Publications by authors named "Stephen Mark"

32 Publications

Exploring PI3Kδ Molecular Pathways in Stable COPD and Following an Acute Exacerbation, Two Randomized Controlled Trials.

Int J Chron Obstruct Pulmon Dis 2021 3;16:1621-1636. Epub 2021 Jun 3.

Refractory Respiratory Inflammation Discovery Performance Unit, GlaxoSmithKline, Stevenage, UK.

Background: Inhibition of phosphoinositide 3-kinase δ (PI3Kδ) exerts corrective effects on the dysregulated migration characteristics of neutrophils isolated from patients with chronic obstructive pulmonary disease (COPD).

Objective: To develop novel, induced sputum endpoints to demonstrate changes in neutrophil phenotype in the lung by administering nemiralisib, a potent and selective inhaled PI3Kδ inhibitor, to patients with stable COPD or patients with acute exacerbation (AE) of COPD.

Methods: In two randomized, double-blind, placebo-controlled clinical trials patients with A) stable COPD (N=28, randomized 3:1) or B) AECOPD (N=44, randomized 1:1) received treatment with inhaled nemiralisib (1mg). Endpoints included induced sputum at various time points before and during treatment for the measurement of transcriptomics (primary endpoint), inflammatory mediators, functional respiratory imaging (FRI), and spirometry.

Results: In stable COPD patients, the use of nemiralisib was associated with alterations in sputum neutrophil transcriptomics suggestive of an improvement in migration phenotype; however, the same nemiralisib-evoked effects were not observed in AECOPD. Inhibition of sputum inflammatory mediators was also observed in stable but not AECOPD patients. In contrast, a placebo-corrected improvement in forced expiratory volume in 1 sec of 136 mL (95% Credible Intervals -46, 315mL) with a probability that the true treatment ratio was >0% (Pr(θ>0)) of 93% was observed in AECOPD. However, FRI endpoints remained unchanged.

Conclusion: We provide evidence for nemiralisib-evoked changes in neutrophil migration phenotype in stable COPD but not AECOPD, despite improving lung function in the latter group. We conclude that induced sputum can be used for measuring evidence of alteration of neutrophil phenotype in stable patients, and our study provides a data set of the sputum transcriptomic changes during recovery from AECOPD.
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http://dx.doi.org/10.2147/COPD.S309303DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8184158PMC
June 2021

Differences in treatment choices for localised prostate cancer diagnosed in private and public health services.

Med J Aust 2021 06 11;214(10):485-485.e1. Epub 2021 May 11.

University of Auckland, Auckland, New Zealand.

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http://dx.doi.org/10.5694/mja2.51081DOI Listing
June 2021

Healing or harming: the prostate cancer dichotomy.

N Z Med J 2020 10 9;133(1523):12-15. Epub 2020 Oct 9.

Consultant Urologist, Christchurch Hospital, Christchurch.

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October 2020

Good clinical practice can and must include comparative effectiveness research.

BJU Int 2018 11 13;122 Suppl 5:7-8. Epub 2018 Nov 13.

University of Otago, Christchurch, New Zealand.

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http://dx.doi.org/10.1111/bju.14590DOI Listing
November 2018

Quality Indicators for Global Benchmarking of Localized Prostate Cancer Management.

J Urol 2018 08 1;200(2):319-326. Epub 2018 Mar 1.

Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia. Electronic address:

Purpose: We sought to develop a core set of clinical indicators to enable international benchmarking of localized prostate cancer management using data available in the TrueNTH Global Registry.

Materials And Methods: An international expert panel completed an online survey and participated in a face-to-face meeting. Participants included 3 urologists, 3 radiation oncologists, 2 psychologists, 1 medical oncologist, 1 nurse and 1 epidemiologist with prostate cancer expertise from a total of 7 countries. Current guidelines on prostate cancer treatment and potential quality indicators were identified from a literature review. These potential indicators were refined and developed through a modified Delphi process during which each panelist independently and repeatedly rated each indicator based on importance (satisfying the indicator demonstrated a provision of high quality care) and feasibility (the likelihood that data used to construct the indicator could be collected at a population level). The main outcome measure was items with panel agreement indicated by a disagreement index less 1, median importance 8.5 or greater and median feasibility 9 or greater.

Results: The expert panel endorsed 33 indicators. Seven of these 33 prostate cancer quality indicators assessed care relating to diagnosis, 7 assessed primary treatment, 1 assessed salvage treatment and 18 assessed health outcomes.

