Effect of sympathetic block demonstrated by triple-phase bone scan

Effect of sympathetic block demonstrated by triple-phase bone scan

Effect of Sympathetic Block Demonstrated by Triple-phase Bone Scan Joan Hoffman, RN, MSN, William Phillips, MD, Maria Blum, MD, Richard Barohn, MD, So...

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Effect of Sympathetic Block Demonstrated by Triple-phase Bone Scan Joan Hoffman, RN, MSN, William Phillips, MD, Maria Blum, MD, Richard Barohn, MD, Somayaji Ramamurthy, MD, San Antonio, TX The triple-phase although

bone scan is frequently

the etiology

the effect

of increased

In 15 reflex

scan.

of the abnormal blood

flow

sympathetic

sympathetic

block,

baseline

a significant

linear

relationship

block

on the blood

counts

increased,

inspection flow

pool

secondary

dystrophy

patients,

between

change

image and bone uptake of typical

These results

as the cause of increased

periarticular

From the Departments of Anesthesiology, Radiology, and Medicine, University of Texas Health Science at San Antonio, San Antonio, TX. Received for publication Dec. 15, 1992; accepted in revised form April 12, 1993. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Joan Hoffman, RN, MSN, Department of Anesthesiology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78284-7838. The Journal

of Hand

Surgery

block

all of whom

block image.

from

had significant baseline

evaluated relief

bone with

There was

to postsympathetic

pool and bone uptake

dystrophy

the concept

(J Hand

dystrophy

on the triple-phase

As the blood

sympathetic support

uptake.

This study

bone scans were analyzed.

in counts

reflex

strongly

of reflex sympathetic

established.

to sympathetic

The triple-phase bone scan is frequently used in the diagnosis of reflex sympathetic dystrophy (RSD). Clinical symptoms of RSD such as burning pain, allodynia, edema, vasomotor changes and sweating, and color differences vary widely among patients, whereas the triple-phase bone scan has been reported to be very sensitive (60-100%) and specific (8O-97%).‘-4 The triple-phase bone scan involves the intravenous injection of a bone-seeking radionuclide. In the first phase serial images demonstrate arterial blood flow. The second phase, called a blood pool image, reveals the vascular and extracellular radionuclide. Two to 4 hours after injection the third phase, or bone uptake phase, is performed. In RSD the findings on the bone scan include a difference in blood flow and blood pool when com-

860

is not well

and postsympathetic

the likelihood

also increased.

used in the diagnosis findings

findings

of increased

on visual vascular

Surg 1993;18A:860-864.)

pared to contralateral extremity and diffusely increased periarticular tracer activity in the bone uptake phase. The etiology of these findings is not well established. Increased bone blood flow that causes increased bone uptake5 has been postulated by several authors to be the cause for the typical periarticular findings in RSD in the bone uptake phase,‘v6 although bone uptake could be influenced by other factors including hormonal and metabolic factors.‘,’ The present study was designed to determine the effect of increased blood flow secondary to sympathetic block on the triple-phase bone scan in patients with RSD. Materials

and Methods

After approval by the Institutional Review Board, 15 patients diagnosed with RSD of an upper extremity based on clinical symptoms consented to be in this study. All patients enrolled in this study had undergone a recent triple-phase bone scan (3-7 days previously). Only patients who experienced more than 50% pain relief following stellate ganglion block were included. The stellate ganglion block was performed using 10 mL of 0.5% bupivacaine. When onset of sympathetic block was confirmed clinically (30 minutes to 1 hour after block), the triple-phase

The Journal of

bone scan was repeated. The presence of sympathetic block was confirmed by the presence of Horner syndrome and an increase in skin temperature in the hand without motor or sensory changes. Visual analog pain scales (O-IO) were recorded before and after block. Surface skin temperatures were recorded prior to each bone scan in three sites (tip of index finger and over the palmar surface in the webs between the first and second metacarpal joints and between the fourth and fifth metacarpal joints). The triple-phase bone scans were done using technetium-99m-methylene diphosphonate (99mTcMDP) according to protocol in this institution. A butterfly or small gauge intravenous catheter was inserted in the antecubital space. The injection was delayed at least 5 minutes after tourniquet release to minimize the influence of reflex hyperemia.’ Dynamic images were taken every 2 seconds for 2 minutes followed by a 5-minute blood pool image. Delayed bone uptake images were taken 3 hours following injection. Blood pool and bone uptake images were acquired and analyzed using the Medasys Computer (Ann Arbor, MI). Quantitation of equally sized regions of interest (right and left hands distal to the radial styloid process) was performed on the dynamic S-minute blood pool images and delayed 3-hour bone uptake images. Numbers are expressed in percent of radioisotope detected in the affected extremity when compared to the total

Figure 1.

