Cast-saw injuries: assessing blade-to-skin contact during cast removal. Does experience or education matter?

Current Complications of Cast Removal with Oscillating Saws and a Novel Method for Reducing Such Complications: A Comparative Clinical Study

BACKGROUND

The aim of the present study was to evaluate the complications associated with conventional methods of cast removal and to compare them with the complications associated with a novel method involving the use of externally guided aids for skin protection.

METHODS

Two hundred and eight cooperative patients ≥5 years of age who had no experience with cast removal were included in the study. Patients were selected arbitrarily and were divided into 2 groups. In Group 1 (106 patients [115 casts]; 60% male; average age, 20 years), conventional protection methods were used. In Group 2 (102 patients [108 casts]; 62% male; average age, 26 years), tong-shaped, externally guided, steel plate aids were used for skin protection. After the insertion of the protective part between the skin and the cast materials, the outer portion of the aid guided the operator to stay in a safe cutting line. The cast removal procedures in each group were documented, and skin injuries, burns, patient anxiety, operator anxiety, and processing time were noted.

RESULTS

In Group 1, the skin mark/scratch rate was 18%, the full-thickness skin laceration rate was 0.9%, the burn sensation rate was 22%, and the rate of first/second-degree burns was 2.5%. Anxiety was classified as moderate by 57% of the patients and as severe by 8%. Moderate anxiety was reported by 20% of the cast operators. In Group 2, only 6% of the patients experienced moderate anxiety and the removal time was reduced by >25%. When the groups were compared with regard to severe complications such as skin laceration (resulting in bleeding), visible burn, and severe anxiety, the former 2 complications were eliminated in Group 2 but the difference between the groups was statistically significant in the last category only (p = 0.325, p = 0.247, p = 0.007, respectively).

CONCLUSIONS

Eliminating saw blade-to-skin contact with a tong-like, externally guided flexible steel aid provides a high level of safety, decreases removal time by 5 to 10 minutes (depending on cast length), and makes cast removal a better experience for both patients and operators.

LEVEL OF EVIDENCE

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Having Patience With Our Patients: A Key Technique in Cast Saw Burn Prevention

INTRODUCTION

Although regarded as conservative treatment, casting is not without risk. Injuries may be sustained during application, during cast valving, through the immobilization process, or during cast removal. We developed an experimental model to investigate safe parameters for the appropriate length of time between fiberglass cast application and bivalving for cast saw use.

METHODS

A hospital sheet was rolled into a mock "arm" on which short-arm fiberglass casts were formed. An appropriate cast saw technique was used with complete withdrawal of the saw blade from the cast material between cuts. A total of 10 casts were made for control/no vacuum (N = 5) and study/vacuum (N = 5) groups. The temperature of the saw blade was measured at 1-minute increments beginning at 3 minutes after fiberglass submersion in water. A mixed factor analysis of variance assessed differences in temperature change over time between groups with a statistical threshold of P < 0.05.

RESULTS

Casts that set for 7 minutes were associated with lower blade temperatures compared with casts that set for 3, 4, 5, and 6 minutes. The average temperature increases for the 3- to 7-minute set times without the use of vacuum were 10.08 (± 1.42), 9.38 (±1.31), 9.32 (±1.85), 8.54 (±2.10), and 5.62°F (±2.42), respectively, and with the use of vacuum, they were 9.40 (±1.14), 8.36 (±1.64), 7.84 (±2.05), 7.30 (±3.14), and 4.82°F (±2.59), respectively. Independent of vacuum use, the change in temperature was significantly different from the maximum temperature (3 minutes) beginning at 7 minutes (all P < 0.043).

DISCUSSION

A minimum of 7 minutes of set time for a fiberglass cast before attempting to bivalve using segmented cuts is associated with the smallest increase in temperature of the saw blade. Blade temperature was not affected with the vacuum enabled. Clinicians can demonstrate best practices to minimize the risk of cast saw injuries.

