Preliminary experience with a dynamic resorbable fixation device for craniosynostosis surgery.

The advent of resorbable osteosynthesis material has revolutionized craniomaxillofacial surgery. The need to provide rigid bony fixation in the surgical treatment of craniofacial deformities has inspired an ongoing evolution of surgical innovations and implants. Stability of the plates has been improved, but the duration of their stability remains an ongoing problem. In infant craniofacial fixation, it is important to provide initial stability, but after 4 to 6 weeks, this is no longer required as the brain is rapidly expanding. Surgery was performed on 10 patients with sagittal suture synostosis with conventional suture resection, remodeling, and fixation with resorbable miniplate (PolyMax-RAPID) struts held in position with modeled resorbable pockets affixed to the neurocranium with resorbable screws placed across the resected suture between June 2004 and September 2008. All the patients presented a satisfactory aesthetic result without complications after at least 1-year follow-up. We present a further innovative method of craniofacial fixation in infants using resorbable plates as floating struts providing stability and at the same time controlled dynamic expansion of the cranial vault guided by brain growth.

Adaptive noninvasive assessment of intracranial pressure and cerebral autoregulation.

BACKGROUND AND PURPOSE: A mathematical model has previously been introduced to estimate noninvasively intracranial pressure (nICP). In the present multicenter study, we investigated the ability of model to adapt to the state of cerebral autoregulation (SCA). This modification was intended to improve the quality of nICP estimation and noninvasive assessment of pressure reactivity of the cerebrovascular system. METHODS: We studied 145 patients after severe head injuries or stroke. All patients had direct ICP, arterial blood pressure (ABP), and transcranial Doppler middle cerebral artery blood flow velocity (FV) monitored. The SCA was assessed by moving correlation (Mx index) of cerebral perfusion pressure (CPP=ABP-ICP) and cerebral blood flow velocity and correlation of ABP and ICP (PRx index). nICP was calculated from ABP and FV waveforms. When nICP was used instead of ICP, the SCA was continuously estimated, and the model was dynamically adapted to the SCA. RESULTS: High and moderate correlations between invasively (Mx, PRx) and noninvasively (nMx, nPRx) estimated autoregulation indexes were observed (Mx: R=0.90, P<0.001; PRx: R=0.62, P<0.001). Values of Mx and nMx indicated contradictory SCA in 4 of 167 evaluated recordings; values of PRx and nPRx were contradictory in 27 recordings. When the model was adapted to the SCA, the mean error of ICP estimation decreased significantly (P<0.005). CONCLUSIONS: Continuous adaptation of the model to SCA improves the accuracy of noninvasive estimation of ICP and ICP dynamics. The same model provides a noninvasive and continuous assessment of SCA.

Clinical acceptance and accuracy assessment of spinal implants guided with SpineAssist surgical robot: retrospective study.

STUDY DESIGN: Retrospective, multicenter study of robotically-guided spinal implant insertions. Clinical acceptance of the implants was assessed by intraoperative radiograph, and when available, postoperative computed tomography (CT) scans were used to determine placement accuracy. OBJECTIVE: To verify the clinical acceptance and accuracy of robotically-guided spinal implants and compare to those of unguided free-hand procedures. SUMMARY OF BACKGROUND DATA: SpineAssist surgical robot has been used to guide implants and guide-wires to predefined locations in the spine. SpineAssist which, to the best of the authors' knowledge, is currently the sole robot providing surgical assistance in positioning tools in the spine, guided over 840 cases in 14 hospitals, between June 2005 and June 2009. METHODS: Clinical acceptance of 3271 pedicle screws and guide-wires inserted in 635 reported cases was assessed by intraoperative fluoroscopy, where placement accuracy of 646 pedicle screws inserted in 139 patients was measured using postoperative CT scans. RESULTS: Screw placements were found to be clinically acceptable in 98% of the cases when intraoperatively assessed by fluoroscopic images. Measurements derived from postoperative CT scans demonstrated that 98.3% of the screws fell within the safe zone, where 89.3% were completely within the pedicle and 9% breached the pedicle by up to 2 mm. The remaining 1.4% of the screws breached between 2 and 4 mm, while only 2 screws (0.3%) deviated by more than 4 mm from the pedicle wall. Neurologic deficits were observed in 4 cases yet, following revisions, no permanent nerve damage was encountered, in contrast to the 0.6% to 5% of neurologic damage reported in the literature. CONCLUSION: SpineAssist offers enhanced performance in spinal surgery when compared to free-hand surgeries, by increasing placement accuracy and reducing neurologic risks. In addition, 49% of the cases reported herein used a percutaneous approach, highlighting the contribution of SpineAssist in procedures without anatomic landmarks.

Novel tumor antigens identified by autologous antibody screening of childhood medulloblastoma cDNA libraries.

Medulloblastoma is an embryonal childhood malignancy with poor prognosis. By screening 4 medulloblastoma cDNA expression libraries (SEREX) with autologous sera, 15 different antigens were identified. These antigens were encoded by 3 novel genes, genes of unknown function (KIAA0445, KIAA1853, KIAA0665, FLJ13942, HSPC213), a proto-oncogene (rab18), candidate tumor suppressor genes (BAP1, PRDM13) and genes encoding a motor protein (kinesin-2), a histone (H2A1.2), the ankyrin residue-rich nasopharyngeal cancer susceptibility protein (NZ16) and the transcription factor TZP, which is homologous to the tumor-associated antigens HCA58 and GLEA2. In a consecutive analysis of serum antibody titers and tumor load, a more than 10-fold increase in serum antibodies against PRDM13 preceded the clinical diagnosis of recurrent tumor growth in a patient with aggressive large cell medulloblastoma. When sera of pediatric patients with cancer (n = 40) and healthy controls (n = 40) were tested for humoral responses against the SEREX-defined antigens, 5 antigens were exclusively recognized by sera from cancer patients. These antigens included a novel rab18 gene product translated from mRNA sequences formerly described as 3' untranslated region. Humoral responses against 2 of the remaining 10 antigens were found preferentially in cancer patients. Antibodies against these antigens were detected in 8/40 and 12/40 cancer patients, respectively, but in only 1 healthy control. The 2 antigens were characterized by a tumor-specific deletion and a tumor-specific mutation, respectively. These findings indicate that the humoral immune response against medulloblastoma is directed against diverse antigens that may be useful as diagnostic markers or targets for immunotherapy.