MAUDE Adverse Event Report: NAKANISHI INC. NSK; HANDPIECE, ROTARY BONE CUTTING

Model Number X-SG65L

Device Problems Failure to Deliver Energy (1211); Overheating of Device (1437); Temperature Problem (3022); Noise, Audible (3273)

Patient Problems Burn(s) (1757); Injury (2348); Burn, Thermal (2530); Patient Problem/Medical Problem (2688)

Event Date 03/01/2019

Event Type  Injury  

Manufacturer Narrative

Nakanishi is still trying to obtain missing information about the patient.

Event Description

On march 14, 2019, nakanishi received an e-mail from a distributor ((b)(4)) about a handpiece overheating.According to the distributor, one of the x-sg65l handpieces (serial no.(b)(4)) overheated and caused the following event, but the dentist could not identify which devices actually overheated.The details of the event are: the event occurred on (b)(6) 2019.The surgeon was removing the 3rd molar of the patient's lower right jaw using the x-sg65l handpiece.The patient was under anesthesia.During the procedure, the handpiece suddenly made an abnormal noise and stopped.The dentist noticed that oil had gotten onto his/her gloves and onto the patient's upper left lip.When removing the handpiece from the patient's mouth, there was a burn on the patient's lip.The surgeon immediately stopped the surgery, irrigated the wound and applied (b)(6) to the area.The surgical procedure was completed with another handpiece, as the handpiece involved in the event was no longer functioning.The surgeon reported that there was significant oil coming out of the handpiece when the device was cleaned by the staff later.The surgeon consulted other medical staff in the hospital, and the head of plastic surgery recommended kenalog in orobase.The hospital determined that no immediate burn treatment was necessary and that the hospital would conduct a follow-up with the patient.Nakanishi is submitting two separate mdrs for this event based on the information from the distributor.This mdr is regarding the handpiece with the serial number (b)(4).

Manufacturer Narrative

Upon receiving the device involved in the mdr event from the distributor, nakanishi conducted a failure analysis of the returned device that included measuring the operating temperature of the device [c190314-03].These activities are described in more detail below.Methodology used: a) nakanishi examined the device history record and the repair history for the subject x-sg65l device [serial number 0bh90064].There were no problems observed during manufacturing or testing noted in the dhr.There were also no repair history records since the device was shipped.B) nakanishi conducted temperature testing of the returned device in the following manner: b.1) temperature sensors were attached to the exterior of the device at various test points.This included the point most proximal to the patient (testing point (1)) and points further toward the distal end of the device (testing points (2) through (4)).The test setup was prepared to take temperature measurements at all points simultaneously, including a reference measurement at ambient room temperature.B.2) nakanishi attached a thermocouple (sensor to measure temperature) to each of the testing points.Nakanishi rotated the device's motor at 40,000 min-1, which is the maximum rpm for the motor that drives the handpiece (40,000 min-1 for the handpiece), without water spray, and measured the exothermic response.B.3) nakanishi measured the temperature rise of the returned handpiece set at 40,000 min-1 (motor revolution 40,000 min-1).Nakanishi observed rises in temperature at the testing points as shown below; however, the temperatures were not high enough to cause a burn injury.Temperature measurement 5 minutes after the start are as follows: - test point (1): 40.0 degrees c - test point (2): 36.4 degrees c - test point (3): 35.2 degrees c - test point (4): 34.2 degrees c identification of the specific failure mode(s) and/or mechanism(s) and the associated device components involved: a) nakanishi disassembled the handpiece and performed a visual inspection of the inside parts.Nakanishi observed the following phenomena: - there was debris and abraded balls in the ball bearing.- there was debris and corrosion on the other parts.B) nakanishi took photographs of all of the disassembled parts and kept them in the investigation report #(b)(4).Conclusions reached based on the investigation and analysis results: 1) nakanishi could not replicate the temperature rise at the time of the event, however based on abnormality in the inside parts observed in the visual inspection, as well as many years of experience, nakanishi identified that the cause of the overheating of the returned device was abnormal resistance during rotation caused by the corroded and soiled inner parts.2) a lack of maintenance causes corrosion and of debris on the inside parts, which contributes to the handpiece overheating.3) in order to prevent a recurrence of the handpiece overheating, nakanishi took the following actions: 3.1) nakanishi reviewed the operation manual and reconfirmed the clarity and understandability of the instructions.3.2) nakanishi reported the above evaluation results to nsk oceania and directed nsk oceania to remind the user of the importance of maintenance and checking of the handpiece prior to use to prevent overheating, as instructed in the operation manual.

• Brand Name: NSK
• Type of Device: HANDPIECE, ROTARY BONE CUTTING
• Manufacturer (Section D): NAKANISHI INC.; 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• MDR Report Key: 8484700
• MDR Text Key: 141052098
• Report Number: 9611253-2019-00021
• Device Sequence Number: 1
• Product Code: KMW
• Combination Product (y/n): N
• PMA/PMN Number: K970953
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative,foreig
• Type of Report: Initial,Followup
• Report Date: 04/18/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 04/04/2019
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: X-SG65L
• Device Catalogue Number: H1009
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 03/20/2019
• Date Manufacturer Received: 04/02/2019
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 25 YR
• Patient Weight: 57