The use of patient specific polyetheretherketone implants for reconstruction of maxillofacial deformities.

PURPOSE: The aim of this study was to evaluate polyetheretherketone (PEEK) as a patient-specific implant (PSI) material in maxillofacial reconstructive surgery. MATERIALS AND METHODS: The retrospective study included a cohort of 24 patients who underwent maxillofacial surgery using PEEK PSIs. Each patient underwent preoperative multislice computed tomography (CT) with 0° tilt of gantry. Based on the CT scan, the PEEK PSIs were planned and manufactured using three-dimensional (3D) modeling and computer-aided design/computer-aided manufacturing (CAD/CAM) techniques. All procedures were performed under general anesthesia. Implants were placed intraorally, extraorally or through subciliary, transconjuctival or coronal incisions. RESULTS: In 22 of 24 cases, the PEEK PSI fit well without adjustments. Although the fit to the surrounding bone was perfect in almost all of the cases, the outer contour of the PSI was modified in nine cases before fixation. However, intraoperative implant modification did not affect the infection rate. In two cases, postoperative wound dehiscence and infection needed additional treatment and healed without removal of the implants. CONCLUSION: The follow-up data in this study showed good outcomes with reliable results for PSI made of PEEK in the maxillofacial region.

Mechanical analysis of cranial distractor attachment with three different resorbable fixation systems.

Distraction osteogenesis (DO) has become increasingly popular to correct craniosynostosis. Disadvantages of DO include the secondary operation needed for device removal and titanium screw related dura injury. To reduce invasiveness of the secondary device removal operation and to overcome titanium-related problems, fixation of the cranial distractor with resorbable materials is a potential alternative. New resorbable fixation methods, such as ultrasound-activated pins (UAPs) or heat-activated pins (HAPs), allow faster attachment on thinner bone than conventional resorbable screws (CRSs) since tapping is not required. However, resorbable materials are designed to be attached with a resorbable plate, not with a titanium distractor. We evaluated the suitability of CRSs, HAPs and UAPs for the cranial distractor fixation in a laboratory setting with a mechanical testing machine. Fracture tests were conducted in two directions with respect to the longitudinal axis; vertical i.e. axial pull-out strength, and horizontal i.e. shear strength. Mean maximum pull-out strength for CRS, HAP and UAP was 48.9 N, 32.5 N and 14.7 N, respectively. Mean maximum shear strength for CRS, HAP and UAP was 40.8 N, 77.9 N and 38.9 N, respectively. According to our in vitro tests, the cranial distractor attachment with four CRSs or six HAPs per footplate would provide sufficient fixation stability.

Force measurements during posterior calvarial vault osteodistraction: A novel measurement method.

Posterior calvarial vault osteodistraction (PCVO) has become increasingly popular in the correction of craniosynostosis. When compared to cranioplasty, PCVO offers a shorter, less invasive operation, greater intracranial volume advancement and a lower rate of relapse. In general, distraction protocols are based primarily on clinical observations rather than systematic research. Faster distraction protocols may reduce complications. However, distraction protocols producing higher forces can increase complications. Thus, we need to understand these forces in order to improve distraction protocols and devices. We developed a force measurement method that can be used on PCVO devices. Here, we present preliminary data about the forces developed during PCVO. We measured the forces in four bicoronal craniosynostosis patients during PCVO. We observed a linear-like trend between the force increase and the distraction distance within distraction sessions. We also observed a step-wise force increase between distraction sessions and found that the distraction force relaxed rapidly shortly after the distraction session. The mean maximum pre-distraction force for one distracter was 20.4 N, while the mean maximum end-distraction force for one distracter was 57.6 N. Our data suggests that current treatment protocols might be re-evaluated favouring shorter distraction distances and more frequent distraction sessions.

Promoting ossification of calvarial defects in craniosynostosis surgery by demineralized bone plate and bone dust in different age groups.

