injuries to the anal sphincters

Annals of the Royal College of Surgeons of England (1988) vol. 70

Combined sphincter repair and postanal

repair for the treatment of complicated injuries to the anal sphincters GAVIN G P BROWNING FRCSEd Research Fellow MICHAEL M HENRY FRCS

ROGER W MOTSON MS FRCS Consultant Surgeon Colchester General Hospital, Colchester, Essex

Honorary Consultant St Mark's Hospital, London

Key words: ANUS; ELECIROMYOGRAPHY; FAECAI, INCONTINENCE; FIBRE DENSITY; POSTANAL REPAIR; SPHINC'T'ER REPAIR

Summary The management of seven patients with multiple injuries to the anal sphincter musculature and its nerve supply,from major pelvic trauma, anal fistula surgery, or obstetric trauma, was reviewed. All were either incontinent of solid stools or had defunctioning colostomies. Anal manometry was abnormal in all patients. Concentric needle electromyography (EMG) showed anterior division of the external sphincter in all the patients; five also had posterior division of both the external sphincter and puborectalis. EMG abnormalities were found in the lateral quadrants of these muscles, particularly the external sphincter. Single fibre needle EMG showed evidence of reinnervation in the external sphincter in -six patients, and in the puborectalis in two, indicating partial denervation of the muscles. Treatment was by anterior sphincter repair using an overlapping technique, combined with postanal repair; the repairs were protected by a defunctioning colostomy. When assessed 4-60 months (mean 17 months) after colostomy closure all seven patients were continent of solid and semi-formed stools, but had urgency of defaecation. None could control liquid stool orflatus. After complicated sphincter injuries planned surgical reconstruction, based on EMG assessment of the sphincter muscles, can restore acceptable continence. Introduction Any injury to the perineum which divides the external anal sphincter and puborectalis musles results in faecal incontinence (1). In most cases the sphincter damage is uncomplicated, and comprises division of the muscles at a single site in the sphincter ring (1-5). Delayed sphincter repair using an overlapping technique (1) restores continence in approximately 70% of such patients, and improves function in a further 10% (1-7). The treatment of more complicated injuries to the external sphincter and puborectalis is more difficult (4,7). We report the management of seven patients with division of the Correspondence to: Mr R W Motson MS FRCS, Colchester General Hospital, Turner Road, Colchester, Essex C04 5JL

muscles at one or more sites, combined with injury to their supply. Electromyography was used to define the extent of the damage to the muscles and nerves, and to assess function in the remaining muscle. Treatment was by combined sphincter repair (1) and postanal repair (8). nerve

Patients and methods Table I lists details of the seven patients; their mean age was 30 years (range 14-51 years). The primary sphincter injuries were due to crushed pelves from road traffic accidents (4), surgery for anal fistula (1), and obstetric tears following prolonged labour (2). All the patients had undergone operative procedures for secondary anal fistula, and five previous sphincter repairs had been performed unsuccessfully. The four patients with colostomies had experienced uncontrolled discharge of mucus from the anus for 1-11 years (mean 4 years); the three patients without colostomies had been incontinent of formed stools for 6-16 years (mean 11.7 years). The time to presentation for repair ranged from 1-16 years (mean 7.4 years). On examination (Table I) all seven patients had a palpable defect in the anterior quadrant of the external sphincter, and three had a palpable defect in the posterior quadrant of the muscle. Five patients had excessive perianal scarring posteriorly, associated with extensive induration palpable in the posterior quadrant of the puborectalis. All the patients had signs suggesting partial denervation of the external sphincter and pelvic floor musculature (8,9), and all had abnormal clinical anorectal angulation (8). ANAL MANOMETRY

Anal canal pressures were measured in 6 patients using standard manometric techniques (9). Anal canal length was 0-2.5 cm, mean 1.4 cm (normal range 3.54-.5 cm, mean 4.0 cm); maximum resting pressure was 0-50 cmH2, mean 22 cmH20 (normal range 60-100 cmH20, mean 80 cmH20; and maximum voluntary contraction

Treatment of complicated injuries to the anal sphincters

325

TABLE I Clinical details in seven patients with multiple injuries to the anal sphincter musculature and its nerve supply

Physical signs Sex/age Injuries and previous surgey

at

_________________________________ Time to Clinical Palpation Palpation presentation anorectal puborectalis external anal for repair Perianal Perineal Anal angle muscle (yrs) scarring descent reflexes sphincter muscle

