Complex Cranial Vault Reconstruction Research Articles

Measuring coagulopathy in pediatric craniofacial surgery.

The goal of this study was to describe hematologic and coagulation laboratory parameters and identify if these laboratory studies could predict blood loss in a cohort of pediatric patients undergoing complex cranial vault reconstruction (CCVR) for repair of craniosynostosis. We reviewed records from 95 pediatric CCVR patients between 2015 and 2019. Primary outcome measures were hematologic and coagulation laboratory parameters. Secondary outcome measures were intraoperative and postoperative calculated blood loss (CBL). Preoperative laboratory values were within normal limits and did not predict outcomes. Intraoperative platelet count and fibrinogen predicted CBL but without clinically relevant thrombocytopenia or hypofibrinogenemia. Intraoperative prothrombin time (PT) and partial thromboplastin time (PTT) predicted perioperative CBL, possibly reflecting surgically induced coagulopathy. Postoperative laboratory values did not predict postoperative blood loss. We found that standard hematologic and coagulation laboratory parameters predicted intraoperative and postoperative blood loss but provided limited mechanistic information to improve our understanding of coagulopathy in craniofacial surgery.

Antifibrinolytics Are Not Associated With Reduced Blood Loss in Minimally-Invasive Endoscopic-Assisted Craniectomy for Repair of Single-Suture Craniosynostosis

Minimally-invasive endoscopic-assisted craniectomy (EAC) achieves similar functional and cosmetic outcomes, whereas reducing morbidity risk that is often associated with complex cranial vault reconstruction. Antifibrinolytics (AF) usage to limit blood loss and transfusion requirements during complex cranial vault reconstruction has been studied extensively; however, studies are limited for AF therapy in EAC. The aim of this single-center retrospective observational cohort pilot study was to evaluate whether the use of AF was associated with reduced blood loss in infants undergoing EAC. The authors hypothesized that there would be no difference in blood loss between patients who received AF and those that did not receive AF during EAC. Non-syndromic patients who underwent single-suture EAC were retrospectively evaluated. Primary outcome measure was intraoperative calculated blood loss (mL/kg). Secondary outcome measures included perioperative red blood cells transfusion volumes, number of blood donor exposures, and pediatric intensive care unit and total hospital length of stay. Study cohort demographic and outcome data were analyzed; Fisher exact test was used for categorical data, Student t test was used for continuous data. A P value of <0.05 was considered statistically significant. Forty-nine EAC patients were included in the study with 34 patients in the AF cohort and 15 patients in the non-AF cohort. There were no significant differences in demographics between the 2 groups. Additionally, there was no significant difference in intraoperative calculated blood loss or any secondary outcome measure. In our single-suture EAC study cohorts, AF administration was not associated with a decrease in blood loss when compared to those that did not receive AF therapy.

ε-Aminocaproic acid versus tranexamic acid in children undergoing complex cranial vault reconstruction for repair of craniosynostosis.

Complex cranial vault reconstruction (CCVR) for pediatric craniosynostosis is a high blood loss surgery, for which antifibrinolytic agents have been shown to reduce bleeding and transfusion requirements. The relative efficacy of ε-aminocaproic acid (EACA) versus tranexamic acid (TXA) has not yet been evaluated in this population. The aim of this retrospective study was to compare perioperative blood loss and transfusion in CCVR patients receiving EACA versus TXA. In a CCVR cohort of 95 children, 47 received EACA and 48 received TXA. We found no differences in demographics, adverse outcomes, calculated blood loss (CBL), or transfusion requirements between the two antifibrinolytic groups.

