Comparison of Right Flank and Caudal Midline Approaches for Ovariectomy in Gilts

To evaluate the two different approaches to accomplish ovariectomy in gilts was used. The animals were randomly divided into two equal (n = 6) groups of Flank and Midline. Ovariectomy was performed by the right flank approach in group flank and by the caudal midline approach in group Midline. In the present study surgical, physiological, haematological parameters, postoperative pain scoring, healing time and wound score were assessed. Bleeding was noticed in group Flank compared to group Midline due to surgical trauma to the muscles. The duration of surgery was 43.33±4.08 and 55.83±5.84 minutes and length of surgical incision was 5.03±0.37 and 5.87±0.35 cm in Group Flank and Midline respectively. Post-operative swelling and erythema were noticed in group Flank compare to group Midline. The time taken for the surgical wound to heal was 9.33±0.81 and 10.83±0.75 days in group Flank and group Midline respectively. There was no significant variation in physiological parameters like heart rate, respiratory rate and rectal temperature in both the groups and within the groups of different periods. There was no significant variation in haematological parameters like haemoglobin and PCV in both the groups except for TLC in group Midline. Based on the observations and evaluation made during the present study, it was concluded that no clinical and haematological alterations were observed in gilts undergoing open ovariectomy (OVE) through the caudal midline and right flank approach. Therefore, both the right flank and caudal midline approaches could be implemented effectively for ovariectomy in gilts. However, the flank approach was less time consuming and the length of surgical incision was comparatively less to the caudal midline approach. Hence, the results show that the right flank approach can be a good alternative to the caudal midline approach for ovariectomy in gilts.

Ovariectomy in a pig is a very common surgical procedure in Mizoram and it was reported that the ovariectomized pigs grow better, yielding improved quality meat (Saikia et al. 2013). Conventional OVE (COVE) in pig mostly is achieved through caudal midline celiotomy for an easy approach to both the ovaries. But on caudal midline celiotomy, there is a high possibility for post-operative incisional hernia.
The incidence of the evisceration of abdominal organs or other catastrophic consequences is more in ventral midline incision as compared to the flank approach due to the breakdown of incision line because gravitational forces exerted on midline incision (McGrath et al. 2004). In addition to this, in the state of Mizoram ventral midline incisional hernia mostly encountered as a postoperative complication of spaying (Saikia et al., 2009). Thus lateral flank approach was proposed as an alternative to the conventional ventral midline ovariohysterectomy.

MATERIALS AND METHODS
Twelve healthy gilts were brought to Teaching Veterinary Clinical Complex, College of Veterinary Sciences & Animal Husbandry, Central Agricultural University, Selesih, Aizawl, Mizoram for ovariectomy which was randomly divided into two groups viz. Group Flank and Group Midline and each groups consisting of six animals. The animals in both groups were preanaesthetized by Diazepam @2mg/kg BW, I/V and then anaesthetized by Ketamine@15mg/ kg BW, I/V (Konwar and Saikia, 2006).

(A) Right flank approach
After preparing the surgical site on the right flank region, the animals were controlled on left lateral recumbency and incision was made on the right flank position in a dorsoventral direction 2 to 3 cm below the transverse process of lumbar vertebrae (Fig.1A). Once the abdomen had been opened, most of the time the ovary or uterine horn was exposed just below the incision. The ovary or uterine horn was grasped with forceps and delivered through the incision similar to the ventral midline approach. The uterine horn was elevated to expose the bifurcation and contra-lateral uterine horn, which was grasped  and traced cranially until the ovaries were identified (Fig.1B). The ovarian pedicles were ligated and the ovary was severed distal to the sutures and checked for hemorrhage (Fig.1C). After removal of both the ovaries, peritoneum, muscle, subcutaneous was sutured. And finally, closure of skin incision was done by interrupted horizontal mattress sutures using 2-0 nylon monofilament (Fig.1D).

(B) Caudal Mid ventral approach
Gilts were placed in dorsal recumbency. After the preparation of the surgical site on the ventral midline, a standard skin incision was made in between the last pair of the teat ( Fig.2A). Laparotomy was achieved after incising subcutaneous tissue, linea alba, and peritoneum. A snook ovariectomy hook was used to gain exposure to the uterus and then to each ovary (Fig.2B) by applying traction on the suspensory ligament. A 2-forceps technique was used to ligate each ovarian pedicle with 1 ligature. The pedicle was transected and proper ovarian ligament was ligated with No.2/0 Chromic Catgut. The ovary was severed distal to the sutures and checked for haemorrhage ( Fig.2C). After the excision of both ovaries, the uterine body was released into the abdomen. Finally, the peritoneum, linea alba, and subcutaneous tissue were closed by using simple continuous sutures of No.1 Chromic Catgut. Closure of skin incision was done by interrupted horizontal mattress sutures using 2-0 nylon monofilament (Fig.2D). Blood loss during operation: Blood loss was measured as per method described by Eipe and Ponniah (2006).

(B) Physiological parameters:
Heart rate (HR) (beats/min), Respiratory rate (RR) (breaths/ min) and Rectal temperature (RT) (˚C) were recorded before administration of anaesthetic agent (before surgery) then every day up to 7 th postoperative day.
(C) Haematological study: The blood samples (2ml) were collected from ear veins or anterior vena cava, in dry vials containing K3EDTA before administration of anaesthesia (baseline) (BS), then every day up to 7 th postoperative day for the estimation of Haemoglobin (Hb g/ dl), Packed Cell Volume (PCV %) and Total Leukocyte Count (TLC × 10 3 /cu.mm) using automated haematology cell counter (MS4e, Netherland) .
(D) Post-operative pain scoring: Post-operative pain scoring was done as per the score card described by Viscardi et al. (2017) with Piglet Grimace Scale from day 0 to day 7 after the surgery.

