Diabetic gastroparesis alters the biomagnetic signature of the gastric slow wave.

BACKGROUND: Gastroparesis is characterized by delayed gastric emptying without mechanical obstruction, but remains difficult to diagnose and distinguish from other gastrointestinal (GI) disorders. Gastroparesis affects the gastric slow wave, but non-invasive assessment has been limited to the electrogastrogram (EGG), which reliably characterizes temporal dynamics but does not provide spatial information. METHODS: We measured gastric slow wave parameters from the EGG and magnetogastrogram (MGG) in patients with gastroparesis and in healthy controls. In addition to dominant frequency (DF) and percentage power distribution (PPD), we measured the propagation velocity from MGG spatiotemporal patterns and the percentage of slow wave coupling (%SWC) from EGG. KEY RESULTS: No significant difference in DF was found between patients and controls. Gastroparesis patients had lower percentages of normogastric frequencies (60 ± 6% vs 78 ± 4%, p < 0.05), and higher brady (9 ± 2% vs 2 ± 1%, p < 0.05) and tachygastric (31 ± 2% vs 19 ± 1%, p < 0.05) frequency content postprandial, indicative of uncoupling. Propagation patterns were substantially different in patients and longitudinal propagation velocity was retrograde at 4.3 ± 2.9 mm/s vs anterograde at 7.4 ± 1.0 mm/s for controls (p < 0.01). No difference was found in %SWC from EGG. CONCLUSIONS & INFERENCES: Gastric slow wave parameters obtained from MGG recordings distinguish gastroparesis patients from controls. Assessment of slow wave propagation may prove critical to characterization of underlying disease processes. Future studies should determine pathologic indicators from MGG associated with other functional gastric disorders, and whether multichannel EGG with appropriate signal processing also reveals pathology.

Noninvasive biomagnetic detection of intestinal slow wave dysrhythmias in chronic mesenteric ischemia.

Chronic mesenteric ischemia (CMI) is a challenging clinical problem that is difficult to diagnose noninvasively. Diagnosis early in the disease process would enable life-saving early surgical intervention. Previous studies established that superconducting quantum interference device (SQUID) magnetometers detect the slow wave changes in the magnetoenterogram (MENG) noninvasively following induction of mesenteric ischemia in animal models. The purpose of this study was to assess functional physiological changes in the intestinal slow wave MENG of patients with chronic mesenteric ischemia. Pre- and postoperative studies were conducted on CMI patients using MENG and intraoperative recordings using invasive serosal electromyograms (EMG). Our preoperative MENG recordings showed that patients with CMI exhibited a significant decrease in intestinal slow wave frequency from 8.9 ± 0.3 cpm preprandial to 7.4 ± 0.1 cpm postprandial (P < 0.01) that was not observed in postoperative recordings (9.3 ± 0.2 cpm preprandial and 9.4 ± 0.4 cpm postprandial, P = 0.86). Intraoperative recording detected multiple frequencies from the ischemic portion of jejunum before revascularization, whereas normal serosal intestinal slow wave frequencies were observed after revascularization. The preoperative MENG data also showed signals with multiple frequencies suggestive of uncoupling and intestinal ischemia similar to intraoperative serosal EMG. Our results showed that multichannel MENG can identify intestinal slow wave dysrhythmias in CMI patients.

Effects of body mass index on gastric slow wave: a magnetogastrographic study.

We measured gastric slow wave activity simultaneously with magnetogastrogram (MGG), mucosal electromyogram (EMG) and electrogastrogram (EGG) in human subjects with varying body mass index (BMI) before and after a meal. In order to investigate the effect of BMI on gastric slow wave parameters, each subject's BMI was calculated and divided into two groups: subjects with BMI ≤ 27 and BMI > 27. Signals were processed with Fourier spectral analysis and second-order blind identification (SOBI) techniques. Our results showed that increased BMI does not affect signal characteristics such as frequency and amplitude of EMG and MGG. Comparison of the postprandial EGG power, on the other hand, showed a statistically significant reduction in subjects with BMI > 27 compared with BMI ≤ 27. In addition to the frequency and amplitude, the use of SOBI-computed propagation maps from MGG data allowed us to visualize the propagating slow wave and compute the propagation velocity in both BMI groups. No significant change in velocity with increasing BMI or meal was observed in our study. In conclusion, multichannel MGG provides an assessment of frequency, amplitude and propagation velocity of the slow wave in subjects with differing BMI categories and was observed to be independent of BMI.

