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Thread: Incidence, Risk Factors and Classification of Proximal Junctional Kyphosis: (etc.)

  1. #1
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    Incidence, Risk Factors and Classification of Proximal Junctional Kyphosis: (etc.)

    in case hdugger and others haven't seen this...

    http://journals.lww.com/spinejournal...ion_of.30.aspx

    Spine:
    1 January 2011 - Volume 36 - Issue 1 - p E60E68
    doi: 10.1097/BRS.0b013e3181eeaee2
    Deformity
    Incidence, Risk Factors and Classification of Proximal Junctional Kyphosis: Surgical Outcomes Review of Adult Idiopathic Scoliosis

    Yagi, Mitsuru MD, PhD*; Akilah, King B BA; Boachie-Adjei, Oheneba MD
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    Abstract

    Study Design. Retrospective case series of surgically treated adult scoliosis patients.

    Objective. To assess the incidence, risk factors and clinical outcomes of proximal junctional kyphosis (PJK) in a large series of adult idiopathic scoliosis patients undergoing long instrumented spinal fusion (.5 vertebrae). A new classification is also projected.

    Summary of Background Data. Maintaining both coronal and sagittal balance is essential in the surgical treatment of adult deformity patients. PJK is a well-recognized postoperative phenomenon in adults and adolescents after scoliosis surgery. Despite recent reports, the prevalence, clinical outcomes, and the risk factors of PJK are still controversial.

    Materials and Methods. This study is a retrospective review of the charts and radiographs of 157 consecutive patients with adult scoliosis treated with long instrumented spinal fusion. PJK was defined by a proximal junctional angle greater than 108 and at least 108 greater than the corresponding preoperative measurement. Radiographic measurements included sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL) and pelvic incidence (PI) on preoperative, immediate postoperative and at follow-up. Bone mineral density (BMD), Body mass index (BMI), age, sex, instrumentation type, surgery type, and fusion to sacrum were reviewed. Postoperative SRS outcome scores and Oswestry Disability Index (ODI) were also evaluated. PJK was graded by the severity and type. Means were compared with Student's t test and χ2 test. P value of less than 0.05 with confidence interval 95% was considered significant.

    Results. The average age was 46.9 years (2281 years) and the average Follow-up was 4.3 years (212 years). PJK occurred in 32 patients (20%) and were mostly classified as 1A (Ligamentous & mild) deformity. The SRS outcome scores and ODI did not demonstrate significant differences between PJK group and non-PJK group, four patients had additional surgeries performed for local pain. Fusion to the sacrum and posterior fusion with segmental instrumentation were significant risk for PJK (P = 0.03, P < 0.01). BMD, BMI, age, sex, and instrumentation type showed no difference. Eighty-four percent of PJK group was associated with TK 1 LL 1 PI .458 or preoperation to postoperation SVA more than 50 mm vs. 6.4% of non-PJK group (P < 0.01, P < 0.01).

    Conclusion. Despite the occurrence of PJK in 20% of adult scoliosis patients undergoing long fusion, no significant differences were found in SRS outcome scores and ODI in PJK and non-PJK patients. Fusion to the sacrum and posterior fusion with segmental instrumentation were identified as risk factors. PJK can be minimized by post-operative normalization of global sagittal alignment. A simplified classification based in severity type of PJK showed the majority in class 1A (ligamentous lesion and mild deformity).
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

  2. #2
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    Sagittal plane alignment

    Hd
    I found something that might be of interest that explains, pelvic incidence, pelvisacral angle, and pelvic lordosis.

    If you go half way down the page in this article on FIG 5, you will see diagrams of all 3 conditions. The line that runs down to the radius is the center of the hip. The pelvis and sacrum can be tilted on their own angles. So there are 2 things to worry about in this equation.
    http://www.srs.org/professionals/res...hite_paper.pdf

    As far as the .458 goes its the correlation value. Stats.
    http://en.wikipedia.org/wiki/Spearma...on_coefficient

    You will see that there are many parameters involved in sagittal balance. From my readings, surgeons were primarily concerned with coronal curves of scoliosis years ago. Now they have to add this to the equation! Fun stuff.
    Ed
    49 yr old male, now 58, the new 53...
    Pre surgery curves C12,T70,L70
    ALIF/PLIF T2-Pelvis 01/29/08, 01/31/08 7" pelvic anchors BMP
    Dr Brett Menmuir St Marys Hospital Reno,Nevada

    Bending and twisting pics after full fusion
    http://www.scoliosis.org/forum/showt...on.&highlight=

    My x-rays
    http://www.scoliosis.org/forum/attac...2&d=1228779214

    http://www.scoliosis.org/forum/attac...3&d=1228779258

  3. #3
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    Quote Originally Posted by hdugger View Post
    Thanks, Pooka.

    Can you make sense of this bit - " Eighty-four percent of PJK group was associated with TK 1 LL 1 PI .458 or preoperation to postoperation SVA more than 50 mm vs. 6.4% of non-PJK group (P < 0.01, P < 0.01)"

    I get that it has something to do with kyphosis/lordosis, but I don't know what the 1 1 .458 is about.
    Based just on the abstract, I think those are types (given numbers like Lenke gives various curve types a number descriptor) within the major curve categories (TK, LL, PI) which they either devised for this paper or used from previous papers.

    I don't understand not having a leading zero in front of the ".458". Not only are leading zeros always included by convention but they are included elsewhere in that abstract. I think they may have left off the leading zero for a reason, maybe to indicate it is not a number but more like a curve type or blend of curve types. That's just based on the other two being type "1".

    I don't know... still looks strange.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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