how to inject the cervical and thoracolumbar articulations · how to inject the cervical and...

How to Inject the Cervical and ThoracolumbarArticulations

Mark J. Martinelli, DVM, PhD, Diplomate ACVS*; Lea A. Walker, DVM;Norman W. Rantanen, DVM, MS, Diplomate ACVR; andBarrie D. Grant, DVM, MS, Diplomate ACVS

Authors’ address: California Equine Orthopedics, PO Box 788, San Marcos, CA 92079; e-mail:[email protected]. *Corresponding and presenting author. © 2012 AAEP.

1. Introduction

Topline issues are common among all disciplines inequine practice.1–3 These problems can be dividedup by anatomical location and generally involve thecervical, thoracolumbar, and sacroiliac regions.Treatment of the former two by injection will becovered in this report.

The cervical spine should be considered the con-duit for all signals traveling from the control centerof the brain to the rest of the body, particularly allfour limbs.4 In the horse, issues associated withthe neck may be related to its gravitationally chal-lenged anatomical construct, functioning as a hori-zontally positioned boney column supported by theelastic nuchal ligament. During exercise, particu-larly in disciplines that require the horse to assumea collected cervical frame, excess stress may beplaced on these articulations, either between thecervical bodies or the facet joints.5

Cervical dysfunction in people is commonly re-ported in orthopedic practice and is often associatedwith weakness and pain in the appendages or localpain restricting movement.6,7 Most often the clin-ical signs are described verbally to the attendingphysician; the gold standard for imaging of cervical

lesions in the human patient is MRI. Due to thelimitations of magnet design, however, it is not cur-rently and may never be feasible to image the caudalcervical region of the horse. Therefore, equine cli-nicians are limited in their imaging capacity to ra-diology, ultrasound, and nuclear scintigraphy. Incases in which compression is suspected, myelogra-phy enhances the radiographic study but must beconducted under general anesthesia.

In our opinion, any horse with mild ataxia, inter-mittent or unrelenting forelimb lameness, or ob-scure hind limb lameness should be investigated forcervical issues.8,9 The pathophysiology associatedwith an obscure lameness may be due to a proprio-ceptive deficit, nerve root compression, or pain.Proprioceptive deficits may be described by thetrainer or rider simply as “being heavy on the fore-hand” or feeling “disjointed” between the fore andhind limbs. Furthermore, any time a generalizeddecrease in performance is noted without corre-sponding lameness, a problem affecting any part ofthe axial skeleton should be ruled out. Recurrenceof appendicular lameness after successful treatmentmay also be indicative of an underlying problemwith the axial skeleton. In our practice, the most

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HOW TO MAKE RATIONAL CHOICES FOR INTRA-ARTICULAR INJECTIONS

NOTES

Orig. Op. OPERATOR: Session PROOF: PE’s: AA’s: 4/Color Figure(s) ARTNO:

1st disk, 2nd beb spencers 9 3,5-8,11,12,15,17 3350

common clinical signs associated with pathology inthe thoracolumbar region are localized pain andaversion to saddling or mounting. More severelyaffected horses will react to the weight of the rider,sometimes violently, by bucking or rearing.

The physical examination of the entire axial skel-eton of the horse is subjective and may be consideredlimited compared with examination of the limbs.Assessment of the neck includes observation of mus-cular development or atrophy, the response to pas-sive cervical manipulation, and dermal stimulation.In many cases of cervical arthropathy, muscularatrophy is noted. Most horses that exhibit abnor-mal cervical manipulation either resist lateral flex-ion totally or avoid lateral flexion by offering a moreventral flexion of the head and neck. The rideroften describes resistance to lateral bending, being“heavy on one rein” or resistance to achieving theframe desired. In some cases, particularly with up-per-level dressage horses, the avoidance of this de-sired frame can even result in hypertrophy of theaffected muscles along the topline. Examination ofthe thoracolumbar region can be even more subjec-tive, with a painful response to direct pressure vari-able among horses.

It can be difficult to rule out problems in the axialskeleton without the screening tool of nuclear scin-tigraphy (Fig. 1), as these areas are easily high-lighted by increased radiopharmaceutical uptake(IRU). In the case of myelopathy, no IRU may benoted in the cervical region. Radiography alonecan be used to document some cases of cervical ar-thropathy. Radiography can highlight enlargedfacets (Fig. 2), previous trauma (such as fracture),or entheseous bone formation and narrowing ofthe spinal canal, although these findings may notalways carry clinical significance. Findings onultrasound may include periarticular osteophytosis/entheseophytosis not seen radiographically. Ultra-

sound is also used to identify the facet joint and toguide the needle for proper intra-articular therapy.

