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Han RK, Chae JK, Garton ALA, Cruz A, Navarro-Ramirez R, Hussain I, Härtl R, Greenfield JP. Intraoperative occipital to C2 angle and external acoustic meatus-to-axis angular measurements for optimizing alignment during posterior fossa decompression and occipitocervical fusion for complex Chiari malformation. JOURNAL OF CRANIOVERTEBRAL JUNCTION AND SPINE 2023; 14:365-372. [PMID: 38268687 PMCID: PMC10805164 DOI: 10.4103/jcvjs.jcvjs_59_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/21/2023] [Indexed: 01/26/2024] Open
Abstract
Background Excess flexion or extension during occipitocervical fusion (OCF) can lead to postoperative complications, such as dysphagia, respiratory problems, line of sight issues, and neck pain, but posterior fossa decompression (PFD) and OCF require different positions that require intraoperative manipulation. Objective The objective of this study was to describe quantitative fluoroscopic morphometrics in Chiari malformation (CM) patients with symptoms of craniocervical instability (CCI) and demonstrate the intraoperative application of these measurements to achieve neutral craniocervical alignment while leveraging a single axis of motion with the Mayfield head clamp locking mechanism. Methods A retrospective cohort study of patients with CM 1 and 1.5 and features of CCI who underwent PFD and OCF at a single-center institution from March 2015 to October 2020 was performed. Patient demographics, preoperative presentation, radiographic morphometrics, operative details, complications, and clinical outcomes were analyzed. Results A total of 39 patients met the inclusion criteria, of which 37 patients (94.9%) did not require additional revision surgery after PFD and OCF. In this nonrevision cohort, preoperative to postoperative occipital to C2 angle (O-C2a) (13.5° ± 10.4° vs. 17.5° ± 10.1°, P = 0.047) and narrowest oropharyngeal airway space (nPAS) (10.9 ± 3.4 mm vs. 13.1 ± 4.8 mm, P = 0.007) increased significantly. These measurements were decreased in the two patients who required revision surgery due to postoperative dysphagia (mean difference - 16.6°° in O C2a and 12.8°° in occipital and external acoustic meatus to axis angle). Based on these results, these fluoroscopic morphometrics are intraoperatively assessed, utilizing a locking Mayfield head clamp repositioning maneuver to optimize craniocervical alignment prior to rod placement from the occipital plate to cervical screws. Conclusion Establishing a preoperative baseline of reliable fluoroscopic morphometrics can guide surgeons intraoperatively in appropriate patient realignment during combined PFD and OCF, and may prevent postoperative complications.
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Affiliation(s)
- Rachael K. Han
- Department of Neurological Surgery, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY, USA
| | - John K. Chae
- Department of Neurological Surgery, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY, USA
| | - Andrew L. A. Garton
- Department of Neurological Surgery, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY, USA
| | - Amanda Cruz
- Department of Neurological Surgery, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY, USA
| | - Rodrigo Navarro-Ramirez
- Department of Neurological Surgery, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY, USA
- Department of Neurological Surgery, Weill Cornell Medicine, New York Presbyterian-Och Spine, New York, NY, USA
| | - Ibrahim Hussain
- Department of Neurological Surgery, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY, USA
- Department of Neurological Surgery, Weill Cornell Medicine, New York Presbyterian-Och Spine, New York, NY, USA
| | - Roger Härtl
- Department of Neurological Surgery, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY, USA
- Department of Neurological Surgery, Weill Cornell Medicine, New York Presbyterian-Och Spine, New York, NY, USA
| | - Jeffrey P. Greenfield
- Department of Neurological Surgery, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY, USA
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Dastagirzada YM, Kurland DB, Hankinson TC, Anderson RCE. Craniovertebral Junction Instability in the Setting of Chiari Malformation. Neurosurg Clin N Am 2023; 34:131-142. [DOI: 10.1016/j.nec.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Wang S, Zhang D, Wu K, Fan W, Fan T. Potential association among posterior fossa bony volume and crowdedness, tonsillar hernia, syringomyelia, and CSF dynamics at the craniocervical junction in Chiari malformation type I. Front Neurol 2023; 14:1069861. [PMID: 36891476 PMCID: PMC9986261 DOI: 10.3389/fneur.2023.1069861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/26/2023] [Indexed: 02/22/2023] Open
