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Gastrointestinal Imaging |
1 From the Departments of Medical Radiology, Institute of Diagnostic Radiology (W.W., M.H.), and Surgery, Division of Visceral Surgery (O.S., R.S.H.), Zurich University Hospital, Switzerland. From the 1998 RSNA scientific assembly. Received August 7, 1998; revision requested September 25; final revision received November 29, 1999; accepted December 7. Address correspondence to W.W., Institute of Diagnostic Radiology, Basel University Hospital, Petersgraben 4, CH-4031 Basel, Switzerland (e-mail: wwiesner@uhbs.ch).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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MATERIALS AND METHODS: From September 1995 to March 1998, 98 consecutive patients (18 men, 80 women; mean age, 39 years; age range, 22–62 years) with morbid obesity (mean body weight, 132 kg; mean body mass index, 47.1 kg/m2) underwent ALGB. In all patients, fluoroscopy was performed postoperatively to confirm band position and to exclude perforation and at 6–8 weeks later to measure and adjust the stoma between the pouch and stomach for optimal weight loss. All patients underwent another examination 12 months postoperatively, whereas patients with unsatisfactory weight loss or patients suspected of having complications were examined earlier and on several occasions.
RESULTS: Port puncture was feasible in all cases, and stomal adjustments could easily be repeated. Absolute (ie, total) weight loss after 1 year ranged from 8.8% to 39.2% (mean, 18.3%). Twenty patients showed unsatisfactory weight loss. No early complications occurred. Late complications occurred in 34 patients and included pouch dilatation (concentric or eccentric with posterior slippage), eccentric band herniation, band penetration, disconnection, axial pouch herniation, and port-site infection.
CONCLUSION: ALGB is an effective method in the treatment of morbid obesity. Radiographic assessments are crucial in the management of weight loss and detection of postoperative complications.
Index terms: Fluoroscopy • Laparoscopic surgery, 722.1269 • Obesity • Stomach, function, 722.91 • Stomach, surgery, 722.1269 • Surgery, complications, 72.458
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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The ALGB system (LAP-BAND; Bio-Enterics, Carpinteria, Calif) (Fig 1) consists of an implantable silicon band that is placed around the proximal stomach with the intention to form a small neostomach, which can also be termed a "pouch." The band is connected by means of a catheter to a subcutaneously implanted port accessible for percutaneous puncture and injection or aspiration of fluid, so that the ideal stomal width can easily be adjusted at any time.
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We assessed our experience with the first 98 patients undergoing ALGB at our institution, evaluated the role of radiographic assessment, and determined the range of possible postoperative complications.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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One day following ALGB, the first radiographic assessment was performed in all patients to establish the position of the band, check the different components of the system, and to exclude perforation. This single-contrast examination was performed by using a water-soluble contrast agent, meglumine and sodium diatrizoate (Gastrografin; Schering, Berlin, Germany), at a concentration of 340 mg/mL. The patient was requested to drink slowly in a supine position 100 mL of the contrast agent, while images (two to four per second) were obtained at the level of the carina and the ALGB site, in both AP and left anterior oblique projections. Follow-up images were obtained at the same levels.
Since at this first examination, the water-soluble contrast agent passes too quickly through the stoma and postoperative mucosal swelling may lead to additional narrowing of the stomach, the measurement of the stoma at this first assessment does not reflect the real (ie, functional) width of the passage through the stoma. To evaluate this width, a second radiographic assessment was undertaken 6–8 weeks following ALGB in all patients by using a thickened mixture of mashed potatoes and barium sulfate (Micropaque; Guerbet, Aulnay-sous-Bois, France) at a concentration of 100 mg/mL. In our experience, this thickened contrast medium leads to sufficient distention of the stoma, and because of the slower passage, the stomal width and the degree of obstruction at the position of the band are easier to evaluate. The patient was inclined at 45°, and special attention was given to imaging the ALGB site in a true lateral projection while imaging the passage of contrast material through the stoma at one to two images per second. In cases with suspected malpositioning of the band, additional lateral projections were obtained. Whenever band herniation was suspected, true en face projections were acquired. At the time of this second assessment, postoperative mucosal swelling has usually resolved and the thickened barium sulfate contrast material leads to a sufficient distention of the stoma. To obtain an optimal weight loss, the stoma was adjusted to 3–4 mm (7). After disinfection and surgical draping of the skin over the port implantation site, the center of the injection port was localized with fluoroscopy, and the port was punctured by using a specially designed 20-gauge, noncoring, deflected-tip needle (Access-Port Needle; Bio-Enterics). The use of local anesthesia was unnecessary in most cases. The needle was connected to a 5-mL Luer lock syringe over a saline-filled connecting tube so that the exact amount of saline to be injected into the port could be measured. After this procedure, another single-contrast barium study was performed in the manner described above in order to determine the caliber of the newly adjusted stoma (Fig 2).