The treatment of issues associated with the axialskeleton can often be challenging. In many cases,injection of the affected area with anti-inflammatorymedication (corticosteroids) or autologous condi-tioned seruma (ACS) may be indicated. Injectiontechniques for the cervical and thoracolumbar re-gions are described below.

2. Materials and Methods

Cervical Facet InjectionCervical facet injection is performed once the jointsto be treated are identified and the appropriate anti-inflammatory medication is selected. This tech-nique has been described by many authors and hasevolved over the years.10–14 The following proce-dure is described for the standing, sedated horse.

The materials needed for the procedure includethe following:

● A new bottle of local anesthetic solution● One 12-mL syringe (for the local anesthetic)

Fig. 1. Nuclear scintigraphy shows significant IRU and enlarge-ment associated with C6-C7.

Fig. 2. A and B, Radiograph of the base of the cervical regionshows significant enlargement and osteophytosis at C6-C7(above) compared with the more normal appearance of C6-C7(below).

468 2012 � Vol. 58 � AAEP PROCEEDINGS


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● Several 25-gauge, 11⁄2-inch hypodermic nee-dles (for deposition of local anesthetic)

● The anti-inflammatory of choice (new bottle ifusing corticosteroids)

● 18-gauge 31⁄2-inch spinal needles (for facetjoint injection)

● Multiple 3-mL syringes (for the anti-inflam-matory agent), one for each facet joint to beinjected

● Amikacinb (if desired, particularly if usingcorticosteroids)

● Alcohol in a standard spray bottle● Sterile scrub (chlorhexidine or betadine)

Ultrasound of the Articular FacetsBefore performing the procedure, it is necessary toensure adequate ultrasound penetration, using onlyalcohol without the use of any coupling gel (Fig. 3).In our clinic, ultrasound is performed using a mul-tifrequency linear probe with the frequency set ateither 8 or 10 MHz. Well-muscled horses may bemore difficult to scan at the base of the neck, butlower-frequency settings and increased gain willusually allow for adequate penetration. If the im-age quality is insufficient, particularly during thefall and winter months, it may be necessary to clipthe hair. We initially use a No. 10 blade, but insome cases clipping with a No. 40 blade is needed tovisualize the facet joints adequately.

Anatomic knowledge of the cervical vertebrae andtheir articular processes is imperative to successfulultrasound identification of the facet joints. Thecervical spine follows the ventral line of the neck,and the location of each articulation can be esti-

mated by using the general rule that each cervicalvertebra is approximately one hand-width. Thevertebrae can be counted starting at the base of theear moving toward the shoulder, with the spacesbetween each hand serving as the estimation of eachvertebral articulation. Once the approximate loca-tions of the joint(s) of interest have been identifiedfrom cranial to caudal using the hand-width rule,the location of the joint from dorsal to ventral mustalso be determined. The best way to do this is toidentify the level of the transverse processes of theassociated cervical vertebrae. The articular facetsare usually located 6 to 8 cm proximal to the line ofthe transverse processes. Once the approximate lo-cation has been identified from cranial to caudal anddorsal to ventral, the ultrasound probe is placedperpendicular to the ventral line of the neck. Theprobe should initially be placed in a more ventralposition at the level of the articular facet of interestand moved proximally until the joint is identified(Fig. 4). As the probe is advanced dorsally towardthe facet joint, it is often helpful to sweep craniallyand caudally with the ultrasound probe to ensurethat it is located in the middle of the facet joint.Difficulty can arise when there is significant pathol-ogy resulting in periarticular osteophytes, as thiswill sometimes obscure visualization of the jointspace. Again, sweeping cranially and caudally willusually help identify a more congruent articularmargin. Typically, the facet joint at C6-C7 sits di-rectly in front of the line of the shoulder created bythe supraspinatus muscle.

5. Preparation for Articular Facet InjectionThe horse is usually sedated with an alpha-2 agonistsuch as detomidinec or romifidine,d combined withbutorphanole if necessary. The dose is at the dis-cretion of the veterinarian and should be aimed at

Fig. 3. After alcohol is sprayed over the cervical region, the facetjoints to be injected are located with the ultrasound.

Fig. 4. The ultrasonographic appearance of the facet joint atC6-C7 (arrow).



