- Email: [email protected]
Chiari Malformation and Syringomyelia Associated with Hirayama Disease
Journal Pre-proof Chiari formation, syringomyelia associated with Hirayama disease Atul Goel, M.Ch, Neurosurgery, Neha Jadhav, Abhidha Shah, M.Ch., Neurosurgery, Survendra Rai, M.Ch., Neurosurgery, Ravikiran Vutha, M.Ch., Neurosurgery PII:
S1878-8750(19)33133-X
DOI:
https://doi.org/10.1016/j.wneu.2019.12.101
Reference:
WNEU 13948
To appear in:
World Neurosurgery
Received Date: 3 November 2019 Revised Date:
15 December 2019
Accepted Date: 16 December 2019
Please cite this article as: Goel A, Jadhav N, Shah A, Rai S, Vutha R, Chiari formation, syringomyelia associated with Hirayama disease, World Neurosurgery (2020), doi: https://doi.org/10.1016/ j.wneu.2019.12.101. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Inc.
Chiari formation, syringomyelia associated with Hirayama disease
1. Atul Goel M.Ch. Neurosurgery Professor and Head of Department, Department of Neurosurgery, K.E.M Hospital and Seth G.S. Medical College, Parel, Mumbai. and Consultant Neurosurgeon, Lilavati Hospital and Research Centre, Bandra (E), Mumbai. 2. Neha Jadhav Senior Resident, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai. 3. Abhidha Shah M.Ch. Neurosurgery Assistant Professor, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai 4. Survendra Rai M.Ch. Neurosurgery Assistant Professor, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai. 5. Ravikiran Vutha M.Ch. Neurosurgery Senior Resident, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai.
Correspondence: Prof. Atul Goel,
Head of Department, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai400012, India Telephone no: 22-24129884 Fax no: 22-24143435 E-mail: [email protected]
Conflict of Interest: None Disclosure of Funding: None
Chiari formation, syringomyelia associated with Hirayama disease
1. Atul Goel M.Ch. Neurosurgery Professor and Head of Department, Department of Neurosurgery, K.E.M Hospital and Seth G.S. Medical College, Parel, Mumbai. and Consultant Neurosurgeon, Lilavati Hospital and Research Centre, Bandra (E), Mumbai. 2. Neha JadhavM.Ch. Neurosurgery Senior Resident, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai.
3. Abhidha Shah M.Ch. Neurosurgery Assistant Professor, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai 4. Survendra Rai M.Ch. Neurosurgery Assistant Professor, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai. 5. Ravikiran Vutha M.Ch. Neurosurgery Senior Resident, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai.
Correspondence: Prof. Atul Goel, Head of Department, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai-400012, India
Telephone no: 22-24129884 Fax no: 22-24143435 E-mail: [email protected]
Conflict of Interest: None Disclosure of Funding: None
Chiari formation, syringomyelia associated with Hirayama disease
Abstract: A case of 23-year-old male patient is reported who presented with complaints of pain in the nape of neck and shoulders for 9 months, weakness and stiffness in all 4 limbs and wasting and weakness of muscles of both hands for 6 months. Investigations showed Chiari formation and syringomyelia. Additionally investigations depicted characteristic radiological features that are associated with Hirayama disease. The patient was treated by atlantoaxial and multi-segmental subaxial cervical spinal fixation. The association of Chiari formation and Hirayama disease has never been identified in the literature. The treatment protocol is analyzed.
Key words: atlantoaxial instability, Hirayama disease, Chiari formation, syringomyelia
Introduction: Hirayama disease (monomelic amyotrophy) is a relatively rare neuromuscular syndrome first described in 1959 as “juvenile muscular atrophy of unilateral upper extremity”.1,2 Despite the fact that a number of articles discuss the pathogenesis, clinical and radiological features of Hirayama disease, it may not be incorrect to state that the entire subject is riddled with controversies. The ideal treatment is not yet conclusively identified. Simultaneous presence of Chiari formation associated with syringomyelia and Hirayama disease has never been reported earlier. We have earlier identified atlantoaxial instability as the cause of Chiari formation with or without the association of syringomyelia.3Our earlier report also identified association of atlantoaxial instability and multisegmental spinal instability as the cause of Hirayama disease. The case presents an opportunity to further analyze the pathogenesis and treatment of both Chiari formation and syringomyelia and of Hirayama disease.