Conclusions: We developed a set of quality indicators to measure prostate cancer care using numerous international evidence-based clinical guidelines. These indicators will be pilot tested in the TrueNTH Global Registry. Reports comparing indicator performance will subsequently be distributed to groups at participating sites with the purpose of improving the consistency and quality of prostate cancer management on a global basis.
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http://dx.doi.org/10.1016/j.juro.2018.02.071DOI Listing
August 2018

Solid, 3-mirror Fabry-Perot etalon.

Appl Opt 2017 Apr;56(10):2636-2640

We present modeling and performance of a solid, fused silica, 3-mirror Fabry-Perot-type etalon. 3-mirror etalons have been known for decades to have superior theoretical performance but for the first time we demonstrate an etalon with sufficient quality to realize the benefits of the more complex design. 3-mirror etalons have better passband shape and higher contrast ratio enabling significantly improved wavelength separation. We show the optical cavity design and construction of the new etalon and show >95% peak transmission, improved passband shape and 20 dB better out-of-band rejection than a similar 2-mirror etalon.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5831188PMC
http://dx.doi.org/10.1364/AO.56.002636DOI Listing
April 2017

Assessment of Potential Live Kidney Donors and Computed Tomographic Renal Angiograms at Christchurch Hospital.

Adv Urol 2016 10;2016:4924320. Epub 2016 Mar 10.

Christchurch Hospital, Private Bag 4710, Christchurch 8140, New Zealand.

Aims. To examine the outcome of potential live kidney donors (PLKD) assessment program at Christchurch Hospital and, also, to review findings of Computed Tomographic (CT) renal angiograms that led to exclusion in the surgical assessment. Methods. Clinical data was obtained from the database of kidney transplants, Proton. Radiological investigations were reviewed using the hospital database, Éclair. The transplant coordinator was interviewed to clarify information about PLKD who did not proceed to surgery, and a consultant radiologist was interviewed to explain unfavorable findings on CT renal angiograms. Results. 162 PLKD were identified during the period January 04-June 08. Of those, 65 (40%) proceeded to have nephrectomy, 15 were accepted and planned to proceed to surgery, 13 were awaiting further assessment, and 69 (42.5%) did not proceed to nephrectomy. Of the 162 PLKD, 142 (88%) were directed donors. The proportion of altruistic PLKD who opted out was significantly higher than that of directed PLKD (45% versus 7%, P = 0.00004). Conclusions. This audit demonstrated a positive experience of live kidney donation at Christchurch Hospital. CT renal angiogram can potentially detect incidental or controversial pathologies in the kidney and the surrounding structures. Altruistic donation remains controversial with higher rates of opting out.
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http://dx.doi.org/10.1155/2016/4924320DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4806264PMC
April 2016

Development of Indicators to Assess Quality of Care for Prostate Cancer.

Eur Urol Focus 2018 01 20;4(1):57-63. Epub 2016 Feb 20.

Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia. Electronic address:

Background: The development, monitoring, and reporting of indicator measures that describe standard of care provide the gold standard for assessing quality of care and patient outcomes. Although indicator measures have been reported, little evidence of their use in measuring and benchmarking performance is available. A standard set, defining numerator, denominator, and risk adjustments, will enable global benchmarking of quality of care.

Objective: To develop a set of indicators to enable assessment and reporting of quality of care for men with localised prostate cancer (PCa).

Design, Setting, And Participants: Candidate indicators were identified from the literature. An international panel was invited to participate in a modified Delphi process. Teleconferences were held before and after each voting round to provide instruction and to review results.

Outcome Measurements And Statistical Analysis: Panellists were asked to rate each proposed indicator on a Likert scale of 1-9 in a two-round iterative process. Calculations required to report on the endorsed indicators were evaluated and modified to reflect the data capture of the Prostate Cancer Outcomes Registry-Australia and New Zealand (PCOR-ANZ).

Results And Limitations: A total of 97 candidate indicators were identified, of which 12 were endorsed. The set includes indicators covering pre-, intra-, and post-treatment of PCa care, within the limits of the data captured by PCOR-ANZ.

Conclusions: The 12 endorsed quality measures enable international benchmarking on the quality of care of men with localised PCa. Reporting on these indicators enhances safety and efficacy of treatment, reduces variation in care, and can improve patient outcomes.

Patient Summary: PCa has the highest incidence of all cancers in men. Early diagnosis and relatively high survival rates mean issues of quality of care and best possible health outcomes for patients are important. This paper identifies 12 important measurable quality indicators in PCa care.
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http://dx.doi.org/10.1016/j.euf.2016.01.016DOI Listing
January 2018

Lateral-transfer recirculating etalon spectrometer.

