Decreased Surgical Time with a Vessel Sealing Device Versus a Surgical Stapler in Performance of Canine Splenectomy

Introduction

Splenectomy in the dog is performed for many reasons, including trauma, torsion, neoplasia, and autoimmune disease. Naturally occurring splenic disease in dogs is often associated with highly vascularized networks of splenic, short gastric, omental, and mesenteric vessels. Traditional splenectomy techniques rely on ligation of either the hilar vessels or splenic and short gastric vessels.^1–4 Ligation techniques can be tedious and time consuming, potentially allowing more hemorrhage to occur, and may result in increased anesthesia times in compromised patients. Use of stapling devices can decrease procedural time for performance of a splenectomy.^2,4,5 However, minimal tissue handling is required to avoid dislodging the staples.⁶ Other disadvantages of stapling include leaving nonabsorbable implants in situ that may act as a nidus for adhesion formation, safe hemostasis is limited to vessels ≤ 4 mm in diameter, staples tend to catch on laparotomy sponges, and cartridge jamming can occur.^2,4,7–9

Vessel sealing devices are now readily available and reportedly provide effective hemostasis for general surgery and laparoscopic procedures. One proprietary vessel sealing device^a relies on pressure and energy to permanently fuse vessels by melting the collagen and elastin in the vessel wall, resulting in a plastic-like seal.^10–12 That device measures tissue impedance and delivers only the power needed for tissue sealing, thus reducing collateral heat damage to surrounding tissues.^8,10,11,13 Advantages of vascular sealing devices include reduced smoke plumage compared with other electrocautery devices, the ability to seal vessels up to 7 mm in diameter, and maintenance of a strong seal providing vessel bursting strength up to three times normal systolic pressures.^7,8,11,12,14 Use of vascular sealing devices is relatively straightforward and does not require implants for vessel ligation. In previous studies, a vessel sealing device reportedly reduced surgical time, decreased intraoperative and postoperative blood loss, and was comparable in price to ultrasonic-activated scalpels.^15–18

The purpose of this study was to retrospectively analyze and compare use of a surgical stapling device with a vessel sealing device to perform splenectomy in dogs. The authors hypothesized that surgical outcomes of dogs with splenic disease undergoing a splenectomy removed with the assistance of a vessel sealing device would be comparable to those of surgeries employing a stapling device^b and that splenectomy time would be significantly less for the vessel sealing device group.

Materials and Methods

Results

Surgery and Outcomes

Five surgeons performed surgeries included in the study. Two were board-certified by the American College of Veterinary Surgeons, one was a surgical resident, and two were emergency clinicians.

All patients survived the surgery, and none required a second surgery. There were 55 liver biopsies, 14 incisional gastropexies, and 11 dogs had both of those procedures performed in conjunction with the splenectomy. The most common complication encountered was premature ventricular contractions in 29 patients (40%), but none of the affected dogs required treatment. Intraoperative hypotension (defined as systolic pressures < 100 mm Hg for > 1 reading) was the second most common complication, detected in 22 patients (30%).

The preoperative mean PCV was 33.6% ± 9.4% and the postoperative mean PCV was 30.0% ± 8.6%. Nineteen patients (26%) received a transfusion, 47% of those postoperatively. Eight patients (four hemangiosarcomas, two nonhemangiosarcomas, and two nonneoplasias) were either euthanized or died in the hospital prior to discharge. Mean hospital stay was 2.6 days ± 0.8 days (range, 1–4 days). No significant interactions between device group and the aforementioned factors were found.

There were 39 dogs treated with the vessel sealing device and 33 with the stapling device. The vessel sealing device group had a statistically significant shorter surgical time (mean surgical time, 58.4 min ± 3.3 min; median time, 60 min; range, 22–131 min) than that of the stapling device (mean surgical time, 66.9 min ± 2.4 min; median time, 66 min; range, 40–100 min). Results of age, preoperative PCV, surgical time, anesthetic time, postoperative PCV, and days of hospitalization between the device used and disease diagnosis have been presented in Table 1. After adjustment for age (employing appropriate transformations to account for the nonlinearity between age and the log hazard rate^d), sex, weight, surgeon experience, Diplomate status, number of uses of each device/individual, complications, pre- or postoperative PCV, performance of gastropexy and/or liver biopsy, liver histopathology, splenic histopathology, and mass size, time of completion of surgery was faster in the vessel sealing device group (hazard rate ratio, 2.06; 95% confidence interval, 1.14–3.73; P = 0.017). There were no significant interactions between device group and any other factors evaluated.

