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P W de Graaf

Publications and source records attributed to P W de Graaf.

At least 19 recordsLinked to original sources
PubMed2005

[Abscess formation due to lost stones during laparoscopic cholecystectomy].

Two women aged 79 and 69 years presented with abdominal pain at 15 and 38 months respectively after a laparoscopic cholecystectomy. In both cases perforation of the gallbladder had occurred with spillage of bile and gallstones. A CT-scan carried out at presentation showed signs of an abdominal abscess. The origin of the abscess was initially unknown. The first patient was operated on immediately. In the second patient a drain was placed in the abscess under ultrasound guidance. During operation gallstones were seen in the abscess cavity in both patients. Both patients recovered well. Although perforation of the gallbladder with spillage of gallstones during laparoscopic cholecystectomy often occurs, the incidence of major postoperative complications is low. However, in some cases reoperation is necessary. Removal of all spilled stones is therefore indicated to prevent complications. If abdominal symptoms persist after laparoscopic cholecystectomy, an abscess due to spilled gallstones should be considered. Ultra-sound or CT are the most sensitive means of for tracing spilled gallstones or abscesses.

Abdominal Abscess↗
PubMed2004

[Very slight chance of other metastases in axillary nodes of breast cancer patients with a small sentinel node metastasis without extranodal tumor growth].

OBJECTIVE: To determine in patients with mammary carcinoma and a sentinel node metastasis whether pathological parameters of the sentinel node metastasis and the primary tumour might have predictive value with respect to the presence of metastases in other axillary nodes. DESIGN: Prospective. METHOD: The study group consisted of the first 100 consecutive patients with a sentinel node metastasis, who subsequently underwent a complete axillary dissection. The patients with metastases in the non-sentinel nodes were compared to those without such metastases regarding the size of the largest sentinel node metastasis and the presence of extranodal tissue invasion near any such node, and size, and type of the primary tumour. RESULTS: The median size of the metastases in the sentinel lymph node in the two groups was 3 mm versus 13 mm respectively (p < 0.001) and the frequency of extranodal tissue invasion 3% versus 74% respectively (p < 0.001); the combination of these factors strongly predicted the presence of non-sentinel lymph node metastases in the axilla (94% area under the receiver operating characteristics curve). None of the 30 patients with a micrometastasis < or = 2.0 mm in the sentinel lymph node had metastases in the non-sentinel axillary lymph nodes. Metastases were present in the non-sentinel axillary lymph nodes in 29 of the 31 patients with extranodal tissue invasion near the sentinel node. CONCLUSION: In breast cancer patients with a sentinel lymph node metastasis < or = 2.0 mm and without extranodal tumour growth a complete axillary lymph node dissection might be unnecessary as the risk of additional metastases was very small.

Adult↗
PubMed2004

[Important prognostic significance of a sentinel-node biopsy in patients with malignant melanoma].

OBJECTIVE: To determine the prognostic significance of sentinel-node biopsy in patients with malignant melanoma (unlike the United States, a sentinel-node biopsy is still not routinely performed on melanoma patients in the Netherlands, as the outcomes of prospectively randomised clinical trials are being awaited). DESIGN: Retrospective. METHODS: Between 1996 and 2001 a sentinel-node biopsy and a re-excision of the scar of the diagnostic biopsy were performed on all melanoma patients who had a Breslow thickness > or = 1 mm or a Clark level > or = IV. At operation the sentinel node was identified with a gamma probe and patent blue. It was removed and sent for pathological investigation for the presence of melanoma cells. If the sentinel node was tumour positive, a dissection of the regional lymph-node basin was performed. Subsequently, these patients were put forward for the European Organisation for Research and Treatment of Cancer (EORTC) peginterferon alfa(2b) adjuvant treatment study. RESULTS: A sentinel-node biopsy was performed in 61 lymphnode basins in 57 patients (18 male and 39 female; median age: 45 years (range: 9-80)). The median Breslow thickness of the melanomas was 2.2 mm (range: 0.7-13 mm). In 10 of the 61 cases histological examination of the sentinel node demonstrated tumour cells. In 2 additional cases tumour cells were demonstrated only by immunohistochemical studies or complete dissection of the node. Eight regional lymph-node basins were dissected, two of which contained additional metastases. The median follow-up was 36 months (range: 1-68). During follow-up 12 of the 57 patients were found to have metastases, in 8 of these patients the sentinel-node biopsy contained tumour cells. The negative predictive value of a tumourless sentinel node with respect to the later occurrence of distant metastases was 92%. CONCLUSION: The patients with a tumour-positive sentinel node had a poorer prognosis with respect to distant metastases than patients with a tumour-negative node. This is the main reason for performing sentinel-node biopsy: to predict the prognosis of the disease. Therefore sentinel-node biopsy should be incorporated into the treatment of patients with malignant melanoma.

