JOURNAL OF BONE AND MINERAL RESEARCH Volume 7, Number 12, 1992 Mary Ann Liebert, Inc., Publishers

Osteoporosis and Chronic Back Pain: A Study with Single-Photon Emission Computed Tomography Bone Scintigraphy P. J. RYAN,',' P. EVANS,' T. GIBSON,' and I. F O G E L M A N '

ABSTRACT

A group of 26 patients aged 47-81 years (average 67) with spinal osteoporosis and back pain for more than 6 months were investigated with planar and SPECT bone scintigraphy and anterior and lateral x-rays of the thoracolumbar spine. Abnormal activity on bone scintigraphy was found in all patients, of whom 22 had multiple lesions. A total of 17 (65%) patients had abnormal activity associated with collapsed vertebral bodies, 5 (19%) had degenerative disk disease, and 21 (81%) had facetal joint disease. Of 112 lesions identified by SPECT, 60 (54%) were localized to the apophyseal joints. Facetal lesions were commoner in those patients with more collapsed vertebrae, and 32 facetal lesions (54%) were associated with collapse of the vertebra immediately above or below. Bone scintigraphy findings suggest that in some individuals with osteoporosis and chronic back pain, collapse of the vertebral body or degenerative disk disease are causes of pain. However, the high frequency of increased apophyseal joint activity suggests that the facet joints may also be an important site of origin of pain in these individuals. Bone scintigraphy may identify a subgroup of osteoporotic patients with chronic back pain who would benefit from treatment to the facet joints.

INTRODUCTION is typically acute, lasting for a few weeks from the onset of vertebral collapse.") However, some patients with crushed vertebrae may also develop chronic back pain, which can be severe and disabling."] This has been demonstrated to be related to the degree of spinal deformity(2)and in some studies to the number and severity of collapsed vertebrae. 0 ) However, it has also been shown that osteoporotic vertebral collapse is no more common in patients with chronic low back pain than in those w i t h o ~ t , ' ~suggesting .~] that the detection of a crush fracture does not necessarily imply it is the cause of pain. Degenerative disk disease may also be found in these patients but is also commonly found in asymptomatic individuals.(sl Thus, in clinical practice the aetiology of chronic back pain in osteoporotic individuals is often uncertain. A precise diagnosis may not be established and treatment directed at the symptoms rather than the cause.

B

ACK PAIN IN OSTEOPORISIS

Bone scintigraphy provides a sensitive technique for the detection of altered skeletal metabolism associated with bone pathology, and a previously reported small study of patients at risk for osteoporosis with severe back pain investigated with planar scintigraphy showed abnormalities in 15 of 19 cases.'') In the spine, the addition of single-photon emission computed tomography (SPECT) has further improved the sensitivity of bone scintigraphy and enabled better localization of activity to specific sites in the vertebra,(*)such as the facet joint, where disease is difficult to demonstrate on radiograph~.'~) The bone scan with SPECT in patients with osteoporosis and chronic back pain may therefore help identify sites from which pain originates and thus aid decisions regarding therapy. The aim of this study was to investigate the bone scan findings in such individuals.

MATERIALS AND METHODS A group of 26 patients age 47-81 years (average 67), 25

'Department of Nuclear Medicine, Guy's Hospital, London, England. 'Department of Rheumatology, Guy's Hospital, London, England.

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females and 1 male with known osteoporotic collapse diagnosed on lateral spine x-ray and following this continued back pain for at least 6 months (average 8 months), were investigated with anterior and lateral x-rays of the thoracolumbar spine and bone scintigraphy with SPECT. The patients studied were consecutive referrals with these clinical characteristics to a specialist metabolic bone clinic. Vertebral collapse was established from the presence of wedge, biconcave, or compression fractures as defined by the method of Eastell et al.(la)Anterior (ha), middle (hm), and posterior (hp) heights of vertebrae were measured. From these measurements, wedge deformities were defined as from (hp - ha)hp x 100, biconcave deformities from (hp - hm)/hp x 100, and compression deformities from (hp' - hp)/hp' x 100, where hp' is the posterior height of the vertebra above or below or the nearest adjacent normal vertebra. Abnormal vertebrae were those in which one of these measurements was > 3 standard deviations from normal values. Normal values were defined from measurements of the anterior, middle, and posterior vertebral heights in 50 normal individuals aged 40-65 years without radiologic evidence of spinal fracture or history of factors that may affect bone mass and who had normal densities for age. Anterior and lateral x-rays were also analyzed for the presence of disk degeneration, osteophytes, and facetal sclerosis. Bone scintigraphy was performed within 1 month of the x-rays. Planar bone scan views of the axial skeleton were obtained 3 h after the injection of 750 MBq [WmTcIMDP (methylene diphosphonate). Following planar imaging, SPECT views of the lumbar spine were obtained using a Starcam 400 ac single-head camera. A total of 64 projections were taken around a 360" orbit with 20 s per projection and acquisition into a 128 x 128 matrix. The principal symptomatic region was positioned in the center of the field of view (FOV). Of 26 patients, in 4 the FOV was centered over the thoracic spine and in 22 over the lumbar spine. Following filtered backprojection using a Hanning filter with a 0.8 high-frequency cutoff, transaxial, coronal, and sagittal slices were generated. X-rays were reported by a radiologist familiar with reporting spinal x-rays. Bone scintigraphy findings were reported independently by a nuclear medicine physician familiar with bone scintigraphy with SPECT, who was blind to the radiologic findings. Planar bone scintigraphy lesions were described as predominantly focal or predominantly linear. Anterior