Case report: A 23-year-old male presented with the complaints of pain in the neck and progressive stiffness and weakness of all four limbs for 9 months. The weakness was more pronounced in the hands. When admitted, he was able to conduct his routine life activities only with difficulty. Clinical examination revealed spastic quadriparesis, power in the upper limbs being worse. He had wasting of intrinsic muscles of the hands with characteristic (of Hirayama disease) flexion deformity of the lateral two fingers. He was unable to form a firm grip. There was no definite sensory dysfunction. Investigations included dynamic CT and MRI scans. (Figure 1) MRI revealed Chiari formation and syringomyelia from C2 to C7 levels. A well defined enhancing extradural mass, a characteristic radiological feature of Hirayama disease,
was seen extending from C3 to C7 levels on flexion of the neck and disappeared on neck extension. (Figure 1) Lower cervical kyphosis was seen on neck flexion images. Investigations did not reveal any spinal instability when evaluated by validated parameters. As per our previously discussed classification, the atlantoaxial instability was of Type 2, meaning thereby that in neutral head position the facet of atlas was located posterior to the facet of axis. Instability was also observed in the subaxial facetal articulations. Atlantoaxial fixation was done using the technique described by us earlier4,5 and subaxial C3-6 fixation was done using transarticular technique described by Camille and Saillant.6 Essential surgical steps have been described in our earlier reports on the subject of Chiari formation and Hirayama disease. The patient described improvement in all his symptoms in the immediate post-operative period. The clinical recovery progressed over the period. At a follow up of 36 months the patient is back to his routine life. Wasting and deformity of his hands recovered significantly. Post-operative MRI performed after 23 months of surgery showed a marked regression of the extradural enhancing mass. (Figure 2) There was also a regression in the Chiari formation and syringomyelia.
Discussion: Both Chiari formation and Hirayama disease can be associated with disabling weakness and wasting and neuropathic pain. Despite the fact that clinical and radiologic characteristics have been well defined for both these clinical entities, an exact understanding of pathophysiology and treatment strategy remains elusive, or atleast it is highly debated.7-13 Instability of spine that includes atlantoaxial joint as the nodal point of pathogenesis of both Chiari formation and Hirayama disease was first proposed by us.3 In the year 2015, we identified that atlantoaxial instability is the
cause of Chiari formation with or without the association of basilar invagination and syringomyelia.14 Accordingly we proposed atlantoaxial fixation as the treatment. In the year 2017, we proposed that atlantoaxial instability and multisegmental spinal instability is the cause of Hirayama disease and identified atlantoaxial and multisegmental subaxial stabilization as the treatment.3 Our ongoing experience in both these groups of clinical entities confirms our initial observations.15,16
The presented patient had classical neurological symptoms that are generally observed in cases with Chiari formation. In addition, there was focused wasting and weakness of the hands; a feature that is a hallmark of Hirayama disease.The radiological images showed characteristic features of Hirayama disease wherein there is an extradural collection of enhancing mass on flexion of the neck and a typical cervical spinal curvature.
We earlier proposed an alternative classification of atlantoaxial instability that was based on observation of facetal alignments when the patient was placed in neutral head position.17 Type 1 atlantoaxial instability was when the facet of atlas was dislocated anterior to the facet of axis. Type 2 atlantoaxial instability was when the facet of atlas was dislocated posterior to the facet of axis. Type 3 atlantoaxial facetal instability was when the facets of atlas and axis were in alignment and instability was diagnosed during operation by direct observation and manipulation of bones. High degree of clinical suspicion is obviously necessary to suspect and diagnose instability in both Types 2 and 3 atlantoaxial facetal instability. As there may not be any abnormality in the atlantodental interval and there may not be any dural or neural compression by the odontoid process, the instability in the latter two groups is labeled
as central or axial atlantoaxial instability. We have identified central or axial atlantoaxial instability in clinical situations with chronic or longstanding instability like Chiari formation, syringomyelia, cervical spondylosis, OPLL and Hirayama disease.18 In the presented case, there was Type 2 atlantoaxial instability.
