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Year : 2022  |  Volume : 55  |  Issue : 6  |  Page : 215-220

Comparative study between sublay (retrorectus) and onlay mesh placement in ventral hernia repair at a teaching hospital

Department of General Surgery, Bharati Vidyapeeth (Deemed to be University), Pune, Maharashtra, India

Date of Submission28-May-2022
Date of Decision29-Aug-2022
Date of Acceptance05-Sep-2022
Date of Web Publication22-Nov-2022

Correspondence Address:
Salman Naseem Shaikh
Flat 101, Sai Water Crest, Jambhulwadi Lake Road, Ambegaon Budruk, Pune - 411 046, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/fjs.fjs_123_22

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Background: Anterior abdominal wall defects give rise to ventral hernias. Treatment modalities vary from surgical options such as open procedure, laparoscopic method to further advanced robotic surgeries. The present study aimed to find the comparison between the postoperative and short term outcomes of onlay and retrorectus (sublay) mesh placements as ventral hernia repair methods.
Materials and Methods: Our enrolled ventral hernia patients were divided into two groups of 20 each. Group A underwent traditional open onlay mesh repair and group B had open sublay/retrorectus mesh hernia repair. Age, gender, body mass index, comorbidities, and past surgical history, among both groups, were comparable.
Results: The duration of surgery was significantly shorter in onlay group. The sublay group was related to fewer postsurgical complications and shorter duration of drain insertion. The duration of hospital stay had no statistical significance.
Conclusion: Both techniques have their pros and cons and further research is required to determine a superlative.

Keywords: Hernia repair, onlay repair, sublay repair, ventral hernia

How to cite this article:
Deherkar JA, Borkar PE, Kakade KR, Kharat RS, Shaikh SN. Comparative study between sublay (retrorectus) and onlay mesh placement in ventral hernia repair at a teaching hospital. Formos J Surg 2022;55:215-20

How to cite this URL:
Deherkar JA, Borkar PE, Kakade KR, Kharat RS, Shaikh SN. Comparative study between sublay (retrorectus) and onlay mesh placement in ventral hernia repair at a teaching hospital. Formos J Surg [serial online] 2022 [cited 2022 Nov 26];55:215-20. Available from: https://www.e-fjs.org/text.asp?2022/55/6/215/361698

  Introduction Top

A hernia is the protrusion of an intra-abdominal organ through a defect in the abdominal wall. The majority of defects are present in the inguinal region, femoral region, and anterior abdominal wall. The term ventral hernia describes any hernia due to inadequacy of the anterior abdominal wall muscles.[1] In recent times, there has been a significant rise (13%–23%) in incisional hernias following laparotomy surgeries.[2],[3]

Weakness at the incision site of previous abdominal surgery, secondary to a surgical site infection or a failed surgical repair/mesh placement is the most important precipitating factor causing a ventral hernia. Additional influences include overweight, pregnancy, frequent coughing episodes, severe vomiting, history of lifting or pushing heavy objects, straining while having a bowel movement/urinating, etc.[4]

Ventral hernia treatment modalities vary from conservative management to surgical options such as open procedure, laparoscopic method, and further advanced robotic surgeries. Suturing alone remains acceptable for tiny defects while mesh support is recommended for elective repair of incisional hernias or a primary ventral hernia ≥2 cm in width with no contamination.[5]

The gold standard management of elective ventral hernias is mesh insertion.[2] An increased understanding of the anterior abdominal wall anatomy demonstrated different placements of the mesh. General surgeons chose the onlay – over the rectus mesh repair and sublay – preperitoneal/retrorectus mesh repair as favorites of the open ventral hernia repairs.[6] The present study aimed to find the comparison between the postoperative and short-term outcomes of onlay and retrorectus (sublay) mesh placements as ventral hernia repair methods.

  Materials and Methods Top

The present study was a hospital-based comparative study of two groups, conducted in the Department of General Surgery, at Bharati Hospital, Pune, India. The study duration was of 2 years (September 2019–August 2021). The sample size was calculated using Fisher's exact test. Forty adult patients of both sexes admitted with ventral hernias (including umbilical, paraumbilical, incisional, and epigastric hernias) in the surgical department of a tertiary hospital were included and followed up for a maximum 3 months postprocedure duration in the outpatient department (OPD). Ethical clearance was obtained from the ethical clearance committee of the institution for the study (BVDUMC/IEC/16 on Nov. 11th, 2019).