Patient

injury (yrs)

1

F14

RTA-crushed pelvis, anorectal laceration Colostomy, drainage pelvic abscess Lay open anal fistula x 2

3

Anterior Posterior L lateral

-

R+ L-

Posterior Anterior defect Posterior induration induration

Abnormal

2

F19

1

Anterior Posterior

+

RL-

Anterior/posterior

Posterior induration defects Posterior induration

Abnormal

3

F 13

1

Anterior Posterior R lateral

-

RL+

Posterior Anterior defect Posterior induration induration

Abnormal

4

M37

14

Anterior Posterior

+

RL-

Anterior/posterior Posterior induration defects Posterior induration ? defect

Abnormal

5

F15

11

Anterior Posterior

-

R+ L-

6

F28

6

Anterior R lateral

+

RL-

Abnormal Anterior/posterior Posterior induration defects Posterior induration Lengthened Abnormal Anterior defect

7

F33

RTA-crushed pelvis, perineal laceration Colostomy, lay open anal fistula X3 RTA-crushed pelvis, anorectal laceration Colostomy; SR, lay open anal fistula x 6 RTA-crushed pelvis, anorectal laceration Colostomy, lay open anal fistula X 2; colostomy closed 1 year later Lay open anal fistula X4 SR x 3; colostomy, lay open anal fistula x 3 Obstetric tears x 2, prolonged labour Lay open anal fistula X6 Obstetric tear, prolonged labour SR; lay open anal fistula x 2

16

Anterior

+

RL-

Anterior defect

Lengthened Abnormal

RTA=road traffic accident, SR=sphincter repair R= right, L= left; + = present,-= absent

pressure was 10-30 cmH2O, mean 13 cmH2O (normal range 120-250 cmH20, mean 160 cmH20).

(EMG) (Tables II and III) Concentric needle EMG was used to record conventional EMG activity in the external sphincter and puborectalis (9,10). The responses of the muscles to voluntary contraction, coughing and straining, were displayed and recorded on Medelecg MS6 EMG apparatus. The amplitudes of the recorded compound muscle action potentials were compared to the resting activity within the muscles. Both muscles were studied at several sites to define areas of functioning muscle and identify sites of muscle injury (sphincter mapping). A single fibre needle EMG technique was used to measure the muscle fibre density in the external sphincter and puborectalis (9,10). A raised fibre density indicates reinnervation in the muscles which may occur following partial denervation ELECTROMYOGRAPHY

(9-11). External sphincter On concentric needle EMG (Table II) all seven patients had division of the external sphincter in the anterior quadrant; five also had division of the muscle in the posterior quadrant. Active muscle was identified in both lateral quadrants in six patients. Four had abnormal EMG responses to voluntary contraction,

coughing and straining (9,10) (Table II). The separation of the muscle ends measured 3-5 cm anteriorly, and 2-3 cm posteriorly. On single fibre needle EMG six patients had a raised muscle fibre density (range 1.5-2.3, mean 2.03) (Table III); normal values: under 65 years 1.5±0.16 (SD) (9,10), under 30 years 1.37±0.09 (11).

Puborectalis Five patients had division of the puborectalis in the posterior quadrant; the separation of the muscle ends was indistinct. Active muscle was identified in both lateral quadrants in four patients; two had significant EMG abnormalities (9,10) (Table II). The muscle fibre density was raised in two patients (range 1.9-2.0, mean 1.95). SURGICAL RECONSTRUCTION

Sphincter repair and postanal repair were combined in one operation in five patients and staged one month apart in two. A defunctioning colostomy was performed in the three patients without a stoma. The anterior defect in the external spincter was treated by overlapping

sphincter repair (1,4). Conventional postanal repair (8,12) was added in patients without posterior injuries (patients 6, 7). In patients with posterior injuries (patients 1-5) the technique was modified as follows. Through a posterior circumanal incision the attachments

326

G G P Browning, R W Motson and M M Henry

TABLE ii Results of concentric needle electromyography of the external sphincter and puborectalis muscles Puborectalis

External anal sphincter

Patient

No EMG activity No EMG

No EMG activity No EMG

activity

activity

3#

No EMG

No EMG activity

4

activity NoEMG

1

2

5§

No EMG

NoEMG activity No EMG

activity

activity

611

No EMG activity No EMG

activity

7$1

activity

Right lateral quadrant.

Left lateral quadrant

*R 450 VC TT

R 400 VC TT C jj S 4 R