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Surgical cautery revisited
Surgical Cautery Revisited
Kevin M. Keenan, MD, Charlottesville, Virginia George 1. Rodeheaver, PhD, Charlottesville, Virginia John G. Kenney, MD, Charlottesville, Virginia Richard F. Edlkh, MD, PAD, Charlottesville, Virginia
The ideal surgical knife incises tissues without bleeding and does not interfere with wound repair or resistance to infection. The control of bleeding that occurs when living tissues are cut is a very important consideration in massive excisional operations, such as soft tissue tumors and debridement of third degree burns. The attendant blood loss often poses a major problem and may be a serious threat to the patient’s life. If these operative procedures could be conducted with markedly lessened blood loss and without significant local adverse effects, it would shorten the length of the operative procedure and eliminate the need for blood transfusions. A new hemostatic scalpel has been invented by Shaw to control the bleeding between the cut edges of the tissue [I]. This scalpel blade resembles conventional scalpel blades, except that it can be heated and its temperature controlled within narrow limits. Cutting is accomplished by the blade’s sharp edges and hemostasis results from the direct transfer of heat from the blade to the adjacent tissue during its passage through the tissue. The purpose of our study was to assess the effect of this scalpel on the healing of the wound and its resistance to infection. Material and Methods The new hemostatic scalpel used in this study is similar
in size and shape to a no. 15 blade. The scalpel handle is connected to a controller unit that provides a pulsed direct current to heat the scalpel to an elevated temperature ranging from 110 to 2WC. The controller senses and powers the microelectronic circuitry in the scalpel blade to maintain the desired temperature. Since the patient is From the Universityof Virginlal3umCenter and Departmentof PlasticSurgery, UniversityOf Virginia Schoolof Medicine,Charlottesville,Virginia. Requests for reprints shouldbe addressedto Richard F. Edlich, MD. Universityof Virginiaschool of Medicine,Box 332, Char!&tesvlile,Vlrginla 22909.
018
insulated from the electronic parts of the scalpel, a patient grounding pad is not needed. Blade temperatures of 160 to 160°C are often used clinically to limit bleeding during excisions or.incisions. A temperature of 114% is sufficient to control bleeding to some degree. Since the cutting edge of the hemostatic scalpel is similar to that of a conventional scalpel, cutting can be accomplished without the use of heat. Since hemostasis results from the direct transfer of heat from the edge of the scalpel, an unheated control scalpel has no hemostatic effect. Experimental design: The experimental model utilized in this study is reliable and reproducible in day-to-day assessment, and is also susceptible to replication in other laboratories. The albino guinea pig was chosen because of its availability and its susceptibility to infection caused by the pyogenic bacteria most commonly responsible for wound infection in human subjects. Hartley guinea pigs that weighed 300 to 350 g were caged individually and given food and water ad libitum during the period of study. The animals were anesthetized with pentobarbital admiitered intraperitoneally. On the day of the operation, the hair on the back of each animal was clipped with electric clippers. The remaining hair was then removed with a depilatory, and the operative site was washed with an iodophor solution and isolated with sterile drapes. Under aseptic conditions, two different techniques were employed to make separate incisions, 3 cm in length, parallel and equidistant from the vertebral spine, that extended through the panniculus carnosus down to the fascia. One incision was made by a scalpel heated to 120°C, and the other incision was made by a control scalpel of the same type that was unheated. A new scalpel blade was used to make each incision. The force applied to the scalpels was sufficient to cut through the skin with one stroke. The rate at which the heated scalpel cut through the skin was sufficient to limit the relative magnitude of blood loss from the wound as compared with the rate of blood loss due to the unheated scalpel. In the wound made by the unheated scalpel, pressure was applied to the wound site with gauze sponges to secure hemc&asis. Sites in which the heated and unheated scalpels were employed were
