Three-dimensional geometrical models of the inguinal region. Towards a new stereology

In this work we studied the inguinal-abdominal region and the inguinal canal using three-dimensional geometrical models. We built the models through computer aided geometric modeling techniques on the basis of observations during real dissections, operations and diagnostic medical imaging. The obtained models show in a complete modular synthesis and with a schematic iconology the structural organization of the anatomical districts in a logic sequence of layers and topographic and spatial relationships among its components. The models represent an amazing support to anatomy and clinical anatomy for teaching and research purposes on organogenesis, surgery and diagnosis.

Surgical treatment of inguinal herniae in children

The aim of this paper was to assess if there is a standard technique for the repair of inguinal herniae in children and to establish if the inguinal canal should be routinely opened during this procedure in different age groups. A postal survey was conducted by sending questionnaires to 264 consultant surgeons who were surgical tutors or advisors to the Royal College of Surgeons of England. Information was sought using a multiple-choice tick-box questionnaire. The surgical techniques of surgeons working in specialist units were compared with those working in general units, and comparisons were also drawn between surgeons performing more operations than those doing only a few and also if the technique varied with the age of the patient. The response rate was 69%. Only 23% working in specialist units and 8% from general units performed more than 30 herniotomies per year. Overall, 15% of surgeons always performed the operation through the inguinal canal, 56% performed it superficial to the external ring, and 29% tended to do both. In children under the age of 2 years, most surgeons performed the operation superficial to the external ring, although a higher proportion of surgeons at specialist units opened the inguinal canal routinely. In the older age groups, the tendency to open the inguinal canal and/or divide the external ring was greater. However, surgeons at specialist paediatric units and those performing more than 30 herniotomies in a year were more likely to open the inguinal canal without dividing the external ring in all age groups. There was quite obviously no standard surgical technique for inguinal herniotomy in children in this survey, and there are only trends.

A novel incision for groin pathologies in children: the low inguinal groove approach

BACKGROUND

The traditional approach to pediatric inguinal pathologies has been the suprapubic transverse inguinal incision. Alternative incisions for better cosmetic results may be considered.

MATERIALS AND METHODS

The recently defined "low inguinal groove incision" was used in a consecutive series of 483 children having indirect groin hernias, hydroceles, and palpable undescended testes, etc. The neonates, infants, and children were operated on as elective day surgery cases.

RESULTS

All children ended with excellent cosmetic and functional results. There were no complications or morbidity apart from a recurrence of an inguinal hernia in a 7 year-old boy. In addition to the series of girls reported earlier, this novel surgical incision has further been employed in boys with excellent results.

The development of the gubernaculum and inguinal closure in the marsupial Macropus eugenii

This study reports the developmental anatomy of testicular descent and inguinal closure of the tammar wallaby (Macropus eugenii) from birth to maturity. In females the ovary migrated caudally between days 10 and 20 after birth. The gubernaculum differentiates into the round ligament in the abdomen and extra-abdominally as the ilio-marsupialis muscle of the mammary glands. In males the testes migrated to the internal inguinal ring by day 20 post partum (pp), coinciding with the enlargement of the gubernaculum, and from the internal inguinal ring to the scrotum between days 20 and 65 pp. During descent there was an increase in the hyaluronic acid concentration in cells of the gubernaculum and scrotum. Development of the cremaster muscle began by day 10 pp on the periphery of the gubernaculum and its basic structure was completed by day 60 pp. After descent the inguinal canal closed between days 50 and 60 pp, but a small irregular lumen persisted, somewhat similar to that seen in the congenital scrotal hydrocoele of humans. Tammars have a hopping mode of locomotion and, like humans, are essentially bipedal. We suggest that inguinal closure evolved in these two species because their upright posture may otherwise lead to a high incidence of inguinal hernias.

