Introduction

Laparoscopic techniques are being used increasingly in the repair of abdominal wall hernias, and it is gaining popularity among minimally invasive surgeons, since this approach promise better results than open repair [1–3], such us shorter lengths of hospital stay, a decreased local morbidity compared to conventional open repair, specially surgical site infection [4], and better cosmetic results. On the other hand, it is not well defined if laparoscopic ventral hernia repair (LVHR) could offer lower recurrence rate than open approach (OVHR), although a systematic review of the literature published in 2008 shows results in favor of LVHR versus OVHR in terms of recurrence rate [2]

Different complications have been described as potential risks of LVHR [5, 6], such as enterotomy, intra-abdominal bleeding, postoperative ileus, delayed bowel injury, chronic pain, trocar-site hernia, late mesh infection, symptomatic mesh bulging, ranging their rate from one series to another. The definitions of the parameters used to set the rate of these complications are traditionally well stabilized, and they are based on objective facts. But on the other hand, seroma has been included in different series as one of the main complications of this approach, although the criteria used to evaluate its presence, or even to consider them a complication, have not been defined yet.

Incidence of seroma

Seroma formation has been documented as one of the most common complications after laparoscopic inguinal [7] and ventral hernia repair (Fig. 1), but in most of the cases these seromas must be considered just an incident since they do not cause any problems neither discomfort to patients. The real incidence of seroma after this procedure is difficult to be determined, not being properly documented and analyzed since its presence is highly variable from one series to another. Different studies have shown how the rate of seroma formation is as low as 0.5 % [8] ranging different series from 0.5 [8] to 78 % [9] (Table 1), being the rate described in the systematic review published by Bedi et al. of 5.4 % [10]. But these data are related to the presence of clinical seroma based on different criteria, since one of our studies and the study conducted by Susmallian et al. [11] show that seroma is present in radiological examinations in almost all cases (Table 2).

Fig. 1
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Seroma after laparoscopic repair of a suprapubic hernia

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Table 1 Clinical incidence of seroma alter laparoscopic ventral hernia repair
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Table 2 Radiological incidence of seroma after laparoscopic ventral hernia repair
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One of the main problems related to the variety of these results is that seromas have been considered following different criteria by different authors. For some authors, it is considered just a complication [12], for others it is considered one of the main complications of this technique [13], or even as the most common sequel of this surgery [14], but others just think it is a minor complication [3] or an incident [9].

On the other hand, an additional problem related to the definition of seroma is observed in most of the series: authors have been using different parameters to quantify the rate of seroma formation, or the ones used are difficult to be measured. Some authors have used the definition of “significant seroma” [15] or “prolonged seroma”, while others describe seroma as a fluid retention that requires surgical intervention [16] or need to be punctured [17], or based on the time lasting after surgery, lasting more than 4 weeks [18], more than 6 weeks [19], or even more than 8 weeks [20], or even they are just defined them as “a symptomatic seroma” [21], or by the presence of complications such as seroma-related cellulites [22].

For that reason, we propose a clinical classification of seroma after LVHR in order to unify different criteria, so we can establish in the near futures in the surgical literature the proper incidence of seroma and the clinical importance of it (Table 3).

Table 3 Classification and definitions of clinical seromas after laparoscopic ventral hernia repair
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Importance of seroma formation

Seroma, defined as a serous fluid retention between the mesh and the anterior abdominal wall, is presence in most of the cases after LVHR, as different series that have analyzed its presence by radiological examination shows. Its presence cannot be considered a complication since patients do not even feel them in most of the cases. For these reasons, it is important to establish that seromas must be considered an incident after this surgery that may lead to complications.

The potential complications related to seroma formation include pain, discomfort to the patient, cellulites [22], being the most important complication of the possibility of getting infected. The infection of the seroma is considered one of the most challenging complications since it might lead to mesh removal [22] and recurrence [23].

