Dennis Blom

Medical College of Wisconsin, Milwaukee, WI, United States

Are you Dennis Blom?

Claim your profile

Publications (22)155.19 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Laparoscopic Nissen fundoplication (LNF) is the surgical treatment of choice for gastroesophageal reflux disease (GERD). Post-LNF complications, such as gas bloat syndrome, inability to belch and vomit, and dysphagia, remain too common and prevent LNF from being more highly recommended. It remains controversial as to whether preoperative assessment can predict the development of post-LNF complications. Some authors have shown a correlation between pre-LNF manometry characteristics and post-LNF dysphagia, and others have not. We hypothesize that many post-LNF complications are caused by a decrease in the distensibility of the GEJ and that standard manometry is at best an indirect measure of this. The aim of this study is to directly measure the effect of LNF on gastroesophageal junction (GEJ) distensibility (GEJD). The lower esophageal sphincter (LES) of 15 patients undergoing LNF was characterized using standard manometry. The GEJD before and after a standardized LNF was measured using a specialized catheter, containing an infinitely compliant bag, placed within the LES. GEJD was measured, as dV/dP over volumes 5 to 25 mL distended at a rate of 20 mL/min. Mean dP +/- standard error of the mean for each volume was calculated, and distensibility curves were generated and compared. Measurements were also taken after abolishing LES tone by mid-esophageal balloon distension. Patient symptoms were recorded before and after surgery. Statistical analysis was performed by two-way repeated-measures analysis of variance, paired t test, and the Tukey test. Laparoscopic Nissen fundoplication led to a statistically significant increase in Delta pressure over each volume tested and therefore a significant decrease in the distensibility of the GEJ. Abolition of LES tone had no statistical effect on GEJD after fundoplication. There were no complications, and none of the patients developed the symptom of dysphagia postoperatively. These are the first direct measurements to show that LNF significantly reduces the distensibility of the GEJ. We hypothesize that the magnitude of this reduction may be the vital variable in the development of post-LNF complications and specifically post-LNF dysphagia. The intraoperative measurement of LES distensibility may provide a means for avoiding this feared and other post-LNF complications in the future.
    Journal of Gastrointestinal Surgery 01/2006; 9(9):1318-25. · 2.36 Impact Factor
  • Source
    Digestive Diseases and Sciences 04/2005; 50(3):509-13. · 2.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ineffective esophageal motility disorder (IEM) is a new, manometrically defined, esophageal motility disorder, associated with severe gastroesophageal reflux disease (GERD), GERD-associated respiratory symptoms, delayed acid clearance, and mucosal injury. Videoesophagram is an important, inexpensive, and widely available tool in the diagnostic evaluation of patients with esophageal pathologies. The efficacy of videoesophagography has not been rigorously examined in patients with IEM. The aim of this study was to determine the diagnostic value of videoesophagography in patients with IEM. The radiographic and manometric findings of 202 consecutive patients presenting with foregut symptoms were evaluated. IEM was defined by strict manometric criteria. All other named motility disorders such as achalasia were excluded. Videoesophagography was performed according to a standard protocol. Of patients in this cohort, 16% (33/202) had IEM by manometric criteria. Of IEM patients, 55% (18/33) had an abnormal videoesophagram, while in 45% (15/33) this test was read as normal. Only 11% (15/137) of patients with a normal videoesophagram were found to have IEM. Sensitivity of videoesophagram was 54.6%, specificity 72.2%, positive predictive value only 27.7%, and negative predictive value 89.1% in the diagnosis of IEM. These data show that videoesophagram is relatively insensitive in detecting patients with IEM and should not be considered a valid diagnostic test for this disorder. We conclude that esophageal manometry is an indispensable diagnostic modality in the workup of a patient with suspected of IEM.
    Surgical Endoscopy 04/2004; 18(3):459-62. · 3.43 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The detection of gastroesophageal reflux (GER) has to date been limited to acid exposure observed on 24-h pH monitoring. It is clear, however that nonacid reflux can be a significant clinical problem. Recently, as impedance technology with the capacity to detect all types of reflux (acid, nonacid, liquid, mixed, and air) has been developed. Seventeen asymptomatic healthy volunteers underwent combined 24-h pH and impedance testing. In all patients, pH was measured at 5 cm above the lower esophageal sphincter (LES), and simultaneous impedance changes were recorded at 3, 5, 7, 9, 15, and 17 cm above the LES. Refluxes were classified as acid (drop in pH <4 for >5 sec), Nonacid, short acid, or nonacid delta based on chemical properties; they were further classified as liquid, mixed, or gas based on the physical refluxate detected by impedance changes. The height of the reflux entering the esophagus was classified as distal (<5 cm), intermediate (5-9 cm), or proximal (9-17 cm). A total of 868 reflux events were characterized. Fifty-nine percent of them were not conventional acid reflux and could only be detected by impedance changes. Less than 2% of the events that were detected by a fall in pH to <4 were not detected by impedance changes. Pure liquid reflux was seen in 35.4%, a mixed pattern in 36.3%, and a gas reflux in 26.7%. Liquid was confined to the distal esophagus in 30%; it reached the midesophagus in 58% and the proximal esophagus in 11%. Over half of GER events are not detected by pH studies. Liquid reflux reaches the mid and proximal esophagus 69% of the time and gas nearly always does (92%). The additional information provided by impedance technology is likely to have a major impact on the understanding and clinical management of patients with gastroesophageal reflux disease (GERD).
