Interobserver and intraobserver reliability of the cervicomedullary angle in a normal adult population

Clinical analysis of atlanto-occipital decompression in the management of chiari malformation with multi-segmental syringomyelia

Background

Chiari malformation type I with syringomyelia (CM-I-S) is a very common disease in neurosurgery. There are also various surgical methods. But it is controversial. There are few reports about children, especially the treatment of multi-segmental beaded syringomyelia. The purpose of this study was to explore the clinical effects of atlanto-occipital decompression (AOD) in the management of Chiari malformation type I (CM-I) with multi-segmental beaded syringomyelia (MSBS) in pediatric patients.

Methods

This retrospective study were pediatric patients with CM-I combined with MSBS who were treated in our hospital from January 2015 to December 2023. The patients who received the AOD treatment were screened according to inclusion and exclusion criteria. Outcomes were assessed by comparison of pre- and postoperative clinical, Chicago Chiari Outcome Scale (CCOS), the diameter and volume of the syringomyelia, morphological parameters of posterior cranial fossa (cervical spinal cord angle of medulla oblongata, CSC-MO) and complications in the enrolled children.

Results

This study ultimately included 21 eligible pediatric patients with CM-I and MSBS. All the patients successfully completed the operation, which consists of atlanto-occipital decompression, partial resection of the posterior arch of the atlas, electrocoagulation of the cerebellar tonsil, pseudomembrane resection of the central canal orifice (latch) of the spinal cord, and artificial dura mater expansion repair. No death, no relapses, no serious neurological dysfunction and other complications. At the last follow-up, the clinical symptoms of all patients basically disappeared. The results of magnetic resonance imaging (MRI) showed that the average preoperative cerebellar tonsillar hernia was 12.4 ± 4.6 mm, and the postoperative were all above the foramen magnum. The average preoperative syringomyelia volume was 11.7 ± 3.7 cm2, and the syringomyelia disappeared or significantly shrunk after operation, with the volume unable to be accurately measured. The median preoperative CSC-MO was 132.5°, and the median postoperative CSC-MO was 150°, with a significant difference. The median preoperative pain and non-pain score of CCOS was 4 and 3 respectively. The symptoms disappeared after operation, and the score was 4. Only 5 children had cerebrospinal fluid leakage.

Conclusion

The AOD is safe and effective in CM-I with MSBS in pediatric patients. Pseudomembrane resection of the central canal orifice (latch) of the spinal cord is crucial for the treatment of syringomyelia.

Establish a new parameter "horizontal view-axial angle" and explore its role in the treatment of atlantoaxial instability diseases

Objective

The objective of the study is to establish a new parameter that can be clearly measured on x-ray images to complement the description of the sagittal alignment of the craniocervical junction. The authors anticipate that this new parameter will enhance surgeons' understanding of the sagittal alignment of the craniocervical junction and play a positive role in the guidance of intraoperative reduction and in the evaluation of postoperative outcomes of patients with atlantoaxial instability.

Methods

From November 2018 to June 2020, a total of 159 asymptomatic subjects who underwent frontal and lateral cervical x-ray examination in the Second Affiliated Hospital of Soochow University were included in the study. Age, gender, previous spinal trauma, and disease history of each subject were recorded. After screening, 127 effective samples were finally obtained. When taking lateral cervical radiographs, all subjects placed their neck in a neutral position and looked straight ahead with both eyes. On the obtained lateral x-ray images, a straight line was drawn from the radix to the anterior clinoid process; another line was made along the posterior edge of the C2 vertebral body; and the angle between the two lines was measured, which was defined as the "horizontal view-axial angle." The angle formed by the tangent of the posterior edge of the C2 vertebra and C7 vertebral body is the "C2-C7 angle," which was used to describe the curvature of the lower cervical vertebra. The normal range of horizontal view-axial angle and its relationship with C2-7 angle were evaluated.

Results

The average C2-C7 angle of male subjects was (14.0° ± 7.4°), while that of female subjects was (11.09° ± 7.36°). The average horizontal view-axial angle of male subjects was (92.79° ± 4.52°), and that of female subjects was (94.29° ± 4.50°). Pearson correlation test showed that there was a significant negative correlation between horizontal view-axis angle and C2-C7 angle.

