Is Cervical Disk Arthroplasty a Suitable Alternative to Treat Degenerative Cervical Myelopathy?

STUDY DESIGN: Systemic review. OBJECTIVE: To understand the role of cervical disk arthroplasty in the treatment of cervical myelopathy. SUMMARY OF BACKGROUND DATA: The surgical management of degenerative cervical myelopathy (DCM) most frequently involves decompression and fusion, but stiffness introduced by the fusion and adjacent segment degeneration remain problems that can result in significant morbidity. Cervical disk arthroplasty (CDA) is a newer procedure that has been demonstrated to be safe and effective for the management of cervical spine degenerative disk disease, but it has not been traditionally considered as a treatment option for DCM and the use for this indication has not been extensively studied. MATERIALS AND METHODS: A systematic review was undertaken using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using a search strategy to query all relevant articles on the use of cervical disk arthroplasty in the setting of cervical myelopathy over a 20-year period (2004-2023). This review examines the literature to assess our current understanding of the appropriateness, safety, and value of CDA in the treatment of DCM. RESULTS: A total of 844 patients received CDA across the 14 studies that met inclusion criteria, with an average of 60.3±40.4 patients per study (range: 11-152 subjects). Featured studies included 5 (35.7%) prospective studies, of which 2 were randomized. All studies had primary outcome measures of disability and/or pain scores, with the Japanese Orthopedic Association myelopathy score and neck disability index as the most commonly assessed. Four (26.7%) studies compared arthroplasty with arthrodesis. Safety of CDA for DCM was found in all studies with improvement in clinical outcome measurements. CONCLUSION: Cervical disk arthroplasty appears to be a safe and effective surgical option in the management of degenerative cervical myelopathy. Further study is needed to assess if arthroplasty provides clinical improvement in DCM of comparable magnitude and durability as traditional fusion strategies.

Perioperative Outcomes in 17,947 Patients Undergoing 2-Level Anterior Cervical Discectomy and Fusion Versus 1-Level Anterior Cervical Corpectomy for Treatment of Cervical Degenerative Conditions: A Propensity Score Matched National Surgical Quality Improvement Program Analysis.

OBJECTIVE: To compare the perioperative morbidity of 2-level anterior cervical discectomy and fusion (ACDF) with that of 1-level anterior cervical corpectomy and fusion (ACCF) for the treatment of cervical degenerative conditions. METHODS: A retrospective study of the 2005-2016 National Surgical Quality Improvement Program database for patients undergoing 2-level ACDF and 1-level ACCF was performed. Patient data included: age, sex, body mass index (BMI), functional status, and American Society of Anesthesiologists (ASA) physical status (PS) classification. Hospital data included: operative time and length of hospital stay (LOS). Thirty-day outcome data included: any, serious, and minor adverse events, return to the operating room, readmission, and mortality. After propensity matching for age, sex, ASA PS classification, functional status, and BMI, multivariate logistic regression analysis was used to compare outcomes between the 2 propensity-matched subcohorts. Finally, multivariate logistic regression that additionally controlled for operative time was performed to compare the 2 propensity-matched subcohorts. RESULTS: A total of 17,497 cases were identified, with 90.20% undergoing 2-level ACDF and 9.80% undergoing 1-level ACCF. Patients undergoing 2-level ACDF were younger, more likely to be female, had higher functional status, and had shorter operative time and LOS (p < 0.001). After propensity score matching, cases undergoing 1-level ACCF had a statistically significant higher rate of serious adverse events (p = 0.005). This difference was no longer significant after controlling for operative time. CONCLUSION: While there was noted to be additional morbidity in 1-level ACCF cases relative to 2-level ACDF cases, the lack of difference once controlling for the surgical time supports using the procedure that best accomplishes the surgical objectives.

Proposed caudal appendage classification system; spinal cord tethering associated with sacrococcygeal eversion.

