6 The radiological management of gastrointestinal strictures and other obstructive lesions ALANGRUNDY

For many decades oesophageal stenoses have been the most easily accessible lesions for treatment by forceful dilation in preference to surgery. Dilation of benign oesophageal stenoses by mechanical means has become standard practice, while the cause is controlled by medical means with only occasional resort to surgery; and even the presence of a hiatus hernia or complications such as oesophageal ulceration should not contraindicate a trial of dilation therapy (Benedict, 1966). The history of bougienage dates back hundreds of years (Earlam and Cunha-Melo, 1981). Dilation was carried out in the past by the use of whalebone bougies and other instruments passed blindly perorally to deal with strictures of unknown cause, with a surprisingly low incidence of complications. Traditional treatment with unguided, transorally placed, soft mercury-weighted or rigid metal dilators is now being replaced by endoscopic or radiologically guided dilation with balloon catheters or the newer flexible bougie dilators. Dilation of enteric strictures has become established to the extent that gastroenterologists have adopted it and manufacturers have developed instruments specifically intended for endoscopists as well as radiologists (McLean and Meranze, 1989). The introduction of the balloon angioplasty catheter by Gruntzig in 1974 has been followed by the development of similar balloon dilation catheters for use in other sites. Although forceful dilation of achalasia of the oesophagus has been carried out using bags or balloons inflated with air or water for several decades, these systems have not had the flexibility for use in other lesions of the gastrointestinal tract that is now available with the new dilation catheters. It is just over a decade since the first report of balloon dilation of oesophageal strictures appeared (London et al, 1981), in comparison with conventional bougienage which has been in use for far longer. For lesions distal to the oesophagus, surgery has traditionally been the only method of treatment available, and the operative mortality, particularly in the elderly, may have precluded this form of treatment for some patients (McLean et al, 1987). Techniques of balloon dilation initially 319

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applied to oesophageal lesions have now been extended to other parts of the gastrointestinal tract-to the management of surgical anastomoses (de Lange and Shaffer, 1988; Solt and Papp, 1988; Whitworth et al, 1988; Aston et al, 1989; Grundy et al, 1990), fistulae, Crohn’s disease (AlexanderWilliams et al, 1986; Linares et al, 1988), the management of malignant disease (Nobrega, 1989) and to assist the insertion of palliative tubes (Blundell and Burhenne, 1984; Chisholm et al, 1986; Gallinger et al, 1989).

CATHETERS

AVAILABLE

Balloon dilation catheters are now available in a variety of different lengths and diameters, and of different materials; some of these catheters may be passed through the working channel of an endoscope. The Rigiflex TTS dilator (Key Med Southend on Sea, England) may be passed through the 2.8-mm working channel of an endoscope, and is available in sizes up to a maximum inflated balloon diameter of 18mm. The Lunderquist-Owman oesophageal dilation kit (William Cook Europe Ltd, Letchworth, England) and the Microvasive Rigiflex soft tip dilator (Key Med) can be inserted over a guide wire under radiological guidance (Owman and Lunderquist, 1982). The limiting factor in the use of bougies is the size that can be passed through the pharynx and upper oesophagus, whereas the limiting factor with balloons is the size of balloon currently available (Kollath et al, 1984).

ENDOSCOPIC

OR RADIOLOGICAL

GUIDANCE?

Endoscopic and radiological methods of catheter placement have their own advantages and disadvantages (McLean and Meranze, 1989). Endoscopy allows the operator a direct view of the mucosa at the site of a narrowing and allows biopsies to be taken. With a tight stenosis, however, the endoscopist may not have a view distal to the stricture, particularly when confronted by a tight or tortuous lesion, and passage of a guide wire through the lesion may in fact be blind. Fluoroscopic guidance following the administration of contrast medium, although not allowing biopsy, enables the operator to gauge accurately the length and configuration of the stricture, and to visualize the distal side of a lesion and the state of the more distal bowel. The development of imaging-guided brush biopsy techniques (J. P. Virjee, personal communication) may enable the radiologist to obtain satisfactory cytological samples prior to balloon dilation. Tortuous strictures may be more easily negotiated by the use of a radiologically guided steerable catheter system, or by using various preformed curved angiographic catheters and guide wires (Figure 1). Contrast medium injected through the catheter allows visualization of tortuous lesions. If resistance is felt during passage of a guide wire, a catheter can be advanced over the guide to the level of the resistance and injection of contrast medium will further define the anatomy of the stricture (McLean et al, 1987).

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Figure 1. Eccentrically sited anastomotic stricture in a patient who had undergone oesophagectomy for carcinoma of the oesophagus. An endoscopic attempt at dilation had been unsuccessful due to inability to find the eccentrically sited stoma. A steerable catheter system was used in order to pass the guide wire through the anastomosis, followed by satisfactory balloon dilation.

