Descending perineal syndrome cure by deep transversus perinei ligament repair: surgical options.

Descending perineal syndrome (DPS) was described by Parks et al. as descent of the anus on straining, typically 3-4 cm below a line drawn from the coccyx to the lower end of the. DPS is associated with obstructed defecation, with increased bulging of the perineum with straining, although perineal descent can also be seen at rest. In their review, Chaudhry and Tarnay stated: "It is controversial whether surgical management is even an option for patients with DPS". The deep transversus perinei (DTP) ligaments are the suspensory ligaments of the perineal body (PB). DTP are approximately 4 cm long. They attach behind the upper 2/3 and lower 1/3 of the descending ramus. If, at childbirth, the PB is overstretched and displaced laterally and inferiorly, the DTP lengthens. DPS is described as descent of the anus on straining, typically 3-4 cm below a line drawn from the coccyx to the lower end of the symphysis. DPS is associated with obstructed and often, assisted defecation, with increased bulging of the perineum with straining descent of the anus on straining. The surgical methodology begins as a standard PB repair which dissects the rectum from the vagina and PB and approximates the displaced components of the PB. We added an additional step: identifying the DTPs, shortening and reinforcing them with the Tissue Fixation System (TFS) minisling or No. 2 polyester sutures. High cure rates for obstructed defecation were achieved with the TFS minisling, and initial results using No. 2 polyester sutures are favourable. The key messages from both operations is DPS is caused by stretching and elongation of DPS ligaments, and these are surgically repairable.

Perineoplasty for anal incontinence after obstetric anal sphincter injury repair: a case report.

BACKGROUND: The rectal and vaginal walls are typically sutured if severe perineal lacerations with rectal mucosal damage occur during vaginal delivery. In case of anal incontinence after the repair, re-suturing of the anal sphincter muscle is standard procedure. However, this procedure may not result in sufficient improvement of function. CASE PRESENTATION: A 41-year-old woman underwent suture repair of the vaginal and rectal walls for fourth-degree perineal laceration at delivery. She was referred to our department after complaining of flatus and fecal incontinence. Her Wexner score was 15 points. Examination revealed decreased anal tonus and weak contractions on the ventral side. We diagnosed anal incontinence due to sphincter dysfunction after repair of a perineal laceration at delivery. We subsequently performed sphincter re-suturing with perineoplasty to restructure the perineal body by suturing the fascia located lateral to the perineal body and running in a ventral-dorsal direction, which filled the space between the anus and vagina and increased anal tonus. One month after surgery, the symptoms of anal incontinence disappeared (the Wexner score lowered to 0 points), and the anorectal manometry values increased compared to the preoperative values. According to recent reports on the anatomy of the female perineal region, bulbospongiosus muscle in women does not move toward the midline to attach to the perineal body, as has been previously believed. Instead, it attaches to the ipsilateral surface of the external anal sphincter. We consider the fascia lateral to the perineal body to be the fascia of the bulbospongiosus muscle. CONCLUSIONS: In a case of postpartum anal incontinence due to sphincter dysfunction after repair of severe perineal laceration, perineoplasty with re-suturing an anal sphincter muscle resulted in improvement in anal sphincter function. Compared to conventional simple suture repair of the rectal wall only, this surgical technique may improve sphincter function to a greater degree.

Functional Anatomy of Urogenital Hiatus Closure: the Perineal Complex Triad Hypothesis.

INTRODUCTION: Urogenital hiatus enlargement is a critical factor associated with prolapse and operative failure. This study of the perineal complex was performed to understand how interactions among its three structures: the levator ani, perineal membrane, and perineal body-united by the vaginal fascia-work to maintain urogenital hiatus closure. METHODS: Magnetic resonance images from 30 healthy nulliparous women with 3D reconstruction of selected subjects were used to establish overall geometry. Connection points and lines of action were based on perineal dissection in 10 female cadavers (aged 22-86 years), cross sections of 4 female cadavers (aged 14-35 years), and histological sections (cadavers aged 16 and 21 years). RESULTS: The perineal membrane originates laterally from the ventral two thirds of the ischiopubic rami and attaches medially to the perineal body and vaginal wall. The levator ani attaches to the perineal membrane's cranial surface, vaginal fascia, and the perineal body. The levator line of action in 3D reconstruction is oriented so that the levator pulls the medial perineal membrane cranio-ventrally. In cadavers, simulated levator contraction and relaxation along this vector changes the length of the membrane and the antero-posterior diameter of the urogenital hiatus. Loss of the connection of the left and right perineal membranes through the perineal body results in diastasis of the levator and a widened hiatus, as well as a downward rotation of the perineal membrane. CONCLUSION: Interconnections involving the levator ani muscles, perineal membrane, perineal body, and vaginal fascia form the perineal complex surrounding the urogenital hiatus in an arrangement that maintains hiatal closure.

