Relationship between degree of focal kyphosis correction and neurological outcomes for patients undergoing cervical deformity correction surgery

Journal of Neurosurgery: Spine April 5, 2013 [epub] Matthew Grosso, BS; Roy Hwang MD; Thomas Mroz MD; Edward Benzel MD;Michael Steinmetz MD These authors performed a retrospective review of 36 patients with myelopathic symptoms who underwent cervical deformity correction surgery.Preoperative and postoperative radiographic findings of the degree of kyphosis werecompared with functional outcome with minimum follow-up of 2 years. Functionaloutcomes were assessed with the modified Japanese Orthopaedic Association(mJOA). KEY POINTS FROM THIS STUDY: 1) The reversal of normal cervical curvature, as seen in kyphosis, can occurthrough a variety of mechanisms and can lead to mechanical pain, neurologicaldysfunction, and functional disabilities. Kyphosis of the cervical spine can be adebilitating condition that leads to significant neurological dysfunction. 2) Surgical intervention is warranted in patients with sufficiently symptomaticdeformities in an attempt to correct the deformed cervical spine. 3) The results of this study showed significantly improved neurological outcomeswith better correction of focal kyphosis and with attainment of global lordosis. 4) The authors’ results suggest that the degree of correction of focal kyphosisdeformity correlates with improved neurological outcomes. 5) The authors also saw a positive relationship between attainment of globallordosis and improved mJOA scores. 6) The normal lordotic curvature of the cervical spine is critical to maintainingsagittal alignment and spinal balance. 7) It is believed that the neurological symptoms seen in cervical kyphosis are aresult of deformity-induced anatomical changes that apply pressure to the spinalcord and nerve roots. 8) Narrowing of the neuroforamen caused by disc degeneration may result inradiculopathy, while stretching or impingement of the spinal cord, often at the apexof the [kyphotic] deformity, can lead to myelopathic symptoms. 9) As kyphosis progresses, spinal cord and nerve root stresses often increase,leading to further neurological debilitation. 10) It is thought that the tension created from kyphotic deformity on the anteriorspinal cord results in compression on the regional blood supply and nerves. 11) Our study found that the degree of correction of focal kyphosis deformitycorrelates with improved neurological outcomes. 12) The extent of cervical kyphosis is commonly associated with progression ofneurological symptoms. 13) These authors found that a greater degree of focal kyphosis correction wasassociated with a greater degree of neurological improvement. 14) In patients with focal kyphosis, a greater degree of correction may assist inachieving greater neurological improvements. 15) In correction surgery for cervical kyphotic deformity, better outcomes werereported in patients who achieved lordosis than in those who maintained kyphosis. COMMENTS FROM DAN MURPHY: Although this is a surgical study, it has a number of chiropractic applications: 1) Cervical kyphosis adversely affects spinal cord function, probably bycontributing to anterior spinal cord ischemia and pressure on the spinal cord andnerve roots. 2) Cervical kyphosis can cause: A)) Mechanical pain B)) Neurological dysfunction C)) Functional disabilities 3) Correction of cervical lordosis is desirable. 4) The better the correction of focal cervical kyphosis and the better theachievement of global cervical lordosis, the better the improvement of neurologicaloutcomes. Some chiropractic techniques, especially Chiropractic Biophysics, have proveneffective (published in PubMed), nonsurgical clinical protocols to restore cervicallordosis. Chiropractic Biophysics has taught these techniques to chiropractors formore then 30 years.