SPECT lesions were described as focal (< 50% vertebral body) or whole (>50% vertebral body). SPECT lesions detected in the posterior elements were localized to individual parts of the posterior neural arch. All bone scan lesions were graded as mild, moderate, or severe.

RESULTS A total of 15 patients had collapsed lumbar vertebrae and 22 patients collapsed thoracic vertebrae, with an overall average number of crushed vertebrae of 3.7 (range 110). X-ray changes in lumbar spondylosis (disk degeneration and/or osteophytosis) were found in 1 1 patients, of whom 1 also had evidence of facetal osteoarthritis. Of 26 patients, all except 1 had lesions on planar bone scintigraphy, and 22 had multiple lesions. Facetal joint lesions were found in 21 patients (810/0), and vertebral body lesions were also found in 21 patients (81%). Whole vertebral body lesions associated with vertebral body collapse were found in 17 (65%) and vertebral body bone scan lesions associated with degenerative disease were found in 5 patients (19%). Of 112 total bone scan lesions only 71 (63%) were demonstrated by planar imaging alone. Of 34 linear planar lesions, all were localized to the vertebral body and involved the whole vertebral body. Of 36 planar focal lesions, 24 (67%) were localized to the facetal joints and 1 1 (31%) to

TABLE1 . DISTRIBUTION OF PLANAR AND SPECT SCINTIGRAPHIC LESIONS

Planar lesions Focal 36

Linear 34 Planar negative 42

SPECT lesions Facet joint 24 Focal body 10 Wholebody 1 Spinous process 1 Wholebody 34 Facet joint 36 Focal body 4 Wholebody 1 Spinous process 1 Total 112

TABLE2. X-RAY ABNORMALITIES ASSOCIATED WITH BONESCAN LESIONS

X-ray abnormalities (%)

Disk degeneration or Bone scan lesion Facet joint Focal body Whole body Spinous process

60 14 36 2

Vertebral collapse

osteophytes

None

32 (54) 4 (29) 29 (80) 0

2 (3) 7 (50) 1 (3) 0

26 (43) 3 (21) 6 (17) 2 (100)

OSTEOPOROSIS IN BACK PAIN the vertebral body. A total of 60 lesions (54%) were localized by SPECT to the facetal joints and 50 (45%) to the region of the vertebral body, 36 whole body, and 14 focal body (Table 1). Of the 60 facetal lesions, 9 (15%) were severe, 27 (45%) moderate, and 24 (40070)mild. Of the 36 whole-body lesions, 6 (17%) were severe, 13 (36%) moderate, and 17 (47%) mild. Of 42 lesions only detected by SPECT, 20 (48%) were mild, 20 (48%) moderate, and 2 (4Or0) severe, and 36 (86%) were localized to the facetal joints. No lesions were identified elsewhere in the posterior neural arch, apart from 2 in the spinous process. X-ray changes of vertebral collapse of lumbar spondylosis associated with bone SPECT findings are shown in Table 2. Of the 36 anterior bone scan lesions involving the whole vertebral body, 29 (81%) were at the same level as vertebral collapse on x-ray. Multiple whole-body lesions associated with vertebral collapse were found in 7 patients, in all of whom there was variation in intensity of the lesions (Fig. 1). Of 14 focal anterior lesions, 4 (29%) were at the same spinal level as vertebral collapse on x-ray, 7 (SOTO)were at the same level as vertebral disk degeneration and/or osteophytosis, and 3 were not associated with any x-ray abnormality. Of the 60 apophyseal lesions, 32 (54%) were found at the spinal level above or below a collapsed vertebra vertebra, 2 associated with degenerative change at

