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

Model Number SGS-E2S

Device Problems Overheating of Device (1437); Temperature Problem (3022)

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

Event Date 11/26/2014

Event Type  Injury  

Manufacturer Narrative

Upon receiving the device involved in the mdr event from a distributor, nakanishi conducted a failure analysis of the returned device that included measuring the operating temperature of the device [c141201-10-1].These activities are described in more detail below.Methodology used: a) nakanishi examined the device history record and the repair history for the subject sgs-e2g device [serial (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.B) nakanishi conducted a visual inspection of the returned device and performed a simple movement test.There were no visible abnormalities, such as cracks or dents, on the outside of the handpiece.Nakanishi then set a test bur in the handpiece and rotated it by hand.Nakanishi observed that the bur rotated smoothly.C) nakanishi conducted temperature testing of the returned device in the following manner: c.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.C.2) nakanishi attached a thermocouple (sensor to measure a 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 (80,000 min-1 for the handpiece), without water spray, and measured the exothermic response.C.3) nakanishi measured the temperature rise of the returned handpiece set at 80,000 min-1 (motor revolution 40,000 min-1).Nakanishi observed an abnormal temperature rise at test point (1), (2) and (4) a few seconds after the start.Temperature measurements 150 seconds after the start are as follows: - test point (1): 67.6 degrees c - test point (2): 67.3 degrees c - test point (3): 50.7 degrees c - test point (4): 60.0 degrees c the rise in temperature was so sudden that the test was concluded 150 seconds into the planned 5 minute evaluation period.D) nakanishi cleaned the inside of the handpiece using nakanishi pana spray plus.Nakanishi did not observe debris being expelled from the head of the handpiece by using a white filter to catch anything that was expelled.E) after cleaning and lubricating the handpiece as defined in the operation manual, nakanishi measured the temperature of the handpiece for the entire 5-minute evaluation period.There was no abnormal rise in temperature during the 300-second-test period (see below).- test point (1): 49.2 degrees c - test point (2): 47.7 degrees c - test point (3): 38.6 degrees c - test point (4): 39.7 degrees c f) again, nakanishi cleaned the inside of the handpiece and measured the temperature as described in d) and e).Nakanishi observed further decrease in temperature, as follows.- test point (1): 35.0 degrees c - test point (2): 35.5 degrees c - test point (3): 35.4 degrees c - test point (4): 37.2 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 debris on the inside parts, especially on the bearings.B) nakanishi took photographs of all of the disassembled parts and kept them in the investigation report #c141201-10-1.Conclusions reached based on the investigation and analysis results: 1) nakanishi identified that the cause of the overheating of the returned device was abnormal resistance during rotation caused by the soiled bearings due to the ingress of undesirable materials into the bearings.2) a lack of maintenance causes the accumulation of debris on the inside parts, which causes debris ingress into the bearings during rotation.This 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 clarity and understandability of the instructions.3.2) 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.

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 information that we can obtain from the initial complainant.On november 28, 2014, nakanishi received an e-mail from a distributor ((b)(4)) about a handpiece overheating.Details are as follows.The event occurred on (b)(6) 2014.An oral surgeon was performing a temporomandibular joint surgery on a patient using the handpiece, sgs-es (serial (b)(4)).The handpiece burned the patient's lip.

• 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.; 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: 7281194
• MDR Text Key: 100410707
• Report Number: 9611253-2018-00006
• Device Sequence Number: 1
• Product Code: KMW
• Combination Product (y/n): N
• Reporter Country Code: SN
• PMA/PMN Number: K970953
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: distributor,foreign
• 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

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Dentist
• Device Model Number: SGS-E2S
• Device Catalogue Number: H266
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 12/09/2014
• Is the Reporter a Health Professional?: No
• Was the Report Sent to FDA?: No
• Initial Date Manufacturer Received: 11/28/2014
• Initial Date FDA Received: 02/19/2018
• Supplement Dates Manufacturer Received: 06/09/2018
• Supplement Dates FDA Received: 07/12/2018
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 01/29/2014
• 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: 32 YR