Taping alone for persistent ventral curvature after urethral plate transection in hypospadias.

INTRODUCTION: Ventral penile curvature is a key factor in determining the surgical approach to proximal hypospadias repair. However, there is limited evidence regarding the efficacy and long-term effects of the procedures used to address curvature. This study aimed to evaluate the effects of urethral plate transection alone with tissue traction therapy on penile curvature in two-stage repair of proximal hypospadias. MATERIAL AND METHODS: This was a prospective study of primary hypospadias patients who underwent a two-stage repair with urethral plate transection as the sole straightening procedure. After stage 1, taping was applied as tissue traction therapy and continued until stage 2. Penile curvature was measured using a goniometer under artificial erection before and immediately after urethral plate transection and during the second stage of repair. The primary focus of this investigation is the angle of curvature after 6-month taping. RESULTS: The study included 46 patients with a median age of 13 months at the start of treatment. The median angle of penile ventral curvature was 70° after degloving, 60° after urethral plate transection, and 0° during the second stage of repair. Full correction of ventral curvature was achieved in 42 patients (91 %). DISCUSSION: This publication is the first of its kind to propose taping as a method for penile traction therapy in hypospadias. The study reveals that penile ventral lengthening can be achieved through tissue traction therapy following UP transection alone. These findings challenge the current consensus that complete straightening of the penis in the first stage is necessary to prevent recurrent curvature and that ventral lengthening is required to correct corporal disproportion. However, further validation and long-term data are needed to definitively confirm the effectiveness of tissue traction therapy after urethral plate transection. CONCLUSIONS: This study demonstrated significant resolution rate of penile ventral curvature in proximal hypospadias following urethral plate transection alone with taping. Long-term follow-up studies are needed to confirm the sustainability of the results through puberty.

An alternative lower tract approach to ectopic duplex system ureteroceles feasible in young children.

INTRODUCTION: The best surgical approach to ectopic ureters and ureteroceles is yet to be determined. The objective of this study is to provide an alternative lower tract surgical approach to ectopic ureters and duplex system ureteroceles that can be safely performed in young children. METHODS: The "in-and-out" bladder approach was performed via an open intravesical incision. The upper and lower pole ureters were mobilized and brought into the bladder. The dilated ureter/ureterocele was cut open, and the distal part was deuroepithelialized. Subsequently, common sheath reimplantation was performed. The ureterocele wall was not involved during the whole procedure. We retrospectively reviewed all patients who underwent surgery for ureteroceles and ectopic ureters between January 1, 2004, and December 31, 2019. Patients with intravesical ureteroceles were excluded. Outcome parameters included the presence of hydronephrosis or reflux, split renal function on DMSA scan, incidence of urinary tract infection, and urinary incontinence. RESULTS: A total of 32 patients with ectopic duplex system ureterocele who underwent the "in-and-out" bladder approach between 2004 and 2019 were included in the retrospective study. The median age at operation was 7.8 months (range: 1.5 months-3.0 years). The median length of follow-up was 6.1 years (range: 1.0 years-14.3 years). Sixteen patients (55%) had ipsilateral vesicoureteral reflux. Five patients postoperatively developed a urinary tract infection within 1-3 years. No patients required further endoscopic treatment or surgeries. During long-term follow-up, two patients (6.3%) had intermittent day wetting at the ages of 4 and 5 years and were managed conservatively. The symptoms of intermittent day wetting subsided during follow-up. CONCLUSIONS: The "in-and-out bladder" approach can be performed in complex duplex system ureteroceles and enables early intervention; it is a single and simple operation with a satisfactory long-term continence rate.

Vesicocutaneous fistula: continent vesicostomy, an easier route for comfortable clean intermittent catheterization.