The American Joumal d Surgery
Surgical
cautefy Revlslted
3.25 f2.18
HOT SCALPEL
CONTROL SCALPEL
randomly assigned for each animal The animalswere then randomly divided into two different groups. In one treatment group, an inoculum of 100,000 Staphylococcusaureus was introduced into each wound. This level of bacterial contamination does not result in infection unless the resistance of the wound to infection is impaired.Five minutes after bacterial contamination, the wound edges were approximated by microporous tape. In the other group of animals without bacterial contamination, closure was accomplished by tape 10 minutes after wounding. In the animals with wounds subjected to bacterial contamination, the inflammatoryresponsesand concentration of bacteria were recorded 4 days after wounding. Tbe infknm&ry responsesasses& were wound induration and the presence of purulent exudate. Induration of the wound was determined by palpating its middle with the gloved finger on the fourth postoperative day. Tbe indurated margin at the middle of the wound was measured in millimeters. After each measurement,tbe wound was opened and inspected for evidence of a purulent exudate. In each wound, an estimate of tbe number of viable bacteriaon the wound surfacewas made. After swabbingthe length of the wound with a sterile cotton-tipped applicator, it was immersed in a glasstube containing 5 ml of 0.85 percent saline solution. The tube was then placed on a Vortexe mixer for 1 minute. The number of bacteria suspended in the saline solution was quantitated by standard microbiologic serial dilution and plating techniqu8s. The results were reported as the average logarithm of the bacterial count since it more accurately reflected the logarithmic growth of the organism. Ah r8suhs w8r8 subjected to statistical analysis utilizing a 95 percent confidence coefficient as a criterion of significance. Quantitative estimates of the number of bacteria and the induration measurements were analyzed using the Student’s t test for paired differences. Significance of the gross infection score was d8termined by the Wilcoxon two-sample rank sum test. In the animals with wounds that were not subjected to bacterial contamination,
voknw 147, Jlmn 1984
HOT SCALPEL
CONTROL SCALPEL
the wound tensile strength was recorded 15 days after wounding. The paravertebral wounds were excised with a generous margin of surrounding skin. Strips of skin of identical width (0.8 cm) and length (3.5 cm) were excised transversely across the middle of the wound. The breaking strength of the wound was then determined by attaching the ends of the wound to a continuous drive motor with a screw-gear advance. The drive motor was attached to a strain gauge that was electrically connected to a HewlettPackard’s recorder through an amplifier system. As the drive motor pulled the clip at a rate of 8.8 cm/min, the strain gauge recorder system provided a measure of the applied force necessary to disrupt the wound. Tensile strength was calculated for each wound by dividing the breaking strength value by the thickness of the test strip. The skin thickness was determined by a dial micrometer after the excised skin had been stretched back to its original size before excision. The significance ofthe tensile strength measurements for each wound was determined using the Student’s t test for paired differences.
Results The heated scalpel damaged the wounds’ resistance to infection when compared with the unheated scalpel. After bacterial contamination with a subinfective dose of inoculum, the inflammatory response of wounds made by the hot scaIpo1 was significantly greater than that made by the unheated scalpel. The width of the indurated edges of the wounds cut by the heated scalpel was significantly wider than that of the wounds cut by the unheated scalpel (Figure 1). Moreover, the incidence of infection in the wounds caused by the heated scalpel wss 87.5 percent compared with no evidence of infection in wounds cut by the unheated scalpel (p = 0.05) (Figure 2). The inci-
819
Keenan et al
6
p=o.o05
5 4 3
200
2
000 800
I 0
600 HOT SCALPEL
CONTROL SCALPEL
Ftgwe 3. The member of bacteria in wounds cut by the heat& s&d bras StpdfkMtty mater than th8t in IM?M& msk by ttk? unheatedsclpel.