(E) Healing time of surgical site (days) and wound scoring:
The clinical appearance/ gross changes of the wound were scored at 0 to 14 th day post-surgery. The wound was scored based on swelling, erythema, dehiscence, and discharge as suggested by Sylvestre et al. (2002).
Statistical analysis was carried out by SPSS version 20 with a one-way Analysis of Variance (ANOVA) and t-test.

(A) Surgical parameters (i) Surgical time
The mean total surgical time in Group Flank (43.33 ± 4.08) was significantly ((P≤0.01) less as compared to Gr. Midline (55.83 ± 5.84). It might be due to that genital organs could be immediately accessed in the flank method as compared to the ventral midline approach (Hansen, 2005). Similarly, Rana (2007) also reported that the duration of operation was significantly less in cats operated through flank (24±2.65 min) approach than the midline (29±3.51 min).

(ii) Incision length
In regards to surgical incision length, it was observed that group flank was (5.03 ± 0.37cm) significantly shorter than the midline approach (5.87 ± 0.35 cm). This finding is correlated with Kiani et al. (2014). Kiani et al. (2014) reported that the subgroup-Fa was incised with a shorter length (2.82 ± 0.13 cm) than that of subgroup-Ma (2.88 ± 0.23 cm) for ovariohysterectomy. It might be because it was easy and convenient to provide better accessibility and localization as compared to the midline approach (Rana, 2007).

(iii) Blood loss during operation
During operation, the mean total blood loss was significantly (P≤0.01) more in Group Flank (55.83 ±7.35 ml) as compared to Group Midline (26.83 ± 2.78 ml). This could be due to the presence of high vascular channels in the abdominal muscle mass when compared to poor vasculatures associated with tendon and ligament in the linea alba. This finding was in line with the finding of Abubakar et al. (2014).

(B) Physiological parameters:
There was no significant variance in heart rate, respiratory rate and rectal temperature in both the groups in different periods as well as within the groups. This is in line with the observations of Hancock et al. (2005), Kumar (2006) and Holey (2010) who have also recorded similar results during their investigation.

(C) Haematological study
The mean values of haemoglobin and PCV recorded in different periods of observation did not show any significant difference (P> 0.05) on comparison either between the groups or between the periods in the same groups (Table  1) Values were non-significantly (P>0.05) decreased on day 1 in both the groups as compared to day 0 and then gradually increased towards the baseline value in both the group Flank and group Midline. The results of the present study are in line with the findings of Kumar et al. (2014). The decline in the values could be attributed to the splenic pooling of erythrocytes during anaesthesia. (Tiwari, 2015) or might be due to the intraoperative blood loss during the time of surgery (Khandekar, 2011).
The mean values of total leukocyte count recorded in different periods of observation did not show any significant difference (P> 0.05) on comparison within the periods in group Flank (Table 1). But significant variations (P≤ 0.01) were observed within the periods in group Midline. Also, a significant difference (P≤ 0.01) was observed between both the groups except on day 0. In group Midline, total leukocyte count was significantly (P≤ 0.01) increased on day 1 as compared to day 0 and then gradually decreased to reach the baseline value on day 7. The results were similar to Laiju et al. (2011) and Fazio et al. (2015) who also observed in conventional ovariohysterectomy in dogs. Dharmaceelan et al. (2000) also reported a significant increase in total leucocyte count on a first post-operative day which might be due to tissue trauma during surgery resulting in increased leucocytes in the peripheral blood and produced stress leukogram pattern (Rebar, 2004) in complete blood count.

(D) Post-operative pain scoring
A significant difference (P≤0.05) was recorded between the groups on different observations in both group flank and midline (Fig. 3). Significantly decreased (P≤0.05) mean postoperative pain score was observed in group flank as compared to group midline on Day 0, Day 1, Day 2 and Day 3 and non-significantly decreased (P>0.05) value was observed on all other periods of observation. This finding is almost as per Viscardi et al. (2017). Any difference in post-operative pain between two approaches might be due to differences in the sensitivity of the skin of the flank and midline region (Burrow et al. 2005). Considering the results it could also be due to gravitational forces acted upon abdominal organs exerted on caudal midline incision are higher than those on the right flank incision.

(E) Healing time of surgical site (days) and wound scoring
The mean healing time of the surgical site was significant ((P≤0.05) less in Group Flank (9.17 ± 0.75 days) than Group midline (10.17 ± 1.47 days). Similar results were observed by Kiani et al. (2014) and Rana (2007) who also reported that wound healing was better and faster in the flank approach as compared to the ventral midline approach. Non-significant faster healing in the flank approach in the present study as compared to the midline approach might be due to smaller incision and better circulation of muscles of the flank area as compared to linea alba.
The wound was recorded based on swelling and erythema (Table 2) and was scored at 2-time points: 18 to 24 hrs and 10 to 14 days postsurgery. No significant difference (P>0.05) was found between the groups for both swelling and erythema. In the present study, a nonsignificant difference of swelling and erythema both at 18-24 hrs and 10-14 days after surgery with flank approach having the highest score and this might be a result of surgical trauma caused by the traumatic surgical instruments on the soft tissue in the course of surgery. This finding is consistent with the studies conducted by Sylvestre et al. (2002) and Abubakar (2012) where significant differences among the variables were observed.

CONCLUSION
Considering all these observations from the present study, it is concluded that no clinical and haematological alterations were observed in gilts undergoing conventional open ovariectomy (COVE) through the caudal midline and right flank approach. Therefore, both the right flank and caudal midline approaches could be implemented effectively for ovariectomy in gilts. However, the right flank approach for ovariectomy was found to be better in terms of operative timing, incisional length, pain and healing over the caudal midline approach.