The anatomy of Rouviere's sulcus as seen during laparoscopic cholecystectomy

A proposed classification

Abstract

INTRODUCTION: 

Although Rouviere's sulcus is being increasingly mentioned as the first landmark to be seen so as to begin dissection during laparoscopic cholecystectomy to prevent bile duct injuries, the anatomy of the sulcus has not been described in clear and simple terms.

OBJECTIVES: 

To define the detailed anatomy of Rouviere sulcus as seen during laparoscopic surgery in simple terms for the surgeons to refer to and begin their dissection from this, always staying above this sulcus in order to eliminate bile duct injury.

METHODS: 

100 recordings of laparoscopic cholecystectomy were analysed to define the anatomy of the Rouviere's sulcus.

RESULTS: 

Majority of the sulci (71) were seen as a deep sulcus and were labelled as simply the ‘sulcus’. This was further seen to be of two types – open (60) or closed (11). Some of the sulci (23) were small and so narrow and shallow as to be labelled as a ‘slit’. Rarely, the sulcus was found to be fused and represented by a white fusion line (6 cases), and this was simply labelled as a ‘scar’.

CONCLUSIONS: 

The Rouviere's sulcus can now be defined in three simple terms – a deep sulcus, or a slit or a scar. We recommend that as a first step in laparoscopic cholecystectomy, the surgeon must look for this reference point (whether it is in the form of a scar, or a slit or a real sulcus) which will be the plane of the main bile duct, and thus avoid any dissection below this point in order to eliminate any danger to the bile duct during surgery.

INTRODUCTION

With the establishment of laparoscopic cholecystectomy as the ‘gold standard’ method of treatment for symptomatic gallstones, surgeons have had to face an increased risk of injuries to the bile ducts due to the inherent limitations of laparoscopy.

With increasing emphasis on patient safety in recent years, it is being recommended to identify and follow some landmarks which may guide the surgeons from where to begin the dissection by identifying the plane of the common bile duct (CBD) even before the dissection begins.

A common landmark or reference point being increasingly described in recent reports is the Rouviere's sulcus. This sulcus, which was hardly seen and described in the open surgery era, is seen very clearly during laparoscopic cholecystectomy due to the pressure of CO₂ insufflation opening up the sulcus widely and due to the enhanced illumination and image quality of the digital endoscopic cameras.

However, if one considers the anatomy of the Rouviere's sulcus, there are nearly no data about it in the referential anatomical literature, its frequency not well-defined and its morphology not exactly described.

Whatever is previously known about the sulcus comes to us from some seminal studies on liver anatomy by Rouviere,[¹] Gans[²] and Couinaud[³] who just noted that this sulcus was present in the majority of specimens, but the importance of the sulcus was not described. Reynaud et al.[⁴] drew attention to its importance in improving hepatectomy techniques. Hugh et al.[⁵] were the first to draw attention to its importance during laparoscopic cholecystectomy because it accurately indicated the plane of the CBD, this being confirmed by operative cholangiography. Hugh later[⁶] stressed that the sulcus is used as the first landmark from where the dissection should begin during laparoscopic cholecystectomy. Zubair et al.[⁷] described the sulcus as open and closed types depending on whether the right hepatic pedicle was visible in the sulcus or not. Dahmane et al.[⁸] dissected 40 autopsy liver specimens and gave some details regarding the dimensions of the sulcus such as its length and breadth, and what was contained in the floor of the sulcus.

Since no detailed anatomical classification of Rouviere's sulcus exists in the available literature, this study was undertaken to record 100 videos of laparoscopic cholecystectomy procedures in which the Rouviere's sulcus was visible in some form or the other, to describe its variations, to measure its dimensions such as length, width and depth, and then to propose a simple classification of the Rouviere sulcus to which surgeons could refer easily in the future when describing it.

METHODS

A total of 117 consecutive recordings of laparoscopic cholecystectomy had to be studied so as to obtain data for 100 cases in which the Rouviere sulcus was visibly present and then these 100 cases were studied in detail to describe the anatomy of the sulcus. Out of 117 cases, 11 patients had no sulcus, and a further six patients had slit type of sulcus far away from porta hepatis. These latter were excluded from the study as they were not considered to be Rouviere's sulcus.

During surgery, before starting the dissection of the gallbladder, first it was observed if the Rouviere sulcus was present or not.

Then if the sulcus was found to be present, it was noted whether it was seen as a white line (described as a SCAR in our study), or a real sulcus.

