Andrew D MacCormick

Publications (12)28.91 Total impact

• Article: Gentamicin-Collagen Implants to Reduce Surgical Site Infection: Systematic Review and Meta-analysis of Randomized Trials.

  Wai Keat Chang, Sanket Srinivasa, Andrew D Maccormick, Andrew G Hill
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  ABSTRACT: OBJECTIVE:: To determine whether gentamicin-impregnated collagen sponges (gentamicin-collagen implants) decrease the incidence of surgical site infection (SSI). BACKGROUND:: SSIs cause substantial morbidity and increase the costs of healthcare. Antibiotic prophylaxis is a cornerstone of SSI reduction. Prophylactic local delivery of antibiotics with novel biodegradable drug carrier systems, such as the gentamicin-collagen implant, is a potential avenue for SSI reduction. Gentamicin-collagen implants have been previously assessed in multiple randomized controlled trials (RCTs) with conflicting results. Therefore, a systematic review and meta-analysis of all relevant RCTs was conducted to determine whether gentamicin-collagen implants reduce SSI. METHODS:: Major medical databases and trial registers were searched for published and unpublished RCTs. The endpoint of interest was the incidence of SSI. A random effects model was used and pooled estimates were reported as odds ratios (ORs), with the corresponding 95% confidence interval (CI). A subset analysis by incision type was planned a priori. RESULTS:: Fifteen RCTs encompassing a total of 6979 patients were included in the final analysis. The included studies were of moderate to high quality. Gentamicin-collagen implants significantly reduced SSI [OR = 0.51; 95% CI: 0.33-0.77; P = 0.001; number needed to treat (NNT) = 21; I = 75%]. These results were seen in subset analysis of clean (OR = 0.53; 95% CI: 0.33-0.87; P = 0.01; NNT = 30) and clean-contaminated surgery (OR = 0.43; 95% CI: 0.20-0.93; P = 0.03; NNT = 9) specifically. CONCLUSIONS:: Gentamicin-collagen implants decrease the rate of SSI.
  Annals of surgery 03/2013; · 7.90 Impact Factor
• Article: Effect of Preoperative Exercise on Cardiorespiratory Function and Recovery After Surgery: a Systematic Review.

  Daniel P Lemanu, Primal P Singh, Andrew D Maccormick, Bruce Arroll, Andrew G Hill
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  ABSTRACT: BACKGROUND: This systematic review aims to investigate the extent to which preoperative conditioning (PREHAB) improves physiologic function and whether it correlates with improved recovery after major surgery. METHODS: An electronic database search identified randomized controlled trials (RCTs) investigating the safety and efficacy of PREHAB. The outcomes studied were changes in cardiorespiratory physiologic function, clinical outcomes (including length of hospital stay and rates of postoperative complications), and measures of changes in functional capacity (physical and psychological). RESULTS: Eight low- to medium-quality RCTs were included in the final analysis. The patients were elderly (mean age >60 years), and the exercise programs were significantly varied. Adherence to PREHAB was low. Only one study found that PREHAB led to significant improvement in physiologic function correlating with improved clinical outcomes. CONCLUSION: There are only limited data to suggest that PREHAB confers any measured physiologic improvement with subsequent clinical benefit. Further data are required to investigate the efficacy and safety of PREHAB in younger patients and to identify interventions that may help improve adherence to PREHAB.
  World Journal of Surgery 01/2013; · 2.36 Impact Factor
• Article: Optimizing perioperative care in bariatric surgery patients.

  Daniel P Lemanu, Sanket Srinivasa, Primal P Singh, Sharon Johannsen, Andrew D MacCormick, Andrew G Hill
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  ABSTRACT: Enhanced recovery after surgery (ERAS) programs have been shown to minimise morbidity in other types of surgery, but comparatively less data exist investigating ERAS in bariatric surgery. This article reviews the existing literature to identify interventions which may be included in an ERAS program for bariatric surgery. A narrative literature review was conducted. Search terms included 'bariatric surgery', 'weight loss surgery', 'gastric bypass', 'ERAS', 'enhanced recovery', 'enhanced recovery after surgery', 'fast-track surgery', 'perioperative care', 'postoperative care', 'intraoperative care' and 'preoperative care'. Interventions recovered by the database search, as well as interventions garnered from clinical experience in ERAS, were used as individual search terms. A large volume of evidence exists detailing the role of multiple interventions in perioperative care. However, efficacy and safety for a proportion of these interventions for ERAS in bariatric surgery remain unclear. This review concludes that there is potential to implement ERAS programs in bariatric surgery.
  Obesity Surgery 04/2012; 22(6):979-90. · 3.29 Impact Factor
• Article: Single-stage laparoscopic sleeve gastrectomy: safety and efficacy in the super-obese.

