World J. Surg. 6, 539-548, 1982 Wo ma, of Stirgery

The Parasacral Sphincter-Splitting Approach to the Rectum

M. Allg6wer, M.D., M. Dtirig, M.D., A.v. Hochstetter, M.D., and A. Huber, M.D.

Department of Surgery, Kantonsspital, University of Basel, Switzerland

The parasacral, in most instances sphincter-splitting, ap- proach to the lower rectum has been used in 79 instances with no operative mortality; 36 cases of low rectal cancer were the subject of this paper. In UICC stages Ia and Ib (limited to mucosa and submucosa) and stage-II tumors, those of the T2N0 type (penetration of rectal musculature wall with no lymph node involvement), are good indications for this conservative surgery of very low rectal malignan- cies at any age; the stage of local lymph node invasion and the depth of rectal invasion require intraoperative histolog- ical evaluation. In more advanced tumor stages this ap- proach should be considered only if abdominoperineal amputation is categorically refused or if the patient is at very high risk (e.g., in very old patients). The parasacral operation is surprisingly well tolerated, provided the 2-3- hour procedure is carried out under optimal cardiorespira- tory supervision and care.

Although mostly forgotten, it is not surprising that some surgeons of the last century successfully avoided the then hazardous approach to rectal tumors by laparotomy and removed such tumors from below. Two basic procedures were advocated, one avoiding the various sphincters, the other delib- erately splitting the whole "continence organ." In 1875, Verneuil and Kocher [1, 2] described their direct approach to the rectum using a coccygec- tomy; and in 1885, Kraske [3] published his posteri- or rectotomy procedure advocating a partial resec- tion of the sacrum.

Deliberate splitting of the sphincters in the poste- rior midline to approach rectal tumors was first carried out by Cripps in 1876 [4]. It is noteworthy

Reprint requests: Prof. Martin Allg6wer, Vorsteher des Departmentes for Chirurgie, Universit/it Basel, Kantons- spital, CH-4031 Basel, Switzerland.

that of his 36 patients with no suturing of the divided sphincters, 23 regained continence! Other authors who confirmed the feasibility of a sphinc- ter-splitting approach with postoperative restora- tion of continence included Bevan in 1917 [5], David in 1943 [6], Larkin in 1959 [7], and Oh in 1972 [8]. The real impact for the increased use of this sphincter-splitting approach no doubt resulted from the work of York Mason, which he published extensively only in 1974 [9] after a long period of personal follow-up of a large patient group. Mason himself drew attention to previous work by the authors cited above, but pointed out that the work of Cripps had been forgotten and that his new endeavor met with great skepticism, indicating that surgical dogma dies hard.

York Mason explained the dependable restora- tion of continence, after splitting all sphincters as well as the puborectal sling in the posterior midline, by the fact that the vascular supply and the innerva- tion enter all parts of the levator and the external sphincters strictly from the lateral side.

The other link to the pathophysiological under- standing of continence was described by Winckler [10], Parks et al. [11], Stephens and Smith [12], and Lane and Parks [13]. As a result of these investiga- tions, it became clear that the defecation reflexes are largely mediated by the pelvic floor and depend very little on the presence of a rectal ampulla. In fact, the sigmoido-anal anastomosis is compatible with normal continence.

In collaboration with von Hochstetter, we found it necessary to study carefully the relationship of the rectum with what Mason [9] had termed the "perirectal fat"; the latter, in fact, is a highly complex structure containing numerous vessels and nerves which, previous to these studies, rendered a "bloodless" approach to the lower rectum from

0364-2313/82/0006-0539 $02.00 �9 1982 Soci6t6 Internationale de Chirurgie

540 World J. Surg. Vol. 6, No. 5, September 1982

Fig. 1. 1. Waldeyers' fascia 2. mesosigmoid 3. superior rectal artery and

vein 4. left lateral wing of the

rectum 5. middle rectal artery 6. plexus of pelvic veins 7. pelvic nerves 8. peritoneal pouch

(Douglas) 9. rectum

10. split sacrum

below rather difficult in our hands (Fig. 1). This "perirectal fat" is covered on its posterior side by Waldeyer's fascia and on its ventral side by Denon- villiers' fascia. It is entered orally by the superior rectal artery and lower down via the lateral wing of the rectum by the medial and lower rectal arteries and by the nervi pelvici (erigentes).

