26 Surgical Treatment of Puborectalis Hypertrophy De-hong Yu and Hei-ying Jin

Defecation is a complicated procedure in which syndrome are paradoxical puborectalis contrac- pelvic floor muscles actively participate in the tion (PPC) and puborectalis hypertrophy (PH). process. Rectal distention evokes the desire to When PPC is a functional disorder, it is also defecate and induces relaxation of the anal known as spastic pelvic floor syndrome or pelvic sphincter. Under conducive circumstances, the outlet obstruction. In patients with PPC, the act of is completed by adoption of a structure of the puborectali muscle is normal suitable posture, contraction of the diaphragm but the puborectalis muscle cannot properly and abdominal muscles to increase the intraab- relax and contract.4 Therefore, the ideal treat- dominal pressure, and relaxation of the two stri- ment should aim at restoring the normal pub- ated muscle of the puborectalis and external anal orectalis function rather than at removing sphincter. Puborectalis relaxation allows widen- normal tissue.5 ing and lowering of the anorectal angle. Coordi- Jorge et al6 reported that the mean success nation between abdominal contraction and rate for biofeedback for was 68.5%, pelvic floor relaxation is crucial to this process attributable to paradoxical puborectalis syn- (Fig. 26.1). drome. Other nonsurgical methods, such as bot- The puborectalis muscle is the most impor- ulinum toxin injection and anal dilation, can tant component of the levator mechanism relat- also offer improvement to some patients with ing to continence and defecation. This muscle PPC who do not respond to biofeedback.7,8 originates from the inferior border of the pubis Another, often neglected cause of puborectalis and the superior fascia of the urogenital syndrome is PH. The etiology of PH is unclear. diaphragm, and slings around both sides of the The most common cause may be due to to exert a pull and create the anorectal inflammation around the puborectalis, which angle. If the puborectalis muscle cannot relax or causes puborectalis edema and stimulates even contracts during defecation, the anorectal hypertrophy. Gradually, the puborectalis loses its angle will not change or may even decrease, elasticity and cannot contract and relax func- defecation will be difficult, and constipation can tionally.9,10 The authors reviewed 200 cases of PH ensue.1,2 In 1964, Wasserman3 termed this syn- and found sepsis around the puborectalis in 15% drome “puborectalis syndrome,” which is char- to 30%.9 Other factors such as congenital trauma acterized by difficult and painful defecation and, and chronic diarrhea may also play a role in the occasionally, the inability to defecate for several development of PH. The structure of the pub- days. On the basis of pathologic findings that orectalis is abnormal among patients with PH. have shown marked hypertrophy of the muscle Successful treatment cannot rely on biofeedback fibers, this type of anorectal stricture was known and other conservative methods, but does due to spasmodic hypertrophy of the puborec- respond favorably to segmental excision of the talis muscle. The main causes of puborectalis puborectalis muscle.

247 248 Constipation

increased anal sphincter tension in most of these patients and the puborectalis is clearly palpable, thick and stiff with a sharp border. When queried, these patients do try to push; however, the puborectalis has limited movement. The length of the is generally more than 4cm and any attempt to force the examining finger through the anal canal causes more spasm and pain. There is a residue of dry and hard stool in the rectum even after defecation. generally confirms the functional length of the anal canal of more than 4cm, although the resting pressures are in the normal range from 5 to 8.6cm. The maximal squeeze pressures are generally 3 to 8cm, without a significant amount of puborectalis contraction. Thus, the ability of the puborectalis to contract Figure 26.1. Mechanism of the puborectalis muscle. Top: lateral view; is decreased in patients with PH. Although bottom: anteroposterior view. balloon expulsion test shows that most patients can expel the balloon, the time of expulsion is longer than that in nonconstipated individuals. Diagnosis and Differential Diagnosis Colonic transit time study can show either rectal of Puborectalis Hypertrophy retention or colonic inertia, or it can be normal. Puborectalis electromyography (EMG) shows Clinical Manifestation many fibrillation potentials at rest without significant increases in action potentials when The most common complaint of patients with the patient is asked to squeeze or push (Figs. PH is difficult defecation, including frequent 26.2 and 26.3). Single-fiber electromyography attempts, a sense of incomplete evacuation, (SFEMG) shows that the single-fiber conduction and prolonged straining. Approximately 50% of time (SFCT) is often longer than 3.4µsec and the these patients require 15 to 30 minutes, and fiber density increases.11–14 Cui et al12 studied 64 some require 60 minutes or more, to evacuate. patients with PH and found that 92.2% showed Although all patients desire to defecate once or abnormal EMG and 95.3% showed abnormal more every day, they are usually unsuccessful. SPEMG. The EMG and SPEMG differences Digital shows that there is between PPC and PH are reported in Table 26.1.

