Acute respiratory arrest following partial suboccipital cranioplasty for cerebellar ptosis from Chiari malformation decompression

Enhanced Ionic Polymer-Metal Composites with Nanocomposite Electrodes for Restoring Eyelid Movement of Patients with Ptosis

The present study aims to use enhanced ionic polymer-metal composites (IPMC) as an artificial muscle (a soft-active actuator) to restore eyelid movement of patients with ptosis. The previous eyelid movement mechanisms contained drawbacks, specifically in the lower eyelid. We used finite element analysis (FEA) to find the optimal mechanism among two different models (A and B). In addition to common electrodes of IPMC (gold and platinum), the bovine serum albumin (BSA) and microcrystalline cellulose (MCC) polymers, with optimal weight percentages of carbon nanotube (CNT) nanofiller, were also utilized as non-metallic electrodes to improve the efficiency of the IPMC actuator. In both models, IPMC with nanocomposite electrodes had higher efficiency as compared to the metallic electrodes. In model A, which moved eyelids indirectly, IPMC with MCC-CNT electrode generated a higher force (25.4%) and less stress (5.9 times) as compared to IPMC with BSA-CNT electrode. However, the use of model A (even with IPMCs) with nanocomposite electrodes can have limitations such as possible malposition issues in the eyelids (especially lower). IPMC with MCC-CNT nanocomposite electrode under model B, which moved eyelids directly, was the most efficient option to restore eyelid movement. It led to higher displacements and lower mechanical stress damage as compared to the BSA-CNT. This finding may provide surgeons with valuable data to open a window in the treatment of patients with ptosis.

"Stealth cranioplasty:" A novel endeavor for symptomatic adult Chiari I patients with syringomyelia: Technical note, appraisal, and philosophical considerations

Aim and Objective:

In this article, we describe a novel technique of reconstruction of posterior fossa by cranioplasty with use of preshaped titanium mesh following posterior fossa decompression (PFD) for Chiari malformation type I (CMI) with syringomyelia (SM) in symptomatic adults.

Materials and Methods:

Eleven patients underwent limited PFD and expansive cranioplasty with preshaped titanium mesh, what we term as “Stealth Cranioplasty” (SCP), following arachnoid preserving duraplasty (APD) and hexagonal tenting of the duraplasty with the cranioplasty (HTDC) for the management of symptomatic adult CMI with SM. All these patients had syringes extending from 3 to >10 vertebral levels.

Results:

Seven male and four female symptomatic CMI adult patients, between age ranges of 22 and 44 years (mean 29.45 years), presented with different neurological symptoms related to CMI and SM for 6–84 months (mean 37.09 months). All the patients underwent PFD, APD followed by SCP and HTDC and were followed up for 7–54 months (mean 35.90 months). Of 11 patients, 8 patients improved according to the Chicago Chiari Outcome Scale (CCOS) with score of 13–15 while 3 patients remained unchanged with CCOS of 12, and there was no worsening. There was no complication related to Chiari surgery in any of the patients. All the patients had good reestablishment of cisterna magna. Two patients had marked reduction of syrinx while eight patients had moderate-to-mild reduction and one patient had no change of syrinx. None of the patients needed redo surgery.

Conclusion:

SCP is an effective, fruitful, and cost-effective technique for the management of symptomatic adult CMI with SM. This technique has the advantages of preventing complications and recurrences in addition to the improvement of symptoms by addressing the basic pathology.

Chiari Syndrome and Respiratory Failure

Background:

Patients with failed extubation requiring reintubation have increased morbidity and mortality. This situation may reflect the severity of the underlying disorder or may reflect an undiagnosed condition that was not apparent at the time of the initial intubation.

Methods:

Case report and literature review.

Results:

A 49-year-old man developed acute hypercapneic respiratory failure during an episode of community-acquired pneumonia. This patient failed extubation 4 times. Routine neurological evaluation, including computed tomography of the head, was within normal limits. A magnetic resonance imaging revealed a severe Chiari malformation type I. The patient eventually required tracheostomy and prolonged mechanical ventilation. We identified 28 cases with Chiari malformations (CM) in the medical literature, who presented with respiratory failure. The mean age was 29.5 years, 46% of the cases were male, 50% had an associated syringomyelia, and 64% required a decompressive surgery. Twenty-five percent had recurrent symptoms postsurgery.

Conclusions:

Patients with CMs can have repeated extubation failures. Some of these patients have normal neurological examinations and studies and are not identified until they have an MRI study. Clinicians need to consider this possibility in patients who are difficult to wean.

Chiari type I malformation in children

The diagnosis of Chiari type I malformation (CIM) is more and more frequent in clinical practice due to the wide diffusion of magnetic resonance imaging. In many cases, such a diagnosis is made incidentally in asymptomatic patients, as including children investigated for different reasons such as mental development delay or sequelae of brain injury. The large number of affected patients, the presence of asymptomatic subjects, the uncertainties surrounding the pathogenesis of the malformation, and the different options for its surgical treatment make the management of CIM particularly controversial.This paper reports on the state of the art and the recent achievements about CIM aiming at providing further information especially on the pathogenesis, the natural history, and the management of the malformation, which are the most controversial aspects. A historial review introduces and explains the current classification. Furthermore, the main clinical, radiological, and neurophysiological findings of CIM are described to complete the picture of this heterogeneous and complex disease.

The effects of posterior fossa decompressive surgery in adult patients with Chiari malformation and sleep apnea

Object

One of the feared consequences of craniovertebral junction diseases is apnea. Although several cases of patients with central apnea have been described, obstructive sleep apnea has been identified as the most frequent manifestation of sleep respiratory disorder. Neuronal involvement may be responsible for both central and obstructive apneas. The objective of this work was to study the effect of posterior fossa decompressive surgery on respiratory parameters during sleep in patients with craniovertebral junction malformations and breathing-related sleep disorders.

Methods

In this study, prospectively enrolled consecutive symptomatic adult patients were monitored with full-night polysomnography before and after surgical decompression of the cranial posterior fossa.

Results

Of the 25 patients who were evaluated, 68% received a diagnosis of sleep apnea. After surgery, the mean number of respiratory events decreased from 180.70 to 69.29 (p = 0.005); the mean number of obstructive events decreased from 107.37 to 60.58 (p = 0.01); and the mean number of central events decreased from 38.45 to 8.05 (p = 0.01). The mean preoperative apnea/hypopnea index decreased from 26.68 to 12.98 (p = 0.06), and the mean central apnea index decreased from 13.81 to 1.68 (p = 0.01).

Conclusions

Decompressive surgery in patients with craniovertebral junction malformations resulted in decreased respiratory events during sleep, lowered sleep fragmentation, and enhanced the sleep apnea index in a significant number of patients. The effect was more pronounced in patients with central apnea.