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providing adequate sedation so the horse will notmove or attempt to raise its head during the injec-tion, but without becoming so sedate that the horseis swaying or buckling at the knees. It should benoted that if the horse seems overly sedated or be-comes significantly ataxic with a small dose of analpha-2 agonist, cord compression may be present.This should be taken into consideration, particularlyif treatment of the articular facet joints does notresult in resolution of the presenting clinical signs.The neck should be prepared with an initial scrub ofa chlorhexidine or betadine solution (Fig. 5). Alco-hol is then sprayed over the area to be examinedultrasonographically. When placing the ultra-sound probe on the neck, it is critical to know whichside of the screen is dorsal and which side of thescreen is ventral because this will determine theside of the screen the needle will be entering from.Whether the needle always advances from the sameside of the screen or another method is used (i.e.,needle comes in from the left side of the screen onthe left side of the neck and from the right on theright side), it should be done the same way for everyhorse to ensure consistency. To facilitate injection,the articular margin of the facet joint should belocated toward the lower half of the screen to allowfor adequate needle visualization. The needle willbe placed approximately 1 cm dorsal to the proximaledge of the ultrasound probe (Fig. 6). The injectionsite is first blocked with 2 to 4 mL of local anestheticusing a 25-gauge needle. A subcutaneous bleb isplaced initially, and then the needle may be ad-vanced to deposit some anesthetic intramuscularly(Figs. 7 and 8). This is especially important wheninjecting sensitive horses. Once the skin over thefacet joints to be injected has been desensitized, asterile preparation of the injection site is performedwith a chlorhexidine or betadine scrub solution.

Articular Facet InjectionThe facet joints are again identified with ultrasoundand the 18-gauge, 31⁄2-inch needle is insertedthrough the skin bleb, approximately 1 cm dorsal tothe proximal edge of the ultrasound probe (Fig. 9).Once through the skin, the needle is slowly ad-vanced axially and ventrally at approximately a 45-degree angle (Fig. 10). The needle should beadvanced slowly, ensuring that it can be visualizedon the ultrasound screen. If the needle is not visi-ble, the operator should sweep the ultrasound probefrom cranial to caudal until the needle is visualized.Adjustments in the angle while the needle is beingadvanced should be done as early as possible in theprocess because this becomes more difficult, the

Fig. 5. The ventral aspect of the cervical region is scrubbedbefore blocking and then again before injecting. We prefer chlo-rhexidine scrub, particularly in gray horses, because betadinetends to stain the hair.

Fig. 6. Once the facet joint is located ultrasonographically, localanesthetic is injected just dorsal to the probe with a 25-gaugeneedle.

Fig. 7. The local anesthetic is placed as a bleb under the skinand then somewhat deeper into the muscle, especially on moresensitive horses. In this case, the bleb for C5-C6 is being placed;the bleb for C6-C7 can be seen in the background.



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deeper the needle penetrates within the muscle.This is particularly important when injecting C6/C7or in heavily muscled horses in general. In addi-tion, multiple needle tracks in the muscle may cre-ate air artifacts, making visualization more difficultover time. The needle should be advanced axiallyand ventrally, following the progress on the ultra-sound screen as it approaches the articular margin,until the bone is contacted at the tip of the needle(Fig. 11). The stylet is removed from the spinalneedle, and the medication of choice is injected.An assistant can remove the stylet and inject themedication, allowing the operator to continue watch-ing the process on the ultrasound screen (Fig. 12).

If no assistant is available, then the operator musthold the needle steady once in the proper positionand put the probe down so he or she can inject themedication. If there is resistance to injection, itmay be beneficial to rotate the needle a quarter-turnor retract the needle a very small amount (1 mm)because it may be up against the bone or cartilage,creating difficulty on injection. If at any time bloodis seen at the hub of the spinal needle, the needleshould be removed and the injection started over.Synovial fluid is seen inconsistently, and it is notnecessary to obtain fluid to ensure intra-articularinjection, provided the ultrasonographer is confidentwith the needle placement.

Fig. 8. Local anesthetic being injected over C5-C6 and C6-C7. Inshow horses, the long mane can be braided to keep it clear of thesites to be injected.

Fig. 9. Once the area is scrubbed again and sprayed with alco-hol, the facet joint is located with the ultrasound and an 18-gaugespinal needle is introduced at a 45-degree angle just dorsal to theprobe.

Fig. 10. The needle can be seen approaching the facet joint(arrow).

