Proximity Injury by the Ultrasonically Activated Scalpel During Dissection By K.M. Kadesky, B. Schopf, J.F. Magee, and G.K. Blair Vancouver, British Columbia l The ultrasonically activated scalpel is a high-frequency oscillating instrument that is reported to have a decreased dispersion of energy to surrounding tissues during use. To determine if this effect is beneficial and safe to surrounding tissue, it was used on anesthetized adolescent swine to dissect the portal vein from the pancreas, the renal artery and vein from the renal hilum, the ureter from the retroperi- toneum, the aorta from the inferior vena cava and the common bile duct from surrounding tissue. Three-second contact to intestine and nerve roots was also performed. Wedge biopsy specimens of liver and spleen were per- formed. Dissection technique used was as desc,ribed by the company. Structures were dissected with electrocautery using similar techniques for comparison. Tissues were har- vested and placed in formalin for histological analysis. Dissection with the ultrasonically activated scalpel was simple, achieved excellent hemostasis, and did not appear to damage adjacent tissue. Microscopic analysis showed adven- ticial and media injury to vascular structures. The ureter and common bile duct demonstrated marked injury with regions of transmural coagulation. Nerve and small bowel did not appear to have much injury from the 3-second contact with the instrument. This study indicated that although the ultrasonically activated scalpel can ease dissection with good hemostasis, care must be taken to avoid injury to adjacent structures. Although its lateral energy dispersion may be less than that of cautery, it can still cause transmural necrosis to major structures. Copyright o 1997 by W.B. Saunders Company INDEX WORDS: Harmonic scalpel, tissue injury. T HE ULTRASONICALLY activated scalpel (Har- monic Scalpel, Ultracision Inc, RI [HS]) is one of the newest technologies in the surgical armament. By oscillating at 55,000 Hz over a 50 to loo-pm arc, it can cut through tissue and create local hemostasis.’ It is designed to cut with minimal injury to surrounding tissue.’ It is also possible to dissect along tissue planes without injury underlying tissue.’ The instrument accom- plishes both cutting and hemostatic functions without thermal energy and is felt to decrease the surrounding tissue injury during its use.2 Is there any significant injury From the British Columbia Chddre~~ S Hospital, Vancouver; British Columbia. Presented at the 28th Annual Meetrng of the Canadian Association of Paediatrlc Surgeons, Halifau, Nova Scotia. August 18-20, 1996. Address correspondence to Geoffrey K. Blail; MD, British Columbia Children’s Hospital, 4480 Oak St, Room A242, Vancouvei; BC, Canada V6H 3V4. Copyright o 1997 by WB. Saunders Company 0022.3468/97/3206-0019$03.00/O 878 to tissues isolated by this instrument? This study was performed to determine the extent of proximity tissue injury when using an HS during intraabdominal surgical procedures. MATERIALS AND METHODS Adolescent swine (previously used for studies in gastroesophageal reflux) were anesthetized using pentobarbital sedation and halothane anesthesia. Laparotomy was performed, and various structures were dissected using the HS at standard settings. Dissection with electrocau- tery (EC) was used for comparison. Wedge biopsy specimens of liver and spleen using HS and EC techniques were performed. The common bile duct was dissected from surrounding tissue with an HS. Portal vein was separated from pancreas with both HS and EC. Renal artery and vein were isolated from the surrounding renal hilar tissue. The aorta was separated from the inferior vena cava with HS followed by periaortic cautery dissection at a differeni level. Ureters were removed from the retroperitoneum by performing dissection parallel to the ureter along tissue planes. Lumbar nerve roots and small intestine were subjected to 3-second contact from either HS or EC then sharply excised and placed in formalin. At completion of each &section, tissue was harvested by sharp excision and placed in formalin. At completion of each dissection, tissue was harvested by sharp excision and placed in formalin for histologrcal assessment of cellular injury. Tissue damage was assessed using H&E staining. Criteria for tissue damage included depth of coagulation, evidence of inflammation, and loss of cellular architecture. Tissue damage was assessed in a blinded fashion. RESULTS Dissection through liver and spleen was subjectively easier with the HS and obtained better hemostasis. Dissection of the common bile duct and portal vein were easily performed with the HS with no visible evidelice of injury to the structures. Attempted cautery dissection using identical technique resulted in multiple venotomies and charring of the tissue. Dissection of the ureter was also technically easy with no visible evidence of injury. Separation of aorta from inferior vena cava *as easily performed with the HS with no gross evidence of vascular injury. Histological assessment of tissue injury demonstrated marked cellular destruction in specimens dissected with HS as well as with EC. HS-dissected common bile duct demonstrated circumferential injury with 80% thickness of the bile duct wall being coagulated in most areas and 30% having transmural necrosis. Ureter specimens dis- sected with the HS demonstrated marked injury with transmural coagulation throughout. Ureter specimens from the EC group as well had marked transmural injury that was graded as subjectively less than the HS group. Journal of Pediatric Surgery, Vol32, No 6 (June), 1997: pp 878-879