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Biomedical subjects

A E Ortega

Publications and source records attributed to A E Ortega.

At least 19 recordsLinked to original sources
PubMed2001

The WAND local anesthetic delivery system: a more pleasant experience for anal anesthesia.

PURPOSE: The WAND is a computer-controlled local anesthetic delivery system. Its use has been proven to be more comfortable for dental patients. The purpose of this study is to explore its applicability to anal procedures. Our hypothesis is that the WAND will provide greater comfort during anesthesia delivery while achieving the same anesthetic effect as traditional syringe technique. METHODS: Twenty patients with painless anal pathology were randomized to receive anal anesthesia using either the WAND or traditional syringe technique to a randomly selected half of the anoderm (right or left). The opposite side was then anesthetized by the alternate method, allowing patients to act as their own control. Objective and subjective pain scores were obtained from the patient after each mode of delivery. An independent observer interpreted the patient's tolerance by giving a subjective pain score. The volume of anesthetic used was recorded. Adequacy of anesthesia was tested by a pinch test. RESULTS: Sixteen (80 percent) of the 20 patients preferred the use of the WAND. Objective and subjective pain scores per the patients and subjective pain scores per the observer were significantly lower for the WAND than for traditional syringe technique (P < 0.05). The mean volume of local anesthetic used with the WAND was 1.7 ml compared with 3.2 ml for traditional syringe technique (P < 0.005). Anesthesia achieved with the WAND was as good as that achieved with traditional syringe technique when the pinch test was used. CONCLUSION: The WAND is as effective as the traditional syringe technique in the delivery of anal anesthesia while providing a more comfortable experience for the patient.

Adult↗
PubMed1998

New technique for mesh repair of paracolostomy hernias.

Paracolostomy hernias are common and require treatment when symptomatic. Traditional methods of repair have high recurrence rates. We describe a new technique using polytetrafluoroethylene mesh, which offers preservation of stoma site, lack of recurrences, ease, and safety.

Colostomy↗
PubMed1997

Variations in treatment of rectal cancer: the influence of hospital type and caseload.

PURPOSE: Surgical options for the treatment of rectal cancer may involve sphincter-sparing procedures (SSP) or abdominoperineal resection (APR). We sought to examine variations in the surgical treatment of rectal cancer for a large, well-defined patient population and specifically to determine if differences exist in management and survival based on hospital type and surgical caseload. METHODS: The Cancer Surveillance Program database for Los Angeles County was used to retrospectively retrieve data on all patients who underwent SSP or APR for rectal adenocarcinoma between 1988 and 1992. RESULTS: A total of 2,006 patients with adenocarcinoma of the rectum underwent SSP or APR during the study period. Overall, 55 percent underwent SSP, and the remaining 45 percent underwent APR. Use of SSP remained relatively constant for each year of the five-year period. Substantial variability was seen in the use of SSP at various hospital types. For localized disease, this varied from as low as 52 percent at teaching hospitals to as high as 78 percent at hospitals approved by the American College of Surgeons (P = 0.067). To examine the role of caseload experience, hospitals were divided into those completing an average of five or fewer rectal cancer cases per year vs. those completing an average of more than five cases per year. For localized disease, hospitals with higher caseloads performed SSP in significantly more cases, 69 vs. 63 percent (P = 0.049). Survival was seen to be significantly improved for patients operated on at hospitals with higher caseloads, in cases of both localized and regional diseases (P < 0.001). CONCLUSION: Surgical choices in the treatment of rectal cancer may vary widely, even in a well-defined geographic region. Although the reasons for this variability are multifactorial, hospital environment and surgical caseload experience seem to have a significant role in the choice of surgical procedure and on survival.

Adenocarcinoma↗
PubMed1996

Intraabdominal abscesses following laparoscopic and open appendectomies.