Blood Loss and Transfusion in Pediatric Craniofacial Surgery in the Antifibrinolytic Era

Background : Children undergoing complex cranial vault reconstruction (CCVR) for craniosynostosis experience high rates of bleeding and blood product transfusion, increasing the risk of perioperative complications. The most severe issues relate to the rate and extent of blood loss, which can be up to several times the patient's total blood volume and is often equated to controlled massive hemorrhage. ε-Aminocaproic acid (EACA) and tranexamic acid (TXA) are antifibrinolytic agents that have been shown to reduce intraoperative hemorrhage and transfusion requirements during CCVR. However, the relative efficacy of EACA vs. TXA in CCVR has not yet been evaluated. The aim of this study was to compare perioperative blood loss and need for transfusion in children receiving EACA and TXA. We hypothesized that TXA is associated with a greater decrease in blood loss and transfusion requirements when compared to EACA. Methods: All patients who underwent CCVR from September 2015 to December 2019 at our institution were retrospectively evaluated. The primary outcome measures included intraoperative estimated blood loss (EBL), red blood cell (RBC) transfusion volume (mL/kg), and calculated blood loss (CBL) (Kearney et al., Can J Anaesth 1989). Secondary outcome measures included hematologic and coagulation parameters. Study cohort demographic and outcome data were analyzed; Fisher's exact test was used for categorical data, student's t-test was used for continuous data. A p-value of &amp;lt; 0.05 was considered statistically significant. Results: 104 patients were included in the study with 48 patients in the EACA cohort and 56 patients in the TXA cohort. There were slightly more patients with syndromic craniosynostosis in the EACA group, but overall no significant differences in cohort characteristics (Table 1). Mean EBL (mL/kg) was slightly higher in the EACA group vs. the TXA group (21 ± 13 vs. 17 ± 10), but not statistically significant. Intraoperative mean CBL (34 ± 21mL/kg) and intraoperative percent blood volume lost (43 ± 26%) for the cohort were high, but these were equal between groups. Likewise, postoperative DO, CBL and percent blood volume lost were similar between groups. Overall, intraoperative RBC transfusion was required in 66 (64%) of patients and was similar between groups (69% of EACA patients vs. 59% of TXA patients). Intraoperative transfusion of other products was equal between groups. Postoperatively, 23 (22%) of patients required RBC transfusion. Postoperative blood product transfusions were equal between groups (Table 2). We compared routine hematologic and coagulation parameters peri-operatively and did not find any differences between the EACA and TXA group (Table 3). In the EACA group, there were 6 reported perioperative complications, including 2 suspected seizure events, as compared to 7 complications in the TXA group, which included 2 thromboembolic events. Discussion: Pediatric CCVR is a high blood loss surgery and this can lead to a consumptive coagulopathy for which intraoperative antifibrinolytic agents have been demonstrated to improve outcomes. We found no significant difference in blood loss, transfusion requirements, or hematologic parameters between patients who received EACA and TXA in our retrospective pediatric CCVR cohort. Overall there were 4 postoperative outcomes that could have been related to antifibrinolytic use (seizure, thromboembolism), but this was equal between groups and causality was not confirmed. Further research is needed to define optimal antifibrinolytic dosing and duration of therapy. While standard hematologic and coagulation parameters were similar between groups, the mechanisms of surgically induced coagulopathy in CCVR still need to be explored. Future studies investigating coagulation-based and inflammatory assays may be useful in defining surgical-induced coagulopathy. Disclosures No relevant conflicts of interest to declare.

Non-Invasive Venous waveform Analysis (NIVA) for volume assessment during complex cranial vault reconstruction: A proof-of-concept study in children.

BackgroundNon-Invasive Venous waveform Analysis (NIVA) is novel technology that captures and analyzes changes in venous waveforms from a piezoelectric sensor on the wrist for hemodynamic volume assessment. Complex cranial vault reconstruction is performed in children with craniosynostosis and is associated with extensive blood loss, potential life-threatening risks, and significant morbidity. In this preliminary study, we hypothesized that NIVA will provide a reliable, non-invasive, quantitative assessment of intravascular volume changes in children undergoing complex cranial vault reconstruction.ObjectiveTo present proof-of-concept results of a novel technology in the pediatric population.MethodsThe NIVA prototype was placed on each subject’s wrist, and venous waveforms were collected intraoperatively. Estimated blood loss and fluid/blood product administration were recorded in real time. Venous waveforms were analyzed into a NIVA value and then correlated, along with mean arterial pressure (MAP), to volume changes. Concordance was quantified to determine if the direction of change in volume was similar to the direction of change in MAP or change in NIVA.ResultsOf 18 patients enrolled, 14 had usable venous waveforms, and there was a significant correlation between change in NIVA value and change in volume. Change in MAP did not correlate with change in volume. The concordance between change in MAP and change in volume was less than the concordance between change in NIVA and change in volume.ConclusionNIVA values correlate more closely to intravascular volume changes in pediatric craniofacial patients than MAP. This initial study suggests that NIVA is a potential safe, reliable, non-invasive quantitative method of measuring intravascular volume changes for children undergoing surgery.