INTRODUCTION: Clean intermittent catheterization (CIC) through the urethra is the treatment of choice for patients with neurogenic bladder (NGB) or other etiologies that lead to incomplete bladder emptying. However, urethral catheterization can be problematic. Vesicocutaneous fistula (VCF) is a continent catheterizable channel with a low rate of complications. The aim of the study was to evaluate the safety and effectiveness of VCF as a route for CIC. MATERIAL AND METHODS: The authors retrospectively reviewed patients who underwent creation of the VCF for bladder drainage from November 2001 to December 2017. Demographics, indication for VCF, pre-operative and postoperative laboratory/radiologic studies, incidence of febrile urinary tract infection (UTI), and adherence to CIC through VCF were examined. RESULTS: Vesicocutaneous fistula was created in a total of 20 patients (nine males and 11 females; median age, 13.2 years [range: 3.8 months-22.8 years]). The median follow-up time was 30.5 months (range: 5.9 months-16.9 years). The underlying etiologies that resulted in NGB included spina bifida (n = 10), cerebral palsy (n = 2), caudal regression syndrome (n = 2), and others (n = 6). Before creation of the VCF, 13 patients (65%) had either grade ≥3 unilateral or bilateral hydronephrosis as per the Society for Fetal Urology grading system. Thirteen patients (65%) had experienced at least one febrile UTI the year before the creation of the VCF. At the last follow-up, renal function was improved or stabilized in 14 patients (70%). Fifteen patients (75%) had experienced no febrile UTI in the last 1 year. Upper urinary tract dilatation resolved or improved in 10 patients (77%). The VCF continence rate was 88%. In this study, bladder augmentation or the Mitrofanoff procedure was not performed. During maturation, nine patients (45%) had granuloma; five of those cases subsided within 2 years without any intervention. Five patients had VCF stricture, and only one required revision surgery (5%). DISCUSSION: The VCF continence rate was comparable with that of the Mitrofanoff procedure. Adherence to CIC through VCF lowered the rate of UTI and preserved the upper urinary tract. Bladder emptying by CIC through VCF provided the same benefits as those of the Mitrofanoff procedure: extra privacy, social independence, and reduction of parental burden. Although a long maturation stage of 6 months was required, the rate of major complications was low. Most complications were conservatively manageable and seldom required revision surgery. CONCLUSIONS: Vesicocutaneous fistula is a continent catheterizable conduit, an alternative option for bladder management in patients with NGB who cannot undergo urethral CIC smoothly.

Fixation of lung apex in spontaneous pneumothorax is safe and efficient in decrease recurrences.

BACKGROUND: Video-assisted thoracoscopic bullectomy with pleurodesis is widely used to treat spontaneous pneumothorax. However, 1%-3% of patients experience postoperative complications that may require reoperation, such as bleeding or prolonged air leaks, and 3%-7% of patients require a repeat thoracoscopic bullectomy due to recurrence. Therefore, a modified procedure with improved outcomes is required. METHODS: Between January 1, 2011 and December 31, 2015, 196 patients with spontaneous pneumothorax underwent thoracoscopic bullectomy and pleurodesis with or without fixation of the lung apex to the chest wall. In patients in the fixation group, the lung apex was fixed to the chest wall with two non-absorbable sutures after bullectomy and pleurodesis. The treatment of each lung was considered an independent operation in patients with bilateral spontaneous pneumothorax. RESULTS: The patients in each group had comparable backgrounds. In the fixation group, 67 patients underwent 87 operations, four of which (in three patients) led to recurrences (recurrence rate, 4.60%). There were no readmissions or reoperations within 30 days in this group. In the non-fixation group, 128 patients underwent 161 operations, 14 of which (in nine patients) led to recurrences (recurrence rate, 8.7%). In addition, three patients in this group required reoperation and two were readmitted within 30 days. CONCLUSIONS: Modified thoracoscopic bullectomy with fixation of the lung apex is a safe procedure that provides better outcomes with lower complication rates.

An Age-Stratified Longitudinal Study of Primary Spontaneous Pneumothorax.

PURPOSE: The objective of this study was to determine the age-stratified incidence, frequency, and duration of recurrence of primary spontaneous pneumothorax (PSP). METHODS: This study analyzed the epidemiology of PSP among hospitalized patients using the National Health Research Institutes of Taiwan database. The incidence of PSP was determined from a cohort of 19,562 deidentified individuals with PSP between 2001 and 2013. The insurants consisted of 99% of the Taiwan population of about 23 million people. A 5- to 12-year long-term recurrence analysis was based on data from 11,190 patients with PSP between 2001 and 2008. RESULTS: The incidence of PSP in in-patients increased from 5.05 to 7.18/100,000 in a 13-year analysis. The age group at highest risk was 15-22 years with incidence rates >11/100,000 and readmission rates of 17%-31%. About 20% of patients had more than one attack based on long-term follow-ups. About .8% of patients had more than three hospital admissions. Only 3.9% of patients had repeated or recurrent attacks after more than 4 years. All patients who had been admitted on more than four occasions were adolescents, except for four patients who were aged between 20 and 24 years old. CONCLUSIONS: Adolescents with PSP had a higher incidence of attacks and more frequent and longer periods of vulnerability to recurrence. The majority of patients experienced recurrence during the first 4 years after the first attack.

