technique guide - alfamed plusthe proper atraumatic technique enables minimal retraction or...

Synapse System. An enhanced set ofinstruments and implants forposterior stabilization of the cervical andupper thoracic spine.

Technique Guide

Introduction

Surgical Technique

Product Information

Assembly Guide

Synapse System 2

AO Principles 4

Indications and Contraindications 5

Preparation 6

Surgical Technique 8

Additional Techniques 20

Implants 26

Instruments 28

Screwdriver Assembly 32

Rod Introduction Instrument Assembly (03.614.027) 34

Drill Sleeve Assembly (388.393) 35

Depth Gauge Assembly (03.161.028) 36

Image intensifier control

WarningThis description alone does not provide sufficient background for direct use of the product. Instruction by a surgeon experienced in handling this product is highlyrecommended.

Table of Contents

Synthes 1

50° 50°

Synapse System. An enhanced set ofinstruments and implants forposterior stabilization of the cervical andupper thoracic spine.

2 Synthes Synapse System Technique Guide

The Synapse System is an enhanced set of instruments andimplants, including clamps, top-loading variable axis screws,hooks, transverse connectors and transverse bars and rods,designed for posterior stabilization of the cervical and upperthoracic spine. The implants provide the flexibility required toaccommodate variations in patient anatomy.

The Synapse System uses 3.5 mm rods, allowing componentsfrom Synapse, Axon, CerviFix/StarLock and Occipito-CervicalFusion System to be interchanged. This allows a construct toextend from the occiput to the lower spine using the Occip-ito-Cervical Fusion System and the Universal Spine System(USS).

System features– 3.5 mm titanium* rods– Top-loading hooks– Square-threaded locking screws– Robust polyaxial screws– Simple, efficient instrumentation– Multiple implant options for crossing the cervicothoracic

junction– Fully compatible with the Occipito-Cervical Fusion system

Robust polyaxial screws– Three diameters with cancellous profile– Shaft screws with cortical profile– 50° maximum screw angulation

* Titanium-6% aluminium-7% niobium alloy

Medial, 50 mm width Medial, 60 mm width

Lateral, 50 mm width Lateral, 60 mm width

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Synapse is fully compatible with the Occipito-CervicalFusion system for posterior occipito-cervical fixationsThe Synthes Occipito-Cervical Fusion System is intended toprovide stabilization and promote fusion of the occipito-cer-vical junction. It includes a complete set of implants and in-struments designed to optimize fixation to the occiput andeasily connect with all Synthes posterior cervical and thoracicrod-screw systems.

Versatile fixation possibilities to the occiputThe Occipito-Cervical Fusion System offers several implantoptions to maximize fixation to the occiput and minimize theimplant footprint.

For further information see Technique Guide “Occipito- Cervical Fusion System“ (036.000.755).

Occipital plates


AO Principles

In 1958, the AO formulated four basic principles, which have become the guidelines for internal fixation.1 They are:

– Anatomical alignment– Stable internal fixation– Preservation of blood supply– Early, active mobilization

The fundamental aims of fracture treatment in the limbs andfusion of the spine are the same. A specific goal in the spineis returning as much function as possible to the injured neu-ral elements.2

AO Principles as Applied to the Spine 3

Anatomical alignmentIn the spine, this means reestablishing and maintaining thenatural curvature and the protective function of the spine. Byregaining this natural anatomy, the biomechanics of thespine can be improved, and a reduction of pain can be expe-rienced.

Stable internal fixationIn the spine, the goal of internal fixation is to maintain notonly the integrity of a mobile segment, but also to maintainthe balance and the physiologic three-dimensional form ofthe spine.3 A stable spinal segment allows bony fusion at thejunction of the lamina and pedicle.

1 Müller ME, Allgöwer M, Schneider R, Willenegger H (1995) Manual of InternalFixation. 3rd, exp. a. completely rev. ed. 1991. Corr. 3rd printing. Berlin,Heidelberg, New York: Springer

2 Ibid.3 Aebi M, Arlet V, Webb JK (2007) AOSPINE Manual (2 vols), Stuttgart, New York:

Thieme

Preservation of blood supplyThe proper atraumatic technique enables minimal retractionor disturbance of the nerve roots and dura, and maintainsthe stability of the facet joints. The ideal surgical techniqueand implant design minimize damage to anatomical struc-tures, i.e. facet capsules and soft tissue attachments remainintact, and create a physiological environment that facilitateshealing.

