Table 2 A comparative review of previously conducted studies over time
Author | ATF | Year | Study design | Total number | Prevalence (%) | Place | Location | Symmetry/asymmetry | Significant outcomes and related disorders |
|---|---|---|---|---|---|---|---|---|---|
Nagar | Narrowing TF Double TF Disoriented TF | Dry cervical vertebra | 1388 | 61 (8.6%) | Israel Roman-Byzantine | C1–C7 | Bilateral and unilateral | -Osteophytes (degrees 2–4) 39 (5.5%), arthritic lesions 70 (9.9%), Schmorl’s nodes, spondylolysis, erosion of articular process, arthritis of the atlantoaxial joint, calcification of the apical ligament, failure of fusion of the spinous process. | |
Das | Double | Dry cervical vertebra | 132 | 2 (1.5%) | India | C1–C6 | Bilateral and unilateral | -The course of the VA may be distorted due to ATF. -It may be developmental or related to the variations in the course of the VA. -It can be useful for clinicians and radiologists to interpret X-rays and CT. | |
Murlimanju | Single Double Triple | Dry cervical vertebra | 363 | 6 (1.6%) | India | C1–C7 | Bilateral and unilateral | -Compression or spasm of the VA. -The osseous deformity and variations of the cervical spine. -The surgical anatomy of these variations is essential for neurosurgeons and radiologists to interpret CT and MRI. | |
Odula | Single Double Triple (types 1–5) | Dry cervical vertebra | 102 | 4 (3.9%) | Kenya | C1 | Bilateral and unilateral | -Tortuosity of the VA may cause bony erosion or impede the formation of the TF. -Incomplete TF on the right side is related to erosion by the VA due to the presence of atlas bridges. -Embryologically: a fusion of costal elements of the atlas may explain the formation of multiple TF. | |
Choudhari | Single Double | Dry cervical vertebra | 133 | 22 (23.15%) | India | C1–C7 | Unilateral: 14 (14.73%) Bilateral: 8 (8.42%) | -Compression or other pathology of such aberrant artery. -Neurological symptoms, hearing disturbances. -Double TF were observed only in the lower cervical vertebrae. -Each vertebra had at least one ATF on either side. | |
Gujar | Bilateral complete Bilateral incomplete Unilateral complete Unilateral incomplete | Dry cervical vertebra | 150 | 41 (27.33%) | India | C1–C7 | Unilateral: 27 (18%) Bilateral: 14 (9.33%) | -Unilateral ATF was more frequent than bilateral. -Variation in the course of the VA may lead to compression and neurological symptoms. -The ATF is essential for neurosurgeons during the posterior surgical approach. | |
Travan | Absence of TF Double TF Triple TF Unclosed TF Retrotransverse canal groove Arcuate foramen Supertransverse foramen | Dry cervical vertebra | 923 136 (14.7%) C1, 143 (15.5%) C2, 128 (13.9%) C3, 178 (19.3%) C4, 126 (13.6%) C5, 112 (12.1%) C6, 100 (10.8%) C7 | C1 (1.1%), C3 (2.6%), C4 (9.5; 8.5%), C5 (23.6; 23.9%), C6 (35.7%, 44.4%), C7 (20%, 10%) | (Friuli Venezia Giulia) North-eastern Italy | C1–C7 | Unilateral Bilateral | -The VA may be compressed within the arcuate foramen since the mean area of the arcuate foramen was lower than the mean area of the ipsilateral TF. -The signs and symptoms may include headache, vertigo, vegetative manifestations, auditory disruption, loss of postural muscle tone, cerebral ischemia, arterial dissection, and rotating vertebral artery blockage (bowhunter stroke). | |
Kumar | Unilateral duplication Bilateral duplication | Dry cervical vertebra | 240 | 20 (8.4%) | India (Gurgaon. Haryana) | C3–C6 | Unilateral: 16 (6.66%) Bilateral 4 (1.66%) | -The lower cervical vertebrae appear more affected by the TF variants. -Spinal surgeons and radiologists can better evaluate patients with the assistance of their understanding of these variations. -A double VA may be associated with a double TF. | |
