Yukoh Ohara

History and Evolution of Laminoplasty

Techniques of expansive laminoplasty for degenerative cervical myelopathy and ossified posterior longitudinal ligament are described, focusing on the history of the surgical procedure. Laminectomy was the only approach for posterior decompression before Japanese orthopedic surgeons introduced laminoplasty from the 1970s to the 1980s to overcome the poor outcomes of laminectomy. Recent laminoplasty techniques offer less invasive maneuvers to the posterior cervical muscle structures to reduce axial neck pain and to obtain better functional outcome, but every operation is carried out based on the unchanged initial concept. Some recent attempts to improve the surgical results are also discussed.

Initial radiological findings utilizing titanium basket for cervical open door laminoplasty

Background: Cervical laminoplasty, utilizing different spacers to ’’keep the door open,’’ is the gold standard in Japan for treating ossification of the posterior longitudinal ligament (OPLL) and cervical spondylotic myelopathy (CSM). Here, we utilized a novel titanium ’’basket’’ spacer (Laminoplasty Basket: L-Basket; Ammtec, Tokyo) to perform open door cervical laminoplasty to keep the “door open” while also allowing for bony fusion across the open door. Methods: Twenty-seven patients with/without OPLL were treated with open door laminoplasty utilizing the basket spacer. Patients were analyzed with preoperative/postoperative JOA scores, and X-rays/computed tomography (CT) at least 12 months (range, 12–19 months) postoperatively. Results: Improvement from the preoperative JOA score of 10.3 points to the postoperative JOA of 14.8 points was noted 3 months postoperatively. There were no complications except one patient who had transient C5 palsy. Twelve months postoperatively, X-rays/CT documented fusion on both the open (62%) and hinge sides (90.2%); circumferential fusion was observed 59.8% of the time. Conclusion: This titanium “basket” spacer (Laminoplasty Basket: L-Basket; Ammtec, Tokyo) promoted bone union between the spacer and both lamina, lateral masses following cervical laminoplasty without undue complications.

Cervical Periosteal Chondroma Causing Spinal Cord or Nerve Compression: 2 Case Reports and Literature Review

BACKGROUND Chondroma is a rare benign cartilaginous tumor that originates in chondrocytes and is commonly seen in the long bones; however, it infrequently occurs in the cervical spine. CASE DESCRIPTIONS We report 2 patients with cervical periosteal chondroma that originated in the C2 vertebral body and C1 lamina as extramedullary tumors. The first patient was a 28-year-old man who presented with right upper extremity weakness and numbness. Cervical radiography revealed a bony tumor with evidence of severe spinal cord compression. The second patient was a 26-year-old woman with left occipital neuralgia. Cervical radiography demonstrated a bony tumor arising from the left C1 lateral mass that compressed the C2 nerve root. Both patients underwent surgical removal of the bony tumors, which were diagnosed as periosteal chondroma. CONCLUSIONS The authors herein summarized 16 previous reports of cervical chondroma and compared the clinical courses and treatments. Recommended treatment included maximal surgical resection, especially when significant compression of the cervical cord and signal abnormality within the cord was observed. Annual postoperative follow-up is mandatory to ensure proper neurologic improvement.

In vitro biomechanical evaluation of a monocoque plate-spacer construct for cervical open-door laminoplasty

Purpose To evaluate biomechanical differences between two surgical procedures for cervical open-door laminoplasty using human cadaveric spines. Methods Twenty-four cervical vertebrae (C4-C6) from eight fresh-frozen human cervical spines were subjected to mechanical testing after being instrumented for open-door laminoplasty using a newly designed plate-spacer device with a monocoque structure (plate-spacer group; n = 12) or by conventional miniplate-alone fixation (miniplate group; n = 12). Cantilever bending testing was performed by applying a compressive load in the cranio-caudal direction to the base of the spinous process of the reconstructed laminar arch constructs until failure and strength and stiffness of the laminar arch were determined. The results are presented as mean ± standard deviation. Results The plate-spacer group was approximately twice as strong as the miniplate group (27.6 ± 16.5 N vs. 13.5 ± 7.3 N, p < 0.05). Stiffness in the plate-spacer group exhibited the same trend (19.6 ± 9.3 N/mm vs. miniplate group: 11.4 ± 6.9 N/mm, p < 0.05). Conclusion The fixation with the monocoque plate-spacer construct for open-door laminoplasty provided higher structural properties when compared against the plate-alone fixation. The spacer in the plate-spacer construct appears to contribute by preventing large deformations of the laminar arch caused by bending in cranio-caudal direction. Future studies will be required to investigate stress/strain distribution in the laminar arch constructs.

Ossification of the Ligaments in the Cervical Spine, Including Ossification of the Anterior Longitudinal Ligament, Ossification of the Posterior Longitudinal Ligament, and Ossification of the Ligamentum Flavum

Ossification of the posterior longitudinal ligament (OPLL), ossification of the anterior longitudinal ligament (OALL), and ossification of the ligamentum flavum (OLF) sometimes are seen in the same patients, but the exact coexisting frequencies are not clear especially in the cervical region. The most frequent combination is OPLL and OALL. Cervical OPLL can coexist with thoracic OLF but is rarely associated with cervical OLF. All of these ossifying diseases of the cervical spinal ligaments are influenced by dynamic factors of the spinal column. The most frequent levels in the cervical spine affected by OPLL, OALL, and OLF are different because of anatomic differences inherent to each ligament.

Percutaneous endoscopic lumbar laminectomy

Aim: Percutaneous endoscopic lumbar laminectomy or laminotomy (PELL) is a minimally invasive surgical technique to treat lumbar canal stenosis. The procedure is undertaken using a single port endoscope, as with percutaneous endoscopic lumbar discectomy (PED). PED has become popular with spinal surgeons in Japan as a suitable surgery for lumbar disc herniation patients. Because PED has the powerful advantage of structural preservation, it allows for short hospital stays and early recovery of the patient. PELL and PED are conceptually very similar, in that they are both minimally invasive. PELL is not as popular as PED, however. The aim of the current study was to explore the reasons why. Methods: The current study reports the early experiences of surgeons at this institution in using the PELL technique, and its limitations. Results: The goal of PELL is total flavectomy and decompression of the bony structure. Currently, there are difficulties and limitations in achieving decompression using PELL with small tools. Conclusion: PELL requires much more skill than PED and the learning curve is not steep. PELL is minimally invasive for the patient, but further developments of the endoscope or procedures are required to achieve widespread use.

3D Computed-Tomography Models for In Vivo Analysis of the Neural Foramen Geometry After Anterior Cervical Decompression and Fusion

Cervical radiculopathy is a dysfunction of a nerve root in the cervical spine, which is often a result of narrowing neural foramen of the cervical spine. The cervical foramen boundaries consist of the superior and inferior pedicles, the posteroinferior margin of the superior vertebral body, the posterosuperior margin of the inferior vertebral body, and the superior and inferior articular facets (Fig 1). Because the neural foramen’s boundaries consist of two movable joints, dynamic changes occur to the neural foramen dimensions. These dynamic changes and the presence of the dorsal root ganglia present the possibility of the neural foramen contributing to the complex etiology of radiculopathy. Current surgical practice recommends an Anterior Cervical Decompression and Fusion (ACDF) procedure to treat radiculopathy. For the reasons stated above, pre- and post-surgical neural foramen geometry assessment is important to evaluate effects of the treatment. To the best of the authors’ knowledge, an accurate in vivo and computerized tomography (CT) three-dimensional (3D) model has not been demonstrated in the literature.Copyright