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Biomedical subjects

Calvin S H Ng

Publications and source records attributed to Calvin S H Ng.

At least 19 recordsLinked to original sources
PubMed2006

Video-assisted thoracic surgery lobectomy for lung cancer is associated with less immunochemokine disturbances than thoracotomy.

OBJECTIVE: Major surgery is immunosuppressive and could have an impact on postoperative tumor immunosurveillance and recurrence in cancer patients. Low circulating levels of insulin growth factor binding protein (IGFBP)-3 have been linked to advance prostate and the development of colonic cancers. This prospective study examined the early postoperative circulating levels of IGFBP-3, matrix metalloproteinase (MMP)-9, and tissue inhibitor of metalloproteinase (TIMP)-1 in early stage non-small cell lung cancer (NSCLC) patients undergoing major lung resection by VATS versus thoracotomy. METHODS: Forty-two consecutive patients with resectable primary NSCLC were assigned to VATS or thoracotomy approach over a 7-month-period. Blood samples were collected preoperatively and postoperatively on days (POD) 1 and 3 for enzyme linked immunosorbent assay determination of IGFBP-3, MMP-9 and TIMP-1 levels in the serum. RESULTS: There were no demographic differences between the two groups. VATS lung resection was associated with lower levels of MMP-9 and TIMP-1 on POD1 (median 628 vs 1311ng/ml, p=0.009; and 131 vs 211ng/ml, p=0.004, respectively) but higher levels of IGFBP-3 on POD3 (1366 vs 1144ng/ml, p=0.02), when compared with the thoracotomy approach. There was no perioperative mortality. CONCLUSIONS: VATS major lung resection for NSCLC is associated with higher circulating levels of IGFBP-3, and lower levels of MMP-9 and TIMP-1, compared to the thoracotomy approach. The clinical relevance of these postoperative changes on tumor biology following lung resection for cancer warrants further investigation.

Aged↗
PubMed2006

Differential, time-dependent effects of perivenous application of fibrin glue on medial thickening in porcine saphenous vein grafts.

OBJECTIVE: Neointimal and medial thickening play a critical role in late vein graft failure following CABG. Previous ex vivo experiment suggested that perivenous application of fibrin glue may reduce the damage in the circular smooth muscle cell layer of the media of the vein graft shortly after exposing to arterial pressure. However, the in vivo as well as the longer term impact of this intervention remain unknown. METHODS: Bilateral saphenous vein-carotid artery interposition grafting was performed in eight large white pigs (35-45 kg). In each pig, one of the grafts was randomly selected to receive perivenous fibrin glue support while the contralateral graft served as control. At 1 and 4 months following surgery (n=4 pigs in each group), all 16 patent vein grafts were removed and pressure-fixed. Multiple histological sections from each graft were prepared. Proliferating cell nuclear antigen (PCNA) was detected by immunocytochemistry. Vein graft morphology was assessed using computer-aided planimetry. RESULTS: Although perivenous application of fibrin glue had little effects either on medial thickness 1 month after implantation or on PCNA index, it significantly increased medial thickness (control: 0.37+/-0.02 mm; treated: 0.55+/-0.02 mm, p<0.001) and total wall thickness (control: 0.75+/-0.04 mm; treated: 0.92+/-0.04 mm, p=0.008) at 4 months (mean+/-SEM; n=4 in each group). CONCLUSIONS: Our data indicated that perivenous application of fibrin glue enhances graft thickening and as such does not constitute a strategy for preventing late vein graft failure after CABG.

Anastomosis, Surgical↗
PubMed2006

Inflammatory response to pulmonary ischemia-reperfusion injury.

Lung ischemia-reperfusion (IR) injury is one of the most important complications following lung transplant and cardiopulmonary bypass. The pulmonary dysfunction following lung IR has been well documented. Recent studies have shown that ischemia and reperfusion of the lung may each play significant yet differing roles in inducing lung injury. The mechanisms of injury involving neutrophil activation, and the release of numerous inflammatory mediators and oxygen radicals also contributes to lung cellular injury, pneumocyte necrosis, and apoptosis. We herein review the current understanding of the underlying mechanism involved in lung IR injury. The biomolecular mechanisms and interactions which lead to the inflammatory response, pneumocyte necrosis, and apoptosis following lung IR therefore warrant further investigation.

Humans↗
PubMed2006

Analgesic effect of electroacupuncture in postthoracotomy pain: a prospective randomized trial.