Conclusions

For patients with atlantoaxial instability diseases, the horizontal view-axis angle is expected to be a sagittal parameter to guide the intraoperative reduction and evaluate postoperative outcomes.

Cervical Spinal Cord Compression and Sleep-Disordered Breathing in Syndromic Craniosynostosis

BACKGROUND AND PURPOSE

Cerebellar tonsillar herniation arises frequently in syndromic craniosynostosis and causes central and obstructive apneas in other diseases through spinal cord compression. The purposes of this study were the following: 1) to determine the prevalence of cervical spinal cord compression in syndromic craniosynostosis, and 2) to evaluate its connection with sleep-disordered breathing.

MATERIALS AND METHODS

This was a cross-sectional study including patients with syndromic craniosynostosis who underwent MR imaging and polysomnography. Measures encompassed the compression ratio at the level of the odontoid process and foramen magnum and the cervicomedullary angle. MR imaging studies of controls were included. Linear mixed models were developed to compare patients with syndromic craniosynostosis with controls and to evaluate the association between obstructive and central sleep apneas and MR imaging parameters.

RESULTS

One hundred twenty-two MR imaging scans and polysomnographies in 89 patients were paired; 131 MR imaging scans in controls were included. The mean age at polysomnography was 5.7 years (range, 0.02-18.9 years). The compression ratio at the level of the odontoid process was comparable with that in controls; the compression ratio at the level of the foramen magnum was significantly higher in patients with Crouzon syndrome (+27.1, P < .001). The cervicomedullary angle was significantly smaller in Apert, Crouzon, and Saethre-Chotzen syndromes (-4.4°, P = .01; -10.2°, P < .001; -5.2°, P = .049). The compression ratios at the level of the odontoid process and the foramen magnum, the cervicomedullary angle, and age were not associated with obstructive apneas (P > .05). Only age was associated with central apneas (P = .02).

CONCLUSIONS

The prevalence of cervical spinal cord compression in syndromic craniosynostosis is low and is not correlated to sleep disturbances. However, considering the high prevalence of obstructive sleep apnea in syndromic craniosynostosis and the low prevalence of compression and central sleep apnea in our study, we would, nevertheless, recommend a polysomnography in case of compression on MR imaging studies.

Reconsideration of the transoral odontoidectomy in complex craniovertebral junction patients with irreducible anterior compression

Background

Although the single-stage posterior realignment craniovertebral junction (CVJ) surgery could treat most of the basilar invagination (BI) and atlantoaxial dislocation (AAD), there are still some cases with incomplete decompression of the spinal cord, which remains a technique challenging situation.

Methods

Eleven patients were included with remained myelopathic symptoms after posterior correction due to incomplete decompression of the spinal cord. Transoral odontoidectomy assisted by image-guided navigation and intraoperative CT was performed. Clinical assessment and image measurements were performed preoperatively and at the most recent follow-up.

Results

Eleven patients were followed up for an average of 47 months. Symptoms were alleviated in 10 of 11 patients (90.9%). One patient died of an unknown reason 1 week after the transoral approach. The clinical and radiological parameters pre- and postoperatively were reported.

Conclusion

Transoral odontoidectomy as a salvage surgery is safe and effective for properly selected BI and AAD patients after inadequate indirect decompression from posterior distraction and fixation. Image-guided navigation and intraoperative CT can provide precise information and accurate localization during operation, thus enabling complete resection of the odontoid process and decompression of the spinal cord.

Craniometric parameters for the evaluation of platybasia and basilar invagination on magnetic resonance imaging: a reproducibility study

Objective

The present study aims to perform a reproducibility study of the clivus-canal angle (CCA), Welcker’s basal angle (WBA), and the distance from the odontoid process to Chamberlain’s line (DOCL) on magnetic resonance imaging (MRI).

Materials and Methods

Two medical students and two radiologists respectively evaluated 100 and 50 consecutive MRI scans of adult skulls, selected randomly. Each examiner, working independently and blinded to the previous results, performed readings for each patient on two different occasions. Measurements were performed in T1-weighted sequences acquired in the midsagittal plane. The levels of intraobserver reproducibility and interobserver agreement were evaluated by calculating the intraclass correlation coefficients (ICCs) and the corresponding 95% confidence intervals.

