Perineology is a new speciality that deals with the functional troubles of the three axes of the perineum [1–4]. This interdisciplinary and holistic field is approached from the angles of anatomy, biomechanics and physiology, avoiding at all costs any side effects (primum non nocere). There are seven basic, defect specific, useful surgical procedures that apply in perineology [2]. Retro-anal levator plate myorrhaphy (RLPM) is dedicated to treating the "levator plate sagging" defect.

The usual name for this levator plate sagging is descending perineum syndrome (DPS). This syndrome is well described by Parks in 1966 [5]. For this author this title is mainly descriptive, as perineal descent on straining is both the cause of symptoms and the most obvious physical sign.

For Parks, the main symptoms of DPS are dyschesia (partial and intermittent obstruction by the anterior rectal wall), pain (dull aching pain in the perineum or sacrum after defecation), bleeding or passage of mucus (prolapse of the anterior rectal wall) and anal leakage. The physical signs of this syndrome on external examination are a low position of the anus at rest or a perineal descent on straining (more than 3 cm). During this straining, the anal mucosa may pout. On rectal examination, during straining, the pubo-rectalis descends sharply and the anterior rectal wall pushes down on the examining finger. Muscle tone is easily overcome by posterior traction.

For Parks, the first step in the treatment of this syndrome consists of preventing further damages by avoiding straining during defecation and emphasizing pelvic floor reeducation.

For the most significant cases with rectal prolapse, Parks has developed a new surgical procedure called "post-anal perineorrhaphy" [6]. This procedure, also known as "post-anal repair", has been used by many other authors to treat faecal incontinence [7–13].

In 1982, Nichols used a "retro-rectal levatorplasty" to treat an uncommon type of genital prolapse characterized by descent of the anus and sagging of the levator plate associated with severe constipation [14].

In 1987, Shafik presented his experience with "levatorplasty" in the treatment of complete rectal prolapse [15].

To improve the process of defecation by reducing levator plate sagging, Nichols [14, 16] proposed using a special toilet seat with a small opening and Lesaffer [17, 18] created a "perineum device" to support the perineum. These proposals were the first "anti-sagging tests".

More recently, Beco [19] demonstrated that besides dyschesia and anal incontinence, a perineal descent of more than 1.5 cm, measured with a Perineocaliper^® during straining in the gynaecological position (with thighs flexed to 90 degrees), significantly increased the frequency of urinary incontinence, dyspareunia, dysuria, cystocele and rectocele. The frequency of the 3 clinical signs of pudendal neuropathy [20] was also significantly increased.

The first aim of this study is to show the diagnostic importance of "anti-sagging tests" on the symptoms of dyschesia, dysuria, dyspareunia, urinary incontinence, urgency and perineodynia experienced in levator plate sagging while standing. These tests can be performed by the patient herself or by the examining practitioner.

The second aim is to evaluate the effect of a simplified retro-anal levator plate myorrhaphy (RLPM) on different symptoms and on perineal position and descent during straining.

In perineology, only one specialist must treat all the symptoms of the three compartments of the perineum by using low risk and defect specific procedures.

By treating surgically only seven basic defects with their dedicated procedure it is possible to improve most of the functional troubles encountered in this area.

Abnormal levator plate sagging is one of these basic defects that must be treated in perineology [2]. This defect is quite frequent but rarely isolated.

In the 104 patients treated by RLPM, only 9 (8,6%) had an isolated procedure and represent the studied population. In the 95 other cases, one or many of the six other defect specific procedures were done together to achieve a complete restoration of the perineum. These cases were excluded from the study because each of the associated procedures can have an important effect by itself on perineal function and anatomy.

Because this study focus on the defect called levator plate sagging, its first issue is to define when this sagging is abnormal. Three methods were used to evaluate this defect: the Perineocaliper^®, rectal examination and retro-anal ultrasound.

In 1982, Henry et al studied the relationship of the anal verge to the ischial tuberosities in patients with descending perineum syndrome and compared them with normal subjects. They do not specify the name of the instrument used [26]. Some authors utilize the name "perineometer" for this instrument and perform perineometry with it [27]. Kegel had used this name many years earlier for an instrument that is introduced in the vagina to measure the increase of pressure induced by a perineal contraction [28]. The name "Perineocaliper" has been introduced because the measurement done in perineology corresponds to a depth or step measurement obtained with a Vernier caliper and the instrument has practically the same shape as a brake or skinfold caliper. With this instrument it is possible to define precisely the position of anal margin at rest, during Valsalva's maneuver or during pelvic floor contraction.