Biomagnetic and bioelectric detection of gastric slow wave activity in normal human subjects--a correlation study.

We measured gastric slow wave activity simultaneously with a Superconducting Quantum Interference Device (SQUID) magnetometer, mucosal electrodes and cutaneous electrodes in 18 normal human subjects (11 women and 7 men). We processed signals with Fourier spectral analysis and SOBI blind-source separation techniques. We observed a high waveform correlation between the mucosal electromyogram (EMG) and multichannel SQUID magnetogastrogram (MGG). There was a lower waveform correlation between the mucosal EMG and cutaneous electrogastrogram (EGG), but the correlation improved with the application of SOBI. There was also a high correlation between the frequency of the electrical activity recorded in the MGG and in mucosal electrodes (r = 0.97). We concluded that SQUID magnetometers noninvasively record gastric slow wave activity that is highly correlated with the activity recorded by invasive mucosal electrodes.

Biomagnetic signatures of uncoupled gastric musculature.

Gastric slow waves propagate in the electrical syncytium of the healthy stomach, being generated at a rate of approximately three times per minute in a pacemaker region along the greater curvature of the antrum and propagating distally towards the pylorus. Disease states are known to alter the normal gastric slow wave. Recent studies have suggested the use of biomagnetic techniques for assessing parameters of the gastric slow wave that have potential diagnostic significance. We present a study in which the gastric syncytium was uncoupled by mechanical division as we recorded serosal electric potentials along with multichannel biomagnetic signals and cutaneous potentials. By computing the surface current density (SCD) from multichannel biomagnetic recordings, we were able to quantify gastric slow wave propagation as well as the frequency and amplitude of the slow wave and to show that these correlate well with similar parameters from serosal electrodes. We found the dominant slow wave frequency to be an unreliable indicator of gastric uncoupling as uncoupling results in the appearance of multiple slow wave sources at various frequencies in external recordings. The percentage of power distributed in specific frequency ranges exhibited significant postdivision changes. Propagation velocity determined from SCD maps was a weak indicator of uncoupling in this work; we believe that the relatively low spatial resolution of our 19-channel biomagnetometer confounds the characterization of spatial variations in slow wave propagation velocities. Nonetheless, the biomagnetic technique represents a non-invasive method for accurate determination of clinically significant parameters of the gastric slow wave.

Risk of secondary hyperparathyroidism after laparoscopic gastric bypass surgery in obese women.

BACKGROUND: Metabolic bone disease is a potential complication of bariatric surgery. The aims of our study were to evaluate the effects of laparoscopic gastric bypass on calcium and vitamin D metabolism, and to identify patients at high risk to develop secondary hyperparathyroidism (HPT). METHODS: Serum calcium, alkaline phosphatase, intact parathyroid hormone (PTH), and 25-hydroxy (OH) vitamin D were measured at 3, 6, 12, and 24 months after laparoscopic gastric bypass in a cohort of morbidly obese women. Logistic regression was used in both univariate and multivariate models to identify independent preoperative variables associated with secondary HPT. RESULTS: The study enrolled 193 morbidly obese women. During the 2-year follow-up period, the incidence of elevated PTH levels (>65 pg/ml) was 53.3%. The mean time elapsed between surgery and detection of secondary HPT was 9.1 months (range, 3-24 months). Vitamin D deficiency was observed in 39 patients (20.2%). On univariate analysis, the preoperative factors associated with secondary HPT were race (high PTH levels were detected in 70% of African Americans versus 50% of Caucasians; p < 0.05), preoperative body mass index (BMI; high PTH: 52.5 +/- 10.8 versus normal PTH: 48.9 +/- 7.5 kg/m2; p < 0.01), and age (high PTH: 44.9 +/- 9.2 versus normal PTH: 42.3 +/- 9 years, p < 0.05). Race and age remained independent risk factors for secondary HPT in the multivariate logistic regression model after adjusting for the covariate Roux-limb length. African Americans were at more than 2.5 times greater risk to develop secondary HPT as Caucasian (RR 2.5; 95% CI: 1.03-6.17, p < 0.05). Patients older than 45 years were at 1.8 times higher risk of developing secondary HPT as their younger counterparts (RR 1.8; 95% CI: 1.01-3.32, p < 0.05). CONCLUSIONS: Morbidly obese women have a high incidence of elevated PTH levels after gastric bypass surgery. Low vitamin D levels did not constitute the only reason behind this finding. African-American women and women older than 45 years of age were at significantly higher risk of developing secondary HPT. In these populations, aggressive supplementation with calcium citrate and vitamin D should be implemented.