Abstract
Objective The characteristic morphological parameters (bony posterior fossa volume (bony-PFV), posterior fossa crowdness, cerebellar tonsillar hernia, and syringomyelia) and CSF dynamics parameters at the craniocervical junction (CVJ) in Chiari malformation type I (CMI) were measured. The potential association between these characteristic morphologies and CSF dynamics at CVJ was analyzed. Methods A total of 46 cases of control subjects and 48 patients with CMI underwent computed tomography and phase-contrast magnetic resonance imaging. Seven morphovolumetric measures and four CSF dynamics at CVJ measures were performed. The CMI cohort was further divided into "syringomyelia" and "non-syringomyelia" subgroups. All the measured parameters were analyzed by the Pearson correlation. Results Compared with the control, the posterior cranial fossa (PCF) area, bony-PFV, and CSF net flow were significantly smaller (P < 0.001) in the CMI group. Otherwise, the PCF crowdedness index (PCF CI, P < 0.001) and the peak velocity of CSF (P < 0.05) were significantly larger in the CMI cohort. The mean velocity (MV) was faster in patients with CMI with syringomyelia (P < 0.05). In the correlation analysis, the degree of cerebellar tonsillar hernia was correlated with PCF CI (R = 0.319, P < 0.05), MV (R = -0.303, P < 0.05), and the net flow of CSF (R = -0.300, P < 0.05). The Vaquero index was well correlated with the bony-PFV (R= -0.384, P < 0.05), MV (R = 0.326, P < 0.05), and the net flow of CSF (R = 0.505, P < 0.05). Conclusion The bony-PFV in patients with CMI was smaller, and the MV was faster in CMI with syringomyelia. Cerebellar subtonsillar hernia and syringomyelia are independent indicators for evaluating CMI. Subcerebellar tonsillar hernia was associated with PCF crowdedness, MV, and the net flow of CSF at CVJ, while syringomyelia was associated with bony-PFV, MV, and the net flow of CSF at the CVJ. Thus, the bony-PFV, PCF crowdedness, and the degree of CSF patency should also be one of the indicators of CMI evaluation.
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Affiliation(s)
- Shengxi Wang
- Department of Spinal Spine Surgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Dongao Zhang
- Department of Spinal Spine Surgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Kun Wu
- Department of Spinal Spine Surgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Wayne Fan
- Faculty of Science, University of British Columbia, Vancouver, BC, Canada
| | - Tao Fan
- Department of Spinal Spine Surgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
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Chae JK, Marianayagam NJ, Hussain I, Cruz A, Baaj AA, Härtl R, Greenfield JP. Predicting clinical outcomes using morphometric changes in adults with complex Chiari malformation undergoing occipitocervical fusion with or without ventral decompression: patient series. JOURNAL OF NEUROSURGERY: CASE LESSONS 2021; 2:CASE21364. [PMID: 36059719 PMCID: PMC9435543 DOI: 10.3171/case21364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 07/06/2021] [Indexed: 11/21/2022]
Abstract
BACKGROUND The authors assessed the connection between clinical outcomes and morphometrics in patients with complex Chiari malformation (CM) who have undergone posterior fossa decompression (PFD) and subsequent occipitocervical fusion (OCF) with or without ventral decompression (VD). OBSERVATIONS The authors retrospectively reviewed 33 patients with CM aged over 21 years who underwent PFD and OCF with or without endoscopic endonasal odontoidectomy at the authors’ institution (21 OCF only and 12 OCF + VD). Clivoaxial angle (CXA), pB-C2 (perpendicular line to the line between the basion and C2), atlantodental interval (ADI), basion-dens interval (BDI), basion-axial interval (BAI), and C1 canal diameter were measured on preoperative and approximately 3-month postoperative computed tomography or magnetic resonance imaging scans. Common symptoms included headache, paresthesia, and bulbar symptoms. Clinical improvement after surgery was observed in 78.8% of patients. CXA, ADI, and BDI all significantly increased after surgery, whereas pB-C2 and BAI significantly decreased. OCF + VD had a significantly more acute CXA and longer pB-C2 preoperatively than OCF only. Patients who clinically improved postoperatively showed the same significant morphometric changes, but those who did not improve showed no significant morphometric changes. LESSONS Patients showing improvement had greater corrections in skull base morphometrics than those who did not. Although there are various mutually nonexclusive reasons why certain patients do not improve after surgery, smaller degrees of morphometric correction could play a role.