Inclusion criteria

All adult patients of either gender and with ventral hernias such as postlaparotomy midline incisional hernias and recurrent hernias or primary hernias (umbilical, paraumbilical, or epigastric) are diagnosed on clinical examination.

Exclusion criteria

Patients with peritonitis or inflamed, obstructed, or strangulated hernia, groin hernias, preexisting skin infections at the site of hernia, patients with uncontrolled diabetes mellitus, and chronic obstructive pulmonary disease were excluded from the study.

The eligible patients were briefed about the nature of the study and written informed consent was obtained from the consenting patients' details such as demographic data, signs, symptoms, predisposing risk factors, investigations, diagnosis, type of operative technique, operative time, and complications (immediate and late) were collected.

After preliminary investigations, confirmation of diagnosis, and preanesthetic checkup, the patients were subjected to the required surgery.

Patients were divided into two groups.

Group A included 20 patients managed by traditional onlay mesh repair.

Group B included 20 patients managed by sublay (retrorectus) mesh repair.

The patients then underwent the following procedure as per their group. The decision of mesh placement was decided by the operating surgeon intraoperatively. All patients were given intravenous antibiotics prophylactically: cefuroxime 1.5 g intravenous single dose at the time of induction of anesthesia and cefotaxime 1 g intravenous 12 h for 5 days postoperatively. A closed wound suction drain was inserted in all cases. No external compression was done.

The time taken from initial skin incision to skin closure with complete hemostasis was recorded. Check dressing was carried out after 72 h. Assessment of wound infection if present, was done as per the Southampton scoring system. A wound inspection was done and observations were recorded as per the criteria. The drain was removed when discharge was <10 ml in 24 h. Patients were followed up in OPD for a maximum duration of 3 months. Southampton wound grading system was used for grading surgical site infections (SSIs).

All the data were noted down in a predesigned study pro forma. Qualitative data were represented in the form of frequency and percentage. Association between qualitative variables was assessed by Chi-square test with continuity correction for all 2 × 2 tables and Fisher's exact test for all 2 × 2 tables. Quantitative data were represented using mean ± standard deviation. Analysis of quantitative data between the two groups was done using an unpaired t-test. A P < 0.05 was considered a level of significance.

  Results Top

Out of 40 patients with a ventral hernia, patients were divided equally into two groups based on the procedure followed for placement of mesh in hernia repair, namely, onlay and sublay. Each group had 20 patients. The mean age was 48.13 ± 11.71 years. There were 27 (67.5%) females and 13 (32.5%) males. The mean value of body mass index (BMI) was 27.15 ± 4.04 kg/m2, the mean duration of surgery was 145.25 ± 53.11 min, the duration of the drain was 6.83 ± 3.01 days, and the pain score was 4.60 ± 0.81. The demographics of all included patients were listed in [Table 1].
Table 1: Patient demographics (n=40)

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The demographic and clinical parameters were compared between the groups of placements of mesh, age, gender, BMI, comorbidities, and past surgical history, among both groups, were comparable and the difference was not significant statistically (P < 0.05). Tubal ligation (30%), lower-segment cesarean section (25%), and exploratory laparotomy (20%) were common past surgical events noted in the present study. The above data are summarized in [Table 2].
Table 2: Comparison of demographic and clinical parameters among study groups

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The duration of surgery required in sublay group was 169.75 min ± 59.75 min, whereas in onlay it was 120.75 min ± 30.92 min; it differed significantly (P < 0.0001) among the groups. The duration of drain also differed significantly (P = 0.03) with the mean value of 7.85 ± 3.10 and 5.80 ± 2.61 days in onlay and sublay groups, respectively. No significant difference was noted for the day of discharge and pain score among the groups. The above data are summarized in [Table 3].
Table 3: Surgical Characteristics

