Total Cranial Vault Remodeling Using Multidirectional Cranial Distraction Osteogenesis in Craniosynostosis

The authors¹ of the article entitled “Total Cranial Vault Remodeling Using Multidirectional Cranial Distraction Osteogenesis in Craniosynostosis,” published in this issue of Plastic and Reconstructive Surgery – Global Open, are to be commended for their use of novel hardware and a customized multivectorial distraction technique, which results in multidimensional intracranial volumetric expansion in craniosynostosis.

The authors’ reported technique represents yet another noteworthy development in the continuing evolution of distraction osteogenesis in craniofacial surgery, following mandible distraction osteogenesis, initially conceptualized and designed by McCarthy et al,² and monobloc frontofacial advancement using distraction osteogenesis, designed by a multidisciplinary team at SOBRAPAR Hospital led by the late Raposo do Amaral.³

The 2 principal goals of craniosynostosis surgery are to address a wide variety of morphometric characteristics and alleviate elevated intracranial pressure (ICP).⁴ In cases where this type of surgery is performed on patients with severe syndromic characteristics, accompanying conditions such as obstructive sleep apnea and malignant exorbitism must also be considered before a specific surgical technique is selected.

Determining the precise intracranial volume required to alleviate symptoms of elevated ICP presents a complex challenge. This question is difficult to address comprehensively, as it necessitates customization based on the patient’s specific diagnosis, the type of craniosynostosis, and, potentially, the genetic mutation involved. It is well-established that certain types and variant patterns are more strongly associated with elevated ICP.⁵

To determine the effectiveness of functional outcomes of the authors’ multivectorial distraction technique, it would be helpful to the readership if the authors provide data regarding the examination and assessment of the prevalence of Chiari malformation and papilledema in this patient population via radiological and ophthalmologic screening.

In the article, data were gleaned from patients presenting a variety of conditions due to nonsyndromic single-suture craniosynostosis to syndromic craniosynostosis, including Pfeiffer syndrome. Patients with severe Pfeiffer syndrome (type II or III) typically present Swiss cheese–like bone formation. The patient with Pfeiffer syndrome referenced by the authors had previously been provided with a ventriculoperitoneal shunt, as revealed by computed tomography imaging. This patient previously underwent unsuccessful posterior vault distraction osteogenesis as an initial surgical procedure. Subsequently, the authors performed multivectorial distraction osteogenesis as a secondary procedure and achieved a satisfactory outcome.

In our clinical practice, as well as in others, the primary intervention for patients with Pfeiffer syndrome who display a similar ossification pattern is the early expansion of the cranial vault achieved through extensive craniectomies, followed by reconstruction aimed at releasing and expanding areas of significant skull constriction.^6,7 We posit that the bone in this scenario is so fragile that it becomes prone to hinge-type movement during distraction osteogenesis, thereby posing a high risk of cerebrospinal fluid leakage. A ventriculoperitoneal (VP) shunt is only performed following the bony surgery, unless there is significant progression in ventricular size and hydrocephalus(Fig. 1).⁸

Fig. 1.

A Pfeiffer syndrome type II patient. A, Preoperative lateral photograph of a patient with Pfeiffer syndrome type II who developed progressive and rapid ventricular expansion with hydrocephalus, requiring a VP shunt. B, Postoperative lateral photograph of the same patient following shunt placement and before craniectomy for release of areas of bone constriction. C, Postoperative lateral photograph of the same patient showing expansion and remodeling of the mid and posterior cranial vault. D, Six-year follow-up lateral view of the same patient demonstrating complete remodeling after a single bony procedure.

The authors may benefit from this guideline and recommendation concerning patients with syndromic craniosynostosis exhibiting Swiss cheese–type bone formation. Additionally, it is worth considering whether multivectorial distraction or any type of distraction could increase the likelihood of cerebrospinal fluid leakage in this particular scenario and whether it should be chosen as primary surgery. In addition, VP shunt mobilization during the distraction should be carefully anticipated to prevent severe complications.

An additional aspect to consider is the extended duration of hospital stay, ranging from 6 to 11 days, with all patients remaining hospitalized during the distraction phase. Considering the average hospital stay of 4 days for posterior vault distraction,⁹ and even a new trend for endoscopic, transfusion-free surgery with a single day of hospitalization for patients with single-suture synostosis, the authors contend that maintaining patients in the hospital for such an extended period would substantially increase both the cost and the burden of care for the family. What specific factors support patients remaining hospitalized during the entire distraction phase?

Additionally, the authors performed daily advancement at a rate of 1.5 mm, which is significantly higher than the 1 mm daily rate currently adopted by the majority of craniofacial surgeons. Is there a specific rationale for this increased rate of advancement?

The relative transfused volume of 48.2 mL/kg is notably greater than that associated with a traditional posterior vault distraction osteogenesis, irrespective of the syndrome type,^9,10 thereby elevating the risk of transfusion-related complications. An elaboration on the threshold and their transfusion protocols by the authors would be advantageous for the readers.

In identifying the primary indicators for multivectorial distraction osteogenesis, it is essential to evaluate whether this technique should be universally utilized as a first-line treatment for all patients, including young primary single suture craniosynostosis, or if it should be specifically reserved for secondary and older adult patients. Establishing robust criteria for the authors’ multivectorial technique indication would facilitate patient screening and enable customization to address specific needs.

The authors are to be congratulated for their innovative multivectorial distraction technique and specially designed and ingenious hardware which have the potential to effectively expand the cranium in multiple dimensions.

DISCLOSURE

The authors have no financial interest to declare in relation to the content of this article.