Novel Cast-saw Alarm System Reduces Blade-to-Skin Contact in a Pediatric Upper Extremity Model

PURPOSE

To determine the effectiveness of a novel cast-saw alarm system in minimizing the number and duration of cast-saw blade-to-skin contacts.

METHODS

Twenty orthopaedic residents removed a pair of long-arm casts applied to instrumented pediatric upper extremity models. The model and cast-saw were instrumented to detect blade to "skin" contact at a rate of 600 Hz. Each resident performed cast removal with and without the use of a cast-saw alarm, the order of which was randomized. Eleven additional "new" cast-saw users then removed pairs of casts, without and then with the cast alarm, to evaluate what effect the alarm would have on preventing blade-to-skin contact in users with no previous cast-saw experience. The number and duration of cast-saw touches were then evaluated. Statistical significance was determined paired 1-sided students t tests (number of touches).

RESULTS

For the residents (n=20), the total number of blade-to-skin contacts was 233. One hundred eighty-one blade-to-skin contacts without the alarm and 52 with the alarm (71% reduction) (t(19)=-3.42, P=0.001), averaging 6.45 more blade-to-skin contacts per cast without the alarm. The median blade-to-skin contact duration was 0.166 seconds without the alarm and 0.087 seconds with the alarm. This was a 48% reduction in contact time (P=0.073). For the inexperienced users (n=11), the total number of blade-to-skin contacts was 356, 324 blade-to-skin contacts without the alarm and 32 with the alarm (90% reduction) (t(10)=-2.78, P=0.009), averaging 26.5 more blade-to-skin contacts without the alarm. The median blade-to-skin contact duration for the novice was 0.313 seconds without the alarm and 0.1 seconds with the alarm (68% reduction). Contact time was reduced in both groups but failed to reach statistical significance. However, alarm use significantly reduced the number of touches of >0.5 seconds duration (62 vs. 3) in the novice group, P=0.0176. Blade-to-skin contact of >0.5 seconds were felt to represent touches that were more likely to result in thermal injury to a living patient.

CONCLUSION

Blade-to-skin contact can be reduced with the use of a cast-saw alarm. These effects appear most amplified in users with little prior cast-saw experience.

LEVEL OF EVIDENCE

Not applicable.

Establishing Safety Parameters for Orthopaedic Cast Saw Blade Usage

BACKGROUND

The incidence of injuries from cast saws during cast removal ranges from 0.12% to 4.3%. With 1 second or less of exposure time, a temperature of 65°C can cause partial thickness burns. Despite numerous studies that recommend avoiding the use of a dull blade, there is no objective measure of what defines dullness.

METHODS

Plaster and fiberglass casts were collected and measured after removal from patients in the clinic. A series of slabs were constructed based on these measurements. To simulate our emergency department setting, a Stryker 940 cast saw without an attached vacuum was used to split plaster slabs. A thermocouple was used to directly measure the 940-23 ion-nitride saw blade temperature after each use. To simulate our orthopaedic clinic setting, a Stryker 940 cast saw with an attached vacuum was used to split fiberglass and plaster slabs. Three blades were tested in each setting, bivalving 50 slabs each.

RESULTS

For the plaster slabs split without a vacuum, average blade temperature of the 3 blades reached 65°C on the 42nd cast. However, the individual blades exceeded 65°C on the 33rd, 31st, and 38th casts, respectively. For the fiberglass and plaster slabs split with a vacuum, average blade temperature reached a maximum of 57.5°C in the first 50 trials. Extrapolating from this data, the blade is predicted to exceed 65°C on the 104th cast.

CONCLUSIONS

When a Stryker 940 cast saw without vacuum is used to cut plaster casts, the ion-nitride blade should be changed frequently, at minimum after 60 casts have been split, or 30 casts have been bivalved. When a Stryker 940 cast saw with vacuum is used to remove fiberglass and plaster casts, the ion-nitride blade should be changed after removing 103 casts. A cast saw with an attached vacuum should be used whenever possible to minimize the risk of burning patients.