Role of the gubernacular bulb in cremaster muscle development of the rat

The role of the gubernaculum during the inguino-scrotal phase of testicular descent remains controversial. Some authors propose involution and eversion while others suggest active migration, although the site of growth is unknown. We aimed to determine whether the gubernacular bulb is actively proliferating or regressing during inguino-scrotal testicular descent in the rat. Gubernacula were removed from Sprague-Dawley rats and congenitally-cryptorchid TS mutant rats. Animals (0, 3, 7, 10, and 11 days of age) were treated with bromodeoxyuridine (BUdR) 2 hr before they were killed. BUdR incorporation into newly synthesized DNA served as a marker of cell division. The gubernacula were histologically processed for hematoxylin-eosin (H&E) and immunoperoxidase staining. Four different areas within the gubernaculum were examined for BUdR-positive cells: area 1: plica gubernaculi (cord); area 2: pars infravaginalis gubernaculi (bulb); area 3: distal part of the cremaster muscle; and area 4: proximal part of the cremaster muscle. The rate of cell division for each of these areas was determined by counting the number of BUdR-positive cells per 100 cells. The highest rate of BUdR labeling in both types of rats was in area 2, which is the tip of the gubernacular bulb, and this was significantly greater (P < 0.0001) than in the gubernacular cord or developing cremaster muscle. The mitotic activity was also noted to be significantly greater (P < 0.0001) at the distal end of the cremaster muscle than at the proximal end. The amount of mitosis decreased significantly (P < 0.01) in areas 2 and 4 of the gubernaculum in Sprague-Dawley rats across the period studied. This trend was not observed in TS rats. Our results suggest that the bulb actively proliferates after birth, with possible differentiation into new cremaster muscle cells. We propose that the bulb is the growing end of the elongating gubernaculum, analogous to the growth of a limb bud.

Inguinal canal "lipoma"

Groin dissection was performed in adult male post-mortem subjects to establish the prevalence of inguinal canal "lipoma." Thirty-six body halves (age range 24-92 years) were studied. Of these, 27 (75%) contained a discrete mass of fat within the inguinal canal. This mass was always continuous with the preperitoneal fat through the deep inguinal ring. Nineteen of these 27 masses (70%), displayed a characteristic pedunculated form with a bulbous distal end. Eighteen of the 36 dissections (50%), revealed a mass more than 4 cm in length. Six dissections showed extension of the mass beyond the superficial inguinal ring and three of these six (8% of the 36 groins studied) showed distortion of the proximal spermatic cord with a mass at the superficial inguinal ring. The masses submitted for histology comprised mature adipose tissue and all but two of these were reported as having an adherent capsule. No significant correlation was found between mass length and either subject age or body mass index (BMI) but a statistically significant correlation between the length of the fat mass on the left and right sides was shown. This study demonstrates that the inguinal canal "lipoma" is a common feature in an adult male population and may be of sufficient size to cause clinical misdiagnosis. The high prevalence, characteristic location and appearance of the "lipoma" suggest a developmental etiology.

The pectineal ligament: anatomical study and surgical applications

The aim of this study was to reinforce the importance of the pectineal ligament in laparoscopic surgery for groin hernia and female urinary incontinence, particularly its anatomical importance in the myopectineal region. A morphologic study was conducted on 44 pectineal ligaments from 23 embalmed and one fresh human cadavers, together with a radiological study on four volunteer patients. Anatomical and histological findings confirm the fact that the ligament of Cooper represents a thickening of the pectineal fascia rather than a thickening from the periosteum. The pectineal ligament provides a landmark in each approach, open or laparoscopic, anterior or posterior surgery.

Laparoscopic diagnostic exploration of the vaginal processus in the pediatric age. Preliminary experiences

BACKGROUND

Laparoscopic surgical procedures, employed even in the paediatric age, bearing both diagnostic and therapeutic value, are currently used in the evaluation of peritoneal-vaginal duct patency during surgery for controlateral inguinal hernia or other diseases requiring opening of abdominal wall.

METHODS

From January 1996 to December 2000, at the Department of Pediatric Surgery of the University of Siena a prospective study protocol has been performed to evaluate the effectiveness of laparoscopy versus traditional surgery in showing patency of peritoneal-vaginal duct.

RESULTS

From our study we have been able to see how this laparoscopic procedure is well tolerated by children and parents, and is lacking in clinical complications. Patency of peritoneal-vaginal duct has been pointed out in 21.73% of cases. This result is in line with the international literature; in fact, the majority of authors have found a negative controlateral exploration in 50-80% of patients examined, thus confirming the uselessness of routine surgical controlateral inguinal exploration in hernia cases.

CONCLUSIONS

The use of diagnostic laparoscopy in the study of peritoneal duct patency is a rapid and relatively easy technique, practically without intra- and peri operative risks. It allows an easy solution of the diagnostic doubt, without the need to necessarily perform a traditional explorative surgical procedure.