In the presented case, atlantoaxial fixation along with multisegmental subaxial spinal fixation was successfully done. The levels of subaxial spinal fixation were essentially identified by the extension of the extradural mass, pattern of cervical kyphosis on neck flexion and by direct assessment of instability by inspection of the facets and manipulation of bones during surgery. The regression of extradural mass and reversal of tonsillar herniation was significant but incomplete. Our experience with Chiari formation suggests that both these features will probably resolve on longer follow-up evaluation.The patient improved in all his clinical symptoms. However, one wonders if atlantoaxial instability is the cause of both Chiari formation and Hirayama disease and if subaxial spinal fixation could have been avoided. Considering that Hirayama disease is by itself a rare clinical problem and association with Chiari formation and syringomyelia has never been identified in the literature, careful diagnosis and identification of cases and further experience with treatment will help clarify the issue.
References: 1. Hirayama K, Toyokura Y, Tsubaki T:Juvenile muscular atrophy of unilateral upper extremity: a new clinical entityPsychiatr Neurol Jpn 1959; 61: 2190–2197
2. Hirayama K: Juvenile muscular atrophy localized in hands and forearm: observation in 38 casesRinsho Shinkkeigaku.1972; 12: 313–324 3. Goel A, Dhar A, Shah A. Multilevel Spinal Stabilization as a Treatment for Hirayama Disease: Report of an Experience with Five Cases. World Neurosurg. 2017;99:186-191. 4. Goel A, Desai K, Muzumdar D: Atlantoaxial fixation using plate and screw method: A report of 160 treated patients. Neurosurgery 2002; 51:1351-1357. 5. Goel A, Laheri VK: Plate and screw fixation for atlanto-axial dislocation. (Technical report). Acta Neurochir (Wien)1994; 129: 47-53. 6. Roy-Camille R, Saillant G. Surgery of the cervical spine. 2. Dislocation. Fracture of the articular processes. Nouv Presse Med1972; 1:2484–5. 7. Hirayama K, Tokumaru Y: Cervical dural sac and spinal cord in juvenile muscular atrophy of distal upper extremityNeurology2000; 54: 1922– 1926 8. Pradhan S: Bilaterally symmetric form of Hirayama disease. Neurology 2009; 72 (24): 2083–2089 9. Nagaoka M. Hirayama K, Chida T, Yokochi M, Narabayashi H: Electromyographic analysis on juvenile muscular atrophy of unilateral upper extremityNo to Shinkei 1980; 32 (8): 821–828 10. Tokumaru Y, Hirayama K Cervical collar therapy for juvenile muscular atrophy of distal upper extremity (Hirayama disease): results from 38 cases. Rinsho Shinkeigaku (Clin Neurol) 2001; 41: 173–178 11. Guo X, Lu M, Xie N, Guo Q, Ni B. Multilevel anterior cervical discectomy and fusion with plate fixation for jeuvenile unilateral
muscular atrophy of the distal upper extremity accompanied by cervical kyphosis. J Spinal Disord Tech. 2014; 27 (7): E241-6. 12. Paredes I, Esteban J, Ramos A, Gonzalez P, Rivas JJ. A severe case of Hirayama disease successfully treated by anterior cervcial fusion. J Neurosurg Spine 2014; 20 (2): 191-5. 13. Ito H, Takai K, Taniguchi M. Cervical duroplasty with tenting sutures via laminoplasty for cervical flexion myelopathy in patients with Hirayama disease: successful decompression of a “tight dural canal in flexion” without spinal fusion. J Neurosurg Spine 2014; 21 (5):743-52. 14. Goel A. Is atlantoaxial instability the cause of Chiari malformation? Outcome analysis of 65 patients treated by atlantoaxial fixation. J Neurosurg Spine. 2015;22(2):116-27. 15. Goel A, Kaswa A, Shah A. Atlantoaxial Fixation for Treatment of Chiari Formation and Syringomyelia with No Craniovertebral Bone Anomaly: Report of an Experience with 57 Cases. Acta Neurochir Suppl. 2019;125:101-110. 16. Shah A, Patil A, Vutha R, Thakar K, Goel A. Recovery of Transcranial Motor Evoked Potentials After Atlantoaxial Stabilization for Chiari Formation: Report of 20 Cases. World Neurosurg. 2019;127:e644-e648. 17. Goel A:Goel’s classification of atlantoaxial “facetal” dislocation. J Craniovertebr Junction Spine2014;5 (1): 3-8. 18. Goel A. A Review of a New Clinical Entity of 'Central Atlantoaxial Instability': Expanding Horizons of Craniovertebral Junction Surgery. Neurospine. 2019;16(2):186-194.