Correction of calvarial defects after calvarial vault reconstruction (CVR) is challenging in craniosynostosis patients of advanced age and typically employs autologous bone. Demineralized bone matrix (DBM) is a potential alternative material for autologous bone, but its use has not been extended to correct calvarial defects. CVR patients operated at the Department of Plastic Surgery, Helsinki University Hospital, during 2008-2010 were retrospectively reviewed. Inclusion criteria of the study were CVR patients who received DBM plate, with or without bone dust, on calvarial defects and who had suitable uncovered defect on the contralateral side as control. This study included 17 craniosynostosis and one positional plagiocephaly patient, whose mean age was 6.9 years (range 0.9-19 years). The mean follow-up time was 5.6 years. The fusion degree of all defects was measured from 1 week to 1 year postoperatively using three-dimensional computed tomography (3D CT) images by the OsiriX© method. Medical records were reviewed for DBM-related complications. A total of 26 defects were covered with a DBM plate (mean area 11.1 cm2) and 26 control defects were identified (mean area 7.8 cm2). The mean fusion degree of the DBM defects was 74% and 54% for the controls (p < 0.001). The mean fusion degree of nine DBM defects that lacked bone dust deposition was 66% and 55% for the nine controls (p < 0.059). The difference between the DBM and control defects was statistically significant for patients older than 30 months (p < 0.03). No DBM-related complication was observed. DBM plate is a safe and useful material to promote ossification in calvarial defects in CVR. Furthermore, DBM appears to be more effective in older patients (>30 months) than in younger patients or when used with bone dust.

Perinatal features and rate of cesarean section in newborns with non-syndromic sagittal synostosis.

PURPOSE: The purpose of this study was to evaluate perinatal features and the rate of cesarean section in children with non-syndromic sagittal synostosis and to compare these with the official statistics. METHODS: The birth data of 36 consecutive children (25 boys) operated on using cranial vault remodeling because of primary sagittal synostosis were analyzed retrospectively from hospital records. The children were born between 2007 and 2011, and the surgery was performed before the age of 1 year. The official statistics of all Finnish newborns from the year 2010 (n = 61 371) were used as a reference. Chi-square and Fisher's exact tests were used in statistical analyses. RESULTS: The average gestational age of the newborns with sagittal synostosis was 39.8 weeks (reference 39.7 weeks). The average birth weight was 3565.8 g (3540 g) for boys and 3197.2 g (3427 g) for girls, and the average lengths at birth are 51 cm (50.4 cm) and 49.4 cm (49.6 cm), respectively. The average head circumference was 36 cm for both sexes (35.2 and 34.6 cm for reference boys and girls). The mean age of mothers was 30.5 years (30.1 years). The rate of cesarean section was significantly increased 30.5 % (reference 16.6 %), and the rate of suction cup delivery was increased 13.9 % (9 %). In addition, a prolonged or difficult delivery was reported in three childbirths. CONCLUSION: Newborns with non-syndromic sagittal synostosis appear to be of average birth size and gestational age. The incidences of perinatal complications and cesarean sections were increased with problems occurring in more than half of the childbirths.

Asymmetric laterality of Chiari type I malformation in patients with non-syndromic single-suture craniosynostosis.

BACKGROUND: Chiari type I malformation is a frequent incidental finding commonly associated with craniosynostosis. However, there seems to be a paucity of literature concerning the asymmetry of tonsillar herniation in patients with non-syndromic single-suture craniosynostosis. METHODS: To study the asymmetry in this cohort, measurements of the right and left tonsils were made from sagittal images from both pre-operative and post-operative images from 11 patients with non-syndromic single-suture craniosynostosis. RESULTS: Pre-operatively, the mean difference between the caudal descent of all tonsils ranged from 0 to 7 mm, with a mean difference between sides of 2.45 mm. In three cases, cerebellar tonsils were symmetrically herniated. Post-operatively, the mean difference between caudal descent of all tonsils ranged from 0 to 4 mm, with a mean difference between sides of 1.45 mm. Four were symmetrically herniated. In patients with non-syndromic single-suture craniosynostosis, the tonsillar herniation is asymmetric in the majority of cases. CONCLUSIONS: Asymmetry of cerebellar tonsil herniation is a frequent finding in this cohort. The right tonsil is more inferiorly located in majority of cases, with predominance to the synostotic suture side in asymmetric craniosynostosis cases.

Morphometric comparison of foramen magnum in non-syndromic craniosynostosis patients with or without Chiari I malformation.

