Sebastian G. de la Fuente

Clinical application of porcine small intestinal submucosa in the management of infected or potentially contaminated abdominal defects

The repair of abdominal wall defects in potentially contaminated or grossly infected fields presents a difficult clinical problem. Polypropylene mesh is relatively contraindicated in these settings because of the potential for chronic infection. The alternatives to polypropylene include polyglactin mesh, which is not associated with chronic infection but is associated with a 100% recurrence of hernia. The ideal prosthetic for this patient group should be resistant to infection and ensure a low rate of hernia recurrence. We studied the use of small intestinal submucosa, which has been reported to be resistant to infection and incorporates into the fascia over 3 to 6 months, in 20 patients with ventral or inguinal hernias (18 ventral, 2 inguinal hernia) in the setting of bacterial contamination. The early postoperative complication rate was 50%. One patient with fasciitis had degradation of the small intestinal submucosa and loss of the bioprosthesis within 7 days. Other early complications included seroma (n = 2), ileus (n = 1), and wound infection (n = 8). No patient experienced chronic infection. Mean follow up was 15.7 months and the rate of recurrence documented by CT or physical examination was 30%. We concluded the following: (1) small intestinal submucosa is an effective alternative bioprosthesis in the management of ventral/inguinal hernia when there is associated bacterial contamination; (2) human vs. pig immune response has not been seen in this patient population; (3) early graft failure due to overwhelming fascial infection was noted in one patient and may be a limitation of this technology in a minority of patients; and (4) early hernia recurrence is relatively low but long-term follow-up has not been completed.

Evaluation of porcine-derived small intestine submucosa as a biodegradable graft for gastrointestinal healing.

High-risk anastomoses in the gut may benefit from the application of a synthetic reinforcement to pre vent an enteric leak. Recently a porcine-derived small intestine submucosa (SIS) was tested as a bioscaffold in a number of organ systems. The aim of this study was to evaluate the effectiveness of SIS in stimulating healing in the stomach. Twelve rats underwent surgical removal of a full-thickness gastric defect (1 cm) and subsequent repair with a double-layer patch of porcine-derived SIS. The graft was secured with interrupted sutures placed within 1 mm of the edge of the graft. After 21 days, the animals were killed and their stomachs harvested for histologic examination. Cross sections were processed for paraffin embedding and 4-micron sections were stained with hematoxylin and eosin. All animals survived, gained weight, and demonstrated no signs of peritonitis over the 3-week postoperative period. On postmortem examination, the defect was completely closed in all animals by granulation tissue and early fibrosis. Although most of the luminal surface of the grafted areas remained ulcerated, early regeneration of normal gastric mucosa was seen at the periphery of the defect. SIS may act as an effective scaffolding agent for intestinal mucosa and may offer protection in high-risk anastomoses.

Neoadjuvant Chemoradiation for Rectal Cancer Reduces Lymph Node Harvest in Proctectomy Specimens

PurposeThe purpose of this study was to compare the number of lymph nodes retrieved following proctectomy for rectal cancer in patients either receiving no neoadjuvant therapy versus those treated with standard preoperative chemoradiation.MethodsA retrospective review was performed of all consecutive patients that underwent proctectomy for rectal cancer from 1997–2006. Specimens from patients that received neoadjuvant therapy were compared to patients that did not receive preoperative chemoradiation.ResultsOf a total of 286 patients, 188 received neoadjuvant therapy and 88 did not. More patients with stage II or higher cancers received neoadjuvant therapy. Overall, fewer neoadjuvant patients underwent an anastomotic procedure than the no neoadjuvant group (17% vs. 7% APR). Significantly fewer total lymph nodes were retrieved in the neoadjuvant therapy patients compared to those who did not receive preoperatively therapy (Neo 14.6 ± 0.6 vs. No-Neo 17.2 ± 1.1, p < 0.029).ConclusionsStandard neoadjuvant therapy significantly decreases the number of lymph nodes retrieved following proctectomy for patients with rectal cancers. Quality initiatives or performance measures evaluating lymph node harvest following proctectomy should reflect the use of preoperative chemoradiation.

