Surgical Technique and Ordering Information
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Table of contents Description... 4 Indications for use... 4 Contraindications... 4 State-of-the-art design features... 5 Surgical Technique... 6 Surgery Steps (Example: Headless screw)... 7 Troubleshooting... 10 Explantation... 11 Ordering information... 12 Screws... 12 Instruments... 14 3
Description Description The Mecron Cannulated Screw System consists of headed and headless bone screws (Fig. 1) made from titanium alloy. Screws are available in diameters from 2.0 mm through 4.0 mm and overall lengths from 8 mm through 50 mm (Tab. 1). Available Screw Dimensions Headed and Headless screws are color-coded according to diameter. Srew Diameter Color Length 2.0 White 8-50 mm 2.5 Magenta 10-50 mm 3.0 Blue 10-50 mm 3.5 Green 10-50 mm 4.0 Gold 10-50 mm Table 1 Available Screw Dimensions. Figure 1 Headed (left) and headless (right) screws. Shown: Ø 4.0 mm (yellow). XX Indications for use The Mecron Cannulated Screw System is indicated for use in bone reconstruction, osteotomy, arthrodesis, joint fusion, ligament fixation, fracture repair and fracture fixation appropriate for the size of the device. XX Contraindications Osteoarthritis Primary chronic polyarthritis Osteoporotic bone. 4
Description XX State-of-the-art design features Headed Screw With a smooth curvature to prevent soft tissue interferences under oblique insertion angles that lead to proud heads along cortical bone. The selected head geometry keeps the screw from plunging into softer bone. A reinforced neck encounters stress at a traditional weak point. Headless Screw Furnished with a tapered neck to prevent cracks in cortical bone while controlled pre-compression is achieved before the proximal thread engages. The thread design securly anchors the head in cortical bone through heightened teeth while the first and last pitch have self-tapping cutting flutes to facilitate insertion and removal. The thread design along the shaft is optimized through an ideal pitch differential to the head. This keeps distal threads from stripping through premature compression. Also, an enlarged bone interface area is achieved in combination with increased pullout resistance. The cannulated screws provide strengths that outperform industry standards and competitors. Hexalobe Driver Driver connections are self-clamping for hexalobe driver sizes of T8, T10 and T20. Selt-tapping and self-drilling threads Each tip has three cutting flutes for self-drilling and selftapping properties to reduce insertion torques during surgery. 5
Description Surgical Technique Mecron Cannulated Screws are self-tapping and self-drilling and may simply be inserted over a K-wire with the included hexalobe driver. However, in dense cortical bone, this may be difficult. Therefore, the following surgery steps (illustrated for Ø 4.0 mm screws) include bone preparation with overdrill, drill and countersink. All instrument are color-coded according to the corresponding screw diameter (Tab. 2) to provide optimal ease of use. All instruments are color-coded Instrumentation according to Screw Diameter Screw Diameter (in mm) Color Double Drill Guide (in mm) Drill (in mm) Overdrill (in mm) Countersink (in mm) Headed Headless Hexalobe Driver K-wire (in mm) 2.0 White 1.8 1.8 1.7 2.0 4.0 3.2 T8 Star 0.9 2.5 Magenta 1.8 2.6 1.7 2.5 4.0 3.2 T8 Star 0.9 3.0 Blue 2.2 3.1 2.1 3.0 5.0 3.5 T10 Star 1.1 3.5 Green 2.6 3.6 2.5 3.5 5.0 3.5 T10 Star 1.1 4.0 Gold 2.6 4.1 2.5 4.0 6.0 4.0 T10 Star 1.2 Table 2 Instrumentation according to screw diameter, with part number and colors for corresponding screws 6