dence of infection correlated with the level of bacterial contamination. The number of bacteria in wounds cut by the heated scalpel was significantly greater than that in wounds cut by the unheated scalpel (p = 0.01) (Figure 3). This damage to the wounds’ resistance to infection due to the heated scalpel was also associated with evidence of impaired healing. Fifteen days after wounding, the tensile strength of wounds cut by the heated scalpel was significantly lower than that noted in wounds cut by the unheated scalpel (p = 0.005) (Figure 4). Comments An ancient aphorism concerning the power of cautery proclaimed that “those diseases which medicine does not cure, iron cures; those which iron cannot cure, fire cures; those which fire cannot cure, are to be reckoned incurable” [z]. From surgery’s beginning and well into the 19th century, cautery heated over a bed of hot coals was regularly prepared to control hemorrhage as well as to serve as an antiputrefactive agent. Modern surgeons can now cut tissue with a new heated scalpel whose temperature can be controlled within narrow limits. Levenson and colleagues (11 reported that the heated scalpel allowed excision of third degree burns in pigs and human subjects with much smaller blood loss compared with the usual cold scalpel. Skin grafts applied immediately after excision had excellent rates of success similar to those of grafts applied immediately after excision with the unheated scalpel. These investigators also reported that the heated knife did not interfere with the
820
400 200 0
HOT
CONTROL
SCALPEL
SCALPEL
wounds’ ability to resist infection. In wounds in experimental animals made by either a heated or unheated scalpel and then contaminated with 100 million Pseudomonas aeruginosa or Staph. aureus, no wound infection developed in either group. The absence of infection in wounds made either by the heated or unheated scalpel is difficult to explain since the inoculum used was 100 times greater than the infective dose for these pathogens in soft tissues. Consequently, inoculation of 100 million organisms should have resulted in gross evidence of infection in all wounds. Moreover, Levenson and colleagues reported that the heated scalpel produced limited adverse effects on wound repair. Using a temperature of 180% the breaking strengths of wounds made by the hot scalpel did not differ significantly from those in wounds made by the cold scalpel 3,14,25,28, and 42 days after wounding. The only statistically significant difference (p cO.05) between the breaking strengths of incisions made by the unheated scalpel and the heated scalpel was noted at 21 days and was modestly in favor of the conventional scalpel. The innocuaus effects of the heated scalpel could not be confirmed by our study. Using scalpels heated to a considerably lower temperature than that employed in the study of Levenson et al, we found that the heated knife damaged the wounds’ resistance to infection and interfered with healing. These findings are consistent with our earlier investigations in which
The American Journal
efSurgery
surgw cautery Revisited we reported that electrosurgery and the laser produced deleterious effects on tissue resistance to infection and wound healing [3]. It is our belief that wounds made by the stainless steel scalpel exhibit a greater resistance to infection and enhanced tensile strength compared with wounds made by any hemostatic scalpel. However, the benefits of the surgical scalpel must be weighed against the attendant blood loss in some clinical cases that may pose a threat to a patient’s life. In massive excisional surgery, such as large soft tissue tumors and debridement of third degree burns, a hemostatic scalpel should be employed since the consequences of blood loss outweigh the potential problems of infection and impaired healing. Although it is unlikely that a hemostatic scalpel will be developed that produces no adverse effects, this realization should not limit the search for a hemostatic scalpel that can limit blood loss with the least possible damage to tissue. For cases in which attendant blood loss after the surgical incision is not a significant threat to the patient’s life, the unheated scalpel is still the knife of choice, and bleeding should be controlled by pressure, with pinpoint electrocoagulation being reserved for bleeding vessels.
vow?m147, Juns 1)04
Summary A new hemostatic scalpel has been developed to control bleeding between the cut edges of wound tissue. The scalpel blade resembles conventional scalpel blades, except that it can be heated and its temperature controlled within narrWvlimits. cutting is accomplished by the blade’s sharp edges, and hemost&s results from the direct transfer of heat from the blade to the tissue. This experimental study has demonstrated .that the hemostatic effect of the scalpel is associated with damage to the tissue’s defenses against infection and impaired wound healing.
Levenson SM, Gruber DK, Gruber C, Seifter E, Molw J, Pefro J. A hemoetetic scalpel for burn debrldement. Arch Svg 1982;117:213-20. WangeMeen OH, Wangensteen SD. The rise of surgery from empiric aaft to !&at?tific disciptine. Mhmeppolis: Unlverslty of Minnesota Press, 1978:21. MaddenJE,EdiichRF,CueterJFl,PaiwkPH,ThuiJ,Wangensteen CM. Studies in the management of the conbmbated wound. IV. Resistance to infection of eurgical wounds made by the knife, electrosurgety, and laser. Am J Surg 1970;119: 222-4.