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Although nonsignificant, there was a higher incidence of high severity SSIs as per the Southampton wound scoring reported in onlay group than sublay group (10 vs. 4). There was only one patient in sublay group with a high score, as compared to onlay with seven patients [Table 4].
Table 4: Incidence of surgical site infection as per the Southampton wound scoring among study groups

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The distribution of patients according to complications including seroma, wound edge necrosis, and wound hematoma did not differ significantly between the onlay and sublay groups. The most common postoperative complication recorded was wound edge necrosis followed by seroma. Although nonsignificant, the number of patients with seroma was higher in the onlay group as compared to the sublay group. The above data are summarized in [Table 5].
Table 5: Distribution of patients according to postoperative complications among two procedure groups

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Most of the patients in both groups had a score of <5 pain score as onlay (90%) and sublay (85%). The above data are summarized in [Table 6].
Table 6: Distribution of patients according to pain score among two procedure groups

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  Discussion Top

A ventral hernia is an acquired defect in over 90% of adults. It is a frequently encountered clinical predicament which is infrequently discussed critically in the medical literature. The umbilicus, being one of the potential weak areas of the abdomen, is a common site of herniation. “Paraumbilical hernia” describes a midline hernia occurring through the linea alba adjoining superiorly or inferiorly on the umbilicus.[7]

These hernias have the potential of developing from simple swelling to obstruction and strangulation. Persistent strangulation of the tissue causes loss of blood supply, leading to gangrene formation and further life-threatening complications.[8]

The primary aim of hernia surgery is to obliterate the defect in the abdominal wall with a sound and tension-free repair to minimize the risk of recurrence. The use of prosthetic mesh has superseded the traditional open suture method to reduce recurrence risk.[9]

The duration of surgery was significantly lesser in onlay repair compared to sublay repair, whereas the duration of the drain was statistically lower in sublay mesh group compared to onlay. The age, BMI, day of discharge, and pain score did not differ among the groups. There was an insignificantly higher incidence of seroma, wound edge necrosis, and SSIs in onlay group as compared to sublay.

Reddy et al.[10] studied 50 patients with incisional hernia with the majority of subjects belonging to 31–40 years, and 30 patients were males and 20 were females. The duration of hospitalization was substantially less in sublay group compared to onlay.

The means of age and gender did not differ among onlay and sublay groups in a study by Kharde et al.,[11] with no difference in the operative time, the mean of operative time in onlay group was 69.8 min ± 12.20 min, whereas in sublay group it was 77.8 min ± 10.71 min. Cai et al.[12] evaluated 10 patients in incisional hernia of which seven were males and three were females, with a mean age of 45.7 years, BMI of 25.5 kg/m2, and mean postoperative hospital stay was 2.2 days ranging between 1 and 4 days. Visual analog scale score as a marker of pain yielded good results with a median value of 2.

In a study using sublay technique in incisional hernia patients by Schembari et al.,[13] mean age and mean BMI of patients were 58 ± 13 years and 27 ± 12.5 kg/m2, respectively. The mean hospital stay was 5.9 ± 2.1 days, which was low as compared to the present study. As compared to the present study, comparable demographic parameters were recorded by Al-Tai,[14] with a significant difference in the mean duration of surgery and time of drain removal between sublay and onlay groups.

Complications of enlarging incisional hernias include pain, discomfort, bowel obstruction, incarceration, and strangulation. They also reduce patients' quality of life. There is a considerable reduction in recurrence after a mesh repair (32%) in contrast to open suture repair (54%).[15]

Owing to the high recurrence rate and postoperative morbidity, repair of incisional hernia is knowingly recognized as a difficult general surgical procedure. Suture repair is inferior to open mesh repair (onlay and sublay approach). However, due to the presence of mesh, this approach is not without risk of morbidity, including wound complications such as seroma development and infection.[16]

The prosthetic mesh can be placed between the subcutaneous tissues of the abdominal wall and the anterior rectus sheath (onlay mesh repair) as well as in the preperitoneal plane created between the rectus muscle and posterior rectus sheath (sublay mesh repair). The latter technique has several advantages, one of which is that it does not transmit the infection from subcutaneous tissues to the mesh as it lies quite deep in the preperitoneal plane.[17] Furthermore, two meta-analyses suggested sublay mesh repair over onlay mesh repair for incisional hernias, as it is associated with a low incidence of postsurgical complications.[18],[19]

