Teruaki Endo

Impact of Axial Neck Pain on Quality of Life After Laminoplasty.

Study Design. A prospective study. Objective. The aim of this study was to elucidate the impact of axial pain following cervical laminoplasty on health-related quality of life (HRQOL). Summary of Background Data. Axial neck pain is a frequently encountered complication after laminoplasty. However, limited information is available regarding the time-dependent changes in axial pain and the impact of this pain on clinical outcomes, including HRQOL. Methods. One hundred sixty-two consecutive patients with cervical myelopathy underwent double-door laminoplasty using hydroxyapatite spacers from 2008 to 2012. The outcome measures included the Japanese Orthopaedic Association score (JOA score), the EuroQol 5 Dimension Questionnaire (EQ-5D), and the Short Form-36 survey (SF-36). The intensity of axial pain was assessed using an 11-point numerical rating scale (NRS). These assessments were conducted preoperatively and at 6-month, 1-year, and 2-year follow-ups. Patient satisfaction with outcome was graded using a 7-point NRS at the 2-year follow-up. Result. One hundred twenty-one patients completed the 2-year follow-up. The mean axial pain intensity decreased slightly over time; however, the decrease was not significant. The JOA score, EQ-5D score, and all SF-36 domains, excluding general health perceptions, improved significantly compared with baseline levels at the 6-month follow-up or later. Baseline axial pain intensity showed a significant negative correlation with baseline HRQOL only in the SF-36 bodily pain domain. In contrast, axial pain intensity showed significant negative correlations with all HRQOL measures at the 6-month follow-up. At the 2-year follow-up, patients with an axial pain intensity ≥3 showed significantly worse outcomes than did patients with a pain intensity <3 in the EQ-5D score, SF-36 score, and patient satisfaction grades, but not in the JOA score. Conclusion. Axial neck pain has a significant negative impact on clinical outcomes, including a wide range of HRQOL measures and patient satisfaction with outcome, in patients undergoing conventional double-door laminoplasty. Level of Evidence: 3

Early exercise in spinal cord injured rats induces allodynia through TrkB signaling

Rehabilitation is important for the functional recovery of patients with spinal cord injury. However, neurological events associated with rehabilitation remain unclear. Herein, we investigated neuronal regeneration and exercise following spinal cord injury, and found that assisted stepping exercise of spinal cord injured rats in the inflammatory phase causes allodynia. Sprague-Dawley rats with thoracic spinal cord contusion injury were subjected to assisted stepping exercise 7 days following injury. Exercise promoted microscopic recovery of corticospinal tract neurons, but the paw withdrawal threshold decreased and C-fibers had aberrantly sprouted, suggesting a potential cause of the allodynia. Tropomyosin-related kinase B (TrkB) receptor for brain-derived neurotrophic factor (BDNF) was expressed on aberrantly sprouted C-fibers. Blocking of BDNF-TrkB signaling markedly suppressed aberrant sprouting and decreased the paw withdrawal threshold. Thus, early rehabilitation for spinal cord injury may cause allodynia with aberrant sprouting of C-fibers through BDNF-TrkB signaling.

Preoperative predictors of patient satisfaction with outcome after cervical laminoplasty.

Study design Prospective cohort study. Objective The purpose of the present study was to identify the predictors of patient satisfaction with outcome after cervical laminoplasty for compressive cervical myelopathy. Methods A cohort of 143 patients with compressive myelopathy who underwent cervical double-door laminoplasty between 2008 and 2011 was studied prospectively. The principal outcome was patient satisfaction with outcome at 1 year after surgery. Patient satisfaction was graded on an ordinal scale from 1 to 7. Subjective health-related quality of life (QOL) and objective disease-specific outcome was measured by Short Form-36 (SF-36) and the Japanese Orthopaedic Association (JOA) score, respectively, before surgery and at 1-year follow-up. We evaluated the association between patient satisfaction at 1-year follow-up and various baseline parameters, including patient demographics, duration of symptoms, comorbidities, imaging findings, JOA score, and SF-36 scores. Results A total of 116 patients completed subjective and objective follow-up for a minimum of 1 year. Of 116 patients, 95 patients (81.9%) were satisfied with the outcome (“satisfied a little” or more). The unsatisfied group (“neutral” or less) showed significantly lower baseline SF-36 scores in bodily pain (BP), general health perceptions (GH), and vitality (VT) domains compared with the satisfied group. At the 1-year follow-up, SF-36 scores showed significant differences between the groups in all eight domains, whereas the JOA score showed no significant difference. Conclusions Lower baseline QOL measured by SF-36 scores, specifically in BP, GH, and VT domains, are associated with lower satisfaction with outcome after cervical laminoplasty.