Figure 26.2. Electromyography (EMG) of the puborectalis muscle of patients with puborectalis hypertrophy (PH). A: EMG at rest. B: EMG during straining. Surgical Treatment of Puborectalis Hypertrophy 249

Figure 26.3. Anal manometry of PH; the final functional anal canal length is increased, and the anal canal pressures do not change between the rest and strain phases. The anorectal reflex is inhibited.

The most important examination of PH is defecography. The anorectal angle becomes acute paradoxically in most cases of PH. At rest, the mean anorectal angle is 91 ± 11 degrees, and Table 26.1. The EMG and the SFEMG difference(s) between PPC in most patients it is less than 90 degrees. During and PH defecation, the mean anorectal angle is 93 ± 16 = = PPC (n 38) PH (n 64) degrees and the angle is in fact less than 90 EMG degrees in more than half of these patients. Rest Little fibrillation Great fibrillation These angles see little change between rest and potential potential 9 Slight contraction Polyphasic motor Dominant in short defecation, unlike the anorectal angle of normal unit potential spike wave individuals, which can increase by more than 20 Exertion contraction High wave Low wave degrees during defecation. Furthermore, the amplitude amplitude anal length becomes longer rather than shorter Push Paradoxical No or slight electrical electrical during evacuation as shown by defecography. activity activity The most significant sign of PH in defecography SPEMG is the “shelf” sign, which can be noted in the SFCT 2.8µsec >3.4µsec lateral sitting position and is caused by the upper Fiber density Normal Increase(d) position of the anorectal junction without EMG, electromyography changing between rest and defecation (Fig. SPEMG, single fiber electromyography 26.4).9,10 This telltale sign can be noted in all PPC, paradoxical puborectalis contraction patients with PH but is not seen in other patients PH, puborectalis hypertrophy with constipation. During a 10- to 15-minute SFCT, single fiber conduction time evacuatory effort, little or none of the barium is 250 Constipation

Figure 26.4. The shelf sign. The top row shows the typical shelf sign preop- eratively at rest (left), squeeze (center), and defection (right); the barium retained in the rectum cannot be evac- uated. Postoperatively (bottom row), the anorectal angle is still 90 degrees at rest (left), while at straining (middle) and defecation (right) the anorectal angle is greater than 90 degrees and the barium can be evacuated. expelled.6,11,15 During videodefecography,16 the orectalis should be abandoned due to the poten- anorectal angle does not change or changes less tial for incontinence. However, in these authors’ than 3 degrees in patients with PH, while it can experience, PH is also a very important cause of change more than 3 degrees between rest and puborectalis syndrome. Ger et al14 studied 116 defecation in patients with PPC or other reasons patients with chronic constipation and found for constipation. Pathologic examination of the that the evacuation pressure by anorectal puborectalis demonstrates marked hypertrophy manometry (ARM) was divided into a normal of the skeletal muscle in patients with PH. relaxed pattern, an equivocal or nonrelaxed pattern, and a paradoxical contracted pattern. Some patients with the equivocal or nonrelaxing Differentiation Between Paradoxical pattern may have had PH. If PPC is the only Puborectalis Contraction and Puborectalis cause of puborectalis syndrome, then theoreti- Hypertrophy cally biofeedback should cure all patients. However, at most only 70% of patients with PPC Paradoxical puborectalis contraction is a very respond to biofeedback. In fact, more recent data common disorder and is thought to be the sole suggest success rates of approximately 55%.5 cause of puborectalis syndrome, especially since Therefore, PH is an important cause of puborec- biofeedback is successful in some patients with talis syndrome, although seldom recognized. PPC.17 Few series include patients with PH, and The differences between PPC and PH are sum- many surgeons believe that division of the pub- marized in Table 26.2.

