On the design of a macro-micro parallel manipulator for cochlear microrobot operations.

BACKGROUND: The method of stem cell transfer to narrow cochlear canals in vivo to generate hair cells is still an unclear operation. Thus, the development of any possible method that will ensure the usage of medical microrobots in small cochlear workspaces is a challenging procedure. METHODS: The current study tries to introduce a macro-micro manipulator system composed of a 6-DoF industrial serial manipulator as a macro manipulator and a proposed 5-DoF parallel manipulator with dual end effectors as a micro manipulator carrying permanent magnets for tetherless microrobot actuation inside the cochlea. RESULTS: Throughout the study, structural synthesis and kinematic analysis of the proposed micro manipulator were introduced. A prototype of the manipulator was manufactured and its hardware verification procedures were carried out using motion capture cameras and surgical navigation registration methodologies. CONCLUSIONS: Following motion training, the assembled macro-micro manipulator was successfully utilised to actuate a microrobot placed inside a manufactured cochlea mockup model.

Retractor in retractor technique.

Placing retractor and stabilization devices during open heart surgery can be difficult in obese patients due to extremely short neck and excessive breast tissue. Off-pump coronary bypass operations in these patients can be particularly technically demanding. To overcome this difficulty, we have used two retractors concomitantly. The first retractor is placed to the edges of sternum and the second one is placed into this first retractor. This maneuver ensures an extra height, and placing stabilization devices in this second retractor is relatively easy. Thus, we suggest that adding this maneuver will facilitate off-pump coronary bypass operations.

Characterization​ and ​analysis of ​m​otion ​m​echanism​ of electroactive​ chitosan-based actuator.

In order to analyze the bending mechanism of the electroactive​ chitosan-based actuator, different amounts of poly(diallyldimethylammonium chloride) (PDAD) were incorporated in chitosan solution. The effects of PDAD concentration on electromechanical performance of chitosan actuator were investigated under various excitation voltages. With the incorporation of PDAD into chitosan solution, crosslinked chitosan film acts as an actuator showing a considerable displacement behavior. However it can be noted that higher incorporation of PDAD into chitosan solution decreased the performance of the actuators. Thermal, viscoelastic, and crystallographic properties of the chitosan films were examined by thermogravimetric analysis, dynamic mechanical analysis, and X-ray diffraction analysis, respectively. The effect of incorporation of PDAD in chitosan-based film on morphological properties of chitosan film was determined by scanning electron microscopy. It was observed that the films involving PDAD have larger pore size than the PDAD free film.

The Effect of Transdermal Testosterone Administration on Lower Urinary Tract Symptoms and Erectile Dysfunction: A Prospective, Randomized, Placebo-Controlled Trial.

OBJECTIVE: This study aimed to evaluate the effects of transdermal testosterone administration on lower urinary tract symptoms (LUTS) and erectile dysfunction (ED). MATERIALS AND METHOD: Sixty-two male patients with Ageing Male Symptom Questionnaire (AMS-Q) scores over 27 and a total serum testosterone level below 350 ng/dl (12.1 nmol/l) who presented to our urology clinic with complaints of LUTS and ED, were enrolled in this study. Uroflowmetry and the International Prostate Symptom Scale were used to evaluate the severity of LUTS. The International Index of Erectile Function was used to detect the severity of ED. In addition, the AMS-Q was used to quantify the severity of hypogonadism. We randomly divided patients into 2 groups. Thirty-one patients in the first group had transdermal testosterone administered at a daily dose of 50 mg (a sachet of 5 g) on the skin for 3 months. In the second group, 31 patients had a placebo administered for 3 months. The scales were recompleted based on interviews and uroflowmetry was repeated during checks of the patients performed in the first and third months. RESULTS: We detected a decrease in AMS-Q scores and an increase in maximum uroflow rate values and the International Index of Erectile Function scores in the first group compared with the placebo group. Although a decrease was detected in post-treatment International Prostate Symptom Scale scores in the first group, it was not regarded as statistically significant. CONCLUSION: This study revealed that testosterone replacement therapy is effective in improving LUTS and ED symptoms.

Expression of maspin in testis tumors with germ cells andits relation with angiogenesis factors.