BACKGROUND: The role of electroacupuncture in postthoracotomy pain control is uncertain. We conducted a pilot study to evaluate the role of electroacupuncture in the management of early postthoracotomy wound pain. METHODS: A total of 27 patients with operable non-small cell lung carcinoma who received thoracotomy were recruited and randomized to receive either electroacupuncture or sham acupuncture in addition to routine oral analgesics and patient-controlled intravenous analgesia for postoperative pain control. All patients received acupuncture twice daily with visual analog pain score recorded for the first 7 postoperative days. Specific chest acupoints (LI 4, GB 34, GB 36, and TE 8) were targeted. Patient-controlled analgesia was used for the first 3 postoperative days in all patients, and the cumulative dosage used was recorded. RESULTS: Two patients were excluded after randomization because of complications unrelated to acupuncture. Interventions and data collection were completed for the remaining 25 patients (13 in the electroacupuncture group; 12 in the sham acupuncture group). There was a trend for lower visual analog scale pain scores in the electro-acupuncture group between postoperative days 2 and 6, although this did not reach statistical significance. The cumulative dose of patient-controlled analgesia morphine used on postoperative day 2 was significantly lower in the electroacupuncture group (7.5 +/- 5 mg versus 15.6 +/- 12 mg; p < 0.05). Such delay of onset of pain control may be related to the frequency of electroacupuncture used. CONCLUSIONS: Electroacupuncture may reduce narcotic analgesic usage in the early postoperative period. A prospective randomized controlled trial using different electroacupuncture frequency is warranted to verify this benefit.

Acetaminophen↗
PubMed2006

Video-assisted thoracic surgery pulmonary resection for lung cancer in patients with poor lung function.

BACKGROUND: The aim of this study is to evaluate the early outcome of patients with poor lung function who underwent video-assisted thoracic surgery (VATS) pulmonary resection for primary non-small cell lung carcinoma. METHODS: We reviewed retrospectively the records of patients with lung cancer undergoing VATS lung resection over a period of 5 years. Twenty-five patients with preoperative poor lung function defined as forced expiratory volume in 1 second less than 0.8 L or the percentage predicted value for forced expiratory volume in 1 second less than 50% were identified. Thirteen patients underwent VATS lobectomies and 12 VATS wedge resections. Data were analyzed with respect to demographics, risk factors, and early postoperative outcome and survival. RESULTS: There were 8 cases of morbidities (29%) and no surgical mortality. Five of these 8 patients had respiratory-related complications after surgery. A deterioration in pulmonary performance as indicated by the Eastern Cooperative Oncology Group (ECOG) score was seen in 7 patients (28%), with only 1 patient having an ECOG score greater than 2. No patient required home oxygen supplementation beyond the third month postoperatively. After a median follow-up period of 15.1 months (range, 1 to 24), 5 patients died. Only 1 patient (4%) died of a respiratory complication (pneumonia 6 weeks after surgery). The other 4 deaths were due to recurrent or metastatic disease. The actuarial survival rates at 1 and 2 years were 80% and 69%, respectively. CONCLUSIONS: Video-assisted thoracic surgery pulmonary resection for cancer in patients with poor lung function can achieve acceptable functional and oncologic outcome.

Aged↗
PubMed2006

Prophylactic ilioinguinal neurectomy in open inguinal hernia repair: a double-blind randomized controlled trial.

OBJECTIVE: We conducted a double-blinded randomized controlled trial to investigate the short- to mid-term neurosensory effect of prophylactic ilioinguinal neurectomy during Lichtenstein repair of inguinal hernia. METHOD: One hundred male patients between the age of 18 and 80 years with unilateral inguinal hernia undergoing Lichtenstein hernia repair were randomized to receive either prophylactic ilioinguinal neurectomy (group A) or ilioinguinal nerve preservation (group B) during operation. All operations were performed by surgeons specialized in hernia repair under local anesthesia or general anesthesia. The primary outcome was the incidence of chronic groin pain at 6 months. Secondary outcomes included incidence of groin numbness, postoperative sensory loss or change at the groin region, and quality of life measurement assessed by SF-36 questionnaire at 6 months. All follow-up and outcome measures were carried out by a designated occupational therapist at 1 and 6 months following surgery in a double-blinded manner. RESULTS: The incidence of chronic groin pain at 6 months was significantly lower in group A than group B (8% vs. 28.6%; P = 0.008). No significant intergroup differences were found regarding the incidence of groin numbness, postoperative sensory loss or changes at the groin region, and quality of life measurement at 6 months after the operation. CONCLUSIONS: Prophylactic ilioinguinal neurectomy significantly decreases the incidence of chronic groin pain after Lichtenstein hernia repair without added morbidities. It should be considered as a routine surgical step during the operation.

Adolescent↗
PubMed2006

Video-assisted thoracic surgery for early stage lung cancer - can short-term immunological advantages improve long-term survival?

