Expansive Laminoplasty For Cervical Myelopathy Research Articles

P108. Bone bonding rate of novel hybrid hydroxyapatite spacers in cervical laminoplasty

BACKGROUND CONTEXT Expansive laminoplasty for cervical myelopathy preserves posterior structures to prevent postoperative development of instability and cervical kyphosis. It requires successful reconstruction of the laminae of the vertebral arches, as sinking or non-union of the expanded laminae may induce neurological regression, segmental motor paralysis, and postoperative axial pain. Novel hybrid hydroxyapatite (HA) spacers with interconnected porous calcium hydroxyapatite ceramic (IP-CHA) and solid ceramic with sufficient biocompatibility and mechanical strength were developed as an artificial bone substitute. PURPOSE To evaluate the usefulness and bone bonding rate of hybrid HA spacers in expansive laminoplasty. STUDY DESIGN/SETTING Expansive cervical laminoplasties with novel HA spacers composed of IP-CHA and solid ceramic were prospectively performed in cervical myelopathy patients. PATIENT SAMPLE Expansive open-door laminoplasties were performed in 146 cervical myelopathy patients: 450 hybrid HA spacers and 41 autogenous bone spacers harvested from the spinous processes were grafted into the opened side of each lamina. OUTCOME MEASURES Neurological conditions were assessed using the scoring system developed by the Japanese Orthopaedic Association (JOA), and functional improvements in the JOA scores were determined from the recovery rate (RR). METHODS The patients were followed up using computerized tomography (CT), and bonding rates for hybrid HA and autogenous spacers, bone fusion rates of the hinges of the laminae, and complications associated with the implants were examined. RESULTS Clinical symptoms significantly improved in all patients, and no major complications related to the procedure occurred. The hybrid HA spacers showed sufficient bone bonding on postoperative CT scans. The hinges fused completely in over 95% patients within 1 year. Only 4 spacers (0.9%) showed lamina sinking, and most expanded laminae maintained their positions without sinking or floating throughout the follow-up. CONCLUSIONS The hybrid HA spacers contributed to high bone fusion rates of the spacers and hinges of the laminae, and there were no complications associated with their use. Cervical laminoplasty with these spacers is safe and simple, yields sufficient fixation strength, and ensures sufficient bone bonding in the immediate postoperative period. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.

Clinical Case Report of Expansive Laminoplasty for Cervical Myelopathy Due to Both Disc Herniation and Developmental Cervical Spinal Canal Stenosis in Older Adolescents

Reports on adolescent patients with cervical myelopathy who underwent anterior cervical discectomy and fusion are scarce. However, to our knowledge, no cases of expansive laminoplasty for cervical myelopathy associated with progressive neurological deficit after a series of conservative treatment, caused by both disc herniation and developmental cervical spinal canal stenosis, have been reported.From January 2006 to July 2012, we retrospectively studied 3 patients in late adolescence presenting with cervical myelopathy who underwent expansive unilateral open-door laminoplasty at our hospital. The outcomes after the surgery were evaluated according to the Japanese Orthopedic Association scores.Symptoms presented by these patients were due to both disc herniation and developmental cervical spinal canal stenosis. No major complications occurred after the surgical procedures. The median follow-up time was 66 months (range 36–112 months). The Japanese Orthopedic Association scores after surgery showed a significant increase. Long-term outcomes after surgery were satisfactory according to the evaluation criteria for the Japanese Orthopedic Association scores. However, the ranges of motion of the cervical spine decreased, especially the ranges of motion on flexion after surgery showed a significant decrease.Expansive laminoplasty is helpful for older adolescent patients with cervical myelopathy due to both disc herniation and developmental cervical spinal canal stenosis, presenting with progressive neurological deficit after long conservative treatment.

Prediction of Clinical Results of Laminoplasty for Cervical Myelopathy Focusing on Spinal Cord Motion in Intraoperative Ultrasonography and Postoperative Magnetic Resonance Imaging

