The feasibility of transpedicular screw fixation of the subaxial cervical spine in the Arab population: a computed tomography-based morphometric study.

BACKGROUND: Transpedicular screw fixation of the cervical spine provides excellent biomechanical stability. The feasibility of inserting a 3.5-mm screw in the pedicle requires a minimum pedicle diameter of 4.5 mm. This diameter allows at least 0.5 mm bony bridge medially and laterally in order to avoid pedicle violation which can result in neurovascular complications. We aim to evaluate the feasibility of this technique in Arab people since no data are available about this population. MATERIALS AND METHODS: This cross-sectional study involved a retrospective review of computed tomography scans of normal cervical spines of 99 Arab adults. Ten morphometric measurements were obtained. Data were analyzed using a p value of ≤0.05 as the cut-off level of statistical significance. RESULTS: Our sample included 63 (63.6 %) males and 36 (36.4 %) females, with a mean age of 35.5 ± 16.5 years. The morphometric parameters of C3-C7 spine pedicles were larger in males than in females. The outer pedicle width (OPW) was <4.5 mm in >25 % of all subjects at C3-C6 vertebrae. Statistically significant differences in the OPW between males and females were noted at C3 (p = 0.032) and C6 (p = 0.004). CONCLUSIONS: Inserting pedicle screws in the subaxial cervical spine is feasible among the majority of Arab people. LEVEL OF EVIDENCE: Level 3.

The Feasibility of Two Screws Anterior Fixation for Type II Odontoid Fracture Among Arabs.

STUDY DESIGN: Retrospective, cross-sectional study. OBJECTIVE: To evaluate the feasibility of two screws anterior fixation of the odontoid process among Arab adults. SUMMARY OF BACKGROUND DATA: Anterior screw fixation is the treatment of choice for type II odontoid fractures. In order to perform the procedure safely, the diameter of the odontoid process should be wide enough to allow for the placement of one or two screws. METHODS: A retrospective review of 156 computed tomography scans of the cervical spine was done. The included patients were Arabs, adults (at least 18 years old), and had no evidence of upper cervical spine trauma, deformity, infection, tumor, or surgery. The minimum external transverse diameter (METD), minimum internal transverse diameter (MITD), minimum external anteroposterior diameter (MEAD), and minimum internal anteroposterior diameter (MIAD) of the odontoid process were measured. A P value of ≤0.05 was considered as the cutoff level of statistical significance. RESULTS: Our study included 94 (60.3%) males and 62 (39.7%) females. The mean age of the subjects was 37.8 ±â€Š16.9 years (range 18-85). The mean values of the METD, MITD, MEAD, and MIAD were 8.7 ±â€Š1.0 mm, 6.0 ±â€Š1.1 mm, 10.3 ±â€Š1.0 mm, and 7.4 ±â€Š1.1 mm, respectively. Men had larger diameters compared to women. This was statistically significant for METD (P = 0.035) and MEAD (P < 0.001). The METD was <9.0 mm in 95 (60.9%) subjects, while the MITD was <8.0 mm in 153 (98.1%) subjects. These findings were not significantly different between males and females. CONCLUSION: Two screws anterior fixation of type II odontoid fracture is not feasible among the majority of Arabs. LEVEL OF EVIDENCE: 3.

Computed tomography-based morphologic and morphometric features of the coccyx among Arab adults.

STUDY DESIGN: Cross-sectional, retrospective. OBJECTIVE: To identify morphological and morphometric features of the coccyx among adult Arabs. SUMMARY OF BACKGROUND DATA: Different sacrococcygeal morphologic features were found to be associated with coccydynia. METHODS: Review of 202 computed tomographic scans of adult Arab subjects was done (mean age: 47.98 ± 16.46 yr). Sacrococcygeal morphological features including number of coccygeal segments, type of coccyx, joint fusion, joint subluxation, coccygeal spicule, coccygeal sacralization, ventral angulation of the terminal sacral segment (S5), and lateral deviation of coccygeal tip were recorded. Moreover, morphometric measurements including lengths and angles of the sacrococcygeal region were measured. Analysis of data was carried out using P value of less than 0.05 as the cutoff level of significance. RESULTS: Three coccygeal segments were present in 138 (68.3%) of individuals. The majority of the subjects had coccyx type I (96; 47.5%), II (70; 34.7%), or III (31; 15.3%); type I being more common among males (P = 0.004). Bony spicule was present in 109 (54.0%) individuals. Joint fusion, joint subluxation, coccygeal sacralization, ventral angulation of S5, and lateral deviation of coccygeal tip were present in 38.6%, 31.7%, 34.2%, 38.1%, and 38.6% of the subjects, respectively. Joint subluxation and ventral angulation of S5 were more significantly present among females (P = 0.015, P = 0.014, respectively). The mean straight and curved lengths of the coccyx were 3.3 ± 0.7 cm and 3.7 ± 0.8 cm, respectively. The sacrococcygeal structures were longer in males than in females. The mean sacrococcygeal joint angle was 149.2°± 28.1°. Based on the morphometric measurements, the coccyx was more ventrally angulated among females. CONCLUSION: The coccygeal morphology and morphometry of Arab adults share some similarities and differences with individuals of other ethnic backgrounds. Future studies should investigate the relation between these anatomic features with coccydynia among this population. LEVEL OF EVIDENCE: 3.