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Patients disclosing sufficient weight loss were examined after 12 months to check the position of the band and to measure stomal width. Patients with insufficient weight loss were reexamined earlier in the follow-up to check that the stomal width had not changed. Patients with suspected complications were reexamined earlier and if necessary on several further occasions with or without additional stomal adjustments, but the high number of radiographic assessments in these patients represented only the difficulty in diagnosing certain complications (such as eccentric band herniation or intermittent eccentric pouch dilatation), which were unknown before March 1998.
The criteria for an additional follow-up examination were defined as (a) insufficient weight loss, (b) persistent regurgitation, (c) known eccentric band herniation, or (d) suspected intermittent posterior slippage. If insufficient weight loss was due to insufficient stomal adjustment, the stomal width was readjusted to 3–4 mm. If insufficient weight loss was secondary to noncompliance, the stomal width was not changed, but the patient was informed of his or her need to change nutritional habits in order to avoid chronic concentric pouch dilatation.
The fluoroscopic examinations were all performed by fellows supervised by dedicated staff radiologists and later on the images were reviewed by two (W.W., R.S.H.) or three (M.H.) authors in a consensus conference.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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The average amount of saline that had to be injected to adjust the stomal width to 3–4 mm ranged from 3.0 to 3.5 mL according to the position of the band and the thickness of the patient’s gastric wall. Weight loss and mobilization of body fat were monitored in each patient and corresponded well with the expected values. The average total weight loss was 9.3% at 3 months (range, 1.3%–19.2%), 13.9% at 6 months (range, 1.4%–28.8%), 18.3% at 12 months (range, 8.8%–39.2%), and 23.3% at 18 months (range, 11.6%–37.3%), respectively. In 78 patients, the observed weight loss was within the expected range and corresponded well with the results from prior studies (7–9). Unsatisfactory weight loss was found in 20 patients; in 19 patients this did not correlate with complications but was rather a result of poor patient compliance.
Complications
No early complications occurred. Late complications occurred in 34 patients and included concentric pouch dilatation (n = 7 [Fig 3]), eccentric pouch dilatation with posterior slippage of the band (n = 11, including two cases with partial stomach volvulus [Figs 4, 5]), eccentric herniation of the band (n = 6 [Fig 6]), disconnection of the system (n = 1 [Fig 7]), band penetration (n = 2 [Fig 8]), axial pouch herniation (n = 1), and soft-tissue infection around the port (n = 6, including one case with rotation of the port following local débridement) (Table). All cases of eccentric pouch dilatation disclosed a certain degree of posterior slippage of the band and were found only in patients with a transbursal ALGB procedure (ie, where the lesser sac was penetrated during retrogastric tunneling). After the surgical technique had been changed in early 1997 to suprabursal band positioning (ie, the band was placed around the stomach without opening the lesser sac during retrogastric tunneling), no further occurrences of eccentric pouch herniation were observed.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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Several complications can occur following ALGB (10–12). They can be divided into early and late postoperative complications. Malpositioning of the band and/or perforation are typical early complications, but were not seen in our patient group. However, various late complications were detected.
Regurgitation and pouch esophageal reflux are common postoperative complications, especially during the early postoperative weeks. In most cases, they are caused by unchanged nutritional habits, but they may persist in patients with insufficient antireflux mechanisms (13). The diagnostic approach is to exclude any obstruction at the site of the band such as an overnarrow stoma with concentric pouch dilatation, eccentric band herniation with concentric pouch dilatation, or posterior slippage with eccentric pouch dilatation. If none of these complications can be found, the patient should undergo nutritional counseling to change his or her nutritional habits to avoid chronic concentric pouch dilatation.
