Publications by authors named "Michael K-Y Hong"

15 Publications

  • Page 1 of 1

Positive lateral pelvic lymph nodes in low rectal cancer: should we change our practice now?

ANZ J Surg 2021 05 1;91(5):947-953. Epub 2021 Apr 1.

Colorectal Surgery Unit, Western Health, Melbourne, Victoria, Australia.

Background: The role of lateral lymph node dissection (LLND) in the treatment of patients with low rectal cancer with enlarged lateral lymph nodes (LLN+) is under investigation. Enthusiasm for LLND stems from a perceived reduction in local recurrence (LR). We aimed to compare the LR rate for LLN+ patients with LLN- patients, treated with neoadjuvant chemoradiotherapy (nCRT) and surgery, in a hospital that does not perform LLND.

Methods: A retrospective study of all patients with clinical stage 3 low rectal cancer who completed nCRT and surgery between 2008 and 2017 at Western Health was performed. Outcomes for LLN+ patients were compared with LLN- patients. The primary outcome was LR. Secondary outcomes included distant metastases, disease-free survival and overall survival.

Results: There were 110 patients treated for stage 3 low rectal cancer over 10 years. There was no significant difference in the LR rate, with one LR from 28 LLN+ patients and one LR from 82 LLN- patients (4% versus 1.2%, P = 0.44). There were no significant differences in median disease-free survival (41 versus 52 months, P = 0.19) or mean overall survival (62 versus 60 months, P = 0.80). Of all patients studied, 21% developed distant metastases.

Conclusion: LR after nCRT and surgery in patients with stage 3 rectal cancer is rare, irrespective of lateral pelvic node status. These data, along with the uncertain benefit and known risks of LLND, supports the continued use of standard therapy in these patients. Strategies to address distant failure in these patients should be explored.
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http://dx.doi.org/10.1111/ans.16779DOI Listing
May 2021

State-wide outcomes in elective rectal cancer resection: is there a case for centralization in Victoria?

ANZ J Surg 2019 12 4;89(12):1642-1646. Epub 2019 Dec 4.

Colorectal Surgery Unit, Western Health, Melbourne, Victoria, Australia.

Background: The role of service centralization in rectal cancer surgery is controversial. Recent studies suggest centralization to high-volume centres may improve postoperative mortality. We used a state-wide administrative data set to determine the inpatient mortality for patients undergoing elective rectal cancer surgery and to compare individual hospital volumes.

Methods: The Victorian Admitted Episodes Dataset was explored using the Dr Foster Quality Investigator tool. The inpatient mortality rate, 30-day readmission rate and the proportion of patients with increased length of stay were measured for all elective admissions for rectal cancer resections between 2012 and 2016. A peer group of 14 hospitals were studied using funnel plots to determine inter-hospital variation in mortality. Procedure types were compared between the groups.

Results: There were 2241 elective resections performed for rectal cancer in Victoria over 4 years. The crude inpatient mortality rate was 1.1%. There were no significant differences in mortality among 14 hospitals within the peer group. The number of elective resections over 4 years ranged from 14 to 136 (median 65) within these institutions. Ultralow anterior resection was the commonest procedure performed.

Conclusion: Inpatient mortality after elective rectal cancer surgery in Victoria is rare and compares favourably internationally. Based on inpatient mortality alone, there is no compelling evidence to further centralize elective rectal cancer surgery in Victoria. More work is needed to develop data sets with oncological information capable of providing accurate complete state-wide data which will be essential for future service planning, training and innovation.
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http://dx.doi.org/10.1111/ans.15546DOI Listing
December 2019

Complete state-wide outcomes in elective colon cancer surgery.

ANZ J Surg 2018 11 15;88(11):1174-1177. Epub 2018 Oct 15.

Colorectal Surgery Unit, Western Health, Melbourne, Victoria, Australia.

Background: Maintaining high standards in colon cancer surgery requires the measurement of quality indicators and the re-allocation of resources to address deficiencies. We used state-wide administrative data to determine the inpatient mortality for patients undergoing elective colon cancer surgery and to compare individual hospital rates.

Methods: The Dr Foster Quality Investigator Tool was used to explore the Victorian Admitted Episodes Dataset for elective admissions for colon cancer surgery between 2012 and 2016. The inpatient mortality rate, 30-day readmission rate and the proportion of patients with increased length of stay were measured. Risk-adjusted rates were used to compare public and private hospitals. A peer group of 14 hospitals were studied using funnel plots to determine inter-hospital variation in mortality.

