Probing Fistulae in the G . I . Tract

Fistulae are commonly encountered in general surgery. A fistula is an abnormal connection between two epithelial surfaces (figure 1). It can connect two hollow viscera together, or can connect a hollow viscus to the skin. In this way they can either be visceral and internal, or cutaneous and external. The connection between the surfaces is usually lined with granulation tissue. A sinus is a granulating track from a source of infection to the surface. Sinuses can develop into fistulae if inadequately treated. Copyright Royal Medical Society. All rights reserved. The copyright is retained by the author and the Royal Medical Society, except where explicitly otherwise stated. Scans have been produced by the Digital Imaging Unit at Edinburgh University Library. Res Medica is supported by the University of Edinburgh’s Journal Hosting Service url: http://journals.ed.ac.uk ISSN: 2051-7580 (Online) ISSN: ISSN 0482-3206 (Print) Res Medica is published by the Royal Medical Society, 5/5 Bristo Square, Edinburgh, EH8 9AL Res Medica, Summer 2003 : 16-19 doi:10.2218/resmedica.v0i0.1008 Probing Fistulae in the G.I. Tract Paul J Jenkins, Medical Student, University of Edinburgh Pradip K Datta, Consultant Surgeon, Caithness General Hospital Introduction Fistulae are commonly encountered in general surgery. A fistula is an abnormal connection be­ tween two epithelial surfaces (figure 1). It can connect two hollow viscera together, or can con­ nect a hollow viscus to the skin. In this way they can either be visceral and internal, or cutaneous and external. The connection between the sur­ faces is usually lined with granulation tissue. A sinus is a granulating track from a source of infection to the surface. Sinuses can develop into fistulae if inad­ equately treated. A fistula occurs as a complication of many different diseases, and from a variety of causes: Congenital tracheo-oesophageal fistula Acquired traumatic, e.g. rectovaginal fistula following labour neoplastic carcinoma inflammatory Crohn’s Disease infective diverticulitis fistula-in-ano iatrogenic surgical (post-op) radiation “A fistula is an abnormal con­ nection between two epithelial surfaces. It can connect two hollow viscera together, or can connect an hollow viscus to the skin. Gastro-intestinal fistulae are a surgical challenge.” Tracheo-Oesophaeeal Fistula Tracheo-oesophageal fistula is most commonly found with oesophageal atresia as a congenital abnormality. It results from incomplete separa­ tion of the larynx and trachea from primitive foregut. In 85% of cases the upper end of the oesophagus ends in a blind sac. The upper end of the lower portion of the oesophagus commu­ nicates with the trachea at the level of T4. In 50% of cases there has been maternal hydramnios, and in many cases there are other congenital mal­ formations. Babies with this condition suffer cyanosis, choking and feeding problems. Regurgitation from the blind oesophageal sac leads to aspiration and pneumonia. This condition is distinguished from obstruction by the presence of choking rather than vomiting. Confirmation of the diagnosis is obtained by the failure to pass a soft catheter. Opaque x-ray contrast medium injected through the catheter shows the sac. Emergency surgery is necessary within 24 hours EXTERNAL SURFACE EXTERNAL SURFACE OR OTHER HOLLOW VISCUS


Introduction
Fistulae are commonly encountered in general surgery.A fistula is an abnormal connection be tween two epithelial surfaces (figure 1).It can connect two hollow viscera together, or can con nect a hollow viscus to the skin.In this way they can either be visceral and internal, or cutaneous and external.The connection between the sur faces is usually lined with granulation tissue.
A sinus is a granulating track from a source of infection to the surface.Sinuses can develop into fistulae if inad equately treated.
A fistula occurs as a complication of many different diseases, and from a variety of causes: Congenital -tracheo-oesophageal fistula Acquired -traumatic, e.g.rectovaginal fistula following labour -neoplastic -carcinoma -inflammatory -Crohn's Disease -infective -diverticulitis -fistula-in-ano -iatrogenic -surgical (post-op) -radiation "A fistula is an abnormal con nection between two epithelial surfaces.It can connect two hollow viscera together, or can connect an hollow viscus to the skin.Gastro-intestinal fistulae are a surgical challenge."

