The clinical anatomy of laparoscopic inguinal hernia repair

Laparoscopic approaches for abdominal surgery are being used with increasing frequency. Their advantages are sometimes negated by the disturbing incidence of postoperative sequelae. In the case of inguinal hernia repair, these are often the result of failing to understand that the anatomy of the anterior approach to the abdominal wall cannot necessarily be directly applied to laparoscopy. The inguinal ligament, easily identified in an anterior approach, is only seen laparoscopically after removal of the iliopubic tract, a key structure which lies in the plane of the original defect of most groin hernias. Thus, an understanding of the incompletely trilaminar anterior abdominal wall, including the iliopubic tract, is the foundation for effective inguinal hernia repair using any approach (anterior or posterior) or technique (sutures, mesh or staples). Laparoscopic inguinal hernia repair has produced an increase in the frequency of debilitating neuropathies, most notably of the lateral femoral cutaneous nerve (LFCN). This is directly related to the variable intrapelvic course of this nerve or its branches. In more than 13% of the 114 pelves we examined, the LFCN was within 0.5 cm of the iliopubic tract or in the vertical plane of the anterior superior iliac spine, key lateral landmarks and anchoring sites for mesh in laparoscopic hernia repairs. Medial landmarks also have variable features. These data indicate that the identity of anatomical landmarks and the variability of other structures will continue to be important in the successful development of new laparoscopic techniques.

Putting a finger on the deep inguinal ring

The clinical distinction between direct and indirect inguinal hernias is often made by determining whether digital pressure over the deep inguinal ring is able to control the hernia. In 25 consecutive patients having inguinal hernia operations, the positions of the mid-inguinal point and the mid-point of the inguinal ligament were determined pre-operatively and compared with the position of the deep inguinal ring measured at operation. Neither the mid-inguinal point nor the mid-point of the inguinal ligament correctly predicted the position of the deep inguinal ring (the mean position of the deep inguinal ring was found to be 0.52 cm lateral to the mid-inguinal point and 0.46 cm medial to the mid-point of the inguinal ligament). If the position of the deep inguinal ring cannot be accurately determined using fixed landmarks, it is unlikely that direct and indirect inguinal hernias can be distinguished by clinical examination.

The secondary internal ring: applications to surgery of the inguinal canal

PURPOSE

In 1975 the clinical importance of the preperitoneal fascial or secondary internal ring was noted based on procedures performed through the suprainguinal preperitoneal approach. The importance of knowledge of the secondary internal ring in the performance of inguinal hernia repairs, orchiopexies and operations for impalpable testes through the inguinal canal is shown, along with a description of the anatomy of the internal ring and subjacent retroperitoneal connective tissue.

MATERIALS AND METHODS

More than 250 consecutive inguinal canal dissections were performed during surgery for inguinal hernia repair, orchiopexy or impalpable testes by a single surgeon using 3.5x magnification.

RESULTS

The intraoperative dissections clearly showed the existence of a secondary internal ring, which when opened provided wide access to the retroperitoneal space containing the internal spermatic vessels and vas deferens.

CONCLUSIONS

Knowledge of the anatomy of the secondary internal ring is an adjunct to the performance of operations through the inguinal canal.

Influence of inguinal node anatomy on radiation therapy techniques

A 1992 GOG (Gynecologic Oncology Group) study suggested that groin irradiation does not control microscopic inguinal node metastases as well as does surgical dissection. That trial has come under some scrutiny, as possible deficiencies in the radiation regimen used might have influenced results. The study received criticism for assigning a prescription point [Rx@3 cm below anterior skin surface] to patients which may not have given adequate coverage to the inguinal nodes. The inguinal node depths of 31 patients with cervical, vaginal, or vulvar malignancies were measured from their planning CT scans and then compared to depth of the prescription point designated by the radiation therapists in the aforementioned study. Twenty-four of eighty-one viable superficial inguinal node depth measurements were greater than 3 cm, and all of eighty-four deep inguinal node measurements were outside the three centimeter range. The results of this project would indicate that the depths of patients' inguinal nodes vary enough to justify alterations in some present external beam radiation therapy techniques. Indiscriminate prescription points will no longer suffice if groin radiation is to be effective, and treatment planning must utilize imaging studies to devise radiation regimens that provide optimal dose to the superficial and deep inguinal nodes.

