Electromagnetic Energy Sources in Surgery

Development and application of a spray tip that enables electrocoagulation of a variety of tissues

BACKGROUND

Spray hemostasis is possible using a high-frequency power source from the tip of an electric scalpel; however, the difficulties regarding the uniformity and rapidity of the hemostasis surface remain. This study reports the development of a novel electrocoagulation device tip that can be used in endoscopic and robotic surgeries and can quickly coagulate and hemostat and easily adjust the extent of cauterization and hemostasis while minimizing the depth of thermal injury.

METHODS

The safety and efficacy of the hemostatic device were verified in a porcine model. A liver surface transection was conducted in vivo and the rapidity of the hemostatic effect of the device was observed. An extracted stomach, kidney, and liver were cauterized ex vivo by three operators with different surgical skills and the effects were analyzed pathologically. In addition, a sacrificed pig cadaver was used to achieve hemostasis at a renal transection site using the multi-spray endoscope tip.

RESULTS

An increase in the number of tip terminals expanded the cauterization surface and shortened the cauterization time. In parenchymatous organs, uniform cauterization was possible without increasing the depth of thermal injury. The cauterization depth did not depend on the operator's skill, and the spray coagulation was safe. The variable spray tip allowed for simple hemostasis during open and laparoscopic surgeries.

CONCLUSIONS

This novel electrocoagulation device tip can be developed as a forceps that can change the spray range and can be used during laparoscopic and robotic surgeries.

Incidence of and risk factors for surgical site infection following canine limb amputation

OBJECTIVE

To determine the incidence of and risk factors for surgical site infection (SSI) following canine thoracic and pelvic limb amputations.

STUDY DESIGN

Retrospective, multicenter study.

ANIMALS

Dogs (n = 248).

METHODS

Medical records were reviewed for preoperative, intraoperative, and postoperative variables including indication for amputation, amputation type, method of muscle transection, duration of surgery and anesthesia, and wound classification. Follow up was ≥30 days or until SSI development. Logistic regression and Fisher's exact tests were used to compare SSI incidence to variables of interest.

RESULTS

The incidence of SSI was 12.5% for all procedures and 10.9% for clean procedures. Factors increasing odds of SSI were muscle transection with a bipolar vessel sealing device (P = .023 for all procedures, P = .025 for clean procedures), procedure classified as other than clean (P = .003), and indication for amputation of bacterial infection (P = .041) or traumatic injury (P = .003) compared to neoplasia.

CONCLUSION

Use of bipolar vessel sealing devices for muscle transection increased the odds of developing an SSI whereas use of electrosurgery and/or sharp transection did not. Dogs with surgical sites that were other than clean, or with bacterial infection and/or traumatic injury were also at increased odds of SSI.

CLINICAL SIGNIFICANCE

Use of electrosurgery or sharp transection for muscle transection should be considered rather than use of bipolar vessel sealing devices to decrease odds of SSI in dogs undergoing limb amputation. Further studies across a variety of procedures are needed to validate these findings given the increasing popularity of these devices in veterinary medicine.

Comparative Morphological Effects of Cold-Blade, Electrosurgical, and Plasma Scalpels on Dog Skin

The aim of the present study was to evaluate the histological results of the Onemytis^® plasma surgery device with Airplasma^® technology. We compared the efficacy and the effect on tissues of the new plasma electrocoagulation system with electrosurgery and a scalpel blade. Samples of healthy skin tissue from four dogs that underwent mastectomy were evaluated. Three different incision modes were used, i.e., a cold blade, electrosurgery, and the Onemytis^® plasma scalpel were evaluated histologically to assess invasiveness and tissue injuries at different distances from the cutting surface. The histological examinations showed moderate necrosis caused by Onemytis^®, compared to the use of the more invasive electrosurgery, which induces thermal damage that extends beyond 1000 µm. Our study shows that the use of the plasma scalpel reduces the extension of the thermal lesion on the skin compared to an electrosurgical scalpel.

Performance and microbiological safety testing after multiple use cycles and hydrogen peroxide sterilization of a 5-mm vessel-sealing device

OBJECTIVE

To evaluate the functional and microbiological safety of a single-use laparoscopic vessel-sealing device in a multiuse setting.

STUDY DESIGN

Ex vivo study.

SAMPLE POPULATION

Twelve 5-mm LigaSure Maryland jaw devices.

METHODS

Handsets underwent repeated test cycles until failure. The handset packaging was opened, and handsets were agitated in phosphate-buffered saline (PBS). The PBS was removed, centrifuged, and submitted for culture. Canine ovariectomy was simulated on cadaveric tissue, after which vascular seal quality was evaluated by pressure testing of sealed porcine carotid arteries. The handsets were cleaned and sterilized with hydrogen peroxide gas and repackaged.

