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Biomedical subjects

M R Cox

Publications and source records attributed to M R Cox.

At least 19 recordsLinked to original sources
PubMed2000

The effect of fundoplication on the motility of the canine lower oesophageal sphincter.

BACKGROUND: A canine model was used to define whether Nissen fundoplication inhibits gastro-oesophageal reflux by inhibiting transient lower oesophageal sphincter relaxations (TLOSR) or by creating a pressure barrier at the gastro-oesophageal junction. METHODS: Four surgical models were studied pre-operatively and postoperatively. These were: (i) the surgical mobilization required for fundoplication (sham fundoplication, n = 5); (ii) a standard fundoplication (n = 4); (iii) anterior and posterior myotomy of the lower oesophageal sphincter (LOS; cardiomyotomy, n = 4); and (iv) combined cardiomyotomy and fundoplication (n = 4). Each operative procedure was assessed for its effect on the incidence of TLOSR and gas reflux events, the mean LOS pressure and the LOS pressure profile during swallow events. RESULTS: Sham fundoplication reduced the rate of evoked TLOSR in response to gaseous gastric insufflation from 9.8+/-1.6/h (mean +/- SEM) to 5.4 +/-1.5/h. The mean LOS pressure was reduced from 25.1+/-2.6 to 18.5+/-2.1 mm Hg but nadir LOS pressure during swallowing was not altered. Nissen fundoplication virtually abolished evoked TLOSR from 10.4+/-1.2/h to 0.4+/-0.4/h, increased mean basal LOS pressure from 19.8+/-2.1 to 27.0+/-1.1 mm Hg and increased the nadir pressure on swallowing from 3.4+/-1.0 mm Hg to 14.4+/-1.0 mm Hg. Cardiomyotomy was associated with a near continuous leakage of gas across a chronically hypotensive LOS. Cardiomyotomy reduced the resting LOS pressure from 14.7+/-1.2 mm Hg to 2.3+/-1.0 mm Hg. Cardiomyotomy with fundoplication was associated with no loss of LOS competence. No gas venting episodes occurred either by passive leakage or by TLOSR. Cardiomyotomy with fundoplication was associated with a fall in mean LOS pressure from 14.3+/-1.5 mm Hg to 7.1+/-1.8 mm Hg but no LOS relaxation occurred during swallowing. CONCLUSION: Nissen fundoplication is highly effective in preventing reflux across a normal or chronically hypotensive LOS. Fundoplication results in a constant, measurable pressure barrier at the lower end of the oesophagus that is not due to a change in intrinsic LOS tone. Following fundoplication TLOSR are prevented by the constant low-pressure barrier.

Animals↗
PubMed2000

Selective vascular occlusion with staged hemihepatectomy for blunt liver trauma.

BACKGROUND: A 23-year-old man with extensive blunt trauma to the right lobe of the liver in whom adequate haemostasis could not be achieved by selective suturing and packing was encountered. Contributing factors to poor haemostasis included massive transfusion, hypothermia and acidosis. METHODS: Hepatic haemostasis was achieved by selective intrahepatic ligation of the right hepatic pedicle and packing. RESULTS: After resuscitation and stabilization in the intensive care unit, a right hemihepatectomy was performed 14 h later. CONCLUSIONS: The present case describes a modification of the Pringle manoeuvre, termed 'selective Pringle manoeuvre'. This technique is a useful additional strategy for the management of uncontrollable bleeding in massive hepatic trauma.

Acidosis↗
PubMed2000

Grasper trauma during laparoscopic cholecystectomy.

BACKGROUND: The present study characterized the histopathological nature of laparoscopic grasper trauma during laparoscopic cholecystectomy in a prospective, blinded trial in order to establish a model for laparoscopic grasper trauma. The null hypothesis that graspers cause no histologically distinct tissue injury was tested. METHODS: The gall bladders of 19 patients undergoing laparoscopic cholecystectomy were examined. The area of gall bladder that had been grasped by Debakey laparoscopic forceps was excised (sample), along with an area of gall bladder that had not been grasped (control). Paired specimens were examined by a pathologist (blinded) to identify which was 'sample' and which was 'control' and to assess for histological markers of crushed tissue injury. The data were analysed by chi-squared or Fisher's exact tests. RESULTS: The pathologist was able to identify the sample (gripped) specimen in 13 of the 19 cases. In the remaining six cases the pathologist was unable to determine the specimen that had been gripped due to either absence of damage (four cases), or severe inflammation precluding assessment (two cases). The ability of the pathologist to distinguish the sample from the control specimen was significant (chi-squared test, P = 0.003). Of the histological markers of crushed tissue injury, focal thinning of the gall bladder wall and epithelial loss were present in significantly more sample (gripped) specimens than control specimens (chi-squared test, P = 0.0002 and P < 0.0001, respectively). CONCLUSIONS: Laparoscopic graspers cause tissue trauma that can be assessed histologically. The current study presents a relevant, reproducible, ethically acceptable human model for assessing the interaction between laparoscopic graspers and soft tissues.