In addition to a precise analysis of the rectal envelope by fat and the Waldeyer's and Denonvil- liers' fascia, the topographic relationship of the pelvic floor muscles to the rectum and to its ner- vous supply seemed worthy of further study (Fig. 2). In our anatomical specimens, the course of these nerves could be ascertained to be on the inside of the levator muscle in its cranial portion and on the outside for the puborectal sling as well as for the various portions of the external sphincter, these nervi rectales inferiores being branches of the pu- dendal nerve.

Fascinated by the work of Mason and in view of the basically localized nature--and therefore good prognosis--of the early rectal cancer (U1CC stage Ia and Ib), we applied this method first in a few small tumors as well as in the case of a severely bleeding hemangiomatous malformation of the co- lorectum (Klippel-Trenaunay) with only the anal segment being intact. Fairly good continence result-

ed after transverso-anal anastomosis with no rectal ampulla left. Good results were also obtained in benign tumors, in complicated rectal-vaginal fistu- las, and particularly in pronounced rectal prolapse. Table 1 gives a survey of indications in which we have found the Mason approach useful.

This paper will only be concerned with the 36 cases of rectal cancer. The reader should appreciate that it was a learning period which has helped greatly to make us aware of indications and contra- indications. Anatomical studies (carried out by Huber in collaboration with yon Hochstetter) have taught us a much more careful intraoperative dis- section of the perirectal blood supply, resulting in a considerably reduced blood loss, in addition to making the operation much more anatomical.

Technique

The operative preparation of the patient is not different from that used for any colon resection or anterior resection making use of whole gut lavage and preoperative antibiotic prophylaxis.

Figure 3 shows the prone Heidelberg position. Emphasis is on a completely free abdominal wall for good pulmonary ventilation during the procedure,

M. Allg6wer et al.: Parasacral Sphincter-Splitting Approach 541

Fig. 2. 1. gluteus maximus muscle 2. sacrotuberous ligament (cut) 3. canalis of Alcock 4. pudendal vessels and nerve 5. ischiadic spine 6. sacrospinous ligament 7. inferior rectal artery, inferior rectal

nerve (cut) 8. external sphincter 9. pelvic floor (levator ani muscle)

10. inner, longitudinal fibers of levator ani muscle

11. longitudinal fibers of external muscle layer of rectum

12. raphe anococcygica 13. anococcygeal ligament 14. sphincter ani internus muscle 15. Waldeyer's fascia 16. lateral wing of the rectum

Table 1. Indication and operative mortality of the parasa- cral sphincter-splitting approach to the rectum.

Number of Diagnosis patients Operative mortality

Rectal carcinoma 36 0 Rectal myosarcoma 1 0 Adenoma 9 0 Rectal prolapse 23 0 High fistulas 5 0 Inflammatory stenosis 1 0 Klippel-Trenaunay 1 0 Reconstructions 3 0 Total 79 0

the weight being taken by the knees and pelvic ring. The left parasacral incision reaches from the

gluteus maximus to the anocutaneous transition, visualizing the inner rectal sphincter at the lower end (Fig. 4). The severing of the various portions of the external sphincter must be done between identi- fying ligatures in the posterior midline up to and including the strong puborectal sling (Fig. 5). The levator ani is severed in immediate proximity to its coccygeal and sacral insertion after again marking the various bundles by identifying sutures for easy reconstruction of the pelvic floor and the sphinc- ters.

The next step is that of the identification of Waldeyer 's fascia and the perirectal fat contained within. Then follows the exposure of the muscular wall of the rectum (Figs. 6, 7). The vessels entering the perirectal fat from the lateral side are succes- sively divided and the rectal ampulla thus exposed as extensively as possible. The rectoanal canal is then freed all around, separating it from the vaginal wall in the female and from the urethra and the prostate capsule in the male.

If the tumor is very small so that strictly local excision appears warranted (stage Ia UICC, tumor confined to mucosa and submucosa), the rectum is opened longitudinally, away from the tumor (Fig. 8). In all tumors exceeding stage Ia, segmental resection is advisable. Once a portion of the posteri- or rectal wall is exposed, and the rectoanal canal freed all around over a segment of 1-2 cm, it is helpful to sever the rectum (Figs. 9 and 10) at least 2 cm from the tumor. The rectum can thus be elevat- ed, and freeing the ventral side becomes easier. It is not uncommon to open Douglas' peritoneal pouch on the ventral side; this can even be helpful to mobilize the sigmoid in order to avoid tension on the suture line. Local and segmental resect ion must be carried out by removing the total rectal wall of the tumor-bearing area and its surroundings. In all cases of proven rectal malignancy, immediate fro- zen section to ascertain the depth of the tumor penetration is mandatory.