CLINICAL RELEVANCE

Determine how often a cast saw blade should be changed to minimize risk of burning patients.

Cast Saw Burn Prevention: An Evidence-Based Review

Cast saw burns are an avoidable complication of cast removal and cast splitting. These iatrogenic injuries often lead to unacceptable clinical sequalae with significant financial and legal consequences. Therefore, a considerable body of research has been directed toward cast saw burn prevention. This review of currently published data provides clinicians with a summary of the literature to guide practice based on the best available evidence, with the goal of preventing iatrogenic cast saw burns. The PubMed database was queried for articles published from 1980 until present with the following key words: cast saw burns, cast saw blades, cast saws, orthopaedic education or surgical simulation. Relevant articles were reviewed and summarized. The prevention of cast saw burns involves awareness of clinical risk factors, maintenance of equipment, use of the proper technique, and the education of novice providers. By implementing evidence-based methods, orthopaedic surgeons and associated healthcare providers can aim to eliminate these preventable complications from their practice.

Factors affecting management of children's low-risk distal radius fractures in the emergency department: a population-based retrospective cohort study

BACKGROUND

Ten randomized controlled trials over the last 2 decades support treating low-risk pediatric distal radius fractures with removable immobilization and without physician follow-up. We aimed to determine the proportion of these fractures being treated without physician follow-up and to determine whether different hospital and physician types are treating these injuries differently.

METHODS

We conducted a retrospective population-based cohort study using ICES data. We included children aged 2-14 years (2-12 yr for girls and 2-14 yr for boys) with distal radius fractures having had no reduction or operation within a 6-week period, and who received treatment in Ontario emergency departments from 2003 to 2015. Proportions of patients receiving orthopedic, primary care and no follow-up were determined. Multivariable log-binomial regression was used to quantify associations between hospital and physician type and management.

RESULTS

We analyzed 70 801 fractures. A total of 20.8% (n = 14 742) fractures were treated without physician follow-up, with the proportion of physician follow-up consistent across all years of the study. Treatment in a small hospital emergency department (risk ratio [RR] 1.86, 95% confidence interval [CI] 1.72-2.01), treatment by a pediatrician (RR 1.22, 95% CI 1.11-1.34) or treatment by a subspecialty pediatric emergency medicine-trained physician (RR 1.73, 95% CI 1.56-1.92) were most likely to result in no follow-up.

INTERPRETATION

While small hospital emergency departments, pediatricians and pediatric emergency medicine specialists were most likely to manage low-risk distal radius fractures without follow-up, the majority of these fractures in Ontario were not managed according to the latest research evidence. Canadian guidelines are required to improve care of these fractures and to reduce the substantial overutilization of physician resources we observed.

Effectiveness of a Low Fidelity Cast Removal Module in Orthopaedic Surgical Simulation

OBJECTIVE

The purpose of this study is to determine if an educational model during a surgical skills laboratory results in a significant reduction in cast saw blade temperatures generated during cast removal.

DESIGN

As part of an orthopedic resident surgical skills laboratory an Institutional Review Board-approved study was performed. A total of 17 study subjects applied a short arm cast. Everyone removed 1 short arm cast with temperatures recorded on the saw blade. Following cast removal, an educational session was conducted on proper cast removal and blade cooling techniques. Everyone then removed a second cast. Blade temperatures were recorded. To assess reproducibility, the 5 PGY-1 orthopedic residents removed a short arm cast 3 months later.

SETTING

Carolinas Medical Center, Charlotte, NC, tertiary care center PARTICIPANTS: A total of 17 study subjects with minimal casting experience (5 PGY-1 orthopedic residents and 12 senior medical students) applied a short arm cast.