Figure legends: Figure 1: Pre-operative Images Figure 1a: T1-weighted MRI showing Chiari formation and isointense lesion posterior to the subaxial spinal cord. Figure 1b: Contrast enhanced MRI showing the enhancing extradural mass in the posterior aspect of subaxial spinal canal. Figure 1c: T2-weighted MRI showing the mixed intensity lesion in the posterior aspect of subaxial spinal canal. Figure 1d: T2-weighted MRI with the head in extended position showing disappearance of the extradural lesion. Figure 1e: CT scan with the head in flexion showing kyphotic deformity in the subaxial cervical spine. Figure 1f: CT scan with the head in extended position showing normal spinal curvature. Figure 1g: CT scan cut passing through the facets showing posterior dislocation of the facet of atlas over the facet of axis or Type 2 atlantoaxialfacetal instability. Figure 1h: Clinical photograph of the hand showing the deformed fingers.
Figure 2: Post-operative images Figure 2a: Postoperative T1-weighted contrast enhanced MRI showing absence of contrast enhancement posterior to the subaxial spinal cord. Artifact related to implant is seen in the craniovertebral junction region. Figure 2b: Post-operative T2 weighted image showing regression of the extradural mass.
Figure 2c: Postoperative CT scan showing bone graft posterior to the midline bones. Figure 2d: Postoperative CT scan showing the implant in the atlantoaxial and subaxial regions. Figure 2e: Lateral and antero-posterior radiographs showing atlantoaxial fixation by Goel technique and subaxial spinal fixation by Camille’s transarticular fixation technique Figure 2f: Post-operative clinical photograph showing resolution of the deformity.
Abbreviations:
Nil
Conflict of Interest The authors have no conflicts of interest to disclose.
S1878-8750(19)33133-X
DOI:
https://doi.org/10.1016/j.wneu.2019.12.101
Reference:
WNEU 13948
To appear in:
World Neurosurgery
Received Date: 3 November 2019 Revised Date:
15 December 2019
Accepted Date: 16 December 2019
Please cite this article as: Goel A, Jadhav N, Shah A, Rai S, Vutha R, Chiari formation, syringomyelia associated with Hirayama disease, World Neurosurgery (2020), doi: https://doi.org/10.1016/ j.wneu.2019.12.101. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Inc.
Chiari formation, syringomyelia associated with Hirayama disease
1. Atul Goel M.Ch. Neurosurgery Professor and Head of Department, Department of Neurosurgery, K.E.M Hospital and Seth G.S. Medical College, Parel, Mumbai. and Consultant Neurosurgeon, Lilavati Hospital and Research Centre, Bandra (E), Mumbai. 2. Neha Jadhav Senior Resident, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai. 3. Abhidha Shah M.Ch. Neurosurgery Assistant Professor, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai 4. Survendra Rai M.Ch. Neurosurgery Assistant Professor, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai. 5. Ravikiran Vutha M.Ch. Neurosurgery Senior Resident, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai.
Correspondence: Prof. Atul Goel,
Head of Department, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai400012, India Telephone no: 22-24129884 Fax no: 22-24143435 E-mail: [email protected]
Conflict of Interest: None Disclosure of Funding: None
Chiari formation, syringomyelia associated with Hirayama disease
1. Atul Goel M.Ch. Neurosurgery Professor and Head of Department, Department of Neurosurgery, K.E.M Hospital and Seth G.S. Medical College, Parel, Mumbai. and Consultant Neurosurgeon, Lilavati Hospital and Research Centre, Bandra (E), Mumbai. 2. Neha JadhavM.Ch. Neurosurgery Senior Resident, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai.
