Real-time quantification of bowel perfusion using Laparoscopic Laser Speckle Contrast Imaging (LSCI) in a porcine model

BACKGROUND/PURPOSE

Real-time quantification of tissue perfusion can improve intraoperative surgical decision making. Here we demonstrate the utility of Laser Speckle Contrast Imaging as an intra-operative tool that quantifies real-time regional differences in intestinal perfusion and distinguishes ischemic changes resulting from arterial/venous obstruction.

METHODS

Porcine models (n = 3) consisted of selectively devascularized small bowel loops that were used to measure the perfusion responses under conditions of control/no vascular occlusion, arterial inflow occlusion, and venous outflow occlusion using laser speckle imaging and indocyanine green fluoroscopy. Laser Speckle was also used to assess perfusion differences between small bowel antimesenteric-antimesenteric and mesenteric-mesenteric anastomoses. Perfusion quantification was measured in relative perfusion units calculated from the laser speckle perfusion heatmap.

RESULTS

Laser Speckle distinguished between visually identified perfused, watershed, and ischemic intestinal segments with both color heatmap and quantification (p < .00001). It detected a continuous gradient of relative intestinal perfusion as a function of distance from the stapled ischemic bowel edge. Strong positive linear correlation between relative perfusion units and changes in mean arterial pressure resulting from both arterial (R2 = .96/.79) and venous pressure changes (R2 = .86/.96) was observed. Furthermore, Laser Speckle showed that the antimesenteric anastomosis had a higher perfusion than mesenteric anastomosis (p < 0.01).

CONCLUSIONS

Laser Speckle Contrast Imaging provides objective, quantifiable tissue perfusion information in both color heatmap and relative numerical units. Laser Speckle can detect spatial/temporal differences in perfusion between antimesenteric and mesenteric borders of a bowel segment and precisely detect perfusion changes induced by progressive arterial/venous occlusions in real-time.

Laser speckle contrast imaging compared with indocyanine green in renal perfusion of a porcine model

Background

When viewed under near-infrared light, indocyanine green (ICG) signal for kidney perfusion can be utilized in partial nephrectomy. Laser speckle contrast imaging (LSCI) uses coherent light to detect perfusion during real-time laparoscopic surgery.

Materials and methods

Laser speckle contrast imaging or ActivSight, an imaging sensor adapter, was used during laparoscopy of an anesthetized porcine kidney model. ActivSight's "perfusion mode" and "quantification mode" displayed the blood flow as a heatmap and numerical signal intensity, respectively.

Results

After the upper segmental renal artery was clamped, ICG was seen in the lower pole, and LSCI showed low unit (dark color) quantification and perfusion in the upper pole. Indocyanine green was retained in the lower pole after the upper segmental artery was unclamped, and LSCI perfusion was demonstrated in the entire kidney.

Conclusions

Laser speckle contrast imaging is a dye-free, repeatable, real-time adjunct for renal parenchymal perfusion assessment applicable to minimally invasive renal surgery to complement the technology of ICG near-infrared fluorescence and advance digital surgery.

Real-time quantification of intestinal perfusion and arterial versus venous occlusion using laser speckle contrast imaging in porcine model

PURPOSE

Real-time intraoperative perfusion assessment may reduce anastomotic leaks. Laser speckle contrast imaging (LSCI) provides dye-free visualization of perfusion by capturing coherent laser light scatter from red blood cells and displays perfusion as a colormap. Herein, we report a novel method to precisely quantify intestinal perfusion using LSCI.

METHODS

ActivSight™ is an FDA-cleared multi-modal visualization system that can detect and display perfusion via both indocyanine green imaging (ICG) and LSCI in minimally invasive surgery. An experimental prototype LSCI perfusion quantification algorithm was evaluated in porcine models. Porcine small bowel was selectively devascularized to create regions of perfused/watershed/ischemic bowel, and progressive aortic inflow/portal vein outflow clamping was performed to study arterial vs. venous ischemia. Continuous arterial pressure was monitored via femoral line.

RESULTS

LSCI perfusion colormaps and quantification distinguished between perfused, watershed, and ischemic bowel in all vascular control settings: no vascular occlusion (p < 0.001), aortic occlusion (p < 0.001), and portal venous occlusion (p < 0.001). LSCI quantification demonstrated similar levels of ischemia induced both by states of arterial inflow and venous outflow occlusion. LSCI-quantified perfusion values correlated positively with higher mean arterial pressure and with increasing distance from ischemic bowel.

CONCLUSION

LSCI relative perfusion quantification may provide more objective real-time assessment of intestinal perfusion compared to conventional naked eye assessment by quantifying currently subjective gradients of bowel ischemia and identifying both arterial/venous etiologies of ischemia.

Feasibility and comparison of laparoscopic laser speckle contrast imaging to near-infrared display of indocyanine green in intraoperative tissue blood flow/tissue perfusion in preclinical porcine models

OBJECTIVE

To determine if laser speckle contrast imaging (LSCI) mitigates variations and subjectivity in the use and interpretation of indocyanine green (ICG) fluorescence in the current visualization paradigm of real-time intraoperative tissue blood flow/perfusion in clinically relevant scenarios.

METHODS

De novo laparoscopic imaging form-factor detecting real-time blood flow using LSCI and blood volume by near-infrared fluorescence (NIRF) of ICG was compared to ICG NIRF alone, for dye-less real-time visualization of tissue blood flow/perfusion. Experienced surgeons examined LSCI and ICG in segmentally devascularized intestine, partial gastrectomy, and the renal hilum across six porcine models. Precision and accuracy of identifying demarcating lines of ischemia/perfusion in tissues were determined in blinded subjects with varying levels of surgical experience.

RESULTS

Unlike ICG, LSCI perfusion detection was real time (latency < 150 ms: p < 0.01), repeatable and on-demand without fluorophore injection. Operating surgeons (n = 6) precisely and accurately identified concordant demarcating lines in white light, LSCI, and ICG modes immediately. Blinded subjects (n = 21) demonstrated similar spatial-temporal precision and accuracy with all three modes ≤ 2 min after ICG injection, and discordance in ICG mode at ≥ 5 min in devascularized small intestine (p < 0.0001) and in partial gastrectomy (p < 0.0001).

CONCLUSIONS

Combining LSCI for near real-time blood flow detection with ICG fluorescence for blood volume detection significantly improves precision and accuracy of perfusion detection in tissue locations over time, in real time, and repeatably on-demand than ICG alone.

Are Current Technical Exclusion Criteria for Clinical Trials of Magnetic Resonance-Guided High-Intensity Focused Ultrasound Too Restrictive?: Early Experiences at a Pediatric Hospital

Certain technical criteria must be met to ensure the treatment safety of magnetic resonance-guided high-intensity focused ultrasound. We retrospectively reviewed how our enrollment criteria were applied from 2014 to 2017 in a clinical trial of magnetic resonance-guided high-intensity focused ultrasound ablation of recurrent malignant and locally aggressive benign solid tumors. Among the 36 screened patients between 2014 and 2017, more than one-third were excluded for technical exclusion criteria such as the anatomic location and proximity to prosthetics. Overall, patients were difficult to accrue for this trial, given the incidence of these tumors. To increase potential accrual, screening exclusion criteria could be more generalized and centered on the ability to achieve an acceptable treatment safety margin, rather than specifically excluding on the basis of general anatomic areas.

ZEB2, a master regulator of the epithelial-mesenchymal transition, mediates trophoblast differentiation

STUDY QUESTION

Does the upregulation of the zinc finger E-box binding homeobox 2 (ZEB2) transcription factor in human trophoblast cells lead to alterations in gene expression consistent with an epithelial-mesenchymal transition (EMT) and a consequent increase in invasiveness?

SUMMARY ANSWER

Overexpression of ZEB2 results in an epithelial-mesenchymal shift in gene expression accompanied by a substantial increase in the invasive capacity of human trophoblast cells.

