Spondylolisthesis : Summary

Age group	Spondylolisthesis	Indications
Pediatric	Low grade	Failure to respond to conservative treatment (9-12 months) Progressive slippage Intractable low back or radicular pain Neurological deficit and deterioration
	High grade	Neurological symptoms Severe sagittal plane spinal deformity
Adult	Low grade	Failure of non-operative treatment Progressive slippage Symptomatic and radiographically unstable isthmic spondylolisthesis
	High grade	Disabling back and/or low back pain

Mnemonic: SDSG
1. SDSG classification
2. Degree of slip
3. Spinopelvic balance
4. Global spinal balance

Degree of slip	Spinopelvic balance	Global spinal balance	Type	Remarks	Surgery
Low grade (Meyerding I and II)	PI <45 (low PI)	C7 plumb line falls over or behind femoral head (Balanced)	1	Nutcracker – clamping of posterior element of L5 between pars interarticularis of L4 and S1 during extension	Instrumentation and fusion Postural reduction
	PI 45-65 (normal PI)		2
	PI >65 (high PI)		3	Shear type –
High grade (Meyerding III, IV, V)	SS > PT (Balanced)		4
	PT > SS (Unbalanced), i.e., retroverted pelvis		5		Reduction and realignment should be considered
	PT > SS (Unbalanced), i.e., retroverted pelvis	C7 plumb line falls anterior to femoral head (Unbalanced), i.e., stooping	6		Reduction and realignment are mandatory

Parameter	Type I, Stable	Type II, Potentially unstable	Type III, Unstable
LBP	None or very mild	Primary or secondary symptom	Primary or secondary symptom
Restabilization sign	Present Grossly narrowed disc height	Some Reduced disc height	None Normal to slightly reduced disc height
Disc angle	Lordotic disc angles on flexion radiographs or <3 mm translation on dynamic films	Neutral disc angle on flexion radiographs or 3-5 mm of translation on dynamic films	Kyphotic disc angle on flexion radiographs or >5 mm translation on dynamic films
Joint effusion	No facet joint effusion on MRI	Facet joint effusion on MRI without distraction	Large facet joint effusion on MRI
Surgery	Decompression alone	Decompression and posterior fusion	Decompression and posterior fusion and interbody fusion