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

Model Number SGA-E2S

Device Problem Overheating of Device (1437)

Patient Problem Burn, Thermal (2530)

Event Type  Injury  

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.Nsk received a report from (b)(4) that a patient was burned on the lower lip and the dentist was also burned on the hand due to overheating of the handpiece while cutting a wisdom tooth.The event occurred 15 minutes after the treatment started.The handpiece was used in combination with surgic xt.

Manufacturer Narrative

Upon receipt of the device involved in the mdr event, nakanishi conducted a failure analysis of the returned device that included measurement of the temperature of the operating device.These activities are described in more detail below.Methodology used: nakanishi conducted rotation testing and the handpiece made abnormal noises.Nakanishi measured the temperature rise of the returned handpiece as follows.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 further toward the distal end of the device).The test setup was prepared to take temperature measurements at all points simultaneously.As a reference, nakanishi also observed a temperature rise of a brand-new sga-e2s.Nakanishi attached a thermocouple (sensor to measure a temperature) to each of the testing points ch1, ch2 and ch3.Nakanishi rotated the handpiece at 80,000rpm, which is maximum rpm for the motor that drives the handpiece (40,000 prm for the handpiece), and measured the exothermic situation.Nakanishi measured the temperature rise of the returned handpiece set at 80,000 rpm (motor revolution 40,000rpm).Nakanishi confirmed the temperature of over 70 degrees c at the test points ch1 and ch2 (points close to the patient) 15 minutes after the beginning of the measurement.The temperature of the brand-new handpiece rose to 43.6 degrees c at a maximum in the same measurement.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 debris/dirt on the bearings.Conclusions reached based on the investigation and analysis results: nakanishi identified that the cause of overheating of the returned device was due to dirt/debris ingress.A lack of maintenance causes accumulation of debris/dirt in the head, which cause dirt/debris ingress into the bearings while rotating.This will contribute to the handpiece overheating.

• 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: 4746071
• MDR Text Key: 5884723
• Report Number: 9611253-2015-00064
• 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: Company Representative,company representative
• Reporter Occupation: Service Personnel
• 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: Other
• Device Model Number: SGA-E2S
• Device Catalogue Number: H265
• Was Device Available for Evaluation?: Yes
• Date Returned to Manufacturer: 06/04/2012
• Is the Reporter a Health Professional?: No
• Initial Date Manufacturer Received: 05/31/2012
• Initial Date FDA Received: 04/30/2015
• Supplement Dates Manufacturer Received: 06/09/2018
• Supplement Dates FDA Received: 07/11/2018
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 05/31/2011
• 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