Imaging of groin masses: inguinal anatomy and pathologic conditions revisited

The groin region is subdivided into two distinct anatomic areas: the inguinal canal and the femoral triangle. A series of cross-sectional imaging cases illustrate that a good understanding of the local anatomic characteristics of the groin allows confident characterization of groin pathologic conditions. Such conditions can be classified into five major groups: congenital abnormalities, noncongenital hernias, vascular conditions, infectious or inflammatory processes, and neoplasms. Congenital entities include hernias, cysts, undescended testis, and retractile testes. Ultrasound (US) is useful in depicting these conditions. In the second group, noncongenital hernias, US allows visualization of bowel loops in peristalsis within the hernia. Herniography, computed tomography (CT), and magnetic resonance (MR) imaging are also helpful in diagnosis. Among vascular conditions, false aneurysms may be detected from the turbulent flow through the tract at Doppler US. The characteristic venous flow of varicoceles is best diagnosed with US during the Valsalva maneuver. Infectious or inflammatory conditions include, among others, hematomas, which appear hyperattenuating at CT and have variable appearances, depending on the age of the blood products, at MR imaging. The origins of neoplasms may be assessed at CT and MR imaging, although appearances of solid tumors are relatively nonspecific.

The importance of the size of Hessert's triangle in the etiology of inguinal hernia

The aim of this study was to compare the inguinal area, known as "Hessert's triangle", in patients undergoing surgical treatment for inguinal hernia with the area in fresh cadavers without hernia. The 73 cadavers, which were not fixed in formalin, were examined within 15 h post mortem. A total of 132 measurements were made in these cadavers and compared with 130 measurements in 115 hernia patients. The average age was 44.2 years for patients and 32.7 years for cadavers. The mean height and weight were 1.68 m and 69.9 kg for hernia patients and 1.67 m and 70.0 kg for the cadavers, respectively. The mean area of Hessert's triangle was 8.97 cm2 (range 2.28-29.62 cm2) in the hernia patients and 2.95 cm2 (range 1.37-5.92 cm2) in the cadavers. This difference was statistically significant (P < 0.00). A larger triangle is created by a higher intersections of the internal oblique and transversus muscles and its aponeurosis to the rectus sheath. When these muscles contract, they move toward the inguinal ligament to occlude the triangle, but with a larger triangle, the occlusion is incomplete. Our anatomical measurements verified that the size of Hessert's triangle is an important factor in the etiology of inguinal hernia.

The cutaneous nerves encountered during laparoscopic repair of inguinal hernia: new anatomical findings for the surgeon

BACKGROUND

With an incidence rate of 2%, injury to the nerves of the lumbar plexus is the most common complication of laparoscopic hernioplasty, particularly when the transabdominal preperitoneal (TAPP) technique is used.

METHODS

The course of the genitofemoral nerve, lateral femoral cutaneous nerve, and ilioinguinal nerve within the operation site was investigated in 53 adult dissecting-room bodies. Their relationship to the deep inguinal ring, iliopubic tract, and anterior superior iliac spine was also examined.

RESULTS

Both the femoral and genital branches of the genitofemoral nerve may penetrate the abdominal wall lateral to the deep ring and cranial to the iliopubic tract. The lateral femoral cutaneous nerve and the ilioinguinal nerve may run immediately lateral to the anterior superior iliac spine.

CONCLUSION

Contrary to the previously accepted opinion, dissection and the placement of staples either cranial to the iliopubic tract or lateral to the anterior superior iliac spine can result in injury to the nerves.

Radiological anatomy of the groin region

The purpose of this paper is to give an overview of the anatomy of the inguinal region, and to discuss the value of various imaging modalities in the diagnosis of groin hernias. After description of the gross anatomy of the groin, attention is focused on the anatomic features of conventional herniography, US, CT, and MRI. Advantages, disadvantages, and accuracy of each technique is discussed briefly.

Transverse subgluteal-ilioinguinal approach to the acetabulum

An approach to the acetabulum is described. This approach consists of an anterior and a posterior part. The anterior part is nearly identical with the ilioinguinal approach. The posterior part resembles Kocher's (Gibson, J Bone Joint Surg 1950;32B:183-186) original description in that the plane of dissection passes between the motor territories of the superior gluteal nerve anterolaterally and the inferior gluteal nerve posteromedially. Two modifications have been introduced, however. First, the incision is a transverse one; superior and inferior fasciocutaneous flaps are elevated. Second, the gluteus maximus is not only disinserted from the fascia lata and the gluteal tuberosity at the upper end of the femur but from the iliac crest as well. After ligating the superficial branch of the superior gluteal artery to the gluteus maximus, the muscle itself is reflected posteromedially. We have used this approach to explore the lumbosacral plexus and its branches, particularly the sciatic nerve at the greater sciatic notch. Due to the excellent exposure of both columns of the acetabulm, this approach may be equally used in fractures of the acetabulum.