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Affiliation(s)
- John K. Chae
- Department of Neurological Surgery, Weill Cornell Medicine/NewYork-Presbyterian Hospital, New York, New York; and
| | - Neelan J. Marianayagam
- Department of Neurological Surgery, Weill Cornell Medicine/NewYork-Presbyterian Hospital, New York, New York; and
| | - Ibrahim Hussain
- Department of Neurological Surgery, Weill Cornell Medicine/NewYork-Presbyterian Hospital, New York, New York; and
| | - Amanda Cruz
- Department of Neurological Surgery, Weill Cornell Medicine/NewYork-Presbyterian Hospital, New York, New York; and
| | - Ali A. Baaj
- Department of Neurosurgery, University of Arizona College of Medicine, Phoenix, Arizona
| | - Roger Härtl
- Department of Neurological Surgery, Weill Cornell Medicine/NewYork-Presbyterian Hospital, New York, New York; and
| | - Jeffrey P. Greenfield
- Department of Neurological Surgery, Weill Cornell Medicine/NewYork-Presbyterian Hospital, New York, New York; and
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Sunshine KS, Elder TA, Tomei KL. Noninvasive evaluation of craniovertebral junction instability in 2 patients following Chiari decompression with rigid C-collar immobilization: illustrative cases. JOURNAL OF NEUROSURGERY: CASE LESSONS 2021; 1:CASE20114. [PMID: 36045931 PMCID: PMC9394172 DOI: 10.3171/case20114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 12/09/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND The complex Chiari malformation has been identified in a subset of Chiari patients at higher risk for worsening symptoms following Chiari decompression. Although parameters such as the clivoaxial angle and the perpendicular distance of the dens to the line from the basion to the inferoposterior part of the C2 body (pBC2) have been evaluated to help with the prediction of risk, the decision to pursue an occipitocervical fusion in lower-risk patients does not come without inherent risk. OBSERVATIONS The authors present 2 patients who had symptoms of worsening ventral brainstem compression following Chiari decompression, neither of whom was categorized in the highest risk category for occipitocervical instability. In addition, neither patient had gross instability on radiographic imaging. A trial with rigid C-collar immobilization provided relief of symptoms in both patients and allowed reassurance of the likelihood of success of occipitocervical fusion. LESSONS In patients without clear radiographic instability following Chiari decompression, a C-collar trial may provide a noninvasive option for assessing the potential success of occipitocervical fusion.
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Affiliation(s)
| | - Theresa A. Elder
- Department of Neurological Surgery, University Hospitals Cleveland Medical Center, Cleveland, Ohio
- Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Krystal L. Tomei
- Department of Neurological Surgery, University Hospitals Cleveland Medical Center, Cleveland, Ohio
- Case Western Reserve University School of Medicine, Cleveland, Ohio
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den Ottelander BK, de Goederen R, de Planque CA, Baart SJ, van Veelen MLC, Corel LJA, Joosten KFM, Mathijssen IMJ, Dremmen MHG. Cervical Spinal Cord Compression and Sleep-Disordered Breathing in Syndromic Craniosynostosis. AJNR Am J Neuroradiol 2020; 42:201-205. [PMID: 33272949 DOI: 10.3174/ajnr.a6881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/19/2020] [Indexed: 11/07/2022]
Abstract
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.
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Affiliation(s)
- B K den Ottelander
- From the Dutch Craniofacial Center (B.K.d.O., R.D.G., C.A.d.P., I.M.J.M.), Department of Plastic and Reconstructive Surgery and Hand Surgery
| | - R de Goederen
- From the Dutch Craniofacial Center (B.K.d.O., R.D.G., C.A.d.P., I.M.J.M.), Department of Plastic and Reconstructive Surgery and Hand Surgery
| | - C A de Planque
- From the Dutch Craniofacial Center (B.K.d.O., R.D.G., C.A.d.P., I.M.J.M.), Department of Plastic and Reconstructive Surgery and Hand Surgery
| | - S J Baart
- Department of Biostatistics (S.J.B.), Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | | | - L J A Corel
- Pediatric Intensive Care Unit (L.J.A.C., K.F.M.J.)
