ORIGINAL ARTICLE
Effect of Casting Material on the Cast Pressure After Sequential Cast Splitting Aaron Roberts, DO, CPT, MC, K. Aaron Shaw, DO, CPT, MC, Shawn E. Boomsma, DO, CPT, MC, and Craig D. Cameron, DO
Background: Circumferential casting is a vital component of nonoperative fracture management. These casts are commonly valved to release pressure and decrease the risk of complications from swelling. However, little information exists regarding the effect of different casting supplies on the pressure within the cast. Methods: Seventy-five long-arm casts were performed on human volunteers, divided between 5 experimental groups with 15 casts in each groups. Testing groups consisted of 2 groups with a plaster short-arm cast overwrapped with fiberglass to a long arm with either cotton or synthetic cast padding. The 3 remaining groups included fiberglass long-arm casts with cotton, synthetic, or waterproof cast padding. A pediatric blood pressure cuff bladder was placed within the cast and inflated to 100 mm Hg. After inflation, the cast was sequentially released with pressure reading preformed after each stage. Order of release consisted of cast bivalve, cast padding release, and cotton stockinet release. After release, the cast was overwrapped with a loose elastic bandage. Difference in pressure readings were compared based upon the cast material. Results: Pressures within the cast were found to decrease with sequential release of cast. The cast type had no effect of change in pressure. Post hoc testing demonstrated that the type of cast padding significantly affected the cast pressures with waterproof padding demonstrating the highest pressure readings at all timepoints in the study, followed by synthetic padding. Cotton padding had the lowest pressure readings at all time-points. Discussion: Type of cast padding significantly influences the amount of pressure within a long-arm cast, even after bivalving the cast and cutting the cast padding. Cotton cast padding allows for the greatest change in pressure. Clinical Relevance: Cotton padding demonstrates the greatest change in pressure within a long-arm cast after undergoing bivalve. Synthetic and waterproof cast padding should not be used in the setting of an acute fracture to accommodate swelling. From the Department of Orthopaedic Surgery, Dwight D. Eisenhower Army Medical Center, Fort Gordon, GA. The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of Defense or US Government. The authors are employees of the US government. The authors of this study have no financial disclosures relevant to the study topic. The authors declare no conflicts of interest. Reprints: Kenneth A. Shaw, DO, CPT, MC, Department of Orthopaedic Surgery, 300 East Hospital Road, Fort Gordon, GA 30905. E-mail: [email protected]. Copyright r 2015 Wolters Kluwer Health, Inc. All rights reserved.
J Pediatr Orthop
Volume 00, Number 00, ’’ 2015
Key Words: long-arm casting, bivalve, cast padding, cast pressure (J Pediatr Orthop 2015;00:000–000)
N
onoperative management of fractures by splinting and casting is an integral part of fracture management. This is especially true regarding pediatric fractures. The cast must be able to securely hold a fracture in appropriate alignment, while simultaneously allowing for continued distal perfusion of the casted extremity. Circumferential casting in an acute setting can result in increased pressures within the cast as the soft tissue swells as a result of the initial injury.1,2 As the swelling persists, this can develop into compartment syndrome, a potentially devastating complication characterized by prolonged periods of elevated intracompartmental pressure causing irreversible damage to muscle and nerves.3 In prior research it has been shown that by valving the cast, the pressure within the cast can be significantly reduced.4,5 In addition, studies have shown that cutting the cast padding in combination with cast valving also reduces the cast pressures.4,5 This study was designed to evaluate the effect of various casting material on the pressure within a cast, followed by sequential release of the cast. This information may help guide clinicians on the impact of different materials on the cast pressures, and potentially help reduce complications from soft tissue swelling.
