Neurosurgical implications of achondroplasia

King, James; Vachhrajani, Shobhan; Drake, James M.; Rutka, James T.

doi:10.3171/2009.3.peds08344

Cited by 85 publications

(75 citation statements)

References 39 publications

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“…10 CMD has shown to improve the central apneas and the degree of oxygen desaturation. 7 The most common surgical complication of CMD is CSF leak and infection.…”

Section: Discussionmentioning

confidence: 99%

A Three-Month-Old Achondroplastic Baby with both Obstructive Apneas and Central Apneas

DelRosso

Gonzalez‐Toledo²,

Hoque³

2013

Journal of Clinical Sleep Medicine

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A 3-month-old infant girl with achondroplasia presented with a 2-month history of snoring without breathing pauses, nasal fl aring, chest retraction, or cyanosis. The baby was born at 38 weeks gestation to a 33-year-old mother via elective cesarean section. Apgar score was 9. The father is achondroplastic. At 6 months gestation, fetal ultrasound was consistent with achondroplasia; prenatal and perinatal history was otherwise unremarkable.Physical exam revealed an alert playful baby with macrocephaly, head circumference of 44 cm (50% percentile achondroplasia chart) 1 ; mid-face hypoplasia; and large anterior and posterior fontanelles. Upper airway was Mallampati IV with 2+ tonsillar enlargement. No excessive palatal arching was noted. Neurologic exam revealed mild hypotonia, lumbar kyphosis, and normal deep tendon refl exes throughout. The remainder of the exam was normal.Computerized tomography (CT) of the head with 3-dimensional reconstruction showed widening of the metopic, coronal, and sagittal sutures, with patent anterior and posterior fontanelles. Mild foramen magnum narrowing was noted without evidence of cervicomedullary junction stenosis (Figure 1). Diagnostic polysomnogram (PSG) revealed a total sleep time (TST) apnea-hypopnea index (AHI) of 4, with 15 obstructive apneas and 15 central apneas; NREM AHI of 1.8; and REM AHI of 11.6. The apneas were not associated with bradycardia; the lowest heart rate for the night was 95 bpm. The apneas were brief and met American Academy of Sleep Medicine Scoring Manual criteria for duration with 2 missed breaths. The central apneas were associated with 3% oxygen desaturation. The minimum oxygen saturation was 91%. There was no evidence of hypoventilation. The end-tidal CO 2 remained below 50 mm Hg for the entirety of the night, with an average of 35 mm Hg.

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“…10 CMD has shown to improve the central apneas and the degree of oxygen desaturation. 7 The most common surgical complication of CMD is CSF leak and infection.…”

Section: Discussionmentioning

confidence: 99%

A Three-Month-Old Achondroplastic Baby with both Obstructive Apneas and Central Apneas

DelRosso

Gonzalez‐Toledo²,

Hoque³

2013

Journal of Clinical Sleep Medicine

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“…2 The need for cervicomedullary decompression in magnetic resonance imaging (MRI) era is 13% to 15% and more than 50% of the affected infants are below 24 months of age. 1,2 The clinical indications for neural decompression of the cervicomedullary junction have been brainstem myelopathy, central sleep apnea, and T2 changes on MRI of the cervicomedullary junction.…”

Section: Commentaries 1035mentioning

confidence: 99%

“…1 While the locus of the ERD is in neural areas associated with planning for the typical reference group, the locus of the ERD is in neuronal groups involved in processing sensory information for the group with CP. Kurz et al propose that the increased sensory processing is a compensation for a faulty internal model of the musculoskeletal system, which can be compromised by somatosensory deficits.…”

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confidence: 99%

“…

This commentary is on the original article by Kurz et al on pages 1072-1077 of this issue.Kurz et al 1 analyzed patterns of neural oscillatory activity in the sensorimotor cortices to investigate motor planning in children with cerebral palsy (CP). Specifically, they studied event-related desynchronization (ERD) of oscillations in the beta frequency band, which are associated with movement preparation.