Adult↗
PubMed1999

Transhiatal versus Ivor-Lewis oesophagectomy: is there a difference?

INTRODUCTION: Curative oesophageal resection for carcinoma may be carried out by either the transhiatal or the Ivor-Lewis transthoracic technique. The aims of this study were to compare the morbidity, 30-day mortality and long-term survival of the two techniques in the treatment of oesophageal carcinoma and to provide data to calculate the sample sizes for a prospective randomized trial. METHODS: Results from 44 series published between January 1986 and December 1996 were reviewed. Thirty-three papers reported results on 2675 patients having transhiatal (THO) and 29 papers reported results on 2808 patients having Ivor-Lewis oesophagectomy (ILO). RESULTS: The two groups were comparable in terms of age, sex and stage of the disease. There was no apparent difference in postoperative morbidity between the two groups with respect to respiratory complications (24% for THO, 25% for ILO), cardiovascular complications (12.4% for THO, 10.5% for ILO), wound infection (8.8% for THO, 6.2% for ILO) and chylothorax (2.1% for THO, 3.4% for ILO). The transhiatal group appeared to have a higher incidence of anastomotic leaks (16% for THO, 10% for ILO), anastomotic strictures (28% for THO, 16% for ILO) and recurrent laryngeal nerve injuries (11.2% for THO, 4.8% for ILO). The 30-day mortality was 6.3% for transhiatal and 9.5% for Ivor-Lewis oesophagectomy. Overall long-term survival at 5 years was similar (24% for THO, 26% for ILO). CONCLUSIONS: The surgical approach to oesophagectomy was not an important determinant of morbidity and long-term survival in patients with oesophageal carcinoma. Transhiatal oesophagectomy was associated with a higher incidence of anastomotic complications and recurrent laryngeal nerve injury. Ivor-Lewis oesophagectomy had a higher mortality. In order to demonstrate a significant difference in morbidity or long-term survival between the two techniques 3100 patients would be required in each arm of a prospective randomized trial.

Aged↗
PubMed1998

Somatostatin stimulates the brush-tailed possum sphincter of Oddi in vitro and in vivo.

BACKGROUND & AIMS: Somatostatin, a neuropeptide and hormone, is found in the biliary tract of several species. The aim of this study was to map the distribution of somatostatin-like immunoreactive nerve fibers in the extrahepatic biliary tract of the Australian possum and to determine the pharmacological effects of somatostatin 1-14 on sphincter of Oddi activity in vitro and in vivo. METHODS: Tissue was harvested for immunohistochemistry and sphincter of Oddi for circular or longitudinal muscle contractility. In anesthetized possums, sphincter of Oddi motility was measured by manometry, and transsphincteric flow was measured gravimetrically. RESULTS: Somatostatin immunoreactivity was evident in gallbladder ganglia nerve cell bodies and in nerve fibers of the common bile duct and sphincter of Oddi. Somatostatin 1-14 increased circular and longitudinal muscle contraction amplitude 3-4-fold (P < 0.05), but only the longitudinal muscle contraction amplitude was tetrodotoxin sensitive. Somatostatin 1-14 stimulated spontaneous sphincter of Oddi motility in a tetrodotoxin-insensitive manner, increasing basal pressure, contraction frequency, and amplitude 2-4-fold (P < 0.05) and reducing transsphincteric flow to 25% of control (P < 0.0001). CONCLUSIONS: Somatostatin-like immunoreactivity is present in the extrahepatic biliary tree, and somatostatin 1-14 stimulates sphincter of Oddi smooth muscle and nerves. The major action is direct stimulation of sphincter of Oddi circular muscle, which reduces transsphincteric flow.