| | | | - I M J Mathijssen
- From the Dutch Craniofacial Center (B.K.d.O., R.D.G., C.A.d.P., I.M.J.M.), Department of Plastic and Reconstructive Surgery and Hand Surgery
| | - M H G Dremmen
- Department of Radiology (M.H.G.D.), Erasmus MC Sophia Children's Hospital, University Medical Center Rotterdam, Rotterdam, Rotterdam, the Netherlands
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Bapuraj JR, Bruzek AK, Tarpeh JK, Pelissier L, Garton HJL, Anderson RCE, Nan B, Ma T, Maher CO. Morphometric changes at the craniocervical junction during childhood. J Neurosurg Pediatr 2019; 24:227-235. [PMID: 31226679 DOI: 10.3171/2019.4.peds1968] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/30/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Current understanding of how the pediatric craniocervical junction develops remains incomplete. Measurements of anatomical relationships at the craniocervical junction can influence clinical and surgical decision-making. The purpose of this analysis was to quantitatively define clinically relevant craniocervical junction measurements in a population of children with CT scans that show normal anatomy. METHODS A total of 1458 eligible patients were identified from children between 1 and 18 years of age who underwent cervical spine CT scanning at a single institution. Patients were separated by both sex and age in years into 34 groups. Following this, patients within each group were randomly selected for inclusion until a target of 15 patients in each group had been reached. Each patient underwent measurement of the occipital condyle-C1 interval (CCI), pB-C2, atlantodental interval (ADI), basion-dens interval (BDI), basion-opisthion diameter (BOD), basion-axial interval (BAI), dens angulation, and canal diameter at C1. Mean values were calculated in each group. Each measurement was performed by two teams and compared for intraclass correlation coefficient (ICC). RESULTS The data showed that CCI, ADI, BDI, and dens angulation decrease in magnitude throughout childhood, while pB-C2, PADI, BAI, and BOD increase throughout childhood, with an ICC of fair to good (range 0.413-0.912). Notably, CCI decreases continuously on coronal CT scans, whereas on parasagittal CT scans, CCI does not decrease until after age 9, when it shows a continuous decline similar to measurements on coronal CT scans. CONCLUSIONS These morphometric analyses establish parameters for normal pediatric craniocervical spine growth for each year of life up to 18 years. The data should be considered when evaluating children for potential surgical intervention.
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Affiliation(s)
| | - Amy K Bruzek
- 2Neurosurgery, University of Michigan, Ann Arbor, Michigan
| | | | | | | | - Richard C E Anderson
- 3Department of Neurosurgery, Columbia University College of Physicians and Surgeons, New York, New York
| | - Bin Nan
- 4Department of Statistics, University of California, Irvine, California; and
| | - Tianwen Ma
- 5Department of Biostatistics, University of Michigan, Ann Arbor, Michigan
| | - Cormac O Maher
- 2Neurosurgery, University of Michigan, Ann Arbor, Michigan
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Abstract
As with many pathologies, the course of our understanding of the Chiari I malformation (CIM) has developed extensively over time. The early descriptions of the Chiari malformations by Hans Chiari in 1891 opened the door for future classification and research on this topic. However, even over a long timeframe, our understanding of the pathophysiology and, more importantly, treatment, remained in its infancy. As recently as the 1970s, CIM was not discussed in popular neurology textbooks. Syringomyelia is listed as a degenerative disorder with no satisfactory treatment. Radiation therapy was considered an option in treatment, and surgery was thought to play no role. During the last 40 years, equivalent to the duration of a neurosurgical career, our understanding of the pathophysiology and natural history of CIM, coupled with modern MRI, has improved the treatment paradigm for this patient population. More importantly, it has given us evidence confirming that CIM is a disorder responsive to surgical intervention, giving patients once thought to be destined for lifelong disability a comparatively normal life after treatment. The purpose of this article is to offer a review of CIM and its important associated entities. The authors will discuss the evolution in understanding of the Chiari malformation and, importantly, distinguish between symptomatic CIM and asymptomatic tonsillar ectopia, based on imaging and presenting symptomatology. They will discuss techniques for surgical intervention, expected outcomes, and complications after surgery. Proper patient selection for surgery based on appropriate symptomatology is tantamount to achieving good surgical outcomes in this population, separating those who can be helped by surgery from those who are unlikely to improve. While our knowledge of the Chiari malformations continues to improve through the efforts of clinical and basic science researchers, surgeons, and patients, our current understanding of these entities represents a monumental improvement in patient care over a relatively short time period.