BACKGROUND/AIM: We aimed to evaluate the importance of maspin expression in testicular tumors with germ cells, its effect on prognosis, and the relation with angiogenesis factors. MATERIALS AND METHODS: The paraffin blocks of the orchiectomy materials of 32 patients who had undergone orchiectomy due to testicular tumors were taken within the scope of the study. The specimens of the cases included in the study group were reexamined under light microscope. RESULTS: While just one maspin-positive sample was found in the seminoma cases, maspin stained positively in 6 of the nonseminoma germ cell tumors (NSGCTs). No statistical difference was found between maspin and tumor stage, size, alpha fetoprotein values, vascular endothelial growth factor, Ki-67, and CD31. A statistically positive correlation was only determined between maspin and p53 (P < 0.001). CONCLUSION: Maspin protein, whose expression in some tumors is accepted as a poor prognostic factor, is also expressed in testicular tumors with germ cells. However, according to our study, it is difficult to say whether this protein is a favorable or poor prognostic factor in testicular tumors and to understand how the effect mechanism works. The positive correlation between maspin and p53 in the NSGCTs makes us think that maspin might have displayed an effect on the p53 pathway.

Patient-prosthesis mismatch increases the mean platelet volume in patients with aortic valve replacement.

PURPOSE: Patient-prosthesis mismatch (PPM) is defined when the ratio of the effective orifice area of the normally functioning prosthetic valve to the body surface area of the patient is <0.85 cm(2)/m(2). The aim of this study was to assess the measurements of the mean platelet volume (MPV) as an indicator of platelet activation in patients with PPM. METHODS: A total of 109 patients with isolated aortic valve replacement (AVR) procedures with a mechanical prosthesis and a control group from a normal population of 102 people compatible in terms of age and sex were chosen for the study. The AVR group was subdivided into a PPM group (n = 41) and non-PPM group (n = 68). All patients and control participants underwent echocardiographic examinations, with simultaneous measurements of the serum MPV values. RESULTS: The MPV measurements were significantly higher in the patients with AVR compared to the control group (8.97 ± 0.93 vs. 8.26 ± 0.14, p < 0.001). Higher results were also obtained in the patients with PPM compared to the non-PPM group (9.36 ± 0.61 vs. 8.73 ± 1.01, p < 0.001). The platelet counts were found to be similar in both groups (p > 0.05). CONCLUSIONS: We have herein shown that the PPM patients had a significantly higher MPV compared to the patients with AVR without PPM and healthy subjects.

Single-centre experience with perioperative use of intraaortic balloon pump in cardiac surgery.

BACKGROUND: Intraaortic balloon pump (IABP) is frequently used in cardiac surgery in order to prevent or treat low cardiac output syndrome. Although being widely used and forming the first line therapy in these haemodynamically unstable patients despite maximal medication, optimal timing for IABP insertion is still discussed. This retrospective study evaluates hospital outcomes of patients receiving IABP at preoperative, intraoperative and postoperative periods during cardiac surgery. MATERIALS AND METHODS: Between 2006 and 2012, 2196 patients underwent open cardiac surgery in our centre. IABP was used in 121 (5.4%) patients. Nine patients had preoperative IABP insertion, 76 patients (62.8%) had intraoperative insertion to ease weaning from cardiopulmonary bypass, and 36 patients (29.8%) had postoperative insertion in the intensive care unit mainly due to refractory haemodynamic instability. Hospital outcomes of these 121 patients were analysed retrospectively. RESULTS: The majority of the patients were male (men 89, 73.6% and women 32, 26.4%; mean age was 65.9±11.5 years). Among the cohort 87 (71.9%) underwent isolated coronary artery bypass surgery (CABG) and the rest (34 patients, 28.1%) were operated for valve disease with/without CABG or for CABG with carotid endarterectomy, left ventricular aneurysm repair, post myocardial infarction ventricular septal defect or pathologies involving ascending aorta. The overall hospital mortality of the whole cohort was 27.3%. Mortality rates according to IABP timing were 33.3%, 19.7% and 41.7% for pre, intra and postoperative insertion, respectively. Logistic regression analysis identified female gender, low ejection fraction (<30%), complex surgery and postoperative insertion as risk factors for mortality. CONCLUSION: IABP insertion timing in cardiac surgery is crucial and many reports advocate early insertion since patient outcomes are poor for late insertions. This single centre study also confirms that the least favourable results are among patients with postoperative IABP insertion.

Comparison of original EuroSCORE, EuroSCORE II and STS risk models in a Turkish cardiac surgical cohort.

