Modified Stoppa Approach versus Ilioinguinal Approach for Anterior Acetabular Fractures; A Systematic Review and Meta-Analysis

Abstract

Introduction:

Modified Stoppa approach was introduced as an alternative to ilioinguinal approach for management of anterior fractures of acetabulum in order to reduce complications of the latter. However, the efficacy of either approach over other is not well established. The aim of this meta-analysis is to compare the efficacy of modified stoppa and ilioinguinal approach in the management of acetabular fractures in terms of a) quality of reduction achieved b) complication rates c) functional outcomes d) operative time e) intra-operative blood loss.

Methods:

Databases of PubMed, EMBASE and Cochrane registry of controlled trials were taken into consideration for studies on modified Stoppa approach versus Ilioinguinal approach group for the treatment of anterior acetabular fractures. Dichotomous variables were presented as risk ratios (RRs) /Odds Ratio (OR) with 95% confidence intervals (CIs), and continuous data was measured as mean differences, with 95% CIs.

Result:

Four studies involving 375 patients were included in this meta-analysis. Out of those 375 patients, 192 were managed with ilioinguinal approach and 183 were managed with modified Stoppa approach. Anatomical reduction was significantly higher in Stoppa group (p=0.052, RR=1. 19 (1.02, 1.37), p=0. 90, I2=0%). The complication rate was significantly higher in the Ilioinguinal approach as compared with the Stoppa approach (p=0.01, RR 0.63 (0.44 to 0.91), p=0.73 (I2= 0%). The operative time was significantly shorter with modified Stoppa approach (MD = -48.79 (-80.29 to -17.30), p=0.002). No significant differences were found between the two groups in terms of their functional outcomes (p=0.63, RR 0.96 (-0.80 to 1.15), p=0. 56, I2=0%) and blood loss (MD= -212.89 (-476.27 to 50.49) p=0. 06, I2=71%).

Conclusion:

Anterior acetabular fractures, if operated with the modified Stoppa approach were found to have better reduction and lower complication rates with less operative time, when compared to ilioinguinal approach. No significant difference in terms of blood loss was found in both the groups. Further higher quality randomized controlled trials are needed to verify our results.

Introduction

Acetabular fractures are one of the most difficult fractures to manage in orthopaedic surgery. Anatomic reduction of these fracture is necessary to get the optimal result. The ability to get reduction is highly dependent on the ability of surgeon to get good exposure of the surgical field, which in turn is affected by the chosen surgical approach. A good approach is not only just invaluable for obtaining good exposure but also allows anatomical reduction of fracture with a good control over the fracture fragments. It should also cause least possible amount of complications while trying to achieve the same. The ilioinguinal approach has been widely used for internal fixation of fractures of the pelvic ring and acetabulum [1, 2]. Multiple studies have proven its efficacy in approaching anterior acetabular fractures (anterior column fractures, anterior wall fractures, anterior column with posterior hemitransverse fractures, most fractures of both columns, partial transverse fractures, and T-type fractures) [3-5]. However, it is a laborious exposure with an inherent danger to the neurovascular structures (external iliac vessels and femoral nerve) due to their proximity to the surgical plane during the approach [6, 7]. In 1993, Hirvensalo, and later Cole described an extra peritoneal (“Stoppa”) approach through the rectus abdominis muscle as an alternative approach for internal fixation of fractures of the pelvic ring or acetabulum [8, 9]. This technique uses a single window to obtain an intra-pelvic overview of the operative field by maintaining the entire peritoneal sac and its contents, away from the fracture site with some added risk of vascular bleed from the corona mortis or the obturator vessels. However, there is lack of consensus in terms of better overall technique for tackling such fractures. Hence, this meta-analysis aims to compare modified Stoppa and ilioinguinal approach in the management of anterior acetabular fractures with respect to: 1. Quality of reduction obtained.2. Complication rates.3. Functional outcomes.4. Operative time.5. Intraoperative blood loss.

Results

The study flow diagram is illustrated in Figure 1. Four studies involving 375 patients were included in the meta-analysis, with individual sample size ranging from 36 to 225 patients [12-15]. The literature screening process is listed in Figure 1. Of these 321 patients, 171 were managed with ilioinguinal approach and 150 were managed with Modified Stoppa approach. Table 1 summarizes the characteristics of the included studies. By using Jadad scale quality assessment was done. Among four studies, one study was of higher quality and rest of three were of lower quality.

