Acute respiratory failure and sleep-disordered breathing in Arnold–Chiari malformation

Congenital Central Hypoventilation Syndrome: A Case Report

Congenital central hypoventilation syndrome (CCHS) is a rare cause of apnea and hypoventilation requiring long-term multidisciplinary care. In this article, we report the case of a two-month-old female child who presented with recurrent apnea and cyanosis, requiring long-term ventilation. After ruling out other common causes of apnea like sepsis, metabolic disorders, and neuromuscular disorders, a genetic study was done, which confirmed the diagnosis of CCHS. The child was discharged on home oxygen therapy, and the parents were counseled about genetic testing and informed about the prognosis and requirement for home ventilation therapy, as well as parental testing.

Evaluation of risk factors for sleep-disordered breathing in dogs

BACKGROUND

Brachycephalic dogs display sleep-disordered breathing (SDB). The risk factors for SDB remain unknown.

OBJECTIVES

To identify risk factors for SDB. We hypothesized that brachycephaly, increasing severity of brachycephalic obstructive airway syndrome (BOAS), excess weight, and aging predispose to SDB.

ANIMALS

Sixty-three privately owned pet dogs were prospectively recruited: 28 brachycephalic and 35 normocephalic (mesaticephalic or dolicocephalic) dogs.

METHODS

Prospective observational cross-sectional study with convenience sampling. Recording with the neckband was done over 1 night at each dog's home. The primary outcome measure was the obstructive respiratory event index (OREI). Body condition score (BCS) was assessed, and BOAS severity was graded for brachycephalic dogs.

RESULTS

Brachycephaly was a significant risk factor for high OREI value (ratio of the geometric means 5.6, 95% confidence interval [CI] 3.2-9.9; P < .001) but aging was not (1.1, 95% CI 1.0-1.2; P = .2). Excess weight, defined as a BCS of over 5/9, (3.5, 95% CI 1.8-6.7; P < .001) was a significant risk factor. In brachycephalic dogs, BOAS-positive class (moderate or severe BOAS signs) was a significant risk factor (2.5, 95% CI 1.1-5.6; P = .03).

CONCLUSIONS AND CLINICAL IMPORTANCE

Brachycephaly decreases welfare in a multitude of ways, including disrupting sleep. Brachycephaly, increasing severity of BOAS and excess weight are risk factors for obstructive SDB.

Delayed post-operative aggravation of sleep related disturbances in patients of basilar invagination with Chiari malformation: case report and review of the literature

Sleep apnoea is common in patients with Basilar Invagination with Arnorld Chiari Malformation (ACM). Various studies have shown its incidence in the range of 60-70% among such patients. Most of the studies have shown improvement in sleep disturbances after decompressive surgeries for Chiari Malformations. There is no report of postoperative deterioration due to sleep apnoea in these patients. Authors report two cases of basilar invagination associated with ACM and Platybasia, who deteriorated probably due to worsening of pre-existing sleep disorders on 3rd and 7th postoperative days after their surgeries, despite clinico-radiological improvements during their early post-operative courses. Authors discuss literature related to sleep apnoea in basilar invagination associated with Chiari Malformations and share precautions, which are relevant and should be undertaken in such patients especially during early post-operative periods to avoid alarming complication which may occur even in experienced hands.

Description of a novel method for detection of sleep-disordered breathing in brachycephalic dogs

BACKGROUND

Sleep-disordered breathing (SDB), defined as any difficulty in breathing during sleep, occurs in brachycephalic dogs. Diagnostic methods for SDB in dogs require extensive equipment and laboratory assessment.

OBJECTIVES

To evaluate the usability of a portable neckband system for detection of SDB in dogs. We hypothesized that the neckband is a feasible method for evaluation of SDB and that brachycephaly predisposes to SDB.

ANIMALS

Twenty-four prospectively recruited client-owned dogs: 12 brachycephalic dogs and 12 control dogs of mesocephalic or dolicocephalic breeds.

METHODS

Prospective observational cross-sectional study with convenience sampling. Recording was done over 1 night at each dog's home. The primary outcome measure was the obstructive Respiratory Event Index (OREI), which summarized the rate of obstructive SDB events per hour. Additionally, usability, duration of recording, and snore percentage were documented.