3. Abhidha Shah M.Ch. Neurosurgery Assistant Professor, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai 4. Survendra Rai M.Ch. Neurosurgery Assistant Professor, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai. 5. Ravikiran Vutha M.Ch. Neurosurgery Senior Resident, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai.
Correspondence: Prof. Atul Goel, Head of Department, Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Parel, Mumbai-400012, India
Telephone no: 22-24129884 Fax no: 22-24143435 E-mail: [email protected]
Conflict of Interest: None Disclosure of Funding: None
Chiari formation, syringomyelia associated with Hirayama disease
Abstract: A case of 23-year-old male patient is reported who presented with complaints of pain in the nape of neck and shoulders for 9 months, weakness and stiffness in all 4 limbs and wasting and weakness of muscles of both hands for 6 months. Investigations showed Chiari formation and syringomyelia. Additionally investigations depicted characteristic radiological features that are associated with Hirayama disease. The patient was treated by atlantoaxial and multi-segmental subaxial cervical spinal fixation. The association of Chiari formation and Hirayama disease has never been identified in the literature. The treatment protocol is analyzed.
Key words: atlantoaxial instability, Hirayama disease, Chiari formation, syringomyelia
Introduction: Hirayama disease (monomelic amyotrophy) is a relatively rare neuromuscular syndrome first described in 1959 as “juvenile muscular atrophy of unilateral upper extremity”.1,2 Despite the fact that a number of articles discuss the pathogenesis, clinical and radiological features of Hirayama disease, it may not be incorrect to state that the entire subject is riddled with controversies. The ideal treatment is not yet conclusively identified. Simultaneous presence of Chiari formation associated with syringomyelia and Hirayama disease has never been reported earlier. We have earlier identified atlantoaxial instability as the cause of Chiari formation with or without the association of syringomyelia.3Our earlier report also identified association of atlantoaxial instability and multisegmental spinal instability as the cause of Hirayama disease. The case presents an opportunity to further analyze the pathogenesis and treatment of both Chiari formation and syringomyelia and of Hirayama disease.
Case report: A 23-year-old male presented with the complaints of pain in the neck and progressive stiffness and weakness of all four limbs for 9 months. The weakness was more pronounced in the hands. When admitted, he was able to conduct his routine life activities only with difficulty. Clinical examination revealed spastic quadriparesis, power in the upper limbs being worse. He had wasting of intrinsic muscles of the hands with characteristic (of Hirayama disease) flexion deformity of the lateral two fingers. He was unable to form a firm grip. There was no definite sensory dysfunction. Investigations included dynamic CT and MRI scans. (Figure 1) MRI revealed Chiari formation and syringomyelia from C2 to C7 levels. A well defined enhancing extradural mass, a characteristic radiological feature of Hirayama disease,
was seen extending from C3 to C7 levels on flexion of the neck and disappeared on neck extension. (Figure 1) Lower cervical kyphosis was seen on neck flexion images. Investigations did not reveal any spinal instability when evaluated by validated parameters. As per our previously discussed classification, the atlantoaxial instability was of Type 2, meaning thereby that in neutral head position the facet of atlas was located posterior to the facet of axis. Instability was also observed in the subaxial facetal articulations. Atlantoaxial fixation was done using the technique described by us earlier4,5 and subaxial C3-6 fixation was done using transarticular technique described by Camille and Saillant.6 Essential surgical steps have been described in our earlier reports on the subject of Chiari formation and Hirayama disease. The patient described improvement in all his symptoms in the immediate post-operative period. The clinical recovery progressed over the period. At a follow up of 36 months the patient is back to his routine life. Wasting and deformity of his hands recovered significantly. Post-operative MRI performed after 23 months of surgery showed a marked regression of the extradural enhancing mass. (Figure 2) There was also a regression in the Chiari formation and syringomyelia.