Ultrasonographic study of female perineal body and its supportive function on pelvic floor.

Objectives: The study aimed to observe, measure the size and elastic value of perineal body (PB) and assess its association with levator hiatus. Methods: Datasets were acquired in 45 nulliparous, 66 POP women and 70 postpartum women using ultrasound. The PB was measured in depth, height, and Young's modulus. The datasets were compared to assess whether there are some differences in the morphology, dimension and elastography modulus of PB among women. Pearson correlation analysis was used to evaluate the association between the morphology measurements (ΔValsalva-rest[v-r]), tissue mechanical properties (ΔValsalva-rest[v-r]) of the PB and levator hiatus area (ΔValsalva-rest[v-r]) to preliminarily explore whether PB can influence levator hiatus. Results: Four representative manifestations of PB were presented in our study. Nulliparous women had smaller diameters and bigger Young's modulus while postpartum women had bigger diameters and smaller Young's modulus. POP and postpartum women had bigger levator hiatal distensibility and PB extensibility. There was no statistical association between PB measurements and levator hiatal area. Conclusion: It is feasible to observe the morphology of PB and assess the dimension and elastography modulus by high-frequency ultrasound. The manifestations and measurements of PB are influenced by parity and long-term increased abdominal pressure. Our study preliminarily shows that PB has little effect on levator hiatus area.

Perineal body squamous cell carcinoma treated with radical radiotherapy - a case report.

Introduction: Perianal tumours are a rare site of malignancy, and tumours primarily involving the perineal body without vaginal and anal canal involvement are uncommon. Case summary: A 67-year-old woman presented with a lesion involving the perineum and rectovaginal septum without extension into vaginal or anorectal mucosa and with skip lesions in the vulva. Biopsy was confirmative of squamous cell carcinoma, with p16 positive. A complete metastatic workup with MRI of the pelvis and CECT thorax and abdomen was done. She was diagnosed with perianal carcinoma stage cT2N0M0 Stage II (American Joint Committee on Cancer 8th Edition of Cancer Staging) since the lesion reached the anal verge. Given the location of the tumour (perineal body), comorbidities and advanced age, she received radical radiotherapy with an intensity-modulated radiotherapy technique - 56 Gy in 28 fractions with the intention of organ preservation. The response assessment with MRI at 3 months showed a complete tumour response. She has been disease-free for 3 years and is on regular follow-ups. Conclusion: Isolated perineal body squamous cell carcinomas are unusual, and synchronous vulvar skip lesion makes this case unique. Radical radiotherapy achieved organ preservation with tumour control and minimal toxicity in an elderly frail patient.

Pelvic floor and perineal muscles: a dynamic coordination between skeletal and smooth muscles on pelvic floor stabilization.

The purpose of this review is to present our researches on the pelvic outlet muscles, including the pelvic floor and perineal muscles, which are responsible for urinary function, defecation, sexual function, and core stability, and to discuss the insights into the mechanism of pelvic floor stabilization based on the findings. Our studies are conducted using a combination of macroscopic examination, immunohistological analysis, 3D reconstruction, and imaging. Unlike most previous reports, this article describes not only on skeletal muscle but also on smooth muscle structures in the pelvic floor and perineum to encourage new understanding. The skeletal muscles of the pelvic outlet are continuous, which means that they share muscle bundles. They form three muscle slings that pass anterior and posterior to the anal canal, thus serving as the foundation of pelvic floor support. The smooth muscle of the pelvic outlet, in addition to forming the walls of the viscera, also extends in three dimensions. This continuous smooth muscle occupies the central region of the pelvic floor and perineum, thus revising the conventional understanding of the perineal body. At the interface between the levator ani and pelvic viscera, smooth muscle forms characteristic structures that transfer the lifting power of the levator ani to the pelvic viscera. The findings suggest new concepts of pelvic floor stabilization mechanisms, such as dynamic coordination between skeletal and smooth muscles. These two types of muscles possibly coordinate the direction and force of muscle contraction with each other.