RESULTS

Brachycephalic dogs had a significantly higher OREI value (Hodges-Lehmann estimator for median difference = 3.5, 95% confidence interval [CI] 2.2-6.8; P < .001) and snore percentage (Hodges-Lehmann estimator = 34.2, 95% CI 13.6-60.8; P < .001) than controls. A strong positive correlation between OREI and snore percentage was detected in all dogs (rs = .79, P < .001). The neckband system was easy to use.

CONCLUSIONS AND CLINICAL IMPORTANCE

Brachycephaly is associated with SDB. The neckband system is a feasible way of characterizing SDB in dogs.

Soft tissue density within the foramen magnum, a predictor for surgical intervention in pediatric patients with Chiari malformation type I

OBJECTIVE

Chiari malformation type I (CMI) is diagnosed as herniation of the cerebellar tonsils by at least 5 mm below the foramen magnum. However, the degree of tonsillar herniation is a poor predictor of the need for decompression surgery. Exploration for an alternative morphological predictor for surgical intervention could provide greater insight into the development of an appropriate treatment plan for these patients. To investigate this issue, the authors calculated the soft tissue density within the foramen magnum as a measure of impaction of the cerebellar tonsils. Soft tissue density within the foramen magnum and degree of tonsillar herniation were then assessed for their correlation with the need for surgical intervention.

METHODS

The authors conducted a retrospective, longitudinal chart review of pediatric patients with CMI. Those who had undergone surgical intervention were considered symptomatic and those who had been treated conservatively, as asymptomatic. Soft tissue density was found by dividing the soft tissue occupancy of the foramen magnum (brainstem and cerebellar tonsils) by the total area of the bony foramen magnum. The predictive value of these two measurements for the need of surgery was determined.

RESULTS

Of the 465 patients seen for CMI at the authors' institution between July 1, 2011, and May 31, 2017, 80 underwent surgical intervention and 385 were asymptomatic. The average tissue density was significantly greater in the surgical group than in the asymptomatic group (83.3% and 78.6%, respectively, p < 0.0001). The average tonsillar descent for surgical patients was 10.8 mm compared to 9.8 mm for asymptomatic patients (p = 0.140). The point-biserial correlation coefficient was assessed, and soft tissue density was found to positively correlate with the need for surgical intervention (rpb = 0.199, p = 0.0001), whereas tonsillar herniation did not correlate with the need for surgery (rpb = 0.083, p = 0.115). Additionally, the degree of tonsillar herniation did not correlate with soft tissue density (r = 0.09), indicating that soft tissue density is an independent morphological parameter.

CONCLUSIONS

The study findings suggest that the need for surgical intervention in CMI patients is positively correlated with increasing soft tissue density within the foramen magnum, whereas the degree of tonsillar herniation did not show a correlation with the need for surgical intervention. Additionally, soft tissue density is a factor independent of the degree of tonsillar herniation. Further investigation of tissue density within the foramen magnum is needed in the hope of discovering a clinically applicable parameter that would indicate a need for surgical intervention in patients with CMI.

The impact of imposed delay in elective pediatric neurosurgery: an informed hierarchy of need in the time of mass casualty crisis

SARS-CoV-2 COVID-19, coronavirus, has created unique challenges for the medical community after national guidelines called for the cancellation of all elective surgery. While there are clear cases of elective surgery (benign cranial cosmetic defect) and emergency surgery (hemorrhage, fracture, trauma, etc.), there is an unchartered middle ground in pediatric neurosurgery. Children, unlike adults, have dynamic anatomy and are still developing neural networks. Delaying seemingly elective surgery can affect a child's already vulnerable health state by further impacting their neurocognitive development, neurologic functioning, and potential long-term health states. The purpose of this paper is to demonstrate that "elective" pediatric neurosurgery should be risk-stratified, and multi-institutional informed guidelines established.

Acute deterioration of adults with Chiari I malformation associated with extensive syrinx

Background: Chiari I malformation (CMI) is usually a chronic disorder, although it may also present as a life-threatening condition with need for urgent decompression. Studies of acute deterioration of CMI are scarce. The identification of preoperative radiological factors that predict acute deterioration in adult patients with CMI facilitates planning of early decompression and decreases CMI-related morbidity.Patients and methods: This is a retrospective study of all adult patients with CMI who were referred to Sahlgrenska University Hospital, Sweden and underwent occipitocervical decompression in the period 2006-2016. In total, 65 consecutive patients were included and data regarding the preoperative degree of tonsillar herniation and syrinx (size, length and degree of rostral extension) were registered. Acute deterioration and the need for urgent surgical decompression within 24 h of hospitalisation were noted.Results: Three patients presented with acute deterioration of symptoms (4.6%) and showed an increased length and size of syrinx and more rostral extension of syrinx as compared to non-acute patients with CMI.Conclusion: Our study highlights the incidence of acute deterioration of CMI and shows the importance of assessing preoperative size, length and rostral extension of CMI-associated syrinx as indicators of acute deterioration so that CMI patients can be assigned to early surgical decompression.