Retrospective analysis of preoperative imaging and clinical data from patients undergoing cervical expansive laminoplasty for cervical myelopathy. To investigate preoperative parameters that predict the floating status of the spinal cord at the anterior elements of the cervical spine in both intraoperative ultrasonography (US) and postoperative magnetic resonance imaging (MRI), and to evaluate the association between clinical outcome and spinal cord floating. Intraoperative US has been used to evaluate the status of the spinal cord after cervical laminoplasty for cervical myelopathy. Few studies have evaluated the predictive preoperative parameters for intraoperative US results. Imaging and clinical outcome data were collected from 101 consecutive patients who underwent cervical expansive laminoplasty for cervical myelopathy at Kaikoukai Nagoya Kyouritsu Hospital, Japan, from April 2004 to April 2008. The preoperative parameters associated with spinal cord floating in intraoperative US and postoperative MR images were investigated. Predictive parameters for the rate of recovery according to the Japanese Orthopedic Association score for cervical myelopathy at each follow-up session were also investigated. Predictive parameters for spinal cord floating after decompression in intraoperative US were the cervical vertebrae 2 to 7 (C2-C7) sagittal alignment in the standing neutral position on preoperative plain radiograph radiography (cut-off value=3 degrees) and the C5/6 "beak angle" in preoperative MRI (cut-off value=20 degrees). A predictive parameter for spinal cord floating in postoperative MRI was the C5/6 beak angle in preoperative MRI (cut-off value=21 degrees). The preoperative Japanese Orthopedic Association score and spinal cord floating at anterior elements of the cervical spine in intraoperative US were predictive parameters for clinical outcome. Intraoperative US was more useful than postoperative MRI for predicting the clinical outcome of cervical expansive laminoplasty. Knowledge of the predictive parameters for spinal cord floating after cervical expansive laminoplasty could help evaluate the limitations of posterior decompression.

Expansive Laminoplasty for Cervical Myelopathy With Interconnected Porous Calcium Hydroxyapatite Ceramic Spacers

Expansive cervical laminoplasties with interconnected porous calcium hydroxyapatite ceramic (IP-CHA) spacers were performed in cervical myelopathy patients. To evaluate the usefulness and osteoconductive capability of IP-CHA spacers in expansive laminoplasty. Expansive laminoplasty for cervical myelopathy is designed to preserve the posterior structures, so as to prevent postoperative development of instability and cervical kyphosis. The technique requires successful reconstruction of the laminae of vertebral arches, as sinking or nonunion of the expanded laminae may induce neurologic regression, segmental motor paralysis, and postoperative axial pain. A novel IP-CHA with sufficient biocompatibility and mechanical strength was developed as an artificial bone substitute. Expansive open-door laminoplasties were performed in 88 cervical myelopathy patients, and both autogenous bone spacers harvested from the spinous processes and IP-CHA spacers in combination with bone marrow were alternately grafted into the opened side of each lamina. All patients were followed up with computerized tomography scans, and bonding rates for both the IP-CHA and autogenous spacers, bone fusion rates of the hinges of the laminae, and complications associated with the implants were examined. Clinical symptoms significantly improved in all patients without major complications related to the procedure. The IP-CHA spacers demonstrated comparable bone bonding to the autogenous spacers on postoperative computerized tomography scans. The expanded laminae withstood expanded positions without sinking or floating throughout the followups, and the hinges completely fused in more than 95% of patients in both groups within 1 year. The IP-CHA spacer contributed to high bone fusion rates of the spacers and hinges of the laminae, and there were no complications associated with their use. Cervical laminoplasty with the IP-CHA spacers is a safe and simple method that yields sufficient fixation strength and provides sufficient bone bonding within a short period of time after operation.

Postoperative Segmental C5 Palsy After Cervical Laminoplasty May Occur Without Intraoperative Nerve Injury: A Prospective Study With Transcranial Electric Motor-Evoked Potentials

Intraoperative neurophysiologic monitoring with transcranial electric motor-evoked potentials was performed on patients who underwent cervical laminoplasty at a university hospital in a prospective study. To evaluate the usefulness of intraoperative spinal cord monitoring with transcranial electric motor-evoked potentials for prediction of the occurrence of segmental motor paralysis after cervical laminoplasty. Segmental motor paralysis occasionally occurs among patients who undergo expansive laminoplasty for cervical myelopathy, and it has been attributed to nerve root lesions caused by either a traumatic surgical technique or a tethering effect after decompression. Sixty-two consecutive patients (47 men and 15 women; mean age 64 years [range 32-89]) who were scheduled to undergo cervical laminoplasty under intraoperative spinal cord monitoring with transcranial electric motor-evoked potentials were included in this study. Transcranial electrical stimulations were delivered through pin-type electrodes, and the evoked potentials were recorded over the deltoid, biceps, and triceps muscles in the bilateral upper extremities and thoracic spinal cord. Intraoperative evoked potentials were successfully recorded in all muscles in 57 patients (92%), and incomplete evoked potentials were recorded in the remaining 5 patients. No critical decrease in the amplitude of the evoked potentials was observed in any of the 62 patients. All patients showed sufficient postoperative recovery from their clinical symptoms; however, postoperative transient C5 palsy occurred in 3 patients. No abnormalities were observed on transcranial electric motor-evoked potential monitoring, even in those patients who developed postoperative transient C5 palsy. These results suggest that the development of postoperative C5 palsy after cervical laminoplasty is not associated with intraoperative injury of the nerve root or the spinal cord, although the precise mechanism of its development is still unclear. Surgeons should be aware that C5 palsy is a possible complication of cervical laminoplasty, even in the absence of intraoperative nerve injury.