In general, water-soluble contrast medium is used to outline the stricture and the distal bowel, but if the patient is at risk from aspiration, a dilute barium suspension may be used instead of a conventional hypertonic watersoluble contrast agent; alternatively one of the less irritant non-ionic contrast media may be appropriate. Complete obstruction to the flow of radiological contrast medium at the site of a stricture does not preclude successful passage of a guide wire (McLean et al, 1987). The initial intubation of a stricture and placement of a guide wire is frequently the most technically demanding part of the procedure (McLean et al, 1987). Malignant strictures or those associated with ulceration must be cannulated with great care because of the risk of perforating the surrounding friable tissues (McLean et al, 1987). Oral passage of the catheter is usually employed. Some authors prefer to use a nasal route (Maynar et al, 1988), although patients tolerate oral passage of guide wires and catheters far better than nasal passage (Cohen et al, 1988). At St George’s Hospital radiological placement of dilation catheters is generally used, but recently a combined endoscopic and radiological technique has been adopted for dilation of postsurgical gastroenteric stenoses

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when radiological guidance alone has failed. A paediatric colonoscope has been used to reach stenoses in the jejunum, which would have been out of reach of a conventional gastroscope (Nealon et al, 1989). Inflation of the catheter once in position can be carried out either under direct endoscopic vision or under fluoroscopy. Water or dilute contrast medium, which is incompressible, is preferable to the use of air inflation. The pressure generated can be measured with a pressure gauge. This is mainly done to maintain the pressure below the level that would rupture the low-compliance balloon (Tytgat, 1989). The endoscopist may have a good view of the balloon distension although the waisting may be underestimated, resulting in inadequate dilation. Fluoroscopic control of dilation using dilute contrast medium allows more exact control of the degree of dilation. The balloon profile is easier to assess. The indentation of the balloon by the stricture not only confirms the position of the balloon but also gives a visual assessment of the success of dilation (Cox et al, 1988). Disappearance of the waisting signifies that the lesion has been dilated successfully, and prolongation of the procedure time may not be necessary (Griffin et al, 1989). Eccentric positioning of the balloon prior to inflation may cause it to migrate either cranially or caudally away from the stricture during dilation (Dawson et al, 1984), and keeping a balloon in a tortuous stricture occasionally can be difficult (Tytgat, 1989). This is a particular problem with short strictures, and may be difficult to appreciate with endoscopic control alone. Prior to radiologically guided balloon dilation without endoscopic guidance, contrast studies are needed to visualize the lesion to be dilated. This allows the operator to assessthe tortuosity and length of a stricture and the diameter of the lumen. Giving a marshmallow bolus with a mouthful of barium is of value to assess the true state of a stricture (Grundy and Belli, 1988). Patients who are to undergo balloon dilation should be fasted, and it may be necessary to perform a gastric or oesophageal wash-out in patients with achalasia or in patients who have pyloric obstruction or obstruction secondary to surgical procedures on the stomach for morbid obesity. This will reduce the likelihood of aspiration from the oesophagus into the larynx and trachea. It has been shown that balloon dilation of the oesophagus produces a transient bacteraemia and it is probably advisable for patients at risk from endocarditis to have antibiotic cover for the procedure (Hansen et al, 1989). Technique of radiologically

guided dilation

The technique used for peroral radiologically guided balloon placement is carried out under sedation with intravenous diazepam. Intravenous pethidine is used occasionally if patients experience undue discomfort during the procedure. The oropharynx is anaesthetized with a topical aerosol preparation of lignocaine. A small-bore nasogastric tube is passed across the stricture followed by the placement of a guide wire. The balloon catheter is then passed over the guide wire to lie across the strictured segment. Radiopaque markers at the proximal and distal margins of the balloon help in

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positioning the uninflated balloon at fluoroscopy. In some instances of relatively straight strictures, the author has used the soft, blunt-ended Lunderquist-Owman catheter without the initial passage of a guide wire. If a combined endoscopic-radiological method is used, the endoscope is advanced up to the proximal aspect of the stricture and the guide wire passed through the working channel of the endoscope. Under fluoroscopicguidance, the wire can be advanced as far as possible through the stricture and into the distal bowel. The endoscope is removed and a balloon catheter then advanced over the guide wire through the stricture. If through-the-scope catheters are used, these can be advanced over the guide wire through the working channel of the endoscope leaving the endoscope in position proximal to the stricture. The balloon is inflated under fluoroscopic control using a 50% dilution of water-soluble contrast medium (Conray 280, May & Baker Ltd). Even if a through-the-endoscope technique is used, fluoroscopic control of balloon inflation is an advantage (Figure 2). It is the practice at St George’s Hospital to inflate the balloon for 30 seconds, deflate the balloon and reinflate two or three times until the waisting disappears. When the waisting has disappeared, further dilation is probably unnecessary (Griffin et al, 1989). If the patient feels undue discomfort during dilation the balloon inflation is released and repeated after a few minutes’ rest. The ability of the patient to respond to undue discomfort may prevent the development of complications such as mucosal tears or perforation. Mild to moderate chest pain has been

Figure 2. Very tight midoesophageal stricture due to radiation fibrosis. The waisting of the balloon at the site of stricture could never be eliminated and this could not have been assessed by an endoscopic view alone. a

