Soft- tissue foreign bodies: Diagnosis and removal under ultrasound guidance
Gustavo Figueredo Casadei MD,Karina Romero MD, and Victor Gomez MD
Department of Radiology, CooperativaMédica de Rocha. Montevideo. Uruguay.
ABSTRACT
Soft tissue foreign bodies due to penetrating injuries are a common reason for emergency department visits.
We present a series of six cases in which ultrasound was used successfully not only as a diagnostic tool but also as a real-time guidance for their removal.
Key words: ultrasound, sonography, foreign body, penetrating wounds.
Contact- e-mail: [email protected]
OBJECTIVES due to vegetal material (thorns) and lesser to metal and glass fragments. This paper aims to fulfill two objectives; firstly to demonstrate the A FB undetected, can be a source of utility of diagnostic ultrasound in the complications and malpractice detection and characterization of lawsuits (5) foreign bodies (FB) retained in soft tissues, and secondly to demonstrate Traditionally, and as the first imaging the usefulness of ultrasound in their modality for the initial workup,radiography of the area is removal, allowing realtimecontrol maneuver. It also highlights the fact done, which primarily shows that ultrasound is the imaging method radiopaque objects. For several years of choice when retained FB are ultrasound has been positioned as the clinically suspected. first diagnostic method to visualize all types of FB, providing removal INTRODUCTION guidance.
FB retained in soft tissue are a This article shows a series of patients common cause of consultation in with soft tissues FB in extremities, in adults and children (1,2,3,4), usually which ultrasound was successful both in detection and removal. Soft- tissue foreign bodies: Diagnosis and removal under ultrasound guidance
MATERIALS AND METHODS MHz) linear transducers in two units (General Electric and Esaotemodel The sample included 6 patients, My Lab 50). studied between March and September 2011. RESULTS
The age ranges between 5 and 65 Case 1- years, being 4 male and 2 female. 66 -year -old patient with a 15 day Patients were referred by surgeons history of penetrating injury in foot for suspected FB from penetrating plant, while swimming in a river. The wounds, in all cases with an evolution patient does not know the nature of of more than 10 days and less than the traumatic agent. two months. Retained FB is suspected. An X Ray In five cases the agent, of organic is performed, which shows no origin was suspected (plant thorn) abnormality. Given the persistence of while it was unknown on a foot injury pain, ultrasound is performed case. The symptoms in all cases were confirming a 32mm long FB. persistent pain in the affected area, Consulting plastic surgeon suggested even after the disappearance of the removal under ultrasound guidance. puncture wound. In a patient with a The procedure was performed forearm injury, there was also through the primary traumatic point of significant edema and soft tissue entry, obtaining vegetable thorn. infection, and signs suggestive of deficient ulnar nerve involvement. Favorable evolution ,without complications. Figures Case 1 In three cases the wounds were Case 2- located in the upper limbs, and the remaining in feet. 55 -year -old female, with a 15 day In one case there had been previous history of penetrating injury in her conventional surgery without FB right forearm by palm thorn.Post- localization. traumatic event, radiograph was obtained showing no evidence of FB Four cases underwent radiograph of 24 hours later she begins with soft the area, being negative. The other tissue edema of the affected area, two cases were studied only with and fever. ultrasound. Partial response to antibiotics. Ultrasonographic studies were performed using high frecuency (8-12 Consultation with plastic surgeon was done.
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The requesting ultrasound study FB is suspected with clinical palpation showed negative results. Afterwards and is operated 10 days after. she installs deficit signs of ulnar nerve, whereupon the surgeon Conventional surgery cannot find the requests new ultrasound, confirming FB, and given the persistence of the presence of FB. Removal of the symptoms (pain) an ultrasoundstudy FB is performed under ultrasound- is performed. guided. Regresion of deficient ulnar Ultrasound confirms FB, 10mm long, afectation as well as the infection without reverberation phenomena, were atteined. probably vegetable FB. Given the age Figures Case2 of the patient, general anesthesia is performed and FB is extracted with Case 3- ultrasound guidance without complications. Figures Case 3 8- year- old girl with a 25 days history of penetrating wound in right or left foot.
