European Journal of Ultrasound 6 (1997) 111–116

Clinical report

The benefit of ultrasound in lesions of the pubic symphysis1

Klaus Weber a,*, Andreas Mahlfeld b, Carsten Sekulla a, Wieland Otto b

a Department of General Surgery, Martin-Luther-Uni6ersitat Halle-Wittenberg School of Medicine, Ernst-Grube-Str. 40,D-06097 Halle/S, Germany

b Department of Traumatology and Rekonstructi6e Surgery, Martin-Luther-Uni6ersitat Halle-Wittenberg School of Medicine,Ernst-Grube-Str. 40, D-06097 Halle/S, Germany

Received 18 October 1996; received in revised form 28 April 1997; accepted 15 May 1997

Abstract

The purpose of this study was to compare the results of measurement of the pubic symphysis taken by ultrasoundand X-ray pictures. From January to December 1994 ultrasonography of the pubic symphysis was performed by twoexaminers on 50 healthy people and 21 patients with lesions of the symphysis. The measurements of diastasis as wellas of vertical dislocation of the pubic symphysis taken by ultrasound were comparable to the X-ray picture with ahigh statistical significance. The inter- and intra-observer variability was B2 mm. Ultrasonic investigation besidesstandard methods is useful for primary diagnosis and follow-up examination in injuries of the symphysis area.Accompanying fractures of the posterior pelvic ring stay, in this case, undetected. © 1997 Elsevier Science IrelandLtd.

Keywords: Ultrasound; Pubic symphysis lesion; Primary diagnosis; Follow-up examination

1. Introduction

Lesions of the pubic symphysis are usually di-agnosed by pelvic X-rays. The use of ultrasound

examination as a diagnostic tool is, at present,uncommon. A routine use of ultrasound for diag-nosis and follow-up examination of bone fracturesis reported only in infant traumatology. The otherknown diagnostic use of ultrasound in bone mea-surements is in obstetrics when it is used for theprimary diagnosis and control of postpartumwidening of the pubic symphysis (Bahlmann et al.,1993; Huppertz et al., 1990).

* Corresponding author. Tel.: +49 345 5572095; fax: +49345 5572551.

1 Presented at the Second Congress of the European Federa-tion of National Association of Orthopaedics and Traumatol-ogy (EFORT) Munich, Germany, July 4–7, 1995.

0929-8266/97/$17.00 © 1997 Elsevier Science Ireland Ltd. All rights reserved.

PII S0929 -8266 (97 )10005 -2

K. Weber et al. / European Journal of Ultrasound 6 (1997) 111–116112

Fig. 1. Transducer position on patient’s symphysis.

In the early 1970’s, Abendschein and Hyattdescribed ultrasonics and selectete physical prop-erties of bone (Abendschein and Hyatt, 1970).Research for diagnosing fractures were performedby other authors. Because of the ease of applica-tion of the ultrasonic head, the tibia was chosenfor measurement of the velocity of ultrasound inhuman cortical bone in most of these cases(Gramlich et al., 1978; Greenfield et al., 1981).

The aim of our work was to find a standardmethod of ultrasound examination of the pubicsymphysis in healthy people and to use thisknowledge and statistical information in diagnos-ing and follow-up of symphysis lesions (Weber etal., 1996).

2. Patients and methods

From January to December 1994, we per-formed ultrasonography of the pubic symphysison 50 healthy people at the Martin-Luther-Uni-versity of Halle-Wittenberg. There were 25 maleand 25 female subjects and the age range was20–67 years. The examination was done by twoexaminers. In addition, sonography was used forprimary diagnosis (6 men, aged from 35 to 57years), postoperative check up and for follow-up

examinations (11 men, 4 women, aged 16–57years) of symphysis lesions along side conven-tional radiology since January 1994. The measure-ments of dehiscence as well as of verticaldislocation of the pubic symphysis taken by ultra-sound were compared to the X-ray findings.

2.1. Technique

The examination was performed with a 5.0 or7.5 MHz linear array transducer. The patient wasplaced in a horizontal position. For specific ques-tions (diastasis under weight bearing) it can alsobe of advantage to examine in one or two leggedfoot-stand.

The transducer has to be applied in the trans-verse plane in the suprasymphysis area and movedcaudally until bone structures are detected. Withthe ultrasonic head tipping over in angles between30–45° in the transverse plane, the best view ofthe symphysis pubic can be reached easily (Fig. 1).

