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Biomedical subjects

M A Carlson

Publications and source records attributed to M A Carlson.

At least 19 recordsLinked to original sources
PubMed2006

Prosthetic closure of the esophageal hiatus in large hiatal hernia repair and laparoscopic antireflux surgery.

BACKGROUND: Laparoscopy has become the standard surgical approach to both surgery for gastroesophageal reflux disease and large/paraesophageal hiatal hernia repair with excellent long-term results and high patient satisfaction. However, several studies have shown that laparoscopic hiatal hernia repair is associated with high recurrence rates. Therefore, some authors recommend the use of prosthetic meshes for either laparoscopic large hiatal hernia repair or laparoscopic antireflux surgery. The aim of this article was to review available studies regarding the evolution, different techniques, results, and future perspectives concerning the use of prosthetic materials for closure of the esophageal hiatus. METHODS: A search of electronic databases, including Medline and Embase, was performed to identify available articles regarding prosthetic hiatal closure for large hiatal or paraesophageal hernia repair and/or laparoscopic antireflux surgery. Techniques and results as well as recurrence rates and complications related to the use of prosthetics for hiatal closure were reviewed and compared. Additionally, recent experiences and recommendations of experienced experts in this field were collected. RESULTS: The results of 42 studies were analyzed in this review. Some techniques of mesh hiatal closure were evaluated; however, most authors prefer posterior mesh cruroplasty. The type and shape of hiatal meshes vary from small angular meshes to A-shaped, V-shaped, or complete circular meshes. The most frequently utilized materials are polypropylene, polytetrafluoroethylene, or dual meshes. All studies show a low rate of postoperative hernia recurrence, with no mortality and low morbidity. In particular, comparative studies including two prospective randomized trials comparing simple sutured hiatal closure to prosthetic hiatal closure show a significantly lower rate of postoperative hiatal hernia recurrence and/or intrathoracic wrap migration in patients who underwent prosthetic hiatal closure. CONCLUSIONS: Laparoscopic large hiatal/paraesophageal hernia repair with prosthetic meshes as well as laparoscopic antireflux surgery with prosthetic hiatal closure are safe and effective procedures to prevent hiatal hernia recurrence and/or postoperative intrathoracic wrap migration, with low complication rates. The type of mesh, particularly the size and shape, is still controversial and is a matter for future research in this field.

Esophagus↗
PubMed2004

Minimally invasive incisional herniorrhaphy: a review of 208 cases.

BACKGROUND: Minimally invasive incisional herniorrhaphy has become an accepted approach for incisional hernia. However, the ideal technique for this procedure is not known. The authors present their technique and personal experience with minimally invasive incisional herniorrhaphy. METHODS: A retrospective review investigated 208 consecutive patients who underwent minimally invasive incisional hernia repair under the supervision of a single surgeon between 1995 and 2002. RESULTS: An intraperitoneal mesh repair was performed in all cases. There were no conversions. The mean operative time was 2.1 h (range, 0.8-4.5 h). The mean length of hospital stay was 2.5 days (range, 0-13 days). There were six complications, including two bowel perforations, and zero mortality. There were three recurrences during the follow-up period, which ranged from 6 to 72 months (median, 24 months). CONCLUSIONS: Minimally invasive incisional herniorrhaphy yielded an acceptable morbidity and recurrence rate during the follow-up period. The outcome compares favorably with that for open incisional hernia repair. Although long-term follow-up evaluation is desirable, the data support the contention that the minimally invasive approach is an appropriate option for incisional hernia.

Adult↗
PubMed2001

A primary burn wound does not slow the contraction rate of an adjacent excisional wound.

The response to major burn injury includes systemic release of mediators that may have an effect on wound healing. The authors evaluated the effect of a burn injury on the contraction of an excisional wound adjacent to the burn, and the effect of plasma derived from burn-injured animals on the contraction of the fibroblast-populated collagen matrix (FPCM). Nine rats (90-100 days old) under anesthesia received a standardized 40% total body surface area burn to the dorsum, and eight rats (controls) were sham burned. Immediately thereafter all animals had a square (2.25 cm2) of unburned dermis excised from the dorsum, superior to the burn wound. The excisional wound area was measured at 2 to 3-day intervals postoperatively. Plasma was collected from some animals on postburn day 15; the contraction-stimulating ability of burn vs. control plasma was measured in the FPCM. All animals remained free of sepsis. The excisional wound area in all animals decreased to 50% and then 25% of the initial area after approximately 4 and 8 days respectively. The rate of wound contraction (i.e., wound area reduction) did not differ between burn and control animals. Contraction stimulated by 5% plasma in the FPCM (expressed as a percentage of the original matrix area) was 70.2+/-6.4 (standard deviation) mm2 vs. 62.4 +/-3.9 mm2 for burn vs. control rats respectively (p>0.05). Burn injury in this model did not alter the contraction of an excisional wound at an unburned site. There was no significant difference in the contraction-stimulating ability (FPCM model) of plasma from the burned rats compared with plasma from unburned control rats. Burn injury appears to have an inconsequential effect on the contraction of an adjacent wound.