Soft- tissue foreign bodies: Diagnosis and removal under ultrasound guidance
Case 4- Case 5-
5-year-old boy, with a 12 day history 48-year-old male who works at a of penetrating injury in dorsum of foot. sawmill. 15 days before the consultation suffered a puncture As pain continued, ultrasound was wound in the left palm hand performed confirming the presence of (hypothenar) with a wood splinter. A an 8mm FB at the clinical problem radiograph was performed. It showed area. Due to the inconsistency no abnormalities. Given the between the transducer size and persistence of pain in emergency localization, which made not possible consultation, an ultrasound was the removal with ultrasound performed confirming the presence of guidance,she has an intervention a FB. An ultrasound-guided under general anesthesia. It is not procedure was performed. A wood possible to extract the FB by splinter larger than 15mm was ultrasound, so skin is marked on the removed. location and removed with conventional surgery. He progressed favorably.
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Case 6- All patients recovered favorably with pain remission, even in the case of 51-year -old male. While pruning a the patient with ulnar compromise tree suffers a palm penetrating wound (Case 2), in which the referred motor in his right hand, on the basis of the deficit remitted with the FB removal. fifth finger. Radiographis obtained from the affected area showed no FB DISCUSSION images. Ultrasonography was performed confirming FB. Ultrasound- FB held in soft tissues from guided procedure is carried on, with penetrating injuries are common the removal of a 12 mm wood causes of consultation in emergency splinter. Progressed favorably. services. They are also considered as the second leading cause of emergency medical lawsuits.
In 4 patients XRays were performed, A FB that has not been removed, can they failed to show evidence of FB, lead to both acute and chronic even in a case of a bulky one. complications such as allergies, inflammation and infection.(1,2,3,6,7). Figures Case 1 If FB is close to tendons they may Ultrasonography was diagnostic in all cause tenosynovitis, and in case of cases. nerves neuropathies, as it occurred in one patient in this study. There may Clinical examination was unable to also be migration to joints causing make the diagnosis in all cases. arthropathies and embolic complications due to access to the In 5 patients the FB was successfully venous system. (1) removed under ultrasound guidance by the sonographer itself, as According to the evolutionof the discussed in case 4, given the injury, the condition may be classified inconsistency between the transducer in stages: and the affected area the removal was not possible, so the FB 1) Acute: less than 3 days. localization is marked on the skin and 2) Intermediate: 3 to 10 days. removed with conventional surgery. 3) Chronic: more than 10 days. (5) In all cases the vegetable thorn was obtained and visualized as linear or The sonographic appearance of FB is cuneiform echogenic structures related to the evolution time. surrounded by a hypoechoic rim with faint shadow cones. The sizes varied In our series, all patients were in between 8mm and 30mm. chronic stage. Soft- tissue foreign bodies: Diagnosis and removal under ultrasound guidance
The economic cost of FB extraction rare condition, taken in a short period with sonography is significantly lower of time, with a sample taken from a than that of small conventional single geographic region, and carried surgery, even in the case of children on by a single operator. Another requiring general anesthesia. There limitation is that all the FB diagnosed are very significant benefits in were vegetable origin, so experience shortening the surgery act Moreover, with other materials is lacking in this an ultrasound guided failed removal study. does not exclude conventional CONCLUSIONS surgery.
