Electrothermal Ring Burn From a Car Battery

n Case Report
Electrothermal Ring Burn From a Car Battery
Paul A. Sibley, DO; Kenneth A. Godwin, DO
Full article available online at Healio.com/Orthopedics. Search: 20130724-31
Despite prevention efforts, burn injuries among auto mechanics are described in
the literature. Electrothermal ring burns from car batteries occur by short-circuiting
through the ring when it touches the open terminal or metal housing.
This article describes a 34-year-old male auto mechanic who was holding a wrench
when his gold ring touched the positive terminal of a 12-volt car battery and the
wrench touched both his ring and the negative terminal. He felt instant pain and had a
deep partial-thickness circumferential burn at the base of his ring finger. No other soft
tissues were injured. He was initially managed conservatively, but after minimal healing at 3 weeks, he underwent a full-thickness skin graft. The graft incorporated well
and healed by 4 weeks postoperatively. He had full range of motion.
Figure: Preoperative photograph of a circumferential, full-thickness burn to the ring finger of a
34-year-old auto mechanic, 3 weeks after injury.
The cause of ring burns has been controversial, but based on reports similar to the
current patient’s mechanism, they are most likely electrothermal burns. Gold, a metal
with high thermal conductivity, can heat up to its melting point in a matter of seconds.
Many treatments have been described, including local wound care to split- and fullthickness skin grafts. Because most burns are preventable, staff should be warned and
trained about the potential risks of contact burns. All jewelry should be removed, and
the live battery terminal should be covered while working in the vicinity of the battery.
The authors are from the Department of Orthopedic Surgery (PAS), Philadelphia College of
Osteopathic Medicine, Philadelphia; and the Department of Plastic and Reconstructive Surgery (KAG),
Aria Health, Langhorne, Pennsylvania.
The authors have no relevant financial relationships to disclose.
Correspondence should be addressed to: Paul A. Sibley, DO, Department of Orthopedic Surgery,
Philadelphia College of Osteopathic Medicine, 4190 City Ave, Philadelphia, PA 19131 ([email protected]
doi: 10.3928/01477447-20130724-31
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Electrothermal Ring Burn From a Car Battery | Sibley & Godwin
espite occupational prevention
efforts, burn injuries among auto
mechanics, although rare, are described in the literature. Electrothermal
ring burns from car batteries occur by
short-circuiting through the ring when it
touches the open terminal or metal housing. Treatment ranges from conservative
management to skin grafting, with most
burns responding well to conservative
Figure 1: Preoperative dorsal (A), palmar (B), and dorsal with long finger involvement (C) photographs
of a circumferential, full-thickness burn to the ring finger of a 34-year-old auto mechanic, 3 weeks after
injury. The asterisk denotes a superficial burn to the base of the long finger.
Case Report
A 34-year-old male auto mechanic
sustained a circumferential, deep partialthickness contact burn to his left proximal
ring finger. He was holding a stainless steel
wrench in his left hand when it touched the
negative terminal to the 12-volt car battery.
Subsequently, his gold ring touched the
positive terminal, short-circuiting through
the ring. He felt immediate sharp pain at
the base of his ring finger. He also felt
some pain at the base of his long finger. He
was able to remove the ring seconds after
the incident.
A week after his injury, he was seen
in the work health clinic. He had normal
distal sensation and brisk capillary refill.
Examination revealed mild ring finger
edema with a localized, sharp-bordered
circumferential third degree burn with
areas of anesthesia evident. No tendon or
bone involvement was observed. He had
near full range of motion that was limited
only by pain. He had a superficial contact
burn on the ulnar side of the base of his
long finger from touching the ring at the
time of the injury.
His wound was monitored conservatively with local wound care. At 3 weeks
after the injury, minimal granulation tissue was evident, and the patient was
beginning to lack a few degrees of full
metacarpophalangeal joint extension,
along with continued pain (Figure 1). No
signs of infection were observed. The decision was made to take a full-thickness
skin graft from the left medial upper arm
to cover the defect that measured 8 cm in
AUGUST 2013 | Volume 36 • Number 8
Figure 2: Intraoperative dorsal (A) and palmar (B)
photographs of a full-thickness 832-cm skin graft
being placed on the ring burn defect.
Figure 3: Dorsal (A) and palmar (B) photographs
showing the healed skin graft and full extension 4
weeks postoperatively.
circumference. After debridement of the
wound bed, an 831.5-cm defect was seen.