542 World J. Surg. Vol. 6, No. 5, September 1982

)

Fig. 3. Heidelberg position

Fig. 4. 1. sphincter ani externus muscle 2. puborectal sling 3. levator ani muscle 4. gluteus maximus muscle 5. coccyx

Fig. 5. 1. sphincter ani externus muscle 2. puborectal sling 3. levator ani muscle 4. gluteus maximus muscle

M. AIIg6wer et al.: Parasacral Sphincter-Splitting Approach 543

Fig. 6. 1. Waldeyer's fascia 2. lateral wing of rectum 3. sphincter ani externus muscle 4. levator ani muscle 5. rectum

The reconstruction of either a local wall excision or of a segmental resection is straightforward (Figs. 8, 10, l 1). The anterior wall will be closed by intraluminal Donati stitches with some resorbable synthetic suture material. The reconstruct ion of the posterior wall necessitates in most cases a T-shaped suture. It is carried out as a tangential suture engaging musculature and submucosa, and again a resorbable synthetic material is used.

Results

Table 1 gives an overview of 79 cases operated on by the "Mason approach ." It should be pointed out that no operative mortality resulted in this group of patients.

Fig. 7. I. "perirectal fat" 2. split Waldeyer's fascia 3. vessels to rectum 4. sacrospinous ligament

Table 2 gives the relationship of preoperat ive evaluation to intra- and postoperat ive findings. It is obvious that even stages Ia and Ib can be diagnosed with only a moderate degree of certainty on clinical grounds.

Table 3 indicates recurrences and when they occurred. All 9 recurrences were observed within the first 24 postoperat ive months. Of special inter- est is a patient with a cancer of the middle rectum UICC stage II (T2N0) treated by segmental resec-

544 World J. Surg. Vol. 6, No. 5, September 1982

Fig. 8. Local excision of tumor including rectal wall.

tion. This patient developed a small extrarectal recurrence with no direct relationship to the rectal wall. It manifested itself by a perirectal abscess some 8 months after the initial operation and was managed by local excision. One year later, a carci- noma of the lower sigmoid, which had not been diagnosed at the first hospitalization, made an ab- dominoperineal amputation necessary. Careful work-up of the amputation specimen revealed no evidence of local tumor, and the patient is now alive 7 years after the initial operation.

Table 4 gives an overview of all patients treated in our institution. Late mortality occurred almost exclusively in patients with tumor stages III and IV.

The 2 stage-IV patients operated on who categor- ically refused colostomy died after 3 and 6 months, respectively. At autopsy the patient who only sur- vived 3 months showed an extensive gastric carci- noma with liver metastasis and an intact rectal anastomosis with no evidence of local tumor recur- rence. The second patient who died after 6 months had widespread pelvic and peritoneal carcinosis; the anastomosed rectal wall, however, was free of tumor.

Temporary colostomy after the perineal resection was done only rarely; that is, 3 times prior to or simultaneous with the tumor resection and once secondarily on account of partial anastomotic breakdown. Of the 36 patients with resected carci- nomas, 8 developed a local abscess formation, most likely due to partial breakdown of the anastomosis. In no case did this lead to incontinence or perma- nent fistula.

Discussion

The relative benignity of the parasacral sphincter- splitting approach deserves mention. The opera- tion, carried out in the prone Heidelberg position lasts from 2 to 3 hours, but is surprisingly well tolerated by elderly debilitated patients and obvi- ously carries a much lower risk than the extensive laparotomy required for an anterior resection. It is noteworthy that we had no operative mortality in the 36 tumor patients nor in the remaining 43 cases of rectal operations dealt with by the Mason ap- proach, including 23 cases of rectal prolapse with fairly extensive segmental resections.

The crucial question is, at what tumor stage and at what distance from the anocutaneous border can and should the Mason sphincter-splitting parasacral operation be applied.