By using the Perineocaliper^® in a control group of 143 female patients, mean aged 55 years (extremes 26–81) without any symptoms, the normal position of the anal margin at rest was 0.03 cm above the ischial tuberosities (SD = 0.99) and during Valsalva 0.56 cm below these bones (SD = 0.98). The mean descent of the anal margin was 0.59 (SD = 0.54) (unpublished data). According to these data, a descent of more than 1.67 cm is unusual in a control group.

Therefore, it seems that a perineal descent of more than 1.5 cm during a Valsalva's maneuver is abnormal.

Henry [26], using an old version of the same instrument, found different values in his control group of 55 women (mean age 48 years): at rest + 2.5 cm (SD = 0.6), during "bears down" like in defecation + 0.9 cm (SD = 1). There are three main differences between the two studies: the mean age of the control group (48 versus 55 years), the position of the patient during the measurement (left lateral versus gynecological position) and the type of effort ("bears down" like in defecation versus Valsalva's maneuver). They could explain the different results obtained.

Measuring the descent of the anal margin is an indirect method of evaluating levator plate sagging. In fact, theoretically the descent of the anal margin is greater in cases of a longer levator plate for the same angle. Therefore it seems logical to evaluate the angle itself.

This evaluation is possible by rectal examination as proposed by Shafik [15]. The three levels ordinal scale used in this study was very useful in the indication of RLPM (grade 2 = complete sagging) and at the end of the myorrhaphy (grade 0 = no sagging). Other methods like colpocystodefecography, magnetic resonance imaging or ultrasound must be used to obtain more precise data.

For Costalat et al [29] using colpocystodefecography in a sitting position, the normal angulation of the posterior rectal wall at rest is less than 20 degrees with the horizontal. During defecation, the angle of sagging must be less than 20 degrees.

For Hsu et al [30] using dynamic nuclear resonance magnetic imaging in a supine position, the mean angulation of the levator plate with the vertical plane at rest was 36.2 degrees (SD = 12.3) and during Valsalva's maneuver 44.3 degrees (SD = 15.2). With respect to the control group, there was a significant increase of 9.1 degrees in the levator plate angle during Valsalva in case of prolapse.

Retro-anal ultrasound (done in a gynecological position) is a new easily available method that enables the study of the levator plate angle. In a control group of 40 female patients (unpublished data), with a mean age of 51 years (extremes: 23–81) the mean value of the angles at rest was 19.7 degrees (SD = 8.8 degrees) and during Valsalva 30.5 degrees (SD = 10.7 degrees). The mean sagging angle (difference between Valsalva and rest angles) was 10.8 degrees (SD = 8.2 degrees). This method has been used to evaluate the changes in angles induced by surgery, but not as an inclusion criteria for surgery because it is still being validated.

Anti-sagging tests must be used to prove that perineal descent is the cause of one symptom. By supporting the posterior perineum, these tests suppress levator plate sagging and simulate the effect of RLPM. It must be used to confirm the indication to perform a RLPM, but it may also be used as a part of the non-surgical treatment of a descending perineum syndrome. Especially in case of dyschesia or dysuria, the improvement of micturition or defecation by moving back as much as possible on the toilet seat can be so important that it can stop the vicious circle: straining => perineal descent (stretching of the pudendal nerve) => straining. Ideally, the back part of the toilet seat must be large enough and only slightly tilted to support perfectly the posterior perineum. The same approach was proposed by Lesaffer [17, 18] and Nichols [14, 16] who suggest the use of special toilet seats or supports to improve defecation.

Overload of the "suspensor structures" (pubo-rectalis, utero-sacral ligaments, vaginal scars, transverse muscles) induced by levator plate sagging is a newly discovered cause of perineodynia and dyspareunia which must be differentiated from pudendal neuropathy [31] or muscular pain [32]. Contrary to the two other causes, pain induced by levator plate sagging is usually increased while standing and reduced while sitting. It is suppressed by the anti-sagging test. This test is also very helpful to confirm that perineal descent is the cause of dyspareunia.

