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Biomedical subjects

J R Monson

Publications and source records attributed to J R Monson.

At least 91 records · Page 5Linked to original sources
PubMed1994

Abdominal wall metastases following laparoscopy.

Only 18 cases of recurrence at the sites of cannula insertion after laparoscopy have been reported in the literature, ten of them in the past year. The period between laparoscopic surgery and presentation of wound metastasis varies widely, from 7 days to 10 months; the lesions are typically hard, craggy and painful. The most likely mechanism is direct implantation of viable exfoliated tumour cells but three aspects specific to laparoscopy may also be important. First, there may be increased exfoliation of tumour cells following manipulation by laparoscopic instruments of an unsuspected malignancy. Second, there may be repeated close contact between tumour-laden instruments and the port. Third, the passage of resected tissue through a small incision may coat the wound with potentially malignant cells.

Abdominal Muscles↗
PubMed1994

Laparoscopic surgery in patients with human immunodeficiency virus.

Fifteen patients with acquired immune deficiency syndrome (AIDS), and one who tested positive for human immunodeficiency virus but had no AIDS-defining diagnosis, underwent a range of laparoscopic procedures between March 1991 and March 1993. Seven cholecystectomies and one cholecystojejunostomy were performed. Three patients underwent diagnostic laparoscopy after presenting with abdominal emergencies. Two further patients had laparoscopic adhesiolysis and one appendicectomy. A further patient underwent laparoscopically assisted end colostomy and another an inguinal hernia repair, both performed electively. Two patients died in the postoperative period. There was little postoperative morbidity. Six patients died 3-18 months after surgery from progressive AIDS. This early experience suggests that laparoscopic surgery is well tolerated in these patients.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Laparoscopic sigmoid colectomy: total laparoscopic approach.

Laparoscopic surgery seems set to make a significant impact on the practice of colorectal surgery. However, to date, the majority of surgeons have used a technique of laparoscopic assistance whereby initial laparoscopic mobilization of the bowel is followed by extracorporeal mesenteric and bowel division and subsequent restoration of bowel continuity. This report describes a technique of totally laparoscopic left-sided colonic resection, transanal specimen delivery, and intracorporeal colorectal anastomosis. The technique employed is described in detail and the indications and controversies surrounding such an approach are discussed.

Anastomosis, Surgical↗
PubMed1994

m17-1A-, c17-1A- and cSF25-mediated antibody-dependent cell-mediated cytotoxicity in patients with advanced cancer.

The anti-tumour antibody-dependent cell-mediated cytotoxicity (ADCC) capacity of the conventional antibody m17-1A was compared with its chimerised analogue c17-1A and a newer chimeric antibody, cSF25, specific for colonic adenocarcinoma. The results (AUC units +/- s.e.m., control versus cancer) show that mononuclear cells from patients with adenocarcinoma mediate ADCC as efficiently as those from controls for m17-1A (143 +/- 14 vs 153 +/- 14), c17-1A (174 +/- 16 vs 189 +/- 14) cSF25 (215 +/- 18 vs 237 +/- 13) and effectors and targets alone (57 +/- 9 vs 51 +/- 8). Both chimeric antibodies mediated ADCC more effectively than m17-1A with cSF25 consistently producing the highest lysis. Furthermore, more efficient ADCC was found to correspond with monocyte activation examined flow cytometrically. The results (mean channel fluorescence) show that HLA-DR expression is increased with c17-1A (1436 +/- 200) and cSF25 (2252 +/- 298) above that observed when effectors and targets were incubated alone (1157 +/- 168) or with m17-1A (1286 +/- 170). Similarly, interleukin 2 receptor (IL-2R) expression (percentage of positive cells) was augmented in the presence of m17-1A (15 +/- 3), c17-1A (14 +/- 3) and cSF25 (25 +/- 3) when compared with no antibody (9 +/- 2). We discuss the possibility that the superior ADCC activity of chimeric antibodies, especially cSF25, may be due to increased monocyte activation.

Adenocarcinoma↗
PubMed1994

Laparoscopic herniorrhaphy: initial experience in 126 patients.