The rate of cellulitis and infection also ranged from one series to another. Seroma-related cellulitis is considered by some authors to be a common problem that it is present in all the patients in whom a seroma is detected [22]. This cellulitis can lead to mesh infection, postoperative morbidity, and further need for operative care. Some authors have proposed the administration of 7 days of postoperative prophylactic antibiotics to decrease the rate of patients with seroma developing cellulitis [22].

Seroma after LVHR could also be related to recurrences. The weight of this serous fluid between the mesh and the anterior abdominal wall could increase the tensile strength at the fixation site of the mesh and therefore detach tackers (Fig. 2). This fact could be responsible of an inaccurate anchorage of the mesh right after surgery, which may influence the presence of recurrences in the future. In fact, some authors have observed at re-operation because of recurrence how they appeared to be due to mesh detachment, and this fact might be related to the presence of a seroma [23].

Fig. 2
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Seroma could be related to recurrence, since it could desattach the tacks due to its weight

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It is difficult to know, based on the literature, the best method to manage patients presenting seromas and theirs complications in the postoperative period. While some groups recommend puncturing the seroma just in case of pain or discomfort, other groups recommend not doing it in order to avoid contamination. Most of the authors considered spontaneous resolution of seroma occurs in the vast majority of the cases, being not necessary to puncture any of them or being very low the rate of those that need to be aspirated. But we have also detected in the literature that the reasons that lead different authors to puncture seromas and the complications of this invasive approach are not well defined. Based on this data, we have observed that the rate of seromas that are punctured ranges from one author to another, from 0 to 33.3 % [20, 24].

The real importance of seroma formation and the influence of them in the quality of life in the postoperative period of the patients also need to be determined. Analyzing our results, in which only 3 seromas (2.1 % of our published series) need to be punctured due to discomfort to the patients with no further complications [17], we can conclude that seroma is not really a key factor in the postoperative period after this surgery and its simple presence cannot be considered a complication.

But it is our opinion that it would be better to avoid seromas since they could be responsible, in some cases, for some sort of discomfort to the patient and because they could also be responsible for confusion to both patients and surgeons about a possible recurrence.

Classification

We have classified clinical seroma into 5 groups, ranging from 0 to IV. We have to consider that, as we have described previously, the incidence of radiological seroma is almost present in a 100 % of the cases [11], being that reason what leads us to base this new classification just on clinical findings.

The first concept we have to establish is the definition of non-complicated clinical seroma, since it could be considered by different authors in different senses. Non-complicated clinical seroma could be defined as “those seromas detected during physical examination of the patient which do not cause any problem, or just a minimum discomfort that allows normal activity.” Based on this definition, and in the need of a medical, an invasive or a surgical therapy to treat them, the 5 groups (0 to IV) established are (Tables 3, 4):

Table 4 Sub-classification of clinical seromas after laparoscopic ventral hernia repair
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  • Type 0: no clinical seroma

    • Type 0a: neither clinical nor radiological seroma

    • Type 0b: no clinical seroma, but it can be detected by radiological examinations

  • Type I: clinical seroma lasting less than 1 month.

  • Type II: Clinical seroma lasting more than 1 month: seroma with excessive duration.

    • Type IIa: between 1 and 3 months

    • Type IIb: between 3 and 6 months

  • Type III: Minor seroma-related complications: symptomatic seromas that may need medical treatment. Minor complications include:

    • Type IIa: clinical seroma lasting more than 6 month

    • Type IIIb: Esthetic complaints of the patient due to seroma

    • Type IIIc: Important discomfort that does not allow normal activity to the patient

    • Type IIId: Pain

    • Type IIIe: Superficial infection with cellulitis

  • Type IV: Mayor seroma-related complications: seromas that need to be treated. Mayor complications include:

    • Type IVa: Need to puncture the seroma to decrease symptoms

    • Type IVb: Seroma drained spontaneously (applicable to open approach)

    • Type IVc: Deep infection

    • Type IVd: Recurrence related to seroma

    • Type IVe: Mesh rejection related to seroma

The reason why it has been established the division within group I and II in 1 month is because in a standard setting of follow-up most of these patients are reviewed 4–5 weeks after surgery, and seroma is being evaluated at that visit.

