Evaluation of cast splitting on lower leg compartment pressures: a pilot study identifying the most effective splitting technique

S. Sambhwani, M. Dungey, P. Allen S. Kirmani

Introduction: Lower limb immobilisation with full casts is commonly used to manage fractures. There may be the need to split casts in an emergency, such as compartment syndrome, with no current consensus as to which technique is most effective in reducing pressure quickly.
Our study aims to compare the reduction in pressure across lower leg compartments using three different cast splitting techniques.

Methods: This study was done on a volunteer doctor. Pressure sensors were positioned at the anterior, posterior and lateral compartments. A single plaster technician applied below knee full casts with sequential layering and were allowed to dry as per manufacture instructions. Cast were split utilising three splitting methods; bivalve, tramline and single split and measurements taken when each layer was split. We compared results of ten repetitions for each splitting technique.

Results: When the cast was initially cut there were significant reduction in pressure with the bivalve split (20.6 ± 0.76 N) when compared to both the single split (26.8 ± 1.13 N, P < 0.001)  and tramline split (26.4 ± 0.90 N, P < 0.001). When the cast was spread there were significant reduction in pressure with the bivalve split (10.7 ± 0.83 units) when compared to both the single split (14.6 ± 0.85 N, P < 0.001) and tramline split (16.6 ± 0.77 N, P < 0.001). When the final layer of wool was released the pressure remained lower (statistically significant)  in the bivalve split compared to both single split and tramline split.

Conclusion: Our study demonstrates that bivalve cast splitting provided a more rapid reduction in pressure compared to other techniques across all three compartments. Our data shows that once down to skin, bivalve splitting continues to provide the lowest pressure compared to the other techniques. We recommend utilising bivalve when splitting a cast in an emergency.