Opt Express 2015 Nov;23(23):30020-7

We describe a Fabry-Perot etalon spectrometer with a novel light recirculation scheme to generate simultaneous parallel wavelength channels with no moving parts. This design uses very simple optics to recirculate light reflected from near normal incidence from the etalon at successively higher angles of incidence. The spectrometer has the full resolution of a Fabry-Perot with significantly improved photon efficiency in a compact, simple design with no moving parts. We present results from a conceptual prototype and a corresponding model.
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http://dx.doi.org/10.1364/OE.23.030020DOI Listing
November 2015

Active surveillance guidance for New Zealand men with low-risk prostate cancer.

N Z Med J 2015 Aug 21;128(1420):13-5. Epub 2015 Aug 21.

Department of Surgery, University of Otago, PO Box 7343, Wellington, New Zealand.

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August 2015

Once-daily dosing of levocabastine has comparable efficacy to twice-daily dosing in the treatment of allergic rhinitis assessed in an allergen challenge chamber.

Int J Clin Pharmacol Ther 2015 Oct;53(10):811-8

Objectives: To test the hypothesis that intranasal levocabastine (LEVO) may provide benefits as a oncedaily treatment in allergic rhinitis (AR), this non-inferiority study compared the effect at steady state of once- and twice-daily dosing with LEVO on allergen-induced nasal symptoms in AR patients.

Methods: This was a randomized, double-blind, three-way cross over study evaluating the effects of repeat doses of LEVO 200 µg once-daily, LEVO 200 µg twice-daily (total dose 400 µg) and placebo, all via intranasal spray, in 78 AR patients. The primary endpoint was weighted mean total nasal symptom score (TNSS) during a 4-hour allergen exposure in the Environmental Exposure Chamber measured at trough pharmacokinetic levels either 12 (LEVO twice-daily) or 24 (LEVO once-daily) hours post-dose.

Results: After 7 days dosing, the difference in weighted mean TNSS (0-4 hours) following LEVO once-daily versus twice-daily was 0.23 units (95% CI -0.36, 0.82), demonstrating noninferiority between the two LEVO dosing regimens by meeting the pre-specified criterion of an upper limit of 95% CI<1.0. Both dosing regimens of LEVO resulted in a statistically significant reduction in mean TNSS compared with placebo (adjusted mean difference from placebo: LEVO once-daily: -1.12 (95% CI -1.71, -0.53); LEVO twice-daily: -1.35 (-1.94, -0.76)), meeting the pre-specified criterion for superiority (upper limit of 95% CI<0). All treatments were well-tolerated.

Conclusions: The results of this study support the hypothesis that at steady state LEVO 200 µg taken once-daily provides similar benefit to LEVO 200 µg dosed twice-daily.
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http://dx.doi.org/10.5414/CP202389DOI Listing
October 2015

Clinical safety and effectiveness of collagenase clostridium histolyticum injection in patients with Peyronie's disease: a phase 3 open-label study.

J Sex Med 2015 Jan 12;12(1):248-58. Epub 2014 Nov 12.

Department of Urology, Rush University Medical Center, Chicago, IL, USA.

Introduction: Collagenase clostridium histolyticum (CCH; Xiaflex, Auxilium Pharmaceuticals, Inc., Chesterbrook, PA, USA) is a Food and Drug Administration-approved, intralesional treatment for Peyronie's disease (PD).

Aim: The aim of this study was to assess the safety and effectiveness of CCH in the treatment of PD.

Methods: This phase 3, open-label study enrolled subjects who were CCH-naïve, were enrolled in a previous pharmacokinetic study, or had received placebo in an earlier phase 2 CCH study. Each treatment cycle included two intralesional injections of CCH 0.58 mg, approximately 24-72 hours apart, and plaque modeling 24-72 hours after the second injection of each cycle. The treatment cycle was repeated after 6 weeks for ≤4 treatment cycles.

Main Outcome Measures: The co-primary end points were the mean percent change in penile curvature deformity and the mean improvement in PD bother score (range 0-16) from baseline to week 36.

Results: Of the 347 subjects treated with ≥1 injection, 238 had both a penile curvature measurement and a Peyronie's Disease Questionnaire response at baseline and ≥1 subsequent time point. Mean baseline penile curvature deformity was 53.0° and mean PD symptom bother was 7.3. Statistically significant mean improvements from baseline to week 36 were observed in both penile curvature deformity (34.4% [95% confidence interval {CI}, 31.2%, 37.6%]) and PD symptom bother score (3.3 [95% CI, 2.8, 3.7]). Most adverse events (AEs) were mild or moderate in severity and local to the penis. There were three serious treatment-related AEs, two penile hematomas and one corporal rupture; all resolved with treatment.