An ultrastructural study on the ligamentum flavum of the cervical spine in patients with ossification of the posterior longitudinal ligament

Some histological analyses of the ossification of the posterior longitudinal ligament (OPLL) have been reported, but no ultrastructural studies of the ligamentum flavum (LF) in patients with OPLL have been published to date. To understand the pathology of the ossification of the spinal ligament, we examined, by electron microscopy, ultrastructural changes in the LF in cases of OPLL and made a comparison with the LF in cervical spondylotic myelopathy (CSM). Subjects were three men and two women with cervical OPLL who underwent longitudinal spinous process-splitting laminoplasty. During surgery, a small piece of the LF was collected from C2–C3 to C7–T1 and was then analyzed by light and electron microscopy. We observed atrophic elastic bundles with a two-layer structure and disarrangement, a partially torn area, the disappearance of microfibrils, and an enlarged interstitium with an irregular alignment of collagen fibrils. We observed some properties of a cell preceding its death: the initial phase may be the disappearance of the plasma-membrane, followed by the scattering of many organellae around its degenerated nucleus. Finally, many extracellular plasma membrane-invested particles that resemble matrix vesicles remain there without phagocytosis. These results suggest that ultrastructural abnormalities exist in the spinal ligament in cases of ossification of the spinal ligament.

Predictors of Persistent Axial Neck Pain After Cervical Laminoplasty.

Study Design. Retrospective analysis of prospective data. Objective. The aim of this study was to reveal baseline predictors of persistent postlaminoplasty neck pain. Summary of Background Data. Axial neck pain is one of the most common complications after cervical laminoplasty; however, baseline predictors of persistent postlaminoplasty neck pain are unclear. Methods. We analyzed data from 156 patients who completed a 2-year follow-up after double-door laminoplasty for degenerative cervical myelopathy. Patients rated the average intensity of axial neck pain in the last month using an 11-point numerical rating scale preoperatively and at the 2-year follow-up. The dependent variable was the presence of moderate-to-severe neck pain (numerical rating scale ≥4) at the 2-year follow-up. The independent variables included patient characteristics, baseline radiological parameters, surgical variables, baseline axial neck pain intensity, and baseline functions, which were measured by the Japanese Orthopaedic Association score and the Short Form-36 survey (SF-36). Logistic regression analysis was performed to identify independent predictors of moderate-to-severe neck pain after laminoplasty. Results. At the 2-year follow-up, 51 patients (32%) had moderate-to-severe neck pain, and 106 patients (68%) had no or mild pain. Univariate analysis revealed that the ratio of cervical anterolisthesis, ratio of current smoking, baseline neck pain intensity, and baseline SF-36 Mental Component Summary differed significantly between the groups. Multivariate logistic regression analysis showed that independent predictors of moderate-to-severe neck pain at the 2-year follow-up include the presence of anterolisthesis, current smoking, moderate-to-severe baseline neck pain, and lower SF-36 Mental Component Summary. The presence of anterolisthesis and moderate-to-severe baseline neck pain were also associated with significantly poorer physical function after surgery. Conclusion. The presence of anterolisthesis was associated not only with the highest odds ratio of persistent neck pain but also with significantly poorer functional outcomes. Indications for cervical laminoplasty should be carefully determined in patients with cervical anterolisthesis. Level of Evidence: 4

Localization of the medial branches of the cervical dorsal rami during cervical laminoplasty.