WHAT IS KNOWN ALREADY

In-vivo results have shown that cytotrophoblast differentiation into extravillous trophoblast involves an epithelial-mesenchymal transition. The only EMT master regulatory factor which shows changes consistent with extravillous trophoblast EMT status and invasive capacity is the ZEB2 transcription factor.

STUDY DESIGN, SIZE, DURATION

This study is a mechanistic investigation of the role of ZEB2 in trophoblast differentiation. We generated stable ZEB2 overexpression clones using the epithelial BeWo and JEG3 choriocarcinoma lines. Using these clones, we investigated the effects of ZEB2 overexpression on the expression of EMT-associated genes and proteins, cell morphology and invasive capability.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We used lentiviral transduction to overexpress ZEB2 in BeWo and JEG3 cells. Stable clones were selected based on ZEB2 expression and morphology. A PCR array of EMT-associated genes was used to probe gene expression. Protein measurements were performed by western blotting. Gain-of-function was assessed by quantitatively measuring cell invasion rates using a Transwell assay, a 3D bioprinted placenta model and the xCelligenceTM platform.

MAIN RESULTS AND THE ROLE OF CHANCE

The four selected clones (2 × BeWo, 2 × JEG3, based on ZEB2 expression and morphology) all showed gene expression changes indicative of an EMT. The two clones (1 × BeWo, 1 × JEG3) showing >40-fold increase in ZEB2 expression also displayed increased ZEB2 protein; the others, with increases in ZEB2 expression <14-fold did not. The two high ZEB2-expressing clones demonstrated robust increases in invasive capacity, as assessed by three types of invasion assay. These data identify ZEB2-mediated transcription as a key mechanism transforming the epithelial-like trophoblast into cells with a mesenchymal, invasive phenotype.

LARGE SCALE DATA

PCR array data have been deposited in the GEO database under accession number GSE116532.

LIMITATIONS, REASONS FOR CAUTION

These are in-vitro studies using choriocarcinoma cells and so the results should be interpreted in view of these limitations. Nevertheless, the data are consistent with in-vivo findings and are replicated in two different cell lines.

WIDER IMPLICATIONS OF THE FINDINGS

The combination of these data with the in-vivo findings clearly identify ZEB2-mediated EMT as the mechanism for cytotrophoblast differentiation into extravillous trophoblast. Having characterized these cellular mechanisms, it will now be possible to identify the intracellular and extracellular regulatory components which control ZEB2 and trophoblast differentiation. It will also be possible to identify the aberrant factors which alter differentiation in invasive pathologies such as preeclampsia and abnormally invasive placenta (AKA accreta, increta, percreta).

STUDY FUNDING AND COMPETING INTEREST(s)

Funding was provided by the Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine and Surgery at Hackensack Meridian Health, Hackensack, NJ. The 3D bioprinted placental model work done in Drs Kim and Fisher's labs was supported by the Children's National Medical Center. The xCELLigence work done in Dr Birge's lab was supported by NIH CA165077. The authors declare no competing interests.

Mechanical fractionation of tissues using microsecond-long HIFU pulses on a clinical MR-HIFU system

PURPOSE

High intensity focussed ultrasound (HIFU) can non-invasively treat tumours with minimal or no damage to intervening tissues. While continuous-wave HIFU thermally ablates target tissue, the effect of hundreds of microsecond-long pulsed sonications is examined in this work. The objective of this study was to characterise sonication parameter-dependent thermomechanical bioeffects to provide the foundation for future preclinical studies and facilitate clinical translation.

METHODS AND MATERIALS

Acoustic power, number of cycles/pulse, sonication time and pulse repetition frequency (PRF) were varied on a clinical magnetic resonance imaging (MRI)-guided HIFU (MR-HIFU) system. Ex vivo porcine liver, kidney and cardiac muscle tissue samples were sonicated (3 × 3 grid pattern, 1 mm spacing). Temperature, thermal dose and T2 relaxation times were quantified using MRI. Lesions were histologically analysed using H&E and vimentin stains for lesion structure and viability.

RESULTS

Thermomechanical HIFU bioeffects produced distinct types of fractionated tissue lesions: solid/thermal, paste-like and vacuolated. Sonications at 20 or 60 Hz PRF generated substantial tissue damage beyond the focal region, with reduced viability on vimentin staining, whereas H&E staining indicated intact tissue. Same sonication parameters produced dissimilar lesions in different tissue types, while significant differences in temperature, thermal dose and T2 were observed between the parameter sets.

CONCLUSION

Clinical MR-HIFU system was utilised to generate distinct types of lesions and to produce targeted thermomechanical bioeffects in ex vivo tissues. The results guide HIFU research on thermomechanical tissue bioeffects, inform future studies and advice sonication parameter selection for direct tumour ablation or immunomodulation using a clinical MR-HIFU system.

Development and Feasibility of a Robotic Laparoscopic Clipping Tool for Wound Closure and Anastomosis

This paper reports the design, development, and initial evaluation of a robotic laparoscopic clipping tool for single manipulator wound closure and anastomosis (tubular reconnection). The tool deploys biodegradable clips and clasps with the goal of (i) integrating grasping and suturing into a single device for single hand or manipulator use, (ii) applying the equivalent of interrupted sutures without the need of managing suture thread, and (iii) allowing for full six degrees-of-freedom (DOFs) laparoscopic control when mounted on a robot arm. The specifications, workflow, and detailed design of the robotic laparoscopic tool and injection molded bio-absorbable T shaped clip and locking clasp are reported. The clipping tool integrates forceps to grab and stabilize tissue and a clip and clasp applier to approximate and fixate the tissue. A curved needle is advanced on a circular needle path and picks up and drags clips through tissue. The clip is then tightened through the tissue and a clasp is clamped around the clip, before the clip is released from the needle. Results of several bench test runs of the tool show: (a) repeatable circular needle drive, (b) successful pick-up and deployment of clips, (c) successful shear of the clip to release the clip from the needle, and (d) closure of clasp on clip with an average of 2.0 N holding force. These data indicate that the robotic laparoscopic clipping tool could be used for laparoscopic wound closure and anastomosis.

Supervised autonomous robotic soft tissue surgery

The current paradigm of robot-assisted surgeries (RASs) depends entirely on an individual surgeon's manual capability. Autonomous robotic surgery-removing the surgeon's hands-promises enhanced efficacy, safety, and improved access to optimized surgical techniques. Surgeries involving soft tissue have not been performed autonomously because of technological limitations, including lack of vision systems that can distinguish and track the target tissues in dynamic surgical environments and lack of intelligent algorithms that can execute complex surgical tasks. We demonstrate in vivo supervised autonomous soft tissue surgery in an open surgical setting, enabled by a plenoptic three-dimensional and near-infrared fluorescent (NIRF) imaging system and an autonomous suturing algorithm. Inspired by the best human surgical practices, a computer program generates a plan to complete complex surgical tasks on deformable soft tissue, such as suturing and intestinal anastomosis. We compared metrics of anastomosis-including the consistency of suturing informed by the average suture spacing, the pressure at which the anastomosis leaked, the number of mistakes that required removing the needle from the tissue, completion time, and lumen reduction in intestinal anastomoses-between our supervised autonomous system, manual laparoscopic surgery, and clinically used RAS approaches. Despite dynamic scene changes and tissue movement during surgery, we demonstrate that the outcome of supervised autonomous procedures is superior to surgery performed by expert surgeons and RAS techniques in ex vivo porcine tissues and in living pigs. These results demonstrate the potential for autonomous robots to improve the efficacy, consistency, functional outcome, and accessibility of surgical techniques.