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confidence: 99%

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Neurophysiological evidence for motor planning limitations in children with cerebral palsy

Valvano

2014

Develop Med Child Neuro

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This commentary is on the original article by Kurz et al. on pages 1072-1077 of this issue.Kurz et al. 1 analyzed patterns of neural oscillatory activity in the sensorimotor cortices to investigate motor planning in children with cerebral palsy (CP). Specifically, they studied event-related desynchronization (ERD) of oscillations in the beta frequency band, which are associated with movement preparation. The experimental task in this study involved repeated, short-range movements into knee extension while focusing on a fixed target. Motor planning was defined in terms of selecting the proper muscular coordination to initially extend the knee. Motor planning impairments in the group with CP were inferred from statistically significant differences in the magnitude of the desynchronization, as well as variations in the locus of ERD compared to a typical reference group. The authors suggest that aberrations in neural oscillations in the preparation phase lead to aberrations in oscillatory patterns during movement execution. It is important to note the individual performance of participants with CP reported in the supplementary data.These electrophysiological findings corroborate mounting evidence in the behavioral domain for global motor planning impairments that significantly contribute to activity limitations in children with CP.2-4 Although both symmetrical and unilateral spastic CP are implicated, most research on motor planning has involved the latter. Research paradigms that involve discrete tasks such as reach to grasp or lift to grasp are commonly used to study motor planning. These discrete tasks explicate anticipatory planning functions because they predict the end of the upcoming action when preparing the movement toward an object. The requirements of the discrete knee extension task used by Kurz et al. are comparable to the discrete upper extremity tasks. Therefore, performance of the knee extension task should reflect these anticipatory planning mechanisms.In fact, ERD patterns in the pre-activation phase did reveal shortcomings in anticipatory planning in the group with CP.

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“…10,17,21 The most serious neurological complication in patients with achondroplasia is cervicomedullary junction (CMJ) compression caused by a tight deformed foramen magnum. 10,13 Compression at the foramen magnum can result in cervical myelopathy manifested as clonus and hyperreflexia, hypotonia, sleep apnea, and even sudden death. 2,3,8,10,17 Due to the potentially lethal complications associated with symptomatic disease, neurosurgical decompression has been used to widen the foramen magnum and relieve the pressure on the emerging cervical cord.…”

mentioning

confidence: 99%

Dynamic cervicomedullary cord compression and alterations in cerebrospinal fluid dynamics in children with achondroplasia: review of an 11-year surgical case series

Mukherjee

Pressman

Krakow

et al. 2014

PED

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Object Achondroplasia may be associated with compression at the cervicomedullary junction. Determining which patients are at greatest risk for neurological complications of cervicomedullary compression can be difficult. In the current study the authors reviewed their records to determine the incidence and clinical significance of dynamic cervicomedullary stenosis and obstruction of CSF flow along with surgical outcomes following posterior fossa decompression. Methods The authors reviewed 34 consecutive cases involving symptomatic children with achondroplasia undergoing cervicomedullary decompression performed by a single surgeon over 11 years. Of these patients, 29 had undergone preoperative dynamic MRI of the cervicomedullary junction with cine (cinema) CSF flow studies; 13 of these patients underwent postoperative dynamic MRI studies. Clinical outcomes included changes in polysomnography, head circumference percentile, and fontanel characteristics. Radiographic outcomes included changes in dynamic spinal cord diameter, improvement in CSF flow at the foramen magnum, and change in the Evans ratio. Results Patients were predominantly female, with a mean age at presentation of 6.6 years and mean follow-up of 3.7 years (range 1–10 years). All patients had moderate to excellent improvement in postoperative polysomnography, slight decrease in average head circumference percentile (from 46.9th percentile to 45.7th percentile), and no subjective worsening of fontanel characteristics. The Evans ratio decreased by 2%, spinal cord diameter increased an average of 3.1 mm, 5.2 mm, and 0.2 mm in the neutral, flexed, and extended positions, respectively, and CSF flow improved qualitatively in all 3 positions. There were no postoperative infections, CSF leaks, or other major complications. None of the patients undergoing initial foramen magnum decompression performed at our medical center required reoperation. Conclusions Patients with achondroplasia and symptomatic cervicomedullary compression have increased risk of dynamic stenosis at the foramen magnum evident upon dynamic cine MRI. Operative decompression may be offered with low risk of complications or need for reoperation.

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Neurosurgical implications of achondroplasia

Cited by 85 publications

References 39 publications

A Three-Month-Old Achondroplastic Baby with both Obstructive Apneas and Central Apneas

A Three-Month-Old Achondroplastic Baby with both Obstructive Apneas and Central Apneas

Neurophysiological evidence for motor planning limitations in children with cerebral palsy

Dynamic cervicomedullary cord compression and alterations in cerebrospinal fluid dynamics in children with achondroplasia: review of an 11-year surgical case series

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