    Surgical Endoscopy 09/2003; 17(9):1380-5. · 3.43 Impact Factor
  • Dennis Blom
    [Show abstract] [Hide abstract]
    ABSTRACT: Esophageal carcinoma is a highly lethal disease with increasing prevalence and an equally dramatic epidemiologic shift. Its causal association with gastroesophageal reflux disease and adenocarcinoma of the esophagus is well established, and the molecular events underlying this progression from mucosal injury to metaplasia to dysplasia to carcinoma are now becoming clear. Current diagnostic modalities and preoperative staging systems have significant limitations. The extent of surgical resection for esophageal carcinoma remains controversial. Disease confined to the mucosa and submucosa is more common, and endoscopic ablative techniques have been proposed. However, preoperative evaluation of tumor depth and regional nodal metastases remains inadequate in these very early lesions and urges caution before adoption of therapies that may compromise cure. Patients with disease confined to the mucosa or submucosa should undergo resectional therapy aimed at removing the entire esophageal wall, including the periesophageal and perihiatal lymph nodes. For disease penetrating the submucosa, the extent of surgical therapy must be tailored to the objectives of treatment (cure vs palliation) and preoperative stage. Although data from seven prospective, randomized trials are encouraging, no clear survival benefit has been documented for neoadjuvant combined-modality therapy. Surgical resection remains the standard of care and best chance for cure in the treatment of esophageal malignancy, with combined-modality therapy reserved for prohibitive surgery candidates.
    Current Gastroenterology Reports 07/2003; 5(3):192-7.
  • Source
    Journal of the American College of Surgeons 09/2002; 195(2):241-50. · 4.50 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to determine whether preoperative physiologic factors can account for and be used to predict the development of postoperative dysphagia after laparoscopic Nissen fundoplication. One hundred sixty-three patients with gastroesophageal reflux disease underwent laparoscopic Nissen fundoplication with a median follow-up of 14 months (range 6 to 81 months). Preoperative dysphagia was present in 37% (60 of 163) and was relieved in all but five patients (92%). Female sex (P = 0.01) and the presence of a stricture (P = 0.02) were the only preoperative variables associated with the presence of preoperative dysphagia. Eight percent (8 of 103) of patients without preoperative dysphagia developed new-onset dysphagia, and of these 63% (5 of 8) had a normal lower esophageal sphincter (LES) (pressure >6 mm Hg; length >2 cm; abdominal length >1 cm). New-onset dysphagia was significantly more common in patients with a normal LES (22% [5 of 23] vs. 4% [3 of 80], P = 001). Patients with a normal LES had almost a sixfold increase in the risk of developing dysphagia as those with an abnormal LES (relative risk = 5.8). Only a preoperative normal LES (P = 0.02) or mean LES pressures (P = 0.04) were positively associated with the development of postoperative dysphagia. The severity of this dysphagia also showed a strong positive trend of increasing with mean preoperative LES pressures (P = 0.07). Finally, preoperative LES pressure significantly correlated with postoperative LES pressure (r = 0.48, P = 0.01) and with mean residual LES (nadir) pressure (r = 0.33, P = 0.05) offering insight into the mechanism of this dysphagia. In conclusion, preoperative LES parameters play a role in the development of dysphagia after laparoscopic Nissen fundoplication. Patients with a normal LES or high mean LES pressures are at increased risk for developing this complication and should be informed of this before laparoscopic Nissen fundoplication.
    Journal of Gastrointestinal Surgery 01/2002; 6(1):22-7; discussion 27-8. · 2.36 Impact Factor
  • Journal of The American College of Surgeons - J AMER COLL SURGEONS. 01/2002; 195(2):241-250.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Although there have been case reports describing trocar site herniation after laparoscopic fundoplication, its overall prevalence and the risk factors for its development are unclear. The records of 320 patients undergoing primary laparoscopic fundoplication as treatment for gastroesophageal reflex disease (GERD) or hiatal hernia between 1991 and 1999 were reviewed retrospectively. Placement of the initial supraumbilical trocar was by the open Hassan technique in all patients. Nine patients (five male) with a mean age 54 years (range, 37-75) developed trocar site herniation, for an overall prevalence of 3%. The mean interval between surgery and diagnosis was 12 months (range, 4-21). In all patients, the hernia occurred at the supraumbilical camera port site. Patients with trocar hernias tended to have a higher body mass index (BMI) than those without hernias (mean BMI, 29.4 kg/m2 vs 27.2 kg/m2, p = 0.13). None of the patients developed intestinal obstruction as a consequence of herniation. To date, all but one of the hernias have been repaired. Six of them required the insertion of a prosthetic mesh. The prevalence of trocar site herniation after laparoscopic fundoplication was minimal at 3%. All hernias occurred at the midline supraumbilical port, the only site where open trocar insertion was employed. As a consequence of these observations, we have developed a new method of open trocar placement. This method utilizes a paramedian skin incision and separate fascial incisions through anterior and posterior rectus sheathes, with retraction of the rectus abdominis muscle laterally.
