Failure characteristics of various arthroscopically tied knots

The current study evaluated multiple arthroscopic knot configurations and compared their properties with open, hand-tied square knots. This is an experimental study done on a material testing system. Number 2 Ethibond Extra and Number 1 Polydioxanone sutures were used. Four types of sliding knot configurations were tested: the Duncan loop, the Tennessee Slider, the Savoie-Modified Roeder, and the Lieurance-Modified Roeder. Two types of nonsliding knots were tested: the Revo knot and a knot consisting of alternating half-hitches tied with the Sixth Finger Knot Pusher. Ten knots were tied of each configuration, using strict arthroscopic technique. Each knot was backed-up with four half-hitches using post switching technique. Knots were tied around two rings and then transferred wet to a materials testing machine. The knots were tested until ultimate failure, with note of clinical failure at 3 mm. Ethibond suture using the Revo knot, the Lieurance-Modified Roeder knot, and the Savoie-Modified Roeder knot were similar in strength to the square knot with comparable failure modes. Polydioxanone suture was more variable; the Revo knot, the Savoie-Modified Roeder, the Tennessee Slider, and the Duncan loop were comparable with hand-tied square knots. All of the open and arthroscopic suture loops tested in this study failed by the suture loops expanding to greater than 3 mm before ultimate failure occurred. The surgeon choosing arthroscopic repair techniques should be aware of the differences in suture material and the variation in knot strength afforded by different knot configurations.     

A modified lightwand-guided nasotracheal intubation technique for oromaxillofacial surgical patients

Study ObjectiveTo investigate the efficiency of a double curve nasotracheal tube on lightwand-guided nasotracheal intubation.DesignProspective, randomized, controlled trial.SettingUniversity medical center hospital.Patients60 ASA physical status I and II patients undergoing oromaxillofacial surgery.Interventions and MeasurementsPatients undergoing surgery with nasotracheal intubation and general anesthesia were randomly enrolled in the laryngoscopy group or the lightwand group. The same type of double curve nasotracheal tube was used in both groups. In the laryngoscopy group, intubation was assisted with a Macintosh No. 3 standard curved blade and Magill forceps. In the lightwand group, intubation was aided with a flexible lightwand device (without the inner stiff stylet). Intubation time was divided into two parts: Part one, from selected naris to oropharynx; Part two, from oropharynx into trachea. Part one, Part two, and total intubation time, hemodynamic responses to nasotracheal intubation, and adverse events or complications were recorded.Main ResultsTotal intubation times in the lightwand group and the laryngoscopy group were 22.8 ± 8.0 sec vs 30.3 ± 8.2 sec (P < 0.001), respectively. The lightwand group had comparable hemodynamic responses to those of the laryngoscopy group. Adverse events and complications were all self-limited, with similar occurrence in both groups.ConclusionFor patients undergoing oromaxillofacial surgery, modified lightwand-guided nasotracheal intubation is feasible with a double curve nasotracheal tube and is an efficient alternative technique.     

Simultaneous carotid and coronary disease: safety of the combined approach

Invoking unacceptable operative risks, many institutions have adopted a conservative policy toward carotid stenosis in patients who require cardiopulmonary bypass (CPB). We have continued to apply simultaneous carotid endarterectomy/coronary artery bypass grafting (CEA/CABG) in selected patients, and in order to place operative risk in perspective, our experience with CEA/CABG was reviewed and contrasted with both CEA and CABG performed as isolated procedures. Seventy-one CEA/CABG were performed from 1978 to 1987, with the bulk of the experience (51/71) accumulated over the past 5 years. CEA/CABG was applied when the carotid lesion was severe (greater than or equal to 75% diameter stenosis). Clinical characteristics of patients with CEA/CABG (e.g., presence of unstable angina, left main coronary artery disease, and impairment of ventricular function) suggested these patients were at higher risk for complications when compared to patients with CABG alone. Yet, other factors influencing stroke risk during cardiopulmonary bypass (patient age, duration of CPB time) were similar between patients with CEA/CABG and patients with only CABG. Most complications in patients with CEA/CABG occurred in the early years of the study. Considering the recent (1983-87) patient cohorts of CEA/CABG and isolated CABG, respectively, there was no significant difference in either operative mortality (2.0% as compared to 2.2%) or perioperative stroke (2.0% as compared to 0.6%). Whereas precise patient selection criteria remain undefined, these findings verify the safety of the combined CEA/CABG approach for most patients who require treatment of both lesions.     