Quality of Life After Combined Endonasal Endoscopic Odontoidectomy and Posterior Suboccipital Decompression and Fusion

BACKGROUND

Basilar invagination can result from systemic diseases that can weaken structural integrity of the craniocervical junction. Definitive treatment often requires ventral decompression and posterior decompression and fusion. Endonasal odontoidectomy is a relatively new minimal access procedure; quality of life (QOL) after this procedure has not been reported.

METHODS

We reviewed a consecutive database of endonasal odontoidectomy cases and identified patients having posterior decompression and fusion. Two QOL questionnaires were administered postoperatively: Sino-Nasal Outcome Test and 36-Item Short Form Survey. Comparisons with other endonasal or Chiari procedures were performed.

RESULTS

The study comprised 14 patients; 79% had Chiari malformation in addition to basilar invagination. Mean follow-up was 17.2 months. Symptomatic improvement occurred in 78.6% after surgery. Average postoperative Sino-Nasal Outcome Test scores were 39.2 ± 17.93, with worst scores in areas related to fatigue and sleep patterns but not nasal function. 36-Item Short Form Survey scores were lower in areas of physical function and general health but better for emotional health and pain. Compared with patients undergoing Chiari malformation surgery without endonasal odontoid resection or fusion, patients undergoing odontoidectomy had higher QOL in areas of role emotional, emotional well-being, and pain but worse QOL in general health and role physical.

CONCLUSIONS

Patients undergoing posterior decompression and fusion with endonasal odontoidectomy do well after surgery with respect to nasal function and emotional health. Patients who also have severe basilar invagination associated with systemic diseases demonstrate reduced QOL after surgery in areas of physical function and sleep leading to fatigue, irritability, and concentration difficulty, likely related to their systemic disease.

Surgical History of Sleep Apnea in Pediatric Patients with Chiari Type 1 Malformation

Sleep apnea represents a relative indication for posterior fossa decompression in pediatric patients with Chiari malformation type 1. Duraplasty was associated with improvement of sleep apnea in 100% of patients and dural splitting with improvement in 50% of patients. Duraplasty and dural splitting were associated with a similar reduction in tonsillar herniation on radiographic imaging of 58% (37% excluding tonsillectomy) and 35%, respectively. Longitudinal follow-up studies of patients with either neurologic deficits or severe symptoms will further elucidate the natural history of Chiari malformation type 1 and more appropriately gauge the risk-benefit tradeoff of surgical intervention.

The association between sleep-disordered breathing and magnetic resonance imaging findings in a pediatric cohort with Chiari 1 malformation

BACKGROUND

The prevalence of sleep-disordered breathing (SDB) reported in the literature for Chiari malformation type 1 (CM1) is uniformly high (24% to 70%). In Canada, there is limited access to pediatric polysomnography (PSG). Therefore, the identification of clinical features would be invaluable for triaging these children.

OBJECTIVE

To identify demographic features, clinical symptoms/signs and radiological findings associated with SDB in a large pediatric cohort with CM1.

METHODS

A retrospective review was conducted on children with CM1 who underwent baseline PSG. Data were collected on patient demographics (age, sex, weight, height, body mass index), clinical symptoms (chart review and clinical questionnaires), diagnostic imaging of the brain and cervicothoracic spine, and medical history at the time of referral.

RESULTS

A total of 68 children were included in the review. The mean (± SD) age of the children at the time of PSG was 7.33 ± 4.01 years; 56% (n=38) were male. There was a 49% prevalence of SDB in this cohort based on the overall apnea-hypopnea index. Obstructive sleep apnea was the predominant type of SDB. Tonsillar herniation was significantly correlated with obstructive apnea-hypopnea index (r=0.24; P=0.036).

CONCLUSIONS

A direct relationship between the degree of cerebellar tonsillar herniation and obstructive sleep apnea was demonstrated. However, further prospective studies that include neurophysiological assessment are needed to further translate the central nervous system imaging findings to predict the presence of SDB.