    Surgical Endoscopy 08/2001; 15(7):663-6. · 3.43 Impact Factor
  • D Blom, S I Schwartz
    [Show abstract] [Hide abstract]
    ABSTRACT: To our knowledge, few individual surgeons and only a handful of institutions have gained a meaningful experience with the treatment of adenocarcinoma of the extrahepatic bile ducts or cholangiocarcinoma. The purpose of this study was to critically evaluate the experience of a single center in the treatment of these tumors. Retrospective cohort study with a median follow-up of 48 months. Department of surgery at a university referral center. Seventy-seven patients with biopsy-confirmed adenocarcinoma of the extrahepatic bile ducts evaluated and treated between January 1980 and February 1998. Prognostic variables, resectability rates, morbidity, and survival. Thirty-eight male and 39 female patients were studied (median age, 71 years). Twenty-three patients (30%) underwent curative resections, 32 patients (41%) underwent palliative surgery, and 22 patients (29%) received nonoperative therapies. The 30-day perioperative morbidity rate was 18%, and mortality was 6%. Overall median survival was 11 months; 4 months for patients receiving nonoperative therapy; 8 months for patients receiving palliative surgery; and 72 months for curative resection. Five-year survival rates were 23%, 0%, 10%, and 55%, respectively. Curative resection was the only prognostic variable to have a statistically significant effect on survival. Curative resection could be achieved in approximately one third of patients who had cholangiocarcinoma, and should be the goal of treatment. Survival is significantly improved in those patients who are considered to have resectable tumors and who undergo removal of all gross disease. Palliative surgical treatments also revealed a survival advantage over nonoperative therapies.
    Archives of Surgery 03/2001; 136(2):209-15. · 4.10 Impact Factor
  • Gastroenterology 01/2001; 120(5). · 12.82 Impact Factor
  • Gastroenterology 01/2001; 120(5). · 12.82 Impact Factor
  • R V Lord, D J Bowrey, D Blom
    The American Journal of Gastroenterology 12/2000; 95(11):3302-5. · 7.55 Impact Factor
  • D Blom, J H Peters
    [Show abstract] [Hide abstract]
    ABSTRACT: Esophageal carcinoma remains a highly lethal disease that has shown a recent profound increase in prevalence and an equally dramatic epidemiologic shift. There is a well recognized causal association between gastroesophageal reflux disease and adenocarcinoma of the esophagus, and the molecular events underlying this progression from mucosal injury, to metaplasia, to dysplasia, to carcinoma are now becoming clear. Current diagnostic modalities and preoperative staging systems all have significant limitations. Fortunately, chemoprevention strategies and the identification of clinically useful molecular biomarkers that may be used to stage disease and select appropriate therapy are on the horizon. The extent of surgical resection for esophageal carcinoma remains an area of great controversy. Disease that is confined to the mucosa is being diagnosed more commonly, and endoscopic ablative techniques have been proposed. To date, however, preoperative discrimination of tumor depth and presence of regional nodal metastases remains inadequate in these very early lesions, and caution is urged before adopting therapies that may compromise cure. For disease penetrating the mucosa, the extent of surgical therapy must be tailored by the objectives of treatment (cure vs palliation) and preoperative stage. Surgical resection is the current standard of care, with combined-modality therapy reserved for prohibitive surgical candidates. No clear survival benefit has been documented for neoadjuvant radiotherapy or chemotherapy alone. The results of preoperative combined-modality therapy, including three prospective, randomized trials, are encouraging but to date have not shown a definite benefit.
    Current Opinion in Gastroenterology 08/2000; 16(4):392-9. · 4.10 Impact Factor
  • D Blom, D J Bowrey, R V Lord
    The American Journal of Gastroenterology 05/2000; 95(4):1085-7. · 7.55 Impact Factor
  • D J Bowrey, D Blom, R V Lord
    The American Journal of Gastroenterology 05/2000; 95(4):1087-8. · 7.55 Impact Factor
  • Gastroenterology 01/2000; 118(4). · 12.82 Impact Factor
  • Gastroenterology 01/2000; 118(4). · 12.82 Impact Factor
  • Gastroenterology 01/2000; 118(4). · 12.82 Impact Factor
  • Gastroenterology 01/2000; 118(4). · 12.82 Impact Factor