Femoral pulse as a guide to the mechanical axis in total knee arthroplasty

The anatomic relationship of the center of the femoral head to the femoral artery was studied in 140 hips in 70 patients. The coronal plane distance between the femoral artery 2.5 cm below the inguinal ligament and the center of the femoral head was measured on pelvic arteriograms. The femoral artery was found an average of 7.7 +/- 5 mm medial (range, -3-22 mm) to the center of the femoral head. The femoral artery was within 15 mm of the center of the femoral head in 93% of cases reviewed. A 76-cm theoretical mechanical axis was used in estimating clinical angular changes in the axis for a given coronal plane difference. By use of this model, the range of variability translates into a maximum change in the mechanical axis of 1.66 degrees and up to only 1.2 degrees in 95% of the cases reviewed. A marker placed just lateral to the palpable femoral pulse approximately 2 to 3 cm below the inguinal ligament is suitable as a guide to locate the center of the femoral head when determining the mechanical axis during total knee arthroplasty.

Decision-making in surgery: how should an inguinal hernia be repaired?

The objective in inguinal hernia surgery is to provide a tension free repair wherever there is a posterior inguinal canal weakness. Mesh repair is at present undergoing a resurgence in popularity as the method of choice, inserted either at open surgery or laparoscopically.

Femoral nerve "sheath" for inguinal paravascular lumbar plexus block is not found in human cadavers

STUDY OBJECTIVE

To determine if a femoral nerve sheath capable of conveying local anesthetic to the lumbar plexus and the obturator nerve exists in human cadavers.

DESIGN

Injection of methylene blue dye into the femoral nerves of human cadavers followed by dissection and observation of dye distribution.

SETTING

University medical center pathology department autopsy room.

PATIENTS

Six fresh adult cadavers about to undergo postmortem examination.

INTERVENTIONS

Both femoral nerves of six fresh cadavers were injected with either 20 ml or 40 ml of dye. The abdomen was opened and distribution of the dye was observed.

MEASUREMENTS AND MAIN RESULTS

In all of the cadavers studied there was no evidence of a femoral nerve sheath capable of conveying methylene blue dye to the lumbar plexus. Both 20 ml and 40 ml of dye injected into the femoral nerve failed to reach the lumbar plexus or the obturator nerve. When 40 ml of dye was injected it always stained the femoral nerves, it usually stained the lateral femoral cutaneous nerves, but it never stained the obturator nerves.

CONCLUSIONS

A femoral nerve sheath capable of conveying a solution to the cadaver lumbar plexus does not exist in human cadavers. Dye injected into the cadaver femoral nerve does not reach either the lumbar plexus or the obturator nerve. When 40 ml of methylene blue dye is injected into the cadaver femoral nerve, some dye usually diffuses under the iliacus muscle fascia to the lateral femoral cutaneous nerve. This study indicates that in patients the "3-in-1 block" always blocks the femoral nerve, it usually blocks the lateral femoral cutaneous nerve, but it probably does not block the lumbar plexus or the obturator nerve.

["Canadian" hernioplasty with embrication. Anatomy, surgical technic, and personal experience]

Among the numerous operations proposed for the treatment of inguinal hernia, the authors utilised Shouldice's method of hernioplasty in over 400 cases of non-recurrent hernia. After drawing attention to a few anatomical type specifications regarding the inguinal canal structures, the "Canadian" surgical technique is described in detail. The authors analyse the various methods of hernioplasty now used and conclude that Shouldice's method should be considered elective in the treatment of primary direct inguinal hernias and voluminous indirect hernias in adults.

Crucial anatomic lessons for laparoscopic herniorrhaphy

Laparoscopic herniorrhaphy is generally performed using a transabdominal approach, an approach to hernia repair that is unfamiliar to most general surgeons. There is sufficient published anecdotal experience to indicate that the relationships of structures near the internal ring are not generally known and that this may predispose to their injury. There is considerable variability of nerves that pass through, or deep to, the iliopubic tract lateral to the internal inguinal ring, making it potentially hazardous to place staples or sutures in this region. Medially, the surgeon must be conscious of the possible presence of an aberrant obturator artery or vein and unexpected iliopubic vessels and take appropriate precautions to avoid unexpected sources of hemorrhage. The human cadaver, especially in the unfixed state, can be an ideal model to learn the surgical anatomy for laparoscopic hernia repair and to avoid neurovascular injuries.