BACKGROUND: In order to compare the morphometry of foramen magnum (FM) in a matched-pair study, in children with non-syndromic craniosynostosis with and without Chiari I malformation (CMI), both brain magnetic resonance (MRI) and multidetector computed tomography (MDCT) images were utilized. METHODS: Brain MR images were retrieved from the Helsinki University Hospital Picture Archiving and Communications System to identify patients with CMI during 1.1.2004 to 31.3.2009. Age-, gender-, and craniosynostosis-matched controls were retrieved from the same cohort. Morphometric analysis of FM was carried out. RESULTS: Seven patients with non-syndromic craniosynostosis with CMI were recorded. In CMI patients, the absolute anteroposterior length was 33.4 mm as compared to 36.7 mm in controls (p = 0.023). The mean width was 28.1 and 29.9 mm (p = 0.29), and the cross-sectional area was 654.1 and 764.9 mm(2) (p = 0.11) in CMI and controls, respectively. In CMI patients, the relative anteroposterior length of the FM was, on average, 91 % of the control's measurements. On average, the width was 95 % and the cross-sectional area was 88 % of the control's results. CONCLUSIONS: In pediatric non-syndromic craniosynostosis patients, a statistically significant reduced anteroposterior diameter of the FM is found in patients with an adjacent CMI as compared to their age-, gender-, and type-matched controls of craniosynostosis.

The evolution of cerebellar tonsillar herniation after cranial vault remodeling surgery.

PURPOSE: We sought to examine the pre- and postoperative changes of cerebellar tonsillar herniation by MR imaging in asymptomatic pediatric patients with nonsyndromic, single-suture craniosynostosis (N-SSSC), who underwent cranial vault remodeling surgery without suboccipital decompression. We required cerebellar tonsillar herniation through foramen magnum ≥3 mm for Chiari type I malformation (CMI). We hypothesized that the increase of intracranial volume by cranial vault remodeling would correct the asymptomatic CMI. METHODS: We identified 9 patients among 121 N-SSSC children undergoing craniofacial surgery from January 2004 to October 2010 with CMI. However, two of them were excluded from the study due to missing postoperative MR images. In the final study population, six were males, five were scaphocephalic, while two were diagnosed with coronal synostosis. RESULTS: In four of the cases, the CMI was decreased in postoperative MR imaging varying from 6 to 12 mm. In three cases, the herniation remained stable. The median change of cerebellar tonsillar herniation was -6.5 mm. CONCLUSIONS: We conclude that asymptomatic patients with existing CMI may benefit from cranial vault remodeling surgery alone increasing the intracranial volume.

Brain anomalies in 121 children with non-syndromic single suture craniosynostosis by MR imaging.

INTRODUCTION: The aim of this study was to evaluate prevalence of intracranial abnormalities in children with non-syndromic single suture craniosynostosis scheduled for cranial vault remodelling surgery using pre-operative magnetic resonance imaging. PATIENTS AND METHODS: A retrospective analysis of brain magnetic resonance imaging studies of 129 non-syndromic single suture craniosynostosis children undergoing craniofacial surgery between January, 2004-October, 2010 was conducted. Statistical analysis was performed for child, maternal and sibling related predisposing factors for abnormal brain magnetic resonance imaging findings. The mean age of these 121 patients at the time of imaging was 21.6 months. The majority, 78% were males and 74% of the patients were scaphocephalic. RESULTS: In 18 (15%) patients abnormal brain findings were noted. The most common finding was Chiari 1 malformation in 11 (9%). Chiari 1 malformation comprised over half (61%) of the brain anomalies identified. None of these findings required any additional surgical procedures. None of the statistical analysis reached statistical significance. CONCLUSIONS: Brain anomalies in connection with non-syndromic single suture craniosynostosis patients seem to be a coincidental event. We did not establish any specific craniosynostosis form to be regularly associated with abnormal brain magnetic resonance imaging findings. The routine use of pre-operative magnetic resonance imaging in non-syndromic single suture craniosynostosis patients seems to be of limited value in the search for associated intracranial malformations necessitating additional interventions.

A second radioisotope injection enhances intraoperative sentinel node identification in breast cancer patients without visualized nodes on preoperative lymphoscintigraphy.