BACKGROUND: The purpose of this review was to evaluate the incidence of postoperative intraabdominal abscess formation following laparoscopic and open appendectomies. METHODS: The current study retrospectively examines appendectomies performed during the period from January 1993 to July 1994. Excluded were cases which were started laparoscopically but converted to open procedures. There were 1,287 cases identified; 597 were perforated (46%), 114 were gangrenous (9%), and 576 were acute (45%). These diagnoses represent intraoperative diagnoses. RESULTS: Of the 576 appendectomies for acute appendicitis, 64 (11%) were performed laparoscopically. There were four intraabdominal abscesses (0.7%), all occurring after open procedures. Of the 114 appendectomies for gangrenous appendicitis, 16 (14%) were done laparoscopically. There were two postoperative abscesses (1.8%), one following an open and one following a laparoscopic procedure. There was no significant difference in abscess rate between laparoscopic and open appendectomies for either acute or gangrenous appendicitis. Of the 597 appendectomies for perforated appendicitis, 28 (5%) were done laparoscopically. There were 19 postoperative abscesses in the whole group, accounting for a 3.2% abscess rate. Sixteen abscesses occurred after open appendectomies and three occurred after laparoscopic appendectomies (2.9% vs 11%, P = 0.054). The preoperative diagnosis was incorrectly identified as acute appendicitis in 95 cases subsequently found to have perforated appendicitis; there was only 1 postoperative abscess in this group. There was no difference in postoperative stay in the open vs laparoscopic group (6.3 days vs 6.1 days). CONCLUSIONS: We found no significant difference in the rate of postoperative intraabdominal abscess formation between laparoscopic and open appendectomies in cases of acute or gangrenous appendicitis. However, laparoscopic appendectomy for perforated appendicitis was associated with an important trend toward a higher rate of postoperative intraabdominal abscess formation than open appendectomy. This observation calls for closer prospective scrutiny of laparoscopic appendectomy in the setting of perforated appendicitis.

Abdominal Abscess↗
PubMed1996

Inferior vena caval blood flow and cardiac hemodynamics during carbon dioxide pneumoperitoneum.

BACKGROUND: The effects of carbon dioxide pneumoperitoneum on venous return and cardiac hemodynamics during laparoscopic surgery were studied. METHODS: Twelve adult pigs underwent placement of an electromagnetic flow meter across the infrarenal vena cava (IVC) as well as placement of Swan Ganz and arterial monitoring catheters. Measurements of the flow through infrarenal IVC, cardiac output (CO), pulmonary capillary wedge pressure (PCWP), mean arterial pressure (MAP), and heart rate were recorded at baseline, 5 and 60 min following insufflation to 15 mmHg with CO2, and 5 min following desufflation. Stroke volumes and systemic vascular resistance (SVR) were calculated as well. RESULTS: Flow through the IVC dropped by 24 and 31% at 5 and 60 min (p = 0.03 and 0.02, respectively). Paradoxically, cardiac output rose by 14 and 28% at 5 and 60 min (p = 0.03 at 60 min). Central venous and pulmonary capillary wedge pressures rose transiently by 35 and 36% at 5 min before returning to baseline (p < 0.01). Mean arterial pressure and heart rate remained relatively constant during insufflation. Systemic vascular resistance diminished from 938 dynes/cm/s prior to insufflation to its nadir at 60 min of 650 dynes/cm/s (p < 0.01). CONCLUSIONS: These observations suggest potentially complex interactions between the mechanical and systemic effects of the CO2 pneumoperitoneum on venous return. Transient elevations in cardiac filling pressures occur by an unknown mechanism, and a generalized enhanced inotropic state mediated via increased sympathetic outflow is observed in this hypercapnic anesthetized animal model.

Animals↗
PubMed1996

Necrotizing fasciitis following laparoscopic surgery. Case report and review of the literature.

Necrotizing fasciitis is a rare and potentially fatal infection characterized by rapid and progressive involvement of the fascia and subcutaneous tissues. Early diagnosis, aggressive initial debridement followed by planned redebridements in conjunction with nutritional support and antibiotics remain the mainstay of therapy. We present a case of necrotizing fasciitis of the abdominal wall following a laparoscopically assisted vaginal hysterectomy. Literature is reviewed and discussed with reference to this catastrophic infection in the age of laparoscopic surgery.

Abdominal Muscles↗
PubMed1996

Wound recurrence following laparoscopic colon cancer resection. Results of the American Society of Colon and Rectal Surgeons Laparoscopic Registry.