Open-Door Laminoplasty for Cervical Myelopathy Resulting From Adjacent-Segment Disease in Patients With Previous Anterior Cervical Decompression and Fusion

This is a retrospective study of patients with cervical myelopathy resulting from adjacent-segment disease who were treated by open-door expansive laminoplasty. The purpose of this study was to evaluate the effectiveness of laminoplasty for cervical myelopathy resulting from adjacent-segment disease. Adjacent-segment disease is one of the problems associated with anterior cervical decompression and fusion. However, the optimal surgical management strategy is still controversial. Thirty-one patients who underwent open-door expansive laminoplasty for cervical myelopathy resulting from adjacent-segment disease and age- and sex-matched 31 patients with myelopathy who underwent laminoplasty as the initial surgery were enrolled in the study. The pre- and postoperative Japanese Orthopedic Association scores (JOA scores) and the recovery rate were compared between the two groups. The average JOA scores in the patients with adjacent-segment disease and the controls were 9.2 +/- 2.6 and 9.4 +/- 2.3 before the expansive laminoplasty and 11.9 +/- 2.8 and 13.3 +/- 1.7 at the follow-up examination, respectively; the average recovery rates in the two groups were 37.1 +/- 22.4% and 50.0 +/- 21.3%, respectively (P = 0.04). The mean number of segments covered by the high-intensity lesions on the T2-weighted magnetic resonance images was 1.87 and 0.9, respectively (P = 0.001). Moderate neurologic recovery was obtained after open-door laminoplasty in patients with cervical myelopathy resulting from adjacent-segment disc disease, although the results were not as satisfactory as those in the control group. This may be attributed to the irreversible damage of the spinal cord caused by persistent compression at the adjacent segments.

Clinicoradiologic study of cervical laminoplasty with posterolateral fusion or bone graft.

A retrospective study of cervical expansive laminoplasty for cervical myelopathy from a clinicoradiologic perspective. To clarify the correlation among sagittal curvature of the cervical spine, cervical range of motion, sagittal plane translation, spinal cord atrophy, and myelopathic symptoms in patients who have undergone laminoplasty. Laminoplasties were developed to diminish the undesirable effects of laminectomy, which include postoperative kyphotic changes and instability. However, the superiority of laminoplasty over laminectomy remains controversial. Fifty-one patients with cervical spondylotic myelopathy or ossification of the cervical posterior longitudinal ligament who underwent laminoplasty were radiologically assessed before and after surgery. The index of the sagittal curvature, intervertebral range of motion, listhesis, and the transverse area of the spinal cord at the site of maximal compression were measured to evaluate interrelations among those parameters and myelopathic symptoms. There were no patients with kyphotic curvature before surgery. The postoperative curvature tended to be less lordotic. This tendency did not adversely affect postoperative symptoms. The intervertebral range of motion was significantly decreased except at C1-C2. The final C4-C5 range of motion and the postoperative myelopathic symptoms were negatively correlated. A significant correlation was observed between the postoperative spinal cord atrophy and the final myelopathic symptoms. The decrease in the lordotic curvature index and the decrease in the intervertebral range of motion after laminoplasty did not cause neurologic deterioration. In the C4-C5 intervertebral segment with a high incidence of listhesis, the restriction of the C4-C5 range of motion improved the clinical myelopathic symptoms. The radiologic prognostic factors were the postoperative restriction of intervertebral range of motion in preoperatively unstable segments and the anatomic reversibility of spinal cord insult.

Evaluation of Factors on Clinical Results Following Expansive Laminoplasty for Cervical Myelopathy

Evaluation of Factors on Clinical Results Following Expansive Laminoplasty for Cervical Myelopathy