Electrovaporization of prostate at power settings below 100 W

BACKGROUND AND PURPOSE: Prostate electrovaporization has usually been performed at high power settings in the pure cut mode, using traditional electrosurgical generators. However, this practice is empirically based on the fact that a vaporization electrode is larger than a cutting wire loop. The role of the electrosurgical unit (ESU) in prostate electrovaporization has not been studied in detail. METHODS: In this Phase II cohort comparison study, we evaluated two different ESUs, coupled to the most clinically efficient vaporization roller electrode available in our opinion, to determine the lowest panel power settings that permit consistent tissue removal despite the desiccation normally produced during electrovaporization. RESULTS: One of these ESUs, the Excalibur Plus, permitted prostate electrovaporization at panel settings below 100 W for the first time, without compromising satisfactory early clinical outcomes. In a small number of cases, the spiked VaporTrode-Force 2 combination permitted effective electrovaporization at a lower power setting (180 W) than has previously been described when this ESU was coupled with the grooved VaporTrode, regardless of prostate size. During bench tests, a comparison of the actual power output curves in the clinically effective panel power setting range for each ESU revealed that the Force 2 overestimated the actual power output as impedance increased, while the Excalibur Plus underestimated it. This difference may explain why tissue could be vaporized at such low panel settings without the use of computer-controlled technology. CONCLUSION: These findings indicate a potential for improving the safety and efficiency of tissue clearance during prostate electrovaporization through future modifications in monopolar electrode design coupled with use of a generator that can either maintain or slowly increase actual power output as impedance increases at low panel settings. A Phase III clinical study would be justified on the basis of our preliminary results.     

Electrovaporization using a rollerball electrode for flat or small papillary tumors of the bladder: basic study in dogs.

PURPOSE: We investigated electrovaporization of flat bladder tumors with a rollerball electrode 3 mm in diameter as a substitute for conventional transurethral resection with a cutting loop. MATERIALS AND METHODS: A basic study of the action of electrovaporization was performed in dogs. The bladder was exposed under general anesthesia in three mongrel dogs. The rollerball electrode was attached to the resectoscope and inserted into the bladder via a cystostomy. Then electrovaporization was performed with a low or high pressure on the electrode tip and a speed of about 1 cm/sec using a Force 40 generator. The cutting mode power was set at 100 W or 200 W. The effects of the rollerball and cutting loop electrodes were also examined in the coagulation mode (45 W) as a control. RESULTS: A deeper vaporization zone was obtained by using a power of 200 W in the cutting mode than with a power of 100 W, and a desiccation zone was found below the vaporization zone (VZ). The VZ was thicker with a high contact pressure than with a low contact pressure. This VZ was deeper than the tissue defect and heat-affected zone obtained using a rollerball electrode or cutting loop electrode in the 45 W coagulation mode. CONCLUSION: Although caution is required because the VZ can become too deep with excessive pressure, the rollerball electrode seems to be safer and more useful than the cutting loop electrode for resection of flat or small papillary bladder tumors.     

Radiofrequency energy antenna coupling to common laparoscopic instruments: practical implications

Background

Electromagnetic coupling can occur between the monopolar “Bovie” instrument and other laparoscopic instruments without direct contact by a phenomenon termed antenna coupling. The purpose of this study was to determine if, and to what extent, radiofrequency energy couples to other common laparoscopic instruments and to describe practical steps that can minimize the magnitude of antenna coupling.

Methods

In a laparoscopic simulator, monopolar radiofrequency energy was delivered to an L-hook. The tips of standard, nonelectrical laparoscopic instruments (either an unlit 10?mm telescope or a 5?mm grasper) were placed adjacent to bovine liver tissue and were never in contact with the active electrode. Thermal imaging quantified the change in tissue temperature nearest the tip of the telescope or grasper at the end of a 5?s activation of the active electrode.