Baseline scan: patient 8. (A)

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Surgery / Vol.

18A No. 5 September

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861

counts in both extremities. Films were interpreted in a blinded manner by a nuclear medicine physician. Scans were rated as definite RSD (2+), suggestive of RSD (I + 1, or no evidence of RSD (0) based on the presence of typical RSD findings. Blood pool and bone uptake counts were analyzed for baseline and postblock scans. Changes in percent blood pool to bone uptake before to after block were analyzed using Pearson’s correlation coefficient. Baseline scan blood pool counts were correlated with duration of symptoms. The blood pool for all scans (baseline and postblock) was correlated with bone uptake. with ratings by the nuclear medicine physician, and with temperature difference (average temperature in “C of affected extremity - normal extremity). Since subjects were measured two times a repeated measures analysis was needed. Partial correlations between blood pool and the three measures of bone uptake, temperature, and ratings were analyzed for three different situations. These were used to determine the significance of the correlation between subjects adjusted for time differences, between times adjusted for subject differences. and within both subjects and times. A partial correlatioti was used since it adjusts for another variable by holding it constant or adjusting for differences due to the third variable when computing the correlation of the first two.

Blood

pool

image.

(B) Bone uptake.

862

Hoffman

et al. / Triple-phase

Bone Scan and Effect of Sympathetic

Block

Results Ten women and 5 men with symptoms from 1 to 44 months (mean, 11 -+ 11.7 months) were enrolled in this study. Seven patients were classified as stage I RSD and eight as stage II, based on clinical criteria. No stage III patients are included since these patients typically do not respond to sympathetic blocks. Overall, scans tended to become more suggestive of RSD postsympathetic block. Baseline bone scans in seven patients were not suggestive of RSD, although in three of these patients postblock scans were read as definite RSD. In patient 8, for example, the baseline bone scan was negative (Fig. 1) while the postsympathetic block was read as definite RSD (Fig. 2). There was a significant linear relationship between change (baseline compared to postsympathetic block) in counts on the blood pool image (BlP) and bone uptake image (BoU). As the blood pool counts increased, the bone uptake increased by approximately 60% (Fig. 3). The equation that describes this relationship is BoU = .586899 + S86014 x BlP (r = .985, p = .OOl). The relation of all counts for blood pool to bone uptake (both baseline and postblock) showed a significant and very strong correlation of blood pool and bone uptake between subjects (r = .948, p = .OOOl), between times (Y = .990, p = .OOOl); and within subjects and times (r = .984, p = .OOOl).

-10-l -10

-5

0

5

10

15

20 25 Change in Blood Pool (?G)

30

35

, 40

Figure 3. Change in blood pool and bone uptake following sympathetic block compared to baseline.

This indicates a clear consistent linear relationship between blood pool and bone uptake as seen in Figure 4. Figure 4 also demonstrates the correlation of the independent reading by a nuclear medicine physician showing that lower counts on blood pool were associated with negative readings, and as the count increased, readings progressed to suggestive and then definite. This correlation was significant and strong between subjects (r = .813, p = .OOOl), between times (r = .928, p = .OOOl), and within subjects and times (r = .861, p = .0003).

Figure 2. Postsympathetic block scan: patient 8. (A) Blood pool image. (B) Bone uptake.

The Journal

.

’ MD

40; 40

50

60

70

60

90

Blood Pool (%)

of bone uptake to blood pool for all bone scans (baseline and postsympathetic block) showing visual reading of scans.

