Michelle J Semins

University of Pittsburgh, Pittsburgh, Pennsylvania, United States

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Publications (38)64.28 Total impact

  • Michelle J Semins, Brian R Matlaga
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    ABSTRACT: Kidney stones affect 10% of people at some point in their lives and, for some unfortunate women, this happens during pregnancy. Pregnancy is a complex state and both physiological and mechanical changes alter risk factors for kidney stone formation. When a pregnant woman develops acute nephrolithiasis, the situation is more complicated than in nonpregnant women. Imaging limitations and treatment restrictions mean that special diagnostic and management algorithms are needed upon presentation. Ultrasonography remains the gold-standard first-line diagnostic imaging modality for kidney stones during pregnancy but several second-line alternatives exist. Acute renal colic during pregnancy is associated with risks to both mother and fetus. As such, these patients need to be handled with special attention. First-line management is generally conservative (trial of passage and pain management) and is associated with a high rate of stone passage. Presentation of obstructive nephrolithiasis with associated infection represents a unique and serious clinical situation requiring immediate drainage. If infection is not present and conservative management fails, ureteroscopy can be offered if clinically appropriate, but, in some circumstances, temporary drainage with ureteral stent or nephrostomy tube might be indicated. Shockwave lithotripsy and percutaneous nephrolithotomy are contraindicated during pregnancy.
    Nature Reviews Urology 02/2014; · 4.79 Impact Factor
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    ABSTRACT: Introduction Flexible ureteroscopy (URS) is rapidly becoming a first-line therapy for many with renal and ureteral stones. However, the present understanding of treatment outcomes for patients with isolated proximal ureteral stones is limited. Therefore, we performed a prospective, multi-institutional study of ureteroscopic management of proximal ureteral stones < 2 cm in order to better define clinical outcomes associated with this approach. Methods Adult patients with proximal ureteral calculi < 2 cm were prospectively identified. Patients with concomitant ipsilateral renal calculi or prior ureteral stenting were excluded. Flexible URS, Holmium laser lithotripsy, and ureteral stent placement was performed. Ureteral access sheath use, laser settings, and other details of peri- and postoperative management were based on individual surgeon preference. Stone clearance was determined by renal ultrasound and KUB results at 4–6 weeks postoperatively. Results Of 71 patients, 44 (62%) were male and 27 (38%) were female. Mean age was 48.2 years. ASA score was 1 in 12 (16%), 2 in 41 (58%), 3 in 16 (23%), and 4 in 2 (3%). Mean BMI was 31.8 kg/m2. Mean stone size was 7.4mm (5-15). Mean surgical time was 60.3 minutes (15-148). Intraoperative complications occurred in 2 (2.8%) including mild ureteral trauma. Postoperative complications occurred in 6 (8.7%) including UTI (3), urinary retention (2), and flash pulmonary edema (1). The stone-free rate was 95%; for stones <1cm, the stone-free rate was 100%. Conclusions Flexible URS is associated with excellent clinical outcomes and acceptable morbidity when applied to patients with proximal ureteral stones < 2 cm.
    The Journal of Urology. 01/2014;
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    Julie M Riley, Anne Griffin Dudley, Michelle Jo Semins
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    ABSTRACT: Introduction: The incidence of nephrolithiasis has consistently been increasing over recent decades. This has been attributed to diet, obesity, environmental temperature changes, and co-morbid diseases such as diabetes. Incidence change has not been studied in the pregnant population. Herein, we report our experience with stone diagnosis in this unique patient population over the past 2 decades. Methods: Hospital data from a tertiary women's hospital was examined for ICD-9 codes for pregnancy (640-648, V22.0, V22.1, V22.2) and urolithiasis (592.0, 592.1, 592.9) between 1991 and 2011. The change in incidence in nephrolithiasis, pregnancy and the combination of both was examined. Results: In the 21 year period studied, 876 pregnant patients were given a diagnosis of nephrolithiasis at our hospital. Over the same time, 204,034 pregnant patients and 3,262 stone patients were treated. Comparing patients seen from 1991-2000 to those seen from 2001-2011 revealed a significant increase in stone patients (78 vs. 226/year, p=0.004) but no change in pregnant patients (9467 vs. 9942/year, p=0.3) or pregnant patients with stones (36 vs. 47, p=0.1). Evaluating patients at 5-year intervals confirmed the expected increase in stone patients but no change in incidence of nephrolithiasis in pregnant patients was noted. Conclusion: There was no change in incidence of nephrolithiasis in pregnant patients over a 2-decade period. Further research is warranted to determine why the pregnant population does not have the expected increase in nephrolithiasis. Larger, multi-institutional studies are needed to validate our results.