Table 26.2. The differences between PPC and PH PH PPC Etiology Puborectalis organic abnormal Puborectalis functional abnormal Length of the anal canal More than 4cm Less than 4cm Evacuation pressure Not change or slightly decrease Increase paradoxical EMG and SFEMG See Table 26.1 See Table 26.1 Shelf sign Yes No Change of the anorectal angle in video defecography Less than 3 degrees More than 3 degrees Paradoxical contraction No Yes Biofeedback No response Respond mostly Pathology of puborectalis Hypertrophy Normal

PPC, paradoxical puborectalis contraction PH, puborectalis hypertrophy EMG, electromyography SFEMG, single fiber electromyography Surgical Treatment of Puborectalis Hypertrophy 251 Diagnostic Criteria of Puborectalis Anal Dilation Hypertrophy Anal dilation is indicated for those patients who 1. Difficult defecation, including frequent are unresponsive to conservative treatment. attempts at defecation, a sense of incomplete Maria et al8 treated 13 patients with puborectalis evacuation, and/or prolonged straining with syndrome with 10-minute daily progressive anal incomplete evacuation. dilations by insertion of three dilators sized 20, 2. Elongated anal canal confirmed by 23, and 27mm in diameter, from the smallest digital examination, anal manometry, and to the largest, for a 3-month period. Six months defecography. after completion of treatment, all patients reportedly had good clinical outcome and none 3. Anal canal resting pressure is normal or reported any incontinence. Spontaneous bowel slightly increased, and there is no signi- movement frequency increased from zero to six ficantly change during evacuation. per week and the need for laxative use decreased 4. Fibrillation potential is common at rest, while from 12 patients with a weekly mean of 4.6 to the action potential does not significantly two patients once per week. During straining, change when the patient squeezes or pushes; tone measured with anal manometry decreased µ SFCT is more than 3.4 sec. from 93 to 62mmHg 6 months after completion 5. No paradoxical contraction is found by of therapy, and the anorectal angle measured by digital anal examination, manometry, or defecography during strain increased from 95 to videodefecography. 110 degrees. The authors concluded that daily 6. “Shelf sign” can be found in all patients, progressive anal dilation should be considered and the anorectal angle changes less than 3 as the first and simplest therapeutic procedure degrees between rest and push during in patients with puborectalis hypertrophy. defecography. However, daily progressive anal dilation is time- 7. Does not respond to biofeedback. consuming and is not universally appealing to 8. PH can be found on pathologic examination. patients. Alternatively, after local anesthesia, a Pratt speculum can be inserted into the anus and 9. PPC has been excluded. gradually opened to its maximum aperture after which it is held in that position for 5 minutes. These authors have treated 100 patients with PH by this method since 1999 with an 80% improvement rate. There was decreased anal Treatment resting pressure and an increased anorectal angle; no incontinence was reported at a follow- Conservative Treatment up that ranged from 1 to 5 years. Patients with PH and mild symptoms of consti- pation should initially be given conservative Partial Resection of the treatment, which includes (1) a high-fiber diet of Puborectalis Muscle at least 15g per day and adequate water intake of 2000 to 3000mL per day; (2) physical exercise Indications (habit training is also very important for patients with PH); (3) bulk or lubricated laxa- 1. Meets diagnostic criteria of PH. tives, which can be given if evacuation is very difficult and painful, but stimulant laxatives 2. Defecation cannot be improved by conserva- should be avoided; and (4) puborectalis exer- tive methods and dilation. cises in the knee–chest position, with contrac- 3. An abscess around the puborectalis is found tion and relaxation of the puborectalis at least by intrarectal ultrasonography, computed 500 times per day to help recover the elasticity tomography (CT) scan, or magnetic reso- of the puborectalis. According to these authors’ nance imaging (MRI). experience, conservative treatment in approxi- 4. No colonic inertia or other abnormalities that mately 200 patients with PH has resulted in can cause outlet obstruction-type constipa- significant symptomatic relief in 50%. tion are present. 252 Constipation Contraindications

1. Findings of PPC. 2. Identification of one or more abnormalities that cause obstruction, constipation, or colonic inertia.