S16-09 SESSION 16: PLANNING/IMAGING – PART II SEPARATING CRANIOPAGUS TWINS: A 4 STAGE APPROACH USING 3D IMAGING TECHNOLOGY

Introduction: Craniopagus twins are the most rare form of conjoined twins, and successful separation poses a significant challenge to both neurosurgical and plastic surgical teams. Total craniopagus twins share a unified calvarium that houses two fused brains with shared venous sinuses. Orientation of total craniopagus twins, as classified by Stone and Goodrich, may be angular or vertical. To overcome the neurosurgical challenge is to separate two fused brains rotated at different orientations and safely separating the share venous system. The plastic surgery team aims to plan the complex cranial vault reconstruction of two fused calvaria. 3D technology was used to assist in these endeavors. One of the senior authors has previously separated 11 cases of craniopagus twins, and the advantages of our most recent approach using 3D technology will be discussed relative to these cases. Methods: Two sets of total craniopagus twins were separated in 4 stages (n=4). 3D technology was used for pre-operative planning, intra-operative execution, and post-operative analysis of reconstructive outcomes. Virtual surgical planning with 3D printed jigs and guides, 3D surface analysis, and 3D printed models were used at each stage. A two-team approach with neurosurgery and plastic surgery was employed at each stage, and 3D-technology was used by each team. Results: Two sets of total craniopagus twins were successfully separated using a 4-stage, two-team approach supplemented by 3D-technology. The neurosurgical team used 3D-printed models of the brains and vasculature to plan and perform dissection. Plastic surgery used VSP to select tissue expanders and design templates for incisions and osteotomies. 3D printed models offered intraoperative reference to safely separate the brain and its vasculature. 3D printed jigs and guides were fit on the calvarium to guide osteotomies for cranial vault reconstruction, and onto the scalp to guide soft tissue reconstruction. Conclusion: Separation the brain and its vasculature was aided by pre-operative 3D printed anatomic models that were then used as freely rotational reference intra-operatively. Calvarial and scalp reconstruction was improved with virtual surgical planning and 3D printed guides at each stage to precisely plan type and placement of tissue expanders, osteotomies and scalp rotation flaps. 3D technology offers anatomic reference and surgical guidance in the multistage separation of total craniopagus twins, and its potential to further assist in such complex surgical endeavors is a topic of continued investigation.

Predictors of transfusion outcomes in pediatric complex cranial vault reconstruction: a multicentre observational study from the Pediatric Craniofacial Collaborative Group.

Pediatric patients undergoing complex cranial vault reconstruction (CCVR) are at risk of significant perioperative blood loss requiring blood product transfusion. Minimizing allogeneic blood product transfusion is an important goal because of the associated risks and cost. The impact of patient and surgical variables on transfusion is unknown in this population. Our primary aim was to examine relationships between demographic and perioperative variables and blood product transfusion outcomes in CCVR. The multicentre Pediatric Surgery Perioperative Registry was checked for children undergoing CCVR between June 2012 and September 2016. Univariable and multivariable analyses were performed examining patient, procedure, and blood conservation variables and their relationship to three outcomes: intraoperative red blood cell-containing product (RBC-CP) transfusion, total perioperative blood donor exposures, and transfusion-free hospitalization. The registry search returned data from 1,814 cases. Age and surgical duration were the only variables significantly associated with all three outcomes studied. Predictors of reduced RBC-CP transfusion included lower American Society of Anesthesiologists (ASA) physical status and antifibrinolytic administration. Total cranial vault reconstruction, intraoperative vasoactive infusion, and presence of a tracheostomy predicted increased donor exposures. Increased body weight, higher preoperative hematocrit, and utilization of intraoperative cell saver and transfusion protocols were associated with transfusion-free hospitalization. Clinical factors associated with increased allogeneic blood product transfusion in pediatric CCVR include: age ≤ 24 months, ASA status ≥ III, preoperative anemia, prolonged surgical duration, lack of intraoperative antifibrinolytic use, lack of intraoperative cell saver use, and the lack of transfusion protocols.

