmicosin was 1 and 4 microg/ml, respectively, but was > or = 16 microg/ml for erythromycin. Tetracycline, lincomycin and enrofloxacin each had an MIC(90) of 2 microg/ml. The mycoplasma had similar levels of susceptibility to the aminoglycoside and aminocyclictol classes exhibiting an MIC(90) of 4 microg/ml for gentamicin and 2 microg/ml for spectinomycin. The isolates exhibited high MICs to trimethoprim/sulfamethoxazole with an MIC(90) > or = 16/304 microg/ml. In summary, M. hyorhinis isolates from the US had low MICs against a variety of antimicrobials tested, with the exception of erythromycin and trimethoprim/sulfamethoxazole.

Animals↗

Comparison of simultaneous dobutamine echocardiography and thallium-201 stress-reinjection single-photon emission computed tomography in predicting improvement of chronic myocardial dysfunction after revascularization.

Previous studies have shown that ultrasonic integrated backscatter is valuable in characterizing stunned myocardium. Recent investigations have demonstrated that resting cardiac cycle-dependent variation of integrated backscatter closely paralleled the contractile reserve in patients with chronic left ventricular ischemic dysfunction. The purpose of this study was to validate whether ultrasonic tissue characterization (UTC) compared with dobutamine stress echocardiography (DSE) and thallium-201 stress-reinjection single-photon emission computed tomography (Tl-SPECT) could predict reversible myocardial dyssynergy in patients with chronic coronary artery disease. Forty-eight patients with stable coronary artery disease underwent UTC, DSE, and Tl-SPECT simultaneously before successful coronary revascularization and were followed up with echocardiograms at rest >3 months later. Among the 58 investigated segments, the weighted amplitude, a composite parameter derived from the integrated backscatter power curve, was larger for those groups with greater functional recovery (p <0.001). For the persistent akinetic segments, the weighted amplitudes were small with large deviations of the nadir ratios that represented the asynchrony between the intramural contractile events and the global systole. Using the cut-off value 2.0 of the weighted amplitude, the sensitivity and specificity for predicting functional improvement after revascularization were both 82.8% (kappa = 0.66) and comparable to the sensitivity and specificity of DSE and Tl-SPECT. UTC, delineating the myocardial physical state and intramural contraction, can be a novel approach in predicting functional improvement of chronic dyssynergy after revascularization.

Adult↗

Effect of ascorbic acid supplementation on the immune response of chickens vaccinated and challenged with infectious bursal disease virus.

One-day-old chickens were divided into two groups and reared under similar conditions. One group was fed a diet supplemented with 1000ppm ascorbic acid and the other group was fed an identical diet, but not supplemented with ascorbic acid. Both groups were vaccinated against infectious bursal disease (IBD) at 7 days of age and challenged orally with 4x10(5) of 50% embryo-lethal-dose IBDV 14 days later. The number of anti-IBDV antibody secreting cells, production of interleukin-2 (IL-2) by splenocytes, number of CD4(+), CD8(+) and IgM(+) cells in spleen and IgM(+) cells in bursa of Fabricius were compared between the two groups at 7 days (prior to vaccination), 21 days (14 days post-vaccination and prior to challenge) and 31 days (10 days post-challenge) of age. The number of CD8(+) in spleen at 7 days of age and IgM(+) cells in bursa at 7, 21 and 31 days of age were significantly higher in ascorbic acid supplemented group (P<0.05). Production of IL-2 by splenocytes was higher as indicated by higher stimulation indices in ascorbic acid supplemented group. The number of anti-IBDV IgG antibody secreting cells in spleen at 21 and 31 days of age were significantly higher in ascorbic acid supplemented group (P<0.05). Dietary supplementation of ascorbic acid may ameliorate the immunosuppression caused by IBDV vaccination and improve humoral and cellular immune responses.

Animals↗

Antiangiogenic effects of S-nitrosocaptopril crystals as a nitric oxide donor.

Angiogenesis is the formation of new capillaries from preexisting vessels by migration and proliferation of endothelial cells, which produce a cellular signaling messenger, nitric oxide (NO). The purpose of the present study was to examine the effects of exogenous NO donors on angiogenesis by using a novel crystalline NO donor, S-nitrosocaptopril. The characteristic X-ray diffraction pattern of S-nitrosocaptopril was demonstrated for the first time. On primary capillary endothelial cells pretreated with vascular endothelium growth factor (VEGF), S-nitrosocaptopril (1-500 microM), but not captopril, produced a dose-dependent inhibition of endothelial proliferation. On chick embryos of entire living eggs, gelatin sponges adsorbed with VEGF were implanted on the embryo chorioallantoic membrane to promote vascular growth activity within the sponges. Addition of S-nitrosocaptopril crystals (0.1 mg) to the gelatin sponges markedly reduced vascular density around the sponges, whereas captopril did not inhibit neovascularization. The vascular hemoglobin content surrounding each of the gelatin sponges was determined as a confirmatory test. S-nitrosocaptopril, but not captopril, significantly decreased the hemoglobin content of the embryo tissues immediately surrounding the gelatin sponges. In conclusion, S-nitrosocaptopril exerts an inhibitory effect on angiogenesis. This newly discovered function of S-nitrosocaptopril appears to be governed by distinct structural NO moiety.