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reported in 75% of patients and can be controlled with intravenous analgesia (Dawson et al, 1984). If the stricture is too tight to allow the passage of the balloon catheter, initial dilation with a 6-mm or 8-mm angioplasty catheter may allow the subsequent placement of the dilation catheter (Gotberg et al, 1982). Some strictures may be so tough that the waisting will not completely disappear. In the author’s practice the Rigiflex catheter has been found to dilate tough strictures more satisfactorily than the Lunderquist-Owman catheter. Some strictures are so rigid that they resist maximum dilation pressure (Tytgat, 1989). Should a balloon rupture, the design ensures that it does so through a safe longitudinal tear rather than a damaging transverse ‘blow-out’ (Cox et al, 1986). A postprocedural chest radiograph is taken after 2-3 hours. This serves as a baseline; and evidence of mediastinal emphysema, free air under the diaphragm, a pneumothorax or pleural effusion should be sought. If the chest radiograph is normal the patient is allowed to eat and drink. The author has not performed routine postdilation contrast studies in these patients, Use of the smooth muscle relaxant hyoscine in a dose of 20mg intravenously was found to be useful in a recent case to help relax the oesophagogastric junction in a patient with achalasia. A little bleeding at the time of dilation frequently occurs and is manifested by blood on the catheter on withdrawal (Grundy and Belli, 1988). Endoscopic examination after dilation will show slight bleeding in about twothirds of cases (Gallinger et al, 1989), and when endoscopy has been performed on the next day, no visible damage to the oesophageal mucosa has been seen (Gotberg et al, 1982). BALLOON

VERSUS BOUGIE

There are few studies directly comparing the effectiveness of bougies with balloon dilation. Cox et al (1988) carried out a randomized trial of balloon versus bougie dilation. Bougienage was performed with a Celestin dilator followed by Eder-Peustow olives, whereas the balloon dilation was performed with a Rigiflex oesophageal balloon dilator. There was a small but clear difference in the effectiveness of the two techniques: the balloon group had more dysphagia and a greater degree of narrowing of strictures at the end of 5 months. Shemesh and Czerniak (1990) have also reported that Savary-Gilliard dilators were slightly more effective and easier to use than balloons in two groups of patients treated by one or other method. In the author’s experience, patients who had been treated by balloon dilation had a slightly longer symptom-free period than those treated with bougienage (Grundy and Belli, 1988). Stark et al (1984) reported a fourfold increase in the symptom-free interval following balloon dilation in a series of 10 patients who had undergone both conventional bougienage and balloon dilation. Lindor et al (1985) found no significant difference in their patients who had undergone previous conventional bougienage compared with the same patients who had undergone balloon dilation using a through-the-scope technique with balloons up to 20-mm fiiameter.

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Traditional weighted rubber dilators, such as the Hurst and Maloney bougies, are still used but are gradually being replaced by newer designs such as the Savary-Gilliard bougie (Wilson-Cook Medical Inc, Letchworth, England) which consists of a gently tapered, plastic-coated polyvinyl bougie that can be passed coaxially over a guide wire. The polyvinyl material is less apt to injure the patient’s teeth than the metal olive dilators (Tytgat, 1989). Patients may resent the repetitive passage of rigid bougies through the mouth and pharynx (Tytgat ,1989), and many patients who have undergone both bougienage and balloon dilation find the balloon method more acceptable. Bougienage has been shown to increase stricture diameter although the ultimate size is always less than the maximum bougie used. This rebound may vary from 1 mm to 11 mm. Rigid strictures generally show less rebound (Tytgat , 1989). Circumferential rather than eccentric lesions may be more amenable to balloon dilation. In eccentric non-circumferential narrowing, the pliable non-diseased segment may be displaced by the inflated balloon with little or no dilating force being applied to the diseased area (Tytgat, 1989). Balloon and bougie dilation differ in the forces generated during the procedure. The force that actually dilates the stricture is directed radially. Bougienage depends on advancing a tapered dilator to generate a radial force. As the bougie is passed through a stricture the longitudinal advancing force is converted into a shear force and a radially dilating force. The degree of each of these forces is related to the taper of the dilator and the frictional component of its surface. The major part of any force applied as a dilator is pushed through a stricture remains axially directed: this shear force stretches the oesophagus longitudinally, but does not contribute to the radial dilating effect (McLean and LeVeen, 1989). This longitudinal shear force is thought to predispose to rupture and it is suggested that the reduced longitudinal forces during balloon dilation reduce the risk of perforation. McLean and LeVeen (1989) conducted an experimental study employing the swine oesophagus to assess and measure longitudinal and radial forces during dilation with bougies and balloon catheters. They compared the Maloney bougie, the Savary-Gilliard dilator and an oesophageal balloon. The mean radial forces generated during dilation of artificially produced strictures did not differ significantly in the three dilating systems studied. The mean shear forces with the Maloney dilator were significantly higher than with the Savary-Gilliard dilator, and the shear force of the balloon was significantly lower than that with either bougie. The experiment was regarded as providing convincing evidence of the greater safety of balloon dilation of oesophageal strictures compared with conventional bougienage. COMPLICATIONS The normal oesophagus can be stretched to 1.6-2.0 times its resting diameter without perforation (Hoffer et al, 1987). In the literature on oesophageal dilation, use of balloon catheters is associated with a lower incidence of perforation than bougienage (Dawson