METHODS Upon receiving approval from the Institutional Review Board, experimental testing began, applying 75 total casts, performed on human volunteers. Pressure readings were provided with the use of a bladder from a pediatric blood pressure cuff (Welch Allyn Inc., Skaneateles Falls, NY). The bladder was placed onto the volar aspect of the volunteer’s forearm, held in place with a 2-inch diameter cotton stockinet (3M, St. Paul, MN). The cast padding was applied, 3 inches wide, 2 layers thick, as a long-arm cast and the casting material was applied (Fig. 1). Once the cast was applied and allowed to set, the blood pressure bladder was inflated to 100 mm Hg. After inflation, the cast underwent sequential release of each layer of the cast with recordings of pressure reading after www.pedorthopaedics.com |
1
Copyright r 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Roberts et al
J Pediatr Orthop
Volume 00, Number 00, ’’ 2015
Statistical analyses were performed using SPSS statistical software version 21 (IBM, Armonk, NY). Experimental groups were analyzed using mixed-design analysis of variance. Post hoc comparisons between casting material and cast padding were performed using a Scheffe’s test to control for type II errors. Statistical significance was predetermined as P < 0.05.
RESULTS
FIGURE 1. Illustration of study design demonstrating layers of cast. 1 = stockinet, 2 = cast padding, 3 = casting material.
each stage of cast release. The cast was first bivalved along the radial and ulnar aspect of the forearm, 180 degrees away from each other, utilizing an oscillating cast saw (Stryker CastVac, Stryker Instruments, Kalamazoo, MI). The cast padding was cut at the previously bivalved areas, followed by the stockinet. After the stockinet was cut and pressure reading recorded, a 3-inch elastic wrap (Econowrap, Vitality Medical, Salt Lake City, UT) was wrapped loosely around the cast and a pressure reading recorded. We used 2 separate independent variables for analysis: casting material and type of cast padding. Two separate types of casts were applied. The first consisted of a plaster short-arm cast consisting of 5 layers of 4-inch wide plaster slabs applied to the volar and dorsal forearm and overwrapped with 3-inch wide plaster rolls (Gypsona, BSN Medical, Charlotte, NC) which was then overwrapped after allowing it to dry for 10 minutes as a long-arm cast, 2 layers thick, with 3-inch wide fiberglass casting material (Scotchcast Plus Casting Tape, 3M). The second cast consisted of a long-arm cast, applied 2 layers thick with 3-inch wide fiberglass casting material (Scotchcast Plus Casting Tape, 3M). Cast padding consisted of either (A) cotton padding (Webril-Kendall, Mansfield, MA), (B) synthetic padding (Dacron polyester material, 3M), or (C) waterproof padding (3M Scotchcast Wet Padding, 3M). A total of 5 experimental groups were used for this study. An a priori power analysis showed that a minimum sample size of 15 subjects per condition should provide sufficient power of 0.80 and alpha set at 0.05, for a total of 75 casts. Groups consisted of a combination of casting material and cast padding as depicted below. (1) Fiberglass cast with cotton padding. (2) Fiberglass cast with synthetic cast padding. (3) Fiberglass cast with waterproof cast padding. (4) Plaster and fiberglass cast with cotton padding. (5) Plaster and fiberglass cast with synthetic cast padding.
2 | www.pedorthopaedics.com
Recorded pressures of the 5 casting groups are depicted in Figure 2, following sequential release. Results from the mixed-design analysis of variance found statistically significant differences between all time-points of the sequential release of the casts (Table 1). The type of casting material, fiberglass compared with plaster and fiberglass, was found to have no effect on the cast pressures (P > 0.05) (Table 2). Post hoc analysis of the effect of cast padding found significant effects on the cast pressure (Figs. 2, 3). Waterproof cast padding demonstrated significantly higher pressure readings (P < 0.05) at all time-points during sequential cast release except after stockinet release and elastic bandage application when synthetic cast padding demonstrated similarly elevated pressure readings. Cotton padding had the lowest pressure readings following cast bivalve, cutting of cast padding, and application of elastic bandage (P < 0.05).
