Surgical efficacy evaluation of a modified Melbourne method in treatment of sagittal synostosis

doi:10.21203/rs.3.rs-2063022/v1

Download PDF

Research Article

Surgical efficacy evaluation of a modified Melbourne method in treatment of sagittal synostosis

https://doi.org/10.21203/rs.3.rs-2063022/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Purpose To evaluate the efficacy of a modified Melbourne surgery technique in the treatment of pediatric sagittal synostosis in Chinese population.

Methods Thirty-seven sagittal synostosis patients who received surgery in the Children’s Hospital of Nanjing Medical University, Department of Neurosurgery, from January 2015 to January 2020 were analyzed in this study. Here we reconstruct patients’ CT scan images from pre- and post-operation and control groups. Then the data of ICV, CI, anterior skull height, posterior skull height, and biparietal diameter were analyzed using the paired t-test or Wilcoxon matched-pairs signed-ranks test.

Result The age of these patients was 28.33±11.54 months. After surgery, in the modified group, the average ICV was enlarged from 1280.95±136.06 to 1431.79±138.17 cm3 (P<0.001), the average CI was increased from 0.70±0.05 to 0.79±0.03 (P<0.001). The average anterior skull height, posterior skull height, and biparietal diameter were change from 99.39±4.52 mm, 83.96±5.97 mm, and 111.67±9.48 mm to 87.89±3.81 mm, 107.47±8.61 mm, and 134.15±7.18 mm after surgery (P<0.001, P=0.03, P<0.001, respectively). The average anterior tilt angle and posterior tilt angle were change from 33.75±3.94° and 25.73±5.25° to 16.56±3.59° and 14.14±3.45° after surgery (P<0.001, P<0.001, respectively).

Conclusion The modified Melbourne method is a safe and effective surgical method to treat older children or children with severe sagittal synostosis.

Craniosynostosis

Sagittal synostosis

Modified Melbourne method surgery

Computer-aided 3D reconstruction

Sagittal synostosis is the most common type of nonsyndromic craniosynostosis, with an incidence of approximately 1/2000 [7, 12]. Due to the premature closure of the sagittal suture, the growth of the parietal bone perpendicular to the sagittal suture is restricted. As a result, the biparietal diameter is short, with compensatory increases in the anteroposterior diameters. The main clinical manifestation is scaphocephaly, but it is often accompanied by frontal and occipital enlargement, small biparietal diameter, narrowing of the bilateral temple, and an anterior shift of the vertex of the skull (Fig. 1A) [9].

The Melbourne method of total cranial vault reconstruction (TCVR) was proposed by Greensmith et al. [3] in 2008. This surgical method reconstructs the whole skull of older children and children with severe skull deformity. It can eliminate all deformities of sagittal synostosis and can be used to create a head shape more similar to that of normal children [6, 13, 14]. Between 2010 and 2017, we used the Melbourne method to treat some children with sagittal synostosis and analyzed their postoperative data. We noticed that this procedure can lead to a satisfactory head shape, but it still cannot solve the deformity of the child's frontal enlargement, the anterior skull height, or the skull base deformity.

Therefore, we have modified this procedure. This article discuss our surgical experience with a modified Melbourne technique in the treatment of children with sagittal synostosis in recent years in the Department of Neurosurgery, Children's Hospital of Nanjing Medical University. Computer-aided 3D reconstruction was used to measure the characteristic parameters of the skull before and after surgery. We compared the modified Melbourne procedure with the unmodified Melbourne procedure to assess its corrective effect in children with sagittal synostosis.

Clinical data

We retrospectively analyzed the clinical data of children with sagittal synostosis who were treated in the Department of Neurosurgery, Children's Hospital of Nanjing Medical University from January 2015 to January 2020. (1) The inclusion criteria were as follows: Children diagnosed with sagittal synostosis by head computed tomography (CT) in our hospital and with typical clinical manifestations of sagittal synostosis; children undergoing the Melbourne method of TCVR or modified Melbourne method of TCVR; children aged 14 years or less; children with isolated nonsyndromic sagittal synostosis but without other deformities; and children with complete pre- and postoperative digital images. (2) The exclusion criteria were as follows: children with incomplete imaging data; children with multiple cranial synostoses or other, accompanying malformations; and children with sagittal synostosis who underwent other surgical methods. Control selection: In reference to the children undergoing the modified Melbourne method of TCVR who were included in this study, we utilized a 1:2 ratio to select the in-hospital patients as controls, following strict matching of age, sex, and weight. Other baseline data are shown on Table 1. The implementation of this study has been approved by the Clinical Ethics Committee of the Children’s Hospital of Nanjing Medical University. All patients were informed and signed the informed consent form for the procedure.

