7.0 mm Cannulated Screw Technique Guide

Transcription

1 7.0 mm Cannulated Screw Technique Guide An Integral Part of the SYNTHES Cannulated Screw System Original Instruments and Implants of the Association for the Study of Internal Fixation AO ASIF

2 7.0 mm Cannulated Screws Features Cannulated shaft accepts 2.0 mm diameter guide wires (threaded and non-threaded wires available). Hemispherical head ensures optimal annular contact with washers and Synthes plates when screws are angled. Standard 3.5 mm hexagonal drive is compatible with screwdrivers in other commonly used Synthes sets. Reverse-cutting flutes assist in screw removal. Choice of thread lengths offers best fit of threads into far bone fragment, for greater interfragmentary compression. Cancellous thread profile uses deep cutting threads with a large pitch to increase resistance to pullout. The large pitch also accelerates screw insertion and removal. 2.0 mm guide wire 8.0 mm diameter head with 3.5 mm hex drive Spherical underside 4.5 mm shaft diameter Reverse-cutting flutes Cancellous thread design Thread Lengths Materials 16 mm thread 32 mm thread Fully threaded Implant quality 316L stainless steel

3 Indications Intracapsular fractures of the hip Tibial plateau fractures For fracture fixation of large bones and large bone fragments, such as: Intracapsular fractures of the hip Tibial plateau fractures Femoral neck fractures Femoral intercondylar fractures Also: Sacroiliac joint disruptions Ankle arthrodeses Slipped capital femoral epiphyses Sacroiliac joint disruptions Warning: This device is not approved for screw attachment or fixation to the posterior elements (pedicles) of the cervical, thoracic or lumbar spine. 1

4 AO Principles In 1958, the AO ASIF (Association for the Study of Internal Fixation) formulated four basic principles, which have become the guidelines for internal fixation: Anatomic Reduction A guide wire marks the prescribed path for the cannulated screw and secures alignment of the fragments while the screw is being inserted. The cannulated screw is inserted over the wire and tightened to further compress the fragments and hold the reduction. Stable Fixation Cannulated screws provide interfragmentary compression and absolute stability across the fracture. The screws are available in different threads lengths, allowing the surgeon to optimize purchase in the far fragment for maximum compression and stability. Preservation of Blood Supply The use of small diameter guide wires allows precise placement of cannulated screws through small incisions. This technique minimizes disruption of soft tissue and preserves vascular blood flow for bone healing. Early Mobilization Cannulated screws, combined with AO technique, provide stable fracture fixation with minimal trauma to vascular supply. This helps to create an improved environment for bone healing, accelerating the patient s return to previous mobility and function. 2

5 Surgical Techniques Technique Tips Cleaning Cannulations Cleaning the cannulation in each instrument is imperative for proper function. Instruments should be cleared intraoperatively with the 2.0 mm Cleaning Stylet to prevent accumulation of debris in the cannulation and potential binding of the instruments about the guide wire. Instruments should be cleaned postoperatively with the stylet and the cleaning brush. Drilling Because of their hollow cross section and long length, cannulated drill bits are more susceptible to breakage than solid drill bits of the same diameter. Use less axial force, avoid bending, and advance the drill bit slowly to minimize the possibility of breakage. Cannulated drill bits should be inspected after every procedure and replaced if worn or damaged. Percutaneous insertion of screws 1 Insert guide wire Make a stab incision and insert the Percutaneous Sleeve Assembly (11.0 mm/8.0 mm Protection Sleeve, 8.0 mm/ 4.5 mm and 4.5 mm/2.0 mm Drill Sleeves, and 2.0 mm Trocar) through the soft tissue to the bone. Remove the trocar and insert a 2.0 mm Threaded Guide Wire to the appropriate depth. Confirm wire placement under image intensification. Remove all sleeves. Technique tip: To prevent slippage, the 4.5 mm/2.0 mm Drill Sleeve may be tapped with a hammer to seat the teeth in the lateral surface. Technique tip: Run the drill at maximum speed to minimize deflection while gradually advancing the guide wire. 3

