The LAP-BAND AP™ System: The Platform Advances

by Paul E. O’Brien, MD

Dr. O’Brien is from the Centre for Obesity Research and Education, Monash University, Melbourne, Victoria, Australia.

Background

Laparoscopic adjustable gastric banding (LAGB) has now been available through most of the world for more than 12 years with the introduction of the LAP-BAND® System in 1993.[1] By the mid-1990s, this approach had rapidly become the dominant bariatric surgical procedure in Europe, the Middle East, Mexico, much of South America, and Australia. The US became one of the last to gain access for clinical use in mid-2001. Regulatory requirements and unfavorable funding by insurers or health providers have been important factors in its slower introduction to Brazil and the US.

More than 1,200 papers or abstracts have been published on the LAGB, and it has now been accepted as a safe and efficacious approach to weight loss by the health services of all major governments.

It has not been a totally smooth transition from a new procedure without data on optimal technique or outcomes to the current level of acceptance. Optimal outcomes from the LAGB require good understanding of the correct positioning and stabilization of the band, good skills in perioperative bariatric patient care, and a high level of competence in laparoscopic surgery in the upper abdomen. Most importantly and often forgotten, the LAGB further requires both a commitment to the permanent aftercare of the patient in order to draw on the key LAGB advantage of adjustability, as well as ongoing dialogue between the surgeon and the patient on eating rules, exercise programs, and health management.

While the vast majority of reports have described very positive outcomes,[2-5] there have been some who were not able to achieve adequate effectiveness.[6,7] There has been a continuing need for improvements in training, better definition of optimal perioperative and aftercare techniques, and improvements in the device itself.
The LAP-BAND® System, the current market leader worldwide and the only LAGB currently available in the US, is almost identical to the band originally introduced in 1993. Two models have been available for several years now, based on band length—the 9.75cm and the 10cm bands. A newer model, the LAP-BAND® VG, with Omniform™ technology, was more recently introduced. Other manufacturers have entered the market and at least six different versions of LAGB are currently available in Europe. The best known of these, the Swedish Adjustable Gastric Band, or Obtech band, is in clinical trials in the US under an Investigational Device Exemption by the Food and Drug Administration.

The LAP-BAND® has been highly successful, with strong literature support showing good weight loss and an excellent safety profile. There has been extensive documentation of the health benefits derived from that weight loss.[8] Quality of life has been improved markedly and recently we have shown that there is a strong survival benefit for the band patient compared to obese community controls. However, all has not been perfect with the initial bands, and some of the unfavorable characteristics are listed in Table 1.

Table 1 and 2 Figure 1

The LAP-BAND AP™ (Advanced Performance)

The LAP-BAND AP™ System (Figure 1) is currently being introduced into clinical practice. It is designed to overcome any residual difficulties with the earlier bands. It is characterized by a smooth, circumferential balloon formed by a series of cushions, which provide gentle, even pressure to all areas of the underlying gastric wall. Even with complete filling, the creases remain quite shallow, reducing risk of erosion or balloon failure. It has two size options—the APS (small) and the APL (large).
The AP bands have a number of features that improve their ease of use or performance. These are listed in Table 2. These features the provide the following benefits:

Optimal gastric wall compression. It provides a smooth even compression of the gastric wall for the full 360º of the circumference. The primary mechanism of effect of the band is by induction of a feeling of satiety, a lack of hunger, and a reduced interest in food.[9] This effect is augmented by the 360º wrap and an increased width of the band.

Security against balloon failure. The balloon is molded to provide a series of cushions that evenly compress without deep creases forming in the balloon as the volume increases. This importantly reduces the risk of fracture of the balloon deep in the crease. Although this has not been an issue with earlier LAP-BAND®, it has been a negative feature of some of the alternative bands.

Avoidance of obstruction post-operatively. The inability to swallow fluids in the first few days immediately after LAP-BAND® placement was a frustrating problem that arose with the change from the perigastric to the pars flaccida path10 prior to the availability of the VG bands. Two features protect against this event. First, the AP band is easily opened at operation. If, at closure, the band appears too tight, it can be reopened, more perigastric fat be dissected, and the band be closed again. Secondly, the AP band has a basal volume of approximately 3mL. If there are symptoms or radiological features of delayed transit postoperatively, all or part of this 3mL of fluid can be removed.

Figure 3

Optimal range of area available to maximize control of satiety. Figure 3 shows the change in area with addition of saline to the APS and APL bands, the 9.75 cm, the 10cm band, and the VG. Note also that the APS closely follow the line of the 10cm band. However, at zero volume on the figure, the APS still has 3mL of extractable fluid. If it was too tight, removal of that fluid would increase the area to nearly 800mm2, making it similar to the VG. It therefore has the upper area range of a VG and the lower range of a 9.75cm band.

Reuse of the band with revision for prolapse. The ability to easily open the band permits its replacement along a new pathway as a part of revisional surgery, which can provide important cost saving for the patient or health provider.

Ease of surgical placement. The elimination of the “shoulders” compared to the earlier bands allows easy passage of the band around the pars flaccida pathway. The ability to reopen the band provides an important additional level of flexibility in dealing with excess perigastric fat.

Zero pressure system. Much has been made of the high intra balloon pressure of the 10cm band, even though that pressure has little impact on the interface pressure between the band and the gastric wall.[11] No such argument, no matter how spurious, could be made for the AP series.