Clinically mobile rectal tumors which at opera- tion prove to be of the T1 type (limited to mucosa and submucosa) and T2 type (penetration of the rectal musculature) with no lymph node involve- ment appear ideally suited for this approach. This is particularly true if the tumor is situated so low that resection must be carried down to the anal crypts, that is, to the upper end of the anal canal. In such cases there is often not enough aboral segment left to make use of the stapler. This was particularly obvious in a case of rectal myosarcoma, where only 2 cm of the open anal canal could be preserved and anastomosed to the mobilized sigmoid. This patient has regained satisfactory continence except for very liquid stools. Such low tumors may be re-

M. Allg6wer et al.: Parasacral Sphincter-Splitting Approach 545

Fig. 9. 1. "perirectal fat" 2. split Waldeyer's fascia 3. Lateral wing of rectum 4. peritoneal pouch (Douglas) 5. rectum

moved either by local excision if their diameter is less than 2 cm, or by segmental resection if they are larger, with care being taken to remove all of the rectal wall at the tumor site. Our preliminary results appear to bear out the observations of Mason and also Madden [9, 14], whose long-term results with local procedures were at least as good as with rectal amputation in early cases. This is not surprising, considering the results obtained by Hochenegg [15], G6tze [161, Bacon [17] and d'Allaines [18]. Gall and Hermanek [19] have recently confirmed the im- proved prognosis following their surgical treatment of rectal cancer subsequent to a marked increase of sphincter-perserving operations in relatively low rectal tumors. It should be pointed out, however, that Gall and Hermanek again emphasized the clas-

sical 5-cm tumor-free rectal segment which would make every tumor lower than 8 cm from the anocu- taneous border unsuitable for conservative surgery, whereas the Mason approach can be used for tu- mors down to 2 cm from the anal canal (that is, 4-5 cm from the anocutaneous border in tumors less than 3 cm in diameter measured with the palpating finger which glides up the rectal wall). Anterior resection, however , remains the operation of choice in all rectal tumors that can hardly (if at all) be reached at rectal digital exploration.

The lateral spread of the tumor cannot always be appreciated during preoperat ive clinical investiga- tion and, therefore, intraoperative histology is para- mount. Because an NO stage in a T3 tumor (beyond the rectal wall) is very unlikely, amputation in such cases is advisable unless the patient is considered a very high risk or categorically refuses a permanent colostomy. This is even more true with a T4 tumor extending beyond the immediately adjacent "peri- rectal fa t ." Palliation, if not cure, in most T3 tumors and in all T4 tumors would appear better achieved with either amputation, transanal partial electrore- section, or simple loop colostomy.

The issue of whether a perineal segmental resec- tion in a T2NI tumor offers less chance of perma- nent cure than a more radical procedure remains unsettled. Any spread to the lymph nodes apparent- ly heralds a poor prognosis, regardless of surgical treatment. This would be even more true for any N4 lymph node involvement.

Temporary colostomy is not mandatory after perineal segmental resection and in fact, has only been carried out in 4 of a total of 36 surgically treated patients. It should, however , be carried out if the vascularity of the anastomotic segments is in doubt.

In conclusion, tumors confined to the rectal wall (UICC stage Ia, Ib as well as stage 1I) with no lymph node involvement and with their lower end being no closer than 2 cm to the anal crypts (about 4-5 cm above the anocutaneous border) can be treated by the parasacral sphincter-splitting ap- proach as described by Mason. The results in such cases appear to be at least as good as with mutilat- ing procedures, and this operation should not be denied to suitable patients.

R6sum6

L'abord du rectum par voie sacrale-- le plus sou- vent associ6 /~ une division de t o u s l e s sphincters anorec taux--a 6t6 pratiqu6 dans 79 malades sans mortalit6 opdratoire dont 36 malades avec des can- cers du rectum situds tr6s bas forment le sujet de cet expos6. Les stades UICC Ia/ib (tumeurs mu-

546 World J. Surg. Vol. 6, No. 5, September 1982

Fig. 10. Excision of tumor with rectal segment.

queuses et sousmuqueuses) et parmi les stades II les T2N0 (tumeurs pdndtrant la musculature rectale mais sans atteinte des ganglions lymphatiques lo- caux) peuvent ~tre consid6rds comme de bonnes indications ~ chaque fige, l 'analyse histologique intraop6ratoire 6tant de rigueur pour la ddcision ddfinitive lots de l 'operation. Pour les tumeurs de stades plus avanc6s la r6section parasacrale ne saurait Otre considerde que chez les malades refu- sant cat6goriquement la colostomie ou les malades constituant un grand risque op6ratoire, comme p.ex. ~t l'fige tr6s avanc6 et en 6tat g6ndrale rdduit. L'op6ration parasacrale, bien que durant de 2 ~t 3 heures, est 6tonnement bien toldrde ~t condition que le malade profite d 'une supervision cardiorespira- toire intraoperatoire optimale aussi bien pendant qu'apr6s l ' intervention.

