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Posterior fossa reconstruction: a surgical technique for the treatment of Chiari I malformation and Chiari I/syringomyelia complex--preliminary results and magnetic resonance imaging quantitative assessment of hindbrain migration.
Neurosurgery. 1994 Nov; 35(5):874-84; discussion 884-5.N

Abstract

Experimental models have shown that Chiari I malformation is a primary paraaxial mesodermal insufficiency occurring after the closure of the neural folds takes place. According to these hypotheses, a small posterior fossa caused by an underdeveloped occipital bone would be the primary factor in the formation of the hindbrain hernia. The main objective in the surgical treatment of Chiari I malformation and related syringomyelia is directed to restore normal cerebrospinal fluid dynamics at the craniovertebral junction. The most widely accepted surgical approach is to perform a craniovertebral decompression of the posterior fossa contents with or without a dural graft. It has been emphasized that suboccipital craniectomy should be small enough to avoid downward migration of the hindbrain into the craniectomy. This slump of the hindbrain has been verified by studies using postoperative assessment by magnetic resonance imaging. Our aim in this study is to present a modification of the conventional surgical technique, which we have called posterior fossa reconstruction (PFR). Ten patients were operated on using this technique and compared with a historical control group operated on with the classic approach of making a small suboccipital craniectomy, opening the arachnoid, and closing the dura with a graft. To evaluate the morphological results in both groups objectively, preoperative and postoperative measurements of the relative positions of the fastigium and upper pons above a basal line in the midsagittal T1-weighted magnetic resonance images were obtained. In those cases with syringomyelia, syringo-to-cord ratios were calculated. The mean age of the PFR group was 35 +/- 16 years (mean +/- SD); in the control group it was 35.2 +/- 12 years. In the PFR group, the formation of an artificial cisterna magna was observed in every case; it was observed in only one case in the control group. An upward migration of the cerebellum was seen in all cases in the PFR group, with a mean ascent of the fastigium of 6.2 mm. A significant downward migration of the cerebellum was observed in seven cases in the control group. No significant differences were found in both groups when comparing syringo-to-cord ratios. This leads us to conclude that PFR is more effective than conventional surgical approaches in restoring the normal morphology of the craniovertebral junction. This allows cranial ascent of the hindbrain verified by magnetic resonance imaging and good short-term clinical results. Because PFR is mainly an extraarachnoidal approach, complications related to surgery using this technique can be kept to a minimum.

Authors+Show Affiliations

Neurosurgical Department, Vall d'Hebron University Hospital, Barcelona, Spain.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Comparative Study
Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

7838336

Citation

Sahuquillo, J, et al. "Posterior Fossa Reconstruction: a Surgical Technique for the Treatment of Chiari I Malformation and Chiari I/syringomyelia Complex--preliminary Results and Magnetic Resonance Imaging Quantitative Assessment of Hindbrain Migration." Neurosurgery, vol. 35, no. 5, 1994, pp. 874-84; discussion 884-5.
Sahuquillo J, Rubio E, Poca MA, et al. Posterior fossa reconstruction: a surgical technique for the treatment of Chiari I malformation and Chiari I/syringomyelia complex--preliminary results and magnetic resonance imaging quantitative assessment of hindbrain migration. Neurosurgery. 1994;35(5):874-84; discussion 884-5.
Sahuquillo, J., Rubio, E., Poca, M. A., Rovira, A., Rodriguez-Baeza, A., & Cervera, C. (1994). Posterior fossa reconstruction: a surgical technique for the treatment of Chiari I malformation and Chiari I/syringomyelia complex--preliminary results and magnetic resonance imaging quantitative assessment of hindbrain migration. Neurosurgery, 35(5), 874-84; discussion 884-5.
Sahuquillo J, et al. Posterior Fossa Reconstruction: a Surgical Technique for the Treatment of Chiari I Malformation and Chiari I/syringomyelia Complex--preliminary Results and Magnetic Resonance Imaging Quantitative Assessment of Hindbrain Migration. Neurosurgery. 1994;35(5):874-84; discussion 884-5. PubMed PMID: 7838336.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Posterior fossa reconstruction: a surgical technique for the treatment of Chiari I malformation and Chiari I/syringomyelia complex--preliminary results and magnetic resonance imaging quantitative assessment of hindbrain migration. AU - Sahuquillo,J, AU - Rubio,E, AU - Poca,M A, AU - Rovira,A, AU - Rodriguez-Baeza,A, AU - Cervera,C, PY - 1994/11/1/pubmed PY - 1994/11/1/medline PY - 1994/11/1/entrez SP - 874-84; discussion 884-5 JF - Neurosurgery JO - Neurosurgery VL - 35 IS - 5 N2 - Experimental models have shown that Chiari I malformation is a primary paraaxial mesodermal insufficiency occurring after the closure of the neural folds takes place. According to these hypotheses, a small posterior fossa caused by an underdeveloped occipital bone would be the primary factor in the formation of the hindbrain hernia. The main objective in the surgical treatment of Chiari I malformation and related syringomyelia is directed to restore normal cerebrospinal fluid dynamics at the craniovertebral junction. The most widely accepted surgical approach is to perform a craniovertebral decompression of the posterior fossa contents with or without a dural graft. It has been emphasized that suboccipital craniectomy should be small enough to avoid downward migration of the hindbrain into the craniectomy. This slump of the hindbrain has been verified by studies using postoperative assessment by magnetic resonance imaging. Our aim in this study is to present a modification of the conventional surgical technique, which we have called posterior fossa reconstruction (PFR). Ten patients were operated on using this technique and compared with a historical control group operated on with the classic approach of making a small suboccipital craniectomy, opening the arachnoid, and closing the dura with a graft. To evaluate the morphological results in both groups objectively, preoperative and postoperative measurements of the relative positions of the fastigium and upper pons above a basal line in the midsagittal T1-weighted magnetic resonance images were obtained. In those cases with syringomyelia, syringo-to-cord ratios were calculated. The mean age of the PFR group was 35 +/- 16 years (mean +/- SD); in the control group it was 35.2 +/- 12 years. In the PFR group, the formation of an artificial cisterna magna was observed in every case; it was observed in only one case in the control group. An upward migration of the cerebellum was seen in all cases in the PFR group, with a mean ascent of the fastigium of 6.2 mm. A significant downward migration of the cerebellum was observed in seven cases in the control group. No significant differences were found in both groups when comparing syringo-to-cord ratios. This leads us to conclude that PFR is more effective than conventional surgical approaches in restoring the normal morphology of the craniovertebral junction. This allows cranial ascent of the hindbrain verified by magnetic resonance imaging and good short-term clinical results. Because PFR is mainly an extraarachnoidal approach, complications related to surgery using this technique can be kept to a minimum. SN - 0148-396X UR - https://www.unboundmedicine.com/medline/citation/7838336/Posterior_fossa_reconstruction:_a_surgical_technique_for_the_treatment_of_Chiari_I_malformation_and_Chiari_I/syringomyelia_complex__preliminary_results_and_magnetic_resonance_imaging_quantitative_assessment_of_hindbrain_migration_ L2 - https://academic.oup.com/neurosurgery/article-lookup/doi/10.1227/00006123-199411000-00011 DB - PRIME DP - Unbound Medicine ER -