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Hankinson TC, Tuite GF, Moscoso DI, Robinson LC, Torner JC, Limbrick DD, Park TS, Anderson RCE. Analysis and interrater reliability of pB-C2 using MRI and CT: data from the Park-Reeves Syringomyelia Research Consortium on behalf of the Pediatric Craniocervical Society. J Neurosurg Pediatr 2017; 20:170-175. [PMID: 28524792 DOI: 10.3171/2017.3.peds16604] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The distance to the ventral dura, perpendicular to the basion to C2 line (pB-C2), is commonly employed as a measure describing the anatomy of the craniovertebral junction. However, both the reliability among observers and the clinical utility of this measurement in the context of Chiari malformation Type I (CM-I) have been incompletely determined. METHODS Data were reviewed from the first 600 patients enrolled in the Park-Reeves Syringomyelia Research Consortium with CM-I and syringomyelia. Thirty-one cases were identified in which both CT and MRI studies were available for review. Three pediatric neurosurgeons independently determined pB-C2 values using common imaging sequences: MRI (T1-weighted and T2-weighted with and without the inclusion of retro-odontoid soft tissue) and CT. Values were compared and intraclass correlations were calculated among imaging modalities and observers. RESULTS Intraclass correlation of pB-C2 demonstrated strong agreement between observers (intraclass correlation coefficient [ICC] range 0.72-0.76). Measurement using T2-weighted MRI with the inclusion of retro-odontoid soft tissue showed no significant difference with measurement using T1-weighted MRI. Measurements using CT or T2-weighted MRI without retro-odontoid soft tissue differed by 1.6 mm (4.69 and 3.09 mm, respectively, p < 0.05) and were significantly shorter than those using the other 2 sequences. Conclusions pB-C2 can be measured reliably by multiple observers in the context of pediatric CM-I with syringomeyelia. Measurement using T2-weighted MRI excluding retro-odontoid soft tissue closely approximates the value obtained using CT, which may allow for the less frequent use of CT in this patient population. Measurement using T2-weighted MRI including retro-odontoid soft tissue or using T1-weighted MRI yields a more complete assessment of the extent of ventral brainstem compression, but its association with clinical outcomes requires further study.
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Affiliation(s)
- Todd C Hankinson
- Pediatric Neurosurgery, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, and.,Department of Neurosurgery, University of Colorado School of Medicine, Aurora, Colorado
| | - Gerald F Tuite
- Division of Pediatric Neurosurgery, Neuroscience Institute, Johns Hopkins All Children's Hospital, St. Petersburg, Florida
| | - Dagmara I Moscoso
- Department of Neurosurgery, Columbia University, Morgan Stanley Children's Hospital of NewYork-Presbyterian, New York, New York
| | - Leslie C Robinson
- Department of Neurosurgery, University of Colorado School of Medicine, Aurora, Colorado
| | - James C Torner
- University of Iowa College of Public Health, Iowa City, Iowa; and
| | - David D Limbrick
- Department of Neurological Surgery, Washington University School of Medicine, Saint Louis, Missouri
| | - Tae Sung Park
- Department of Neurological Surgery, Washington University School of Medicine, Saint Louis, Missouri
| | - Richard C E Anderson
- Department of Neurosurgery, Columbia University, Morgan Stanley Children's Hospital of NewYork-Presbyterian, New York, New York
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Utility of the clivo-axial angle in assessing brainstem deformity: pilot study and literature review. Neurosurg Rev 2017; 41:149-163. [PMID: 28258417 PMCID: PMC5748419 DOI: 10.1007/s10143-017-0830-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/30/2017] [Accepted: 02/07/2017] [Indexed: 01/19/2023]
Abstract
There is growing recognition of the kyphotic clivo-axial angle (CXA) as an index of risk of brainstem deformity and craniocervical instability. This review of literature and prospective pilot study is the first to address the potential correlation between correction of the pathological CXA and postoperative clinical outcome. The CXA is a useful sentinel to alert the radiologist and surgeon to the possibility of brainstem deformity or instability. Ten adult subjects with ventral brainstem compression, radiographically manifest as a kyphotic CXA, underwent correction of deformity (normalization of the CXA) prior to fusion and occipito-cervical stabilization. The subjects were assessed preoperatively and at one, three, six, and twelve months after surgery, using established clinical metrics: the visual analog pain scale (VAS), American Spinal InjuryAssociation Impairment Scale (ASIA), Oswestry Neck Disability Index, SF 36, and Karnofsky Index. Parametric and non-parametric statistical tests were performed to correlate clinical outcome with CXA. No major complications were observed. Two patients showed pedicle screws adjacent to but not deforming the vertebral artery on post-operative CT scan. All clinical metrics showed statistically significant improvement. Mean CXA was normalized from 135.8° to 163.7°. Correction of abnormal CXA correlated with statistically significant clinical improvement in this cohort of patients. The study supports the thesis that the CXA maybe an important metric for predicting the risk of brainstem and upper spinal cord deformation. Further study is feasible and warranted.
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