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et al, 1984; Stark et al, 1984; Lindor et al, 1985; Gotberg et al, 1982; McLean et al, 1987; Maynar et al, 1988). Oesophageal perforation in the course of balloon dilation is largely limited to patients with tumour invasion in the area being dilated (LaBerge et al, 1985; Gotberg et al, 1986; Maynar et al, 1988; Nobrega, 1989). In a series of 170 procedures (Maynar et al, 1988), three perforations occurred: two of these were during dilation of malignant strictures. The perforations were shown on contrast studies carried out immediately following dilation. Such studies are not used routinely but may be of value in preventing complete oesophageal rupture. The appearance of an outpouching or diverticulum-like structure at the site of the balloon dilation suggests a localized perforation and endoscopic evaluation should be carried out (Maynar et al, 1988). In the series of 257 dilations performed on 74 patients reported by Nobrega (1989), only one perforation occurred in a patient with a malignant stricture, even though 60 out of the 74 patients were being treated for malignant disease. De Lang and Shaffer (1988) reported two complications in 103 radiologically guided balloon dilations: a mucosal tear, and a perforation recognized immediately. Kozarek (1986) found a perforation rate of 0.4% in 486 patients undergoing balloon dilation for benign disease. Complications following balloon dilation may present quite some time after the procedure. La Berge et al (1985) described a patient who had been discharged following a procedure and who experienced chest pain 8 hours later; contrast studies showed extravasation along the medial wall of the oesophagus. The patient was treated conservatively with intravenous antibiotics and parenteral nutrition with resolution of the mediastinitis; subsequent open surgical biopsy 2 months later revealed a squamous cell carcinoma. Guide wire perforation of the oesophageal wall can be treated conservatively. An unusual reported complication was the development of generalized tonic-clonic seizures which were controlled by intravenous diazepam (Sawhney et al, 1990). The patient had been instructed to gargle with 10% lignocaine viscous fluid to anaesthetize the oropharynx and upper oesophagus rather than using a topical aerosol preparation, and it was presumed that the seizures were the result of lignocaine toxicity. ACHALASIA

Pneumatic dilation should be used as the initial treatment of achalasia; surgery is only indicated in cases of failure (Monges et al, 1985). Treatment of achalasia with forceful dilation purposely traumatizes the region of the lower oesophageal sphincter; the object is to cause sufficient tissue injury to eliminate the functional obstruction that exists in this disease (Ott et al, 1984). Variations in the methods of dilation of achalasia can range from undertreatment to overtreatment, resulting in ineffective dilation or an increased incidence of perforation (Sauer et al, 1989). Dilation in achalasia is a safe procedure, even in cachectic patients, with

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late results that compare favourably with those obtained by myotomy. Improvement is immediate, the risks are low, and the morbidity is considerably less than after thoracic or abdominal surgery. Surgery should be opted for after several unsuccessful attempts at dilation, when oesophageal carcinoma cannot be excluded, and in children and psychotic patients who are unable to cooperate. Diverticula of the lower segment of the oesophagus increase the risks of dilation and in these patients a myotomy may be safer (Vantrappen and Hellemans, 1980). High compliance balloons such as the Browne-McHardy, Negus and Mosher dilation catheters used for the management of achalasia, theoretically also subject the widened oesophageal wall proximal to the narrow zone to increased pressure, and subsequently to a higher risk of perforation. The new type of inelastic, cylindrical balloon, such as the Rigiflex achalasia dilator, seems to be safer, since it increases oesophageal wall tension in the stenotic zone only (Rabinovici et al, 1990). The low compliance of the balloon ensures that the

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Figure 3. (a) Barium swallow in a patient with achalasia. (b) The Rigiflex achalasia dilator being inflated up to 30 mm diameter at the lower oesophageal segment.

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shape of the balloon is maintained despite the inflation pressure produced (Griffin et al, 1989). The Rigiflex dilator for achalasia is a safe and effective instrument (Figure 3). Although it may be less effective than the Browne-McHardy dilator, the ability to position the balloon accurately, even in the patient with a markedly dilated and tortuous oesophagus, supports the suggestion that it is an attractive alternative to other dilating systems in the treatment of achalasia (Stark et al, 1990). Csendes et al (1989) have claimed that surgery is more effective than dilation in the management of achalasia, but their study has been criticized because they were not using the newer, more effective balloon dilation catheters (Dakkak and Bennett, 1989). Balloon dilation has been used successfully to manage two patients who had undergone inappropriate fundoplication for presumed reflux disease but were subsequently shown to have achalasia (Marshall, 1989). Stewart et al (1979) recommended contrast studies of the oesophagus immediately following every dilation of achalasia to detect oesophageal perforation, whereas Vreden and Yap (1990) recommended endoscopy following balloon dilation of achalasia to detect complications. Radiographic evaluation of the achalasic oesophagus immediately following pneumatic dilation showed one perforation in 16 patients studied by Ott et al (1984). In another recent series Barkin et al (1990) performed balloon dilation with the Rigiflex achalasia dilator as an outpatient procedure. Contrast studies performed within 4 hours of the procedure revealed two perforations, and no complications occurred in any patient who did not have chest pain within 4 hours of the procedure. Oesophageal tears have been described following pneumatic dilation using the Rider-Mueller balloon, and review of 58 contrast studies performed 1-15 days after dilation showed that 15% of contrast studies were abnormal. Incomplete tears were found in 7 patients, a linear mucosal tear in 1, and a localized outpouch or diverticulum in 6 (Adams et al, 1989). The main emphasis of radiographic examination after dilation therapy for achalasia has been to detect potential oesophageal perforation, but work by Agha and Lee (1986) showed that radiographic appearance correlated well with clinical response. Reduction of the diameter of the oesophagus and improvement in emptying were seen on contrast studies. Coordinated oesophageal peristalsis does not return after balloon dilation. On follow-up from 4 months to 24 months, 88% of patients had an overall satisfactory response. The incidence of reflux following balloon dilation of achalasia is up to 10% (Agha and Lee, 1986). In another study of 16 patients, it was found that the radiological appearances following dilation of achalasia poorly predicted patient response (Ott et al, 1984). Two out of three patients showing no increase in oesophagogastric calibre following dilation had symptomatic relief, while one of the clinically unimproved patients showed a substantial calibre increase. Symptomatic relief in achalasia has been reported for periods of up to 60 months following one or two dilations (Vreden and Yap, 1990). Patients with achalasia dilated to a lumen of 20mm in the region of the lower oesophageal sphincter usually require redilation every 3-4 months to remain