Fig. 1.

Showing the literature screening process

Table 1.

Characteristics of the included studies

Study	Study type	Mean age		Sample		Follow up (months)	Jaddad score
		Stoppa	Ilioinguinal	Stoppa	Ilioinguinal
Ma et al. [15]	RCT	41(33-65)	42(31-62)	30	30	34	4
Elmadag et al.,[13]	Casecontrolstudy	49.3	52.1	17	19	33	1
Hammad et al.,[12]	Retrospective chartreview	32.14(+13.53)	32.12(+ 11.29)	21	33	12	1
Shazar et al.,[14]	Retrospectivestudy	41.88(+15.7)	41.4(+15.4)	103	122	24	1

 Reduction qualityThree studies reported reduction quality according to Matta's criteria. Fractures achieving anatomical reduction were significantly higher in Stoppa group (p=0.02, RR=1. 19 (1.02, 1.37); heterogeneity X2= 0.90, p=0. 02, I2=0%) (Figure 2, Showing reduction quality significantly higher in Stoppa group).

Fig 2.

Showing reduction quality significantly higher in Stoppa group

 Functional outcomeThree included studies reported on the comparable clinical outcomes. No significant differences were found between these two groups; RR 0.96(0.80 to 1.150.02 (-0.13 to 0.16), p=0.83, I2=0%) (Figure 3, showing no significant differences in functional outcome between two groups).

Fig 3.

Showing no significant differences functional outcome between two groups

 Complication rateAll four studies provided details of the incidence of complications. The complication rate was significantly higher in the ilioinguinal approach compared with the Stoppa approach (p=0.01, RR 0.63{0.44 to 0.91}) (Figure 4, Showing complication rate significantly higher in the ilioinguinal approach).

Fig 4.

Showing complication rate significantly higher in the ilioinguinal approach

 Operative timeThree studies provided details of operative time. The operative time was significantly shorter with modified Stoppa approach (MD = -48.79 (-80.29 to -17.30), p=0.002). However the result should be interpreted with caution because of significant heterogeneity between the studies p=0.0003, I2=87) (Figure 5, Showing operative time shorter with modified Stoppa approach).

Fig 5.

Showing operative time shorter with modified Stoppa approach

 Blood lossOnly two studies provided details of blood loss. There was no significant difference between the two approaches in terms of blood loss (MD= -212.89 (-476.27 to 50.49) p=0. 06, I2=71%).

Discussion

Ilioinguinal approach has remained the workhorse approach for fixation of anterior acetabular fractures (anterior column fractures, anterior wall fractures, anterior column with posterior hemitransverse fractures, most fractures of both columns, partial transverse fractures, and T-type fractures) since its description. However, it is time consuming, laborious and likely to cause blood loss in addition to posing inherent danger to external iliac vessels and femoral nerve. The combined view through the three windows in this approach permits only a limited view and assessment of the fracture thus often indirect reduction manoeuvres are required. In 1989 Stoppa described a midline approach to repair inguinal hernias using Dacron mesh. He achieved excellent exposure of the true pelvis with this approach [16]. This created an interest in using this approach for acetabular fracture fixation. Surgical incision landmarks and surgical steps of modified stoppa approaches are described in figures 6 (Showing incision landmarks for Modified Stoppa approach) and 7 (Showing surgical exposure for modified Stoppa approach.). Recent studies have reported relatively less blood loss and less operative time with Stoppa approach [17].

Fig. 6.

Showing incision landmarks for Modified Stoppa approach

Fig. 7.