6 Surgical Techniques (continued) Percutaneous insertion of screws (continued) 2 Insert additional parallel wires (if necessary) Insert one 4.5 mm/2.0 mm Drill Sleeve into the outer-most 4.5 mm hole of the parallel drill guide [319.30]. Place this combination over the previously inserted guide wire and push directly to the bone. Insert a second 4.5 mm/2.0 mm Drill Sleeve and the 2.0 mm Trocar into any of the other three holes in the parallel drill guide and press the trocar to the near cortex. Remove the trocar and insert a guide wire through the 4.5 mm/2.0 mm Drill Sleeve. Insert any additional guide wires following the same procedure and then replace. Technique tip: Avoid placing any bending forces on the first guide wire, as this will affect parallelism. Note: Any previously inserted guide wire can be used in the outermost hole of the guide for parallel placement of the next guide wire. Note: Possible distances between parallel guide wires are 10 mm, 14 mm and 18 mm, measured from the center of the primary hole of the parallel drill guide to the centers of the other holes. Plan placement of each guide wire based on these distances. 3 Measure for screw length Remove the two inner drill sleeves. Slide the tapered end of the Cannulated Screw Measuring Device over the guide wire. This reading determines appropriate screw length. Select a 7.0 mm Cannulated Screw of this length, with a thread which engages only the opposite fragment, and set it aside. Note: Screw length will be 8 mm short of the guide wire tip (the length of the threaded portion of the wire), preventing penetration of the far cortex. 4

7 4 Predrill Place the 8.0 mm/4.5 mm Drill Sleeve into the protection sleeve, and drill with the 4.5 mm Cannulated Drill Bit under image intensification to the appropriate depth, being careful not to drill over the guide wire threads and penetrate the far cortex. Remove the 8.0 mm/4.5 mm Drill Sleeve. Technique tip: Avoid directing the drill bit; let it follow the guide wire. Take care to remove the drill bit slowly and to pull back straight while running the drill forward to prevent guide wire pullout. Note: Depending on bone quality, the surgeon may choose to drill only the near cortex to prevent inadvertent guide wire pullout. Note: The calibrations on the cannulated drill bits and the cannulated tap are read at the surface of the bone and therefore can not be used when using the percutaneous sleeves. Use image intensification for confirmation of drilling and tapping depths. 5 Tap Where necessary, tap the near cortex with the cannulated tap through the protection sleeve. In dense bone, it may be necessary to tap over the entire nonthreaded length of the guide wire. 6 Insert screws Using the Cannulated Hexagonal Screwdriver without the Holding Sleeve, insert the previously selected screw (step 3) through the protection sleeve. Remove and discard the guide wire. Note: In osteopenic bone, use a washer to prevent the screw head from sinking into bone. Washers cannot be placed through the percutaneous sleeve. Remove the sleeve prior to placing the washer over the guide wire. 5

8 Surgical Techniques (continued) Open Technique 1 Insert guide wire Place a positioning guide wire in the center of the femoral neck. Place the Parallel Wire Guide [312.71] over the guide wire through one of the central diamond-patterned positioning holes. Note: The parallel guide s position may be adjusted by replacing it over the guide wire through one of the adjacent positioning holes of the central diamond pattern. Note: The parallel guide does not need to lie flush with the bone. 2 Insert additional parallel wires (if necessary) Under image intensification, insert a guide wire to the desired depth through each of the outer triangle-patterned placement holes. 3 Remove the parallel guide and the positioning guide wire (inserted in step 1). 4 Measure, drill, tap and insert each screw before proceeding to the next to prevent loss of reduction. 6

9 7.0 mm Cannulated Screw Instrument and Implant Set [105.07] Graphic Case [ ] shows step-by-step technique and provides organization for inventory control. Screw rack [ ] for 16 mm and 32 mm thread length screws is included, and replacement racks may be ordered separately. Fully threaded screws and rack are also available separately. Implants 7.0 mm Cannulated Screws, 16 mm thread length:* mm 130 mm 7.0 mm Cannulated Screws, 32 mm thread length:* mm 130 mm Also Available Washers, 13.0 mm [219.99] To prevent screw head from sinking into osteopenic bone 7.0 mm Cannulated Screws, 16 mm thread length* mm 150 mm 7.0 mm Cannulated Screws, 32 mm thread length* mm 150 mm 7.0 mm Cannulated Screws, fully threaded* mm 130 mm * 5 mm increments 7

10 Instruments 2.0 mm Threaded Guide Wire, 230 mm [292.65] Offers strength with minimal bone removal and maintains reduction during drilling. Threaded spade point tip allows easy penetration into the bone and helps prevent pullout. Black color helps differentiate it from other guide wires and K-wires of similar diameter and length. A threaded wire is also available without black color [ ], as well as a nonthreaded wire [ ]. Percutaneous Sleeve Assembly: All steps can be performed through the 11.0 mm/ 8.0 mm Protection Sleeve [319.34], including measuring and screw insertion. The 8.0 mm/4.5 mm Drill Sleeve [319.33] is used to protect soft tissue while drilling; it fits The 4.5 mm/2.0 mm Drill Sleeve [319.32] reduces the risk of guide wire deflection during surgery; it fits and The 2.0 mm Trocar [319.31] facilitates passage of the sleeve assembly through the soft tissue; it fits Note: These instruments can be used as protection sleeves for drilling and tapping during open surgery mm/8.0 mm Protection Sleeve [319.34] 8.0 mm/4.5 mm Drill Sleeve [319.33] 4.5 mm/2.0 mm Drill Sleeve [319.32] 2.0 mm Trocar [319.31] Cannulated Screw Measuring Device [319.21] Provides a direct reading of both screw length and maximum drilling depth. Blue color. 4.5 mm Cannulated Drill Bit, 233 mm, 2.1 mm cannulation, Jacobs chuck [310.69] Cannulated Tap for 7.0 mm Cannulated Screws, 150 mm calibration [311.69] Allows precise tapping in dense bone when necessary. 8