Phase 1 trial of lyso-thermosensitive liposomal doxorubicin (LTLD) and magnetic resonance guided high intensity focused ultrasound (MR-HIFU) for pediatric refractory solid tumors

TPS10579

Background: Prognosis for children and young adults with refractory solid tumors remains unacceptably poor. Current approaches have reached the limits of maximal dose intensification, and the acute and late side effects of therapy are substantial. MR-HIFU is an innovative therapy that uses an external applicator to focus ultrasound energy inside a tumor non-invasively and without radiation. The resulting heating is precisely controlled and accurately targeted with the aid of MR thermometry and anatomic imaging. The flexibility and control over local heating by MR-HIFU provide an ideal system to be used with LTLD, a novel formulation of liposomal doxorubicin with the unique property of rapid heat-activated release of doxorubicin, an active agent in most pediatric solid tumors. The potential synergistic effects include enhanced permeability of the tumor vasculature, enhanced extravasation of the drug and subsequent high local concentrations of doxorubicin in the targeted tumor, inhibition of DNA repair, and stimulation of immune responses. Methods: This is the first pediatric trial of LTLD with MR-HIFU in refractory solid tumors (NCT02536183). Part A is a phase 1 dose escalation study to determine the maximum tolerated dose (MTD) or recommended phase 2 dose (RP2D) of LTLD combined with MR-HIFU ablation in children. Part B combines LTLD at the MTD/RP2D with MR-HIFU induced mild hyperthermia (MHT) in an expanded cohort. Patients ≤21 (Part A) and ≤30 (Part B) years of age with refractory solid tumors at sites accessible to MR-HIFU, adequate organ function including cardiac function, and prior anthracycline dose of ≤ 450 mg/m2 are eligible. LTLD is administered intravenously over 30 min followed immediately by MR-HIFU on day 1 of a 21-day cycle. Patients can receive a maximum of 6 cycles (or lifetime of 600 mg/m2 of cumulative anthracycline) provided treatment is tolerated and have at least stable disease. Secondary objectives evaluate changes in quality of life and pharmacodynamic immune markers in children treated with LTLD and MR-HIFU. Clinical trial information: NCT02536183.

Technical aspects of osteoid osteoma ablation in children using MR-guided high intensity focussed ultrasound

BACKGROUND

Osteoid osteoma (OO) is a painful bone tumour occurring in children and young adults. Magnetic resonance imaging-guided high intensity focussed ultrasound (MR-HIFU) allows non-invasive treatment without ionising radiation exposure, in contrast to the current standard of care treatment with radiofrequency ablation (RFA). This report describes technical aspects of MR-HIFU ablation in the first 8 paediatric OO patients treated in a safety and feasibility clinical trial (total enrolment of up to 12 patients).

MATERIALS AND METHODS

OO lesions and adjacent periosteum were treated with MR-HIFU ablation in 5-20 sonications (sonication duration = 16-48 s, frequency = 1.2 MHz, acoustic power = 20-160 W). Detailed treatment workflow, patient positioning and coupling strategies, as well as temperature and tissue perfusion changes were summarised and correlated.

RESULTS

MR-HIFU ablation was feasible in all eight cases. Ultrasound standoff pads were shaped to conform to extremity contours providing acoustic coupling and aided patient positioning. The energy delivered was 10 ± 7 kJ per treatment, raising maximum temperature to 83 ± 3 °C. Post ablation contrast-enhanced MRI showed ablated volumes ranging 0.46-19.4 cm³ extending further into bone (7 ± 4 mm) than into soft tissue (4 ± 6 mm, p = 0.01, Mann-Whitney). Treatment time ranged 30-86 min for sonication and 160 ± 40 min for anaesthesia. No serious treatment-related adverse events were observed. Complete pain relief with no medication occurred in 7/8 patients within 28 days following treatment.

CONCLUSIONS

MR-HIFU ablation of painful OO appears technically feasible in children and it may become a non-invasive and radiation-free alternative for painful OO. Therapy success, efficiency, and applicability may be improved through specialised equipment designed more specifically for extremity bone ablation.

Boiling histotripsy lesion characterization on a clinical magnetic resonance imaging-guided high intensity focused ultrasound system

Purpose

High intensity focused ultrasound (HIFU) is a non-invasive therapeutic technique that can thermally ablate tumors. Boiling histotripsy (BH) is a HIFU approach that can emulsify tissue in a few milliseconds. Lesion volume and temperature effects for different BH sonication parameters are currently not well characterized. In this work, lesion volume, temperature distribution, and area of lethal thermal dose were characterized for varying BH sonication parameters in tissue-mimicking phantoms (TMP) and demonstrated in ex vivo tissues.

Methods

The following BH sonication parameters were varied using a clinical MR-HIFU system (Sonalleve V2, Philips, Vantaa, Finland): acoustic power, number of cycles/pulse, total sonication time, and pulse repetition frequency (PRF). A 3×3×3 pattern was sonicated inside TMP’s and ex vivo tissues. Post sonication, lesion volumes were quantified using 3D ultrasonography and temperature and thermal dose distributions were analyzed offline. Ex vivo tissues were sectioned and stained with H&E post sonication to assess tissue damage.

Results

Significant increase in lesion volume was observed while increasing the number of cycles/pulse and PRF. Other sonication parameters had no significant effect on lesion volume. Temperature full width at half maximum at the end of sonication increased significantly with all parameters except total sonication time. Positive correlation was also found between lethal thermal dose and lesion volume for all parameters except number of cycles/pulse. Gross pathology of ex vivo tissues post sonication displayed either completely or partially damaged tissue at the focal region. Surrounding tissues presented sharp boundaries, with little or no structural damage to adjacent critical structures such as bile duct and nerves.

Conclusion

Our characterization of effects of HIFU sonication parameters on the resulting lesion demonstrates the ability to control lesion morphologic and thermal characteristics with a clinical MR-HIFU system in TMP’s and ex vivo tissues. We demonstrate that this system can produce spatially precise lesions in both phantoms and ex vivo tissues. The results provide guidance on a preliminary set of BH sonication parameters for this system, with a potential to facilitate BH translation to the clinic.

Biocompatible Near-Infrared Three-Dimensional Tracking System

A fundamental challenge in soft-tissue surgery is that target tissue moves and deforms, becomes occluded by blood or other tissue, and is difficult to differentiate from surrounding tissue. We developed small biocompatible near-infrared fluorescent (NIRF) markers with a novel fused plenoptic and NIR camera tracking system, enabling three-dimensional tracking of tools and target tissue while overcoming blood and tissue occlusion in the uncontrolled, rapidly changing surgical environment. In this work, we present the tracking system and marker design and compare tracking accuracies to standard optical tracking methods using robotic experiments. At speeds of 1 mm/s, we observe tracking accuracies of 1.61 mm, degrading only to 1.71 mm when the markers are covered in blood and tissue.

"Just-In-Time" Simulation Training Using 3-D Printed Cardiac Models After Congenital Cardiac Surgery

BACKGROUND

High-fidelity simulation using patient-specific three-dimensional (3D) models may be effective in facilitating pediatric cardiac intensive care unit (PCICU) provider training for clinical management of congenital cardiac surgery patients.

METHODS

The 3D-printed heart models were rendered from preoperative cross-sectional cardiac imaging for 10 patients undergoing congenital cardiac surgery. Immediately following surgical repair, a congenital cardiac surgeon and an intensive care physician conducted a simulation training session regarding postoperative care utilizing the patient-specific 3D model for the PCICU team. After the simulation, Likert-type 0 to 10 scale questionnaire assessed participant perception of impact of the training session.

RESULTS

Seventy clinicians participated in training sessions, including 22 physicians, 38 nurses, and 10 ancillary care providers. Average response to whether 3D models were more helpful than standard hand off was 8.4 of 10. Questions regarding enhancement of understanding and clinical ability received average responses of 9.0 or greater, and 90% of participants scored 8 of 10 or higher. Nurses scored significantly higher than other clinicians on self-reported familiarity with the surgery (7.1 vs. 5.8; P = .04), clinical management ability (8.6 vs. 7.7; P = .02), and ability enhancement (9.5 vs. 8.7; P = .02). Compared to physicians, nurses and ancillary providers were more likely to consider 3D models more helpful than standard hand off (8.7 vs. 7.7; P = .05). Higher case complexity predicted greater enhancement of understanding of surgery (P = .04).

CONCLUSION

The 3D heart models can be used to enhance congenital cardiac critical care via simulation training of multidisciplinary intensive care teams. Benefit may be dependent on provider type and case complexity.