Procedure of the modified Melbourne method of TCVR

Under successful anesthesia, the child was placed in the prone position with elevation of the head (Fig. 3A). The surgical field was disinfected with iodine and alcohol and draped. A 20-cm coronary incision was used. The incision was located in the posterior third of the parietal area. The scalp flaps were dissected toward the frontal and occipital regions until reaching the supraorbital rim and the site 2 cm below the external occipital protuberance, respectively, to expose the frontal and occipital surgical fields. After drilling the holes in the bilateral temporal portion, a 1.5-cm-wide and 12-cm-long bone strip crossing the sagittal sinus was made by craniectomy behind the coronal suture. At the sagittal suture, a 2.5-cm longitudinal bone strip was made by craniectomy, which extended posteriorly to the enlarged parietal and occipital region above the external occipital protuberance to form a parietal and occipital bone flap with the sagittal suture. In the biparietal region, an 8 cm × 6 cm bone flap was made by craniectomy. A frontal flap was made by craniectomy at the site 1.0 cm above the supraorbital rim. Barrel stave osteotomy of the occipital bone and greenstick fracture toward the frontal part were performed. The sagittal suture–crossing parietal bone strip was affixed to the occipital bone. The parietal and occipital bone flap with the sagittal skull suture had its occipital edge made into a petal shape and was affixed to the sagittal suture–crossing parietal bone strip. A longitudinal incision was made in both sides of the temporal bone at the depression sites, and barrel stave osteotomy of the temporal bone was done laterally to expand the cranial cavity at the base of the skull. A wedge-shaped osteotomy was performed to shorten the frontal bone flap, which was made into a petal-shaped segment, tilted posteriorly, and affixed to the supraorbital ridge. After the cranial cavity was enlarged laterally with shortening of the anteroposterior diameter, the biparietal bone flaps were trimmed and affixed to the respective biparietal defect sites of the skull. A subperiosteal drainage tube was placed, and the incisions in the temporalis muscle, periosteum, galea aponeurotica, and skin were closed in layers (Figs. 1F, 2A-C and 3D). During the operation, an absorbable fixation system (Synthes GmbH, Switzerland) was used for skull fixation.

Postoperative efficacy evaluation

The parameters for postoperative efficacy evaluation mainly included calculation of total intracranial volume (ICV), cephalic index (CI), anterior skull height, posterior skull height, biparietal diameter, anterior tilt angle, and posterior tilt angle. Mimics 20.0 software (Materialise Inc, Belgium) was used for imaging reconstruction from the thin-slice CT images (DICOM format) of each child's skull [10]. The ICV was calculated based on the Cavalieri principle. From the cranial vertex to the foramen magnum, the ICV was obtained by multiplying the total area of the thin CT slices by the slice thickness. CI is an important indicator to reflect changes in skull shape. Thin-slice cranial CT data of children before and after surgery were three-dimensionally reconstructed on the computer, and the regional growth plug-in was used to extract the skull model. The measure plane where the orbitomeatal line was located was selected as the base plane (Fig. 1). The anterior skull height was defined as the distance from the intersection of the coronal suture and the sagittal suture to the base plane. The posterior skull height was defined as the distance from the intersection of the lambdoid suture and the sagittal suture to the base plane. The biparietal diameter was defined as the longest distance between the bilateral skull bones. The anterior and posterior tilt angles were defined as the angles between the vertical lines of the base plane (from the points where the coronal suture and the lambdoid suture interacted with the sagittal suture) and the tangent lines of the convex surface of the frontal or occipital regions (Fig. 1). All lengths were measured using Mimics 20.0 on the skull model. All the above measurements were made three times, and their average value was used for the statistical analysis.