Chiari 1 Malformation Presenting as Central Sleep Apnea during Pregnancy: A Case Report, Treatment Considerations, and Review of the Literature

Purpose: Chiari malformation (CM) type-1 frequently causes obstructive or central sleep-disordered breathing (SDB) in both adults and children, although SDB is relatively rare as a presenting manifestation in the absence of other neurological symptoms. The definitive treatment of symptomatic CM is surgical decompression. We report a case that is, to our knowledge, a novel manifestation of central sleep apnea (CSA) due to CM type-1 with severe exacerbation and initial clinical presentation during pregnancy.

Methods: Case report from tertiary care comprehensive sleep medicine center with literature review of SDB manifestations associated with CM type-1. PubMed search was conducted between January 1982 and October 2013.

Results: We report a 25-year-old woman with severe CSA initially presenting during her first pregnancy that eventually proved to be caused by CM type-1. The patient was successfully treated preoperatively by adaptive servoventilation (ASV), with effective resolution of SDB following surgical decompression, and without recurrence in a subsequent pregnancy. Our literature review found that 58% of CM patients with SDB had OSA alone, 28% had CSA alone, 8 (10%) had mixed OSA/CSA, and 6 (8%) had hypoventilation. Of CM patients presenting with SDB, 50% had OSA, 42% had CSA, 8% had mixed OSA/CSA, and 10.4% had hypoventilation. We speculate that CSA may develop in CM patients in whom brainstem compression results in excessive central chemoreflex sensitivity with consequent hypocapnic CSA.

Conclusion: Chiari malformation type-1 may present with a diversity of SDB manifestations, and timely recognition and surgical referral are necessary to prevent further neurological deficits. ASV therapy can effectively manage CSA caused by CM type-1, which may initially present during pregnancy.

The comparative morphometric study of the posterior cranial fossa : what is effective approaches to the treatment of Chiari malformation type 1?

Objective

The objective of this study was to investigate changes in the posterior cranial fossa in patients with symptomatic Chiari malformation type I (CMI) compared to a control group.

Methods

We retrospectively reviewed clinical and radiological data from 12 symptomatic patients with CMI and 24 healthy control subjects. The structures of the brain and skull base were investigated using magnetic resonance imaging.

Results

The length of the clivus had significantly decreased in the CMI group than in the control group (p=0.000). The angle between the clivus and the McRae line (p<0.024), as the angle between the supraocciput and the McRae line (p<0.021), and the angle between the tentorium and a line connecting the internal occipital protuberance to the opisthion (p<0.009) were significantly larger in the CMI group than in the control group. The mean vertical length of the cerebellar hemisphere (p<0.003) and the mean length of the coronal and sagittal superoinferior aspects of the cerebellum (p<0.05) were longer in the CMI group than in the control group, while the mean length of the axial anteroposterior aspect of the cerebellum (p<0.001) was significantly shorter in the CMI group relative to control subjects.

Conclusion

We elucidate the transformation of the posterior cranial fossa into the narrow funnel shape. The sufficient cephalocaudal extension of the craniectomy of the posterior cranial fossa has more decompression effect than other type extension of the craniectomy in CMI patients.

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.

Sudden onset of Chiari malformation Type I in previously asymptomatic patients

Chiari malformation Type I (CM-I) is usually suspected in patients with slowly progressing neurological symptoms. However, in some instances, especially if syringomyelia is associated, an abrupt clinical onset is reported and is accompanied by an acknowledged risk of potentially severe clinical signs or even sudden death. Little is known about such a critical course in CM-I/syringomyelia complex. The authors describe 3 challenging cases of the abrupt onset of CM-I/syringomyelia to reveal more information on the clinical presentation and pathogenetic mechanisms of this sudden and potentially severe clinical phenomenon: a 38-year-old man experienced acute respiratory failure requiring intubation following acute decompensation of hydrocephalus associated with Noonan syndrome, a 1-year-old boy had sudden hemiparesis and Horner syndrome after a minor head/neck injury, and a 2.5-year-old boy presented with quickly progressing tetraplegia and dyspnea after a mild flexion and extension neck injury a few hours before. All 3 patients showed a CM-I/syringomyelia complex at diagnosis, and all of them had a good neurological outcome after surgery despite the ominous clinical presentation.

Acute deterioration of a Chiari I malformation: an uncommon neurosurgical emergency

OBJECTIVES

Report and discuss acute neurological deterioration of Chiari I malformation (CMI), surgical treatment and timing, clinical outcome and literature review.

