Title: Subinguinal approach to pelvis and acetabulum
Author(s): Hamid Reza Seyyed Hosseinzadeh MD, Farivar Bagheri MD, Mehrnoush Hassas Yeganeh MD*
Affiliattion(s): Shahid Beheshti University of Medical Sciences, Tehran, Iran
* Corresponding Author
Vol 1, Num 2, October 2014
The ilioinguinal approach is the approach of choice in the fractures of anterior part of pelvis especially in the region of pubic ramus, but there are some technical difficulties which may result in inguinal herniation or inguinal ligament injury and it provides a limited exposure. Therefore, it is not suitable in some complex fractures. In 2008, a modified ilioinguinal approach was introduced in our department which provided a complete view of the inside and outside of the pelvis.
The approach involves retroperitoneal access below the inguinal ligament to preserve the integrity of the inguinal canal and allows exposure of anterior and medial wall fractures as well as the anterior hip capsule. Despite the dimensions of the procedure, closure is anatomical because repair of the inguinal canal floor is not required. We report again the use of this approach in 45 patients with transverse and T-type fractures of the acetabulum, Tile C1 and C2 pelvic fractures, malunion of the pelvis, acetabular dysplasia and pelvic tumor resection. The approach is recommended in complex cases of acetabular surgery (including obese or muscular patients) and complicated or old fractures in which a better exposure is required. It is useful in visualization of the anterior wall and labrum and intra articular structures, and in viewing the internal anatomy of the pelvis and acetabulum. It proved to be suitable for periacetabular osteotomy.
Keywords: Ilioinguinal approach, Subinguinal, Retroperitoneal, Acetabular fracture, Anterior wall
The classic ilioinguinal approach is suitable for the anterior parts of the pelvis and acetabulum.(1) It was first described by Letournel and indications were defined and enlarged afterwards.(1) Nowadays the approach is only used for fractures of the anterior wall, anterior column and for anterior column-posterior hemitransverse fractures of the acetabulum.(2) It can be applied along with a posterior approach for transverse, T-type and double-column fractures of the acetabulum.(3)
It is the approach of choice for fractures of the anterior part of the pelvis especially in the region of pubic ramus.(3,4) It is associated with some technical difficulties. It involves exploration of the inguinal canal floor which (without complete repair) may result in inguinal herniation.(5)
Furthermore, the inguinal ligament may be injured. Preservation of the ligament impedes distal visualisation, and observation of the acetabular anterior wall and the joint capsule is impossible.(5) Thus, this approach is not suitable when there are acetabular or pelvic fractures with femoral head impaction, intra-articular incarcerated fragments or anterior labral injuries.(5,6) Approaches that provide proper visualization of the intraarticular space leave the intrapelvic side of the acetabulum and quadrilateral plate out of reach.(6,7)
It is notable that fixation of acetabular fractures via the ilioinguinal approach and arthrotomy are not possible at the same time. Therefore, there is a need for a single approach that provides proper access to the intra-pelvic parts of acetabulum, joint capsule and acetabular joint space simultaneously. In 2008, Farid YR introduced a modified ilioinguinal approach which was used originally in pelvic tumor surgery. It demonstrated a complete view of the inside and outside of the pelvis.(5)
We report our experience with this technique. This is a report of extension of the indications of an approach which was reported previously. At first we used this method for acetabular fractures, but because of the excellent exposure obtained we extended it to pelvic fractures, pelvic nounions, periacetabular osteotomies and pelvic tumor resection.
This approach starts with a transverse curved incision 1 cm above the symphysis pubis and continues with an upward concavity to just below the anterior superior iliac spine (ASIS), at this point the curvature changes downward as a slight concavity and continues posteriorly parallel to the iliac crest and 1 cm below it according to the field of view required. The cutaneous incision of this approach and the incision of the deep tissues are distal to the classic ilioinguinal approach.
After dissecting the subcutaneous tissues, the white and dense fibers of inguinal ligament and its border with thin fascia of the thigh as well as the external inguinal ring and its components can be distinguished. In contrast to the classic ilioinguinal approach which involves dissection of the canal floor, in this approach the distal border of inguinal ligament is separated from the thigh fascia. Deep to this thigh fascia, there are three compartments in including the iliopsoas muscle and femoral nerve, femoral artery and vein and finally the spermatic cord in men and round ligament of uterus in women.
The attachment of the inguinal ligament to the ASIS is preserved, while the origin of sartorius muscle to the ASIS is released. The origins of the iliopsoas muscle and abductors of the hip are released from the iliac crest. After drilling a 2.7 mm hole in the ASIS for the later screw fixation, the ASIS and part of iliac crest (up to the iliac tuberosity) with the attached inguinal ligament are osteotomized. This osteotomized bone along with the attached inguinal ligament are retracted superomedially. Similar to the classic approach, the spaces between the compartments should be clearly explored.
There are 3 windows to the pelvic brim. From lateral to medial, the first window is lateral to iliopsoas muscle, the second one is between iliopsoas muscle and the femoral artery and the third is between femoral vein and spermatic cord in men or round ligament in women. At this point the rectus abdominis muscle is located medial to the spermatic cord in men or round ligament of the uterus in women and is attached to the superior border of symphysis pubis. For visualizing the superior border of the symphysis pubis and inserting a plate over it, the anterior part of rectus abdominis connections to the symphysis are released. On the lateral side, the iliacus muscle is detached subperiosteally and the pelvic brim becomes distinguishable superiorly. With further blunt dissection the dimension of these 3 windows is enlarged and better access to the retropritoneal region is obtained. The medial portion of conjoint tendon can also be cut.