DISCUSSION Although cast immobilization remains the recommended treatment intervention for many adult and pediatric orthopaedic conditions, it is not without potential complications. These complications include the risk of joint stiffness from prolonged immobilization, pressure sores and skin breakdown, thermal injury from cast placement, cast saw burns sustained during removal, and compartment syndrome.2,6,7 The most serious of cast-related complications is compartment syndrome. Volkmann8 first recognized the potential of tight bandaging to cause prolonged blockage in arterial flow, resulting in ischemia and the contracture that now bears his name. Bingold4 was the first to measure pressures after casting in a simulated forearm model,
FIGURE 2. Change in pressure at set time-points as a function of cast and padding type. Copyright
r
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright r 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
J Pediatr Orthop
Volume 00, Number 00, ’’ 2015
Effect of Casting Material on the Cast Pressure
TABLE 1. Results of Mixed-design Analysis of Variance Assessing Pressure Values as a Function of Different Study Time-points Condition Initial to bivalve Initial to cut pad Bivalve to cut pad Cut padding pressure Loose ace wrap pressure
F
P
45.55 3.80 42.69 3.80 4.28
< 0.001 0.007 < 0.001 0.007 0.004
finding an 80% decrease in pressure after bivalving. Garfin assessed the ability of cast valving to decrease intracompartmental pressures under plaster casts applied to dogs, finding a 65% reduction in pressure upon univalving a cast. An additional 10% decrease was found with cutting of the underlying cast padding.9 Additional studies have since investigated the impact of different materials on casting pressure, finding increased pressures with the use of fiberglass casting,10,11 as well as casting technique.10 No study to date has investigated the effect of different types of cast padding. We found significant higher cast pressures when using synthetic and waterproof cast padding, in comparison with cotton padding. These findings were unaffected by the type of cast applied. Similar to previous studies,1,4,9 we found a significant pressure drop after cast bivalve. A 75% pressure decrease occurred with the cotton padding group following cast bivalve, with an additional 10% decrease after the padding was released. The decrease in pressure after releasing the cast padding was more significant for the synthetic (20%) and waterproof padding groups (25%). The application of a loose elastic bandage after complete release of the cast elevated the cast pressure to a point that was significantly higher than the cast pressures after cutting the cast padding. The degree of pressure elevation varied based upon padding type with synthetic and waterproof cast padding groups demonstrating higher pressures than the cotton padding groups. It is important to recognize that the implementation of valving to a circumferential cast has not been prospectively shown to decrease the incidence of cast-related compartment syndrome. Schulte et al12 performed a randomized controlled trial of 100 pediatric patient requiring closed reduction for a forearm fracture. Patients were randomized into either a closed or valved circumferential semirigid cast. The authors found no significant difference in cast-related complications with only 1 patient
TABLE 2. Results of Planned Comparison of Cast Type at Various Study Time-points Conditions Initial to bivalve Initial to cut pad Bivalve to cut pad Lose ace to tight ace Cut padding pressure Loose ace wrap pressure
Copyright
r
FIGURE 3. Percentage of change in the cast pressure from initial pressure following cast bivalve and padding cut.
in the closed casting group requiring secondary splitting for lymphedema. In addition, the process of valving negatively affects the biomechanical strength of the cast construct.13 Limitations of this study largely reflect the experimental methods. Although we used human volunteers to include the viscoelastic nature of the soft tissues of the forearm that are difficult to reproduce with nonliving models, the model does not account for the soft tissue injury that accompanies acute fractures of the forearm. As such, our results may not extrapolate to the acutely injured forearm, however, our results fall within previously reported values. In addition, we did not incorporate the 3point molding technique commonly utilized with reduction and casting of acute forearm fractures, which has been shown to affect the cast pressure.7
CONCLUSIONS Although compartment syndrome is a rare complication following cast immobilization, it should be considered in all patients, particularly those who may be unable to alert the provider of the classic symptoms, such as the young or incapacitated. We demonstrate that 1 factor that should be contemplated is the casting material, with cotton casting padding demonstrating significant decreased pressure readings as compared with synthetic and waterproof cast padding. Bivalving a circumferential cast resulting in significant reduction in the cast pressure reading, and the additional release of the underlying cast padding allows for further decrease in pressure. The application of an elastic bandage to a released cast results in a small, but significant increase in the cast pressure compared with released cast padding. For the acutely fractured forearm fracture, consideration should be given for using cotton cast padding to better accommodate soft tissue swelling.
P
REFERENCES
0.52 0.23 0.21 0.31 0.23 0.73
1. Walker RW, Draper E, Cable J. Evaluation of pressure beneath a split above elbow plaster cast. Ann R Coll Surg Engl. 2000;82: 307–310. 2. Halanski M, Noonan KJ. Cast and splint immobilization: complications. J Am Acad Orthop Surg. 2008;16:30–40. 3. Mashru RP, Herman MJ, Pizzutillo PD. Tibial shaft fractures in children and adolescents. J Am Acad Orthop Surg. 2005;13:345–352.
