Artificial lamina-assisted laminoplasty performed in seven cases

Artificial lamina after laminectomy: Progress, applications, and future perspectives

In clinical practice, laminectomy is a commonly used procedure for spinal decompression in patients suffering from spinal disorders such as ossification of ligamentum flavum, lumbar stenosis, severe spinal fracture, and intraspinal tumors. However, the loss of posterior column bony support, the extensive proliferation of fibroblasts and scar formation after laminectomy, and other complications (such as postoperative epidural fibrosis and iatrogenic instability) may cause new symptoms requiring revision surgery. Implantation of an artificial lamina prosthesis is one of the most important methods to avoid post-laminectomy complications. Artificial lamina is a type of synthetic lamina tissue made of various materials and shapes designed to replace the resected autologous lamina. Artificial laminae can provide a barrier between the dural sac and posterior soft tissues to prevent postoperative epidural fibrosis and paravertebral muscle compression and provide mechanical support to maintain spinal alignment. In this paper, we briefly review the complications of laminectomy and the necessity of artificial lamina, then we review various artificial laminae from clinical practice and laboratory research perspectives. Based on a combination of additive manufacturing technology and finite element analysis for spine surgery, we propose a new designing perspective of artificial lamina for potential use in clinical practice.

Evaluation of the rate of decompression in anterior cervical corpectomy using an intra-operative computerized tomography scan (O-Arm system)

OBJECT

The purpose of this study was to evaluate the efficacy of intra-operative computerized tomography (CT) scanning in the analysis of bone removal accuracy during anterior cervical corpectomy, in order to allow any necessary immediate correction in the event of inadequate bone removal.

METHODS

From September 2009 to December 2010 we performed an intra-operative (CT) scan using the O-Arm(™) Image system to assess the rate of central and lateral decompression in all patients treated for cervical spondylotic myelopathy by anterior cervical corpectomy and fusion.

RESULTS

Out of a population of 187 patients admitted to our department, with a diagnosis of myelopathy due to spondylotic degenerative cervical stenosis, 15 patients underwent a surgical treatment with anterior cervical corpectomy and fusion. There were nine males (60%) and six females (40%); the mean age was 52.4 years, ranging from 41 to 57 years. The pre-operative radiologic investigations (MRI and CT scans) revealed in the nine patients (60%) the extent of the compression to one vertebral body (C4 one case, C5 four cases, C6 four cases), while in the six cases (40%) the compression regarded two vertebral body (C3 and C4 one case, C4 and C5 two cases, C5 and C6 three cases). During surgery, when the decompression was judged completely, a CT scan was performed: in 11 cases (73.3%) the decompression was considered adequate, while in four cases (26.7%) it was deemed insufficient and the surgical strategy was changed in order to optimize the bone removal. In these cases an additional scan was taken to prove the efficacy of decompression, achieved in all patients.

CONCLUSION

Intra-operative CT scan performed during cervical corpectomy is a really useful tool in helping to ensure complete bone removal and the adequacy of surgery. The O-arm(™) Image system grants optimal image quality, allowing correctly assessing the rate of decompression and, in any case of doubt, allows an intra-operative evaluation of the final correct positioning of the graft.

New titanium spacer for cervical laminoplasty: initial clinical experience. Technical note

Many commercially available hydroxyapatite (HA) spacers for cervical laminoplasty have been introduced but have disadvantages such as lack of plasticity, easy cracking, and occasional difficulty in fixation by sutures. Here we present the short-term results of a newly designed titanium spacer (Laminoplasty Basket) in open-door cervical laminoplasty, and evaluated clinically and radiologically. The titanium box-shaped spacer with two arms for fixation was easily inserted and fixed into the laminoplasty space with 4-mm or 5-mm length screws after the posterior cervical arch was repositioned for the canal expansion. Twenty-one patients with cervical myelopathy due to spondylosis or ossification of the longitudinal ligament or developmental narrow canal observed for more than 6 months postoperatively were enrolled in this study. The neurological condition of these patients improved from 9.4 points on the Japanese Orthopaedic Association scale preoperatively to 13.5 points at 6 months after surgery. Postoperative radiological evaluation showed no laminar closure or implant failure and cervical spine curvature was maintained. These results seemed to have no significant difference compared with those using HA spacers. This titanium spacer is a potential substitute for conventional HA or other similar devices in cervical laminoplasty.

Cervical laminoplasty: a critical review

OBJECT

The technique of cervical laminoplasty was developed to decompress the spinal canal in patients with multi-level anterior compression caused by ossification of the posterior longitudinal ligament or cervical spondylosis. There is a paucity of data confirming its superiority to laminectomy with regard to neurological outcome, preserving spinal stability, preventing postlaminectomy kyphosis, and the development of the "postlaminectomy membrane."

METHODS

The authors conducted a metaanalysis of the English-language laminoplasty literature, assessing neurological outcome, change in range of motion (ROM), development of spinal deformity, and complications. Seventy-one series were reviewed, comprising more than 2000 patients. All studies were retrospective, uncontrolled, nonrandomized case series. Forty-one series provided postoperative recovery rate data in which the Japanese Orthopaedic Association Scale was used for assessing myelopathy. The mean recovery rate was 55% (range 20-80%). The authors of 23 papers provided data on the percentage of patients improving (mean approximately 80%). There was no difference in neurological outcome based on the different laminoplasty techniques or when laminoplasty was compared with laminectomy. There was postlaminoplasty worsening of cervical alignment in approximately 35% and with development of postoperative kyphosis in approximately 10% of patients who underwent long-term follow-up review. Cervical ROM decreased substantially after laminoplasty (mean decrease 50%, range 17-80%). The authors of studies with long-term follow up found that there was progressive loss of cervical ROM, and final ROM similar to that seen in patients who had undergone laminectomy and fusion. In their review of the laminectomy literature the authors could not confirm the occurrence of postlaminectomy membrane causing clinically significant deterioration of neurological function. Postoperative complications differed substantially among series. In only seven articles did the writers quantify the rates of postoperative axial neck pain, noting an incidence between 6 and 60%. In approximately 8% of patients, C-5 nerve root dysfunction developed based on the 12 articles in which this complication was reported.

CONCLUSIONS

The literature has yet to support the purported benefits of laminoplasty. Neurological outcome and change in spinal alignment are similar after laminectomy and laminoplasty. Patients treated with laminoplasty develop progressive limitation of cervical ROM similar to that seen after laminectomy and fusion.