Adolescent↗
PubMed2004

Extended lymph node dissection for gastric cancer: who may benefit? Final results of the randomized Dutch gastric cancer group trial.

PURPOSE: The extent of lymph node dissection appropriate for gastric cancer is still under debate. We have conducted a randomized trial to compare the results of a limited (D1) and extended (D2) lymph node dissection in terms of morbidity, mortality, long-term survival and cumulative risk of relapse. We have reviewed the results of our trial after follow-up of more than 10 years. PATIENTS AND METHODS: Between August 1989 and June 1993, 1,078 patients with gastric adenocarcinoma were randomly assigned to undergo a D1 or D2 lymph node dissection. Data were collected prospectively, and patients were followed for more than 10 years. RESULTS: A total of 711 patients (380 in the D1 group and 331 in the D2 group) were treated with curative intent. Morbidity (25% v 43%; P <.001) and mortality (4% v 10%; P =.004) were significantly higher in the D2 dissection group. After 11 years there is no overall difference in survival (30% v 35%; P =.53). Of all subgroups analyzed, only patients with N2 disease may benefit of a D2 dissection. The relative risk ratio for morbidity and mortality is significantly higher than one for D2 dissections, splenectomy, pancreatectomy, and age older than 70 years. CONCLUSION: Overall, extended lymph node dissection as defined in this study generated no long-term survival benefit. The associated higher postoperative mortality offsets its long-term effect in survival. For patients with N2 disease an extended lymph node dissection may offer cure, but it remains difficult to identify patients who have N2 disease. Morbidity and mortality are greatly influenced by the extent of lymph node dissection, pancreatectomy, splenectomy and age. Extended lymph node dissections may be of benefit if morbidity and mortality can be avoided.

Adenocarcinoma↗
PubMed2001

[Less operations required due to perioperative frozen section examination of sentinel nodes in 275 breast cancer patients].

OBJECTIVE: To determine the reliability of a peroperative frozen section examinations of sentinel lymph nodes in mammary carcinoma. DESIGN: Retrospective. METHOD: In the Reinier de Graaf Hospital and Diagnostic Centre SSDZ Delft, the Netherlands, the results of frozen section from sentinel lymph node investigations of mammary carcinomas from 1997-2000 were compared with the final pathological results. If axillary dissection had been performed on these patients, the histopathological findings of the dissected lymph nodes were also studied. RESULTS: Frozen sections were made of 287 sentinel lymph nodes from 275 patients. A tumour was found in the sentinel lymph nodes of 64 patients and these patients immediately underwent a complete axillary lymph node dissection. For 31 of these patients a tumour was also found in the other lymph nodes. In 29 of these 31 patients, histological examination had shown extranodal extension. The frozen sections from the sentinel nodes of the remaining 211 patients were considered negative. However, in 13 of these patients, the paraffin sections of the sentinel node nevertheless showed a tumour and the remaining axillary lymph nodes were removed in a second operation. In the last 89 patients studied, the sentinel lymph nodes were cut at four levels and stained immunohistochemically at one level for cytokeratins. Accordingly micrometastases were found in the sentinel lymph nodes of 4 of the 13 patients with (false-)negative frozen sections. False-positive results did not occur. CONCLUSION: The major advantage of the sentinel node method in breast cancer is that for women without metastasis present in the sentinel node, axillary dissection is avoided. By means of a peroperative examination of frozen sections, 83% of the patients with a metastasis in the sentinel lymph node (or about one quarter of all patients) were spared from having a second operation for axillary dissection at a later stage.