Surgical management of traumatic perineal injury in female children: A report of two cases.

INTRODUCTION AND IMPORTANCE: Perineal trauma is uncommon in paediatric population,accounting for about 0.2 to 8 % of all paediatric trauma. The goal of surgical management is to ensure adequate anatomical reconstruction with good functional outcome and cosmesis. A novel surgical technique derived from posterior sagittal anorectoplasty (PSARP)was recently described for reconstruction of perineal injuries due to sexual assault in children. We report our experience with the utilization of this technique for perineal reconstruction in 2 girls with fourth-degree traumatic genito-anal injury. CASE PRESENTATION: The first patient is a 6 year old girl who presented 2 months post perineal injury following a fall.Previous multiple attempts at repair in peripheral hospital failed.She had Initial debridement,wound irrigation and divided sigmoid colostomy for stool diversion done.Definitive reconstruction was performed 5 months later.The second patient is a 14 year old girl that presented 6 days following perineal trauma sustained while riding a bicycle.Primary repair was also attempted before referral,with subsequent wound breakdown.Wound debridement and colostomy creation was done and surgical reconstruction carried out 6 months later.Following definitive repair,the colostomies in both patients were closed at 2 and 3 months respectively.Both patients are fully continent of stool and have excellent cosmetic outcome during postoperative follow up. CLINICAL DISCUSSION: The surgical technique allows for effective dissection and proper reconstruction of the perineal body and anorectal sphincters.It also avoids unnecessary dissection and tissue disruption as the intact posterior rectal wall and anal sphincters are left undisturbed. CONCLUSION: The Surgical technique derived from the principles of posterior sagittal anorectoplasty gives excellent functional outcome in perineal trauma.

Saving the perineal body-A modification of the posterior sagittal anorectoplasty.

BACKGROUND: Wound dehiscence of the anocutaneous anastomosis and/or reconstructed perineal body is a feared perioperative complication after posterior sagittal anorectoplasty (PSARP). Dehiscence of the perineal body can have long-term negative implications for fecal continence, sexual intimacy, obstetrical outcomes, and the need for reoperative surgery. We describe a modification to the traditional PSARP for repair of an imperforate anus with a rectovestibular, perineal, or absent fistula by sparing the perineal body, eliminating postoperative perineal body dehiscence and potentially improving long-term functional outcomes. METHODS: A retrospective review of female patients with a rectovestibular, perineal, or absent fistula who underwent PSARP with sparing of the perineal body was performed. RESULTS: Six patients underwent PSARP with sparing of the perineal body between 2019 and 2022. There were no perioperative complications. At follow-up, all patients are having regular bowel function without difficulty and have an excellent appearance of their perineal body. CONCLUSIONS: PSARP for a rectovestibular, perineal, or absent fistula can be safely performed with a more limited incision to avoid disruption of the perineal body. This eliminates the need for perineal body reconstruction during the procedure, thereby preventing wound dehiscence. Given the significant long-term adverse sequelae of wound dehiscence and resultant inadequate perineal body, we believe this modification to the PSARP warrants strong consideration.

Short and long term results of anatomical reconstruction of perineal body and sphincter complex in obstetric anal sphincter injuries.