Angiotensin-Converting Enzyme Inhibitors↗

Ontogeny of the tectorotundal pathway in chicks (Gallus gallus): birthdating and pathway tracing study.

The avian tectorotundal system has been suggested as a homologue of the mammalian colliculopulvinar system. In the tectorotundal system, neurons of the stratum griseum centrale (SGC) of the optic tectum send their axons bilaterally to the nucleus rotundus (Rt). In transit to the Rt, the axons of the SGC neurons collateralize in the nuclei posteroventralis thalami (PV), subpretectalis (SP), and interstitiopretectosubpretectalis (IPS) of the tectothalamic tract (TT). The current study used birthdating and pathway-tracing methods to investigate the neurogenesis and time course of neuronal connections of the tectorotundal pathway in chicks during embryogenesis. By using tritiated thymidine autoradiography, we observed that the SGC neurons of the tectum were generated by embryonic days 3.0-5.5 (E3.0-E5.5), the Rt by E3.5-E5.0, and the nuclei of TT by E3.5-4.5. To trace the tectorotundal pathway, we injected cholera toxin B subunit (CTb) into the tectum, and the CTb-like immunoreactivity was examined. By E4.5-E5.5, some CTb-like immunoreactive (CTb-LI) axons terminated in the ipsilateral SP/IPS. By E6.0-E6.5, CTb-LI axon bundles were seen ipsilaterally in the TT. Increased numbers of labeled axons were seen terminating in the SP/IPS. By E7.0-E7.5, heavily labeled axons in the TT were observed with diffuse terminals in areas ventral to the presumptive Rt and PV. By E7.5-E8.0, the tectal axons innervated the ipsilateral Rt, in which some of the collaterals crossed the midline to the contralateral diencephalon. The crossed tectorotundal projection was seen first by E8.0-E8.5. Also, during this stage, a few CTb-LI collaterals terminated in the contralateral SP/IPS. Between E10 and E13, the pattern of bilateral tectorotundal projections became more regionalized, whereas labeling continued to increase in the SP/IPS. At E16, the labeling pattern of all tectorecipient structures resembled that of the hatchling. The current study revealed the temporal order of development of the tectorotundal pathway during embryogenesis. The SGC cells first innervate ipsilaterally the SP/IPS and then the Rt/PV. The schedule of the crossed tectorotundal connections coincides with the schedule of tectal projections onto the contralateral intrinsic nuclei of the TT. We conclude that E8.0 (+/- E0.5) is a critical stage for the development of the tectofugal pathway. Moreover, the current study provides important insights into the relative ontogeny of the mammalian tectofugal pathway.

Animals↗

An appraisal of liver and portal vein resection for hepatocellular carcinoma with tumor thrombi extending to portal bifurcation.

BACKGROUND: The role of surgical resection for hepatocellular carcinoma with tumor thrombi involving the major portal vein is controversial because of a high operative risk and poor prognosis. Previously, a resection was performed only when the tumor thrombi were limited to the first branch of the portal vein without extension to the portal bifurcation. HYPOTHESIS: Concomitant liver and portal vein resection may be beneficial in patients with hepatocellular carcinoma with tumor thrombi extending to portal bifurcation. DESIGN: Retrospective review. SETTING: University hospital, tertiary referral center. PATIENTS: Among 368 patients with hepatocellular carcinoma who underwent a curative resection, portal vein involvement occurred in 112 patients. Fifteen of the 112 patients underwent a concomitant liver and portal vein resection owing to extension of tumor thrombi to the portal bifurcation (group 1). The remaining 97 patients did not need portal vein resection (group 2). INTERVENTION: Surgical indications, procedures, and results of pathological examination of resected specimens were assessed in patients in group 1. The clinicopathological characteristics, operative morbidity and mortality, and operative results were compared between the 2 groups. MAIN OUTCOME MEASURES: Disease-free and actuarial survival rates. RESULTS: Intramural tumor infiltration was found at the site of thrombi adhesion to the portal vein cuff in 11 of 15 patients in group 1. Owing to patient selection bias, patients in group 1 were significantly younger and had better liver function and greater resected liver weight. The operative time, postoperative hospitalization, operative blood loss, amount of blood transfusion, and operative morbidity and mortality did not differ significantly between the 2 groups. The 5-year disease-free survival rates of groups 1 and 2 were 21.6% and 20.4% (P =.19), respectively, while the actuarial survival rates were 26. 4% and 28.5% (P =.33), respectively. CONCLUSION: Liver resection with partial resection of the portal vein is justified in selected patients with hepatocellular carcinoma with tumor thrombi extending to portal bifurcation.