Statistical methods

The paired t test or Wilcoxon’s signed rank test was used to statistically analyze the measured data of children before and after surgery and the measured data of the control group. The two-sample t-test was used to statistically analyze the preoperatively and postoperatively measured data of the two surgical methods. SPSS 20.0 was used to statistically analyze the measured ICV, CI, anterior skull height, height of the skull vertex, and biparietal diameter and to obtain the corresponding P values. P<0.05 was considered statistically significant.

General data of patients and controls

We retrospectively analyzed the clinical data of children with sagittal synostosis who were treated in the Department of Neurosurgery, Children's Hospital of Nanjing Medical University, from January 2015 to January 2020. After patients with incomplete imaging data or concurrently with other deformities were excluded, a total of 37 children who met the inclusion criteria were included in the statistical analysis. Six of them underwent the unmodified Melbourne method of TCVR (unmodified group), including four boys and two girls (male-to-female ratio 2:1). Their age at surgery was 28.33±11.54 months (range: 17-48 months). Thirty-one patients underwent the modified Melbourne method of TCVR (modified group), including 27 boys and four girls (male-to-female ratio 6.75:1). Their age at surgery was 25.58±9.57 months (range: 13-48 months). No neurological complications were noted in any children after surgery. The children who were treated in our hospital due to mild head trauma during the same time period were selected as the control group for the modified Melbourne technique group (modified control group). The CT results of all the children in the control group were within the normal limits, and their growth development was normal. Children with other diseases were excluded. Each patient undergoing the modified procedure was matched with controls at a ratio of 1:2. A total of 62 inpatient controls, including 54 boys and 8 girls, met the inclusion criteria and were included in the statistical analysis (Table 1).

The modified Melbourne method of TCVR significantly increases the ICV of children with sagittal synostosis

In the unmodified group, the postoperative average ICV (1556.35± 141.06 cm³) was significantly higher than the average preoperative ICV (1405.6±153.52 cm³) (P<0.001). In the modified group, the postoperative average ICV (1431.79±138.17 cm³) was also significantly higher than the average preoperative ICV (1280.95±136.06 cm³) (P<0.001). The average ICV of the modified control group was 1260.09±93.09 cm³. The average increase in the ICV was 150.75±35.15 cm³in the unmodified group vs. 150.84±53.05 cm³in the modified group (P=0.99). There was no significant difference in the ICV between the modified group and the modified control group before surgery (P=0.44), but the postoperative ICV of the modified group was significantly higher than the ICV of the modified control group (P<0.001) (Table 2).

The modified Melbourne method of TCVR effectively improves the CI of children with sagittal synostosis

The average CI in the unmodified group was 0.67±0.03 before surgery and 0.73±0.02 after surgery, for an increase of 8.95%. The average CI of the modified group was 0.70±0.05 before surgery and 0.79±0.03 after surgery, for an increase of 12.86%, which was significantly higher than the CI in the unmodified group. The average CI of the modified control group was 0.82±0.03. The postoperative CI of children with sagittal synostosis was greater than the preoperative one in the unmodified and modified groups (P<0.01, P<0.001, respectively). The preoperative CI of the modified group was significantly lower than that of the modified control group (P<0.001). The postoperative CI of the modified group was still lower than that of the modified control group (P=0.0015), but the postoperative difference between the two groups was significantly less than the preoperative difference between them (Table 2).

Changes in anterior skull height, posterior skull height, and biparietal diameter in children with sagittal synostosis undergoing modified TCVR