Aged↗
PubMed2001

Determining laser dosimetry for consistent retinal photocoagulation.

Laser photocoagulation is used extensively by ophthalmologists to treat retinal disorders such as diabetic retinopathy, macular degeneration, and retinal tears. Currently, the procedure is performed manually and suffers from several drawbacks that a computer-assisted system could help alleviate. These drawbacks include the tedious nature of the procedure for both the patient and the physician and also the extreme criticality of the task. A system is under development that will rapidly and safely place multiple therapeutic lesions at desired locations on the retina in a matter of seconds. This system provides real-time, motion-stabilized lesion placement for typical clinical irradiation times on the order of 100 ms. Considerable work has been accomplished on stabilizing the irradiating laser on the retinal surface. Various tracking systems have been designed, prototypes implemented, and tested in vivo on laboratory animals [1]. Our efforts have most recently concentrated on developing a system to monitor lesion growth in real time and turn off the laser when the desired lesion parameters have been achieved. This subsystem employs dynamic lesion reflectance as an indirect measure of lesion depth. Our goal has been to establish a correlation between the measurable lesion reflectance parameter with the actual lesion depth. Once this correlation is established, these parameters will be used to generate a control signal for the irradiation time of the laser. The goal is to optimize the therapeutic effect, without over- or under-exposing the tissue. The result is consistent lesion formation over any part of the non-homogeneous retinal tissue.

Animals↗
PubMed2000

Improved healing of extraperitoneal intestinal anastomoses in the early phase when surrounded by omentum.

BACKGROUND: The extra-anatomical position of a cervical oesophagogastrostomy is a reason for impaired anastomotic healing, but transposition of the omentum that is covered with mesothelial cells may be a way to improve that. METHOD: This hypothesis was tested in a rat model. An end-to-end jejuno-jejunostomy was placed subcutaneously in group I (n = 29), subcutaneously surrounded by omentum in group II (n = 29) and intra-abdominally surrounded by omentum in group III (n = 20). After 3, 7 or 14 days, the rats were sacrificed and bursting pressure (BP) of the anastomosis or jejunum was measured and the hydroxyproline (HP) level was determined. RESULTS: In group I 5/29, in group II 2/29 and in group III 0/20 rats died following anastomotic leakage (nonsignificant) and were excluded from other measurements. BP was decreased after 3 days in group I (60+/-9 mm Hg) compared with group II (101+/-8 mm Hg) and group III (107+/-11 mm Hg) (p = 0.002). After 7 days, BP in groups I (122+/-10 mm Hg) and II (132+/-10 mm Hg) were lower as compared with group III (230+/-8 mm Hg) (p<0.001). Differences in HP levels were not statistically significant between the groups after 3, 7 and 14 days. CONCLUSION: The healing of intestinal anastomoses in an extraperitoneal position is improved in the early phase only when surrounded by omentum.

Anastomosis, Surgical↗
PubMed2000

Deriving irradiation control parameters for laser photocoagulation on the retina.

Laser photocoagulation is used extensively by ophthalmologists to treat retinal disorders such as diabetic retinopathy and retinal breaks. Currently, the procedure is performed manually and suffers from several drawbacks that a computer-assisted system could help alleviate. Such a system is under development that will rapidly and safely place multiple therapeutic lesions at desired locations on the retina in a matter of seconds. This system provides real-time, motion-stabilized lesion placement for typical clinical irradiation times (100 ms). When performing laser photocoagulation on the retina, the dynamic reflectance of the lesion formed by the laser may be used as a control signal. Using digital filtering and estimation techniques on the sampled reflectance signal, the latency time and growth rate are determined. These parameters are used to derive a control signal for the irradiation time of the laser. The goal is to optimize the therapeutic effect, without overexposing the tissue. The result is consistent lesion formation over any part of the retina.