Conclusions: Potentially clinically meaningful and statistically significant improvements in penile curvature deformity and PD symptom bother scores were observed with intralesional injection of CCH compared with baseline in men with PD. CCH was generally well tolerated, with AEs primarily transient and local to injection site. In conjunction with previous studies, the results of this open-label study support the use of CCH in the treatment of PD.
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http://dx.doi.org/10.1111/jsm.12731DOI Listing
January 2015

Improving outcomes for New Zealand men with prostate cancer.

N Z Med J 2014 Feb 14;127(1389):13-6. Epub 2014 Feb 14.

Department of Surgery, University of Otago, PO Box 7343, Wellington, New Zealand.

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February 2014

Pulsed airborne lidar measurements of atmospheric optical depth using the Oxygen A-band at 765 nm.

Appl Opt 2013 Sep;52(25):6369-82

We report on an airborne demonstration of atmospheric oxygen optical depth measurements with an IPDA lidar using a fiber-based laser system and a photon counting detector. Accurate knowledge of atmospheric temperature and pressure is required for NASA's Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission, and climate modeling studies. The lidar uses a doubled erbium-doped fiber amplifier and single photon-counting detector to measure oxygen absorption at 765 nm. Our results show good agreement between the experimentally derived differential optical depth measurements with the theoretical predictions for aircraft altitudes from 3 to 13 km.
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http://dx.doi.org/10.1364/AO.52.006369DOI Listing
September 2013

Dolutegravir does not affect methadone pharmacokinetics in opioid-dependent, HIV-seronegative subjects.

Drug Alcohol Depend 2013 Dec 26;133(2):781-4. Epub 2013 Aug 26.

GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, USA.

Background: Dolutegravir (DTG) is an investigational integrase inhibitor for treatment of HIV infection. As intravenous drug use is a common risk factor for HIV, this study evaluated the effect of DTG on the pharmacokinetics (PK) of methadone.

Methods: This was an open-label, 2-period study in adult, opioid-dependent, HIV-seronegative subjects. Subjects received their current individual methadone doses once daily for 3 days (Period 1) followed by DTG 50mg twice daily (BID) for 5 days while continuing their stable methadone therapy (Period 2). Serial PK samples for R- and S-methadone were collected after each Period. Pharmacodynamic (PD) measures and safety assessments were obtained throughout the study. Non-compartmental PK analysis was performed, and geometric least-squares mean ratios and 90% confidence intervals were generated.

Results: Plasma exposures of total, R-, and S-methadone were not affected by co-administration of DTG. Mean ratios for AUC were 0.98, 0.95, and 1.01 for total, R-, and S-methadone, respectively, alone compared with in combination with DTG. No statistically significant differences were noted between the 2 treatment periods in methadone PD measures. The combination of DTG and methadone was well tolerated. No deaths, serious adverse events, or grade 3/4 adverse events occurred. No clinically significant changes in laboratory values, vital signs, or electrocardiograms were observed.

Conclusion: Co-administration of methadone with repeat doses of DTG 50mg BID had no effect on total, R-, and S-methadone PK or on methadone-induced PD markers. No dose adjustment in methadone is required when given in combination with DTG.
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http://dx.doi.org/10.1016/j.drugalcdep.2013.08.009DOI Listing
December 2013

Transurethral prostate resection for urinary retention: does age affect outcome?

ANZ J Surg 2013 Apr 27;83(4):243-5. Epub 2012 Nov 27.

Department of Urology, Christchurch Hospital, Christchurch, New Zealand.

Background: Patients presenting in urinary retention secondary to prostatic obstruction are offered transurethral resection of the prostate (TURP) to free them from long-term catheterization. Short-term success is well understood, but there is scarce data about effect of age on outcome, quality of life and catheter-free rates.

Methods: One hundred consecutive patients who presented in urinary retention and underwent TURP were identified. Patients were followed up for 3 years to establish the rate of catheter dependence, incontinence, pad usage and quality of life using the International Prostate Symptom Score.

Results: Data were obtained from 95 patients with mean age of 75.6 years and mean follow-up of 704 days. A total of 14 had died and 23 had prostate cancer. Eighty-seven per cent was passing urine and 13% was catheter dependent. Mean age of catheter-dependent patients was 84.9 years compared with 74.3 years in catheter-free men (P < 0.0001). Twenty-four per cent of patients 80 years and older were catheter dependent (P = 0.0039), 22% with prostate cancer were catheter dependent (P = 0.15). Fifty per cent of those who had died were catheter dependent (P = 0.0002). Thirty-one per cent of patients reported leakage of urine but only 5% reported leakage requiring pad use. Overall, the mean quality of life score was 1.08.