821
Kevin M. Keenan, MD, Charlottesville, Virginia George 1. Rodeheaver, PhD, Charlottesville, Virginia John G. Kenney, MD, Charlottesville, Virginia Richard F. Edlkh, MD, PAD, Charlottesville, Virginia
The ideal surgical knife incises tissues without bleeding and does not interfere with wound repair or resistance to infection. The control of bleeding that occurs when living tissues are cut is a very important consideration in massive excisional operations, such as soft tissue tumors and debridement of third degree burns. The attendant blood loss often poses a major problem and may be a serious threat to the patient’s life. If these operative procedures could be conducted with markedly lessened blood loss and without significant local adverse effects, it would shorten the length of the operative procedure and eliminate the need for blood transfusions. A new hemostatic scalpel has been invented by Shaw to control the bleeding between the cut edges of the tissue [I]. This scalpel blade resembles conventional scalpel blades, except that it can be heated and its temperature controlled within narrow limits. Cutting is accomplished by the blade’s sharp edges and hemostasis results from the direct transfer of heat from the blade to the adjacent tissue during its passage through the tissue. The purpose of our study was to assess the effect of this scalpel on the healing of the wound and its resistance to infection. Material and Methods The new hemostatic scalpel used in this study is similar
in size and shape to a no. 15 blade. The scalpel handle is connected to a controller unit that provides a pulsed direct current to heat the scalpel to an elevated temperature ranging from 110 to 2WC. The controller senses and powers the microelectronic circuitry in the scalpel blade to maintain the desired temperature. Since the patient is From the Universityof Virginlal3umCenter and Departmentof PlasticSurgery, UniversityOf Virginia Schoolof Medicine,Charlottesville,Virginia. Requests for reprints shouldbe addressedto Richard F. Edlich, MD. Universityof Virginiaschool of Medicine,Box 332, Char!&tesvlile,Vlrginla 22909.
018
insulated from the electronic parts of the scalpel, a patient grounding pad is not needed. Blade temperatures of 160 to 160°C are often used clinically to limit bleeding during excisions or.incisions. A temperature of 114% is sufficient to control bleeding to some degree. Since the cutting edge of the hemostatic scalpel is similar to that of a conventional scalpel, cutting can be accomplished without the use of heat. Since hemostasis results from the direct transfer of heat from the edge of the scalpel, an unheated control scalpel has no hemostatic effect. Experimental design: The experimental model utilized in this study is reliable and reproducible in day-to-day assessment, and is also susceptible to replication in other laboratories. The albino guinea pig was chosen because of its availability and its susceptibility to infection caused by the pyogenic bacteria most commonly responsible for wound infection in human subjects. Hartley guinea pigs that weighed 300 to 350 g were caged individually and given food and water ad libitum during the period of study. The animals were anesthetized with pentobarbital admiitered intraperitoneally. On the day of the operation, the hair on the back of each animal was clipped with electric clippers. The remaining hair was then removed with a depilatory, and the operative site was washed with an iodophor solution and isolated with sterile drapes. Under aseptic conditions, two different techniques were employed to make separate incisions, 3 cm in length, parallel and equidistant from the vertebral spine, that extended through the panniculus carnosus down to the fascia. One incision was made by a scalpel heated to 120°C, and the other incision was made by a control scalpel of the same type that was unheated. A new scalpel blade was used to make each incision. The force applied to the scalpels was sufficient to cut through the skin with one stroke. The rate at which the heated scalpel cut through the skin was sufficient to limit the relative magnitude of blood loss from the wound as compared with the rate of blood loss due to the unheated scalpel. In the wound made by the unheated scalpel, pressure was applied to the wound site with gauze sponges to secure hemc&asis. Sites in which the heated and unheated scalpels were employed were