Pouch Dilatation
Pouch dilatation is known to be a possible complication following ALGB and may occur as an early or a late complication (14,15). Pouch dilatation can be divided into three types: acute concentric pouch dilatation, chronic concentric pouch dilatation, and eccentric pouch dilatation.
Acute concentric pouch dilatation.—This mostly occurs as a late complication and is mainly caused by a too narrow stoma and manifests as prestenotic dilatation of a part of the stomach fundus. The normal pouch, which should not be larger than 20 mL, can reach dimensions of up to 10 cm in diameter, and rarely axial herniation of the pouch may occur, as found in one patient in our series. There are several reasons for excessive stomal narrowing. It may be iatrogenic due to overfilling of the band by the radiologist (Fig 3). In such cases, simple puncture of the port and enlargement of the stoma to 3–4 mm by aspiration of 0.5–1.0 mL of saline is an appropriate treatment.
Eccentric band herniation is another rare cause for an acute concentric pouch dilatation and represents eccentric narrowing of the stoma due to a focal weakness of the band. If the eccentric band herniation occurs superiorly or inferiorly, then the width of the stoma will be underestimated radiographically. However, if eccentric band herniation occurs anteriorly or posteriorly, then the radiologist will overestimate the diameter of the stoma. An underestimated stoma will therefore probably lead to a better passage of food with subsequent insufficient weight loss, but an overestimated stoma may lead to a too narrow stoma with possible concentric pouch dilatation. Therefore, filling of the ALGB system with contrast agent and true en face projections are mandatory whenever eccentric band herniation is suspected. In one patient in our series, it was unclear why the patient developed pouch dilatation and showed pouch esophageal reflux—both signs of a narrow stoma—as the measured width of the stoma at radiographic follow-up was 4 mm. Later on, eccentric band herniation occurring posteriorly that lead to eccentric stomal narrowing was documented (Fig 6). The true stoma was only half (ie, 6 mm2) of the estimated stoma (
r2 = 4 = 12 mm2). After aspiration of some saline and adjustment of the measured stoma to 6 mm, the follow-up of this patient was normal.
Chronic concentric pouch dilatation.—Concentric pouch dilatation may also occur in the presence of a normal stoma of 3–4 mm if patients do not change their nutritional habits and chronically overfill their pouches, as was found in five patients. The reason for this special type of concentric pouch dilatation is a stoma that is only relatively too narrow. In contrast to an acute concentric pouch dilatation, such a "chronic" concentric pouch dilatation is not caused by an excessively narrow stoma but rather by a chronic volume overload of the pouch. The diagnosis of a chronic concentric pouch dilatation can be made on the basis of two findings: concentric pouch dilatation and normal stomal width. However, before this diagnosis can be made, eccentric band herniation with eccentric stomal narrowing from anterior or posterior must be excluded. These patients, too, have a certain degree of pouch esophageal reflux, mostly following a meal. Interestingly, some of these patients not only fill their pouch but also their distal esophagus during a meal. In these patients, therapy must consist of changing their nutritional habits and not of deflating the band, and whether or not the pouch reaches its normal size again depends on time and the degree of pouch dilatation.
Eccentric pouch dilatation.—This is the third type of pouch abnormality and mostly occurs as a late complication following posterior slippage of the band (Fig 4). Patients present with the same symptoms as with concentric pouch dilatation. This type of late complication was found in 11 patients in whom the band was placed by means of laparoscopic opening of the bursa omentalis (lesser sac) during retrogastric tunneling. After the surgical technique had been changed in early 1997 and the band was placed suprabursally (without penetrating the lesser sac), no further cases with posterior band slippage were observed. If posterior slippage is pronounced, the diagnosis is straightforward, because of the wrong position of the band and the appearance of the pouch itself and because the band remains at the wrong position even after emptying the system. Nevertheless, in such cases, the ideal procedure is complete system emptying to improve the passage through the stoma until the patient can undergo repeat surgery. A concentric dilated pouch secondary to narrowing of the stoma and with normal position of the band will shrink to a normal size within 1 or 2 days. Acute eccentric pouch dilatation due to dislocation (ie, posterior slippage) of the band with additional obstruction, however, will only partially decrease in size while the position of the band remains atypical and some degree of obstruction will persist (15).
