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Biomedical subjects

Brian R Matlaga

Publications and source records attributed to Brian R Matlaga.

At least 19 recordsLinked to original sources
PubMed2007

The role of Randall's plaques in the pathogenesis of calcium stones.

PURPOSE: Knowledge of the inciting lesion in kidney stone formation has remained rudimentary until quite recently. Randall theorized that areas of apatite plaque on the renal papillae would be an ideal site for an overgrowth of calcium oxalate to develop into a calculus. We reviewed in vivo data that have further defined the role of Randall's plaques in stone disease. MATERIALS AND METHODS: We examined a set of literature that tested 2 hypotheses, that is 1) Randall's plaques are a specialized disease that begins as apatite in a unique region of the kidney due to local driving forces and anatomy, and 2) stones that arise from causes different from common calcium oxalate stones do not necessarily arise on plaque. RESULTS: Intraoperative papillary and cortical biopsy specimens obtained during percutaneous nephrolithotomy from the kidneys of 3 types of stone formers (idiopathic calcium stone formers, patients with stones due to bariatric procedures and brushite stone formers) showed unique histopathological findings. CONCLUSIONS: The metabolic and surgical pathological findings in 3 distinct groups of stone formers demonstrate that the histology of the renal papillae from a stone former is particular to the clinical setting.

Calcium Oxalate↗
PubMed2007

Holmium laser treatment of benign prostatic hyperplasia: an update.

PURPOSE OF REVIEW: The surgical treatment of benign prostatic hyperplasia is a dynamic, evolving field. Holmium laser enucleation of the prostate has been one of the most rigorously analyzed interventions for benign prostatic hyperplasia. In the 12 months since July 2005, a number of important studies have been published concerning this technique. RECENT FINDINGS: In the 12-month period of this review, there have been a number of articles published on holmium laser enucleation of the prostate. Among these are five randomized controlled trials. These studies emphasize the unique advantages of holmium laser enucleation of the prostate over other surgical treatments for benign prostatic hyperplasia. SUMMARY: Holmium laser enucleation of the prostate is a more efficient procedure than competitor techniques, when grams of tissue removed per unit time are quantified. Additionally, holmium laser enucleation of the prostate is associated with a reduced length of catheterization and hospitalization when compared with other surgical therapies for men with benign prostatic hyperplasia. Outcome measures for men undergoing holmium laser enucleation of the prostate are in many cases superior to those of other modalities. It is likely that the completeness of adenoma removal with holmium laser enucleation of the prostate confers many of these advantages.

Holmium↗
PubMed2006

Percutaneous nephrolithotomy for ectopic kidneys: over, around, or through.

OBJECTIVES: The treatment of patients with complex urolithiasis in ectopic kidneys can be challenging. Because the location of an ectopic kidney can vary, each case requires a unique and, at times, unconventional approach. We reviewed the techniques we have developed to treat such patients, including laparoscopic-assisted tubeless, transhepatic, and transiliac percutaneous nephrolithotomy (PNL). METHODS: We performed a retrospective analysis of all patients with congenital pelvic kidneys who underwent PNL at our institution. Six patients underwent laparoscopic-assisted PNL, one underwent transiliac PNL, and one underwent transhepatic PNL. All laparoscopic-assisted procedures were performed tubeless, with an internalized ureteral stent placed at the conclusion of the procedure. RESULTS: All patients underwent successful PNL. On computed tomography, performed on the morning of postoperative day 1, all patients who underwent laparoscopic-assisted PNL were stone free. The patients who underwent transiliac PNL and transhepatic PNL required secondary procedures to attain a stone-free status. The mean length of hospitalization was 3 days for the laparoscopic-assisted cohort, 1 day for the transhepatic patient, and 3 days for the transiliac patient. CONCLUSIONS: For the patient with a large or complex stone burden in an ectopic kidney, laparoscopic-assisted PNL is the optimal treatment. Performing such a procedure tubeless may be associated with a reduced hospital stay. For those patients with a hostile peritoneal cavity owing to prior surgical exploration, consideration should be given to a more individualized approach.

Adult↗
PubMed2006

Use of lower pole nephrostomy drainage following endorenal surgery through an upper pole access.