The American Joumal d Surgery
Surgical
cautefy Revlslted
3.25 f2.18
HOT SCALPEL
CONTROL SCALPEL
randomly assigned for each animal The animalswere then randomly divided into two different groups. In one treatment group, an inoculum of 100,000 Staphylococcusaureus was introduced into each wound. This level of bacterial contamination does not result in infection unless the resistance of the wound to infection is impaired.Five minutes after bacterial contamination, the wound edges were approximated by microporous tape. In the other group of animals without bacterial contamination, closure was accomplished by tape 10 minutes after wounding. In the animals with wounds subjected to bacterial contamination, the inflammatoryresponsesand concentration of bacteria were recorded 4 days after wounding. Tbe infknm&ry responsesasses& were wound induration and the presence of purulent exudate. Induration of the wound was determined by palpating its middle with the gloved finger on the fourth postoperative day. Tbe indurated margin at the middle of the wound was measured in millimeters. After each measurement,tbe wound was opened and inspected for evidence of a purulent exudate. In each wound, an estimate of tbe number of viable bacteriaon the wound surfacewas made. After swabbingthe length of the wound with a sterile cotton-tipped applicator, it was immersed in a glasstube containing 5 ml of 0.85 percent saline solution. The tube was then placed on a Vortexe mixer for 1 minute. The number of bacteria suspended in the saline solution was quantitated by standard microbiologic serial dilution and plating techniqu8s. The results were reported as the average logarithm of the bacterial count since it more accurately reflected the logarithmic growth of the organism. Ah r8suhs w8r8 subjected to statistical analysis utilizing a 95 percent confidence coefficient as a criterion of significance. Quantitative estimates of the number of bacteria and the induration measurements were analyzed using the Student’s t test for paired differences. Significance of the gross infection score was d8termined by the Wilcoxon two-sample rank sum test. In the animals with wounds that were not subjected to bacterial contamination,
voknw 147, Jlmn 1984
HOT SCALPEL
CONTROL SCALPEL
the wound tensile strength was recorded 15 days after wounding. The paravertebral wounds were excised with a generous margin of surrounding skin. Strips of skin of identical width (0.8 cm) and length (3.5 cm) were excised transversely across the middle of the wound. The breaking strength of the wound was then determined by attaching the ends of the wound to a continuous drive motor with a screw-gear advance. The drive motor was attached to a strain gauge that was electrically connected to a HewlettPackard’s recorder through an amplifier system. As the drive motor pulled the clip at a rate of 8.8 cm/min, the strain gauge recorder system provided a measure of the applied force necessary to disrupt the wound. Tensile strength was calculated for each wound by dividing the breaking strength value by the thickness of the test strip. The skin thickness was determined by a dial micrometer after the excised skin had been stretched back to its original size before excision. The significance ofthe tensile strength measurements for each wound was determined using the Student’s t test for paired differences.
Results The heated scalpel damaged the wounds’ resistance to infection when compared with the unheated scalpel. After bacterial contamination with a subinfective dose of inoculum, the inflammatory response of wounds made by the hot scaIpo1 was significantly greater than that made by the unheated scalpel. The width of the indurated edges of the wounds cut by the heated scalpel was significantly wider than that of the wounds cut by the unheated scalpel (Figure 1). Moreover, the incidence of infection in the wounds caused by the heated scalpel wss 87.5 percent compared with no evidence of infection in wounds cut by the unheated scalpel (p = 0.05) (Figure 2). The inci-
819
Keenan et al
6
p=o.o05
5 4 3
200
2
000 800
I 0
600 HOT SCALPEL
CONTROL SCALPEL
Ftgwe 3. The member of bacteria in wounds cut by the heat& s&d bras StpdfkMtty mater than th8t in IM?M& msk by ttk? unheatedsclpel.
