Canine laparoscopic ovariectomy using two 3- and 5-mm portal sites: A prospective randomized clinical trial

Abstract

Laparoscopic ovariectomy (LapOve) was performed in 3 groups (2.7-mm/5-mm, 5-mm/3-mm, and 5-mm telescope/5-mm bipolar forceps) of small dogs (n = 60). Surgical times, bleeding rates, complications, and laparoscopic visualization were recorded and compared among groups. Use of the 3-mm bipolar forceps significantly increased the surgical time and showed higher bleeding rates compared with the 5-mm bipolar forceps. The 2.7-mm telescope significantly decreased the laparoscopic view. No complications were seen in any group. In conclusion, the 2.7-mm 30° telescope or the 3-mm bipolar forceps combined with the 5-mm instruments could be used as an alternative technique for LapOve in dogs up to 10 kg. The 2.7-mm telescope with the 5-mm bipolar forceps was the most efficient combination based on surgical time.

Introduction

Laparoscopic ovariectomy (LapOve) is widely used for the spaying of dogs. The technique is constantly changing in order to reduce the number of portal sites and the diameter of instruments used with the goal of improving patient recovery. Laparoscopic ovariohysterectomy and ovariectomy procedures in dogs are associated with less postoperative pain and a faster return to normal activity versus open spaying procedures (1). In small dogs, LapOve results in increased postoperative activity counts compared with using an open technique (2). The use of two 5-mm and 10-mm portals is well-accepted for LapOve in dogs (3–6), although technical improvement in laparoscopes and instruments can reduce invasiveness by using 3.5-mm and 2.5-mm ports (7). Studies in human patients have found that smaller surgical wounds as a result of using smaller instruments cause less postoperative pain and lower morbidity rates compared with standard laparoscopic procedures, enhancing cosmetic results with similar levels of surgical safety (8–10). In exotic species, the 2.7-mm telescope and 3-mm instrumentation are preferred for laparoscopic abdominal procedures in animals weighing less than 10 kg (e.g., many primates, felids, rabbits, and rodents) (11). In dogs and cats, small diameter endoscopes (< 5 mm) are used for explorative procedures in small cavities (12), and use of the 5-mm to 10-mm devices for ovarian pedicle hemostasis has been extensively reported (6,13–15). In contrast, there are no reports on the use of either a 2.7-mm telescope or 3-mm bipolar forceps for the LapOve in dogs.

In this study, 1 of the two 5-mm portals in the LapOve technique in small dogs was replaced with a 3-mm portal and 2 combinations of instruments were analyzed: a 2.7-mm telescope together with a 5-mm bipolar forceps and a 5-mm telescope together with a 3-mm bipolar forceps. We compared these combinations with a technique using two 5-mm portal sites as a control group. The goal was to test the effectiveness of each laparoscopic instrument for LapOve and to establish the most efficient combination based on surgical times, bleeding rates, surgical and postoperative complications, and laparoscopic field of view.

Materials and methods

All procedures were performed in accordance with the Spanish Government for Animal Care guidelines (RD 53/2013).

Client-owned sexually intact female dogs (n = 60) brought to a private veterinary center for routine spaying between February 2013 and January 2016 were enrolled in the study if they were healthy and weighed up to 10 kg. Owners signed a client consent document advising them of the risks of LapOve and the possible need to convert to an open celiotomy under emergency situations such as hemorrhage or iatrogenic damage. All dogs underwent at minimum a complete blood (cell) count (CBC) and coagulation test, and their medical history was recorded. Dogs were randomly distributed into 3 groups (n = 20 dogs per group) by a random number generator, and those with abnormal findings of either the uterus or ovaries (e.g., ovarian cyst, ostensible uterine disease) observed during laparoscopy were excluded. Surgeries were performed by 2 veterinary surgeons, both right hand dominant, with similar experience in minimally invasive techniques (> 80 laparoscopic proceedings each, including reproductive, digestive and urinary laparoscopic surgeries).

