Biomedical subjects

Mark A Carlson

Publications and source records attributed to Mark A Carlson.

5 recordsLinked to original sources

PubMed2003

Wound splinting regulates granulation tissue survival.

PURPOSE: Fibroblast survival within an in vitro collagen matrix is dependent on matrix anchorage to a rigid substratum. The purpose of this study was to determine whether granulation tissue survival in vivo also is dependent on matrix anchorage. We hypothesized that splinting an excisional wound (i.e., anchoring the wound edges) would promote granulation tissue survival and that desplinting a splinted wound would produce granulation tissue apoptosis. METHODS: Eighteen Wistar rats (3 months, 350 g) underwent excisional wounding (2 x 2 cm, dorsal skin) with immediate wound splinting (a metal template affixed with sutures) on day 0. On day 6, rats (n = 6 per group) underwent splint removal (desplinted), splint removal with circumferential incision of the wound edge (desplint/release), or no intervention (splinted); sacrifice of all animals was on day 7. Frozen sections of granulation tissue were stained with TUNEL or H and E; data were analyzed with ANOVA and the unpaired t test. RESULTS: The cross-sectional and surface area of the desplinted and desplint/release granulation tissue both decreased compared to the splinted granulation tissue (*P < 0.05). The nuclear density of the desplint/release granulation tissue was 25% less compared to the splinted granulation tissue (*P < 0.05). The desplinted and desplint/release apoptotic rates were twice and >10x greater than the splinted apoptotic rate, respectively (*P < 0.05). CONCLUSIONS: The rate of cell death in a splinted wound (an in vivo equivalent of an anchored FPCM) is minimal to nil, which is consistent with our hypothesis. Desplinting and releasing the wound edge of a previously splinted wound (the in vivo equivalent of a detached FPCM) results in granulation tissue regression and a large increase in apoptosis. Desplinting a wound alone results in changes somewhat intermediate to the splinted and desplint/release conditions. Loss of wound anchorage acutely promotes granulation tissue apoptosis.

Animals↗

PubMed2003

Selective use of esophageal manometry and 24-Hour pH monitoring before laparoscopic fundoplication.

BACKGROUND: Preoperative esophageal manometry and 24-hour pH monitoring commonly are used in preoperative evaluation of patients undergoing fundoplication. Here we review our experience with the selective preoperative workup of patients undergoing fundoplication to treat gastroesophageal reflux disease. STUDY DESIGN: A series of 628 consecutive antireflux procedures was reviewed. History and physical examination, upper endoscopy, and upper gastrointestinal videofluoroscopy were obtained preoperatively on all patients; the first 30 patients also underwent esophageal manometry and pH monitoring (routine evaluation group). Thereafter, pH monitoring only was performed for atypical reflux symptoms, and manometry only was performed for a history of dysphagia, odynophagia, or for abnormal motility on videofluoroscopy (selective evaluation group). All patients underwent a laparoscopic floppy Nissen fundoplication, and then endoscopy and fluoroscopy at 3 months and 12 months postoperatively. RESULTS: Eighty-five of the patients in the selective evaluation group (14%) required manometry, and 88 (15%) underwent pH monitoring. Eighteen of the 115 patients who underwent manometry (16%) had evidence of dysmotility. None of these 18 patients had increased dysphagia postoperatively; 8 of 18 reported improvement with swallowing. Five patients in the selective group (0.8%) had persistent postoperative dysphagia caused by technical error (four patients) or with no identifiable cause (one patient). The estimated charge or collection reduction with use of the selective evaluation was 1,253,100 US dollars or 395,000 US dollars, respectively. CONCLUSIONS: Selective use of manometry and pH monitoring was cost effective and safe in this series. Although esophageal manometry and 24-hour pH monitoring might be necessary with abnormal findings on videofluoroscopy or atypical symptoms, in our experience, their routine use is not essential in preoperative evaluation of patients undergoing fundoplication for gastroesophageal reflux disease.

Adolescent↗

PubMed2002

A prospective, randomized trial of laparoscopic polytetrafluoroethylene (PTFE) patch repair vs simple cruroplasty for large hiatal hernia.

