Operative treatment of osteoporotic spinal fractures
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Transcript of Operative treatment of osteoporotic spinal fractures
George Sapkas
1st Orthopaedic Dept.“Attikon” University Hospital
Medical SchoolAthens University
Operative treatment of osteoporotic spinal fractures
• OsteoporosisOsteoporosis is a systemic disease, is a systemic disease, which results in : which results in : • progressive bone mineral loss progressive bone mineral loss • concurrent changes in bony architecture concurrent changes in bony architecture • leaving the spinal column vulnerable to leaving the spinal column vulnerable to
compression fractures, usually after minimal or compression fractures, usually after minimal or no trauma.no trauma.
Riggs:Riggs: N Engl J Med 1986 N Engl J Med 1986
Normal Bone Osteoporotic Bone
• VCFs VCFs contribute to: contribute to: • a fivefold increased risk of a fivefold increased risk of
further fracturefurther fracture by virtue of by virtue of force transmission to weak force transmission to weak vertebrae, above or below, vertebrae, above or below,
• while these have been shown while these have been shown to be associated with up to a to be associated with up to a 25%25% age-adjusted increase age-adjusted increase in in mortality.mortality.
HeaneyHeaney: Bone 1992: Bone 1992KadoKado: Arch Intern Med 1999: Arch Intern Med 1999
Traditional treatmentTraditional treatment for patients with for patients with painful VCFs includes :painful VCFs includes :
• bed restbed rest
• narcotic analgesics narcotic analgesics
• bracing bracing
resulting in increased pain because of:resulting in increased pain because of:
• acceleration bone loss acceleration bone loss
• and muscle weakness.and muscle weakness.
UthoffUthoff: JBJS 1978: JBJS 1978ConvertinoConvertino: Med Sci Exerc 1997: Med Sci Exerc 1997
Investigations Investigations
CT - scanCT - scan
MRIMRI
Bone ScanningBone Scanning
Management of osteoporotic spinal fractures
Conservative
Operative
Spinal fixationSpinal fixation
Posterior stabilizationPosterior stabilization
Anterior – Posterior
Stabilization
Π.Μ.F 80
28-7-06
Osteoporosis: T-Score: - 3.5
Posterior Correction & Stabilization
Anterior Anterior Posterior Posterior
Stabilization Stabilization
N(+)VEN(+)VE
Spinal fixationSpinal fixation
Vertebroplasty Vertebroplasty
plusplus
Technical problems Technical problems & &
Complications Complications
Related to osteoporosisRelated to osteoporosis
Early post-operative
hardware failure
Late post-operative
hardware failure
• the pullout strength, • cutout torque,
and • maximum insertional
torque for pedicle screws have been shownto correlate with bone mineral density and are significantly decreased in osteoporotic vertebrae.
Halvorson TL, Spine 1994Okuyama K, Spine 1993
Considerations for Instrumentation of the Osteoporotic Spine
Using multiple points of fixation, such as
segmental pedicle screws
• the load applied to individual screws is reduced and
• the stiffness of the overall construct is increased.
A similar principle applies to hooks or wires, although these implants generally require longer constructs than pedicle screws to provide adequate fixation
Hu SS, Spine 1997Hart R, et al, Spine 2006
In the presence of osteoporosis the strength of bone anchors may not allow
• strong compression
• distraction or
• vertebral rotation forces to be applied.
Glassman SD, et al, Instr Course Lect 2003Hu SS, Spine 1997;
Hettwer WH, et al, Advances in Osteoporotic Fracture Management 2004
Improving the bone-implant interface is fundamental to optimize pedicle screw fixation in osteoporotic bone.
Hettwer WH, et al, Advances in Osteoporotic Fracture Management 2004
Injectable cements of several types have been shown
to substantially increase the pullout strength of screw fixation in osteoporotic bone.
Glassman SD, et al, . Instr Course Lect 2003Soshi S, et al, Spine 1991
Zindrick MR, et al, Clin Orthop Relat Res 1986Taniwaki Y, et al, J.Orthop Sc 2003
However, • cement extravasation
can potentially injure surrounding structures, and
• permanent cements such as polymethylmethacrylate represent a potential locus for late infection.
Glassman SD, Instr Course Lect 2003Soshi S, et al, Spine 1991
Several unique pedicle screw designs have been described for use in osteoporotic.