Experience of single-incision laparoscopy in children.

CONTEXT: Laparoscopic surgery is commonly used for the treatment of many pediatric surgical diseases at our department. Single-incision laparoscopic surgery (SILS) is well-known for its cosmetic benefit. We, hereby, present our experience of SILS and evaluate its efficacy. MATERIALS AND METHODS: From July 2012 to June 2014, 78 patients aged less than 18 years who underwent SILS were retrospectively evaluated. There were 44 males and 34 females, with a mean age of 10.3 years. The procedures included appendectomy (n = 64), reduction of intussusception (n = 8), removal of an intestinal foreign body (n = 3), and Meckel's diverticulectomy (n = 3). We compared the patients who underwent SILS with those who underwent conventional laparoscopic surgery (CLS), regarding these procedures. The parameters for analysis included the patient's demographic data, surgical indication, complications, operative time, and length of hospital stay. CONCLUSION: SILS is comparable to CLS regarding two major procedures, namely, appendectomy and reduction of intussusception. There were no significant differences between the two groups regarding the patients' demographic data, complications, and length of hospital stay. According to our experience of SILS, it could be a feasible and safe procedure for the treatment of various pediatric surgical diseases. However, large prospective randomized studies are needed to identify the differences between SIL and CLS.

Chest Wall Constriction after the Nuss Procedure Identified from Chest Radiograph and Multislice Computed Tomography Shortly after Removal of the Bar.

BACKGROUND: This study radiographically examined the changes in the chest walls of patients with pectus excavatum (PE) after Nuss bar removal, to define the deformation caused by the bar and stabilizer. In the first part of the study, we compared the changes in chest radiographs of patients with PE to a preoperation PE control group. In the second part, we used multislice computed tomography (CT) scans to provide three-dimensional reconstructions with which to evaluate the changes to the thoracic wall. METHODS: Part 1 From June 2006 to August 2011, 1,125 patients with PE who had posteroanterior chest radiographs taken before undergoing the Nuss procedure at four hospitals were enrolled as a preoperative control group. At the same time, 203 patients who had the bar removed were enrolled as the study group. The maximum dimensions of the outer boundary of the first to ninth rib pairs (R1-R9, rib pair width), chest height, and chest width were measured. Part 2 Thirty-one consecutive patients with PE (20 males and 11 females) who underwent Nuss bar removal were evaluated 7 to 30 days after operation. During this period, a further 34 patients with PE who had undergone CT imaging before bar insertion were evaluated and compared with the postoperative group. RESULTS: Part 1 The width of the lower ribs (R4-R9) after bar removal was significantly less than in the age-matched controls. The ribs adjacent to the bar (R5-R7) showed the greatest restriction. The width of the upper ribs (R1-R3) 2 to 3 years after bar placement did not differ significantly from the controls. Patients who were operated on after 10 years of age had less of a restrictive effect. Three years of bar placement resulted in more restriction than a 2-year period, particularly in patients younger than 10 years old. Part 2: A significant constriction of the chest wall was observed in 13 patients after removal of the Nuss bar. Constriction at ribs 5 to 8 was found to be present adjacent to the site of bar insertion. However, constriction of the chest wall was found in only 3 of the 34 patients in the preoperative group. The severity of constriction (as graded by the spline model) also increased in the postoperative group. CONCLUSION: The growth of the chest wall was restricted after placement of the Nuss bar for PE correction. Long-term follow-up of chest wall growth is needed to clarify whether such constriction resolves with time.

Postnatal donor lymphocytes enhance prenatally-created chimerism at the risk of graft-versus-host disease.

