The loop and knot securities of two polyfilament and two monofilament sutures of four diameters (3.0, 2.0, 0, 1) were evaluated with a tensiometer for four four-throw knots, known to be secure with a 2.0 polyfilament suture. Loop security of Monocryl 1 is low, being 14.7 ± 3.0 Newton (N) for a three-throw half-knot (H3) and 15.4 ± 2.4 N and 28.3 ± 10 N for two (SSs) and four (SSsSsSs) symmetrical sliding half-hitches. This is lower than 18, 24, and 46 N for similar knots with Vicryl. Polyfilament sutures have excellent knot security for all four diameters. Occasionally, some slide open with slightly lower knot security, especially for larger diameters, although this is not clinically problematic. Knot security of monofilament sutures was unpredictable for all four knots, especially for larger diameters, resulting in many clinically insecure knots. A secure monofilament knot requires a six-throw knot with two symmetrical sliding half-hitches or two symmetrical half-knots secured with four asymmetric blocking half-hitches. In conclusion, with polyfilament sutures, four- or five-throw half-knot or half-hitch sequences result in secure knots. For monofilament sutures, loop and knot security is much less, half-knot combinations should be avoided, and secure knots require six-throw knots with four asymmetric blocking half-hitches.

Surgical knots are sequences of half-knots (H) or half-hitches (S), defined by their number of throws, by an opposite or similar rotation compared with the previous one, and for half-hitches whether they are sliding (s) or blocking (b). Opposite rotation results in (more secure) symmetric (s) knots, similar rotation in asymmetric (a) knots, and changing the active and passive ends has the same effect as changing the rotation. Loop security is the force to keep tissue together after a first half-knot or sliding half-hitches. With polyfilament sutures, H2, H3, SSs, and SSsSsSs have a loop security of 10, 18, 28, and 48 Newton (N), respectively. With monofilament sutures, they are only 7, 16, 18, and 25 N. Since many knots can reorganize, the definition of knot security as the force at which the knot opens or the suture breaks should be replaced by the clinically more relevant percentage of clinically dangerous and insecure knots. Secure knots with polyfilament sutures require a minimum of four or five throws, but the risk of destabilization is high. With monofilament sutures, only two symmetric+4 asymmetric blocking half-hitches are secure. In conclusion, in gynecology and in open and laparoscopic surgery, half-hitch sequences are recommended because they are mandatory for monofilament sutures, adding flexibility for loop security with less risk of destabilization.

The loop and knot securities of 2 braided and 2 monofilament sutures of four diameters (3.0, 2.0, 0, 1) were evaluated with a tensiometer for four 4-throw knots known to be secure with a 2.0 polyfilament suture. Loop security of monocryl 1 is low, being 14.7 + 3.0 Newton (N) for a 3-throw half-knot (H3) and 15.4 + 2.4 N and 28.3+ 10 N for 2 (SSs) and 4-throw (SSsSsSs) symmetrical sliding half-hitches. This is lower than 18, 24, and 46 N for similar knots with vicryl. Polyfilament sutures have excellent knot security for all diameters. Occasionally, some slide to open with slightly lower knot security, especially for larger diameters, although not clinically problematic. Knot se-curity of monofilament sutures was unpredictable for all 4 knots, especially for larger diameters, resulting in many clinically insecure knots. A secure monofilament knot requires a 6-throw knot with 2 symmetrical sliding half-hitches or 2 symmetrical half-knots secured with 4 asymmetric blocking half-hitches. In conclusion, with polyfilament sutures, 4 or 5-throw half-knot or half-hitch sequences result in secure knots. For monofilament sutures, loop and knot security is much less, half-knot combinations should be avoided, and secure knots require 6-throw knots with 4 asym-metric half hitches. This conclusion is valid for gynecologic laparoscopic and open surgery, and for surgery in general.

Surgical knots are sequences of half-knots (H) or half-hitches (S), defined by their number of throws, by an opposite or similar rotation compared with the previous one and for half-hitches, whether sliding (s) or blocking (b). Opposite rotation results in (more secure) symmetric (s) knots, similar rotation in asymmetric (a) knots, and changing active and passive ends has the same effect as changing rotation. Loop security is the force to keep tissue together after a first half-knot or sliding half-hitches. With polyfilament sutures H2, H3, SSs and SSsSsSs have a loop security of 10, 18, 28 and 48 Newton (N), respectively. With monofilament sutures, they are only 7, 16, 18 and 25N. Since many knots can reorganise, the definition of knot security as the force at which the knot opens or the suture breaks should be replaced by the clinically more relevant percentage of clinically dangerous and insecure knots. Secure knots with polyfilament sutures require a minimum of 4 or 5 throws, but the risk of destabilisation is high. With monofilament sutures, only 2 symmetric+4 asymmetric blocking half-hitches are secure. In conclusion, half-hitch sequences are recommended since mandatory for monofilament sutures, adding flexibility for loop security with less risk of destabilisation.

The relationship between tissue effects, intensity (I), and voltage (V) of a high-frequency alternative current seems well known. However, the translation of the settings of the electrosurgical unit and their use during surgery seems not to be unanimously understood by all surgeons. This results in many variations of surgical technique and plenty of specific questions asked during live surgery. Above 200 V, the heat of the sparks results in the explosion of superficial cells and a cutting effect. With higher voltages, the associated coagulation is increasing. Voltage and amount of energy (Watt=I*V) are independent since a similar amount of energy can be obtained with a continuous current or an intermittent current half the time and a double voltage. Below 200 V, tissue is heated until the steam from boiling tissue stops the current. Therefore, slower heating with less energy or a larger contact area permits deeper coagulation. The maximal output (W) of the electrosurgical unit results in versatility of use besides being a safety measure. The current intensity increases with the area of contact. Therefore, when I*V exceeds the preset output, V has to drop. A limited maximal output thus permits using the same instrument for non-contact cutting with >200V and sparks and coagulation when the contact area is much larger. In conclusion, the tissue effects of electrosurgery vary with the device’s voltage setting (often indicated as force) and the maximal output. The sur-geon’s choice to cut or coagulate by changing the contact area adds versatility.