Results

A 5?s activation (30 watts, coagulation mode, 4?cm separation between instruments) increased tissue temperature compared with baseline adjacent to the grasper tip (2.2?±?2.2?°C; p?=?0.013) and telescope tip (38.2?±?8.0?°C; p?<?0.001). The laparoscopic telescope tip increased tissue temperature more than the laparoscopic grasper tip (p?<?0.001). Lowering the generator power from 30 to 15 Watts decreased the heat generated at the telescope tip (38.2?±?8.0 vs. 13.5?±?7.5?°C; p?<?0.001). Complete separation of the camera/light cords and the active electrode cord decreased the heat generated near the telescope tip compared with parallel bundling of the cords (38.2?±?8.0 vs. 15.7?±?11.6?°C; p?<?0.001).

Conclusions

Commonly used laparoscopic instruments couple monopolar radiofrequency energy without direct contact with the active electrode, a phenomenon that results in heat transfer from a nonelectrically active instrument tip to adjacent tissue. Practical steps to minimize heat transfer resulting from antenna coupling include reducing the monopolar generator power setting and avoiding of parallel bundling of the telescope and active electrode cords.     

Increased staple loading pressures and reduced staple heights in laparoscopic sleeve gastrectomy reduce intraoperative bleeding

BackgroundIn laparoscopic sleeve gastrectomy, tissue thickness and closed staple height of the staple cartridge determine the pressure applied to the tissue. Prior studies have suggested 8 g/mm² to be ideal to minimize leaks or bleeding.MethodsWe evaluated the relationship between staple loading pressure applied to gastric tissue and bleeding rate prospectively with a novel tissue measuring device and video-recorded operative findings for 116 patients undergoing laparoscopic sleeve gastrectomy performed by 2 surgeons at a single institution. Stapling protocol 1 was used for 64 cases, defined as standard practice, typically using green-blue-blue-blue Ethicon staple cartridges. Stapling protocol 2 was defined as blue-blue-white-white or gold-blue-white-white.ResultsTissue thickness measurements from 39 cases and staple load selection showed that surgeons preferred a median staple loading pressure of 15 g/mm². Tissue thickness measurements at 15 g/mm² had a mean of 1.86 mm at the antrum, 1.71 mm at the body, and 1.15 mm at the fundus, all significantly thinner than tissue thickness at 8 g/mm². For each 10 g/mm² increase in minimum pressure and maximum pressure value within each cartridge zone, there was a reduction in bleeding rate by 59.8% and 38.7%, respectively. Compared with stapling protocol 1, stapling protocol 2 had a lower intraoperative bleeding rate (90.2% vs 70.7%; P < .0001), usage of preventive hemostatic techniques (100% vs 10%; P < .0001), and hemostatic treatments (66% vs 46%; P = .04). In the 30-day postoperative period, there was 1 bleed in stapling protocol 1; there were no leaks.ConclusionOur data suggest using shorter closed staple heights to exert higher staple loading pressures decreases intraoperative bleeding rates in laparoscopic sleeve gastrectomy.     

Primary Cutaneous Melanoma with Regression Does not Require a Lower Threshold for Sentinel Lymph Node Biopsy

Introduction Histological evidence of primary tumor regression (RG) is observed in 35% or fewer patients with cutaneous melanoma. Some advocate a lower threshold for sentinel lymph node (SLN) biopsy when RG is present. Methods We identified 1,349 patients presenting to our center with clinically localized cutaneous melanoma between 1995 and 2004. Of these, 344 demonstrated histological RG in their primary melanoma. A retrospective analysis of their medical records was performed to obtain clinical and pathological information. Results The median Breslow depth for the 344 patients with RG was 1.1 mm versus 1.5 mm for 1,005 patients with no regression (NRG) (P < 0.005). SLN biopsy was performed in 64% of patients with RG and 72% without. Positive SLN was more common in those with NRG than in those with RG (18% vs 10%, P = 0.005). Only one RG patient with thin melanoma (≤1 mm, Clark IV) had a positive SLN. When stratified by Breslow depth, patients with RG had lower rates of SLN positivity in all groups (≤1.0mm, >1.0 and ≤2.0mm, >2 and ≤4 mm, and >4.0 mm). Recurrence was more common in patients with NRG (21% vs 12%; P < 0.005). Both local and systemic recurrence occurred more commonly in patients with NRG (4% vs 1%, P = 0.002 and 8% vs 3%, P < 0.005, respectively) Conclusions The presence of histological RG in a primary melanoma predicts neither SLN positivity when stratified by Breslow depth nor increased risk of recurrence when compared with melanomas with NRG.     