    Journal of endourology / Endourological Society 10/2013; · 1.75 Impact Factor
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    ABSTRACT: To determine International Classification of Disease, 9th Revision, (ICD-9) coding patterns as a proxy for incidence and prevalence of urinary incontinence (UI) in a population of patients before and after a bariatric surgical procedure for the treatment of obesity. We evaluated claims from a national private insurer over a 5-year period (2002-2006) to identify female patients who underwent bariatric surgery and had 3 years of follow-up claims data. The cohort of patients who underwent bariatric surgery (treatment) was matched to a cohort of obese female patients who did not undergo bariatric surgery (control), who were followed from the start of their enrollment. UI was identified by ICD-9 coding. After bariatric surgery, 62.4% of patients (83/133) diagnosed with UI before their surgery no longer had a coding diagnosis of UI. In contrast, only 42.1% (56/133) of those in the nonbariatric surgery cohort lost their coding diagnosis of UI (P = .0009). Of those that did not have pre-existing UI, 6.2% (235/3765) of the bariatric surgery cohort gained a new coding diagnosis of UI vs 7.1% (269/3765) of the control group (P = .1169). Our final model suggested that age >45 years (P <.0001) and pre-existing UI (P <.0001) were significantly associated with post-index date UI. Interaction between bariatric surgical status and UI was also significant (P <.0001). Patients who undergo bariatric surgery are more likely to lose a previous diagnosis of UI than are obese patients not treated with bariatric surgery. This supports the fact that bariatric surgery may have other indirect benefits to the obese population.
    Urology 07/2013; · 2.42 Impact Factor
  • Michelle J Semins, Brian R Matlaga
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    ABSTRACT: Kidney stones are common and do not spare the pregnant population. Although a simple stone event is usually straightforward in the general population, it is complex during pregnancy. Acute nephrolithiasis is associated with a unique set of complications during pregnancy and, because of imaging limitations, diagnosis is challenging. Multidisciplinary care is the key in proper management decisions. The pathophysiology of kidney stone formation in the pregnant state is also unique. Herein, we discuss the complexity of kidney stones and pregnancy.
    Advances in chronic kidney disease 05/2013; 20(3):260-4. · 2.42 Impact Factor
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    ABSTRACT: With the introduction of a 3-T scanner, magnetic resonance urography (MRU) may be an alternative imaging modality for evaluation of acute renal colic. We performed a prospective study to compare the performance of computed tomography (CT) with half-Fourier single shot turbo spin-echo (HASTE) MRU in the evaluation of patients with suspected renal colic. Patients presenting to the emergency department with acute renal colic were eligible for inclusion. Following a standard CT stone evaluation, patients underwent a non-contrast HASTE MRU study with a 3-T scanner. The presence of perinephric fluid, hydronephrosis, ureteral obstruction, and calculus was assessed. A total of 22 patients completed the study. Twenty (91 %) were diagnosed with an upper tract stone by radiographic findings. MRU detected a discrete stone in 50 % of the patients with stones detected by CT. Perinephric fluid was noted in 12 MRUs, compared to 7 CTs. Using CT as the reference standard, the combination of stone or perinephric fluid and ureteral dilation gave MRU a sensitivity of 84 %, specificity of 100 %, and accuracy of 86 % (95 % CI 0.72-1.0). HASTE MRU with a 3-T MR scanner can reliably detect the presence of upper urinary tract obstruction. Although CT imaging remains the superior modality with which to detect calculi, MRU detects a greater number of secondary signs of upper tract obstruction. For situations in which the use of ionizing radiation is undesirable, MRU is a reasonable imaging alternative.
    Urolithiasis. 02/2013; 41(1):43-6.
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    Michelle Jo Semins, Brian R Matlaga
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    ABSTRACT: Kidney stones are very common and unfortunately do not spare the pregnant population. Anatomical and pathophysiological changes occur in the pregnant female that alter the risk for development of nephrolithiasis. Acute renal colic during pregnancy is associated with significant potential risks to both mother and fetus. Diagnosis is often challenging because good imaging options without radiation use are limited. Management of diagnosed nephrolithiasis is unique in the pregnant population and requires multi-disciplinary care. Herein, we review the metabolic alterations during pregnancy that may promote kidney stone formation, the complications associated with acute renal colic in the pregnant state, and our proposed diagnostic and management algorithms when dealing with this clinical scenario.