2015 Wolters Kluwer Health, Inc. All rights reserved.
www.pedorthopaedics.com |
3
Copyright r 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Roberts et al
4. Bingold AC. On splitting plasters. A useful analogy. J Bone Joint Surg Br. 1979;61-b:294–295. 5. Younger AS, Curran P, McQueen MM. Backslabs and plaster casts: which will best accommodate increasing intracompartmental pressures? Injury. 1990;21:179–181. 6. Hutchinson MJ, Hutchinson MR. Factors contributing to the temperature beneath plaster or fiberglass cast material. J Orthop Surg Res. 2008;3:10. 7. Deignan BJ, Iaquinto JM, Eskildsen SM, et al. Effect of pressure applied during casting on temperatures beneath casts. J Pediatr Orthop. 2011;31:791–797. 8. von Volkmann R. Ischaemic muscle paralyses and contractures. 1881. Clin Orthop Relat Res. 2007;456:20–21.
4 | www.pedorthopaedics.com
J Pediatr Orthop
Volume 00, Number 00, ’’ 2015
9. Garfin SR, Mubarak SJ, Evans KL, et al. Quantification of intracompartmental pressure and volume under plaster casts. J Bone Joint Surg Am. 1981;63:449–453. 10. Davids JR, Frick SL, Skewes E, et al. Skin surface pressure beneath an above-the-knee cast: plaster casts compared with fiberglass casts. J Bone Joint Surg Am. 1997;79:565–569. 11. Marson BM, Keenan MA. Skin surface pressures under short leg casts. J Orthop Trauma. 1993;7:275–278. 12. Schulte D, Habernig S, Zuzak T, et al. Forearm fractures in children: split opinions about splitting the cast. Eur J Pediatr Surg. 2014;24:163–167. 13. Nielsen DM, Ricketts DM. Where to split plaster casts. Injury. 2005;36:588–589.
Copyright
r
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright r 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Effect of Casting Material on the Cast Pressure After Sequential Cast Splitting Aaron Roberts, DO, CPT, MC, K. Aaron Shaw, DO, CPT, MC, Shawn E. Boomsma, DO, CPT, MC, and Craig D. Cameron, DO
Background: Circumferential casting is a vital component of nonoperative fracture management. These casts are commonly valved to release pressure and decrease the risk of complications from swelling. However, little information exists regarding the effect of different casting supplies on the pressure within the cast. Methods: Seventy-five long-arm casts were performed on human volunteers, divided between 5 experimental groups with 15 casts in each groups. Testing groups consisted of 2 groups with a plaster short-arm cast overwrapped with fiberglass to a long arm with either cotton or synthetic cast padding. The 3 remaining groups included fiberglass long-arm casts with cotton, synthetic, or waterproof cast padding. A pediatric blood pressure cuff bladder was placed within the cast and inflated to 100 mm Hg. After inflation, the cast was sequentially released with pressure reading preformed after each stage. Order of release consisted of cast bivalve, cast padding release, and cotton stockinet release. After release, the cast was overwrapped with a loose elastic bandage. Difference in pressure readings were compared based upon the cast material. Results: Pressures within the cast were found to decrease with sequential release of cast. The cast type had no effect of change in pressure. Post hoc testing demonstrated that the type of cast padding significantly affected the cast pressures with waterproof padding demonstrating the highest pressure readings at all timepoints in the study, followed by synthetic padding. Cotton padding had the lowest pressure readings at all time-points. Discussion: Type of cast padding significantly influences the amount of pressure within a long-arm cast, even after bivalving the cast and cutting the cast padding. Cotton cast padding allows for the greatest change in pressure. Clinical Relevance: Cotton padding demonstrates the greatest change in pressure within a long-arm cast after undergoing bivalve. Synthetic and waterproof cast padding should not be used in the setting of an acute fracture to accommodate swelling. From the Department of Orthopaedic Surgery, Dwight D. Eisenhower Army Medical Center, Fort Gordon, GA. The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of Defense or US Government. The authors are employees of the US government. The authors of this study have no financial disclosures relevant to the study topic. The authors declare no conflicts of interest. Reprints: Kenneth A. Shaw, DO, CPT, MC, Department of Orthopaedic Surgery, 300 East Hospital Road, Fort Gordon, GA 30905. E-mail: [email protected]. Copyright r 2015 Wolters Kluwer Health, Inc. All rights reserved.