The development of video-assisted thoracic surgery (VATS) in the past decade has changed the way many pulmonary conditions are being treated. VATS has gained popularity among clinicians due to faster recovery following surgery, less postoperative pain and better cosmesis. It is well known that surgical trauma can induce a systemic inflammatory response and affect postoperative systemic immunity. Minimal access VATS has been shown to be associated with a reduced postoperative systemic inflammatory response. Recent evidence suggests VATS is also associated with better cellular immunity, and produces less immunochemokine disturbance following surgery, when compared with the thoracotomy approach. Circulating natural killer (NK) cell numbers and levels of insulin growth factor binding protein (IGFBP) are found to be higher, and plasma levels of matrix metalloproteinases are lower following VATS than that after thoracotomy. Maintenance of immune function with VATS may have important clinical implications in lung cancer surgery.

Follow-Up Studies↗
PubMed2005

Is minimal access surgery for cancer associated with immunologic benefits?

Minimal-access surgical techniques have been shown to be beneficial to patients in terms of shorter convalescence, reduced pain, and improved cosmesis. Although systemic immune function is better preserved following laparoscopic procedures when compared with their respective open approaches, CO2 pneumoperitoneum may significantly affect local (i.e., infra-abdominal) cellular immunity by reducing regional macrophage function. Results to date are conflicting with regard to the impact of closed and open methods on intraabdominal immunity. Impaired cellular immunity after CO2 pneumoperitoneum may have significant undesirable intra-abdominal effects on tumor surveillance after oncological surgery; however, at present, there is no clinical evidence to support this position. The VATS techniques avoid the use of CO2 insufflation, which may offer some advantages from the immune function perspective over laparoscopic procedures accomplished with CO2 pneumoperitoneum. Better preservation of early postoperative cellular immune function and attenuated disturbance in the inflammatory mediators are likely contributing factors to the clinical benefits that follow laparoscopic surgery and VATS. Larger multi-center randomized trials are needed to confirm the potential benefits of minimal-access surgery on patient survival after cancer surgery. Future research should focus on the effects of minimal-access surgery on other mediators (such as MMP-9, IGFBP-3, IL-12, IL-17, and IL-23) that may be important in tumor cell dissemination, deposition, and propagation in the early postoperative period. Furthermore, additional searches for other factors or mediators, heretofore unrecognized, should be carried out. Such studies will, we hope, increase our knowledge and understanding of the impact of surgery on immune and other physiologic functions.

Humans↗
PubMed2005

Optimum duration of prophylactic antibiotics in acute non-perforated appendicitis.

BACKGROUND: The effect of extended prophylactic antibiotic therapy on postoperative infective complications such as wound infection and intra-abdominal abscess for non-perforated appendicitis is poorly defined. METHODS: In a randomized controlled trial of 269 patients aged 15-70 years with non-perforated appendicitis undergoing open appendicectomy; 92 received single dose preoperative (group A), 94 received three-dose (group B) and 83 received 5-day perioperative (group C) regimens of cefuroxime and metronidazole. Postoperative infective complication was the primary endpoint. Secondary outcomes included length of hospital stay and complications related to antibiotic therapy. RESULTS: The rate of postoperative infective complication was not significantly different among the groups (6.5% group A, 6.4% group B, 3.6% group C). The duration of antibiotic therapy had no significant effect on the length of hospital stay. Complications related to antibiotic treatment were significantly more common for 5-day perioperative antibiotic group (C) compared with single dose preoperative antibiotic group (A) (P = 0.048). CONCLUSION: Single dose of preoperative antibiotics is adequate for prevention of postoperative infective complications in patients with non-perforated appendicitis undergoing open appendicectomy. Prolonging the use of antibiotics can lead to unnecessary antibiotic related complications.

Adolescent↗
PubMed2005

Post-pneumonectomy empyema: current management strategies.

Post-pneumonectomy empyema is an uncommon but potentially life-threatening complication. It has a strong association with bronchopleural fistula, which acts as a continued source of infection into the thoracic cavity. Numerous risk factors have been identified and strategies formulated to minimize its occurrence. When bronchopleural fistula occurs, its treatment depends on several factors including extent of dehiscence, degree of pleural contamination and general condition of the patient. Early diagnosis and assessment with appropriate investigations, and aggressive therapeutic strategies are paramount in controlling sepsis, facilitating closure of fistula, and sterilization of the closed pleural space. Recent success with repeat debridement has made routine space obliteration not mandatory in management. The development of minimal-access interventions including video-assisted thoracic surgery, endoscopic application of tissue glue and stenting may be additional tools to complement conventional surgery in post-pneumonectomy empyema management.

Bronchial Fistula↗
PubMed2004

Video-assisted thoracic surgery for primary spontaneous hemopneumothorax.