Figure 4. Correlation

The correlation of blood pool with temperature was moderate between times (r = .504, p = .137), smaller between subjects (Y = .323, p = .153), and small within subjects and times. Sample size was not sufficient to make these moderate correlations significant, although there is evidence of a trend (Fig. 5). Discussion This study indicates a definite relationship between an increase in blood flow as evidenced in the blood pool activity and an increase in bony uptake activity. As the blood pool count and bone uptake count increase, so does the likelihood of typical RSD changes on visual inspection of the triple-phase bone scan. These findings strongly support the concept of increased vascular flow as the cause of in-

100 1

01 -6

-2

-4

0

2

4

6

0

Difference in Skin Temperature (“C)

Figure 5. Correlation

perature (symptomatic

of blood pool to difference - asymptomatic hand).

in tem-

of Hand

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creased periarticular uptake. Ironically, a stellate ganglion block that relieves the patient’s symptoms of pain and allodynia intensifies the typical findings on the triple-phase bone scan. Our findings are largely in agreement with previous findings in animal models that demonstrated the correlation of blood flow and uptake of radiopharmaceuticals.‘O,l’ The typical periarticular uptake in RSD appears to correspond with the epiphyseal arterial system of the bone.” The correlation of the typical RSD changes with increased blood pool activity previously has not been clearly documented. Skin temperatures that are widely used to diagnose patients with RSD and evaluate their response to treatment tend to correlate with the blood pool activity, although this was not statistically signiticant. Some of the variance in this correlation could be due to the fact that skin temperature reflects mainly skin blood flow while blood pool also reflects flow to deeper tissues including muscle and bone. Skin temperature is also influenced by room temperature and other environmental factors. Patients with RSD reportedly progress through three stages. In the first (acute) stage the affected limb is initially described as warm and red. Toward the end of this first stage the skin becomes cold and cyanotic as described in later stages. ” Clinically we find great variation among patients who do not fit neatly into the stages described but often vacillate between cooler and warmer skin temperatures from day to day and even one minute to the next. During the early hyperemic stage of RSD positive findings on the bone scan would be expected. No correlation between positive scans and duration of symptoms was found in this study, probably due to our small sample size and the variation among patients in their time course through each stage. While some authors have used the triple-phase bone scan to monitor response to treatment, I4 our findings indicate that the bone scan may normalize over time even without treatment as the patient progresses to the second and third stages of RSD. This change over time was demonstrated by Demangeat et al..” although individual cases did not always fit this pattern. Also, treatments that interrupt the sympathetic tone and increase blood flow also intensify the positive findings on triple-phase bone scan, thus patients with pain relief demonstrate positive scans. at least in the short-term follow-up period as demonstrated in this study. Our findings strongly support the concept of increased vascular flow as the cause of increased periarticular uptake. If this is the case, the triple-phase bone scan is useful in diagnosing RSD in the early hyperemic phases. Its usefulness in diagnosing RSD

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et al. / Triple-phase

Bone Scan and Effect of Sympathetic

in later stages or in following a patient’s response to treatment is questionable. Further prospective controlled studies are needed to establish the usefulness of bone scans in diagnostic and long-term follow-up evaluation.

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7. Shim SS. Physiology of blood circulation of bone. J Bone Joint Surg 1968;50A:812-24. 8. Dye SF, Boll DA. Radionuclide imaging of the patellofemoral joint in young adults with anterior knee pain. Orthop Clin North Am 1986;17:249-62. 9. Desai A, Intenzo C. The tourniquet effect. J Nucl Med 1984;25:697-9. 10. Siegel BA, Donovan RL, Alderson PO, Mack GR. Skeletal uptake of 99mTc Diphosphonate in relation to local bone blood flow. Radiology 1976;120:121-3. 11. Genant HK, Bautovich GJ, Singh M, Lathrop KA, Harper PV. Bone seeking radionuclides: an in vivo study of factors affecting skeletal uptake. Radiology 1974;113:373-82. 12. Allman RM, Brower AC. Circulatory patterns of deossification. Radio1 Clin North Am 1981;19:553-69. 13. Bonica J. Causalgia and other reflex sympathetic dystrophies. In: Bonica J (ed), The management of pain. 2nd ed. Malvem, PA: Lea & Febiger, 1990:232-3. 14. Kozin F, Genant HK, Bekerman C, McCarty DJ. The reflex sympathetic dystrophy syndrome: II. roentgenographic and scintigraphic evidence of bilaterality and of periarticular accentuation. Am J Med 1976;60: 332-8. 15. Demangeat JL, Constantinesco A, Brunot B, Foucher G, Farcot JM. Three-phase bone scanning in reflex sympathetic dystrophy of the hand. J Nucl Med 1988; 29:26-32.