Study Design. Observational anatomic study. Objective. To give precise information on the surgical anatomy of the medial branches of the cervical dorsal rami. Summary of Background Data. The anatomy of the medial branches has not been sufficiently described. Methods. We recorded the location of the medial branches in 94 consecutive patients who underwent laminoplasty for cervical compression myelopathy. A posterior cervical approach was made along the edge of the nuchal ligament, and, after carefully detaching the trapezius muscle from the nuchal ligament; we identified the right-side branches around the semispinalis capitis muscle. We recorded the location of the branches with reference to the spinous processes and the semispinalis capitis and trapezius muscles. In 52 patients, we electrically stimulated the branches and observed the contraction of these muscles. Results. Branches were identified between C3 and C6 spinous process levels in 92 patients. A single branch was identified in 56 patients, 2 branches were identified in 35 patients, and 3 branches were identified in the remaining 1 patient. Branches were located between C3 and C4 (n = 12), between C4 and C5 (n = 80), between C5 and C6 (n = 2), and at C6 (n = 35). There were 4 patterns of final course: 52 branches passed through the medial side of the semispinalis capitis and trapezius muscles and terminated in a subcutaneous area; 50 branches penetrated the semispinalis capitis and trapezius muscles and terminated in a subcutaneous area; 12 branches terminated in the semispinalis capitis muscle; and 15 branches penetrated the semispinalis capitis and terminated at the nuchal ligament. In 19 of 52 patients tested, the semispinalis capitis muscle contracted after electrical stimulation. Conclusion. Medial branches of the cervical dorsal rami were discernible in cervical posterior approach laminoplasty and were frequently found adjacent to C4 and C5 spinous processes. The medial branches sometimes supplied motor fibers to the semispinalis capitis muscle. Knowledge of the course of these branches might be helpful for avoiding injury during laminoplasty.

Hemostatic function to regulate perioperative bleeding in patients undergoing spinal surgery: A prospective observational study

Although bleeding is a common complication of surgery, routine laboratory tests have been demonstrated to have a low ability to predict perioperative bleeding. Better understanding of hemostatic function during surgery would lead to identification of high-risk patients for bleeding. Here, we aimed to elucidate hemostatic mechanisms to determine perioperative bleeding. We prospectively enrolled 104 patients undergoing cervical spinal surgery without bleeding diathesis. Blood sampling was performed just before the operation. Volumes of perioperative blood loss were compared with the results of detailed laboratory tests assessing primary hemostasis, secondary hemostasis, and fibrinolysis. Platelet aggregations induced by several agonists correlated with each other, and only two latent factors determined inter-individual difference. Platelet aggregability independently determined perioperative bleeding. We also identified low levels of plasminogen-activator inhibitor-1 (PAI-1) and α2-plasmin inhibitor to be independent risk factors for intraoperative and postoperative bleeding, respectively. Most important independent factor to determine postoperative bleeding was body weight. Of note, obese patients with low levels of PAI-1 became high-risk patients for bleeding during surgery. Our data suggest that bleeding after surgical procedure may be influenced by inter-individual differences of hemostatic function including platelet function and fibrinolysis, even in the patients without bleeding diathesis.

Pulmonary embolism after spinal surgery: report of two cases

We present two cases of pulmonary embolism (PE) without deep venous thrombosis (DVT) after spinal surgery with an anterior approach. On the seventh day after surgery, the patients’ plasma D-dimer levels were high without symptoms, so computed tomography (CT) was performed from chest to lower limb, revealing PE without lower limb DVT. After the exam, we immediately started anticoagulation therapy with heparin and warfarin. The patients were discharged with no complications. Previous reports have documented that DVT causes most cases of PE; however, our cases had no lower limb DVT. Some reports hypothesize that anterior spinal surgery might have a differential pathogenesis of PE. Simple mechanical prophylaxis for DVT may not protect these patients. On the other hand, the administration of chemical anticoagulants therapy after spinal surgery is controversial because of the risk of epidural hematoma. We should explain the risk of PE to patients undergoing spinal surgery with an anterior approach.

Transverse vertebral fracture in osteoporotic aged patients with ankylosing spinal hyperostosis

ObjectThe object of this case series was to report the unstable transverse spinal fracture in osteoporotic ankylosing spinal hyperostosis.Clinical materials and methodsWe report eight cases from 2001 to 2008, four men and four women, aged 66–85 (Average 76.1).ResultsWe could treat three cases conservatively, but in two cases the treatment was converted to surgery due to a delayed onset of paraparesis. In total, five cases were treated surgically. Surgical procedures were laminectomy with posterior instrumentation. The surgical results were recovery to walking in two, recovery to standing with aid in two, and no gain in one. A loss of reduction occurred in two cases, with ventral displacement appearing to be the cause of the poor result in one.ConclusionsThe surgery for this situation is troublesome. We should manage the vertebral fracture in ankylosing spinal hyperostosis very carefully; keeping in mind that it might actually be unstable transverse vertebral fracture.