Conclusion: Outcome after TURP for urinary retention is satisfactory. Advanced age is associated with higher long-term failure requiring catheterization, although it is still recommended in the elderly where an anaesthetic is safe. A high proportion of patients report urine leakage but the majority of this is clinically insignificant. Overall, patients report good quality of life.
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http://dx.doi.org/10.1111/ans.12014DOI Listing
April 2013

The reasons for cancellation of urological surgery: a retrospective analysis.

N Z Med J 2012 Aug 10;125(1359):17-22. Epub 2012 Aug 10.

Department of Urology, Private Bag 4710, Christchurch Hospital, Christchurch, New Zealand.

Aim: To identify preventable reasons for surgery being cancelled and to identify steps which may minimise their occurrence.

Method: All cancellations of surgery in the Department of Urology, Christchurch Hospital between the dates 31 March 2008 and 11 March 2011 were retrospectively identified from minutes of the Department's weekly audit meetings. These were then assigned reasons for cancellation according to those devised by the Veterans Health Administration system1.

Results: From 4303 total operations performed, 180 cancellations occurred over the almost-3-year study period. This equated to a cancellation rate of 4.2%.34 cases (18.9%) were due to patient factors, 66 cases (36.7%) due to work-up factors, 70 (38.9%) due to facility factors, 9 cases (5%) due to surgeon factors.

Conclusion: A significant proportion of the 4.2% patients cancelled were preventable. Optimisation of the preadmission process as well as elucidation of the reasons for theatre over-runs were identified as key to reducing the rate of cancellation. Measurement of cancellations in the audit meeting contributes to a low cancellation rate.
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August 2012

Male flexible cystoscopy: does waiting after insertion of topical anaesthetic lubricant improve patient comfort?

BJU Int 2011 Nov;108 Suppl 2:42-4

Department of Urology, Christchurch Hospital, Christchurch, New Zealand.

Unlabelled: What's known on the subject? and What does the study add? Flexible cystoscopy is commonly performed. Several studies show that topical anaesthetic lubricant reduces patient discomfort, particularly with long lubricant retention times (15-25 min). No studies have specifically addressed whether a short, clinically manageable retention time provides any benefit over immediate cystoscopy. Our study demonstrates that delay by a 3-min interval provides no benefit to patients and a more expedient approach can be justified without compromising patient comfort. LAY-TERM SUMMARY: This prospective comparative trial randomizes 50 men to undergo flexible cystoscopy with insertion of local anaesthetic lubricant either immediately prior to cystoscope insertion or after a 3-min interval. Patients then report discomfort on a visual analogue scale. We show that there is no benefit to delay and therefore a more expedient approach can be justified.

Objective: • To determine whether a short, clinically manageable time delay between lubrication with topical local anaesthetic and insertion of the flexible cystoscope, vs immediate insertion, reduces discomfort in male patients.

Patients And Methods: • This was a prospective comparative trial. • Male patients undergoing simple flexible cystoscopy were randomized to undergo cystoscope insertion either immediately after lubrication with topical lignocaine gel or after a 3-min delay. • Patient-reported pain of the procedure was recorded on a visual analogue scale and data were statistically analysed.

Results: • Fifty male patients were randomized to cystoscope insertion either immediately following lubrication or after a 3-min delay. • Mean pain score in the immediate insertion group was 11.94 mm (95% confidence interval [CI] 7.53-16.36) compared with 10.52 mm (95% CI 6.24-14.80) in the 3-min delay group. • The mean difference between the two groups was 1.42 mm (95% CI -4.57 to 7.41, P= 0.64).

Conclusion: • Findings show that patient comfort is similar between the two groups and therefore there is no benefit in delaying insertion by a 3-min interval. • Flexible cystoscopy is a well tolerated outpatient procedure.
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http://dx.doi.org/10.1111/j.1464-410X.2011.10696.xDOI Listing
November 2011

Combined traumatic occiput-C1 and C1-C2 dissociation: 2 case reports.

Am J Orthop (Belle Mead NJ) 2010 Aug;39(8):392-5

Department of Orthopaedics, Stony Brook University Medical Center, NY 11794, USA.