1457 the level of the lesion, and 26 (54%) without any x-ray abnormality. A total of 27 (45%) of facetal lesions were found at L4-5 or L5-S1. Of the 33 facetal lesions above L5-Sl, 24 (73%) were found at the level immediately above or below vertebral collapse (Fig. 2). The numbers of facetal and whole anterior lesions found in patients with different numbers of collapsed vertebrae is shown in Table 3. The average number of facetal lesions in patients with 1 vertebral fracture (7 patients) was 1.7, 2-4 fractures (9 patients) 2.3, and 5-10 fractures (10 patients) 3.0. The average number of whole anterior lesions in those with 1 vertebral fracture was 0.7, 2-4 fractures 1 . 1 , and 5- 10 fractures 2.1. A further comparison was made between the bone scan findings and spinal level at which back pain was felt (Table 4). Of 26 patients, 15 had lumbar back pain, 2 patients had thoracic back pain, and 9 had both. Of 24 patients with lumbar back pain, 21 had lumbar spine facetal lesions, 6 whole-body lesions, and 3 focal lesions. A total of 1 1 patients (46%) with lumbar back pain had only facetal lesions in the lumbar spine, Of 1 1 patients with thoracic back pain, 5 had thoracic facetal lesions, 8 whole-body lesions, and 1 a focal lesion. A total of 5 patients (45%) with thoracic back pain only had whole-body lesions in the thoracic spine on bone scan.

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B

-

TRANSAXIRL

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...

FIG. 1. (A) Posterior planar view from patient with increased activity associated with multiple collapsed vertebrae. (B) Planar and SPECT bone scan images of the same patient showing variation in activity from several collapsed vertebrae (arrows) and the typical whole anterior pattern of vertebral body uptake associated with vertebral collapse on the transaxial slice.

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FIG. 2. (A) Posterior planar view showing increased activity at TI2 and focal activity above and below. (B) Planar and SPECT images from the same patient showing activity associated with vertebral collapse at T12 and associated with facetal joints at TI 1-12 and T10-11 (arrows).

TABLE 3. EFFECTOF

VERTEBRAL

COLLAPSE ON BONESCAN

AND

X-RAY LESIONS

Bone scan Number collapsed vertebrae

Number patients

Mean age ~~

1

2-4 5-10

7

9 10

63 66 71

Facetal lesions (mean)

Whole anterior lesions (mean)

Number patients with x-ray changes of disk degeneration, osteophytes

~

1.7

2.3 3.0

DISCUSSION In this study of 26 patients with osteoporotic collapse and chronic low back pain, bone scan abnormalities were found in all cases. The majority of lesions (54%) were localized by SPECT to the facetal joints, and such lesions were found in 21 patients (81%). Although increased activity on bone scintigraphy does not necessarily identify the site as the cause of pain, it identifies a focus of abnormal

0.7 1.1 2.1

2 5 4

metabolic activity. In a patient who is symptomatic, it is probable that this is relevant. Evidence supporting facet activity on the bone scan identifying the source of pain comes from a study of 50 patients with low back pain, in which it was found that uptake on the bone scan predicted successful response to injection of these sites with local anesthetic. ( I 1 ) In some of the study patients, increased facetal activity may have resulted from osteoarthritis, which is common at

OSTEOPOROSIS IN BACK PAIN

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TABLE4. PATTERN OF BONESCANABNORMALITY IN THE LUMBAR AND THORACIC SPINEIN PATIENTS WITH BACKPAIN AT THESESITES Number of patients

Bone scan lesion pattern Facet joint only Whole body only Focal body only Facet joint + whole body Facet joint + focal body Whole body + focal body Facet joint + whole body + focal body None Total

Lumbar pain

Thoracic pain

11 1 2 4

1 5 0 3

5

1

0

0

1

0

0 24

1 11

In the majority of patients, lesions were present in the facetal joints, suggesting that in addition to vertebral body collapse, the apophyseal joint may also be a common source of pain in osteoporotic individuals with chronic back pain. This is supported by the finding that in patients with lumbar back pain, in 46% the only bone scan abnormality was increased uptake in the facetal joints. Treatment of facet joint disease, for example by injection with corticosteroid, has been questioned. ‘I4) However, results may be improved in selected patients by limiting injection to facet joints with increased activity on bone scintigraphy. A recent pilot study showed 60% of patients with chronic back pain without osteoporosis achieved complete relief of pain or were markedly improved 3 months after their active facetal joints were injected with 40 mg methylprednisolone.(ls)If similar results over a longer period could be achieved in a randomized clinical trial of selected osteoporotic patients with chronic back pain, this treatment could prove to be of considerable clinical benefit.