Carcinoma, Hepatocellular↗

Surgical treatment for recurrent hepatocellular carcinoma with tumor thrombi in right atrium: using cardiopulmonary bypass and deep hypothermic circulatory arrest.

Tumor in the right atrium creates a life-threatening condition and should be removed immediately. A cirrhotic patient who had recurrent hepatocellular carcinoma (HCC) over remnant liver with tumor thrombi extending to inferior vena cava (IVC) and right atrium presented with impending congestive heart failure. The recurrent tumor and its thrombi were successfully resected en-bloc using cardiopulmonary bypass and hypothermic circulatory arrest. Although the patient's disease-free and actual survival time were only 6 months and 14 months, respectively, he was rescued from heart failure. This aggressive surgical strategy creates further possibility to treat such advanced HCC cases. Further investigations regarding adjuvant therapies in these circumstances, however, are necessary.

Adult↗

Proteomics of rat liver Golgi complex: minor proteins are identified through sequential fractionation.

The discovery of novel proteins resident to the Golgi complex will fuel our future studies of Golgi structure/function and provide justification for proteomic analysis of this organelle. Our approach to Golgi proteomics was to first isolate and characterize the intact organelle free of proteins in transit by use of tissue pretreated with cycloheximide. Then the stacked Golgi fraction was fractionated into biochemically defined subfractions: Triton X-114 insoluble, aqueous, and detergent phases. The aqueous and detergent phases were further fractionated by anion-exchange column chromatography. In addition, radiolabeled cytosol was incubated with stacked Golgi fractions containing proteins in transit, and the proteins bound to the Golgi stacks in an energy-dependent manner were characterized. All fractions were analyzed by two-dimensional (2-D) gel electrophoresis and identification numbers were given to 588 unique 2-D spots. Tandem mass spectrometry was used to analyze 93 of the most abundant 2-D spots taken from preparative Triton X-114 insoluble, aqueous and detergent phase 2-D gels. Fifty-one known and 22 unknown proteins were identified. This study represents the first installment in the mammalian Golgi proteome database. Our data suggest that cell fractionation followed by biochemical dissection of specific classes of molecules provides a significant advantage for the identification of low abundance proteins in organelles.

Animals↗

Proteomics reveal a link between the endoplasmic reticulum and lipid secretory mechanisms in mammary epithelial cells.

The synthesis and secretion of lipids by mammary epithelial cells is a highly ordered process that involves several distinct steps. Triacylglycerols are synthesized in the endoplasmic reticulum and incorporated into microlipid droplets which coalesce into cytoplasmic lipid droplets. These are vectorially transported to the apical plasma membrane where they are secreted into the milk surrounded by a membrane bilayer. The origin of this membrane as well as the mechanism by which cytoplasmic lipid droplets form and become surrounded by membrane is poorly understood. Proteomic analysis of the protein composition of milk fat globules and cytoplasmic lipid droplet has revealed that the endoplasmic reticulum is not only involved in the synthesis of the lipid but also potentially contributes to the membrane component of milk fat globules. The proteins identified suggest possible mechanisms of multiple steps during this process. Completion of the proteome of milk fat globule membranes and cytoplasmic lipid droplets will provide the necessary reporter molecules to follow and dissect the mechanisms of the sorting and ultimate secretion of cytoplasmic lipid droplets.

Animals↗

Benzalkonium chloride and gentamicin cause a leak in corneal epithelial cell membrane.

