Fracture resistance of teeth restored with endocrowns: An in vitro study.

OBJECTIVE: The objective of this study is to evaluate the fracture resistance and failure mode of endodontically treated teeth restored with lithium disilicate endocrowns of different crown thicknesses. MATERIALS AND METHODS: A total of 30 endodontically treated permanent mandibular first molars were sectioned horizontally 2 mm above the highest point of the cemento-enamel junction. The specimens were divided into three groups, and each group was restored with lithium disilicate (IPS e-max press) endocrowns of different crown thicknesses (3, 4.5, and 6 mm, respectively). After cementation, specimens were stored in room temperature for 72 hours, followed by subjecting them to compressive strength testing until failure. The fracture loads and the failure mode were recorded. Statistically analysis was performed using one-way analysis of variance. RESULTS: A statistically significant difference was found in the fracture resistance between the three groups with the highest fracture resistance in the 3 mm group, followed by the 4.5 mm group, and the least in the 6 mm group (P < .05). Most of the failures were accompanied with tooth fracture (90% in 3 mm group, 100% in 4.5 mm group, and 80% in 6 mm group). CONCLUSIONS: Increasing the crown thickness of the endocrowns reduced the fracture resistance of restored teeth. Minimum fracture loads for all teeth restored with endocrowns were significantly higher than the maximum occlusal forces reported in the literature. CLINICAL SIGNIFICANCE: Fracture resistance and mode of failure of lithium disilicate (IPS e-max press) endocrowns varies widely between crown thicknesses. Clinicians should be cautious with crown thickness for endocrown restorations.

Shaping Ability of HyFlex EDM and ProTaper Next Rotary Instruments in Curved Root Canals: A Micro-CT Study.

AIM: The aim of this study is to evaluate and compare the shaping ability of HyFlex™ EDM (HFEDM) and ProTaper Next (PTN) rotary instruments in curved root canals by using micro-computed tomography (micro-CT) imaging. MATERIALS AND METHODS: A total of 22 mandibular molar teeth having separate mesial canals with 20 to 30° curvatures were randomly divided into two groups and instrumented with HFEDM (OneFile) or PTN (X1 and X2). Pre- and post-instrumentation micro-CT scans were obtained. Mesiodistal canal transportation and centering ability were evaluated in four cross-sections (2, 4, 6, and 8 mm from apex). Changes in canal volume and surface area were measured for a 10-mm standardized area of interest. Kolmogorov-Smirnov and Shapiro-Wilk tests were used to assess the normality and homogeneity. Independent and paired t tests and one-way ANOVA were used to analyze data at the p < 0.05 level. RESULTS: Compared to PTN, HFEDM showed significantly less mesiodistal canal transportation and improved centering ability in cross-section L6 (p < 0.05). The instruments showed similar increases in volume and surface area of the canals, with minor insignificant differences. CONCLUSION: HFEDM and PTN files were safe to use in curved canals and showed similar shaping ability, while respecting the original anatomies. HFEDM OneFile performed better at the vicinity of the danger zone in terms of mesiodistal canal transportation and centering ability.

Anesthesia for thoracic surgery: a survey of middle eastern practice.

PURPOSE: The main objective of this survey is to describe the current practice of thoracic anesthesia in the Middle Eastern (ME) region. METHODS: A prospective online survey. An invitation to participate was e-mailed to all members of the ME thoracic-anaesthesia group. A total of 58 members participated in the survey from 19 institutions in the Middle East. Questions concerned ventilation strategies during one-lung ventilation (OLV), anesthesia regimen, mode of postoperative analgesia, use of lung isolation techniques, and use of i.v. fluids. RESULTS: Volume-controlled ventilation was favored over pressure-controlled ventilation (62% vs 38% of respondents, P<0.05); 43% report the routine use of positive end-expiratory pressure. One hundred percent of respondents report using double-lumen tube (DLT) as a first choice airway to establish OLV. Nearly a third of respondents, 31.1%, report never using bronchial blocker (BB) in their thoracic anesthesia practice. Failure to pass a DLT and difficult airway are the most commonly cited indications for BB use. Regarding postoperative analgesia, the majority 61.8% favor thoracic epidural analgesia over other techniques (P<0.05). CONCLUSIONS: Our survey provides a contemporary snapshot of the ME thoracic anesthetic practice.

Laryngeal mask airway vs. uncuffed endotracheal tube for nasal and paranasal sinus surgery: paediatric airway protection.