INTRODUCTION: Multiple case reports have suggested that laparoscopic resection of colon cancer may alter the pattern or incidence of cancer recurrence. All reports lack a significant denominator to evaluate the incidence of surgical wound recurrence. We hypothesized that wound recurrence incidence is not increased by laparoscopic resection of colon cancer. METHODS: A prospective registry was initiated under the auspices of The American Society of colon and Rectal Surgeons, American College of Surgeons, and Society of American Gastrointestinal Endoscopic Surgeons in 1992. Patients having laparoscopic colon resection were voluntarily entered and followed until June 1995. Recurrences were evaluated by the primary surgeon and reported to the registry. RESULTS: A total of 504 patients treated for cancer were identified in the registry. A minimum follow-up of one year was obtained for 480 of 493 evaluable patients (97.4 percent). Wound recurrence was identified in five patients (1.1 percent). Recurrence status was unknown in 18 patients (3.8 percent). CONCLUSION: Wound recurrence rates appear to be low. Although length of follow-up is limited, patterns of recurrence from previous studies suggest that 80 percent of recurrences should have occurred within one year. Given the limitations of a Phase II study, the hypothesis that recurrence rate is low is supported. However, prospective randomized trials are needed to establish if any difference in wound recurrence rates after laparoscopic or open resection of colorectal cancer exists.

Colectomy↗
PubMed1996

Basal and meal-stimulated colonic absorption.

PURPOSE: Few quantitative experiments evaluating colonic absorption of water and electrolytes have been performed using an awake, conscious animal model. The purpose of these experiments was to develop this type of model and evaluate both basal and meal-stimulated colonic absorption of water and electrolytes. METHODS: Canine Thiry-Vella fistulas were created using a 20 cm segment of distal colon under general anesthesia. Colonic absorption studies were performed using infusion of the Thirty-Vella fistulas with a buffer solution containing [14C]polyethylene glycol. Electrolyte analysis and concentration of radioactivity in the effluent were obtained and used to calculate the net flux of water, sodium, and chloride. Each study consisted of an one-hour basal period and a three-hour experimental period divided into two groups. Group 1 received no meal. Group 2 orally ingested a mixed meal at the completion of the basal hour. RESULTS: In the basal state, water and electrolytes are absorbed from the distal colon at a steady and constant rate. An orally ingested meal produces a statistically significant increase in the rate of absorption, independent of direct colonic luminal contact with the nutrients of the meal given. CONCLUSIONS: These studies demonstrate an in vivo quantitative and qualitative measure of mammalian colonic water and electrolyte absorption. An increase in absorption rate occurs in response to a meal that is probably the result of an unidentified neural or humoral signal.

Animals↗
PubMed1996

Laparoscopic evaluation of penetrating thoracoabdominal traumatic injuries.

BACKGROUND: General surgeons' recent familiarity with advanced laparoscopic techniques have rendered laparoscopy feasible safely in the trauma setting. Traditionally high rates of nontherapeutic laparotomies also contribute to this increased interest. This study was undertaken to determine the predictive value and accuracy of diagnostic laparoscopy (DL) in evaluation of penetrating thoracoabdominal trauma. METHODS: Entry criteria included thoracoabdominal gunshot (GSW) or stab wounds (SW) in otherwise hemodynamically stable patients. A high index of suspicion for either hemoperitoneum, peritonitis, or diaphragmatic injury was required for inclusion. All patients underwent DL in the operating room followed by standard laparotomy. The findings of the two evaluations were compared. RESULTS: Twenty-four patients were included in the study. Twenty males and 4 females with an average age of 34 years made up the group. Violation of the peritoneal cavity was present in 21 cases and absent in 3. No intraabdominal injuries were found during laparotomy in the latter three cases without peritoneal violation. The specificity and positive predictive value were 100% for lesions of the diaphragm, liver, spleen, pancreas, kidney, and hollow viscus. The sensitivity was highest for liver and spleen injuries (88%), followed by diaphragmatic injuries (83%), pancreas and kidney injuries (50%), and lowest for injuries of hollow viscus (25%). The negative predictive value was 95, 99, 91, and 57%, respectively, for these organs. CONCLUSIONS: DL could have avoided unnecessary laparotomy in 38% of cases in this study. There were no complications related to laparoscopy. The greatest value of DL in penetrating thoracoabdominal injuries is in the evaluation of peritoneal violation, diaphragmatic, and upper abdominal solid-organ injuries. It is not ideal for predicting hollow viscus injuries.

