discussion about where to stop caudal level during cervical lateral mass fusion, whether stopping at c6, c7 or T1

2. Introduction
 Posterior cervical decompression and fusion (PCF) is often
recommended for patients with cervical spondylotic
myelopathy, multilevel cervical stenosis, and deformity.
 Caudal fusion level vary when extending toward the
cervicothoracic junction- still debatable.
 Some studies suggest a radiographic and clinical benefit to
routine extension to the thoracic spine whereas others do not
(significant increase in blood loss, operative morbidity and
length of stay associated with thoracic extension).

3. Materials and Methods
 Four-center radiographic and clinical database.
 Patients that had undergone 3 or more level posterior cervical
fusions for degenerative disease.
 from January 2013 to May 2015 with at least 2 years of postop
follow-up data.

4. Materials and Methods (Cont.)
 Patients were divided into:
 Group I: fusion ending at C6 or C7.
 Group II: fusion extending into the thoracic spine.
 Radiographic measurements (cervical lordosis, T1 slope, and
C2–C7 sagittal plumbline) were performed by an independent
experienced clinical researcher.

5. Definitions
 Cervical lordosis was defined as the sagittal Cobb angle
between C2 and C7 vertebral bodies.
 T1 slope was defined as the angle formed by the intersection
of a line drawn tangential to the superior end plate of T1 and a
horizontal reference line.
 C2–C7 sagittal plumbline was defined as the distance
between C2 plumbline and C7.

8. Analysis
 For the analysis:-
 Age groups: ≤65 years and >65 years.
 Obesity: obese BMI >30, non-obese as BMI ≤30.
 Smoking status was divided as current, past >6
months, nonsmokers.
 The odds ratio: the odds of smoking patients
undergoing revision surgery compared with the odds
of revision surgery for non-smoking patients.
 Subgroup analysis for caudal levels as C6 versus C7.
 Demographic, clinical and radiographic data were compared
between the two groups.

9. Results

10. Results (Cont.)

11. Results (Cont.)

12. Results (Cont.)
 No significant statistical differences in change (2 weeks vs. 2
years postop, p>.05) In:
 Mean C2-C7 sagittal plumbline (group I: 4.4±2.6
mm; group II: 4.8± 2.9 mm).
 T1 slope (group I: 2.9±2.7°; group II: 3.2±2.8°).
 Mean cervical lordosis at 2 years postop improved in both
(group I vs. group II: 12.8° vs. 14.1°).

13. Results (Cont.)
 Significant improvements in mean clinical outcomes (ie, visual
analog scale (VAS) and Oswestry disability index (ODI) at 2
years follow ups in both groups but there were no statistically
significant differences between them (p>0.05).
 Mean VAS improvements (preop vs. 2 years postop) in group I
and group II were 6.1±2.3 versus 2.3±2.0; and 5.4±2.7 versus
3.0±1.9, respectively.
 Mean ODI improvements (preop vs. 2 years postop) in group I
and group II were 51.7±18.7 versus 21.9±17.7 and 43.5±21.3
versus 27.4±19.2, respectively

14. Results (Cont.)
 For the two groups, the four-way interaction model (age × BMI
× sex × smoking status) did not have any significant effects on
change (2 weeks vs. 2-year postop) in mean cervical lordosis,
C2–C7 sagittal plumbline and T1 slope (p>.05).
 Similarly, the model did not reveal any significant four-way
interaction (age × BMI × sex × smoking status) effect on
patient reported outcomes (ie, VAS and ODI) at 2 years
postop in two groups (p>.05)

15. Revision Surgery

16. C6 versus C7 subgroup analysis
 Patients: 80 vs 88
 Mean length of hospital stay, operative time, total blood loss,
clinical improvement and radiologic findings did not differ
significantly between the two groups (p>.05)
 Rate of revision was comparatively lower for patients with
caudal level as C7 than C6 (7.9% vs. 8.8%).
 Rates of adjacent segment disease were lower for C7 than C6
group (3.4% vs. 3.8%)

17. Conclusion
 Extending the fusion into the thoracic spine resulted in a lower
rate of nonunion.
 No other clear radiographic or patient reported outcome
measures (PROMS) benefits.
 patients with cervical caudal end level experienced lower
blood loss, shorter operative time and hospital length of stay.
 The existing literature has mixed recommendations for caudal
end level in posterior cervical reconstruction.

18. Conclusion (Cont.)
 In this study: no significant advantages of routine extension of
the posterior cervical fusion into the thoracic spine except for
lower pseudoarthrosis rate.
 On the other hand, there was marked increase in morbidity
associated with thoracic extension.
 In caudal end C6 vs C7: C7 had lower rate of revision (7.9%
vs. 8.8%) and adjacent segment disease (3.4% vs. 3.8%) than
those fused to C6.

19.  Thank You.

20. Reference
 https://pubmed.ncbi.nlm.nih.gov/32890781/