MAUDE Adverse Event Report: NAKANISHI INC. NSK

Model Number SGA-E2S

Device Problem Overheating of Device (1437)

Patient Problem Full thickness (Third Degree) Burn (2696)

Event Type  Injury  

Event Description

This mdr is being reported at this time as part of our internal review of past complaints and service records.Due to the incident being in the past, we are limited in the info that we can obtain from the initial complainant.Nakanishi received the info about a patient's burn injury due to overheating of the handpiece.Several days later, nakanishi received details about the event as follows: the pt was burned on the right corner of the lip.It took a longer time to be aware of the burn because the pt was anesthetized.The pt suffered a third-degree burn.The pt did not go through an operation right after the event, the pt was not ready for the operation.

Manufacturer Narrative

Upon receipt of the device involved in the mdr event, nakanishi conducted a failure analysis of the returned device that included measurement of the temperature of the operating device.These activities are described in more detail below: methodology used: nakanishi conducted a visual inspection of the returned device and performed a simple movement test.There were no visible abnormalities, such as cracks or debris, on the outside of the handpiece.Nakanishi then set a test bur in the handpiece and rotate it by hand to see bearing condition.Nakanishi observed that the bur did not rotate smoothly.Then, nakanishi carried out temperature testing.Temperature sensors were first attached to the exterior of the device at various test points (e.G., most proximal to the pt and along points farther toward the distal end of the device).The test setup was prepared to take temperature measurements at all points simultaneously.Nakanishi attached a thermocouple (sensor to measure a temperature) to each of the testing points, the bur-guide earing area, the shaft retainer bearing area and the gear area.Nakanishi rotated the handpiece at a maximum speed of 40,000min-1, and measured the exothermic situation.Nakanishi measured the temperature rise of the returned handpiece set at 40,000min-1.Nakanishi confirmed a maximum temperature of 68 degrees c at the bur-guide bearing area 5 minutes after the beginning of the measurement, which is outside nakanishi specification.Identification of the specific failure mode(s) and/or mechanism(s) and the associated device component(s) involved: nakanishi disassembled the handpiece and performed a visual inspection of the inside parts.Slight corrosion and dirt were observed on the inside parts.Nakanishi also confirmed rough surface of the balls and the raceway of the bur-guide bearing through a microscope.Conclusions reached based on the investigation and analysis results: nakanishi identified that the cause of overheating of the returned device was due to damage to the bearing.The damage observed caused abnormal rotation resistance, which would result in the handpiece overheating.The damage observed is consistent with a lack of proper lubrication and cleaning after use.A lack of maintenance causes the bearing ot become damaged, which will contribute to the handpiece overheating.In order to prevent the recurrence, nakanishi reminded the operator of the cautionary statement included in the user manual.

• Brand Name: NSK
• Manufacturer (Section D): NAKANISHI INC.; 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• Manufacturer (Section G): NAKANISHI INC.; 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• Manufacturer Contact: kenneth block ; 800 e campbell rd.; suite 202; richardson, TX 75081 ; 9724809554
• MDR Report Key: 4805593
• MDR Text Key: 20756229
• Report Number: 9611253-2015-00079
• Device Sequence Number: 1
• Product Code: KMW
• Combination Product (y/n): N
• Reporter Country Code: JA
• PMA/PMN Number: K970953
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Distributor,distributor
• Reporter Occupation: Other
• Remedial Action: Recall
• Type of Report: Initial,Followup
• Report Date: 07/10/2018

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 05/26/2015
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Other
• Device Model Number: SGA-E2S
• Device Catalogue Number: H265
• Was Device Available for Evaluation?: Yes
• Date Returned to Manufacturer: 08/31/2012
• Is the Reporter a Health Professional?: No
• Date Manufacturer Received: 06/09/2018
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 08/03/2007
• Is the Device Single Use?: No
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Reuse
• Removal/Correction Number: 9611253-060818-001-R
• Patient Sequence Number: 1
• Patient Outcome(s): Other