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Proatlas segmentation anomalies: Surgical management of five cases and review of the literature.

Muthukumar N - J Pediatr Neurosci (2016 Jan-Mar)

Bottom Line: CT of the cranioveretebral junction was the key to the diagnosis of this anomaly.All patients improved during follow up.Proatlas segmentation defects are rare anomalies of the craniovertebral junction.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, Madurai Medical College, Madurai, Tamil Nadu, India.

ABSTRACT

Objective: Proatlas segementation anomalies are due to defective re-segmentation of the proatlas sclerotome. These anomalies of the craniovertebral junction are rare and have multiple presentations. The aim of this study is to report this author's personal experience in managing five of these patients with different radiological findings necessitating different surgical strategies and to provide a brief review of the relevant literature.

Materials and methods: Five patients, all in the second decade of life were treated between 2010 and 2013. There were three males and two females. All the patients presented with spastic quadriparesis and/or cerebellar signs. Patients underwent plain radiographs, MRI and CT of the craniovertebral junction. CT of the cranioveretebral junction was the key to the diagnosis of this anomaly. Postoperatively, patients were assessed with plain radiographs and CT in all patients and MRI in one.

Results: Two patients underwent craniovertebral realignment with occipitocervical fixation, two patients underwent C1-C2 fixation using Goel-Harms technique and one patient underwent craniovertebral realignment with C1-C2 fixation using spacers in the atlanatoaxial joint and foramen magnum decompression. All patients improved during follow up.

Conclusions: Proatlas segmentation defects are rare anomalies of the craniovertebral junction. Routine use of thin section CT of the craniovertebral junction and an awareness of this entity and its multivarious presentations are necessary for clinicians dealing with abnormalities of the craniovertebral junction.

No MeSH data available.


Related in: MedlinePlus

(a) Sagittal T1-weighted (b) sagittal T2-weighted magnetic resonance imaging showing severe platybasia, basioccipital dysgenesis, ventral compression at the cervicomedullary junction, tonsillar ectopia up to C2 and cervical syrinx (c) preoperative sagittal computed tomography of the craniovertebral junction showing severe platybasia with basioccipital dysgenesis (white arrow head), the anterior arch of atlas (single white arrow) that is immediately subjacent to the horizontally oriented clivus and the “exuberant” apical segment of the dens (double white arrows)
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Figure 9: (a) Sagittal T1-weighted (b) sagittal T2-weighted magnetic resonance imaging showing severe platybasia, basioccipital dysgenesis, ventral compression at the cervicomedullary junction, tonsillar ectopia up to C2 and cervical syrinx (c) preoperative sagittal computed tomography of the craniovertebral junction showing severe platybasia with basioccipital dysgenesis (white arrow head), the anterior arch of atlas (single white arrow) that is immediately subjacent to the horizontally oriented clivus and the “exuberant” apical segment of the dens (double white arrows)

Mentions: A 23-year-old female presented to us with progressive difficulty in walking of 1-year duration. Examination revealed features of cervical myelopathy along with cerebellar signs. There was no evidence of lower cranial nerve palsies. MRI revealed features of platybasia with a horizontally oriented clivus, ventral brainstem compression at the cervicomedullary junction with tonsillar ecotpia extending up to C2, and a cervical syrinx [Figure 9a and b]. CT of the cervical spine showed platybasia with shortened basiocciput, anterior arch of atlas located immediately subjacent to the clivus, and an “exuberant” looking apical dental segment which was causing kinking of the cervicomedullary junction [Figure 9c]. The patient was placed under traction intraoperatively, and the C2 ganglion was sectioned bilaterally exposing the atlanto-axial joints which were then curetted and 4 mms titanium spacers were inserted into both the joints followed by placement of C1 lateral mass and C2 pars screws. This was followed by bony foramen magnum decompression without duraplasty to address the Chiari malformation. Postoperatively, the patient showed significant improvement in her weakness and cerebellar signs. Postoperative CT and MRI obtained 1 month later showed craniovertebral re-alignment with decompression of the cervicomedullary junction, resolution of syrinx, and tonsillar ascent [Figures 10–12].


