Weight loss associated with almost complete resolution of sleep apnea was observed by Schwartz et al. [454] in those patients with ob- structive sleep apnea (OSA) in whom the up- per airway critical pressure fell below minus 4 cm H
2O. They concluded that weight loss was associated with a reduction in upper air- way collapsibility and that resolution of sleep apnea depends on the absolute value to which the upper airway critical pressure falls. Un- fortunately, only a few patients with sleep-re- lated breathing disorders succeed in main- taining their weight reduction. Guilleminault [183] reports that only 3 % of patients with OSA who experienced a significant improve- ment in their sleep apnea symptoms as a re- sult of weight loss maintained their weight af- ter 5 years; many patients, in fact, regained their weight and even exceeded their baseline weight.
In a series of 216 overweight patients with OSA, resolution of OSA by means of weight loss alone was successful in 11.1 % of patients (n=24) [441]. Patients were re-examined after an average of 94.3±27.4 months. While 13 pa- tients had maintained their weight, 11 had regained lost weight. Furthermore, six of the 13 patients (46 %) who had maintained their weight had redeveloped clinically manifest OSA (apnea hypopnea index 40.5±24.1). On the other hand, nine of 11 patients (82 %) who had regained lost weight exhibited manifest OSA. Thus, after 3 years, only 3 % of patients showed relief of OSA. The authors point out a significant intraindividual variability and recommend periodic follow-up of these pa- tients as a reinforcement for weight mainte- nance and for early detection of the reappear- ance of OSA.
On the other hand, Guilleminault [183] also reports promising 5-year results in morbidly obese females who had undergone gastric surgery.
Prior to 1999, bariatric surgery was largely performed using an open technique. The number of procedures done in the USA was relatively stable: between 10,000 and 15,000 per year. The numbers increased to 75,000 in 2002. Much of the increase in the number of procedures performed reflects the sudden ex- plosion during this time of the use of a la- paroscopic approach for the performance of bariatric surgery [450]. Two operative ap- proaches are commonly performed – the ver- tical banded gastroplasty and Roux-en-Y gas- tric bypass [24, 88]. By limiting the storage capacity of the stomach to 30–50 cm
3and re- ducing the pouch-emptying rate by creating a 10 mm diameter anastomotic gastrointestinal stoma, these two gastric restrictive surgeries significantly reduce the total volume and rate at which food can be consumed. The gastric bypass further limits caloric intake by induc- ing a dumping syndrome whenever sugar is consumed [51]. In general, mean weight loss is greater after gastric bypass than after verti- cal banded gastroplasty.
12.1 Effectiveness for OSA
In general, reliable and substantial weight loss can be accomplished by gastric bypass surgery with accompanying major reduc- tions in associated co-morbidities [105]. The currently still limited polysomnographic data on the effect of gastric surgery for OSA are listed in Table 12.1.
Bariatric Surgery 12
In addition to the data presented in Table 12.1, we found a case report of successful normalization of severe OSA and morbid obesity after vertical silastic ring gastroplasty [501]. Three months after surgery the patient stopped nasal continuous positive airway pressure (CPAP) ventilation during his 2- week holiday without reoccurrence of day- time fatigue.
On the other hand, it has to be mentioned that in the long run there are cases of recur- rence of sleep apnea without concomitant weight increase, as described in 14 cases 7.5 years after successful weight reduction sur- gery [387]. Comparable results have been seen after dietary weight loss as well [441].
Nevertheless, these patients might gain access to upper airway surgery, as being severely overweight is one of the negative predictors for successful sleep apnea surgery in general.
12.2 Postoperative Care and Complications
The incidence of obstructive sleep-disor- dered breathing has been shown to be almost 90 % in severely obese patients [151]. There- fore we strongly recommend putting these patients onto CPAP ventilation before sur- gery. Empiric CPAP at 10 cm H
2O can be con- sidered for those patients who cannot com- plete a polysomnography. The patient should continue to use the CPAP device until broad weight reduction has been achieved. Espe- cially during the immediate postoperative pe- riod, the CPAP device may be needed to pro- tect the upper airway until sedative and muscle-relaxing drugs have been metabo- lized [222].
Many surgeons now perform these proce- dures using a laparoscopic approach, thus minimizing hospital stay and time of recov- ery. Complications after bariatric surgery can be divided into intraoperative, perioperative, and late complications. Iatrogenic splenec- tomies have been reported as an intraopera- tive complication after open gastric bypass operations. Podnos and colleagues [394] re-
128 Chapter 12 Bariatric Surgery
Table 12.1 Effect of gastric surgery on the severity of obstructive sleep apnea.
Author n Surgery Follow-up BMI BMI AHI AHI p value EBM (months) pre post pre post grade
Charuzi et al. 13 Gastric 6 222.5% 150% 88.8 8.0 <0.0005 II-3
1985 [75] bypass
Sugerman et al. 40 Gastric 69.6 56 40 64 26 0.0001 Retro
1992 [499] bypass ±28.8
or VBG or HG
Scheuller and 15 Gastric 12–144 160 kg 105 kg 96.9 11.3 <0.0001 II-3 Wieder 2001 [448] bypass
or VBG
Guardiano et al. 8 Gastric 28±20 49 34 55 14 =0.01 II-3
2003 [175] bypass
Rasheid et al. 11 Gastric 3–21 62 40 56 23 <0.05 II-3
2003 [408] bypass
All 87 3–144 56.2
a39.2
a71.5 19.3 IV
a