REFERENCES this age(12)and which has been demonstrated in patients with chronic low back pain without osteoporosis by SPECT and CT. ( 9 ) The true prevalence of facetal osteoarthritis is unknown in the present stdy, because x-rays are a poor method of detection. The finding of 45% of facetal lesions at L4-5 or L5-Sl supports the hypothesis that the increased facetal activity in some patients is due to apophyseal osteoarthritis because these are common sites for its occurrence. However, over 50% of all facetal lesions and over 70% of those above L4-5 were found immediately above or below the level of a collapsed vertebra in the absence of any degenerative disease on x-ray, which may imply an alternative cause, such as altered stress on the facetal joints secondary to vertebral collapse. This is supported by the finding of more facetal lesions in those patients with more collapsed vertebrae. Furthermore, it is of note that there is a higher prevalence of facetal joint activity in these patients than in a bone scintigraphy study of 80 consecutive patients presenting to a rheumatology department with chronic back pain in whom only 30% had facet joint disease. (I3) Increased bone scan activity at the same level as degenerative disease occurred in only five patients and, in these, could be a possible explanation for their symptoms. Also, 65% of patients had increased activity involving the whole vertebral body associated with x-ray changes of vertebral collapse. Moreover, of the 11 patients with thoracic back pain, the only bone scan abnormality in the thoracic spine in 45% was increased whole-body activity. In such patients prolonged pain may be due to a crushed vertebra itself either because of delay in resolution of symptoms or because of sequential fractures occurring in a short time interval. The latter mechanism may be relevant in seven patients who had multiple collapsed vertebrae with whole vertebral body tracer uptake of varying intensity, reflecting probable variation in time of onset of collapse.

1. Lyritis GP, Mayasis B, Tsakalakos N, et al. 1989 The natural

history of the osteoporotic vertebral fracture. Clin Rheumato1 ~ ( S U P P2):66-69. ~. 2. Leidig G, Minne HW, Sauer P, Wuster C, Wuster J, Lojen M, Raue F, Zeigler R 1990 A study of complaints and their relation to vertebral destruction in patients with osteoporosis. Bone Miner 8:217-229. 3. Ross PD, Ettinger B, Davis JW, Melton LJ 111, Wasnich RD 1991 Evaluation of adverse health outcomes associated with vertebral fractures. Osteoporosis Int 1:134-140. 4. Zetterberg C, Mannius SIV, Mellstrom D, Rundgren AKE, Astrand K 1990 Osteoporosis and back pain in the elderly. A controlled epidemiologic and radiographic study. Spine 15: 783-786. 5 . Symmons DPM, Van Hemert AM, Vandenbroucke JP, Valkenburg HA 1991 A longitudinal study of back pain and ra-

6.

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diological changes in the lumbar spine of middle aged women. 1 I . Radiographic findings. Ann Rheum Dis 50:162166. Copper C, Shah S, Hand DJ, Adams J, Compston J, Davie M, Woolf A, 1991 Screening for vertebral osteoporosis using individual risk factors. Osteoporosis Int 2:48-53. Gupta SM, Tung M, Spencer RP, Maturlo S, Davies T, Herrera NE 1988 Nuclear medicine studies of aging. VI. Dual photon absorptiometry and bone scans in “at risk” women with back pain. Nucl Med Biol 15629-630. Collier BD, Hellman RS Jr, Krasnow AZ 1987 Bone SPECT. Semin Nucl Med 17:247-266. Ryan PJ, Evans P , Gibson T, Fogelman I 1992 Chronic low back pain: Comparison of bone SPECT with radiography and CT. Radiology 1822349-854. Eastell R, Cedal SL, Wahner HW, Riggs BL, Melton LJ I11 1991 Classification of vertebral fractures. J Bone Miner Res

6~207-215. 11. Scott A, Schwartzer A, Cooper R, Hoschi R, Wiseman JC, Coote D 1991 Diagnosis of facet joint arthritis in patients

with low back pain-comparison of SPECT and planar bone scintigraphy and facet joint injection (abstract). Aust N Z SOCNucl Med 84. 12. Carrera GF, Haughton VM, Syvertsen A, Williams AL 1980

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1460 Computed tomography of the lumbar facet joints. Radiology 134:145-148. 13. Ryan PJ, Fogelman I , Gibson T 1991 Bone scintigraphy with SPECT in low back pain (abstract). Eur Cong Rheumatol

236. 14. Carrette S, Marcoux S, Truchon R, Grondin C, Gagnon J, Allard Y, Latulippe M 1991 A controlled trial of cortico-

steroid injections into facet joints for chronic low back pain. N Engl J Med 325:1002-1007. 15. Ryan PJ, Di Vadi P, Gibson T, Fogelman I 1992 Facet joint injection in patients with low back pain and increased facetal activity on bone scintigraphy with SPECT: A pilot study (ab-

stract). Nucl Med Commun 13:401.

Address reprint requests to: Dr. P.J. Ryan Department of Nuclear Medicine

Guy’s Hospital St. Thomas’ Street London SEI 9RT UK Received in original form March 2, 1992; in revised form June 8, 1992; accepted June 30, 1992.

Osteoporosis and chronic back pain: a study with single-photon emission computed tomography bone scintigraphy.

A group of 26 patients aged 47-81 years (average 67) with spinal osteoporosis and back pain for more than 6 months were investigated with planar and S...
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