CASE REPORT

We report a recent case of a 15-year-old girl admitted for an acute neurological deterioration caused by an undiagnosed hindbrain herniation that required an urgent foramen magnum decompression and external ventricular drainage insertion. Moreover, we report and discuss the literature. To the authors' knowledge, this is only the third paediatric patient identified in this setting to be treated for an acute neurological deterioration due to a previous asymptomatic hindbrain herniation. The patient made an uncomplicated recovery and was discharged home on the seventh postoperative day and has remained well at review.

DISCUSSION

Acute deterioration of CMI in completely asymptomatic patients in absence of concomitant pathological findings is rarely reported in the literature, and exceptional in children.

CONCLUSIONS

CMI is typically treated electively, but as this case illustrates, it can present with rapidly deteriorating neurological signs. Symptoms usually respond well to surgical intervention with rapid improvement.

Posterior cranial fossa morphometry in symptomatic adult Chiari I malformation patients: comparative clinical and anatomical study

BACKGROUND AND OBJECTIVES

The cerebellar tonsillar herniation occurring in Chiari malformation Type I (CMI) mainly results from overcrowding of a normally developing hindbrain within a primary small posterior cranial fossa (PCF) due to an anomaly in the embryological development of the occipital bone. In the present study, the lengths of PCF parameters were studied in adult CMI patients.

PATIENTS AND METHODS

The authors retrospectively examined 15 adult patients with CMI. Multiple measurements were made on magnetic resonance images (MRIs). The results were compared with the findings in 25 controls and 30 dry skulls.

RESULTS

Length of the neural structures did not significantly differ between the CMI and the control groups. The average length of the basiocciput was significantly shorter in the CMI group as compared with the control group. The mean length of the supraocciput was significantly shorter and the average diameter of the foramen magnum was significantly longer in the CMI group when compared to the control group and dry skulls.

CONCLUSIONS

The morphometric data suggest that, in CMI, a hypoplastic occipital bone, possibly due to the paraxial mesodermal defect of the parachordal plate, causes overcrowding in PCF, which contains the normally developed neural structures.

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.

Isolated central sleep apnea in type I Chiari malformation: improvement after surgery

Sleep apnea is a rare but well-known clinical feature of disorders of the craniocervical junction. It may be obstructive or central in nature, and rarely presents without other neurological symptoms. We report the cases of two children, presenting with isolated central sleep apnea leading to a diagnosis of type I Chiari malformation. Surgical treatment resulted in a dramatic improvement in respiratory parameters during sleep, both clinically and on polysomnography. We discuss this uncommon presentation of type I Chiari malformation and suggest that it be considered in the differential diagnosis of central sleep apnea in children, as posterior fossa decompression may lead to significant clinical improvement.

Improvement of obstructive sleep apneas caused by hydrocephalus associated with Chiari malformation Type II following surgery

Chiari malformation (CM) is the downward herniation of the caudal part of the cerebellum and/or medulla oblongata into the spinal canal. It can alter several neurological functions, including respiratory control and upper airway motility, and can be the cause of sleep-disordered breathing (SDB). The authors describe a 6-year-old boy affected by CM Type II associated with myelomeningocele who showed symptoms indicative of severe airway obstruction during sleep. Polysomnography revealed severe obstructive sleep apnea syndrome (OSAS). Magnetic resonance imaging demonstrated herniation of the cerebellar tonsils and diffuse ventricular dilation with a large pseudocystic formation in the third ventricle. Surgical marsupialization of the cystic wall was performed, associated with ventriculocystostomy and endoscopic replacement of the ventricular catheter. Polysomnography repeated 2 months after surgery revealed a striking improvement in the sleep-related respiratory pattern. The pathogenesis of OSAS was probably referable to a combination of CM and elevated intracranial pressure. However, the striking improvement of symptoms after ventriculoatrial shunt placement suggested that hydrocephalus plays a major role in this condition. Assessment and effective treatment of SDB is crucial in the care of patients with CM.