Plenoptic Cameras in Surgical Robotics: Calibration, Registration, and Evaluation

Three-dimensional sensing of changing surgical scenes would improve the function of surgical robots. This paper explores the requirements and utility of a new type of depth sensor, the plenoptic camera, for surgical robots. We present a metric calibration procedure for the plenoptic camera and the registration of its coordinate frame to the robot (hand-eye calibration). We also demonstrate the utility in robotic needle insertion and application of sutures in phantoms. The metric calibration accuracy is reported as 1.14 ± 0.80 mm for the plenoptic camera and 1.57 ± 0.90 mm for hand-eye calibration. The accuracy of needle insertion task is 1.79 ± 0.35 mm for the entire robotic system. Additionally, the accuracy of suture placement with the presented system is reported at 1.80 ± 0.43 mm. Finally, we report consistent suture spacing with only 0.11 mm standard deviation between inter-suture distances. The measured accuracy of less than 2 mm with consistent suture spacing is a promising result to provide repeatable leak-free suturing with a robotic tool and a plenoptic depth imager.

Pediatric tracheomalacia

Tracheomalacia (TM) is defined as an increased collapsibility of the trachea due to structural anomalies of the tracheal cartilage and/or posterior membrane. Tracheomalacia has a wide range of etiologies but is most commonly present in children born with esophageal atresia and tracheal esophageal fistula. Clinical symptoms can range from minor expiratory stridor with typical barking cough to severe respiratory distress episodes to acute life-threatening events (ALTE). Although the majority of children have mild-to-moderate symptoms and will not need surgical intervention, some will need life-changing surgical treatment. This article examines the published pediatric literature on TM, discusses the details of clinical presentation, evaluation, diagnosis, and a variety of treatments.

Multispectral tissue characterization for intestinal anastomosis optimization

Intestinal anastomosis is a surgical procedure that restores bowel continuity after surgical resection to treat intestinal malignancy, inflammation, or obstruction. Despite the routine nature of intestinal anastomosis procedures, the rate of complications is high. Standard visual inspection cannot distinguish the tissue subsurface and small changes in spectral characteristics of the tissue, so existing tissue anastomosis techniques that rely on human vision to guide suturing could lead to problems such as bleeding and leakage from suturing sites. We present a proof-of-concept study using a portable multispectral imaging (MSI) platform for tissue characterization and preoperative surgical planning in intestinal anastomosis. The platform is composed of a fiber ring light-guided MSI system coupled with polarizers and image analysis software. The system is tested on ex vivo porcine intestine tissue, and we demonstrate the feasibility of identifying optimal regions for suture placement.

Smart tissue anastomosis robot (STAR): a vision-guided robotics system for laparoscopic suturing

This paper introduces the smart tissue anastomosis robot (STAR). Currently, the STAR is a proof-of-concept for a vision-guided robotic system featuring an actuated laparoscopic suturing tool capable of executing running sutures from image-based commands. The STAR tool is designed around a commercially available laparoscopic suturing tool that is attached to a custom-made motor stage and the STAR supervisory control architecture that enables a surgeon to select and track incisions and the placement of stitches. The STAR supervisory-control interface provides two modes: A manual mode that enables a surgeon to specify the placement of each stitch and an automatic mode that automatically computes equally-spaced stitches based on an incision contour. Our experiments on planar phantoms demonstrate that the STAR in either mode is more accurate, up to four times more consistent and five times faster than surgeons using state-of-the-art robotic surgical system, four times faster than surgeons using manual Endo360(°)®, and nine times faster than surgeons using manual laparoscopic tools.

Kif7 regulates Gli2 through Sufu-dependent and -independent functions during skin development and tumorigenesis

Abnormal activation of Hedgehog (Hh) signaling leads to basal cell carcinoma (BCC) of the skin, the most common human cancer. Gli2, the major transcriptional activator of Hh signaling, is essential for hair follicle development and its overexpression in epidermis induces BCC formation and maintains tumor growth. Despite its importance in skin development and tumorigenesis, little is known about the molecular regulation of Gli2. Sufu and Kif7 are two evolutionarily conserved regulators of Gli transcription factors. Here, we show that Sufu and Kif7 regulate Gli2 through distinct mechanisms in keratinocytes. Sufu restricts the activity of Gli2 through cytoplasmic sequestration. Kif7 possesses Sufu-dependent and -independent regulatory functions in Hh signaling: while it promotes Hh pathway activity through the dissociation of Sufu-Gli2 complex, it also contributes to the repression of Hh target genes in the absence of Sufu. Deletion of both Sufu and Kif7 in embryonic skin leads to complete loss of follicular fate. Importantly, although inactivation of Sufu or Kif7 alone in adult epidermis cannot promote BCC formation, their simultaneous deletion induces BCC. These studies establish Sufu and Kif7 as crucial components in the regulation of Gli2 localization and activity, and illustrate their overlapping functions in skin development and tumor suppression.

An innovative method of pediatric chest wall reconstruction using Surgisis and swinging rib technique

PURPOSE

Herein, we describe a new surgical approach for chest wall reconstruction using a native supporting rib and Surgisis.

METHODS

A retrospective review of 3 cases from 2 tertiary pediatric health care centers presenting with chest wall defects in the neonatal period was performed. Perioperative data were collected.

RESULTS

Two chest wall deformities were diagnosed at birth (Poland syndrome and cleft sternum). One patient was diagnosed prenatally with a mediastinal mass. The first infant had absent ribs 2 through 9. He underwent chest wall reconstruction at 4 weeks of life because of difficulty weaning from ventilation related to paradoxical breathing. The hamartoma of the second asymptomatic patient was removed at 6 weeks. The third patient's V-shaped sternal defect encompassed through the upper two thirds of the sternum and was repaired at 6 months of age with intraoperative transesophageal echocardiogram monitoring. In all cases, Surgisis (collagen matrix) was used as an onlay patch. In 2 cases, a swinging rib acted supportive. Neither patient had intraoperative complications.

CONCLUSION

Surgisis is useful in pediatric chest wall reconstruction, particularly in combination with swinging ribs. The capacity for adaptation to the child's growth of this approach is crucial. Short-term safety is shown, but long-term assessment is required.

Generation of normative pediatric skull models for use in cranial vault remodeling procedures

PURPOSE

While the goal of craniofacial reconstruction surgery is to restore the cranial head shape as much towards normal as possible, for the individual patient, there is, in fact, no normal three-dimensional (3D) model to act as a guide. In this project, we generated a library of normative pediatric skulls from which a guiding template could be fabricated for a more standardized, objective and precise correction of craniosynostosis.

METHODS

Computed tomography data from 103 normal subjects aged 8-12 months were compiled and a 3D computational model of the skull was generated for each subject. The models were mathematically registered to a baseline model for each month of age within this range and then averaged, resulting in a single 3D point cloud. An external cranial surface was subsequently passed through the point cloud and its shape and size customized to fit the head circumference of individual patients.

RESULTS

The resultant fabricated skull models provide a novel and applicable tool for a detailed, quantitative comparison between the normative and patient skulls for preoperative planning and practice for a variety of craniofacial procedures including vault remodeling. Additionally, it was possible to extract the suprafrontal orbit anatomy from the normative model and fabricate a bandeau template to guide intraoperative reshaping.

CONCLUSIONS

Normative head shapes for pediatric patients have wide application for craniofacial surgery including planning, practice, standarized operative repair, and standardized measurement and reporting of outcomes.

Discriminating preoperative features of pleuropulmonary blastomas (PPB) from congenital cystic adenomatoid malformations (CCAM): a retrospective, age-matched study

BACKGROUND

The etiopathogenesis of pleuropulmonary blastoma (PPB) and its relationship to congenital cystic adenomatoid malformation (CCAM) remain controversial. Our recent analysis indicates that both the co-incidental occurrence and the outcome of PPB among CCAM patients are significant. We report here on our efforts to determine clinical and radiological features discriminating PPB from CCAM preoperatively.

