A New Vessel Sealing System:

Seal Integrity and Histology

Robert D. Tucker PhD, MD

The University of Iowa

Department of Pathology

Department of Biomedical Engineering

Study Objective

• The study examines the efficacy of a new electrosurgical system by Live Tissue Connect (LTC) for the sealing of vessels

• Efficacy was accessed by:

- Sealed tissue-to-electrode sticking

- Vessel burst strength

- Histological assessment of thermal

damage

LTC Bipolar Generator

LTC Bipolar Forceps

In Vivo Experiments

• Sus Scrofia pigs maintained at a surgical

plane by inhalation of isoflurane

• 34 arteries from 2 to 8 mm in diameter were

sealed

Vessel Sealing

Sealed Vessel

Sealed Tissue-to-Electrode Sticking

• Tissue sticking measured on a scale: 0 (no adherence) to 4 (tissue attached to both jaws)

• Results

- Virtually no sticking during sealing

- Average sticking SD = 0.06 0.14

Vessel Burst Pressure

• Sealed vessels removed

• Vessel was infused with saline by a constant

flow microprocessor controlled syringe pump

• Pressure was held at 360 mm of Hg for 10 sec

• Burst pressure was measured with a digital

monometer

Vessel Burst Pressure

Vessel Diameter

( in mm)

Average SD

(in mm of Hg)

2 to 3 916 79

4 to 5 1008 126

6 to 7 917 82

8 640 71

Vessel Burst Pressure

• 32 seal average = 942 mm of Hg

• Burst pressure is over 7 times normal

systolic blood pressure

Question ?

• Acute seal pressures are very high, but..

• Is there thermal damage to the remaining

patent vessel wall (the non sealed vessel

wall) which could led to necrosis?

Answer

• Compare seals made with: the LTC system

and the commercially available Gyrus

system

• Analyze histology of the seals for thermal

damage to the unsealed portion of the vessel

Histological Analysis

• Vessels were placed in 10 % neutral

buffered formalin for at least 24 hours

• Vessels were sectioned longitudinally

through the seal

• Thermal damage accessed using a calibrated

ocular with standard light microscopy and

polarized light microscopy

Histology Measurements

Polarized Light

Tissue Under Forceps Jaw

Transition Area

Histology Measurements

Histology Measured Distances

Note: a positive D represents no damage to the

remaining patent vessel wall

Company Thickness of

Seal, T

Thermal

Damage, D

LTC 0.72 0.04 0.33 0.05

Gyrus 0.85 0.07 0.11 0.06

Histology Measured Distances

differences significant at p = 0.025

Company

Number of

Negative D

ValuesN

LTC 4 26

Gyrus 15 25

Note: a positive D represents no damage to the

remaining patent vessel wall

Conclusions

• The LTC system produces consistent and

reliable seals with super physiological

strength.

• The LTC vessel sealing occurs with

virtually no electrode sticking.

• The LTC sealing system confines most of

the thermal damage to the area under the

electrode and produces little thermal

damage to the remaining vessel