Proximal Junctional Kyphosis in Primary Adult Deformity Surgery

1Regions Hospital, Neurosurgery Department, Saint Paul, MN 2Washington University Medical Center, Department of Orthopaedic Surgery, St. Louis, MO 3Department of Orthopaedics, Mount Sinai School of Medicine, New York, NY 4Dept. of Orthopedic Surgery, Albert Einstein Medical Center, Philadelphia, PA 5University of Minnesota, Department of Orthopaedic Surgery, Minneapolis, MN.
Neurosurgery (Impact Factor: 3.62). 02/2013; 72(6). DOI: 10.1227/NEU.0b013e31828bacd8
Source: PubMed


BACKGROUND:: Multiple studies have reported on the prevalence of proximal junctional kyphosis (PJK) following spinal deformity surgery; however, none have demonstrated its significance with respect to functional outcome scores or revision surgery. OBJECTIVE:: To evaluate if 20° is a possible critical PJK angle in primary adult scoliosis surgery patients as a threshold for worse patient-reported outcomes. METHODS:: Clinical and radiographic data of 90 consecutive primary surgical patients at a single institution (2002-2007) with adult idiopathic/degenerative scoliosis and 2 yr minimum follow-up were analyzed. Assessment included radiographic measurements, but most notably sagittal Cobb angle of the PJ angle at pre-op, between 1-2 months, 2 yrs, and ultimate follow-up. RESULTS:: Prevalence of PJK ≥ 20° at 3.5 years was 27.8% (N=25). Those with PJK ≥ 20° at ultimate follow-up were older (mean 56 vs. 46yrs.), had lower number of levels fused (median 8 vs. 11), and were proximally fused to the lower thoracic spine more often than upper thoracic spine (all P <.001). PJK ≥ 20° was associated with significantly higher BMI and fusion to the sacrum with iliac screws (P<0.016, P<0.029 respectively). Scoliosis Research Society (SRS) outcome score changes were lower for PJK patients, but not significantly different from those in the non-PJK group. CONCLUSION:: PJK ≥ 20° in primary adult idiopathic/degenerative scoliosis does not lead to revision surgery for PJK, but is univariately associated with older age, shorter constructs starting in the lower thoracic spine, obesity, and fusion to the sacrum. The negative results, supported by SRS outcome data, provide important guidance on the post-operative management of such PJK patients.

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    ABSTRACT: Design Retrospective comparison. Objectives To determine whether the choice of proximal junctional kyphosis (PJK) definition affects reported rates and reliability of measurement of PJK for the same group of children treated with growth-friendly surgery. Background Distraction-based surgery has been associated with the development of PJK, which may lead to premature implant failure and may affect the upper instrumented level. Proximal junctional kyphosis has not been clearly defined in the literature and recent studies have used various definitions, resulting in widely varying rates of PJK. As a first step toward defining risk factors that may lead to clinically significant PJK, an evaluation of definitions of PJK should be performed. Methods The researchers analyzed radiographs of 36 children who were treated with growth-friendly surgery. The rates of PJK were determined using 3 recently described definitions. Five observers each measured the radiographs 2 weeks apart. Reliability was measured using the kappa statistic and intraclass correlation. Results At 2-year follow-up, rates of PJK varied between 6% and 42% depending on the definition used. Interobserver agreement for PJK at time 1 yielded fair agreement for definition 1 (κ = 0.31), moderate for definition 2 (κ = 0.40), and fair for definition 3 (κ = 0.38). Interobserver agreement for junctional angle at time 1 was fair (intraclass correlation coefficient [ICC], 0.48) for definition 1, good (ICC, 0.71) for definition 2, and fair (ICC, 0.55) for definition 3. Intra-observer agreement between times 1 and 2 for junctional angle was good (ICC, 0.61) for definition 1, excellent (ICC, 0.82) for Definition 2, and good (ICC, 0.69) for definition 3. Conclusions When assessed with the same group of children, rates of PJK varied depending on the definition used. Interobserver reliability was fair to moderate; however, better interobserver and intra-observer agreement were noted with definition 2. Keywords: Early-onset scoliosis, Complications, Proximal junctional kyphosis, Vertical Expandable Prosthetic Titanium ribs
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    ABSTRACT: Study Design: Retrospective review. Objective: To study time to development, clinical and radiographic characteristics, and management of proximal junctional kyphosis (PJK) following thoracolumbar instrumented fusion for adult spinal deformity (ASD). Summary of Background Data: PJK continues to be a common mode of failure following ASD surgery. Although literature exists on possible risk factors, data on management remains limited. Methods: A retrospective review of medical records of 289 consecutive ASD patients who underwent posterior segmental instrumentation incorporating at least five segments was conducted. PJK was defined as proximal kyphotic angle >10[degrees]. Results: PJK occurred in 32 patients (11%) at a mean follow-up of 34 months (1.3-61.9+/-19 mo). 16 (50%) patients were revised (mean 1.7 revisions, range: 1-3) at a mean follow up of 9.6 months (range: 0.7-40 mo); primary indications for revision were pain (n=16), myelopathy (n=6), instability (n=4), and instrumentation protrusion (n=2). Comparison of pre- and post-index surgery radiographic parameters demonstrated significant improvement in mean lumbar lordosis (LL) (24[degrees] vs. 42[degrees], P<0.001), pelvic incidence (PI)-LL mismatch (30[degrees] vs. 11[degrees], P<0.001), and pelvic tilt (PT) (29[degrees] vs. 23[degrees], P<0.011). The mean T5-T12 kyphosis worsened (30[degrees] vs. 53[degrees], P<0.001) and the mean global sagittal spinal alignment failed to improve (9.6 cm vs. 8.0 cm, P=0.76). There was no apparent relationship between the absolute PJK angle and revision surgery (P>0.05). Conclusions: The patients in this series who developed PJK had substantial pre-operative positive sagittal malalignment that remained inadequately corrected following surgery, likely resulting from a combination of inadequate surgical correction and a significant compensatory increase in thoracic kyphosis. In the absence of direct relationship between a greater PJK angle and worse clinical outcome, clinical symptoms and neurological status rather than absolute reliance on radiographic parameters should drive the decision to pursue revision surgery.
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    ABSTRACT: Proximal junctional kyphosis (PJK) is a common radiographic finding following long spinal fusions. Whether PJK leads to negative clinical outcome is currently debatable. A systematic review was performed to assess the prevalence, risk factors, and treatments of PJK. Literature search was conducted on PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials using the terms 'proximal junctional kyphosis' and 'proximal junctional failure'. Excluding reviews, commentaries, and case reports, we analyzed 33 studies that reported the prevalence rate, risk factors, and discussions on PJK following spinal deformity surgery. The prevalence rates varied widely from 6 to 61.7 %. Numerous studies reported that clinical outcomes for patients with PJK were not significantly different from those without, except in one recent study in which adult patients with PJK experienced more pain. Risk factors for PJK included age at operation, low bone mineral density, shorter fusion constructs, upper instrumented vertebrae below L2, and inadequate restoration of global sagittal balance. Prevalence of PJK following long spinal fusion for adult spinal deformity was high but not clinically significant. Careful and detailed preoperative planning and surgical execution may reduce PJK in adult spinal deformity patients.
    European Spine Journal 09/2014; 23(12). DOI:10.1007/s00586-014-3531-4 · 2.07 Impact Factor
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