Выбор объема субокципитальной декомпрессии в хирургии аномалии Киари I типа по данным интраоперационного ультразвукового исследования

There are numerous publications about the technical aspects of decompressive surgery for Chiari I malformation highlighting many variations of this procedure. Each approach has its followers. Bony decompression of the foramen magnum alone or with the removal of a portion of the posterior arch of C1, dural splitting with keeping arachnoid intact, and durotomy are described. Dural closure is done with various materials. We retrospectively reviewed foramen magnum decompression without dural repair (FMDWDR) following the technique used by Gardener and Williams as an option in pediatric patients with Chiari I malformation in terms of complication rate and clinical outcome. The surgical database of our unit identified 65 consecutive children who underwent FMDWDR surgery for Chiari I malformation between 2009 and 2016. The retrospective assessment included patient demographics, clinical data, surgical technique, revision rate, complications, and clinical outcome. Durotomy without repair was performed in 65 patients. Complications included aseptic meningitis and subdural hematoma respectively in three cases, intradiploic CSF collections in three patients, and CSF leaks in six children. The CSF leak rate has reduced dramatically after introducing a technical modification. Revision surgery was performed in seven cases. None of the patients was identified with postoperative hydrocephalus or infection. There was no mortality and no long-term surgical morbidity. In terms of clinical outcome, 52 patients reported postoperative improvement, 10 were clinically unchanged, and three noticed worsening of symptoms. Applying a "T"-shaped fascial incision which allows a watertight closure of the fascia FMDWDR is still a safe and effective treatment option for Chiari I malformation in children.

To examine the long-term effects of suboccipito-cervical decompression on an intention-to-treat basis in patients with Chiari I malformation (CMI). Twenty-four consecutive patients, 14 females and 10 males with a median age of 26 years, underwent decompressive surgery for CMI during 1998-2006. All patients were contacted by an independent examiner and asked to complete a questionnaire regarding headache, other neurological symptoms and negative impact of the disease on the daily life before and after surgery. The median follow-up time after surgery was 3.2 years (range 1.7-9.2 years). Twenty-three patients (96%) completed the questionnaire. On an intention-to-treat basis there was an improvement in headache in 75%, decreased associated neurological symptoms in 88% and less negative impact on daily life in 75% of the 24-operated patients. More than three-quarters of the patients still considered their situation improved at long-term follow-up after surgery. These results support surgical intervention in symptomatic Chiari I patients.

Iatrogenic syringomyelia has previously been described preoperatively due to space occupying lesions and postoperatively predominantly postspinal CSF drainage. Iatrogenic syringomyelia after cranial surgery is a rare entity. The purpose of this study is to review the current literature for iatrogenic syringomyelia following cranial surgery in children. We performed a systematic review in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and meta-analyses) guidelines. Using keywords "de novo," "acquired," "iatrogenic," "postoperative development," and "syringomyelia," we searched PubMed and Scopus databases. We paid particular attention to type of surgery, clinical presentation, management, and outcome. We also present a relevant case report, operated on at John Radcliffe Hospital, Oxford. The systematic literature review provided 19 cases of iatrogenic syringomyelia postcranial surgery in pediatric patients, in addition to our case report, resulting in a total of 20 cases reported. The patients' mean age at surgery preceding syringomyelia was 8.1years (range 0.1-17) with a female sex predilection (2.7:1). The mean time of manifestation of the iatrogenic syringomyelia after surgery was 5.7years (range 0.1-51), and the median time to presentation was 1.7years. Nine children had surgery for Chiari I malformation before formation of the syrinx, 8 patients underwent shunt surgery, 2 children had intracranial tumor surgery, and 1 patient had lambdoid and sagittal suturectomy for scaphocephaly before developing a syrinx. Surgery after the manifestation of the iatrogenic syrinx resolved the symptoms in 9 patients; in 8 patients, the symptoms partially resolved; and in 1 patient, the symptoms persisted. After surgery addressing the syrinx, it resolved in 5, decreased in size in 10, and remained unchanged in 2 of the patients. Iatrogenic syringomyelia after cranial surgery in pediatric patients occurs mainly after decompressive surgery for Chiari I malformation, shunt surgery, and less frequently following intracranial tumor surgery. Risk factors are postoperative intracranial scarring, shunt malfunction, and mass effect on the foramen magnum. Surgery addressing the iatrogenic syrinx seems to be effective in the majority of the patients in terms of clinical and radiological outcome.