2.2. Ultrasonographic anatomy

Right and left superior pubic rami are pre-sented as echogenic structures. The pubic symphy-sis is shown as an echolucency between the twopubic rami. The measured distance between both

K. Weber et al. / European Journal of Ultrasound 6 (1997) 111–116 113

Fig. 2. Ultrasonographic anatomy of the pelvic symphysis: 1,rectus abdominus muscle; 2, pubic ramus; 3, symphysis.

out a vertical dislocation in the anterior pelvicring. Six patients were primarily diagnosed byultrasonography and by AP pelvis X-ray. Themeasurements of the symphysis diastasis between9–23 mm taken by ultrasound were comparableto the results found on standard X-rays. Fifteenpatients of which seven were treated by plateosteosynthesis, two by external fixation and sixhad conservative management, underwent follow-up ultrasonic examination almost two years afterdischarge. Diastasis of the symphysis between 3–24 mm and vertical dislocation of the anteriorpelvic ring with the maximum height of 14 mmwere presented. The results of the examinationunder weight bearing (in standing position)showed no difference. The X-ray pictures confi-rmed these results. Only in two cases with verticaldislocation of 1.7 and 1.9 cm (diastasis of thesymphysis 21 and 23 mm) differences of almost 8mm between ultrasound and X-ray measurementwere detected.

In our research the inter-observer variability fordiastasis was under 0.2 mm, both in the controlgroup (standard deviation 0.08 mm; correlationcoefficient 0.99) and in the patients group. The

pubic rami shows the diastasis of the symphysis.Depending on age, 3–7 mm dehiscence variabilitywithout any vertical dislocation represents nor-mality (Figs. 2–4).

On X-rays the diastasis is taken by just measur-ing the distance of both superior pubic rami (Figs.5 and 6).

3. Results

The results of 50 healthy people showed adiastasis of the symphysis between 3–7 mm with-

Fig. 3. Measured distance betweeen both pubic rami (NAD).

K. Weber et al. / European Journal of Ultrasound 6 (1997) 111–116114

Fig. 4. Pelvic X-ray (same Patient)

Fig. 5. Sonography; rupture of the symphysis.

variability between ultrasound and X-ray waslower than 1 mm in the control group (S.D. 0.44

mm; correlation coefficient \0.9) and in the pa-tients group (S.D. 0.39 mm) (Tables 1 and 2).

K. Weber et al. / European Journal of Ultrasound 6 (1997) 111–116 115

Fig. 6. Pelvic X-ray (same Patient).

4. Discussion

Ultrasound investigation has proven to us to bea good addition to radiology, both in primarydiagnosis and follow-up examination, but cannotreplace it. Ultrasound has the advantage, com-pared to normal X-rays, in that it can be carriedout and performed on any ward or at the emer-gency room. Its convenience and the fact that itdoes not cause any radiation side effects to thepatient is superior.

Sonographical signs of a damaged pubic sym-

physis are a deviation of widening (Bahlmann etal., 1993; Huppertz et al., 1990) and height varia-tion. In our research, the measured results of thesonographic examinations are clinically and statis-ticaly comparable to the X-ray pictures (correla-tion coefficient \0.9) with a interobservervariability under 0.2 mm (Bland and Altmann,1986).

Follow-up examination in patients with exter-nal fixation is easier to perform by ultrasound ascompared to X-rays since the overlapping ofmetallic construction can often cause disturbancein the radiological picture.

Table 1Average and S.D. of the ‘absolute difference’ between ultra-sound and X-ray (control-group)

Control-group

Sono-obs 2bAverage (S.D.) mm Sono-obs 1a

0.12 (0.08) —Sono-obs 2X-ray 0.69 (0.44)0.70 (0.43)

aSono-obs 1: sonography observer 1.bSono-obs 2: sonography observer 2.

Table 2Average and S.D. of the ‘absolute difference’ between ultra-sound and X-ray (patient-group)

Patients-group

Sono-obs 1aAverage (S.D.) mm Sono-obs 2b

0.13 (0.07)Sono-obs 2 —X-ray 0.58 (0.38)0.55 (0.39)

aSono-obs 1: sonography observer 1.bSono-obs 2: sonography observer 2.

K. Weber et al. / European Journal of Ultrasound 6 (1997) 111–116116

Our experience in sonographic diagnosis ofsymphysis lesions are restricted to the number ofpositive cases diagnosed. Routine use of the ultra-sound investigation aside from the standard radi-ological methods can be recommended forprimary diagnosis, postoperative checks and fol-low-up examination. Accompanying fractures ofthe dorsal pelvic ring stay in this case undetected.

References

Abendschein W, Hyatt GW. Ultrasonics and selectete physicalproperties of bone. Clin Orthop 1970;69:294–301.

Bahlmann F, et al. Sonographische Darstellung des Symphy-senspaltes zur Beurteilung eines Symphysenschadens in derSchwangerschaft und post partum. Z Geburtshilfe Perina-tol 1993;197:27–30.

Bland JM, Altmann DG. Statistical methods for assessingagreement between two methods of clinical measurement.Lancet 1986;8:307–10.

Gramlich B, et al. Zur Beurteilung des Knochenzustandes mitUltraschall. Z Exp Chir 1978;11:258–61.

Greenfield MA, et al. Measurement of the velocity of ultra-sound in human cortical bone in vivo. Radiat Phys1981;2:702–10.

Huppertz R, et al. Symphysensprengung—klinische und sono-graphische Verlaufskontrolle. Z Orthop 1990;128:32–3.

Weber K, et al. Stellenwert der Ultraschalluntersuchung beiVerletzungen der Symphyse. Unfallchirurgie 1996;1:36–8.

..