Intraoperative Management by a Craniofacial Team Anesthesiologist is Associated With Improved Outcomes for Children Undergoing Major Craniofacial Reconstructive Surgery.

The benefits of using a dedicated team for complex surgeries are well established for certain specialties, but largely unknown for others. The aim of this study was to determine whether management by a dedicated craniofacial team anesthesiologist would impact perioperative outcomes for children undergoing major surgery for craniosynostosis. Sixty-two children undergoing complex cranial vault reconstruction were identified. Fifty-four patients were managed by the craniofacial anesthesia team, while 8 patients were not. Primary outcome measures were calculated blood loss, red blood cell transfusion volume, blood donor exposures, extubation rate, and postoperative complication rate. Secondary outcome measures included intraoperative opioid administration, crystalloid and colloid administration, intraoperative complication rate, and intensive care unit (ICU) and hospital length of stay. Children cared for by the craniofacial team had significantly lower calculated blood loss, reduced red blood cell transfusion volume, fewer blood donor exposures, less crystalloid administration, higher rate of postoperative extubation, fewer postoperative complications, and decreased ICU and hospital length of stay than patients who were managed by noncraniofacial team anesthesiologists. There were no significant differences in demographics, opioid administration, colloid volume administration, or intraoperative complication rates between the 2 groups. Management by a craniofacial team anesthesiologist was associated with improved outcomes in children undergoing major craniofacial reconstructive surgery. While some variability can be attributed to provider-volume relationship, these findings suggest that children may benefit from a subspecialty anesthesia team-based approach for the management of craniofacial surgery, and potentially other similar high-risk cases.

Predictors of perioperative complications in paediatric cranial vault reconstruction surgery: a multicentre observational study from the Pediatric Craniofacial Collaborative Group

BackgroundThe current incidence of major complications in paediatric craniofacial surgery in North America has not been accurately defined. In this report, the Pediatric Craniofacial Collaborative Group evaluates the incidence and determines the independent predictors of major perioperative complications using a multicentre database. MethodsThe Pediatric Craniofacial Surgery Perioperative Registry was queried for subjects undergoing complex cranial vault reconstruction surgery over a 5-year period. Major perioperative complications were identified through a structured a priori consensus process. Logistic regression was applied to identify predictors of a major perioperative complication with bootstrapping to evaluate discrimination accuracy and provide internal validity of the multivariable model. ResultsA total of 1814 patients from 33 institutions in the US and Canada were analysed; 15% were reported to have a major perioperative complication. Multivariable predictors included ASA physical status 3 or 4 (P=0.005), craniofacial syndrome (P=0.008), antifibrinolytic administered (P=0.003), blood product transfusion >50 ml kg–1 (P<0.001), and surgery duration over 5 h (P<0.001). Bootstrapping indicated that the predictive algorithm had good internal validity and excellent discrimination and model performance. A perioperative complication was estimated to increase the hospital length of stay by an average of 3 days (P<0.001). ConclusionsThe predictive algorithm can be used as a prognostic tool to risk stratify patients and thereby potentially reduce morbidity and mortality. Craniofacial teams can utilise these predictors of complications to identify high-risk patients. Based on this information, further prospective quality improvement initiatives may decrease complications, and reduce morbidity and mortality.

Improving Outcomes in a Complex Health Care System: Lessons From Complex Cranial Vault Reconstruction.

