Reprocessed arthroscopic shavers: evaluation of sharpness and function in a cadaver model.

This study was designed to test limited arthroscopic shaver reuse following reprocessing and to compare the functional performance between new and reprocessed arthroscopic shavers in arthroscopic procedures using fresh cadaveric knees. A trial using arthroscopic procedures (menisectomy, synovectomy, and debridements) was conducted by experienced surgeons using cadaveric knees to determine whether the surgeons could correctly identify reprocessed shavers. Thirty-nine shavers were tested; the surgeons were given both new and reprocessed shavers. Thirteen of the 39 shavers were new and 26 were reprocessed (13 of which had also been sharpened). The surgeons were asked to assess whether each shaver was new or reprocessed and to indicate whether the shaver was functional or not. Cadaveric shavers were subsequently used in an engineering test developed to measure shaver blade sharpness. Comparisons in sharpness were made between new and reprocessed cadaveric shaver blades. The success rate in identifying reprocessed shavers was determined to be 42% (11 of 26), with an upper confidence bound of 60%, demonstrating that the ability to detect a reprocessed shaver is no better than chance (50%), with a margin of error of 10% (P=.0328). In addition, engineering sharpness testing demonstrated that new and reprocessed cadaveric blades exhibit equivalent sharpness. Surgeons were unable to distinguish reprocessed arthroscopic shavers that passed acceptance tests from new shavers based on functional characteristics. This outcome is not unexpected due to the fact that engineering testing of shaver blades used in the study indicated that they exhibited similar sharpness.

Comparison of in vivo clinical performance and shaft temperature and in vitro tissue temperature and transection times between new and reprocessed harmonic scalpels.

The ultrasonic harmonic scalpel (HS) uses ultrasound energy to achieve surgical dissection. To test the feasibility of limited HS reuse and to insure that reprocessed HS function in a substantially equivalent manner to their new counterparts, this study compared in vivo mesenteric vessel and liver cutting characteristics, scalpel shaft temperatures during in vivo usage and in vitro tissue temperature dissipation characteristics between new and reprocessed ACE™36 series HS. The study found that new and reprocessed ACE™-36 HS exhibit identical performance with respect to in vivo dissection characteristics and postcut shaft temperatures. The in vitro studies show tissue temperature elevations and durations adjacent to dissection sites to be substantially equivalent for reprocessed versus new devices. Finally, cut times and extended use performance for new and reprocessed devices exhibit no statistical differences. We conclude that reprocessed HS scalpels that pass acceptance tests exhibit functional and safety capabilities that are equivalent to their new counterparts.

Reprocessing and sterilization of single-use electrophysiological catheters: removal of organic carbon and protein surface residues.

Although evidence to date indicates that reprocessing electrophysiological (EP) catheters results in clean, sterile devices, some concerns persist with regard to the risk of residual contamination. We examined the ability of a defined reprocessing procedure coupled with a validated sterilization protocol to remove organic carbon and protein residues from worst-case soiled EP catheters resulting in clean, sterile devices. Total organic carbon (TOC) determinations indicated that detergent residues on reprocessed used catheters were nominal and significantly lower than organic carbon levels present on new catheters. Determination of the mean residual organic carbon and protein contaminants on soiled and reprocessed EP catheters further indicated that TOC and protein were reduced (> or =99% of residue removed) below previously reported levels and current accepted standards. Moreover, reprocessed end-of-life catheters (six clinical uses, plus five reprocessings) were examined for residual microorganisms and found to be sterile. End-of-life catheters that had been inoculated with >10(6) CFU Bacillus atrophaeus spores and subjected to a half-cycle ethylene oxide exposure were also found to be sterile. Our data indicate that EP catheter cleaning and reprocessing using defined protocols effectively removes detergent residues and biological contamination, and provides sterile devices.

Acceptance criteria for reprocessed AcuNav catheters: comparison between functionality testing and clinical image assessment.