  Daniel P Lemanu, Sanket Srinivasa, Primal P Singh, Andrew D MacCormick, Stephanie Ulmer, Jon Morrow, Andrew G Hill, Richard Babor, Habib Rahman
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  ABSTRACT: Laparoscopic sleeve gastrectomy (LSG) is increasingly used as a single-stage bariatric procedure. However, its safety and efficacy in super-obese patients (body mass index [BMI] > 50 kg/m(2)) is less well defined. This series reports on 400 consecutive patients who underwent LSG at our institution, to evaluate safety and efficacy in the super-obese. We performed a retrospective review of prospectively collected data on 400 consecutive patients who underwent LSG at our institution. We analyzed baseline demographic data, median length of hospital stay, complications, length of follow-up, weight loss, and comorbidity resolution. We graded complications according to the Clavien-Dindo classification system. We classified patients as super-obese and non-super-obese and compared outcomes between groups. We used the two-tailed t-test and Fisher's exact test as necessary. There were 400 patients, 291 of whom were female (73%). The mean age was 44 y (standard deviation [SD] ± 9 y). The mean preoperative weight and BMI were 140 kg (SD ± 31 kg) and 49 kg/m(2) (SD ± 9 kg/m(2)), respectively. There were 67 complications (16%) in total. The major complication rate was 7.2%, with one recorded death. The median length of hospital stay was 3 d, and the mean follow-up period was 1 y. A total of 170 patients (43%) were super-obese, with a mean preoperative BMI of 56 kg/m(2) (SD ± 5 kg/m(2)). The mean absolute weight loss (59 versus 36.7 kg; P < 0.01) and percentage excess weight loss (58.9% versus 45.9%; P < 0.01) was significantly higher in the super-obese. The mean postoperative BMI for super-obese patients was 38.9 kg/m(2). There was no difference between groups in the incidence of major complications (8.2% versus 6.5%; P = 0.56). Laparoscopic sleeve gastrectomy is safe and effective in the super-obese, with acceptable weight loss and no increase in the major complication rate.
  Journal of Surgical Research 03/2012; 177(1):49-54. · 2.25 Impact Factor
• Article: Statins in abdominal surgery: a systematic review.

  Primal P Singh, Sanket Srinivasa, Daniel P Lemanu, Andrew D Maccormick, Andrew G Hill
  Journal of the American College of Surgeons 03/2012; 214(3):356-66. · 4.55 Impact Factor
• Article: Laparoscopic sleeve gastrectomy: its place in bariatric surgery for the severely obese patient.

  Daniel P Lemanu, Sanket Srinivasa, Primla Prima Singh, Andrew G Hill, Andrew D MacCormick
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  ABSTRACT: Laparoscopic sleeve gastrectomy (LSG) was initially used as a staging procedure for high-risk patients undergoing bariatric surgery. However, it is now being increasingly favoured as a single-stage procedure. This article discusses the use of LSG as a single-stage procedure for the treatment of obesity and related comorbidities. A literature review was conducted using specific search terms in multiple medical databases. Early and mid-term weight loss results show that LSG is comparable to more established bariatric procedures. It also produces satisfactory resolution of obesity related comorbidities such as type two diabetes mellitus (T2DM). There are minimal published outcome data to assess its long-term effectiveness and safety. This is particularly true in super-obese patients with current data suggesting less satisfactory acheivement of a normal BMI in this group of patients. LSG is safe and produces satisfactory weight loss and comorbidity resolution in the early and mid-term period. However, further data are required to assess its long-term effectiveness as well as its effectiveness in super-obese patients.
  The New Zealand medical journal 01/2012; 125(1359):41-9.
• Article: Priority assessment of patients for elective general surgery: game on?

