Off-pump coronary artery grafting in patients with left main coronary artery disease

BACKGROUND: Left main coronary artery disease (LMCD) is considered a relative contraindication to off-pump coronary artery bypass (OPCAB) grafting. This study evaluates the safety and feasibility of OPCAB in these patients compared to an on-pump group (cardiopulmonary bypass, CPB) with LMCD. METHODS: Between January 2000 and July 2002, 95 patients with left main coronary artery stenosis >50% underwent coronary revascularization. Seventy-three unselected patients underwent OPCAB and 22 underwent revascularization using CPB. The techniques used for OPCAB included the use of deep traction sutures in the posterior pericardium and stabilizers to expose the distal coronary targets. Intraluminal coronary shunts were routinely used during construction of the anastomoses. Variables were analyzed using a Student's paired t-test with statistical significance defined as p < 0.05. RESULTS: The mean age in the OPCAB group was 59.9 years and the CPB group 61.8 years (p = 0.54). There were 56 males (77%) in the OPCAB and 18 (82%) in the CPB groups. Mean preoperative left ventricular ejection fraction (LVEF) was 40.3% in OPCAB and 47.3% in CPB (p = 0.015). Average number of grafts was 3.1 in OPCAB and 4.1 in CPB (p = 0.0038). There were no conversions to CPB in those patients initially chosen to undergo OPCAB. There were no early deaths in OPCAB. There was one death in CPB. Mean hospital length of stay was 6.9 days for OPCAB and 9.1 for CPB (p = 0.0159). CONCLUSIONS: Patients with LMCD can undergo OPCAB grafting safely and effectively despite reduced LVEF. LMCD should no longer be seen as a contraindication to perform OPCAB grafting.     

Functional outcome of salvage of residual and recurrent deformities of clubfoot with Ilizarov technique

Relapse may occur in severe clubfeet deformities whether treated surgically or nonsurgically. In this study, we evaluate the results of correction of residual and recurrent congenital clubfoot using soft tissue distraction or osteotomy using the Ilizarov external fixation system. This study included 35 feet in 28 patients who were treated between 1999 and 2007. Of these 16 feet in 13 patients with an average age of 13.7 years (range from 11 to 29 years) were treated by percutaneous calcaneal V-osteotomy and gradual correction by the Ilizarov method. Nineteen feet in 15 patients with an average age 10.5 years (range from 4 to 22 years) were treated by soft tissue distraction by the Ilizarov technique. The mean average follow up period was 5.6 years (range from 1 to 8 years). At the time of fixator removal, a plantigrade foot was achieved in 30 feet. Mild residual varus and equinus deformities were present in five feet.At the final follow foot pressure measurement showed recurrent or residual deformity in 10 feet (7 treated by osteotomy and 3 treated by soft tissue distraction). Recurrence may occur with both techniques, depending on many factors such as bone morphology, the number of the pervious operations and the degree of stiffness of the foot prior to the operation.     

Effect of chitosan particles and dexamethasone on human bone marrow stromal cell osteogenesis and angiogenic factor secretion

Chitosan is a polysaccharide scaffold used to enhance cartilage repair during treatments involving bone marrow stimulation, and it is reported to increase angiogenesis and osteogenesis in vivo. Here, we tested the hypotheses that addition of chitosan particles to the media of human bone marrow stromal cell (BMSC) cultures stimulates osteogenesis by promoting osteoblastic differentiation and by favoring the release of angiogenic factors in vitro. Confluent BMSCs were cultured for 3 weeks with 16% fetal bovine serum, ascorbate-2-phosphate and disodium β-glycerol phosphate, in the absence or presence of dexamethasone, an anti-inflammatory glucocorticoid commonly used as an inducer of BMSC osteoblast differentiation in vitro. As expected, dexamethasone slowed cell division, stimulated alkaline phosphatase activity and enhanced matrix mineralization. Added chitosan particles accumulated intra- and extracellularly and, while not affecting most osteogenic features, they inhibited osteocalcin release to the media at day 14 and interfered with mineralized matrix deposition. Interestingly, dexamethasone promoted cell attachment and suppressed the release and activation of matrix metalloprotease-2 (MMP-2). While chitosan particles had no effect on the release of angiogenic factors, dexamethasone significantly inhibited (p < 0.05 to p < 0.0001) the release of vascular endothelial growth factor (VEGF), granulocyte-macrophage colony stimulating factor (GM-CSF), tumor necrosis factor-alpha (TNF-α), interleukins 1β, 4, 6, and 10 (IL-1β, IL-4, IL-6, IL-10), and a host of other inflammatory factors that were constitutively secreted by BMSCs. These results demonstrate that chitosan particles alone are not sufficient to promote osteoblast differentiation of BMSCs in vitro, and suggest that chitosan promotes osteogenesis in vivo through indirect mechanisms. Our data further show that continuous addition of dexamethasone promotes osteoblastic differentiation in vitro partly by inhibiting gelatinase activity and by suppressing inflammatory cytokines which result in increased cell attachment and cell cycle exit.     