Inhibition of the vanilloid receptor subtype-1 attenuates TNBS-colitis

Primary sensory neurons are important in regard to the initiation and propagation of intestinal in.ammation. The vanilloid receptor subtype-1 (VR-1) is a cation channel located on the sensory nerves that, when stimulated, release proinflammatory peptides. Previous reports have indicated that inhibition of VR-1 with capsazepine (CPZ), a VR-1 antagonist, attenuates dextran sodium sulfate (DSS) colitis in rats. DSS-induced colitis resembles ulcerative colitis with regard to its pathologic features. In this study, we examined the effect of CPZ on trinitrobenzene sulfonic acid (TNBS)-induced colitis, an experimental model of intestinal inflammation that most closely resembles the histologic and microscopic features of Crohn’s disease. Colitis was induced by administering a single enema of 100 mg/ kg TNBS in 50% ethanol via catheter to lightly anesthetized rats. Subsets of rats were treated with either 1 μmol/kg/ml of CPZ or CPZ-vehicle via enema for 6 days. Seven days after TNBS administration, rats were sacrificed and inflammation was assessed using a validated macroscopic damage score (MDS) and by measuring myeloperoxidase (MPO) activity. In addition, histologic examination was performed. TNBS administration resulted in reproducible chronic erosive lesions extending into the muscularis propria and extensive recruitment of neutrophils in the distal colon. MDS and MPO scores were considerably elevated in the TNBS colons when compared with the TNBS vehicle animals. TNBS rats treated with CPZ enemas exhibited a substantial reduction in MDS and MPO scores and demonstrated dramatically improved pathologic findings. Topical CPZ resulted in considerable attenuation of TNBSinduced colitis. These results support the role of VR-1 and sensory neurons with regard to intestinal inflammation.

Incidence of benign disease in patients that underwent resection for presumed pancreatic cancer diagnosed by endoscopic ultrasonography (EUS) and fine-needle aspiration (FNA)

IntroductionThe lack of accurate markers makes preoperative differentiation between pancreatic cancer and non-malignant head lesions clinically challenging. In this study, we investigated the incidence of benign disease in patients that underwent resection for presumed pancreatic cancer diagnosed by EUS and EUS-guided FNA.MethodsMedical records of consecutive patients who underwent pancreaticoduodenectomy at Duke University were reviewed. Demographics, clinicopathologic characteristics, preoperative imaging, EUS, EUS-guided FNA, and postoperative outcomes were analyzed.ResultsSeven percent of the total 494 patients studied were found to have benign disease on postoperative pathology. Fifty-nine percent of these patients with benign disease underwent preoperative EUS. EUS was positive for a head mass in 70%, demonstrated enlarged lymph nodes in 27%, and showed signs concerning for vascular invasion in 13%. FNA was suspicious or indeterminate for cancer in 63% of patients. Postoperative complications occurred in 47% and one patient died after surgery. The overall pancreatic leak rate was 15%.ConclusionsEven with aggressive use of preoperative evaluation, there is still a small subset of patients where malignancy cannot be excluded without pancreaticoduodenectomy.

Preoperative Immune Status Determines Anal Condyloma Recurrence After Surgical Excision

AbstractPURPOSE: Immunosuppression is an important risk factor for anal condyloma progression; however, its effects on postoperative outcomes remain unclear. In the present study, we investigated risk factors and recurrence rates in immunocompromised patients requiring surgery for medically intractable anal condyloma. METHODS: A retrospective review was performed on 63 consecutive patients who underwent surgical intervention for medically intractable anal condyloma at a single institution. Patient cohorts included immunosuppressed patients (e.g., HIV-seropositive, leukemia, idiopathic lymphopenic syndrome, or transplant patients; n = 45) and immunocompetent patients (n = 18). Recurrence rates and time to recurrence after surgery were determined for both groups. Preoperative CD4 count and viral load within the HIV subpopulation were also determined. The majority of the patients were male (90 percent), with a median age of 36 years. RESULTS: Anal condyloma recurred in 66 percent of the immunosuppressed patients compared with 27 percent of the immunocompetent group. Recurrence time expressed in months was shorter in immunosuppressed patients than in immunocompetent patients (6.8 ± 1.5 vs. 15 ± 5.7 months; P < 0.05). In the subpopulation of HIV-seropositive patients, no association was found between recurrence rates and viral loads; however, CD4 counts were significantly lower in those who had recurrence than in those who did not (226 ± 31.7 vs. 401 ± 51.2 cells/μl; P < 0.05). CONCLUSIONS: After surgery, anal condyloma in immunosuppressed patients recurs significantly more often and within a shorter period of time than in patients with a competent immune system. Additionally, in HIV-seropositive patients, CD4 counts should be maximized to prevent early recurrence of anal condyloma.

