Abstract Septoplasty is a common nasal surgery that corrects a deviated septum. To correct the deformity, the mucous membrane must be separated from the septum. Once the deformities have been corrected, the mucous membrane must be reattached to the septum tightly. This is accomplished by inserting a purse-string suture. The suturing process is somewhat lengthy when performed manually, taking approximately 15 to 30 minutes. With operating room costs at about $60 per minute, the suturing time is quite costly. Our goal is to develop a device to reduce the time it takes to place the suture. Our design concept is a magnetic needle passer composed of two electromagnetic coils that alternate current to attract the needle to either one. This semester we focused on demonstrating a needle pass between two magnets and quantifying the force the magnetic field will have to generate to efficiently pull the needle from the septum.

Background: Nose Nostril: flexible chamber  10-15mm wide Septum: elastic quadrangular cartilage divides the nose into two nostrils  3-5mm wide Deviated septum: misalignment of the septum from the midline  Corrected with Septoplasty

Background: Septoplasty Incision made to expose caudal end of septum Cartilage excised and/or reshaped to realign Mucous membrane is reattached with absorbable nylon suture in a purse-string pattern

Design Constraints Size  The tip of the device must fit within the confines of the nose which is about 10 to 15 mm on either side of the septum. The needle is limited by the width of the septum(3-5mm). Force  Magnetic coils must generate a field great enough to pull needle out of the septum With N force

Performance  Reduce the suturing time to 10 min  Can not fail or malfunction during the procedure  Mimic the current suturing procedure Patient Safety  Must either be one-time use or autoclavable  It must be sterile upon use to reduce incidence of infection  No increased chance of misplacing the needle during suturing Cost  If the device is one-time use, it should cost no more than $300.  If it is for multiple use, it should cost no more than $1500.

Force Testing Cantilever beam strain gage Calibrated with known weights Salt pork used to simulate septal cartilage Ham steak and chicken breast also tested

Average Maximum Force for Salt Pork= lb (0.645 N) sd=0.024 lb

Conceptual Prototype Magnetic field generated by coils secures needle Switch controls magnetic field activation Arms are mechanically closed

Electromagnet Current through coil of wire Magnetic field strength limited by current and number of turns per length Magnetic field increases with smaller radius

160 turns per unit length (the whole spool) 22 AWG wire 4 Amps 0.098N

Materials and Costs MaterialAmountCost ($) Coil25.00 Iron bolt23.00 Switch12.00 Power Supply Total50.00

Future Work Build to scale  0.07mm diameter double ended needle  1 cm wide Build magnet at sufficient force  Permanent magnet  Reverse polarity Plastic casing with clamping mechanism Test on human cartilage

Special Thanks Professor Tyler Dr. Marcus Amit Nimunkar

References Autosuture. 29 January Azom. 6 March Chao, et al. Dynamic changes in the elastc modulus of nasal septal cartilage. Proc. SPIE vol4257. Cool Magnet. 20 April Cornell. 27 February Fact Sheet. 2 March Homicz, et al. A Compositional Analysis of Human Nasal Septal Cartilage. Arch Facial Plastic surgery. 2003: 5: Kortenbach, Juergen Andrew. “Automatic needle-passer suturing instrument.” Patent no. 5,814, Lore, John. An Atlas of Head and Neck Surgery. 1988:Philadelphia. Modern Plastics. 6 March Septoplasty. 27 February Septum. 7 March 2007.