Laser Coagulation↗
PubMed1999

Extended lymph-node dissection for gastric cancer.

BACKGROUND: Curative resection is the treatment of choice for gastric cancer, but it is unclear whether this operation should include an extended (D2) lymph-node dissection, as recommended by the Japanese medical community, or a limited (D1) dissection. We conducted a randomized trial in 80 Dutch hospitals in which we compared D1 with D2 lymph-node dissection for gastric cancer in terms of morbidity, postoperative mortality, long-term survival, and cumulative risk of relapse after surgery. METHODS: Between August 1989 and July 1993, a total of 996 patients entered the study. Of these patients, 711 (380 in the D1 group and 331 in the D2 group) underwent the randomly assigned treatment with curative intent, and 285 received palliative treatment. The procedures for quality control included instruction and supervision in the operating room and monitoring of the pathological results. RESULTS: Patients in the D2 group had a significantly higher rate of complications than did those in the D1 group (43 percent vs. 25 percent, P<0.001), more postoperative deaths (10 percent vs. 4 percent, P= 0.004), and longer hospital stays (median, 16 vs. 14 days; P<0.001). Five-year survival rates were similar in the two groups: 45 percent for the D1 group and 47 percent for the D2 group (95 percent confidence interval for the difference, -9.6 percent to +5.6 percent). The patients who had R0 resections (i.e., who had no microscopical evidence of remaining disease), excluding those who died postoperatively, had cumulative risks of relapse at five years of 43 percent with D1 dissection and 37 percent with D2 dissection (95 percent confidence interval for the difference, -2.4 percent to +14.4 percent). CONCLUSIONS: Our results in Dutch patients do not support the routine use of D2 lymph-node dissection in patients with gastric cancer.

Aged↗
PubMed1999

Impaired healing of extraperitoneal intestinal anastomoses.

BACKGROUND: The extra-anatomical position of a cervical oesophagogastrostomy might be a reason for impaired anastomotic healing. METHODS: This hypothesis was tested in a rat model. Jejunal resection with an end-to-end jejunojejunostomy was placed intra-abdominally in group 1 (n = 24) and subcutaneously in group 2 (n = 30). Jejunum without anastomosis was placed subcutaneously in group 3 (n = 12). After 3, 7 or 14 days the rats were killed; the bursting pressure of the anastomosis or jejunum was measured and the hydroxyproline level was determined. RESULTS: Two of 24 rats in group 1 and eight of 30 in group 2 died following anastomotic leakage (P not significant) and were excluded from other measurements. Bursting pressure was decreased after 3 days in group 1 (mean(s.e.) 62(10) mmHg) and group 2 (57(10) mmHg) compared with that in group 3 (204(17) mmHg) (P < 0.001). After 7 days, it was in the normal range in group 1 (200(14) mmHg), but lower in group 2 (104(15) mmHg) compared with that in group 3 (230(8) mmHg) (P < 0.001). Differences in hydroxyproline levels were not statistically significant between the groups after 3, 7 and 14 days. CONCLUSION: Healing of jejunojejunostomies is impaired in an extraperitoneal position compared with an intra-abdominal position.

Anastomosis, Surgical↗
PubMed1999

A method to control irradiation time for laser photocoagulation of the retina--Part II.

When performing laser photocoagulation of the retina, the dynamic reflectance of the lesion formed by the laser may be used as a control signal. Using digital filter and estimation techniques on the sampled reflectance signal, the latency time and growth rate of the lesion reflectance are determined. These parameters are then used to estimate the absorption coefficient of the irradiated tissue. From these estimates, the irradiation time of the laser can be accurately determined so that optimum therapeutic effect may be obtained, without overexposing the tissue. The result is consistent lesion formation over any part of the retina. This paper is a follow up to [4] and provides details of the experimental setup and signals acquisition.