If it was a real sulcus, an effort was made to measure its dimensions (length, breadth and depth) with a small length of infant feeding tube marked in cm and introduced through one of the ports [Figure 1].

Figure 1: Measuring the dimensions of the Rouviere's sulcus with a feeding tube marked in centimetre

If the sulcus was too small in its depth and breadth to be measured with the tube in cm, it was described as a SLIT, and only its length was measured.

If the sulcus was deep enough, it was described as a DEEP SULCUS, and all its dimensions were measured in 0.5 cm units and recorded.

Further, a note was made whether this sulcus was open or closed, depending on whether its medial end was open towards the porta hepatis making the portal structures visible (open sulcus), or closed towards the porta hepatis (closed sulcus).

The direction of the sulcus in all of its three forms (scar or slit or deep sulcus) was also recorded as being horizontal or oblique or vertical.

Finally, the floor of the sulcus was observed with a closer view with the camera to find whether the right portal pedicle structures were visible or not.

RESULTS

Out of the 117 cases included in the study, Rouviere sulcus was found to be absent in 11 cases and present in 106 cases. Thus, the sulcus was present in some form or the other in an overwhelming majority of patients (90.6%, 106 out of 117). In a further 6 cases, a slit was present far away from the porta hepatis; these cases were not considered to be Rouviere sulcus in this study.

Out of the 100 cases included in this study in which the sulcus was present in different forms, the Rouviere sulcus was labelled as a SCAR (if the sulcus was seen only as a white scar near the porta hepatis) [Figure 2] or a SLIT (if it was a shallow and narrow sulcus) [Figure 3], or a DEEP SULCUS. The deep sulcus was further categorised as open type [Figure 4] if it was open at its medial end showing porta hepatis clearly, or closed type [Figure 5] if the medial end was closed thus not showing the porta hepatis clearly.

Figure 2: The scar

Figure 3: The slit

Figure 4: The sulcus (open type)

Figure 5: The sulcus (closed type)

The frequency of the various types of Rouviere sulcus

Of a 100 cases, six patients had a scar, 23 had a slit and 71 had a deep sulcus.

Of the deep sulcus cases, 60 (84.5%) had an open type of sulcus, whereas the remaining 11 (15.5%) had a closed type of sulcus.

Thus, the majority of patients had a deep sulcus and out of these, the majority had an open sulcus.

Direction of the scar/slit/deep sulcus

The direction of the sulcus in its various forms was mostly horizontal, sometimes oblique and rarely vertical, as shown in Table 1.

Table 1: The direction of the sulcus

Measurements of the sulcus

In the scar and slit type of sulci, only the length was measured while in the deep sulcus, all three dimensions (length, breadth and depth) were measured.

Length of the scar/slit

Out of the six cases with the scar type of Rouviere sulcus, two had a very long scar, extending from the porta hepatis all the way to the edge of the right lobe of the liver, measuring 16 cm in length. Of the remaining four cases of scar type of Rouviere sulcus, three had a length of 2 cm and one case had a length of 1 cm.

The length of the slit type of Rouviere's sulcus ranged from 1 cm to 4 cm, with the majority of them (18 out of 23, 78%) being 1 cm long [Table 2].

Table 2: The length of scar and slit types of the sulcus

Dimensions of the deep sulcus

The dimensions of the open type of deep sulcus are shown in Table 3.

Table 3: The dimensions of open type of the deep sulcus

The length of the open type of the deep Rouviere's sulcus ranged from 1 cm to 5 cm, and in the majority of such cases, the length of the sulcus was between 2 cm and 3 cm (77%, 47/60).

The breadth of the open type of the deep Rouviere's sulcus ranged from 0.5 cm to 2 cm and in the majority of such cases (76%, 42/60), the breadth of the sulcus was 1 cm.

The depth of the open type of the deep Rouviere's sulcus ranged from 0.5 cm to 2 cm and in the majority of such cases (81.6%, 49/60), the depth of the sulcus was 1 cm.

Thus, the open type of deep sulcus was mostly 2–3 cm long, 1 cm broad and 1 cm deep.

The dimensions of the closed type of deep sulcus are shown in Table 4.

Table 4: The dimensions of closed type of the deep sulcus

The length of the closed type of the deep Rouviere's sulcus ranged from 1 cm to 4 cm, and in the majority of them (54%, 6/11), the length of the sulcus was 2 cm.