Groin dissection

This review provides a brief history of groin dissection, including studies on anatomical considerations and technique. A groin dissection for complete ablation of the node-bearing areolar tissue in the inguinal and iliac regions and with negligible morbidity requires careful attention to the pathophysiology of cancer in lymphatics, pre- and postoperative care, and surgical technique, including coordinated use and general, plastic, vascular, and orthopedic surgical principles.

[Anthropometric measurements of the male inguinal canal]

BACKGROUND

A problem in the use of a prosthesis in the treatment of inguinal hernia is the form and dimension the mesh should have. There are no precise indications in the international literature and manufactured pre-cut prostheses available are not always suitable for all patients. In this study some measurements within the male inguinal canal have been compared with the patients' physical characteristics, such as weight, height and body mass index, and with inguinal hernia too. The purpose was to look for a relation between these data, in order to establish the form and size of the ideal mesh prosthesis for every patient before operation. A "list" of different prosthesis sizes could help both the surgeon and the manufacturers.

METHODS

The study was carried out on 150 male patients who underwent surgery for inguinal hernia.

RESULTS

The analysis of the results does not demonstrate a relationship between the data examined.

CONCLUSIONS

The conclusion is drawn that there could be two solutions to the problem of mesh size: one being the expensive prepacking of meshes of various sizes, and the cheaper one being to find out a method which, not considering the internal ring variability, will not influence the production of a universal mesh.

[Original procedure of functional plasty of primary inguinal hernias]

We describe a novel autoplasty method we developed for primary inguinal hernia repair and report our results in nearly 150 operations. The method is based on novel principles: priority given to an individual stato-dynamic conception of the inguinal region; effect on physiological defense mechanisms of the inguinal canal; absence of tension on the sutures by autoplastic repair.

Does the gubernaculum migrate during inguinoscrotal testicular descent in the rat?

BACKGROUND

The role of the gubernaculum in descent of the testis is controversial. The mechanism of testicular descent has been studied in the rat, because inguino-scrotal descent occurs postnatally in this species. Several authors have claimed that the cremasteric sac forms by eversion of the gubernacular cone, whereby regression of the extra-abdominal part of the gubernaculum creates a space into which the gubernacular cone everts to form the processus vaginalis within the scrotum. This postulated lack of any gubernacular migration phase contrasts with the situation in the human, where gubernacular migration appears to be an integral component of testicular descent. This study was designed to determine in the rat whether there is any gubernacular migration toward the scrotum during testicular descent, or whether eversion of the cremasteric sac alone could account for the extension of this sac into the bottom of the scrotum.

METHODS

Oblique sagittal sections of the inguino-perineal region were taken from rats aged 21 days of gestation and days 1, 3, 4, 6, 8, and 10 days postnatally. Histological sections were examined and the following measurements were obtained: gubernacular cone height, gubernaculum-scrotum distance, processus vaginalis length, and pubic symphysis-anus distance.

RESULTS

The gubernaculum was not in close proximity to the developing scrotum at any age. After 21 days of gestation, there was little evidence of a substantial gubernacular bulb distal to the processus vaginalis. At all ages the gubernacular cone height was significantly less than the distance from the gubernaculum to the scrotum.

CONCLUSIONS

These results show that the gubernaculum does not develop in close proximity to the developing scrotum. Even if complete eversion of the gubernaculum takes place, the gubernaculum would still fail to reach the bottom of the scrotum. It is proposed that gubernacular eversion is more apparent than real and that some degree of gubernacular migration is needed for complete extension of the cremasteric sac to the bottom of the scrotum.

Anatomical landmarks of the inguinal canal in prepubescent children

BACKGROUND

Most adult anatomical texts state that the deep inguinal ring is situated midway between the anterior superior iliac spine and the pubic tubercle. The aim of this study was to determine if this was true in prepubescent children.

METHODS

A total of 107 inguinal ligaments and canals were measured during inguinal operations in 80 children (68 boys, age range 1-118 months).

RESULTS

The length of the inguinal ligament increased from a median of 4.3 cm (range 3.6-6.8) at less than 1 year of age to 7.5 cm (range 6.7-10.1) at over 4 years of age. The internal ring was situated medial to the midpoint of the inguinal ligament throughout childhood. The ratio of internal ring to public tubercle over inguinal ligament length was 42% (range 27-58) at less than 2 years; and 34% (range 25-46) at over 4 years. The inguinal canal remained short (median 1 cm (range 0.7-1.1) at less than 2 years, and median 1.1 cm (range 0.7-2.3) at over 4 years) suggesting that growth of the inguinal region in this age group occurs outside the canal.