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symptom-free (McLean et al, 1987), but the use of the Rigiflex achalasia dilator now allows dilation up to 30mm diameter. BENIGN

OESOPHAGEAL

STRICTURES

The most common symptom of benign oesophageal stricture is dysphagia. Dilation rather than surgery is important, since many patients with benign oesophageal strictures are elderly and may have coexisting cardiac or pulmonary disease carrying a high surgical risk (Wesdorp et al, 1982). The most frequent causes of strictures are reflux oesophagitis and postsurgical narrowing. Stricture formation may also occur after radiation-induced oesophagitis and fibrosis (Taub et al, 1986). The stenosis must be corrected to improve quality of life, to improve nutritional status and to prevent aspiration into the lung and resultant infection (Luna, 1983). An oesophageal lumen less than 12mm in diameter virtually always results in dysphagia. The degree of functional disability with a lumen greater than 12mm appears to vary among patients. An oesophageal lumen diameter of 20mm allows the asymptomatic intake of a regular diet in the vast majority of patients (McLean et al, 1987). Reflux-induced strictures may be present at the gastro-oesophageal junction, or higher in the oesophagus in the case of Barrett’s syndrome (Tytgat, 1989). Upper oesophageal webs are usually thin mucosal diaphragms below the cricopharyngeal muscle and are easily ruptured by the passage of an endoscope or any type of dilator; a Shatzki’s ring can similarly be ruptured. Occasionally a Shatzki’s ring may be narrower and require balloon dilation or bougienage (Tytgat, 1989). Oesophageal stricture is also a common complication of endoscopic variceal sclerotherapy (Waring and Sanowski, 1988). Of 103 patients treated by sclerotherapy, 31 developed strictures; of these 5 presented with food impaction. The author’s experience of dilating radiation strictures has shown that these tend to be much more rigid than other strictures and have required a much greater dilating force (Grundy and Belli, 1988). Corrosive strictures are a relatively uncommon cause of oesophageal stenosis. Shemesh and Czerniak (1990) found that caustic strictures, even of long standing, were the easiest of strictures to dilate either with SavaryGilliard dilators or balloon catheters. Tytgat (1989), however, regards such strictures as the most difficult to dilate and the most likely to rupture. Caustic strictures seem to be relatively uncommon in British practice. At St George’s Hospital no caustic stricture has been encountered in the past 8 years of dilating oesophageal lesions. Sawhney et al (1990) have treated 4 patients with corrosive strictures successfully. The outcome following balloon dilation is difficult to assess. For benign stricturing, symptomatic success is often better than objective success as evaluated by either endoscopy or contrast studies (Tytgat, 1989). With the versatility of the existing equipment, it is virtually always possible to dilate a benign oesophageal stricture. Balloon catheter treatment of oesophageal strictures must be coupled with appropriate medical

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management to optimize the clinical response (Maynar et al, 1988). Rarely is resort to surgery needed, and even if surgery is considered for severe reflux disease, it may be valuable to dilate the stricture first rather than wait until after the antireflux surgery (Tytgat, 1989). Paediatric oesophageal strictures Balloon dilation can be used in the management of oesophageal strictures in children. Strictures are often seen following repair of oesophageal atresia, corrosive ingestion or foreign body impaction (Figure 4) (Ball et al, 1984; Goldthorn et al, 1984; Hoffer et al, 1987). Stricture at the site of oesophageal anastomosis following repair of oesophageal atresia may be presumed to be due to scar formation, although reflux oesophagitis may contribute to later formation of stenoses (Hoffer et al, 1987). More lasting results have been achieved using serial dilations at weekly or 2-weekly intervals, rather than attempting to manage a stricture at one dilation. Serial dilations may result in a more lasting effect due to progressive stretching of organizing scar tissue. Also graduated serial dilations prevent overstretching of an anastomotic stricture which may result in a intrathoracic tear (Goldthorn et al, 1984). The

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Figure 4. (a) A 3-year-old child with an upper oesophageal stricture (arrowed) following impaction of a foreign body. The foreign body was removed endoscopically and balloon dilation has been employed to dilate the stricture. Residual waisting is seen at the site of the stricture (b).