J Pediatr Orthop
Volume 00, Number 00, ’’ 2015
Key Words: long-arm casting, bivalve, cast padding, cast pressure (J Pediatr Orthop 2015;00:000–000)
N
onoperative management of fractures by splinting and casting is an integral part of fracture management. This is especially true regarding pediatric fractures. The cast must be able to securely hold a fracture in appropriate alignment, while simultaneously allowing for continued distal perfusion of the casted extremity. Circumferential casting in an acute setting can result in increased pressures within the cast as the soft tissue swells as a result of the initial injury.1,2 As the swelling persists, this can develop into compartment syndrome, a potentially devastating complication characterized by prolonged periods of elevated intracompartmental pressure causing irreversible damage to muscle and nerves.3 In prior research it has been shown that by valving the cast, the pressure within the cast can be significantly reduced.4,5 In addition, studies have shown that cutting the cast padding in combination with cast valving also reduces the cast pressures.4,5 This study was designed to evaluate the effect of various casting material on the pressure within a cast, followed by sequential release of the cast. This information may help guide clinicians on the impact of different materials on the cast pressures, and potentially help reduce complications from soft tissue swelling.
METHODS Upon receiving approval from the Institutional Review Board, experimental testing began, applying 75 total casts, performed on human volunteers. Pressure readings were provided with the use of a bladder from a pediatric blood pressure cuff (Welch Allyn Inc., Skaneateles Falls, NY). The bladder was placed onto the volar aspect of the volunteer’s forearm, held in place with a 2-inch diameter cotton stockinet (3M, St. Paul, MN). The cast padding was applied, 3 inches wide, 2 layers thick, as a long-arm cast and the casting material was applied (Fig. 1). Once the cast was applied and allowed to set, the blood pressure bladder was inflated to 100 mm Hg. After inflation, the cast underwent sequential release of each layer of the cast with recordings of pressure reading after www.pedorthopaedics.com |
1
Copyright r 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Roberts et al
J Pediatr Orthop
Volume 00, Number 00, ’’ 2015
Statistical analyses were performed using SPSS statistical software version 21 (IBM, Armonk, NY). Experimental groups were analyzed using mixed-design analysis of variance. Post hoc comparisons between casting material and cast padding were performed using a Scheffe’s test to control for type II errors. Statistical significance was predetermined as P < 0.05.
RESULTS
FIGURE 1. Illustration of study design demonstrating layers of cast. 1 = stockinet, 2 = cast padding, 3 = casting material.
each stage of cast release. The cast was first bivalved along the radial and ulnar aspect of the forearm, 180 degrees away from each other, utilizing an oscillating cast saw (Stryker CastVac, Stryker Instruments, Kalamazoo, MI). The cast padding was cut at the previously bivalved areas, followed by the stockinet. After the stockinet was cut and pressure reading recorded, a 3-inch elastic wrap (Econowrap, Vitality Medical, Salt Lake City, UT) was wrapped loosely around the cast and a pressure reading recorded. We used 2 separate independent variables for analysis: casting material and type of cast padding. Two separate types of casts were applied. The first consisted of a plaster short-arm cast consisting of 5 layers of 4-inch wide plaster slabs applied to the volar and dorsal forearm and overwrapped with 3-inch wide plaster rolls (Gypsona, BSN Medical, Charlotte, NC) which was then overwrapped after allowing it to dry for 10 minutes as a long-arm cast, 2 layers thick, with 3-inch wide fiberglass casting material (Scotchcast Plus Casting Tape, 3M). The second cast consisted of a long-arm cast, applied 2 layers thick with 3-inch wide fiberglass casting material (Scotchcast Plus Casting Tape, 3M). Cast padding consisted of either (A) cotton padding (Webril-Kendall, Mansfield, MA), (B) synthetic padding (Dacron polyester material, 3M), or (C) waterproof padding (3M Scotchcast Wet Padding, 3M). A total of 5 experimental groups were used for this study. An a priori power analysis showed that a minimum sample size of 15 subjects per condition should provide sufficient power of 0.80 and alpha set at 0.05, for a total of 75 casts. Groups consisted of a combination of casting material and cast padding as depicted below. (1) Fiberglass cast with cotton padding. (2) Fiberglass cast with synthetic cast padding. (3) Fiberglass cast with waterproof cast padding. (4) Plaster and fiberglass cast with cotton padding. (5) Plaster and fiberglass cast with synthetic cast padding.
