Late repair of the native pulmonary valve in patients with pulmonary insufficiency after surgery for tetralogy of Fallot

Pulmonary regurgitation developing late after tetralogy of Fallot repair is now recognized as a serious threat to the long-term welfare of these patients. This article summarizes our experience with 5 patients who underwent reoperations for treatment of severe pulmonary regurgitation after transannular patch repair of tetralogy of Fallot. In each case, the intraoperative findings revealed anatomy favorable for valve repair and enabled preservation of the native pulmonary valves.     

Comparison of plain radiographs with CT scan to evaluate interbody fusion following the use of titanium interbody cages and transpedicular instrumentation

The availability of lumbar interbody cages has fuelled renewed interest in interbody fusion. Despite this, there is no consensus regarding the best non-invasive method for evaluation of interbody fusion, especially where cages have been used. The purpose of this study was to determine whether high-quality thin-slice (1- to 3-mm) computed tomography (CT) scans allow proper evaluation of interbody fusion through titanium cages. Patients undergoing lumbar interbody fusion were prospectively evaluated with CT scan and plain radiographs 6 months following surgery. These images were blindly and independently evaluated by a consultant radiologist and a spine research fellow, for bridging bony trabeculation both through and surrounding the cages as well as for changes at the cage endplate interface. Fifty-three patients (156 cages) undergoing posterior lumbar interbody fusion using titanium interbody cages were evaluated. Posterior elements were used to pack the cages and no graft was packed outside the cages. The outcome data were analysed using the Kappa co-efficient and chi-squared analysis. On CT scan, both observers noted bridging trabeculation in 95% of the cages (Kappa 0.85), while on radiographs this was present in only 4% (Kappa 0.74). Both observers also identified bridging trabeculation surrounding the cages on CT scan in 90% of cages (Kappa 0.82), while on the radiographs this was 8% (Kappa 0.86). Radiographs also failed to demonstrate all the loose cages. The results of the study show that high-quality CT scans show images suggesting bridging bony trabeculae following the use of titanium interbody cages. They also appear to show consistent bone outside the cages in spite of no bone graft having been used, and they appear to be better than plain radiographs in the early detection of cage loosening.     

Quantitative trait loci for hypercalciuria in a rat model of kidney stone disease

Hypercalciuria is the most common risk factor for kidney stones and has a recognized familial component. The genetic hypercalciuric stone-forming (GHS) rat is an animal model that closely resembles human idiopathic hypercalciuria, with excessive intestinal calcium absorption, increased bone resorption, and impaired renal calcium reabsorption; overexpression of the vitamin D receptor (VDR) in target tissues; and calcium nephrolithiasis. For identifying genetic loci that contribute to hypercalciuria in the GHS rat, an F2 generation of 156 rats bred from GHS female rats and normocalciuric WKY male rats was studied. The calcium excretion was six- to eightfold higher in the GHS female than in the WKY male progenitors. Selective genotyping of those F2 rats with the highest 30% and lowest 30% rates of calcium excretion was performed, scoring 98 markers with a mean interval of 23 cM across all 20 autosomes and the X chromosome. With the use of strict criteria for significance, significant linkage was found between hypercalciuria and a region of chromosome 1 at D1Rat169 (LOD, 2.91). Suggestive linkage to regions of chromosomes 4, 7, 10, and 14 was found. The proportion of phenotypic variance contributed by the region on chromosome 1, with appropriate adjustments, was estimated to be 7%. Candidate genes encoding the VDR and the calcium-sensing receptor were localized to regions on rat chromosomes 7 and 11, respectively, but the suggestive quantitative trait locus on chromosome 7 was not in the region of the VDR gene locus. Identification of genes that contribute to hypercalciuria in this animal model should prove valuable in understanding idiopathic hypercalciuria and kidney stone disease in humans.     