Dissection of the anterior abdominal wall and the deep inguinal region from a laparoscopic perspective

The usual dissection by medical students of the anterior abdominal wall and the inguinal region proceeds from superficial to deep; special emphasis is placed on the sheath of the rectus abdominis muscle and lateral muscular layers. We suggest an alternate approach to dissection of this region that has the following advantages: (1) sparing of delicate deep structures not often fully appreciated by students; (2) provision of an opportunity to visualize the region from a laparoscopic surgeon's vantage point; (3) considerably reduced time spent dissecting and identifying structures and relationships, especially peritoneal reflections important in laparoscopic procedures. Our dissection begins with bilateral subcostal incisions through the entire thickness of the anterior abdominal wall and peritoneum, which extend laterally and inferiorly to the level of the anterior superior iliac spines, thereby forming a large, inverted, U-shaped flap. This flap is reflected inferiorly, allowing abdominal viscera to be dissected, and ultimately removed en bloc. The flap is then drawn cranially and stretched somewhat to approximate its position when the abdomen is inflated with CO2 during laparoscopic procedures. Major landmarks, including the deep inguinal ring, are noted and the flap is again reflected inferiorly for dissection beginning with the peritoneum and transversalis fascia. This method of dissecting the anterior abdominal wall and inguinal region results in more facile and timely identification of both superficial and deep structures of the anterior abdominal wall and inguinal region, and provides a clinically relevant demonstration of anatomy from a laparoscopic perspective.

Normal and abnormal pelviscopic anatomy at the internal inguinal ring in boys and the vasal triangle

OBJECTIVES

We sought to explain and define normal and abnormal laparoscopic pelvic anatomy, which has only recently become the target of much attention.

METHODS

The embryology, normal anatomic landmarks, and abnormal findings of the male pelvis, as discerned from more than 350 laparoscopic investigations in boys, were analyzed.

RESULTS

The medial umbilical ligament, the wishbone at the internal inguinal ring, the transverse vesical fold, and the vasal triangle are principal laparoscopic landmarks of the male pelvis. Deficient spermatic vessels, abnormal gonadal locations, patent processus vaginalis, single medial umbilical ligament, and transverse testicular ectopia were the abnormal findings.

CONCLUSIONS

Laparoscopic familiarity with the male pelvis permits safe and efficient diagnostic and therapeutic navigation in this new surgical arena.

Surgical anatomy of the interior inguinal region. Consequences for laparoscopic hernia repair

Exploration and placement of staplers in the internal inguinal region during laparoscopic hernia repair may sever blood vessels or nerves. Lesions of specific structures may be associated with such complications as hematomas and impaired sensibility in defined areas. Therefore, the course and topography of blood vessels and nerves in the preperitoneal tissue in this region were studied. Six human preserved male cadavers were dissected. Unsafe areas for stapling were described. An adjustment of the technique of laparoscopic hernia repair to circumvent these complications is proposed.

Embryologic and anatomic basis of inguinal herniorrhaphy

The embryology and surgical anatomy of the inguinal area is presented with emphasis on embryologic and anatomic entities related to surgery. We have presented the factors, such as patent processus vaginalis and defective posterior wall of the inguinal canal, that may be responsible for the genesis of congenital inguinofemoral herniation. These, together with impaired collagen synthesis and trauma, are responsible for the formation of the acquired inguinofemoral hernia. Still, we do not have all the answers for an ideal repair. Despite the latest successes in repair, we, to paraphrase Ritsos, are awaiting the triumphant return of Theseus.