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successful management of an oesophageal stenosis following StevensJohnson syndrome by balloon dilation has been described (Rottermann et al, 1990). MALIGNANT

OESOPHAGEAL

STRICTURES

The role that balloon dilation should play in the dilation of malignant oesophageal strictures is difficult to define. These patients may already have undergone attempts at surgical resection or bypass radiation therapy, chemotherapy or a combination of these. Since cure of oesophageal carcinoma is rare, palliation of symptoms, especially dysphagia, is of paramount importance, Surgical resection is not possible in most patients and thus dysphagia becomes a significant and progressive problem early in the disease (Moses et al, 1985). During radiation therapy for oesophageal carcinoma, dysphagia may worsen (Moses et al, 1985)) and it may be feasible to dilate these patients to improve symptoms while undergoing radiotherapy. Special care should be taken if malignant strictures are to be dilated with balloons, since it is in this group that the majority of balloon-associated perforations have occurred (Gotberg et al, 1982; LaBerge et al, 1985; Maynar et al, 1988). Patients with malignant strictures managed by balloon dilation are more likely to have recurrent symptoms than those with benign lesions (McLean et al, 1987.). Nobrega (1989) has reported the use of balloon dilation in a series of 60 patients with malignant disease of the oesophagus. Balloon dilation allowed 82% of patients to swallow until near death. One rupture occurred and the patient died as a result of mediastinitis. Serial balloon catheter dilations under fluoroscopic guidance have allowed the eventual placement of an Atkinson tube to relieve a malignant oesophageal stricture in a patient with recurrent gastric carcinoma (Blundell and Burhenne, 1984). A similar technique performed as a one-stage dilation using a 15mm diameter balloon under fluoroscopic guidance, followed by insertion of a prosthetic device, was successful in 12 patients, with reduction in the operative time compared with conventional placement employing Eder-Puestow dilators (Chisholm et al, 1986). PYLORIC

DILATION

Gastric outlet obstruction secondary to peptic ulcer disease may be treated with balloon dilation with a success rate of up to 80%. Griffin et al (1989) have used an endoscopic method with a through-the-scope balloon catheter. A 15-mm diameter balloon was passed under direct vision and dilation performed under fluoroscopic vision. Watson and Katon (1988) described successful treatment of a postbulbar stricture secondary to peptic ulceration using an 18-mm diameter balloon passed through an endoscope. Caution should be exercised in the presence of active peptic disease, and peptic ulceration has been considered a contraindication to balloon dilation

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(Hogan et al, 1986). Temporary management of pyloric obstruction by balloon dilation using a 5mm balloon passed through an endoscope in a patient with gastric outlet obstruction and recent myocardial infarction has been used to allow a patient to tolerate oral feeding, and subsequent dilation was found to be unnecessary (Benjamin et al, 1982). Balloon dilation of pyloric obstruction following oesophagogastrectomy has also been used to improve gastric remnant emptying (Grundy and Belli, 1988). ANASTOMOTIC

STRICTURES

The formation of a stricture at an enteroenteric anastomosis in the upper gastrointestinal tract is a common complication that requires treatment if significant obstruction occurs (de Lange and Shaffer, 1988). Oesophagooesophageal, oesophagogastric, oesophagoileocolonic, gastrojejunal and gastroileal anastomoses have all been successfully dilated (Solt et al, 1984; de Lange and Shaffer, 1988; Grundy et al, 1990). It is logical to assume that a lesion resulting from a single discrete insult, of which the best example is surgery, should respond better to dilation than lesions resulting from a continuing disease process such as reflux oesophagitis. Long-term follow-up studies have tended to support this assumption (McLean and Meranze, 1989). There is a frequent association of anastomotic strictures with fistulae, and a narrowed anastomosis will contribute to the development and maintenance of a fistula. The leak usually reflects an inability of the distal bowel to conduct the normal enteric flow. The aetiology of anastomotic fistulae is not always clear: failure of the suture line due to dehiscence or trauma may be related to tumour in the suture line, ischaemia, stoma1 obstruction, pancreatitis or granulomatous disease of the bowel (Musher and Boyd, 1988). If distal obstruction is relieved, most surgical fistulae will close. Although it seems that dilating a stricture in the presence of an active leak might be dangerous since the integrity of the adjacent bowel wall is already compromised, it has been shown that fluoroscopically guided balloon dilation can be carried out safely and that healing of a fistula is greatly facilitated (de Lange et al, 1987; Grundy et al, 1990). The dilation can be safely carried out within the first 2 weeks following the initial surgical procedure (Figure 5). There are forms of anastomotic gastric outlet obstruction that are likely to be unresponsive to balloon dilation. A poorly positioned anastomosed loop of bowel may be kinked at or just distal to the anastomosis, or it may be brought through the transverse mesocolon at an unfavourable angle. In this situation the kink may resemble a true stricture on contrast studies. A balloon may be manipulated through such a lesion and show an encouraging appearance on inflation. However, with deflation the lesion promptly recurs as the bowel loop returns to its resting state. Attempts to identify such lesions on barium studies are important, since balloon dilation will be unsuccessful and operative repair will be needed (McLean and Meranze, 1989).