References

Fig. 11. Anastomosis of the rectal stumps.

1. Verneuil, A.A., quoted by Tuttle, J.P.: A Treatise on Diseases of the Anus, Rectum and Pelvic Colon, 2nd edition. New York, Appleton, 1906

2. Kocher, T.: Die Exstirpatio recti nach vorheriger Excision des Steissbeines. Centralbl. Chir. 10:145, 1874

3. Kraske, P.: Zur Exstirpation hochsitzender Mast- darmkrebse. Verh. Dtsch. Ges. Chir. 14:464, 1885

4. Cripps, W.H.: Cancer of the Rectum. London, Churchill, 1880

5. Bevan, A.D.: Carcinoma of rectum--treatment by local excision. Surg. Clin. North Am. 1:1233, 1917

M. Allg6wer et al.: Parasacral Sphincter-Splitting Approach 547

Table 2. Relation of preoperative evaluation to intra- and postoperative findings.

Clinical assessment (Mason)

Postoperative staging UICC (1978)

N Ia Ib II III IV

I 15 7 5 2 1 II 14 9 1 4

III 6 1 3 IV 1 1 V (1)"

36 7 14 4 9

"Also included in Mason stage III, but with identified liver metastases.

Table 3. Recurrence of tumor (months after primary operation).

Months Stage Number of No pUICC patients 6 12 24 36 recurrence

Number of recurrences

Ia 7 7 0 Ib 14 1 1 12 2 II 4 1 2 1 3 III 9 2 2 5 4 IV 2 2 0

36 3 2 4 27 9"

"Of the 9 recurrences, 7 needed abdominoperineal amputation, 2 were suitable for more extensive local resection.

Table 4. Survival (months after operation) at end of 1981.

Alive (months) Dead (months)

Stage 36 or 36 or pUICC N 6 12 24 more 6 12 24 more

Ia 7 2 5 Ib 14 2 4 8 II 4 2 1 1 III 9 1 2 2 4 IV 2 2

36 2 5 5 15 2 2 1 4

6. David, V.C.: The management of polyps occurring in the rectum and colon. Surgery 14:387, t943

7. Larkin, M.A.: Transsphincteric removal of rectum tumors. Dis. Colon Rectum 2:446, 1959

8. Oh, C., Kark, A.E.: The transsphincteric approach to mid and low rectal villous adenoma: Anatomic basis of surgical treatment. Ann. Surg. 176:605, 1972

9. Mason, A.Y.: Transsphincteric surgery of the rec- tum. Prog. Surg. 13:66, 1974

10. Winckler, G.: Remarques sur la morphologie et l ' in- ervation du muscle releveur de l 'anus. Arch. Anat. Histol. Embryol. 41:77, 1958

11. Parks, A.G. , Porter, N.H. , Melzak, J.: Experimental study of the reflex mechanism controlling the mus- cles of the pelvic floor. Dis. Colon Rectum 5:407, 1962

12. Stephens, F .D. , Smith, E.D.: Ano-rectal Malforma- tions in Children. Chicago, Year Book, 1971

13. Lane, R., Parks, A.G.: Function of the anal sphinc- ters following colo-anal anastomosis. Br. J. Surg. 64:596, 1977

14. Madden, J .L.: Clinical evaluation of electrocoagula- tion in the treatment of cancer of rectum. Am. J. Surg. 122:347, 1971

15. Hochenegg, J.: Beitrfige zur Chirurgie des Rektums und der Bauchorgane. Wien. Klin. Wochenschr. 2:578, 1889

16. GOtze, O.: Die abdominosakrale Resektion des Mast- darmes mit Wiederherstellung der nattirlichen Kon- tinenz. Langenbecks Arch. Klin. Chir. 206:293, 1944

17. Bacon, H.E.: Cancer of the Colon, Rectum and Anal

548 World J. Surg. Vol. 6, No. 5, September 1982

Canal. Philadelphia, J.B. Lippincott, 1964 18. d'Allaines, F.: Die chirurgische Behandlung des Rek-

tumkarzinoms. Leipzig, Barth, 1956

19. Gall, F.P., Hermanek, P.: Kontinenzerhaltende Operationen beim Rectumcarcinom. Langenbecks Arch. Chir. 354:45, 1981