Early, active mobilizationThe ability to restore normal spinal anatomy may permit theimmediate reduction of pain, resulting in a more active,functional patient. The reduction in pain and improved func-tion can result when a stable spine is achieved.

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Indications and Contraindications

The Synapse System is an enhanced set of instruments andimplants, including– top-loading variable axis screws,– hooks,– transverse bars and– rods.

It is designed for posterior stabilization of the cervical spineand upper thoracic spine. The implants provide the flexibilityrequired to accommodate variations in patient anatomy.

IndicationsInstabilities in the upper cervical spine and in theoccipitocervical region:– Rheumatoid arthritis– Congenital anomalies– Posttraumatic conditions– Tumors– Infections

Instabilities in the lower cervical and upper thoracic spine:– Posttraumatic conditions– Tumors– Iatrogenic instabilities following laminectomy etc.

Degenerative and painful posttraumatic conditions in thelower cervical and upper thoracic spine

Anterior cervical fusions requiring additional posterior stabilisation

Contraindications– Spinal destruction accompanied by a loss of ventral sup-

port (caused by tumors, fractures and infections) results inmajor instability of the cervical spine and upper thoracicspine. In this situation, stabilization with Synapse is notsufficient. Additional anterior stabilization is crucial.

– Severe osteoporosis

Preparation


1Preparation

Required set

01.614.012 Synapse System in Vario Case

68.614.012 Vario Case for Synapse Instrumentsor68.614.014 Vario Case for Synapse Instruments:

Axon Upgrade

68.614.016 Vario Case for Synapse Implantscontaining:

68.614.018 Module for Synapse Screws� 3.5/4.0 mm and Shaft Screws

68.614.019 Module for Synapse Screws � 4.5 mm68.614.020 Module for Synapse Rods and

Locking Screws68.614.021 Module for Synapse Hooks

2Preoperative planning

All necessary imaging studies should be available to planimplant placement and visualize individual patient anatomy.

3Position the patient

Patient positioning is critical for cervical posterior fusion pro-cedures. The patient should be placed on the operating tablein the prone position with the patient’s head securely immo-bilized. Proper patient position should be confirmed via directvisualization prior to draping and by radiograph.

Always use caution when positioning the patient, as physio-logic alignment may not be attainable.

4Approach

Use the standard surgical approach to expose the spinousprocesses and laminae of the vertebrae to be fused.

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5Assemble instruments

The following instruments have to be assembled prior to use:– Screwdriver– Rod introduction instrument– Drill sleeve– Depth gauge

Assemble instrument parts according to the Assembly Guideon page 32 following.


Surgical Technique

1Start screw hole

Instrument

388.397 Awl � 3.5 mm

Determine the entry point and trajectory for the screw anduse the awl to create a pilot hole. This helps to prevent dis-placement of the drill bit during initial insertion.

2Select screw and drill sleeve

Instrument

388.393 Drill Sleeve with Scale, for Drill Bitor � 2.4 mm03.614.011 Drill Sleeve with Scale, for Drill Bit

� 3.2 mm

Select the drill bit and drill sleeve that correspond to thescrew diameter to be used. 3.5 mm and 4.0 mm screws havethe same core diameter (2.4 mm) and are to be used withthe same drill bit and drill sleeve, identified with a yellowband. 4.5 mm screws have a larger core diameter (3.2 mm)and are to be used with the drill bit and drill sleeve identifiedwith a light blue color band. See table below.

ScrewDiameter 3.5 mm 4.0 mm 4.5 mm

Drill Bit 388.394 388.394 03.614.010

Drill Sleeve 388.393 388.393 03.614.011

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3Set drill sleeve depth

Instrument

388.393 Drill Sleeve with Scale, for Drill Bitor � 2.4 mm03.614.011 Drill Sleeve with Scale, for Drill Bit

� 3.2 mm

To set the drill sleeve to the desired depth, slide back thelatch to release the inner tube; align the distal end of the in-ternal drill sleeve tube with the appropriate depth calibrationon the window. Release the latch to lock the drill sleeve atthe desired depth.