PURPOSE: PNL via an UP puncture is efficient for treating complex stone disease. Access via the UP can provide better visualization, allowing greater stone clearance with a rigid instrument due to its more favorable alignment with the axis of the intrarenal collecting system. However, the presence of a NT through the upper pole tract, especially with a supracostal puncture, can generate significant patient discomfort. We reviewed our experience with a technique using tubeless UP access for PNL with concomitant placement of a NT via a LP calix. MATERIALS AND METHODS: We performed a retrospective review of our experience using tubeless UP access for PNL with concomitant placement of an LP NT for postoperative drainage. Patient demographics, the number and location of accesses, stone size, stone-free rates, concurrent/additional procedures and complications were recorded. RESULTS: A total of 63 tubeless UP accesses were performed in 62 patients undergoing PNL, including unilateral access in 61 and bilateral access in 1. Supracostal UP punctures were used in 58 patients, including 40 above the 12th, 17 above the 11th and 1 above the 10th rib. Each patient underwent at least 2 accesses and 3 had 3 or more accesses placed. LP access was nondilated in 37 patients and dilated in 26. Of the patients 56.6% were stone-free after a single procedure, increasing to 96.2% following secondary procedures. Three of the 62 patients (4.8%) required transfusion, 3 (4.8%) required intervention for pleural morbidity and 1 (1.6%) required a stent for a nonsealing upper pole access. CONCLUSIONS: Tubeless UP access provides maximal efficiency for stone clearance during PNL, while minimizing the morbidity of an intercostal tube.

Adolescent↗
PubMed2006

Changing composition of renal calculi in patients with neurogenic bladder.

PURPOSE: Renal calculi are a significant source of morbidity for patients with neurogenic bladder. Calculi from patients with NB have traditionally been composed primarily of struvite and carbonate apatite secondary to chronic urea-splitting bacteriuria. In the current era there have been great improvements in the urological rehabilitation of patients with NB. We defined the composition of renal calculi in a contemporary cohort of patients with NB due to spinal cord injury or myelomeningocele who underwent percutaneous nephrolithotomy. MATERIALS AND METHODS: We performed a retrospective evaluation of all patients with NB due to SCI or MM who underwent PNL between January 2002 and January 2005. RESULTS: A total of 32 patients with NB (14 with SCI, 18 with MM) underwent PNL in this period. Stones were infectious in etiology in 37.5% (12 struvite/carbonate apatite) and metabolic in 62.5% (1 uric acid, 2 calcium oxalate monohydrate, 2 brushite, 6 hydroxyapatite, 9 mixed hydroxyapatite/calcium oxalate). All patients with struvite calculi were infected with urea-splitting bacteria on preoperative urine culture. CONCLUSIONS: Patients with neurogenic bladder are traditionally thought to harbor infection related calculi. These data demonstrate that many contemporary patients will be found to have calculi of a metabolic etiology. Although patients with NB still have renal calculi, advances in urological treatment may have affected the composition of their calculi, as metabolic stones are becoming more commonly identified. When metabolic components are identified, stone activity may be attenuated with appropriate metabolic evaluation, pharmacological therapies and dietary modifications.

Adolescent↗
PubMed2006

Endoscopic evidence of calculus attachment to Randall's plaque.

PURPOSE: It has been proposed that calcium oxalate calculi begin as small stones attached to the renal papillae at sites of Randall's plaque. However, no study has investigated the prevalence of attached stones in calcium oxalate stone formers or the relationship between stone attachment site and Randall's plaque. In this study we used endoscopic examination of renal papillae in stone formers undergoing percutaneous nephrolithotomy to investigate both issues. MATERIALS AND METHODS: Idiopathic calcium oxalate stone formers undergoing PNL for stone removal were enrolled in this study. Multiple papillae were examined and images were recorded by digital video. The presence or absence of papillary plaque and attached stones was noted, as was the site of stone attachment. RESULTS: In 23 patients, 24 kidneys and 172 renal papillae were examined. All kidneys were found to have papillary plaque and 11 of the patients had attached stones. Most papillae (91%) contained plaque. CONCLUSIONS: The prevalence of attached stones in calcium oxalate stone formers (48%) is greater than that previously reported for the general population. Attachment appears to be on Randall's plaque. The high prevalence of attached stones and the appearance of the attachment site are consistent with a mechanism of calcium oxalate stone formation in which stones begin as plaque overgrowth.

Calcium Oxalate↗
PubMed2006

Acute effects of percutaneous tract dilation on renal function and structure.

