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

Model Number SGS-E2S

Device Problems Overheating of Device (1437); Device Operates Differently Than Expected (2913); Temperature Problem (3022)

Patient Problems Burn(s) (1757); Superficial (First Degree) Burn (2685); Nervous System Injury (2689); Partial thickness (Second Degree) Burn (2694)

Event Date 08/05/2016

Event Type  Injury  

Manufacturer Narrative

(b)(4).The information received from (b)(4) is as follows: the handpiece was sent in to (b)(4).The handpiece arrived at (b)(4) on august 10, 2016.There were no incoming comments indicating patient involvement.Repair history review was conducted on the handpiece sgs-e2s (serial number (b)(4)).The handpiece was at (b)(4) for repair on march 14, 2016, may 26, 2016 and july 21, 2016.An evaluation of the repair records on march 14, 2016 found that the cause of issue was heavy internal corrosion which locked up the gears and bearings.An evaluation of the repair on may 26, 2016 found corrosion within in the internal system.An evaluation of the repair on july 21, 2016 found that corrosion had formed on the internal parts as a result of blood that had not been completely cleaned out of the handpiece.On august 12, 2016, (b)(4) contacted the dental office to request additional patient information.The request for additional information was not made available to (b)(4).The dental office would not offer any further information in written or verbal communication.

Event Description

On august 15, 2016, nakanishi received an email from a distributor ((b)(4)) describing a burn to a patient.Details are as follows: on august 10, 2016, (b)(4) was made aware of an unconfirmed patient burn by an nsk sales representative.The dentist stated that the handpiece had burnt a patient.(b)(4) forwarded the nsk patient information form to the dentist to supply information on the experience.2) (b)(4) received the patient information form from the dentist on august 12, 2016 by email, and details are as follows.The dentist stated that the burn was on the lip.The patient received a 1st and 2nd degree burn.

Manufacturer Narrative

Upon receiving the device involved in the adverse event, nakanishi conducted a failure analysis of the returned device: methodology used: nakanishi examined the device history record for the subject sgs-e2s device (serial number (b)(4)).There were no problems observed during the manufacturing or testing noted in the dhr.Nakanishi conducted a visual inspection of the returned device and performed a simple movement test.- nakanishi set a test bur in the handpiece and rotated it by hand.Nakanishi observed a rotational resistance.- nakanishi did not observe any damage on the exterior.Investigation of overheating: temperature sensors were first attached to the exterior of the device at various test points (i.E.Most proximal to the patient, testing point (1), and along points further toward the distal end of the device, testing points (2) through (4)).The test was set up to take temperature measurements at all points simultaneously, including a reference measurement at ambient room temperature.Nakanishi attached a thermocouple (sensor to measure temperature) to each point.Nakanishi rotated the motor at 40,000 min-1, which is the maximum rpm for the motor that drives the handpiece (80,000 min-1 for the handpiece), and measured the exothermic situation.) nakanishi observed abnormal temperature rises at test points (1) through (4) 300 seconds after the start.Temperature measurements 300 seconds after the start are as follows: - test point (1): 68.6 degrees c - test point (2): 75.2 degrees c - test point (3): 69.0 degrees c - test point (4): 78.9 degrees c the temperature testing was conducted for the full 5 minute evaluation.Nakanishi washed the inside of the handpiece using nakanishi pana spray plus, as defined in the operation manual.Nakanishi observed dirt/debris being expelled from the head of the handpiece by using a white filter to catch anything that was expelled.Nakanishi measured the temperature rise of the handpiece cleaned using pana spray plus the way described.Nakanishi did not observe abnormal temperature rising during the test period.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.Nakanishi observed that the bearings were corroded and dirty.Nakanishi took photographs of all of the disassembled parts and kept them in a file.Conclusion reached based on the investigation and analysis result: nakanishi identified that the cause of the overheating of the returned device was abnormal resistance during rotation caused by dirt/debris in the bearings.A lack of maintenance causes the accumulation of dirt (abrasive powders/foreign materials) in the inside parts, which causes dirt/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 and reconfirmed clarity and understandability of the instructions.Nakanishi reported the above evaluation results to (b)(4) and directed (b)(4) to remind the user of the importance of maintenance, as instructed in the operation manual.

Manufacturer Narrative

On july 20, 2019, nakanishi was informed by the distributor (nam) that nam had taken the following actions as a part of the ifu recall activities.In november 2018 (exact date unknown), the distributor sent the updated operation manuals that contain the detailed reprocessing method, which had been provided by nam earlier, to the dental office to prevent the devices from overheating.On november 27, 2018, nam confirmed the receipt of the operation manuals through the activity sheet mailed by 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
• Manufacturer (Section G): NAKANISHI INC. REGISTRATION NUMBER9611253; mfr rp#:9611253-2016-00050; 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: 5938775
• MDR Text Key: 54409395
• Report Number: 9611253-2016-00050
• Device Sequence Number: 1
• Product Code: KMW
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: K171155
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: distributor,health profession
• Reporter Occupation: Dentist
• Remedial Action: Recall
• Type of Report: Initial,Followup,Followup,Followup
• Report Date: 08/15/2016,08/05/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 09/09/2016
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Dentist
• Device Model Number: SGS-E2S
• Device Catalogue Number: H266001
• Was Device Available for Evaluation?: Yes
• Is the Reporter a Health Professional?: Yes
• Was the Report Sent to FDA?: No
• Distributor Facility Aware Date: 08/10/2016
• Device Age: 1 YR
• Event Location: Other
• Date Report to Manufacturer: 08/15/2016
• Date Manufacturer Received: 07/20/2019
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 11/16/2015
• 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
• Patient Age: 16 YR