ProActionClinic a mené plusieurs années de recherches et de synthèse de nombreux travaux scientifiques et a mis au point le coussin extensit.

Extensit est la bases d’une nouvelle stratégie d’approche des troubles posturaux et des maux de dos qui y sont probablement liés.



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Estudios Extensit

Scientific review for doctors, physiotherapists, chiropractors, osteopaths, pharmacists, orthopaedic technicians

Lumbar Extension: an additional preventive and therapeutic strategy effective in 50% of lumbar and lumbosciatic pain patients

The specific properties of the intervertebral discs, which act as sort of shock-absorbers between the vertebrae, mean they can normally bear additional loads, allow movement of the spine and dissipate the pressure due to gravity[1]. However, we know that each day the effects of gravity still cause the total height of the spinal column to gradually shorten with every hour. Weight-bearing, the numerous vibrations to which the body is subjected (travelling in cars, on public transport etc.) and simply sitting and standing are all factors that add to this loss of height.[2] [3] [4] [5] [6] [7]

This affects every level of the spinal column and every intervertebral disc is subject to these pressures. However, over time, they become less and less able to absorb them.

The cells in the intervertebral discs start to exhibit different biological responses depending on the mechanical stimulus they receive, which in turn depends on the overload, its intensity and duration and region of the disc being studied. This disc degeneration is accompanied by chronic dehydration and possible annular tears[8] [9].

Under the influence of overload, a moderate decrease in the glycosaminoglycan content of the disc nucleus is associated with rapid degeneration of the disc and alters its mechanical behaviour[10].

The structure of the disc cells changes, becomes disrupted and a certain percentage of cells dies[11].

It has also been shown that changes to one disc will lead to the gradual degeneration of the adjacent discs. This worsening degenerative cascade increases the instability of the spinal column[12] resulting in lumbar pain, radiculopathy and sciatica[13]. Many authors have concluded that degeneration of the intervertebral discs and adjacent end plates plays a determining role in lumbar pain[14] [15].

About lumbar extension...

However, these problems are to a certain extent avoidable and even reversible[16].

If we measure a patient who has been subjected to a 10 kg overload for 5 minutes we will find he has lost a certain amount of height. If this patient then lies down for 20 minutes, he recovers some of this lost height. However, if he lies in the lumbar extension position, the recovery in height is even greater[17].

The extension position therefore improves recovery by promoting disc hydration[18] [19].

Several MRI studies have demonstrated both the preventive and therapeutic benefits of lumbar extension. During flexion of the torso there is posterior displacement of the discs, and anterior displacement during extension[20] [21].

In other words, during anterior flexion the disc shifts towards the posterior elements (nerves, spinal cord, ligaments), irritating them and causing pain. With extension, the disc moves away from these elements helping alleviate the pain[22].

Disc problems such as herniation and posterior displacement which result in degeneration of the intervertebral disc are partially rectified in the extension position and much less so in the neutral position[23].

Subject to passing certain prior tests, the McKenzie Method for low back pain specifically recommends extension as a treatment of lumbar pain and sciatica[24] [25].

Studies of 39 and 140 patients have demonstrated that 60-70% of subjects can benefit from lumbar extension [26] [27].

Other studies of 148, 50 and 140 patients with acute lumbar pain or acute disc herniation confirmed the benefits of extension and its ability to prevent future pain episodes 24 [28] [29] [30].