The role of intraoperative neurophysiological monitoring (IONM) during surgery for Chiari I malformation has not been fully elucidated. Questions remain regarding its utility as an adjunct to foramen magnum decompression surgery, specifically, does IONM improve the safety profile of foramen magnum decompression surgery and can IONM parameters help in intraoperative surgical decision-making. This study aimed to describe a single institution experience of IOM during paediatric Chiari I surgery. The methodology comprised a retrospective review of prospectively collected electronic neurosurgical departmental operative database. Inclusion criteria were children under 16years of age who had undergone foramen magnum decompression for Chiari I malformation with IONM. In addition to basic demographic data, details pertaining to presenting features and post-operative outcomes were obtained. These included primary symptoms of Chiari I malformation and indications for surgery. MRI findings, including the presence of syringomyelia on pre-and post-operative imaging, were reviewed. Details of the surgical technique for each patient were recorded. Only patients with either serial brainstem auditory evoked potential (BAEP) and/or upper limb somatosensory evoked potential (SSEP) recordings were included. Two time points were used for the purposes of analysing IONM data; initial baseline before skin incision and final at the time of skin closure. Thirty-seven children underwent foramen magnum decompression (FMD) with IONM. Mean age was 10.5years (range 1-16years) with a male:female ratio 13:24. The commonest clinical features on presentation included headaches (15) and scoliosis (13). Twenty-four patients had evidence of associated syringomyelia (24/37 = 64.9%). A reduction in the SSEP latency was observed in all patients. SSEP amplitude was more variable, with a decrease seen in 18 patients and an increase observed in 12 patients. BAEP recordings decreased in 13 patients and increased in 4 patients. There were no adverse neurological events following surgery; the primary symptom was resolved or improved in all patients at 3-month follow-up. Resolution or improvement in syringomyelia was observed in 19/24 cases. Our data shows that FMD for Chiari malformation (CM) is associated with changes in SSEPs and BAEPs. However, we did not identify a definite link between clinical outcomes and IONM, nor did syrinx outcome correlate with IONM. There may be a role for IONM in CM surgery but more robust data with better-defined parameters are required to further understand the impact of IONM in CM surgery.

Background:Decompression of Chiari malformation is a common procedure in both pediatric and adult neurosurgery. Although the necessity for some bony removal is universally accepted, other aspects of Chiari surgery are the subject of debate. The most controversial points include the optimal amount of bony removal, the use of duraplasty (and the type of material), the need for subarachnoid dissection, and the need for tonsillar shrinkage.Material and Methods:We critically reviewed the literature to elucidate the risks and benefits of different graft types and to clarify optimal treatment options therein. Based on our search results, 108 relevant articles were identified. With specific inclusion and exclusion criteria, we noted three studies that directly compared two tlpes of dural substitutes in Chiari malformation surgery.Results:Our review did not support the superiority of either autologous or nonautologous grafts when duraplasty is employed. Our institutional experience, however, dictates that when the pericranium is available and of good quality, it should be utilized for duraplasty. It is non-immunogenic, inexpensive, and capable of creating a watertight closure with the dura.Conclusions:Discrepancies between the three comparative studies analyzed are likely attributable to increases in pericranial quality and thickness with maturity. Future randomized studies with large numbers and the power to resolve differences in the relatively low rates of complications in Chiari surgery are warranted.

Controversy of Surgical Treatment for Severe Cerebellar Infarction

Objective: Computer assisted planning of liver surgery based on preoperative computed tomography (CT) or magnetic resonance imaging (MRI) data can be an important aid to operability decisions and visualization of individual patients' 3D anatomy. A navigation system based on intraoperative 3D ultrasound may help the surgeon to precisely localize vessels, vascular territories or tumors. The preoperative planning must be transferred to the intraoperative ultrasound data and thus to the patient on the operating table. Due to deformations of the liver between planning and surgery, a fast non-rigid registration method is needed.Materials and Methods: A feature-based non-rigid registration approach based on the center-lines of the portal veins has been developed. The combination of an iterative closest point (ICP) approach and Multilevel B-Spline transformations offers a fast registration method. The vessels are segmented and their centerlines extracted from preoperative CT/MRI and intraoperative 3D Power-doppler ultrasound data. Anatomical corresponding points on the centerlines of both modalities are determined in each iteration of the ICP algorithm. The search for corresponding points is restricted to a given search radius and the direction of the vessels is incorporated.Results: The algorithm has been evaluated on two transcutaneous and one intraoperative clinical ultrasound data set from three different patients. Only a very few vessel segments were not assigned correctly compared to manual assignments. Using non-rigid transformations improved the root mean square target registration error of the vessels by approximately 3-5 mm.Conclusions: The proposed registration method is fast enough for clinical application in liver surgery. Initial accuracy results are promising and must be further evaluated, particularly in the operating room.