The purposes of this study are to characterize the pathophysiological effects of benzalkonium chloride and gentamicin on corneal epithelial cells and to determine the concentration dependent effect of these agents on membrane currents of these cells. Rabbit corneal epithelial cells were isolated and subdivided into small, medium and large cells according to their cell capacitance. Using whole cell clamp technique, potassium current of corneal epithelial cells was recorded. Transmembrane current was measured again after bathing in benzalkonium chloride 1, 3, 10, 30 and 100 micrometer ml(-1)for 3 min. The effect of gentamicin was tested at concentrations of 0.4, 1.0, 2.0, 4.0 and 10 mg ml(-1). Synergistic effect of gentamicin of the above mentioned concentrations in the presence of benzalkonium chloride 1 microgram ml(-1)was also measured. We found that small corneal epithelial cells had the highest depolarization-gated, outward potassium current density and large cells had the lowest current density, while medium cells had a current density in between. Benzalkonium chloride induced a concentration dependent increase in the leak current with increasing concentration from 1 to 100 microgram ml(-1). The increase of leak current in medium and large cells was less than that in the small cells. Gentamicin also caused a concentration dependent increase in leak current density from 0.4 to 10.0 mg ml(-1). The increase in leak current density was statistically significant when the concentration was 2.0 mg ml(-1)or higher in small corneal epithelial cells and 1.0 mg ml(-1)or higher in the medium and large cells. Benzalkonium chloride 1.0 microgram ml(-1)augmented the effect of gentamicin on epithelial cell membrane. The extent of enhancement was more prominent in larger than smaller cells. Using whole-cell clamp technique, we were able to determine the threshold concentration of gentamicin and benzalkonium chloride on the integrity of corneal epithelial cell membrane. The toxic action of both agents is mediated by an increase in leak current. We propose that the whole-cell clamp technique is a sensitive and useful tool in determining cytotoxic effects of various agents.

Animals↗

Premedication with dextromethorphan provides posthemorrhoidectomy pain relief.

PURPOSE: Previous studies have shown that N-methyl-D-aspartate receptor antagonists provide a preemptive analgesic effect in humans. This study was designed to examine whether premedication with dextromethorphan, an N-methyl-D-aspartate antagonist, also provided a preemptive analgesic effect that improved postoperative pain management. METHODS: Sixty patients who were American Society of Anesthesiologists status I and II scheduled for hemorrhoidectomy (modified Whitehead procedure) were included in the study. Patients were randomly assigned to the control and study groups. For the control group patients received chlorpheniramine maleate (20 mg), a component of the injection form of dextromethorphan, intramuscular injection 30 minutes before skin incision. In the study group dextromethorphan 40 mg containing 20 mg chlorpheniramine maleate (intramuscular) was given as premedication 30 minutes before skin incision. Pethidine (1 mg/kg, intramuscular) was given for pain relief as required postoperatively. The time to first pethidine injection, total pethidine consumption, worst pain score, and pethidine-related side effects were recorded for 48 hours postoperatively. RESULTS: The times to first pethidine injection (mean +/- standard error of the mean) were 5.2 +/- 3 and 19.6 +/- 6 hours in the control and study groups, respectively. Total pethidine consumption was 140 +/- 11.3 and 63.5 +/- 11.8 mg in the control and study groups. The worst visual analog scale pain scores were 7.4 +/- 0.2 and 5.6 +/- 0.3 in the control and study groups during the two-day observation. The numbers of patients who required pethidine injection were 29 and 20 in the control and study groups, respectively. Two patients suffered pethidine-related side effects, such as nausea, vomiting, dizziness, and headache, in the control group, and no patient complained of any side effect in the study group. CONCLUSION: We found that dextromethorphan premedication provided a preemptive analgesic effect, thus producing reduced postoperative pain and pethidine requirement and improved recovery from hemorrhoidectomy.

Adult↗

Tibial shaft malunion treated with reamed intramedullary nailing: a revised technique.

Thirty-seven consecutive adult tibial shaft malunions which had not undergone surgical treatment were prospectively treated with reamed intramedullary nailing. Indications for this treatment modality included a malunion of a tibial shaft which had only been conservatively treated, lesion level fitting for traditional or locked reamed intramedullary nail fixation, less than 2 cm shortening, and without evidence of deep infection at present. The malunions were treated with fibulotomy, closed wedge tibial osteotomy, open reaming of the marrow cavity, stable reamed intramedullary nail stabilization with or without supplementation, and cancellous bone grafting. Thirty-four (92%) patients were followed up for at least 1 year (range 1.0-4.3 years), and all achieved a solid union. The union period was 5.8+/-0.8 months. Complications included 2 (6%) patients with deep infection and 1 (3%) with cortical perforation. However, all 3 patients recovered completely after adequate management. In conclusion, a reamed intramedullary nail is an ideal instrument for tibial shaft malunions in indicated cases. Good exposure of the bony segments to ream the marrow cavity precisely can avoid cortical perforation. Gentle dissection of the soft tissues may lower the infection rate. Concomitant cancellous bone grafting can improve the union rate.

Adolescent↗