Surgical Procedure

Either sacral or lumbar anesthesia is adminis- tered prior to positioning the patient. The surgeon should stand on the patient’s left side. The patient is then placed in the prone jack-knife position with the buttocks retracted with adhe- sive straps, keeping the posterior median raphe in the midline. A low 3- to 5-cm midline incision is made from the posterior anal verge to the tip Figure 26.5. Surgical procedure for PH: an incision is made while the of the . A longer incision does not facili- patient is in the prone jackknife position (PH, puborectalis hypertrophy). tate superior exposure. The incision is subse- quently deepened by diathermy until the tip of the coccyx is exposed, as the coccyx is the land- mark of the superior border of the puborectalis following the procedure, all patients reportedly muscle. The surgeon’s left index finger is intro- had frequent discharge of gas, and within 7 days duced into the rectum and the puborectalis 90% of the patients were passing soft or formed muscle is elevated into the surgical field. The stools at least once daily. Defecography per- superior border of the puborectalis muscle lies formed 4 weeks after the procedure revealed a just beneath the tip of the coccyx, to which it flatter anorectal angle during evacuation than is attached. Curved clamps are used to separate that noted prior to surgery. The defecography the puborectalis muscle posteriorly and laterally. of two typical patients are shown in Figures Simultaneously, the finger in the rectum is used 26.9 and 26.10. At a median follow-up of 6 years to guard against enterotomy. The puborectalis is (range 1–18), 42 (61%) of patients can freely clamped laterally and then the intervening defecate whereas 19 (28%) still experience muscle is excised for a width of approximately some difficulty and require laxatives or 1.5cm. The remaining end of the muscle is have subsequent anal dilation. Six patients evac- ligated with 00 silk sutures or absorbable uate with significant difficultly and require sutures. After resection, a well-defined V-shaped the use of enemas for complete evacuation. defect should be palpable by the finger in the The two patients who evacuate less than once rectum. Any remaining fibers on the wall of the weekly had endorectal ultrasonographic rectum should be resected and not merely findings of perineal abscess. In these patients, a divided. The wound is irrigated and, if necessary, second division of the puborectalis was under- a small drain is inserted. Finally, the subcuta- taken. Three patients reported slight inconti- neous tissue and the skin are closed with inter- nence to gas and liquid while all patients were rupted sutures. The surgical treatment of PH is fully continent. illustrated in Figures 26.5 to 26.8. Wasserman3 proposed spasmodic hypertro- phy of the puborectalis muscle. He reported on four patients, three of whom underwent partial Results and Follow-Up resection of the puborectalis muscle with excel- lent results. Partial resection of the puborec- Between 1985 and 2003, 69 cases of PH talis muscles was advocated by Wallace and fulfilled the inclusion criteria outlined earlier in Madden,18 based on their series of 33 adults and this chapter and subsequently underwent partial 11 children. Kawano et al19 reported relief of division of the puborectalis muscle. The day symptoms in three of seven patients who under- Surgical Treatment of Puborectalis Hypertrophy 253

Figure 26.6. Surgical procedure for PH: dissection (PH, puborectalis hypertrophy).

Figure 26.7. Surgical procedure for PH: clamping the puborectalis Figure 26.8. Surgical procedure for PH: resection (PH, puborectalis muscle (PH, puborectalis hypertrophy). hypertrophy). 254 Constipation

Figure 26.9. Preoperative defeco- graphy (top) and postoperative defeco- graphy (bottom). went partial resection of the puborectalis sion is not as effective as partial resection, and muscle. However, in the series of Barnes et al,20 the rate of is higher after com- only two of nine patients who received complete plete puborectalis division. Liu et al21 studied 149 division of the puborectalis muscle obtained patients who underwent partial division of the relief, while seven had symptomatic improve- puborectalis muscle and found complete resolu- ment. This report suggests that complete divi- tion of symptoms and no incontinence in 134

Figure 26.10. Preoperative (top) defecography. Note the shelf sign at rest (left) and during attempted but unsuc- cessful evacuation (right). Postoperative defecography (bottom) shows normal anatomy at rest (left) and during suc- cessful evacuation (right). Surgical Treatment of Puborectalis Hypertrophy 255

