a b s t r a c t

Introduction: Emergency physicians may have difficulty removing modern rings made of hard metals such as titanium and tungsten carbide. These metals are exceptionally difficult or impossible to remove using standard ring cutters. Numerous Alternative techniques for removal have been described, including the “umbilical tape” or “string technique” and, in the case of tungsten carbide, breaking the ring using locking pliers.

Objective: We sought to compare the speed and effectiveness of tungsten carbide Ring removal using these two techniques.

Methods: Ten tungsten carbide rings were placed upon the finger of a standard medical simulation mannequin. The rings chosen were one-half size smaller than the mannequin’s finger. Edema distal to the ring was simulated using foam tape. A single novice operator performed 10 trials using each of the techniques after a 10-minute orientation session. The success or failure of the technique and the time for removal were recorded for each trial. The mean removal times for the trials were compared using a paired t test.

Results: All trials were successful. The rings were removed substantially faster using the locking pliers method (mean 23.1 seconds [95% CI 15.4-30.8] vs. mean 135.4 seconds [95% CI 130.2-150.6]). However, the locking pliers technique destroyed all rings and caused sharp ring fragments to be thrown up to 37 in.

Conclusions: Both the umbilical tape or string technique and the locking pliers technique successfully removed tungsten carbide rings in our model. The locking pliers technique is significantly faster but destroys the ring and creates potentially harmful shrapnel.

(C) 2013

Introduction

Emergency physicians commonly face the challenge of removing a metal ring from an injured digit. Occasionally, a ring must be removed after it has become entrapped on a digit when, for example, a person places a ring which is too small on their finger and edema prevents the ring from being removed. Additionally, other conditions may necessitate the urgent removal of a ring including: infection, burns, changes in volume status resulting in digital edema, and Allergic reactions. All of these conditions, if the ring is not removed in a timely manner, can compromise circulation to the distal digit with resultant Ischemic injury.

While a variety of techniques for ring removal have been described, one most often employed by medical personnel is cutting the ring using specially designed cutting tools. The most commonly used ring cutters are made of steel and are either manually operated or battery powered. These devices work well on rings made of gold or silver. Metal hardness is measured on the 10-point Mohs hardness scale with lower numbers being assigned to softer metals. Gold and Silver have a Mohs scale hardness rating of 2.5 to 3.0 [1,2]. Steel has a

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E-mail address: [email protected] (E.F. Reichman).

hardness rating of 4.0 to 4.5 and hardened steel has a rating of 7.0 to

8.0 [1,2]. However, in recent years patients have presented to emergency departments with rings made of much harder materials like titanium (Mohs hardness scale rating of 6.0) and tungsten- carbide (Mohs hardness scale rating of 8.5-9.0. There are anecdotal reports of titanium rings being cut using hardened steel or diamond (Mohs hardness rating 10.0) edged cutters. While tungsten-carbide appears to be nearly impervious to ring cutters, some have reported breaking these rings by applied pressure using a locking pliers [3]. The carbon lattice structure of the carbide ring behaves more like glass in that it will shatter under compressive pressure rather than bend like other metal rings. This is an important property of the ring, allowing one to apply compressive forces without risking deforming the ring and further constricting the digit.

Because tungsten carbide rings cannot be cut, the “umbilical tape technique” or “string technique” could potentially be an effective alternative way to remove them. This method of ring removal is performed by passing a strip of cloth tape (eg, umbilical tape) or string (eg, suture material) underneath the ring from distal to proximal and then tightly wrapping the tape around the digit, distal to the entrapped ring. The purpose of this wrapping is to compress the edema in the finger, effectively rendering it less edematous. The proximal piece of tape is then used to unwrap the tape. Each time the tape is unwound it pushes the ring distally. If all goes as planned,

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the ring is eventually pushed beyond the proximal interphalangeal (PIP) joint onto the thinner, distal finger from which it can be easily removed (Fig. 1). While this method of ring removal is not always effective, it offers the advantage of preserving the ring and, for tungsten carbide rings, it might be one of the only ways to successfully remove an entrapped ring. However, the medical literature is very limited regarding these methods of ring removal and the authors are not aware of any studies have been conducted comparing these methods to one another.

In this study we sought to compare the speed and effectiveness of fracturing tungsten carbide rings using locking pliers with the umbilical tape technique. The primary objective was the comparative effectiveness of the two techniques in successful ring removal. The secondary objective was mean difference in time to ring removal.

