Hounsfield unit density in the determination of urinary stone composition.

OBJECTIVES: Noncontrast computed tomography (NCCT) has emerged as the diagnostic study of choice in the evaluation of acute flank pain. Recent in vitro studies have suggested that NCCT can be used to predict the composition of urinary stones on the basis of differences in radiodensity (measured in Hounsfield units, HUs). We sought to determine whether the analysis of in vivo urinary stones seen on NCCT could predict their composition. METHODS: Between March 1997 and August 1999, 100 pure stones from patients seen at the Wilford Hall Medical Center in San Antonio, Texas were submitted for analysis. All had been visualized by NCCT before stone passage or retrieval. A General Electric High-Speed Advantage CT scanner evaluated most of these patients by a "flank pain protocol" (ie, helical technique with breath-holding at 120 kV, 200 mA with 5 mm collimation). Each scan was interpreted by one of two staff radiologists who measured the HUs for each stone. A statistical comparison was made between the stone composition and radiodensity. To allow for subsequently observed increases in radiodensity with increasing stone size regardless of composition, the HU value was divided by each stone's largest transverse diameter in millimeters to give the HU density. A statistical comparison was then made between stone composition and HU density. RESULTS: No significant difference was noted between the HU values of calcium oxalate and calcium phosphate stones, and thus they were analyzed collectively as "calcium stones." When the HU values of calcium (n = 87), uric acid (n = 7), struvite (n = 4), and cystine (n = 2) stones were compared, the overlap of ranges precluded accurate identification, and the mean HU values were not significantly different from one another. There was less overlap noted when comparing the HU densities of the stones studied, and no noncalcium stone had an HU density greater than 76 HU/mm. Using one-way analysis of variance, significant differences were noted between the mean HU density of calcium (105 +/- 43) and uric acid (50 +/- 24) stones (P = 0.006). A trend toward significance was found between the mean HU density of the calcium and struvite stones (53 +/- 28, P = 0.073). No significant differences were found among the other stones. CONCLUSIONS: HU density compared with the HU value alone better characterized differences in radiodensities among urinary stones; calcium stones can be distinguished from uric acid stones on the basis of this value. However, neither the HU density nor the mean HU value was able to identify urinary stones in vivo.

Walking, chair rising, and stair climbing after total knee arthroplasty: patellar resurfacing versus nonresurfacing.

During the past decade, the technology and design of knee joint prostheses has progressed considerably. However, there is still much controversy on whether resurfacing the patella during routine total knee arthroplasty (TKA) is necessary. This study compares the biomechanics of the lower limb in patients after TKA with and without patellar resurfacing during level walking, stair climbing, and chair rising. Eighteen patients who underwent TKA by two different surgeons using the same prosthesis were studied after full rehabilitation while walking, stair climbing, and chair rising. Patients were divided between those who were resurfaced and those who were not resurfaced. An aged-matched control population was recruited for comparison. The Hospital for Special Surgery Knee Rating Scale was used to gather clinical information. Kinematic and kinetic parameters were collected using a 5-camera Motion Analysis System and an AMTI OR6-5 force platform. For level walking, patients were asked to walk at a self-selected speed down an 8-m walkway. For stair climbing, patients were asked to climb a 4-step staircase without handrail support and for chair rising, patients were asked to rise from a chair that was positioned at the height of their knee joint line. Five trials for each side were recorded for averaging and statistical analysis. Temporal-spatial parameters and kinematic and kinetic variables at the knee joint were tested for significance using the repeated measures analysis of variance (ANOVA). There were no significant differences in the biomechanics of walking, stair climbing, or chair rising between patients after TKA with and without a resurfaced patella.

Incidence of fecal and urinary incontinence following radical perineal and retropubic prostatectomy in a national population.

