Surgical safety of cervical pedicle screw placement with computer navigation system.

Cervical pedicle screw (CPS) may be the biomechanically best system for posterior cervical segmental fixation, but may carry a surgery-related risk. The purpose of this study was to evaluate the safety of CPS placement using computer navigation system for posterior cervical instrumented fixation and discuss its complication avoidance and management. Posterior cervical instrumented fixation using CPS was performed in a total of 128 patients during the period between 2007 and 2015. Intraoperative image guidance was achieved using a preoperative 3D CT-based or an intraoperative 3D CT-based navigation system. A total of 762 CPSs were placed in the spine level of C2 to Th3. The radiological accuracy of CPS placement was evaluated using postoperative CT. Accuracy of CPS placement using a preoperative 3D CT-based navigation system was 93.6 % (423 of 452 screws) in grade 0; the screw was completely contained in the pedicle, and accuracy of CPS placement using an intraoperative 3D CT-based navigation system was a little bit improved to 97.1 % (301 of 310 screws) in grade 0. CPS misplacement (more than half of screw) was 3.3 % (15 of 452 screws) using a preoperative 3D CT-based navigation system, and CPS misplacement (more than half of screw) was 0.6 % (2 of 310 screws) using an intraoperative 3D CT-based navigation system. In total, 38 screws (5.0 %) were found to perforate the cortex of pedicle, although any neural or vascular complications closely associated with CPS placement were not encountered. Twenty nine of 38 screws (76.3 %) were found to perforate laterally, and seven screws (18.4 %) were found to perforate medially. Image-guided CPS placement has been an important advancement to secure the safe surgery, although the use of CPS placement needs to be carefully determined based on the individual pathology.

Adjuvant multimodal treatment for spinal intradural extramedullary capillary hemangioma with subpial growth: illustrative case.

BACKGROUND: Spinal intradural extramedullary capillary hemangiomas are rare vascular lesions. Although total resection is the first treatment, the efficacy of adjuvant therapies, such as steroid or radiation therapy, has not been investigated. OBSERVATIONS: A 74-year-old man presented with progressive back pain, gait disturbance, and left chest pain. Spinal magnetic resonance imaging (MRI) revealed an intradural extramedullary lesion at the middle thoracic level. Preoperatively, systemic steroid administration improved his chest pain and reduced the tumor size. The authors performed tumor extirpation. Because the tumor strongly adhered to the pia matter, in short, the tumor accompanied with partial subpial growth, subtotal resection was performed, leaving a thin layer of the tumor. A pathological examination revealed capillary hemangioma. His gait disturbance showed rapid improvement. Stereotactic cyber knife treatment was performed for the residual tumor at 1 month after the operation. Serial MRI showed a gradual decrease in the tumor size and no recurrence at 2 years after the operation. LESSONS: When a tumor adheres to the spinal cord or nerve root, immoderate total resection should not be performed to avoid exacerbating the clinical symptoms. Adjuvant therapies, such as a systemic steroid administration or radiation therapy, may provide satisfactory control of spinal capillary hemangiomas.

Osteoporotic vertebral fractures: radiologic diagnosis, clinical and radiologic factors affecting surgical decision making: WFNS spine committee recommendations.

INTRODUCTION: With the varied literature on osteoporotic vertebral fracture that may predispose to diagnostic and management dilemma, it is timely to evaluate and streamline the evidence. The aim of this review is to create recommendations on osteoporotic vertebral fractures regarding radiologic diagnosis, and clinical and radiological factors affecting surgical decision making. EVIDENCE ACQUISITION: A computerized literature search was done using PubMed, Google scholar and Cochrane Database of Systematic Reviews from 2010 to 2020. For radiologic diagnosis, the keywords "osteoporotic vertebral fractures" and "radiologic diagnosis" were used yielding 394 articles (19 relevant articles). For clinical and radiological factors affecting surgical decision making, the keywords "osteoporotic vertebral fractures," "radiologic diagnosis," and "surgery" were used yielding 568 articles (25 relevant articles). EVIDENCE SYNTHESIS: All pertinent data were reviewed, and consensus statements were obtained in two virtual separate consensus meetings of the World Federation of Neurosurgical Societies (WFNS) Spine committee. The statements were voted and yielded positive or negative consensus using the Delphi method. CONCLUSIONS: This review summarizes the WFNS Spine Committee recommendations on the radiologic diagnosis, and clinical and radiological factors affecting surgical decision making of osteoporotic vertebral fractures.