2 | www.pedorthopaedics.com
Recorded pressures of the 5 casting groups are depicted in Figure 2, following sequential release. Results from the mixed-design analysis of variance found statistically significant differences between all time-points of the sequential release of the casts (Table 1). The type of casting material, fiberglass compared with plaster and fiberglass, was found to have no effect on the cast pressures (P > 0.05) (Table 2). Post hoc analysis of the effect of cast padding found significant effects on the cast pressure (Figs. 2, 3). Waterproof cast padding demonstrated significantly higher pressure readings (P < 0.05) at all time-points during sequential cast release except after stockinet release and elastic bandage application when synthetic cast padding demonstrated similarly elevated pressure readings. Cotton padding had the lowest pressure readings following cast bivalve, cutting of cast padding, and application of elastic bandage (P < 0.05).
DISCUSSION Although cast immobilization remains the recommended treatment intervention for many adult and pediatric orthopaedic conditions, it is not without potential complications. These complications include the risk of joint stiffness from prolonged immobilization, pressure sores and skin breakdown, thermal injury from cast placement, cast saw burns sustained during removal, and compartment syndrome.2,6,7 The most serious of cast-related complications is compartment syndrome. Volkmann8 first recognized the potential of tight bandaging to cause prolonged blockage in arterial flow, resulting in ischemia and the contracture that now bears his name. Bingold4 was the first to measure pressures after casting in a simulated forearm model,
FIGURE 2. Change in pressure at set time-points as a function of cast and padding type. Copyright
r
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright r 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
J Pediatr Orthop
Volume 00, Number 00, ’’ 2015
Effect of Casting Material on the Cast Pressure
TABLE 1. Results of Mixed-design Analysis of Variance Assessing Pressure Values as a Function of Different Study Time-points Condition Initial to bivalve Initial to cut pad Bivalve to cut pad Cut padding pressure Loose ace wrap pressure
F
P
45.55 3.80 42.69 3.80 4.28
< 0.001 0.007 < 0.001 0.007 0.004
finding an 80% decrease in pressure after bivalving. Garfin assessed the ability of cast valving to decrease intracompartmental pressures under plaster casts applied to dogs, finding a 65% reduction in pressure upon univalving a cast. An additional 10% decrease was found with cutting of the underlying cast padding.9 Additional studies have since investigated the impact of different materials on casting pressure, finding increased pressures with the use of fiberglass casting,10,11 as well as casting technique.10 No study to date has investigated the effect of different types of cast padding. We found significant higher cast pressures when using synthetic and waterproof cast padding, in comparison with cotton padding. These findings were unaffected by the type of cast applied. Similar to previous studies,1,4,9 we found a significant pressure drop after cast bivalve. A 75% pressure decrease occurred with the cotton padding group following cast bivalve, with an additional 10% decrease after the padding was released. The decrease in pressure after releasing the cast padding was more significant for the synthetic (20%) and waterproof padding groups (25%). The application of a loose elastic bandage after complete release of the cast elevated the cast pressure to a point that was significantly higher than the cast pressures after cutting the cast padding. The degree of pressure elevation varied based upon padding type with synthetic and waterproof cast padding groups demonstrating higher pressures than the cotton padding groups. It is important to recognize that the implementation of valving to a circumferential cast has not been prospectively shown to decrease the incidence of cast-related compartment syndrome. Schulte et al12 performed a randomized controlled trial of 100 pediatric patient requiring closed reduction for a forearm fracture. Patients were randomized into either a closed or valved circumferential semirigid cast. The authors found no significant difference in cast-related complications with only 1 patient
TABLE 2. Results of Planned Comparison of Cast Type at Various Study Time-points Conditions Initial to bivalve Initial to cut pad Bivalve to cut pad Lose ace to tight ace Cut padding pressure Loose ace wrap pressure
Copyright
r
FIGURE 3. Percentage of change in the cast pressure from initial pressure following cast bivalve and padding cut.