dence of infection correlated with the level of bacterial contamination. The number of bacteria in wounds cut by the heated scalpel was significantly greater than that in wounds cut by the unheated scalpel (p = 0.01) (Figure 3). This damage to the wounds’ resistance to infection due to the heated scalpel was also associated with evidence of impaired healing. Fifteen days after wounding, the tensile strength of wounds cut by the heated scalpel was significantly lower than that noted in wounds cut by the unheated scalpel (p = 0.005) (Figure 4). Comments An ancient aphorism concerning the power of cautery proclaimed that “those diseases which medicine does not cure, iron cures; those which iron cannot cure, fire cures; those which fire cannot cure, are to be reckoned incurable” [z]. From surgery’s beginning and well into the 19th century, cautery heated over a bed of hot coals was regularly prepared to control hemorrhage as well as to serve as an antiputrefactive agent. Modern surgeons can now cut tissue with a new heated scalpel whose temperature can be controlled within narrow limits. Levenson and colleagues (11 reported that the heated scalpel allowed excision of third degree burns in pigs and human subjects with much smaller blood loss compared with the usual cold scalpel. Skin grafts applied immediately after excision had excellent rates of success similar to those of grafts applied immediately after excision with the unheated scalpel. These investigators also reported that the heated knife did not interfere with the
820
400 200 0
HOT
CONTROL
SCALPEL
SCALPEL
wounds’ ability to resist infection. In wounds in experimental animals made by either a heated or unheated scalpel and then contaminated with 100 million Pseudomonas aeruginosa or Staph. aureus, no wound infection developed in either group. The absence of infection in wounds made either by the heated or unheated scalpel is difficult to explain since the inoculum used was 100 times greater than the infective dose for these pathogens in soft tissues. Consequently, inoculation of 100 million organisms should have resulted in gross evidence of infection in all wounds. Moreover, Levenson and colleagues reported that the heated scalpel produced limited adverse effects on wound repair. Using a temperature of 180% the breaking strengths of wounds made by the hot scalpel did not differ significantly from those in wounds made by the cold scalpel 3,14,25,28, and 42 days after wounding. The only statistically significant difference (p cO.05) between the breaking strengths of incisions made by the unheated scalpel and the heated scalpel was noted at 21 days and was modestly in favor of the conventional scalpel. The innocuaus effects of the heated scalpel could not be confirmed by our study. Using scalpels heated to a considerably lower temperature than that employed in the study of Levenson et al, we found that the heated knife damaged the wounds’ resistance to infection and interfered with healing. These findings are consistent with our earlier investigations in which
The American Journal
efSurgery
surgw cautery Revisited we reported that electrosurgery and the laser produced deleterious effects on tissue resistance to infection and wound healing [3]. It is our belief that wounds made by the stainless steel scalpel exhibit a greater resistance to infection and enhanced tensile strength compared with wounds made by any hemostatic scalpel. However, the benefits of the surgical scalpel must be weighed against the attendant blood loss in some clinical cases that may pose a threat to a patient’s life. In massive excisional surgery, such as large soft tissue tumors and debridement of third degree burns, a hemostatic scalpel should be employed since the consequences of blood loss outweigh the potential problems of infection and impaired healing. Although it is unlikely that a hemostatic scalpel will be developed that produces no adverse effects, this realization should not limit the search for a hemostatic scalpel that can limit blood loss with the least possible damage to tissue. For cases in which attendant blood loss after the surgical incision is not a significant threat to the patient’s life, the unheated scalpel is still the knife of choice, and bleeding should be controlled by pressure, with pinpoint electrocoagulation being reserved for bleeding vessels.
vow?m147, Juns 1)04
Summary A new hemostatic scalpel has been developed to control bleeding between the cut edges of wound tissue. The scalpel blade resembles conventional scalpel blades, except that it can be heated and its temperature controlled within narrWvlimits. cutting is accomplished by the blade’s sharp edges, and hemost&s results from the direct transfer of heat from the blade to the tissue. This experimental study has demonstrated .that the hemostatic effect of the scalpel is associated with damage to the tissue’s defenses against infection and impaired wound healing.
Levenson SM, Gruber DK, Gruber C, Seifter E, Molw J, Pefro J. A hemoetetic scalpel for burn debrldement. Arch Svg 1982;117:213-20. WangeMeen OH, Wangensteen SD. The rise of surgery from empiric aaft to !&at?tific disciptine. Mhmeppolis: Unlverslty of Minnesota Press, 1978:21. MaddenJE,EdiichRF,CueterJFl,PaiwkPH,ThuiJ,Wangensteen CM. Studies in the management of the conbmbated wound. IV. Resistance to infection of eurgical wounds made by the knife, electrosurgety, and laser. Am J Surg 1970;119: 222-4.
821