Timing to surgery of Chiari malformation type 1 affects complication types: An analysis of 13,812 patients

Concurrent Presence of Thoracolumbar Scoliosis and Chiari Malformation: Is Operative Risk Magnified?

STUDY DESIGN

Retrospective review of Kids' Inpatient Database (KID).

PURPOSE

Identify the risks and complications associated with surgery in adolescents diagnosed with Chiari and scoliosis.

OVERVIEW OF LITERATURE

Scoliosis is frequently associated with Chiari malformation (CM). More specifically, reports have been made about this association with CM type I in the absence of syrinx status.

METHODS

The KID was used to identify all pediatric inpatients with CM and scoliosis. The patients were stratified into three groups: those with concomitant CM and scoliosis (CMS group), those with only CM (CM group), and those with only scoliosis (Sc group). Multivariate logistic regressions were used to assess association between surgical characteristics and diagnosis with complication rate.

RESULTS

A total of 90,707 spine patients were identified (61.8% Sc, 37% CM, 1.2% CMS). Sc patients were older, had a higher invasiveness score, and higher Charlson comorbidity index (all p<0.001). CMS patients had significantly higher rates of surgical decompression (36.7%). Sc patients had significantly higher rates of fusions (35.3%) and osteotomies (1.2%, all p<0.001). Controlling for age and invasiveness, postoperative complications were significantly associated with spine fusion surgery for Sc patients (odds ratio [OR], 1.8; p<0.05). Specifically, posterior spinal fusion in the thoracolumbar region had a greater risk of complications (OR, 4.9) than an anterior approach (OR, 3.6; all p<0.001). CM patients had a significant risk of complications when an osteotomy was performed as part of their surgery (OR, 2.9) and if a spinal fusion was concurrently performed (OR, 1.8; all p<0.05). Patients in the CMS cohort were significantly likely to develop postoperative complications if they underwent a spinal fusion from both anterior (OR, 2.5) and posterior approach (OR, 2.7; all p<0.001).

CONCLUSIONS

Having concurrent scoliosis and CM increases operative risk for fusion surgeries despite approach. Being independently inflicted with scoliosis or Chiari leads to increased complication rate when paired with thoracolumbar fusion and osteotomies; respectively.

Respiratory arrest after posterior fossa decompression in patients with Chiari malformations: An overview

Background

Chiari malformation type 1 (CM1) is a structural abnormality in the skull and cerebellum, causing cerebellar tonsils to shift downward. Decompression of the posterior fossa is a common surgical method to relieve symptoms and prevent neurological deterioration. After posterior fossa decompression (PFD), individuals with CM1 were more likely to have respiratory arrest. Here, we present, for the first time, a comprehensive overview of the potential risk factors and causes of respiratory arrest following PFD.

Methods

A review of the literature highlighting the risk factors for postoperative respiratory arrest in CM1 patients was conducted in the databases of PubMed, Medline, and Google Scholar.

Results

Patients with syringomyelia and CM1 are at increased risk for respiratory arrest due to a number of factors, including impaired respiratory mechanics, central respiratory center dysfunction from edema or ischemia, intraoperative brain stem ischemia, and delayed gastric emptying from autonomic dysfunction. Occipitalization of the first cervical vertebra, basilar impression, and fusion of C2-C3 are all risk factors for respiratory arrest.

Conclusion

Implications for CM1 patient care and prospects for further investigation of postoperative respiratory arrest's causes and risk factors were discussed.

Prevalence of Chiari malformation type 1 is increased in pseudohypoparathyroidism type 1A and associated with aberrant bone development

BACKGROUND

Albright hereditary osteodystrophy (AHO) is caused by heterozygous inactivating mutations in GNAS. Patients with maternally-inherited mutations develop pseudohypoparathyroidism type 1A (PHP1A) with multi-hormone resistance and aberrant craniofacial and skeletal development among other abnormalities. Chiari malformation type 1 (CM1), a condition in which brain tissue extends into the spinal canal when the skull is too small, has been reported in isolated cases of PHP1A. It has been hypothesized to be associated with growth hormone (GH) deficiency. Given the adverse clinical sequelae that can occur if CM1 goes unrecognized, we investigated the previously undetermined prevalence of CM1, as well as any potential correlations with GH status, given the known increased prevalence of GH deficiency in PHP1A. We also investigated these metrics for low lying cerebellar tonsils (LLCT), defined as tonsillar descent less than 5 mm below the foramen magnum. In addition, we investigated possible correlations of CM1/LLCT with advanced hand/wrist bone ages and craniofacial abnormalities known to occur in PHP1A to determine whether premature chondrocyte differentiation and/or aberrant craniofacial development could be potential etiologies of CM1/LLCT through both human studies and investigations of our AHO mouse model.

METHODS

We examined patients with PHP1A in our clinic and noticed CM1 more frequently than expected. Therefore, we set out to determine the true prevalence of CM1 and LLCT in a cohort of 54 mutation-confirmed PHP1A participants who had clinically-indicated brain imaging. We examined potential correlations with GH status, clinical features, biological sex, genotype, and hand/wrist bone age determinations. In addition, we investigated the craniofacial development in our mouse model of AHO (Gnas E1+/-m) by histologic analyses, dynamic histomorphometry, and micro-computerized tomographic imaging (MCT) in order to determine potential etiologies of CM1/LLCT in PHP1A.

