SPONDYLOLISTHESIS SHOWN TO REQUIRE ADDITIONAL FUSION SEGMENT ONCE ITS DEGREE OF INSTABILITY, NOT VISIBLE BY RECUMBENT-ONLY MRI, WAS DEMONSTRATED BY FONAR UPRIGHT MRI

Clinical Case Overview 
The patient was a 49-year-old male who had had a 20-year history of chronic back pain and a three-year history of right lower extremity radiculopathy.

Prior to the Upright™ scan, the patient was scanned in a recumbent-only MRI (1.5T). It showed a right paracentral disk herniation at L5-S1. Based on the recumbent images, neurosurgeon Bennie W. Chiles III, M.D., said:

Neutral-Sit

Flexion

Extension

“I would have likely performed a diskectomy at L5-S1 to relieve pressure on the nerve root, along with an L5-S1 fusion for the back pain. Fusing L4-5 was not an initial consideration because no spinal instability was seen on the recumbent MRI.

When the dynamic flexion and extension images performed in the Upright™ MRI demonstrated an instability at L4-5 and showed the full extent of that instability once the patient’s body weight was applied, I chose to also fuse L4-5 during the procedure rather than treat L5-S1 alone.

The result was a better outcome for the patient whose severe right leg pain is now gone and whose back pain is much reduced.”

Bennie W. Chiles III, M.D., F.A.C.S.
Westchester Spine and Brain Surgery, PLLC
Hartsdale, New York,

Upright Imaging of Westchester, P.C.
Yonkers, New York

ICEHOCKEY PLAYER WITH POSTTRAUMATIC TRANSIENT SPINAL CORD INJURY (TSCI)

Clinical Case Overview 
Following a violent body check, a professional icehockey player experienced a sudden total quadraparesis that paralyzed him during play for a full minute. The upright flexion and extension images showed two centromedullary cord contusions where only one was visible on the neutral upright scan. The two contusions accounted for the quadraparesis that caused his sudden transient paralysis on the ice while playing.

Upright – Flexion

Neutral

Upright Extension

+ Parasagittal

The critically compromising stenosis at C 3-4, visualized only by means of the FONAR Upright™ MRI extension images in this athlete with a congenitally tight spinal canal, was responsible for the acute cord compression and centromedullary contusions that resulted in the acute transient paralysis (1 minute duration) of this athlete. His lesions were visible only on upright extension.

Following anterior decompression and interbody fusion with a composite cage, this hockey player, who might otherwise have had his professional athletic career terminated, was back on the ice competing, 3 months after surgery.

J.P. Elsig, M.D.
Orthopedic Surgeon
Fellow of the Swiss Orthopedic Society
Member of the Board of the Swiss Spine Society
FMRI Zentrum
Zurich, Switzerland

TRANSIENT QUADRIPARESIS WITH DROP ATTACK AND CHRONIC NECK AND ARM PAIN

Clinical Case Overview 
A 40-year old lady had been suffering for years from neck pain. A prior recumbent MRI had shown a C 5-6 disc degeneration with a posterior bulge and a moderate segmental kyphosis.

Despite repeated attempts with conservative treatment, the patient’s symptoms worsened and were marked by the onset of transient paresthesias, transit loss of muscle tone in the legs and drop attacks.

When the Upright™ MRI was performed, it showed both an increased disc protrusion and segmental kyphosis at C5-6 relative to the recumbent MRI (thick arrow), as well as, a descent of the cerebellar tonsils behind the arch of C1 (thin arrow) accompanied by brainstem compression (double arrow) against the odontoid process. This Chiara I Malformation, with position-related downward herniation through the foramen magnum visible only by means of the FONAR Upright™ MRI, explained the drop attacks and the transient loss of tone in the legs, which could not be accounted for by only the C 5-6 bulge seen on the recumbent MRI.

With the achievement of the correct diagnosis of the patient’s symptoms, made possible by the FONAR Upright™ MRI, the correct surgical treatment was accomplished and consisted of a posterior fossa decompression plus a C1 laminectomy and dural plasty. The C 5-6 herniation and kyphosis that was aggravated by the upright position was treated with an anterior C 5-6 discectomy and a cage placement.