Results: There were 6120 colectomies performed for colon cancer in Victoria over 3 years. The crude inpatient mortality rate was 1.3%. It was significantly higher in public than private hospitals, even after risk adjustment. Variation in crude mortality was demonstrated among 14 selected hospitals. The lowest volume hospitals had significantly higher inpatient mortality rates. Right hemicolectomy was the commonest procedure performed.

Conclusion: Using an efficient method of complete state-wide data capture, we have demonstrated that the inpatient mortality rate after elective colon cancer surgery in Victoria is low. However, complexity remains around the interpretation of inter-hospital variation, defining outliers, and comparing outcomes between public and private hospitals. Resolving these complexities and defining additional quality indicators remain a priority in the use of administrative data to audit the quality of colon cancer care.
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http://dx.doi.org/10.1111/ans.14872DOI Listing
November 2018

Administrative data: what surgeons should know about big data.

ANZ J Surg 2017 Sep;87(9):650-651

Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Victoria, Australia.

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http://dx.doi.org/10.1111/ans.13978DOI Listing
September 2017

Appendiceal intussusception causing appendicitis.

ANZ J Surg 2018 12 15;88(12):E851-E852. Epub 2017 Mar 15.

Colorectal Surgery, Bankstown-Lidcombe Hospital, The University of New South Wales, Sydney, New South Wales, Australia.

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http://dx.doi.org/10.1111/ans.13931DOI Listing
December 2018

International Variation in Emergency Operation Rates for Acute Diverticulitis: Insights into Healthcare Value.

World J Surg 2017 08;41(8):2121-2127

Department of Surgery, The University of Melbourne, Melbourne, Australia.

Background: International comparison of outcomes of surgical diseases has become a global focus because of widespread concern over surgical quality, rising costs and the value of healthcare. Acute diverticulitis is a common disease potentially amenable to optimization of strategies for operative intervention. The aim was to compare the emergency operative intervention rates for acute diverticulitis in USA, England and Australia.

Methods: Unplanned admissions for acute diverticulitis were found from an international administrative dataset between 2008 and 2014 for hospitals in USA, England and Australia. The primary outcome measured was emergency operative intervention rate. Secondary outcomes included inpatient mortality and percutaneous drainage rate. Multivariable analysis was performed after development of a weighted comorbidity scoring system.

Results: There were 15,150 unplanned admissions for acute diverticulitis. The emergency operative intervention rates were 16, 13 and 10% for USA, England and Australia. The percutaneous drainage rate was highest in USA at 10%, while the mortality rate was highest in England at 2.8%. The propensity for emergency operative intervention was higher in USA (OR 1.45, p < 0.001) and England (OR 1.49, p < 0.001) than in Australia. The risk of 7-day mortality was higher in England than in Australia (OR 2.79, p < 0.001). Percutaneous drainage was associated with reduced 7-day mortality risk.

Conclusion: Australia has a lower propensity for emergency operative intervention, while England has a greater risk of mortality for acute diverticulitis. International variations raise the issue of healthcare value in terms of differing resource use and outcomes.
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http://dx.doi.org/10.1007/s00268-017-3965-zDOI Listing
August 2017

Triradiate caecal fold: Is it a useful landmark for caecal intubation in colonoscopy?

World J Gastrointest Endosc 2015 Sep;7(13):1103-6

Andrew Finlayson, Raaj Chandra, Ian A Hastie, Ian T Jones, Susan Shedda, Michael K-Y Hong, Aileen Yen, Ian P Hayes, Colorectal Surgery Unit, Department of General Surgical Specialties, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia.

Aim: To determine the frequency of identification of the triradiate fold during colonoscopy and evaluate its reliability as a marker of caecal intubation.

Methods: One hundred consecutive patients undergoing colonoscopy in a tertiary hospital colorectal unit from May to September 2013 were studied. Video documentation of the caecum was recorded and shown to consultant colorectal surgeons on the unit. Each reviewer was asked through a series of questions to independently identify the triradiate fold. The main outcome was the frequency of visualisation of the triradiate fold in the caecum.

Results: The triradiate fold was seen on average in 18% of cases, but inter-observer agreement was poor. There were only four patients (4%) in which all reviewers agreed on the presence of a triradiate fold. In patients who had undergone previous appendicectomy, the appendiceal orifice was less frequently seen compared with patients who had not undergone appendicectomy.

Conclusion: The triradiate fold is infrequently seen during colonoscopy and is therefore an unreliable landmark of caecal intubation.
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http://dx.doi.org/10.4253/wjge.v7.i13.1103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4580952PMC
September 2015

Operative intervention rates for acute diverticulitis: a multicentre state-wide study.

ANZ J Surg 2015 Oct 22;85(10):734-8. Epub 2015 Apr 22.

Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia.