A comparison of 399 open and 568 laparoscopic gastric bypasses performed during a 4-year period.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass surgery (RYGB) was introduced at the authors' institution 5 years ago. The authors analyzed the short- and long-term results of this procedure compared with those for the same procedure using the laparotomy approach over the same period. METHODS: Retrospective analysis of a prospectively collected bariatric database used the outcome end points used by the American Society of Bariatric Surgery (ASBS) and the American College of Surgeons (ACS) in their center of excellence programs. RESULTS: From January 2001 to July 2005, 568 laparoscopic and 399 open gastric bypasses were performed at Vanderbilt University. The patients were from the same bariatric surgery program and therefore received the same pre- and postoperative care. The hospital length of stay in the laparoscopic group was significantly shorter (2.5 +/- 2.4 days) than in the open group (3.7 +/- 3.7 days; p = 0.001). The procedure time was significantly shorter in the laparoscopic group (164 +/- 50 min) than in the open group (195 +/- 50 min; p = 0.0001). The follow-up assessment response at 2 years was 76.6%. At 2 years, the excess weight loss (EWL) was significantly greater in the laparoscopic group (71.3% +/- 18.4%) than in the open group (67.3% +/- 15.3%; p = 0.03). The wound infection rate was significantly higher in open group (9.2%) than in the laparoscopic group (1.7%; p = 0.001). There was no significant difference in 30-day mortality: open (0.50%) versus laparoscopic (0.17%; p = 0.371). There was no significant difference in the 30-day reoperation rate between the open (2.4%) and laparoscopic (2.6%; p = 0.705) groups. The 30-day readmission rate was similar in the open (5.0%) and laparoscopic (5.2%; p = 0.852) groups, as was the rate of leakage from the gastrojejunostomy in the open (0.50%) and laparoscopic (0.35%; p = 0.127) groups. The conversion rate from laparoscopic procedure to laparotomy was 1.7%. CONCLUSION: In the authors' institution, a laparoscopic bariatric surgery program with a very low rate of morbidity and mortality has been introduced. Operative time, hospital stay, and wound complications are reduced with the laparoscopic approach. The laparoscopic and open procedures are equally safe, with equivalent 30-day mortality, readmission, reoperation, and gastrojejunostomy leakage rates.

A biomagnetic assessment of colonic electrical activity in pigs.

The electrical control activity of the large intestine was recorded in six pigs using a SQUID magnetometer. The study was performed in pre- and post-colectomy/sham-colectomy conditions. The biomagnetic field associated with colonic ECA changed drastically in subjects that underwent the colectomy procedure, whereas the signal for the control animals was nearly unchanged. Power spectral analysis was used to determine the average changes of dominant frequency and amplitude between baseline versus colectomy and sham-colectomy conditions. The dominant frequency was increased by 68 +/- 24% (versus 2 +/- 3% in control). The amplitude was decreased by 69 +/- 24% (versus 13 +/- 17% in control). This is the first study of transabdominal magnetic fields associated with colonic ECA, suggests some of the side effects generated in colectomy surgery and shows the utility of the biomagnetic technique in studies of the large intestine.

The role of the surgeon in the evolution of flexible endoscopy.