Results

The mean values obtained by the examiners were 150º for the CCA, 130º for the WBA, and 2.5 mm for the DOCL. The ICC for interobserver agreement was 0.980, 0.935, and 0.967, for the CCA, WBA, and DOCL, respectively, for the students, compared with 0.977, 0.941, and 0.982, respectively, for the radiologists, and 0.980, 0.992, and 0.990, respectively, for all of the examiners together. In the analysis of intraobserver agreement, the ICC ranged from 0.929 to 0.959 for the CCA, from 0.918 to 0.964 for the WBA, and from 0.918 to 0.981 for the DOCL.

Conclusion

The measurement of the CCA, WBA, and DOCL appears to show excellent intraobserver reproducibility and interobserver agreement on MRI.

Anatomical evaluation of the craniovertebral junction on cone-beam computed tomography images

INTRODUCTION

There are many craniometric measurements that are used in evaluating craniovertebral junction (CVJ) pathologies such as basilar invagination, atlantoaxial dislocation and platybasia. Therefore, it is important to determine the normal reference range of the craniometric measurements. This study aims to determine the morphometric reference values of the bony structures in the CVJ from cone-beam computed tomography (CBCT) images of a group of South Eastern Anatolian population.

MATERIALS AND METHODS

The CBCT images of 300 individuals were retrospectively evaluated. 14 parameters on midsagittal and 2 parameters on the coronal plane were studied. The data were statistically evaluated.

RESULTS

Measurement results were found as follows; the distances between odontoid process (OP) and McGregor line as 0.31 ± 3.22 mm, OP and Chamberlain line 1.06 ± 3.22 mm, OP and McRae line 5.30 ± 1.59 mm, OP and Fischgold digastric line 8.70 ± 4.12 mm, OP and Fischgold bimastoid line - 5.15 ± 4.86 mm, length of McRae line 35.58 ± 2.52 mm, atlantodental interval 1.28 ± 0.48 mm, posterior atlantodental interval 19.54 ± 2.24 mm, basion axial interval 4.01 ± 1.83 mm, basion dental interval 4.92 ± 1.77 mm, length of Modified Ranawat line 28.66 ± 2.38 mm, length of Redlund-Johnell line 35.11 ± 4.09 mm, clivus canal angle 157.62° ± 11.85°, Welcher basal angle 130.83° ± 6.29°, craniocervical tilt 126.98° ± 12.24° and Powers ratio as 0.72 ± 0.06.

CONCLUSION

In this study, the morphometric values were evaluated according to age and gender in individuals who did not have any radiologic anomalies. The normal reference ranges may be useful for researchers who are researching pathology in this region. It is recommended to conduct further studies with different populations to determine the normal reference range.

Cervicomedullary angle as an independent radiological predictor of postoperative neurological outcome in type A basilar invagination

To propose an independent radiological index to evaluate surgical outcomes of A type basilar invagination, a retrospective study was conducted to compare the clinical outcome between procedures 1 and 2 by applying intraoperative consistent traction and manual reduction. Moreover, the atlantodental interval (ADI), cervicomedullary angle (CMA), bilateral sagittal inclination of atlantoaxial joint (SIAA) were measured and compared to pre-operation. Postoperatively, only these patients undergoing procedure 2 achieved significant neurological improvement. The ADIs and the SIAAs decreased in both groups, these differences are statistically significant between pre- and post- operation. For postoperative CMAs, only these patients undergoing modified surgery gained significant improvement of angle with mean 141°. We concluded that the CMA or SIAA could be a radiological predictor to evaluate surgical outcome in BI, among which the CMA is a more independent and easily measurable predictor that is closely correlated with satisfactory neurological improvements. Moreover, procedure 2 with intraoperative resistant cranial traction and manual reduction can help us achieve a good CMA.

C1-C2 pedicle screw fixation for adolescent with os odontoideum associated atlantoaxial dislocation and a compound reduction technique for irreducible atlantoaxial dislocation

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Usefulness of 3D Printed Models in the Management of Complex Craniovertebral Junction Anomalies: Choice of Treatment Strategy, Design of Screw Trajectory, and Protection of Vertebral Artery

OBJECTIVE

To evaluate the usefulness of 3-dimensional (3D) printed models as an aid for the treatment of complex CVJ anomalies.