Remodeling of murine intrasynovial tendon adhesions following injury: MMP and neotendon gene expression

Tendon injury frequently results in the formation of adhesions that reduce joint range of motion. To study the cellular, molecular, and biomechanical events involved in intrasynovial tendon healing and adhesion formation, we developed a murine flexor tendon healing model in which the flexor digitorum longus (FDL) tendon of C57BL/6 mice was transected and repaired using suture. This model was used to test the hypothesis that murine flexor tendons heal with differential expression of matrix metalloproteases (MMPs), resulting in the formation of scar tissue as well as the subsequent remodeling of scar and adhesions. Healing tendons were evaluated by histology, gene expression via real-time RT-PCR, and in situ hybridization, as well as biomechanical testing to assess the metatarsophalangeal (MTP) joint flexion range of motion (ROM) and the tensile failure properties. Tendons healed with a highly disorganized fibroblastic tissue response that was progressively remodeled through day 35 resulting in a more organized pattern of collagen fibers. Initial repair involved elevated levels of Mmp-9 at day 7, which is associated with catabolism of damaged collagen fibers. High levels of Col3 are consistent with scar tissue, and gradually transition to the expression of Col1. Scleraxis expression peaked at day 7, but the expression was limited to the original tendon adjacent to the injury site, and no expression was present in granulation tissue involved in the repair response. The MTP joint ROM with standardized force on the tendon was decreased on days 14 and 21 compared to day 0, indicating the presence of adhesions. Peak expressions of Mmp-2 and Mmp-14 were observed at day 21, associated with tendon remodeling. At day 28, two genes associated with neotendon formation, Smad8 and Gdf-5, were elevated and an improvement in MTP ROM occurred. Tensile strength of the tendon progressively increased, but by 63 days the repaired tendons had not reached the tensile strength of normal tendon. The murine model of primary tendon repair, described here, provides a novel mechanism to study the tendon healing process, and further enhances the understanding of this process at the molecular, cellular, and biomechanical level. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 833–840, 2009     

Left ventricular systolic and diastolic function and carotid intima-media thickness in pediatric dialysis patients

Background  Cardiovascular complications are common in patients with end-stage renal disease (ESRD). We aimed to investigate left ventricular (LV) function and carotid intima-media thickness (cIMT) in children and adolescents with ESRD. Methods  This study included 38 ESRD patients (15 hemodialysis and 23 peritoneal dialysis) and 17 age- and sex-matched healthy subjects. Results  The ESRD patients had significantly lower mean mitral E/A ratio, and higher left ventricular mass index (LVMI) and cIMT than the control group. Compared with PD patients, HD patients had worse LV diastolic function. In stepwise linear regression analysis, LVMI (P = 0.043) and hemoglobin (P = 0.015) turned out to be independent variables for predicting diastolic dysfunction (reduced E/A ratio), and the only significant predictor of cIMT was indexed diastolic blood pressure (DBP) (P = 0.035). Conclusion  Cardiovascular structure and function abnormalities are also common in pediatric dialysis patients, as in adults. Furthermore our data indicated that hemodialysis was disadvantageous for preserving LV diastolic function as compared with peritoneal dialysis.     

Painful neuroma requiring surgical excision after lower limb amputation caused by landmine explosions

This article reports an analysis of 75 consecutive lower limb amputees who developed painful neuroma requiring surgical excision after lower limb amputation following landmine explosions. This retrospective study analyses the results of 75 patients who were treated for painful neuroma after lower limb amputation following landmine explosions between the years 2000 and 2006. The average time period from use of prosthesis to start of symptoms suggesting neuroma was 9.6 months. The average time period from start of pain symptoms to neuroma surgery was 7.8 months. All clinically proven neuromas were surgically resected. In the mean follow-up of 2.8 years, all patients were satisfied with the end results and all were free of any pain symptoms. Painful stump with clinical diagnostic findings of neuroma described above may be regarded as neuroma without requiring any further imaging modalities and is an indication for surgery if conservative measures fail.     

Use of antibiotic cement-impregnated intramedullary nail in treatment of infected non-union of long bones

Background:

In cases with infected non-union, the primary step is eradication of the infection before attempting to achieve union. Release of antibiotics from the bone cement at a high concentration and its penetration to the surrounding tissues, including cortical and cancellous bone, prompted the use of antibiotic cement in the control of bone infection. The aim of this study is to summarize our experience with the use of antibiotic cement-impregnated intramedullary nail (ACIIN) for control of infection in cases of infected non-union with bone defect.