Animals↗
PubMed1998

Gastrin-releasing peptide stimulates gallbladder motility but not sphincter of Oddi motility in Australian brush-tailed possum.

The neural distribution and action of gastrin-releasing peptide in the extrahepatic biliary tree of the Australian brush-tailed possum was investigated. Immunohistochemical staining of fixed specimens demonstrated gastrin-releasing peptide-containing nerves throughout the neural plexuses of the gallbladder, sphincter of Oddi, and mucosa of the common bile duct. Gastrin-releasing peptide (5-2000 ng/kg) increased gallbladder tone to a level equivalent to that produced by cholecystokinin octapeptide (160 ng/kg). This action was tetrodotoxin-insensitive. Sphincter of Oddi motility and transsphincteric flow were not altered. Possible mediation of the gallbladder response by gastrin was examined. Gastrin (50-2500 ng/kg) stimulated gastric acid secretion, elevated gallbladder motility to 64% of that produced by gastrin-releasing peptide, and did not alter sphincter of Oddi motility. In conclusion, gastrin-releasing peptide-containing nerves are found in the neural plexus of the possum extrahepatic biliary tree. Gastrin-releasing peptide induces gallbladder contraction in part by a direct action on gallbladder smooth muscle and also via release of gastrin.

Animals↗
PubMed1998

Substance P stimulates sphincter of Oddi motility and inhibits trans-sphincteric flow in the Australian brush-tailed possum.

Substance P containing nerves are widely distributed throughout the gastrointestinal tract. The aims of this study were to determine the distribution of substance P containing nerves in the extrahepatic biliary tree of the Australian brush-tailed possum and to characterize the effect of exogenous substance P on the sphincter of Oddi (SO) motility and transphincteric flow in vivo. Immunohistochemical staining of fixed specimens (n = 8) found moderate numbers of substance P containing nerve cell bodies and fibres throughout the neural plexuses of the SO, in particular in the serosal and intraluminal nerve trunks of the SO and gallbladder. Synthetic porcine substance P (1-2000 ng kg-1), administered by close intra-arterial injection (i.a.; n = 7), produced a dose-dependent elevation in basal pressure [P < 0.01] and an associated dose-dependent reduction in trans-sphincteric flow [P < 0.0001]. Substance P had no significant dose-dependent effect on SO phasic contraction amplitude or frequency. Tetrodotoxin (9 micrograms kg-1, i.a.) did not inhibit the effect of substance P on SO motility and trans-sphincteric flow (n = 5). In conclusion, substance P containing nerves are found throughout the possum extrahepatic biliary tree. Exogenous substance P stimulates SO motility and reduces trans-sphincteric flow in vivo by acting directly on the sphincter smooth muscle.

Animals↗
PubMed1996

Laparoscopic common bile duct exploration: evolution of a new technique.

Laparoscopic exploration of the common bile duct (CBD) with a choledochoscope or a stone basket during laparoscopic cholecystectomy was attempted in 60 patients and was successful in 56. The cystic duct was used for entry to the CBD in 46 patients and in 14 a choledochotomy was performed. Of 51 patients with confirmed common duct stones, 38 had complete laparoscopic clearance (75 per cent). In 13 patients the duct was not cleared or was only partially cleared, of whom four went on to have clearance by postoperative percutaneous choledochoscopy down a cystic duct or T-tube track. Two patients with cystic duct tubes passed their remaining stones spontaneously. One patient had open exploration and six required endoscopic retrograde cholangiopancreatography. Of nine patients without stones, choledochoscopy was impossible in three patients whose cholangiogram was later considered to be normal. In five patients stones were excluded by choledochoscopy and in one patient laparoscopic choledochoscopy was undertaken to better define abnormal biliary anatomy; this helped to avoid major bile duct injury. Choledochoscopy was easier with the smaller 3.6-mm ureteroscope but stone removal was more difficult when the basket was too small for the stones, the cystic duct too small relative to stone size or the number of stones was too great. Successful stone clearance was proportional to the level of effort expended, and was limited by operating time and equipment.

Cholangiography↗
PubMed1996

An intervention on discharge polypharmacy.

