Long-Term Influence of C1-C2 Pedicle Screw Fixation on Occipitoatlantal Angle and Subaxial Cervical Spine in the Pediatric Population

A new radiological parameter as a predictor of dysphagia based on oro-pharyngeal stenosis in a cohort of pediatric patients undergoing mal-reduced C1-2 pedicle screw fixation

PURPOSE

C1 pedicle screw technique showed further advantages since it avoids the negative results from the sacrificed range of motion of the atlantooccipital joint compared to the occipitocervical fusion. However, some intractable complications are unavoidable. In the pediatric population, dysphagia after the atlantoaxial fixation can be accidentally serious. We aimed to determine the incidence of dysphagia in the pediatric population's cohort and its radiological predictor.

METHODS

Between January 2010 and August 2018, this retrospective study included 42 pediatric patients with atlantoaxial dislocation due to trauma. They were followed up with an average duration of 8 years (range 5-18 years). Twenty-seven were males and 15 females with a mean age of 8.2 years (range 5-15 years) when undergoing operations. Patients were classified according to the presence of postoperative dysphagia according to the Bazaz dysphagia grading scale. The measurements, including pre- and postoperative CVT/NSL, O-C2, and C2-C7 sagittal angles, were performed.

RESULTS

26.2% of the patients (11/42) experienced postoperative dysphagia. A significant difference in the postoperative CVT/NSL (115.2 ± 13.2 vs.134.8 ± 17.3, P = 0.002), ΔCVT/NSL (7.0 ± 11.2 vs. 20.3 ± 10.5, P = 0.001), ΔO-C2 (- 3.2 ± 5.8 vs. 2.1 ± 5.1, P = 0.026), postoperative nPAS (9.4 ± 3.7 vs. 12.6 ± 4.2, P = 0.031) and ΔPAS (- 1.5 ± 4.1 vs. 2.0 ± 3.5, P = 0.010) between dysphagia group and non-dysphagia group were found. Adjustment for age, gender, and BMI, the multivariate logistic analysis showed that ΔCVT/NSL < 8.35° (OR = 5.23; 95% CI 4.97-5.50; P = 0.001) and ΔO-C2 (OR = 3.34; 95% CI 3.17-3.51; P = 0.001) remained associated with the occurrence of the swallowing problems.

CONCLUSION

In comparison with ΔO-C2, ΔCVT/NSL might better predict postoperative dysphagia in children.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Surgical resection of intradural extramedullary tumors in the atlantoaxial spine via a posterior approach

BACKGROUND

The anatomical features of the atlantoaxial spine increase the difficulty of complete and safe removal of atlantoaxial intradural extramedullary (IDEM) tumors. Studies concerning surgical interventions via a posterior approach are limited.

AIM

To investigate the safety and efficacy of atlantoaxial IDEM tumor resection using a one-stage posterior approach.

METHODS

We retrospectively analyzed clinical databases for one-stage atlantoaxial IDEM tumor resection via a posterior approach between January 2008 and January 2018. The analyzed data included tumor position, histopathological type, pre- and post-operative Japanese Orthopedic Association (JOA) scores and Nurick grades, postoperative complication and recurrence status.

RESULTS

A total of 13 patients who underwent C1-C2 Laminectomy and/or unilateral facetectomy via the posterior approach were enrolled in the study. In all cases reviewed, total tumor resection and concomitant C1-C2 fusion were achieved. The average follow-up was 35.3 ± 6.9 mo (range, 26-49 mo). A statistically significant difference was noted between the preoperative JOA score (11.2 ± 1.1) and the score at the last final follow-up (15.6 ± 1.0) (P < 0.05). A statistically significant difference was noted between the preoperative Nurick grade (2.3 ± 0.9) and that at the last follow-up (1.2 ± 0.4) (P < 0.05). However, no statistically significant difference was noted between the preoperative and last follow-up C1-2 Cobb angle and C2-7 Cobb angle (P > 0.05). No mortalities, severe complications or tumor recurrence were observed during the follow-up period.

CONCLUSION

Total resection of atlantoaxial IDEM tumors is feasible and effective via a posterior approach. Surgical reconstruction should be considered to avoid iatrogenic kyphosis and improve spinal stability and overall clinical outcomes.

Cervical Pediatric Spine Trauma Managed With Open Spinal Fixation and Instrumentation and a Review of the Literature

Cervical spine injuries in the pediatric population are rare. Most injuries to the cervical spinal cord and vertebral column can be managed nonoperatively; however, surgical management may be required in certain clinical scenarios. A posterior surgical approach has been previously preferred; however, the utilization of anterior spinal fixation and instrumentation has been limited. We present a small case series of patients presenting with a traumatic cervical spine injury and detail the feasibility of craniocervical junction (CVJ) and subaxial spinal fixation in the pediatric population.

We report four cases involving pediatric patients, all of whom presented with cervical spine injuries necessitating operative intervention using a combination of the anterior and posterior operative approaches. All four patients recovered well, did not require surgical revision, and were neurologically intact at the last follow-up. 

Therefore, we conclude that spinal arthrodesis is a safe, effective way to manage spinal injuries in the cervical spine following traumatic injury.

The Effect of Straight or Lordotic Rods on Cervical Subaxial Alignment While Fusing C1-C2

BACKGROUND

The C1 lateral mass and C2 pedicle screw with rod fixation system has been used commonly in recent years. Despite the numerous reports on this technique in the literature, there are no studies regarding the effect of the angle of the rod used. We investigated the effect of rod angle on subaxial lordosis, cervical sagittal balance, and pain scores.

METHODS

Clinical records and radiologic images of 58 patients who underwent procedures between 2011 and 2016 at our clinic were assessed retrospectively. We recorded clinical findings, visual analog scale (VAS) scores, angles of cervical and segmental lordosis, and the distance between the C2 sagittal vertical axis (SVA) and the C7 posterior-superior corner.

RESULTS

A total of 36 male and 22 female patients were enrolled. A negative correlation was found between the C1-C2 lordosis angle and the C2-C7 lordosis angle irrespective of surgical technique. In patients who were operated on using 30°-angled rods, there was a postoperative increase in C1-C2 lordosis degree and an improvement in C2 cervical SVA values. Postoperative month 6 VAS scores were significantly better in the patients who were operated on with angled rods compared with those who received straight rods.

CONCLUSIONS

We believe this is because of the positive effect of the angled rod on sagittal balance. Nevertheless, prospective case-control studies should be conducted with larger groups of subjects. Furthermore, every patient should be evaluated considering the whole spinal sagittal balance.