Association of methylenetetrahydrofolate reductase genetic polymorphisms with atlantoaxial dislocation

Multidetector Computed Tomography and Magnetic Resonance Imaging Evaluation of Craniovertebral junction Abnormalities

BACKGROUND

Craniovertebral junction (CVJ) abnormalities constitute an important group of treatable neurological disorders with diagnostic dilemma. Their precise diagnosis, identification of probable etiology, and pretreatment evaluation significantly affects prognosis and quality of life of patients.

AIMS

The study was to classify various craniovertebral junction disorders according to their etiology and to define the importance of precise diagnosis for pretreatment evaluation with multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI).

MATERIALS AND METHODS

This is a prospective observational study of 62 patients referred to our department between October 2012 and September 2014. All patients suspected to have a craniovertebral junction disorder were included in the study, from all age groups and both genders. Detailed clinical history was taken. Radiographs of cervical spine were collected if available. All patients were subjected to MDCT and/or MRI.

RESULTS

In our study of 62 patients; 39 were males and 23 were females, with male to female ratio of 1.6:1. Most common age group was 2(nd) -3(rd) decade (19 patients, 30.64%). Developmental anomalies (33 patients, 53.22%) were the most common etiology group followed by traumatic (10 patients, 16.12%), degenerative (eight patients, 12.90%), infective (four patients, 6.45%), inflammatory and neoplastic (three patients each, 4.8%), and no cause found in one patient.

CONCLUSIONS

CVJ abnormalities constitute an important group of treatable neurological disorders, especially in certain ethnic groups and are approached with much caution by clinicians. Thus, it is essential that radiologists should be able to make a precise diagnosis of craniovertebral junction abnormalities, classify them into etiological group, and rule out important mimickers on MDCT and/or MRI, as this information ultimately helps determine the management of such abnormalities, prognosis, and quality of life of patients.

Pediatric bony craniovertebral junction abnormalities: Institutional experience of 10 years

Objective:

To study the clinical features and treatment outcome of pediatric patients with bony craniovertebral abnormalities.

Materials and Methods:

The authors studied 189 consecutive cases of pediatric bony craniovertebral junction abnormalities operated between 2001 and March, 2010.

Results:

The pathologies were developmental (n = 162), traumatic (n = 18) and tuberculous (n = 9). Surgical procedures included transoral decompression (n = 118), occipitocervical fusion (OCF, n = 139), C 1 -C 2 fusion (n = 45), and posterior fossa decompression (n = 5). Methods for OCF included contoured stainless steel rods (n = 86), titanium lateral mass screws and plates (n = 47) and steel wires (n = 6). Constructs of all patients of posterior fixation with contoured rods and wires or lateral mass screw and rod who could be followed up were either stable/fused or were fused and stable. No implant failure was noticed among these two surgical procedures. However, 6 patients with C 1-C 2 fusion had broken wires on follow-up requiring repeat posterior fixation. Good neurological outcome was observed even in poor-grade patients. No significant effect on the curvature or growth of the spine was observed at follow-up.

Conclusions:

Pediatric craniovertebral junction anomalies can be managed successfully with good outcomes using a low cost contoured rod and wires.

A 6-year experience of 100 cases of pediatric bony craniovertebral junction abnormalities: treatment and outcomes

The authors studied 100 consecutive cases of pediatric bony craniovertebral junction abnormalities operated between 2001 and 2006. The pathologies were developmental (n = 86), traumatic (n = 10) and tuberculous (n = 4). Surgical procedures included transoral decompression (n = 59), occipitocervical fusion (OCF, n = 69), C(1)-C(2) fusion (n = 22), occiput-C(2) wiring (n = 5), and posterior fossa decompression (n = 5). Implants for OCF included contoured stainless steel rods (n = 47), titanium lateral mass screws and plates (n = 16) and steel wires (n = 5). Adequate bone fusion was observed in all patients with OCF at a mean follow-up of 16.5 months, irrespective of the type of implant used for posterior fixation. Good neurological outcome was observed even in poor-grade patients. No significant effect on the curvature or growth of the spine was observed at follow-up.

Os odontoideum with "free-floating" atlantal arch causing C1-2 anterolisthesis and retrolisthesis with cervicomedullary compression

BACKGROUND

Os odontoideum (OO) with C1-2 anterolisthesis and retrolisthesis may cause cervicomedullary injury both from anterior and posterior aspects. We analyzed fourteen such patients for biomechanical issues, radiological features and management of OO with free-floating atlantal arch and review pertinent literature.

MATERIALS AND METHODS

Fourteen patients having nonsyndromic, reducible atlantoaxial dislocation (AAD) with orthotopic OO were analyzed. During neck flexion, their C1 anterior arch-os complex displaced anteriorly relative to remnant odontoid-C2 body. The posteriorly directed hypoplastic remnant odontoid sliding below the atlas and forward translation of the C1 posterior arch caused concomitant cervicomedullary compression. During neck extension, there was retrolisthesis of the "free-floating" C1 arch-os complex into spinal canal. Spinal stenosis and lateral C1-2 facet dislocation; Klippel-Feil anomaly; and posterior circulation infarcts were also present in one patient each, respectively. Posterior C1-2 (n=10) or occipitocervical fusion (n=3) was performed in neutral position to stabilize atlantoaxial movements.

RESULTS

Follow-up (mean, 3.9 years) assessment revealed improvement in spasticity and weakness in 13 patients. One patient had neurological deterioration following C1-2 posterior sublaminar fusion, requiring its conversion to occipitocervical contoured rod fusion. One patient with posterior circulation stroke died prior to any operative intervention. Follow-up lateral view radiographs showed a bony union or a stable construct in these 13 patients.

CONCLUSIONS

OO with free-floating atlantal arch may precipitate cord injury both during neck flexion and extension. This condition may be overlooked unless lateral radiographs of craniovertebral junction are undertaken in neck extension, along with the usual ones in neutral and flexed positions. Etiological factors include C1 ring-OO unrestrained movements above the hypoplastic odontoid; upward pull on OO by alar and apical ligaments; lax C1-2 facet joint ligaments; and congenital presence of horizontal facet joint surfaces that facilitates C1-2 translation.