Ex vivo and in vivo investigations of the novel 1,470 nm diode laser for potential treatment of benign prostatic enlargement

Perioperative haemorrhage is still the major complication of transurethral resection of the prostate (TURP) for benign enlargement of the prostate. Photoselective vaporisation of the prostate (PVP) with the potassium–titanyl–phosphate (KTP) laser has been shown to achieve instant tissue ablation with excellent haemostatic properties. Our aim was to determine the tissue removal capacity, coagulation and haemostatic property of the novel 1,470 nm diode laser, ex vivo and in vivo. We evaluated two prototype diode laser systems at 1,470 nm in an ex vivo, isolated, blood-perfused, porcine kidney model (n = 5; 10 W–50 W) and in an in vivo investigation of beagle prostate (n = 4; 100 W) to assess vaporisation capacities and coagulation properties at different generator settings. The diode laser evaluation was compared with an 80 W KTP laser in the porcine model. After the laser treatment we performed a histological examination to compare the depth of coagulation and vaporisation. The diode laser system (50 W) showed significantly lower (P < 0.0001) capacities for tissue removal than the 80 W KTP laser (0.96 mm ± 0.17 mm and 5.93 mm ± 0.25 mm, respectively, P < 0.0001), while coagulation zones were significantly (P < 0.001) larger in diode laser-treated kidneys (3,39 mm ± 0.93 mm and 1.27 mm ± 0.13 mm, respectively). In vivo, the diode laser displayed rapid ablation of prostatic tissue with no intraoperative haemorrhage. Histological examination revealed coagulation zones of 2.30 mm (±0.26) at 100 W in the diode laser-treated prostates.     

Effect of steroids or tissue preceding on edema and tissue thermal coagulation after CO2 laser impact

The carbon dioxide laser is frequently used in laryngeal microsurgery. Some surgeons have empirically used preoperative steroids or precooling with ice prior to laser impact to limit the resultant tissue thermal coagulation and/or edema. An animal model was designed to quantitatively test these effects. Depillated areas of rat skin were exposed to a CO₂ beam of 1 mm diameter at 15 W for 0.1 sec after either administration of Decadron (0.25 mg/kg) immediately prior to impact or precooling more than 10^oC below basal body temperature. Measurement of edema was quantitated as extravasation of Evan's blue dye that had been injected intravenously. Tissue thermal coagulation was measured on hematoxylin and eosin stained histologic sections. In comparison to controls, statistically significant reduction in edema was seen only at the 24 hour time period after laser exposure for the steroid group (P<.002) but not for the precooling group. Tissue thermal coagulation was significantly smaller for both the steroid and the ice group (P < .006 and P < .001, respectively) when compared to controls. © 1992 Wiley-Liss, Inc.     

Preliminary evaluation of a novel side-fire diode laser emitting light at 940 nm, for the potential treatment of benign prostatic hyperplasia: ex-vivo and in-vivo investigations

OBJECTIVES

To evaluate, ex vivo and in vivo, the tissue‐removal capacity and coagulation properties of a diode laser emitting light at 940 nm, as in the search for potential therapeutic strategies for benign prostatic hyperplasia that cause less morbidity than transurethral resection of the prostate (TURP), various types of lasers have been tested.