Background: Acute colonic diverticulitis is placing an increasing strain on our health care resources. Measurement of the problem is difficult at a regional level, yet essential to improve and optimize treatment of this condition. Therefore, we aimed to use Australian state-level administrative data to determine the current practice and outcomes in major metropolitan hospitals.

Methods: Coding algorithms designed to increase the yield and accuracy of administrative data were used to find emergency admissions from the Victorian Admitted Episodes Dataset. Eight tertiary referral centres with specialist colorectal services from 2009 to 2013 were studied. Key metrics including the operative intervention rate were measured.

Results: There were 2829 emergency admissions for acute diverticulitis across 4 years in eight hospitals, with 724 being complicated. The emergency operative intervention rate was 10.4%, with a third of admissions for complicated diverticulitis having an operation. Hartmann's procedure was the most commonly performed emergency operation, accounting for 72% of resections. Patient characteristics were consistent across the hospitals, including a median length of stay of 3 and 6 days for uncomplicated and complicated diverticulitis, respectively.

Conclusion: Hartmann's procedure is currently the most common emergency operation for acute complicated diverticulitis in Victorian metropolitan hospitals. Our practice and outcomes can be measured meaningfully using administrative data.
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http://dx.doi.org/10.1111/ans.13126DOI Listing
October 2015

Using the 4-hour Post-ERCP amylase level to predict post-ERCP pancreatitis.

JOP 2011 Jul 8;12(4):372-6. Epub 2011 Jul 8.

Department of Surgery, Northeast Health, Wangaratta, Australia.

Context: Post-ERCP pancreatitis is the most common complication of endoscopic retrograde cholangiopancreatography (ERCP). A simple method of predicting patients who are at risk of developing post-ERCP pancreatitis is needed to allow those at low risk to be discharged on the same day of their procedure. The aim of this study was to confirm that 4-hour post-ERCP serum amylase level is predictive of post-ERCP pancreatitis.

Patients: A study of 886 ERCPs performed at a single centre was conducted.

Main Outcome Measure: Four-hour amylase level was recorded, along with patient demographics, procedural details, presence of pancreatogram, and morbidity and mortality.

Results: Pancreatitis occurred in 4.4% of ERCPs. Hyperamylasaemia was found to be predictive of post-ERCP pancreatitis, with other risk factors being a younger age and pancreatogram. Hyperamylasaemia was also predictive of post-ERCP pancreatitis in the subgroup of patients who had undergone pancreatogram.

Conclusions: The 4-hour amylase level is a useful measure in the prediction of post-ERCP pancreatitis. Patients who have undergone pancreatogram should be admitted if 4-hour amylase level is greater than 2.5 times the upper limit of reference. Patients who have not undergone pancreatogram should be admitted if 4-hour amylase level is greater than 5 times the upper limit of reference.
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July 2011

Imaging the posterior interosseous artery with computed tomographic angiography: report of a rare anomaly and implications for hand reconstruction.

Ann Plast Surg 2010 Sep;65(3):300-1

Department of Anatomy and Cell Biology, The University of Melbourne, Parkville, Victoria, Australia.

Although the posterior interosseous artery flap has been used extensively for the coverage of dorsal hand defects, anatomic variations in the artery have been widely described. These variants have led to reports of flap failure or conversion to alternative salvage procedures. Preoperative imaging has been suggested in the past prior to posterior interosseous artery flaps as a result of these anatomic variations, particularly with Doppler ultrasound. We describe a new technique for imaging the posterior interosseous artery preoperatively, the use of computed tomography angiography, a highly accurate, noninvasive technique that can highlight the anatomy and allow safe planning for alternative reconstructive options in complex cases. A unique case is described where the posterior interosseous artery was completely absent throughout its course, and in which preoperative imaging was able to potentiate a good outcome.
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http://dx.doi.org/10.1097/SAP.0b013e3181c6a1bfDOI Listing
September 2010

A rare case of bilateral variations of upper limb arteries: brief review of nomenclature, embryology and clinical applications.

Surg Radiol Anat 2008 Oct 25;30(7):601-3. Epub 2008 Jun 25.

The Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Department of Anatomy and Cell Biology, University of Melbourne, Parkville, VIC, 3010, Australia.

We present a rare case of bilateral variations of upper limb arteries, namely, the superficial brachioulnoradial artery and the superficial brachioradial artery in a female cadaver. The superficial brachioulnoradial artery presented here is a variant of classical accounts. The superficial arteries replaced the typical arteries and were not additional vessels.
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http://dx.doi.org/10.1007/s00276-008-0380-zDOI Listing
October 2008

The angiosome territories of the spinal cord: exploring the issue of preoperative spinal angiography. Laboratory investigation.