It is important to establish when a seroma would be considered an incident or a complication, since its importance would be totally different. Types I and II would be considered an incident, while Types III and IV would be considered a complication, since a medical or invasive therapy is necessary.

In Type IVa, we should also include other surgical treatments such as injection of talc or surgical excision (in case of absence of mesh infection/rejection or recurrence).

On the other hand, it is important to underline that the highest classification is the one that should be used; for example, short duration but a symptomatic seroma is Type III, and short duration but the seroma needs to be punctured should be classified as Type IV.

Discussion

There is a need in the literature to establish a new classification of seromas after LVHR since most authors use this term to define different clinical situations in the same way, which leads to confusion to determine their rate, adding also difficulties to evaluate the effectiveness of the different methods proposed to avoid seroma formation. In this sense, different methods have been described to decrease the rate of this serous fluid between the mesh and the sac, such us cauterization of the hernia sac [25, 26], use of argon bean or to excise it, and to decrease the seroma-related complications, such us the use of postoperative antibiotics to decrease the incidence of seroma-related cellulites in order to decrease the possibility of mesh removal due to this problem [22]. Other authors have proposed that defect closure confers a strong advantage in LVHR, since there is a shift of the paradigm toward more physiologic abdominal wall reconstruction, while providing reliable hernia repair, the addition of defect closure in these patients essentially eliminated postoperative seroma. These authors advocate routine use of the closure of the defect technique during LVHR [15]. But for other authors, such a Palanivelu et al. [12], this maneuver of closing the defect seems to have no influence in the rate of seroma formation.

The evaluation of the effectiveness of these techniques is not the same from one study to another, since the definition used is different by different authors. Since new methods and new studies should be conducted to try to decrease the incidence of these seromas, it would be very important to base the results on this classification, which will help surgeons to better understand the effectiveness of the different methods used to decrease this local incident or complication.

On the other hand, since most of seromas are asymptomatic, there is a need to determine when a seroma would be considered just an incident or a complication. Some series include in the morbidity associated with LVHR the rate of seroma, being most of them just an incident since they can just be detected in the physical examination of the patient, being otherwise asymptomatic. This new classification will be very useful for surgeons in order to determine the percentage of seroma after LVHR that can be considered an incident, which will show a more realistic morbidity rate after this procedure.

Finally, we consider that this new classification could also be used to evaluate the presence of seroma after conventional open ventral hernia repair, since the same criteria can be followed in order to describe and evaluate this local incident or complication. In fact, it is necessary to evaluate the true incidence of seroma when the open and the laparoscopic approach is compared. Different prospective studies show different results, such as the study from Pring et al. [27] in which the rate of seroma is similar among the two approaches, or the study from Barbados et al. [3], in which seroma in more frequent after LVHR, or the study from Kaafarani et al. [20] in which seroma is more frequent after the open approach. On the other hand, there are also different studies [28] and a systematic review on mesh being used for LVHR [29], which compare the incidence of seroma depending on the mesh placed intraperitoneally, being also useful to establish the rate of seroma based on similar criteria.

As a conclusion, it can be said that seroma is one of the most common worries for surgeons that occurs after LVHR, although its real clinical incidence is variable since it has been described in the literature following different parameters. Seromas are observed in almost all cases by radiological examinations, but it is not determined whether they must be considered an incident or a complication. For these reasons, a new classification of seroma has been proposed in order to unify criteria among surgeons when describing their experience. This classification could be also used in the future to measure the effect of new methods proposed to reduce seroma formation to evaluate the incidence of seroma depending on the mesh used, and it could be also proposed to be used to describe the incidence of seroma after open ventral hernia repair.