ARTICLES AND PUBLICATIONS
A new modification of Limberg flap for correction of severe anal stenosis
27th September, 2019
Dr. Ajitkumar S. Borkar, M.Ch. Plastic Surgery, Consultant Plastic Surgeon, S.L. Raheja / Fortis Hospital
Dr. Ulhas Y. Kulkarni, M.S. General Surgery, Consultant Colo-Rectal Surgeon, S.L. Raheja / Fortis Hospital
Indebted to Miss Priyanka Borkar for technical assistance and artwork creation.
This case presents two new concepts. Firstly, a new modification of Limberg flap is introduced where the flap is raised by extending the long axis of the rhombic defect. It is particularly useful for correction of contracture with the vector of release lying along the short axis. Secondly, we are introducing a novel method for surgical treatment of moderate or severe anal stenosis. This flap brings in ample amount of skin with excellent blood supply and mobility with least amount of tension at the suture line. It also allows excision of the cicatrix and can avoid internal sphincterotomy. Donor site closure scar does not add to the vector of contracture.
Limberg flap , Rhombic flap , Anal stenosis , Anoplasty
Potential method of choice in surgical treatment for severe anal stenosis.
Traditionally a Limberg flap is used to cover a rhombic shaped defect by making use of adjacent skin laxity at right angle to the short axis of defect . We are introducing a modification where the skin laxity at right angle to the long axis is utilized . This in effect rotates the rhombic through 90 degrees so that the axes get interchanged , the difference in their lengths providing additional release along the direction of the short axis ( fig. 1,2 ) . This modification makes the flap particularly suitable for contractures where you expect more release later because of the gradual stretching of underlying tissue like muscle or ligament .
Anal stenosis provides a perfect example of such a contracture where you can preserve the tight sphincteric muscle during the contracture release and stretch it later with dilatation . Surgical intervention in the form of anoplasty , internal sphincterotomy or both is advocated for moderate or severe grade anal stenosis . Sphincter preservation is advisable as sphincterotomy can result in anal incontinence . Most of the anoplasty methods e.g. house flap, diamond flap , V-Y plasty etc. are dependent on and limited by subcutaneous tissue for mobility and blood supply . Our modification of Limberg flap maintains a skin pedicle which is superior in both. It provides ample healthy skin without tension at the suture lines thus avoiding wound dehiscence and providing for future stretching of the sphincter . It is easy to learn and execute. We suggest it as a mainstay of surgical treatment for anal stenosis .
A 44 year old male presented with complaints of painful defaecation , hard stools , recurrent constipation and bleeding while passing stools . The symptoms developed after haemorrhoidectomy which he had undergone 3 years back . On examination he was found to have a very tight anal opening which did not allow digital examination . Under anaesthesia with relief from anal spasm , still it was not possible to do a digital examination . Anal opening was dilated with Hagar’s dilators till a paediatric size proctoscope could be introduced (fig. 3 ) . It revealed a severe diffuse tubular anal canal stenosis extending above the dentate line . Patient was planned for anoplasty with or without internal sphincterotomy .
Patient was put in a lithotomy position . Anal region and perineum were prepared and draped . Incisions were marked along the longitudinal axis of anal canal at 3 o’clock and 9 o’clock positions . They extended from healthy anoderm to about 1 cm. above the dentate line . The circumferential contracture was released carefully from distal to proximal till supple base was reached (fig.4) . The sphincteric muscle was found to be quite pliable and was left alone . The adequacy of the release was confirmed by easy passage of adult size proctoscope .
The release of contracture left a rhombic defect ABCD with the long axis AC lying along the longitudinal axis of anal canal . The long axis AC was extended upto E so that CE equaled any side of the rhombic . A line EF was drawn parallel and equal in length to BC (fig. 1,5 ). A rhombic flap BCEF was raised and inset in the defect so that point F and C , point E and D were approximated and the donor defect was closed primarily (fig. 2,6). The release of anal stenosis was reconfirmed with the easy passage of adult size proctoscope .
Postoperatively patient was given laxatives and stool softeners . Sutures were removed after two weeks . Anal diameter was confirmed every week with the passage of adult size proctoscope for 6 weeks and then twice a month for six months ( fig. 7) . Patient did not suffer from either constipation or anal incontinence .
Limberg flap was first described by Prof. A. A. Limberg of Leningrad in 1928 . It was introduced in English in 1963 ( 1 ) . A classic Limberg flap involves a rhombic transposition flap with angles of 60 degrees and 120 degrees and sides of equal length . It is planned by extending the short axis of the rhombic defect it is meant to cover . The variations of Limberg flap by Dufourmentel or Webster are also designed near the short axis of the defect and all of them use the laxity along the long axis to close the donor defect primarily ( 2,3 ) . If the vector of contracture were to lie along short axis of the defect , then the scar of donor site closure in these flaps would actually add on to the tendency to contract as in anal stenosis .
The modification of Limberg flap that we suggest is planned along the long axis of the defect which is extended equal to a side of the rhombic defect . A line parallel to side of defect is dropped from the end , again equal in length . It gives a transposition flap with sides equal to the sides of defect but with an obtuse angle 150 degrees and an acute angle 30 degrees for a classic Limberg defect ( 120 and 60 degrees ) . This flap uses the laxity along the short axis of the defect for primary closure , the scar of donor site closure being at right angle to the vector of contracture in anal stenosis . In effect this flap brings in a lot of skin for the contracture release .
Anal stenosis is a rare , incapacitating condition . 90 % of anal stenosis follow overzealous haemorrhoidectomy ( 4 ) . It was more common after Whitehead haemorrhoidectomy as compared to Milligan-Morgan or Stapled rectal mucosectomy ( 5 ) . Patient presents with complaints of painful defaecation , bleeding , constipation and narrow string like stools . Examination under anaesthesia eliminates the ‘ functional ‘ stenosis caused by sphincteric spasm and reveals ‘ anatomic ‘ or ‘ cicatricial ‘ stenosis . It is then graded as per Milson & Mazier classification ( 6 ) as follows –
Mild : Digital examination possible
Moderate : Prior mechanical dilatation required for digital examination
Severe : Digital rectal examination is not possible
The best treatment for post-surgical anal stenosis is prevention . Mild stenosis is managed with stool softeners , fiber supplements and dilatations . Moderate and severe stenosis require surgical intervention , either internal sphincterotomy or anoplasty or both . Various methods of anoplasty have been described using anal mucosa or anoderm like mucosal advancement flaps , Y-V plasty , V-Y plasty , U-flap , C-flap , House flap , Diamond flap , rhomboid advancement flap ( 7 , 8 ) . Almost all of these flaps are dependent on the limited mobility and vascularity provided by subcutaneous base. It causes tension , necrosis and dehiscence at suture line with resultant recurrence of stenosis .
A Limberg flap has certain distinct advantages –
It is easy to learn and execute
It brings pliant , healthy and highly vascular skin into defect
Donor site laxity is used to avoid tension at the suture line where it matters
Less chances of suture line dehiscence
Less morbidity and hospital stay
It can be used bilaterally
The modification we have suggested by raising the flap along the long axis of the rhombic defect has additional advantages –
It brings substantial additional skin along the direction of contracture release
It allows for future stretching of tight sphincter with dilatation , thus giving the option of avoiding sphincterotomy and possible anal incontinence
The donor site scar does not add on to the vector of contracture
We strongly recommend it as a primary method of choice for moderate or severe post-surgical anal stenosis . In short , this modification of Limberg flap is ideal for contractures released along the short axis of the rhombic defect where you expect further lengthening in future of the tight base formed by tissues like muscle , tendon , ligament or capsule .
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