Objectives: The effective way to reduce the risk of fecal incontinence (FI) in primary repaired obstetric anal sphincter injuries (OASIS) patients is to accurately detect the injury and provide complete anatomical reconstruction. The aim of the study was to evaluate the short-term and long-term results of OASIS cases that were diagnosed by an experienced surgical team and whose perineal body and anal sphincters were reconstructed separately. Material and Methods: Sixteen patients that required consultations due to anal sphincter damage during vaginal delivery and underwent anatomical reconstruction due to Grade 3c and Grade 4 sphincter damage between 2007 and 2019 were included in the study. These cases were divided into three groups [Group 1 (≤12 months), Group 2 (12-60 months), Group 3 (≥60 months)] according to the time elapsed until anal manometry, and incontinence questionnaires were conducted in the postoperative period. Recto-anal inhibitory reflex (RAIR), mean resting (IB) and squeezing (SB) pressures were measured by anal manometry. Anal incontinence (AI) and FI rates were determined by questionnaires. Anal sphincter damage repair techniques (overlapping, end-to-end) were determined. These parameters were compared between the three groups. Results: Mean age of the patients was 27.5 (16-35) years. Six (37.5%) patients had Grade 3c, while 10 (62.5%) had Grade 4 injury. The overall mean RP and SP were 35 (26-56) mmHg and 67 (31-100) mmHg, respectively. Mean RP and SP were 46/67 mmHg, 33.5/75.5 mmHg, and 37.5/70.5 mmHg in Groups 1, 2, and 3 respectively. There was no difference between the three groups in terms of mean RP and SP (p= 0.691, p= 0.673). The rate of AI and FI in all patients were 18.75% and 12.5%, respectively while the rate of severe AI incontinence was 6%. Severe AI was observed in 1 (16.7%) case in Group 1, mild AI was observed in 1 (25%) case in group 2, and in 1 (16.7%) case in Group 3. RAIR was positive in all patients. In Group 1, 5 (83.3%) patients underwent overlapping repair, and in Group 3, 6 (100%) patients underwent end-to-end repair. This difference was statistically significant (p= 0.011). Conclusion: In vaginal births, evaluation of anal sphincter damage, determination of perineal body structures and anal sphincters separately and performing anatomical reconstruction when needed significantly reduce the rate of FI in the short and long term.

High Uterosacral Ligament Fixation Versus McCall's Culdoplasty for Vaginal Vault Suspension in Utero-Vaginal Prolapse Surgery.

INTRODUCTION:  There are high chances of post-hysterectomy vault prolapse (PHVP) if the vault is not well supported after vaginal hysterectomy in cases of pelvic organ prolapse (POP). High uterosacral ligament suspension (HUSLS) and McCall's culdoplasty are the well-recommended modalities to suspend the vault after vaginal hysterectomy. As both the procedures are accessible to non-urologic gynaecologists, the study was planned in cases of POP.  Objective: The study was conducted to compare the anatomic and functional outcomes of patients undergoing vaginal HUSLS vs. McCall's culdoplasty at the time of vaginal hysterectomy. MATERIALS AND METHODS: This prospective interventional study was done in a tertiary care hospital. A total of 80 patients were included and divided into two groups of 40 patients each. In one group, patients underwent high uterosacral ligament suspension and in the second group, McCall's culdoplasty was done for vault suspension. All procedures were done by two trained surgeons. The effectiveness of both the procedures was assessed by preoperative and postoperative pelvic organ prolapse quantification (POP-Q) (up to two years). Patients were followed for two years to see for any postoperative problem/recurrence. RESULTS: Vault suspension by HUSLS showed better results than McCall's culdoplasty, in terms of POP-Q point C, perineal body (PB), genital hiatus (GH) and total vaginal length (TVL) as compared to McCall's culdoplasty. CONCLUSION:  The anatomical correction is much better with HUSLS, which suspends the vault in the normal vaginal axis. However, it takes longer compared to McCall's culdoplasty, so the procedure should be individualised and performed with several precautions.

45 years' experience with early childhood anatomical technique of feminising genitoplasty for 46 XX Congenital Adrenal Hyperplasia -observations of vaginal introital anatomy and its relationship to the perineal body.