The major barrier to clinical application of in utero hematopoietic stem cell transplantation is insufficient chimerism for phenotypic correction of target diseases or induction of graft tolerance. Postnatal donor lymphocyte infusion (DLI) may enhance donor cell levels so as to further facilitate tolerance induction. We created murine mixed chimeras in utero. Chimeras with <10% donor cells were subjected to postnatal DLI to evaluate the effects of DLI on chimerism augmentation and skin tolerance induction. Within one day after DLI, recipients experienced a transient peaking of donor chimerism, which could be as high as 20~40%. However, the transient chimerism peaking didn't benefit donor skin survivals despite immediate skin placement after DLI. In case of fruitful DLI, chimerism augmentation was usually observed after a latent period of 2~4 weeks. Otherwise, chimerism would return to around pre-DLI levels by days 7~14. Peripheral chimerism of >3% could be consistently boosted up to >10%, whereas chimerism of <0.2% hardly showed any significant enhancement. As for chimerism levels of 0.2~3%, chimerism augmentation up to >10% succeeded in 3(15%) of 20 recipients. Notably, chimerism augmentation by postnatal DLI was often associated with unexpected death or graft-versus-host disease (GVHD). In conclusion, transient chimerism augmentation by DLI played no role in facilitating graft tolerance. Substantial augmentation by DLI demanded a threshold chimerism level and posed a serious risk of GVHD to the recipients. It raised the concern about using postnatal DLI to broaden therapeutic horizons of in utero hematopoietic stem cell transplantation.

A Cross-Sectional Study of Chest Wall Development in Patients with Pectus Excavatum.

BACKGROUND: We conducted a cross-sectional study to quantify the developmental changes of the thoracic cage in patients with pectus excavatum (PE). METHODS: The preoperative posteroanterior standing chest radiographs (chest PAs) of 1,197 consecutive patients with PE, together with 1,661 age- and sex-matched minor surgery patients, as a control group, who were seen between June 2005 and February 2013, were reviewed. The maximum width of each rib pair and chest height (H) were measured on the chest PA. RESULTS: In the PE group, the normal thoracic contour in younger patients was replaced by a characteristic can-shaped chest wall, which showed protrusion of the upper ribs, an increased H, and a straightened lateral border of the chest cage, as they grew into adulthood. The chest height difference between the PE and control groups increased progressively, from the age of 8 years and most significantly from age 13 to 17 years. No difference was observed in the middle and lower rib widths. Sex did not influence these trends. CONCLUSION: The PE chest wall shows a significant increment in chest height, and upper rib width starts during the period of rapid growth and is maintained into adulthood. The thoracic deformity in patients with PE includes more than just the sternal deformity.

Rapid increase in the height and width of the upper chest in adolescents with primary spontaneous pneumothorax.

BACKGROUND: We determined the chest height in a cohort of patients with primary spontaneous pneumothorax (PSP) who had received chest radiographic examinations prior to the attack. The aim of this study was to determine when their chest height began to change and how this was related to the PSP. METHODS: From June 2009 to February 2012, the chest posteroanterior radiographs of 156 patients with PSP (Group 1) were reviewed. Among another 3134 patients with PSP, we identified 52 patients who had a chest posteroanterior radiograph prior to the attack (Group 2). We also recruited 196 controls for comparison (Group 3). The chest height and chest width at different levels were measured and analyzed. RESULTS: Before 14 years of age, the chest height of patients in Group 2 was no different from that of patients in Group 3. By the age of 14 years, however, the chest height and upper chest width of patients with PSP was significantly higher than that of the normal controls. The difference from normal chest height did not increase at adulthood. CONCLUSION: The rapid increase in chest height and upper chest width is a unique finding in patients with PSP. It might be attributable to the occurrence of PSP. This finding may also help to identify patients who are at risk of PSP.

Recipients with in utero induction of tolerance upregulated MHC class I in the engrafted donor skin.