Although nonsignificant, there was a higher incidence of high severity SSIs as per the Southampton wound scoring reported in onlay group than sublay group (10 vs. 4). Al-Tai et al.,[14] wound infection was noted in one and six patients in sublay and onlay group, respectively. Wound edge necrosis in onlay repair was observed in only one patient, whereas there was no case of flap edge necrosis in sublay group. Venclauskas et al.[20] conducted a randomized control trial to assess the rate of SSI between the onlay and sublay groups; they observed that the sublay approach had a statistically significant lower risk of SSI than the onlay technique.

In contrast to these findings, Saeed et al.[21] published a retrospective study revealing that the sublay group has a considerably higher rate of wound infection than the onlay group.

Four studies, including two randomized controlled trials, (Sevinç et al.,[22] Ahmed et al.,[23] Kumar et al.,[24] and Gleysteen[25]) discovered no statistically significant difference in SSI risk between only and sublay mesh repair. Hatata et al.[26] reported three cases of superficial SSI in the onlay group versus one in the sublay group. In addition, one instance of retrorectus hematoma occurred in the sublay group, and one case of skin flap necrosis occurred in the onlay group with no statistical significance.

The most common postoperative complication recorded was wound edge necrosis followed by seroma. The wound edge necrosis was equally distributed among both groups. Although nonsignificant, the number of patients with seroma were more in onlay than sublay group.

Similar to the present study where seroma was nonsignificantly high in onlay compared to sublay group, Kovvuri et al.[10] and Al-Tai et al.[14] reported postoperative complications seroma which was significantly high in onlay as compared to sublay group. Leithy et al.,[15] apart from seroma SSI and recurrence of hernia were present equally in both the groups. In umbilical hernias with sublay mesh repair by Cai et al.[16] reported a single case of seroma, without any other wound complications, chronic pain, or recurrence.

Bhat et al.[17] also reported only two patients each having seroma, wound dehiscence, and hematoma. To treat ventral abdominal wall hernias, Jani et al.[27] noted seroma in two patients, who were asymptomatic and managed conservatively, whereas mesh infection or recurrence was noted in none of the patients. As per a meta-analysis, the most common postsurgical complications were wound infection, seroma, hematoma, and recurrence of hernia.[28] While the almost equal distribution of patients with seroma and deep SSI requiring extrusion of mesh was reported by Kingsnorth et al.[9] between onlay and sublay mesh repair techniques.

  Conclusion Top

The sublay mesh repair technique is related to fewer postsurgical complications and also a lesser duration of drain and thus hospital stay. Sublay technique proved predominantly better than onlay technique.