BACKGROUND AND OBJECTIVE: Risks are anticipated for laryngeal mask airway (LMA) anaesthesia during nasal and sinus surgeries because blood can trickle posteriorly into the hypopharynx and contaminate the airway. This study was conducted to determine whether a LMA could provide adequate airway protection from the expected intraoperative bleeding. METHODS: After obtaining ethics committee approval, 60 children ASA status I or II, 1-12 years of age, and scheduled for nasal and sinus surgery were randomized to one of two groups, endotracheal tube (ETT) or LMA, with 30 patients in each. Topical lidocaine with adrenaline was used in all patients, and throat packs were used for the ETT group. The airway was examined using a fibreoptic endoscope in order to determine whether blood or tissue debris soiled the supraglottic airway or trachea. After extubation, LMAs and ETTs were examined for soiling by blood and graded on a scale of 0-3. For ETT, the grades were 0, none; 1, contamination above the mark for vocal cord depth; 2, contamination below the mark for vocal cord depth; and 3, contamination interiorly. For LMA, they were 0, no staining; 1, staining on the anterior aspect of the cuff of the LMA; 2, staining inside the cup of the LMA; and 3, staining found in the tube. RESULTS: Blood stains were found in the larynx of one child in the LMA group. In the ETT group, there were three cases of staining (two supraglottic and one in the trachea, P = 0.161). With the LMA, 12 (40%) and 18 (60%) patients had visual contamination scores of 0 and 1, respectively. With the ETT, 14 (46.7%), 10 (33.3%), and six (20%) patients had visual contamination scores of 0, 1, and 2, respectively (P = 0.0123). CONCLUSION: LMA is a suitable method for paediatric patients undergoing sinonasal surgery because it offers airway protection from blood contamination comparable to that of a standard uncuffed ETT with throat pack.

Comparison of the outer diameter of the 'best-fit' endotracheal tube with MRI-measured airway diameter at the cricoid level.

BACKGROUND AND OBJECTIVE: In this study, we evaluated the ratio of the outer diameter of an uncuffed Mallinckrodt endotracheal tube (ETT, Mallinckrodt Tyco Healthcare UK Ltd) to the MRI-measured internal transverse airway diameter (ITD) at the cricoid level in children. METHODS: With institutional ethics committee approval and parental consent, we measured the ITD at the cricoid level from MRI images of children undergoing MRI diagnostic procedures requiring general anaesthesia with orotracheal intubation. The ITD at the cricoid level was compared with the outer diameter of the utilized ETT. Linear regression analysis was employed to assess the correlation of tracheal diameter with age, height and weight. For all tests, a P value of less than 0.05 was considered to be statistically significant. RESULTS: Fifty patients were studied (21 girls and 29 boys). The difference between the ITD at the cricoid level and the outer tracheal tube diameter ranged from 0.1 to 1.7 mm (median 0.7 mm). The internal transverse tracheal diameters had a strong association with age (r=0.7077, P<0.001), a moderate association with height (r=0.5928, P<0.001), and a mild association with weight (r=0.2437, P<0.001). CONCLUSION: The outer diameter of the 'best-fit' ETT was less than the ITD at the cricoid level by 0.1-1.7 mm. The correlation of the outer diameter of the 'best-fit' ETT with age was stronger than with height or weight.

Critical incident monitoring in a teaching hospital--the third report 2003-2008.

UNLABELLED: Several factors have been incriminated in the etiologies of critical incidents: shortages in organizing rules, anesthesia technique, patient environment, human factor, team work and communication. This is the third follow up report describing our performance during the last five years (2003-2008). The possible incriminating causes were identified with the objective of avoiding such eventualities and consequently providing a better patient outcome. PATIENTS & METHODS: The computerized database and the medical records of critical incidents reports in our Department during the period of 2003-2008 were reviewed on case-by-case basis. Seventy reported incidents were discussed in the Department's Morbidity & Mortality Meetings (MMM). Incidents were classified as per possible incriminating causes: pulmonary, cardiovascular, central nervous system, metabolic, inadvertent drug injection, communicating failure, equipment failure and miscellaneous causes. RESULTS: Most of the critical incidents reports occurred during maintenance of anesthesia, followed next by during induction and next by same operative day later in the ward. The majority of cases were respiratory events (29 cases), followed by communication failure (12 cases), failure of equipment (9 cases) and inadvertent drug injection (4 cases). CONCLUSIONS: Respiratory events, human errors, team communication and equipment failures, continue to be the leading causes of critical incidents. Critical incidents are apt to occur so long as the human factor is involved. Vigilance in operational efficiency and the scrutiny in drug administration, supervision and training should be closely monitored in order to minimize critical incident reports.

Effect of fluid preloading on postoperative nausea and vomiting following laparoscopic cholecystectomy.