OBJECTIVE: To determine if providing a way to cancel pre-admission prescriptions would reduce the number of active drug prescriptions (RXs) at discharge. DESIGN: A randomized non-blinded clinical trial. SETTING: Inpatient acute medical service of a university affiliated Veterans Administration medical center. PARTICIPANTS: Twelve medicine ward teams were randomized to control and intervention groups. Patients controlled had been discharged from these teams during 12 weeks and were receiving outpatient medications from this facility at hospital admission; control = 180, intervention = 168. INTERVENTION: At discharge, intervention teams used a computer-generated drug list to cancel or renew previous outpatient RXs or to prescribe new medications. Control teams could not cancel outpatient drugs and wrote all medications on individual prescriptions. MEASUREMENTS: The difference between admission and discharge RXs. RESULTS: There were no significant differences in patients' age, sex, race, Charlson Index (CI), or LOS between patient groups at discharge. The intervention group had fewer RXs on admission (5.4 vs 6.2, P < .05) and at discharge was not significantly different (2.9 vs 2.9, P = .87) from the control group. CONCLUSIONS: Providing a method for canceling pre-admission medications did not reduce the number of RXs at discharge. Further research is needed to evaluate the appropriateness of the large increase in RXs from admission to discharge for patients in acute hospital settings.

Analysis of Variance↗
PubMed1995

Laparoscopic surgery in women with a clinical diagnosis of acute appendicitis.

OBJECTIVES: To assess the routine use of diagnostic laparoscopy and laparoscopic appendicectomy in women with a clinical diagnosis of acute appendicitis. METHODS: Women who presented with a clinical diagnosis of acute appendicitis between 1 January 1992 and 31 August 1993 were prospectively assessed and 107 underwent diagnostic laparoscopy. RESULTS: Appendicitis was confirmed in 63 women (59%) and no diagnosis could be made in seven (6%). An alternative diagnosis, most commonly a gynaecological disorder, was made in 37 women (35%). Twenty-eight women with an alternative diagnosis (76%) did not require a laparotomy. Seventy-three patients had a laparoscopic appendicectomy, with an 8% conversion rate to an open operation. The morbidity rate for laparoscopic procedures was 3%, the median inpatient stay was two days and the median time to return to normal activities was eight days. CONCLUSIONS: Diagnostic laparoscopy should be performed in women who present with a clinical diagnosis of acute appendicitis to confirm the diagnosis, reduce the rate of unnecessary appendicectomy and avoid an unnecessary laparotomy. When acute appendicitis is confirmed, appendicectomy may be performed laparoscopically.

Activities of Daily Living↗
PubMed1995

Peroperative endoscopic sphincterotomy during laparoscopic cholecystectomy for choledocholithiasis.

The development of laparoscopic cholecystectomy has created a dilemma in the management of choledocholithiasis. A number of options exist, including endoscopic sphincterotomy (ES) before laparoscopic cholecystectomy in patients with suspected common bile duct (CBD) calculi, laparoscopic bile duct exploration, open CBD exploration and postoperative ES. None of these options has emerged as ideal or universally acceptable. An alternative technique, peroperative ES, has been developed. A prospective assessment of the use of peroperative ES in 13 patients in whom choledocholithiasis was demonstrated with operative cholangiography is presented. Eleven patients had successful ES and clearance of stones. The CBD could not be cannulated in one patient, and an adequate ES for stone extraction could not be performed in the remaining patient. Both procedures were converted to open CBD exploration. Complications were mild postoperative pancreatitis (two patients) and pulmonary atelectasis (one). The median total operating time was 165 min and the median postoperative hospital stay was 3 days. Peroperative ES at the time of laparoscopic cholecystectomy provides a safe technique for clearance of the CBD.

Adult↗
PubMed1995

Analysis of local recurrence rates after surgery alone for rectal cancer.

Local recurrence (LR) continues to be a major problem following surgical treatment for rectal cancer, and proposed ways of reducing this remain controversial. The aim of this study was to review results from published surgical series in which adjuvant therapies were not used. A Medline search identified series published between January 1982 and December 1992 with follow-up on at least 50 patients with rectal cancer treated surgically for cure, without adjuvant therapy. Fifty one papers reported follow-up on 10,465 patients with a median LR rate of 18.5%. LR was 8.5%, 16.3% and 28.6% in Dukes' A, B and C patients respectively, 16.2% following anterior resection and 19.3% following abdominoperineal resection. Nine papers (1,176 patients) reported LR rates of 10% or less. LR was 7.1% in 1,033 patients having total mesorectal excision and 12.4% in 476 patients having extended pelvic lymphadenectomy. Routine cytocidal stump washout in 1,364 patients was associated with 12.2% LR, however a higher proportion (41%) also underwent total mesorectal excision. In 52% of cases, LR was reported to have occurred with no evidence of disseminated disease. Surgical technique is an important determinant of LR risk. LR rates of 10% or less can be achieved with surgery alone in expert hands.