A few limitations of the present study were the issue of selection bias could not be addressed, as the choice of mesh placement technique was left to the discretion of the operating surgeon. Hernia defect size was not taken into consideration. A larger sample size is essential for a more comprehensive analysis with longer follow-up to address issues of delayed wound infections and risk of recurrences of hernia.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Williams NS, Bulstrode CJ, Connell PR, editors. Bailey and Love's Short Practice of Surgery. 26th ed. New York: CRC Press; 2013. p. 948-9.  Back to cited text no. 1
Jaykar RD, Varudkar AS, Akamanchi AK. A clinical study of ventral hernia. Int Surg J 2017;4:2326-9.  Back to cited text no. 2
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Jensen KK, Henriksen NA, Jorgensen LN. Endoscopic component separation for ventral hernia causes fewer wound complications compared to open components separation: A systematic review and meta-analysis. Surg Endosc 2014;28:3046-52.  Back to cited text no. 4
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Chichom Mefire A, Guifo ML. Don't be scared: Insert a mesh! Pan Afr Med J 2011;10:18.  Back to cited text no. 6
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Purushotham G, Revanth K, Aishwarya M. Surgical management of umbilical and paraumbilical hernias. Int Surg J 2017;4:2507-11.  Back to cited text no. 8
Kingsnorth A, Banerjea A, Bhargava A. Incisional hernia repair – laparoscopic or open surgery? Ann R Coll Surg Engl 2009;91:631-6.  Back to cited text no. 9
Kovvuri R, Krishna B, Takalkar A. Onlay and sublay mesh repair in incisional hernias: Our experience from GSL medical college and hospital, Rajahmundry. Int Surg J 2021;8:2607-11. [doi: 10.18203/2349-2902.isj20213183].  Back to cited text no. 10
Kharde K, Dogra BB, Panchabhai S, Rana KV, Sridharan S, Kalyan S. A comparative study of onlay and retrorectus mesh placement in incisional hernia repair. Med J DY Patil Univ 2013;6:258-62.  Back to cited text no. 11
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Cai XY, Chen K, Pan Y, Yang XY, Huang DY, Wang XF, et al. Total endoscopic sublay mesh repair for umbilical hernias. Medicine (Baltimore) 2021;100:e26334.  Back to cited text no. 12
Schembari E, Sofia M, Lombardo R, Randazzo V, Coco O, Mattone E, et al. Is the sublay self-gripping mesh effective for incisional ventral hernia repair? Our experience and a systematic review of the literature. Updates Surg 2020;72:1195-200.  Back to cited text no. 13
Al-Tai AH. Evaluation of “sublay” versus “onlay” mesh hernioplasty in ventral hernial repair. J Pharm Sci Res 2019;11:1313-8.  Back to cited text no. 14
Leithy M, Loulah M, Greida HA, Baker FA, Hayes AM. Sublay hernioplasty versus onlay hernioplasty in incisional hernia in diabetic patients. Menoufia Med J 2014;27:353-8.  Back to cited text no. 15
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Bhat MG, Somasundaram SK. Preperitoneal mesh repair of incisional hernia: A seven year retrospective study. Indian J Surg 2007;69:95-8.  Back to cited text no. 17
Timmermans L, de Goede B, van Dijk SM, Kleinrensink GJ, Jeekel J, Lange JF. Meta-analysis of sublay versus onlay mesh repair in incisional hernia surgery. Am J Surg 2014;207:980-8.  Back to cited text no. 18
Köckerling F. Onlay technique in incisional hernia repair – A systematic review. Front Surg 2018;5:71.  Back to cited text no. 19
Venclauskas L, Maleckas A, Kiudelis M. One-year follow-up after incisional hernia treatment: Results of a prospective randomized study. Hernia 2010;14:575-82.  Back to cited text no. 20
Saeed N, Iqbal SA, Shaikh BA, Baqai F. Comparison between onlay and sublay methods of mesh repair of incisional hernia. J Postgrad Med Inst 2014;28:400-3.  Back to cited text no. 21
Sevinc B, Okus A, Ay S, Aksoy N, Karahan O. Randomized prospective comparison of long-term results of onlay and sublay mesh repair techniques for incisional hernia. Turk J Surg 2018;34:17-20.  Back to cited text no. 22
Ahmed M, Mehboob M. Comparisons of onlay versus sublay mesh fixation technique in ventral abdominal wall incisional hernia repair. J Coll Phys Surg Pak 2019;29:819-22.  Back to cited text no. 23
Kumar V, Rodrigues G, Ravi C. A comparative analysis on various techniques of incisional hernia repaired experience from a tertiary care teaching hospital in South India. Indian J Surg 2012;75:1-3.  Back to cited text no. 24
Gleysteen JJ. Mesh-reinforced ventral hernia repair: Preference for 2 techniques. Arch Surg 2009;144:740-5.  Back to cited text no. 25
Hatata Y, Shaaban N, Al-Gaabari T, Shaaban M. Onlay versus sublay mesh repair in the management of uncomplicated ventral abdominal wall hernias. Fayoum Univ Med J 2019;3:71-82.  Back to cited text no. 26
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Chaouch MA, Dougaz W, Daghmouri M, Jerraya H, Khalfallah M, Bouasker I, et al. Onlay versus sublay mesh repair of open ventral incisional hernia: A meta-analysis of randomized controlled trials Review. Clin Surg Res Commun 2020;4:1-9. doi: 10.31491/CSRC.2020.06.049.  Back to cited text no. 28


  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]


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