• Conical screws, which better approximate pedicle morphometry, have been shown to increase pullout resistance in osteoporotic bone.
• It should be noted, however, that conical screws lose a significant portion of their strength when backed out by even a half turn, which may limit their ability to accommodate rod contour by backing out the screw.
Ono A, Brown MD, et al, J. Spinal Disord 2001Kwok AW, et al, Spine 1996
• Expandable screws offer additional improvement in pullout strength in severely osteoporotic bone.
• Clinical series using these devices, which include 21 patients with osteoporosis, demonstrated radiographic evidence of fusion in 86% of patients.
• One concern with such implants is that increasing screw diameter could fracture the pedicle placing the adjacent nerve root at risk Islam NC, et al, Spine 2001
Kostuik JP, et al, Instr Course Lect 2003Brantley AG, et al, Spine 1994
• In patients with
osteoporosis o undertapping
or o avoiding tapping
of the pilot hole altogether before screw insertion does help improve screw fixation especially in the lumbar spine
Havolosn TL, et al, Spine, 1994Carmouche JJ, et al, J. Neur.
Spine, 1998
Screw orientation also should be optimized in patients with osteoporosis. Screw triangulation via a medial orientation
• takes advantage of the bone mass between the converging screws for fixation,
• rather than only that bone lying between threads of a single screw, and
• has been shown to improve pullout strength in osteoporotic, bone.
Ono A, et al J.spinal Disord 2001Rulad CM, et al, Spine 1991
Similarly, screws oriented
o caudal or
o parallel relative to the vertebral end plate, as opposed to
o a cranial orientation, avoid increased bending moments at the screw hub in normal vertebrae, and use of this technique is also prudent in osteoporotic bone.
McKinley TO, et al, Spine 1999Youssef JA, et al, Spine 1999
• HA – coated screws
have been shown to increase pullout forces presumably by increasing botho the contact surface area
as well as o the frictional coefficient at
the bone implant interface
• The mechanical behavior of these implants over time as resorption of the HA coating occurs has not been studied, however.Hasegawa T, et al , Spine, 2005
Minimal invasive techniques
Minimal invasive techniques
Vertebroplasty - KyphoplastyVertebroplasty - Kyphoplasty
S.S.E.P.S.S.E.P. S.M.E.PS.M.E.P
Vertebroplasty
Kyphoplasty Kyphoplasty
SKy bone expander system for
percutaneous Kyphoplasty
Unilateral - BilateralUnilateral - Bilateral
V.B.S. System (Zimmer)
Vertebroplasty – KyphoplastyIndications
• Vertebral fractures (compression ± burst)
• Osteoporotic fractures (compression ± burst)
• Pathologic fractures of the spinal vertebra (metastasis)
• Haemangioma of the vertebra• Multiple myeloma
• Destruction of the posterior spinal elements
• Burst fractures (±)• Neurologic compression syndromes
(due to dislocated bony fragments)• Destruction of dorsal structures
(vertebral arch and facet joints) • Vertebra plana• Spinal infection • Allergy
(methylmethacrylate etc)• Coagulopathy • Untreated cardiovascular disturbances
Vertebroplasty – KyphoplastyContraindications
CONCLUSIONS
Osteoporosis is a particularly prevalent comorbidity in the elderly population.
Osteoporotic spinal fractures Osteoporotic spinal fractures can be treated can be treated
successfully by internal fixationsuccessfully by internal fixationor by M.I.T. or by M.I.T.
Vertebroplasty - Kyphoplastyadvantages
• May be performed under local anaesthesia as a day case
Vertebroplasty - Kyphoplasty advantages
• Provide significant relief of pain
VERTEBROPLASTY
• Seems to be more favourable in recent vertebral fractures (osteoporotic etc) without major deformity
VERTEBROPLASTYVERTEBROPLASTY
• No substantial loss of the obtained correction at the follow up
• No substantial loss of the obtained correction at the follow up
• Is unable to restore the lost height of the vertebra
VERTEBROPLASTY disadvantage
Balloon Kyphoplasty advantages
• Restores sufficiently the height of the collapsed vertebra
• Is associated with inferior possibility of cement leakage
Balloon Kyphoplasty disadvantages
• The risk of fracture in the adjacent levels is enhanced in the balloon kyphoplasty
• Increased operative time and radiation exposure
University Hospital “ATTIKON”