PURPOSE: Since 1991 we have performed more than 300 anatomical radical perineal prostatectomies at Brooke Army and Wilford Hall Medical Centers, and were initially aware of 8 patients who presented with unsolicited postoperative fecal incontinence. We determined the incidence of fecal and urinary incontinence following radical prostatectomy, defined parameters to identify patients at risk for fecal complaints following radical prostatectomy, and estimated the impact of fecal incontinence on lifestyle and activities. MATERIALS AND METHODS: Initially a validated 26-question telephone survey was used to evaluate 227 patients who had previously undergone radical prostatectomy at 1 of our 2 institutions. Based on results of the telephone survey a national survey was mailed to 1,200 radical prostatectomy patients randomly selected from a nationwide database of Department of Defense health care system beneficiaries. All patients had undergone radical perineal or retropubic prostatectomy at least 12 months before being contacted for the survey. RESULTS: Responses to the telephone survey from 227 patients revealed that fecal incontinence was a problem after radical retropubic (5%) and perineal (18%) prostatectomy and less than 50% of those with fecal incontinence had told the physician. Our mail survey (response rate 80% and 78% usable for analysis, 784 radical perineal and 123 perineal) strongly indicated that fecal incontinence after radical prostatectomy is a problem nationwide. Frequency of fecal incontinence (daily, weekly, monthly or less than monthly occurrences) was significantly higher among radical perineal (3, 9, 3 and 16%) compared to retropubic prostatectomy (2, 5, 3, and 8%) patients (p=0.002). Fecal incontinence had a significant negative effect on patient social or entertainment activities (p=0.029), and travel and vacation plans (p=0.043). Radical perineal compared to retropubic prostatectomy patients were more likely to wear a pad for stool leakage (p=0.013), experienced more accidents (p=0.001), had larger amounts of stool leakage (p=0.002) and had less formed stools (p=0.001). Of radical perineal prostatectomy patients only 14% and of retropubic only 7% with fecal incontinence had ever told a health care provider about it, even when the incontinence was severe. Responses to our survey concerning urinary incontinence showed that radical perineal prostatectomy patients had a lower rate of urinary incontinence immediately after prostatectomy compared to retropubic (79 versus 85%, p=0.043). A higher proportion of perineal patients reported that all urinary leakage had ceased, that is full continence had returned (perineal 70%, retropubic 53%, p=0.001). A smaller proportion of perineal patients found it necessary to wear a pad to protect from urinary incontinence (perineal 39%, retropubic 56%, p=0.004). CONCLUSIONS: Fecal incontinence following radical prostatectomy occurs more frequently than previously recognized. In general fecal incontinence among radical perineal and retropubic prostatectomy patients surpasses the expected incidence rate of 4% for this age group (60 to 70 years) but incidence is significantly higher for radical perineal prostatectomy patients. However, radical perineal prostatectomy patients have a significantly lower incidence of urinary incontinence than those treated with retropubic prostatectomy. Surgeons who perform radical retropubic and perineal prostatectomy should be aware of the possibility of fecal and/or urinary incontinence and associated symptoms.

A logical coronal pattern classification of 2,000 consecutive idiopathic scoliosis cases based on the scoliosis research society-defined apical vertebra.

STUDY DESIGN: Two thousand consecutive idiopathic scoliosis records and radiographs were reviewed for coronal pattern typing and categorization, based on Scoliosis Research Society definitions of the apical vertebra. Apical frequency was determined for each of the patterns identified, and represents a database from a large series of cases for the already accepted Scoliosis Research Society definitions. OBJECTIVES: To identify and numerically pattern-type a large series of idiopathic coronal curves, for the basic purpose of written and oral communication. Some pattern types were not described previously. SUMMARY OF BACKGROUND DATA: Although spinal deformity must be considered three dimensional for treatment in 1998, no comprehensive, databased, and user friendly coronal or sagittal classification of idiopathic scoliosis has been reported. METHODS: Two thousand idiopathic curve patterns from charts and radiographs were reviewed and the coronal patterns categorized by the apical vertebra. The resulting classification was tested for inter- and intraobserver reliability by 12 spine surgeons and 6 orthopedic residents. Apical frequencies were determined for each pattern type. RESULTS: Twenty-one pattern categories were identified, and all were right or left mirror image patterns (except for a quadruple pattern) that permitted separation into 11 types. Incorporating the widely recognized five numbered King types mad pattern recognition simple. Interobserver reliability testing was 98.2%. The left single thoracic curve pattern was included in this classification because only 9 (20.4%) of 44 patients with left thoracic curves had intraspinal pathology. CONCLUSION: Two thousand consecutive idiopathic coronal curve patterns separated into eleven readily identifiable types, and incorporating the widely referenced five King types, makes recognition simple for purposes of identification and communication. Sagittal and 3D factors excluded from this classification are equally important in the process of treatment decisions. Apical frequency data determined in this study lends credence to Scoliosis Research Society definitions for idiopathic curve patterns.

The pars interarticularis stress reaction, spondylolysis, and spondylolisthesis progression.

OBJECTIVE: To review the classification, etiology, clinical and radiologic evaluation, and management of the pars interarticularis stress reaction, spondylolysis, and spondylolisthesis progression. DATA SOURCES: Grateful Med was searched from 1980 to 1998 using the terms "spondylolysis," "spondylolisthesis," "female athlete" "spondylogenic," and "pars interarticularis." DATA SYNTHESIS: The progression from pars interarticularis stress reaction through spondylolysis to spondylolisthesis is common in adolescent athletes, and, because of hormonal influences and cheerleading and gymnastic maneuvers, females are particularly at risk. Proper diagnosis and management include a thorough evaluation, radiographs (possibly with technetium bone scan or single-photon emission computed tomography), activity modification, dietary counseling, a therapeutic exercise program focusing on proper trunk and hip muscle strength and extensibility balances, and education regarding proper back postures, positioning, lifting mechanics, and jump landings. CONCLUSIONS/RECOMMENDATIONS: The athletic trainer plays an integral part in managing this injury progression, particularly with identifying at-risk individuals and intervening appropriately.