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Detection of a 0.5-mm-thick thorn using ultrasound: A case report
Detection of a 0.5-mm-thick Thorn Using Ultrasound: A Case Report Joseph M. Failla, MD, Marnix van Holsbeeck, MD, Geert Vanderschueren, MD, Detroit, MI
A 41-year-old, right-handed woman presented with thumb pulp swelling of 48 hours duration and increasing pain. The swelling had begun 1 day after she punctured the ungloved right thumb pulp with a thorn as she was trimming roses. Physical examination showed a firmly swollen, red, tender, and warm thumb pulp. Thumb interphalangeal joint flexion was slightly limited by pain but no pain was present over the flexor sheath. X-ray films showed soft tissue swelling but no foreign body or bone changes. The patient was treated for felon by incision and drainage, oral cephalosporin, and soaks. Cultures grew Staphylococcus aureus; a fungal stain was negative. The wound remained inflamed, and a retained thorn was suspected. A computed tomography (CT) scan was contemplated, but ultrasound examination was chosen to rule out a thorn in the thumb pulp. A 10-MH linear array transducer was used (Acoustic Imaging, Phoenix, AZ). Ultrasound examination revealed a .5 mm object anterior to the distal phalanx in the depths of the thumb pulp radially (Fig. 1). The patient was taken to the operating room where the thorn was located using the ultrasound probe placed in a sterile plastic bag. A linear incision down to the distal phalanx palmar radial cortex was made under 3.5-1oupe magnification. Small amounts of inflamed and hem-
From the Department of Orthopaedic Surgery, Henry Ford Hospital, Detroit, MI. Received for publication Sept. 22, 1994; accepted in revised form Nov. 16, 1994. 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: Joseph M. Failla, MD, Henry Ford Hospital, Department of Orthopaedic Surgery, 2799 West Grand Boulevard, Detroit, MI 48202.
456
The Journal of Hand Surgery
orrhagic pulp fat were progressively spread and excised until a cream-colored, triangular, pointed foreign body was found. This was the tip of the suspected thorn and measured 1 mm in length, just less than 1 mm in width tapering to a point, and 0.5 mm in thickness. After the object was removed, a repeat intraoperative ultrasound revealed the foreign body was no longer present, confirming that the object removed was the one detected by the ultrasound. The patient's infection resolved after 48 additional hours of intravenous antibiotic therapy and 1 week of oral antibiotic therapy; all wounds healed. Final cultures were negative for sporotrichosis.
Discussion Ultrasound has been used clinically to locate wood in soft tissues of the extremity. Splinter fragments 4 cm long were found preoperatively in the foot in one case. 1 Ultrasound was also used to locate a 6-ram long and 1-mm wide hollow glass pipette embedded within the flexor pollicis longus tendon in another case. 2 The dimensions of the foreign bodies in these two cases were, however, much larger than the 0.5mm-thick thorn found in our patient. Additionally, in the case of the glass pipette, x-ray films did not reveal it. CT scan has been mentioned as the preferred method to detect wooden foreign bodies in the soft tissues of the hand. Resolution was found to be between 1 and 2 mm. 3 The thorn tip found in this patient, which was seen in profile of .5 mm thickness, likely would not have been seen on CT scan. Thorn is a plant material similar to wood, but less dense, and the ultrasound examination revealed it clearly. This suggests that the resolution of ultrasound is as good or perhaps greater than that of CT scan in detecting small wooden or woodlike foreign
The Journal of Hand Surgery / Vol. 20A No. 3 May 1995
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Figure 1. Longitudinal ultrasound view of the palmar radial portion of the thumb pulp. The thorn tip (arrow) is linear, hyperechoic compared to surrounding pulp, and visible anterior and parallel to the palmar cortex (*) of the distal phalanx (DP). In profile, it is seen to be 0.5 mm wide and is 1 mm long.
bodies in soft tissue. Ultrasound in this case was also crucial in locating the thorn and documenting removal o f it intraoperatively. The ability to use ultrasound in the operating room is another potential advantage over CT scan. Other advantages of ultrasound are the smaller cost compared to CT scan and lack o f radiation exposure. It may be that in some cases echogenicity of the foreign body is too similar to that o f the tissue in which it is embedded to allow detection. In such a case, an ultrasound examination would give a false negative result. However, the case reported here demonstrates that the resolution of ultrasound can be excellent. It is thus reasonable to use ultrasound examination to detect small wooden foreign bodies in the soft tis-
sue o f the hand if plain x-ray films are negative, and to reserve CT scan for cases where ultrasound examination is negative, thus increasing accuracy and reducing cost.
References 1. Kobs JK, Hansen AR, Keefe B. A retained wooden foreign body in the foot detected by ultrasonography. J Bone Joint Surg 1992;74A:296-8. 2. Levine WN, Leslie BM. The use of ultrasonography to detect a radiolucent foreign body in the hand: a case report. J Hand Surg 1993;18A:218-20. 3. Russell RC, Williamson DA, Sullivan JW, Suchy H, Suliman O. Detection of foreign bodies in the hand. J Hand Surg 1991;16A:2-11.