HYPOTHESIS: Large hiatal hernias are prone to disruption, resulting in reherniation, when repaired with simple cruroplasty. The use of mesh may decrease the rate of reherniation in the laparoscopic repair of large hiatal hernias. DESIGN: Prospective, randomized controlled trial. SETTING: University-affiliated private hospital. PATIENTS: Seventy-two individuals undergoing laparoscopic Nissen fundoplication with a hernia defect greater or equal to 8 cm in diameter. INTERVENTION: Nissen fundoplication with posterior cruroplasty (n = 36) vs Nissen fundoplication with posterior cruroplasty and onlay of polytetrafluoroethylene (PTFE) mesh (n = 36). MAIN OUTCOME MEASURES: Recurrences, complications, hospital stay, operative time, and cost. RESULTS: Patients in both groups had similar hospital stays, but the PTFE group had a longer operative time. The cost of the repair was $960 +/- $70 more in the group with the prosthesis. Complications were minor and similar in both groups. There were 8 hernia recurrences (22%) in the primary repair group and none in the PTFE group (P<.006). CONCLUSION: The use of prosthetic reinforcement of cruroplasty in large hiatal hernias may prevent hernia recurrences.

Adult↗

PubMed2002

Granulation tissue regression induced by musculocutaneous advancement flap coverage.

BACKGROUND: Clinical experience suggests that granulation tissue may be inhibited by coverage with a musculocutaneous flap. We hypothesized that coverage of an open wound with a musculocutaneous flap would result in regression and apoptosis of the wound's granulation tissue. METHODS: In the first experiment, 32 rats underwent excisional wounding; 16 underwent musculocutaneous flap coverage of their granulation tissue on postwounding day 8, and then 16 rats (8 controls + 8 flaps) were killed on both postwounding days 10 and 12 (2 and 4 days after the flap procedure, respectively). In the second experiment, 18 rats were wounded, and on postwounding day 5 the rats underwent flap coverage (n = 6), wound edge release/mobilization (the first step of the flap procedure) without flap coverage (n = 6), or dressing change only (n = 6); all rats were killed on postwounding day 6 (24 hours after the secondary intervention). Apoptosis was quantified with the terminal deoxynucleotidyl transferase-mediated nick-end labeling assay. RESULTS: Placement of a musculocutaneous flap over an 8-day-old excisional wound in the first experiment increased the apoptotic rate in the granulation tissue from 0% to 1% (controls) to 5% to 10% at both 2 and 4 days after flap coverage (P <.05). Cell population density decreased 50% in the flap-covered granulation tissue compared with the controls (P <.05). In the second experiment, circumferential release of the granulation tissue resulted in an equivalent increase in granulation tissue apoptosis over controls compared to that induced by the full flap procedure. CONCLUSIONS: Coverage of established granulation tissue with a musculocutaneous flap resulted in histologic regression of the wound's granulation tissue after 2 to 4 days of flap coverage and induced at least a 5-fold increase in the apoptotic rate of the granulation tissue. Releasing the wound edge increased granulation tissue apoptosis to a level equivalent to that produced by the musculocutaneous flap procedure, suggesting that alteration of the wound's mechanical environment is responsible for the acute induction of apoptosis in this model.

Animals↗

PubMedDate not supplied

Robotically assisted endoscopic ovarian transposition.

BACKGROUND: Ovarian transposition is the anatomical relocation of the ovaries from the pelvis to the abdomen. Transposition is beneficial in women who are to undergo pelvic radiation, because it allows maintenance of ovarian function and preservation of assisted reproductive capacity. METHODS: The da Vinci surgical system (Intuitive Surgical, Mountainview, CA, USA) was used to perform an endoscopic ovarian transposition. The ovaries were mobilized on their respective infundibulopelvic ligaments and sutured to the ipsilateral pericolic gutters. RESULTS: A series, of laboratory sessions using the da Vinci system was completed at our institution's training facility. Surgical experience included cadaveric pelvic dissection and abdominopelvic procedures on anesthetized porcine models. Additional didactic and laboratory training, including a certification examination, was obtained from Intuitive Surgical, Inc. The first clinical case of robotically assisted endoscopic ovarian transposition was performed. CONCLUSIONS: Robotically assisted endoscopy was successfully used for ovarian transposition.

Adult↗