The anesthesia protocol used was the same for all animals and dogs were classified as ASA class I (American Society of Anesthesiologists). They were premedicated with medetomidine (Domtor; Norvet, Barcelona, Spain), 5 μg/kg body weight (BW), IM and methadone (Metasedin; Esteve, Barcelona, Spain), 0.2 mg/kg BW, IM. Amoxicillin (Noroclav; Norbrook, Newry, Ireland), 8.75 mg/kg BW, SC was administered 30 min before surgery. One cephalic vein was catheterized and meloxicam (Metacam; Boehringer Ingelheim, Barcelona, Spain), 0.2 mg/kg BW, IV, was administered. Ringer’s lactate solution (Lactato-RingerVet; B. Braun, Barcelona, Spain) 5 mL/kg BW per hour, was infused during anesthesia. Once sedated, dogs were clipped from the xiphoid process to the pubis, transferred to the surgical theater, disinfected, and draped for surgery. Anesthesia was induced with propofol (Propofol Lipuro; B. Braun), 1 to 2 mg/kg BW, IV, to effect and maintained with isoflurane in oxygen after intubation. Volume-controlled automatic intermittent positive pressure ventilation was started under a circle breathing system. A respiratory rate of 12 breaths/min was preset, and airway pressure remained below 18 cm H₂O. Monitoring included heart rate, respiratory rate, electrocardiography, non-invasive blood pressure, and ETCO₂.

Surgical procedures

One surgeon held both the telescope and the instruments. The second surgeon performed auxiliary tasks such as providing instruments to the main surgeon. Surgeries were alternated between the 2 surgeons.

5-mm bipolar forceps group (5BF Group)

Surgeries were performed using a threaded 5-mm cannula (6-cm length trocar, Karl Storz, Tuttlingen, Germany) and a threaded 3.5-mm cannula (5-cm length trocar; Karl Storz). Treatment in this group was performed with a 2.7-mm 30° telescope (Hopkins II; Karl Storz), 5-mm bipolar forceps (RoBi; Karl Storz), and 5-mm bipolar scissors (RoBi; Karl Storz). Dogs were placed in dorsal recumbency on the operating table without being tied down except in cases in which the hindlimbs occupied part of the working area. Supplemental warming was provided (Vacu Support; Buster, Langeskov, Denmark). The bladder was emptied either by catheterization (in dogs > 3 kg) or by manual compression (in dogs < 3 kg).

The first cannula (5 mm in all cases) was placed 1 cm caudal to the umbilicus. A perimeter mark was made with the sleeve of the trocar to achieve the exact length of the incision and a modified Hasson technique (16) was used. The trocar was introduced with a blunt obturator in all cases. When the first trocar was in place, the abdomen was insufflated with carbon dioxide (CO₂) and a pressure of 11 mmHg was maintained throughout placement of the second cannula. Once the second cannula was in place, the pressure was decreased and maintained at 6 to 9 mmHg with a pressure-regulating mechanical insufflator (Endoflator; Karl Storz). For the second access portal, the 3.5-mm cannula with a blunt obturator was placed 1 to 2 cm cranial to the umbilicus without direct visualization. To achieve an incision to tightly fit the outer diameter of the 3.5-mm cannula, the perimeter of the sleeve was marked and a No. 11 scalpel blade was used, first focusing on the skin, and then making a puncture on the linea alba. The right hand was used to place this cannula. To avoid excessive penetration during its placement, the surgeon’s index finger was put over the sleeve making a stop against the abdominal wall. Once the 2.7-mm telescope was introduced through the 3.5-mm cannula, the abdominal viscera were explored following a standard clockwise procedure to assess possible iatrogenic damage before the identification of the ovary.

The patient was rotated manually by the auxiliary surgeon into left lateral oblique recumbency for identification of the right ovary. In all cases a Maryland dissector (Clickline; Karl Storz) was used to expose the ovary and a 2/0 transabdominal monofilament suture (Monosyn; Braun) with a trocar point 1/2 circle round-bodied needle held the ovary on the abdominal wall. The ovariectomy was completed by first cauterizing with the 5-mm bipolar forceps and then transecting the ovarian pedicle with the 5-mm scissors, followed by the mesovarium, suspensory ligament, and caudal to the proper ligament. Once the right ovary was completely separated from the adjacent tissue, the abdomen was inspected to evaluate for the presence of bleeding. The resected right ovary was then grasped with the Maryland dissector, released from the transabdominal suture, and taken out from the abdomen through the caudal incision once the trocar was removed. The pneumoperitoneum was lost after removing the right ovary from the abdomen. The caudal trocar was replaced into the abdomen provided by its blunt obturator and the pneumoperitoneum was re-established. The animal was rotated to the right side to expose the left ovary. The left ovary was then removed in the same manner as the right ovary. Large ovaries and the associated mesovarium could be removed from the abdominal cavity by first grasping the proper ligament and then removing the fat tissue around them.