Several cultures, including the Egyptians, Greeks, Romans, and Arabs, made attempts to view accessible human body cavities using a variety of instruments such as spatulas and specula. The first endoscope was created in 1806 when Phillip Bozzini, a German-born urologist, constructed the lichtleiter, which used concave mirrors to reflect candlelight through an open tube into the esophagus, bladder, or rectum. Maximilian Carl-Friedrich Nitze, another German urologist, produced the first usable cystoscope in 1877 by using series of lenses to increase magnification. He was also the first to place light inside the organ of interest to aid visualization. In 1880 Mikulicz made the first gastroscope using a system similar to Nitze's cystoscope. Modern endoscopy was born with the introduction of the fiberoptic endoscope in the late 1950s. Over the ensuing 50 years endoscopy revolutionized many aspects of the surgeon's practice. Endoscopy can now be used to diagnose and often treat gastrointestinal cancer, hemorrhage, obstruction, and inflammatory conditions. This review was initiated by the SAGES Flexible Endoscopy Committee to chronicle the role of the surgeon in the development and introduction of flexible endoscopy into clinical practice, historically and in contemporary surgery. Flexible endoscopy evolved out of surgeons' need to overcome diagnostic and therapeutic challenges. There have been many recent technological advances that facilitate endoluminal therapies, and flexible endoscopy is now traversing new ground. Surgeons have been major contributors in the development of all aspects of endoscopy. There is a continually expanding list of therapeutic options available to patients. The difficult questions of which procedure, on which patient, and when can be answered best by the surgeon versed in endoscopic, laparoscopic, and open surgical techniques.

Long-term evaluation of patient satisfaction and reflux symptoms after laparoscopic fundoplication with Collis gastroplasty.

BACKGROUND: Esophageal shortening is a complication of advanced gastroesophageal reflux disease (GERD). For patients with short esophagus, Collis gastroplasty combined with fundoplication provides excellent symptomatic relief from GERD disease. The literature lacks studies comparing satisfaction and reflux symptoms between patients who underwent Nissen fundoplication with Collis gastroplasty and those who had primary fundoplication alone. This study aimed to assess long-term satisfaction and GERD-related quality of life after laparoscopic Collis-Nissen fundoplication, and to compare them with those for Nissen fundoplication alone. METHODS: A nested case-control study was conducted. In this study, 14 cases of laparoscopic Collis-Nissen fundoplications were matched for age, gender, and length of the follow-up period to a cohort of 120 control subjects who underwent laparoscopic Nissen fundoplication. All the patients were mailed a follow-up survey which included a Short Form-12 (SF-12) health status (quality-of-life) questionnaire (a validated quality-of-life instrument), a Quality of Life in Reflux and Dyspepsia (QOLRAD) questionnaire (a GERD-specific quality-of-life instrument), and queries regarding long-term satisfaction and medication use. RESULTS: Both groups showed a significant postoperative increase in QOLRAD mean scores (p = 0.01). However, the difference in the delta (postoperative-preoperative) score between the two groups was not significant (Fig. 1). There were no differences in mental (MCS) or physical (PCS) SF-12 scores between the two groups. The rate of satisfaction with the surgery was similar in the Nissen-Collis fundoplication (87.5%) and Nissen fundoplication (87%) groups. CONCLUSIONS: Collis gastroplasty combined with Nissen fundoplication is an effective procedure for patients with a shortened esophagus diagnosed intraoperatively during antireflux surgery. Patient satisfaction, postoperative quality of life, and QOLRAD score improvement after this procedure are comparable with those observed in patients treated with Nissen fundoplication alone.

Biomagnetic characterization of spatiotemporal parameters of the gastric slow wave.

Certain gastric disorders affect spatiotemporal parameters of the gastric slow wave. Whereas the electrogastrogram (EGG) evaluates electric potentials to determine primarily temporal parameters, fundamental physical limitations imposed by the volume conduction properties of the abdomen suggest the evaluation of gastric magnetic fields. We used a multichannel superconducting quantum interference device magnetometer to study the magnetogastrogram (MGG) in 20 normal human subjects before and after a test meal. We computed the frequency and amplitude parameters of the gastric slow wave from MGG. We identified normal gastric slow wave activity with a frequency of 2.6 +/- 0.5 cycles per minute (cpm) preprandial and 2.8 +/- 0.3 cpm postprandial. In addition to frequency and amplitude, the use of surface current density mapping applied to the multichannel MGG allowed us to visualize the propagating slow wave and compute its propagation velocity (6.6 +/- 1.0 mm s(-1) preprandial and 7.4 +/- 0.4 mm s(-1) postprandial). Whereas MGG and EGG signals exhibited strong correlation, there was very little correlation between the MGG and manometry. The MGG not only records frequency dynamics of the gastric slow wave, but also characterizes gastric propagation. The MGG primarily reflects the underlying gastric electrical activity, but not its mechanical activity.

Predictors of success after laparoscopic gastric bypass: a multivariate analysis of socioeconomic factors.