The initial experience in laparoscopic transabdominal preperitoneal mesh (TAPP) repairs is reviewed. In this study, consecutive TAPP repairs were performed in 126 patients. There were no intraoperative complications, and only 1 procedure had to be converted to open surgery. Forty-six patients had direct inguinal hernias, 56 had indirect inguinal hernias, and 24 had both, of which 21 were recurrent. Fifty-one hernias were right sided, 46 were left sided, and 29 were bilaterals. The male/female ratio was 116:10, and the mean age of the patients was 49.8 (range 17-76). Minor complications included parasthesia over the distribution of the lateral cutaneous nerve of the thigh in 2 patients, hydrocoeles in 2 patients, hematomata in 6 patients, and testicular pain in 4 patients, all of which resolved on conservative management. Incomplete bowel obstruction has been the only major postoperative complication to date, where an area of bowel herniated between two staples in the peritoneum. This was further complicated by an aspiration pneumonia and death of the patient. The mean hospital stay was 1.2 days (range 1-3), and the mean return to unrestricted activity was 8 days (range 3-12). There have been 2 true recurrences to date. One patient had a tender swelling after the repair, which was thought to be a recurrent strangulated hernia. On investigation, it was found to be a hematoma. The mean follow-up has been 7 months (range 1-18). Although early results of the TAPP repair are encouraging, we have had 1 significant complication that may have been avoided if an endoscopic extraperitoneal approach was employed.

Adolescent↗
PubMed1994

Laparoscopic varicocelectomy.

We report our initial experience of laparoscopic ligation of varicocele in 13 patients with a mean age of 34 years (range 18-39). Eight patients were subfertile, and the rest complained of dragging pain and discomfort in the left scrotum. At laparoscopy the peritoneum overlying the spermatic vessels was divided, and the spermatic veins were mobilized, clipped, and divided. The spermatic artery was identified and preserved in 11 of the 13 cases. The patients were discharged within 24 h of hospital admission. Semen quality improved in seven of the eight subfertile patients studied with a mean follow-up of 8 months. Four patients who were operated on for pain and discomfort had symptomatic improvement by the time of their first outpatient visit at 3 months. One patient complained of paresthesia along the anterior aspect of his thigh, which resolved in 6 weeks. There were no other complications. Laparoscopic varicocelectomy is a safe and effective minimally invasive procedure for treatment of clinical varicocele.

Adolescent↗
PubMed1994

Cause and prevention of electrosurgical injuries in laparoscopy.

BACKGROUND: Electrosurgical injuries occur during laparoscopic operations and are potentially serious. The overall incidence of recognized injuries is between one and two patients per 1,000 operations. The majority go unrecognized at the time of the electrical insult and commonly present three to seven days afterward with fever and pain in the abdomen. Since these injuries appear late the pathophysiology remains speculative. STUDY DESIGN: This article reviewed the physics of electrosurgery and provides the surgeon with an insight to the mechanisms responsible in each type of injury. In addition, a comprehensive search of the world literature has reviewed all articles on the topic. RESULTS: The main causes of electrosurgical injuries are: inadvertent touching or grasping of tissue during current application, direct coupling between a portion of intestine and a metal probe that is touching the activated probe, insulation breaks in the electrodes, direct sparking to the intestine from the diathermy probe, and current passage to the intestine from recently coagulated, electrically isolated tissue. The majority of injuries, not surprisingly, are caused by monopolar diathermy. Bipolar diathermy is safer and should be used in preference to monopolar diathermy, especially in anatomically crowded areas. CONCLUSIONS: An awareness of the hazards of diathermy together with an understanding of the mechanisms of injury should enable the surgeon to dissect tissue and to achieve hemostasis, while at the same time decreasing the risk of serious complications to the patient.

Burns, Electric↗
PubMed1994

Comparison between peripherally implanted ports and externally sited catheters for long-term venous access.

In a comparative study, we examined the use of a peripherally implantable venous access system which does not require either central venous cannulation or radiological screening. We compared the complication rate in 85 patients receiving this system with that in 112 similar patients receiving Hickman lines. In addition, we examined the safety and cost implications of using a ward setting instead of full operating facilities for port insertion. There was a 10.7% incidence of early and 37.6% incidence of late complications in the group receiving Hickman lines compared with only 2.4% early complications and 10.6% late complications in those receiving peripherally implantable ports. There was no difference in complication rates between those patients who had the ports inserted in a ward side room compared with those who had their procedure performed in the operating theatre. We have demonstrated the ease and reliability of port insertion in the absence of screening radiology and we therefore suggest the peripheral port as a safe, cost-effective alternative to existing venous access systems.