J.P. Elsig, M.D.
Orthopedic Surgeon
Fellow of the Swiss Orthopedic Society
Member of the Board of the Swiss Spine Society
FMRI Zentrum
Zurich, Switzerland

SEVERE KYPHOSIS RENDERING RECUMBENT IMAGING IMPOSSIBLE

Sagittal images of the lumbosacral (6A) and thoracic (6B) spines in the upright-seated position shows compression of two thoracic vertebral bodies. This was ultimately found to be due to osteoporosis. The patient suffered from sufficiently marked kyphosis to render recumbent imaging impossible by either computed tomography or MRI.

Images courtesy of Imaging Center At Boot Ranch

LIGAMENTOUS RUPTURE ASSOCIATED WITH MOBILE ANTEROLISTHESIS

Anterolisthesis at L4/5 is noted in the recumbent view (4A). The standing flexion scan (4C) shows an interspinous ligamentous rupture at the L4/5 level (arrow).

Images courtesy of University of Aberdeen

POSITIONAL GENERATION OF CLINICAL SYMPTOMS

The recumbent image (15A) shows posterior disc protrusions at C5/6 and C6/7. Also note the adequate CSF space anterior to the spinal cord The upright-flexion image (15C) shows draping of the spinal cord over the posteriorly protruding discs. Clinically this patient exhibited L’Hermitte’s sign in the upright-flexion position.

BLADDER AND UTERINE PROLAPSE

The recumbent scan (9A) demonstrates no evidence of bladder or uterine prolapse and shows the levator sling is parallel to [and partially obscured by] the pubococygeal line. Note the decent of the bladder and uterus relative to the pubococygeal line which occurs with standing (9B) and is accentuated in the standing-straining view (9C). Note the levator sling (arrow) is oblique and non-parallel to the line when standing (9B), and straightens further when straining (9C).

POSITION-RELATED RECURRENT DISC HERNIATION

The recumbent scan for this patient with right-sided radiculopathy following partial discectomy is shown on the left. The upright scan (right) shows a disc herniation at L5/S1.

Images courtesy of Manuel S. Rose,
M.D.- Rose Radiology Centers 

EVALUATION OF SPINAL STABILITY

The recumbent scan (left) demonstrates minor degenerative anterolisthesis at L4/5. The upright-flexion study (right) reveals further anterior slip of L4 on L5. These scans show hypermobile translational spinal instability, which can be a surgical indication in a case of related low back pain.

Images courtesy of Melville MRI, P.C.

UPRIGHT DYNAMIC MRI REVEALS HIDDEN DISC HERNIATION

The axial standing-extension gradient echo image (right) demonstrates a focal posterior disc herniation at the C4/5 level not visible on the recumbent scan. Note the associated spinal cord compression on the standing-extension scan.

Images courtesy of Melville MRI, P.C

SEVERE SPONDYLOLISTHESIS UNDETECTED BY RECUMBENT MRI

Clinical Case Overview 
A 57-year old woman presented with pain of one year’s duration following failed back surgery performed in 2001*.

The patient continued to experience persistent low back-pain, accompanied by sensations of coldness and numbness in both thighs and legs. The patient often required mechanical support to stabilize her walking.

During the year following surgery, the patient sought help from multiple medical specialists. She provided her recumbent MRI images to them. She was told the images showed nothing that could account for her symptoms and that nothing more could be done. Her surgeon rejected the prospect of additional surgery. A Florida neurologist suggested to her that her problem was “in her head.”

Recumbent on Left – Upright on Right

The imaging center that evaluated her recommended she be scanned in an Upright™ MRI due to the possibility that an Upright™ scan, unlike the conventional recumbent scan, is weight-bearing and “might uncover something.” Her family physician wrote the prescription, and the patient drove from her home in the Florida panhandle to the closest FONAR Upright™ MRI center, which at the time was in Tampa over 425 miles away.

The patient was scanned in the patented FONAR Upright™ MRI in early 2002, one year after her spinal fusion. Both Upright™ and recumbent scans were performed on her in the multi-position FONAR Upright™ MRI.

The recumbent MRI (left image) exhibited only a normal lumbar lordotic curve and a modest bulge of the L3-4 intervertebral disc, consistent with her prior recumbent MRI scans. The FONAR Upright™ scan (right image) revealed, however, a marked position-dependent subluxation (anterolisthesis) at L3-4 and an accompanying spinal stenosis that were not visible on the recumbent MRI.

The patient’s Upright™ images established that there was a genuine physical basis for her symptoms, whereas her recumbent MRI images had failed to do so. The new Upright™ images supplied her surgeon with the necessary evidence that additional surgery was warranted to correct her problem.