CONCLUSIONS

These results have implications for the siting of incisions, and question the necessity of opening the inguinal canal in children.

[Treatment of inguinal hernias: methods]

After a short description of the anatomy of the inguinal area, especially of muscular walls and rings, weaken areas through which hernia could appear, we describe surgical procedures, using or not prosthesis, to strength the posterior wall. The most usual procedures using no prosthesis are Bassini's, Mac Vay's and Shouldice's techniques. The procedures using prosthesis are Lichtenstein's, plug's, Stoppa and Rive's, and Pouliquen's techniques. Finally, we describe coelioscopic procedures (intra- and extraperitoneal approach). We conclude that actually, the best technique employing nonprosthesis is the Shouldice repair. Concerning techniques employing a prosthesis, we do not know, at the present time, which is the best. Clinical trials are on run to answer this question.

Anatomy of the peritoneal aspect of the deep inguinal ring: implications for laparoscopic inguinal herniorrhaphy

There are a number of important structures to be avoided in suturing or stapling during laparoscopic inguinal herniorrhaphy, not all of which are easily identifiable at laparoscopy. This is particularly so of the ductus deferens. Measurements were taken of the angle made by the ductus deferens with testicular vessels, and of the thickness of tissue in the vicinity of the internal ring into which sutures or staples are likely to be inserted. The angle (mean +/- SD) made by the ductus with testicular vessels was 38.6 degrees +/- 4.4 degrees on the right, and 48.6 degrees +/- 7.2 degrees on the left (P < 0.05) (measurements for right and left sides taken from different cadavers). Thickness of tissue around the ring (peritoneum, transversalis fascia and intervening connective tissue) varies at different sites, being greatest lateral to the testicular vessels (2.2 +/- 0.4 mm) and least over the ductus (0.2 +/- 0.1 mm). The angle measured constitutes the apex of the "triangle of doom" (Spaw et al., 1991. J. Laparoendoscopic Surg. 1:269-277) and with its use the position of the ductus deferens may be predicted and the underlying external iliac vessels avoided when stapling during herniorrhaphy.

The anatomic structure of the preperitoneal tissue (PPT) of the inguinal canal

Anatomical examinations of the inguinal canal exist in many forms. The preperitoneal tissue, the structure directly adjacent to the transverse fascia, was examined in 62 cadavers. The left side of the inguinal abdominal wall was studied with special interest in the transverse fascia and the adjacent preperitoneal tissue. In 75% of the cases the transverse fascia and preperitoneal tissue built a continuous layer. A differentiation was difficult in cadavers with cachexia or an average nutritive state. The tissues could be differentiated without difficulty in individuals with adipositas. In these cases no connection between the two layers was detected. In the medial part of the inguinal abdominal wall the tissue thickness was larger than in the lateral part. However in 32% of the cases the tissue thickness was reverse. As a consequence, the isolated suture of the transverse fascia in inguinal hernia repair is anatomically virtually impossible, if both tissues build one continuous layer.

Abdominal wall hernias

Abdominal wall hernias are usually asymptomatic, discovered incidentally on physical examination. Emergency physicians, however, may be called on to deal with the potential life-threatening complications of abdominal wall hernias. This article discusses the anatomy, pathophysiology, and specific types of hernias in the adult and pediatric patient populations. Also covered are the complications of hernias, emergency interventions for hernia reduction, and urgent surgical consultation.

Applied anatomy of the cremasteric muscle and fascia

PURPOSE

Although the cremasteric muscle is a prominent structure of the inguinal canal, specific details of its anatomy are seldom discussed in either anatomical or surgical texts. Therefore, a detailed description of the anatomy of the cremasteric muscle and fascia is provided, followed by descriptions of new applications of this knowledge for operations on the inguinal canal.

MATERIALS AND METHODS

Observations are described based on more than 1,000 operations on the inguinal canal conducted during a 15-year period. Magnification of 3.5 x was used in all dissections.

RESULTS

Careful dissections of the cremasteric muscle and fascia allowed for development of new approaches to enhance exposure of the inguinal canal and internal ring, and to mobilize the spermatic cord and testes.

CONCLUSIONS

Knowledge of the anatomy of the cremasteric muscle and fascia, and techniques for dissection are adjuncts to surgery of the inguinal canal, including inguinal hernia repair and orchiopexy.