Abdominal Injuries↗
PubMed1996

Safe application of diagnostic laparoscopy during biventricular assistance.

We performed diagnostic laparoscopy in a patient who was critically unstable while on an ABIOMED BVS 5000 biventricular assist system. A relatively unique feature of the ABIOMED is the venous return being dependent only on gravity and the drawing force of venous return being the height of the inflow cannula compared with the level of the ABIOMED blood pump assembly; this did not preclude the use of pneumoperitoneum necessary for laparoscopy. The safe application of diagnostic laparoscopy in patients on a ventricular assist device is of importance in an era of increasing use of these devices and the increased potential for intraabdominal complications in this population.

Abdomen, Acute↗
PubMed1996

Unresolved issues in laparoscopic splenectomy.

BACKGROUND: Laparoscopy is now expanding to surgery of intra-abdominal solid organs such as splenectomy for hematologic diseases. The purpose of this study is to further demonstrate that laparoscopic splenectomy is feasible for the surgeon, teachable for the resident, and beneficial to the patient and to revise prior contraindications to this minimally invasive approach. METHODS: Thirty-three consecutive cases of laparoscopic splenectomy were performed between May 1992 and March 1996. The series included 21 females and 12 males with a median age of 42 years (range 19-79) and a median weight of 73 kg (range 36-115). Indications included: immune thrombocytopenic purpura (20), hemolytic anemia (5), hereditary spherocytosis (4), infarction with abscess (1), Hodgkin's lymphoma (1), Gaucher's disease (1), and AIDS-related thrombocytopenia (1). Dissection was predominately performed with a new surgical instrument, the harmonic shears, and main vessels were controlled with clips. RESULTS: Thirty-two (97%) of the cases were completed laparoscopically, with 1 (3%) conversion to control hilar bleeding. Four patients underwent simultaneous cholecystectomy. The median spleen size was 13 cm (range 8-28) and median weight was 256 g (range 40-2100). Median operating time was 242 minutes (range 85-515). Morbidity occurred in 2 (6%) patients: ileus and small bowel obstruction. Median hospital stay was 4 days (range 2-14). There was no mortality in our series. Median follow-up was 20 months (range 1-46) with no evidence of late surgical complication or recurrent disease. CONCLUSION: Laparoscopic splenectomy may be successful in cases previously considered contraindicated, particularly splenomegaly and splenic infarct with abscess. It is a procedure that can be learned under appropriate guidance in academic centers.

Adult↗
PubMed1996

A prospective randomized comparison of the metabolic and stress hormonal responses of laparoscopic and open cholecystectomy.

BACKGROUND: In a relatively short period of time, therapeutic laparoscopy has become an everyday part of the general surgeon's life. Although laparoscopy provides distinct clinical advantages, it is not yet clear that it lessens the stress response typical of elective surgical procedures, and as such, the morbidity of surgery. The hypothesis that laparoscopic cholecystectomy produces less of a metabolic and stress hormonal response than open cholecystectomy was tested in a prospective randomized trial. STUDY DESIGN: Twenty otherwise healthy women between 18 and 45 years of age with a history of uncomplicated symptomatic cholelithiasis undergoing either laparoscopic (n = 10) or open cholecystectomy (n = 10) were studied. The hormonal response of the adrenocortical (serum adrenocorticotropic hormone, cortisol, and urinary free cortisol), adrenomedullary (plasma and urinary epinephrine and norepinephrine), thyroid (thyroid-stimulating hormone, thyroxine, and triiodothyronine), pituitary (antidiuretic hormone and growth hormone), and glucose (serum glucose, glucagon, and insulin) homeostatic axes were measured serially over a 24-hour period. RESULTS: No difference was seen between the laparoscopic and open groups in operative time (mean plus or minus standard error of the mean, 70 +/- 6 minutes compared with 77 +/- 6.3 minutes) or hospital stay 1.3 +/- 0.2 compared with 1.1 +/- 0.1 days). Assessment of postoperative pain using an analog pain score was less in the laparoscopic group (4.9 +/- 1.3 compared with 12.3 +/- 2.5, p = 0.01). The response of the adrenocortical, adrenomedullary, thyroid, and glucose axes were similar or identical in both groups. Antidiuretic hormone levels were greater in the laparoscopic group at one hour intraoperatively (281 +/- 79 pg/mL compared with 54 +/- 18 pg/mL, p < 0.01), and at extubation (122 +/- 18 pg/mL compared with 36 +/- 7 pg/mL, p < 0.01). Serum glucose levels were greater immediately following laparoscopic cholecystectomy. Glucose and insulin levels were greater at four, 12, and 24 hours after open cholecystectomy. CONCLUSIONS: Elective laparoscopic and open cholecystectomy for uncomplicated cholelithiasis result in similar degrees of perioperative hormonal stimulation. The different hormonal responses in the immediate and later postoperative periods after laparoscopic and open cholecystectomy suggest differential stressful stimuli between the two procedures.