A 41-year-old, right-handed woman presented with thumb pulp swelling of 48 hours duration and increasing pain. The swelling had begun 1 day after she punctured the ungloved right thumb pulp with a thorn as she was trimming roses. Physical examination showed a firmly swollen, red, tender, and warm thumb pulp. Thumb interphalangeal joint flexion was slightly limited by pain but no pain was present over the flexor sheath. X-ray films showed soft tissue swelling but no foreign body or bone changes. The patient was treated for felon by incision and drainage, oral cephalosporin, and soaks. Cultures grew Staphylococcus aureus; a fungal stain was negative. The wound remained inflamed, and a retained thorn was suspected. A computed tomography (CT) scan was contemplated, but ultrasound examination was chosen to rule out a thorn in the thumb pulp. A 10-MH linear array transducer was used (Acoustic Imaging, Phoenix, AZ). Ultrasound examination revealed a .5 mm object anterior to the distal phalanx in the depths of the thumb pulp radially (Fig. 1). The patient was taken to the operating room where the thorn was located using the ultrasound probe placed in a sterile plastic bag. A linear incision down to the distal phalanx palmar radial cortex was made under 3.5-1oupe magnification. Small amounts of inflamed and hem-
From the Department of Orthopaedic Surgery, Henry Ford Hospital, Detroit, MI. Received for publication Sept. 22, 1994; accepted in revised form Nov. 16, 1994. 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: Joseph M. Failla, MD, Henry Ford Hospital, Department of Orthopaedic Surgery, 2799 West Grand Boulevard, Detroit, MI 48202.
456
The Journal of Hand Surgery
orrhagic pulp fat were progressively spread and excised until a cream-colored, triangular, pointed foreign body was found. This was the tip of the suspected thorn and measured 1 mm in length, just less than 1 mm in width tapering to a point, and 0.5 mm in thickness. After the object was removed, a repeat intraoperative ultrasound revealed the foreign body was no longer present, confirming that the object removed was the one detected by the ultrasound. The patient's infection resolved after 48 additional hours of intravenous antibiotic therapy and 1 week of oral antibiotic therapy; all wounds healed. Final cultures were negative for sporotrichosis.
Discussion Ultrasound has been used clinically to locate wood in soft tissues of the extremity. Splinter fragments 4 cm long were found preoperatively in the foot in one case. 1 Ultrasound was also used to locate a 6-ram long and 1-mm wide hollow glass pipette embedded within the flexor pollicis longus tendon in another case. 2 The dimensions of the foreign bodies in these two cases were, however, much larger than the 0.5mm-thick thorn found in our patient. Additionally, in the case of the glass pipette, x-ray films did not reveal it. CT scan has been mentioned as the preferred method to detect wooden foreign bodies in the soft tissues of the hand. Resolution was found to be between 1 and 2 mm. 3 The thorn tip found in this patient, which was seen in profile of .5 mm thickness, likely would not have been seen on CT scan. Thorn is a plant material similar to wood, but less dense, and the ultrasound examination revealed it clearly. This suggests that the resolution of ultrasound is as good or perhaps greater than that of CT scan in detecting small wooden or woodlike foreign
The Journal of Hand Surgery / Vol. 20A No. 3 May 1995
457
Figure 1. Longitudinal ultrasound view of the palmar radial portion of the thumb pulp. The thorn tip (arrow) is linear, hyperechoic compared to surrounding pulp, and visible anterior and parallel to the palmar cortex (*) of the distal phalanx (DP). In profile, it is seen to be 0.5 mm wide and is 1 mm long.
bodies in soft tissue. Ultrasound in this case was also crucial in locating the thorn and documenting removal o f it intraoperatively. The ability to use ultrasound in the operating room is another potential advantage over CT scan. Other advantages of ultrasound are the smaller cost compared to CT scan and lack o f radiation exposure. It may be that in some cases echogenicity of the foreign body is too similar to that o f the tissue in which it is embedded to allow detection. In such a case, an ultrasound examination would give a false negative result. However, the case reported here demonstrates that the resolution of ultrasound can be excellent. It is thus reasonable to use ultrasound examination to detect small wooden foreign bodies in the soft tis-
sue o f the hand if plain x-ray films are negative, and to reserve CT scan for cases where ultrasound examination is negative, thus increasing accuracy and reducing cost.
References 1. Kobs JK, Hansen AR, Keefe B. A retained wooden foreign body in the foot detected by ultrasonography. J Bone Joint Surg 1992;74A:296-8. 2. Levine WN, Leslie BM. The use of ultrasonography to detect a radiolucent foreign body in the hand: a case report. J Hand Surg 1993;18A:218-20. 3. Russell RC, Williamson DA, Sullivan JW, Suchy H, Suliman O. Detection of foreign bodies in the hand. J Hand Surg 1991;16A:2-11.