Tracheo-Oesophaeeal Fistula
Tracheo-oesophageal fistula is most commonly found with oesophageal atresia as a congenital abnormality.It results from incomplete separa tion of the larynx and trachea from primitive foregut.In 85% of cases the upper end of the oesophagus ends in a blind sac.The upper end of the lower portion of the oesophagus commu nicates with the trachea at the level of T4.In 50% of cases there has been maternal hydramnios, and in many cases there are other congenital mal formations.
Babies with this condition suffer cyanosis, choking and feeding problems.Regurgitation from the blind oesophageal sac leads to aspiration and pneumonia.This condition is distinguished from obstruction by the presence of choking rather than vomiting.D iv erticu litis is a condition with recurrent in fection of diverticula in the wall of the colon (fig ure 2).These can form into pericolic abscesses.Rupture can occur into the peritoneal cavity.Al ternatively, adherence of the inflamed colon to adjacent organs may result in fistulae between the colon, bladder, small bowel, skin or vagina.
Fistulae occur in 2% of patients with diverticu lar disease, but are much more common in se vere disease.Fistulae are present in 20% of pa tients requiring operative treatment.A history of recurrent left iliac fossa pain, with a swinging fever and leukocytosis, along with symptoms and signs of fistulation should point to diverticulitis as the cause of fistulation.Vesicocolic fistulae occurring through diverticular disease are tend to result in pneumaturia, whereas though arising through neoplasia m ore often give rise to faecaluria.Treatment of diverticulitis is with flu ids and a n tib io tic s (M e tro n id a z o le and Gentamycin), with drainage of any intra-abdomi nal abscesses.
V esico co lic fistu la e (figures 3 & 4) are most commonly found in Crohn's disease, diverticu litis and colonic carcinoma.This results in in tractable cystitis and pneumaturia.Investigation is with MSU, barium enema, sigmoidoscopy, colonoscopy and cystoscopy.Intra-venous urog raphy should be carried out to rule out obstruc tion or fistulae higher up the urinary tract.
Treatment is by laparotomy, with excision of the affected bowel loop, anastomosis, and repair of the bladder wall.
F istu la -in -A n o results from the rupture of anal subcutaneous and submucosal abscesses.These abscesses arise within glands in the anal wall and spread along tissue planes.They are inadequately treated by incision and drainage alone.The ab scess may spread to the skin as a sinus with chronic discharge of pus.The sinus eventually will communicate with the anal canal higher up.Such fistulation occurs in 30% of abscess.An internal opening in the anal canal communicates with one or more openings in the perianal skin.The internal opening of the fistula may be felt on rectal examination.Fistulae are classified by their level and the structures of the anal canal they traverse.They are classified as subcutane ous, submucous, low anal, high anal, ano-rectal, and pelvirectal.Those entirely beneath the ano rectal ring can be treated by the insertion of a probe, and incising down onto the probe to lay open the fistula.The track is then laid open and left to heal by secondary intention.This has no effect on faecal continence as the external sphinc ter remains intact.In higher fistulae, the track can only be opened to the ano-rectal ring.A liga ture is thus passed through the upper track and left for 2 to 3 weeks for scar tissue to form.
Goodsall's Rule is useful if the location of the internal opening is not obvious." I f the external opening lies anterior to a line drawn transversely through the centre o f the anus, the tract passes radially through a straight line towards the in ternal opening.I f the external opening is p o ste rior to the line, the track curves in a horseshoe m anner to open into the midline p esterio rly".
Gastro-intestinal fistulae are a surgical challenge.The best outcome is obtained by a multi-disciplinary approach between the surgeon and the gastroenterologist with help from the radiologist for diagnosis and the dietician for overall man agement.

Matthew H Kaufman Professor of Anatomy, Honorary Librarian of the Royal Medical Society
Section of Anatomy, College of Biomedical and Clinical Laboratory Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD I thought that the members of the Society might be interested in learning about an "engraving" that hangs rather inauspiciously on one of the walls of the Society's Library in Bristo Place (fig ure 1).This item is of interest in several regards, but principally because no copy of it is available in the Reference Collection of the Royal Com mission on Ancient and Historical Monuments of Scotland (RCAHMS) in Bernard Terrace, Ed inburgh.A detailed analysis of its features, how ever, reveals that this image is in fact a photo graph of a very rare etching.The original is an anonym ous etching that measures 23.9 by 41.3cm including the fine border line around it.It is based on a drawing by the architect George Smith (located in the Daniel Wilson scrapbooks, Vol 1, p 78, in the Library of the National M useum s of Scotland).It is likely that

AbdomenG
astrojejunocolic fistulae m ost com m only arise from a carcinom a o f the stom ach eroding into the transverse colon or vice-versa.This results in severe diarrhoea, foul gas being discharged, and the vom iting o f form ed faeces.O ther sym p tom s o f gastric carcinom a are present such as anaem ia, asthenia and cachexia.The onset is extrem ely rapid.G a s tr o je ju n o c o lic fis tu la e are a ls o a c o m p licatio n o f p o ste rio r re tro co lic g a s tro jejunostom y, and may also occur from chronic anastom otic peptic ulceration.Anastom otic fistulae are usually cutaneous and present with bowel contents discharging through the wound several days post-operatively.P an creatic fistu lae (cutaneous) com m only occur after operation on the pancreas for traum a, a f te r W h ip p le 's o r a f te r p a n c re a tic necrostsectom y for severe acute pancreatitis and external drainage of a pseudocyst.The pancreas can enter a hypersecretory m ode and can secrete as much as 2 litre o f juice per day.Therefore, close attention m ust be paid to fluid balance in such patients.The patient should undergo an ultrasound scan to ensure there are no pancreatic fluid co llec tio n s, but o th erw ise should heal rapidly.If the pancreatic duct has been disrupted, then distal pancreatectomy should be undertaken.A ortoduodenal fistula is an uncom m on com plication o f abdom inal aortic aneurysm surgery.Patients com m only present m onths or years af ter operation w ith haem atem esis or m elaena.Urgent operation should be earned out to sepa rate the duodenum from the graft, close any holes in the duodenum and rem ove the graft.C rohn's Disease is a m ajor cause o f intestinal fistulae.It causes granulom atous transm ural in flam m ation follow ed by ax illo-inflam m atory bifem oral graft.A pproxim ately 25% o f patients develop fistulae at some point, the anus being a com m on area.C rohn's presents with chronic di arrhoea, abdom inal pain, weight loss and a spec trum o f extra-abdom inal sym ptom s.Fistulae are e x te r n a l o r in te rn a l.E x te rn a l c a n be enterocutaneous or perianal.Internal fistulae are enteroenteric, enterocolic, enterovaginal and enterovesical.C onfirm ation o f fistulae can be dem onstrated with contrast studies.A bscesses must be drained and enterocutanous fistula can result from C rohn's disease through the sam e m echanism .Treatm ent depends on the level of the fistula.Those with low output (<1 litre/day) will heal by secondary intention.Those with high output m ust be surgically repaired with excision o f the affected bowel loop.Steps m ust be taken

Figure 4 .
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