MATERIALS AND METHODS

A diode laser system (prototype; wavelength 940 nm, Dornier MedTech, Wessling, Germany) was evaluated in an isolated, blood‐perfused ex‐vivo porcine kidney model at 10–60 W (five kidneys). An in‐vivo beagle model was used to investigate the effects on six prostate lobes at a generator output power level of 200 W. After the laser treatment tissue were examined histologically to compare the depth of coagulation and vaporization.

RESULTS

With increasing generator output power levels there was an increasing vaporization and coagulation ability for the diode laser at 940 nm in the ex‐vivo model. At 60 W the mean (sd ) vaporization depth was 1.72 (0.47) mm with a coagulation zone of 9.56 (0.26) mm. In vivo, the diode laser caused rapid ablation with no intraoperative haemorrhage. Histologically, the zone of coagulation had a mean (sd ) depth of 4.25 (0.15) mm at 200 W. The tissue removal capacity was estimated at 0.874–1.583 g/min in vivo.

CONCLUSIONS

Our findings indicate that diode‐laser vaporization at 940 nm is feasible and might be effective for acutely relieving bladder outlet obstruction in an in‐vivo setting. Due to its mean coagulation zone of 4.25 mm the diode laser seems to have effective haemostatic properties.     

Right Ventricle Dysfunction in Patients With Adult Cystic Fibrosis Enlisted for Lung Transplant

Knowledge of preoperative right heart function of adult patients with cystic fibrosis (CF) awaiting lung transplant (LUTX) is limited. The echocardiography of adult patients with CF enlisted for LUTX was retrospectively analyzed and compared with standards and invasive analyses (right heart catheterization, multigated radionuclide ventriculography). We included 49 patients (reported as mean ± standard deviation; 29 ± 9 years of age; forced expiratory volume in first second of expiration, 31% ± 11% predicted; lung allocation score, 36 ± 5; invasive mean pulmonary artery pressure, 17 ± 5 mm Hg; multigated radionuclide ventriculography right ventricle [RV] ejection fraction, 50% ± 9%). Patients had increased RV end-diastolic area, RV wall thickness, and increased pulmonary artery acceleration time with subnormal tricuspid annular plane systolic excursion, tissue Doppler positive peak systolic velocity, and fraction area change. Subnormal tricuspid annular plane systolic excursion (< 23 mm), tissue Doppler positive peak systolic velocity (< 14 cm/s), and fraction area change (< 49%) had high sensitivity and negative predictive value in predicting impaired RV.ejection fractionA good correlation between echocardiographic estimated and invasively measured systolic pulmonary artery pressure was observed (R² = 0.554, P < .001). Adults with CF awaiting LUTX have morphologic alterations of the right heart, with subclinical impairment of RV systolic function. Echocardiography may be used as a bedside, repeatable, and reliable noninvasive test to screen further deterioration in RV function while on the waiting list for LUTX. More prospective follow-up echocardiographic studies are necessary to confirm such a hypothesis.     

Skin Involvement in Invasive Breast Carcinoma: Safety of Skin-Sparing Mastectomy

Background:There is concern about the oncological safety of preserving most of the breast skin in skin-sparing mastectomy (SSM). Most supportive evidence for SSM evaluates the local recurrence rate on clinical follow-up.Methods:The skin and 10 mm of the subcutaneous tissue of 30 total mastectomy specimens were studied with a step-serial sectioning technique. The incidence and mode of involvement of the skin and subcutaneous tissue were recorded in detail. This was correlated with other clinical and pathologic parameters.Results:The incidence of skin involvement outside the nipple-areola complex was 20% (6 of 30). This was significantly related to the clinical T stage, site of the tumor, skin tethering, pathologic tumor size, and perineural infiltration. When the effects of both skin and subcutaneous tissue involvement were considered, the incidence of skin-flap involvement outside the nipple-areola complex was 23% (7 of 30). The significant parameters related to skin-flap involvement were skin tethering (75% vs. 15%; P < .05), pathologic tumor size (P < .03), and perineural infiltration (63% vs. 9%; P < .01).Conclusions:It would be oncologically safe to perform SSM in T1 and T2 tumors, because the chance of skin involvement is small. It is safe to preserve the skin overlying the tumor if there is no skin tethering.     