In the unmodified group, the average anterior skull height, posterior skull height, and biparietal diameter was 98.2±3.01 mm, 74.67±3.4 mm, and 94.99±7.07 before surgery, respectively, and 100.55±3.32 mm, 89.87±3.45 mm, and 105.54±7.32 mm after surgery. The posterior skull height increased by an average of 15.2 mm (P<0.001), and the biparietal diameter increased by an average of 5.56 mm (P<0.001). In the modified group, the average anterior skull height, posterior skull height, and biparietal diameter were 99.39±4.52 mm, 83.96±5.97 mm, and 111.67±9.48 mm before surgery, respectively, and 87.89±3.81 mm, 107.47±8.61 mm, and 134.15±7.18 mm after surgery. The reduction in anterior skull height, increase in posterior skull height, and increase in biparietal diameter were significantly higher in the modified group than the unmodified group (P<0.001, P=0.03, P<0.001, respectively). The average anterior skull height, posterior skull height, and biparietal diameter were 89.00±2.02 mm, 110.09±6.53 mm, and 136.48±4.33 mm in the modified control group, respectively. The preoperative anterior skull height was significantly higher in the modified group than the modified control group (P<0.001), the preoperative posterior skull height was significantly lower in the modified group than the modified control group (P<0.001), and the preoperative biparietal diameter was shorter in the modified group than the modified control group (P<0.001). In the modified group, the anterior skull height was reduced by 11.5 mm (P<0.001) after surgery compared to before surgery, the average posterior skull height was increased by 23.51 mm (P<0.001), and the average biparietal diameter was increased by an average of 22.48 mm (P<0.001). These final values were not significantly different between the modified group and the modified control group (P=0.15, P=0.12, P=0.13, respectively) (Table 2).

Changes to the anterior tilt angle and posterior tilt angle in children with sagittal synostosis who underwent the modified Melbourne method of TCVR

The average anterior tilt angle and posterior tilt angle in the unmodified group were 30.49±1.48° and 26.12±1.74° before surgery and 28.54±3.17° and 17.54±1.03° after surgery, for average reductions of approximately 1.95° and 8.58°, respectively. In the modified group, the average anterior tilt angle and posterior tilt angle were 33.75±3.94° and 25.73±5.25° before surgery and 16.56±3.59° and 14.14±3.45° after surgery, for approximate average reductions of 17.19° and 11.59°, respectively. The reduction in the anterior tilt angle was more significant in the modified group than in the unmodified group (P<0.001). Although there was no significant difference in the reduction in the posterior tilt angle between surgery groups (P=0.14), the posterior tilt angle in the modified group was still 3.01° higher than that in the unmodified group. In the modified control group, the average anterior tilt angle and posterior tilt angle were 17.4±2.66° and 14.82±2.96°, respectively. The preoperative anterior and posterior tilt angles were significantly greater in the modified group than the modified control group (P<0.001, P<0.001, respectively). The postoperative anterior tilt angle in the modified group was 16.35° less than the preoperative anterior tilt angle (P<0.001) and was not significantly different from that of the modified control group (P=0.31). The postoperative average posterior tilt angle in the modified group was 11.59° less than the preoperative posterior tilt angle (P<0.001) and was not significantly different from that of the modified control group (P=0.45) (Table 2).

Sagittal synostosis is the most common type of nonsyndromic craniosynostosis. Research shows that sagittal synostosis accounts for approximately 55–60% of all craniosynostosis, with a male-to-female ratio of approximately 4:1 [4]. A retrospective analysis of children with craniosynostosis who were treated in our department, in 2019 shows that sagittal synostosis accounted for approximately 50.81% of all craniosynostoses in children, and that the children who underwent the modified Melbourne method of TCVR accounted for approximately 30.95%. This article retrospectively analyzed the clinical data of the modified Melbourne technique in the treatment of sagittal synostosis in children and discussed the surgical procedure and timing, the modification of the Melbourne procedure, and the evaluation of postoperative efficacy.

Since the end of the nineteenth century, when Lannelongue et al. and Lane et al. proposed strip craniectomy to treat sagittal synostosis, a variety of surgical methods for the treatment of sagittal synostosis have been proposed, but after many years of clinical practice, most of the surgical methods have been abandoned due to poor efficacy [1]. In terms of choice of surgical method and timing for the treatment of sagittal synostosis, Greensmith et al. [3] suggested that although there are many surgical methods for sagittal synostosis, the surgical principles can be divided into the following three categories: 1. Lower the local cranial pressure caused by sagittal synostosis, use the subsequent growth and development of the brain to support the skull, and then change the skull shape (such as by strip craniectomy, expanded strip craniectomy, endoscopic-assisted strip craniectomy). 2. Use active or passive force to eventually increase the biparietal diameter, and then reduce the anteroposterior diameter of the skull (such as by pi-plasty and spring-assisted cranioplasty). 3. Use TCVR to change the patient’s skull shape (the change in skull shape can be seen immediately after surgery). TCVR can be used to correct the frontal and occipital enlargement and to increase the posterior skull height, restoring the normal position of the vertex of the skull. Moreover, the osteogenesis and plasticity of the skull of older children are inferior to those of babies. The bone loss in TCVR is very small, so this is suitable for the treatment of older children or children with severe sagittal synostosis. However, this procedure is associated with greater trauma and significantly higher blood loss than other procedures. Greensmith et al. [3] suggests that it is suitable for children older than 6–12 months or children who weigh at least 8 kg. According to our clinical experience with this procedure in recent years, its risk is relatively low if the child is more than 18 months old. In the case with severe skull deformity, the age limit can be less strict if the child can tolerate surgery [3].