METHODS

3D printed models were fabricated for 21 patients with complex CVJ anomalies, including vertebral artery anomaly, thin C2 pedicle, vertical atlantoaxial facet joint, or rotational dislocation combined with atlantoaxial dislocation and basilar invagination. Preoperative planning, surgical simulation, and intraoperative reference were achieved using the 3D model during the surgical treatment. The usefulness of 3D printed models, and postoperative clinical and radiological outcomes were assessed.

RESULTS

Direct posterior reduction and atlantoaxial fixation were achieved in 19 patients. Transoral odontoidectomy followed by posterior fixation was implemented for 2 patients with vertical facet joint and rotational dislocation. All screws were safely inserted with no complication, and 90% patients achieved a >60% reduction of both horizontal and vertical dislocation. Clinical symptoms improved in all patients, with the averaged Japanese Orthopedic Association scores increasing from 11.14 to 14.43 (P < 0.01).

CONCLUSIONS

The patient-specific 3D printed model would be an effective tool for evaluation of the reducibility of the atlantoaxial dislocation and basilar invagination, decision making in choosing the optimal surgical approach and way of fixation, and precise placement of the screw while protecting the vertebral artery and spinal cord. The risk of neurovascular injury was minimized, and encouraging outcomes were achieved with the aid of this technique.

Vertico-horizontal atlantoaxial index (VHAI): A new craniovertebral radiographic index

OBJECTIVE

The purpose of this study was to develop a new index that can reliably quantify the reduction of basilar invagination with atlantoaxial dislocation.

PATIENTS AND METHODS

Between May 2012 and September 2017, 40 patients with congenital basilar invagination and atlantoaxial dislocation as well as 100 sex-and age-matched control subjects were recruited for this study. All patients underwent direct posterior reduction and fixation. Mid-sagittal computerized tomography scan films were obtained before and after surgery as well as the vertico-horizontal atlantoaxial index (VHAI) was measured in all patients -before and after surgery- and controls. Additionally, the pre-and postoperative Japanese Orthopedic Association (JOA) scores, Nurick grading, European Myelopathy Score (EMS) and Prolo Scale score were used to evaluate the cervical myelopathy.

RESULTS

The mean follow-up was 24.75 months with a range of 6-60 months. The mean value of VHAI in the control group was 87.86 ± 24.98 mm², while the mean values of VHAI before and after surgery were 209.45 ± 96.80 mm² and 95.08 ± 66.95 mm², respectively. Additionally, in the patient group, a negative correlation was observed between JOA, EMS, Prolo Scale scores and VHAI. On the other hand, a positive correlation was found between the Nurick grading and VHAI.

CONCLUSION

The VHAI can be an excellent measurement tool to evaluate the reduction of basilar invagination with atlantoaxial dislocation. There was a negative correlation between VHAI and JOA, EMS and Prolo Scale scores, and a positive correlation with Nurick grading; which indicates the effectiveness of this index.

Full-endoscopic uniportal retropharyngeal odontoidectomy for anterior craniocervical infection

BACKGROUND

Infections of the anterior craniocervical junction may require surgery. There are various techniques with individual advantages and disadvantages. This study evaluates the full-endoscopic uniportal technique via the anterior retropharyngeal approach for odontoidectomy, decompression, and debridement.

MATERIAL AND METHODS

Three patients with an infection of the anterior craniocervical junction with retrodental involvement were operated on between 2014 and 2016 using the full-endoscopic uniportal technique. Posterior stabilization was also performed with the same procedure for all patients.

RESULTS

The operation was technically satisfactory in all cases. No problems due to swelling of the pharyngeal soft tissue occurred. No other complications were observed. All patients had a satisfactory outcome with stable regression of the myelopathy symptoms and/or complete healing of the infection. The follow-up images showed sufficient decompression of bone and soft tissues in all cases.

CONCLUSIONS

The full-endoscopic uniportal technique with an anterior retropharyngeal approach can be an adequate and minimally invasive surgical technique for odontoidectomy, decompression, and debridement in infections of the craniocervical junction and can reduce access-related problems. The transoral, transnasal, and retropharyngeal approaches have different surgical fields due to the access trajectories, which must be taken into consideration depending on the anatomy and pathology when selecting a suitable technique.