False negative mammography: causes and consequences

A retrospective review was undertaken of 174 women presenting consecutively to a symptomatic clinic and subsequently found to have breast cancer. Their mammograms, clinical and pathological findings were reviewed. Any delay occurring between presentation and treatment was recorded. Mammography showed a sensitivity of 83.3% overall (95% confidence interval 77.0–88.5). Negative mammogram reports were associated with age under 50 (P = 0.01−0.005), premenopausal status (P = 0.01−0.005), dense breast parenchyma (P = 0.005−0.001), in situ disease (P = 0.0078), small tumour size < 20 mm (P = 0.0173) and negative cytology (P = 0.0173). A negative mammogram resulted in a delay to definitive treatment. Median time to treatment for negative versus positive mammography was 7 weeks (range 1–90) versus 3 weeks (range 0–18) P = < 0.001, mean times being 13.4 weeks and 3.5 weeks. There was clinical progression in over half of the women whose treatment was delayed (P = 0.006). When clinical or cytological suspicion remains following triple assessment, negative mammography should not delay definitive histological diagnosis.     

Comparative experimental study of argon plasma and bipolar coagulation techniques

Summary Background. Argon plasma coagulation (APC) is based on the principle of ionised argon creating conductive plasma between an activating electrode and tissue surface and is used as an effective alternative coagulation technique in various surgical disciplines. This trial aims to compare thermal injury in rat brain caused by APC and conventional bipolar coagulation technique. Methods. A controlled study design with constant power setting and application time was established. Twenty rats were randomised into the APC and bipolar groups. Each group of ten rats had 20 treated lesions. Early and late histopathological changes, as well as maximum extent of the lesion after 48 hours (h) and 12 days were studied in overall 20 lesions. Findings. Although the maximum depth of the lesions was different in APC (2.2 mm) and bipolar (1.8 mm) groups after 48 h, this did not achieve statistical significance (p = 0.151). The superficially coagulated area was significantly larger after APC compared with the bipolar technique at the 48 h time point (p = 0.032). After twelve days there were no differences in penetration depth (p = 0.310) or coagulated area (p = 0.222). Conclusion. Tissue defects after APC application on rat brains were comparable to conventional bipolar technique in this trial. The results suggest that argon plasma coagulation (APC) is an effective coagulation technique.     

Cell Cycle Proteins Predict Recurrence in Stage II and III Colon Cancer

Purpose

To investigate the prognostic value of multiple cell cycle-associated proteins in a large series of stage II and III colon cancers.

Methods

From formalin-fixed, paraffin-embedded tumor samples of 386 patients with stage II and III colon cancer, DNA was isolated and tissue microarrays were constructed. Tissue microarray slides were immunohistochemically stained for p21, p27, p53, epidermal growth factor receptor, Her2/Neu, β-catenin, cyclin D1, Ki-67, thymidylate synthase, and Aurora kinase A (AURKA). Polymerase chain reaction–based microsatellite instability analysis was performed to allow for stratification of protein expression by microsatellite instability status.

