Elevated Laminae Research Articles

The Importance of Lamina Size Measurement and Proper Implants Selection before Laminoplasty : Two Case Reports

<p>Open door laminoplasty using plates is a safe and effective procedure for multi-level cord compression. To achieve stable laminar arch, various types of plate have been developed and used. Now, we introduce two rare complications related to the laminar shelf of plate.</p><p>In the first case, we used the wider laminar shelf plate because the elevated lamina did not fit well into the usual laminar shelf. During follow-up, cord compression due to laminar shelf was observed.</p><p>And in the second case, the laminar shelf of plate did not fit into the elevated lamina, so we inserted it with a little bit of force. But the patient’s symptom was not improved. On CT image, the inner cortical bone of the lamina was fractured.</p><p>To prevent these complications, surgeons need to consider the thickness of the lamina and the size of the laminar shelf before surgery.</p>

Cervical restenosis caused by progressive ossification of the posterior longitudinal ligament in patients following laminoplasty: Two case reports

Abstract We report two cases of restenosis caused by the progression of thickness of ossification of the posterior longitudinal ligament (OPLL) seven and more years after laminoplasty, resulting in neurological deterioration needed for revision anterior decompressive surgeries. Neurological recovery after revision anterior excision of OPLL was poor. In both cases, the patients had progressive OPLL, with a non-ossified segment of the ossification foci, in common. After laminoplasty, they also both exhibited osseous fusion of the elevated laminae, but there was discontinuity at the interlaminar space at the peak level of OPLL. Discontinuity of the osseous fusion in the elevated laminae might cause mechanical stress increases at the non-ossified segment of the OPLL and could lead to the progression of OPLL. The present cases showed that long-term progression of OPLL can induce neurological deterioration even after sufficient posterior decompression by laminoplasty. Therefore, when considering risk factors that may be predictive of the progression of OPLL after laminoplasty, it is important to perform strict follow-up examination to check for progression to reduce the risk of myelopathy symptoms that are indicative of neurological deterioration.

Risk Factors for Delayed Hinge Fracture after Plate-Augmented Cervical Open-Door Laminoplasty.

ObjectiveDelayed hinge fracture (HF) that develops after cervical open door laminoplasty can be a source of postoperative complications such as axial pain. However, risk factors related to this complication remain unclear. We performed a retrospective clinical series to determine risk factors for delayed HF following plate-only open-door cervical laminoplasty.MethodsPatients who underwent plate-only open-door laminoplasty and had available postoperative computed tomography (CT) scans (80 patients with 270 laminae) were enrolled. Hinge status, hinge gutter location, open location, hinge width, number of screws used, operation level, and open angle were observed in the CT to determine radiographic outcome. Demographic data were collected as well. Radiographic and clinical parameters were analyzed using univariate and multivariate logistic regression analysis to determine the risk factors for HF.ResultsUnivariate logistic regression analysis results indicated poor initial hinge status, medially placed hinge gutter, double screw fixation on the elevated lamina, upper surgical level, and wide open angle as predictors for HF (p<0.05). Initial hinge status seemed to be the most powerful risk factor for HF (p=0.000) and thus was collinear with other variables. Therefore, multivariate logistic regression analysis was performed excluding initial hinge status, and the results indicated that medially placed hinge gutter, double screw fixation on the elevated lamina, and upper surgical level were risk factors for HF after adjustment for other confounding factors.ConclusionTo prevent HF and to draw a successful postoperative outcome after cervical laminoplasty, surgical and clinical precautions should be considered.

Modified Open-Door Laminoplasty Using a Ceramic Spacer and Suture Fixation for Cervical Myelopathy.

PurposeTo introduce a new simple technique using suture anchors and ceramic spacers to stabilize the elevated laminae in open-door cervical laminoplasty. Although ceramic spacers were placed in the opened laminae and fixed with nylon threads in this series, it was occasionally difficult to fix the nylon threads to the lateral mass.Materials and MethodsStudy 1: A preliminary study was conducted using a suture anchor system. Sixteen consecutive patients who underwent surgery for cervical myelopathy were prospectively examined. Study 2: The second study was performed prospectively to evaluate the feasibility of this new technique based on the result of the preliminary study. Clinical outcomes were examined in 45 consecutive patients [cervical spondylotic myelopathy (CSM)] and 43 consecutive patients (OPLL). The Japanese Orthopedic Association scoring system (JOA score), axial neck pain, and radiological findings were analyzed.Results1) In one case, re-operation was necessary due to dislodgement of the ceramic spacer following rupture of the thread. 2) In all patients, postoperative CT scans showed that the anchors were securely inserted into the bone. In the CSM group, the average JOA score improved from 9.5 points preoperatively to 13.3 at follow-up (recovery 51%). In the OPLL group, the average JOA score improved from 10.1 (5-14) points preoperatively to 14.4 (11-16) at follow-up (recovery 62%). There were no serious complications.ConclusionThe use of the suture anchor system made it unnecessary to create a hole in the lateral mass and enabled reliable and faster fixation of the HA spacers in open-door laminoplasty.

