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Biomedical subjects

Craig A Peters

Publications and source records attributed to Craig A Peters.

At least 19 recordsLinked to original sources
PubMed2007

Robotic surgery in the pediatric airway: application and safety.

OBJECTIVE: To assess the application and safety of transoral robotic surgery in the pediatric airway. DESIGN: An institutional review board-approved study. Experimental laryngeal surgery was performed on 4 pediatric cadaver larynxes as controls. Application of robotic equipment for laryngeal surgery was attempted on 5 patients. SETTING: Tertiary care pediatric medical center. PATIENTS: Five patients with laryngeal cleft and 4 pediatric cadaver larynxes. INTERVENTIONS: (1) The da Vinci Surgical Robot (Intuitive Surgical Inc, Sunnyvale, Calif) was used on 4 cadaver larynxes and assessed for the dexterity, precision, and depth perception that it allowed the surgeon during laryngeal surgery. Procedures were documented with still and video photography. (2) The da Vinci Surgical Robot was used through a transoral approach to attempt repair of a laryngeal cleft in 5 pediatric patients who were under spontaneously breathing general anesthesia. RESULTS: (1) Use of the surgical robot on cadaver larynxes provided great dexterity and precision, delicate tissue handling, good 3-dimensional depth perception, and relatively easy endolaryngeal suturing. (2) The surgical robot could not be used for repair of laryngeal cleft on 3 patients owing to limited transoral access. However, 1 patient with a type 1 laryngeal cleft and 1 patient with a type 2 laryngeal cleft underwent transoral robotic repair with great success. CONCLUSIONS: Surgical robots provide the ability to manipulate instruments at their distal end with great precision, increased freedom of movement, and excellent 3-dimensional depth perception. The size of the equipment can be a limiting factor with regard to the application and success of the transoral approach to airway surgery. We believe that further advances in device technology and a new generation of robotic equipment will facilitate the incorporation of surgical robotics in the advancement of minimally invasive endoscopic airway surgery.

Adolescent↗
PubMed2006

Pediatric robot assisted laparoscopic dismembered pyeloplasty: comparison with a cohort of open surgery.

PURPOSE: We assessed the usefulness of RALP in children and compared an age matched cohort undergoing OPN to RALP for safety, efficacy, operative time, blood loss, in-hospital narcotic use and LOS. MATERIALS AND METHODS: We performed a retrospective case-control study from 2000 to 2004 of 33 patients undergoing RALP and 33 undergoing OPN. Average age of each group was not significantly different (RALP 7.8 years vs OPN 7.6 years, p = 0.75). Mean followup of RALP and OPN groups was 10 and 21 months, respectively. RESULTS: Etiology of the obstruction was not significantly different. Mean operative time was significantly less for OPN (181 minutes vs 219 minutes for RALP, p = 0.031). As RALP experience increased, operative times improved and approached the OPN experience. RALP complications included 1 patient requiring reoperative surgery vs no complications in the OPN group (p = 0.15). Patients undergoing RALP had a mean LOS of 2.3 days compared to 3.5 days for OPN (p <0.001). Total narcotic requirements were significantly less in the RALP group (p = 0.001). All patients in the OPN and 31 in the RALP group had either resolution of hydronephrosis, improvement in drainage or relief of symptoms. CONCLUSIONS: We documented the safety and efficacy of RALP in children. RALP showed advantages of decreased hospital stay, decreased narcotic use and operative times approaching those of open surgery. RALP is an option for pyeloplasty, and as robotic technology improves, this method of repair may become the minimally invasive treatment of choice.

Adolescent↗
PubMed2006

Radiation exposure reduction during voiding cystourethrography in a pediatric porcine model of vesicoureteral reflux.