Adolescent↗
PubMed1995

Laparoscopic Bowel Surgery Registry. Preliminary results.

UNLABELLED: Laparoscopic surgery has evolved rapidly since 1989. The American Society of Colon and Rectal Surgeons, the Society of American Gastrointestinal Endoscopic Surgeons, and the American College of Surgeons Commission on Cancer jointly sponsored a registry to identify as early as possible the patterns of practice and acute complications of laparoscopic colectomy. METHODS: Cases were voluntarily registered by community and academic surgeons. Information was entered in the EPI-5 database. RESULTS: One thousand fifty-six cases were contributed by 118 surgeons; 763 patients were completed laparoscopically. The most common indication for surgery was cancer in 453 patients. The right colon (n = 364) and sigmoid (n = 294) were most frequently resected. Respondents felt adequate cancer resections were performed. Although several unique complications were noted, intraoperative complications were similar in type and frequency to open cases. CONCLUSION: Laparoscopic colorectal surgery can be performed with acceptable complications. It remains unclear if this approach is adequate for long-term management of colon and rectal cancer.

Colectomy↗
PubMed1995

Does peritoneal mobilization increase laparoscopic acidosis?

PURPOSE: It was hypothesized that laparoscopic colon surgery may be associated with increased absorption of CO2 resulting from mobilization of lateral peritoneal reflections. METHODS: Six pigs underwent laparotomy with removal of a measured quadrant of peritoneum before insufflation to 15 mmHg with CO2. Six paired control animals also underwent insufflation with CO2 to 15 mmHg. Measurements of the end-tidal CO2 (PetCO2), arterial blood gas analysis for CO2 (PaCO2), and pH were performed before insufflation, at 5 and 10 minutes following insufflation, then at successive 15-minute intervals for a total of two hours, and 15 minutes following desufflation. No attempt was made to correct the hypercarbia by increasing minute ventilation. RESULTS: PaCO2 reached its maximum level at two hours with values of 70.77 +/- 5.54 mmHg and 64.62 +/- 5.18 mmHg in the peritonectomized and control groups, respectively. PetCO2 also peaked at two hours to 60 +/- 13 mmHg for the study group and 54 +/- 11 mmHg for controls. pH reached its nadir at two hours, falling from a baseline of 7.45 +/- 0.08 to 7.23 +/- 0.09 in the study group, and from 7.42 +/- 0.04 to 7.24 +/- 0.04 in the control group. There were no statistically significant differences between the two groups for any of the parameters measured at each time interval. CONCLUSIONS: The hypothesis that peritonectomy produces greater CO2 absorption during CO2 pneumoperitoneum was disproved under these experimental conditions.

Absorption↗
PubMed1995

Laparoscopic-assisted colectomy learning curve.

PURPOSE: The purpose of this paper is to establish the number of cases necessary to master laparoscopic removal of the left or right colon. METHODS: Data were obtained by chart review and by individually completed questionnaires. RESULTS: A total of 144 laparoscopic-assisted or intracorporeal right or left hemicolectomies were completed by four surgeons at separate institutions. Questionnaires were completed by each surgeon for each sequential hemicolectomy, and data concerning the type of surgery and total operating time were recorded. Times were plotted to diagram individual learning curves for each surgeon, and data grouping methods were used to determine the curve for each surgeon as well as for the combined data base. Learning was said to have been completed when the surgeon's operative time reached a low point and subsequently did not vary by more than 30 minutes. A total of 78 right colectomies and 66 left colectomies were completed by the group. Respectively, each surgeon appeared to learn the procedure after 16, 21, 11, and 6 cases. When the entire database was analyzed as a whole, it was shown that between 11 and 15 completed colectomies were needed for learning, after which operative times remained relatively stable. CONCLUSIONS: This analysis, using total operative time as an indication of learning, shows that approximately 11 to 15 completed laparoscopic colectomies are needed to comfortably learn this procedure.