Results

Overall, low p21, high p53, low cyclin D1, and high AURKA expression were significantly associated with recurrence (P = 0.01, P < 0.01, P = 0.04, and P < 0.01, respectively). In stage II patients who did not receive adjuvant chemotherapy (n = 190), significantly more recurrences were observed in case of low-p21 and high-p53-expressing tumors (P < 0.01 and P = 0.03, respectively). In stage III patients who did not receive chemotherapy, high p53 expression was associated with recurrence (P = 0.02), and in patients who received chemotherapy, high AURKA expression was associated with relapse (P < 0.01). In patients with microsatellite stable tumors, high levels of p53 and AURKA were associated with recurrence (P = 0.01 and P < 0.01, respectively). Multivariate analysis showed p21 (odds ratio 1.6, 95% confidence interval 0.9–2.8) and AURKA (odds ratio 2.7, 95% confidence interval 1.3–5.6) to be independently associated with disease recurrence.

Conclusions

p21, p53, cyclin D1, and AURKA could possibly be used as prognostic markers to identify colon cancer patients with high risk of disease recurrence.

     

Ultrasound assessment of extensor pollicis brevis tendon excursion in different wrist positions in healthy people

Study DesignCross-sectional, observational study.IntroductionThere is little reported on the in vivo mechanics and behavior of extensor pollicis brevis (EPB) in relation to wrist position. Wrist position is known to significantly influence tendon excursion and therefore function of the digits. Ultrasound imaging (USI) can be used to assess in vivo tendon behavior and excursion. An improved knowledge of the excursion of the EPB tendon is important in understanding normal tendon mechanics and potentially pathological tendon disorders such as de Quervains tenosynovitis.Purpose of the StudyTo assess the reliability of using USI to measure EPB tendon excursion and to quantify EPB tendon excursion in 3 wrist positions.MethodsUSI with speckle-tracking analysis were utilized to assess 49 normal EPB tendons (25 subjects). Tendon excursion was measured in wrist flexion (45°), wrist neutral and wrist extension (45°) on 2 different occasions.ResultsThe within- and between-session reliability of using USI to quantify EPB tendon excursion was “excellent” and “high,” respectively. Wrist position had a significant influence on EPB tendon excursion (P ≤ .05). EPB excursion in the neutral wrist position was statistically greater than the other 2 positions (P < .05).DiscussionEPB tendon excursion has been shown to be dependent on the wrist positions of flexion and extension. The measures are notably lower than those found in cadaver studies; however, they follow a similar pattern with greatest excursion occurring in the neutral wrist position and least in flexion. This information is useful for EPB tendon rehabilitation and in consideration of biomechanics and pathogenesis of disorders that affect EPB tendon.ConclusionIn vivo EPB tendon excursion measures have been quantified, and wrist position has been found to have an influence on excursion. USI with speckle-tracking analysis are considered to be reliable methods for measuring EPB tendon excursion.     

Overexpression of Sox3 is Associated with Diminished Prognosis in Esophageal Squamous Cell Carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is a lethal malignancy lacking valid prognostic biomarkers. As a member of the High Mobility Group domain-containing DNA-binding proteins, Sox3 has been reported to induce oncogenic transformation of chicken embryo fibroblasts. However, the expression and prognostic value of Sox3 in ESCC remain unclear.

Methods

A total of 30 pairs of ESCC with a corresponding non-neoplastic esophageal epithelium (NE) specimen were investigated for Sox3 expression using RT-PCR and western blot analysis. Tissue microarrays containing 118 ESCC and 30 NE samples were detected for Sox3 expression using immunohistochemical staining. The relationship of Sox3 staining with various clinicopathological characteristics and survival of patients was statistically analyzed.

Results

Sox3 expression in ESCC was 3.1- and 2.7-fold higher than in NE at mRNA (P < 0.001) and protein level (P < 0.001), respectively. Positive staining of Sox3 was observed in 77.1 % of the ESCC and 16.7 % of the NE samples (P < 0.001). High expression of Sox3 was significantly correlated with the regional lymph nodes metastasis (RLNM) (P = 0.022) and advanced TNM stage (P = 0.011). Moreover, high expression of Sox3 was significantly associated with poor overall survival (P < 0.001) and recurrence-free survival (P < 0.001) in ESCC patients. Both Sox3 expression (P < 0.001) and RLNM (P = 0.002) were independent prognostic factors for patients with ESCC.