Biomechanical evaluation of the suture anchors used in open-door laminoplasty: a cadaveric study.

A cadaveric study. To determine whether the use of suture anchors is warranted in cervical laminoplasty. The use of suture anchors to stabilize elevated laminae has been popularized in laminoplasty. However, the validity of using suture anchors in laminoplasty has not been determined. Six intact fresh frozen cadavers were used. Open-door laminoplasty with a hinge on the cadaver's left side was performed on levels C3-C7. Elevated laminae were stabilized by suture anchors equipped with strain gauges, which were placed on C3, C5, and C7 left lateral masses. After surgery, the cervical spine was manually loaded passively, and the mechanical loads on each suture anchor during each motion were measured. Finally, the incision was opened again, and the failure loads of the suture anchors were also measured. After cervical loading, all elevated laminae were confirmed to be intact without dislodgement or failure of the suture anchors. The loads during left rotation and left bending were significantly higher than those during the respective motion to the right at all levels, except in rotation at C3. The loads on the C5 anchors in flexion and left rotation and on the C7 anchors in extension were relatively high. The maximum load obtained in the present study was 14.9 N, which was one order of magnitude lower than the mean failure load of the suture anchors (131.7 N). Biomechanical laterality was demonstrated, reflecting the asymmetrical nature of open-door laminoplasty. The maximum load on the suture anchors was much lower than the failure load and was consistent with the stability of the suture anchors encountered in clinical cases. This may support the validity of using suture anchors in laminoplasty, although the loads during active motion may be higher than our results. N/A.

Laminoplasty using Twinfix suture anchors to maintain cervical canal expansion

Open-door laminoplasty is a commonly performed procedure for the treatment of multiple level cervical spinal stenosis. One complication of this procedure is closure of the hinge and subsequent restenosis. Twinfix suture anchor was used in laminoplasty to stabilize cervical canal expansion. 53 patients with multiple level cervical spinal stenosis underwent laminoplasty. A unilateral open-door technique was performed for the lesion level and the elevated lamina was fixed to the lateral mass using Twinfix suture anchors. Radiography, magnetic resonance imaging, and computed tomography (CT) scanning were used for imaging studies. The Japanese Orthopedic Association score was adopted to compare clinical outcome before and after surgery. None of 53 patients who had the door secured with Twinfix suture anchors had closure of the hinge. Additionally, the suture anchors maintained their position without loosening or "pull-outs" on postoperative follow-up radiographs. The Japanese Orthopedic Association score increased significantly from 8.5 ± 3.2 before surgery to 14.2 ± 1.36 at final follow-up. Postoperative radiography and CT scan demonstrated significantly increased anteroposterior diameter of the spinal canal. There were four short-term complications: two were small dural-tears which were repaired intraoperatively without further sequelae, and the other 2 were both epidural hematomas that required emergent return to the operating room for evacuation. There were no Twinfix suture anchor-related complications. This Twinfix suture anchor can provide a firm and secure anchor for elevated open laminae in laminoplasty.

Double-door Cervical Laminoplasty With the Use of Suture Anchors

Technical note. To introduce a new simple technique using suture anchors to stabilize the elevated laminae in double-door cervical laminoplasty. Double-door cervical laminoplasty is a well-recognized procedure for the treatment of cervical spinal myelopathy. One of its complications is lamina reclosure that may cause restenosis of the spinal canal. The use of suture anchors for expansive open-door laminoplasty has previously been reported, but no study has ever been made of the use of suture anchors for double-door laminoplasty. The authors retrospectively reviewed 182 consecutive patients who had undergone double-door cervical laminoplasty using suture anchors. Data were available for 145 of the 182 patients over a minimum 12-week follow-up. These included 95 men and 50 women, and the mean age was 62 years (range, 33 to 92 y). The average follow-up period was 91 weeks (range, 12 to 313 wk). The data were analyzed for the displacement of the suture anchors, lamina reclosure, and dural expansion. No displacement of the suture anchors was observed during the follow-up period, which was confirmed with serial radiographs. Fifty-six patients underwent postoperative computed tomography more than 3 months after surgery. Lamina reclosure that was evaluated with computed tomography, was observed in 4 patients, but no spinal cord compression by the closed laminae was observed. Postoperative magnetic resonance imaging was performed in 103 patients, which revealed adequate dural expansion in all of them. There were no suture-anchor-related complications. Double-door cervical laminoplasty with suture anchors is a technically easy and safe procedure that provides secure placement of the split laminae.