In Manchester, feminising genitoplasty is offered to children with 46XX Congenital Adrenal Hyperplasia (CAH) when there is a single perineal opening and/or enlarged clitoris. Our aims are to describe the anatomical reconstructive technique and present long-term outcomes. Our hypothesis is that 'the common channel (CC) length and distance to the vagina from perineal skin is mostly due to virilisation and hypertrophy of perineal tissue over the almost normally positioned vaginal introitus (V-I) in relation to the perineal body (PB)'. METHOD AND RESULTS: This is a retrospective notes review of all consecutive 46XX CAH operations from 1976 to December 2021. 99 patients, who had feminising genitoplasty and being followed-up, were included. 15 patients who were lost to follow up were excluded. Median age at surgery was 15 months. In 91, midline division of the labia majora, spongiosum, bulbo-spongiosus muscle (BSM) and CC down to PB was performed. This was sufficient to expose the V-I at the same level or within 5 mm depth of PB in 88. In 78 V-I was adequate taking 10/12fr dilator (Type 1). In 10, CC resembled a male urethra and V-I was narrow (Type 2), requiring widening by 5-10 mm incision at 6 o'clock position. Dartos of labia majora was attached to BSM to reduce the distance to V-I from perineal skin and the gap was lined with inner foreskin to create a vestibule. Out of 70 who were post-pubertal, 75% (53/70) had adequate calibre vaginal openings. 5 had introitoplasty and 2 had dilatation under anaesthesia. 10 needed self dilators only. 29 patients, of one of the three surgeons, had measurements of clitoris, CC, urethra and vagina. A hymen was found in 86% (25/29). There was significant strong, inverse correlation between the CC length and the urethral length (r = -0.708, p < 0.001, n = 27) but not between CC and vaginal lengths. After adjusting for age, the urethral length of Type 2 patients was 3.825 mm shorter than those of Type 1 (p = 0.017). CONCLUSION: Our data show that 'high' confluence is mostly due to virilisation of genitalia; and the anatomical technique of reversing the fusion of the urethral folds, spongiosum and bulbo-spongiosus muscle could be performed with all degrees of virilisation with success in early childhood with no need of local flaps or mobilisation of the urethro-vaginal complex. About 10% require surgery to treat narrowing of vaginal opening post puberty.

Pelvic Organ Prolapse Quantification (POP-Q) system needs revision or abandonment: The anatomy study.

OBJECTIVE: To examine the female urogenital hiatus (UGH) and perineal body gross and topographic anatomy; to analyze the POP-Q recommendation for evaluating UGH and PB. STUDY DESIGN: A prospective case series study on fifteen fresh human adult female cadavers was conducted in international settings. Stratum-by-stratum, macro-, and micro-anatomical dissections to study the UGH and PB gross-topographic anatomy. In addition, HGH and PB descriptive anatomy presented in the medical literature were analyzed. The primary outcome measured the accuracy of POP-Q in the assessment of UGH and PB. Additionally, digital photos were taken to document UGH and PB gross and topographic anatomy. RESULTS: The present study confirmed that the urogenital hiatus was a well-described structure in the medical literature. It is an oval-shaped structure that originated at the inferior pubic bone and was inserted into the posterior anal wall and superior surface of the PB. In all subjects, the location of UGH was in the Retzius space. Therefore, the recommendation by the POP-Q to evaluate UGH from the middle urethral meatus to the posterior hymeneal ring was incorrect because it did not accurately reflect the total longitudinal diameter of UGH. The PB topographic anatomy was not appropriately described in the literature. PB was an oval-shaped, solid, muscular mass without the central point of the perineum or fascia and rested between the posterior-distal vaginal wall and the anterior anorectal wall in a horizontal orientation and was not a part of the posterior perineum as the POP-Q system indicated. Therefore, a vertical measurement of the perineal body as recommended by POP-Q was impossible to obtain due to its horizontal orientation under the posterior-distal vaginal wall; PB had to be measured horizontally. The median length was 4.2 cm ± 1.6 (SD). CONCLUSIONS: The POP-Q system does not adequately assess UGH and PB and needs revision.

Gluteoperinealis muscle: a surgically important variation.

BACKGROUND: Anatomical variations are common in gluteal region. This report presents two cases of gluteoperinealis muscles detected during radiological imaging. CASE PRESENTATION: Our study was conducted on two patients. This report describes an accessory muscle detected in the gluteal region on MRI examination of a patient who admitted to our clinic after a firearm injury and a second patient examined with CT imaging who had signs of pelvic infection. In the first case, this accessory muscle originated bilaterally from the fascia of the gluteus maximus throughout its posteromedial side and was attached to the perineal body. In the second case, it extended forward from the fascia of the gluteus maximus muscle and inserted to the cavernous body of penis on the left side and to the perineal body on the right. In the literature, this accessory muscle has been described as the gluteoperinealis muscle being a rare variation. CONCLUSION: Considering the origin and insertion of the muscle, this variation may be important during the surgical operations of the gluteal and perineal regions.

The effect of the birth method on changes of the prepartum and postpartum dimensions of perineal body.