Following removal of both ovaries, the muscular layer of the 5-mm portal with the abdominal fascia was closed with a simple interrupted suture pattern with 3-0/4-0 absorbable monofilament suture (Monosyn; Braun). This pattern and suture were also used for the subcutaneous layer, and the skin was closed using an intradermal pattern with a single absorbable 4-0 suture (Monosyn; Braun) followed by the application of tissue adhesive (Vetbond; 3M, St. Paul, Minnesota, USA). The tissue adhesive was carefully applied to avoid formation of a dry adhesive plate around the incision. For the 3.5-mm portal (cranial site), only tissue adhesive was used for skin closure without muscle or subcutaneous sutures.

3-mm bipolar forceps group (3BF Group)

The same cannulas were used in this group as in the previous group. Treatment was performed with a 5-mm 0° telescope (Hopkins II; Karl Storz), 3-mm bipolar forceps (Take Apart; Karl Storz), and 3-mm scissors (Clickline; Karl Storz). The technique in this group had several differences from that in the previous group. Once the 6-mm cannula was placed in the caudal site, the 5-mm telescope was introduced to the abdominal cavity and the 3.5-mm cannula was placed under direct visualization. Ovaries were resected as described for the 5BF group but using the 3-mm bipolar forceps and the 3-mm scissors. To remove ovaries from the abdomen, a 3-mm dissector (Clickline; Karl Storz) in the cranial position was used as follows: once the resected ovary was grasped and the transabdominal suture released, the 6-mm cannula (caudal cannula) was taken out, and the tip of the 3-mm dissector with the resected ovary was easily palpated below the skin, then directed to the caudal wound and exteriorized to take out the ovary. The 5-mm port site was closed in the same manner as described for the 5BF group.

5-mm bipolar forceps and 5-mm telescope (control group)

Surgeries were performed using two threaded 5-mm cannulas (6-cm length trocar; Karl Storz). The procedure was the same as described in the 5BF Group but with the difference that the cranial cannula was placed under direct visualization and the 2 portal sites were sutured for closure.

Measured variables

Data recorded included breed, body weight, age, and fat score of the ovarian pedicle (FSOP; 0 = no fat; 1 = small amount of fat; 2 = moderate amount of fat; and 3 = large amount of fat) (15). Surgical stages were timed with a stop watch. The following stages were recorded: insertion of both cannulas (Stage I); resection of the right ovary (Stage II); removal of the right ovary (Stage III); resection of the left ovary (Stage IV); removal of the left ovary (Stage V); closure (Stage VI) and total surgical time (first skin incision to last skin or portal suture). Unidentified images from 10 procedures belonging to the 5BF and 3BF groups were classified by surgeons, added to an online questionnaire and sent to 15 blinded observers experienced in laparoscopic surgery. The laparoscopic view was then subjectively rated as adequate or inadequate. If the laparoscopic view was assessed as inadequate, the observer was asked about his/her reasons (lack of light, lack of sharpness or definition, lack of visual field, and other). Images showed the same structures (ovary with ovarian pedicle), and similar settings of the camera were used. Pictures were selected by surgeons (Granados, Martínez) and the main goal of selection was to get the best quality images from recorded videos of 20 dogs (10 dogs each for the 2.7- and 5-mm telescopes). Occurrence of intra-operative bleeding and other problems related to surgery were recorded. Wound lengths of the cranial (3.5 mm) and caudal (5 mm) portal sites belonging to the 5BF and 3BF groups were measured, and healing complications observed as dehiscence or seroma formation among all groups were recorded.

All dogs were sent home the same day of surgery. A physical check was performed 24 h after surgery, at which time meloxicam (Metacam; Boehringer Ingelheim), 0.2 mg/kg BW, SC, was administered subcutaneously for analgesia. A physical examination was repeated 10 d after surgery, and the presence of proper wound healing was evaluated.

Data were summarized as mean ± standard deviation (SD) or as median and range. The normal distribution of quantitative variables was checked by the Kolmogorov-Smirnov test. An unpaired t-test (parametric) or U-Mann Whitney test (non-parametric) was used to compare 2 means. The analysis of variance (ANOVA) or Kruskal-Wallis tests were used to compare more than 2 means. Categorical data were analyzed with a Chi-squared (χ²) test. All analyses were performed with standard software (SPSS, Chicago, Illinois, USA). Values of P < 0.05 were considered significant.