The AcuNav-catheter is a vector-phased array ultrasound catheter that has shown great utility for both diagnosis and electrophysiological interventions. To test the feasibility of limited catheter reuse and to ensure that reprocessed catheters would produce acceptable clinical images, the present study compared the 2-D and Doppler image quality, as determined by clinical assessment, with the catheter's functional status as determined by the FirstCall 2000 transducer tester. Reprocessed catheters from four functional categories, two acceptable and two unacceptable, were used to collect images, 2-D and Doppler, from a porcine heart. The images were blinded and then rated by clinical evaluation. The study found that catheter images from all functional categories were found to be clinically acceptable except for those from the lowest unacceptable category. In addition, examination of tip deflection characteristics showed no significant difference between new and reprocessed catheters. We conclude that reprocessed AcuNav catheters that pass functional tests are able to produce clinical images, 2-D and Doppler, which are equivalent to their new counterparts.

Comparison of performance characteristics between new and reprocessed electrophysiology catheters.

OBJECTIVE: Electrophysiology (EP) catheter reprocessing is widespread and previous studies have examined clinical performance, sterility and safety of these reprocessed devices. Here we compare the intrinsic engineering characteristics, electrical, mechanical and safety, between new and reprocessed devices. MATERIALS AND METHODS: New (58 devices) and clinically used (five times)/reprocessed (165 devices) EP catheters from five manufacturers were employed to examine and compare catheter electrode continuity, electrode isolation, electrical leakage current, shaft torsion and stiffness characteristics as well as tip buckling and bond strengths. RESULTS: Electrode continuity, isolation and leakage currents for both new and reprocessed EP catheters were within acceptance criteria for electrode continuity (<30 Omega) and shaft electrical leakage (<0.5 mA) as well as electrode isolation (>200 Omega). In addition, reprocessed catheters were equivalent when compared with their new counterparts. While catheter shaft torque forces varied five fold amongst manufacturers, comparison between new and reprocessed devices within a manufacturer showed no significant differences. Likewise shaft stiffness showed no significant difference between new and reprocessed devices. Average tip buckling forces for all catheters were substantially below the acceptance criteria of 0.45 lb (between 0.04 and 0.1 lb) with differences between new and reprocessed catheters not being significant. All bond strengths for both new and reprocessed catheters exceeded the acceptance criteria specified in ISO 10555-1. CONCLUSIONS: This study found that reprocessed EP catheters which had undergone five actual clinical use/reprocessing cycles met and exceeded acceptance criteria specified by industry standards as well as individual manufacturer's criteria for both electrical and safety characteristics. We conclude that reprocessed EP catheters exhibit electrical, mechanical and safety characteristics which are equivalent to their new counterparts.

Antinociception following implantation of mouse B16 melanoma cells in mouse and rat spinal cord.

B16 F1C29 melanoma cells, which are thought to contain and release catecholamines, were implanted in mouse and rat spinal subarachnoid space. B16 F1C29 cell implants augmented the antinociceptive effect of morphine in tail-flick test, and this interaction was blocked by either the alpha 2-adrenergic antagonist idazoxan or the opioid antagonist naloxone. B16 F1C29 cell implants also augmented the antinociceptive effect of the catecholamine re-uptake blocker desipramine. Substance P-induced biting and scratching behaviors were inhibited in mice receiving B16 F1C29 cell implants, and this effect of B16 F1C29 cell implants was blocked by the alpha 2-adrenergic antagonist idazoxan. Mice receiving B16 F1C29 cell implants showed tolerance to intrathecal administration of the alpha 2-adrenergic agonist UK 14304. These results suggest that B16 cell implant-induced antinociception was mediated by catecholamines secreted from the cell implants and acting at spinal alpha 2-adrenergic receptors. Spinal implantation of catecholamine-releasing cells may provide an alternative approach for the therapy of chronic intractable pain and a useful model to study alpha 2-adrenergic receptor tolerance.