Fig. 11. The needle is placed at the level of the facet joint, readyfor injection.



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Postinjection Protocol: Cervical Facet JointsFollow-up treatment with a systemic anti-inflam-matory can be done at the discretion of the attendingveterinarian. The exercise protocol varies, depend-ing on the severity of the cervical arthrosis andwhether it is a first-time treatment. For more se-verely affected horses, particularly those beingtreated for the first time, we recommend a verycareful return to athletics. The horse is hand-walked for several days, followed by a return to lightwork under saddle. Trotting and cantering is rein-troduced slowly, with no attempt at collection orexcessive cervical bending initially. By 3 to 4weeks after injection, full work is allowed, includingasking for a frame. In cases of repeat injection, thereturn to full work and collection is much quickerand may occur within 2 to 5 days.

Thoracolumbar Facet Injections

Injection TechniqueA technique has been described for an ultrasound-guided injection of the thoracolumbar intervertebralfacet joints.15 Preparation is similar to the cervicalspine; however, the injection site is not desensitizedbefore injection, and a longer needle is recom-mended. Identification of the facet joints begins byfinding the 18th rib and following it dorsally to itsarticulation at T17-T18. The probe is held just offmidline and angled slightly axially, initially findingthe dorsal spinous process (DSP), which can be fol-lowed down to the facet joint (Fig. 13). The facetjoint is identified as a transverse hyperechoic lineproximal to the rib (thoracic) or transverse process(lumbar) (Fig. 14). The needle can be placed eitheraxial or abaxial to the ultrasound probe. In theaxial approach, the needle is positioned parallel tothe DSP and perpendicular to the skin, whereas in

the abaxial approach, the needle should be angled atapproximately 40 degrees before insertion.

Thoracolumbar DSP Injections

Injection TechniqueIn cases when over-riding DSPs are creating clinicalsigns, it may be advantageous to inject anti-inflam-matory medication adjacent to the over-riding pro-cesses.16 In most cases, the offending region isidentified either by nuclear scintigraphy or radiog-raphy. Counting cranially (or caudally) from the18th rib, each DSP is identified. The injection tech-nique used involves placing the ultrasound probedirectly on midline to identify the DSPs (Fig. 15).Once the offending space is located, the probe ispositioned so that the caudal edge of cranial DSPand the cranial edge of the caudal DSP is visualized,placing the space between the two directly in the

Fig. 12. If an assistant is available (left), they remove the styletand inject the medication while the ultrasonographer steadies theneedle and continues to view the screen, ensuring that the med-ication is deposited into the joint space.

Fig. 13. The ultrasound probe is in place for location and injec-tion of a thoracic facet joint.

Fig. 14. The thoracolumbar facet joints have often been de-scribed as looking like a “chair.”



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center of the screen (Fig. 16). After routine prepa-ration, a 25-gauge, 11⁄2-inch needle is introduceddirectly abaxial to the probe and angled back towardmidline until the bone is contacted (Fig. 17). Noattempt is made to inject “between” the DSPs be-cause most cases associated with clinical signs havelittle space between over-riding processes. Thisprocedure is repeated on both the left and right sidesof midline.

Postinjection Protocol: DSPsThe return to work after injection of the spacesbetween the DSPs is usually immediate but does notgenerally involve any under-saddle exercise ini-tially. It is usually beneficial to begin by line-driv-

ing or lunging aimed at stretching and rounding thetopline. Depending on the severity of the over-rid-ing DSPs, the return to full work under saddle maybe several days to several months. In the case ofyoung, immature horses, it may even be beneficial toturn the horse out for 6 to 12 months to allow thetopline to become stronger and more mature.

3. Results

Examination of the authors’ last 234 cervical injec-tions revealed that 70% underwent nuclear scintig-raphy before injection. In 56% of the cases, onlythe facet joints at C6-C7 were injected, whereas 34%(81/234) had C5-C6 and C6-C7 injected. In 9% (21/234) of the cases, the facet joints at C4-C5, C5-C6,and C6-C7 were injected. Overall client satisfac-tion was much higher (92%) when the facet jointswere injected based on history, clinical examination,IRU on a bone scan, and radiographs. If no bonescan was performed, the satisfaction with the cervi-cal injection was much lower (63%). In most cases(230/234), the cervical facet joints were injectedbilaterally.