Humans↗
PubMed1995

Minimal access surgery of the gastrointestinal tract.

In the last 5 years, surgery of the gastrointestinal tract has been revolutionized by the application of minimal access techniques. Following initial enthusiasm, which suggested that most abdominal surgery would ultimately be done via this approach, there is now need for appraisal and evaluation of the role of a number of these minimal access techniques when compared with open surgery. Undoubtedly, the most convincing and total application of minimal access techniques has been in the treatment of gallstone disease. Laparoscopic cholecystectomy is now standard therapy for cholelithiasis and endoscopic sphincterotomy with stone extraction is standard therapy for choledocholithiasis. Where the two conditions co-exist, operative cholangiography allows for the recognition of stones in the bile duct at the time of laparoscopic cholecystectomy and provides the potential avenue for treatment. Most major centres also would recommend routine operative cholangiography during laparoscopic cholecystectomy for the detection of unsuspected stones and as an extra safety procedure in the early identification of potential bile duct injuries. The efficacy of laparoscopic appendicectomy and laparoscopic or thoracoscopic treatment of achalasia of the oesophagus also is supported by data from well conducted prospective studies. Doubt remains regarding the advantage of laparoscopic surgery over other approaches in the treatment of gastro-oesophageal reflux, inguinal hernias and jaundice due to non-resectable cancer. For all three of these conditions, prospective trials are underway and the results of these trials should be assessed prior to widespread adoption of the laparoscopic techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholecystectomy, Laparoscopic↗
PubMed1994

Sterilization of dental instruments and devices: an update.

Dental sterilization techniques have become a focus of attention as a result of disclosure of occupational HIV transmission from an infected dentist to a cluster of patients. Although there has never been a confirmed report of a patient acquiring an infectious blood-borne disease from a dental instrument or device, recommendations for universal sterilization of dental handpieces and other devices have recently been implemented. Because of the higher rate of hepatitis B virus transmissability in the dental health care environment, an upgrade in sterilization protocols may be warranted. Stringent sterilization standards are especially necessary in higher-risk institutional dental care settings. However, a high rate of dental sterilization errors has been reported and traced to operator error. Recent institutional dental sterilization policy changes have been developed to reduce the chance of sterilization error, further diminishing the risk of cross contamination.

Dental Equipment↗
PubMed1994

Endoscopic retrograde cholangiopancreatography following laparoscopic cholecystectomy.

Laparoscopic cholecystectomy is the preferred method of treatment for symptomatic choledocholithiasis. Since its introduction there has been an increase in postoperative diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP). The aim of this study was to assess the indications and results of ERCP following laparoscopic cholecystectomy. Sixty-one patients had an ERCP following laparoscopic cholecystectomy. Two broad groups were identified: Group 1 (35 patients) had filling defects (consistent with stones) noted on operative cholangiography, which were not successfully flushed or extracted at the time of laparoscopic cholecystectomy; Group 2 consisted of patients who developed problems following laparoscopic cholecystectomy. Nine patients had post-laparoscopic cholecystectomy pain with abnormal liver function tests (LFT), four of whom had common bile duct (CBD) injuries and three had CBD stones. Eleven patients had post-laparoscopic cholecystectomy pain with a normal diameter common bile duct on ultrasound and normal LFT; only one had a CBD stone. Five patients with a persisting bile leak following laparoscopic cholecystectomy had an ERCP and endoscopic sphincterotomy. In three the leak ceased, while two required subsequent open surgery to drain bile collections and ligate the cystic duct. One patient presented with an episode of transient jaundice but had a normal ERCP. There were six post-ERCP complications; three patients had mild pancreatitis, two had a minor haemorrhage and one an asymptomatic duodenal perforation. Endoscopic retrograde cholangiopancreatography post-laparoscopic cholecystectomy was most valuable for the management of retained stones and the diagnosis and management of post-laparoscopic cholecystectomy pain in association with abnormal LFT. The diagnostic yield was low (9%) when the LFT were normal.

Adolescent↗