The breadth of the closed type of the deep Rouviere's sulcus ranged from 0.5 cm to 1 cm, and in the majority of them (72%, 8/11), the breadth of the sulcus was 1 cm.

The depth of the closed type of the deep Rouviere's sulcus ranged from 0.5 cm to 1 cm, and in the majority of them (72%, 8/11), the depth of the sulcus was 1 cm.

Thus, the closed type of deep sulcus was mostly 2 cm long, 1 cm broad and 1 cm deep.

Mean dimensions of the open and closed types of Rouviere sulcus

The mean length, breadth and depth of open type of Rouviere's sulcus were 2.31 ± 0.3 cm. 1.11 cm ± 0.2 cm and 1.11 cm ± 0.2 cm, respectively.

The mean length, breadth and depth of closed type of Rouviere's sulcus were 2.18 cm ± 0.3 cm, 0.86 cm ± 0.1 cm and 0.86 cm ± 0.1 cm, respectively [Table 5].

Table 5: Mean dimensions of the deep sulcus

The incidence of visible right hepatic pedicle structures in the floor of Rouviere sulcus

Out of the 60 patients with the open type of deep Rouviere's sulcus, the right hepatic pedicle was visible on the floor of the sulcus in a majority of the cases (45 cases out of 60, 75%).

However, out of the 11 patients with the closed type of deep Rouviere sulcus, the right hepatic pedicle was visible in only a minority of cases (one case out of 11, 9%).

Additional features observed

In six patients, the sulcus in the form of a slit was observed to be present far away from the porta hepatis, and these cases were not considered to be Rouviere's sulcus for the purpose of this study which concentrates on highlighting the Rouviere's sulcus as to be the first landmark from where to begin the dissection for laparoscopic cholecystectomy.

In two of the patients included in the study, a closer observation revealed a pulsating vessel in the floor of the Rouviere sulcus.

DISCUSSION

Nomenclature of the sulcus

Descriptions of Rouviere sulcus are very variable and confusing in the literature. Standard anatomy texts do not even mention it. The reason for this may be that the sulcus is hardly visible in the cadavres’ shrivelled livers. We observed this in our own dissection hall in our Anatomy Department.

The original description of the sulcus by Rouviere in 1924 was ‘sillon du processus caude’, translated as ‘grooves or furrows or cracks of the caudate lobe of the liver’. Besides describing a lot of details of the grooves, a significant observation was that the groove was more commonly seen in livers of foetuses and new-borns (81%) than in the livers of adults (52%). Thus, it stands to reason that with advancing age, the groove becomes less noticeable.

Henry Gans in 1955 called the sulcus as ‘incisura dextra’.

Then, in 1957, Couinaud described it as ‘le sillon du processus caude de Rouviere’, thus suggesting the presently used name, the Rouviere sulcus.

Although Reynold et al., in 1991, called the sulcus as ‘incisura dextra of Gans’, all later workers have described it by its justifiably rightful name – the Rouviere's sulcus [Table 6].

Table 6: The nomenclature of the Rouviere's sulcus

The incidence of the sulcus

The Rouviere's sulcus is present in the majority of patients and is nicely visible during laparoscopy, being visible in one form or the other (a sulcus, or a slit, or a scar). In our study, it was visible in 90.6% of cases [Table 7].

Table 7: The incidence of the Rouviere's sulcus

This incidence is the highest of all other studies, possibly because we also included some cases in which it was represented by just a scar. This type of scar was not considered to be a type of Rouviere's sulcus in other studies.

The anatomy of the sulcus

No standard anatomical classification of the sulcus exists in the literature. The term Rouviere's sulcus generally refers to a deep sulcus which is the most common type observed in our study too. However, we observed that in place of the sulcus, sometimes there is a fusion line, which appears like a white line only, and this represents a fused sulcus. We described it as a SCAR type of sulcus. Rouviere himself had described this scar as ‘superficial white border which probably represents the sulcus’. Hugh et al. also mentioned about the fused sulcus and the scar as a line of fusion of the sulcus. Zubair et al. observed that the white line was a useful landmark for the commencement of the dissection, but did not consider this white line as a representation of the sulcus. This scar was seen in 6% of cases in our study.

In some other cases, the sulcus is small, superficial, and narrow and we described it as a SLIT. We felt that this was a convenient and easy term for such shallow type of sulcus. No other previous study has used this term for the Rouviere sulcus. However, Rouviere had mentioned about ‘a fine groove on the inferior surface of the liver’. In our study, this SLIT type of Rouviere's sulcus was seen in 23% of cases.