Surgical Technique XX Surgery Steps (Example: Headless screw) Position the K-wire (e.g. Ref. CK12215) across the fracture or fusion site (Fig. 2). Confirm accurate K-wire placement and appropriate depth under fluoroscopy. Figure 2 fracture or fusion site K-wire insertion. Position across Slide the universal length gauge (Ref. AI14002) over the K-wire (Fig. 3). The measurement on the length gauge shows the depth of the K-wire in the bone and indicates the appropriate screw length. Figure 3 Screw length determination for headed or headless compression screws a) b) Place a double drill guide (Tab. 2) over the K-wire. The cannulated overdrill (Tab. 2) is placed over the guide wire (Fig. 4a) and through the drill guide to produce a pilot hole up to the fracture or fusion site (Fig. 4b). Use the drill to advance the pilot hole to the distal cortex. The drill bit may be used as a measuring device for screw length determination. The screw length is equivalent to the drill depth illustrated through markings on the shaft. Figure 4 Pilot hole prepared with drill and overdrill. Overdrill advanced to fusion site (a.) followed by the drill until the distal cortex is reached (b.). 7
Surgical Technique Use the cannulated countersink (e.g. Ref. CH15034, Tab. 2) to create a recess for the screw head (Fig. 5). Note! Headed screws, especially if inserted under an oblique angle, should be countersunk prior to screw lengths determination (Fig. 6a). Headless screws are generally countersunk after the screw length is determined (Fig. 6b.). Figure 5 Countersinking for headed or oblique compression screws Surgery Steps for Headed Screws a) 1 2 3 4 5 6 Step 1) K-wire placement. Step 2) Overdrill Step 3) Drill Step 4) Countersink Step 5) Universal Length Gauge Step 6) Driver for Screw Insertion Surgery Steps for Headless Screws b) 1 2 3 4 5 6 Step 1) K-wire Placement. Step 2) Universal Length Gauge Step 3) Overdrill Step 4) Drill Step 5) Countersink Step 6) Driver for Screw Insertion Figure 6 Surgery Steps. Countersinking performed prior to length determination for headed or oblique screws (a) or vice versa for headless screws (b). 8
Surgical Technique Load the required cannulated hexalob driver (Tab. 2) into the ratcheting handle (Ref. FH90003) (Fig. 7). Figure 7 Loading screwdriver. Ratcheting handle (Ref. FH90003) loaded with hexalobe driver. Insert the predetermined Mecron Cannulated Screw with the loaded screwdriver. Advance the screw until the head is flush with the periosteum and the fusion site is sufficiently compressed (Fig. 8a). Confirm placement and length of the screw under fluoroscopy, ensuring that both leading and trailing edges of the screw are placed beneath the cortex. Finally, remove the K-wire (Fig. 8b). a) b) Figure 8 Screw insertion. Drive in the selected screw (a) and remove the K-wire (b). 9
Surgical Technique XX Troubleshooting Occasionally, soft bone (e.g. cancellous bone) allows the head of the inserted screw to plunge onward while the distal end of the screw advances inwards (Fig. 9). Plunging headless screws (Symptom A) may be substituted with headed screws for a secure cortical fixation (Solution A). Plunging headed screws (Symptom B) can be secured with washers (Solution B) selected for the corresponding screw diameter (Tab. 3). a) Symptom A Solution A b) Symptom B Solution B Color code for washers 2.0 2.5 3.0 3.5 4.0 Figure 9 Washer Installation. Plunging of headless screws through cortical bone (a.) is prevented through the installation of a headed screw or the use of washers (b.) Table 3 Washer selection. Colors of each matching washer. Distal threads sometimes displace cancellous bone while the head remains in cortical bone. This may be prevented by selecting a larger screw size (Fig. 10). Symptom C Solution C Figure 10 Stripping of distal thread prevented through the selection of a longer screw or the redirection of a new screw of the same length. 10
Surgical Technique XX Explantation Generally, explantation procedures are left to the discretion of the surgeon. However, the following steps may be necessary to recover deformed or fractured screws. Remove the proximal, damaged fragment of the screw with the appropriate hexalobe driver (Tab. 2) if the hexalobe connection remains intact (Fig. 11). Figure 11 Recovery with hexalobe driver. A functioning connection within the head of the screw allows recovery with a hexalobe driver. Insert the screw extractor (Ref. CH15017) with its trocar tip in the cannulation of the remaining screw fragment until it is firmly seated (Fig. 12). Drive the trocar tip into the cannulation of the screw. Note! The screw extractor may be applied immediately if the driver connection of the screw is damaged. Figure 12 Recovery with the screw extractor. Insert trocar tip until the screw extractor is firmly seated in the remaining screw fragment. Attach the T-Handle (Ref. AI90100) to the AO quick connector of the screw extractor. The damaged screw is removed by carefully turning the T-handle counterclockwise while applying constant axial pressure (Fig 13). Figure 13 Recovery with the screw extractor. T-Handle connected and turned counterclockwise. 11