MATERIALS & METHODS

A retrospective analysis of all patients treated for PPB and CCAM between 1981 and 2008 at 2 tertiary academic centers under a centralized, single payer healthcare system was performed (REB#1000013239). Clinical, radiological and demographic data were analyzed. PPB patients were secondarily age matched with CCAM patients (± 10% age difference in months), and clinical, radiological and demographic variables were compared. Descriptive statistics and non-parametric analysis were used.

RESULTS

A total of 10 PPB patients was identified. Median age at diagnosis was 24 months; the male to female ratio was 5:5. No PPB patients had an antenatal diagnosis (p<0.01). 9 were symptomatic, with symptoms including dyspnea (7/10), upper respiratory infection (6/10), poor weight gain (3/10), and 1 patient was asymptomatic. 5 of 10 patients had solid parts on CT, of which 4 out of 5 were diagnosed preoperatively as PPB and 1 out of 5 as CCAM. 5 of 10 were predominantly cystic of which none was diagnosed preoperatively as PPB (p=0.0476). Given that most CCAM patients are now diagnosed antenatally, only 5 PPB patients could be age-matched with CCAM patients. In the predominantly cystic PPB patients (n=5), no significant discriminating clinical and radiological features were identifiable when compared preoperatively with age-matched CCAM patients.

CONCLUSION

PPB patients continue to represent a diagnostic challenge. Asymptomatic and predominantly cystic PPB remain indistinguishable from CCAM preoperatively. A high index of suspicion for PPB must be considered in any child presenting with cystic lung lesions beyond early infancy, particularly in a child with poor weight gain.

Regulation of Sox9 by Sonic Hedgehog (Shh) is essential for patterning and formation of tracheal cartilage

We report that Sonic Hedgehog (Shh) regulates both formation and patterning of tracheal cartilage by controlling the expression pattern and level of the chondrogenic gene, Sox9. In Shh(-/-) tracheo-esophageal tubes, Sox9 expression is transient and not restricted ventrally to the site of chondrogenesis, and is absent at the time of chondrogenesis, resulting in the failure of tracheal cartilage formation. Inhibition of Hedgehog signalling with cyclopamine in tracheal cultures prevents tracheal cartilage formation, while treatment of Shh(-/-) tracheal explant with exogenous Shh peptide rescues cartilage formation. Both exogenous Bmp4 and Noggin rescue cartilage phenotype in Shh(-/-) tracheal culture, while promoting excessive cartilage development in wild-type trachea through induction of Sox9 expression. The ventral and segmented expression of Sox9 in tracheal primordia under Shh modulated by Bmp4 and Noggin thus determine where and when tracheal cartilage develops. These results indicate that Shh signalling is a critical determinant in tracheal cartilage development.

A simple in vitro culture system for tracheal cartilage development

Semi-circular tracheal cartilage is a critical determinant of maintaining architectural integrity of the respiratory airway. The current effort to understand the morphogenesis of tracheal cartilage is challenged by the lack of appropriate model systems. Here we report an in vitro tracheal cartilage system using embryonic tracheal–lung explants to recapitulate in vivo tracheal cartilage developmental processes. With modifications of a current lung culture protocol, we report a consistent in vitro technique of culturing tracheal cartilage from primitive mouse embryonic foregut for the first time. This tracheal culture system not only induces the formation of tracheal cartilage from the mouse embryonic foregut but also allows for the proper patterning of the developed tracheal cartilage. Furthermore, we show that this culture technique can be applied to culturing other types of cartilage in vertebrae, limbs, and ribs. We believe that this novel application of our in vitro culture system will facilitate the manipulation of cartilage development under various conditions and thus enabling us to advance our current limited knowledge on cartilage biology and development.

A single center 26-year experience with treatment of esophageal achalasia: is there an optimal method?

PURPOSE

Treatment modalities for achalasia are evolving and remain controversial. Herein, we report the relative efficacy and outcomes after dilatation or myotomy in children with achalasia.

METHODS

A retrospective analysis of all children treated for achalasia at a tertiary center from 1981 to 2007 was performed (n = 40). Demographics, presenting symptoms, perioperative parameters, and outcomes were analyzed using t tests and chi(2) statistics.

RESULTS

Thirty patients were initially treated by esophageal dilatation (ED), whereas 10 were treated by laparoscopic or open Heller myotomy (HM). Both groups were similar with respect to age (10.6 vs 12.4 years; P = .19). There were 18 males and 12 females in the ED group, compared to 5 males and 5 females in the HM group (P = .72). Mean duration of symptoms before diagnosis, including dysphagia, vomiting, food sticking, chest pain, and weight loss, was 15.9 months for ED and 10.7 months for HM (P = .41). Mean time from diagnosis to initial intervention was 76 days in ED vs 86 days in HM (P = .78). Subsequent interventions by myotomy or both dilatation and myotomy were required in 9 (30%) of 30 patients in the ED group and 2 (20%) of 10 patients in the HM group (P = .70). A clear transition from open to laparoscopic approach occurred between 1995 and 2001. Mean operating times were comparable (186.3 vs 156.0 minutes; P = .48). Of 14 laparoscopic myotomies, 11 (79%) had fundoplication, and 2 (18%) of the 11 were converted to open procedure. Intraoperative mucosal perforation rates were similar between open and laparoscopic groups (17% vs 18%). At follow-up, 32% of ED patients vs 43% HM had complete symptom relief (mean follow-up duration, 75.2 months; SD, 196.5).

CONCLUSION

Both dilatation and myotomy are effective immediate treatment of achalasia. A clear transition to and preference for laparoscopic approach has occurred in the treatment of achalasia in children.

Congenital and acquired single-lung patients: long-term follow-up reveals high mortality risk

PURPOSE

Single-lung patients are uncommon. Case reports suggest that these patients have significant morbidity and mortality risks because of associated anomalies, airway obstruction as well as decreased pulmonary reserve. This study was designed to review morbidity and mortality of single-lung patients.

METHODS

A retrospective review of single-lung patients admitted to our hospital from January 1988 to June 2007.

RESULTS

Twelve single-lung patients were treated in our hospital with mean follow-up of 22.9 months. Six congenital lung aplasia patients presented as neonates, with 2 diagnosed antenatally. Of 4 patients with respiratory distress, 3 required surgical interventions to correct airway symptoms. Three patients died before 9 months of age because of respiratory failure, sepsis, or cardiac arrest. The remaining survivors have minimal respiratory distress. There were 6 pneumonectomy patients as follows: 5 for malignancies and 1 for bronchiectasis. There were 2 deaths from recurrent disease. Four patients had respiratory symptoms with one patient requiring tissue expander insertion for the correction of airway torsion from mediastinal shift.

CONCLUSIONS

The morbidity and mortality of infant single-lung patients are significant. Respiratory distress from decreased pulmonary reserve must be distinguished from airway obstruction because of mediastinal shift. Bronchoscopic assessment was invaluable to the diagnosis and management of these patients.

Physiologic predictors for the need for patch closure in neonatal congenital diaphragmatic hernia

Technically expedient repair of CDH defects is desirable. With increasing trend toward thoracoscopic repair, herein we examine physiologic predictors for the need for patch closure (PC) versus primary closure. All neonates who underwent surgical repair of CDH defects in a geographically defined region between 1992 and 2002 were included (n = 210). Two groups of patients were compared, primary repair (PR) versus PC. The 25th quartile was used as a cut off point for continuous variables. Univariate and multivariate logistic regression were performed. One hundred and fifty neonates underwent open PR (71.43%) versus 28.57% had PC. On univariate analyses the following variables were significantly associated with the need for PC: prenatal diagnosis, birth weight <2.7 kg, gestational age <37 weeks, APGAR at 5 min <6, immediate postnatal PCO(2) >34, Immediate oxygen saturation <93%, use of Nitric oxide and the need for high frequency oscillation (HFO). On multivariate analyses, only a PCO(2) >34 and the need for HFO were significantly associated with PC. Neonates with an initial PCO(2) >34 or need HFO pre-operatively should be excluded from attempts to repair the CDH thoracoscopically based on their higher potential need for PC with its entailed technical difficulty and increased operative time.