Lateral Mass Anchoring Screws for Cervical Laminoplasty

Preliminary reporting of a group of patients with multiple level cervical spinal stenosis treated with a simple technique using lateral mass anchoring screw and unabsorbable suture line for securing the lamina position after expansive open-door laminoplasty. To develop an improved method for laminoplasty fixation. Laminoplasty is considered the standard procedure for treating multiple-level cervical spinal stenosis with myelopathy. Keys to successful laminoplasty are expanding and maintaining the spinal canal. There are many techniques for maintaining and securing of the expanded spinal canal such as fascial or joint capsule anchoring suture, spacer interposition, allograft, autograft, or miniplate fixation. However, many reports have indicated that these complicated and/or costly techniques are not superior to other techniques. This study reports a simple, reliable technique using a lateral mass anchoring screw for augmentation of laminoplasty fixation. Five patients with multiple level cervical spinal stenosis underwent laminoplasty. A unilateral open door technique was done for the lesion level and the elevated lamina was fixed to lateral mass anchoring screws at each level using unabsorbable suture line. The mean follow-up period was 14.5 months (9 to 34 mo). Postoperatively, the Japanese Orthopedic Association score improved from an average of 8.6 (range: 7 to10 points) to 14.2 points (range: 13 to 15 points). The average recovery rate was 67% (60% to 75%). Follow-up computed tomography scans showed the average improvement in anterioposterior diameter at each level of the cervical canal to be about 4.0 to 7.7 mm. The average open angle at each level was 19.0 to 23.8 degrees. All hinged sides had bony fusion. Although this is a small series, the preliminary results suggest that this simple lateral mass anchoring screw technique can provide a firm and secure anchor for elevated open lamina in laminoplasty.

En bloc laminoplasty without dissection of paraspinal muscles

Although conducting cervical laminoplasty in patients with multisegmental cord compression provides good neurological results, it is not without shortcomings, including C-5 palsy, axial neck pain, and undesirable radiologically detectable changes. Postoperative kyphosis and segmental instability can cause neurological problems and are believed mainly to result from neck muscle disruption. The authors developed a new laminoplasty technique, with the aim of preserving optimal muscle function. The present technique is a modification of unilateral open-door laminoplasty. By using an ultrasonic osteotome in small gaps of muscle bellies, a gutter is made without disrupting muscles, spinous processes, or their connections on the hinged side. Ceramic spacers are then positioned between elevated laminae and lateral masses at C-3, C-5, and C-7 on the opened side, which is exposed in a conventional manner. This new procedure was used to treat 37 consecutive patients with compression myelopathy. Postoperative computerized tomography (CT) scanning revealed a significant difference in a cross-sectional area of muscles between the hinged and opened side. The mean follow-up period was 40.2 months (range 24-54 months). Changes in alignment were observed in only one patient, and vertebral slippage developed in two. Performed at regular intervals, CT scanning demonstrated that the elevated laminae remained in situ throughout the study period. In using the present unilateral open-door laminoplasty technique, deep extensor muscles are left intact along with their junctions to spinous processes on the hinged side. Radiologically documented changes were minimal because the preserved muscles functioned normally immediately after the operation.

A new method of stabilising the elevated laminae in open-door laminoplasty using an anchor system

We treated 12 patients with multilevel stenosis of the cervical canal after spondylosis or ossification of the posterior longitudinal ligament by an expansive open-door laminoplasty, stabilised by using an anchor system. The preoperative sagittal diameter of the canal was 9.8 mm(±2.2) which was increased to 16.1 mm (±2.9) after surgery. The mean expansion ratio of the canal was 64% (42 to 100). The anchoring systems did not fail during the follow-up period (mean 29.5 months), and the decompression was maintained. The use of anchor systems to stabilise the posterior elements after laminoplasty is a simple and effective technique for maintaining the increased sagittal diameter of the canal.

A new method of stabilising the elevated laminae in open-door laminoplasty using an anchor system.

We treated 12 patients with multilevel stenosis of the cervical canal after spondylosis or ossification of the posterior longitudinal ligament by an expansive open-door laminoplasty, stabilised by using an anchor system. The preoperative sagittal diameter of the canal was 9.8 mm(+/-2.2) which was increased to 16.1 mm(+/-2.9) after surgery. The mean expansion ratio of the canal was 64% (42 to 100). The anchoring systems did not fail during the follow-up period (mean 29.5 months), and the decompression was maintained. The use of anchor systems to stabilise the posterior elements after laminoplasty is a simple and effective technique for maintaining the increased sagittal diameter of the canal.