Animals↗
PubMed2000

[New developments in abdominal wall closure].

A perspective on the newer techniques and techniques and recommendations in abdominal wall closure as described in the English-language literature is given. Primary closure of midline incision with running suture should be performed with a suture length to wound length ratio in the range of 4-5 to 1; this appears to be the most important step the surgeon can take to avoid dehiscence and/or hernia. The choice of suture material does not appear to be crucial with regard to the prevention of wound failure. Anecdotal experience has suggested that the specific technique of mesh placement in incisional herniography is important to prevent recurrence. Difficult abdominal closure can be handled by one of a number of temporary abdominal closure techniques.

Abdominal Muscles↗
PubMed2000

An automated, handheld biosensor for aflatoxin.

A new immunoaffinity fluorometric biosensor has been developed for detecting and quantifying aflatoxins, a family of potent fungi-produced carcinogens that are commonly found in a variety of agriculture products. They have also been cited as a biological agent under weapons development. The handheld, self-contained biosensor is fully automatic, highly sensitive, quick, quantitative, and requires no special storage. Approximately 100 measurements can be made before refurbishment is required, and concentrations from 0.1 parts per billion (ppb) to 50 ppb can be determined in <2 min with a 1 ml sample volume. The device operates on the principles of immunoaffinity for specificity and fluorescence for a quantitative assay. The analytic procedure is flexible so that other chemical and biological analytes could be detected with minor modifications to the current device. Advances in electro-optical components, electronics, and miniaturized fluidics were combined to produce this reliable, small, and versatile instrument.

Aflatoxins↗
PubMed1999

Release of mechanical tension triggers apoptosis of human fibroblasts in a model of regressing granulation tissue.

In an in vitro model of granulation tissue, early passage human diploid fibroblasts under mechanical tension showed little or no apoptosis. Release of mechanical tension triggered an apoptotic response that occurred within 3-6 h and reached a plateau by 24 h. The percentage of apoptotic cells (approximately 15%) remained constant up to 7 days, and after 3 days, total cell number declined. Identification of mechanical unloading as a stimulus for apoptosis, without application of pharmacologic or genetic intervention, is a novel observation that permits us to model similar events that occur during wound healing. Studies on the mechanism regulating apoptosis under these conditions established that the apoptotic response does not require differentiation of cells into myofibroblasts but is governed by a combination of mechanical tension and growth factors in the collagen matrix.

Actins↗
PubMed1999

Laparoscopic repair of large hiatal hernia with polytetrafluoroethylene.

BACKGROUND: Several studies have shown that large hiatal hernias are associated with a high recurrence rate. Despite the problem of recurrence, the technique of hiatal herniorrhaphy has not changed appreciably since its inception. In this 3-year study we have evaluated laparoscopic hiatal hernia repair in individuals with a hernia defect greater than 8 cm in diameter. METHODS: A series of 35 patients with sliding or paraesophageal hiatal hernias was prospectively randomized to hiatal hernia repair with (n = 17) or without (n = 18) polytetrafluoroethylene (PTFE). All patients had an endoscopic and radiographic diagnosis of large hiatal hernia. Both repairs were performed by using interrupted stitches to approximate the crurae. In the group randomized to repair with prosthesis, PTFE mesh with a 3-cm "keyhole" was positioned around the gastroesophageal junction with the esophagus through the keyhole. The PTFE was stapled to the diaphragm and crura with a hernia stapler. RESULTS: Patients were followed with EGD and esophagogram at 3 months postoperatively, and with esophagogram every 6 months thereafter. Individuals with PTFE had a longer operation time, but the 2-day hospital stay was the same in both groups. The cost of the repair was $1050 +/- $135 more in the group with the prosthesis. There were two complications (1 pneumonia, 1 urinary retention) in the group repaired with PTFE and one complication (pneumothorax) in the group without prosthesis. The group without PTFE was notable for three (16.7%) recurrences within the first 6 months of surgery. CONCLUSION: On the basis of these preliminary results it appears that repair with PTFE may confer an advantage, with lower rates of recurrence in patients with large hiatal hernia defects.

Adult↗
PubMed1999

Laparoscopic prosthetic reinforcement of hiatal herniorrhaphy.