Table 26.3. The results of division of the puborectalis muscle Success rate Reference Diagnosis Procedure nn% Wasserman (1964)3 Puborectalis syndrome Posterior partial resection 4 3 75 Wallace (1969)18 Puborectalis syndrome Posterior partial resection 44 33 75 Keighley (1984)24 Outlet syndrome Partial division 7 1 14 Barnes (1985)20 Chronic constipation Partial division 9 2 22 Kamm (1988)22 Chronic constipation Partial division 18 4 22 Kawano (1997)19 Puborectalis syndrome Partial resection 7 3 43 Yu (1990)23 Puborectalis syndrome Partial resection 18 15 83 Liu (2001)21 Puborectalis syndrome Partial resection 149 134 90 Xu (2002)25 Puborectalis hypertrophy Partial resection 29 28 97

(90%) patients. The results of division of than 1.5cm) is resected, the cut ends may re- the puborectalis muscle are summarized in adhese and cause stricture recurrence. Postoper- Table 26.3. ative balloon dilation of the rectum may prevent Two factors may explain the significant vari- adhesion recurrence. The authors treated two ability of the operative results. One is the diver- patients whose symptoms recurred owing to sity in the operative indications among the adhesions between the resected ends who subse- various series. For instance, Kamm et al22 quently underwent a second procedure. included megarectum as an indication for pub- orectalis division. Other series include patients who have had one or more concomitant causes Conclusion of outlet obstruction constipation. Puborectalis division is only valuable in patients with PH Constipation is a complex disorder, the under- without other concomitant causes of constipa- standing of which remains superficial. Partial tion. A second factor is the differing surgical resection of the puborectalis muscle only techniques among the surgeons. There are three releases the abnormal mechanism of defecation. methods for this procedure: posterior partial This procedure, therefore, should be restricted to resection; posterior division; and lateral, unilat- those patients who have definite evidence of eral, or bilateral resection. Division of the pub- outlet obstruction caused by hypertrophy of the orectalis alone may not allow complete muscle puborectalis muscle and who fail to respond to end retraction, as adhesions may develop and conservative therapy. It is also imperative to can cause symptom recurrence. For this reason, correct inappropriate bowel habits and diet prior the partial resection should extend from the pos- to surgery. terior rectal wall to the puborectalis muscle, Both PPC and PH are poorly understood con- dissecting both cut ends as widely as possible. ditions which require further investigation. Pub- At least a 1.5-cm width of muscle should be orectalis hypertrophy is a condition that causes resected. outlet obstruction constipation. Although it has Why does partial resection of the puborectalis some similarity with PPC, it is an organic disor- muscle fail? The reasons for failure may include der caused by hypertrophy of the puborectalis concomitant unrecognized anatomic outlet muscle due to inflammation, congenital struc- obstruction due to either intussusception or ture, trauma, or other etiologies. While PPC is a .The authors emphasize the importance functional disorder and the structure of the pub- of thorough preoperative physiologic evaluation orectalis is normal, it does respond to biofeed- and exclusion or successful treatment of all other back and botulinum toxin type-A injection, causes of constipation. Incompletely resected unlike PH. Only those patients who have definite adhesions or fibrous bands between the pub- evidence of outlet obstruction caused by hyper- orectalis muscles and rectal wall may result in a trophy of the puborectalis muscle, and who fail persistent stricture and continued symptoms. If to respond to conservative therapy, should an insufficient width of puborectalis muscle (less undergo division of the puborectalis muscle. 256 Constipation References 13. Fleshman JW, Dreznik Z, Cohen E, Fry RD, Kodner IJ. Balloon expulsion test facilitates diagnosis of pelvic floor outlet obstruction due to nonrelaxing puborec- 1. Bharucha AE. : don’t strain in talis muscle. Dis Colon Rectum 1992;35:1019–1025. vain! Am J Gastroenterol 1998;93:1019–1020. 14. Ger GC, Wexner SD, Jorge JM, Salanga VD. Anorectal 2. Schouten WR, Briel JW, Auwerda JJ, van Dam JH, manometry in the diagnosis of paradoxical puborec- Gosselink MJ, Ginai AZ, Hop WC. : fact or talis syndrome. Dis Colon Rectum 1993;36:816–825. fiction? 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