The alterations in MHC class I expression play a crucial step in immune evasion of cancer or virus-infected cells. This study aimed to examine whether tolerized grafts modified MHC class I expression. FVB/N mice were rendered tolerant of C57BL/6 alloantigens by in utero transplantation of C57BL/6 marrows. Postnatally, engrafted donor skins and leukocytes were examined for their MHC expression by quantitative real-time PCR and flow cytometry. Engrafted donor skins upregulated their MHC class I related gene transcripts after short-term (1~2 weeks) or long-term (>1 month) engraftment. This biological phenomenon was simultaneously associated with upregulation of TAP1 gene transcripts, suggesting an important role of TAP1 in the regulation of MHC class I pathway. The surface MHC class I molecules of H-2K(b) in engrafted donor leukocytes consistently showed overexpression. Conclusively, the induction of allograft tolerance involved biological modifications of donor transplants. The overexpression of MHC class I within engrafted transplants of tolerant mice might be used as the tolerance biomarkers for identifying a state of graft tolerance.

Allogeneic lymphocytes exerted graft-versus-host rather than tolerogenic effects on preimmune fetuses.

BACKGROUND: Among cell suspensions from different origins, lymphocytes were reported to have the superiority of tolerance-conferring capacity in preimmune hosts. However, this belief was derived directly from murine combinations with fewer major histocompatibility complex (MHC) barriers that are exceptional in the clinical arena. Because of the potential for prenatal tolerance induction to facilitate postnatal therapies, it is important to examine the relative merits and hazards of fully MHC-mismatched naïve lymphocytes as the prenatal tolerogenic agent in the preimmune fetus to cross MHC barriers. MATERIALS AND METHODS: In utero injection of C57BL/6 splenic lymphocytes was conducted in gestational day 14 FVB/N fetuses. Then, FVB/N recipients were subjected to the evaluation of hematopoietic chimerism, donor-specific tolerance, and graft-versus-host disease (GVHD). RESULTS: With a dose of ≥ 5 × 10(5) C57BL/6 lymphocytes, the recipients born alive either died unexpectedly by maternal cannibalization or succumbed to GVHD within postnatal 1 mo. GVHD mice showed significant hematopoietic chimerism that was dominated by donor CD3 T cells. It was found that allogeneic lymphocytes could rapidly damage the fetal liver within 5 d after injection. Fetal recipients could survive a dose of ≤ 2 × 10(5) allogeneic lymphocytes beyond 1 mo of age, but at best showed microchimerism that was insufficient to confer donor-specific skin tolerance. CONCLUSIONS: Fully MHC-mismatched lymphocytes injected in utero had lethal graft-versus-host effects, which might rapidly develop within 1 wk after injection in preimmune fetuses. They were incapable of conferring significant hematopoietic chimerism and graft tolerance even at bearable doses.

A cross-sectional study of lung volume development in pectus excavatum patients: estimating the total lung volume from chest computed tomograph using 3-dimensional volumetric reconstruction.

BACKGROUND/PURPOSE: This study quantified the lung volume development of pectus excavatum (PE) patients using chest computed tomography (CT) 3-dimensional volumetric reconstructions. The technique permits current and retrospective analyses of data from different institutions. PATIENTS AND METHODS: We analyzed the records of PE patients who underwent chest CT preoperatively between 2005 and 2009 at 3 institutions. All patients were Chinese. A window of -992 to -198 Hounsfield units was chosen for calculating the CT total lung volume (TLV). The data were compared with the data for 73 microtia and other chest-wall tumor patients studied during the same period as a control group. RESULTS: In total, 377 PE patients with Haller pectus index (PI) of at least 3.2 were identified for this study. Compared with the reported TLV data for 1050 healthy children and our control group, we found little evidence of a decreased TLV in PE patients at any age for either sex. The mean PI did not change significantly between the ages of 3 and 27 years. The PI was inversely correlated with the TLV (P < .001). CONCLUSION: Our cross-sectional study provides evidence that the TLV of PE patients is within the reference range in children and adolescents.

Characterization of tolerance induction through prenatal marrow transplantation: the requirement for a threshold level of chimerism to establish rather than maintain postnatal skin tolerance.

