Bilateral Lambdoid and Sagittal Craniosynostosis with Hydrocephalus: ETV, Bifrontal Craniotomy, Anterior Cranial Vault Remodeling, and Posterior Cranial Vault Expansion
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.319204
Source of Support: None, Conflict of Interest: None
Keywords: Bilateral lambdoid and sagittal craniosynostosis, chiari 1 malformation, endoscopic third ventriculostomy, hydrocephalus, Mercedes Benz pattern craniosynostosis, posterior cranial vault expansionKey Message: Bilateral lambdoid and sagittal craniosynostosis is a rare form of multisutural synostosis. The treatment has to be customized. In a child with hydrocephalus and too much frontal bossing, endoscopic third ventriculostomy and whole cranial vault remodeling give best results.
Bilateral lambdoid and sagittal craniosynostosis (BLSS), also known as Mercedes Benz pattern craniosynostosis, is a rare form of craniosynostosis.,,,, The whole cranial vault remodeling gives the best result. This type of craniosynostosis may be associated with hydrocephalus and Chiari 1 malformation. Endoscopic third ventriculostomy (ETV) has been described for the treatment of hydrocephalus.,
To describe ETV, bifrontal craniotomy, anterior cranial vault remodeling, and posterior cranial vault expansion for BLSS in a case of a 7-month-old child.
The child underwent surgery under general anesthesia in the supine position with head neutral. A zigzag bicoronal scalp incision was made and supraperiosteal dissection was done exposing both frontal bones till 1 cm superior to orbital rims. A precoronal burr hole was made and an external ventricular catheter was inserted, and ICP was monitored for 5 min. Then, using Gaab universal neuroendoscope, standard ETV was done. Bifrontal craniotomy was done. The anteroposterior length of the bifrontal bone was reduced by 1 cm by removing a strip of bone posteriorly. Then, the bifrontal bone flap was fixed both anteriorly and posteriorly to the skull thus reducing the frontal bossing.
The child was turned prone and a linear scalp incision was made from vertex to suboccipital region. Bilateral parietooccipital craniotomy was done, limited by a large emissary vein posteriorly. The posterior bone flap was hinged loosely to the suboccipital bone allowing posterior expansion.
Wounds were closed in two layers.
Video link: https://youtu.be/aHFMEYEoI3o
Video timeline with audio transcript (Minutes)
This is a case of BLSS with hydrocephalus.
00:08: The coronal suture was open and was widely separated. Other major sutures were fused resulting in crowding in the posterior compartment of the cranial vault and hydrocephalus.
00:20: The surgery was done in the supine position with the elevation of the bifrontal scalp flap supraperiosteally. A precoronal burr hole was made and the ventricle punctured. The ICP monitoring showed an ICP of 14 mmHg, which is on the higher side for a 7-month-old child.
01:10: Trocar and endoscope sheath was placed in the ventricle and the third ventriculostomy was done. You can see that the stoma is being dilated. The basilar artery with perforators could be visualized through the stoma.
01:30: After ETV, bifrontal skull flap was marked and a bifrontal craniotomy was done. A 1 cm strip of bone posterior to the coronal suture was removed. The dura was coagulated to decrease the anteroposterior diameter of the skull and reduce the frontal bossing. Barrel staff cuts were made on the frontal skull flap. As the bone was soft, the contouring of the bone was done. It was replaced and tied with sutures, both anteriorly as well as posteriorly. You can see that the bifrontal bossing has significantly reduced after tying the skull flap.
02:47: The child was turned prone. A midline incision was made from the vertex to the suboccipital region. The supraperiosteal dissection was done taking care of the emissary vein, in the inferior part of the incision. Bilateral occipital craniotomy was done above the level of the transverse sinus. Barrel staff cuts were made in the radial direction in the bilateral occipital bone flap. It was hinged to the suboccipital bone for cranial vault expansion posteriorly. The postop scan showed a reduction in bifrontal bossing and expansion of the posterior cranial vault. At follow-up, the MRI showed a reduction in hydrocephalus.
The cosmetic outcome was satisfactory. The ventricular volume and frontal bossing reduced at 6 months of follow-up. The growth and development of child was at par with his age.
Pearls and pitfalls
Surgery in two different positions for frontal bossing and posterior cranial vault expansion provides a wider exposure without undue stretching of the scalp flap. The BLSS results in increased intracranial volume due to hydrocephalus; an ETV can help reduce hydrocephalus and prevent frontal bossing.
The BLSS is relatively rare form of craniosynostosis, and there is no consensus regarding the most appropriate management of this condition. Many surgeons feel that the entire procedure could be performed via a single bicoronal incision with the patient in the modified sphinx prone position. We have attempted this earlier for other synostosis but have found ergonomic difficulties, hence prefer to do it in stages in different positions. Alternative options such as endoscopic approaches for synostectomy are also available. However, we have experienced inferior outcomes with limited procedures. We prefer to do complete cranial vault remodeling for craniosynostosis. However, more extensive surgery may incur more blood loss, blood product transfusions, operative time, length of stay, and complications.
We use methods to mitigate bleeding and blood loss like a preoperative iron supplement and intraoperative tranexamic acid infusion. In this case, there were no significant changes in hemodynamic parameters. We could complete the proposed surgery uneventfully. Recently, virtual surgical planning and premade sterile cutting guides, customized in advance for the individual synostosis patient, have enhanced this approach even further in terms of safety, efficiency, and accuracy of the reconstruction. We do not use this technology as of now though have considered it for complex craniosynostosis. In the case of BLSS, there may be persistent posterior fossa crowding and there may be a need for additional surgery for craniocervical decompression later. In our case, additional surgery was not required.
The whole cranial vault remodeling gives the best result for BLSS, and the addition of ETV at the time of first surgery obviates the need for CSF diversion and treatment of Chiari malformation More Details later.
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