Methods

A medical simulation mannequin served as the model for this experiment. A standard jeweler’s ring-sizing tool was used to determine the mannequin’s finger size. Ten commercially available tungsten carbide rings one-half size smaller than the measured size of the mannequin finger were purchased. The rings were size 7 and circular. The ring dimensions were 4.7 mm wide with a thickness of

mm. Once the ring was placed upon the mannequin’s finger, edema was simulated by wrapping the portion of the finger distal to the ring with foam tape. Ten trials were performed by a third-year emergency medicine resident without any clinical experience with either of these ring Removal techniques. Prior to testing, the resident received a 10-minute didactic presentation and demonstration of the two techniques by one of the authors (EFR). During each trial, the resident first performed the umbilical tape technique followed by the locking pliers technique. Removal speed was measured in seconds with the start time triggered by the resident picking up either the tape or pliers and the stop time when the ring was removed from the finger or fractured into pieces. Effectiveness was dichotomous and defined by the success or failure of ring removal. If either technique took longer than 5 minutes the attempt would be classified as a failure. A single novice provider was used to control for both inter-provider variation and experience.

The umbilical tape technique was performed using a piece of umbilical tape 24 in. long and 0.25 in. wide. The tape was inserted

under the ring, from distal to proximal, with the aid of a hemostat (Fig. 1A). Approximately 6 to 7 cm of the tape was pulled proximal to the ring (Fig. 1B). The tape distal to the ring was wound tightly around the digit in a closed spiral (Fig. 1C). The turns of the umbilical tape overlapped one another by approximately 50% so that no “skin” was interposed between the turns of the tape. The tape was wound distally to a point just beyond the PIP joint (Fig. 1C). The novice operator performing the procedure grasped the proximal end of the tape and unwounded it distally while maintaining distal traction (Fig. 1D). The tape was continuously unwound until the ring passed the PIP joint (Fig. 1E) and could be easily removed (Fig. 1F).

The attempts to fracture the ring were conducted using a standard, medium-sized locking pliers (eg, Vice-Grips) obtained from a local hardware store. The jaws of the locking pliers were adjusted so that, when closed, they would grip the ring snuggly without being overly tight. They were then opened and the tightening screw was turned one-quarter of a turn to the right to slightly increase the grip pressure on the ring. The pliers were then reapplied to the ring (Fig. 2). This process was repeated until the ring was heard, seen, or felt to fracture. After each successful removal attempt, the mannequin’s finger was inspected for evidence that removal of the ring might have caused injury to the finger.

The times from the beginning of the procedure until the ring was removed from the finger were measured and a mean time for removal using each method was calculated. These means were compared using a paired t test and 95% confidence intervals were calculated for each sample mean.

Results

There was no difference in the primary objective as both techniques were 100% effective in ring removal with no attempt taking more than 5 minutes. The locking pliers technique removed the ring significantly faster than the umbilical tape technique (P b .001) (Table 1). The mean time to removal for the tape technique was 135.4 seconds (95% CI 130.2-150.6) compared to 23.1 seconds (95% CI 15.4- 30.8) for the locking pliers technique. The fastest umbilical tape ring removal time (95 seconds) was almost twice the slowest plier removal time (48 seconds). The slowest umbilical tape removal time (164 seconds) was nearly 15 times longer than the fastest plier removal time (11 seconds). However, the locking pliers technique

Fig. 1. The umbilical tape technique.

Adapted with permission from Reichman EF (ed.): Emergency Medicine Procedures, 2nd ed. McGraw-Hill, New York, 2013.

1518 C.L. Gardiner et al. / American Journal of Emergency Medicine 31 (2013) 1516-1519

balance clinical necessity of rapid removal with the cost of ring destruction and patient preference. The single operator in our study did not appear to improve his speed of removal consistently over the trials with the umbilical tape technique suggesting that the Skill acquisition for that technique may take more than 10 attempts. The operator did improve their speed with the locking pliers technique over the 10 trials suggesting more rapid skill acquisition.

5. Limitations

Fig. 2. A locking pliers is used to remove a ring.

Adapted with permission from Reichman EF (ed.): Emergency Medicine Procedures, 2nd ed. McGraw-Hill, New York, 2013.

destroyed all ten tungsten carbide rings and caused some ring fragments to be propelled up to 37 in. away from the mannequin. The mannequin finger did not sustain any superficial damage (e.g. cuts, abrasions, deformities).