Pre- and intraoperative variables affecting early outcomes in elderly patients undergoing pancreaticoduodenectomy

BACKGROUND Conflicting data exist regarding the safety of pancreatic resections in elderly patients. In this study we compared early complication and mortality rates between patients younger and older than 80 years of age who underwent pancreaticoduodenectomy using a validated national database. METHODS The National Surgical Quality Improvement Program (NSQIP) database for 2005-2009 was used for this retrospective analysis. The primary outcome measures for our analysis were 30-day postoperative mortality, major complication rate and overall complication rate. RESULTS A total of 6293 patients who underwent PD for any cause were included in the analysis. Of these, 9.4% were aged ≥80 years. The incidence of 30-day mortality was significantly higher in patients aged ≥80 years (6.3%) than in those aged <80 years (2.7%). Older patients were also noted to have higher rates of overall complications and serious complications. On multivariate analysis, age, ASA (American Society of Anesthesiologists) classification, reduced functional status, history of dyspnoea, and need for intraoperative transfusion were risk factors associated with the occurrence of overall complications, serious complications and postoperative mortality. CONCLUSIONS This study shows that age among other factors is a determinant of postoperative morbidity and mortality following PD.

A review of laparoscopy for non-obstetric-related surgery during pregnancy.

PURPOSE Similar to the general population, parturients (and their fetuses) could benefit from the reduced manipulation associated with laparoscopy. The purpose of this article is to review the current state of knowledge (both clinical and experimental) with respect to the fetal effects of maternal laparoscopy for non-obstetric-related surgery during pregnancy. METHODS Human and experimental animal results are examined, and we present preliminary data from our own laboratory. CONCLUSIONS Future experiments are proposed to further develop and refine standards of care for general surgeons and obstetricians who are presented with gravid females in abdominal distress.

Maternal Insufflation during the Second Trimester Equivalent Produces Hypercapnia, Acidosis, and Prolonged Hypoxia in Fetal Sheep

Background:Anecdotal reports suggest that the second trimester is the safest time to conduct a laparoscopic procedure on a pregnant patient, but this supposition has not been tested empirically. Methods:Previously instrumented preterm sheep (total n = 8) at gestational day 90 (term, 145 days) were anesthetized and then insufflated with carbon dioxide for 60 min at a pressure of 15 mmHg. Cardiovascular parameters were continuously recorded while blood gas status was determined before and at 15-min intervals during and up to 2 h after insufflation. Results:Insufflation produced minimal maternal blood gas or cardiovascular changes except for a significant reduction in uterine blood flow. The decrease in perfusion increased fetal arterial blood partial pressure of carbon dioxide and decreased fetal pH, oxygen saturation, and oxygen content; there was also progressive fetal hypotension and bradycardia. After manually deflating the ewe, uterine blood flow returned to normal, and the fetal partial pressure of carbon dioxide and pH changes resolved within 1 h. However, fetal oxygen saturation and content remained depressed, and fetal cardiovascular status continued to decline during the 2-h postinsufflation monitoring period. Conclusion:Previous studies with near-term sheep determined that carbon dioxide pneumoperitoneum produces respiratory acidosis but does not decrease fetal oxygenation. In contrast, the current findings indicate that in the preterm fetus, insufflation-induced hypercapnia and acidosis are accompanied by prolonged fetal hypoxia and cardiovascular depression. This result suggests that additional work should be conducted to confirm the presumed safety of conducting minimally invasive procedures during the second trimester.

A Description of the Preterm Fetal Sheep Systemic and Central Responses to Maternal General Anesthesia

BACKGROUND: The second trimester is recommended as the optimal time to conduct a surgical procedure on pregnant patients, even though the fetal responses to anesthesia at this age are not known. Here we assessed the responses of preterm fetal sheep to a standard anesthetic regimen of midazolam, thiopental, and isoflurane. METHODS: Variables were monitored in previously instrumented preterm pregnant sheep before, during, and after 4 h of general anesthesia. Isoflurane produced moderate fetal hypotension and bradycardia, whereas extubation was accompanied by increases in fetal heart rate and mean arterial blood pressure. RESULTS: We observed an initial increase in fetal Sao2 followed by a gradual decline to baseline. Within the fetal brain, oxygenated hemoglobin changed by <10% (nonsignificant) and deoxygenated hemoglobin and total hemoglobin varied by <5%. Overall, although O2 levels within the preterm fetal brain were not independently enhanced by isoflurane (as occurs in the older fetus and in the adult), they did remain constant even as fetal mean arterial pressure decreased by more than 20%. By extension, we failed to identify changes in cerebral oxygenation that could be construed as injurious. CONCLUSION: Any adverse preterm fetal response to maternal surgery should not be attributed solely to the actions of general anesthesia upon the fetus.