Electro Magnetic Needle Passer for Nasal Surgery Advisor Professor Mitch Tyler Department of Biomedical Engineering Client Dr Benjamin Marcus Department of Otololaryngology Mark Yarmarkovich Team Leader Joseph Cabelka Communicator Jennifer Wager BSAC Therese Rollmann BWIG 05 9 07 Table of Contents Abstract 3 Background Project Motivation 3 Nasal Features 4 Septoplasty Procedure 4 Sutures 8 Current Device 10 Design Constraints 12 Materials 14 Alternate Designs Design I Mechanical Needle Passer 15 Design II Mechanical Clamp 17 Design III Magnetic Needle Passer 18 Design Matrix 20 Force Testing 21 Electro Magnet Prototype 24 Materials and Costs 26 Future Work 27 Ethics 28 References 30 Appendix A PDS 32 Appendix B Magnetic Force Calculations 36 Appendix C Force Testing Data 39 2 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 tightly to the septum 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 final design concept is an electro magnetic needle passer that passes a double ended needle between two magnetic coils The needle is mechanically driven into the septum with a clamping device and held in place with a magnetic field As the jaws open up the needle is fully extracted from the septum and this process is repeated until the suture is complete This term was spent proving our concept of a magnetic needle passer with an up scaled prototype and quantifying the force required to pull the needle from the septum which was 0 145 lb Background Project Motivation The goal of this project to is develop a device to reduce the suturing time during nasal surgery Septoplasty is a common nasal surgery that corrects a deviation in the septum which is the cartilage in the center of the nose During a septoplasty the lining surrounding the septum is removed to expose the septum and correct the deformity Once the cartilage is reshaped sutures are used to reattach the lining to the septum The suturing process can take the surgeon 15 to 30 minutes With operating room costs being 3 about 60 per minute the suturing procedure alone can cost 900 to 1800 The development of an auto suture device would reduce the suturing time and operating room costs The surgeon would also free up more time that could be spent on treating more patients Nasal Features The nose is the protuberance that houses the nostrils required for airflow The septum is the elastic quadrangular cartilage barrier that divides the nose into two chambers It is approximately 3 to 5 mm wide and is surrounded by a mucous membrane The elastic modulus of cartilage is approximately 10 MPa but the properties of the septum can vary from person to person with one having a thick and stiff septum and another having a thin and brittle septum The nostrils that are on either side of the septum are approximately 10 to 15 mm wide and are very flexible When there are obstructions of the nasal passageways due to a birth defect or trauma corrective surgery is often required 4 6 8 11 14 Septum 3 5mm Nostril Mucous lining Fig 1 Shown above is a diagram of the nose Septoplasty Procedure The septum is seen in the middle dividing the nose into two chambers On either side of the septum is a nostril 4 A misalignment of the nose from the midline known as a deviated septum Figure 2 often causes difficulty in breathing and sleeping The deviated septum leaves a disproportionate opening in the nostrils leaving one larger than the other The smaller nostril experiences an impaired flow of air Though it may seem that the larger nostril would receive a greater flow of air the opposite is actually true The mucous of the larger nostril often becomes dried out often leaving the larger nostril with less air flow than the smaller nostril A deviation of the septum can be treated with a procedure known as a septoplasty An initial incision is made along the base of the nose to expose the caudal end of the septum as shown in Figure 3 The surgeon must then decide which portions of the cartilage must be cut and which must be removed to allow the nose to be straightened Figure 4 The reason that the cartilage must be removed is to prevent the overriding of the cartilage onto itself in the straightening of the nose A right angle knife is used to excise the selected sections of the cartilage Figure 5 and the septum is then swung into alignment Since cartilage is known to have a position memory a Teflon splint is often used to secure the cartilage into alignment to prevent the septum from redeviating Figure 6 The initial incision is then sutured in a purse string suture pattern using nylon absorbable sutures 10 11 5 Figure 2 Shown above is how a deviated septum may appear on a patient Figure 3 An initial incision is made along the base of the nose to expose the caudal end of the septum 6 Figure 4 A portion of the cartilage is removed or shaped to straighten the appearance of the nose The labels on the cartilage are used for surgical purposes Figure 5 A right angle knife is used to excise selected sections of cartilage 7 Figure 6 A Teflon splint can be used to secure the septum into alignment and prevent it from re deviating Sutures Suturing is the surgical method in which polymer fibers are used to join two surfaces Similar to sewing suturing is performed with a thread and needle The needle is typically made of an alloy The thread can be manufactured to serve many different purposes depending on their use Sutures must be strong enough to effectively hold together the joined tissue They must be non toxic and hypoallergenic to reduce the body s reaction to the material Additionally they must be flexible to withstand movement of the tissues Suture types are categorized according to the type of material they are made of the permanence of the material sutures that the body eventually absorbs or non absorbable sutures that need to be removed at a later date and their construction braided twisted monofilament For septoplasty the sutures used are typically nylon absorbable and braided 6 16 8 Figure 7 A diagram of a braided suture is shown
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