Full-endoscopic Uniportal Odontoidectomy and Decompression of the Anterior Cervicomedullary Junction Using the Retropharyngeal Approach

STUDY DESIGN

A study of a series of consecutive full-endoscopic uniportal decompressions of the anterior craniocervical junction with retropharyngeal approach.

OBJECTIVE

The aim of this study was to evaluate the direct anterior decompression of the craniocervical junction in patients with bulbomedullary compression using a full-endoscopic uniportal technique via an anterolateral retropharyngeal approach.

SUMMARY OF BACKGROUND DATA

Acute or progressive myelopathy may necessitate direct anterior decompression of the craniocervical junction and odontoidectomy. Different techniques with individual advantages and disadvantages can be used. In addition to the gold standard - the transoral approach - there is increasing experience with the endoscopic transnasal technique. Other alternative procedures are also being developed.

METHODS

Between 2013 and 2016, eight patients with basilar impression, retrodental pannus, or retrodental infection were operated in the full-endoscopic uniportal technique with a retropharyngeal approach. Anterior decompression of the bulbomedullary junction with odontoidectomy was performed. All patients additionally underwent posterior stabilization. Imaging and clinical data were collected in follow-up examinations for 1 year.

RESULTS

The bulbomedullary junction was adequately decompressed. No problems due to swelling of pharyngeal soft tissue occurred. One patient required revision due to secondary bleeding. No other complications were observed. All patients had a good clinical outcome with stable regression of the myelopathy symptoms and/or healing of the infection. The imaging follow-up showed sufficient decompression of bone and soft tissue in all cases. No evidence was found of increasing instability or failure of posterior fusion.

CONCLUSION

In the operated patients, the full-endoscopic uniportal surgical technique with anterior retropharyngeal approach was found to be a sufficient and minimally invasive method with the known advantages of an endoscopic procedure under continuous irrigation. It should not be viewed only as competition for other surgical techniques - due to its individual technical parameters, it can also be considered to be an alternative or complementary procedure.

LEVEL OF EVIDENCE

4.

Clinical significance of changes in pB-C2 distance in patients with Chiari Type I malformations following posterior fossa decompression: a single-institution experience

OBJECT The coexistence of Chiari malformation Type I (CM-I) and ventral brainstem compression (VBSC) has been well documented, but the change in VBSC after posterior fossa decompression (PFD) has undergone little investigation. In this study the authors evaluated VBSC in patients with CM-I and determined the change in VBSC after PFD, correlating changes in VBSC with clinical status and the need for further intervention. METHODS Patients who underwent PFD for CM-I by the senior author from November 2005 to January 2013 with complete radiological records were included in the analysis. The following data were obtained: objective measure of VBSC (pB-C2 distance); relationship of odontoid to Chamberlain's, McGregor's, McRae's, and Wackenheim's lines; clival length; foramen magnum diameter; and basal angle. Statistical analyses were performed using paired t-tests and a mixed-effects ANOVA model. RESULTS Thirty-one patients were included in the analysis. The mean age of the cohort was 10.0 years. There was a small but statistically significant increase in pB-C2 postoperatively (0.5 mm, p < 0.0001, mixed-effects ANOVA). Eleven patients had postoperative pB-C2 values greater than 9 mm. The mean distance from the odontoid tip to Wackenheim's line did not change after PFD, signifying postoperative occipitocervical stability. No patients underwent transoral odontoidectomy or occipitocervical fusion. No patients experienced clinical deterioration after PFD. CONCLUSIONS The increase in pB-C2 in patients undergoing PFD may occur as a result of releasing the posterior vector on the ventral dura, allowing it to relax posteriorly. This increase appears to be well-tolerated, and a postoperative pB-C2 measurement of more than 9 mm in light of stable craniocervical metrics and a nonworsened clinical examination does not warrant further intervention.

The importance of craniovertebral and cervicomedullary angles in cervicogenic headache

PURPOSE

Many studies have indicated that cervicogenic headache may originate from the cervical structures innervated by the upper cervical spinal nerves. To date, no study has investigated whether narrowing of the craniovertebral angle (CVA) or cervicomedullary angle (CMA) affects the three upper cervical spinal nerves. The aim of this study was to investigate the effect of CVA and/or CMA narrowing on the occurrence of cervicogenic headache.

