The premise of spinal decom-pression is to apply an axial (Y-axis) tension to the pelvic brim

to create a demonstrable and suffi-cient unloading of the disc. Axial trac-tion is a necessary component in thegeneration of a reduced or negativepressure gradient in the disc. Since thedisc is an isotropic structure (its pres-sure changes when variations of com-pression and tension are applied), itcan also generate a centripetal-likeeffect within a hydrostatic nucleuswhich could theoretically “drawinward” escaped nuclear material.The outward nuclear migration beingpossible due to a separation across theannular lamina, the so called radialfissure. If the outer wall is bulged butnot breached i.e. still contained, then itis possible a reduced or negative pres-sure could reduce the outer annularprotrusion — at least during the trac-tion application.

Much research has been published(there is a large inventory of suchresearch at www.kennedytech-nique.com) showing that the reduc-tion of outer-wall protrusions viaaxial traction is not just possiblebut apparent. At least 4 studieshave been conducted in vivo andseveral in vitro demonstrating thattraction draws-inward annular pro-trusions. Many of these studies weredone during traction in a CT scanner,x-ray or videofluroscopy.

As tension is applied to a malleabletube its cross-sectional diameterreduces (Poisson’s effect). This createsa mechanical inward pressure as wellas a fluid alteration, the centripetaleffect. This is very important to themechanism and anatomy of the

human disc as it has little if nodirect blood supply and requiresimbibition through osmotic fluidexchange (diffusion). Motion andrecumbent rest facilitate this dailyphenomena, however it is recognizedthat inefficient segmental motion(either hyper or hypomobility) willalter this metabolic exchange. In mostcases adverse mechanical loading(compression) over time creates a direcondition of slow degradation of thedisc, often at just one primary level,other times at multiple levels.

Bogduk et al., have pointed out thatthe inner annulus has such a slowmetabolic rate as to be “barely ade-quate to sustain itself.” Further, end-plate damage during youth, especiallycontact sports, will impair the normalexchange of nutrients to the nucleuscreating a high likelihood of internaldisc disruption in early or middle

adulthood and a subsequent herniateddisc when a mundane additional com-pression or torque is applied. Whenwe add to this a 70 percent familiallikelihood of same-level disc degener-ation (as determined from mono-zygomatic twin studies), it becomesapparent disc troubles are endemic,and decompression traction therapy areasonable and sensible treatmentoption for the disc.

Decompression system manufacturersand marketers have decades of excel-lent literature, graphics and theoreti-cal explanations of the action of discdecompression. Though much of it is

still theoretical, it affords the doctorand the public a reasonably accurateand insightful assessment of thepotential of the therapy. There areseveral animal studies which add aphysiologic analysis as well to theactual disc-structure mechanism as aresult of overt compression and subse-quent distraction. I have always likedto suggest to patients that dramatic“physical” alterations from the thera-py are minimal (there is no discernibletissue creep resulting an hour post

traction); however, dramatic internal,physiologic reactions occur.

Again Bogduk has described this as aphasic, physiologic phenomenon.What occurs is during and soon afterthe traction is applied. The mechanicalact of distraction acts as a trigger torenewed metabolite transport andpossible improved binding via colla-gen fibers across the radial tear. Irre-spective of its direct provability, it is avery reasonable scenario to describethe often remarkable long-term reliefmany HNP patients describe.

Certainly if the relief was mechanore-

32 DC PRODUCTS REVIEW • SEPTEMBER 2013

by Dr. Jay Kennedy

Thoracic RestraintOptions For Axial

DecompressionTherapy

The mechanical act of distraction acts as a trigger to renewedmetabolite transport and possible improved binding viacollagen fibers across the radial tear.

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ceptor activity, the results should bevery fleeting. Of course sometimesthey are (as with any therapy), butoften they are long-term or even cura-tive in some. Most clinical researchersand even insurance medical directorsunderstand the premise and potentialof traction in disc compression condi-tions — irrespective of the dearth of“class A” research. Studies suggesttraction, added to other therapy pro-grams, may give better short-termimprovement in recalcitrant patientswith HNP with sciatic symptoms, anda positive cross-leg raise test.

So, most of us shouldn’t necessarilyneed to be coerced into accepting thepremise or the advantages of decom-pression therapy. A cursory check onthe internet will allow most of us rec-ognize the financial benefits of decom-pression as well. We have been sug-gesting for ten years that a chiroprac-tor either have decompression thera-py or compete against it. In mostmajor markets and in many verysmall ones as well, this is truly thecase. Many doctors have opened disc-specific treatment centers utilizingdecompression and a modality likehigh powered laser and some exercisetherapy. This more esoteric approachhas helped create a lot of wealth formany DCs in the last decade or so.

To create this negative disc pressure(decompression) three componentsare necessary: a decompression/trac-tion machine, a harness to transferthe force to the axial dimension ofthe patient, and a thoracic restraint.Without all three, efficient traction isimpossible. The harness is securedaround the abdomen and engagesthe pelvic brim; a non-slipping har-ness is a necessity. A traction motorcreates the axial pulling force and theonly remaining component is to makesure the thorax stays securely in placeso the result is a separation of thelower vertebra.

Over the last forty years very fewinnovations in thoracic restrainthave been created. In fact, in morethan ninety percent of physicaltherapy clinics, a so-called wing-vestis the only thing available. Thoracic

wing vests/harnesses will effectivelystop caudle slippage; however, theyare not without difficulties, such asmisapplication by doctor and staffalike. The thoracic vest has to grabunder the lower ribs and thus canhave a very marked effect on breath-ing. It often stirs up claustrophobiaas well. I’ve not seen the pelvic har-ness create claustrophobia, but I’veseen the thoracic vest do it often. Afew studies have demonstratedincreased lumbar muscle activitywhile being tractioned with a tightthoracic harness. Static traction appli-cation presents even more issues withthis form of restraint.

The most important innovations intraction thoracic restraint in the last 20years have come in the form of han-dle-bars and hand-hold bars wherethe patient restrains their slide viatheir outstretched arms and grip. Sev-eral systems (prone) have installedhandle hold bars and several havearm rests to facilitate a reduction inshoulder strain common if the armsare forced to stay overhead. Ourresearch has shown most patients pre-fer an arm-down traction table withhandles beneath. This form ofrestraint offers numerous advantagesand no real problems — even at veryhigh forces. Choke blocks (slipstopmaterial), which easily slide under thepatient’s ribs (prone or supine), offer aquick and convenient restraint forlower-force sessions on the elderly,claustrophobic or frail.

The most efficient method isadjustable axilla posts that can beused by virtually anyone in the supinetraction position. They give amplerestraint, can be used along with anyother restraints, and afford a near zeropossibility of misapplication. Properrestraint of the thorax is not only anecessity for proper and efficient lum-bar-distraction (generating discaldecompression), but also for the com-fort and confidence of the patient.

About The Author — Dr. Kennedy hasdeveloped, tested and taught a highlyeffective, easy-to-learn chiropracticdecompression therapy technique.

DC PRODUCTS REVIEW • SEPTEMBER 2013 33

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