[1] Boxberger, Sen, Yerramalli, Elliott. Nucleus pulposus glycosaminoglycan content is correlated with axial mechanics in rat lumbar motion segments. J orthop Res 2006 sep ;24 (9) : 1906-15. [2] Botsford DJ, Esses SI, Ogilvie-Harris DJ. In vivo diurnal variation in intervertebral disc volume and morphology. Spine. 1994 Apr 15;19(8):935-40.[3] Wisleder D, Smith MB, Mosher TJ, Zatsiorsky V.Lumbar spine mechanical response to axial compression load in vivo.Spine. 2001 Sep 15;26(18):E403-9.[4] Ohshima H, Tsuji H, Hirano N, Ishihara H, Katoh Y, Yamada H. Water diffusion pathway, swelling pressure, and biomechanical properties of the intervertebral disc during compression load.Spine. 1989 Nov;14(11):1234-44. [5] Adams MA, McMillan DW, Green TP, Dolan P. Sustained loading generates stress concentrations in lumbar intervertebral discs.Spine. 1996 Feb 15;21(4):434-8. [6] Malko JA, Hutton WC, Fajman WA. An in vivo magnetic resonance imaging study of changes in the volume (and fluid content) of the lumbar intervertebral discs during a simulated diurnal load cycle. Spine. 1999 May 15;24(10):1015-22. [7] Kimura S, Steinbach GC, Watenpaugh DE, Hargens AR. Lumbar spine disc height and curvature responses to an axial load generated by a compression device compatible with magnetic resonance imaging.Spine. 2001 Dec 1;26(23):2596-600. [8] Sarver JJ, Elliott DM. Altered disc mechanics in mice genetically engineered for reduced type I collagen. Spine. 2004 May 15;29(10):1094-8.  [9] Chiu EJ, Newitt DC, Segal MR, Hu SS, Lotz JC, Majumdar S. Magnetic resonance imaging measurement of relaxation and water diffusion in the human lumbar intervertebral disc under compression in vitro. Spine. 2001 Oct 1;26(19):E437-44.[10] Boxberger, Sen, Yerramalli, Elliott. Nucleus pulposus glycosaminoglycan content is correlated with axial mechanics in rat lumbar motion segments. J orthop Res 2006 sep ;24 (9) : 1906-15. [11] Rannou F, Lee TS, Zhou RH, Chin J, Lotz JC, Mayoux-Benhamou MA, Barbet JP, Chevrot A, Shyy JY. Intervertebral disc degeneration: the role of the mitochondrial pathway in annulus fibrosus cell apoptosis induced by overload .Am J Pathol.2004Mar;164(3):915-24. [12] Fujiwara A, Tamai K, An HS, Kurihashi T, Lim TH, Yoshida H, Saotome K.The relationship between disc degeneration, facet joint osteoarthritis, and stability of the degenerative lumbar spine. J Spinal Disord. 2000 Oct;13(5):444-50.[13] Luoma K, Riihimaki H, Luukkonen R, Raininko R, Viikari-Juntura E, Lamminen A. Low back pain in relation to lumbar disc degeneration Spine. 2000 Feb 15;25(4):487-92.[14] Albert HB, Kjaer P, Jensen TS, Sorensen JS, Bendix T, Manniche C. Modic changes, possible causes and relation to low back pain. Med Hypotheses. 2008;70(2):361-8.  [15] Tue S Jensen, Tom Bendix*, Joan S Sorensen*, Claus Manniche,* Lars Korsholm*, Per Kjaer.    Characteristics and natural course of vertebral endplate signal (Modic) changes in the Danish general population. BMC Musculoskeletal Disorders 2009, 10:81doi:10.1186/1471-2474-10-81.[16] Johannessen W, Vresilovic EJ, Wright AC, Elliott DM. Intervertebral disc mechanics are restored following cyclic loading and unloaded recovery.Ann Biomed Eng. 2004 Jan;32(1):70-6.[17] Magnusson ML, Pope MH, Hansson T. Does hyperextension have an unloading effect on the intervertebral disc? Scand J Rehabil Med. 1995 Mar;27(1):5-9. [18] Magnusson, Marianne L. DrMedSc *; Aleksiev, Assen R. PhD, MD *+; Spratt, Kevin F. PhD *; Lakes, Roderic S. PhD ++; Pope, Malcolm H. DrMedSc, PhD. Hyperextension and Spine Height Changes. Spine. 21(22):2670-2675, November 15, 1996.[19]Kourtis D, Magnusson ML, Smith F, Hadjipavlou A, Pope MH. Spine height and disc height changes as the effect of hyperextension using stadiometry and MRI.Iowa Orthop J. 2004;24:65-71. [20] Parent EC, Videman T, Battie MC. The effect of lumbar flexion and extension on disc contour abnormality measured quantitatively on magnetic resonance imaging.Spine. 2006 Nov 15;31(24):2836-42.[21] Edmondston SJ, Song S, Bricknell RV, Davies PA, Fersum K, Humphries P, Wickenden D, Singer KP. MRI evaluation of lumbar spine flexion and extension in asymptomatic individuals Man Ther. 2000 Aug;5(3):158-64.[22] Fennell AJ, Jones AP, Hukins DW. Migration of the nucleus pulposus within the intervertebral disc during flexion and extension of the spine. Spine. 1996 Dec 1;21(23):2753-7.[23] Parent EC, Videman T, Battie MC. The effect of lumbar flexion and extension on disc contour abnormality measured quantitatively on magnetic resonance imaging. Spine. 2006 Nov 15;31(24):2836-42.[24] La méthode MCKenzie, Revue de médecine orthopédique, n°60, Mars 2000.[25] La Méthode MCKenzie de prise en charge des douleurs lombaires mécaniques. Evaluation, Classification. Ron Donelson , The MCKENZIE institut, Hanover NH USA[26] Delitto A, Cibulka MT, Erhard RE, Bowling RW, Tenhula JA.  Evidence for use of an extension-mobilization category in acute low back syndrome: a prescriptive validation pilot study.Phys Ther. 1993 Apr;73(4):216-22.[27] Hefford C. McKenzie Classification of mechanical spinal pain: Profile of syndromes and directions of preference.Man Ther. 2006 Dec 21.[28] Kopp JR, Alexander AH, Turocy RH, Levrini MG, Lichtman DM. The use of lumbar extension in the evaluation and treatment of patients with acute herniated nucleus pulposus. A preliminary report. Clin Orthop Relat Res. 1986 Jan;(202):211-8.[29] Machado LA, Maher CG, Herbert RD, Clare H, McAuley J. The McKenzie Method for the management of acute non-specific low back pain: design of a randomised controlled trial. BMC Musculoskelet Disord. 2005 Oct 13;6:50. [30] Clare HA, Adams R, Maher CG. Construct validity of lumbar extension measures in McKenzie's derangement syndrome.Man Ther. 2006 Sep 11; 16.



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