    International Journal of Women's Health 01/2013; 5:599-604.
  • Stacy Loeb, Michelle Jo Semins, Brian R Matlaga
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    ABSTRACT: To describe a novel method for fragment evacuation after percutaneous lithotripsy of neobladder calculi. The technique was developed using a Urovac bladder evacuator, which was attached to a standard 30F Amplatz working sheath. The attachment of the Urovac evacuator to the Amplatz sheath rapidly evacuated large quantities of stone material. Careful attention should be paid to maintaining low-pressure irrigation by ensuring the bladder is not overly full and the Urovac device is not vigorously manipulated, to minimize the likelihood of bladder injury. Percutaneous ultrasonic/hydraulic lithotripsy for large-volume neobladder calculi often results in a substantial burden of stone fragments that can be difficult to clear using standard techniques. Attaching a Urovac bladder evacuator to the 30F Amplatz sheath can simplify the management of this task.
    Urology 08/2012; 80(2):474-6. · 2.42 Impact Factor
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    ABSTRACT: To report our experience with magnetic resonance urography (MRU) in pregnant women suspected of having obstructing upper tract calculi. The diagnosis of an upper tract calculus in the pregnant woman can be challenging. Recent evidence suggests that MRU can be used to effectively evaluate renal colic. From 2008-2011, 9 pregnant women were referred for evaluation of suspected renal colic caused by an obstructing upper tract stone. All patients underwent MRU with a half Fourier single-shot turbo spin-echo (HASTE) protocol. Medical records and imaging studies were reviewed for demographic and clinical data as well as outcome measures. The mean age of the subjects was 25 years (range 20-34); average gestational age of the fetus was 23 weeks (range 9-36). In all cases, a renal ultrasound was the initial imaging study obtained, with nondiagnostic findings. HASTE MRU detected 4 ureteral stones and 4 cases of physiological hydronephrosis of pregnancy. In one case, interpretation of the MRU was limited as a result of patient motion. Of the patients with obstructing stones, 1 required endourologic management during her pregnancy and 3 were followed conservatively. No adverse events related to MRU occurred. HASTE MRU is an informative imaging study for pregnant women with suspected upper tract stone disease. Information gathered from this study augments that gained from alternative modalities, and aids in medical decision-making. The lack of ionizing radiation exposure, coupled with the capture of detailed anatomic imaging, makes HASTE MRU a particularly useful study in this setting.
    Urology 03/2012; 79(6):1252-5. · 2.42 Impact Factor
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    ABSTRACT: As surgical technology continues to advance, stone baskets are becoming increasingly miniaturized. We performed a study to define the effect of miniaturized stone baskets on ureteroscope irrigation flow and deflection. We compared the three smallest available stone baskets: Boston Scientific 1.3F OptiFlex, Cook 1.5F N-Circle, and Sacred Heart 1.5F Halo, measuring their effect on irrigant flow and deflection of three flexible ureteroscopes. All devices adversely affected irrigation flow and active deflection of all of the ureteroscopes (P<0.05). The 1.3F device, however, exhibited significantly less of an effect on both parameters. Irrigation flow was 28% greater with the 1.3F device than it was for the 1.5F devices. The device's effect on active deflection was 43% less with the 1.3F device than it was for the 1.5F devices. Any device placed through the working channel of a ureteroscope will have a deleterious effect on the ureteroscope's irrigant flow and active deflection. As the caliber of the device decreases, however, its effect on these parameters appears to be reduced. Our present data suggest that the 1.3F basket has significantly less of an effect on both the irrigant flow and deflection of a flexible ureteroscope than do the 1.5F devices.