Colectomy↗
PubMed1995

Role of laparoscopy in colorectal surgery. A prospective evaluation of 200 cases.

PURPOSE: The aim of this study was to prospectively evaluate the role of laparoscopic-assisted surgery in patients presenting for routine colorectal surgical procedures. METHODS: Two hundred consecutive patients were assessed for the possible use of laparoscopic surgery. The decision regarding suitability of the patient for the procedure was made by the operator. For the purpose of analysis, patients were assigned to open, converted, and laparoscopic groups. RESULTS: Ninety-five of 200 patients were considered appropriate for laparoscopic surgery, 62 (65.3 percent) being successfully completed. These completed operations included right colectomy (24/30), sigmoid colectomy (22/36), appendectomy (9/10), anterior resection (3/8), abdominoperineal resection (3/5), and left colectomy (1/2). Complications attributable to laparoscopy were infrequent (6.3 percent) and were not responsible for any deaths. Patients in the laparoscopic group required less analgesia, tolerated oral intake earlier, and were discharged from the hospital earlier than those who were converted or who had open procedures. CONCLUSIONS: Laparoscopic-assisted surgery is safe, effective, and applicable to many of the standard colorectal procedures. Observed benefits include less postoperative pain and shorter hospital stay.

Adolescent↗
PubMed1995

A prospective, randomized comparison of laparoscopic appendectomy with open appendectomy. Laparoscopic Appendectomy Study Group.

BACKGROUND: While the advantages of laparoscopic cholecystectomy are clear, the benefits of laparoscopic appendectomy (LA) are more subtle. We conducted a randomized clinical trial to evaluate whether LA is deserving of more widespread clinical application than it has yet received. MATERIALS AND METHODS: Two hundred fifty-three patients with a preoperative diagnosis of acute appendicitis were randomized into three groups. LA with an endoscopic linear stapler (LAS) (U.S. Surgical Corp., Norwalk, Connecticut) was performed on 78 patients, LA with catgut ligatures (LAL) on 89, and open appendectomy (OA) on 86. LA was performed with a three-trocar technique. OA was accomplished through a right lower-quadrant transverse incision. Data with normal distributions were analyzed by analysis of variance. Nonparametric data were analyzed with either the Kruskal-Wallis H test or Fisher's exact test. RESULTS: The mean operative times for the procedures were 66 +/- 24 minutes (LAS), 68 +/- 25 minutes (LAL), and 58 +/- 27 minutes (OA). The relative brevity of OA compared to LAS and LAL was statistically significant (P < 0.01). Conversion to open procedures was approximately as frequent in the LAS group (n = 5) and the LAL (n = 6). One OA, 2 LAS, and 11 LAL patients experienced vomiting postoperatively (P < 0.05). Two intra-abdominal abscesses occurred in LAS, 4 in LAL, and 0 in OA patients (P = NS). Wound infections were more common following OA (n = 11) than LAL (n = 4) or LAS (n = 0) (P < 0.05, < 0.001). The mean length of postoperative hospital stay was 2.16 +/- 3.2 days (LAS), 2.98 +/- 2.7 days (LAL), and 2.83 +/- 1.6 (OA) (P < 0.05 OA versus LAS). The number of days patients required pain medications overall was not different between groups, but a subgroup analysis of 134 patients who rated their postoperative pain on a visual analogue scale revealed a significantly lower mean level among patients undergoing LA (LAS and LAL) versus OA (P < 0.001). Patients undergoing LA resumed regular activities sooner than those undergoing OA (9 +/- 9 days versus 14 +/- 11 days, P < 0.001). Rates of readmission to the hospital were similar for all procedures. CONCLUSIONS: Laparoscopic appendectomy appears to have distinct advantages over open appendectomy. The laparoscopic procedures produced less pain and allowed more rapid return to full activities, and LAS required shorter hospital stays. The only disadvantages to the laparoscopic approach were slightly increased operative time for both procedures, and increased emesis following LAL.

Adult↗