Results

Sixty dogs were enrolled in the study. Animals of 15 breeds were included with mixed-breed dogs being most represented (n = 16), followed by dachshunds (n = 11), Yorkshire terriers (n = 10), Maltese (n = 5), miniature schnauzers (n = 4), Chihuahuas (n = 3), beagles (n = 2), pugs (n = 2), and bodeguero Andaluz, Chinese crested, Pomeranian, fox terrier, coton de Tulear, French bulldog, and shih tzu (n = 1 each). For all dogs, mean ± SD body weight was 5.4 ± 2.3 kg (range: 1.3 to 10 kg). Mean body weight was 5.1 ± 2.4 kg (range: 1.5 to 10 kg) in the 5BF group, 4.5 ± 2.2 kg (range: 1.3 to 9.4 kg) in the 3BF group, and 6.7 ± 1.8 kg (range: 2.3 to 9.6 kg) in the control group. Body weight differed significantly between the 3BF group and control group (P = 0.005). The mean age of all dogs was 40.1 ± 40.7 mo (range: 5.0 to 171.6 mo). The mean age in each group was 32.2 ± 30.5 mo for the 5BF group (range: 7.2 to 144.0 mo), 30.7 ± 35.3 mo for the 3BF group (range: 5.0 to 101.3 mo), and 57.62 ± 49.8 mo for the control group (range: 9.6 to 171.6 mo). There were no significant differences in age between groups (P = 0.061). The mean FSOP of all dogs was a moderate amount of fat (1.9 ± 0.8) and was similar among groups with no significant differences (P = 0.587). The mean FSOP was 2.0 ± 0.8 (moderate) in the 5BF group (range 1 to 3), 1.85 ± 0.8 (moderate) in the 3BF group (range 1 to 3) and 2.1 ± 0.7 (moderate) in the control group (range: 1 to 3). No significant differences were seen among groups (P = 0.642).

Across the 3 groups, surgical time was 40.5 ± 9.2 min (range: 25 to 66 min). The mean total surgical time was 37.9 ± 7.8 min in the 5BF group (range: 26 to 54 min), 45.2 ± 9.5 min in the 3BF group (range: 30 to 66 min), and 38.7 ± 8.8 min in the control group (range: 25 to 53 min). There was a significant difference between groups 5BF and 3BF (P = 0.020) (Figure 1). The time needed for right ovary resection (Stage II) was significantly longer in the 3BF group compared with the control group (8.1 ± 3.2 min versus 5.3 ± 2.9 min, P = 0.017) and left ovary resection (Stage IV) was significantly longer in the 3BF group than in the 5BF and control groups (9.9 ± 4.9 min versus 6.6 ± 3.9 and 5.3 ± 2.3 min, respectively, P = 0.020). There were no significant differences in time for removal of both ovaries (Stages III and V; P = 0.421 and P = 0.430, respectively). Stage VI was significantly longer in the control group compared with the 5BF group (9.0 ± 3.1 min versus 5.7 ± 2.3 min, P = 0.001) (Table 1). Compared to dogs with high FSOP, dogs with low FSOP showed significant differences in resection time of both ovaries when the 3-mm bipolar forceps was used (3BF group) (Stage II, P = 0.004; Stage IV, P = 0.010) as well as in total surgical time (P = 0.032). In dogs belonging to the 5BF group, significant differences in total surgical time were seen between those with low FSOP and high FSOP (P = 0.028). In the control group, compared to dogs with moderate FSOP, dogs with low FSOP showed a significant difference in total surgical time (P = 0.020). Also in the control group, significant differences were seen between dogs with low and high FSOP in Stage I (P = 0.012), Stage II (P = 0.042), and total surgical time (P = 0.000). Regardless of the instruments used, total surgical time was increased by 14% between low and moderate; 25% between low and high; and 13% between moderate and high FSOP. Also, there was significant difference in total surgical time between low and high FSOP (P = 0.000).

Figure 1.

Total surgical time. The time was significantly longer in the 3BF group compared with the 5BF and control groups (P = 0.020).

Table 1.