The same differential diagnosis must be done in cases of urinary frequency, urgency and urge incontinence where pudendal neuropathy [20, 33] and muscular trigger points [34] may also be involved. Again, in cases of levator plate sagging, the symptoms are worse in a standing position and disappear when the posterior perineum is lifted with the hand.

The intersphincteric plane has been avoided because this approach can damage the thin anal sphincter and the operating field is reduced. After having used retro-anal U-shaped skin incision (Shafik's levatorplasty [15]) in our first cases (not included in this case series), we decide to make midline skin incisions which are less painful. Only myorrhaphy of the levator plate has been done because the pubo-rectalis is included in the upper part of the anal sphincter and is not available for suture by the retro-anal approach. Furthermore, stitches in this muscle would damage it and therefore reduce its contractile force. To reduce the risk of injury to the rectum, the rectal neck was not attached to the edge of the levator plate (this step is probably necessary in cases of rectal prolapse [15]) and the pelvis was not opened.

In the literature, the main indication of post-anal repair was idiopathic anal incontinence. The long term results vary from 90% cured in the old studies to 35% cured in the more recent ones [7–10]. Nichols [14] used retro-rectal levatorplasty to treat isolated dyschesia with anal descent. Shafik [15] proposed levatorplasty to treat dyschesia associated with complete rectal prolapse.

In this short case series, besides anal incontinence and dyschesia, RLPM has been effective on most of the functional troubles of the perineum. Of course the number of cases is too small to draw definitive conclusions. This new solution may though be very useful to treat difficult problems such as urinary urgency, dysuria, dyspareunia or perineodynia. For stress urinary incontinence, RLPM is not a first line treatment because less invasive and more specific procedures exist but it could be helpful in some difficult cases.

Athanasiadis [9] found no significant difference in pelvic descent and ano-rectal angle after post-anal repair. After the same surgical procedure, Orrom [11] and Van Tets [12] did not find any difference either in the ano-rectal angle. In this study, levator plate sagging was reduced independently from the evaluation method used. This difference may be due to the smaller number of cases, to a shorter follow-up or to the different surgical approach.

Jameson [8] and Athanasiadis [9] didn't find any significant change in the motor latencies of the pudendal nerve after post-anal repair. In this study, the effect on pudendal neuropathy is unclear. By reducing the stretching on the pudendal nerve, RLPM should normally improve pudendal nerve function. This result has been observed clinically in 50% of the cases. The appearance of some clinical signs of pudendal neuropathy after surgery is quite surprising. Maybe it is linked to the formation of adhesions in the ischio-rectal fossae or the appearance of trigger points in the pelvic floor muscles. Further studies are necessary to better understand this side effect.

RLPM is one defect specific treatment of levator plate sagging, but of course other surgical procedures could reduce perineal descent as well. The patient with rupture of the RLPM has been re-operated successfully. The procedure used was part of a full defect restoration project [2] and included the treatment for rectocele, cystocele and urinary incontinence using the vaginal route. Without any statistical proof, this multi-layer operation seems to be more logical to reduce the load on the RLPM. In fact each layer (anterior vaginal wall, sub-urethral support, posterior vaginal wall, perineal body) absorbs a part of the pressure, therefore reducing the tension on the levator plate myorrhaphy. Conversely, RLPM should reduce the load on genital prolapse repairs and the risk of recurrence.

In our full experience with RLPM, the main risk is ischio-rectal fossae infection (not encountered in this case series). This risk seems to be reduced by the use of a multi-tubular drain for 5 days, antibiotic coverage and intestinal preparation before surgery.

Dyschesia and anal incontinence are only a small part of the problems induced by pathological sagging of the levator plate. In fact, perineal descent of more than 1.5 cm significantly increases the frequency of all the functional troubles related to the perineum.

RLPM can treat levator plate sagging, perineal descent and all the symptoms associated with this defect (stress urinary incontinence, frequency, urgency, dysuria, anal incontinence, dyschesia, dyspareunia, perineodynia and prolapse). Anti-sagging tests must be used to confirm the role of this sagging in the origin of these symptoms. A clear positive test is mandatory before surgery is indicated. Sometimes though, simply moving back on the toilet seat during defecation and micturition is enough to treat the patient's problem, avoiding the need for physiotherapy or surgery.

Many symptoms induced by levator plate sagging may be seen in cases of pudendal neuropathy or pelvic floor muscle trigger points. The perineology specialist must be aware of all these etiologies to obtain good results for his patients.