in the closed casting group requiring secondary splitting for lymphedema. In addition, the process of valving negatively affects the biomechanical strength of the cast construct.13 Limitations of this study largely reflect the experimental methods. Although we used human volunteers to include the viscoelastic nature of the soft tissues of the forearm that are difficult to reproduce with nonliving models, the model does not account for the soft tissue injury that accompanies acute fractures of the forearm. As such, our results may not extrapolate to the acutely injured forearm, however, our results fall within previously reported values. In addition, we did not incorporate the 3point molding technique commonly utilized with reduction and casting of acute forearm fractures, which has been shown to affect the cast pressure.7
CONCLUSIONS Although compartment syndrome is a rare complication following cast immobilization, it should be considered in all patients, particularly those who may be unable to alert the provider of the classic symptoms, such as the young or incapacitated. We demonstrate that 1 factor that should be contemplated is the casting material, with cotton casting padding demonstrating significant decreased pressure readings as compared with synthetic and waterproof cast padding. Bivalving a circumferential cast resulting in significant reduction in the cast pressure reading, and the additional release of the underlying cast padding allows for further decrease in pressure. The application of an elastic bandage to a released cast results in a small, but significant increase in the cast pressure compared with released cast padding. For the acutely fractured forearm fracture, consideration should be given for using cotton cast padding to better accommodate soft tissue swelling.
P
REFERENCES
0.52 0.23 0.21 0.31 0.23 0.73
1. Walker RW, Draper E, Cable J. Evaluation of pressure beneath a split above elbow plaster cast. Ann R Coll Surg Engl. 2000;82: 307–310. 2. Halanski M, Noonan KJ. Cast and splint immobilization: complications. J Am Acad Orthop Surg. 2008;16:30–40. 3. Mashru RP, Herman MJ, Pizzutillo PD. Tibial shaft fractures in children and adolescents. J Am Acad Orthop Surg. 2005;13:345–352.
2015 Wolters Kluwer Health, Inc. All rights reserved.
www.pedorthopaedics.com |
3
Copyright r 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Roberts et al
4. Bingold AC. On splitting plasters. A useful analogy. J Bone Joint Surg Br. 1979;61-b:294–295. 5. Younger AS, Curran P, McQueen MM. Backslabs and plaster casts: which will best accommodate increasing intracompartmental pressures? Injury. 1990;21:179–181. 6. Hutchinson MJ, Hutchinson MR. Factors contributing to the temperature beneath plaster or fiberglass cast material. J Orthop Surg Res. 2008;3:10. 7. Deignan BJ, Iaquinto JM, Eskildsen SM, et al. Effect of pressure applied during casting on temperatures beneath casts. J Pediatr Orthop. 2011;31:791–797. 8. von Volkmann R. Ischaemic muscle paralyses and contractures. 1881. Clin Orthop Relat Res. 2007;456:20–21.
4 | www.pedorthopaedics.com
J Pediatr Orthop
Volume 00, Number 00, ’’ 2015
9. Garfin SR, Mubarak SJ, Evans KL, et al. Quantification of intracompartmental pressure and volume under plaster casts. J Bone Joint Surg Am. 1981;63:449–453. 10. Davids JR, Frick SL, Skewes E, et al. Skin surface pressure beneath an above-the-knee cast: plaster casts compared with fiberglass casts. J Bone Joint Surg Am. 1997;79:565–569. 11. Marson BM, Keenan MA. Skin surface pressures under short leg casts. J Orthop Trauma. 1993;7:275–278. 12. Schulte D, Habernig S, Zuzak T, et al. Forearm fractures in children: split opinions about splitting the cast. Eur J Pediatr Surg. 2014;24:163–167. 13. Nielsen DM, Ricketts DM. Where to split plaster casts. Injury. 2005;36:588–589.
Copyright
r
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright r 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