OBJECTIVES: The aim of this study was to compare additive and logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE), EuroSCORE II and the Society of Thoracic Surgeons (STS) models in calculating mortality risk in a Turkish cardiac surgical population. METHODS: The current patient population consisted of 428 patients who underwent isolated coronary artery bypass grafting (CABG) between 2004 and 2012, extracted from the TurkoSCORE database. Observed and predicted mortalities were compared for the additive/logistic EuroSCORE, EuroSCORE II and STS risk calculator. The area under the receiver operating characteristics curve (AUC) values were calculated for these models to compare predictive power. RESULTS: The mean patient age was 74.5 ± 3.9 years at the time of surgery, and 35.0% were female. For the entire cohort, actual hospital mortality was 7.9% (n = 34; 95% confidence interval [CI] 5.4-10.5). However, the additive EuroSCORE-predicted mortality was 6.4% (P = 0.23 vs observed; 95% CI 6.2-6.6), logistic EuroSCORE-predicted mortality was 7.9% (P = 0.98 vs observed; 95% CI 7.3-8.6), EuroSCORE II- predicted mortality was 1.7% (P = 0.00 vs observed; 95% CI 1.6-1.8) and STS predicted mortality was 5.8% (P = 0.10 vs observed; 95% CI 5.4-6.2). The mean predictive performance of the analysed models for the entire cohort was fair, with 0.7 (95% CI 0.60-0.79). AUC values for additive EuroSCORE, logistic EuroSCORE, EuroSCORE II and STS risk calculator were 0.70 (95% CI 0.60-0.79), 0.70 (95% CI 0.59-0.80), 0.72 (95% CI 0.62-0.81) and 0.62 (95% CI 0.51-0.73), respectively. CONCLUSIONS: EuroSCORE II significantly underestimated mortality risk for Turkish cardiac patients, whereas additive and logistic EuroSCORE and STS risk calculators were well calibrated.

Reduction of iodinated contrast load with the renal artery catheterization technique during endovascular aortic repair.

PURPOSE: We aimed to present our clinical experience with the renal artery catheterization (RAC) technique, which reduces the volume of intra-arterial contrast media (ICM) used during endovascular aortic repair (EVAR), and describe the short-term results of this technique. MATERIALS AND METHODS: We retrospectively evaluated 16 patients (15 males and one female) who underwent EVAR between March 2011 and February 2012 using the RAC technique for an abdominal aortic aneurysm. A Simmons-1 catheter was preferred for renal artery cannulation. The mean age of the patients at the time of treatment was 70 years (range, 61-82 years). Fifteen cases were fusiform aneurysms, and one case was a saccular aneurysm. Creatinine and estimated glomerular filtration rate (eGFR) values were recorded before the procedure and during the first 72 hours postprocedure. RESULTS: Bifurcated stent grafts were implanted with 100% procedural success using the RAC technique. The inferiorly positioned renal artery was cannulated with a Simmons-1 catheter in the first five patients, and was maintained at the level of the renal artery orifice in the remaining patients. The mean volume of the ICM used was 47 mL (range, 23-83 mL). The creatinine and eGFR values were not significantly different between the pre- and postoperative periods (P > 0.05). CONCLUSION: Reducing the volume of ICM used during EVAR is critical for protecting renal function. The RAC technique is a safe and effective method in appropriate patients when performed by experienced clinicians.

Comparing S-100 beta protein levels and neurocognitive functions between patients undergoing on-pump and off-pump coronary artery bypass grafting.

BACKGROUND: In the present study, we aimed to investigate the effects of off-pump coronary artery bypass grafting and on-pump cardiopulmonary bypass on the serum S-100 beta (S-100B) protein levels and neurocognitive functions of the patients. MATERIALS AND METHODS: Sixty-four patients undergoing coronary artery bypass grafting (CABG) were enrolled in the study and were divided into two groups: off-pump (group I, n = 24) and on-pump CABG (group II, n = 40) group. Serum S-100B levels were measured before and 0, 6, and 24 h after the operation. Neurocognitive function tests were done preoperatively and were repeated in the postoperative period as well. RESULTS: Serum S-100B levels were similar between the two groups preoperatively. However, median S-100B levels at 0, 6, and 24 h after the surgery were found to be significantly lower in the off-pump CABG group than in the on-pump group. The preoperative neurocognitive functions of the patients were similar between the two groups, whereas neurocognitive function was found to be significantly impaired postoperatively in the on-pump group in comparison with the off-pump CABG group. CONCLUSION: We concluded that off-pump CABG is associated with decreased serum S100 protein levels and less impairment on neurocognitive functions compared with the on-pump group.

