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

Model Number	X-DSG20L
Medical Device Problem Codes	Fracture (1260); Detachment of Device or Device Component (2907)
Health Effect - Clinical Code	Foreign Body In Patient (2687)
Date of Event	07/18/2025
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
The dentist refused to provide information about the patient's weight.Upon receiving the device involved in the mdr event from the distributor, nakanishi conducted a failure analysis of the returned device [report no.(b)(4)].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-dsg20l device [serial no.Head: (b)(6), shank: (b)(6)].There were no problems observed during manufacturing or testing noted in the dhr.The repair history showed 4 service records since the device was shipped.The repair details are as follows: june 2018: head: the cartridge was replaced.June 2018: shank: the glass fiber was replaced.February 2023: shank: the glass fiber was replaced.July 2023: head: the dog clutch was replaced.With respect to the repairs above, the service records indicate that nakanishi performed all of the necessary operation checks and confirmed that all of the criteria were met.B) nakanishi conducted a visual inspection of the returned device and observed the following: the dust-proof seal and a part of the cartridge were separated from the handpiece.The dust-proof seal was soiled and cracked.The broken parts of the cartridge were discolored and corroded.The tip of the head was discolored and corroded.Identification of the specific failure mode(s) and/or mechanism(s) of the associated device components was conducted as follows: a) nakanishi disassembled the handpiece and performed a visual inspection of the internal parts.Nakanishi observed the following: the bearing on the front side of the cartridge was broken.The cartridge and drive shaft were soiled and discolored.B) nakanishi took photographs of all the disassembled parts and kept them in the investigation report no.(b)(4).Conclusions reached based on the investigation and analysis results: a) nakanishi identified that the cause of internal parts separation was corroded cartridge breaking due to repeated cutting vibration.Nakanishi considers the possibility, from many years of experience and based on the findings in the visual inspection, that the causes of corroded cartridge were inadequate cleaning of the cartridge and deterioration over time.B) a lack of maintenance and use beyond the lifetime led to the above issue, which contributed to the reported event.C) in order to prevent a recurrence of the cartridge breaking/separation, nakanishi took the following actions: c.1) nakanishi reviewed the operation manual and reconfirmed the clarity and understandability of the instructions.C.2) nakanishi will report the above evaluation results to the distributor and directed the distributor to remind the user of the importance of maintenance as instructed in the operation manual.
Event or Problem Description
On july 25, 2025, nakanishi received a phone call from a distributor about a malfunction of a nsk handpiece.The details nakanishi obtained are as follows.The event occurred on (b)(6), 2025.A dentist was performing an implant placement procedure on a patient using the x-dsg20l handpiece (serial no.Head: (b)(6), shank: (b)(6)).The patient was under local anesthesia.During the procedure, the dentist found a piece of metal on the patient's tongue and removed it.The dentist checked the handpiece and bur but observed no abnormalities and continued with the procedure.After the procedure, a cbct scan was taken to confirm the implant position, and the dentist discovered a piece of metal on the outer side of the cortical bone of the lower jaw.On the same day as the incident, the dentist reopened the patient's incision, removed the piece of metal and re-sutured the wound.Another cbct scan was performed to confirm that the metal fragment had been removed.After the surgery, the dentist re-checked the handpiece and found that the internal parts of the handpiece were removed.

• Brand Name: NSK
• Common Device Name: HANDPIECE, ROTARY BONE CUTTING
• 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: sean kaufman ; 1800 global parkway; hoffman estates, IL 60192 ; 2245128921
• MDR Report Key: 22836809
• Report Number: 9611253-2025-00044
• Device Sequence Number: 9404344
• Product Code: KMW
• UDI-Device Identifier: 04560264528475
• UDI-Public: (01)04560264528475
• Combination Product (Y/N): N
• Initial Reporter Country: JA
• PMA/510(K) Number: K970953
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Foreign,Distributor
• Initial Reporter Occupation: Non-Healthcare Professional
• Type of Report: Initial
• Report Date (Section B): 08/19/2025

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
• Operator of Device: Health Professional
• Device Model Number: X-DSG20L
• Device Catalogue Number: C1068
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 07/28/2025
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 07/25/2025
• Initial Report FDA Received Date: 08/19/2025
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Date Device Manufactured: 05/18/2016
• Is the Device Labeled for Single Use? (Y/N): No
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Reuse
• Patient Sequence Number: 1
• Outcome Attributed to Adverse Event: Other
• Patient Age: 51 YR
• Patient Sex: Female
• Patient Ethnicity: Non Hispanic
• Patient Race: Asian