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(b)

Figure 5. (a) Following upper partial gastrectomy for gastric lymphoma, this patient developed a leak (arrow) from the anastomosis (arrowheads). Balloon dilation was performed, and a repeat contrast study 6 days later (b) showed the fistula to have healed and the anastomosis to be wider. From Grundy et al (1990) with permission.

Stenoses at gastroenterostomies should be dilated enough to prevent symptoms of obstruction, but not so much as to allow excessively rapid dumping of luminal contents into the anastomosed bowel. This is particularly important in patients who have had surgical procedures for morbid obesity, since maintenance of a restricted gastric emptying is a key factor in restricting their food intake and consequent weight loss. A luminal diameter of 12 mm for such patients is suggested, and a diameter of 15 mm for patients who have had gastroenterostomies for other reasons (McLean et al, 1987). Other authors have used H-mm diameter balloons to dilate gastrojejunostomy strictures following gastric bypass surgery for morbid obesity (Lineaweaver et al, 1985). The use of endoscopy to visualize the stoma, the orientation of which may have changed as a result of the invariable gastric distension in these patients, makes the procedure relatively easy to perform. This combined approach has electively been used in patients with strictures following gastroileal anastomoses for morbid obesity (Grundy et al, 1990). The target diameter for other enteric strictures should be determined from contrast studies of the adjacent, non-dilated normal bowel. There is little in the literature regarding the value of balloon dilation in strictures resulting from otolaryngeal surgery such as laryngectomy and pharyngectomy for carcinomas. Whitworth et al (1988) had two patients with jejunal interposition between the pharynx and oesophagus for the

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treatment of pharyngeal cancer. One patient had a stricture at the distal anastomosis which was dilated successfully, but the other patient had recurrent tumour and was a therapeutic failure. These authors also avoided dilation of anastomotic strictures elsewhere in the gastrointestinal tract for 6 weeks following surgery to prevent disruption of the anastomosis. In the author’s practice successful dilation was achieved in two patients with postlaryngectomy pharyngeal strictures and in two patients with pharyngeal strictures secondary to radiation for hypopharyngeal carcinoma (Figure 6).

Figure 6. A patient who had undergone total laryngectomy 10 years previously had been managing to dilate the anastomotic stricture himself with the use of gum-elastic bougies until he produced a perforation. The tortuous stricture was managed by regular balloon dilation. A steerable catheter facilitated negotiation of the stricture.

When dilating lesions in the upper oesophagus and hypopharynx, especially those occurring after laryngectomy, even in the presence of a permanent tracheostomy, the author has found that on inflation of the balloon catheter severe reflex coughing has been stimulated, presumably by a vagal reflex. In one patient this was so severe that the procedure had to be abandoned. Colonic anastomotic strictures are usually secondary to ischaemia or leakage. They are usually diagnosed at endoscopy or on contrast studies within the first 6 months after the original surgery (Pietropaolo et al, 1990). The now widespread use of the staple gun for enteric anastomoses may be

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responsible for an increased incidence of strictures. Contrast studies of defunctional bowel prior to closure of a defunctioning colostomy or ileostomy may identify an anastomotic stricture. Conservative management of colonic strictures based on the use of bulk-forming laxatives, stool softeners and enemas can be of some benefit, but the quality of life of these patients remains poor and surgical resection is a major procedure (Pietropaolo et al, 1990). Most rectal strictures respond to simple dilation but some will be relatively inaccessible. Balloon dilation of colonic strictures may be used to relieve obstructive symptoms and avoid the need for a defunctioning colostomy (Banerjee et al, 1991). Attempting to establish a near-normal enteric lumen poses some problems in the management of colonic and rectosigmoid lesions. Currently available balloons are up to 20mm in diameter. Although a lumen of 20mm will permit passage of small bowel contents and the watery faecal content of the right side of the colon, this is unlikely to be adequate for the distal large bowel. Two balloons can be used side by side to achieve an oval lumen of diameter up to 40mm, or three balloons together may produce an approximately circular lumen (McLean and Meranze, 1989). The Rigiflex achalasia balloon dilator has also been used for colonic stricture dilation (Pietropaolo et al, 1990). Nine patients with anastomotic strictures were treated successfully by means of endoscopically placed guide wire and a 20-mm Rigiflex catheter under fluoroscopic control (Aston et al, 1989). Six required a single dilation, but in two a second dilation was needed. One patient died after a third dilation produced a pneumoperitoneum which was presumed to be related to recurrent malignant disease at the anastomosis site. A mean follow-up period of 24 months without recurrence of symptoms was found in the other eight patients. Two benign sigmoid stricture dilations are described by Bellomi et al (1988). In one case four dilations were carried out in a period of 9 days before a satisfactory result was achieved. Solt and Papp (1988) have dilated six cases of postsurgical strictures of the rectosigmoid up to 20 mm in diameter using a combined colonoscopic and radiologic technique. Following the procedure, one of their patients developed a pyrexia which was managed conservatively. Dinneen and Motson (1991) have used throughthe-scope balloon dilation without radiological guidance in eight patients, with four patients requiring repeated dilation. In one patient with Crohn’s disease a colonic perforation occurred. Balloon dilation in cases of known tumour recurrence is not recommended since its effect can only be temporary, it involves greater risk of complication and may delay more adequate treatment (Solt and Papp, 1988). TJ Cleveland, AJ Shorthouse and MC Collins (personal communication) have carried out balloon dilations of strictured stapled anastomoses in 2 of their 25 patients who had ileal pouches and ileorectal anastomoses following total colectomy for ulcerative colitis. Strictures at the ileorectal staple line were dilated prior to closure of the defunctioning ileostomy. No large bowel preparation is needed prior to dilation of distal colonic strictures apart from a rectal washout on the morning of the procedure (Banerjee et al, 1991). For rectal and distal colonic strictures the patient should be positioned either in a left decubitus position (McLean et al, 1987),

