Associations between lumbosacral transitional anatomy types and degeneration at the transitional and adjacent segments.
BACKGROUND
The relation between specific types of lumbosacral transitional vertebra and the degree of degeneration at and adjacent to the transitional level is unclear. It is also unknown whether the adjacent cephalad segment to a transitional vertebra is prone to greater degeneration than a normal L5-S1 level.


OBJECTIVE
The purpose of this study was to evaluate the relation between specific lumbosacral transitional vertebra subtypes according to the Castellvi classification, and to determine the severity of degeneration at the transitional level and the adjacent cephalad segment.


METHODS
This study was a retrospective review.


METHODS
Ninety-two subjects with lumbosacral transitional vertebra grade 2 or higher and 94 control subjects without were retrieved from a picture archiving and communication system (PACS) search.


METHODS
Disc degeneration parameters at the transitional and at the adjacent cephalad level were measured.


METHODS
After institutional review board approval, 92 subjects (42 men; mean age, 57±16 years) with lumbosacral transitional vertebra grade 2 or higher and 94 control subjects (41 men; mean age, 51±16 years) without were retrieved from a PACS search. Degeneration of the last two segments of the lumbar spine was quantified using the Pfirrmann and Modic classifications, along with documentation of annular tears, disc herniations, and disc height, and were compared between the two groups. Furthermore, L5-S1 levels in the control subjects were compared with the adjacent cephalad segments of the transitional vertebrae for the same parameters.


RESULTS
Although the control subjects, at L5-S1, had moderate to severe degeneration by Pfirrmann grades (31%) and Modic changes ([MC] 20%), in comparison, the discs at the transitional level of the lumbosacral transitional vertebra group demonstrated significant less degeneration (3% and 1%, respectively; each p<.05). The adjacent cephalad segments of the lumbosacral transitional vertebra group showed significantly greater degeneration (Pfirrmann grade 5, 39%; MC, 30%) compared with the L4-L5 level in control subjects (16% and 11%, respectively; each p<.05). The severity of disc degeneration using all parameters correlated with the type of lumbosacral transitional vertebra. The degree of degeneration of L5-S1 in control subjects was similar to the adjacent cephalad segment in lumbosacral transitional vertebrae.


CONCLUSIONS
Increasing the mechanical connection of a lumbosacral transitional vertebra protects the disc at the transitional level and predisposes the adjacent cephalad segment to greater degeneration. The adjacent cephalad segment had a comparable degree of degeneration as the L5-S1 level in control subjects.
MRI Radiology Department, Hospital for Special Surgery, 535 E. 70th St, New York, NY 10021, USA. Electronic address: nadja.farshad@yahoo.com.
Nadja A
NA
Farshad-Amacker
Spinal Imaging, Radiology Department, Hospital for Special Surgery, 535 East 70th St, New York, NY 10021, USA.
Richard J
RJ
Herzog
Spine and Scoliosis Service, Hospital for Special Surgery, 535 East 70th St, New York, NY 10021, USA.
Alexander P
AP
Hughes
Spine and Scoliosis Service, Hospital for Special Surgery, 535 East 70th St, New York, NY 10021, USA.
Alexander
A
Aichmair
Spine and Scoliosis Service, Hospital for Special Surgery, 535 East 70th St, New York, NY 10021, USA.
Mazda
M
Farshad
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000473:pathology*; D007405:Intervertebral Disc Displacement / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000473:pathology*; D008161:Lumbosacral Region / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012447:Sacrum / Q000473:pathology*
Disc degeneration; LSTV; Lumbosacral anomalies; Lumbosacral transitional vertebra; Spine transitional anomalies; Transitional vertebra