BACKGROUND: Laparoscopic gastric bypass (LGB) has proven efficacy in causing significant and durable weight loss. However, the degree of postoperative weight loss and metabolic improvement varies greatly among individuals. Our study is aimed to identify independent predictors of successful weight loss after LGB. METHODS: Socioeconomic demographics were prospectively collected on patients undergoing LGB. Primary endpoint was percent of excess weight loss (EWL) at 1-year follow-up. Insufficient weight loss was defined as EWL or=52.8%. According to this definition, 147 patients (81.7%) achieved successful weight loss 1 year after LGB. On univariate analysis, preoperative BMI had a significant effect on EWL, with patients with BMI <50 achieving a higher percentage of EWL (91.7% vs 61.6%; p = 0.001). Marriage status was also a significant predictor of successful outcome, with single patients achieving a higher percentage of EWL than married patients (89.8% vs 77.7%; p = 0.04). Race had a noticeable but not statistically significant effect, with Caucasian patients achieving a higher percentage of EWL than African Americans (82.9% vs 60%; p = 0.06). Marital status remained an independent predictor of success in the multivariate logistic regression model after adjusting for covariates. Married patients were at more than two times the risk of failure compared to those who were unmarried (OR 2.6; 95% CI: 1.1-6.5, p = 0.04). CONCLUSIONS: Weight loss achieved at 1 year after LGB is suboptimal in superobese patients. Single patients with BMI < 50 had the best chance of achieving greater weight loss.

Heller myotomy vs Heller myotomy plus Dor fundoplication: cost-utility analysis of a randomized trial.

BACKGROUND: The addition of a Dor antireflux procedure reduces the risk of pathologic gastroesophageal reflux (GER) by ninefold following laparoscopic Heller myotomy for achalasia. It is not clear, however, how these benefits compare with the increased cost of the fundoplication. The objective of this study was to estimate the cost-effectiveness of Heller myotomy plus Dor fundoplication compared with Heller alone in patients with achalasia. METHODS: We conducted a cost-utility analysis using the Markov simulation model to examine the two treatment alternatives. The model estimated the total expected costs of each strategy over a 10-year time horizon. Data for the model were derived from our randomized clinical trial. The strategies were compared using the method of incremental cost-effectiveness analysis. RESULTS: The incidence of pathologic GER was 47.6% (10 of 21 patients) in the Heller group and 9.1% (2 of 22 patients) in the Heller plus Dor group using an intention-to-treat analysis (p = 0.005). Heller plus Dor was associated with a significant reduction in the risk of GERD (relative risk 0.11; 95% confidence interval 0.02-0.59; p = 0.01). The cost of surgery was significantly higher for Heller plus Dor than for Heller alone (mean difference $942; p = 0.04), secondary to a longer operating room time (mean difference 40 min; p = 0.01). At a time horizon of 10 years, when proton pump inhibitor (PPI) therapy costs are considered, the cost-utility analysis demonstrates that Heller plus Dor surgery is associated with a total cost of $6,861 per patient and a quality-adjusted life expectancy of 9.9 years, whereas Heller-alone surgery is associated with a cost of $9,541 per patient and a quality-adjusted life expectancy of 9.5 years. CONCLUSIONS: In achalasia patients, Heller myotomy plus Dor fundoplication is preferred to Heller alone because it is both more effective in preventing postoperative GERD and more cost-effective at a time horizon of 10 years.

Endoscopic evaluation of the gastrojejunostomy in laparoscopic gastric bypass. A series of 340 patients without postoperative leak.