Perinatal development of gubernacular cones in rats and rabbits: effect of exposure to anti-androgens

In male rats gubernacular cones develop during the latter half of prenatal life. Inversion of these papilla-like organs after birth is the first step to postnatal growth of the muscular cremaster sacs. The factors regulating prenatal growth and differentiation or postnatal inversion of these gubernacular cones are unknown. The lack of a detailed and unequivocal description of the normal gubernacular cone growth is judged at least partially responsible for this ignorance. The present study therefore describes the normal development of the gubernacular cones in male and female rats from day 14 of fetal life. Androgens are hypothesized to control male gubernacular cone development but recent evidence throws doubt upon this proposal. Therefore, the second part of this study describes perinatal development of gubernacular cones in male rat foetuses exposed to the anti-androgen flutamide from day 10 after conception. Quantitatively normal growth occurred prior to birth, indicating no role of androgen in this process. Excessive growth in length was noticed during the neonatal period together with delay of gubernacular cone inversion. These developmental alterations did not represent direct anti-androgen-induced modifications of gubernacular cones development as the alterations were not observed in flutamide-exposed neonatally castrated animals. Failure of androgens to affect directly perinatal gubernacular cone growth could represent a rat-specific feature. Fetal rabbits show the development of similar structures during the second half of fetal life.(ABSTRACT TRUNCATED AT 250 WORDS)

The space of Bogros and the deep inguinal venous circulation

The ideal reconstruction of the floor of the inguinal canal during a herniorrhaphy implies a good anatomic dissection and exposure. This cannot be accomplished without entering the subinguinal space of Bogros. This space presents a venous circulation that has not been entirely identified in the past. As an aid to accomplishing a safe and bloodless dissection, these vessels have been described--the deep inferior epigastric vein, the iliopubic vein, the rectusial vein, the retropubic vein and the communicating rectusio-epigastric vein, and their relationship into a venous circle. The need to map these vessels is becoming more crucial as surgeons choose varied approaches to the space of Bogros and insert synthetic mesh that requires anchoring.

Cooper's posterior lamina of transversalis fascia

The original description of the transversalis fascia and the internal inguinal ring by Astley Cooper in 1804 is recounted along with the immediate recognition of its importance by other surgical anatomists. The description he made in 1807 of two laminae has been essentially ignored or denied. The deep posterior lamina has been confused with a membranous condensation in the preperitoneal fascia. However, Lytle and Fowler reported a secondary or deeper internal ring and Mackay described the inferior epigastric artery perforating the transversalis fascia at its origin and then coursing cephalad on it to enter the rectus sheath anterior to the arcuate line. My experience with preperitoneal exposure of groin herniae, from the anterior and posterior approach, has demonstrated a posterior lamina deep to the epigastric vasculature attached to the pubic ramus. Repair of inguinal herniae should begin in the preperitoneal layer internal to Astley Cooper's bilaminar transversalis fascia and the epigastric vessels. This will ensure ligation of any peritoneal sac within the iliac fossae, as recommended by Bassini, or internal to the false neck, as described by Henry. This is the avascular, fissile, envelope in which Stoppa has so successfully placed prostheses.

Testicular artery ramification within the inguinal canal

Testicular arterial anatomy has been well studied because of its important role in testicular physiology and testicular surgery. Contrary to classical anatomical descriptions, we have observed that often more than 1 branch of the internal spermatic artery is present at the level of the proximal inguinal canal. Many surgeons who perform varicocelectomy assume that only 1 artery is present at this level and ligate all other vascular structures once an artery has been identified. We determine the frequency and number of internal spermatic arteries present within the spermatic cord in the proximal inguinal canal. The number of internal spermatic arteries present at this level was studied in 15 spermatic cords of 12 patients undergoing varicocelectomy using loupe magnification and intraoperative Doppler ultrasound. The number of arteries ranged from 1 to 3, with a mean of 2 arteries. Histological studies of the same area of 17 spermatic cords obtained from cadavers revealed a mean of 2.4 arteries (range 1 to 3). Knowledge of the frequent early branching of the internal spermatic artery will prevent inadvertent interruption of testicular arterial blood flow during operations performed upon the spermatic cord within the inguinal canal.

Topography of the major superficial lymph nodes and their efferent lymph pathways in the koala (Phascolarctos cinereus)

The koala has an inguinoaxillary lymph trunk on either side of the ventral midline, and this carries efferent lymph from the superficial inguinal lymph node directly to the deep axillary lymph node. The superficial lymph nodes are large and soft compared with those of the domestic species, and each lymph centre usually contains only one or two large lymph nodes. Koalas have a rostral mandibular lymph node which has not been described in other species, but lack popliteal and subiliac lymph nodes. The superficial lymph nodes which are readily palpable in the live koala are the facial, rostral mandibular, mandibular, superficial axillary and superficial inguinal. All superficial lymph pathways terminate at the confluence of the common jugular and subclavian veins.