Since the ASIS osteotomy releases the inguinal ligament, the field of view in the middle window (between iliopsoas muscle and the femoral artery) is more than in the classic approach and visualization of more internal areas of the pelvis and acetabulum is possible. By retracting the sartorius muscle distally, it is possible to view the anterior wall and labrum of the acetabulum, and then by releasing the attachments of the straight head of rectus femoris muscle from the capsule, complete visualization of the joint capsule is possible and it can be opened for assessment of the interior of joint. This is not possible with the classic ilioinguinal approach (Figure 1).
In contrast to the classic ilioinguinal approach in which wound repair at the end of operation is very precise and delicate and the floor and roof of the inguinal canal must be repaired meticulously, in this approach, the osteotomized fragment of ASIS is fixed with two screws, then the lower edge of inguinal ligament is sutured to the thigh fascia. The detached muscles from iliac crest should be connected to each other and to the crest. The structures that were released in the medial side of the wound, such as the conjoint tendon or rectus abdominis muscle are reattached to their attachment sites. The sartorius muscle is reconnected to ASIS. Finally, the subcutaneous layer and the skin are repaired.
This approach was performed on 45 patients including 23 fresh pelvic and acetabular fractures, 1 pelvic malunion, 18 acetabular dysplasia cases which underwent Ganz osteotomy and 2 pelvic tumors undergoing tumor resection. For all anterior column and both-column acetabular fractures which needed an anterior approach, this Subinguinal approach provided enough exposure to reduce and fix the fracture.
In patients with pelvic fracture, whenever we needed an open approach, we used this Subinguinal approach with good exposure for fracture reduction and fixation. In all cases with acetabular dysplasia, we exposed the acetabulum with this approach and were able to see both the inside the pelvis and inside the hip joint.
The classic ilioinguinal approach is an excellent approach in the treatment of acetabular and pelvic fractures. It has a low incidence of complications such as infection, heterotopic ossification and vascular and nerve injuries.(1) Despite providing an appropriate view of the pelvic brim and anterior column of the acetabulum, visualizing the anterior wall and labrum of the acetabulum, anterior capsule and the inside of the acetabulum is impossible because of the inguinal ligament in the distal portion of the operation field.(6)
On the other hand, as the inguinal ligament prevents retracting the edges of the windows between the neurovascular compartments, the dimension of these windows remain small and do not provide proper visualization of the medial wall of the acetabulum.(5) In order to improve this approach some changes have been proposed previously. They limited the approach to one window for to decrease surgical trauma (especially to avoid vascular injuries) or widened it by making a T-shaped extension to increase the width of the field. Each of these changes addressed only one of the technical difficulties of the ilioinguinal approach.(5,6,8)
Our approach resolves several technical difficulties and limitations of the ilioinguinal approach. First, ASIS osteotomy and elevation of the inguinal ligament, eliminates limitations caused by the presence of this ligament in the distal part of incision including lack of visibility of the anterior acetabular wall and joint space and inadequate retraction of vessels in order to observe the medial part of acetabulum and pelvis.(5) Thus, a better view of the joint and internal wall of the acetabulum without increasing the incision size is provided. This means that there is no need to open the inguinal canal floor, resulting in minimal abdominal wall weakness and reduced risk of inguinal herniation. We didn't encountered any nonunions of the ASIS osteotomy. However, the treatment of ASIS nonunion is probably easier than the repair of inguinal canal injuries.
As the inguinal canal remains intact in this approach, it could be a very safe method in the patients with history of inguinal hernia repair with adhesions in the area.(5) In the subinguinal approach, each window is a long rectangle which extends to the articular capsule. Therefore there is an excellent view of acetabulum and pelvis. With this approach it is possible to gain access to the anterior labrum and interior of the joint and address pathology appropriately.(5)
Furthermore, the internal wall of the pelvis can be seen well through the middle window and it is possible to fix and reduce old and complex fractures in this region.(5) Due to the inter-muscular (instead of intra-muscular) dissection; there is less bleeding. The wound repair in this approach is easier and anatomical. Trauma to the external femoral vessels and heterotopic ossification (as a result of manipulation of the hip abductor muscles) are two potential shortcomings of this approach.(5) Moreover, the approach has a learning curve before it can be performed accurately.
The approach described is recommended in complex acetabular surgery (including obese or muscular patients) and complicated or old fractures in which a better exposure is required. In addition to allowing visualization of the internal parts of the pelvis and acetabulum it affords access to the anterior wall and labrum and intra articular compartment. It provides simultaneous visualization of the joint, external part of the ilium and internal parts of acetabulum. Finally, we believe it has proved to be a suitable approach for periacetabular osteotomy.
Hamid Reza Seyyed Hosseinzadeh MD Orthopaedic surgeon, Associate professor, Shahid Beheshti Medical Univerity, Tehran, Iran email@example.com
Farivar Bagheri MD Orthopaedic surgeon, Shahrud, Iran firstname.lastname@example.org
Mehrnoush Hassas Yeganeh MD Assistant professor, Paediatric rheumatologist, Shahid Beheshti Medical University, Tehran, Iran Corresponding Author email@example.com
Acknowledgements: None declared.
Financial disclosure: None declared.
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