Effects of angiogenesis inhibition by spironolactone on isolated vas deferens contractility in an experimental varicocele model in rats.

OBJECTIVE: To investigate the effect of spironolactone, as an angiogenesis inhibitor, on the isometric contractile responses in isolated vas deferens strips from left varicocele-induced rats. METHODS: Twenty-four adult (12-14 months) male Wistar albino rats were randomly assigned to 4 groups (n = 6 in each): (1) Control group, (2) sham-operated group, (3) experimental left varicocele group, and (4) Spironolactone (20 mg/kg/d)-treated experimental left varicocele group. Histopathologic and immunohistochemical (CD31 staining) findings in the rat testis and functional findings in the rat isolated vas deferens were investigated. RESULTS: Angiogenesis increased in the varicocele group and the spironolactone inhibited angiogenesis in the spironolactone-treated group. Spironolactone seemed to change phenylephrine and serotonin responses in the left vas deferens. CONCLUSION: It is possible that by inhibiting angiogenesis, spironolactone treatment negatively impairs testicular morphology and functional (vas deferens) pathways. Varicocele formation seems to elicit an increase to 5-HT sensitivity in rat vas deferens, and this process is prevented by spironolactone pretreatment.

Sequential radial artery for coronary artery bypass grafting: five-year follow-up and evaluation with multi-detector row computed tomography.

This study was undertaken to compare early postoperative results, programmed multi-detector row computed tomography coronary angiographic patency and midterm results of revascularization by sequential radial artery grafting with those of single radial artery grafting during a five-year period. Patients were grouped as those with sequential radial artery grafts (Group A, n = 27) and single radial artery grafts (Group B, n = 26). Multi-detector row computed tomography coronary angiography was scheduled at 1 and 5 years postoperatively. Each distal anastomosis was accepted as nonfunctional if a radial artery graft was occluded proximally or there was a critical stenosis. One sequential radial artery graft and two single radial artery grafts failed in the 1-year period (p>0.05). In the 5-year period, three radial artery grafts failed in each group (p>0.05). In Group A, there was no mortality in the five-year period, but in Group B, one patient died four years after the operation due to cardiac problems (p>0.05). In addition to one death in Group B, there were three percutaneous interventions and two myocardial infarctions among the 26 patients during the five-year follow-up. In group A, among 27 patients, there were 4 percutaneous interventions and one myocardial infarction (p>0.05). Although the sample size is relatively small to be conclusive, these data suggest that sequential radial artery grafting may be considered as a method of choice for maximizing arterial graft survival and patency. Noninvasive control of sequential and single radial artery grafts with multi-detector row computed tomography is feasible with no discomfort for the patient and excellent visualization of grafts.

Impact of a large hemodialysis arteriovenous fistula: on myocardial protection during cardiopulmonary bypass.

Arteriovenous fistulae have a substantial impact on systemic hemodynamics, but their effect on cardiopulmonary bypass is not well understood. The left-to-right shunting of blood through an arteriovenous fistula can create flow problems during cardiopulmonary bypass. We present the case of a 59-year-old man with end-stage renal disease who underwent coronary artery bypass grafting. During surgery, a large brachiocephalic arteriovenous fistula provided excessive venous return to the heart, compromising the myocardial protection offered by cardiopulmonary bypass. We modified the venous cannulation from a 2-stage single cannula to a bicaval cannula and were then able to achieve cardioplegic arrest and myocardial protection with no further problems.

Frequency of left atrial myxoma with concomitant coronary artery disease.

PURPOSE: Simultaneous coronary artery bypass grafting with a resection of left atrial myxoma has been rarely reported. The ages and the symptoms of patients who have left atrial myxomas and coronary artery disease are similar. In this report, we present our cases of left atrial myxoma with concomitant coronary artery disease who were all treated surgically. METHODS: Between September 1998 and January 2001, 11 patients were surgically treated after being diagnosed to have left atrial myxoma. Routine coronary angiography was performed on all patients preoperatively. In four patients concomitant coronary artery disease was identified. At surgery we performed coronary artery bypass grafting after a resection of left atrial myxoma in three patients. RESULTS: All patients were weaned from cardiopulmonary bypass without any difficulty. The postoperative course was uneventful. The follow-up period was 17 +/- 10 months (range 3-32 months). All patients were symptom-free and no recurrence of myxoma was detected. CONCLUSION: Based on our experience, cardiovascular surgeons should be aware of the concomitance of these diseases. It is therefore recommended that coronary angiography should be performed on all patients who present with left atrial myxomas.