Reducing blood donor exposure (BDE) is a meaningful improvement goal for many conditions and procedures that require a transfusion of blood products. Complex cranial vault reconstruction (CCVR) in children is a procedure that routinely requires a large-volume blood transfusion, with intraoperative blood loss routinely exceeding the circulating blood volume1–4 and ongoing losses often leading to postoperative transfusions. Large-volume transfusions increase the risk for coagulopathy5 and a need for additional blood products; increasing donor exposure increases the risk for infection, transfusion reactions, and alloimmunization.6 Optimizing the transfusion management for CCVR requires a high degree of care coordination because multiple providers are involved in the care of these children in the preoperative, intraoperative, and postoperative setting.1 In addition, an optimal transfusion strategy for this particular population has not been previously established. In this issue of Hospital Pediatrics , Muhly et al7 report the use of sequential interventions and the evaluation of outcomes over time to achieve an overall goal of reducing BDEs. They also achieve a secondary goal of reducing the overall blood transfusion volume in the CCVR population. Although …

Care Standardization Reduces Blood Donor Exposures and Transfusion in Complex Cranial Vault Reconstruction.

Complex cranial vault reconstruction (CCVR) often requires a large-volume transfusion of blood products. We implemented a series of improvement interventions to reduce blood donor exposures (BDE) and transfusion requirements in CCVR. We implemented interventions over 4 epochs: (E1) reconstituted blood (1:1 ratio of donor-matched red blood cells and fresh-frozen plasma) for intraoperative transfusions, (E2) reconstituted blood plus postoperative transfusion guidelines, (E3) reconstituted blood plus intraoperative antifibrinolytics and postoperative guidelines, and (E4) fresh whole blood for intraoperative transfusion, antifibrinolytics, and postoperative guidelines. Primary outcomes, BDE, and total volume of blood products transfused are presented by using statistical process control charts, with statistical comparisons between each epoch and baseline data. We included 347 patients <72 months old who underwent CCVR between 2008 and 2016 (E1: n = 50; E2: n = 41; E3: n = 87; and E4: n = 169). They were compared with a baseline sample group of 138 patients who were managed between 2001 and 2006. Compared with our baseline group, patients in each epoch had a significant reduction in BDE (P = .02-<.0001). Conversely, compared with the baseline group, we observed an increase the volume of blood products transfused in E1 (P = .004), no difference in E2 (P = .6) or E3 (P = .46), and a reduction in the volume of blood products transfused in E4 (P < .0001). The implementation of sequential clinical improvement strategies resulted in a sustained reduction in BDE whereas only the use of whole blood resulted in a significant reduction in the total volume of blood products transfused in children undergoing CCVR.

Perioperative Outcomes and Management in Pediatric Complex Cranial Vault Reconstruction: A Multicenter Study from the Pediatric Craniofacial Collaborative Group.

The Pediatric Craniofacial Collaborative Group established the Pediatric Craniofacial Surgery Perioperative Registry to elucidate practices and outcomes in children with craniosynostosis undergoing complex cranial vault reconstruction and inform quality improvement efforts. The aim of this study is to determine perioperative management, outcomes, and complications in children undergoing complex cranial vault reconstruction across North America and to delineate salient features of current practices. Thirty-one institutions contributed data from June 2012 to September 2015. Data extracted included demographics, perioperative management, length of stay, laboratory results, and blood management techniques employed. Complications and outlier events were described. Outcomes analyzed included total blood donor exposures, intraoperative and perioperative transfusion volumes, and length of stay outcomes. One thousand two hundred twenty-three cases were analyzed: 935 children aged less than or equal to 24 months and 288 children aged more than 24 months. Ninety-five percent of children aged less than or equal to 24 months and 79% of children aged more than 24 months received at least one transfusion. There were no deaths. Notable complications included cardiac arrest, postoperative seizures, unplanned postoperative mechanical ventilation, large-volume transfusion, and unplanned second surgeries. Utilization of blood conservation techniques was highly variable. The authors present a comprehensive description of perioperative management, outcomes, and complications from a large group of North American children undergoing complex cranial vault reconstruction. Transfusion remains the rule for the vast majority of patients. The occurrence of numerous significant complications together with large variability in perioperative management and outcomes suggest targets for improvement.

