i. Implantsii. Systems1. Surgical material2. Surgical approach (Femur)3. Application4. Osteotomy 5. Finishing

RatDisSurgical technique guide

External fixation SystemStabilization of the Femur with an external distractor. Continous in-vivo bi-directional adjustment of the gap size is possible.

Technology The RatDis system is a locked external distrac-tor made of PEEK, TAN and 316L which offeres a simple and an adjustable design.We currently offer two standard models, one for the femur and another for the mandible.The RatDis Mounting pin is made of TAN and comes in one standard length with a four flange drive enabling application and removal of the pin.Distraction is possible in 0.25 mm (half turn) increments.

i

assembled RatDis Femur, available as left & right version, pitch 0.50 mm / full turn

assembled RatDis Mandible, available as left & right version, pitch 0.50 mm / full turn

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The RatDis available can be used within the femur and the mandible. The images on the right demonstrate the various models of RatDis applied to the rat.

ii. Systems

RatDis mounted on Femur

RatDis mounted on Mandible

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Implants:- 1x RatDis Femur - 4x RatExFix Mounting pins 0.85 mm

1. Surgical material

Instruments:- 2x hand drills - 1x Accu Pen 6V+

Consumables:- 1x 0.79 mm Drill bit - 1x 1.00 mm CenteringBit - 1x Square box wrench 0.70 mm - 1x Slot Drive Bit 0.50 mm- 1x 0.44 mm Gigly wire saw, 0.50 m- 1x Vicryl suture 3-0 - Skin glue (Epiglue) / Vicryl suture 5-0 - 1x Ethibond Vicryl suture 6-0

RIS.593.203 Drill Bit 0.79 mm

RIS.632.211 RatDis Femur RIS.412.100 RatExFix Mounting pin 0.85 mm

RIS.390.130 Hand drill

RIS.590.112 Square box wrench 0.70 mm

RIS.390.211 AccuPen 6V+

RIS.590.110 Gigly wire saw 0.44 mm

RIS.592.205 Centering Bit 1.00 mm

RIS.590.113 Slot Drive Bit 0.50 mm

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PositioningRat in prone position.

2. Surgical approach (femur)

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Approach Longitudinal skin incision along the femur from the hip joint to the knee.

2. Surgical approach

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2. Surgical approach Small medial incision of the fascia lata and blunt preparation of the muscle below.

M. vastus lateralis and M. biceps femoris are split and M. tensor fasciae latae is lifted to expose the full length of the femur preserv-ing the sciatic nerve.

Circular preparation of the femur at the area of the planed osteotomy.

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Application of the Gigli wire sawPut the wire saw closely around the bone in medio-lateral orientation.

3. Application

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Orientation of the RatDis Position the RatDis according to the illustra-tion on the right side. Make sure that the distraction rod (1) is on top and towards yourself.Before mounting the RatDis ensure the correct setup (distance L) of the MainBodies (2). If neccessary adjust the distance by turning the distraction rod (1), one turn = 0.50 mm.

Centering of the first screw hole Position the device on the prepared femur in anterolateral direction by externally rotating the femur.After correct positioning carefully create the countersink with the centering bit 1.0 mm.

3. Application

12 2

L

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Preparation for drilling and screwingBy applying the first Mounting pin the alignment of the distractor is determined. Therefore it is important to pay attention to positioning the distractor parallel to the femur.

Adjust the orientation of the longitudinal axis so that the distractor is aligned anterolat-erally and parallel to the bone.

Retain rotation of the bone until you have inserted the first Mounting pin.

3. Application

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3. ApplicationDrilling and insertion of the Mounting pinInsert the drill bit into the distal hole (1) of the distractor and check the position of the drill bit (tip pointing into the countersink). While drilling make sure that you drill completely through both cortices.

Place the MountingPin into the distal hole (1) of the distractor (remember the upside down orientation of the bar). Turn the MountingPin into the distractor until the upper thread is flush with the top surface of the MainBody.

While screwing the MountingPin with the distractor into the bone make sure to exactly follow the predrilled hole. Stop turning when the end of the lower thread is close to the top surface of the bone.

1

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3. ApplicationSequence of screw placementDrill the hole for the second screw (2) proximal to the planned osteotomy and insert the screw.

The third (3) and the last screw (4) should be placed in the order shown in the illustration.

1 4 23

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4. Osteotomy / Distraction

Accomplishing the osteotomyCreate an osteotomy in the middle of the two inner MountingPins (sufficient irrigation).

Start sawing by keeping your hands close to-gether. With progressing saw depth increase hand distance to avoid high forces.

DistractionFrom now on it is possible to adjust the osteotomy gap according to the applied study design.

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5. FinishingWound closure

The fascia lata is closed with vicryl suture 3-0.

Skin suture with Polyamid suture 3-0.

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Hazards and legal restrictionsScientific editor: Katharina Schmidt-Bleek, Germany Agnes Ellinghaus, GermanyIllustrations: Sandra Wissing, SwitzerlandDesign and layout: Romano Matthys, Switzerland In collaboration with: Julius Wolff Institut and Center for Musculoskeletal Surgery Charité-Universitätsmedizin Berlin, GermanyHazards Great care has been taken to maintain the accuracy of the information contained in this publication. However, the publisher, and/or the distributor, and/or the editors, and/or the authors cannot be held responsible for errors or any consequences arising from the use of the information contained in this publication. Contributions published under the name of individual authors are state-ments and opinions solely of said authors and not of the publisher, and/or the distribu-tor, and/or the RISystem Group. The products, procedures, and therapies described in this work are hazardous and are therefore only to be applied by certified and trained medical professionals in environments specially designed for such procedures.

RISystem AGTalstrasse 2A7270 DavosSwitzerlandinfo@risystem.comwww.risystem.com

No suggested test or procedure should be carried out unless, in the user‘s professional judgment, its risk is justified. Whoever applies products, procedures, and therapies shown or described in this work will do this at their own risk. Because of rapid advances in the medical sciences, RISystem recommends that independent verification of diagnosis, therapies, drugs, dosages, and operation methods should be made before any action is taken. Although all advertising material which may be inserted into the work is expected to conform to ethical (medical) standards, inclusion in this publication does not constitute a guarantee or endorsement by the publisher regarding quality or value of such product or of the claims made of it by its manufacturer.

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