Effects of laparoscopic Roux-en-Y gastric bypass on bone mineral density and markers of bone turnover.

BACKGROUND: Despite multiple beneficial effects of weight loss after laparoscopic Roux-en-Y gastric bypass (LRYGB), the influence on bone mineral density (BMD) remains largely unknown. Our objective was to evaluate the changes in BMD and serum/urine bone markers after LRYGB. METHODS: Thirty-four women undergoing LRYGB were prospectively enrolled and underwent bone densitometry and serum/urine analysis preoperatively and 1 year postoperative. Changes≥.025 g/cm(2) in hip, femoral neck, and spine BMD and decreases>2% in total BMD were considered significant. Statistical analysis included paired t tests and McNemar's test. RESULTS: Mean age was 44.6 years. Body mass index at the preoperative and 1-year postoperative intervals were 46.7 and 29.6 kg/m(2), respectively. Mean hip, femoral neck, and spine (L1-L4) BMD was 1.191 versus 1.087 g/cm(2) (P< .001), 1.105 versus 1.032 g/cm(2) (P< .001), and 1.323 versus 1.277 g/cm(2) (P< .001) at the preoperative and 1 year postoperative intervals, respectively. Mean total BMD decreased from 1.328 preoperatively to 1.251 g/cm(2) at 1 year postoperative (P<.001). The decreases in BMD were 5.8%, 6.5%, 3.5%, and 8.8% for hip, femoral neck, spine (L1-L4) and total BMD from preoperative to 1 year postoperative. The proportion of patients with low vitamin D levels decreased from 55% preoperatively to 21% at 1 year postoperative (P = .004). Elevated osteocalcin and bone alkaline phosphatase was observed in 4% and 63% (P<.001), and 14% and 41% (P = .011) of patients preoperatively and at 1 year postoperative, respectively. CONCLUSION: BMD and bone markers changed significantly after LRYGB. Current recommendations for supplementation in post-LRYGB women may need to be reevaluated.

Incidence, treatment, and outcomes of iron deficiency after laparoscopic Roux-en-Y gastric bypass: a 10-year analysis.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (LRYGB) can lead to iron malabsorption through exclusion of the duodenum and proximal jejunum, decreased gastric acidity, and modified diet. Intravenous (IV) iron is a treatment for severe iron deficiency, but the incidence of iron deficiency and the frequency of treatment with IV iron after LRYGB are largely unknown. Our objective was to determine the incidence of iron deficiency and the frequency of IV iron administration after LRYGB. STUDY DESIGN: After obtaining IRB approval, the medical records of patients who underwent LRYGB from September 2001 to December 2011 were retrospectively reviewed. Inclusion criteria consisted of determination of at least 1 ferritin value after surgery. Patients were grouped by level of iron deficiency. Patients with at least 1 ferritin <50 ng/mL were considered iron deficient. Statistical analysis included ANOVA. RESULTS: There were 959 patients included; 84.9% were female. Mean age was 43.8 years, and preoperative body mass index was 47.4 kg/m(2). Four hundred ninety-two (51.3%) patients were iron deficient. Of these, 40.9% were severely iron deficient, with a ferritin <30 ng/mL. Intravenous iron was required by 6.7%. After IV iron therapy, 53% had improvement in hemoglobin and ferritin values, and 39% had improvement in ferritin values only. CONCLUSIONS: Given the incidence of iron deficiency after LRYGB observed in our series, patients should have iron status monitored carefully by all providers and be appropriately referred for treatment. Female patients should be counseled that there is a 50% chance they will become iron deficient after LRYGB.

A prospective, blinded comparison of laparoscopic ultrasound with transabdominal ultrasound for the detection of gallbladder pathology in morbidly obese patients.

BACKGROUND: Transabdominal ultrasound (TAU) is the gold standard for detecting cholelithiasis. Morbid obesity can inhibit detection of gallbladder pathology due to increased subcutaneous and visceral fat. Laparoscopic ultrasound (LUS) has the potential to overcome these technical challenges. We hypothesized that LUS would have a sensitivity and specificity similar to TAU for detecting cholelithiasis and polyps in morbidly obese patients presenting for laparoscopic Roux-en-Y gastric bypass. STUDY DESIGN: After Institutional Review Board approval, patients underwent preoperative TAU and intraoperative LUS during laparoscopic Roux-en-Y gastric bypass. Certified ultrasonographers performed all TAUs. Surgeons, blinded to TAU results, performed the LUS. Presence of cholelithiasis or polyps and common bile duct diameter was evaluated. Statistical analysis included chi-square and McNemar's test. RESULTS: Two hundred and fifty-three patients were prospectively enrolled during a 6-year period. Seventy-six percent were female, mean age and preoperative body mass index (calculated as kg/m(2)) were 43.5 years and 48, respectively. Mean time to complete the LUS was 4 minutes. Mean common bile duct diameter measured 3.7 mm via LUS and 4.0 mm via TAU. Transabdominal ultrasound and LUS identified 61 and 60 patients with cholelithiasis, respectively (p = 0.763). The sensitivity and specificity of LUS for cholelithiasis was 90.2% and 97.4%. Laparoscopic ultrasound identified polyps in 41 patients, and TAU identified polyps in 6 patients, 5 of which had polyps identified on LUS as well (p < 0.001). Sensitivity and specificity of LUS for polyps was 83.3% and 85.4%. CONCLUSIONS: Laparoscopic ultrasound is equivalent to TAU in detecting cholelithiasis, however, LUS detected significantly more polyps. Intraoperative LUS is an appropriate alternative to TAU in patients undergoing laparoscopic Roux-en-Y gastric bypass.