4. Discussion

The diagnosis and treatment of topline issues canrepresent a significant challenge to the equine prac-titioner. Although diagnostic means have beentouched on in this report, treatment by injection isthe focus. In our practice, injection of the cervicalfacet joints is a relatively common procedure inhorses with problems of the axial skeleton, whereasinjection of the thoracolumbar facet joints, DSPs,and sacroiliac region are uncommon, simply becausewe have found other methods of managing thesecases to be effective. Horses with disorders of theaxial skeleton other than those affecting the cervical

Fig. 15. A linear probe is placed directly on midline to locate thedorsal spinous processes (DSPs).

Fig. 16. The resultant ultrasound image shows the caudal as-pect of the cranial DSP and the cranial aspect of the caudalDSP. The junction between the two is located in the center ofthe screen.

Fig. 17. Once the over-riding DSPs are located with ultrasound,a 25-gauge needle is introduced just abaxial to the probe andangled back toward midline. The injection is carried out on boththe left and right sides of the back.



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region appear to respond well to complementarytreatment and eccentric exercise.

Successful treatment of cervical arthrosis with in-tra-articular corticosteroids seems to imply that thepathology is somehow related to articular or periar-ticular inflammation.17 Most of the injections inour case load initially were with corticosteroids;however, recent applications have included the useof ACS.a Becker et al. used ACS successfully inpeople with lumbar radiculopathy.18 Other treat-ments for cervical issues may include acupuncture,massage, manipulation, or shock wave therapy.In horses that do not improve with intra-articularinjection and that have neurological deficits, cordcompression should be considered, and additionaldiagnostics in the form of a myelogram may be war-ranted.19 In most cases, the facet joints were in-jected from both the right and left sides, based onradiographic and/or scintigraphic evidence thatfacet arthrosis was present bilaterally. Unilateralfacet joint injection was a rare occurrence in our caseload and was usually performed when there was aunilateral forelimb lameness attributed to facetarthrosis.

Return to function after treatment of a cervicalarthropathy can be difficult to quantify, particularlybecause the clinical signs may be considered obscureto begin with; and, in some situations, the treat-ment has been combined with other therapies aimedat concurrent appendicular skeletal abnormalities.In cases in which ataxia is noted, return to exerciseshould only be with stern warnings and limitationsfor the safety of the rider and for legal reasons.In moderate to extreme cases of cervical compres-sion or unrelenting pain associated with the cervicalarthropathy, cervical body fusion has been success-fully used. Regression of the enlarged facet jointhas been documented with plain radiography andmyelography after cervical stabilization.20

In the horses with mild clinical signs associatedwith over-riding DSPs, improvement is relativelyeasy to quantify. The back pain and resistance toforward work subsides, and the horse returns to anormal athletic routine. In cases in which severeclinical signs are present, it becomes difficult to de-termine when the horse can return to work undersaddle. If the presenting signs include a horse thatbucks or rears violently when ridden, particularly ifthe owner is an amateur, the decision to return thehorse to work under saddle should be undertakenvery seriously, if at all. In severe cases of backpathology, retirement may be the best and mosthumane option. Surgical removal of the offendingDSPs has also been described as a successful methodof managing this disorder.

In our case load, it is not uncommon to see acombination of topline pathologies present in thesame horse. Horses with cervical arthrosis oftenhave some degree of sacroiliac soreness present andvice versa, begging the discussion as to which syn-drome preceded the other and which is more vital to

the horse and its future athletic function. Moreimportantly, cases of over-riding DSPs often haveissues associated with both the cervical and sacroil-iac regions. In such cases, treating the pathologyin the thoracolumbar region will only temporarilyimprove the horse because the underlying pathologyin the cervical and sacroiliac regions may be causingthe horse to “invert” its topline, leading to the de-velopment of the over-riding DSPs. In such ahorse, treatment of the cervical and sacroiliac dys-function, combined with “retraining” of the topline,can result in improvement or resolution of clinicalsigns. Retraining the topline may include canter-ing under saddle or lunging with a collection devicesuch as a Pessoa lunging rig. Such training modi-fications should be explored in conjunction with thetrainer and owner. The goal is to restore physio-logical function as quickly as possible, so the horse“rehabilitates” itself.21

The diagnosis of topline disorders in the horse canbe challenging enough, but the treatment of theseabnormalities can be a source of significant frustra-tion to the equine practitioner. This report ad-dresses in depth just one method of managing suchcases.