PURPOSE: To evaluate the influence of a second radioisotope injection on the intraoperative success rate in patients with non-visualized axillary sentinel nodes (SN). MATERIAL AND METHODS: Altogether, 534 consecutive breast cancer patients with lymphoscintigraphy (LS) and SN biopsy and were included. An intratumoral injection of 99mTc-labeled human albumin colloid with a median dose of 93 MBq was applied. Forty-two of the 80 patients without axillary hot spots on LS received a second tracer injection with a median dose of 70 MBq. RESULTS: The visualization rate of axillary SN was 454/534 (85%). The intraoperative SN identification rate was 97% in patients with and 69% in patients without visualized SN in the axilla (P<0.00005), but the success rate was higher (88%) with a second radioisotope injection than without it (47%; P<0.0002). CONCLUSION: The failure rate in intraoperative SN identification was minimized using a second radioisotope injection in patients without axillary SN on LS.

Adjusting the radioisotope tracer dose according to the body mass index does not enhance the visualization of axillary sentinel lymph nodes.

PURPOSE: To investigate whether the visualization of axillary sentinel nodes (SN) in the lymphoscintigraphy (LS) can be enhanced by adjusting the amount of radioactivity in accordance with the patient's body mass index (BMI). MATERIAL AND METHODS: Group I consisted of 356 consecutive breast cancer patients who underwent LS and SN biopsy after a single, intratumoral radioactive tracer injection with a median dose of 92 MBq. In group II (178 consecutive patients), the dose of the tracer was adjusted according to BMI; 80, 100, or 140 MBq. RESULTS: The visualization rate of axillary SN was 86% in group I and 83% in group II (P = 0.303). In patients with BMI >30 with visualized axillary SN, the median number of SN was 1 (1-4) in group I and 3 (1-7) in group II (P = 0.002). CONCLUSION: Adjusting the tracer dose in accordance with patient BMI did not enhance the visualization rate of axillary SN in LS.

The prevalence of axillary lymph-node metastases in patients with pure tubular carcinoma of the breast and sentinel node biopsy.

AIMS: We aimed to evaluate the prevalence of and the risk factors for axillary lymph-node metastases in pure tubular carcinoma (PTC) of the breast. The role of axillary staging and treatment in PTC was also evaluated. METHODS: Between March 2001 and August 2004, 33 PTC patients underwent sentinel node (SN) biopsy as a part of their surgical treatment. Level I/II axillary clearance was carried out in case of tumour positive SN findings. To confirm the correct histological diagnosis (PTC, >90% tubular component), the breast tumours were reviewed by an expert breast pathologist. RESULTS: The SN were successfully harvested in all patients. The median number of SN harvested in the axilla was 3 (range 1-10). Nine (27%) of the 33 patients had axillary nodal metastases. The median number of metastatic nodes was 1 (range 1-3). The median size of the SN metastases was 0.5 mm (mean 1.7 mm, range 0.4-5 mm). In six patients, micrometastases were the only tumour positive SN findings. The median histological tumour size was similar, 9 vs 10mm, in patients with or without axillary metastases. The median patient age was 54 (range 44-71) and 57 (range 39-80) years, respectively. After the histopathological review, six of the 27 patients with true PTC had axillary metastases. The review did not significantly change the risk factors for axillary metastases. CONCLUSIONS: Every fourth PTC patient has axillary lymph-node metastases, most often micrometastases. SN biopsy appears as a feasible method for axillary staging in PTC patients.

Antibodies against oxidised low-density lipoprotein in juvenile chronic arthritis.

Enhanced lipid peroxidation, reported to take place in rheumatoid joints and suggested to play a significant role in joint inflammation, led us to study the occurrence of antibodies against oxidised low-density lipoprotein (Ox-LDL Ab) in patients with juvenile chronic arthritis. Enzyme-linked immunosorbent assay was used to detect Ox-LDL Ab and antiphospholipid antibodies (aPL Ab) in sera from 84 patients and 91 controls. Elevated levels of Ox-LDL Ab were found in 14 patients (17%) as opposed to 4 controls (4%; p < 0.01). Similarly, 14 patients had an elevated aPL Ab level and a fairly good correlation between Ox-LDL Ab and aPL Ab (r = 0.52) existed in the patients. The increased frequency of elevated levels of Ox-LDL Ab may reflect lipid peroxidation occurring in rheumatoid joints but crossreactivity with aPL Ab for the induction of Ox-LDL Ab cannot be excluded.

Can the supply and demand for plasma-derived products ever be reconciled? Self-sufficiency from the viewpoint of a blood transfusion service.

Sufficiency is the balance between supply and demand. The problems of estimating future demands and of maintaining adequate supplies of blood for the preparation of blood products, will be discussed from the viewpoint of a well-established blood transfusion service.