Safety and Validity of Anterior Cervical Disc Replacement for Single-level Cervical Disc Disease: Initial Two-year Follow-up of the Prospective Observational Post-marketing Surveillance Study for Japanese Patients.

Anterior cervical disc replacement (ACDR) using cervical artificial disc (CAD) has the advantage of maintaining the range of motion (ROM) at the surgical level, subsequently reducing the postoperative risk of adjacent disc disease. Following the approval for the clinical use in Japan, a post-marketing surveillance (PMS) study was conducted for two different types of CAD, namely, Mobi-C (metal-on-plastic design) and Prestige LP (metal-on-metal design). The objective of this prospective observational multicenter study was to analyze the first 2-year surgical results of the PMS study of 1-level ACDR in Japan. A total of 54 patients were registered (Mobi-C, n = 24, MC group; Prestige LP, n = 30, PLP group). Preoperative neurological assessment revealed radiculopathy in 31 patients (57.4%) and myelopathy in 15 patients (27.8%). Preoperative radiological assessment classified the disease category as disc herniation in 15 patients (27.8%), osteophyte in 6 patients (11.1%), and both in 33 patients (61.1%). The postoperative follow-up rates at 6 weeks, 6 months, 1 year, and 2 years after ACDR were 92.6%, 87.0%, 83.3%, and 79.6%, respectively. In both groups, patients' neurological condition improved significantly after surgery. Radiographic assessment revealed loss of mobility at the surgical level in 9.5% of patients in the MC group and in 9.1% of patients in the PLP group. No secondary surgeries at the initial surgical level and no serious adverse events were observed in either group. The present results suggest that 1-level ACDR is safe, although medium- to long-term follow-up is mandatory to further verify the validity of ACDR for Japanese patients.

Simple Technique to Place the Lateral Mass Screws in the Revision Surgery after Cervical Laminoplasty for Ossification of the Posterior Longitudinal Ligament.

A lateral mass screw (LMS) is one of the standard anchor screws in posterior cervical fixation. Although the advantage of cervical LMS is that it is easier and safer to place than pedicle screw, it is sometimes difficult for surgeons to confirm the exact point for screw entry and accurate angle in cases of revision surgery. When LMS fixation is performed as revision surgery after cervical laminoplasty or laminectomy, it might be complicated to secure safe placement of the LMSs. We present a simple but practical technique involving a caliper and angle device for revision surgery after cervical laminoplasty for ossification of the posterior longitudinal ligament. In this technique, the distance between the bilateral entry points is ascertained using preoperative CT. Insertion of the screw is guided using the angle device set to 25 degrees. The technique presented here is easy and allows accurate placement of the LMSs in the posterior cervical spine, and is practical even for revision surgery.

Intramedullary spinal cord metastasis of gastric cancer.

The incidence of intramedullary spinal cord metastasis (ISCM) has been increasing because the overall survival of patients with cancer has improved thanks to recent advanced therapies, such as molecular targeted drugs, anticancer agents, and various irradiation techniques. ISCM from lung and breast cancer is the most common form among cases of ISCM. We report an extremely rare form of ISCM from gastric cancer. This 83-year-old man who had a past medical history of gastric adenocarcinoma presented with acute onset of paraparesis. Spinal magnetic resonance imaging revealed an intramedullary lesion at the upper thoracic level. Due to rapid worsening of his paresis, we decided to perform tumor extirpation. Gross total resection of the tumor was successfully performed. Pathological examination revealed poorly differentiated adenocarcinoma, suggesting the diagnosis of ISCM from gastric cancer. He demonstrated gradual improvement of paraparesis soon after surgery, although his overall survival was limited to about 6 months after surgery. When examining the etiology of acute paraparesis in elderly patients with a past medical history of cancer, ISCM should be considered in the differential diagnosis. The prognosis of ISCM from gastric cancer is still extremely limited. Unfortunately, there is currently no treatment with proven efficacy. Surgery for ISCM from gastric cancer, although a challenging procedure for spine surgeons, should be considered as a therapeutic option in these patients.