PURPOSE: To compare grid-controlled variable-rate pulsed fluoroscopy (GCPFL) and continuous fluoroscopy (CFL) for the reduction of radiation exposure during voiding cystourethrography (VCUG) in a pediatric porcine model of vesicoureteral reflux. MATERIALS AND METHODS: Institutional animal care and use committee approval was obtained. Vesicoureteral reflux was simulated in four pigs, and 48 VCUG studies were performed (24 with GCPFL, 24 with CFL). VCUG was performed at abdominal girths of 8-10 cm (group 1, simulates human newborn to 6-month-old infant), 12-13 cm (group 2, simulates 2-3-year-old child), and 15-17 cm (group 3, simulates 10-year-old child). An electronic device calculated total radiation exposure during fluoroscopy and image recording. With five-point ordinal scales, VCUG images were scored independently for anatomic conspicuity and overall diagnostic quality by two radiologists (radiologists A and B). An analysis of variance was used to compare radiation exposures and fluoroscopy times between GCPFL and CFL and to determine whether radiation exposure and fluoroscopy time were dependent on the pig's abdominal girth. The Pearson product-moment correlation coefficient was used to assess whether fluoroscopy time was correlated with radiation exposure. Anatomic conspicuity and diagnostic quality scores were compared by means of the Wilcoxon signed rank test. RESULTS: Results of analysis of variance revealed that GCPFL resulted in a significant reduction in total radiation exposure compared with CFL for each of the three groups (P < .05 for each comparison), and this reduction was most marked in the larger animals. There were no significant differences in diagnostic quality of the recorded VCUG images (P > .05). Anatomic conspicuity was not significantly different for groups 2 and 3, but there was a significantly higher score for GCPFL in group 1 for radiologist A (P = .04). CONCLUSION: By using GCPFL in the performance of VCUG in a pediatric porcine model of vesicoureteral reflux, total radiation exposure can be reduced by a factor of 4.6-7.5 lower than with CFL, and diagnostic-quality images can be obtained.

Analysis of Variance↗
PubMed2006

Fetal sheep development on ultrasound and magnetic resonance imaging: a standard for the in utero assessment of models of congenital abnormalities.

OBJECTIVE: To establish normative data for the size, conspicuity, and imaging characteristics of normal developing fetal sheep organs on ultrasound (US) and magnetic resonance (MR) imaging. METHODS: US and MR images of ten normal pregnant sheep, at 40, 65, 90, 115, and 140 gestational days (term = 145 days), were scored for organ conspicuity and imaging characteristics. Imaging biometry was correlated with specimens. Gestational age-based growth parameters were modeled using regression. RESULTS: Imaging biometry showed excellent correlation with specimens. Kidney, bladder, stomach, lung, liver, and spine were seen well from 65 days to term by US. More organs were consistently visible from 90 days to term by MR than by US. Most organ imaging characteristics tended not to change throughout gestation. CONCLUSION: Normal fetal sheep biometry, organ conspicuity, and imaging characteristics are established for US and MR and have potential use for the in utero assessment of sheep models of congenital abnormalities.

Animals↗
PubMed2005

Ectopic prostate tissue within the processus vaginalis: insights into prostate embryogenesis.

We report an 11-year-old boy who presented with a scrotal mass superior to the epididymis in the processus vaginalis. The mass consisted of prostate tissue, including glands and fibromuscular stroma, communicating with a spermatocele. Strong immunostaining for prostate-specific antigen was seen in the glandular epithelium. Immunostaining for peanut agglutinin highlighted the luminal plasma membrane in a subset of epithelial cells, mainly those located around the periphery of the nodule. To the best of our knowledge, this represents the first report of a pediatric patient with ectopic prostate tissue located outside the urinary tract and the first instance altogether of ectopic prostate noted at this location. The young age of the patient, the lesion's constituents, and its location suggest that the finding represents a disorder of development.

Child↗
PubMed2005

Pediatric retroperitoneal laparoscopic partial nephrectomy: comparison with an age matched cohort of open surgery.

PURPOSE: We assessed the clinical usefulness of laparoscopic retroperitoneal partial nephrectomy (LRPN) in children by comparing an age matched cohort of pediatric patients undergoing open partial nephrectomy (OPN) to those undergoing LRPN for safety, efficacy, operative time, blood loss, inpatient narcotic use and length of hospitalization. MATERIALS AND METHODS: A retrospective case-control study was performed of 1 group undergoing LRPN (treatment arm) and 1 undergoing OPN (controls) between 1997 and 2003. The 14 patients in each group were matched by age (mean 1.9 years in LRPN group vs 2.2 years in OPN group, p = 0.98) and gender. RESULTS: All patients had duplication anomalies. Mean operative time was 194 minutes in the LRPN group and 193 minutes in the OPN group (p = 0.83). The single complication in the LRPN group was a urinoma that did not require intervention. There were no complications in OPN group. LRPN patients had a mean hospitalization of 1.7 days compared to 4.7 days in OPN patients (p = 0.001). Intraoperative narcotic requirements were higher in the LRPN group (0.59 vs 0.22 mg/kg, p = 0.04). Postoperative narcotic requirements were significantly less in the LRPN group (0.44 vs 1.53 mg/kg, p = 0.04). Similar findings were noted in a subanalysis of patients younger than 2 years. All patients had documented postoperative ipsilateral renal growth. Mean followups in the treatment and control groups were 26 and 25 months, respectively. CONCLUSIONS: Retroperitoneal laparoscopic partial nephrectomy in small children was shown to be safe and effective. It had equivalent operative times, and decreased postoperative narcotics and hospitalization relative to the open approach, and, therefore, is a potentially advantageous technique.