BACKGROUND: Percutaneous nephrolithotomy (PCNL) is performed on a routine basis for the rapid and efficient removal of large caliceal stones. After percutaneous puncture, rigid dilators or an inflatable balloon are used to dilate the nephrostomy tract to allow access to the collecting system for stone removal. Little is known of the acute impact of tract dilation procedures on renal function. MATERIALS AND METHODS: We compared renal hemodynamic and excretory function in female pigs immediately before and up to 5 hours after percutaneous nephrostomy (PCN) using sequential Amplatz dilators (N = 8) or Nephromax balloon inflation (N = 7) and control pigs with no PCN access (N = 8). We also examined renal function in patients undergoing PCNL. RESULTS: The two PCN procedures produced a renal lesion of comparable size and morphology, as well as similar changes in renal function. Glomerular filtration rate (GFR), renal plasma flow (RPF), and urinary sodium excretion (U(Na)V) were significantly reduced in Amplatz- and Nephromax-treated kidneys throughout the 5-hour observation period, by about 50%, 60%, and 80%, respectively. In control pigs, GFR and RPF remained stable and U(Na)V declined progressively to about 50% of baseline over the course of the experiment. The contralateral kidney showed changes in renal function similar to those in the PCN-treated or control kidney in all three groups. A retrospective analysis of 196 adults with normal renal function who underwent unilateral PCNL using the Nephromax balloon dilator revealed a significant increase in serum creatinine of 0.14 mg/dL at 1 day. CONCLUSION: Both animal and human studies show that PCN is associated with an acute decline in renal function.

Animals↗
PubMed2006

Pre-percutaneous nephrolithotomy opacification for caliceal diverticular calculi.

Caliceal diverticula harbor calculi in as many as 50% of cases. Such stones rarely pass spontaneously. Various stone-removal techniques have been used, with percutaneous techniques generally having the best results. In patients with nonradiopaque stones or in whom the diverticulum does not opacify when contrast is instilled retrograde or by intravenous urogram, contrast can be instilled directly into the cavity with CT or ultrasound guidance. Three such cases are described, with good results.

Adolescent↗
PubMed2006

Calcium oxalate calculi found attached to the renal papilla: Preliminary evidence for early mechanisms in stone formation.

BACKGROUND: Calculi are commonly found attached to the renal papilla in calcium oxalate (CaOx) stone formers, but the mechanisms by which stones form in this manner are not well established. MATERIALS AND METHODS: Data are presented from three attached stones collected from different patients. Stone morphology and composition were determined using micro computed tomography (CT) and infrared microspectrometry. RESULTS: One of the stones was composed of CaOx with a peripheral region of apatite, such as might have come from a Randall's plaque. Another stone was covered with large CaOx crystals but contained at least two layers of apatite, with no apatite regions exposed at the surface. The third stone contained CaOx with inclusions of apatite and more apatite on its surface, along with a substantial volume of poorly mineralized material that could not be identified. CONCLUSIONS: The complexity of these stones and their differing morphologies do not by themselves allow inference of the mechanism of stone formation. Future work will require the careful documentation of attached stones on the papilla, as well as study of the papilla after the stone has been removed, before it can be determined whether such diverse CaOx stones originate from the same or different underlying etiologies.

Apatites↗
PubMed2006

Holmium laser enucleation of the prostate for prostates of >125 mL.

OBJECTIVE: To examine a group of patients treated with holmium laser enucleation of the prostate (HoLEP) and with the bladder outlet obstructed by an exceptionally large (>125 mL) prostate, as such men are often not considered candidates for endoscopic treatments and historically have required open surgery. PATIENTS AND METHODS: We analysed retrospectively all patients with prostates of > 125 mL on transrectal ultrasonography (TRUS) who underwent HoLEP between January 2000 and January 2005. RESULTS: Eighty-six patients were identified; their mean (range) age was 72.6 (48-90) years and prostate volume 170.2 (125-309) mL. Their mean preoperative prostate-specific antigen (PSA) level was 9.82 ng/mL and preoperative American Urologic Association symptom score (AUA-SS) was 19.6. The mean operative duration and hospital stay were 128.1 min and 26.1 h, respectively. The mean weight of tissue enucleated was 140.2 g. At the 1-month follow-up the mean AUA-SS (63 men) was 8.4 and at 6 months (35 men) it was 6.4. The mean serum PSA level in 48 patients was 0.96 ng/mL, a reduction of 90%. TRUS measurements in 20 patients gave a mean prostate volume of 30.8 mL, a reduction of 82%. At the 1-year follow-up the mean AUA-SS of 22 patients was 5.1. CONCLUSIONS: The present report details the largest series of patients, with the largest mean prostate size, treated by any endoscopic surgical method. HoLEP may be the ideal treatment for men with prostates of > 125 mL with symptoms of bladder outlet obstruction.