Discussion: Both Chiari formation and Hirayama disease can be associated with disabling weakness and wasting and neuropathic pain. Despite the fact that clinical and radiologic characteristics have been well defined for both these clinical entities, an exact understanding of pathophysiology and treatment strategy remains elusive, or atleast it is highly debated.7-13 Instability of spine that includes atlantoaxial joint as the nodal point of pathogenesis of both Chiari formation and Hirayama disease was first proposed by us.3 In the year 2015, we identified that atlantoaxial instability is the
cause of Chiari formation with or without the association of basilar invagination and syringomyelia.14 Accordingly we proposed atlantoaxial fixation as the treatment. In the year 2017, we proposed that atlantoaxial instability and multisegmental spinal instability is the cause of Hirayama disease and identified atlantoaxial and multisegmental subaxial stabilization as the treatment.3 Our ongoing experience in both these groups of clinical entities confirms our initial observations.15,16
The presented patient had classical neurological symptoms that are generally observed in cases with Chiari formation. In addition, there was focused wasting and weakness of the hands; a feature that is a hallmark of Hirayama disease.The radiological images showed characteristic features of Hirayama disease wherein there is an extradural collection of enhancing mass on flexion of the neck and a typical cervical spinal curvature.
We earlier proposed an alternative classification of atlantoaxial instability that was based on observation of facetal alignments when the patient was placed in neutral head position.17 Type 1 atlantoaxial instability was when the facet of atlas was dislocated anterior to the facet of axis. Type 2 atlantoaxial instability was when the facet of atlas was dislocated posterior to the facet of axis. Type 3 atlantoaxial facetal instability was when the facets of atlas and axis were in alignment and instability was diagnosed during operation by direct observation and manipulation of bones. High degree of clinical suspicion is obviously necessary to suspect and diagnose instability in both Types 2 and 3 atlantoaxial facetal instability. As there may not be any abnormality in the atlantodental interval and there may not be any dural or neural compression by the odontoid process, the instability in the latter two groups is labeled
as central or axial atlantoaxial instability. We have identified central or axial atlantoaxial instability in clinical situations with chronic or longstanding instability like Chiari formation, syringomyelia, cervical spondylosis, OPLL and Hirayama disease.18 In the presented case, there was Type 2 atlantoaxial instability.
In the presented case, atlantoaxial fixation along with multisegmental subaxial spinal fixation was successfully done. The levels of subaxial spinal fixation were essentially identified by the extension of the extradural mass, pattern of cervical kyphosis on neck flexion and by direct assessment of instability by inspection of the facets and manipulation of bones during surgery. The regression of extradural mass and reversal of tonsillar herniation was significant but incomplete. Our experience with Chiari formation suggests that both these features will probably resolve on longer follow-up evaluation.The patient improved in all his clinical symptoms. However, one wonders if atlantoaxial instability is the cause of both Chiari formation and Hirayama disease and if subaxial spinal fixation could have been avoided. Considering that Hirayama disease is by itself a rare clinical problem and association with Chiari formation and syringomyelia has never been identified in the literature, careful diagnosis and identification of cases and further experience with treatment will help clarify the issue.
References: 1. Hirayama K, Toyokura Y, Tsubaki T:Juvenile muscular atrophy of unilateral upper extremity: a new clinical entityPsychiatr Neurol Jpn 1959; 61: 2190–2197