References and Footnotes1. Jeffcott LB. Disorders of the thoracolumbar spine of the

horse: a survey of 443 cases. Equine Vet J 1980;12:197–210.2. Turner TA. Back soreness in horses, in Proceedings. Am

Assoc Equine Pract 2003;49:71–74.3. Dyson SJ. The cervical spine and soft tissues of the neck. In:

Ross M, Dyson SJ, editors. Lameness in the Horse. 1st edi-tion. St Louis: Saunders; 2003:522–531.

4. Denoix JM, Pailloux JP. Concepts of neuromuscular physi-ology. In: Physical Therapy and Massage for the Horse.United Kingdom: Trafalgar Publishing, London; 1996:9–16,21–25.

5. Clayton HM, Townsend HG. Kinematics of the cervicalspine of the adult horse. Equine Vet J 1989;21:189–192.

6. Prakash S. Outcome in patients with cervical radiculopa-thy. Prospective multicenter study with independent clinicalreview. Spine 1999;24:591–597.

7. Lee AT, Lee-Robinson AL. The prevalence of medial epicon-dylitis among patients with C6 and C7 radiculopathy. SportsHealth: A Multidisciplinary Approach. 2010;2:334–336.

8. Martinelli MJ, Rantanen NW, Grant BD. Cervical arthrop-athy, myelopathy or just a pain in the neck? Equine VetEduc 2010;22:88–90.

9. Ricardi G, Dyson SJ. Forelimb lameness associated with ra-diographic abnormalities of the cervical vertebrae. Equine VetJ 1993;25:422–426.

10. Grisel GR, Grant BD, Rantanen NW. Arthrocentesis of theequine cervical facets, in Proceedings. Am Assoc Equine Pract1996;42:197–198.

11. Berg LC, Nielsen JV, Thoefner MB, et al. Ultrasonographyof the equine cervical region: a descriptive study in eighthorses. Equine Vet J 2003;35:647–655.

12. Neilson JV, Berg LC, Thoefner MB, et al. Accuracy of ultra-sound guided intra-articular articular cervical facet joints inhorses: a cadaveric study. Equine Vet J 2003;35:657–661.

13. Mattoon JS, Drost WT, Grguric MR, et al. Technique forequine cervical articular process joint injection. Vet RadiolUltrasound 2004;45:238–240.

14. Chope K. How to perform sonographic examination and ul-trasound-guided injection of the cervical vertebral facet jointsin horses, in Proceedings. Am Assoc Equine Pract 2008;54:186–189.





15. Cousty M, Firidolfi C, Geffroy O, et al. Comparison of me-dial and lateral ultrasound-guided approaches for periartic-ular injection of the thoracolumbar intervertebral facet jointsin horses. Vet Surg 2011;40:494–499.

16. Turner T. Overriding spinous processes (“kissing spines”) inhorses: diagnosis, treatment and outcome in 212 cases, inProceedings. Am Assoc Equine Pract 2011;57:424–430.

17. Birmingham SSW, Reed SM, Mattoon JS, et al. Qualitativeassessment of corticosteroid cervical articular facet injectionin symptomatic horses. Equine Vet Educ 2010;22:77–82.

18. Becker C, Heidersdorf S, Drewlo S, et al. Efficacy of epidu-ral perineural injections with autologous conditioned serumfor lumbar radicular compression: an investigator-initiated,prospective, double-blind, reference-controlled study. Spine2007;32:1803–1808.

19. van Biervliet J, Scrivani PV, Divers TJ, et al. Evaluation ofdecision criteria for detection of spinal cord compressionbased on cervical myelography in horses: 38 cases (1981–2001). Equine Vet J 2004;36:14–20.

20. Trostle SS, Grant BD, Bagby G, et al. Clinical results ofKerf Cylinder (Seattle Slew Implant) to reduce implant mi-gration and fracture in horses undergoing cervical interbodyfusion. Vet Surg 2003;32:5.

21. Haussler KK. Efficacy of manual therapies in the treatmentof thoracolumbar dysfunction, in Proceedings. Am AssocEquine Pract 2011;57:141–152.

aOrthokine, ORTHOGEN Veterinary GmbH; Dusseldorf, Ger-many.

bAmikacin, Ben Venue Laboratories, Bedford, OH 44146.cDormosedan®, Orion Corporation, Espoo, Finland.dSedivet®, Boehringer Ingelheim Vetmedica Inc., St. Joseph,

MO 64506.eTorbugesic®, Fort Dodge Animal Health, Fort Dodge, IA

50501.





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