The Melbourne method of TCVR was first proposed by the Melbourne Craniofacial Unit in Australia in 2008. It is a complete surgical method for total skull reconstruction. It can effectively solve various deformities in sagittal synostosis. However, this procedure still has room for improvement. (1) In terms of management of frontal enlargement, the unmodified technique can increase the frontal width to reduce the frontal enlargement but cannot significantly improve the anterior skull height and anterior tilt angle. The anterior skull height and frontal enlargement are two of the main deformities of sagittal synostosis, so fixing these is very important to improve the skull shape in children after surgery. (2) Children with sagittal synostosis usually have a narrow base of the middle cranial fossa in the temporal region. For the deformity of the temporal region, the unmodified procedure does not include either correction of this deformity or biparietal bone strip craniectomy, so it is difficult to significantly expand the volume of the skull base to relieve the high local cranial pressure. (3) In terms of posterior skull height, the unmodified procedure cannot sufficiently increase the posterior skull height and cannot sufficiently move the vertex of the skull to the posterior parietal region (Fig. 1C).

Therefore, in our many-year clinical practice, the following modifications have been made to this procedure to make it more suitable for the aesthetics of the Chinese population. The modified procedure is more convenient and safe to carry out in clinical practice. First, as for the surgical position of the child, the Melbourne Craniofacial Unit chose the supine position, and head rotation to the left or right is needed to facilitate the operation in the occipital region. In 2018, James et al. [14] odified this procedure by performing it in two steps under one bout of anesthesia: management of the frontal bone flap and parietal bone flap in the supine position and management of the occipital bone flap in the prone position. The incision is temporarily closed between positionings. The positioning in these two studies can hinder the simplicity and sterility of the surgical operation and greatly limit the scope of surgical exposure. To overcome this, we chose the prone position with elevation of the head (Fig. 3A), using the headrest to lift the head of the prone child. The head should be as high as approximately 20 cm above the heart plane to reduce intracranial pressure and intraoperative bleeding. In addition, nasal intubation is recommended for this position. The tracheal tube should properly secure to avoid intraoperative tracheal tube displacement. Second, for the intraoperative bone flap design, Greensmith et al. [3] and James et al. [7] chose to retain the bilateral skulls at the coronal suture and to perform the frontal flap pasty. Our results have shown that that the anterior skull height and anterior tilt angle are significantly greater in older children with sagittal synostosis than in children in the control group. Therefore, for the management of frontal bone flaps, we suggest performing wedge osteotomy above the supraorbital ridge to obtain a 1.5-cm frontal bone strip. Compared with the unmodified surgery, wedge osteotomy can not only fixate the frontal bone in the posterior tilting position but restore the anterior tilt angle and effectively reduce the anterior skull height and restore the position of the vertex of the skull (Fig. 1B and F). However, the treatment of the frontal bone flap with the unmodified technique is too simple to effectively solve the deformity of the forehead. Third, in terms of management of bilateral coronal sutures, in the unmodified surgery, the bilateral coronal suture is retracted inferiorly to fixate to the frontal flap. We suggest not preserving the bilateral coronal sutures for the following reasons: (a) Temporal constriction is a feature of deformity in older children with sagittal synostosis. Temporal constriction is not only manifested in the parietal and temporal bones, but the bone development of the skull base is also affected. Therefore, strip ostectomy with bilateral coronal suture can provide space to longitudinally open the skull at the skull base on both sides of the temporal cavity to expand the barrel stave osteotomy laterally to the cranial cavity at the base of the skull. Compared with the unmodified surgery, this method can expand the volume of the skull base to the fullest extent and to relieve local intracranial high pressure, and it is helpful to increase the circulation of cerebrospinal fluid in the subarachnoid space. (b) The harvested bone strip with a bilateral coronal suture can be transposed and affixed onto the occipital part. This not only can increase the posterior skull height but also can effectively increase the ICV to relieve local intracranial high pressure. Figure 1C shows that the unmodified surgery did not raise the skull height enough to restore the normal shape of the skull, whereas the wedge-shaped bone strip of the frontal bone and the bone strip with bilateral coronal suture, which were superimposed and affixed onto the occipital bone, could significantly increase the posterior skull height. The skull shape of the children returned mostly to normal after operation (Fig. 1B). (c) Bone strip osteotomy with bilateral sutures can shorten the anteroposterior diameter of the skull and play an important role in increasing the CI.