Hematopoietic chimerism resulting from prenatal marrow transplantation does not consistently result in allotolerance for unidentified causes. In a C57BL/6-into-FVB/N murine model, we transplanted T-cell-depleted adult marrow on gestational day 14 to elucidate the immunological significance of chimerism towards postnatal tolerance. Postnatally, chimerism was examined by flow cytometry, and tolerance by skin transplantation and mixed lymphocyte reaction. Regulatory T cells were quantified by FoxP3 expression. Peripheral chimerism linearly related to thymic chimerism, and predicted the degree of graft acceptance with levels >3% at skin placement, yielding consistent skin tolerance. Low- and high-level chimeras had lower intrathymic CD3(high) expression than microchimeras or untransplanted mice. Regardless of the skin tolerance status in mixed chimeras, donor-specific alloreactivity by lymphocytes was suppressed but could be partially restored by exogenous interleukin-2. Recipients that lost peripheral chimerism did not accept donor skin unless prior donor skin had engrafted at sufficient chimerism levels, suggesting that complete tolerance can develop as a consequence of chimerism-related immunosuppression of host lymphocytes and the tolerogenic effects of donor skin. Thus, hematopoietic chimerism exerted immunomodulatory effects on the induction phase of allograft tolerance. Once established, skin tolerance did not fade away along with spontaneous regression of peripheral and tissue chimerism, as well as removal of engrafted donor skin. Neither did it break following in vivo depletion of increased regulatory T cells, and subcutaneous interleukin-2 injection beneath the engrafted donor skin. Those observations indicate that the maintenance of skin tolerance is multifaceted, neither solely dependent upon hematopoietic chimerism and engrafted donor skin nor on the effects of regulatory T cells or clonal anergy. We conclude that hematopoietic chimerism generated by in utero hematopoietic stem cell transplantation is critical to establish rather than maintain postnatal skin tolerance. Therefore, the diminution of hematopoietic chimerism below a threshold level does not nullify an existing tolerance state, but lessens the chance of enabling complete tolerance.

Increase in intrathoracic volume in pectus excavatum patients after the Nuss procedure.

In this study, we present finite element analysis models to calculate the increase in intrathoracic volume of pectus excavatum patients after the Nuss procedure. One virtue of our approach is that the measurement of the intrathoracic volume has no time difference and is not affected by postoperative pain, which cannot be achieved with a 2-year difference between pre- and postoperative pulmonary function testing or any other clinical method. The calculations show that the intrathoracic volume of pectus excavatum patients increased by approximately 2.72-8.88% after the Nuss procedure. The increment curve was patient-dependent, although the increment behavior was similar among the six patients examined. The curve of the increase became flat when the elevating force exceeded 80 N or the displacement of the lower sternal end exceeded 2.6 cm in half of our cases.

The measurement and designation of the pectus bar by computed tomography.

PURPOSE: The length of the bar used for the Nuss procedure is typically determined by measuring the distance between the 2 midaxillary lines and subtracting 2.5 cm. However, this may not be accurate for all patients. Measurements of the chest using computed tomography (CT) were developed for better determination of bar length. METHODS: Seventy-five patients underwent the Nuss procedure between 2005 and 2008. The length and curve of the pectus bar were determined using both the traditional method (TM) and CT. RESULTS: Twelve patients (16%) had length differences (LD) with the methods. The LD and non-LD patients were 18.8 +/- 2.4 and 11.3 +/- 0.6 years old, respectively (P = .005). The proportion of females in the groups was 58.3% (7/12) and 28.6% (18/63), respectively (P = .046). The TM gave a longer bar estimation in all but one patient with a high sternal angulation. Slight bar protrusion was noted in 3 of the 12 patients with LD using TM and 0 of the 9 patients using CT. CONCLUSIONS: Computed tomography measurement is a precise means for determining length, especially in older patients, females with developed breasts, or patients with high sternal angulation. It also allows for better curvature design, preventing multiple intraoperative adjustments.

Analysis of changes to the anterior chest wall after the Nuss procedure-an objective measurement of pectus excavatum.

INTRODUCTION: We report a noninvasive method for recording the deviation of the anterior chest wall (ACW) in patients with pectus excavatum before and after the insertion and removal of a Nuss bar. PATIENTS AND METHOD: All patients undergoing the Nuss procedure at our institutions between June 2008 and February 2009 were enrolled in this study. A thermal plastic strip was used to cast the ACW at the skin level along the area corresponding to the tract of the inserted bar. The height of the ACW was defined as the perpendicular length from the xiphoid process to the transverse line drawn between the 2 midaxillary points. RESULTS: Bar insertion caused a significant increase in ACW height and width. Bar removal reduced the corrective effects in terms of a significant decrease in ACW height; at the same time, an increase in ACW width was noted. CONCLUSION: Feature extraction and analyses of permanent contour casts of the ACW help to understand immediate changes in the ACW after the Nuss procedure and may assist in the design of the bar at insertion. The Nuss bar in situ helped to maintain cosmetic benefits to the ACW.