To explore the application value of preoperative multimodal image fusion technique in microvascular decompression (MVD) surgery via the suboccipital retrosigmoid approach. Comprehensive data of 13 patients with primary trigeminal neuralgia (TN) and 13 patients with hemifacial spasm (HFS) treated by MVD surgery via the suboccipital retrosigmoid approach at the Department of Neurosurgery in Zhuhai People's Hospital from January 2021 to December 2021 were retrospectively analyzed. Preoperatively, all patients underwent cranial thin-section computed tomography and magnetic resonance examinations. Three-dimensional (3D) digital images of the skull, brainstem, nerves, and blood vessels were constructed by the 3D-slicer software or RadiAnt DICOM Viewer, which were then applied to design the surgical approach and surgical plan. The multimodal image fusion results, clinical characteristics, intraoperative data, surgical outcomes, and complications of all patients were summarized. The 3D digital images after fusion reconstruction can vividly show the anatomical relationship between the skull, brainstem, nerves, and blood vessels and was helpful to tailor the surgical strategy. All 26 patients underwent a smooth surgery. During the surgery, the key points were accurately located, the corners of the transverse sinus and sigmoid sinus were completely exposed, and no venous sinus injury occurred in all 26 patients. The key point was approximately located at the top point of the digastric groove, 12.3±0.46mm vertically above and 6.3±0.6mm laterally to the Frankfurt horizontal plane. The average cranial opening time was 30.4 (±3.6) min, and the mean operating time was 104.7 (±12.1) min. The diameter of the bone window was about 2.0 cm-3.0cm, and the bone flap was restored. Among the 13 patients with primary TN, 12 (92.3%) exhibited complete relief of pain and 1 had significant relief. Complications of surgery included facial sensory numbness in 1 case, vertigo in 2 cases, and herpes at the corners of the mouth in 1 case. Of the 13 patients with HFS, 12 (92.3%) had complete relief of facial twitching symptoms and 1 had significant relief, and the complications included mild facial palsy in 2 (15.4%) cases and facial sensory numbness in another 2 (15.4%) cases. The mean follow-up time after surgery ranged from 6-16months, and 1 of 26 patients experienced recurrence of HFS during the follow-up period. Preoperative multimodal image fusion technology can provide adequate preoperative assessment for patients and assistance in designing surgical approaches, which is an important guideline for MVD surgery via the suboccipital retrosigmoid approach for primary TN and facial muscle spasm.

Computer based navigated surgery assists the spatial orientation of the surgeon. Our system registers preoperative data like CT or MR with intraoperative ultrasound data to get the coordinate transformation between the preoperative and the intraoperative data. With a surface volume registration we avoid a difficult surface segmentation in the ultrasound data. To prevent radial exposure and to get more details in the soft tissue the use of MR data for the operation planning is common. Extracting the bone surface in MR data is more difficult than in CT data because MR data has no normalized gray values. To register the ultrasound with the MR data at the knee we detected distinctive anatomic regions in the ultrasound data. We selected an adequate MR sequence in which we could segment the bone surface at the specific region. We evaluate the registration with 1000 random starting positions. 99.2% of the 1000 trails reached the optimum with an error less than 1 mm.

The authors describe a series of children with Chiari I malformation who presented with fulminating symptoms of "cerebellar fits" characterized by drop attacks with or without deterioration of consciousness, opisthotonic posturing, and varying degrees of respiratory compromise. A retrospective analysis was undertaken of the medical records of 47 consecutive patients undergoing surgery for symptomatic Chiari I malformations at Rainbow Babies and Children's Hospital. Thirteen (28%) of the 47 patients presented with complaints consistent with cerebellar fits. Before the correct diagnosis was made, nine (69%) of the 13 children had previously undergone evaluation with electroencephalography and/or electrocardicography and Holter monitoring because of suspected cortical epilepsy or cardiogenic syncope. In each of the 13 children magnetic resonance imaging demonstrated pegged cerebellar tonsils herniated below the foramen magnum. A deep indentation or blanched discoloration of the cerebellar tonsils was noted in five (38%) of these 13 patients at the time of surgery. Of patients with symptomatic Chiari I malformations, the mean degree of tonsillar herniation was significantly less for those in whom cerebellar fits occurred than those in whom they were absent (8.8 mm and 13.9 mm, respectively; p = 0.007). In only one of the patients with cerebellar fits was a syrinx present, and this was a small focal lower thoracic collection. Spells resolved after surgery in all patients who presented with cerebellar fits. Cerebellar fits may mimic other disorders such as cardiogenic syncope and epileptic seizures. The correct diagnosis may be delayed or the conditions may be misdiagnosed by those who fail to consider Chiari I malformation as a cause of drop attacks, abnormal extensor posturing, and apneic spells in children. The response to decompressive surgery in these patients is gratifying.