At our institution, there is agreement For suspected FB, the first imaging with the surgeons that the method to be performed must be sonographer tries at first instance and sonography which allows diagnosis, by himself the FB removal. interventional procedure removal, with great advantages for the patient. A critique of this study may be the low number of patients in this series, although it should be noted that it is a
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APPENDIX Simple radiograph is the initial study when a FB is suspected is simple Soft-tissue foreign bodies: diagnosis radiograph of the region since it is and removal technique under widely available and has low cost ultrasound guidance. (2,4,5,6,7)
The FB can be divided in two groups Metal objects with high atomic weight, according to their composition: that stop photons (radio-opaque) are a) Metallic most easily detected by this method. These materials such as glass, metal b) Organic and stones, are detected up to 80% of the cases. c) Inorganic The radiopaque FB as plastic or The metallic consist of any material glass, are visible in radiograph only in with high atomic number, therefore 15% of the cases. (1,3,4,5,6) they have the ability to stop the photons, and can be easily visible in In our experience in 4 cases conventional radiology (1,2,5,6,7) radiograph wasnegative, including a 32 mm long thorn located in plantar The organic are referred to the foot. organic material of vegetal origin, such as wood splinters, vegetable 1) Radioscopy thorns, etc. As simple radiograph, radioscopy The inorganic materials come from shows radiopaque objects. When it is not living beings, such as broken possible to identify the FB, glass, plastics, rubber, etc. fluoroscopy provides an adequate topographical idea, allowing skin A) Diagnosis marking on the reference points for When a retained FB is suspected , removal. (1, 2) However it exposes the first method is clinical examination the operator and patient to high doses which is positive only when the FB is of radiation. (1,2,7) in superficial tissues and can be 2) Ultrasound palpable. This occurs in a very small number of patients, so in the vast The use of ultrasound in detecting FB majority of cases, imaging tests are began in 1978, since then it became needed to confirm the presence and an excellent alternative in detecting localization overlooking the removal. FB, besides providing three- dimensional information, and FB As previously mentioned, clinical relationship with relevant soft tissue examination was unsuccessful in all cases of this study. Soft- tissue foreign bodies: Diagnosis and removal under ultrasound guidance structures, such as muscles, tendons, The sonographic appearance of vessels, nerves, etc.(1,2,3,4,5,6,7) organic FB also varies taking into account the evolution time. 1.2.5.6 The development of high-frequency transducers, up to 12 MHz, has In the acute phase (up to 3 days after improved spatial resolution, achieving injury) the FB has a bright anatomic detail of small structures echogenicity with posterior acoustic with high accuracy and may identify shadowing well marked. This is FB under 1mm in diameter. mainly due to the air that is trapped Ultrasound is currently the imaging within the material. method of choice, with a sensitivity of 90% and a specificity of 96%.(1.2) At the end of this stage, there may be a hypoechoic rim surrounding the FB. For proper technique, requires a slow It has been thought to be due to and meticulous examination, edema, pus or granulation especially in cases of small FB less phenomena. In the intermediate stage than 1cm in length, where they can be (3 to 10 days) the halo becomes more unnoticed, also in anatomical areas marked, and the echogenicity of the like hands and feet, where echogenic material decreases, while the shadow structures exists such as sesamoid cone becomes less defined. bones that can result in false positives. In the chronic stage (after 10 days) a dense granulation tissue Another aspect to consider is that encapsulates the FB. 5 In almost all echogenicity of a FB also varies cases of this study, hypoechoic halo according to the orientation of the was present, which showed the long axis FB with respect to the skin. chronicity of the process, and When the FB is parallel to the skin the facilitated the identification of the FB, visualization is maximum. Moreover it especially the smaller ones. should be noted that small punctate structures may correspond to bulky Ultrasound has the disadvantage of FB if the cutting plane was carried by being an operator-dependent method, the short axis, as for example in the and hence with variable results case of thorns. according to the experience of the operator. It has been described that the size of the FB contributes most to the Another limiting factor of the method detection than the composition. 2 is the depth at which the FB is located .2.5
While a small object of 5mm can be easily identified when superficial,
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bigger FB may not be detected in 1) ultrasound equipment 2) aseptic deeper areas. matherial, syringes, scalpel, sterile drapes, gauze etc. 3) small forceps or The air trapped within a penetrating mosquito clamp. 1.5.8.9 wound, may also create false positives, when producing images High frequency transducers are that mimic echogenic FB, or also hide needed, usually between 8 and them.2.5 12MHz to achieve higher image quality in superficial structures. 3)Computed Tomography (CT) Linear transducers are generally It can also be used in the detection of used, although in some situations and foreign bodies. Against is its high narrow anatomic places which leads cost, limited availability, and high to difficult anatomical approach,it may irradiation. In case of children may be useful small convex transducers to also require general anesthesia. 1.5.7 suit any surface. Transducer should be covered with sterile (gloves), and proceed skin disinfection.