    Journal of endourology / Endourological Society 03/2012; 26(3):275-7. · 1.75 Impact Factor
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    ABSTRACT: To perform a study to describe the way in which an increasingly obese body mass index (BMI) is associated with urinary tract infection (UTI). The association between UTI and obesity is not well characterized. In fact, previous investigations of this subject have yielded conflicting findings. UTI is increasingly being recognized as a preventable complication, and UTI rates are used to measure quality of surgical care. We evaluated claims over a 5-year period (2002-2006) in a national private claims database to identify patients diagnosed with UTI or pyelonephritis by ICD-9 coding. Descriptive analyses were performed and odds ratios were calculated. A total of 95,598 subjects were identified for evaluation. Gender distribution was 42.9% male and 57.1% female. In the overall study cohort, the diagnosis of a UTI or pyelonephritis occurred in 13% and 0.84%, respectively. Women were 4.2 times more likely to be diagnosed with a UTI (19.3% vs 4.6%), and 3.6 times more likely to be diagnosed with pyelonephritis (1.22% vs 0.34%), than were men. At all stratifications of obesity, the obese were significantly more likely to be diagnosed with a UTI or pyelonephritis than nonobese patients. Elevated BMI appears to be associated with an increased risk for UTI and pyelonephritis. Further study is needed to determine whether this association may be attributed to a cause-and-effect relationship. However, these results may serve to guide clinicians who treat obese patients, because it may be an additional benefit of weight loss.
    Urology 11/2011; 79(2):266-9. · 2.42 Impact Factor
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    ABSTRACT: An infant born at 38-weeks' gestation presented with ambiguous genitalia. Cytogenetic evaluation revealed an uncommon 45,X/46,X,idic(Y) mosaic karyotype. Pelvic ultrasonography, genitogram, and magnetic resonance imaging confirmed a long common urogenital sinus, vagina, cervix, unicornuate uterus, phallus, and bilateral intra-abdominal gonads resembling testes. The parents chose a male sex of rearing, and the infant underwent total abdominal hysterectomy, vaginectomy, bilateral gonadectomy, and first-stage hypospadias repair at 19 months of age. The histopathologic findings were consistent with ovotesticular disorder of sex development with a unique combination of testis and ovary on the left and testis and streak gonad on the right.
    Urology 05/2011; 78(5):1178-81. · 2.42 Impact Factor
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    International braz j urol: official journal of the Brazilian Society of Urology 01/2011; 37(6):781-2.
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    ABSTRACT: To perform a multi-institutional study to characterize CT-detected complications after PNL. Computed tomography (CT) is commonly performed after percutaneous nephrolithotomy (PNL). One benefit of this imaging modality is the detection of procedure-related complications. Presently, the incidence of such complications is not well-defined. PNL procedures performed at 5 stone referral centers between July 2007 and June 2008 were reviewed. All patients undergoing CT within 24 hours after surgery were selected for further analysis. All CT studies were reviewed by a staff radiologist. One-hundred ninety-seven patients satisfied the study inclusion criteria. A body mass index >30 was present in 27.5% of patients. Treated stone burden was staghorn in 70 (35.5%), >2 cm in 72 (36.5%), and <2 cm in 55 (28%). Six treated renal units (3%) were ectopic; 45.4% of calculi were predominantly lower pole. Thoracic complications encountered were atelectasis in 88 (44.7%), pleural effusion in 17 (8.6%), pneumothorax in 3 (1.5%), hemothorax in 2 (1%), and hydrothorax in 1 (0.5%). Renal complications were perinephric hematoma in 15 (7.6%), collecting system perforation in 4 (2%), subcapsular hematoma in 3 (1.5%), urinoma in 2 (1%), and pseudoaneurysm in 1 (0.5%). There was 1 trans-splenic nephrostomy without splenic hematoma. No injuries to hollow viscera were detected. Two patients (1%) were found to have ascites. Major post-PNL complications detected by CT are uncommon, and when encountered, they are generally amenable to conservative management.
    Urology 01/2011; 78(2):291-4. · 2.42 Impact Factor
  • Journal of Urology - J UROL. 01/2011; 185(4).
  • Michelle J Semins, Bruce J Trock, Brian R Matlaga
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    ABSTRACT: Administrative databases are increasingly used for epidemiological investigations. We performed a study to assess the validity of ICD-9 codes for upper urinary tract stone disease in an administrative database. We retrieved the records of all inpatients and outpatients at Johns Hopkins Hospital between November 2007 and October 2008 with an ICD-9 code of 592, 592.0, 592.1 or 592.9 as one of the first 3 diagnosis codes. A random number generator selected 100 encounters for further review. We considered a patient to have a true diagnosis of an upper tract stone if the medical records specifically referenced a kidney stone event, or included current or past treatment for a kidney stone. Descriptive and comparative analyses were performed. A total of 8,245 encounters coded as upper tract calculus were identified and 100 were randomly selected for review. Two patients could not be identified within the electronic medical record and were excluded from the study. The positive predictive value of using all ICD-9 codes for an upper tract calculus (592, 592.0, 592.1) to identify subjects with renal or ureteral stones was 95.9%. For 592.0 only the positive predictive value was 85%. However, although the positive predictive value for 592.1 only was 100%, 26 subjects (76%) with a ureteral stone were not appropriately billed with this code. ICD-9 coding for urinary calculi is likely to be sufficiently valid to be useful in studies using administrative data to analyze stone disease. However, ICD-9 coding is not a reliable means to distinguish between subjects with renal and ureteral calculi.