Surgical Technique


4Drill hole

Instruments

388.393 Drill Sleeve with Scale, for Drill Bit� 2.4 mm

388.394 Drill Bit � 2.4 mm with Stop

388.549 Feeler, straight, with rounded tip

Drill to the desired trajectory and depth, using the 2.4 mmdrill bit and drill sleeve. Use the feeler to confirm, by palpa-tion, accurate placement within the pedicle or lateral mass.

Note: Perform drilling in steps until the appropriate depth isreached.

Alternative instruments

03.614.010 Drill Bit � 3.2 mm with Stop

03.614.011 Drill Sleeve with Scale, for Drill Bit� 3.2 mm

Alternative technique

Instruments

03.614.012 Pedicle Probe � 2.4 mm, straight03.614.013 Pedicle Probe � 2.4 mm, curvedor03.614.037 Pedicle Probe � 3.2 mm, straight03.614.038 Pedicle Probe � 3.2 mm, curved

Pedicle preparation may also be performed using either thestraight or curved pedicle probe.

Note: Radiographically confirm position and orientation ofthe drill hole.

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Optional technique

Instruments

389.473 Pedicle Marker, small, with short markings

389.474 Pedicle Marker, small, with long markings

The small pedicle markers may be used to radiographicallyconfirm position and orientation of screw sites.

5Measure

Instrument

03.161.028 Depth Gauge

Use the depth gauge to confirm hole depth and select thecorresponding screw length. The depth gauge reading andthe screw length indicate actual bone purchase. The depthgauge must sit directly on the bone.


6Insert screw

Instruments

03.614.017 Holding Sleeve with thread

03.614.036 Outer Sleeve for Holding SleeveNo. 03.614.017

03.614.039 Hexagonal Screwdriver Shaft, cross pinned

324.107 Handle with Quick Coupling

Refer to page 32 for screwdriver assembly and implant at-tachment instructions.

Insert the selected 3.5 mm or 4.5 mm self-tapping Synapsescrew. A 4.0 mm emergency screw may be used if the pri-mary 3.5 mm screw has less than optimal fixation.

Note: The outer sleeve should be used to grip the holdingsleeve during screw insertion.

Surgical Technique

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Instruments

03.614.015 Tap for Cancellous Bone Screws � 4.5 mm

03.614.016 Guide Sleeve for Tap � 3.5 mm and� 4.5 mm

311.349 Tap for Cancellous Bone Screw � 3.5 mm

389.477 Tap for Cortex Screw � 3.5 mm

Dense bone may be tapped using the appropriate tap, depending on the chosen screw.

The guide sleeve may be used as a tissue protector, and toindicate tap depth.


7Place additional screws

Use the same technique to insert the remaining screws.

8Contour template

Instrument

388.868 Trial Rod � 3.5 mm

Contour the rod template to fit the anatomy.

Surgical Technique

Synthes 15

Internalledge

Alternative bending technique

Instruments

03.614.024 Bending Iron, left

03.614.025 Bending Iron, right

The bending irons can also be used as pipe rod benders. Insert the rod into the rear of each bending iron and lock inplace by turning the thumbwheels clockwise. With bothends locked inside the irons, the rod may be contoured.

Note: Repeated bending may weaken the rod.

9Bend and cut rod

Instruments

03.614.021 Cutting Pliers for Rods

03.614.022 Bending Pliers

Use the bending pliers to contour the rod to match the curveof the template. The bend line arrow indicates where the rodwill be bent.

Use the cutting pliers to cut the rod to the appropriatelength.

Alternative techniqueShorter rod sections may be bent by placing one end of therod on the internal ledge of the bending feature.