An 832-cm full-thickness skin graft was
harvested from the medial upper arm and
placed over the defect after appropriate
preparation (Figure 2). A tie-down bolster dressing was placed on top of the skin
graft, and an aluminum finger splint was
used to prevent shear forces. The patient
was examined in the office 14 days postoperatively. Four weeks postoperatively,
his skin graft healed, and he regained full
range of motion (Figure 3).
of the metal may occur.1,2 A gold ring conducts heat and electricity more than a platinum ring because gold has higher thermal conductivity but lower resistance.3
The authors define this type of burn as
not strictly thermal or electrical, but rather
a contact burn resulting from electrical
energy transferred to the ring. Fisher and
Dvoretzky2 reported a wrist burn from a
watch and concluded that it was electrical.
However, Attalia et al4 and Nisanci et al5
reported cases in which the ring burn was
thermal. Regan and Moss3 reported 2 similar cases, 1 of which was due to a contact
burn. Based on the mechanism described
in the latter 3 articles, which were similar
to that of the current patient, he sustained
a burn when the current passed from the
positive pole of the battery, through the
ring, then through the wrench to the negative terminal, completing the circuit. The
current did not arc or pass through the patient’s hand because no other tissues were
injured in the hand, and the proximal long
finger was superficially burned by simply
touching his heated ring.
This type of injury resembles ring
avulsion injuries described by Urbaniak et
Burn injuries from rings are rare but
have been cited in the literature. Often
seen in auto mechanics, these cases usually consist of the mechanic’s metal ring
touching the battery terminal or metal
housing while another metal object (eg, a
stainless steel wrench) also touches a metal object under the hood. Because metals
are good conductors of heat, the ring can
heat up to 1000°C (the melting point of
gold) in 1 to 2 seconds after being hooked
up to a car battery. The energy produced
can cause a local burn, and rapid melting
n Case Report
al.6 Metal ring burns cause injuries similar
to types I and IIA avulsion injuries. Type
I occurs when adequate circulation exists
and treatment is based on soft tissue management. Type IIA occurs when no bone,
nerve, or tendon involvement exists but
inadequate circulation requires vessel repair. In severe forms, even microvascular
repair may be indicated. The digital neurovascular bundles are more protected in
hand burns because the burn generally affects the volar or dorsal surface; however,
in circumferential ring burns, one must be
aware of arterial or venous insufficiency.7
Fortunately, the current patient had intact
digital circulation, and operative treatment with a skin graft sufficed. A burn is
an ongoing process, and a digit with adequate circulation may worsen with time,
proving that patient education is of utmost
Treatments documented in the literature for this injury range from conservative treatment to escharotomy to split- and
full-thickness skin grafts.3-5,8-11 The ma-
jority heal with conservative treatment;
however, patients should be aware of the
potential complications of scarring, loss
of hair follicles and sweat glands, and permanent skin hyperpigmentation.12
This type of occupational burn is not
rare, and it needs to be recognized by both
professional and amateur mechanics because many are unaware of the possibility
of this injury.8 Most jewelry-related work
injuries are due to rings or watches becoming caught in machinery, but burns should
also be included in the workplace discussion. Because most burns are preventable,
staff should be warned about the potential
risks of contact burns and trained to keep
the cover over the live battery terminal
while working in the vicinity of the battery.
Clearer warnings may be necessary to
guard individuals against wearing any metal conductors while working.
2. Fisher BK, Dvoretzky I. Bracelet burn: an unusual electric burn. Hand. 1976; 8:158-160.
3.Regan MW, Moss ALH. Circumferential
burns to the fingers associated with gold and
platinum rings. Burns. 1986; 12:360-363.
4. Attalia MF, El-Ekiabi S, Al-Baker A. A ring
burn: electric or contact? Burns. 1990; 16:6970.
5. Nisanci M, Sengezer M, Durmus M. An unusual burn injury caused by a car battery. J
Burn Care Rehabil. 2005; 26:379-381.
6. Urbaniak JR, Evans JP, Bright DS. Microvascular management of ring avulsion injuries. J
Hand Surg. 1981; 6:25.
7. Bozkurt M, Kulahci Y, Zor F. Case report: unusual ring burn injury. Burns. 2005; 31:785786.
8. Briggs PJ, Burdett-Smith P, Dickson WA.
Low-voltage battery burns. Injury. 1990;
9. Kelafant GA. Electrothermal ring burn. J Occup Med. 1995; 37:124-126.
10. Manstein CM, Manstein ME, Manstein G.
Circumferential electric burns of the ring finger. J Hand Surg. 1987; 12:808.
11. Healy CE, Purcell E, Cahill J, et al. Electrothermal ring burn. Plast Reconstr Surg. 2004;
1. Dvoretzky I, Silverman NR. Ring burn: an
unusual electric burn. J Am Acad Dermatol.
1986; 14(5):855-856.
12. Baruchin AM. Circumferential burns of the
ring finger. Ann Burns Fire Disasters. 1992;
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