Duration of surgery (minutes) at surgical stages I to VI

	5BF group	3BF group	Control group
Stage I	5.1 ± 2.1	5.3 ± 2.2	4.6 ± 2.5	P = 0.681
Stage II	7.2 ± 3.7	8.1 ± 3.2	5.2 ± 2.4a	P = 0.017
Stage III	2.6 ± 2.8	3.6 ± 2.6	3.2 ± 1.9	P = 0.421
Stage IV	6.6 ± 3.9	9.9 ± 4.9b	5.3 ± 2.9a	P = 0.020
Stage V	2.0 ± 1.9	2.8 ± 1.9	2.6 ± 1.7	P = 0.430
Stage VI	5.7 ± 2.3	6.3 ± 2.4	9.0 ± 3.1b	P = 0.001

Stage I — skin incision to insertion of both cannulas; Stage II — resection of the right ovary; Stage III — removal of the right ovary; Stage IV — resection of the left ovary; Stage V — removal of the left ovary; Stage VI — closure. Values are mean ± standard deviation.

^aSignificantly different from the 3BF group.

^bSignificantly different from the 5BF group.

Ovarian pedicle bleeding, controlled in all cases with the bipolar forceps, was seen in 25% of the dogs in the 5BF group, 50% in the 3BF group, and 20% in the control group. No significant differences in bleeding rates were found among groups (P = 0.092). No iatrogenic damage related to the placement of the cannulas was observed in any group.

The type of telescope used resulted in a significant difference in laparoscopic view (P = 0.010). The view was classified as adequate in 50% of cases when the 2.7-mm telescope was used and in 100% when the 5-mm telescope was used (Figure 2).

Figure 2.

Examples of photographs submitted along with the questionnaire sent to the blinded observers.

A — Laparoscopic viewing assessed as inadequate (Group 5BF, 2.7-mm telescope); B — Laparoscopic viewing assessed as adequate (Group 5BF, 2.7-mm telescope); C — Laparoscopic viewing assessed as adequate (Group 3BF, 5-mm telescope).

Mean wound length was 4.8 ± 1.4 mm in cranial wounds (3.5-mm cannulas, range: 2 to 7 mm) and 7.1 ± 1.4 mm in caudal wounds (5-mm cannulas, range: 5 to 10 mm). The mean length of the incision of the 3.5-mm portals was 72.5% with respect to the 5-mm portals. A significant difference in length was seen between portal sites (P = 0.000). Cranial wounds in the 3BF group were slightly longer than in the 5BF group but without a significant difference (4.5 ± 1.7 and 5.0 ± 1.1 mm, respectively, P = 0.052). No significant differences were seen in the caudal wounds between the 3BF and 5BF groups (7.05 ± 1.3 and 7.2 ± 1.5 mm, respectively, P = 0.678).

No intraoperative complications were seen. One dog belonging to the control group had a seroma in the 5-mm caudal site the day after surgery which led to a nodule. No other postoperative complications occurred.

Discussion

While the use of small-diameter instruments has already been described for the LapOve in small dogs (2), this study highlights its use and describes 2 combinations of the conventional instruments and compares them to a control group. The advantages of laparoscopic veterinary surgery are well-known. In particular, LapOve reduces pain (17) improves postoperative activity (2), and provides a better view of abdominal structures without increasing surgical time (13).

A modified Hasson technique (16) was used for abdominal access and establishment of the pneumoperitoneum. Most surgeons prefer this approach for the placement of cannulas to avoid visceral damage (15). This might also be more appropriate for small animals to avoid visceral damage from use of a Veress needle (18). In this study no visceral injury was noted during cannula placement. One of the obstacles that appeared in the 5BF group (2.7-mm telescope) was related to the 3.5-mm cannula, as it was placed without direct visualization. We had slight leakage of CO₂ when we passed the 2.7-mm telescope through the 5-mm cannula to introduce the second cannula with direct visualization, reducing the working space by loss of CO₂. It is possible that these gas losses go unnoticed in largerdogs. In any case, this inconvenience can be prevented by using a rubber reducer that permits the use of the small telescope in the 5-mm cannula.

We tried to adjust the size of the wound as close as possible to the diameter of the 3.5-mm trocar. Using the modified Hasson technique, however, made it difficult to properly fit the cannula sheath to the abdominal wall without extending the size of this portal in order to perform both blunt dissection of the subcutaneous layer and identification of the abdominal fascia.

The mean pressure of pneumoperitoneum used across the 3BF and 5BF groups was 7.6 mmHg (1.5 L CO₂/min mean preset flow and 1.9 L/kg mean spent CO₂), which was less than the 9 to 12 mmHg (2) and 13 mmHg (3,13) and similar to the 8 mmHg (4) described in previous reports to achieve an adequate intra-abdominal working space.