Complex Revision Surgery for Cervical Deformity or Implant Failure.

Postoperative cervical deformity sometimes occurs in the short or long term after primary surgery for cervical disorders related to the degenerative aging spine, neoplastic etiologies, hemodialysis, infection, inflammation, trauma, etc. Cervical kyphosis after posterior decompression surgery, such as laminectomy or laminoplasty, is a common problem for spine surgeons. However, revision surgery for cervical deformity is definitely one of the most challenging areas for spine surgeons. There is no doubt that surgery for cervical deformity carries a high risk of surgery-related complications that might result in aggravation of healthrelated quality of life. Revision surgery is even more challenging. Hence, spine surgeons need to assess carefully the overall severity of the underlying condition before revision surgery, and try to refine the surgical strategy to secure safe surgery. Needless to say, spine surgeons are now facing great challenges in making spine surgery a much more reliable and convincing entity.

Pharmacologic and Regenerative Cell Therapy for Spinal Cord Injury: WFNS Spine Committee Recommendations.

This is a review article examining the pharmacologic and regenerative cell therapy for spinal cord injury. A literature search during last 10 years were conducted using key words. Case reports, experimental (nonhuman) studies, papers other than English language were excluded. Up-to-date information on the pharmacologic and regenerative cell therapy for spinal cord injury was reviewed and statements were produced to reach a consensus in 2 separate consensus meeting of WFNS Spine Committee. The statements were voted and reached a consensus using Delphi method. Pharmacologic and regenerative cell therapy for spinal cord injury have long been an interest of many experimental and clinical researches. Clinical studies with methylpredinisolone have not shown clear cut benefit. Other drugs such as Rho inhibitor, minocycline, riluzole, granulocyte colony-stimulating factor have also been tried without significant benefits. Regenerative cell therapy using different types of stem cells, different inoculation techniques, and scaffolds have undergone many trials highlighting the efficacies of cells and their limitations. This review article summarizes the current knowledge on pharmacologic and regenerative cell therapy for spinal cord injury. Unfortunately, there is a need for further experimental and human trials to recommend effective pharmacologic and regenerative cell therapy.

Safety of anterior cervical discectomy and fusion using titanium-coated polyetheretherketone stand-alone cages: Multicenter prospective study of incidence of cage subsidence.

This multicenter prospective study investigated cage subsidence in anterior cervical discectomy and fusion (ACDF) using titanium-coated polyetheretherketone (PEEK) stand-alone cages. This study recruited patients who underwent 1- or 2-level ACDF using titanium-coated PEEK stand-alone cages for cervical disc disease. Patients with acute trauma or past cervical spine operations were excluded. Sixty-two cages in 42 patients were eligible for analysis. Minimum follow-up was 6 months after ACDF. Significant cage subsidence was recognized in 11 of 62 cages (17.7%). Cage subsidence was predominantly moderate (14.5%), with severe subsidence found in only 2 cages (3.2%). The slowest occurrence of cage subsidence was 6 months after surgery, in 4 of 11 cages. Frequency of cage subsidence did not differ significantly between patients <65 and ≥65 years old. Patients with and without cage subsidence both demonstrated significant improvement of neurological function. Cage subsidence resulted in aggravation of local angle, but finally did not affect C2-7 angle or cervical tilt angle. Severe cage subsidence was found in only 3.2% of patients within 6 months after ACDF. Cage subsidence aggravated local angle, but finally did not affect C2-7 angle or cervical tilt angle. One- or 2-level ACDF using titanium-coated PEEK stand-alone cages appears safe and justified, even in elderly patients.

Upper Cervical Spine Trauma: WFNS Spine Committee Recommendations.

Craniovertebral junction (CVJ) trauma is a challenging clinical condition. Being a highly mobile functional unit at the junction of the skull and the vertebral column, traumatic events in this area may produce devastating neurological complications and death. Additionally, many of the CVJ traumatic injuries can be left undiagnosed or even raise difficult treatment dilemmas. We present a literature review in the format of recommendations on the diagnosis and management of different scenarios for upper cervical trauma and produce recommendations, which can be applicable to various areas of the globe.