Humans↗
PubMed1999

Hybrid tracking system for retinal photocoagulation prototype II.

Laser photocoagulation has been employed extensively by ophthalmologists to treat retinal diseases and disorders such as diabetic retinopathy, macular degeneration, and retinal tears. Treatment is a manual task requiring the physician to carefully place therapeutic lesions on the retina while avoiding critical vision anatomy. We have developed a hybrid tracking system using two retinal tracking modalities: a digital imaging-based subsystem and an analog tracking subsystem to stabilize the irradiating laser on the retina. We have also investigated a lesion parameter control subsystem to provide uniform therapeutic lesions.

Biomedical Engineering↗
PubMed1998

[The detection of melanoma metastases in sentinel nodes by polymerase chain reaction].

OBJECTIVE: To investigate the possibility of detecting melanoma metastases using molecular biological techniques in patients with a primary malignant melanoma. DESIGN: Descriptive. SETTING: Reinier de Graaf Gasthuis Hospital Delft and diagnostic centre SSDZ Delft, the Netherlands. METHODS: A melanoma specific tyrosinase mRNA was amplified using the reverse transcriptase polymerase chain reaction (RT-PCR) technique. RESULTS: A total of 23 sentinel nodes derived from 9 patients were examined. In 14 sentinel nodes metastases were found using RT-PCR. In microscopic slides stained with haematoxylin and eosin (HE) melanoma metastases were found in 2 sentinel nodes of 2 patients. With immunohistochemistry melanoma metastases were found in the same 2 sentinel nodes. CONCLUSION: It is possible to detect melanoma metastases in sentinel nodes using molecular biological techniques.

Adult↗
PubMed1998

The vascularization of a gastric tube as a substitute for the esophagus is affected by its diameter.

The stomach is used for reconstruction of the upper gastrointestinal tract after esophageal resection for cancer. The whole stomach can be used, but also a wide or narrow gastric tube can be constructed. Short-term functional results are superior after use of a narrow tube. Healing of the cervical esophagogastrostomy can be impaired, leading to leakage and stricture. The decreased vascularization at the site of the anastomosis may be one reason. It was hypothesized that the quality of the vascularization of the gastric tube, used as a substitute for the oesophagus after esophagectomy, depends on its diameter. The vascularization of postmortem specimens was studied using angiography. Whole stomachs (3), wide (3) and narrow gastric tubes (3) were constructed. In a patient with an anastomotic stricture of a narrow tube with a cervical esophagogastrostomy vascularisation was evaluated by angiography. After infusion of contrast through the supplying arteries, the whole stomachs and wide gastric tubes showed adequate vascularization, whereas the narrow gastric tube showed poor vascularization especially at the site of the anastomosis. In narrow gastric tubes, the right gastroepiploic artery was the only feeding artery. In the patient's angiography, a limited contrast visualization of the proximal end of the gastric tube could be demonstrated. Although a narrow gastric tube is favoured by some surgeons, the use of whole stomach or a type of gastric tube with preservation of the right gastric artery may lead to a better anastomotic healing.

Adult↗
PubMed1997

A method to control irradiation time for laser photocoagulation on the retina.

When performing laser photocoagulation on the retina, the dynamic reflectance of the lesion formed by the laser may be used as a control signal. Using digital filter and estimation techniques on the sampled reflectance signal, the latency time and growth rate of the lesion reflectance are determined. These parameters are then used to estimate the absorption coefficient of the illuminated tissue. From these estimates, the irradiation time of the laser can be accurately determined so that optimum therapeutic effect may be obtained, without overexposing the tissue. The result is consistent lesion formation over any part of the retina.

Laser Coagulation↗