This study compared the surgical effects of the unmodified and modified Melbourne reconstruction methods in terms of ICV, CI, anterior skull height, height of the skull vertex, biparietal diameter, anterior tilt angle, and posterior tilt angle to provide a reference for improvement of the procedure. In terms of the ICV in children with sagittal synostosis, previous studies have been controversial. Different authors have reported that the ICV in children with sagittal synostosis is greater than, less than, or equal to that of the normal population [2, 5, 11]. Lee et al. [8] suggested that the controversy may be caused by the unmatched age of children in these studies. In this study, the children with sagittal synostosis had a similar preoperative ICV as the control group. However, considering that children with sagittal synostosis had a significantly lower preoperative CI than the control group and obvious temporal constriction, the local ICV in children with sagittal synostosis might be smaller than the control group, so their local intracranial pressure might increase. This is also a possible reason for the delayed language function of some children [15]. Although the anteroposterior diameter is shortened after surgery, the ICV was still significantly higher than that before surgery. This was mainly due to the partial compensation space obtained after increasing the posterior skull height (Fig. 1B), which plays a significant role in relieving intracranial pressure[16]. In this study, we improved the average CI in children with sagittal synostosis from 70–79% through modified Melbourne reconstruction. This was significantly higher than the CI from the unmodified Melbourne reconstruction. Among the 31 patients in the modified group, only three patients had lower-than-normal CI, and the CI returned to normal in 90.32% of them. Even in those three patients, their lower-than-normal CI (74% on average) after surgery was significantly higher than that before surgery. This suggests that the modified Melbourne method of TCVR can effectively improve the CI of children and is better than the unmodified procedure. The anterior skull height was significantly higher in children with sagittal synostosis than normal controls, while the posterior skull height and biparietal diameter were lower in children with sagittal synostosis than normal controls. This indicates that the plan before surgery needs to include lowering the anterior skull height, increasing the posterior skull height, and adjusting the vertex of the skull to the joint of the sagittal suture and the lambdoid suture to restore the normal curvature of the vertex of the skull and the normal skull shape.

The shortcomings of this study are follows: (1) This was a small study. Most of the children had undergone cranial CT examination at the time of diagnosis in other local hospitals. To reduce the radiation exposure of the children, we did not repeat CT before surgery. Therefore, a majority of patients could not be included in this study due to incomplete DICOM data. (2) There were few follow-up data. During the follow-up, if the child's skull shape was satisfactory, to reduce the radiation exposure of the child, we intended to reduce the number of cranial CT scans. Therefore, it was difficult to analyze the follow-up data of children with statistical methods. (3) There were few control cases. In the future study, we will try to recruit more patients to fit the curve of the normal children's CI and reduce the error. (4) The unmodified Melbourne method group was small. The major reason is that we stopped performing the unmodified procedure after starting the modified procedure.

In summary, the Melbourne skull reconstruction method has been fully improved as the modified Melbourne method. The effectiveness of surgical treatment, the scope of exposure of surgical field, and the simplicity and safety of surgery have been significantly improved. It is a safe and effective surgical method to treat older children or children with severe sagittal synostosis. In clinical practice, the surgical plan for sagittal synostosis should be formulated according to the clinical manifestations of the child, the features of the sagittal synostosis, and the severity of the deformity to choose the best procedure and individualize the treatment plan.

Ethics approval and consent to participate The implementation of this study has been approved by the Clinical Ethics Committee of the Children’s Hospital of Nanjing Medical University (201908226-1). All patients were informed and signed the informed consent form for the procedure.