Case-Control Studies↗
PubMed2005

Balanitis xerotica obliterans in boys.

PURPOSE: Balanitis xerotica obliterans (BXO) is a chronic dermatitis of unknown etiology most often involving the glans and prepuce but sometimes extending into the urethra. We report our 10-year experience with BXO in pediatric patients. MATERIALS AND METHODS: Our pathology database was queried for all tissue diagnoses of BXO from 1992 to 2002. Available charts were reviewed and patient presentation, clinical and referral history, operative procedure(s) and postoperative course were recorded. RESULTS: A total of 41 patients had a tissue confirmed diagnosis of BXO. Median patient age was 10.6 years. Of the patients 85% were 8 to 13 years old and all had referrals available for review. The most common referral diagnoses were phimosis (52%), balanitis (13%) and buried penis (10%). No patient had the diagnosis of BXO at referral. Of the patients 19 (46%) underwent curative circumcision or redo circumcision and had no recurrence at a mean followup of 12.5 months (range 1 to 57). A total of 11 patients (27%) had BXO involvement of the meatus and underwent circumcision combined with meatotomy or meatoplasty. Nine patients (22%) required extensive plastic operation(s) of the penis, including buccal mucosa grafts in 2. CONCLUSIONS: The incidence of BXO in pediatric patients may be higher than previously reported, with the diagnosis rarely made by pediatricians. Our study demonstrates that older patients, those with BXO involvement of the meatus and those with a history of surgery for BXO tend to have a more severe and morbid clinical course.

Balanitis↗
PubMed2005

Early outcome following complete primary repair of bladder exstrophy in the newborn.

PURPOSE: Complete primary repair of bladder exstrophy (CPRE) represents a paradigm shift from the staged approach for surgical management. We present early clinical outcomes in our patients following CPRE. MATERIALS AND METHODS: From 1996 to 2004 all newborns with bladder exstrophy were treated with CPRE within 48 hours of birth. We reviewed parameters including transfusions (packed red blood cells), urethral meatal position, complications, findings on renal ultrasound and renal scan, and post-CPRE procedures and infections. RESULTS: A total of 16 boys and 7 girls were treated with CPRE. Followup ranged from 8 to 96 months. Twelve boys (75%) and 2 girls (29%) received packed red blood cells at CPRE (p = 0.066). The tubularized urethral plate could not be brought to the penile tip, resulting in hypospadias in 9 of 11 boys (82%) with the running suture technique and only 1 of 5 boys (20%) with the interrupted technique (p = 0.036). Of the 23 patients 6 had a total of 8 complications after CPRE. Vesicoureteral reflux was present in 17 of 23 patients. After CPRE a total of 93 endoscopic/surgical procedures (median 4, range 0 to 16 per patient) were performed. Five patients had 1 to 4 episodes of pyelonephritis, 16 of 23 had 1 or more episodes of asymptomatic bacteriuria and 5 had cortical defects on renal scan. CONCLUSIONS: We recommend that urethral closure during CPRE be performed with interrupted suture technique to prevent hypospadias. An aggressive approach should be taken toward reflux in the setting of urinary infection. Consideration should be given for repair of all aspects of the defect during CPRE, including bilateral ureteral reimplantation.

Bladder Exstrophy↗
PubMed2005

Magnetic resonance imaging of pelvic musculoskeletal and genitourinary anatomy in patients before and after complete primary repair of bladder exstrophy.