RESULTS

Following the educational session there was a significant reduction in mean and mean maximum blade temperatures (p < 0.05). During the second round of cast removal assessment of blade temperatures and specific techniques to cool the blade were observed among all participants. At 3 months' time, the mean and mean maximum blade temperatures remained significantly lower than before the educational session (p < 0.05).

CONCLUSIONS

The intervention in this study reduced the maximum blade temperatures to levels below the threshold known to cause burns. This simple, low cost, and easily reproducible model can easily be disseminated across institutions and simulation laboratories.

Efficiency and Safety: The Best Time to Valve a Plaster Cast

BACKGROUND

The act of applying, univalving, and spreading a plaster cast to accommodate swelling is commonly performed; however, cast saws can cause thermal and/or abrasive injury to the patient. This study aims to identify the optimal time to valve a plaster cast so as to reduce the risk of cast-saw injury and increase spreading efficiency.

METHODS

Plaster casts were applied to life-sized pediatric models and were univalved at set-times of 5, 8, 12, or 25 minutes. Outcome measures included average and maximum force applied during univalving, blade-to-skin touches, cut time, force needed to spread, number of spread attempts, spread completeness, spread distance, saw blade temperature, and skin surface temperature.

RESULTS

Casts allowed to set for ≥12 minutes had significantly fewer blade-to-skin touches compared with casts that set for <12 minutes (p < 0.001). For average and maximum saw blade force, no significant difference was observed between individual set-times. However, in a comparison of the shorter group (<12 minutes) and the longer group (≥12 minutes), the longer group had a higher average force (p = 0.009) but a lower maximum force (p = 0.036). The average temperature of the saw blade did not vary between groups. The maximum force needed to "pop," or spread, the cast was greater for the 5-minute and 8-minute set-times. Despite requiring more force to spread the cast, 0% of attempts at 5 minutes and 54% of attempts at 8 minutes were successful in completely spreading the cast, whereas 100% of attempts at 12 and 25 minutes were successful. The spread distance was greatest for the 12-minute set-time at 5.7 mm.

CONCLUSIONS

Allowing casts to set for 12 minutes is associated with decreased blade-to-skin contact, less maximum force used with the saw blade, and a more effective spread.

CLINICAL RELEVANCE

Adherence to the 12-minute interval could allow for fewer cast-saw injuries and more effective spreading.

A Quality Improvement Initiative Reduces Cast Complications in a Pediatric Hospital

BACKGROUND

Casts, while frequently used as routine treatment in pediatric orthopaedic practice, are not without complications. At our large tertiary care pediatric hospital, the baseline rate of all casting complications was 5.6 complications per 1000 casts applied (0.56%). We tested the hypothesis that we could use quality improvement (QI) methodology to decrease the overall cast complication rate and improve patient care.

METHODS

We initiated a QI program implementing concepts derived from the Institute for Healthcare Improvement models, including Plan-Do-Study-Act cycles, to decrease our cast complication rate. A resident casting education program was developed with a competency "checklist" to ensure that casts are applied, bivalved, and removed in a safe and standardized manner to prevent patient harm. AquaCast Saw Stop Protective Strips were required to be applied with every cast application. A review of our facility's processes and procedures determined adequate measures were in place to effectively manage inventory and maintenance of cast-saw blades.

RESULTS

With the multimodal QI intervention, our cast complication rate was reduced to 1.61 complications per 1000 applications, a >90% improvement.

CONCLUSIONS

Implementation of QI concepts to perform a QI initiative resulted in a shift toward fewer cast complications, leading to overall improved patient care at a large tertiary pediatric hospital.

LEVEL OF EVIDENCE

Level II-prospective cohort study.

To Cast, to Saw, and Not to Injure: Can Safety Strips Decrease Cast Saw Injuries?