The use of the score for neonatal acute physiology-perinatal extension (SNAPPE II) in perforated necrotizing enterocolitis: could it guide therapy in newborns less than 1500 g?

BACKGROUND

Only a handful of clinical parameters other than body weight are used in managing LBW newborns with perforated necrotizing enterocolitis (NEC). Here, we determined clinical use of score for neonatal acute physiology-perinatal extension (SNAPPE II) score in the surgical decision, peritoneal drain (PD) vs PD + laparotomy in low birth weight (LBW) newborns with perforated NEC.

PATIENTS AND METHOD

A retrospective study of all neonates weighing less than 1500 g with the diagnosis of perforated NEC between 2000 and 2006 was performed. Patients were categorized in 2 groups--PD alone vs PD + laparotomy. The SNAPPE score was calculated at various days of clinical evolution. The primary outcome of mortality was used, and comparisons using univariate and multivariate analyses were performed.

RESULTS

Of 39 patients identified, 20 were treated with PD alone, whereas 19 had PD and laparotomy. The mean gestational age (25.6 vs 26.6 weeks) and the mean birth weight (795 vs 910 g) were comparable (P > .05). There were no differences between PD group and LAP group with regard to SNAPPE scores calculated on the day of admission (P = .057), the day before the drain insertion (P = .167) and the day after the drain insertion (P = .66). When considering survival as the dependent variable while controlling for the treatment assignment, the modified SNAPPE score after PD drain insertion in group PD was significantly higher than in the PD + laparotomy group (21.4 vs 9.47; P = .009).

CONCLUSION

The modified SNAPPE score is a good predictor of mortality after the PD insertion. A post-PD insertion, high SNAPPE value was correlated with increased mortality regardless of an additional laparotomy. External validation of the modified SNAPPE score in a large patient population is required before its use in guiding treatment decisions.

Eosinophilic esophagitis and intermediate esophagitis after tracheoesophageal fistula repair: a case series

BACKGROUND

Eosinophilic esophagitis (EE) is often missed or underdiagnosed in children, particularly in the setting of reflux disease associated with tracheoesophageal fistula (TEF). Intermediate esophagitis (IE) is a recently described condition, which includes characteristics of gastroesophageal reflux disease and EE but does not present with enough eosinophils on biopsy to diagnose EE. Here we present a case series of EE and IE associated with TEF, and their clinical manifestations.

METHODS

A retrospective analysis including clinical presentation, endoscopic and pathologic findings, and treatment of 4 patients with EE and 4 patients with IE who presented between 2003 and 2007 was performed.

RESULTS

Male dominance was found equally in both groups (75%), and most patients had a personal history of atopy (87.5%). Food allergies were seen mainly in the EE group (75%). The most frequent primary symptoms in both groups were dysphagia for solids (75%) and for liquids (25%). The median age at diagnosis was 9.8 vs 11.2 years in the EE and IE groups, respectively. On endoscopy, both groups had similar findings including furrows (EE, 75%; IE, 66.6%) and white plaques (EE, 50%; IE, 33.3%). In both groups, almost all patients had basal cell hyperplasia on biopsy (EE, 100%; IE, 75%). Degranulated surface eosinophils (50%) and eosinophilic abscess (25%) were found in the EE group only. Elongated rete papillae were more often seen in EE biopsies (50%) compared with IE biopsies (25%). Peripheral serum eosinophilia was seen in all EE patients and in 33% of the IE patients. The only effective treatment with complete resolution of the symptoms was the topical or systemic application of steroids.

CONCLUSIONS

The diagnosis of EE and IE is frequently missed or delayed. Eosinophilic esophagitis should be suspected in reflux disease refractory to conventional treatment, particularly in the setting of TEF. Intermediate esophagitis represents an entity that includes findings of gastroesophageal reflux disease and EE. Endoscopic biopsies are diagnostic for both conditions and allow institution of specific medical treatment.

Canadian Pediatric Surgical Network: a population-based pediatric surgery network and database for analyzing surgical birth defects. The first 100 cases of gastroschisis

PURPOSE

Outcomes studies for gastroschisis are constrained by small numbers, prolonged accrual, and nonstandardized data collection. The aim of this study is to create a national pediatric surgical network and database for gastroschisis (GS) that tracks cases from diagnosis to hospital discharge.

METHODS

The 16-center network serves a population of 32 million. Gastroschisis cases are ascertained at prenatal diagnosis. Perinatal data include maternal risk and fetal ultrasound variables, delivery plan and outcome, a postnatal bowel injury score, intended and actual surgical treatment, and neonatal outcomes. Institutional review board-approved data collection conforms to regional privacy legislation. Deidentified data are centralized and accessible for research through the network steering committee.

RESULTS

To date, 114 cases of pre- and/or postnatal gastroschisis have been uploaded. Of 106 live-born infants (40 [38%] by cesarean delivery), 100 had complete records, and overall survival to discharge was 96%, with a mean survivor length of stay (LOS) of 46 days. Infants treated with attempted urgent closure (61%) had significantly shorter LOS (42 vs 57 days; P = .048) but comparable LOS compared with those treated with silos and delayed closure. Fetal bowel dilation 18 mm or greater did not predict a difference in outcome.

CONCLUSION

Population-based databases allow rapid case accrual and enable studies that should aid in the identification of optimal perinatal treatment.

The current state of congenital tracheal stenosis

Congenital tracheal stenosis (CTS) is an uncommon condition that has challenged pediatric surgeons for decades. Patients with CTS can present with a wide spectrum of symptoms and varying degrees of severity. In addition, a variety of techniques have been devised to repair this malformation. A review of these procedures and our suggestions for clinical standards and practice guidelines will be presented in this paper. A retrospective review of the literature on CTS from 1964 to 31 March, 2006. There is not one standard technique for the repair of CTS, as individualized approach to each patient and airway lesion is necessary to optimize patient management; nevertheless there is a consensus about segmental resection and anastomosis being best for short segment stenosis while slide tracheoplasty is most effective for the long-segment ones. Conservative management is also an option for select group of patients with careful and close follow up. Survival following surgery over the years has improved, but mortality remained high, particularly in a specific subset of patients presenting at the age less than 1 month with associated cardiac malformations. In conclusion, CTS remains a significant challenge for pediatric surgeons. Additional research is required to improve our understanding of the pathogenesis of CTS, and to develop evidence-based treatment protocols for the entire spectrum of presentation including conservative management.

The Novel Hemoglobin-based Oxygen Carrier HRC 101 Improves Survival in Murine Sickle Cell Disease

Background

Erythrocyte transfusion decreases morbidity in sickle cell disease, but is not without risk. Use of a hemoglobin-based oxygen carrier could offer the benefits of erythrocyte transfusion while reducing related complications. The authors tested the hypothesis that the novel hemoglobin-based oxygen carrier, HRC 101, would improve survival during exposure to acute hypoxia in a murine model of sickle cell disease, the transgenic mouse expressing hemoglobin SAD (alpha2beta2).

Methods

Wild-type (n = 30) and transgenic SAD (n = 36) mice received 0.02 ml/g HRC 101 (hemoglobin concentration, 10 g/dl) or an equal volume of 5% albumin. Thirty percent or 6% oxygen was administered to spontaneously breathing mice during halothane anesthesia (inspired concentration, 0.5%). The time to cessation of cardiac electrical activity was recorded. Survival was compared using Kaplan-Meier analysis.

Results

Control mice survived the 60-min study period, whether breathing 30% or 6% oxygen. In contrast, all SAD mice given albumin and 6% oxygen died, with a median survival time of 9.0 min (interquartile range, 6.9-11.6 min; P &lt; 0.0001). HRC 101 significantly increased survival in SAD mice breathing 6% oxygen. Of 12 SAD mice given HRC 101 and 6% oxygen, 4 survived the entire study period and 8 died, with a median survival time of 48 min (19-60 min; P &lt; 0.0001 vs. albumin).