Intraoperative monitoring of corticospinal tracts in anterior cervical decompression and fusion surgery: Excitability differentials of lower extremity muscles

3D-Printer-Assisted Patient-Specific Polymethyl Methacrylate Cranioplasty: A Case Series of 16 Consecutive Patients

Introduction: Reperfusion injury of spinal cord “white cord syndrome” refers to acute neurological deterioration after decompressive spinal surgery without any reported intraoperative events. The postoperative appearance of diffuse hyperintense intramedullary areas in T2-weighted MRI is characteristic without any other pathological or compressive signs. The etiology may be due to sudden expansion of the cord after reperfusion of chronically ischemic areas leading to disruption of blood-spinal cord barrier. The incidence and risk factors of the syndrome are not well documented in the literature. Methods: This is a retrospective case series that included 150 patients with cervical spondylotic myelopathy who had undergone decompression surgery in our institution from 2017 to 2019. Patients’ demographics, clinical, imaging characteristics, intraoperative and postoperative data were collected and analysed. Results: In this study, we documented 7 cases of this syndrome. We found that advanced age, chronic hypertension, pre-existing cord signal in MRI and long history of symptoms may be risk factors for this syndrome. Conclusion: Early diagnosis and prompt treatment of this syndrome with steroids and physical therapy may lead to initial improvement. Awareness of the surgeons about this syndrome should be increased and identifying its risk factors is very important for patients counseling.

The objective of decompressive surgery for Chiari I malformation is to create additional space to accommodate the ectopic cerebellar tonsils and to improve the flow of cerebrospinal fluid. To the best of our knowledge, we report the first case of a patient with previous Chiari I decompression presenting 5years after surgery at the same time as an intraosseous C2 and a suboccipital intradiploic cerebrospinal fluid accumulation. Because of the progressive nature of the C2 cerebrospinal fluid collection causing bone destruction, surgical management was indicated. To avoid the erosion of the bone, we propose that the iatrogenic exposure of the diploe and the vertebral spongiosa that may come into contact with the cerebrospinal fluid should be sealed off with bone wax or a similar material.

ObjectiveCombined with different configuration types of syringomyelia, to analyze the correlation between syrinx resolution and changes in cervical sagittal alignment following Foramen magnum and Magendie dredging (FMMD) for syringomyelia associated with Chiari I malformation (CM-I), and to further explore the respective relationship with clinical outcome.MethodsA consecutive series of 127 patients with CM-I and syringomyelia who underwent FMMD in our center met the inclusion criteria of this study. Their clinical records and radiologic data were retrospectively reviewed. The Japanese Orthopedic Association (JOA) scoring system and the Chicago Chiari Outcome Scale (CCOS) were used to evaluate the surgical efficacy. The phenotypes of syringomyelia and the clinical characteristics of the patients were analyzed according to grouping by cervical curvature at baseline.ResultsThe preoperative straight or kyphotic cervical alignment is more common in the moniliform syrinx. After surgery, the syrinx resolution and cervical sagittal realignment in the moniliform group are more obvious, and the corresponding prognosis is relatively better. Spearman correlation analysis showed that the ΔS/C ratio (the change ratio of syrinx/cord) was positively correlated with the CCOS (p = 0.001, r = 0.897) and ΔC2–7A (the change of lower cervical angle) (p = 0.002, r = 0.560). There was also a correlation between the ΔJOA score (the change rate of the JOA score) and ΔC2–7A (p = 0.012, r = 0.467).ConclusionAfter decompression surgery, syrinx resolution may coexist with the changes in the subaxial lordosis angle, especially for syrinx in moniliform type, and the relationship between syrinx resolution and cervical sagittal realignment might be valuable for evaluating the surgical outcome.