Molinet | Shape 1, 41.32%; shape 2, 4.13%; shape 3, 18.8%; shape 4, 14.04%; shape 5, 12.39% | Dry cervical vertebra | 121 | (17.35%) | Chile | C1–C7 | 66.6% unilateral, 57.14% (right), 42.85% (left) | -These variations are useful for spine surgeons in preoperative planning and preventing vertebral vessels and sympathetic nerve injuries during surgical approaches. | |
Akhtar | 16 (9.19%): typical 9 (5.17%): atypical | Dry cervical vertebra | 174 | 25 (14.36%) | India | C1, C3–C7 | Unilateral: 20 (11.49%) Bilateral: 5 (14.36%) | -It may affect the course of VA and nerves, which causes various symptoms in patients. -It is also helpful for spine surgeons to plan surgery around the cervical vertebra and avoid postoperative complications. -These variations are also significant and helpful for anatomists, anthropologists, and radiologists. -ATF is more frequent on the right side in both typical and atypical cervical vertebrae. | |
Tellioglu | Complete double Incomplete double Agenesis: 37 (3.74%) Hypoplasia: 26 (2.63%) | MCT | 141 (90 males, 51 females) 987 vertebra | 88 (8.91%) | Turkey | C2–C6 | Bilateral | -The determination of foraminal variations could be an essential guide for neurosurgeons and radiologists in the diagnosis and treatment of diseases. -The most frequent entry level for VA through TF was C6, and the least was C4, C5, and C7. | |
Zibis | Hypoplastic 0.28% Double 1.71% Triple 0.57% Absence 2.28% Complete 1.71% | CTa | 50 (32 males, 18 females) 350 (66.4 ± 10.78 years) | 17 (4.85%) | Indo-European | C1–C7 | 12 (24%) asymmetry | -The preoperative evaluation of variations by CTa is functional. | |
Gupta | Double TF -Unilateral -Bilateral -Absence | Dry cervical vertebra | 319 TF of 161 dry cervical vertebrae | 42 (26.09%) | India | C1–C7 | Unilateral: 25 (15.53%) Bilateral: 17 (10.56%) | -All accessory TF was located posterior to the main TF except in one C4. -It would be helpful for neurosurgeons to improve surgical outcomes. -It would also help radiologists for better understanding. | |
Murugan | 15 typical cervical vertebrae, 12 (80%) had double right, one (6.6%) left, two (13.3%) bilaterally | Dry cervical vertebra | 150 | 19 (12.6%) | India | C3–C6: 15 C1, C2, C7: 4 | Unilateral/bilateral | -Radiologists must understand these variances to interpret CT and MRI. | |
Singh | Complete double 48 (20%) Unilateral double 29 (12%) Bilateral double 19 (8%) Incomplete double 15 (6%) Unilateral incomplete 8 (4%) Bilateral incomplete 5 (2%) | Dry cervical vertebra | 240 | 63 (26.25%) | India | C5–C7 | Unilateral: 38 (15.75%) Bilateral: 25 (9.5%) (asymetry) | -Compression of the neurovascular bundle may occur if compartmentalization is present. -There may be spicules of inadequate septation that might penetrate the neurovascular systems, causing vascular insufficiency and persistent discomfort. -The results may guide spinal surgeons when preparing for surgery. | |
Present | Single Double (five types: types 1–5) | 2021 | Dry cervical vertebra | 250 (500 sides) | 21 (8.4%) | Turkey | C3–C7 | Unilateral: 4 (19%) left, 6 (28.6%) right Bilateral: 11 (52.4%) | -The identification of ATF plays a crucial role in the diagnosis of variations of VA and underlying disorders. -It may provide a new strategy for identifying the possible cause of death. -The posterior location of ATF and asymmetrical distribution should be considered in the evaluation of dry cervical vertebra. -It may also give a clue for the determination of geographically based variations and population affinity. |