OBJECTIVE: Video-assisted thoracic surgery (VATS) has changed the way we manage a number of thoracic conditions. This study presents near over a decade of experience from our institution on management of spontaneous hemopneumothorax (SHP), with particular reference to the use of VATS. METHODS: Retrospective review between March 1988 and December 2002 with 793 patients treated for spontaneous pneumothorax, 30 (3.8%) patients had SHP. The clinical features, indications for surgery and outcomes are discussed. RESULTS: All 30 SHP patients were male with mean age of 25 years. Signs of significant hypovolemia occurred in 4 patients, 3 required blood transfusion. Mean initial blood drainage from tube thoracostomy was 594 ml. All SHP patients received surgery (5 thoracotomies, 25 VATS). Active bleeding was identified in 16 patients; 12 from torn apical vascular adhesion band and 4 from vascular bleb. Postoperative complications after thoracotomy include 2 chest infections and 1 air leak, while VATS had 1 chest infection and 1 air leak (P=0.022). Mean postoperative hospital stay following VATS was 3.9 days and thoracotomy 7.5 days (P=0.0021). There is no recurrence of pneumothorax or SHP during mean follow-up of 21 months. CONCLUSION: SHP can be life threatening and is a cause for patients presenting with unexplained signs of significant hypovolemia. Surgery in the form of VATS should be considered early in the management of SHP, with potentially less postoperative complications and shorter postoperative hospital stay compared with open thoracotomy.

Adolescent↗
PubMed2004

Randomized, double-blinded, placebo-controlled trial of intravenously administered hyoscine N-butyl bromide in patients undergoing colonoscopy with patient-controlled sedation.

BACKGROUND: A prospective, double-blinded, placebo-controlled randomized trial was conducted to investigate the effect of the antispasmodic hyoscine N-butyl bromide (Buscopan) during colonoscopy. METHODS: A total of 120 patients undergoing colonoscopy were randomized to receive either 40 mg of hyoscine N-butyl bromide (n=60) or normal saline solution (n=60) intravenously as premedication. Colonoscopy was performed under patient-controlled sedation. Outcome measures included cecal intubation and total procedure time, demanded and administered doses of patient-controlled sedation, spasm score, pain score, endoscopist satisfaction score, patient willingness to repeat colonoscopy, and vital signs (blood pressure, pulse rate) during colonoscopy. RESULTS: Mean cecal intubation time in the hyoscine N-butyl bromide group was significantly longer than the control group (12.20 vs. 9.74 minutes; p=0.04; but correction for multiple testing of data removed this significance). The use of hyoscine N-butyl bromide was associated with a significantly lower endoscopist mean satisfaction score (6.47 vs. 7.30; p=0.04; but correction for multiple testing of data removed this significance), higher demanded and administered mean doses of patient-controlled sedation (respectively, 34.80 and 7.25 vs. 24.20 and 5.87; p=0.045; p=0.04, respectively; but correction for multiple testing of data removed these findings of significance), fewer patients willing to repeat colonoscopy (60% vs. 83.9%; p=0.005), and more hemodynamic instability (p<0.001) when compared with the control group. No significant difference was found in the total procedure time, spasm score, or pain score. CONCLUSIONS: Premedication with intravenously administered hyoscine N-butyl bromide impedes colonoscope insertion and causes greater patient discomfort, as well as hemodynamic instability.

Adult↗
PubMed2003

The impact of thoracic surgical access on early shoulder function: video-assisted thoracic surgery versus posterolateral thoracotomy.

OBJECTIVE: Whether video-assisted thoracic surgery (VATS) is associated with less shoulder dysfunction when compared with posterolateral thoracotomy (PLT) remains unclear. We therefore conducted this prospective study to assess the shoulder function in patients following major lung resection using either the VATS or PLT approach. METHODS: Twenty-nine consecutive patients were prospectively recruited into the study. Eighteen patients underwent major lung resection through VATS (VATS group) and 11 patients through PLT (open group). Shoulder function was measured preoperatively, and postoperatively at 1 week, 1 month and at 3 months. All assessments were done by two experienced physiotherapists using the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form. RESULTS: Shoulder strength was significantly better preserved in the VATS group at 1 week after surgery when compared with the PLT group (92 versus 81% of preoperative value; P=0.024). VATS patients also had better range of motion especially with respect to external rotation at 1 week (98 versus 91%; P=0.015) and forward elevation at 1 month (98 versus 93%; P=0.024) and 3 months after surgery (100 versus 96%; P=0.021). Analgesic requirement was significantly less in the VATS group postoperatively at 1 week (P=0.009) and 1 month (P=0.004). CONCLUSIONS: VATS major lung resection is associated with significantly less shoulder dysfunction and pain medication requirement in the early postoperative period when compared to the PLT approach.

Activities of Daily Living↗