Fine structure of lymph pathways in nodes from the superficial inguinal lymph centre in the pig

In the pig lymph node most lymph passes from afferent lymphatics to trabecular sinuses in centrally located dense nodular tissue. The lining of these sinuses is continuous adjacent to the trabecula but it is interrupted by numerous gaps adjacent to the parenchyma. Where the trabeculae end, their associated sinuses are continuous with the many interstitial spaces, up to 10 microns across, in the diffuse tissue. Lymph percolates through these spaces and is directly exposed to large numbers of macrophages with elaborate cytoplasmic veils and to reticular fibres which could be involved in antigen retention. Parts of the diffuse tissue are arranged into sinuses and cords in a manner similar to the medullary tissue in other species and a subcapsular sinus is also present over the diffuse tissue. There are gaps in the lining of these sinuses through which they communicate with the interstices of the parenchyma. Lymph flows from the sinuses in the diffuse tissue into efferent lymph vessels; these are usually in the capsule or along the plane of fusion of adjacent node anlagen.

Surgical anatomy of the inguinal area

The anatomy of the inguinal region is enigmatic and confusing. Among the many structures involved in hernial repair are the iliopubic tract, the transversus abdominis aponeurosis and the transversalis fascia, the transversalis crura and sling, and the inguinal canal. There is still much disagreement among surgeons and anatomists about the existence, structure, and function of these anatomic entities.

The inguinal region: anatomic differences in men and women with reference to hernia formation

Fifty inguinal regions were dissected in anatomic human adult specimens, of which 26 were males and 24 females. The comparison of anatomic variations in both sexes showed that the distance between the public tubercle and the internal ring was larger, and the rectus muscle significantly wider in females. The diameter of the internal ring was larger in males, however, with significant variability. No differences were found regarding the presence or absence of the conjoint tendon. The anatomic variations may explain the sex differences in hernia formation.

The relationship between the common femoral artery, the inguinal crease, and the inguinal ligament: a guide to accurate angiographic puncture

The variability of the extraperitoneal puncture space between the inguinal ligament and the inguinal crease was evaluated in 100 patients. The distance between the inguinal crease and the inguinal ligament varied from 0 to 11 cm (average 6.7 cm +/- 1.9 SD), the average value for women (7.5 cm +/- 1.9 SD) being significantly greater than that for men (6.3 cm +/- 1.9 SD, p = 0.0128). The bifurcation of the common femoral artery was found below the inguinal crease in 20%, at the same level in 3.5%, and above it in 76.5% of cases. Consideration of these results will help avoid intraperitoneal puncture and improve the rate of successful antegrade puncture of the femoral artery.

[Mechanism of hernia of the groin]

Utilitarian aspects of hernia pathogenicity are envisaged to assist comprehension of surgical gestures, the choice of effective techniques and the abandon of those which are not and may be of medicolegal interest: all inguinal hernias are due to parietal weakness. Anatomical factors are studied based on data from dissection, from in front backwards and then from behind forwards, from which certain major notions are drawn: that of role of transverse fascia in imperviousness to intra-abdominal pressure; that of uniqueness of inguinal hernias, all of which cross the transverse fascia in the region of the regional osteomuscular framework; that of the necessary degradation of musculofascial plane for a hernia to develop, with as a corollary the need for inguinal imperviousness at the transverse fascia level to be restored. Factors may be present that increase the "natural weakness" of the groin: anatomical variations affecting inguinal triangle; biological disorders affecting inguinal structures (aponeurotic and fascial senescence, collagen diseases, musculo-tendino-aponeurotic dystrophy). A breakdown in mechanisms of protection against increased intra-abdominal pressure promoted a summary of features defining intra-abdominal pressure under physiologic conditions and classical herniogenic circumstances. A summary of pathogenic mechanisms of inguinal hernia is presented while emphasizing the two principal theories: the saccular theory and that of musculo-fascial weakness, with their consequences for choice of therapies to be opposed to the polymorphism of hernial lesions.