BACKGROUND: A significant and potentially deadly complication of the Roux-en-Y gastric bypass is leakage from the gastrojejunostomy (GJ). The aim of our study was to evaluate the efficacy of intraoperative endoscopy in preventing postoperative anastomotic leakage. METHODS: The study enrolled 340 consecutive patients undergoing laparoscopic gastric bypass procedures performed from January 2001 to July 2004. In all cases, an endoscopist performed video gastroscopy to evaluate the integrity of the GJ using air insufflation of the pouch after distal clamping of the Roux limb. Intraoperative leaks were repaired and the anastomosis was retested. Demographic, operative, and endoscopic data were collected and analyzed. Logistic regression was used in both univariate and multivariate modeling to identify independent preoperative variables associated with the presence of intraoperative leak. Model parameters were estimated by the maximum likelihood method. From these estimates, odds ratios (ORs) with 95% confidence intervals (CIs) were computed. RESULTS: There were no postoperative anastomotic leaks or mortalities in our series. Overall, endoscopic evaluation of the GJ resulted in the detection of 56 intraoperative leaks (16.4%). There was a significant difference in the incidence of intraoperative leakage for patients older than 40 years (21%) vs those younger than 40 years (10.5%; p = 0.01). In the initial 91 cases, the GJ was performed by the end-to-end anastomosis (EEA) technique; the subsequent 249 were performed with a combination of linear stapling and handsewn technique. There was a trend toward more leakage in the GIA group (18%) versus EEA (12%); however, the difference was not significant (p = 0.188). Age remained an independent risk factor for leak detected intraoperatively in the multivariate logistic regression model after adjusting for covariates. Age >40 years increased the risk of intraoperative leakage by 2.3 times (OR, 2.3; 95% CI, 1.2-4.6; p = 0.01). The rate of postoperative anastomotic stricture was the same among patients detected with an intraoperative leak (5.4%) and those without (5.6%; p = 0.934). CONCLUSIONS: Endoscopic evaluation of the GJ is a sensitive and reliable technique for demonstrating anastomotic integrity and preventing postoperative morbidity after gastric bypass. Age >40 years was identified as an independent risk factor for intraoperative leak in this series.

Vector projection of biomagnetic fields.

Biomagnetic measurements are increasingly popular as functional imaging techniques for the non-invasive assessment of electrically active tissue. Although most currently available magnetometers utilise only one component of the vector magnetic field, some studies have suggested the possibility of obtaining additional information from recordings of the full magnetic field vector. Three projection techniques were applied to different biomagnetic signals for analysis of the three orthogonal components of the vector magnetic field. Vector magnetic fields obtained from fetal cardiac activity were projected into evenly spaced directions around a unit sphere. The vector magnetic field recorded from multiple intestinal current sources with independent temporal frequencies was then projected. Finally, an external reference signal from an invasive electrode was used to project the recorded vector magnetic fields due to gastric electrical activity. In each case, it was found that the information obtained by examination of the projected magnetic field vectors gave superior clinical insight to that obtained by analysis of any single magnetic field component.

The impact of a laparoscopic colorectal surgeon on the laparoscopic colectomy experience of a single academic center.

BACKGROUND: The objective of this study was to evaluate the impact of a laparoscopic colorectal surgeon (LCRS) on the laparoscopic colectomy experience of a single academic center. METHODS: We performed a retrospective review of case complexity, patient characteristics, operative and preparation time, and trends over time for the LCRS compared to two veteran laparoscopic surgeons (VLS). RESULTS: The LCRS performed 48 of the procedures (83%) and the VLS 10 (17%) for a total of 58 laparoscopic colon cases. The LCRS handled a greater number of complex cases (p = 0.07). For less complex cases, overall operative time differed for the two groups (LCRS = 220 +/- 11 vs VLS = 152 +/- 15 min, p = 0.004). Overall hospital stay was 4.8 +/- 0.6 days (range, 2-33). Minor complications occurred in 12 cases (21%); major complications in occurred in seven cases (12%). Among procedures performed by the LCRS, comparison of the first 24 cases to the second 24 demonstrated that operative and preparation time decreased in the second cohort (all p < 0.05). CONCLUSION: The addition of an LCRS had a significant impact on this center's experience with laparoscopic colectomies in terms of both volume and case complexity.

Three year's experience with the Stretta procedure: did it really make a difference?