  Andrew D MacCormick, Chuan P Tan, Bryan R Parry
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  ABSTRACT: Clinical priority assessment criteria (CPAC) are used to generate a score by which patients are prioritized and rationed for elective surgery. It is widely believed that surgeons elevate scores to ensure their patients' acceptance for elective surgery, colloquially called gaming. The purpose of the present paper was therefore to investigate whether there was a temporal trend to an increase in the assigned priority score from the inception of CPAC to the present. Priority and weighted inlier equivalent separations (WIES) scores between 23 April 1999 and 23 July 2002 were collected for elective general surgical cases at Auckland Hospital. A total of 5440 cases was retrospectively analysed using multiple regression techniques. Priority score was included as the dependent variable and time as an independent variable. Any change in case complexity over that period was accounted for by including the WIES score as a covariate. Multiple regression was undertaken for the combined surgeons and for individuals. The combined model was statistically significant but accounted for only 17% of the priority score variance. An increase of one WIES unit leads to an increase of 2.7 in priority score (P=0.0001). The relationship of priority score with time was dependent on the surgeon performing the prioritization. However, only half the surgeons had individual models that indicated gaming. The results show that gaming is occurring but that not all surgeons participate in this. The difference between surgeons' participation in gaming is a potential source of practice variation in the prioritization process.
  ANZ Journal of Surgery 04/2004; 74(3):143-5. · 1.25 Impact Factor
• Article: Waiting time thresholds: are they appropriate?

  Andrew D MacCormick, B R Parry
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  ABSTRACT: The introduction of health reforms in New Zealand included the setting of an arbitrary waiting time threshold of 6 months for surgery. The aim of the present study was to investigate the differences in waiting times for different diagnoses in elective general surgery, and the interplay between diagnoses and waiting time thresholds. A survival curve analysis of 918 patients placed on the elective general surgical waiting lists was conducted. This was undertaken in a tertiary level hospital in New Zealand before the implementation of the waiting time thresholds. The difference between diagnoses of time waited for elective surgery (plotted on survival curves), and hazard function for patients waiting at 180, 360 and 540 days, was investigated. Survival curves for malignancy, cholelithiasis, hernias and anorectal disease were different on log-rank test (P < 0.001). Those with a diagnosis of malignancy show that at 180 days the hazard function was 0.0049 but by 360 days had dropped to zero. With hernias and anorectal disease, the drop to zero appeared to be delayed until 540 days; however, the confidence intervals at 360 days included zero. In the case of cholelithiasis, the hazard functions indicate surgery occurring until 540 days. There are different waiting time thresholds for different surgical illnesses. Setting a universal waiting time for elective surgery is not supported.
  ANZ Journal of Surgery 12/2003; 73(11):926-8. · 1.25 Impact Factor
• Article: Prioritizing patients for elective surgery: a systematic review.

  Andrew D MacCormick, Wayne G Collecutt, Bryan R Parry
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  ABSTRACT: Priority scoring tools are moot as means for dealing with burgeoning elective surgical waiting lists. There is ongoing development work in New Zealand, Canada and the UK. This emerging international perspective is invaluable in determining the application of these tools and addressing any pitfalls. A systematic electronic literature review was performed. Information was also retrieved using a search of reference lists of all papers included in the review and contact with those who were involved in the development of such criteria. The ethical basis of prioritization differed among priority scoring tools and in a number was not stated. The majority of tools covered criteria for specific procedures. Delphi consensus methods and regression were the predominant methods for -deter-mining -specific criteria. Authors' opinions were the main source of generic criteria. Linear and non-linear models or matrices sum-mated criteria. There is debate over the ethical basis for prioritization. It is a concern that it is not addressed in many studies. The development of generic criteria showed a dearth of consensus approaches that represents a significant gap in our knowledge. On the aspects of summation and weighting, the impact of assumptions on the prioritization of patients may not have been fully explored.
  ANZ Journal of Surgery 09/2003; 73(8):633-42. · 1.25 Impact Factor
• Article: Prioritizing patients for elective surgery: clinical judgement summarized by a Linear Analogue Scale.