The mean duration of surgery across the 3 groups, including abdominal closure (41 min) was longer than the 19 (4) and 25 min (5) observed in previous studies of LapOve using the 5-mm instruments, and closer to the 30 min (2) when a small telescope (3 mm in diameter) was used. Compared to these previous studies, the differences in total surgical time are greater in the 3BF group (45 min) and less in the 5BF (38 min) and control (39 min) groups. The bipolar forceps with the scissors used in this study showed longer times for resection of the ovaries compared with those observed when either the bipolar or ultrasonic sealer was used (2.1 min using the Ligasure vessel sealing device and 2.6 min using the Sonosurg ultrasonic device) (19). A significant increase in surgical time occurred when the 3-mm bipolar forceps was used compared to the 5-mm bipolar forceps. When surgical stages are analyzed, the time needed for the left and right ovaries differed significantly between the 3-mm and 5-mm bipolar forceps (5BF and control groups, respectively). It stands to reason that the 3-mm forceps coagulates smaller amounts of tissue due to its smaller jaws than the 5-mm forceps, increasing surgical times. Although a different method for removing ovaries was followed in dogs belonging to the 3BF group, no difference in time was seen. The length of the 6-mm portal sites was sufficient, as observed in previous studies (2). Time for closure was longer in the control group compared with the 5BF group. This difference was due to 6 dogs in the 5BF group having times for closure under 5 min while in the control group all dogs had times of 5 min or longer. Although the 3BF group showed no significant differences with respect to the control group for closure, the time saved without suturing the 3.5-mm sites was 3 min. Surgical time for the LapOve is increased 22% in obese dogs and obesity is positively correlated with a large amount of fat in the ovarian pedicle (15). In this study, high FSOP also increased surgical time regardless of the instruments used. In addition, the total surgical time was increased in the 3 groups of dogs with a high FSOP compared to those with a low FSOP, and in dogs in groups 3BF and the control, a large amount of fat affected the time necessary for ovarian resection. Therefore, it is advisable to use the 5-mm bipolar forceps instead of the 3-mm forceps in obese dogs.

Bleeding rates after coagulation and cutting of the ovarian pedicle using different types of instruments have been compared (NDYAG laser versus bipolar forceps, NDYAG laser versus Remorgida bipolar forceps and monopolar forceps versus bipolar forceps) (14,15,20). The effectiveness of bipolar instruments related to coagulation of the ovarian pedicle has been well-demonstrated. In this study, bleeding was always stopped by the bipolar instrument and there were no significant differences in bleeding rates among groups. However, the bleeding rate was lower when the 5-mm bipolar forceps was used compared to the 3 mm bipolar forceps. Higher bleeding rates (50%) were observed in the 3BF group. This combination is therefore not recommended especially for inexperienced laparoscopists.

One limitation of this study was the different viewing angles provided by the telescopes. The angled view of the 2.7-mm telescope makes it harder to use when the surgeon has not been trained in its use, although it gives a bigger working view. The 2.7-mm 30° was chosen because it is an available telescope widely used by veterinarians for the endoscopic exploration of small cavities. Surgeon performance degrades as viewing axis increases from 0° to 180° relative to the working instruments (21). It is well known that small telescopes provide a lower quality of view compared with larger diameter instruments. Blinded observers determined that the laparoscopic view of the 5-mm telescope was vastly superior compared to that of the 2.7-mm telescope. Viewing was inadequate because of the lack of light, followed by the lack of definition and finally the lack of visual field. Although only the best images were sent with the questionnaires, 50% were judged to be of inadequate quality when the 2.7-mm telescope was used, and consequently, this telescope is not recommended for less experienced surgeons.

For closure, the use of only the tissue adhesive on the skin layer in the 3.5-mm portal sites reduced tissue handling and closure time. The tissue adhesive N-butyl-cyanoacrylate has been successfully used for closure of canine LapOve port site incisions (22). No complications such as herniated tissue were observed related to the lack of suture in the abdominal fascia of the 3.5-mm portal sites.

In summary, the 2.7-mm 30° telescope or the 3-mm bipolar forceps combined with conventional 5-mm instruments could be used as an alternative technique for the LapOve in dogs up to 10 kg. The 2.7-mm telescope with the 5-mm bipolar forceps was the most efficient combination based on surgical time. However, because of the reduced vision and the higher number of bleeding events observed with the 2.7-mm telescope and the 3-mm bipolar forceps, respectively, they are not recommended especially for less experienced laparoscopists. Further studies are needed to assess the benefit of the described techniques related to the postoperative activity of the operated dogs when instruments of small diameter are used. CVJ