PURPOSE: We characterize pelvic soft tissue and bony anatomy of patients before and after complete primary repair of exstrophy (CPRE). MATERIALS AND METHODS: We evaluated 15 measurements on pelvic magnetic resonance imaging (MRI) in patients who underwent CPRE without osteotomy at our institution from 1996 to 2004. MRI protocols included axial, sagittal and coronal fast spin echo proton density sequences. Measurements were compared before and after CPRE using a paired t test, and between patients after CPRE, and age and gender matched controls using linear regression adjusting for the matched case-control groups. Patients older than 3 years with continent intervals longer than 3 hours after CPRE were compared to age and gender matched controls using linear regression. RESULTS: A total of 29 MRIs in 18 patients with exstrophy were available for analysis. Median patient age at postoperative MRI was 25 months (range 4 to 36). The configuration of the post-CPRE pelvis was significantly different from that of controls in all parameters measured including wider symphyseal diastasis (34.5 mm vs less than 1 mm) and more obtuse iliac wing (121 degrees vs 98 degrees), puborectalis (94 degrees vs 49 degrees) and ileococcygeus angles (111 degrees vs 98 degrees ). The anatomy of continent patients after CPRE was not significantly different from that of controls in most parameters measured. CONCLUSIONS: Comparison of the pelvic anatomy in patients before and after CPRE suggests that after CPRE patients have parameters that more closely approximate, but are still significantly different, from those of control patients. Patients with greater than 3-hour continent intervals after CPRE have anatomic parameters most similar to those of age matched controls.

Bladder Exstrophy↗
PubMed2005

Bladder growth and development after complete primary repair of bladder exstrophy in the newborn with comparison to staged approach.

PURPOSE: We assessed bladder growth and dynamics following complete primary repair of bladder exstrophy (CPRE) compared to the staged approach. MATERIALS AND METHODS: We reviewed the records of 16 boys and 7 girls who underwent CPRE within 3 days of life from 1996 to 2004 and compared them to the records of 8 boys and 6 girls treated with a staged repair from 1979 to 1996. Screening methods included voiding cystourethrogram, radionuclide cystogram and urodynamic study. We estimated growth curves for bladder capacity following repair in each group, and compared percent predicted bladder capacity (PPBC), compliance and detrusor overactivity between the CPRE and staged repair groups following bladder neck reconstruction. RESULTS: Bladder capacity in the staged repair group was 69.8 ml (95% CI 46.7-104.4) immediately after bladder neck reconstruction and increased by 15.0% per year thereafter (95% CI 6.2-24.5, p = 0.002). In the CPRE group bladder capacity was 29.0 ml (95% CI 21.3-39.5) initially and increased by 28.9% per year thereafter (95% CI 17.4-41.5, p <0.001). PPBC started at 45.6% (95% CI 35.7-55.5) and increased 1.2% per year (95% CI -1.1-3.5, p = 0.29) following repair for all genders and surgery groups. Compliance was 124.4% (95% CI 22.6-310.7, p = 0.01) greater in the CPRE group at all times following repair. Detrusor overactivity was present in 0 of 19 patients in the CPRE group and 6 of 13 (46%) in the staged group (exact p = 0.002). CONCLUSIONS: Within the CPRE group bladder stability was universal, and sphincter electromyography was normal suggesting no neuromuscular compromise of the pelvic floor. At early followup, our results suggest that PPBC is equivalent irrespective of gender or management. Further objective evaluation is needed in both groups.

Bladder Exstrophy↗
PubMed2005

Intermittent testicular torsion: diagnostic features and management outcomes.

PURPOSE: Intermittent testicular torsion (ITT) is a poorly characterized condition but harbors potentially serious implications with regard to testicular viability. We report better characterization of the diagnostic features of ITT. MATERIALS AND METHODS: We performed a retrospective review of all patients 1 to 18 years old seen from 1997 to 2003 at our institution diagnosed with ITT. Patients with acute scrotal pain and spontaneous resolution who underwent bilateral testicular fixation were included in the study. RESULTS: A total of 50 patients meeting the inclusion criteria were identified with mean age at presentation of 12.2 years (range 4 to 17). The mean number of painful episodes before surgery was 4.3 (range 1 to 30). The most common presenting features were severe pain of rapid onset and resolution. Nausea and/or vomiting was reported in a quarter of the patients. Finding of a horizontal lie of the testes on examination was significantly associated (p <0.05) with the existence of the bell-clapper deformity. All patients underwent surgical fixation of the testes. There were no postoperative complications. Of 38 patients (97%) for whom followup was available 37 had complete resolution of symptoms (mean followup 7.9 months). CONCLUSIONS: ITT should be a diagnostic consideration in patients who present with recurrent acute scrotal pain with rapid spontaneous resolution. Recurrent severe pain with rapid onset and resolution seems to be highly characteristic. Horizontal lie on examination is highly correlated with the bell-clapper deformity at surgical exploration. Surgery may be recommended in these patients as it appears to result in pain relief in the majority, is likely to prevent future testicular infarction and is associated with low morbidity.