Showing surgical exposure for modified Stoppa approach

This meta-analysis shows that the rates of achieving anatomical reduction by modified Stoppa approach are higher than those achieved by the ilioinguinal approach. The modified Stoppa approach allows adequate reduction of the articular fragment impacted into the weight bearing dome area. It is also suitable for cancellous bone grafting, addition of bone substitute material, fixation of the fractures without lateral extra pelvic exposures and without dislocating the joint. Many authors have reported large series of patients operated by the modified Stoppa approach. Hirvensalo et al. used modified Stoppa approach in 164 cases of pelvic and acetabular surgery, of which 138 (84.1%) had anatomic reduction, 9% were graded as fair and 7% were graded as poor. They found that 80% of patients achieved a Harris hip score of 75 or greater on clinical examination and functional outcome scoring [18]. Sagi et al. described 50 cases, of which 92% had an excellent or good reduction of acetabular fractures. However, the use of lateral window was required in 60% of their cases to achieve reduction of high anterior column fracture and place fixation or insertion of posterior column lag screws, while Anderson et al. reported an 82% anatomic reduction rate [19, 20]. However, the inclusion criteria vary among different studies. Shazar et al., [14] reported that main and statistically significant difference in the achieved reduction rates was in the both-column fracture type for which anatomic reductions were achieved in 54.2% of the patients in the ilioinguinal group and 79.4% of the patients in the modified Stoppa group. They believed that a major benefit in the modified Stoppa approach resulted from the enhanced ability to reduce and fix the posterior column component of the fracture, and the quadrilateral plate component. The ability to add a posterior column buttress plate, underneath the pelvic brim, assists the anatomic reduction of the posterior column and quadrilateral plate obviating medial displacement. The Kocher-Langenbeck approach was added only when the posterior wall component needed to be addressed. The single midline approach allows access to the entire pelvic ring, so that both sided fractures can be approached through a single incision. The anatomic reduction and proper stabilization of fractures allow early beginning of mobilization, rehabilitation and effective functional recovery of the patients. In their series of 41 cases with at least one year follow up, wherein 23 patients were operated using ilioinguinal approach and 18 patients were operated using Stoppa approach, Hammad et al. suggested the advantage of Stoppa approach over and above the ilioinguinal approach for obtaining reduction in both column fractures where a direct buttressing of the quadrilateral plate was required [12]. On the other hand, the ilioinguinal approach, which probably has an upper hand in obtaining reduction in anterior wall fractures with a more transverse fracture line through use of its middle window [12]. Shazar et al., [14] observed absence of a learning curve effect with Stoppa approach as compared to ilioinguinal approach when performed by experienced surgeons. They attributed this to the fact that Stoppa approach is less extensive in a way that it does not require an incision into the inguinal canal. In our analysis, modified stoppa approach is associated with a significantly lower complication rate. Complications such as hernia, thrombosis, neurovascular injuries and hematoma are seen at the rate of approximately 10% in the Ilioinguinal approach. The lymphatic veins with the neurovascular band and the preparation of the funicular structures add an extra risk resulting increased intraoperative time is needed. This may also lead to consequent scar formation or fibrosis on important structures. Most complications of the Ilioinguinal approach are particularly related to the soft tissues of the middle window, while in the newer approach dissection of tissues in this window is avoided, thus potentially minimizing risks of iatrogenic injury to the inguinal canal, femoral nerve and external Iliac vessels. As compared to the classical Ilioinguinal approach, this approach decreases the risk of scar tissue formation and heterotrophic ossification. Operative time may have an effect on the general condition of the patients as well as on the incidence of complications. Using a less traumatic surgical approach with minimal operative time in the reduction and stabilization of pelvic ring and acetabular fractures is very significant in the management of severely polytraumatised patients. The modified Stoppa approach has a significantly lower operating time. This approach, when executed correctly provides clear acetabular access, including access to the pubic body, superior ramus and pubic root, the Ilium above and below the pectineal line, the quadrilateral plate, and the medial aspect of the posterior column, sciatic buttress and anterior sacroiliac joint. This approach can also be used in the surgical treatment of both pelvic ring and acetabular fractures, which is important in management of polytrauma patients following high energy trauma.The limitations of the modified Stoppa approach are that there may be difficulties in reduction and internal fixation of posterior column fractures while impossibility of visualization of the femoral head, labrum, and articular surface of the acetabulum resulting inadequate debridement of the joint. To approach posterior column fractures, Vikmanis et al., [21] used to perform further dissection to the quadrilateral surface; the obturator neurovascular bundle was identified and protected with a retractor. They used individual canalized screws or additional plates for fixation and support of quadrilateral plate. Disadvantages of this approach are risk of peritoneal injury, corona mortis injury and possibility of a postoperative hernia along with adductor weakness. There are several limitations of this meta-analysis study. First, the number of studies included in this analysis is very small and it includes only a single randomised controlled trial. Also, the majority of these studies are of low quality and involve only a small number of patients. Therefore, it is difficult to conclude convincingly from this study about direct comparison between these two different approaches for managing anterior acetabular fractures.

Financial support:

No author had any financial support for study and analysis.

Conflict of Interest:

All of the authors have no conflict of interest.

Compliance with ethical statements:

Ethical committee clearance is not applicable for this manuscript.