The techniques used are "free hand" in which the same operator maneuver 4) MRI with one hand the transducer (not It can also be used, although given skillful hand) and with the other hand it’s high cost makes it prohibitive as a (skilled) manipulates the instruments routine method. Both CT and MRI and long axis technique .1.8 have low sensitivity and specificity. Once located the FB is displayed in 1.5.7 its entire length. B) Description of the procedure. Using the long axis of the transducer, Extraction of ultrasound-guided FB is and close to it, the skin is infiltrated a good alternative to conventional with 1% lidocaine and the way to the surgery, because it is safe, FB, trying to reaching it, and creating inexpensive, and with low a "collection" around it. Besides the complication rates. On the other anesthetic effect, it facilitates the hand, if it fails, it does not exclude visualization and subsequent conventional surgery.1.4.5 maneuvers for the removal. In case of children, such as in small Once located the FB and been conventional surgery, general decided its removal under ultrasound anesthesia is always required, which guidance the elements prepared to allows to work accurately without use are: inconveniences. Soft- tissue foreign bodies: Diagnosis and removal under ultrasound guidance
The needle is removed and it is be used as the preferred way to necessary to wait for the local withdraw the FB, and proceed in a anesthetic to take effect. In the similar way as related previously.1.5. puncture site, an incision is made in the skin, with a small scalpel blade In this series no prophylactic (number 11) creating a path to the antibiotics were used, although some FB, always in real-time visualization. authors routinely indicate them. 1 It must ensure that the scalpel tip This procedure requires some manual reaches the FB, and this incision is dexterity, but the learning curve can also wide enough to enter and be shortened with practice in allowing the manipulation forceps biological models such as chicken or therewith. turkey. 1.8.
The operator proceeds then to As for conventional surgical introduce the forceps, and through management of FB, it can be said that real-time control, the extraction of FB. there are two groups, one with large (1.5.8.10) open wounds such as scalping or The correct way to hold the FB, is to attritioning tissue, and one with small bring the forceps closed until its inlets. In the first group, it requires a contact with the FB, and gently open thorough examination to rule out it and then move it forward a few neurovascular injuries, tendons, etc., millimeters. (10) and this exploration also allows the simultaneous search of FB. If the forceps is opened prior to "touch" the FB,it is likely that the Even if no neurovascular or tendinous procedure is unsuccessful because structures injury exists, it requires soft tissues "are clamped" instead of extensive dissection to allow correct FB search. the FB. It should also be secured to one end the FB, allowing the In case of small FB with minimal entry extraction through the longitudinal into skin, conventional surgery is path created. (10) usually avoided because of the risk of Once the procedure is finished, a cure injury, and the difficulty in finding the is done with sterile equipment. FB in the operative field, both because of bleeding and the variable Usually stitches to close the wound are not required. appearances of FB. (1)
On the other hand, if wound on the Extraction with ultrasound guidance skin corresponding to the inlet port of reduces the amount of bleeding and the traumatic event exists, it should prevents damage to nearby relevant structures to the FB. Using small
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instruments, an excellent cosmetic J Ultrasound Med 2003, 22:1381- result is achieved. (1) 1385.
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