    The Journal of urology 07/2010; 184(1):190-2. · 4.02 Impact Factor
  • Michelle J Semins, Brian R Matlaga
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    ABSTRACT: Extracorporeal shock wave lithotripsy (SWL) was first introduced in 1980 and it rapidly revolutionized the treatment of stone disease. SWL is a non-invasive, outpatient procedure that now accounts for the majority of stone removal procedures. Since the introduction of first generation lithotripter, the Dornier HM3 machine, SWL devices have undergone many modifications secondary to limitations, in efforts to create a more effective and efficient way to treat stones and decrease possible morbidities. Herein, we review the evolution of the technology and advances in the instrumentation over the last three decades.
    Indian Journal of Urology 07/2010; 26(3):423-6.
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    ABSTRACT: Malabsorptive bariatric procedures such as Roux-en-Y gastric bypass (RYGB) place patients at risk for developing kidney stones. Stone risk factors after purely restrictive procedures such as gastric banding and sleeve gastrectomy are not well characterized. Therefore, we performed a study to examine urinary risk factors of patients who underwent restrictive gastric surgery for bariatric indications. A total of 18 patients were enrolled in the study; 14 underwent gastric banding and 4 underwent sleeve gastrectomy. All subjects collected 24-hour urine specimens; at least 6 months had elapsed between surgery and urine collection. Standard stone risk parameters were assessed, and comparisons were made with a group of normal adult nonstone-formers, routine stone-formers, and RYGB bariatric surgery subjects. Urinary oxalate excretion of the restrictive cohort was significantly less than the RYGB cohort (35.4 vs. 60.7 mg/d; P <.001) and not significantly different from that of the normal subjects (32.9 mg/d; P = .798) and routine stone-formers (37.2 mg/d; P = .997). There were no other significant differences in urinary parameters. Restrictive bariatric surgery does not appear to be associated with an increased risk for kidney stone disease. In particular, urinary oxalate levels were significantly less than those of RYGB subjects and not significantly different from routine stone-formers and nonstone-forming controls.
    Urology 04/2010; 76(4):826-9. · 2.42 Impact Factor
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    Michelle Jo Semins, Brian R Matlaga
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    ABSTRACT: Nephrolithiasis is a highly prevalent condition with a high recurrence rate that has a large impact on the quality of life of those affected. It also poses a great financial burden on society. There have been great advancements in the surgical treatment of stone disease over the past several decades. The evolution of surgical technique appears to have overshadowed the importance of prevention of stone disease despite evidence showing medical therapies significantly decreasing stone recurrence rates. Herein we review the metabolic evaluation of stone formers with the use of specific blood and urine tests. We complete our discussion with a review of the medical management of stone formers providing both general recommendations as well as reviewing focused therapies for specific metabolic abnormalities and medical conditions.
    Therapeutic Advances in Urology 02/2010; 2(1):3-9.
  • Journal of Urology - J UROL. 01/2010; 183(4).

Publication Stats

209 Citations
64.28 Total Impact Points

Institutions

  • 2013–2014
    • University of Pittsburgh
      Pittsburgh, Pennsylvania, United States
    • University of New Mexico
      Albuquerque, New Mexico, United States
  • 2007–2013
    • Johns Hopkins Medicine
      • Department of Urology
      Baltimore, MD, United States
  • 2012
    • CUNY Graduate Center
      New York City, New York, United States
    • Charité Universitätsmedizin Berlin
      • Department of Urology
      Berlin, Land Berlin, Germany
  • 2008–2010
    • Johns Hopkins University
      • Department of Surgery
      Baltimore, Maryland, United States
  • 2009
    • Johns Hopkins Bloomberg School of Public Health
      • Department of Health Policy and Management
      Baltimore, Maryland, United States