Conclusion

HRC 101 significantly decreased sickle-related mortality during exposure to acute hypoxic stress in transgenic mice expressing hemoglobin SAD. HRC 101 warrants further evaluation as a therapeutic modality in sickle cell disease.

Predicting the need for fundoplication at the time of congenital diaphragmatic hernia repair

PURPOSE

This study was conducted to examine the preoperative factors predictive of subsequent intervention for gastroesophageal reflux (GER) in children with congenital diaphragmatic hernia (CDH).

METHODS

We conducted a retrospective cohort study on children who underwent repair of a CDH between January 1, 1995, and December 31, 2002 with follow-up continuing to September 1, 2005. Excluded in the study were children who died during their first admission, or who underwent fundoplication at the time of CDH repair. Univariate and multivariate logistic regressions were performed to examine preoperative factors predictive of subsequent intervention (fundoplication or gastrojejunal tube placement).

RESULTS

Of 86 children, 13 underwent intervention (fundoplication, 10; gastrojejunal tube, 3) for GER. Univariate predictors included the following: right-sided CDH, use of nonconventional ventilation, liver within the chest, and patch closure of the CDH. However, only liver within the chest and patch closure of the CDH were significant predictors in a multiple variable analysis. The positive and negative predictive values of the multivariate model were 69.2% and 87.7%, respectively.

CONCLUSIONS

Infants with CDH who have liver within the chest or require patch closure of their hernia are at increased risk for subsequent intervention for GER. These children may represent a subpopulation that would benefit from fundoplication at the time of CDH repair.

Thoracoscopic versus open resection of congenital lung lesions: a case-matched study

PURPOSE

The purpose of the study was to compare the outcomes in children undergoing thoracoscopic versus open resection of congenital lung lesions.

METHODS

Retrospective review of 12 consecutive children (<3 years of age) undergoing thoracoscopic resection of a congenital lung lesion between 2004 and 2005 was performed. Intraoperative and early postoperative results were compared with randomly selected age- and sex-matched (2:1) patients undergoing thoracotomy between 2000 and 2005.

RESULTS

Twelve children underwent thoracoscopic resection and were compared with 24 that underwent thoracotomy. Seventy five percent of the lesions in both groups were congenital cystic adenomatoid malformations. There were no major intraoperative complications. Two thoracoscopic procedures were converted to a thoracotomy. Perioperative outcomes including operative time, length of stay, duration and volume of chest tube drainage, and dose and duration of intravenous opioids were similar for the procedures. However, children undergoing thoracoscopic procedures were less likely (odds ratio = 0.07) to have received adjunctive regional anesthesia. Overall morbidity was 33% thoracoscopic and 25% open (P = .70).

CONCLUSION

Thoracoscopic resection is a safe and feasible alternative to open resection of congenital lung lesions. Examination of long-term advantages of the thoracoscopic approach such as decreased risk of chest wall deformity and scoliosis and improved cosmesis will require longer follow-up.

A role for laparoscopic approach in the treatment of biliary atresia and choledochal cysts

BACKGROUND/PURPOSE

Indications for a laparoscopic approach in the management of biliary atresia and choledochal cysts in children are not clearly defined. We present our initial experience with 9 consecutive laparoscopic cases, and compare them to the traditional open approach.

METHODS

A retrospective comparison of all consecutive operations for biliary atresia and choledochal cysts from January 2000 to May 2006 was undertaken. We evaluated the patient's age at operation, operative time, return of bowel function postoperatively, length of hospital stay, complications, and the need for subsequent liver transplantation. Mann-Whitney U test was used for statistical analysis.

RESULTS

A total of 45 portoenterostomies and choledochojejunostomies were performed, including 9 laparoscopic and 36 open procedures. Patients with choledochal cysts were older than patients with biliary atresia. All the compared parameters were similar and there was no difference in outcomes between the laparoscopic and the open groups.

CONCLUSIONS

Our initial experience is encouraging and indicates that the laparoscopic approach is technically feasible, safe, and effective, with a low morbidity and a comparable outcome to the open technique. Longer follow-up of a larger patient cohort is needed.

Women’s Satisfaction With the Current State of Prenatal Care for Pregnancies Complicated by Fetal Anomalies: A Survey of Five Academic Perinatal Units in Ontario

OBJECTIVE

To assess women's satisfaction with the current state of prenatal care for pregnancies complicated by congenital anomalies.

METHODS

We conducted a cross-sectional survey of 251 women with pregnancies complicated by congenital anomalies. The women were recruited from five Ontario hospitals (Mount Sinai Hospital in Toronto, Hamilton Health Sciences Centre, St. Joseph's Health Care in London, Kingston General Hospital, and The Ottawa Hospital) at the time of referral. A seven-question, self-administered questionnaire developed by an expert panel was used to collect data from the study subjects about satisfaction with prenatal care at antenatal clinics. The women's level of satisfaction was measured using a 5-point scale (1 = least satisfactory and 5 = most satisfactory). Demographic information and information about women's medical and obstetrical history, and obstetrical knowledge was also collected. Descriptive analyses were performed, and relative risks (RR) were calculated to estimate measures of association.

RESULTS

Most of the study subjects (> 90%) had a high level of education and were married or in a common-law relationship, and about 80% came from high-income families. The mean age of the study subjects was 31.4 years. The mean gestational age at the first visit with a doctor or midwife was 8.5 weeks, at first being told of a concern with their pregnancy was 18.6 weeks, and at the first visit with an obstetric specialist in the community was 19.6 weeks. Mean scores for each item of satisfaction measure varied from 4.05 to 4.53, and the mean score for women's overall satisfaction was 29.7 (95% confidence intervals [CI] 28.9-30.4). There was a statistically significant association between women's opinion and knowledge of prenatal testing and their level of satisfaction with prenatal care. Women who had difficulty understanding what a doctor or midwife was telling them were less satisfied with prenatal care than women without such difficulty (RR 3.21; 95% CI 2.14-4.81). Language and ethnic diversity were not associated with the level of satisfaction.

CONCLUSION

In Ontario, of women whose pregnancies are complicated by congenital anomalies, those who are less knowledgeable about their pregnancies are more likely to be dissatisfied with their prenatal care. Overall, however, most women are satisfied with their prenatal care.

The fetal alert network: an innovative program of access to care, surveillance, and education for birth defects in Ontario

Optimal pregnancy outcomes rely on coordinated timely access to appropriate evidence-based clinical care. This is particularly true for pregnant women carrying fetuses diagnosed with birth defects. A systematic approach to prenatal care is ideal, but Ontario has traditionally lagged behind other regions in this regard. In 2004, in response to this challenge, the Fetal Alert Network (FAN) was established with funding support from the Ontario Ministry of Health and Long-Term Care. FAN is composed of five multidisciplinary regional health care teams of nurse coordinators working in close collaboration with primary obstetrical care providers, medical geneticists, specialists in maternal fetal medicine, and pediatric specialists. The teams facilitate access to subspecialists through patient triage and referral, provide outreach education, and act as local experts and change agents to improve care. A key objective is to go beyond a traditional surveillance system to the linkage of service provision with outcomes and effectiveness. FAN's objectives are to ensure optimal health care access and delivery at all levels, to promote coordination and collaboration among providers, to provide timely and accurate information about health system utilization and clinical outcomes, and to educate patients and primary care providers about prenatal diagnosis. Program evaluation is currently underway. Preliminary analyses indicate that achievement of these objectives has resulted in seamless coordinated access to service for the targeted group of patients, as well as enhanced communication among providers; accessible education and information; and precise, accurate, and timely health care data and information.