BACKGROUND: Postoperative nausea and vomiting (PONV) is a common complication following general anesthesia. Different regimens have been described for the treatment of PONV with few that mention the prevention of it. Therefore, we conducted this study to compare the effect of preloading with either crystalloids or colloids on the incidence of PONV following laparoscopic cholecystectomy (LC), under general anesthesia. MATERIALS AND METHODS: This study was carried out on 80 patients who underwent LC. The patients were divided into four groups (each 20 patients), to receive preloading of intravenous fluid, as follows: Group 1 received, 10 ml/kg of low-MW tetrastarch in saline (Voluven), group 2 received, 10 ml/kg medium-MW pentastarch in saline (Pentaspan), group 3, received 10 ml/kg of high-MW heta-starch in saline (Hespan), and group 4, received 10 ml/kg Lactated Ringer's, and this was considered as the control group. All patients received the standard anesthetic technique. The incidence of PONV was recorded, two and 24 hours following surgery. The need for antiemetics and/or analgesics was recorded postoperatively. RESULTS: The highest incidence of PONV was in group 3 (75% of the patients) compared to the other three groups. Also the same trend was found with regard to the number of patients who needed antiemetic therapy. It was the highest incidence in group 3 (70%), followed by group 2 (60%), and then group 1(35%), and the least one was in the control group (25%). CONCLUSION: Intravascular volume deficits may be a factor in PONV and preloading with crystalloids showed a lower incidence of PONV.

Efficacy and safety of prophylactic large dose of tranexamic acid in spine surgery: a prospective, randomized, double-blind, placebo-controlled study.

STUDY DESIGN: This is a double blind randomized placebo controlled study, after obtaining approval of ethics committee in the hospital and informed written consent, 64 patients were randomized equally into 2 groups (tranexamic acid (TA) and placebo). OBJECTIVE: To evaluate efficacy and safety of large doses of TA on blood loss during spinal operations. SUMMARY OF BACKGROUND DATA: Blood loss associated with spinal operations is a common potential cause of morbidity and often requires blood transfusion which subject patients to the known risks of blood transfusion including transmission of diseases. TA is used routinely to reduce bleeding in cardiac, orthopaedic, and hepatic surgery, however, its use in neurosurgery is uncommon and only few studies reported the use of antifibrinolytic drugs in spine surgery. METHODS: Sixty-four consecutive patients undergoing spinal surgery with expected significant blood loss at King Khalid University Hospital between June 2005 and December 2006 were randomly assigned to 2 groups, TA and placebo. Shortly after the induction of anesthesia, patients received either TA or placebo as a loading dose of 2 g (for adults) or 30 mg/kg (for children), followed immediately by continuous infusion of 100 mg/h (for adults) or 1 mg/kg/h (for children) during surgery and for 5 hours after the operation. Outcome measures included total (i.e., intraoperative and postoperative) blood loss, amount of blood transfusion, as well as postoperative hemoglobin, and hematocrite levels. The data were analyzed by means of Statistical Package for the Social Science Version 12.0. The results were presented as mean +/- SD. Independent Student t test was used to compare the 2 groups and differences were considered significant if the P-value was <0.05. RESULTS: There were 39 males and 25 females, ranging in age from 4 to 86 years with a mean of 51 and median of 56 years. Eighteen patients had multilevel anterior cervical discectomies with or without internal fixation, 22 patients had decompressive surgery (12 laminectomies and 10 intersegmental decompressions) for multiseg- ment spinal stenosis, 15 patients had laminectomy with posterior spinal fixation, and remaining 9 patients had laminectomy and excision of spinal tumor. Statistical analysis showed no significant differences between the 2 study groups with regard to age, sex, weight, preoperative hemoglobin, and hematocrite levels, type of surgery, as well as operative time. In contrast, patients who received TA had 49% reduction of blood loss (P < 0.007) and required 80% less blood transfusion (P < 0.008) than patients who received placebo. The hospital stay was shorter in the TA group, but it did not achieve statistical significance. There were no complications related to the use of large doses of TA in this study. CONCLUSIONS: Prophylactic use of large doses of TA provides an effective, safe, and cheap method for reducing blood loss during and after spinal operations. Hence, TAmay help in reducing not only transfusion related complications but also operative expenses. Considering the limited number of patients in this study, our results need, however, to be validated on a larger number of patients, probably in a multicenter study.

Effect of bispectral index (BIS) monitoring on postoperative recovery and sevoflurane consumption among morbidly obese patients undergoing laparoscopic gastric banding.

