Surgical tactics of two-segmental cervical degenerative diseases: risk factors retrospective assessment and preoperative planning.

Background: Currently, in the specialized literature there are no substantiated clinical and radiological indications for differentiated use of anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) in the treatment of patients with two-segmental cervical degenerative diseases. The objectives of this study were to (I) identify risk factors that were associated with unsatisfactory results of two-level ACDF and one-level ACCF in the treatment of patients with cervical degenerative diseases despite current perioperative management, and (II) develop a clinical and radiological algorithm for personalized surgical tactics. Methods: We retrospectively identified risk factors for the development of unsatisfactory clinical postoperative results after two-level ACDF (n=81) and one-level ACCF (n=78), operated in the period of 2009-2019 for two-segmental cervical degenerative disease. Results: Satisfactory clinical results after two-level ACDF were noted in cases with total kyphotic deformity of less than 15°; local kyphotic deformity less than 10˚; the absence of circumferential spondylotic cervical stenosis; the absence of a myelopathic lesion at the level of the vertebral body; absence of migrating intervertebral disk (IVD) hernia more than 1/3 of the vertebral body; T1 slope vertebra less than 15°; IVD degeneration according to Suzuki A. 0-II; facet joint (FJ) degeneration according to Okamoto A. I-III; interbody height (IH) more than 2 mm. Satisfactory clinical results after single-level ACCF were registered in cases with IVD degeneration according to Suzuki A. III; FJ degeneration according to Okamoto A. IV-V; IH 3 mm or less; regardless of the cervical lordosis, the angle of local kyphotic deformity and T1 slope, the presence of circumferential spondylotic cervical stenosis, the localization of the myelopathic lesion and the distance of migration IVD herniation. Conclusions: Individual planning and differentiated implementation of ACDF and ACCF in patients with two-segmental cervical degenerative disease, taking into account a comprehensive preoperative clinical and radiological assessment, contributes to the effective elimination of existing neurological symptoms, reducing the intensity of neck pain and upper limbs pain, restoring the functional state and quality of patients' lives in the minimum 24 months postoperative period, as well as reducing the number of postoperative complications and reoperations.

Seven bypasses simulation set: description and validity assessment of novel models for microneurosurgical training.

OBJECTIVE: Microsurgical training remains indispensable to master cerebrovascular bypass procedures, but simulation models for training that accurately replicate microanastomosis in narrow, deep-operating corridors are lacking. Seven simulation bypass scenarios were developed that included head models in various surgical positions with premade approaches, simulating the restrictions of the surgical corridors and hand positions for microvascular bypass training. This study describes these models and assesses their validity. METHODS: Simulation models were created using 3D printing of the skull with a designed craniotomy. Brain and external soft tissues were cast using a silicone molding technique from the clay-sculptured prototypes. The 7 simulation scenarios included: 1) temporal craniotomy for a superficial temporal artery (STA)-middle cerebral artery (MCA) bypass using the M4 branch of the MCA; 2) pterional craniotomy and transsylvian approach for STA-M2 bypass; 3) bifrontal craniotomy and interhemispheric approach for side-to-side bypass using the A3 branches of the anterior cerebral artery; 4) far lateral craniotomy and transcerebellomedullary approach for a posterior inferior cerebellar artery (PICA)-PICA bypass or 5) PICA reanastomosis; 6) orbitozygomatic craniotomy and transsylvian-subtemporal approach for a posterior cerebral artery bypass; and 7) extended retrosigmoid craniotomy and transcerebellopontine approach for an occipital artery-anterior inferior cerebellar artery bypass. Experienced neurosurgeons evaluated each model by practicing the aforementioned bypasses on the models. Face and content validities were assessed using the bypass participant survey. RESULTS: A workflow for model production was developed, and these models were used during microsurgical courses at 2 neurosurgical institutions. Each model is accompanied by a corresponding prototypical case and surgical video, creating a simulation scenario. Seven experienced cerebrovascular neurosurgeons practiced microvascular anastomoses on each of the models and completed surveys. They reported that actual anastomosis within a specific approach was well replicated by the models, and difficulty was comparable to that for real surgery, which confirms the face validity of the models. All experts stated that practice using these models may improve bypass technique, instrument handling, and surgical technique when applied to patients, confirming the content validity of the models. CONCLUSIONS: The 7 bypasses simulation set includes novel models that effectively simulate surgical scenarios of a bypass within distinct deep anatomical corridors, as well as hand and operator positions. These models use artificial materials, are reusable, and can be implemented for personal training and during microsurgical courses.

Apparent diffusion coefficient maps in the assessment of surgical patients with lumbar spine degeneration.

PURPOSE: To assess the utility of apparent diffusion coefficient (ADC) maps for the assessment of patients with advanced degenerative lumbar spine disease and describe characteristic features of ADC maps in various degenerative lumbar spinal conditions. METHODS: T1-weighted, T2-weighted and diffusion weighted (DWI) MR images of 100 consecutive patients admitted to the spinal surgery service were assessed. ADC maps were generated from DWI images using Osyrix software. The ADC values and characteristic ADC maps were assessed in the regions of interest over the different pathological entities of the lumbar spine. RESULTS: The study included 452 lumbar vertebral segments available for analysis of ADCs. Characteristic ADC map features were identified for protrusion, extrusion and sequester types of lumbar disk herniations, spondylolisthesis, reactive Modic endplate changes, Pfirrmann grades of IVD degeneration, and compromised spinal nerves. Compromised nerve roots had significantly higher mean ADC values than adjacent (p < 0.001), contralateral (p < 0.001) or adjacent contralateral (p < 0.001) nerve roots. Compared to the normal bone marrow, Modic I changes showed higher ADC values (p = 0.01) and Modic 2 changes showed lower ADC values (p = 0.02) respectively. ADC values correlated with the Pfirrmann grading, however differed from herniated and non-herniated disks of the matched Pfirrmann 3 and 4 grades. CONCLUSION: Quantitative and qualitative evaluation of ADC mapping may provide additional useful information regarding the fluid dynamics of the degenerated spine and may complement standard MRI imaging protocol for the comprehensive assessment of surgical patients with lumbar spine pathology. ADC maps were advantageous in differentiating reactive bone marrow changes, and more precise assessment of the disk degeneration state. ADC mapping of compressed nerve roots showed promise but requires further investigation on a larger cohort of patients.