Intermittent Posterior Slippage
Intermittent posterior slippage of the band with chronic eccentric pouch dilatation and without secondary obstruction is a rare complication and it can be very difficult to differentiate from chronic concentric pouch dilatation as the band can slip back to its normal position after the pouch has emptied or after deflating the system. In such cases, recurrent pouch dilatations after filling the system and precise knowledge of the surgical technique help to confirm the diagnosis. In chronic intermittent eccentric pouch dilatations, posterior slippage of the band is discrete and occurs only after filling the pouch. These patients have recurrent obstruction, and it is important to differentiate between chronic concentric pouch dilatation secondary to patient noncompliance (eg, chronic overfilling of the pouch in binge eaters) and chronic eccentric pouch dilatation due to an unstable band, as the latter requires surgical correction.
In cases with severe dislocation of the band (posterior slippage) and extreme eccentric pouch dilatation, additional complications, including gastric volvulus, infarction, and penetration, may occur as shown in two of our patients who had partial gastric volvulus after posterior band slippage and severe eccentric pouch dilatation, respectively. For this reason, any patient with documented posterior slippage must undergo repeat surgery.
System Disconnections
System disconnections are rare and can occur at three different locations: (a) at the connection between the port and the catheter, (b) at the connection between the proximal and distal parts of the catheter, and (c) at the connection between the catheter and the band. Disconnection can be caused by manipulation such as repositioning of the port due to patient discomfort or trauma. Clinically, these patients usually present with insufficient weight loss. Radiographically, this complication is easy to diagnose on a conventional abdominal radiograph and requires surgical correction.
Transmural Band Penetration
Seen in two patients in our series, transmural band penetration is a rare complication and is most probably caused by intraoperative damage of the serosa and outer muscular layers of the gastric wall and/or abuse of nonsteroidal antiinflammatory drugs (11,12). Transmural band penetration represents a typical late complication; it never occurs as an early complication because the band needs some time to penetrate the gastric wall. In one case from our series, the patient also had bulimia, and the initial tear may have occurred at one of the vomiting episodes. After the initial tear, the band will slowly grow through the gastric wall and may eventually penetrate into the lumen of the stomach. These patients may present with hematemesis and are often referred to exclude stomach perforation. This type of "chronic covered perforation" has a typical radiographic appearance, with contrast material around the part of the band that lies in the lumen of the stomach, and may lead to fatal bleeding. Knowledge about this complication is very important for the radiologist—first, because there are no other signs of open perforation or extravasation and second, because the patient requires urgent surgical treatment. Rebanding should only be done after reevaluation of the patient, since, as evidenced in our patient with bulimia, vomiting attacks and/or nonsteroidal antiinflammatory drug abuse may again cause the same complication later on in the course of the disease.
Infection around the Port
Soft-tissue infection around the port site is another possible complication in patients who have undergone ALGB, as is possible with virtually any implanted foreign body (8,11,12). Even if repeated punctures of the port are performed under sterile conditions, one may never be able to exclude possible low-grade infection at the time of radiographic follow-up. Close clinical examination is mandatory for early diagnosis of this complication, which can primarily be treated with oral antibiotics. Surgical therapy with local débridement and explantation of the port was however necessary in four of our patients.
Weight Loss
Unsatisfactory weight loss, as found in 20 patients, was not strongly correlated with the occurrence of other complications mentioned above. In most cases, patient noncompliance and change of nutritional habits, including ingestion of large quantities of high protein, fat, and carbohydrate liquids, were responsible for this. In these cases, radiographic assessments are often performed to exclude leakage of the system, but in most cases the pertinent medical history yields the correct diagnosis.
We conclude that ALGB is an efficient method in the therapy of morbid obesity, with the advantages of reversibility, adjustability, and low invasiveness, as opposed to alternative methods of bariatric surgery (16,17). Radiographic assessments are important both in the management of weight loss and the detection of the various postoperative complications that may occur.
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FOOTNOTES |
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Author contributions: Guarantor of integrity of entire study, M.H.; study concepts and design, W.W., M.H.; definition of intellectual content, W.W., M.H.; literature research, W.W.; clinical studies, all authors; data acquisition, W.W., O.S., R.S.H.; data analysis, W.W., R.S.H., M H.; manuscript preparation, W.W., M.H.; manuscript editing and review, M.H.
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REFERENCES |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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