Figure 4

Enhanced weight loss. Figure 4 shows the percent of excess weight loss (% EWL) achieved to date. At January 1, 2007, a total of 171 patients had a LAP-BAND AP™ System implanted. 114 have completed six months of follow-up and 25 have completed 12 months of follow-up. For comparison, the weight loss of those who have completed at least two years of follow-up after the 10cm bands (57% EWL; N=1521 patients) and the VG bands (48% EWL; N=155) are shown. The LAP-BAND® APS patients have lost 62 percent of their excess weight at 12 months, and the slope of the line is still steadily upward. The APL patients have 43 percent EWL. The 10cm band patients have 51 percent EWL and the VG band patients have 40 percent EWL at 12 months. If described in absolute terms, the APS patients have lost 27kg and 10.2 BMI units, bringing the mean BMI for the APS patients from 41.6 to 30.4 at 12 months and still progressing. There was an infection at the access port site in a 58-year-old male patient. The access port was removed. He presented at 11 months with erosion of the band into the stomach and had explantation laparoscopically. There have been no other adverse events.

Adjustment Sequence During Aftercare

Optimal adjustment of the LAGB is the key to achievement of best outcomes. The most common point of difference when a series with good outcome is compared to a series with unfavorable outcome is in the quantity and quality of the aftercare program. At follow-up visits, the adjustment of the band is just one part of a clinical consultation that includes clinical assessment and education. The concept of a “fill” as an isolated event without full clinical care is anathema to us. Importantly, we do not seek rapid weight loss, but steady progression of weight loss over 18 months to three years.
We are still refining the optimal sequence for adjusting specific to the LAP-BAND AP™ system. Our current protocol is as follows:

• There should be 3.0cc of “extractable” fluid at end of operation at zero intra-band pressure.
• All adjustments are performed as part of a clinical consultation in the office.
• Initial adjustment is performed at four weeks: Add 1.0 to 1.5cc to give a total of 4.0 to 4.5cc of extractable fluid. • Review every two weeks initially—Check weight loss, degree of satiety, symptoms, health. Advise patient regarding eating guidelines and exercise and activity programs.
* If losing less than 1.0lb/week—usually add fluid
* If losing more than 2.0lbs/week—usually no added fluid
* If between 0.5 and 1.0lbs/week—optional, based on satiety and symptoms.
• Usually add 0.5 to 1.0cc each time.
• When the “sweet spot” or “green zone” is achieved, review less often.
• Always review at least every six months permanently.

In the first year, the mean number of visits was 11.2 for the APS and 10.1 for the APL. At the end of the first year, the mean volume present was 5.9mL for the APS and 7.8mL for the APL. Thus far, no volume greater than 10mL has been placed, but the upper limit for these bands is not yet defined.

Discussion

The LAP-BAND® has been a major addition to our armamentarium in the treatment of obesity and its comorbidities. It has been extraordinarily safe; effective in achieving substantial and durable weight loss, improved health, and quality of life; and gentle in achieving these effects.[12] For a successful outcome, LAP-BAND® requires exact and stable positioning and an optimal aftercare program. The deficiencies in the structure of the original band were partly removed by the VG band after 2003 and now appear to be completely removed with the AP series. There should no longer be excess tightness in the early postoperative period. The induction of satiety is retained and possibly augmented by its larger footprint around the upper stomach. Ease of opening and a smooth shape allows for removal and replacement if repositioning is subsequently required.

Only very early data are yet available, but the weight loss for the APS is excellent, with results at 12 months being better than achieved with the earlier bands. There was a significant early period of uncertainty about the optimal adjustment schedule, and as we now have a much more secure schedule, it is likely that this favorable pattern of weight loss will be continued. For most patients, the maximum level of weight loss is expected to be achieved at 18 to 24 months after placement.

The APL band is not yet achieving as good weight loss when measured as %EWL. Partly, this is due to the larger patients being allocated to the APL group (mean BMI of 49.5 for APL; mean BMI of 41.6 for APS), and partly due to inadequate adjustments as we search for the optimal adjustment protocol. If weight change is expressed in absolute terms, there is an equivalence between the APS and APL in kg weight loss (APS=27kg; APL=31kg) and the change in BMI (APS=10.2; APL=11.6). If the area within each band is graphed against the added volume, two parallel slopes are derived, which are separate by a volume of approximately 3mL (Figure 3). Therefore, for the same patient to have an equivalent induction of satiety, 3mL more fluid would be needed for the APL compared to the APS. On the adjustments thus far, there is a mean difference of only 2mL, suggesting we may have been underfilling the APL patients. Optimal adjustment protocol will be developed with continuing experience.
As the evaluation of both bands has progressed, the ratio of use of the APS:APL has increased from an initial 2:1 to a current 10:1. Because the area profile of the APS can extend from the size of a VG band with no fluid added to an area less than the 9.75cm band, the APS could fill a position as the primary band, reserving the APL for use in only the extremely obese.

As the LAP-BAND® System now fills a mature and accepted role as an effective and safe weight loss surgical procedure, the advent of the AP series provides significant refinements that our early experience indicates will further improve its ability to achieve safe, substantial, and durable weight loss.

References
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