Proatlas segmentation anomalies: Surgical management of five cases and review of the literature.

Muthukumar N - J Pediatr Neurosci (2016 Jan-Mar)

(a) Sagittal T1-weighted (b) sagittal T2-weighted magnetic resonance imaging showing severe platybasia, basioccipital dysgenesis, ventral compression at the cervicomedullary junction, tonsillar ectopia up to C2 and cervical syrinx (c) preoperative sagittal computed tomography of the craniovertebral junction showing severe platybasia with basioccipital dysgenesis (white arrow head), the anterior arch of atlas (single white arrow) that is immediately subjacent to the horizontally oriented clivus and the “exuberant” apical segment of the dens (double white arrows)
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4862281&req=5

Figure 9: (a) Sagittal T1-weighted (b) sagittal T2-weighted magnetic resonance imaging showing severe platybasia, basioccipital dysgenesis, ventral compression at the cervicomedullary junction, tonsillar ectopia up to C2 and cervical syrinx (c) preoperative sagittal computed tomography of the craniovertebral junction showing severe platybasia with basioccipital dysgenesis (white arrow head), the anterior arch of atlas (single white arrow) that is immediately subjacent to the horizontally oriented clivus and the “exuberant” apical segment of the dens (double white arrows)
Mentions: A 23-year-old female presented to us with progressive difficulty in walking of 1-year duration. Examination revealed features of cervical myelopathy along with cerebellar signs. There was no evidence of lower cranial nerve palsies. MRI revealed features of platybasia with a horizontally oriented clivus, ventral brainstem compression at the cervicomedullary junction with tonsillar ecotpia extending up to C2, and a cervical syrinx [Figure 9a and b]. CT of the cervical spine showed platybasia with shortened basiocciput, anterior arch of atlas located immediately subjacent to the clivus, and an “exuberant” looking apical dental segment which was causing kinking of the cervicomedullary junction [Figure 9c]. The patient was placed under traction intraoperatively, and the C2 ganglion was sectioned bilaterally exposing the atlanto-axial joints which were then curetted and 4 mms titanium spacers were inserted into both the joints followed by placement of C1 lateral mass and C2 pars screws. This was followed by bony foramen magnum decompression without duraplasty to address the Chiari malformation. Postoperatively, the patient showed significant improvement in her weakness and cerebellar signs. Postoperative CT and MRI obtained 1 month later showed craniovertebral re-alignment with decompression of the cervicomedullary junction, resolution of syrinx, and tonsillar ascent [Figures 10–12].

Bottom Line: CT of the cranioveretebral junction was the key to the diagnosis of this anomaly.All patients improved during follow up.Proatlas segmentation defects are rare anomalies of the craniovertebral junction.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, Madurai Medical College, Madurai, Tamil Nadu, India.

ABSTRACT

Objective: Proatlas segementation anomalies are due to defective re-segmentation of the proatlas sclerotome. These anomalies of the craniovertebral junction are rare and have multiple presentations. The aim of this study is to report this author's personal experience in managing five of these patients with different radiological findings necessitating different surgical strategies and to provide a brief review of the relevant literature.

Materials and methods: Five patients, all in the second decade of life were treated between 2010 and 2013. There were three males and two females. All the patients presented with spastic quadriparesis and/or cerebellar signs. Patients underwent plain radiographs, MRI and CT of the craniovertebral junction. CT of the cranioveretebral junction was the key to the diagnosis of this anomaly. Postoperatively, patients were assessed with plain radiographs and CT in all patients and MRI in one.

Results: Two patients underwent craniovertebral realignment with occipitocervical fixation, two patients underwent C1-C2 fixation using Goel-Harms technique and one patient underwent craniovertebral realignment with C1-C2 fixation using spacers in the atlanatoaxial joint and foramen magnum decompression. All patients improved during follow up.

Conclusions: Proatlas segmentation defects are rare anomalies of the craniovertebral junction. Routine use of thin section CT of the craniovertebral junction and an awareness of this entity and its multivarious presentations are necessary for clinicians dealing with abnormalities of the craniovertebral junction.

No MeSH data available.


Related in: MedlinePlus