Results and limits of posterior cranial vault expansion by osteotomy and internal distractors

Abstract

Background:Expanding the posterior cranial vault has become a common procedure in the treatment of complex craniosynostosis. Several techniques are available to remodel the posterior vault. Aim of this study was to analyze the posterior vault distraction osteogenesis.Methods:Between 2011 and 2014, 21 children (12 boys) were operated on for a posterior distraction of the cranial vault. The mean age was 8.6 months (minimum, 3 months; maximum, 15 years). Thirteen patients presented a craniofacial syndrome. Five had already been operated on (two anterior cranial surgery, two suboccipital decompression, and one craniotomy for sagittal synostosis). Raised intracranial pressure (ICP) was present in 6 patients. Seven patients had symptomatic cerebellar tonsils herniation (TH).Results:In 17 children, 2 lateral distractors were placed, in 3 a 3rd medial distractor was placed, and in 1 child 4 distractors were implanted. Volumetric analysis based on computed tomography showed a mean increase of volume of 13.9% 117 days later. After the distraction, symptoms related to raised ICP or TH were improved in all patients, however, radiologically TH was improved at the last follow-up in 54% of the cases.Conclusion:Posterior cranial vault distraction is an efficacious technique to enlarge the posterior skull vault and treat increased ICP. Moreover, it appears to be efficacious in treating TH-related symptoms.

Extended experience in parieto-occipital expansion surgery by meander technique—clinical and radiological evaluation

“…Thus, it was suggested to perform the expansion together with a decompression of the craniocervical junction in the same session [ 24 ]. Di Rocco et al described a good resolution of Chiari symptomatology , but not necessarily an early radiological improvement, similarly to our results [ 25 ]. Interestingly, later MRI follow-ups showed actually some radiological improvement of the tonsillar descent (Fig.…”

“…First is the ongoing dynamic changes which are present even after surgery especially if the children have complex malformations or are still very young, and secondly, the expansion technique of the occipito-parietal vault does not affect too much the tonsillar herniation by itself. This has also been reported previously by others using the same [ 27 ] and other techniques [ 25 , 34 ]. Thus, it was suggested to perform the expansion together with a decompression of the craniocervical junction in the same session [ 24 ].…”

“…These rates appears to be decent in comparison to distractive methods, as demonstrated by a review by Greives et al (22.6%) [ 30 ]. The technique of osteogenic distraction appears to be associated with higher rates of infection (7.4–29%) [ 1 , 17 , 22 , 25 , 28 , 31 , 32 ], failure of the implants used for the fixation with loosening or dislocation of its components (0–12%) [ 1 , 32 , 33 ], and dural tears (6.5–10%) [ 30 – 32 ]. A possible advantage of the distraction technique is the shorter surgery time and a limited blood loss with consecutive lower transfusion rate [ 17 ].…”

“…Concerning the gain in intracranial volume , a few results after posterior cranial vault distraction were published in the last few years. Some authors reported their outcomes in terms of volume only on distracted children, in a range of 10.2% and 28.5% volume gain [ 18 , 19 , 25 ]. In studies in which both techniques were compared, 25% volume increase in the distraction technique could be achieved, while posterior remodeling showed up to 29% [ 11 , 17 ].…”

“…Another important factor might be the radiological development of tonsillar descent, if present. However, secondary Chiari conditions might not necessarily respond to a posterior cranial vault decompression [24,25]. For that reason, a suboccipital foramen magnum decompression together with the parieto-occipital remodeling was also discussed [26][27][28].…”