Cervical mismatch: the normative value of T1 slope minus cervical lordosis and its ability to predict ideal cervical lordosis.

Staub, Blake N

Lafage, Renaud

Kim, Han Jo

Shaffrey, Christopher I

Mundis, Gregory M

Hostin, Richard

Burton, Douglas

Lenke, Lawrence

Gupta, Munish C

Ames, Christopher

Klineberg, Eric

Bess, Shay

Schwab, Frank

Lafage, Virginie

International Spine Study Group

2023-06-20T15:51:11Z

2023-06-20T15:51:11Z

2018-10

2023-06-20T15:51:09Z

OBJECTIVE: Numerous studies have attempted to delineate the normative value for T1S-CL (T1 slope minus cervical lordosis) as a marker for both cervical deformity and a goal for correction similar to how PI-LL (pelvic incidence-lumbar lordosis) mismatch informs decision making in thoracolumbar adult spinal deformity (ASD). The goal of this study was to define the relationship between T1 slope (T1S) and cervical lordosis (CL).

METHODS: This is a retrospective review of a prospective database. Surgical ASD cases were initially analyzed. Analysis across the sagittal parameters was performed. Linear regression analysis based on T1S was used to provide a clinically applicable equation to predict CL. Findings were validated using the postoperative alignment of the ASD patients. Further validation was then performed using a second, normative database. The range of normal alignment associated with horizontal gaze was derived from a multilinear regression on data from asymptomatic patients.

RESULTS: A total of 103 patients (mean age 54.7 years) were included. Analysis revealed a strong correlation between T1S and C0-7 lordosis (r = 0.886), C2-7 lordosis (r = 0.815), and C0-2 lordosis (r = 0.732). There was no significant correlation between T1S and T1S-CL. Linear regression analysis revealed that T1S-CL assumed a constant value of 16.5° (R2 = 0.664, standard error 2°). These findings were validated on the postoperative imaging (mean absolute error [MAE] 5.9°). The equation was then applied to the normative database (MAE 6.7° controlling for McGregor slope [MGS] between -5° and 15°). A multilinear regression between C2-7, T1S, and MGS demonstrated a range of T1S-CL between 14.5° and 26.5° was necessary to maintain horizontal gaze.

CONCLUSIONS: Normative CL can be predicted via the formula CL = T1S - 16.5° ± 2°. This implies a threshold of deformity and aids in providing a goal for surgical correction. Just as pelvic incidence (PI) can be used to determine the ideal LL, T1S can be used to predict ideal CL. This formula also implies that a kyphotic cervical alignment is to be expected for individuals with a T1S < 16.5°.

2018.5.SPINE171232

1547-5654

1547-5646

https://hdl.handle.net/10161/28245

eng

Journal of Neurosurgery Publishing Group (JNSPG)

Journal of neurosurgery. Spine

10.3171/2018.5.spine171232

International Spine Study Group

Neck

Cervical Vertebrae

Thoracic Vertebrae

Humans

Kyphosis

Lordosis

Scoliosis

Treatment Outcome

Spinal Fusion

Postoperative Period

Retrospective Studies

Adult

Middle Aged

Female

Male

Young Adult

Cervical mismatch: the normative value of T1 slope minus cervical lordosis and its ability to predict ideal cervical lordosis.

Journal article

Shaffrey, Christopher I|0000-0001-9760-8386

31

37

1

Duke

School of Medicine

Clinical Science Departments

Orthopaedic Surgery

Neurosurgery

Published

30