MAUDE Adverse Event Report: NAKANISHI, INC. (NSK) NSK SGA-E2S; HANDPIECE, ROTARY BONE CUTTING

Model Number SGA-E2S

Device Problem Insufficient Information (3190)

Patient Problem Burn(s) (1757)

Event Type  Injury  

Event Description

(b)(4).Event summary: on (b)(6) 2015, nakanishi received a complaint handpiece, sga-e2s, serial number (b)(4).According to the distributor, this handpiece had burned a patient.This event is under investigation.Nakanishi has requested additional information from the distributor and now is waiting for the information.However, nakanishi has started the evaluation process of the returned product.Nakanishi will submit additional information including results obtained through the investigation as a follow-up report.

Manufacturer Narrative

Upon receipt from the dentist of the device involved in the mdr event, nakanishi conducted a failure analysis of the returned device that included an attempt to measure the temperature of the operating device (c150406-02-2).These activities are described in more detail below.Methodology used: a) nakanishi examined the device history record for the subject sga-e2s device (serial number (b)(6)).There were no problems observed during the manufacturing or testing noted in the dhr.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 debris, 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 did not rotate smoothly.C) the device was configured for temperature testing in the exact state in which it was returned.Specifically, no lubrication or cleaning was performed on the returned device before this first test in order to characterize the device under conditions that would duplicate the use situation at the time of the event.D) temperature sensors were first attached to the exterior of the device at various test points (e.G., most proximal to the patient and along points farther toward the distal end of the device).The test set up was prepared to take temperature measurements at all points simultaneously.Including a reference measurement at ambient room temperature.E) nakanishi attached a thermocouple (sensor to measure a temperature) to each of the testing points.Nakanishi rotated the handpiece at (b)(4) rpm, which is maximum rpm for the motor that drives the handpiece ((b)(4) rpm for the handpiece), with water spray and measured the exothermic situation.F) nakanishi measured the temperature rise of the returned handpiece set at (b)(4) rpm (motor revolution (b)(4) rpm).Nakanishi confirmed the handpiece rotated with abnormal noise during rotation and the abnormal temperature rise on the surface of the handpiece.A) nakanishi disassembled the handpiece and performed a visual inspection of the inside parts.Nakanishi observed damage on the cartridge bearing.The amount of oil observed inside the handpiece indicated that the device was not adequately cleaned.B) due to the oil level observed, as well as the presence of some abrasive powders in the handpiece, nakanishi reassembled and washed the handpiece using nakanishi pana-spray.Nakanishl observed dirt/debris being expelled from the head of the handpiece by using a white filter to catch anything that was expelled.C) after cleaning and lubricating the handpiece as defined in the operations manual, nakanishl measured the temperature of the handpiece.Nakanishi observed that the temperatures dropped down.D) when nakanishi received the handpiece, the cartridge bearing was already damaged as discovered by the disassembly previously discussed.Therefore, the unacceptable temperature resulted even though nakanishi performed the maintenance as outlined in the operations manual (use of pane-spray).E) nakanishi then replaced the damaged bearing with a brand new bearing and measured the exothermic situation yet again.There was no abnormal temperature specifications once the damaged bearing had been replaced.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 rotational resistance, which would result in the handpiece overheating.Nakanishi reminded the user to conduct appropriate lubrication and cleaning per the user manual in order to prevent the damage to a bearing.

• Brand Name: NSK SGA-E2S
• Type of Device: HANDPIECE, ROTARY BONE CUTTING
• Manufacturer (Section D): NAKANISHI, INC. (NSK); 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• Manufacturer (Section G): NAKANISHI, INC. (NSK); 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: 4746079
• MDR Text Key: 21845350
• Report Number: 9611253-2015-00070
• Device Sequence Number: 1
• Product Code: KMW
• Combination Product (y/n): N
• Reporter Country Code: AS
• PMA/PMN Number: K970953
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Distributor
• Reporter Occupation: Service Personnel
• Remedial Action: Recall
• Type of Report: Initial
• Report Date: 07/10/2018

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 05/01/2015
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Other
• Device Model Number: SGA-E2S
• Was Device Available for Evaluation?: Yes
• Date Returned to Manufacturer: 04/08/2015
• Is the Reporter a Health Professional?: No
• Date Manufacturer Received: 06/09/2018
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 02/14/2013
• 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