MATERIALS AND METHODS

Two hundred and five patients diagnosed with cervicogenic headache were included in the study. The pain scores of patients were determined using a visual analog scale. The nonheadache control group consisted of 40 volunteers. CVA and CMA values were measured on sagittal T2-weighted magnetic resonance imaging (MRI), on two occasions by two radiologists. Angle values and categorized pain scores were compared statistically between the groups.

RESULTS

Intraobserver and interobserver agreement was over 97% for all measurements. Pain scores increased with decreasing CVA and CMA values. Mean angle values were significantly different among the pain categories (P < 0.001). The pain score was negatively correlated with CMA (Spearman correlation coefficient, rs, -0.676; P < 0.001) and CVA values (rs, -0.725; P < 0.001).

CONCLUSION

CVA or CMA narrowing affects the occurrence of cervicogenic headache. There is an inverse relationship between the angle values and pain scores.

Anterior transoral atlantoaxial release and posterior instrumented fusion for irreducible congenital basilar invagination

PURPOSE

Recently, it has been demonstrated that anterior release of tight structures via a transoral approach can assist posterior distraction-reduction technique in restoring the cranio-cervical anatomy in irreducible atlantoaxial dislocations. Our aim was to evaluate the radiological and clinical outcome of anterior release and posterior instrumentation for irreducible congenital basilar invagination.

METHODS

A consecutive series of 15 patients (2007-2009) with irreducible congenital basilar invagination were treated with anterior release using transoral approach. A retrospective chart review was performed. All patients presented with myelopathy. Dislocation was treated as irreducible if acceptable reduction was not achieved with traction under general anesthesia and neuromuscular paralysis. The anterior release comprised of transverse sectioning the longus colli and capitis, C1-C2 joint capsular release and intra-articular adhesiolysis with or without anterior C1 arch excision. Cantilever mechanism using posterior instrumentation was used to correct any residual malalignment.

RESULTS

Mean age was 21.4 (10-50) years. Average duration of follow-up was 28 (24-40) months. The average preoperative JOA score was 11.4 (8-16), which improved to 15.4 (10-18) after surgery. Anatomical reduction was achieved in thirteen patients. Fusion was documented in all patients. Complications included persistent nasal phonation in one, and superficial wound dehiscence in one.

CONCLUSION

We believe that a significant number of irreducible dislocations can be anatomically reduced with this procedure thus avoiding odontoid excision. Encouraging results from this short series have given us a new perspective in dealing with these challenging problems.

Pontine encephalocele and abnormalities of the posterior fossa following transclival endoscopic endonasal surgery

OBJECT

Transclival endoscopic endonasal surgery (EES) has recently been used for the treatment of posterior fossa tumors. The optimal method of reconstruction of large clival defects following EES has not been established.

METHODS

A morphometric analysis of the posterior fossa was performed in patients who underwent transclival EES to compare those with observed postoperative anatomical changes (study group) to 50 normal individuals (anatomical control group) and 41 matched transclival cases with preserved posterior fossa anatomy (case-control group) using the same parameters. Given the absence of clival bone following transclival EES, the authors used the line between the anterior commissure and the basion as an equivalent to the clival plane to evaluate the location of the pons. Four parameters were studied and compared in the two populations: the pontine location/displacement, the maximum anteroposterior (AP) diameter of the pons, the maximum AP diameter of the fourth ventricle, and the cervicomedullary angle (CMA). All measurements were performed on midsagittal 3-month postoperative MR images in the study group.