A spinal fusion was performed at L3-4 one month after the patient’s Upright™ MRI scan. The surgical outcome was positive. To date, almost four years post-op, the patient remains symptom free and reported to FONAR, “Thank you for giving me my life back.”

* laminectomy and L45S1 fusion

Manuel S. Rose, M.D.
Radiologist
Rose Radiology Centers
Florida, USA

UPRIGHT DYNAMIC MRI REVEALS OCCULT DISC HERNIATION

“This MRI unit is important in that it enables the medical imaging specialist to uncover significant occult disease that is not apparent on the recumbent MRI studies”

J. Randy Jinkins, MD, FACR, FEC

Clinical Case Overview 
37 year-old male with bilateral pain and tingling in hands exacerbated upon flexion of the cervical spine.

Case Study
The images shown below were acquired on the Fonar Stand-Up™ MRI. The sagittal image in Figure 1 was acquired with the patient in a conventional recumbent position; Figure 2 is of the same patient, but in a standing position during extension. The standing-extension image demonstrates marked stenosis of the central spinal canal resulting from posterior disc protrusions extending into the anterior aspect of the spinal canal and focal ligamentous infolding posteriorly. Note that the resulting compression of the underlying spinal cord is not evident on the recumbent scan. (Scanning parameters for sagittal scans: TR= 3000 msec; TE = 160 msec; ETL = 15; 4.0 mm slice; scan time: 2:55 min – recumbent, 3:19 min – standing extension.)

Figure 1: Sagittal T2-weighted fast spin echo (FSE)
image in recumbent position

Figure 2: Sagittal T2-weighted FSE
image in standing position during extension 

The gradient recalled echo T2*-weighted axial images are from the same patient. The standing extension image (Figure 4) demonstrates a focal posterior disc herniation at C4/5 level that is not visible on the recumbent scan (Figure 3). Patient positioning and dynamic maneuvers clearly play a critical role in detecting clinically significant spinal pathology. Note that a final diagnosis based only on the recumbent scan would result in a missed pathologic diagnosis. (Scanning parameters for axial scans: TR = 506 msec; TE = 22 msec; FA = 20º; 4.0 mm slice; scan time: 5:04 min.)

Figure 3: Axial T2*-weighted gradient recalled echo (GRE) image of patient in recumbent position

Figure 4: Axial T2*-weighted GRE image of patient in standing-extension 

Diagnosis
Fluctuating intervertebral disc herniation dependent upon patient position and dynamic physical maneuver.

Professor J. Randy Jinkins, MD, FACR, FEC 
Department of Radiology
Downstate Medical Center
State University of New York
450 Clarkson Avenue
Brooklyn, NY 11203
USA

Clinical Studies performed at:
Melville MRI – Long Island

MELVILLE, NEW YORK, May 30, 2007 – FONAR Corporation (NASDAQ-FONR), The Inventor of MR Scanning™, announced today, that the April 23, 2007 issue of the Journal of Magnetic Resonance Imaging featured an article entitled ‘Upright MRI of glenohumeral dysplasia following obstetric brachial plexus injury’. In laymen’s terms, the study evaluated the effectiveness of upright MRI imaging for the diagnosis of a particular deformity in a child’s shoulder (glenohumeral dysplasia), which occurs as the result of an injury known as Obstetric Brachial Plexus Injury (OBPI), also known as Erb’s palsy. The authors conclude that “Upright MRI could, thus, serve as the standard procedure of care in pediatric obstetric brachial plexus population for glenohumeral imaging.” The study, which included 89 children, ages 0.4 to 17.9 years, with OBPI, was conducted on a FONAR UPRIGHT™ Multi-Position™ MRI operating at Natural MRI in Houston. Visit: http://mri.researchtoday.net/archive/3/4/2128.htm

The lead author-researcher in the study is Rahul K. Nath, M.D., Director of the Texas Nerve & Paralysis Institute and the Nath Brachial Plexus Institute at the Texas Medical Center in Houston, Texas. Dr. Nath, who has performed several thousand brachial plexus surgeries, is listed among America’s Top Doctors (Castle Connelly Publishers, 1st ed.). Less than 1% of American doctors achieve this honor, where Dr. Nath is the only physician listed in the category for Pediatric Brachial Plexus Management.