Occiput-C1 and C1-C2 dissociations and dislocations have been well documented in the literature. However, after thorough review of the literature, we found very little in the literature regarding combined occiput-C1 and C1-C2 dissociations in adults who survived. We present 2 case reports describing the clinical presentation, initial management, operative treatment, and postoperative course of 2 patients who sustained traumatic combined occiput-C1 and C1-C2 dissociations. After initial stabilization, both patients underwent open reduction and posterior occipital-cervical fusion with segmental fixation. At recent follow-up, both patients maintain good sagittal alignment without loss of reduction, and they have radiographic progression to fusion, minimal pain, and improved neurologic function. Combined occiput-C1 and C1-C2 dissociations are rare but serious injuries. Incomplete dissociations may not be evident on initial radiographs. Computed tomography or magnetic resonance imaging is recommended for formal diagnosis. A traumatic dural tear may be present. We recommend open reduction and posterior occipital-cervical fusion with segmental fixation for these patients.
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August 2010

Kilowatt-level stimulated-Brillouin-scattering-threshold monolithic transform-limited 100 ns pulsed fiber laser at 1530 nm.

Opt Lett 2010 Jul;35(14):2418-20

NP Photonics, Incorporated, 9030 South Rita Road, Tucson, Arizona 85747, USA.

We demonstrate a high-stimulated-Brillouin-scattering-threshold monolithic pulsed fiber laser in a master oscillator power amplifier configuration that can operate over the C band. In the power amplifier stage, we used a newly developed single-mode, polarization maintaining, and highly Er/Yb codoped phosphate fiber with a core diameter of 25 microm. A single-frequency actively Q-switched fiber laser was used to generate pulses in the hundreds of nanoseconds at 1530 nm. We have achieved peak power of 1.2 kW for 105 ns pulses at a repetition rate of 8 kHz, corresponding to a pulse energy of 0.126 mJ, with transform-limited linewidth and diffraction-limited beam quality.
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http://dx.doi.org/10.1364/OL.35.002418DOI Listing
July 2010

Traumatic thoracic spondyloptosis without neurologic deficit, and treatment with in situ fusion.

Am J Orthop (Belle Mead NJ) 2009 Oct;38(10):E162-5

Department of Orthopaedic Surgery, Stony Brook University Medical Center, Stony Book, NY 11794, USA.

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October 2009

Comparison of kidney-ureter-bladder abdominal radiography and computed tomography scout films for identifying renal calculi.

BJU Int 2009 Sep;104(5):670-3

Department of Urology, Christchurch Public Hospital, Christchurch, New Zealand.

Objective: To assess the sensitivity of computed tomography (CT) scout topograms and kidney-ureter-bladder abdominal radiography (KUB) in detecting urinary tract stones.

Patients And Methods: We assessed films taken on presentation for 163 consecutive patients referred to our service for stone follow-up. Only those with both CT and KUB imaging on the same day were studied further. Two urology registrars examined the films independently. Location, size and length of stone were recorded. Where there was discordance, the films were examined by an independent radiologist.

Results: In all, 108 of 163 patients had both CT and KUB imaging on the same day. Stones were identified in 63% (68/108) of patients with KUB, with a mean length of 4.93 mm. There were 40/108 radiolucent stones subsequently measured on CT, with a mean length of 4.90 mm. Stones were seen on 47% (51/108) of the CT scouts, with a mean length of 5.22 mm. Importantly, all stones visible on CT scout were also visible on KUB. There was no correlation between stone location and visibility on KUB or CT scout films.

Conclusion: KUB could be used for follow-up in 63% of cases. All stones seen on CT scout were also visible on KUB. Scout detected 75% of stones visible on KUB. We suggest CT scout film should be reported before proceeding to KUB. If the stone is visible on CT scout film, then the decision to use KUB for follow-up can be made. This minimizes radiation exposure and other costs.
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http://dx.doi.org/10.1111/j.1464-410X.2009.08542.xDOI Listing
September 2009

Prognostic factors in malignant ureteric obstruction.

BJU Int 2009 Oct 26;104(7):938-41. Epub 2009 Mar 26.

Urology, Christchurch Hospital, Christchurch, New Zealand.

Objective: To validate a model to stratify patients with obstructive nephropathy due to malignant ureteric obstruction, associated with a poor prognosis, into different prognostic groups, as a recent report identified low serum albumin, degree of hydronephrosis and number of events related to metastatic disease as prognostic indicators before palliative decompression.

Patients And Methods: We retrospectively review the charts to identify all patients who had a nephrostomy tube inserted for malignant ureteric obstruction. Laboratory and clinical factors that might influence prognosis were reviewed to attempt to externally validate the previously identified factors and model for risk stratification.