Adolescent↗
PubMed2005

Testicular hypotrophy does not correlate with grade of adolescent varicocele.

PURPOSE: Testicular hypotrophy is the most widely accepted indication for correcting adolescent varicocele. Previous studies in adolescents have shown a relationship between increasing grade of varicocele and the likelihood of testicular hypotrophy. As this relationship has significant clinical implications, we studied the correlation between grade and testicular volume disproportion in our adolescent varicocele population. MATERIALS AND METHODS: We reviewed the adolescent varicocele database at our institution. A total of 168 patients 8 to 21 years old were studied. We routinely calculated testis volumes using scrotal ultrasound. Testicular disproportion was calculated using the equation [(size of unaffected testis) - (size of affected testis)]/(size of unaffected testis) x 100%. Disproportion was categorized as less than 10%, 10% to 20% and more than 20%. Varicoceles were graded by an attending urologist with the patient standing, using the system of Dubin and Amelar. Analysis of variance and Pearson chi-square indicated no significant differences in volume differential between varicocele grades. RESULTS: Mean +/- SD volume differential was 18% +/- 15% for grade I, 25% +/- 20% for grade II and 19% +/- 14% for grade III. ANOVA revealed no significant difference in mean volume differential between the 3 varicocele grades (p = 0.10). When categorizing patients into 3 levels of volume differential (less than 10%, 10% to 20%, more than 20%) no significant correlation was observed between varicocele and volume differential (p = 0.48, chi-square test). CONCLUSIONS: Grade of varicocele does not correlate with presence or severity of testicular disproportion in adolescent boys with varicocele as measured by scrotal ultrasound.

Adolescent↗
PubMed2005

Growth and stretch response of human exstrophy bladder smooth muscle cells: molecular evidence of normal intrinsic function.

OBJECTIVE: To establish primary cultures of smooth muscle cells (SMC) from human exstrophic bladders (E-SMC), and determine their in vitro growth dynamics and responses to mechanical stretch. MATERIALS AND METHODS: Primary cultures of E-SMC from three patients were established from exstrophic bladder tissue using an explant method. Growth dynamics were assessed using tetrazolium-dye uptake. The DNA synthesis rate in response to cyclic stretch-relaxation was determined with thymidine-incorporation assays. Expression of the SMC mitogen heparin-binding epidermal growth factor-like growth factor (HB-EGF) mRNA in response to mechanical stretch was determined using semiquantitative reverse transcription-polymerase chain reaction. RESULTS: The approximate doubling time of the E-SMC grown in the presence of serum was 4 days, consistent with growth rates of SMC reported previously. E-SMC exposed to stretch had greater DNA synthesis, albeit to a lesser extent than previously seen with non-exstrophic SMC. The expression of HB-EGF was also increased in cells exposed to mechanical stimuli, consistent with our previous finding of stretch-regulated HB-EGF gene expression in bladder SMC. CONCLUSIONS: E-SMC had growth characteristics similar to those previously reported in non-exstrophic cells. E-SMC also had stretch-induced expression of HB-EGF mRNA. These observations provide evidence that despite development in an abnormal defunctionalized state, E-SMC retain the potential for normal growth, and may modulate this response through mechanisms similar to those operating in normal bladder SMC.

Bladder Exstrophy↗
PubMed2004

Laparoscopic and robotic approach to genitourinary anomalies in children.

The evolution of laparoscopic surgery in pediatric urology has been long and slow, but is emerging steadily and seems to be here to stay. This article reviews the basic applications of laparoscopic methods in pediatric urology, including diagnostic and operative procedures. The new horizons of robotic assistance for laparoscopic surgery make highly accurate and efficient reconstructive procedures possible.

Child↗
PubMed2004

Robotically assisted surgery in pediatric urology.

Robotically assisted laparoscopic surgery likely will be a part of pediatric urologic surgery. It will look different than it does now because of technologic and procedural innovations. The inherent value of precise visualization, tissue handling, and reconstruction, coupled with the reduced morbidity of laparoscopic surgery, suggests the potential value of these technologies and methods. Although there is much development to be done, the early results are encouraging. Pediatric urologists specifically, and pediatric surgical practitioners in general, must be involved in the evolution of these techniques and devices, to prevent having to adapt adult surgery-oriented systems to pediatric patients. Pediatric urologists need to be involved in this development actively to guide its course.

Adolescent↗