Adolescent↗
PubMed1994

Thoracoscopic Heller's cardiomyotomy: a new approach for achalasia.

The authors performed Heller's myotomy using an endothoracoscopic technique on two patients with swallowing difficulties that were clinically demonstrated to be oesophageal achalasia. At 12 and 18 months' followup, respectively, both patients were asymptomatic. Extramucosal cardiomyotomy, as reported by Heller in 1913, is the most common approach to repair achalasia of the oesophagus. The advantages of the laparoscopic technique (less pain, small scars, reduced hospital stay) are given, as well as the disadvantages (possible mobilization of left lateral liver segment, possible splenic damage, difficulty retracting abdominal contents). More studies are needed to determine the rate of pulmonary complications caused by the extended degree of pulmonary collapse in the thoracoscopic approach and to compare the laparoscopic and thoracoscopic approaches to Heller's myotomy.

Adult↗
PubMed1993

Advanced techniques in abdominal surgery.

Almost every abdominal organ is now amenable to laparoscopic surgery. Laparoscopic appendicectomy is a routine procedure which also permits identification of other conditions initially confused with an inflamed appendix. However, assessment of appendiceal inflammation is more difficult. Almost all colonic procedures can be performed laparoscopically, at least partly, though resection for colonic cancer is still controversial. For simple patch repair of perforated duodenal ulcers laparoscopy is ideal, and inguinal groin hernia can be repaired satisfactorily with a patch of synthetic mesh. Many upper abdominal procedures, however, still take more time than the open operations. These techniques reduce postoperative pain and the incidence of wound infections and allow a much earlier return to normal activity compared with open surgery. They have also brought new disciplines: surgeons must learn different hand-eye coordination, meticulous haemostasis is needed to maintain picture quality, and delivery of specimens may be problematic. The widespread introduction of laparoscopic techniques has emphasised the need for adequate training (operations that were straight-forward open procedures may require considerable laparoscopic expertise) and has raised questions about trainee surgeons acquiring adequate experience of open procedures.

Abdomen↗
PubMed1993

Polymorphonuclear leukocyte activation. An early marker of the postsurgical sepsis response.

It has been suggested that major surgery induces polymorphonuclear leukocyte (PMNL) dysfunction, which exposes patients to the development of sepsis. Conversely, the sepsis response and multisystem organ failure in patients after surgery is thought to be mediated by activated PMNLs. In a preliminary attempt to investigate this paradox, we studied functional (hydrogen peroxide production) and phenotypic (the adhesion/complement receptor CD11b) markers of PMNL activation in 28 patients undergoing elective major resectional surgery; 11 (39%) of these patients developed postoperative sepsis (the septic group). The mean (SEM) preoperative level of neutrophil CD11b expression (97.8 [6.2] mean channel fluorescence [MCF] and 101.42 [7.9] MCF; P = .74) and hydrogen peroxide production (109.51 [4.91] MCF and 104.53 [6.3] MCF; P = .5) were similar for the uncomplicated and septic groups, respectively. However, on the first postoperative day, both mean CD11b expression and hydrogen peroxide production were greater in those patients who subsequently developed postoperative sepsis (192.5 [38] MCF vs 128.6 [8.1] MCF for the septic group vs the uncomplicated group, respectively [P < .05], and 120.43 [2.56] MCF vs 109.61 [3.05] MCF for the septic group vs the uncomplicated group, respectively [P < .0001]). We suggest that an exaggerated PMNL activation response to surgery is an early event in those patients destined to develop postsurgical sepsis.

Aged↗
PubMed1993

Changes in major histocompatibility complex class II expression in monocytes and T cells of patients developing infection after surgery.

Expression of class II major histocompatibility complex (MHC) on monocytes is a prerequisite for effective antigen presentation and processing, an important component of the immune response to infection. It has been reported that the level of monocyte class II expression may identify patients who go on to develop infective complications following trauma. In the present study, flow cytometry was used to measure MHC class II (human leucocyte antigen (HLA)-DR) expression on circulating monocytes and T cells in 36 patients undergoing elective major resectional surgery, of whom 12 developed septic complications. The percentage of HLA-DR positive monocytes fell significantly on the first day after operation in both groups (P < 0.001) but was significantly higher in those without than in those with sepsis on days 1, 3 and 5 (P < 0.05). In contrast, the level of T cell HLA-DR expression rose significantly on the first day after operation (P < 0.05) in patients without sepsis to a level higher than in those who developed infection (P < 0.05). These findings have important implications, as predictive biological elements and for biological response modification, in patients at risk of developing sepsis after surgery.