Aged↗
PubMed2005

Ureterocalicostomy: a contemporary experience.

OBJECTIVES: To report our contemporary experience with ureterocalicostomy to determine whether the indications or results have changed in modern practice. Ureterocalicostomy is a well-established treatment for patients with complicated ureteropelvic junction (UPJ) obstruction and other forms of proximal ureteral obstruction. Although both retrograde and antegrade endourologic interventions have become accepted forms of management, the success rates do not approach those of open or even laparoscopic interventions, potentially leading to a greater number of patients with treatment failure and the need for more complicated reconstruction. METHODS: Between July 1991 and February 2004, 11 patients (4 women and 7 men), aged 19 to 68 years (mean 38), underwent open surgical ureterocalicostomy. The indications for surgery were primary UPJ obstruction in 4, failed cutting balloon incision for UPJ obstruction in 3, proximal ureteral stricture after ureteroscopic stone removal in 2, and obliterated UPJ after percutaneous nephrolithotomy and failed antegrade endopyelotomy in 1 patient each. RESULTS: Hospitalization ranged from 4 to 7 days (mean 5.1). No patient experienced a significant perioperative complication. With follow-up ranging from 5 to 32 months (mean 10.1), relief of obstruction was evident in all patients as documented by intravenous urography or nuclear renography. Furthermore, differential function on the involved side improved from a mean of 54.6% preoperatively to 60.1% postoperatively (P <0.05). CONCLUSIONS: The spectrum of indications for ureterocalicostomy has changed, although excellent results can still be achieved. Although laparoscopic approaches are currently being evaluated, most patients currently undergoing this reconstructive procedure still require open operative intervention.

Adult↗
PubMed2005

Ureteroscopic management of renal calculi in anomalous kidneys.

OBJECTIVES: To review our experience with ureteroscopy in treating patients with renal calculi in anomalous kidneys and to evaluate the efficacy of this approach. METHODS: Eight patients with renal calculi in anomalous kidneys who were managed by ureteroscopic procedures were identified. Demographic information, preoperative stone burden, operative information (ureteroscope size, lithotrite used, instruments used, duration of surgery, complications, stenting), follow-up imaging, and complications were obtained from the medical record. This information was analyzed to determine the most frequently used instruments and stone-free rates. RESULTS: Our cohort consisted of 4 patients with horseshoe kidneys (HSK) and 4 patients with pelvic kidneys (PK) (6 male, 2 female, mean age, 50.6 years). The average preoperative stone burden of the 11 treated calculi was 1.4 cm, with 5 stones located in the renal pelvis, 2 in the upper pole, and 4 in lower pole calyces. A 7.5F flexible ureteroscope, holmium laser lithotripsy, and nitinol baskets and graspers were used in all patients. Six patients had complete clearance of the stone on postoperative imaging (75% HSK, 75% PK), with 88% of patients asymptomatic after their procedure. No patients required additional surgical intervention. CONCLUSIONS: Flexible ureteroscopy with holmium laser lithotripsy and the use of nitinol baskets and graspers provides a reasonable alternative to shock wave lithotripsy in the management of patients harboring renal calculi in anomalous kidneys. In addition, ureteroscopy can be considered a primary option for managing select patients with symptomatic stones in PKs before a percutaneous surgical approach.

Adult↗
PubMed2005

Holmium laser enucleation of the prostate: a comparison of efficiency measures at two institutions.