Conclusions

Sox3 might play a positive role in tumor development and could serve as an independent predictor of poor prognosis for ESCC.

     

Specific foraminal changes originate from degenerative spondylolisthesis on computed tomographic images

Purpose

Operative treatment for degenerative spondylolisthesis (DS) is accompanied by the high incidence of nerve injury. Foraminal structures, especially the hypertrophied facet joints, have significant impacts on the adjacent nerve. This study aims to identify the specific foraminal changes relating to DS and nerve injury.

Methods

The CT images of 70 patients with DS and 50 patients without lumbar disease were collected. The length and height of the foraminal structure were measured horizontally and vertically on sagittally reconstructed images. Horizontal stenosis, meaning to pending compression to nerve root after complete reduction, was evaluated on the image located to the middle of the foramen. Chi-square test or T-test were carried out using SPSS 26.0.

Results

The hyperplasia of the superior articular process (SAP) and articular capsule (Ac) incidence rates in DS group was significantly more common than that of the control group (9.2 vs 0.0%, 42.9 vs 2.0%). The height and width of the SAP and Ac in vertical and horizontal directions were significantly greater than those in the control group (4.95 mm vs − 0.47 mm, P < 0.0001; 3.28 vs 0.02 mm, P < 0.0001; 5.27 vs3.44 mm, P < 0.0001; 2.60 vs 0.37 mm, P < 0.0001). In the DS group, hyperplasia of the SAP and Ac accounted for 9 and 43% respectively, 85 and 45% of which were accompanied by horizontal stenosis of the intervertebral foramen.

Conclusion

DS is usually characterized of excessive hyperplasia of the SAP and Ac, both of which are possible elements of nerve root injury after complete reduction in operation and should be focused on during surgery.

     

Echocardiographic Changes in the Context of Metal-on-Metal Versus Nonmetal-on-Metal Total Hip Arthroplasty

BackgroundThe purpose of this study is to determine if there is a difference in echocardiographic results between patients with metal-on-metal (MoM) vs non-MoM total hip arthroplasty (THA) and to determine if a correlation exists between serum metal levels and echocardiographic outcomes.MethodsSeventy-five patients with the same modular THA enrolled in this prospective cohort study, and 49 had MoM bearings. All patients had serum cobalt, chromium, and titanium levels drawn at 2 study visits with a transthoracic echocardiogram at the second visit. Serum metal concentrations and echocardiographic parameters were compared with 2-way t-tests. Multiple linear regression analyses identified any significant predictors of echocardiographic outcomes.ResultsMean serum cobalt and chromium levels were significantly greater in the MoM group at both time-points (P < .001 and P < .05, respectively). Titanium levels were similar between groups (P > .05). MoM patients had significantly lower global longitudinal strain compared with the non-MoM group (18.4% vs 20.2%; P = .026). Serum cobalt concentration was found to be an independent predictor of tricuspid annular plane systolic excursion (P = .02).ConclusionMoM THA bearings are associated with increased serum cobalt and chromium levels. Patients with MoM THAs had decreased global longitudinal strain, a measure of left ventricular function, but both groups remained within normal range. The clinical impact of the positive association between serum cobalt concentration and tricuspid annular plane systolic excursion, a marker of right ventricular function, deserves further study. These findings can reassure physicians and patients that metal-induced cardiomyopathy is not typical in the setting of MoM THA.Level of EvidenceLevel II, Prospective Cohort Study.     