10Insert rod

Instrument

388.407 Holding Forceps

Optional instruments

03.614.024 Bending Iron, left

03.614.025 Bending Iron, right

03.614.034 Alignment Tool

Insert the rod into the variable axis heads of the screws usingthe holding forceps. The alignment tool may be used to helporient the heads to the correct position. The bending ironsmay be used to adjust the curve of the rod.

11Insert locking screw

Instruments

03.614.019 Screwdriver Shaft Stardrive forLocking Screw, T15

03.614.035 Handle with Torque Limiter, 2.0 Nm

Loosely fasten the locking screws using the screwdriver shaftwith the 2 Nm torque limiting handle. When inserting thelocking screws, they may be turned one-quarter to one-halfturn counterclockwise to seat the thread before tightening.

Surgical Technique

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Instrument

03.614.027 Rod Introduction Instrument

Use the rod introduction instrument to introduce the 3.5 mmtitanium rod into the variable axis head of the screw. Placethe instrument over the rod and onto the variable axis headuntil the tip of the instrument sits below the screw head re-duction feature. Squeeze the handle to engage the instru-ment and introduce the rod into the head of the screw.Loosely fasten the locking screws using the screwdriver shaftwith the 2 Nm torque limiting handle through the cannula-tion of the rod introduction instrument. When inserting thelocking screws, they may be turned one-quarter to one-halfturn counterclockwise to seat the thread before tightening.


12Lock construct

Instruments

03.614.019 Screwdriver Shaft, Stardrive forLocking Screw, T15

03.614.026 Rod Pusher

03.614.035 Handle with Torque Limiter, 2.0 Nm

After final adjustment of the construct, fully tighten all lock-ing screws with the screwdriver shaft and the 2 Nm torquelimiting handle. The construct is now rigidly locked. Finaltightening should be accomplished after all locking screwshave been placed, and should be aided by the rod pusher.

Note: The rod pusher may be used in place of the rod introduction instrument to lock the construct.

Surgical Technique

Optional technique

Instrument

03.614.023 Holding Forceps for Rods � 3.5 mm

If rotation of the rod is desired, it is recommended that theholding forceps be used.

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13Apply compression or distraction

Instruments

03.614.028 Distraction Forceps

03.614.029 Compression Forceps

Compression or distraction with variable axis heads is onlypossible if the locking screws have not been tightened. Usethe compression forceps to achieve compression, or the dis-traction forceps to achieve distraction, and then tighten thelocking screw as described in step 12.


Additional Techniques

Adding rod to rod transverse connectors

Instruments




388.038 Crimper for Transverse Connectors

388.407 Holding Forceps

a. Position the transverse connectorsPlace the transverse connectors on the Synapse rod con-struct. The transverse connectors may be held with the hold-ing forceps.

Place top loading hooks

Instruments


03.614.030 Holding Forceps for Implants


a. Position hookAttach the holding forceps to the appropriate hook. Placethe hook in the desired location using the screwdriver as anaid.

b. Insert rod

c. Insert locking screwTighten the locking screw using the screwdriver shaft forlocking screw. Turn the screwdriver one-quarter to one-halfturn counterclockwise to seat the thread before tightening.

Synthes 21

b. Tighten clampTighten the setscrew of the transverse connector hook onthe rod with the screwdriver shaft. Slide the rod within thehook if necessary. Hold the second hook in the appropriateposition and tighten the setscrew.

Tip: The 3.5 mm rod may be bent to accommodate theanatomy. Locking one end of the transverse connector withthe crimper may facilitate placement.

c. Lock connectionsLock both bushing connections with the crimper. Ensure thatthe golden tip of the instrument is facing medially whenlocking the connection. The transverse connector is nowrigidly locked.

Note: If necessary, the connection can be unlocked using thesame instrument with the golden tip facing laterally. The rodmay be shortened with the cutting pliers.


Adding transverse bars

Instruments



Place the opening of the 3.5 mm titanium transverse barover the 3.5 mm rod. Loosely attach the transverse bar tothe rod. Introduce the transverse bar into the variable axishead of the screw. Insert the locking screw in the variableaxis head as described in steps 11 and 12. Tighten thesetscrew of the transverse bar using the screwdriver shaft.