Hypoventilation syndromes

A wide variety of mechanisms can lead to the hypoventilation associated with various medical disorders, including derangements in central ventilatory control, mechanical impediments to breathing, and abnormalities in gas exchange leading to increased dead space ventilation. The pathogenesis of hypercapnia in obesity hypoventilation syndrome remains somewhat obscure, although in many patients comorbid obstructive sleep apnea appears to play an important role. Hypoventilation in neurologic or neuromuscular disorders is primarily explained by weakness of respiratory muscles, although some central nervous system diseases may affect control of breathing. In other chest wall disorders, obstructive airways disease, and cystic fibrosis, much of the pathogenesis is explained by mechanical impediments to breathing, but an element of increased dead space ventilation also often occurs. Central alveolar hypoventilation syndrome involves a genetically determined defect in central respiratory control. Treatment in all of these disorders involves coordinated management of the primary disorder (when possible) and, increasingly, the use of noninvasive positive pressure ventilation.

Chiari malformation Type I in children younger than age 6 years: presentation and surgical outcome

OBJECT

The authors conducted a study to evaluate the unique presenting signs and symptoms of Chiari malformation Type I (CM-I) in children younger than 6 years of age and highlight the benefits of early surgical treatment in this patient population.

METHODS

The authors reviewed the medical records of patients who presented to the neurosurgery department before their 6th birthday and subsequently underwent surgery for CM-I. They identified 39 patients who had been evaluated between 1984 and 2007 and examined the medical records for presentation, surgical intervention, and outcome.

RESULTS

Children aged 0-2 years commonly presented with oropharyngeal dysfunction (77.8%). Children aged 3-5 years more frequently presented with syringomyelia (85.7%), scoliosis (38.1%), and/or headache (57.1%). All patients underwent posterior fossa craniectomy. Additionally, in many patients cervical laminectomy and/or duraplasty was performed. A few patients required transoral decompression and occipitocervical fusion. In most cases, surgery led to resolution or dramatic improvement of initial symptoms.

CONCLUSIONS

Early recognition and surgical treatment of CM-I in young children leads to good outcomes in the majority of patients. Additional therapies for oropharyngeal dysfunction, syringomyelia, and scoliosis can frequently be avoided.

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.

Chiari malformation and sleep related breathing disorders

OBJECTIVE

To estimate the frequency, mechanisms and predictive factors of sleep apnoea syndrome (SAS) in a large group of children and adults with type I (CMI) and II (CMII) Chiari malformation (CM).

BACKGROUND

The anatomical and functional integrity of both respiratory circuits and lower cranial nerves controlling the upper airway is necessary for breathing control during sleep. These latter structures may be altered in CM, and a few investigations have reported CM related sleep disordered breathing.

METHODS

Forty-six consecutive unrelated patients with CM (40 CMI, six CMII), of which 20 were children (eight males) and 26 were adults (12 males), underwent physical, neurological and oto-rhino-laryngoscopic examination, MRI and polysomnography.

RESULTS

SAS was present in 31 (67.4%) of the patients with CM (70% of CMI, 50% of CMII, including mainly children). Sixty per cent of children with CM exhibited SAS, including 35% with obstructive (OSAS) and 25% with central (CSAS) sleep apnoea syndrome. SAS was observed in 73% of CM adults (57.7% OSAS, 15.4% CSAS). Severe SAS was found in 23% of CM adults. Multiple regression analysis revealed that age, type II Chiari and vocal cord paralysis predicted the central apnoea index.

CONCLUSION

SAS is highly prevalent in all age groups of patients suffering from CM. CSAS, a rare condition in the general population, was common among the patients with CM in our study. Sleep disordered breathing associated with CM may explain the high frequency of respiratory failures observed during curative surgery of CM. Our results suggest that SAS should be systematically screened for in patients with CM, especially before surgery.

Urgent surgical intervention in pediatric patients with Chiari malformation type I. Report of two cases

Patients with Chiari malformation Type I (CM-I) most commonly present with chronic symptoms. A search of the current medical literature revealed scant information regarding acute presentations of CM-I in either pediatric or adult patients. The authors report on two children who presented with rapidly worsening neurological symptoms attributable to a previously undiagnosed CM-I. One patient became profoundly hypopneic with dysphagia and right hemiparesis over a less than 48-hour period. The second patient presented with a few days of worsening right hemiparesis, gait disturbance, and anisocoria. In addition to a CM-I, magnetic resonance imaging in the second patient revealed a holocord syrinx. Following urgent posterior fossa decompression, both patients rapidly improved in the 24 hours immediately following surgery and continued to improve in the subsequent weeks. Few reports detail acute symptoms due to CM-I and those that do exist almost exclusively involve adult patients. Although seemingly rare, the clinician should consider CM-I in the differential diagnosis in pediatric patients presenting with acute brainstem or long tract signs.