BACKGROUND/AIMS: Primary repair of a large hiatal hernia is associated with a published recurrence rate of up to 10%; anecdotal rates even higher than this have been reported to the authors. The use of prosthetic material in the repair of other abdominal wall defects has often produced better results than primary repair. We wanted to compare laparoscopic primary repair of large hiatus hernias with laparoscopic primary repair reinforced with prosthetic. METHODS: Thirty-one patients with symptomatic gastroesophageal reflux and a hiatal defect 8 cm or greater were randomized to Nissen fundoplication with posterior cruroplasty (n = 16) or Nissen cruroplasty, and onlay of polytetrafluoroethylene (PTFE) mesh (n = 15). All patients underwent preoperative esophagogastroduodenoscopy (EGD) and barium esophagography. After posterior cruroplasty with interrupted nonabsorbable suture, the mesh reinforcement group had an onlay of PTFE placed around the hiatus. A radial slit with 3 cm 'keyhole' (to accommodate the esophagus) was cut into the PTFE. The prosthetic was stapled to the diaphragm, and the two leaves of the slit were stapled to each other. All patients underwent EGD at 3 months and all had esophagrams every 6 months postoperatively. Follow-up ranged from 12 to 36 months. RESULTS: Length of hospital stay was equal in both groups (2 days). The average cost to the patient with PTFE was USD 1,050 higher than to the patient with primary repair. There were 2 complications (1 pneumonia, 1 urinary retention) in the PTFE group, and 1 complication (pneumothorax) in the primary repair group. There were 3 recurrences (18.8%) in the primary group (p = 0.08, chi(2) test). CONCLUSION: The use of PFTE reinforcement for primary repair of large hiatal hernias may result in a lower rate of recurrent herniation compared to primary repair alone.

Adult↗
PubMed1998

Management of intrathoracic stomach with polypropylene mesh prosthesis reinforced transabdominal hiatus hernia repair.

BACKGROUND: Posterior cruroplasty repair of a large paraesophageal hiatus hernia has a higher than desirable rate of recurrence attributable to the inexorable cyclic negative intrathoracic pressure of respiration and positive intraabdominal pressure produced by straining, physical exertion, and coughing. To reduce the risk of recurrence after repair of a large hiatus hernia and intrathoracic stomach, we have used posterior cruroplasty reinforced with an onlay polypropylene mesh prosthesis. This paper reviews the feasibility of this technique. STUDY DESIGN: We did a retrospective review of 44 patients with large hiatus hernia and intrathoracic stomach who had posterior cruroplasty and onlay of polypropylene mesh prosthesis applied to the crura and adjacent diaphragm to repair the hiatal defect. RESULTS: Preoperative symptoms (mean duration, 26 months) included pain (33 patients), vomiting (21), dysphagia (19) and anemia (8). The typical patient (28 men and 16 women, mean age, 60) had two-thirds or more of the stomach above the diaphragm. Organoaxial gastric volvulus and herniated large or small bowel were present in 10 and 9 patients, respectively. A gastrostomy was performed for temporary drainage in 38 patients in addition to the hernia repair; 11 patients underwent a concomitant Nissen fundoplication. Postoperative complications included pleural effusion (four patients), atrial dysrhythmia (three patients), and superficial wound infection (two patients). Mean followup for 43 patients was 52 months. There have been no clinical recurrences. CONCLUSIONS: Mesh prosthesis reinforced hiatus hernia repair is effective, appears to have a low clinical recurrence rate, and should be an option in the treatment of a large hiatus hernia with intrathoracic stomach.

Adult↗
PubMed1997

Prosthetic reinforcement of posterior cruroplasty during laparoscopic hiatal herniorrhaphy.

Symptomatic gastroesophageal reflux after Nissen fundoplication may occur if the wrap herniates into the thorax. In an attempt to prevent recurrent hiatal hernia we employed polytetrafluoroethylene (PTFE) mesh reinforcement of posterior cruroplasty during laparoscopic Nissen fundoplication and hiatal herniorrhaphy. Three patients with symptomatic gastroesophageal reflux and a large (>==8 cm) hiatal defect underwent laparoscopic posterior cruroplasty and Nissen fundoplication. The cruroplasty was reinforced with a PTFE onlay. No perioperative complications occurred, and in follow-up (<==11 months) the patients are doing well. When repairing a large defect of the esophageal hiatus during fundoplication, the surgeon may consider reinforcement of the repair with PTFE mesh.

Fundoplication↗
PubMed1997

Canine intestinal myoelectric activity after open versus laparoscopically assisted right hemicolectomy.