RESULTS

Mean ± SD cycles to failure was 7.7 ± 2.8, with a minimum of 4 and a maximum of 12 use cycles achieved. Eleven of the 12 handsets failed by failure of handset activation after depression of the activation trigger. Only 1 handset failed to hold an adequate vascular seal under 300 mm Hg of pressure. No handset exhibited positive bacterial culture at any cycle.

CONCLUSION

The sterilization method used in this study resulted in an excellent microbiological safety profile. Most of the handsets failed by activation button failure.

CLINICAL SIGNIFICANCE

Under the conditions of this study, hydrogen peroxide sterilization achieved microbiological safety. Handsets can successfully be reused until activation button failure without negative effects on the vascular seal or increased risk of infection to the patient.

Healing of canine skin incisions made with monopolar electrosurgery versus scalpel blade

OBJECTIVE

To determine the influence of monopolar electrosurgery in cutting mode set at 10, 20, or 30 W on surgery time, hemostasis, and healing of cutaneous wounds compared to scalpel incisions.

STUDY DESIGN

Randomized blinded control trial.

ANIMALS

Dogs (n = 15).

METHODS

Four skin incisions were created on either side of the dorsal midline with a scalpel, or monopolar electrosurgery at 10, 20, and 30 W. Surgical time and incisional bleeding were measured. Each incision was assessed daily for edema, erythema and discharge, and complications. Healing was evaluated via histology at 7 days. Results were analyzed for significance at P ≤ .05.

RESULTS

Surgical time and hemostasis were improved in all electrosurgery groups. Erythema was reduced in all electrosurgical incisions for days 1-4, but was greater in wounds created via electrosurgery at 20 W than those made with a scalpel blade by day 7. No difference was noted in the degree of edema or presence of wound discharge. All histologic variables of tissue healing were lower in electrosurgical incisions than scalpel incisions (P < .001). Ten incisional complications occurred, all associated with electrosurgery.

CONCLUSIONS

The use of monopolar electrosurgery at 10, 20, and 30 W in a cutting waveform improved hemostasis and surgical time when incising canine skin, but delayed healing and increased complications within the first 7 days compared to scalpel incisions.

Resection and Primary Closure of Edematous Glossoepiglottic Mucosa in a Dog Causing Laryngeal Obstruction

An approximately 22 mo old male neutered English bulldog was evaluated for acute onset of dyspnea with suspected brachycephalic obstructive airway syndrome (BOAS). Laryngoscopic exam revealed diffuse, severe edema and static displacement of redundant glossoepiglottic (GE) mucosa causing complete obstruction of the larynx and epiglottic entrapment. Static displacement of the GE mucosa was observed and determined to be the overriding component of dyspnea in this patient with BOAS. Resection and primary closure with two separate, simple continuous sutures of the GE mucosa were performed. Resection and primary closure of the GE mucosa resolved the acute onset of dyspnea in this patient. Surgical correction of the stenotic nares, elongated soft palate, and everted laryngeal saccules were performed under the same anesthetic procedure. Static displacement of the GE mucosa may occur in patients with BOAS. Surgical resection and closure of the GE mucosa resolved this patient's dyspnea and is recommended in airway obstruction. It remains to be determined if primary closure and subsequent tensioning or scar tissue of the GE mucosa results in further complications related to restricted epiglottic movement.

Thermal tissue change induced by a microwave surgical instrument in a rat hepatectomy model

BACKGROUND

Microwaves exhibit great potential in tissue heating, which causes effective coagulation. Using this energy, we have developed the microwave coagulation surgical instrument (MWCX) for clinical application. Here, we characterized the impact of MWCX on tissues including heating property, tissue change, and spread of thermal injury.

METHODS

Hepatectomy was performed with MWCX using a rat model. The resections were completed using various energy levels and powers. Tissue temperature during radiation was recorded. Tissue change and lateral thermal injury (LTI) was assessed immediately, 7 days, 3 months, and 6 months after resection.

RESULTS

All cutting and hemostasis procedures were successfully accomplished. Major histologic findings consisted of deformation or destruction of hepatocytes, tissue edema, and peripheral hemorrhage. At various energy levels, 200 to 1000 J, the tissue was heated up to approximately 80°C to 140°C causing 2.7- to 6.5-mm LTI on the 7th day. LTI was then decreased gradually in the following term. At certain energy levels, the application of neither 20 W nor 40 W induced significant difference in both heating and LTI.