OBJECTIVE: The perineal body is critical for maintaining the integrity of the pelvic floor, especially in females as it can be injured during vaginal delivery. This study aimed to evaluate the effect of childbirth on perineal body dimensions by using a transperineal 2D ultrasound. STUDY DESIGN: This prospective cohort study was performed in a tertiary obstetric care center. A total of 172 term pregnant women who delivered either by cesarean section or vaginal delivery were enrolled in the study. All demographic data and information were collected prospectively. The perineal body was measured in length, height, perimeter, and area. Mode of delivery was classified into four categories, including prelabor cesarean section, cesarean section during the first stage of labor, the first vaginal delivery, and more than one previously vaginal delivery. A postpartum evaluation was performed after 6 weeks. RESULTS: Among the 172 women, 40 (23.3 %) had a history of cesarean section (CS) and they delivered with scheduled CS, 40 (23.3 %) women delivered by primary CS during active labor, 48 (27.9 %) women had the first vaginal delivery, 44 (25.6 %) women who delivered vaginally had a history of at least one vaginal delivery. The postpartum perineal body measurements were significantly lower in terms of length, perimeter, and area in all pregnancy groups. CONCLUSION: Pregnancy and delivery change perineal body dimensions, significantly. Cesarean section does not completely protect against changes in perineal body morphology.

Perineal body length and prevention of perineal lacerations during delivery in cameroonian primigravid patients.

OBJECTIVE: The rate of perineal tears in Cameroonian primiparous women is reported to be up to 59.7%. The present study aimed to assess the relationship between perineal length and perineal tears. METHODS: We conducted a prospective study of primiparous women with singleton pregnancies of at least 36+6  weeks length. The admitting physician measured the length of the perineal body at the first stage of labor and this value was hidden from the delivery personnel until delivery occurred. The presence of perineal trauma and other delivery characteristics were recorded. Data were analyzed using univariate analyses and multiple logistic regression. RESULTS: The mean perineal body length was 3.21 ± 0.75 cm (range 1.5-5.5 cm). 34 (33.0%) primiparous women sustained spontaneous perineal tears and 20 (19.4%) had episiotomies. No third- or fourth-degree perineal tears were observed. Perineal body length shorter than 2.5 cm was a significant (P < 0.04) predictor of spontaneous perineal lacerations (58.3% vs. 29.7% with relative risk 0.59). Both duration of second stage of labor longer than 60 min and occiput posterior presentation were associated with an increased risk of episiotomy in primiparous patients. CONCLUSION: Perineal body length less than 2.5 cm significantly predisposed to spontaneous perineal lacerations.

Ultrasound imaging of the perineal body: a useful clinical tool.

INTRODUCTION AND HYPOTHESIS: The perineal body is a fibromuscular pyramidal structure located between the vagina and the anus. It has been difficult to image because of its small size and anatomical location. This study used 2D transperineal ultrasound to measure the perineal body and assess whether there is an association with prolapse. METHODS: An observational, cross-sectional study was carried out in a tertiary level Urogynaecology department and included prolapse patients and healthy nulliparous volunteers (control group). This was a clinical assessment, including POP-Q and trans-perineal 2D ultrasound measurement of the perineal body height, length, perimeter, and area. Parametric tests were used, as the data were normally distributed. Results are reported as mean and 95% confidence interval (±95% CI). RESULTS: A total of 101 participants were recruited of which 22 were nulliparous healthy volunteers. Mean perineal body measurements in controls were height 22.5 ± 3.3 mm, length 17.4 ± 2.7 mm, perimeter 7.5 ± 0.9 mm, and area 2.8 ± 0.38 cm2. Perineal body measurements in 79 prolapse patients: height 16.9 ± 1.7 mm, length 16.0 ± 1.4 mm, perimeter 6.5 ± 0.5 mm and area 2.1 ± 0.5 cm2. A small perineal body was strongly associated with posterior compartment prolapse (paired t test, p < 0.0001) and wider POP-Q GH (paired t test, p = 0.0003). Surprisingly, Pelvic Organ Prolapse Quantification Perineal Body (POP-Q PB) of the two groups was not significantly different. A perineal body mid-sagittal area of less than 2.4 cm2 has been shown to be associated strongly with posterior compartment prolapse. CONCLUSIONS: It is possible to measure the perineal body on 2D ultrasound. This technique facilitates the objective diagnosis of perineal deficiency. POP-Q PB does not predict the length or area of the perineal body.