11 4.5 mm/3.2 mm Double Drill Sleeve [312.46] For protected drilling in open procedures. 4.5 mm Parallel Drill Guide [319.30] Allows parallel placement of additional guide wires for parallel screws in percutaneous or open procedures. Holding Sleeve Cannulated Hexagonal Screwdriver, 3.5 mm hex [314.19] Fully cannulated for insertion of any 7.0 mm Cannulated Screw over the guide wire. Accommodates Holding Sleeve [314.11]. 2.0 mm Drill Bit, 100 mm, quick coupling [310.19] For predrilling for the guide wire. 2.0 mm Cleaning Stylet [319.36] For cleaning cannulated instrumentation. 2.1 mm Cleaning Brush [319.27] For postoperative cleaning of 7.0 mm Cannulated Screw instruments. Parallel Wire Guide [312.71] For parallel placement of screws during open fixation of femoral neck fractures. Screw Forceps [319.97] Note: Instruments should be cleared intraoperatively with the 2.0 mm Cleaning Stylet to prevent accumulation of debris in the cannulation and potential binding of the instruments about the guide wire. Instruments should be cleaned postoperatively with the stylet and the cleaning brush.

12 Set Contents 7.0 mm Cannulated Screw Instrument and Implant Set [105.07] Implants 7.0 mm Cannulated Screws, 16 mm thread length* mm 65 mm, 2 ea. 70 mm 100 mm, 4 ea. 105 mm 130 mm, 2 ea. 7.0 mm Cannulated Screws, 32 mm thread length* mm 105 mm, 2 ea. 110 mm 130 mm, 1 ea Washer, 13.0 mm, 6 ea. Instruments mm Threaded Guide Wire, 230 mm, 10 ea mm Drill Bit, 100 mm, quick coupling, 2 ea mm Cannulated Drill Bit, 233 mm, Jacobs chuck, 2 ea Cannulated Tap for 7.0 mm Cannulated Screws mm/3.2 mm Double Drill Sleeve Parallel Wire Guide Holding Sleeve Cannulated Hexagonal Screwdriver Cannulated Screw Measuring Device mm Cleaning Brush mm Parallel Drill Guide mm Trocar, 118 mm, 2 ea mm/2.0 mm Drill Sleeve, 108 mm, 2 ea mm/4.5 mm Drill Sleeve, 99 mm mm/8.0 mm Protection Sleeve, 88 mm mm Cleaning Stylet Screw Forceps 7.0 mm Cannulated Screw Instrument and Implant Set Graphic Case Also Available mm Cannulated Screws, 16 mm thread length, 135 mm 150 mm, 5 mm increments mm Cannulated Screws, 32 mm thread length, 135 mm 150 mm, 5 mm increments mm Cannulated Screws, fully threaded, 20 mm 130 mm, 5 mm increments mm Threaded Guide Wire, spade point both ends, 230 mm mm Non-Colored Threaded Guide Wire, spade point, 230 mm mm Non-Threaded Guide Wire, spade point one end, 230 mm, blue Cannulated Countersink, for 7.0 mm Cannulated Screws Cannulated 3.5 mm Hexagonal Screwdriver Shaft, for 7.0 mm Cannulated Screws Large Hexagonal Screwdriver, for removal of 7.0 mm Cannulated Screws Screw Rack for 7.0 mm Cannulated Screws, fully threaded Small Battery Drive with 14.4 V Battery Pack Sets: H with Hudson Reduction Drive Unit M with Modified Trinkle Reduction Drive Unit T with Trinkle Reduction Drive Unit Power Drive Set * 5 mm increments SYNTHES (USA) 1690 Russell Road Paoli, PA Telephone: (610) Fax: (610) To Order: (800) SYNTHES (CANADA) LTD Meadowpine Boulevard Mississauga, Ontario L5N 6P9 Telephone: (905) Fax: (905) To Order: (800) SYNTHES (USA) SYNTHES and ASIF are registered trademarks of SYNTHES (USA) and SYNTHES AG Chur. Printed in U.S.A. GP1191-C 6/04 J2425-C