2. Hirayama K: Juvenile muscular atrophy localized in hands and forearm: observation in 38 casesRinsho Shinkkeigaku.1972; 12: 313–324 3. Goel A, Dhar A, Shah A. Multilevel Spinal Stabilization as a Treatment for Hirayama Disease: Report of an Experience with Five Cases. World Neurosurg. 2017;99:186-191. 4. Goel A, Desai K, Muzumdar D: Atlantoaxial fixation using plate and screw method: A report of 160 treated patients. Neurosurgery 2002; 51:1351-1357. 5. Goel A, Laheri VK: Plate and screw fixation for atlanto-axial dislocation. (Technical report). Acta Neurochir (Wien)1994; 129: 47-53. 6. Roy-Camille R, Saillant G. Surgery of the cervical spine. 2. Dislocation. Fracture of the articular processes. Nouv Presse Med1972; 1:2484–5. 7. Hirayama K, Tokumaru Y: Cervical dural sac and spinal cord in juvenile muscular atrophy of distal upper extremityNeurology2000; 54: 1922– 1926 8. Pradhan S: Bilaterally symmetric form of Hirayama disease. Neurology 2009; 72 (24): 2083–2089 9. Nagaoka M. Hirayama K, Chida T, Yokochi M, Narabayashi H: Electromyographic analysis on juvenile muscular atrophy of unilateral upper extremityNo to Shinkei 1980; 32 (8): 821–828 10. Tokumaru Y, Hirayama K Cervical collar therapy for juvenile muscular atrophy of distal upper extremity (Hirayama disease): results from 38 cases. Rinsho Shinkeigaku (Clin Neurol) 2001; 41: 173–178 11. Guo X, Lu M, Xie N, Guo Q, Ni B. Multilevel anterior cervical discectomy and fusion with plate fixation for jeuvenile unilateral
muscular atrophy of the distal upper extremity accompanied by cervical kyphosis. J Spinal Disord Tech. 2014; 27 (7): E241-6. 12. Paredes I, Esteban J, Ramos A, Gonzalez P, Rivas JJ. A severe case of Hirayama disease successfully treated by anterior cervcial fusion. J Neurosurg Spine 2014; 20 (2): 191-5. 13. Ito H, Takai K, Taniguchi M. Cervical duroplasty with tenting sutures via laminoplasty for cervical flexion myelopathy in patients with Hirayama disease: successful decompression of a “tight dural canal in flexion” without spinal fusion. J Neurosurg Spine 2014; 21 (5):743-52. 14. Goel A. Is atlantoaxial instability the cause of Chiari malformation? Outcome analysis of 65 patients treated by atlantoaxial fixation. J Neurosurg Spine. 2015;22(2):116-27. 15. Goel A, Kaswa A, Shah A. Atlantoaxial Fixation for Treatment of Chiari Formation and Syringomyelia with No Craniovertebral Bone Anomaly: Report of an Experience with 57 Cases. Acta Neurochir Suppl. 2019;125:101-110. 16. Shah A, Patil A, Vutha R, Thakar K, Goel A. Recovery of Transcranial Motor Evoked Potentials After Atlantoaxial Stabilization for Chiari Formation: Report of 20 Cases. World Neurosurg. 2019;127:e644-e648. 17. Goel A:Goel’s classification of atlantoaxial “facetal” dislocation. J Craniovertebr Junction Spine2014;5 (1): 3-8. 18. Goel A. A Review of a New Clinical Entity of 'Central Atlantoaxial Instability': Expanding Horizons of Craniovertebral Junction Surgery. Neurospine. 2019;16(2):186-194.
Figure legends: Figure 1: Pre-operative Images Figure 1a: T1-weighted MRI showing Chiari formation and isointense lesion posterior to the subaxial spinal cord. Figure 1b: Contrast enhanced MRI showing the enhancing extradural mass in the posterior aspect of subaxial spinal canal. Figure 1c: T2-weighted MRI showing the mixed intensity lesion in the posterior aspect of subaxial spinal canal. Figure 1d: T2-weighted MRI with the head in extended position showing disappearance of the extradural lesion. Figure 1e: CT scan with the head in flexion showing kyphotic deformity in the subaxial cervical spine. Figure 1f: CT scan with the head in extended position showing normal spinal curvature. Figure 1g: CT scan cut passing through the facets showing posterior dislocation of the facet of atlas over the facet of axis or Type 2 atlantoaxialfacetal instability. Figure 1h: Clinical photograph of the hand showing the deformed fingers.
Figure 2: Post-operative images Figure 2a: Postoperative T1-weighted contrast enhanced MRI showing absence of contrast enhancement posterior to the subaxial spinal cord. Artifact related to implant is seen in the craniovertebral junction region. Figure 2b: Post-operative T2 weighted image showing regression of the extradural mass.
Figure 2c: Postoperative CT scan showing bone graft posterior to the midline bones. Figure 2d: Postoperative CT scan showing the implant in the atlantoaxial and subaxial regions. Figure 2e: Lateral and antero-posterior radiographs showing atlantoaxial fixation by Goel technique and subaxial spinal fixation by Camille’s transarticular fixation technique Figure 2f: Post-operative clinical photograph showing resolution of the deformity.
Abbreviations:
Nil
Conflict of Interest The authors have no conflicts of interest to disclose.