For more information on Dr. Nath visit: www.drnathbrachialplexus.comwww.drnathwingingscapula.comwww.drnathnervetumor.com 
www.drnathfootdrop.com
www.drnathmri.com

Dr. Nath said, “Old technology, such as recumbent MRI and CT scans, misses significant dislocations of the shoulder, in my experience. Because of what I learn about my patients’ pathology, that can only be seen on the FONAR UPRIGHT™ Multi-Position™ MRI, I have changed my surgical protocols. Examination of my post-surgical data shows that the Upright MRI definitely improves patient outcomes.”
“Using MRI to image patient pathology in the natural (weight-bearing) view is obvious,” added Dr. Nath. “The effects of gravity cannot be seen with other MRI machines.”

Dr. Nath continued, “As a surgeon, I need to be able to see the pathology of my patients in order to fix their problems. The FONAR UPRIGHT™ Multi-Position™ MRI gives me the necessary image quality that I need. But most important, by imaging patients in the ‘natural’ weight-bearing position, I am able to see the true pathology that gives me the best diagnoses. Because of this FONAR technology, I seldom use recumbent 1.5 Tesla scanners for my patients and am, in fact, dependent on the FONAR scanner.”

In the discussion of the results of the study, the authors state that “the images produced by upright MRI were of equal quality to those produced by recumbent MRI.” They also state, “Upright™ MRI has significant advantages to standard recumbent MRI, including the ability to view glenohumeral incongruence with gravity acting on the joint, as well as much reduced morbidity and expense in the pediatric population due to elimination of the need for sedation.”

According to the authors, “The relative beneficial aspects of Upright™ MRI include lack of need for sedation, low claustrophobic potential and, most important, natural, gravity-influenced position, enabling the surgeon to visualize the true preoperative picture of the shoulder. It is an effective tool for demonstrating glenohumeral abnormalities resulting from brachial plexus injury worthy of surgical exploration.”

SCIENTIFIC PAPER PRESENTED AT THE
EUROPEAN SOCIETY OF SKELETAL RADIOLOGY (ESSR)
OXFORD, ENGLAND, JULY 2005

Positional, Upright MRI Imaging of the Lumbar Spine
Modifies the Management of Low Back Pain and Sciatica

F.W. Smith, M.D., M. Siddiqui, University of Aberdeen, Scotland

——————————————————————————–

With the ability to image the lumbar spine using MRI in the Upright position, comes the question; Does this method of spinal imaging influence patient management?

Twenty-five patients referred for MRI of the lumbar spine 1 following at least one prior, “normal” MRI examination within six months of referral have been reviewed. 14 men and 12 women aged between 38 and 67 years of age were scanned using a 0.6T “Upright” MRI Scanner (FONAR New York). Each patient was scanned supine, standing erect and in the seated position. In the seated position images were made with the back in neutral, flexed and extended. Thus a series of five different positions were available for scrutiny. Sagittal T2 and Axial T2 weighted sections were made through the lower five intervertebral discs in each position.

In twelve cases, no significant abnormality was seen in any of the five postures. In thirteen, abnormalities were demonstrated in one or more of the seated postures that were not evident in the conventional supine examination.In three cases lateral disc herniation was only seen in the seated position. In six cases the presence of a hypermobile disc at one or more levels was demonstrated. In two cases previously unsuspected grade 1 spondylolisthesis was shown and in two cases significant spinal canal stenosis was seen in the seated extended position.

In 50% 2 of these cases that had previously been investigated for sciatica, a surgically remediable lesion was found. Each of the thirteen patients has undergone appropriate surgery and six months post surgery remain symptom free.

1. (for sciatica)

2. (52%, 13/25)

Source: http://www.essr.org/downloads/Scientific%20Presentations.pdf(pages 75-76)

EUROPEAN SOCIETY OF SKELETAL RADIOLOGY (EESR) 2004 – ABSTRACTS ORAL PRESENTATIONS

June 18-19, 2004 Augsburg, Germany
From www.essr.org-Augsburg2004

THE POTENTIAL VALUE OF MR IMAGING IN THE SEATED POSITION: A STUDY OF 116 PATIENTS SUFFERING FROM LOW BACK PAIN AND SCIATICA.

T. Muthukumar1, F.W. Smith2, D. Wardlaw2, M. Pope2. 1Robert Jones & Agnes Hunt Orthopaedic Hospital, Oswestry, UK, 2University of Aberdeen.