RESULTS

Among 103 posterior fossa tumors treated with transclival EES, 14 cases (13.6%) with postoperative posterior fossa anatomy changes were identified. The most significant change was anterior displacement of the pons (transclival pontine encephalocele) compared with the normal location in the anatomical control group (p < 0.0001). Other significant deformities were expansion of the AP diameter of the pons (p = 0.005), enlargement of the fourth ventricle (p = 0.001), and decrease in the CMA (p < 0.0001). All patients who developed these changes had undergone extensive resection of the clival bone (> 50% of the clivus) and dura. Nine (64.3%) of the 14 patients were overweight (body mass index [BMI] > 25 kg/m(2)). An association between BMI and the degree of pontine encephalocele was observed, but did not reach statistical significance. The use of a fat graft as part of the reconstruction technique following transclival EES with dural opening was the single significant factor that prevented pontine displacement (p = 0.02), associated with 91% lower odds of pontine encephalocele (OR = 0.09, 95% CI 0.01-0.77). The effect of fat graft reconstruction was more pronounced in overweight/obese individuals (p = 0.04) than in normal-weight patients (p = 0.52). Besides reconstruction technique, other noticeable findings were the tendency of younger adults to develop pontine encephalocele (p = 0.05) and the association of postoperative meningitis with the development of posterior fossa deformities (p = 0.05). One patient developed a transient, recurrent subjective diplopia; all others remained asymptomatic.

CONCLUSIONS

Significant changes in posterior fossa anatomy that have potential clinical implications have been observed following transclival transdural EES. These changes are more common in younger patients or those with meningitis and may be associated with BMI. The use of a fat graft combined with the vascularized nasoseptal flap appears to minimize the risk of pontine herniation following transclival EES with dural opening.

Mid-term results of computer-assisted cervical reconstruction for rheumatoid cervical spines

STUDY DESIGN

A retrospective single-center study. We routinely have used C1-C2 transarticular and cervical pedicle screw fixations to reconstruct highly destructed unstable rheumatoid arthritis (RA) cervical lesions. However, there is little data on mid-term results of surgical reconstruction for rheumatoid cervical disorders, particularly, cervical pedicle screw fixation.

OBJECTIVES

The purpose of this study was to evaluate the mid-term surgical results of computer-assisted cervical reconstruction for such lesions.

METHODS

Seventeen subjects (4 men, 13 women; mean age, 61 ± 9 years) with RA cervical lesions who underwent C1-C2 transarticular screw fixation or occipitocervical fixation, with at least 5 years follow-up were studied. A frameless, stereotactic, optoelectronic, CT-based image-guidance system, was used for correct screw placement. Variables including the Japanese Orthopaedic Association (JOA) score, Ranawat class, EuroQol (EQ-5D), atlantodental interval, and Ranawat values before, and at 2 and 5 years after surgery, were evaluated. Furthermore, screw perforation rates were evaluated.

RESULTS

The lesions included atlantoaxial subluxation (AAS, n = 6), AAS + vertical subluxation (VS, n = 7), and AAS + VS + subaxial subluxation (n = 4). There was significant neurological improvement at 2 years after surgery, as evidenced by the JOA scores, Ranawat class, and the EQ-5D utility weight. However, at 5 years after surgery, there was a deterioration of this improvement. The Ranawat values before, and at 2 and 5 years after surgery, were not significantly different. Major screw perforation rate was 2.1 %. No neural and vascular complications associated with screw insertion were observed.

CONCLUSIONS

Subjects with rheumatoid cervical lesions who underwent C1-C2 transarticular screw fixation or occipitocervical fixation using a pedicle screw had significantly improved clinical parameters at 2 years after surgery. However, there was a deterioration of this improvement at 5 years post surgery.

Posterior occipitocervical fixation under skull-femoral traction for the treatment of basilar impression in a child with Klippel-Feil syndrome

We present the case of a 15-year-old boy with symptoms due to Klippel-Feil syndrome. Radiographs and CT scans demonstrated basilar impression, occipitalisation of C1 and fusion of C2/C3. MRI showed ventral compression of the medullocervical junction. Skull traction was undertaken pre-operatively to determine whether the basilar impression could be safely reduced. During traction, the C3/C4 junction migrated 12 mm caudally and spasticity resolved. Peri-operative skull-femoral traction enabled posterior occipitocervical fixation without decompression. Following surgery, cervical alignment was restored and spasticity remained absent. One year after surgery he was not limited in his activities. The surgical strategy for patients with basilar impression and congenital anomalies remains controversial. The anterior approach with decompression is often recommended for patients with ventral compression of the medullocervical region, but such procedures are technically demanding and carry a significant risk of complications. Our surgical strategy was an alternative solution. Prior to a posterior cervical fixation, without decompression, skull traction was used to confirm that the deformity was reducible and effective in resolving associated myelopathy.