INTRODUCTION: The most commonly used classification system for caudal appendages (aka human tails) dates from the 1980s and classifies appendages (tails) as either true tails or pseudotails. Advances in neuroimaging since the 1980s, however, as well as an ever-increasing number of reported cases, have made this system outdated. Sacrococcygeal eversion is a condition in which the distal sacral and coccygeal vertebrae are curved in a retroverted rather than anteverted direction. It can give rise to one type of caudal appendage. Sacrococcygeal eversion has never been associated with spinal cord tethering in any previously published reports. METHODS: We reviewed all cases of caudal appendage encountered by pediatric neurosurgeons at Children's Hospital Colorado since 2000 in which the appendage would be classified as a true tail by the most commonly used system mentioned above. We also reviewed cases of sacrococcygeal eversion encountered since 2000 by the same group of pediatric neurosurgeons. We searched the hospital electronic medical record system for additional appendages using the terms "caudal appendage" and "persistent human tail." RESULTS: We found 9 "true" tails (as classified by the most commonly used system). All 9 were associated with tethering or possible tethering of the spinal cord and 6 were associated with a low-lying conus medullaris. There were 8 cases of sacrococcygeal eversion, including 2 associated with Apert or Pfeiffer syndrome and fibroblast growth factor receptor 2 (FGFR2) mutations; these have previously been reported. There was a single case of sacrococcygeal eversion associated with Goldenhar or Turner syndrome; the former was associated with a potentially tethering lesion. Four cases of sacrococcygeal eversion not associated with any known syndrome were also found; two of these were associated with tethering or potentially tethering lesions. CONCLUSIONS: Most so-called true tails are likely cutaneous markers for spinal dysraphism and spinal cord tethering and are not remnants of the embryonic human tail. Sacrococcygeal eversion can be associated with spinal cord tethering. Based on our cases, and on review of the literature, we devised a five-category classification system for caudal appendages: (1) soft-tissue caudal appendages, (2) bony caudal appendages, (3) bony caudal prominences, (4) true tails, and (5) "other" caudal appendages.

Upward Translation of Cerebellar Tonsils following Surgical Expansion of Supratentorial Cranial Vault: A Unified Biomechanical Explanation of Chiari Type I.

Cerebellar tonsils moved significantly upward in 3 patients with Chiari type I who underwent supratentorial cranial vault expansion to alleviate intracranial pressure related to multisutural craniosynostosis. The Chiari type I deformities in these patients were the biomechanical consequence of posterior fossa-cerebellar disproportion caused by supratentorial craniocerebral disproportion secondary to multisutural craniosynostosis. The authors postulate that all cases of Chiari type I deformity share the sine qua non feature of posterior fossa-cerebellar disproportion.

PDCD10, the gene mutated in cerebral cavernous malformation 3, is expressed in the neurovascular unit.

OBJECTIVE: Mutations in the programmed cell death 10 gene, PDCD10, cause the autosomal-dominant familial cerebral cavernous malformation 3 (CCM3). Little is known about the function of this gene in disease pathogenesis. METHODS: As a first step, we analyzed the messenger ribonucleic acid (mRNA) expression of CCM3 in the embryonic and postnatal mouse brain by in situ hybridization. We generated and characterized CCM3-specific polyclonal antibodies and analyzed CCM3 protein expression in human cerebral and solid organ (extracerebral) tissues using immunohistochemistry. RESULTS: In embryonic mouse brain, CCM3 mRNA is seen in the ventricular, subventricular, and intermediate zones, the cortical plate, the developing septum, striatum, midbrain, pons, cerebellum, and medulla. In the postnatal mouse brain, we detected CCM3/PDCD10 expression in the olfactory bulb, neocortex, striatum, septal nuclei, hippocampus, dentate gyrus, thalamic and hypothalamic nuclei, inferior colliculus, Purkinje and granule cell layers and deep nuclei of the cerebellum, and in many cells and nuclei in the medulla. Similar to CCM1 and CCM2, the CCM3/PDCD10 protein is expressed in the neurovascular unit but weakly in venous structures within cortical, subcortical, and brainstem tissue. CCM3/PDCD10 protein is strongly expressed in arterial endothelium but weakly or not at all in venous endothelium of extracerebral tissue. CONCLUSION: The expression pattern of CCM3/PDCD10 in multiple organ systems displays similarities to CCM1 and CCM2. PDCD10/CCM3 is highly expressed in the neurovascular unit and in the arterial endothelium of structures within multiple organ systems, including the brain. These data provide additional information about CCM3 expression and its role in lesion development and pathogenesis.