PURPOSE: The clinical symptoms of the lumbar spinal stenosis are often posture related. The availability of Open “Stand-Up” MRI enables images of the spine to be made in any posture. This study explores the potential of upright MRI scanning in neutral, flexion and extension in sitting and supine position of patients with low back symptoms.

MATERIALS & METHOD: 116 patients [45 female & 71 male] (Age 35 – 71 years, mean 44 years), suffering from low back pain and/or sciatica were studied. Each examination was performed using a 0.6 Tesla Open “Stand-Up” MRI. (FONAR, Melville, NY) MR Images were obtained in both the supine, seated neutral, seated flexed and extended positions.

RESULTS: Measurements from “Normal discs” show changes of only 1mm in disc height between supine and sitting, increasing to 2 – 4mm reduction in height anteriorly in forward flexion and between 2 – 4mm reduction in height posteriorly on extension Measurements from “Degenerate discs” show 1 – 3mm change in disc height between supine and sitting and significant reduction in disc height and position on flexion and extension. 108 prolapsed discs showed reduction of posterior prolapse on forward flexion & increase in extension, whilst 23 showed a decrease in posterior prolapse on extension. In 21 cases, the presence of a Grade 1 spondylolisthesis, not evident in the supine examination, was demonstrated in the seated position. In all cases, a degree of instability was demonstrated in the flexion and extension views.

21= 18%
116

In 4 cases of sciatica experienced whilst seated, in which the supine examination showed no abnormality, transforaminal disc herniation was demonstrated in the seated position.

CONCLUSION: We believe that the ability to image in the seated position is a major advance in the examination of the lumbar spine, especially in those patients with spondylolisthesis and position dependent disc prolapse.

RADIOLOGICAL SOCIETY OF NORTH AMERICA 2003
(RSNA): Scientific Papers
Neuroradiology/Head and Neck (My Aching Back)

THE POTENTIAL VALUE FOR MRI IMAGING IN THE SEATED POSITION: A STUDY OF 63 PATIENTS SUFFERING FROM LOW BACK PAIN AND SCIATICA

DATE: Thursday: December 04, 2004
START TIME: 11:00 AM
END TIME: 11:07 AM
LOCATION: ROOM N228
CODE: Q13-1312

PARTICIPANTS PRESENTER
Francis W. Smith, MD
University of Aberbeen, Scotland, U.K.

CO-AUTHOR: Malcolm Pope, PhD.

Keywords: Spine, MR

PURPOSE
With the availabilty of an MRI scanner capable of imaging in the erect postion and also open enough to allow for images of the lumbar spine to be obtained in flexion and extension, a study of 63 consequetive patients suffering from low back pain and sciatica referred for MRI examination was undertaken to assess what changes may be seen in different positions.

METHODS AND MATERIALS
Sixty three consecutive patients suffering from low back pain and/or sciatica, that had been referred for routine MRI examination, were studied. There were 20 female and 43 male patients aged 35 – 67 years of age (Mean 42 years). Each was exmined in a 0.6T Indominitable Stand-up MRI scanner (FONAR, Melville, New York). Sagital T1 and T2 images were made in the Supine and seated position. In the seated position the spine was imaged in neutral, flexed and extended. Transverse T2 weghted images were also made in neutral and in flexion. Each examination was evaluated by two trained observers.

RESULTS

56/63=89%
In all of the cases there were at least one intervertebral disc which showed a loss of signal from the nucleus on the T2 images. There was no difference in disc height between supine and seated in the healthy discs. In those showing loss of signal from their nuclei there was a reduction in heightof between 1 – 3 mm. In 56 cases there was obvious prolapse of an intervertebral disc, whose degree of prolapse changed between the neutral position and either flexion or extension. In 6 cases there was anterior movement of disc and superior vertebra, on forward flexion demonstrating previously unsuspected spinal instability. In the other case an unsuspected position dependant spondylolisthesis showing associated tear of the interspinous ligament was found.

CONCLUSION
The ability of MRI images to be obtained in flexion and extension enables a diagnosis of spinal instability to be made with confidence. The alteration in disc height and appearance between the three positions is of great interest and requires further detailed study in a larger group of patients.