RESULTS

In our cohort of PHP1A, the prevalence of CM1 is 10.8%, which is at least 10-fold higher than in the general population. If LLCT is included, the prevalence increases to 21.7%. We found no correlation with GH status, biological sex, genotype, or hand/wrist bone age. Through investigations of our Gnas E1+/-m mice, the correlate to PHP1A, we identified a smaller cranial vault and increased cranial dome angle with evidence of hyperostosis due to increased osteogenesis. We also demonstrated that there was premature closure of the spheno-occipital synchondrosis (SOS), a cartilaginous structure essential to the development of the cranial base. These findings lead to craniofacial abnormalities and could contribute to CM1 and LLCT development in PHP1A.

CONCLUSION

The prevalence of CM1 is at least 10-fold higher in PHP1A compared to the general population and 20-fold higher when including LLCT. This is independent of the GH deficiency that is found in approximately two-thirds of patients with PHP1A. In light of potential serious consequences of CM1, clinicians should have a low threshold for brain imaging. Investigations of our AHO mouse model revealed aberrant cranial formation including a smaller cranium, increased cranial dome angle, hyperostosis, and premature SOS closure rates, providing a potential etiology for the increased prevalence of CM1 and LLCT in PHP1A.

Above-The-Hairline Suboccipital Transverse Approach for the Treatment of Chiari I Malformation

BACKGROUND

Chiari I malformation is a common pediatric neurosurgical disorder with an established treatment paradigm. Posterior fossa decompression and duraplasty (PFDD) is associated with symptom improvement but it carries postoperative risk, particularly cerebrospinal fluid (CSF) leak and wound complications. In addition, the cosmetic outcomes of PFDD have been overlooked in the literature.

OBJECTIVE

To describe a novel approach for PFDD in which the transverse surgical incision is completely hidden above the hairline and to report early outcomes in a prospective patient cohort.

METHODS

Clinical and cosmetic outcomes were recorded for 15 consecutive pediatric patients who underwent PFDD for Chiari I malformation via the above-the-hairline transverse suboccipital approach.

RESULTS

The median clinical follow-up time was 6 months (range 1-12 months), and the majority of patients experienced significant improvement of their preoperative symptoms. Three patients (20%) experienced complications associated with surgery, which included injury to the greater occipital nerve, CSF hypotension and subfascial pseudomeningocele, and superficial wound dehiscence that resolved spontaneously with oral antibiotics. Zero patients (0%) returned to the operating room for persistent CSF leak, deep wound infection, or revision decompression. An excellent cosmetic outcome was achieved in 12 patients (80%). No patient had a poor cosmetic outcome.

CONCLUSION

The above-the-hairline transverse suboccipital approach for PFDD in patients with Chiari I malformation offers favorable cosmetic outcomes and fascial closure while permitting adequate decompression.

Progressive Flaccid Paraplegia in a Toddler due to Chiari Type I Malformation Complicated with Hydrocephalus and Syringomyelia. A Case Report

Chiari malformation is a clinico-radiological entity defined by herniation of rhombencephalic structures through the foramen magnum. The most common type, Chiari I, involves herniation of the cerebellar tonsils specifically. We present the case of a 2-year-old with three weeks of progressive bilateral leg weakness, absent reflexes, and the inability to walk. The patient was found to have Chiari I with hydrocephalus and syringomyelia. This is the youngest patient reported in the literature presenting with a clinical picture of spinal shock. Early recognition of this entity allows for proper treatment and improved outcomes.

Case Report: Downbeat Nystagmus Due to Epidural Puncture during Labor with Undiagnosed Arnold Chiari Malformation

SIGNIFICANCE

Epidural anesthesia is a safe procedure used in pregnant patients during labor. However, caution should be exercised in those patients that have concurrent Arnold Chiari malformation.

PURPOSE

To report a rare and atypical presentation of downbeat nystagmus, in a pregnant patient with Arnold Chiari malformation type 1 (ACM1), secondary to accidental dural puncture.

CASE REPORT

A 31-year-old African American female presented with a chief complaint of decreased vision and oscillopsia that occurred after giving birth, six months earlier. Her medical history prior to presentation was unremarkable. Her delivery was typical; however, the patient did receive epidural anesthesia which resulted in a dural puncture. The patient noted her symptoms a few days after delivery. Upon examination, persistent down beat nystagmus was noted in both eyes. Magnetic resonance imaging revealed a 2.5 cm inferior displacement of the cerebellar tonsils below the foramen magnum consistent with ACM1. The patient was referred to neurosurgery for posterior fossa decompression. However, surgery was deferred until appropriate weight reduction could be achieved. Follow-up examination six months later revealed no change in her clinical findings.

CONCLUSIONS

This case report highlights an atypical presentation of downbeat nystagmus secondary to an accidental dural puncture in a pregnant patient with undiagnosed ACM1. Clinicians should consider the importance of considering ocular complications that can occur in pregnant patients with ACM1. Questioning of women who have recently given birth about epidural anesthesia should be considered with an acute presentation of downbeat-nystagmus.