Results: The median (range) age of the 49 patients identified was 71 (36-91) years, and the median survival was 174 (14-602) days. Tumours were of urological origin in 66% of patients. Patients with prostate cancer had nephrostomy tubes indwelling for a mean of 279 days, vs 190 days (P = 0.07) for patients with tumours not of prostatic origin. A serum albumin level of >30 g/L (P ≤ 0.001), serum sodium <135 mmol/L (P = 0.019) and three or more events related to dissemination of cancer (P = 0.04) were factors associated with a significantly shorter mean survival. Complications related to the nephrostomy tube were experienced by 39% of patients. The model proved useful in stratifying these patients into different risk groups (P = 0.002).

Conclusion: Consistent with a previous report we showed that a low serum albumin level and events related to metastatic disease were indicative of a poor prognosis. We also found that a low serum sodium level might be associated with a worse prognosis. We externally validated a model for stratifying patients into different prognostic groups. Palliative decompression is associated with significant morbidity.
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http://dx.doi.org/10.1111/j.1464-410X.2009.08492.xDOI Listing
October 2009

Results and morbidity in a consecutive series of patients undergoing spinal fusion with iliac screws for neuromuscular scoliosis.

Orthopedics 2008 Dec;31(12)

Department of Orthopedic Surgery, Stony Brook University Hospital, Stony Brook, NY 11793, USA.

We performed a retrospective review study to evaluate the safety and efficacy of iliac screws as a method of pelvic fixation in neuromuscular spinal deformity. All patients with the diagnosis of neuromuscular scoliosis operatively managed with iliac screws undergoing posterior spinal fusion were retrospectively identified over a 32-month period, from December 2002 to August 2005. Evaluation was done for correction of deformity, progression, instrumentation failure, and complications. Progression was defined as an increase in Cobb angle >5 degrees . Of the 14 eligible patients, 12 (86%) had adequate follow-up, with an average final follow-up of 19.5 months (range, 12-39 months). Average patient age at surgery was 15 years. Average number of instrumented levels was 16, with the most common levels being from the second thoracic vertebrae to the sacrum (11/12). A significant correction of deformity from a mean preoperative 66.5 to a mean postoperative 22.8 was achieved. Average postoperative L5-S1 angle was 31 degrees and L1-S1 angle was 61 degrees. At final follow-up, the average L5-S1 angle was 26 degrees and L1-S1 angle was 59 degrees < neither a statistically significant progression (P=.70 and P=.30, respectively). The maximum measured progression was 16 degrees for L5-S1 and 12 degrees for L1-S1. There were no incidences of rod breakage, and there was 1 iliac screw offset connector dislodgement from the rod, which did not require revision. There were no intraoperative complications. There were 3 postoperative wound infections, which required irrigation and debridement and eventually resulted in fusion. In conclusion, this is one of the largest reports of iliac screw use in the correction of neuromuscular scoliosis. In our series we were able to correct the deformity and maintain the lumbar lordosis without progression or failure with a relatively low complication rate.
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http://dx.doi.org/10.3928/01477447-20081201-08DOI Listing
December 2008

Cauda equina syndrome: a comprehensive review.

Am J Orthop (Belle Mead NJ) 2008 Nov;37(11):556-62

Department of Orthopaedic Surgery, Stony Brook University Medical Center, Stony Brook, New York, USA.

Cauda equina syndrome (CES) is a rare syndrome that has been described as a complex of symptoms and signs--low back pain, unilateral or bilateral sciatica, motor weakness of lower extremities, sensory disturbance in saddle area, and loss of visceral function--resulting from compression of the cauda equina. CES occurs in approximately 2% of cases of herniated lumbar discs and is one of the few spinal surgical emergencies. In this article, we review information that is critical in understanding, diagnosing, and treating CES.
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November 2008

New Zealand medical school teaching and surgical training.

Authors:
Stephen D Mark

N Z Med J 2008 May 9;121(1273):11-2. Epub 2008 May 9.

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May 2008

The successful short-term treatment of flexion-distraction injuries of the thoracic spine using posterior-only pedicle screw instrumentation.

J Spinal Disord Tech 2008 May;21(3):192-8

Department of Orthopaedics, Stony Brook University Medical Center, Spine and Scoliosis Center, T-18 Health Sciences Center, Stony Brook, NY 11794-8181, USA.

Study Design: In this retrospective study, the results of treating unstable flexion-distraction injuries (FDI) of the thoracic spine with posterior-only thoracic pedicle screw (P/TPS) instrumentation were investigated.