CONCLUSIONS

MWCX achieved effective tissue coagulation with relevant tissue injury, and it should be a good candidate for clinical application.

Laparoscopic treatment of persistent inguinal haemorrhage after prescrotal orchiectomy in a dog

A one-year-old male Jack Russell terrier developed a prescrotal haematoma after elective orchiectomy. When surgical exploration failed to locate the responsible vessel and conservative therapy (applying a pressure bandage) was not successful in stabilising the dog, abdominal laparoscopy was performed. The haemorrhage originated from the spermatic cord in the inguinal canal bilaterally. After retracting the spermatic cord into the abdomen, haemostasis was performed using a vessel-sealing device. The prescrotal haematoma was removed and the dog made an uncomplicated recovery.

Use of the Ligasure vessel-sealing device for thoracoscopic peripheral lung biopsy in healthy dogs

OBJECTIVE

To evaluate the use of a bipolar vessel-sealing device for peripheral lung lobe biopsy in healthy dogs.

STUDY DESIGN

Experimental study.

ANIMALS

Mature female hound dogs (n = 6).

METHODS

Thoracoscopic access was obtained by placement of a subxiphoid telescope portal with instrument portals at the right 4-6th intercostal spaces and the left 10th intercostal space. The 10-mm Ligasure Atlas device was used to collect a biopsy specimen from the periphery of the left cranial lung lobe. Dogs were recovered from anesthesia. Histologic evaluation was used to characterize the effect of biopsy technique on pulmonary tissue. Thoracic radiography was performed at 1, 2, 4, and ∼180 days to evaluate for air leakage or other postoperative complications.

RESULTS

Lung specimens were collected without complications. Postoperatively, 1 dog had some residual pneumothorax thought to be secondary to incomplete thoracic evacuation of air postoperatively. No evidence of air leakage was detected at any time point. Histologically, specimens had 3 distinct zones: a crush zone representing the tissue within the jaws of the device, a transition zone of thermally damaged parenchyma, and beyond that a viable zone of normal parenchyma.

CONCLUSION

From these limited data, it appears that the Ligasure Atlas vessel-sealing device can be used for peripheral lung biopsy in healthy dogs. Further studies are required to evaluate the efficacy of the device in dogs with parenchymal disease.

Evaluation of EnSeal®, an adaptive bipolar electrosurgical tissue-sealing device

Relatively few, and inconsistent, data are available in the literature about the properties of EnSeal®, an electrosurgical tissue-sealing device. For this reason, we conducted control safety tests on experimental pigs. The mean burst pressure of sealed vessels (2-7 mm in diameter) proved to be 873.89 ± 120.57 mmHg (n = 60). Surface temperature increased to 69.25 ± 0.98 °C in average (n = 22). The mean diameter of the collateral microscopic thermal injury zone was found to be 0.28 ± 0.04 mm, and it did not show significant differences among the groups of tissues studied (n = 183). During our studies, the device worked reliably and met the relevant requirements in all cases. It can be established that EnSeal® enables high-safety clinical interventions at high blood pressure values, in different tissues and even at sites adjacent to heat-sensitive tissues, and thus it paves the way for new operative solutions in both human and veterinary surgery. In our opinion, the discrepancies between data reported in the literature arise from differences in the design of studies and in the designated limit values. To ensure standardisation, we recommend the use of the nitroblue-tetrazolium chloride/lactate dehydrogenase (NBTC/LDH) enzyme histochemical technique for studying thermal injury induced by the different performance levels and application times of devices operating with electromagnetic energy.

Laparoscopic cryptorchidectomy and ovariectomy in standing horses using the EnSeal® tissue-sealing device

In the present series of cases, 8 laparoscopic cryptorchidectomies and 4 laparoscopic ovariectomies were carried out in sedated standing horses. Sedation involved a lesser anaesthesiological risk than does general anaesthesia. As compared to laparotomic exposure, the minimally invasive laparoscopic intervention provided better visualisation, shorter operative time and faster recovery. The blood vessels supplying the testes and ovaries and the suspensory ligaments of the organs were sealed and cut with EnSeal®, an adaptive bipolar electrosurgical blood vessel- and tissue-sealing device. The clinical use of the blood vessel- and tissue-sealing device proved to be successful in all cases. Gradual separation of the intact tissue from the treated, compacted, dehydrated and homogenised tissue areas and occlusion of the lumen of blood vessels treated with the device could be observed in all histological sections. To the best of our knowledge, this is the first report on the use of EnSeal® for laparoscopic cryptorchidectomy and ovariectomy in horses.