The more common type of the sulcus, simply called Rouviere's sulcus, refers to a DEEP SULCUS. This can be seen to be closed at both its medial and lateral ends, or it may be open at its medial end, exposing nicely the portal pedicle structures through its open end. Thus, we described the deep sulcus as either closed type or open type depending upon whether the sulcus was closed or open at its medial end. Rouviere had described ‘incomplete grooves’ on the inferior surface of the liver and reported that these were present in 23% of adult livers and 20% of livers of foetuses and children. Gans and Couinaud made no mention about the closed and open types of the sulcus. Hugh et al. recognised the sulcus as being either ‘fully open’ or ‘partially open’. Zubair et al. described the open type of sulcus as a ‘cleft in which the hepatic pedicle was visualised’, and the fused type in which the hepatic pedicle was not visualised. Dahmane et al. defined the open type of sulcus as a cleft in which branches of the right hepatic pedicle were visualised and the sulcus was open throughout its length.

Dimensions of Rouviere sulcus

Rouviere in his original study described the sulcus as being present over ‘one-third of the total width of the right lobe of the liver’ without giving any measurements in cm.

Only two previous studies have measured the sulcus in cm, and our results compare well with them [Table 8].

Table 8: Mean dimensions of the Rouviere's sulcus compared with other authors

Thus in most of the cases, this sulcus is more than 2 cm long, 1 cm broad and 1 cm deep.

In cases of the slit and scar types of the sulcus, only the length was measured. No previous study has measured these less common types of the sulcus since the sulcus has never been described in these terms earlier.

We found the length of the scar to be very variable, being 1 cm in one patient, 2 cm in 3 cases, and in the two remaining cases, the scar was very long, extending from the porta hepatis going all the way up to the edge of the right lobe of liver, and measured as 16 cm.

The length of the slit was 1 cm in the majority of cases, while in some cases, it varied from 2 to 4 cm.

The direction of Rouviere sulcus

The direction of the sulcus is mostly horizontal, less commonly oblique, and rarely vertical as observed in our study. Rouviere had commented that in 25% of adult livers, the groove was directed ‘obliquely to the right and slightly forward’. Dahmane et al. noted that in 97% the direction of the sulcus was oblique to the anterior/inferior/external edge of the liver, and horizontal in 3%.

The floor of the sulcus

What is contained in the floor of the sulcus has been well described by Dahmane et al. in their autopsy liver specimens, when they noted that mostly it is the right portal pedicle that was present on the floor, while less commonly the floor of sulcus may contain a branch of the anterior sectional pedicle or even a vein of the segment 6. In our study, it was noted that with good illumination, structures of the portal pedicle were often visible on the floor of the sulcus, more commonly if the sulcus was open at its medial end and less commonly if the sulcus was closed at its medial end. With closer vision, we also observed a pulsating vessel on the floor of the sulcus in two cases.

Thus, this study has given comprehensive details of the laparoscopic anatomy of Rouviere's sulcus, and also added two easy terms – the scar and the slit – in which forms the sulcus may sometimes be seen.

The clinical relevance of the study would be for all surgeons to first of all look for the sulcus in one of its forms we described (a scar, or a slit or a deep sulcus), and then only begin dissecting because this sulcus represents the plane of the CBD and if one does not stray below the level of the sulcus, the possibility of bile duct injury could be eliminated.

CONCLUSIONS

The Rouviere's sulcus is most commonly visible as a deep groove which is open at its medial end (OPEN SULCUS) thus clearly showing the right hepatic portal pedicle as it exits the liver hilum. Thus, it is a very useful landmark for surgeons to begin dissection during laparoscopic cholecystectomy. Less commonly, it is seen to be closed at its medial end (CLOSED SULCUS). Sometimes, it is a narrow and shallow sulcus (SLIT). Rarely, it is fused and represented by a white line of fusion (SCAR).

We propose this simple classification of the anatomy of the Rouviere's sulcus (a scar, a slit or a sulcus - open or closed) for surgeons to follow easily as a reference point to begin dissection during laparoscopic cholecystectomy. We recommend that as a first step in laparoscopic cholecystectomy, the surgeon must look for this reference point (whether it is in the form of a scar, or a slit or a real sulcus) which will be the plane of main bile duct, and thus avoid any dissection below this point in order to eliminate any danger to the bile duct during surgery.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.