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Initial report filing in accordance with 30 day requirement from becomes aware date.The user reported the event as "inadequate water flow from hand piece resulting in thermal injury to wound bed." the planned medical procedure to be performed on the patient was debridement and skin graft to a minor burn to left foot.The report is for a patient burn.No death was reported.No deterioration of patient health was reported.No injury resulting in permanent damage to body structure was reported.The user determined that medical intervention was required to prevent permanent impairment of body structure damage, in that the planned medical procedure was "to debride the burn site and apply a piece of artificial skin.Had to take an autograft instead.", as reported by user.The user was issued a return material authorization ((b)(4)) to return the [e-sogen-or] sonicone or ultrasonic generator and accompanying bcm-hp bonescalpel handpieces for evaluation.The returned bcm-hps, serial (b)(4) were evaluated.Both handpieces met specification and no problem was found with either device.The [e-sogen-or] sonicone or ultrasonic generator, serial (b)(4), evaluation is ongoing as of the date of this filing.A follow-up report will be submitted at a later date.
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This report is the follow-up report to the initial filing of (b)(4).The complaint was a malfunction of a sonicone or ultrasonic generator, e-sogen-or, serial number (b)(4).The date of the initial report was (b)(6) 2018.The date of the event was reported as (b)(6) 2018.The customer stated event was "inadequate water flow from the handpiece resulting in thermal injury to wound bed".Therefore, we interpret this event to be a patient burn.The following information was not reported: the degree of the patient burn.Deterioration of the state of health of the patient.Permanent impairment of body function or damage to body structure.Delay in treatment.Extended hospital stay beyond the expected time of stay.Death.The patient was a 37 year old male, 5.5' in height, 196.6lbs, with a medical history of a 1% second degree burn to left foot.The surgical procedure performed was debridement of and skin graft over the affected area.Reporter indicated the settings used on the generator were: [amplitude = 7], [flow = 70%] and [pulse = 100%].The settings are the default settings for the equipment.The reporter stated a malfunction occurred within the handpiece causing the adverse event.Reporter requested return material authorization for the genrator, and misonix requested the handpiece used during the event be returned as well.The handpieces bcm-hp, serial number (b)(4).And generator e-sogen-or serial number (b)(4).Were returned, inspected, tested, with the following technical findings: generator initial observation: visual inspection found the lower v-clamp of the peristaltic pump head completely closed, crimping the irrigation tubing.Upon power up of the generator the factory default settings were found to be changed to: [amplitude = 10], [pulse = 100%], [flow = 35%] pump motor making minor bearing noise both v-clamps should be in the fully open position.Testing performed: performed generator functional test and calibration, pump flow calibration testing per section 2.4 of sm-801 appendix b rev.X.Test results with original pump motor low end spec.= 15ml +/- 3ml result clamp closed: 11ml result clamp open: 20ml won't hold adjustment failed midrange spec.= 29ml +/- 4ml result clamp closed:25ml result clamp open: 60ml won't hold adjustment failed high end spec = >67ml result clamp closed:30ml result clamp open: 80ml won't adjust replaced motor, worn bearings.Test results with new replacement motor: low end spec.= 15ml +/- 3ml per min result = 16ml test passed midrange spec.= 29ml +/- 4ml per min result = 30ml test passed high end spec = >67ml per min result = 74ml pass passed successfully completed all remaining sub-tests within the sonicone-or generator sm-801 appendix b rev x functional test and calibration hand piece initial observation: both hand pieces passed functional test wi-10-227 and safety test stm-09-04 and were within specification with no nonconformance.The service department report indicates that the generator was being operated outside the default settings, which are also the recommended settings in the ifu.The default settings are an amplitude of 7 and an irrigation setting of 70%.The returned generator was observed to have an amplitude of 10 which represents a 50% increase in amplitude over the default settings and a irrigation setting of 35% which is half of the recommended setting of 70%.Changes to the system by the user resulting in operation of the medical device outside recommendations, coupled with v-clamps not in full open position, will result in the handpiece having an elevated temperature at the tip.The sonicone instructions for use manual revision m includes the following warnings with regard to use and surgical technique: warning 3.1: tip and irrigant temperatures may exceed the tissue necrosis point if insufficient irrigation flow rates are used.For hard tissue removal, set the irrigation flowrate to a setting no less than the comparable vibration setting.For example, if the vibration setting is 7, a minimum flow setting of 70% should be used.Additional external irrigation, e.G.By administering sterile saline with a syringe over the distal tip portion, may be necessary for removal of very dense, hard osseous structures.Warning 3.2: tissue necrosis may result if tip is not moved relative to tissue.A continuous, lateral sweeping motion is recommended in order to minimize contact duration with the ultrasonic tip and minimize heat build-up.When lateral motion is not possible withdraw and re-insert tip frequently.Warning 7.3: tip and irrigation temperatures may exceed the tissue necrosis point with sonicone o.R.Accessories for hard tissue removal if insufficient irrigation flow rates are used.Always set the irrigation flowrate for hard tissue removal to a setting no less than the comparable vibration setting.For example, if the vibration setting is 7, a minimum flow rate setting of 70% should be used.Warning 7.4: heat is being generated at the tip/tissue interface.A continuous, lateral sweeping notion is recommended for general bone/tissue removal in order to minimize contact duration with the ultrasonic tip and minimize temperature increase.The device history record for the generator was reviewed.All manufacturing and testing procedures were in conformance with requirements.All test results were in conformance with requirements.Trend analysis for sonicone system was conducted.The defective rate is based on the number of procedures performed during that time period june 5, 2017 through june 5, 2018, which in turn is estimated by the install base.There were no other reports a patient burn caused by a generator.There are 327 sonicone systems in commerce at the time of this report.The percent defective is 0.91 %.There are no adverse trends noted.The complaint rate is below the rate estimated in the original risk assessment.Therefore, there is no change in risk probability, residual risk, or risk-benefit ratio.Conclusion: the degree of the patient burn was not reported.User indicated that the planned procedure was to debride the original burn site and a ply a piece of artificial skin, however due thermal injury at would site an autograft was performed instead.A potential root cause was thermal equilibrium caused by high amplitude and low irrigation flow rate caused by the default settings to be changed.The sonicone ifu contains adequate warnings for tissue necrosis caused by heat build-up and the proper technique to be used to avoid heat buildup.
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