Evaluation of smear layer removal by bicarbonate soda,ethylenediamine tetraacetic acid with cetrimide and sodium hypochlorite with a new model

Various methods are used to evaluate irrigants. The primary aim was to develop a model for preliminary testing of potential irrigants. The second aim was to investigate the effect of bicarbonate soda on smear layer by comparing it with ethylenediamine tetraacetic acid with cetrimide (EDTAC) and sodium hypochlorite (NaOCl). Extracted human single‐canal teeth were halved, and a uniform filing method was used to create smear layer. The following solutions were then applied – distilled water (control), 1% NaOCl, 17% EDTAC and bicarbonate soda at concentrations of 1%, 5%, 10% and 15%. Some samples had multiple solutions in different sequences. Samples were examined by scanning electron microscopy. Representative images were scored based on the degree of smear layer remaining. Results were analysed with the SAS system, using the GENMOD procedure. Complete smear layer was found in samples treated with all solutions except EDTAC used alone. There were no significant differences between the sequences, EDTAC/NaOCl/EDTAC and NaOCl/EDTAC/NaOCl. There were no significant differences between groups with and without bicarbonate soda. In conclusion, the model was effective for testing chemical effects on solutions on smear layer. Bicarbonate soda did not remove smear layer and provided no additional cleaning effects after EDTAC and NaOCl.     

Comparison of urine, first and second endourethral swabs for PCR based detection of genital Chlamydia trachomatis infection in male patients

OBJECTIVES: To compare endourethral swabs and urine as diagnostic specimens for the detection of genital Chlamydia trachomatis infection using the polymerase chain reaction (PCR), in male patients attending a genitourinary clinic and to assess whether the first endourethral swab used solely for diagnosing gonococcal infection could be used for C trachomatis detection as well. METHODS: Two endourethral swabs were taken from 80 male patients, in whom the likelihood of genital C trachomatis infection was high. The first swab was used for microscopy and culture for Neisseria gonorrhoeae, before being used for C trachomatis detection. First voided urine specimens were collected from 61 of these patients. All three specimens were processed for C trachomatis DNA detection using the Roche Cobas Amplicor PCR. A diagnosis of genital C trachomatis infection was made if any one of the specimens tested reproducibly positive. Samples from 13 patients showing discrepant PCR results between swabs and/or urine were retested by ligase chain reaction (LCR). RESULTS: Chlamydia trachomatis DNA was detected in 35 (43.8%) of the 80 patients. In 17 of the 35 patients (48.6%), all the genital specimens were positive. However, in 18 (51.4%) patients, one or more of the genital specimens had negative PCR results. Among the 18 patients with discrepant results, urine was found to be a more sensitive diagnostic specimen than the second urethral swab picking up 13 out of 16 positives (81.3%) as opposed to five out of 18 (27.8%). There was no significant difference between the two swabs. Retesting by LCR, of the samples from 13 of the 18 patients with discrepant PCR results confirmed them all as true positives, although as with PCR, not all specimens in the set were concordantly positive. LCR detected all the 13 positives in urine, while there was no difference in the detection rate between the first and the second urethral swabs. CONCLUSIONS: Urine appeared to be a better diagnostic specimen than the conventional second endourethral swab for C trachomatis detection by PCR in this cohort of male patients. There was no difference between the first swab, intended primarily for N gonorrhoeae testing and the second swab intended for C trachomatis detection. This raises questions over the need for the conventional second swab for detecting C trachomatis.