Occipital Fusion TechniqueOccipital plates or occipital clamps may be attached to theocciput as described in the Technique Guide for the Occipito-Cervical Fusion System (036.000.755). These plates orclamps can then be connected to the Synapse system via 3.5 mm rods or pre-bent rods.

Additional Techniques

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Parallel ConnectorsAll parallel connectors are open and allow side-loading ofthe rods. They link � 3.5 mm to � 3.5 mm, 5.0 mm and6.0 mm rods. Either side of the connector may be connectedfirst. Tighten the setscrew on one side, then connect theremaining rod and tighten the setscrews.

Implant Removal

Instruments


03.614.039 Hexagonal Screwdriver Shaft, cross pinned


All Synapse system implants can be removed with a T15Stardrive screwdriver. The transverse connectors also requirethat the crimper be used for removal.

Note: Synapse polyaxial screws may also be removed withthe cross pinned hexagonal screwdriver shaft.

Tapered RodsTapered rods may be used to extend a Synapse construct.Connect the 3.5 mm section to the Synapse polyaxial screwsas instructed in steps 8 –12 of the surgical technique.Connect the 5.0 mm/6.0 mm end of the rod to theappropriate Universal Spine System (USS).

50° 50°

50° 50°

40° 40°

40° 40°

� 4.0 mm

� 3.5 mm � 4.5 mm

� 3.5 mm shaft screw


Implants

Variable axis screws

Cancellous screws– 3.5 mm and 4.0 mm cancellous screws offer up

to 50° of angulation in all directions– 4.5 mm cancellous screws offer 40° of angula-

tion in all directions– Self-tapping– Thread length from 8 mm to 50 mm– Square thread locking cap reduces occurrence

of cross-threading– 8.0 mm run on rod

Outer Diameter Core Diameter Color Code(mm) (mm)

3.5 2.4 Gold

4.0 2.4 Green gray

4.5 3.2 Light blue

Shaft screws– Offer 40° of angulation in all directions– 3.5 mm cortex self-tapping screws– Lengths from 18 mm to 50 mm* with a 10 mm

unthreaded shaft

Other implants

Lamina hooks– For sublaminar insertion and stabilization– Short/long offsets ease construct assembly– Top-loading hooks– Straight hooks– Side-loading hooks

* Screw length is total length.

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Transverse connectors– Preassembled transverse connectors are available in

lengths of 60 mm and 75 mm– Easily placed after Synapse construct is in

position, reducing operative time– Bushings allow clamps to be placed offset to each other– Assembly can be rigidly locked

3.5 mm rods– 3.5 mm rods are available in lengths of 80 mm, 120 mm

and 240 mm– 3.5 mm curved rods are available in lengths of 40 mm

and 80 mm

Tapered rods– Rods with dual diameters of 3.5 mm/5.0 mm and

3.5 mm/6.0 mm in 120 mm/175 mm length– 5 mm transition zone allows adjacent screws to be

placed closer together– Link the Synapse system to the Universal Spinal System

(USS)

Transverse bars– Provide a lateral offset of up to 9 mm from the 3.5 mm

rod to the Synapse screw– Eliminate the need for severe rod contouring– Can be placed onto the rod from the top after the Synapse

construct is in position– 5.0 mm and 6.0 mm clamps facilitate connection between

the Synapse system and thoracolumbar system

Parallel Open Rod Connectors– The 3.5 mm/5.0 mm and 3.5 mm/6.0 mm parallel open

rod connectors link the Synapse construct to the UniversalSpinal System (USS)

– The 3.5 mm/3.5 mm parallel open rod connector providesa lateral offset to assist in crossing the cervicothoracic junction