J Neurosurg Spine 2008 Apr;8(4):352-64

The Jack Brockhoff Reconstructive Plastic Surgery Research Unit, The Royal Melbourne Hospital, Department of Anatomy and Cell Biology, University of Melbourne, Victoria, Australia.

Object: The angiosome concept has been the subject of extensive research by the senior author (G.I.T.), but its specific applicability to the spinal cord was hitherto unknown. The aim of this study was to see if the spinal cord vasculature followed the angiosome concept and to review the usefulness of preoperative spinal angiography in surgery for spinal disorders. Spinal cord infarction and permanent paraplegia may result from inadvertent interruption of the artery of Adamkiewicz. Spinal angiography, which may enable avoidance of this catastrophic complication, is still not commonly used.

Methods: Two fresh cadavers were injected with a gelatin-lead oxide mixture for detailed comparative study of spinal cord vasculature. One cadaver had insignificant vascular disease, whereas the other had extensive aortic atherosclerosis, presenting a unique opportunity for study. After removal from each cadaver, radiographs of the spinal cords were obtained, then photographed, and the vascular territories of the cords were defined.

Results: Four angiosome territories were defined: vertebral, subclavian, posterior intercostal, and lumbar. These vascular territories were joined longitudinally by true anastomotic channels along the anterior and posterior spinal cord. Anastomosis between the anterior and posterior vasculature was poor in the thoracolumbar region. The anterior cord relied on fewer feeder arteries than the posterior, and the anterior thoracolumbar cord depended on the artery of Adamkiewicz for its supply. In chronic aortic disease with intercostal artery occlusion at multiple levels, a rich collateral circulation supporting the spinal cord was found.

Conclusions: The arterial supply of the spinal cord follows the angiosome concept. The atherosclerotic specimen supports the suggestion that the blood supply is able to adapt to gradual vascular occlusion through development of a collateral circulation. Nevertheless, the spinal cord is susceptible to ischemia when faced with acute vascular occlusion. This includes inadvertent interruption of the artery of Adamkiewicz. The authors recommend the use of preoperative spinal angiography to prevent possible paraplegia in removal of thoracolumbar spinal tumors.
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http://dx.doi.org/10.3171/SPI/2008/8/4/352DOI Listing
April 2008

Angiosome territories of the nerves of the upper limbs.

Plast Reconstr Surg 2006 Jul;118(1):148-60

Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Victoria 3010, Australia.

Background: The use of free vascularized nerve grafts requires intimate knowledge of the blood supply of peripheral nerves. The authors aimed to demonstrate radiographically the topography of the upper limb nerves with their blood supply, and to examine them as an application of the angiosome concept. An angiosome is a three-dimensional block of composite tissue supplied by a single source artery.

Methods: This anatomical study involved the meticulous dissection of four fresh upper limb specimens injected intraarterially with a gelatin-lead oxide mixture. The nerves were tagged circumferentially with copper wire and radiographs were taken of the nerves with their arterial blood supply. The median, ulnar, radial, musculocutaneous, and axillary nerves were examined.

Results: The authors showed that the nerves of the upper limb were supplied segmentally by source vessels, which reinforced the angiosome concept. The suitability of each nerve for harvest in free vascularized nerve transfer was assessed according to its pattern of blood supply.

Conclusions: The authors' work has a wide range of clinical applications and provides an anatomical basis for neurovascular and neurocutaneous flaps and free vascularized nerve grafting.
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http://dx.doi.org/10.1097/01.prs.0000221075.91038.08DOI Listing
July 2006

An uncommon form of the rare extensor carpi radialis accessorius.

Ann Anat 2005 Mar;187(1):89-92

Reconstructive Plastic Surgery Research Unit, Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Vic. 3010, Australia.

Two accessory muscles were found in the lateral compartment of the forearm while dissecting a 92-year-old female cadaver. One of these originated from the extensor carpi radialis brevis, became tendinous and travelled between the two radial extensor tendons. It inserted independently into the second metacarpal bone, and may be regarded as an extensor carpi radialis intermedius. The other accessory muscle originated from the extensor carpi radialis longus, passed superficially over the parent tendon and inserted into the abductor pollicis brevis. This variation appeared to be a rare extensor carpi radialis accessorius, an additional muscle, which usually arises from below the extensor carpi radialis longus and inserts into the first metacarpal bone. Various forms of the accessorius have been described previously, including one that inserts into the abductor pollicis brevis. The tendon of the accessory muscle described in this study passed through its own dorsal tunnel under the extensor retinaculum, making it an uncommon form of the rare accessorius.
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http://dx.doi.org/10.1016/j.aanat.2004.08.001DOI Listing
March 2005