Objective: The objective was to determine the ability of P/TPS to correct and maintain the focal kyphosis of the injured spine. Clinical outcome and complications of the surgical procedure were also a focus of the study.

Summary Of Background Data: The treatment of FDI of the thoracic spine remains controversial. There continues to be difficulty in maintaining the corrected kyphosis angle regardless of the surgical approach used.

Methods: Eighteen patients with FDI of thoracic spine who underwent P/TPS were identified. The initial and corrected focal kyphosis was evaluated radiographically. Failure of treatment was defined as a >5-degree progression of corrected kyphosis from initial to latest follow-up. Clinical evaluation included complication rate, Injury Severity Score, and Frankel grade.

Results: Of the 18 eligible patients, 15 (83%) had adequate follow-up for evaluation. The mean length of follow-up care was 16.1 months. The average Injury Severity Score was 23. The average number of instrumented levels was 6.8. The focal kyphosis of the injury was reduced from a mean of 19.60 to 5.73 degrees (P<0.001), with an average progression of only 2.27 degrees (P=0.128) at final follow-up. Complications were limited to wound infections and occurred in 2 study participants. Neurologic status returned to normal in all patients with incomplete cord injuries.

Conclusions: FDI of the thoracic spine may be amendable to a uniform surgical approach with P/TPS. This procedure carried a relatively low complication rate and allowed for reduction and restoration of the posterior tension band with a biomechanically rigid construct.
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http://dx.doi.org/10.1097/BSD.0b013e318074ddcdDOI Listing
May 2008

Narrowband, tunable, frequency-doubled, erbium-doped fiber-amplifed transmitter.

Opt Lett 2007 Aug;32(15):2073-5

NASA's Goddard Space Flight Center, Laser and Electro-Optics Branch, Greenbelt, Maryland 20771, USA.

We report on the development of a fiber-based laser transmitter designed for active remote sensing spectroscopy. The transmitter uses a master oscillator power amplifier (MOPA) configuration with a distributed feedback diode-laser master oscillator and an erbium-doped fiber amplifier. The output from the MOPA is frequency-doubled with a periodically poled potassium titanium oxide phosphate crystal. With 35 W of single-frequency peak optical pump power, 8 W of frequency-doubled peak power was achieved. The utility of this single-frequency, wavelength tunable, power scalable laser was then demonstrated in a spectroscopic measurement of diatomic oxygen A band.
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http://dx.doi.org/10.1364/ol.32.002073DOI Listing
August 2007

Biomechanical evaluation of surgical constructs for stabilization of cervical teardrop fractures.

Spine J 2006 Sep-Oct;6(5):514-23. Epub 2006 Jul 11.

Department of Biomedical Engineering, Stony Brook University, HSC T18-030, Stony Brook, NY 11794, USA.

Background Context: Cervical flexion teardrop fractures (CFTF) are highly unstable injuries, and the optimal internal fixation construct is not always clearly indicated.

Purpose: The purpose of the current study was to determine whether the type of fixation construct (anterior, posterior, or combined) or number of joint levels involved in fixation (one or two) affected the relative stability of a CFTF injury at C5-C6.

Study Design/setting: Human cadaveric cervical spine specimens were mechanically tested under displacement control in the intact state and after creation of CFTF at C5-C6 with stabilization using five different instrumentation constructs. Joint stiffness and intervertebral translation of the constructs were compared with the intact state and normalized (instrumented/intact) to assess relative differences across the five constructs.

Methods: Spine specimens were mechanically tested in the intact state during flexion, extension, lateral bending, and axial rotation. CFTF was created at C5-C6 by creating an osteotomy at C5 and transecting the posterior ligaments and intervertebral disc. Specimens were tested with anterior, posterior, and combined single-level constructs (C5-C6). Then, a corpectomy was performed at C5, and specimens were retested with the two-level constructs (C4-C6; anterior and anterior-posterior). Joint stiffness and intervertebral translations were computed.

Results: All five fixation constructs resulted in joint stability that was as good as or better than that of the intact specimens. Relative stiffness of the constructs differed depending upon the motion type considered, though the two-level anterior-posterior construct typically provided the greatest stability. Intervertebral translation along the major axis was reduced the most for both of the combined instrumentation systems, although there were few changes in total intervertebral translation across the five constructs.

Conclusions: All five constructs restored stability comparable to that of the intact specimens. The significance of the relative differences in constructs for the in vivo spine is unclear and warrants further clinical investigation.
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http://dx.doi.org/10.1016/j.spinee.2005.12.001DOI Listing
January 2007
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