Baastrup’s Disease : Interspinous Odema / Neo-arthrosis

Sagittal T1 T2 and STIR images of lumbar region spine shows:
Degenerative changes marked at L4-5 with reduced height of disc and degenerative intra discal vacume phenomenon. An abnormal linear hyper intensity of an inter spinous odema noted at the same level. 

Baastrup’s Disease

Syn: Kissing Spines Disease, intraspinous odema, intraspinous neo-arthrosis.

Baastrup’s Disease is a type of pseudo / neo-arthrosis between adjacent spinous processes.
Common in lumbar region at L4-5.

Extreme forward flexion may result in supraspinous and intraspinous ligaments sprain with development of a spur. Repeated extension interferes with the healing. An interspinous bursae may develop due to an associated supraspinous ligament laxity and intraspinous ligament breakdown. The interspinous ligament degenerates with aging resulting in the formation of a cavity, the adjacent spinous processes keep coming in contact with each other during extension and result in formation of a joint which precede pain.
Risk Factors are degenerative disc disease, Athletics, Hyper lordosis, Paraspinal muscle atrophy, Pars interarticularis defect.
Clinically characterized by localized interspinous or spinous process pain without a referral pattern, pain present for many years with progressive worsening over time.

Imaging: 
Lateral view LS spine radiograph may demonstrate sclerotic changes or flattening of adjacent spinous processes.
MRI sagittal T2 and STIR images are needed assess interspinous edema.
Bone scan with SPECT can detect increased osteoblastic activity that is associated with reactive sclerosis.

Treatment: Bed rest in semi upright sitting position, Surgical cavity resection, Surgical fusion.

References:
Haig AJ, Harris A, Quint DJ. Baastrup’s disease correlating with diffuse lumbar paraspinal atrophy: a case report. Arch Phys Med Rehabil. 2001 Feb;82(2):250-2.
Mitra R, Ghazi U, Kirpalani D, Cheng I. Interspinous ligament steroid injections for the management of Baastrup’s disease: a case report. Arch Phys Med Rehabil. 2007 Oct;88(10):1353-6.
Panagos A. Rehabilitation Medicine Quick Reference-Spine (ed. Buschbacher R.M.) New York: Demos Publishing; 2010. p. 20-21.