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or the best position can be chosen from a water-soluble contrast study used to assess the lesion prior to dilation (Banerjee et al, 1991). Delayed colonic strictures in infants and children who have intestinal ischaemia of diverse aetiology including necrotizing enterocolitis have been treated by balloon dilation. Ball et al (1983) described three patients treated successfully with balloon dilation through the distal limb of a defunctioning colostomy in order to avoid manoeuvring through a tortuous sigmoid colon. The guide wire was positioned under fluoroscopy and the stricture dilated with angioplasty catheters ranging in size from 6 mm to 12 mm in diameter. Several balloon inflations were needed to achieve maximum dilation. No complications were encountered in the 10 dilations performed. An ischaemic stricture secondary to necrotizing enterocolitis was recently dilated using a rectal approach since a defunctioning colostomy had not been performed (Figure 7). Wilder and Melhem (1989) dilated a stricture occurring at a biopsy site for the diagnosis of Hirschsprung’s disease and another occurring following surgical repair of a rectodural fistula. The first case was approached via a colostomy, but the second was managed by rectal catheterization. Attention to technique and catheter placement as well as fluoroscopic time is essential when dealing with young children (Wilder and Melhem, 1989).

(4

(b)

7. A 2-month-old baby with a tight sigmoid stricture secondary to necrotizing enterocolitis. The stricture was negotiated using a soft feeding tube and J-shaped guide wire, followed by balloon dilation with a 12-mm angioplasty catheter (a). After dilation, a contrast study showed the stricture to have been dilated to a diameter of up to 8 mm (b).

Figure

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DISEASE

Balloon dilation of strictures due to Crohn’s disease may be carried out successfully. In a series of 12 patients with Crohn’s disease strictures at various sites in the gastrointestinal tract, encouraging results were obtained from balloon dilation carried out by endoscopic placement of a guide wire followed by fluoroscopically controlled balloon dilation or by balloon catheters inserted at laparotomy (Alexander-Williams et al, 1986). Williams and Palmer (1991) also recently reported their experience of effective dilation of short, fibrous strictures in 5 out of 7 patients treated by balloon dilation with Rigiflex catheters using an endoscopic approach. Dobson and Robertson (1988) dilated an ileocolic stricture by retrograde passage through a stoma of a guide wire under fluoroscopic control. Several balloon inflations were required, but the dilations produced temporary relief of the obstruction lasting only 3 months; the patient subsequently underwent surgical resection of the stricture. The ability to reach strictures in the jejunum and colon is mainly limited by the difficulties of access through the mouth, rectum or stomata, and by the length and flexibility of currently available balloon catheters, guide wires and endoscopes. Dilation of anorectal strictures in Crohn’s disease may be complicated by abscess formation or the relapse of an anorectal fistula (Linares et al, 1988). It is likely that dilation in these patients causes damage to the bowel wall resulting in faecal contamination of the pararectal tissues. The majority of anorectal strictures in Crohn’s disease can be managed by one or two dilations, but if repeated dilations are required most patients will require surgery to control symptoms (Linares et al, 1988). SUMMARY Balloon dilation of gastrointestinal strictures using a radiologic, endoscopic or combined approach is a safe, effective means of managing an everincreasing variety of stricturing processes. At present the ability to dilate strictures in the gastrointestinal tract is limited mainly by access. Balloon dilation is now well established in the management of oesophageal and anastomotic lesions. The place of balloon dilation in the management of Crohn’s disease and in the management of malignant disease requires further evaluation. REFERENCES Adams H, Roberts GM & Smith PM (1989) Oesophageal tears during pneumatic balloon dilatation for the treatment of achalasia. Clinical Radiology 40: 53-57. Agha FP & Lee HH (1986) The esophagus after endoscopic pneumatic balloon dilatation for achalasia. American Journal of Roentgenology 146: 25-29. Alexander-Williams J, Allan A, Morel P et al (1986) The therapeutic dilatation of enteric strictures due to Crohn’s disease. Annals of the Royal College of Surgeons of England 68: 95-97.

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