Discussion

Several techniques for the emergency removal of rings have been described. Many commercially available cutting tools are very effective in the removal of soft metal (e.g. gold, silver) rings but fail when applied to harder metals like titanium and tungsten carbide. It was previously suggested that surgical degloving or amputation of the digit might be the only way to remove these rings [4]. However, recent case reports and studies have shown that locking pliers, diamond-tipped dental drills, and cloth or nylon tape can successfully remove these rings [4-6]. Several authors have extensively described the umbilical tape or string technique and its modifications [5,7,8]. As described, this technique uses a string or a piece of narrow tape to compress edematous tissue, exsanguinate the digit, and then facilitate passage of the ring over the PIP joint, which is often the major impediment to ring removal. However, this technique is not recommended if the patient has an associated finger laceration, finger fracture, or an embedded ring [8,9]. Use of other materials such as cotton gauze, rubber tourniquets, and Penrose drains has also been described [5,10,11]. Each of these materials has certain practical advantages. Since they are wider than string or suture material, shorter lengths and fewer turns are required to encircle the finger. It is also easier to wind these materials around the digit without interposition of the skin between the turns (Fig. 1).

Many rings cannot be removed with the previously described techniques. These rings are also resistant to cutting using a carbide, diamond, or steel cutting disk on a ring cutter, placing the patient at risk for ischemic injury to the digit. As our study demonstrates, rings made of tungsten carbide can be quickly and effectively removed by fracturing them in a controlled fashion using locking pliers. It is also true that all of the rings in our study were removed using the umbilical tape technique. However, the locking pliers removed the

The major limitation of this study is that these techniques were applied to a mannequin finger. It is, therefore, impossible to assess patient discomfort or to estimate the potential for injury as a result of the removal techniques. We simulated edema by wrapping the mannequin finger in foam tape. This technique has not been demonstrated to effectively replicate the edema resulting from an entrapped ring. Passing the umbilical tape under the ring, compres- sion of finger edema, and ring removal may all be more difficult in an actual edematous finger. The mannequin finger is also not an adequate surrogate for a human finger in terms of assessing injury.

Only one operator performed all trials. This allowed for consis- tency in the removal techniques and eliminated the confounder that might be introduced by the presence of multiple operators. The use of a single operator introduces the concern that the operator may improve their technique and experience greater success with successive attempts. However, as our data demonstrates, the operator’s performance with the umbilical technique was variable throughout the trials. The operator was also a novice and therefore experienced providers with advanced skills in the umbilical tape removal technique may have shorter removal times. On the other hand, the operator was able to employ the locking plier technique more quickly in the latter trials. It is possible that other providers might have performed better or more poorly.

This study was also limited to ten trials of each technique using the same size ring. It is unclear whether more trials would result in more time or less time variation. Finally, using rings of differing thickness may have altered the results. Thinner rings may have been fractured more easily and quicker with the locking pliers than thicker rings, although the actual clinical impact of ring thickness on removal may not be significant. Ring thickness would probably not affect the results of the umbilical tape technique.

6. Conclusion

Tungsten carbide is known for its hardness, durability, and limited susceptibility to scratches. These features have made it a popular choice for jewelry and especially for wedding rings. Removal of these rings can prove very challenging, as most commercially available ring cutters cannot cut through tungsten carbide. We have evaluated two

Table 1

The time required to remove a tungsten carbide ring: the umbilical tape technique vs. the locking pliers technique.

rings substantially faster, albeit at the cost of complete destruction of the ring and with the attendant risk of fragmentation producing small	Attempt number Time for removal using the umbilical tape technique (s)		Time for removal using the locking pliers technique (s)
projectile shards. In fact, we recommend that this technique only be used in closed areas when the patient and all attendants can be	1 2	156 157	15 48
assured adequate protection of their eyes and skin. Small projectile	3	126	41
fragments from the ring occurred in half (5 of 10) of the rings	4	160	26

removed using the locking pliers. Generally, the umbilical tape technique time averaged well over 2 minutes while the locking pliers technique time averaged well under 30 seconds. The clinical

5	123	16
6	164	21
7	106	25
8	147	16
9	95	11
10	120	12
Mean time (95% CI)	135.4 (120.2-150.6)	23.1 (15.4-30.8)

importance of this time difference will likely depend on the urgency for removal based upon the rate of ongoing swelling, evidence of digit ischemia and level of patient discomfort. The provider will have to

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techniques for the removal of tungsten carbide rings. The umbilical tape technique takes longer but preserves the ring whereas the locking pliers removes the ring more quickly but cause irreparable damage to the ring and can produce ring shards which can be projected a considerable distance. Both techniques use readily available materials and are easily mastered by novice operators.

Acknowledgments

This work was supported by funds derived from the Clive, Nancy, and Pierce Runnells Professorship in Emergency Medicine.

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