RADIOLOGICAL SOCIETY OF NORTH AMERICA 2003

(RSNA): Scientific Papers
Neuroradiology/Head and Neck (My Aching Back)

MEASUREMENT OF DIURNAL VARIATION IN INTERVERTEBRAL DISC HEIGHT IN NORMAL INDIVIDUALS: A STUDY COMPARING SUPINE WITH ERECT MRI

DATE: Thursday: December 04, 2003
START TIME: 11:30 AM
END TIME: 11:37 AM
LOCATION: ROOM N228
CODE: Q13-1315

PARTICIPANTS PRESENTER
Francis W. Smith, MD
University of Aberbeen, Scotland, U.K.

CO-AUTHOR
Waseem Bashir MBBS
Yoichiro Hirasawa MD
Malcolm Pope PhD

Keywords: Spine, MR

PURPOSE
Circadian variation in human stature has been recognized since 1726.Diurnal height changes result from gravitational forces and are believed to result from changes in the intervertebral disc. With the availability of an MRI scanner which is capable of imaging in the erect as well as supine positions, it is now possible to study alterations in the appearances of the upright spine for the first time. This study measures disc height changes between morning and evening in both the erect and supine positions.

METHODS AND MATERIALS
32 male volunteers with no history of either low back pain or sciatica were studied using a 0.6Tesla indominitable pMRI scanner (FONAR). Each indiviual was examined supine and erect within 30 minutes of rising in the morning and again between eight and 9 hours later at the end of a normal working day. Each of the five intervertebral discs were measured using (a+p)/2, where a = anterior and p = posterior disc height. Measurements and interobserver reproducibility were performed independently by a radiolgist and an orthopaedic surgeon. Measurement results were analysed with one way ANOVA and multiple comparison post tests.

RESULTS
The cumulative loss of lumbar disc height for the five discs was between 7.70 – 8.09mm in the erect position and between 7.29 – 7.52mm in the supine position.

CONCLUSION
The length of the lumbar spine is about one third of the total body height and the intervertebral discs provide about 25% of this length. This study is unique in that it allows the spine to be assessed in the erect “naturally loaded” position. Given that the observed normal diurnal loss of height has been shown to be 17.00mm, one would expect that the loss over the lumbar region to be 8.5mm. The difference between this expected loss and our findings is accounted for by the alteration in lumbar lordosis between the erect and supine positions.

RADIOLOGICAL SOCIETY OF NORTH AMERICA 2003

(RSNA): Scientific Papers
Neuroradiology/Head and Neck (My Aching Back)

MEASUREMENT OF DIURNAL VARIATION IN INTERVERTEBRAL DISC HEIGHT IN NORMAL INDIVIDUALS: A STUDY COMPARING SUPINE WITH ERECT MRI

DATE: Thursday: December 04, 2003
START TIME: 11:30 AM
END TIME: 11:37 AM
LOCATION: ROOM N228
CODE: Q13-1315

PARTICIPANTS PRESENTER
Francis W. Smith, MD
University of Aberbeen, Scotland, U.K.

CO-AUTHOR
Waseem Bashir MBBS
Yoichiro Hirasawa MD
Malcolm Pope PhD

Keywords: Spine, MR

PURPOSE
Circadian variation in human stature has been recognized since 1726.Diurnal height changes result from gravitational forces and are believed to result from changes in the intervertebral disc. With the availability of an MRI scanner which is capable of imaging in the erect as well as supine positions, it is now possible to study alterations in the appearances of the upright spine for the first time. This study measures disc height changes between morning and evening in both the erect and supine positions.

METHODS AND MATERIALS
32 male volunteers with no history of either low back pain or sciatica were studied using a 0.6Tesla indominitable pMRI scanner (FONAR). Each indiviual was examined supine and erect within 30 minutes of rising in the morning and again between eight and 9 hours later at the end of a normal working day. Each of the five intervertebral discs were measured using (a+p)/2, where a = anterior and p = posterior disc height. Measurements and interobserver reproducibility were performed independently by a radiolgist and an orthopaedic surgeon. Measurement results were analysed with one way ANOVA and multiple comparison post tests.

RESULTS
The cumulative loss of lumbar disc height for the five discs was between 7.70 – 8.09mm in the erect position and between 7.29 – 7.52mm in the supine position.

CONCLUSION
The length of the lumbar spine is about one third of the total body height and the intervertebral discs provide about 25% of this length. This study is unique in that it allows the spine to be assessed in the erect “naturally loaded” position. Given that the observed normal diurnal loss of height has been shown to be 17.00mm, one would expect that the loss over the lumbar region to be 8.5mm. The difference between this expected loss and our findings is accounted for by the alteration in lumbar lordosis between the erect and supine positions.