BACKGROUND: Endoscopic treatment is merging as a new option for GERD treatment. Many modalities have been used with modest short-term success, but no long-term follow-ups have been published. We present our 3-yr experience at Vanderbilt University using endoscopic radiofrequency energy (Stretta procedure) for GERD treatment. METHODS: Patients with follow-up >6 months were prospectively studied under IRB protocol. All were mailed SF-12 health status questionnaire and GERD specific quality-of-life (QOLRAD) questionnaires, queries about satisfaction with Stretta, and medication use. All were invited for 24-hour pH study. RESULTS: Eighty-six Stretta procedures were performed between 8/2000 and 7/2003 on 85 patients; all were outpatients, 89% under conscious sedation. Seventy-seven patients qualified for the study; 61 completed the survey, 24 returned for pH study. Follow-up was 26.2 +/- 7.5 months (6-36). All were on daily PPIs, with proven GERD by pH study or endoscopy. Mean preoperative acid exposure time was 7.8+/-2.6%, mean DeMeester score was 40.2+/-17.6. Postoperative mean acid exposure time was 5.1+/-3.3 (p=0.001), DeMeester score was 29.5+/-20.5 (p=0.041). Normal postoperative acid exposure time (pH<4 in <4.2%) was achieved in 42% of patients tested. Patients were then divided according to medication use at the end of f/u in 2 groups: Responders (off or >50% decrease in PPI dose), and nonresponders (on >50% of original PPI dose, or had fundoplication). Response rate was 60% (39 patients), 8 nonresponders underwent fundoplication (12%). Satisfaction rate was 73%. Statistically significant difference was found between the 2 groups in all measurements; SF-12 physical and mental score for responders were 45.5+/-10.2, and 52.6+/-7.8; and for nonresponders were 37.8+/-11.2 and 40.9+/-11.3 (p=0.012, p=0.0001), respectively. Statistically significant difference was also found between responders and nonresponders in postoperative acid exposure (4.5+/-3.34 vs 7.2+/-2.3, p=0.034), and DeMeester score (26.3+/-20.4 vs 39.7+/-20.2, p=0.05). Paired T test was used to compare pre- and postoperative acid exposure in each group; statistically significant difference was found only among responders: total reflux time was 7.50+/-2.3 preop and 4.5+/-3.34 postop (p=0.0001), whereas for nonresponders it was 8.6+/-3.7 and 7.2+/-2.3 (p=0.8), DeMeester scores pre- and postop among responders were 40.0+/-19.7 and 26.3+/-20.4, respectively (p=0.016), whereas for nonresponders it was 40.5+/-14.3 and 39.7+/-20.2 (p=0.79). CONCLUSIONS: Stretta is a safe modestly effective, totally endoscopic treatment for GERD. Symptomatic improvement when achieved is often associated with correlating improvement in distal acid exposure. This exposure normalizes in nearly half the treated patients.

An anatomical model of the gastric system for producing bioelectric and biomagnetic fields.

Between 60 and 70 million people in the United States are affected by gastrointestinal disorders. Many of these conditions are difficult to assess without surgical intervention and accurate noninvasive techniques to aid in clinical assessment are needed. Through the use of a superconducting quantum interference device (SQUID) gradiometer, the weak magnetic field generated as a result of muscular activity in the digestive system can be measured. However, the interpretation of these magnetic recordings remains a significant challenge. We have created an anatomically realistic biophysically based mathematical model of the human digestive system and using this model normal gastric electrical control activity (ECA) has been simulated. The external magnetic fields associated with this gastric ECA have also been computed and are shown to be in qualitative agreement with recordings taken from normal individuals. The model framework thus provides a rational basis from which to begin interpreting magnetic recordings from normal and diseased individuals.

Laparoscopic fundoplication: 5-year follow-up.

There are few published reports on outcomes of 5 or more years following laparoscopic fundoplication. Gastroesophageal reflux disease (GERD) specific quality of life questionnaires (QOLRAD), short form health surveys (SF12), and queries regarding current medication use and long-term satisfaction were mailed to all patients who underwent laparoscopic fundoplication at our institution. Results are reported as mean +/- SEM. Seventy-six patients underwent laparoscopic fundoplication (63 Nissen, 13 Toupet) between November 1992 and December 1997. Fifty-two patients completed questionnaires (68%). Mean follow-up was 5.1 +/- 0.2 years (range, 4-9 years). Mean QOLRAD scores were 5.8 +/- 0.2, (scale 0-7, a higher score reflecting improved QOL), which is comparable to the general population (6.0 mean). SF-12 mental and physical scores were 46.6 +/- 1.7 and 34.2 +/- 1.6, respectively, versus 50.7 and 51.2 for the general population. Forty-seven patients (92%) would have the procedure again. Eleven (21%) remained on antisecretory medications (15% proton pump inhibitor and 6% H2 receptor antagonists). None of the 11 patients underwent 24-hour pH testing to document persistent acid exposure. Furthermore, postoperative symptoms of heartburn, dysphagia, and abdominal bloating were rated as none to mild in the majority of patients. Laparoscopic fundoplication is an effective long-term treatment for GERD, resulting in high patient satisfaction, improved quality of life, and elimination of antisecretory medicines in the majority of patients.