Perillyl alcohol mediated radiosensitization via augmentation of the Fas pathway in prostate cancer cells

BACKGROUND: The management of hormone-insensitive locally advanced prostate cancer is difficult and complex and there is an urgent need for the development of effective chemotherapeutic agents intended for combination with currently available treatment modalities. METHODS: The present paper demonstrates the effectiveness of the monoterpene perillyl alcohol (POH) as potent radiosensitizer on DU145 and PC3 cell lines by performing clonogenic survival assays, cycle analysis, and assays to detect viability, apoptosis, and Fas receptor/ligand by flow cytometry. RESULTS: POH pretreatment resulted in a dose dependent sensitization to kill cell by radiation. Furthermore, POH treatment induced a transient G(2)/M arrest, enhanced the expression of the membrane bound form of the Fas ligand and sensitized the cells to Fas mediated apoptosis. CONCLUSIONS: The unique manner of radiosensitization in addition to its low toxicity profile makes POH a promising new agent for preclinical evaluation as a potential radiosensitizer in the treatment of prostate cancer.     

Voxel-based diffusion tensor magnetic resonance imaging evaluation of low-grade hepatic encephalopathy

PURPOSE: To quantify the changes in brain water diffusivity in hepatic encephalopathy (HE) associated with cirrhosis using diffusion tensor imaging (DTI) and to correlate with neuropsychological (NP) scores. MATERIALS AND METHODS: DTI was performed in 14 patients with low-grade HE and age/gender-comparable 16 healthy controls. Whole brain mean diffusivity (MD) and fractional anisotropy (FA) maps were calculated, normalized to common space, smoothed, and compared voxel-by-voxel between groups using analysis of covariance with age included as a covariate. The average MD and FA values were also calculated from individual subjects for selected brain regions and correlated with the neuropsychological scores. RESULTS: Patients with HE showed increased MD in the cortical gray and white matter and the internal capsule. Less extensive brain regions with decreased FA were observed in the bilateral frontal and occipital white matter. MD values from the corpus callosum correlated inversely with several NP scores among HE patients and controls. Positive correlations were observed with FA values and cognitive scores. CONCLUSION: Voxel-based DTI analysis showed widespread brain regions with increased MD values, indicating enhanced water content and decreased FA in cirrhotic patients with HE. The MD and FA values from selected regions correlated with the NP scores.     

Early experience with the Levitronix Centrimag device for extra-corporeal membrane oxygenation following lung transplantation

Extra-corporeal membrane oxygenation (ECMO) is accepted as a salvage therapy to treat life-threatening complications following lung transplantation such as primary graft dysfunction, acute rejection or airway dehiscence. Levitronix Centrimag^® (Levitronix LLC, Waltham, MA) is a centrifugal pump that consists of a magnetically levitated bearing-less rotor designed to reduce blood friction. ECMO using the Levitronix Centrimag^® pump may be an ideal medium-term support for lung transplant recipients suffering these serious complications. We describe our early experience of using ECMO with Levitronix Centrimag^® device and the Hilite hollow fibre membrane oxygenator (Medos Hilite^® LT, Medos Medizintechnik AG) in three cases following lung transplantation. The device is technically easy to implant and manage with a low complication rate on minimal anticoagulation.     

Radiation exposure from fluoroscopy during fixation of hip fracture and fracture of ankle: Effect of surgical experience

Background:

Over the years, there has been a tremendous increase in the use of fluoroscopy in orthopaedics. The risk of contracting cancer is significantly higher for an orthopedic surgeon. Hip and spine surgeries account for 99% of the total radiation dose. The amount of radiation to patients and operating surgeon depends on the position of the patient and the type of protection used during the surgery. A retrospective study to assess the influence of the radiation exposure of the operating surgeon during fluoroscopically assisted fixation of fractures of neck of femur (dynamic hip screw) and ankle (Weber B) was performed at a district general hospital in the United Kingdom.