The role of Shh transcription activator Gli2 in chick cloacal development

Patterning and differentiation along the dorsal-ventral (D-V) axis lead to cloacal partitioning into ventral urinary and dorsal alimentary tracts in most mammals, but not birds and fish. We previously reported that the major activator of Sonic hedgehog (Shh) signaling transcription factor Gli2 plays an essential role in cloacal partitioning along the D-V axis in a mouse model. Here, we report that chick cloacal patterning and differentiation is along the anterior-posterior axis. During chick cloacal formation, Shh is expressed strongly in hindgut endoderm; Gli2 is very weakly detected in the surrounding hindgut mesoderm. In the mesoderm of the cloacal region, the over-expression of the constitutively active form of mouse Gli2 has been shown to: not induce cloacal partitioning along the D-V axis; induce expression of Ptch1, Gli2, bmp4, wnt5a, and hoxd-13, which have been previously shown to play a role in hindgut patterning; increase cell proliferation; and reduce apoptosis. Interestingly, p63 expression in the cloacal endoderm is also up-regulated, suggesting an interaction between the Shh and p63 pathways. In conclusion, Gli2 alone is insufficient to induce partitioning along the D-V axis in the chick embryo. However, Gli2 regulates both epithelial and mesenchymal cell proliferation and apoptosis during cloacal development.

DeltaNp63 plays an anti-apoptotic role in ventral bladder development

The bladder, the largest smooth-muscle organ in the human body, is responsible for urine storage and micturition. P63, a homolog of the p53 tumor-suppressor gene, is essential for the development of all stratified epithelia, including the bladder urothelium. The N-terminal truncated isoform of p63, DeltaNp63, is known to have anti-apoptotic characteristics. We have established that DeltaNp63 is not only the predominant isoform expressed throughout the bladder, but is also preferentially expressed in the ventral bladder urothelium during early development. We observed a host of ventral defects in p63-/- embryos, including the absence of the abdominal and ventral bladder walls. This number of ventral defects is identical to bladder exstrophy, a congenital anomaly exhibited in human neonates. In the absence of p63, the ventral urothelium was neither committed nor differentiated, whereas the dorsal urothelium was both committed and differentiated. Furthermore, in p63-/- bladders, apoptosis in the ventral urothelium was significantly increased. This was accompanied by the upregulation of mitochondrial apoptotic mediators Bax and Apaf1, and concurrent upregulation of p53. Overexpression of DeltaNp63gamma and DeltaNp63beta in p63-/- bladder primary cell cultures resulted in a rescue, evidenced by significantly reduced expressions of Bax and Apaf1. We conclude that DeltaNp63 plays a crucial anti-apoptotic role in normal bladder development.

The role of conservative management in congenital tracheal stenosis: an evidence-based long-term follow-up study

BACKGROUND/PURPOSE

Surgery has been the management of choice for severe congenital tracheal stenosis (CTS). The role of conservative management of CTS however is not clear. The aim of this study is to characterize the natural history of CTS, review the radiologic evidence of tracheal growth, and evaluate the clinical outcome and selection criteria of conservative management of CTS.

METHODS

A retrospective study was carried out on 22 consecutive children with symptomatic CTS admitted into a single institution between 1982 and 2001. The patients were categorized into operation (n = 11) and observation (n = 11) groups. Six patients of the observation group were followed up with serial computed tomography scan. Their tracheal growth was compared with that of healthy children of the same age.

RESULTS

The mortality rates of observation and operation groups were 9% and 27%, respectively, although the latter group consisted of more severely affected patients. The pathologic categorization of the CTS influenced the survival rates (P = .046, chi2), with the long segment type having the worst prognosis (67%). Serial computed tomography scans of 6 conservatively managed patients revealed that all stenotic tracheas continued to grow (P = .039, 2-tailed paired Student's t test). Of the 6 stenotic tracheas, 5 grew at a faster-than-normal rate, and the stenotic tracheal diameters approached those of normal diameters by the age of 9 years.

CONCLUSIONS

The management of patients with symptomatic CTS should be individualized. A selected group of patients with CTS can be safely managed nonoperatively.

A novel treatment of congenital duodenal stenosis: image-guided treatment of congenital and acquired bowel strictures in children

BACKGROUND

Image-guided balloon dilatation has been used in adults as an alternative to standard surgical treatment of intestinal stricture. The experience in children is limited. We report our results with this procedure in the management of both congenital and acquired intestinal stenosis in children.

MATERIALS AND METHODS

A retrospective analysis was done of children younger than 2 years of age who underwent balloon dilatation of small and large intestinal stenosis between 1994 and 2003.

RESULTS

Eleven children underwent dilatation during the study period. Two of these children had congenital duodenal stenosis, and this represents the first report of nonoperative management of this condition. Three children underwent dilatation of small bowel strictures and 6 had dilatation of colonic and rectal strictures. Necrotizing enterocolitis was the most common (6/9) etiology of stricture. Ten of 11 patients did not require subsequent operative management although 3 children required further dilatations. The mean follow-up was 36.5 months (range, 13 days-103 months). One patient underwent a subsequent dilatation that was unsuccessful, and required operative resection of a 5-cm stricture. There was one complication, a small leak that was managed nonoperatively.

CONCLUSION

Image-guided balloon dilatation holds promise as an alternative to surgical treatment in children with congenital or acquired stenosis of the small or large bowel, and should be considered in select patients with short strictures.

Surgical challenges associated with intensive treatment protocols for high-risk neuroblastoma

BACKGROUND

High-risk neuroblastoma (NB; age, >1 year; INSS stage 4) is associated with a poor outcome. At our institution, the current dose-intensive high-risk Children's Oncology Group protocol for advanced NB appears to have a higher surgical complication rate as compared with previous protocols.

METHODS

All stage 4 patients (n = 51) entered in high-risk protocols between 1995 and 2005 were analyzed. Patients in the current high-risk protocol, Children's Oncology Group A3973 (n = 22), were compared with those in the 2 previous protocols, CCG 3891 and POG 9341 (n = 29).

RESULTS

Patients were comparable in their mean age and tumor markers, including Shimada histology, MYCN amplification, 1p deletion, tumor origin, and extent of metastasis. However, transfusion requirement (86% vs 45%; P = .0019), postoperative infection rate (32% vs 3%; P = .02), and other postoperative issues including nutritional support (45% vs 3%; P = .0001) were significantly higher with the current protocol. No perioperative mortality was noted in either group, and the extent of resectability and margins were similar. Importantly, with the current protocol, the survival rate was higher (P = .0022) and the recurrence rate was significantly lower (P = .0003).

CONCLUSIONS

Despite higher surgical morbidity associated with the current high-risk protocol (2.59 vs 0.86 complications/person; P < .01), the recurrence rate is lower and interim survival rate is improved for patients with high-risk NB. Therefore, the higher surgical complication rates associated with the current high-risk protocol are acceptable.

Long-term outcomes of clinically significant vascular rings associated with congenital tracheal stenosis

AIM

Congenital tracheal stenosis (CTS) associated with vascular rings (VRs) is considered a secondary condition, but relative indications for selective VRs or combined VR and CTS repairs are unclear. Here, we report long-term outcomes after VR repair associated with tracheal narrowing (TN).

METHOD

Retrospective analysis of patients admitted to a single institution with VR from 1982 to 2004. Of 131 patients with VR (Cardiac Registry Database), 29 (19 males, 10 females; age range, 0 days-4 years) associated with symptomatic TN. Patients were followed until age 18 years.

RESULTS

One hundred thirty-one patients with VR were categorized into 3 treatment groups. There were 102 patients with VR with no symptomatic TN treated by VR repair (4 deaths, 4% mortality). Of the 29 patients with VR + TN symptoms, 16 were treated by selective VR repair (mean age, 5.3 months; range, 17-288 days) with 3 deaths (19% mortality) and 13 underwent combined VR and CTS repairs (mean age, 11 months; range, 1 day-4 years) with 6 deaths (46% mortality), for an overall mortality of 31% (P < .01, chi2 test). Of the 102 patients with VR, 17 had intracardiac anomalies with 3 deaths (18% mortality). In contrast, 7 of 29 patients with VR with TN and intracardiac anomalies died (57% mortality); 3 patients in combined cardiac and CTS repairs (2 deaths, 67% mortality) and 4 in selective VR repairs (2 deaths, 50% mortality).

CONCLUSIONS

Not all cases of TN associated with VR require combined repairs. The presence of TN and/or intracardiac anomalies in patients with VR, however, increases mortality risk to the repair of VR. Surgical decision requires individualized clinical pathway.