Craniosynostosis and Resynostosis

Craniosynostosis occurs in approximately 1 in 2,000 children and results from the premature fusion of ≥1 cranial sutures. If left untreated, craniosynostosis can cause numerous complications as related to an increase in intracranial pressure or as a direct result from cranial deformities, or both. More than 100 known mutations may cause syndromic craniosynostosis, but the majority of cases are nonsyndromic, occurring as isolated defects. Most cases of craniosynostosis require complex cranial vault reconstruction that is associated with a high risk of morbidity. While the first operation typically has few complications, bone rapidly regrows in up to 40% of children who undergo it. This resynostosis typically requires additional surgical intervention, which can be associated with a high incidence of life-threatening complications. This article reviews work related to the dental and maxillofacial implications of craniosynostosis and discusses clinically relevant animal models related to craniosynostosis and resynostosis. In addition, information is provided on the imaging modalities used to study cranial defects in animals and humans.

Effect of isolation of periosteum and dura on the healing of rabbit calvarial inlay bone grafts.

Little is understood about the role of the recipient site in the revascularization and incorporation of autogenous inlay bone grafts in the craniofacial skeleton. Clinical experience demonstrates that secondary complex cranial vault reconstruction performed with scarred avascular dura or poor soft-tissue coverage may undergo significant resorption, thus compromising the aesthetic outcome. This study was designed to determine the effect of isolating autogenous orthotopic inlay calvarial bone grafts from the surrounding dura and/or periosteum on graft revascularization, healing, and volume maintenance in the adult rabbit. Adult rabbits were randomized into four groups (n = 10 per group); in each rabbit, the authors created a circular, 15-mm in diameter, full-thickness cranial defect followed by reconstruction with an autogenous calvarial bone graft, which was replaced orthotopically and held with microplate fixation. Silicone sheeting (0.5 mm thickness) was used to isolate the dura (group II), the periosteum (group II), or both dura and periosteum (group IV) from the graft interface. No silicone was placed in group I. Animals were killed 10 weeks postoperatively, and calvaria were harvested to assess graft surface area, morphology, quantitative histology, fluorochrome staining, and revascularization. Grafts isolated from both the dura and periosteum exhibited significant decreases in total bone (cortical and trabecular) surface area, blood vessel count, and interface healing compared with nonisolated control grafts. Isolation of either the dura or periosteum significantly (p < 0.05) decreased blood vessel count but had no significant effect on interface healing. Isolation of the dura alone was associated with a significant (p < 0.05) decrease in graft cross-sectional surface area and dural cortical thickness compared with nonisolated control grafts, but this effect was not observed when the periosteum alone was isolated. Quantitative histology performed 10 weeks after surgery indicated that graft isolation was associated with increased marrow fibrosis and necrosis compared with nonisolated controls; it also demonstrated evidence of increased activity in bone remodeling (osteoblast and osteocyte count, new trabecular bone, and surface resorption). Triple fluorochrome staining suggested increased bone turnover in the nonisolated grafts compared with isolated grafts at 1 and 5 weeks postoperatively. This study demonstrates that isolating a rabbit calvarial inlay autogenous bone graft from the dura and/or periosteum results in significantly (p < 0.05) decreased revascularization, interface healing, and cross-sectional areas of amount of mature bone compared with nonisolated control grafts 10 weeks after surgery. At this time point, histologic examination demonstrates a paradoxical increase in bone remodeling in isolated bone grafts compared with controls. It is possible that the inhibition of revascularization results in a delayed onset of the remodeling phase of graft incorporation. However, in the model studied, it is not known whether the quantitative histologic and morphometric parameters measured in these isolated grafts exhibit a "catch-up" phenomenon at time points beyond 10 weeks after surgery. The results of this study emphasize the importance of a healthy recipient site in the healing and incorporation of calvarial bone grafts but stress the need for further investigation at later time points.