Consent for publication Written informed consent was given by patients, parents, or referring physicians. All patients, parents and authors gave their consent for publication.

Availability of data and material All data generated or analysed during this study are included in this published article

Funding This work was supported by Nanjing Medical Technology Development Fund (YKK16189)

Competing Interests The authors have no relevant financial or non-financial interests to disclose.

Author contributions Qing Yan and Lei Zheng conceived the study, Qing Yan and Zhe Gao acquired the data, Lei Zheng carried out the statistical analysis, Qing Yan, DeZhi Qiu and XianLi Zhang interpreted the findings. Gang Wang performed all surgery, SongMing Huang and Gang Wang revised the manuscript for final submission. All authors read and approved the final manuscript.

Acknowledgements We would like to thank all doctors, nurses and healthcare workers who contributed to the care of patients in Department of Neurosurgery, Children’s hospital of Nanjing Medical University.

Bonfield CM, Lee PS, Adamo MA, Pollack IF (2014) Surgical treatment of sagittal synostosis by extended strip craniectomy: cranial index, nasofrontal angle, reoperation rate, and a review of the literature. J Cranio-Maxillofac Surg 42:1095–1101. https://doi.org/10.1016/j.jcms.2014.01.036
Fischer S, Maltese G, Tarnow P, Wikberg E, Bernhardt P, Tovetjärn R, Kölby L (2014) Intracranial volume is normal in infants with sagittal synostosis. J Plast Surg Hand Surg 49:62–64. https://doi.org/10.3109/2000656x.2014.971804
Greensmith AL, Holmes AD, Lo P, Maxiner W, Heggie AA, Meara JG (2008) Complete correction of severe scaphocephaly: the melbourne method of total vault remodeling. Plast Reconstr Surg 121:1300–1310. https://doi.org/10.1097/01.prs.0000304592.56498.d6
Heliövaara A, Leikola J, Koljonen V, Vuola P, Koivikko M (2017) Length of synostosis and segmented intracranial volume correlate with age in patients with non-syndromic sagittal synostosis. Child's Nerv Syst 34:511–515. https://doi.org/10.1007/s00381-017-3628-2
Heller JB, Heller MM, Knoll B, Gabbay JS, Duncan C, Persing JA (2008) Intracranial volume and cephalic index outcomes for total calvarial reconstruction among nonsyndromic sagittal synostosis patients. Plast Reconstr Surg 121:187–195. https://doi.org/10.1097/01.prs.0000293762.71115.c5
Hughes CD, Isaac KV, Hwang PF, Ganske I, Proctor MR, Meara JG (2018) Modification of the melbourne method for total calvarial vault remodeling. Plast Reconstr Surg Glob Open 6: e1848. https://doi.org/10.1097/GOX.0000000000001848
Kolar JC (2011) An epidemiological study of nonsyndromal craniosynostoses. J Craniofacial Surg 22:47–49. https://doi.org/10.1097/scs.0b013e3181f6c2fb
Lee SS, Duncan CC, Knoll BI, Persing JA (2010) Intracranial compartment volume changes in sagittal craniosynostosis patients: influence of comprehensive cranioplasty. Plast Reconstr Surg 126:187–196. https://doi.org/10.1097/prs.0b013e3181dab5be
Malde O, Cross C, Lim CL, Marghoub A, Cunningham ML, Hopper RA, Moazen M (2020) Predicting calvarial morphology in sagittal craniosynostosis. Sci Rep 10:3. https://doi.org/10.1038/s41598-019-55224-5
Maltese G, Tarnow P, Wikberg E, Bernhardt P, Lagerlöf JH, Tovetjärn R, Kölby L (2014) Intracranial volume before and after surgical treatment for isolated metopic synostosis. J Craniofacial Surg 25:262–266. https://doi.org/10.1097/scs.0000000000000423
Seeberger R, Hoffmann J, Freudlsperger C, Berger M, Bodem J, Horn D, Engel M (2016) Intracranial volume (ICV) in isolated sagittal craniosynostosis measured by 3D photocephalometry: a new perspective on a controversial issue. J Cranio-Maxillofac Surg 44:626–631. https://doi.org/10.1016/j.jcms.2016.01.023
Selber J, Reid RR, Chike-Obi CJ, Sutton LN, Zackai EH, McDonald-McGinn D, Sonnad SS, Whitaker LA, Bartlett SP (2008) The changing epidemiologic spectrum of single-suture synostoses. Plast Reconstr Surg 122:527–533. https://doi.org/10.1097/prs.0b013e31817d548c
Seruya M, Tan SY, Wray AC, Penington AJ, Greensmith AL, Holmes AD, Chong DK (2013) Total cranial vault remodeling for isolated sagittal synostosis. Plast Reconstr Surg 132:602e-610e. https://doi.org/10.1097/prs.0b013e31829f4b3d
Sharma JD, O’Hara JL, Borghi A, Rodriguez-Florez N, Breakey W, Ong J, Jeelani NO, Dunaway DJ, James G (2018) Results following adoption of a modified melbourne technique of total scaphocephaly correction. J Craniofacial Surg 29:1117–1122. https://doi.org/10.1097/scs.0000000000004593
van Veelen M-LC, Jippes M, Carolina J-CA, de Rooi J, Dirven CMF, van Adrichem LNA, Mathijssen IM (2016) Volume measurements on three-dimensional photogrammetry after extended strip versus total cranial remodeling for sagittal synostosis: a comparative cohort study. J Cranio-Maxillofac Surg 44:1713–1718. https://doi.org/10.1016/j.jcms.2016.07.029
Waitzman AA, Posnick JC, Armstrong DC, Pron GE (1992) Craniofacial skeletal measurements based on computed tomography: part II. normal values and growth trends. Cleft Palate-Craniofacial J 29:118–128. https://doi.org/10.1597/1545-1569(1992)029<0118:csmboc>2.3.co;2