Costochondral changes in the chest wall after the Nuss procedure: ultrasonographic findings.

PURPOSE: The Nuss procedure is one of the most popular surgeries for correcting pectus excavatum. However, little is known regarding stress and strain on the deformed ribs after inserting the pectus bar. We used ultrasonography to investigate costochondral changes before and after the Nuss procedure. METHODS: Ninety-five patients underwent the Nuss procedure between July 2007 and February 2008 at 2 institutions. Chest ultrasonography, specifically of the bones and cartilage, was performed 1 day before and 1 week after the operation. RESULTS: Postoperatively, all patients showed various degrees of deformation from the second to sixth cartilages bilaterally. The cartilages were not fractured. Of these patients, 28 (29.5%) had significant changes, including acute angulation of the costochondral junction and rib fractures near the pectus bar. These changes were associated with increased age (P < .01) and the degree of postoperative sternum elevation (P < .01). The pectus index and sex were not significant predictors of rib damage. CONCLUSIONS: The Nuss procedure created significant stress and strain over the deformed cartilages. Approximately 29% of the patients showed localized, self-limited costochondral changes via chest ultrasonography.

Prenatal tolerance induction: relationship between cell dose, marrow T-cells, chimerism, and tolerance.

It was reported that the dose of self-antigens can determine the consequence of deletional tolerance and donor T cells are critical for tolerance induction in mixed chimeras. This study aimed at assessing the effect of cell doses and marrow T cells on engraftment and tolerance induction after prenatal bone marrow transplantation. Intraperitoneal cell transplantation was performed in FVB/N (H-2K(q)) mice at gestational day 14 with escalating doses of adult C57BL/6 (H-2K(b)) marrows. Peripheral chimerism was examined postnatally by flow cytometry and tolerance was tested by skin transplantation. Transplantation of light-density marrow cells showed a dose response. High-level chimerism emerged with a threshold dose of 5.0 x 10(6) and host leukocytes could be nearly replaced at a dose of 7.5-10.0 x 10(6). High-dose transplants conferred a steady long-lasting donor-specific tolerance but were accompanied by >50% incidence of graft-versus-host disease. Depletion of marrow T cells lessened graft-versus-host disease to the detriment of engraftment. With low-level chimerism, tolerance was a graded phenomenon dependent upon the level of chimerism. Durable chimerism within 6 months required a threshold of > or = 2% chimerism at 1 month of age and predicted a 50% chance of long-term tolerance, whereas transient chimerism (<2%) only caused hyporesponsiveness to the donor. Tolerance induction did not succeed without peripheral chimerism even if a large amount of injected donor cells persisted in the peritoneum. Neither did an increase in cell doses or donor T-cell contents benefit skin graft survivals unless it had substantially improved peripheral chimerism. Thus, peripheral chimerism level can be a simple and straightforward test to predict the degree of prenatal immune tolerance.

Preliminary analysis of the forces on the thoracic cage of patients with pectus excavatum after the Nuss procedure.

BACKGROUND: The Nuss procedure corrects pectus excavatum using a pre-bent bar that generates stress on the chest wall. To investigate the biomechanical effects after the Nuss procedure, we designed a three-dimensional finite element analysis model to analyze the distribution of stress and strain induced in the chest wall. METHODS: Three patients with pectus excavatum aged 8, 7, and 7 years, were enrolled in this study. The greatest upward displacements of their sternums after the operation were measured from computed tomography images and chest X-ray films. Based on these displacements, we constructed three finite element analysis models for analyzing biomechanical changes in the thoracic cage after the Nuss procedure. FINDINGS: The simulation results indicated that greatest strain occurred at the third through seventh cartilages, especially where they join the sternum and ribs. A high bilateral stress distribution was also found over the backs of the third to the seventh ribs near the vertebral column. INTERPRETATION: The stress and strain induced by the Nuss procedure can be analyzed using our finite element analysis model. Although the stress and strain may have some influence on chest and spine development, a more detailed finite element analysis model is recommended for future study to improve the accuracy of our simulation results.