Altered Plasma Antigen Levels of Tissue Factor Pathway Inhibitor During Open-Heart Surgery

r = 0.96, P < 0.0001) which increased significantly after heparin injection (P < 0.0001), and increased further during the bypass period (P < 0.005). The increased free TFPI antigen level during CPB correlated with the duration of bypass (r = 0.65, P = 0.02). When heparin was neutralized by protamine, the free TFPI antigen level decreased immediately, but remained higher than the preoperative level (P < 0.005). These results suggest that plasma TFPI antigen levels increase during CPB. (Received for publication on Dec. 14, 1998; accepted on July 13, 1999)     

Anesthesia care for subcutaneous implantable cardioverter/defibrillator placement: a single-center experience

BackgroundThe recently approved subcutaneous implantable cardioverter/defibrillator (S-ICD) uses a single extrathoracic subcutaneous lead to treat life-threatening ventricular arrhythmias, such as ventricular tachycardia and ventricular fibrillation. This is different from conventional transvenous ICDs, which are typically implanted under sedation. Currently, there are no reports regarding the anesthetic management of patients undergoing S-ICD implantation.Study objectivesThis study describes the anesthetic management and outcomes in patients undergoing S-ICD implantation and defibrillation threshold (DFT) testing.MethodsThe study population consists of 73 patients who underwent S-ICD implantation. General anesthesia (n = 69, 95%) or conscious/deep sedation (n = 4, 5%) was used for device implantation.MeasurementsSystolic blood pressure (SBP) and heart rate were recorded periprocedurally for S-ICD implantation and DFTs. Major adverse events were SBP < 90 mm Hg refractory to vasopressor agents, significant bradycardia (heart rate < 45 beats per minute) requiring pharmacologic intervention and, “severe” pain at the lead tunneling site and the S-ICD generator insertion site based on patient perception.InterventionsOf the 73 patients, 39 had SBP < 90 mm Hg (53%), and intermittent boluses of vasopressors and inotropes were administered with recovery of SBP. In 2 patients, SBP did not respond, and the patients required vasopressor infusion in the intensive care unit.Main resultsAlthough the S-ICD procedure involved extensive tunneling and a mean of 2.5 ± 1.7 DFTs per patient, refractory hypotension was a major adverse event in only 2 patients. The mean baseline SBP was 132.5 ± 22.0 mm Hg, and the mean minimum SBP during the procedure was 97.3 ± 9.2 mm Hg (P < .01). There was also a mean 13–beats per minute decrease in heart rate (P < .01), but no pharmacologic intervention was required. Eight patients developed “severe” pain at the lead tunneling and generator insertion sites and were adequately managed with intravenous morphine.ConclusionsAmong a heterogeneous population, anesthesiologists can safely manage patients undergoing S-ICD implantation and repeated DFTs without wide swings in SBP and with minimal intermittent pharmacologic support.     

Effect of Lead on Bone Development and Bone Mass: A Morphometric,Densitometric, and Histomorphometric Study in Growing Rats

The effect of exposure to lead on the longitudinal development of bone and on bone mass was studied in rats. A group of 35, 50-day-old female Wistar rats was divided into a control group of 15 rats and an experimental group of 20 rats fed a diet supplemented with 17 mg of lead acetate per kg feed for 50 days. Total body bone densitometry (TBBMC) was performed the day before ending the 50-day experiment. On day 50, all rats were killed and their right femur and 5th lumbar vertebra were dissected. The bones were cleaned of soft tissue and femoral length and vertebral length were measured with a caliper and all bones were weighed on a precision scale. Final body weight (P < 0.05), TBBMC (P < 0.005), and femur weight (P < 0.005) were significantly lower in the control group. Femur length did not differ between groups, but the length of the 5th lumbar vertebra was greater in the control group (P < 0.05). Histomorphometry of the femur showed that Cn-BV/TV, Tb-N, Tb-Th were lower (P < 0.05 in all) and Tb-Sp was higher (P < 0.05) in the group given the lead-supplemented diet. These findings suggested lead-induced inhibition of axial bone development and a histomorphometric decrease in bone mass, produced mainly by enhanced resorption, and a densitometric increase in bone mass, produced by lead accumulation in bone. Received: 12 February 1996 / Accepted: 15 July 1996