Interactive three-dimensional teaching models of the female and male pelvic floor.

Controversies regarding structure and function of the pelvic floor persist because of its poor accessibility and complex anatomical architecture. Most data are based on dissection. This "surgical" approach requires profound prior knowledge, because applying the scalpel precludes a "second look." The "sectional" approach does not entail these limitations, but requires segmentation of structures and three-dimensional reconstruction. This approach has produced several "Visible Human Projects." We dealt with limited spatial resolution and difficult-to-segment structures by proceeding from clear-cut to more fuzzy boundaries and comparing segmentation between investigators. We observed that the bicipital levator ani muscle consisted of pubovisceral and puborectal portions; that the pubovisceral muscle formed, together with rectococcygeal and rectoperineal muscles, a rectal diaphragm; that the external anal sphincter consisted of its subcutaneous portion and the puborectal muscle only; that the striated urethral sphincter had three parts, of which the middle (urethral compressor) was best developed in females and the circular lower ("membranous") best in males; that the rectourethral muscle, an anterior extension of the rectal longitudinal smooth muscle, developed a fibrous node in its center (perineal body); that the perineal body was much better developed in females than males, so that the rectourethral subdivision into posterior rectoperineal and anterior deep perineal muscles was more obvious in females; that the superficial transverse perineal muscle attached to the fibrous septa of the ischioanal fat; and that the uterosacral ligaments and mesorectal fascia colocalized. To facilitate comprehension of the modified topography we provide interactive 3D-PDFs that are freely available for teaching purposes. Clin. Anat. 33:275-285, 2020. © 2019 Wiley Periodicals, Inc.

Novel simulations to determine the impact of superficial perineal structures on vaginal delivery.

This study's aim was to determine whether the inclusion of superficial perineal structures in a finite-element simulation of vaginal delivery impacts the pubovisceral muscle and perineal body, two common sites of birth-related injury. The hypothesis, inferred from prevailing literature, was that these structures would have minimal influence (differences less than ±10%). Two models were made using the Visible Human Project's female cadaver to create a rigid, fixed pelvis, musculature held by spring attachments to that pelvis, and a rigid, ellipsoidal fetal head prescribed with an inferior displacement to simulate delivery. Injury site stretch ratios and fetal head and perineal body displacements and angles of progression were compared between the Omitted Model (which excluded the superficial perineal structures as is common practice) and the Included Model (which included them). Included Model stretch ratios were +107%, -9.84% and -14.6% compared to Omitted Model perineal body and right and left pubovisceral muscles, respectively. Included Model peak perineal body inferior displacement was +72.5% greater while similar anterior-posterior displacements took longer to reach. These results refute our hypothesis, suggesting superficial perineal structures impact simulations of vaginal delivery by inhibiting perineal body anterior-posterior displacement, which stretches and inferiorly displaces the perineal body.

Anatomy of the smooth muscle structure in the female anorectal anterior wall: convergence and anterior extension of the internal anal sphincter and longitudinal muscle.

AIM: The anatomy of the region between the vagina and anal canal plays an essential role when performing a proctectomy for low-lying tumours. However, the anatomical characteristics of this area remain unclear. The purpose of the present study was to clarify the configuration, and both lateral and inferior extensions, of the muscle bundles in the anorectal anterior wall in females. METHODS: Using cadaveric specimens, macroscopic anatomical and histological evaluations were conducted at the anatomy department of our institute. Macroscopic anatomical specimens were obtained from six female cadavers. Histological specimens were obtained from eight female cadavers. RESULTS: The smooth muscle fibres of the internal anal sphincter and longitudinal muscle extended anteriorly in the anorectal anterior wall of females and the muscle bundles showed a convergent structure. The anterior extending smooth muscle fibres merged into the vaginal smooth muscle layer, distributed subcutaneously in the vaginal vestibule and perineum and spread to cover the anterior surface of the external anal sphincter and the levator ani muscle. Relatively sparse space was observed in the region anterolateral to the rectum on histological analysis. CONCLUSION: Smooth muscle fibres of the rectum and vagina are intermingled in the median plane, and there is relatively sparse space in the region anterolateral to the rectum. Therefore, when detaching the anorectal canal from the vagina during proctectomy, an approach from both the lateral sides should be used.