Adult↗
PubMed1993

Long-term circulatory access via a peripheral implantable port.

The use of a novel indwelling central venous catheter system is described which combines the safety of peripheral venous catheter placement with a novel electromagnetic locator device for guidance of the catheter tip into the correct position. This locator system obviates the need for radiological screening or chest radiography for checking catheter placement. Fifty-one patients were studied prospectively and all were successfully cannulated. An infection rate of 0.29 per 1000 catheter-days was seen with a mean system life of 220 (range 15-510) days. The new port has a lower infection rate than other commonly used systems and eliminates complications such as pneumothorax and puncture of major arteries.

Adult↗
PubMed1993

Multidrug-resistant colonic cancer cell line LoVoDx is efficiently killed by lymphokine-activated killer cells from patients with carcinoma of the colon.

Multidrug-resistant (MDR+) cancer cells have the ability to grow in the presence of cytotoxic concentrations of antineoplastic drugs as a result of possessing the transmembrane drug efflux pump p-glycoprotein. The MDR+ colonic cancer cell line LoVoDx (derived from the drug-sensitive line LoVo) was tested for sensitivity to lymphokine-activated killer (LAK) cell-mediated toxicity. LAK cells were cultured from patients with colonic cancer and from matched controls with benign disorders. LAK cells from patients with cancer were as effective as those from controls in mediating cytotoxicity. The MDR+ cell line was significantly more sensitive to LAK cell-mediated cell killing than its parental drug-sensitive line LoVo (P < 0.05). These results indicate a possible role for adoptive immunotherapy in MDR+ tumours expressing p-glycoprotein.

Antineoplastic Agents↗
PubMed1993

High-energy shock waves pyrotherapy. A new concept in extracorporeal tumour therapy.

High-intensity shock waves (HISW) waves can produce rapid and intense tissue heating. We have studied a novel device capable of simultaneous shock wave generation, focusing and extracorporeal delivery along with imaging of the proposed target. Shock waves are generated by piezo-electric crystals and target a focal point of 10 x 2 mm. In a preliminary study, three groups of land race pigs received HISW to discrete points on the liver parenchyma. There was no mortality in any group. Cardiovascular monitoring revealed that HISW did not induce any haemodynamic changes during treatment and that core temperatures and liver function tests were unaffected by this therapy. Ultrasound monitoring during treatment demonstrated discreet hyperechoic areas with acoustic shadowing suggesting cavitation. Animals killed immediately after 48 h of HISW therapy had discrete necrotic cylinders within the liver with a mean diameter of 2 cm (+0.21 SD). Histological examination revealed a pattern of necrosis and vascular changes suggestive of ischaemia. In addition, there were areas of coagulative necrosis consistent with thermal injury. Animals killed at 2 months had necrotic cavities which had become surrounded by mature fibrosis. These early results indicate that high energy shock waves delivered extracorporeally can cause specific destruction of liver tissue by focused hyperthermia and cavitation. Clinical studies of this device are required to assess the possible virtue of HISW in the treatment of liver and other tumours.

Animals↗
PubMed1993

Experience with laparoscopic colorectal surgery for malignant disease.

Laparoscopic or laparoscopic-assisted surgery for colorectal cancer was attempted in 59 patients suffering from malignant disease of the anus, rectum and colon over a 20-month period. Conversion to open surgery was necessary in 5 patients (8.4%). The peroperative (30-day) mortality was 5.8%, and in two of the three patients who died this was attributable to thrombo-embolic complications. The cancer-related mortality was 8%. There were 5 Dukes' A, 21 Dukes' B and 25 Dukes' C lesions resected, and thus far all recurrences were in patients who had Dukes' C lesions. The resection margins and lymph node yield in these specimens were similar to those achieved with conventional open surgery. Six patients also had hepatic metastases recognized at the time of primary surgery. These preliminary data indicate the feasibility of performing laparoscopic-assisted resection of colorectal cancer without compromising the accepted principles of excisional surgery for malignant disease. However, a number of important issues such as thrombo-embolic prophylaxis, specimen retrieval and the long-term recurrence rates require further study before these procedures are widely adopted for colorectal cancer.

Adult↗