Ordering information Ordering information XX Screws Order example Screw DIA 4,0 mm, full thread 32 mm, non-sterile Requied Ref. CH40332T Mecron Cannulated Screws, headed, non-sterile Description Screw Color Ref DIA 2.0 mm, short thread 8-50 mm (2 mm increments) CH20108T - CH20150T DIA 2.0 mm, full thread 8-50 mm (2 mm increments) CH20208T - CH20250T DIA 2.5 mm, short thread 10-50 mm (2 mm increments) CH25110T - CH25150T DIA 2.5 mm, full thread 10-50 mm (2 mm increments) CH25210T - CH25250T DIA 3.0 mm, short thread 10-50 mm (2 mm increments) CH30110T - CH30150T DIA 3.0 mm, full thread 10-50 mm (2 mm increments) CH30210T - CH30250T DIA 3.5 mm, short thread 10-50 mm (2 mm increments) CH35110T - CH35150T DIA 3.5 mm, full thread 10-50 mm (2 mm increments) CH35210T - CH35250T DIA 4.0 mm, short thread 10-50 mm (2 mm increments) CH40110T - CH40150T DIA 4.0 mm, long thread 10-50 mm (2 mm increments) CH40210T - CH40250T DIA 4.0 mm, full thread 10-50 mm (2 mm increments) CH40310T - CH40350T Mecron Cannulated Screw, headless, non-sterile Description DIA 2.0 mm, short thread 8-50 mm (2 mm increments) DIA 2.5 mm, short thread 10-50 mm (2 mm increments) DIA 3.0 mm, short thread 10-50 mm (2 mm increments) DIA 3.5 mm, short thread 10-50 mm (2 mm increments) DIA 4.0 mm, short thread 10-50 mm (2 mm increments) DIA 4.0 mm, long thread 10-50 mm (2 mm increments) Screw Color Ref CH21108T - CH21150T CH26110T - CH26150T CH31110T - CH31150T CH36110T - CH36150T CH41110T - CH41150T CH41210T - CH41250T 12
Ordering information Screw Diameter Washer Ref 2.0 CH15044 2.5 CH15045 3.0 CH15046 3.5 CH15047 4.0 CH15048 13
Ordering information XX Instruments Instrument inset Left for implantation Ref. Description Oty. FH90003 Ratcheting Handle 1 CH15016 Countersink with Length Gauge 4215-SS Retractor 1 4685 Clamp, small 1 1 Instrument inset, Right, for explantation Ref. Description Oty. AI90100 T-Handle 1 CH15017 Screw Extractor 1 AI14332 Driver T8 Star 1 AI14333 Driver T10 Star 1 14
Ordering information DIA. 2.0 mm Caddy Ref. Description Oty. CH15002 Drill 2 CH15009 Overdrill 2 CH15023 Countersink - Headed 2 CH15030 Countersink - Headless 2 CK09115 K-wires 0.9 x 150 mm 8 CH15037 Tissue Protector 1 AI14335 Driver T8 Star 1 AI14001 Length Gauge 1 gs 86.6108 Forceps 1 DIA. 3.5 mm Caddy Ref. Description Oty. CH15005 Drill 2 CH15012 Overdrill 2 CH15026 Countersink - Headed 2 CH15033 Countersink - Headless 2 CK11115 K-wires 1.1 x 150 mm 8 CH15040 Tissue Protector 1 AI14336 Driver T10 Star 1 AI14001 Length Gauge 1 gs 86.6110 Forceps 1 DIA. 2.5 mm Caddy Ref. Description Oty. CH15003 Drill 2 CH15010 Overdrill 2 CH15024 Countersink - Headed 2 CH15031 Countersink - Headless 2 CK09115 K-wires 0.9 x 150 mm 8 CH15038 Tissue Protector 1 AI14335 Driver T8 Star 1 AI14001 Length Gauge 1 gs 86.6108 Forceps 1 DIA. 4.0 mm Caddy Ref. Description Oty. CH15006 Drill 2 CH15013 Overdrill 2 CH15027 Countersink - Headed 2 CH15034 Countersink - Headless 2 CK12215 K-wires 1.2 x 150 mm 8 CH15041 Tissue Protector 1 AI14336 Driver T10 Star 1 AI14001 Length Gauge 1 gs 86.6110 Forceps 1 DIA. 3.0 mm Caddy Ref. Description Oty. CH15004 Drill 2 CH15011 Overdrill 2 CH15025 Countersink - Headed 2 CH15032 Countersink - Headless 2 CK11115 K-wires 1.1 x 150 mm 8 CH15039 Tissue Protector 1 AI14336 Driver T10 Star 1 AI14001 Length Gauge 1 gs 86.6108 Forceps 1 Figure 14 Examplary Screw Caddy for DIA. 4.0 mm screws, with all diameter specific instruments in a subjacent drawer. 15
Distributor U.S.: One Lincoln Centre 18W140 Butterfield Road, 15th Floor Oakbrook Terrace, IL 60181 HDB0128-0617 Phone: 630-613-7181 Customer Service Tel: 630-613-7182 Fax: 630-613-7184 E-Mail: service@merete-medical.com www.merete-medical.com