BACKGROUND

Placement and removal of fiberglass casts are among the more-common interventions performed in pediatric orthopaedic surgery offices. However, cast removal is associated with abrasive injuries and burns from the oscillating cast saw, and these injuries can occur even when the cast is removed by experienced personnel. It is unknown whether an added barrier, such as a safety strip, can mitigate injuries from blade-to-skin contact during cast removal with the oscillating saw.

QUESTIONS/PURPOSES

We asked: (1) Can a safety strip provide a physical barrier during cast removal, decreasing blade-to-skin contact? (2) Does the safety strip lessen heat transfer? (3) Will the use of the safety strip prevent cast pressure from being released when the cast is split?

METHODS

Standard long-arm fiberglass casts were removed by experienced and inexperienced healthcare personnel (n = 35) from life-sized pediatric models. A commercially available woven cast saw safety strip, commonly incorporated in waterproof cast constructs, was chosen as the protective strip. Each participant removed a cast with and without the safety strip present. All participants were blinded to the presence or absence of the safety strip at the time of cast removal. The number of touches was compared between cast removal with and without protective strips. A separate model was designed to assess prevention of heat transfer. Temperatures were recorded, using thermocouples, for three designated temperatures. Five to six trials were conducted at each designated temperature for each of two conditions, with and without the safety strip. Finally, to assess if the safety strip would prevent cast pressure from being released, a third model was used. Thirty standard short-arm casts were applied and removed from the arm models by one of the authors. Pressure data were collected from between the padding layers, in casts with and without the safety strip present, after application, univalving and bivalving each cast.

RESULTS

Use of the safety strip reduced the number of simulated skin touches compared with casts removed without the safety strip, among experienced users (mean, 9.0 [range, 1-28] versus 0.1 [range, 0-1], mean ratio, 0.0012; 95% CI, 0.002-0.063; p < 0.001) and inexperienced users (mean, 8.5 [range, 0-31] versus 0.6 [range, 0-3], mean ratio, 0.07; 95% CI, 0.03-0.15; p < 0.001). The safety strips decreased heat transfer, preventing temperatures at the cast-skin interface from reaching 50 °C. Finally, after splitting the cast, with the numbers available, there was no increase in the pressure beneath the casts in those with the safety strip present (mean without, 0.23 [SD, 0.070] versus safety strip in the padding 0.20 [SD, 0.091] and safety strip on top padding, 0.21 [SD, 0.090]; p = 0.446 and p = 0.65 respectively).

CONCLUSIONS

Our study showed the effectiveness of a safety strip in reducing simulated touches with the oscillating cast saw during cast splitting. Additional studies are warranted to investigate the clinical use and utility of the safety strip in practice.

CLINICAL RELEVANCE

The findings of this study suggest that using safety strips in clinical practice could decrease blade-to-skin contact and therefore minimize cast saw injuries. However, validation of these findings in the clinical setting is necessary before drawing a definitive conclusion.

How to Avoid Cast Saw Complications

BACKGROUND

As casts are routinely used in pediatric orthopaedics, casts saws are commonly used to remove such casts. Despite being a viewed as the "conservative" and therefore often assumed safest treatment modality, complications associated with the use of casts and cast saws occur.

METHODS

In this manuscript, we review the risk factors associated with cast saw injuries.

RESULTS

Cast saw injuries are thermal or abrasive (or both) in nature. Thermal risk factors include: cast saw specifications (including a lack of attached vacuum), use of a dull blade, cutting in a concavity, too thin padding, and overly thick casting materials. Risk factors associated with abrasive injuries include: sharp blades, thin padding, and cutting over boney prominences. Because nearly all clinicians contact the skin with the blade during cast removal, appropriate "in-out technique" is critical. Such technique prevents a hot blade from remaining in contact with the skin for any significant time, diminishing the risk of burn. Similarly, using such technique prevents "dragging the blade" that may pull the skin taught, cutting it. It may be useful to teach proper technique as perforating a cast rather than cutting a cast.