UNLABELLED: Early and uneventful postoperative recovery of morbidly obese patients remains a challenge for anesthesiologists. It could be valuable to titrate the administration of inhaled anesthetic, such as sevoflurane, in morbid obese patients, in order to shorten emergence using bispectral index (BIS) monitoring. It would be a great advantage if BIS permitted a more rapid recovery and less consumption in morbidly obese patients with a high cost inhaled agent. The aim of the study is to show whether the titration of sevoflurane based on the BIS monitoring would allow shortening of recovery time in morbidly obese patients and to evaluate whether BIS monitoring would contribute to reduce the amount of sevoflurane administered while providing an adequate anesthesia. PATIENTS AND METHODS: Thirty morbidly obese ASA I & II patients undergoing laparoscopic gastric banding (LAGB) procedures were studied. In the first group (15 patients), patients were anesthetized without the use of BIS (non BIS or control group), and sevoflurane being administered according to standard clinical practice (control group). In the second group (15 patients), sevoflurane was titrated to maintain a BIS value between 40 and 60 during surgery, and then 60-70 during 15 min prior to the end of surgery (BIS group). Recovery times were recorded. Time to extubation was also noted, as well as the time to achieve a modified Aldrete score of 9 were evaluated subsequently at 10-min intervals until 3 h after surgery by nurses who had no knowledge of the study. Sevoflurane consumption was calculated using the vaporizer weighing method. RESULTS: Awakening and extubation times were significantly shorter in the BIS group (P < 0.05). In the BIS (vs. non BIS) group, there were no significant differences observed in the time to obtain an Aldrete score of 9. The sevoflurane consumption and cost in the BIS group were lower than in the non BIS group (P < 0.05). CONCLUSION: Bispectral index monitoring during anesthesia for morbidly obese patients provides statistically significant reduction in recovery times. It also has the added advantage in decreasing sevoflurane consumption.

Cardiodynamic monitoring during laparoscopic cholecystectomy.

With increasing success of laparoscopy, the hemodynamic changes associated pneumoperitoneum (PPM) was described using invasive and non-invasive techniques with variable results. In the present study, we have used non-invasive cardiodynamic monitor to investigate the hemodynamic changes during laparoscopic cholecystectomy. Eleven patients who underwent laparoscopic cholecystectomy under general anesthesia were studied. Cardiodynamic monitor (thoracic bioimpedance) was used to investigate the hemodynamic changes. The following parameters were continuously monitored: Heart Rate (HR), mean arterial blood pressure (MAP), cardiac output (CO) and cardiac index (CI). For statistical purpose, five phases were identified: (A), pre-PPM, (B), 2 min post-PPM, (C), 10 min post-PPM, (D), 30 min post-PPM, and (E), after gas deflation. SPSS package, Version 9 was used for statistical analysis of the data obtained. Student's t-test for paired observations was used for comparisons of the mean values of the data obtained, where P <0.05 was considered significant. There was significant change of the mean value of MAP in phases A and C. Also significant CI changes of the mean values was found between stages A and B (P <0.05). The study showed, transient cardiac depression immediately after PPM with partial recovery after ten min, which was associated with increase in MAP.

Variations in dynamic lung compliance during endoscopic thoracic sympathectomy with CO2 insufflation.

Endoscopic thoracic sympathectomy (ETS) is the preferred surgery for treatment of intractable palmar hyperhidrosis (PH). General anesthesia with onelung collapsed ventilation (OLCV) using single-lumen tracheal tube (SLT), is our preferred anesthetic technique for ETS. Intrapleural CO(2) insufflation (capnothorax) was used to ensure lung collapse. The current study examined the effects of capnothorax on dynamic lung compliance (DLC) of the ventilated lung during ETS. After obtaining written informed consent, 10 adult male patients ASA I&II undergoing ETS were studied. Their average age and weight were 25 +/- 7 yr and 67 +/- 8 kg. General anesthesia with SLT and OLCV technique was used. Capnothorax with intrapleural pressure (IPP) of 10 mmHg was initially used, then it was reduced and maintained at 5 mmHg throughout the operation. Anesthesia delivery unit (Datex Ohmeda type A_Elec, Promma, Sweden) was used where airway pressures and DLC were displayed during OLCV. A computer program (SPSS 9.0 for Windows; SPSS Inc., Chicago, IL) was used for statistical analysis of the data obtained. One way analysis of variance (ANOVA) was used for analysis of data before, during and after OLCV. P<0.05 was considered significant. The mean values of the DLC were 52 +/- 6, 30 +/- 3, 39 +/- 5 and 53 +/- 9 ml/cmH(2)O before, during (at 10 and 5 mmHg IPP) and after OLCV respectively with significant differences before and at 10 and 5mmHg IPP. In conclusions, during OLCV and capnothorax for ETS, DLC tends to decrease with increasing of intrapleural CO(2) insufflation pressure. However, in short procedures it has no deleterious postoperative effect. To the best of our knowledge this is the first study performed to investigate DLC changes during OLCV with capnothorax.