Experience of the small size (25 mm) Sorin Bicarbon bileaflet prosthetic valve in patients with small mitral annuli.

BACKGROUND: Currently, there is a tendency to use large-size prosthetic valves in mitral position in order to achieve better hemodynamic performance. We aimed to evaluate hemodynamic performance of 25 mm prosthetic valves in mitral position. METHODS: Between August 1998 and May 2000, a total of 40 patients, 34 women and 6 men (mean age 42 +/- 12 years), underwent mitral valve replacement with 25 mm bileaflet mechanical valve. Preoperative functional capacity was New York Heart Association classes III and IV in 31 patients. Major indication for surgery was severe mitral stenosis in all patients. RESULTS: Total hospital mortality was 5% (two patients). Mean follow-up period was 14.7 +/- 4.9 months (2 to 23 months). No thromboembolic event, paravalvular leak, mechanical failure, endocarditis were observed during the follow-up period. Postoperatively 92.5% of the patients were in the functional capacity of New York Heart Association class I. Postoperative echocardiographic observations have given an average pulmonary artery pressure of 29 +/- 2 mmHg, effective orifice area as 2.95 +/- 0.1 cm2, and mean prosthetic gradient as 6.5 +/- 2.7 mmHg. CONCLUSION: In short- and mid-term, small-size (25 mm) Sorin mechanical mitral valves had excellent hemodynamic performance in patients with severe mitral stenosis, moderate or serious pulmonary hypertension, and small mitral annuli, whose body surface area was smaller than 1.6 m2.

Situs inversus and coronary artery disease.

Situs inversus is a rare condition and there are few reports of myocardial revascularization in such patients. A 56-year-old woman with situs inversus totalis and coronary artery disease underwent successful anastomosis of the right internal mammary artery to the anterior descending coronary artery, and a saphenous vein graft to the right coronary artery.

Cardiopulmonary bypass before general anesthesia in prosthetic valve thrombosis.

Valve obstruction is a lifethreatening complication of mechanical valve prostheses. Emergency operation is mandatory for patients who subsequently develop cardiogenic shock and severe pulmonary edema. In this severely compromised hemodynamic condition, cardiac arrest develops in most of the patients before surgery and just after general anesthesia induction. In one such case, we performed femorofemoral cardiopulmonary bypass with local anesthesia before general anesthesia induction and successfully replaced the thrombosed prosthetic valve, thus avoiding a catastrophic outcome.

Closed endarterectomy for diffuse right coronary artery disease: early results with angiographic controls.

BACKGROUND: Due to reported high morbidity and mortality, surgeons tend not to endarterectomize the diffusely diseased right coronary artery. Most prefer not to bypass this artery in such situation. We compared the endarterectomized right coronary patients with patients having total occlusion of right coronary artery not needing endarterectomy who received right coronary artery (RCA) bypass. MATERIAL AND METHODS: Between August 1998 and May 2000, 1226 patients had coronary artery bypass grafting (CABG) at Alkan Hospital, of whom 59 had right coronary artery endarterectomy (REC) along with RCA bypass with saphenous vein graft. We compared the results of 59 RCE patients with 50 patients who underwent RCA bypass without RCE. RESULTS: Compared with the control group, the RCE group had a higher incidence of diabetes. There were no statistically significant differences between groups for mortality and morbidity. Among postoperative variables only the cross-clamp time was longer for the RCE group (33.5 +/- 10 min vs. 27.3 +/- 8 min, p < 0.05). Surviving patients were followed for a mean period of 7 +/- 5 months. No recurrence of angina occurred during the follow-up. Control angiography at the sixth month was performed on 42 RCE patients accepting the procedure, and all grafts were found patent. CONCLUSION: Endarterectomy for diffusely atherosclerotic right coronary artery for selected patients did not bring additional mortality and morbidity to the CABG procedure, and short term clinical and angiographic results were excellent.