TABLE 1 Mean Comparison of the Age, Pre- and Postoperative PCV, Surgical and Anesthetic Times, and Hospital Stay Between the Subsets of the Vessel Sealing and Stapling Devices

HSA, hemangiosarcoma; PCV, packed cell volume.

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Discussion

This study proved a statistically significant shorter surgical time was required with use of a vessel sealing device in comparison with a traditional stapler for removal of the spleen in the dog. This was true despite the experience/training of the surgeon, the performance of other surgical procedures, and histopathologic nature of the splenic disease.

In this study, the sample population was chosen from medical records of splenectomy patients based on surgical procedures performed. Neoplastic lesions accounted for 38 of the cases (52%), with 30 hemangiosarcomas and 8 other tumors. Nonneoplastic lesions were found in 34 of the spleens (48%), with hematomas accounting for 24 of those (Table 2). The distribution of splenic diagnoses was consistent with previously reported studies.^19–22

TABLE 2 Total Number of Splenectomies Performed with the Vessel Sealing Device and Stapler

HSA, hemangiosarcoma.

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The current study included dogs that had liver biopsies and gastropexies in conjunction with splenectomy, as those are common adjunctive surgeries. Interestingly, there were more gastropexies and liver biopsies performed in the vessel sealing device group (n = 12 and n = 36, respectively) than in the stapler group (n = 2 and n = 19, respectively), yet the overall surgical time was reduced in the vessel sealing device group.

Two recent studies have examined the efficacy of vascular sealing devices in dogs for splenectomy.^14,23 One study reported effective hemostasis of vessels up to 7 mm in diameter and recommended measurement of the splenic vessels prior to ligation. The authors also recommended performing three overlapping seals on the major splenic artery and two on the splenic vein with transaction on the distal most seal.¹⁴ The study authors’ recent clinical experience supports Rivier and Monnet’s recommendations that a vessel sealing device can achieve effective hemostasis for the splenic artery and vein.¹⁴ Tension on the splenic artery and vein, either by handling or from the weight of the spleen, should be minimized while using the vessel sealing device as tearing can occur at the vascular seal. The study authors also found that ligation of multiple vessels can lead to char buildup on the device jaws leading to adhesion of the tissues to the instrument. The authors recommend frequent cleaning of the jaws to prevent char buildup.

In the authors’ experience, multiple uses of the disposable vessel sealing devices were possible with proper use and maintenance, and the authors found that approximately 10 uses of the disposable devices were possible. Wear on the cutting tool and degradation of the insulation on the jaws were the most common problems the authors encountered, requiring instrument replacement. The cost of the generator unit was a limiting factor. In comparison, stapling device replacement cartridges and disposable hand pieces have a similar cost/patient over time.

As with all retrospective analysis, there are limitations to this study. Device selection was not randomized among individuals. Instead, the use of device was confounded by time period. Prior to July 2006, only the stapling device was used, and following that date, the vessel sealing device was almost exclusively used due to perceived speed and safety. Prior to July 2006, surgeons exclusively used the stapling device; however, confounding by indication was not present. Data were evaluated for the potentially confounding effects of splenic diagnosis, mass size, and need for gastropexy. Although it seems unlikely that there were other factors that could have been substantial confounders, that possibility cannot be ruled out, and uncontrolled confounding variables in a nonrandomized study could lead to biased effect measure estimates, too narrow confidence intervals, and inappropriately low P values.

Conclusion

This study demonstrated that the vessel sealing device was suitable for performing splenectomy in dogs in less time than the stapling device, thereby potentially reducing risk to the patient. The operator should be familiar with potential vessel size limitations for effective and safe hemostasis using the vessel sealing device.