Table 1. Basic information of children in the modified, unmodified, and control groups

	Modified group	Unmodified group	Control group
Total	31	6	62
Sex
Male	27	4	54
Female	4	2	8
Age (years)
12-23 months	15	2	30
24-35 months	9	2	18
>36 months	7	2	14

Table 2. Cranial parameter statistics between children with sagittal synostosis who underwent the modified Melbourne method of total cranial vault reconstruction and those in the control group

Parameters	Before surgery in the modified group	After surgery in modified group	Before surgery in the unmodified group	After surgery in the unmodified group	Modified control group

Total intracranial volume (cm³)	1280.95±136.06	1431.79±138.17	1405.6±153.52	1556.35±141.06	1260.09±93.09
Cephalic index	0.70±0.05	0.79±0.03	0.67±0.03	0.73±0.02	0.82±0.03
Anterior skull height (mm)	99.39±4.52	87.89±3.81	98.19±3.01	100.55±3.32	89.00±2.02
Posterior skull height (mm)	83.96±5.97	107.47±8.61	74.67±3.4	89.87±3.45	110.09±6.53
Biparietal diameter (mm)	111.67±9.48	134.15±7.18	94.99±7.07	105.54±7.32	136.48±4.33
Anterior tilt angle (degrees)	33.75±3.94	16.56±3.59	30.49±1.48	28.54±3.17	17.40±2.66
Posterior tilt angle (degrees)	25.73±5.25	14.14±3.45	26.12±1.74	17.54±1.03	14.82±2.96

Note: Modified group: The differences between the preoperative and postoperative parameters in the modified group were significant (all P<0.001). The preoperative total intracranial volume was not significantly different (P>0.05) between the modified group and the modified control group, but all other parameters had significant differences (all P<0.001). The postoperative total intracranial volume (p<0.001) and cephalic index (p=0.0015) were significantly different between the modified group and the modified control group, but no significant difference was seen in any other parameter (P>0.05). Unmodified group: There was a significant difference between the postoperative and preoperative values (P<0.001); the anterior skull height after surgery was higher than that before surgery (P=0.002).

No competing interests reported.

Download PDF

Version 1

posted

You are reading this latest preprint version

Surgical efficacy evaluation of a modified Melbourne method in treatment of sagittal synostosis

Status:

Version 1

Abstract

Figures

Introduction

Methods

Results

Discussion

Declarations

References

Tables

Additional Declarations

Status:

Version 1