  Andrew D MacCormick, Lindsay D Plank, Elizabeth M Robinson, Bryan R Parry
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  ABSTRACT: The New Zealand health reforms have resulted in the requirement that surgeons utilize Clinical Priority Access Criteria (CPAC) to ration patient access to elective surgery. The validity of the tools used as CPAC has been challenged. An alter-native tool, the Linear Analogue Scale (LAS), is therefore used in our institution. Our objectives were to determine the variables that influence the priority score generated using the LAS, and the length of time waited by patients awaiting general surgical procedures. A cohort of 918 patients who were listed for elective general surgical procedures at Auckland Hospital, Auckland, New Zealand between 1 July 1998 and 31 March 1999 were studied. Patients were given a priority score generated using the LAS. For each patient, the time from assessment until his or her procedure was documented. Linear and logistic regression models were used to investigate variables (age, gender, diagnosis and surgical team) that influence priority score. Cox proportional hazards models were used to investigate variables (priority score, age, gender, and diagnosis) that influence the length of time waited. Graphical presentation showed a pattern of priority scores falling into 'bands' for different diagnoses. Diagnosis, and to a lesser extent surgical team, influenced priority score. Survival analysis showed 'time waited' to be influenced by priority score, diagnosis, and patient age and gender. The LAS may have a useful role in the difficult sphere of patient prioritization. Its strength lies in its simplicity. Further investigation of reliability and effect on patient outcomes is required.
  ANZ Journal of Surgery 10/2002; 72(9):613-7. · 1.25 Impact Factor
• Article: Necrotizing fasciitis: analysis of 48 cases in South Auckland, New Zealand.

  Albert Tiu, Richard Martin, Peter Vanniasingham, Andrew D MacCormick, Andrew G Hill
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  ABSTRACT: To assess the presentation, management and risk factors for mortality in necrotizing fasciitis at Middlemore Hospital in South Auckland, New Zealand. A retrospective review of the medical records of patients presenting to Middlemore Hospital over a 6-year period (1997-2002) with a diagnosis of necrotizing fasciitis. Forty eight patients were identified. There were 27 men and 21 women whose age ranged from 19 to 80 years (median 51 years) at presentation. Maori and Pacific Islanders accounted for 64% of total admissions despite making up only 31% of the referral population. Streptococcus Pyogenes was the most common bacterial isolate (54%). 31% of patients had polymicrobial infections. Sixty-two per cent of cases involved extremities. The median number of operations and length of stay were 4 and 31 days, respectively. Overall mortality was 29%. In multivariate analysis, delay in surgical intervention (P = 0.015) and diabetes mellitus (P = 0.023) were found to be associated with increased mortality. Ethnicity, sex, type of pathogen, site of infection and increasing age did not affect mortality. Necrotizing fasciitis remains a significant problem in our community especially in the Maori and Pacific population. Early surgical debridement decreases mortality rates.
  ANZ Journal of Surgery 75(1-2):32-4. · 1.25 Impact Factor
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  Available from: internetgroup.ca

  Article: Judgment analysis of surgeons' prioritization of patients for elective general surgery.

  Andrew D MacCormick, Bryan R Parry
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  ABSTRACT: Access to elective general surgery in New Zealand is governed by clinicians' judgment of priority using a visual analog scale (VAS). This has been criticized as lacking reliability and transparency. Our objective was to describe this judgment in terms of previously elicited cues. We asked 60 general surgeons in New Zealand to assess patient vignettes using 8 VAS scales to determine priority. They then conducted judgment analysis to determine agreement between surgeons. Cluster analysis was performed to identify groups of surgeons who used different cues. Multiple regression for the combined surgeons was undertaken to determine the predictability of the 8-scale VAS. Agreement between surgeons was poor (ra=0.48). The cause of poor agreement was mostly due to poor consensus (G) between surgeons in how they weighted criteria. Using cluster analysis, we classified the surgeons into 2 groups: 1 took more account of quality of life and diagnosis, whereas the other group placed more weight on the influence of treatment. The 8-scale VAS showed good predictability in assigning a priority score (R2=0.66). The level of agreement reflects surgeons' practice variation. This is exemplified by 2 distinct surgeon groups that differ in how criteria were weighted.
  Medical Decision Making 26(3):255-64. · 2.33 Impact Factor