Materials and Methods:

Sixty patients with undisplaced intertrochanteric fracture were included in the hip group, and 60 patients with isolated fracture of lateral malleolus without communition were included in the ankle group. The hip and ankle groups were further divided into subgroups of 20 patients each depending on the operative experience of the operating surgeon. All patients had fluoroscopically assisted fixation of fracture by the same approach and technique. The radiation dose and screening time of each group were recorded and analyzed.

Results:

The radiation dose and screening time during fluoroscopically assisted fixation of fracture neck of femur were significantly high with surgeons and trainees with less than 3 years of surgical experience in comparison with surgeons with more than 10 years of experience. The radiation dose and screening time during fluoroscopically assisted fixation of Weber B fracture of ankle were relatively independent of operating surgeon''s surgical experience.

Conclusion:

The experience of operating surgeon is one of the important factors affecting screening time and radiation dose during fluoroscopically assisted fixation of fracture neck of femur. The use of snapshot pulsed fluoroscopy and involvement of senior surgeons could significantly reduce the radiation dose and screening time.     

Early results for below-knee bypasses using Distaflo

In patients who require lower extremity revascularization, prosthetic graft is a reasonable alternative in the absence of a suitable autologous vein conduit. However, prosthetic bypass grafts have limited patency, especially for infrageniculate reconstruction. Polytetrafluoroethylene grafts were geometrically modified at the distal end to increase their patency. The authors reviewed their experience with the Distaflo graft in patients who required lower extremity below-knee popliteal and tibial bypasses when no suitable autologous vein conduit was available. Chart review was conducted of the 57 patients who underwent 60 lower extremity bypasses over a 3-year period between June 2003 and April 2006. Twenty-four revascularizations were constructed to the tibial outflow sites, whereas the remaining grafts were placed to the below-knee (28) and above-knee (8) popliteal artery, respectively. Study endpoints were primary, assisted primary, secondary patency, and limb salvage at the time of follow-up. Distaflo bypass was performed at the infrageniculate level in 86.7% of cases (28 below-knee popliteal, 24 tibial). Mean follow-up time was 12 months (range, 0.5-37.5 months). At 1 year, primary, assisted primary, and secondary patencies and limb salvage rates for below-knee popliteal bypasses were 83.5%, 89.5%, 94.7%, and 94.4%, respectively. Primary, assisted primary, and secondary patencies and limb salvage rates for tibial bypasses were 44.4%, 44.4%, 63.2%, and 74.9%, respectively. Distaflo precuffed graft is a good alternative conduit for below-knee popliteal and tibial lower extremity reconstructions in the absence of an autologous vein and appears to have promising early patency and limb salvage rates even when used for tibial bypasses.     

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.     

Retroperitoneal robotic renal surgery: technique and early results

We describe a robotic retroperitoneal approach to renal surgery, optimized in porcine and cadaveric models, and applied to human patients. A retroperitoneal approach for robotic kidney surgery was developed in nonsurvival porcine and a fresh cadaver models, and then utilized in ten patients (three partial nephrectomy, three radical nephrectomy, two simple nephrectomy, one pyeloplasty, one cryoablation). Retroperitoneal access was successfully achieved for robotic renal procedures in six pigs and a human cadaver. Ten human patients (mean age 56 years, range 36–72 years) then underwent a successful retroperitoneal approach for robotic renal surgery. Mean console time was 166 (120–300) min. Mean blood loss was 82 (50–100) ml and average hospital stay was 2.6 (1–5) days. Pathology demonstrated clear cell renal cell carcinoma (four), papillary renal cell carcinoma (two), and xanthogranulomatous pyelonephritis (two). One patient with xanthogranulomatous pyelonephritis required open conversion for failure to progress due to dense adhesions. A retroperitoneal approach is a safe and feasible alternative to a transperitoneal approach for robotic renal surgery, including radical nephrectomy, partial nephrectomy, pyeloplasty, and cryoablation. M. N. Patel and S. A. Kaul contributed equally to this work.