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

Model Number SGS-E2S

Device Problem Overheating of Device (1437)

Patient Problem Burn(s) (1757)

Event Date 09/04/2020

Event Type  Injury  

Manufacturer Narrative

The distributor is attempting to obtain further information on the event, including information about the patient.Upon receiving the device involved in the mdr event from the distributor, nakanishi conducted a failure analysis of the returned device (b)(4).These activities are described in more detail below.Methodology used: nakanishi examined the device history record and the repair history for the subject sgs-e2s device [serial number: (b)(4)].There were no problems observed during the manufacturing or testing noted in the dhr.There were also no repair history records since the device was shipped.Nakanishi set a test bur in the handpiece, connected the handpiece to the motor, and tried to rotate the motor.However, the handpiece was locked and the motor did not rotate at all.Therefore, nakanishi was not able to conduct temperature testing of the device.Identification of the specific failure mode(s), and/or mechanism(s) of the associated device components was conducted as follows: nakanishi disassembled the handpiece and performed a visual inspection of the internal parts.Nakanishi observed the following phenomena: the gear shaft did not rotate at all.There was debris on the bearing.The internal parts were corroded.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: nakanishi could not replicate the temperature increase from the event, but based on the findings in the visual inspection, as well as many years of experience, nakanishi identified the cause of the handpiece overheating was abnormal resistance during rotation due to the soiled bearing caused by ingress of foreign materials into the handpiece.A lack of maintenance causes the accumulation of debris on the inside parts, which causes debris ingress into the bearing during rotation.This contributes to the handpiece overheating.In order to prevent a recurrence of the handpiece overheating, nakanishi took the following actions: nakanishi reviewed the operation manual, reconfirmed clarity, and understandability of the instructions.Nakanishi reported the above evaluation results to nsk america and directed nsk america to remind the user of the importance of maintenance, as instructed in the operation manual.

Event Description

On october 3, 2020, nakanishi became aware of a handpiece overheating through a complaint input into the complaint database by a distributor (nsk america).Details are as follows: the event occurred on (b)(6) 2020.A dentist was performing a dental procedure on a patient using the sgs-e2s handpiece (serial no.: (b)(4)).During the procedure, the handpiece overheated and burned the patient's inner cheek.

Manufacturer Narrative

On (b)(6) 2020, nam updated nakanishi about the event.Despite the following attempts, nam received no response from the dentist.On (b)(6) 2020, nam made a phone call to the dental office for detailed information about the event.Nam left a voicemail message requesting the dental office to contact nam.On (b)(6) 2020, nam called the office again and left another message on the voicemail.On (b)(6) 2020, nam sent an e-mail to the dentist requesting the details.On (b)(6) 2020, nam sent another e-mail to the dentist.

• 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: 10732463
• MDR Text Key: 216112379
• Report Number: 9611253-2020-00040
• Device Sequence Number: 1
• Product Code: KMW
• Combination Product (y/n): N
• PMA/PMN Number: K171155
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative
• Remedial Action: Recall
• Type of Report: Initial,Followup
• Report Date: 01/14/2021

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: SGS-E2S
• Device Catalogue Number: H266
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 10/14/2020
• Initial Date Manufacturer Received: 10/03/2020
• Initial Date FDA Received: 10/26/2020
• Supplement Dates Manufacturer Received: 12/19/2020
• Supplement Dates FDA Received: 01/13/2021
• Is This a Reprocessed and Reused Single-Use Device?: No
• Removal/Correction Number: 9611253-060818-001-R
• Patient Sequence Number: 1
• Patient Outcome(s): Other