Materials and Methods:

We prospectively studied 25 cases of infected non-union (23 femora and two tibiae). There were 24 males and one female, with the mean age being 33 years (range, 21–58 years). All patients had high-velocity road traffic accidents except one patient who had farmland injury. There were seven closed fractures, one grade I compound, two grade II compound fractures, five grade IIIA compound fractures, and 10 grade IIIB compound fractures. ACIIN was used in all cases after adequate debridement. Patients were classified according to the amount of bone defect present after debridement: group 1 with bone defect <4 cm (n=13), group 2 with bone defect ≥4–<6 cm (n=7), and group 3 with bone defect ≥6 cm (n=5). Infection control was judged on the basis of discharge through the wound and laboratory parameters. All patients were followed-up, with an average follow-up time of 29 months (range, 18–40 months). The mean duration of retention of the intramedullary rod was 8 weeks (range, 6–12 weeks).

Results:

In group 1, all cases achieved infection control, with three patients achieving bone union without any need of secondary procedure. In group 2, all cases achieved infection control but the time taken was significantly longer than for group 1 (P value 0.0002). All the cases required a secondary procedure in the form of either interlocking intramedullary nailing with iliac crest bone graft or Ilizarov ring fixator application to achieve union. None of the cases in group 3 achieved infection control.

Conclusion:

ACIINs are useful for infection control in cases of infected non-union with bone defect <6 cm. In cases with defect >6 cm, other alternatives should be used.     

The effect of low-intensity pulsed ultrasound on callus maturation in tibial distraction osteogenesis

Callus distraction is currently the most popular method of bone lengthening. Prolonged treatment time is one of its major problems. In this study, we investigated the effect of low-intensity pulsed ultrasound on tibial distraction osteogenesis. We managed 20 patients with tibial defects ranging from 5 cm to 8 cm with distraction osteogenesis using the Ilizarov external fixator. After the completion of distraction, ten patients received daily 20 min of low-intensity pulsed ultrasound stimulation (30 mW/cm²) onto the bone lengthening site (group A) while rigid fixation was maintained in the remaining patients (group B). All patients were followed with weekly radiographs to determine the formation of an external cortex and an intramedullary canal, at which time the fixator was removed. The mean healing index in group A was 30 (27–36) days/cm while it was 48 (42–75) days/cm in group B. In group B, one patient failed to consolidate the regenerated bone. Low-intensity pulsed ultrasound stimulation is highly effective in achieving maturation of bone and reducing time of distraction osteogenesis.

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Résumé La distraction du cal est la méthode dallongement de los la plus populaire actuellement. La longueur du traitement est un de ses problèmes majeurs. Nous avons étudié leffet des ultrasons pulsés de basse intensité sur lostéogenèse dans la distraction tibiale.Nous avons traité 20 malades présentant un défaut tibial de 5 à 8 centimètres avec ostéogenèse de distraction utilisant un fixateur externe dIlizarov. Après lachèvement de la distraction 10 malades ont reçu quotidiennement une stimulation par ultrasons (30 mW/cm²) sur lemplacement de lallongement osseux pendant 20 minutes (groupe A), pendant que la fixation rigide était maintenue pour le restant des malades (groupe B). Tous les malades ont été suivis avec des radiographies hebdomadaires pour déterminer la formation dun cortex périphérique et dun canal intramédullaire au moment ou le fixateur a été enlevé. Lindex de consolidation moyen dans le groupe A était 30 (27–36) jours/cm pendant quil était 48 (42–75) jours/cm dans le groupe B. Dans le groupe B un malade na pas consolidé los régénéré. La stimulation par ultrasons pulsés de basse intensité est très efficace pour favoriser la maturation osseuse et réduire le temps dostéogenèse dans la distraction.

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None of the authors received financial support for this study.     

Cortical brain mapping of peripheral nerves using functional magnetic resonance imaging in a rodent model

The regions of the body have cortical and subcortical representation in proportion to their degree of innervation. The rat forepaw has been studied extensively in recent years using functional magnetic resonance imaging (fMRI), typically by stimulation using electrodes directly inserted into the skin of the forepaw. Here we stimulate the nerve directly using surgically implanted electrodes. A major distinction is that stimulation of the skin of the forepaw is mostly sensory, whereas direct nerve stimulation reveals not only the sensory system but also deep brain structures associated with motor activity. In this article, we seek to define both the motor and sensory cortical and subcortical representations associated with the four major nerves of the rodent upper extremity. We electrically stimulated each nerve (median, ulnar, radial, and musculocutaneous) during fMRI acquisition using a 9.4-T Bruker scanner (Bruker BioSpin, Billerica, MA). A current level of 0.5 to 1.0 mA and a frequency of 5 Hz were used while keeping the duration constant. A distinct pattern of cortical activation was found for each nerve that can be correlated with known sensorimotor afferent and efferent pathways to the rat forepaw. This direct nerve stimulation rat model can provide insight into peripheral nerve injury.