BACKGROUND AND PURPOSE: Holmium laser enucleation of the prostate (HoLEP) is perceived to be technically difficult, time consuming, and inefficient. We assessed the efficiency of HoLEP by documenting the technical features of the procedure at two hospitals located on different continents. PATIENTS AND METHODS: A retrospective analysis of all patients who underwent HoLEP at the Methodist Hospital of Indiana and Tauranga Hospital in New Zealand was performed. A series of 40 patients from the Indiana cohort were pair-matched, by the weight of prostate tissue retrieved, with 40 patients from the New Zealand cohort. Enucleation time and morcellation time were compared in the two groups. RESULTS: The mean weight of the tissue retrieved from the Indiana cohort was 27.1 g and that from the New Zealand cohort was 22.9 g (P = 0.41). The mean enucleation times were 47.6 minutes and 29.2 minutes, respectively (P < 0.001). The mean morcellation times were 9.9 minutes and 7.7 minutes (P = 0.201). The mean rates of enucleation were 0.58 g/min and 0.71 g/min (P = 0.17). The mean rates of morcellation were 3.4 g/min and 4.3 g/min (P = 0.20). The HoLEP efficiency increased as a function of gland size (R(2) = 0.56). CONCLUSIONS: Holmium laser enucleation of the prostate is a reproducible technique, as there is little variation in efficiency from one surgeon to another. Furthermore, the efficiency of HoLEP increases as prostate size increases, which suggests that HoLEP may be an ideal treatment for men with large prostates.

Holmium↗
PubMed2005

Holmium laser enucleation of the prostate for men with urinary retention.

PURPOSE: Holmium laser enucleation of the prostate (HoLEP) is an established procedure for the treatment of patients with benign prostatic hyperplasia. We performed a study to examine a group of patients in urinary retention treated by HoLEP. MATERIALS AND METHODS: A retrospective analysis of 164 consecutive patients with urinary retention who underwent HoLEP between January 2000 and August 2004 was performed. RESULTS: Mean patient age was 72.1 years (range 34 to 95). Mean duration of urinary retention was 28.9 days (range 2 to 365). Mean preoperative transrectal ultrasound measured prostate volume was 107.1 cc (range 5 to 242). Mean weight of resected tissue was 81.9 grams (range 2.5 to 271). Mean duration of postoperative catheterization and hospitalization was 22.5 hours (range 2 to 240) and 33.7 hours (range 2 to 144), respectively. All patients were able to void following treatment and remain catheter free. CONCLUSIONS: HoLEP is an effective treatment, with low morbidity, for patients with urinary retention. These results suggest that HoLEP may be the ideal treatment for men with urinary retention due to benign prostatic obstruction.

Adult↗
PubMed2004

Radiofrequency ablation of renal tumors.

Radiofrequency ablation (RFA) of renal tumors is a relatively new treatment modality in the armamentarium of urologic surgeons. One of the challenges of this technique is attaining a zone of tissue destruction sufficient enough to kill the targeted tumor. Technologic innovations have aided in this effort. The clinical experience with RFA of renal tumors suggests that small, exophytic tumors may be more readily ablated. Although there is much optimism with regard to this technology, further study is required to better define the oncologic efficacy and refine proper patient selection.

Carcinoma, Renal Cell↗
PubMed2004

Percutaneous nephrostolithotomy: predictors of length of stay.

PURPOSE: Percutaneous nephrostolithotomy (PNL) is commonly used to treat patients with complex renal calculi. A goal at our medical center is to discharge patients home less than 24 hours after PNL. We performed a study to determine factors that caused patients to be hospitalized longer than this period. MATERIAL AND METHODS: The available hospital records and office charts of 133 consecutive patients undergoing initial PNL at our institution between January 1, 1999 and December 31, 2000 were reviewed. All PNL procedures were performed by one of us using a (DGA) 1-stage technique. Mean patient age was 52 years (range 25 to 84). Of the subjects 85 were male and 48 were female. RESULTS: A total of 91 patients (68%) were discharged home less than 24 hours after surgery. The overall stone-free rate was 91%. Mean length of stay in the entire group was 1.97 days. Mean length of stay in those hospitalized longer than 24 hours was 4.12 days. Mean operative time, including time to obtain access, was 188.6 minutes. Multivariate analysis demonstrated that neurogenic bladder, endocrine comorbidity and perioperative complications were factors associated with a length of stay of greater than 24 hours. Univariate analysis demonstrated that preoperative urinary tract infection and infection related calculi were also associated with a length of stay of greater than 24 hours. CONCLUSIONS: The majority of patients undergoing PNL can be discharged home less than 24 hours after surgery. Patients with neurogenic bladder, those with endocrine comorbidity, those who sustain significant perioperative complications and those harboring stones associated with urinary tract infection or preoperative urinary tract infection are more likely to require longer hospitalization.

Adult↗