BACKGROUND: It is a common belief that a laparoscopic procedure results in a shorter duration of postoperative ileus compared with the equivalent open procedure. This study was undertaken to determine whether laparoscopically assisted right hemicolectomy in the dog results in a shorter duration of ileus compared with open right hemicolectomy. METHODS: Eight bipolar serosal electrodes (4 on the small bowel, 4 on the left colon) were implanted in each dog (n = 10). Three weeks after electrode implantation baseline recording was made for 5 days; then 5 dogs underwent laparoscopically assisted right hemicolectomy and 5 underwent open right hemicolectomy. Myoelectric activity was recorded continuously for 72 hours postoperatively. Tracings were analyzed for the time of reappearance, duration, migration velocity, and cycle length of phase 2, phase 3, and the migrating colonic complex. The criteria used for the resolution of postoperative ileus were the return of phase 2, phase 3, and the migrating colonic complex. RESULTS: All dogs had temporary loss of organized myoelectric activity postoperatively. The mean reappearance time (minutes +/- standard deviation) for phase 3 was 857 +/- 574 versus 761 +/- 600; the phase 2 reappearance time was 1,845 +/- 610 versus 1,590 +/- 668; and the migrating colonic complex reappearance time was 534 +/- 365 versus 572 +/- 552, open versus laparoscopically assisted right hemicolectomy, respectively. The times were not different (Wilcoxon rank sum test, P > 0.05). The time required for phase 3, phase 2, and the migrating colonic complex to attain preoperative configuration also was not different between the open and laparoscopically assisted group. CONCLUSION: Myoelectric resolution of postoperative ileus did not occur earlier in the dog undergoing laparoscopically assisted right hemicolectomy compared to the dog undergoing open right hemicolectomy. This data does not support the hypothesis that a laparoscopically assisted colectomy results in a shorter duration of postoperative ileus than the equivalent open procedure.

Animals↗
PubMed1997

Urinary adenosine excretion in patients receiving amphotericin B.

BACKGROUND: Intravenous amphotericin B (AMB) administration in animals causes renal vasoconstriction, ischemia, and oliguria that may result in irreversible renal injury; the mechanism of AMB nephrotoxicity may be similar in human beings. Adenosine is excreted in urine by the ischemic kidney. We hypothesized that adenosine excretion and oliguria would be a marker for patients who later would manifest AMB-associated renal insufficiency and that pre-AMB saline administration (which ameliorates AMB nephrotoxicity) would negate the change in adenosine excretion and urine output. METHODS: Twenty hospitalized patients being treated at the direction of their attending physician and who were receiving AMB (15 to 75 mg intravenously) had urine collected for 1 hour before and for 2 hours during AMB infusion. Eleven patients received normal saline solution (500 ml intravenously) before the AMB infusion; the other nine formed the comparator group. An aliquot of each urine collection was precipitated with perchloric acid to remove protein and cellular elements and centrifuged, and the supernatant was assayed for adenosine by using high-pressure liquid chromatography. RESULTS: Infusion of AMB was associated with a decrease in mean urine output both in patients who received saline solution (245 before versus 149 ml/hr during AMB infusion, p = 0.04) and in patients in comparator group (139 versus 89 ml/hr, p = 0.027). The mean urinary adenosine excretion was unchanged in the saline-loaded group (0.1354 before versus 0.1255 mmol/hr during drug infusion, p = 0.25) and was decreased in the comparator group (0.2276 versus 0.1127 mmol/hr, p = 0.01). Development of renal insufficiency did not correlate with the change in urine output or adenosine excretion. CONCLUSIONS: AMB infusion in human beings results in decreased urine output and decreased adenosine excretion. The latter effect is prevented by a pre-AMB saline load. The changes in urine output and adenosine excretion are not predictive of the development of renal insufficiency.

Adenosine↗
PubMed1997

Acute wound failure.

The causes and treatment of acute failure of the abdominal incision are reviewed, along with a summary of studies on fascial healing. Emphasis is placed on taking large bites of tissue during closure to prevent dehiscence. Patient-related risk factors are viewed as less important in the causation of wound failure.

Abdomen↗
PubMed1997

Minimally invasive ventral herniorrhaphy.

Three types of minimally invasive ventral herniorrhaphies were performed in eight patients: primary repair with sutures (1 case), single-layer prosthesis repair with polytetrafluoroethylene (4 cases), and bilayer prosthesis repair with polytetrafluoroethylene and polypropylene (3 cases). One patient undergoing the bilayer repair developed a small hematoma in the subcutaneous tissue at the site of the repair, which resolved without intervention. There were no other complications, and no recurrence was noted in follow-up of 14 to 20 months.

Follow-Up Studies↗