Authors: James I. Boyd, III, MD, Montri D. Wongworawat, MD
Title: Comparison of Soft Tissue Disruption Caused by High and Low Pressure Wound Lavage Systems
Addresses: Loma Linda University, Department of Orthopaedic Surgery, 11234 Anderson Street, Suite A521, Loma Linda, CA 92354
Purpose: To investigate and quantify the amount of soft tissue injury caused by high pressure pulsatile lavage (HPPL), and to compare this with gravity flow low pressure lavage (LPL).
Methods: Forty sections of fresh ovine muscle harvested within four hours of euthanasia were divided for lavage by two methods—irrigation with the water stream directed in line (IL) with the muscle fibers as in cross section (n = 20), and directed across (AC) the fibers in a perpendicular fashion (n = 20). Each group was subdivided into two subgroups for type of delivery: HPPL (Surgilav Pulse, Stryker Instruments, Kalamazoo, MI) or LPL (standardized to 3 psi by hanging the bottle at a height differential of 215 cm). In addition, 10 control specimens were added, that received no irrigation. India Ink was mixed into the irrigant at a concentration of 5 cc per liter to allow gross visualization. The irrigation tip of either method was held 5 cm away from the muscle surface. Each specimen was irrigated with 500 cc of normal saline. The control group was simply placed in a basin of saline mixed with ink at the same concentration. After irrigation, the specimens were sectioned and randomized for gross examination by independent and blinded observers to assess depth of dye penetration and presence or absence of tissue disruption and maceration. Comparison of dye penetration between the five groups was performed using analysis of variance (ANOVA) combined with the Dunnett post hoc analysis to determine the groups with statistical significance. Chi-squared analysis was used to compare the groups with regards to the presence or absence of soft tissue disruption. Interobserver reliability was measured using the Pearson correlation coefficient and kappa analysis for depth penetration and for the presence or absence of soft tissue disruption, respectively.
Results: In terms of depth penetration, the HPPL specimens treated by AC and IL demonstrated a mean depth penetration of 4.7 mm and 15.6 mm, respectively. The LPL specimens showed 0.5 mm and 0.7 mm of ink penetration, respectively, and the control specimens had 0.2 mm. Both HPPL groups showed statistical significance (p < 0.0001), while there were no differences between both LPL groups and the control. Regarding the presence or absence of soft tissue disruption by gross visualization, similar results were found. All HPPL specimens showed gross disruption, whereas only one of the LPL specimens had a positive result. No control specimens had disruption. Comparing with the control, both HPPL groups showed a statistical difference (p < 0.0001). Interobserver reliability was excellent for both the continuous data of ink penetration and the nominal data of soft tissue disruption—r = 0.99, and k = 0.96, respectively.
Discussion: Adequate initial wound treatment is essential in the treatment of open fractures to minimize potential complications. While there is consensus that wound irrigation is an essential part of open fracture management, there is much variability in the type of irrigation delivery. These delivery systems can be differentiated into two main categories: high pressure and low pressure. HPPL has been shown to be more effective in removing devitalized tissue and bacterial contamination in both in vitro and in vivo studies. However, there is evidence that HPPL damages bone structure. In this in vitro study, the authors have extended this observation to include soft tissue. HPPL was shown to produce a significantly deeper soft tissue penetration while causing disruption in the soft tissue macrostructure.
Significance: The authors have shown that HPPL causes significant damage in the soft tissues. This adds to previous studies in the literature, which have demonstrated bone damages on both microscopic and macroscopic scales and a compromise in healing.