03.161.028 Depth Gauge for Screws � 3.5 to 5.0 mm,measuring range to 50 mm

03.614.010 Drill Bit � 3.2 mm with Stop, length245/69 mm, 2-flute, for Quick Coupling

03.614.011 Drill Sleeve with Scale, for Drill Bits � 3.2 mm No. 03.614.010

03.614.012 Pedicle Probe � 2.4 mm, straight

03.614.013 Pedicle Probe � 2.4 mm, curved

292.745 Kirschner Wire � 2.4 mm with Stop, length 170 mm

Instruments

Synthes 27

03.614.016 Guide Sleeve for Tap � 3.5 mm and � 4.5 mm


03.614.019 Screwdriver Shaft Stardrive for LockingScrew, T15, for Quick Coupling


03.614.015 Tap for Cancellous Bone Screws� 4.5 mm, length 245 mm, for Quick Coupling


03.614.022 Bending Pliers for Rods � 3.5 mm andPlates 3.5 mm

03.614.023 Holding Forceps for Rods � 3.5 mm

03.614.024 Bending Iron, leftand03.614.025 Bending Iron, right

03.614.026 Rod Pusher

03.614.027 Rod Introduction Instrument

Instruments

Synthes 29

03.614.028 Distraction Forceps

03.614.029 Compression Forceps

03.614.030 Holding Forceps for Implants

03.614.034 Alignment Tool

03.614.035 Handle with Torque Limiter, 2.0 Nm, withQuick Coupling

03.614.036 Outer Sleeve for Holding Sleeve No. 03.614.017


311.349 Tap for Cancellous Bone Screw � 3.5 mm,length 185/46 mm, for Quick Coupling



388.393 Drill Sleeve with Scale, for Drill Bit � 2.4 mm No. 388.394

388.394 Drill Bit � 2.4 mm with Stop, length171/65 mm, 2-flute, for Quick Coupling

03.614.039 Hexagonal Screwdriver Shaft, cross pinned,for Quick Coupling

Instruments

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389.477 Tap for Cortex Screw � 3.5mm, length185 mm, for Quick Coupling

388.407 Holding Forceps for Rods � 3.5 mm,length 181 mm

388.549 Feeler, straight, with rounded tip

388.868 Trial Rod � 3.5 mm

Pedicle Markers, small389.473 with short markings389.474 with long markings

388.397 Awl � 3.5 mm, length 179.5 mm


Figure 1

Button

“Speedbump”

Greencolorband

Outersleeve

Screwdriver Assembly

Instruments


03.614.039 Hexagonal Screwdriver Shaft,cross pinned


Optional instruments

03.614.036 Outer Sleeve for Holding SleeveNo. 03.614.017

– Add the outer sleeve to the holding sleeve. Insert the hold-ing sleeve through the slotted end of the outer sleeve pastthe threads of the holding sleeve. Snap the outer sleeveover the “speed bump.” (1)

– Insert the back end of the cross pinned hexagonal screw-driver shaft through the distal tip of the holding sleeve (2).Press the button on the holding sleeve while inserting thescrewdriver shaft. Ensure that the holding sleeve has bot-tomed out on the cross pin at the distal end of the screw-driver shaft.

– Connect the handle with quick coupling to the hexagonalscrewdriver shaft (3).

– Reset the driver by pressing the button on the sleeve andpulling back on the sleeve until it hits the handle (4). Thegreen color band on the sleeve should not be visible.

Driver is ready for use.

Figure 2 Figure 3 Figure 4

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Attach screwdriver to polyaxial screw– Ensure that the driver is in the reset position. The green

color band on the holding sleeve should not be visible.

– Insert the tip of the hexagonal screwdriver shaft into thebone screw of the polyaxial screw (5).

– Slide the sleeve until it comes in contact with the body ofthe polyaxial screw (6).

– Rotate the sleeve clockwise until it bottoms out on thecross pin of the hexagonal screwdriver shaft (7). The greencolor band should be visible. The polyaxial screw is readyfor bone insertion.

Remove screwdriver from the polyaxial screw– Rotate the sleeve counterclockwise. Before accepting an-

other polyaxial screw the driver should be reset as shownin figure 4. The green color band on the holding sleeveshould not be visible.

Figure 5 Figure 6 Figure 7

1

2

3

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2


Rod Introduction InstrumentAssembly

(03.614.027)

1

1

2

2

Synthes 35

Drill Sleeve Assembly (388.393)


Depth Gauge Assembly (03.161.028)

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technique guide - alfamed plusthe proper atraumatic technique enables minimal retraction or...

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