New bipolar tissue ligator combines constant tissue compression and temperature guidance: histologic study and implications for treatment of hemorrhoids

Abstract

Background: Several minimally invasive technologies are available to treat common soft tissue lesions including symptomatic hemorrhoids. The use of energy to deliver heat and coagulate target lesions is commonly practiced. This study compares the histologic effects produced on intestinal tissues by two energy-based systems which employ different approaches of heat delivery.

Methods: TWO HEAT DELIVERY SYSTEMS WERE EVALUATED IN VIVO IN A SINGLE PORCINE SUBJECT: infrared coagulator and bipolar tissue ligator utilizing constant tissue compression and temperature guidance. Eighteen treatment sites divided into three groups of six were assessed. Treatment site temperature was measured and the effects of thermal treatment in the mucosa, submucosa, submucosal vessels, and muscularis layer were scored. Lateral thermal spread beyond the energy application site was also assessed.

Results: Treatment site temperatures were much lower in the bipolar ligator group than in the infrared coagulator group. The mucosal and submucosal tissue changes observed in tissues treated with infrared energy and bipolar energy at 55°C were similar. Both the mucosal and submucosal tissue changes with bipolar energy at 50°C were significantly less.

Conclusion: Both devices achieved similar histologic results. However, the unique design of the bipolar ligator, which allows consistent capture, constant compression, and temperature monitoring of target tissue, accomplished the desired histologic changes with less muscular damage at much lower temperatures than the infrared coagulator. The use of bipolar ligation could offer clinical advantages such as reduced patient pain and a minimized chance of heat-related collateral tissue damage.

Keywords: bipolar ligator; internal hemorrhoids; ligation; tissue manipulation.

Figure 1

Gross comparative mucosal changes in three rows of applications: IRC (IR) and HET with final tissue temperatures of 50°C and 55°C. Abbreviations: IRC, infrared coagulator; HET, HET Bipolar Ligator.

Figure 2

A photomicrograph (mag 40×) from the HET55 group. Notes: The treated area is between the arrows and marked as T; the normal area is marked as N. Note the thinning of the mucosa by 25% to 50% compared to the normal area. There is also a loss of basophilic staining in the mucosa and the loss of crypt glands in the treated area. Abbreviations: HET55, HET Bipolar Ligator at 55°C; T, treated area; N, normal area.

Figure 3

A photomicrograph (mag 40×) from the HET50 group. Notes: The treated area is to the left of the arrows and marked as N. Note the thinning of the mucosa by 25% compared to the normal area. There is also a loss of basophilic staining in the mucosa and the loss of crypt glands in the treated area. Abbreviations: HET50, HET Bipolar Ligator at 50°C; T, treated area; N, normal area.

Figure 4

A photomicrograph (magnification 100×) from the IRC group. Notes: The treated area is below the arrows and marked as T; the normal area is marked as N. Note the loss of basophilic staining in the mucosa and the loss of crypt glands in the treated area. Abbreviations: IRC, infrared coagulator; T, treated area; N, normal area.

Figure 5

A micrograph (mag 40×) of a representative sample from the HET55 group. Note: The treated area is below the arrows and marked as T; the normal area is marked as N. Note the thinning of the submucosa compared to the normal area. There is also hemorrhage in the mucosa, and vascular damage and congestion in the submucosa in the treated area. Abbreviations: HET55, HET Bipolar Ligator at 55°C; T, treated area; N, normal area.

Figure 6

A photomicrograph (mag 400×) from the IRC group depicting three vessels in the submucosa with congestion. Notes: The nuclei in the vessel walls demonstrate thermal damage and are condensed and hyperchromic. The arrows point to several spots of vacuolization caused by heat. Abbreviation: IRC, infrared coagulator.

Figure 7

A photomicrograph (mag 40×) of the application of the HET device at 55°C viewed with polarized light. Notes: The treated area is above the arrows and marked as T; the normal area is marked as N. As collagen is heated, the molecule loses its isotropic conformation and becomes anisotropic; when viewed under polarized light the isotropic collagen appears bright and denatured collagen is dark. The normal isotropic collagen molecule appears bright and is represented in the lower area as several bands; however, closer to the treatment application and in the treated area, there is denaturation of collagen (loss of brightness). Abbreviations: HET, HET Bipolar Ligator; T, treated area; N, normal area.

Figure 8

A photomicrograph (mag 200×) of the application of the HET device at 55°C. Notes: The submucosa is marked SM and the muscularis is marked M. The arrows point to the slight muscle damage, estimated to be a few cell layers thick. Abbreviations: SM, submucosa; M, muscularis.