Clinical Experiences and Usefulness of Cervical Posterior Stabilization with Polyaxial Screw-Rod System

Objective

The objective of this study is to investigate the safety, surgical efficacy, and advantages of a polyaxial screw-rod system for posterior occipitocervicothoracic arthrodesis.

Methods

Charts and radiographs of 32 patients who underwent posterior cervical fixation between October 2004 and February 2006 were retrospectively reviewed. Posterior cervical polyaxial screw-rod fixation was applied on the cervical spine and/or upper thoracic spine. The surgical indication was fracture or dislocation in 18, C1-2 ligamentous injury with trauma in 5, atlantoaxial instability by rheumatoid arthritis (RA) or diffuse idiopathic skeletal hyperostosis (DISH) in 4, cervical spondylosis with myelopathy in 4, and spinal metastatic tumor in 1. The patients were followed up and evaluated based on their clinical status and radiographs at 1, 3, 6 months and 1 year after surgery.

Results

A total of 189 screws were implanted in 32 patients. Fixation was carried out over an average of 3.3 spinal segment (range, 2 to 7). The mean follow-up interval was 20.2 months. This system allowed for screw placement in the occiput, C1 lateral mass, C2 pars, C3-7 lateral masses, as well as the lower cervical and upper thoracic pedicles. Satisfactory bony fusion and reduction were achieved and confirmed in postoperative flexion-extension lateral radiographs and computed tomography (CT) scans in all cases. Revision surgery was required in two cases due to deep wound infection. One case needed a skin graft due to necrotic change. There was one case of kyphotic change due to adjacent segmental degeneration. There were no other complications, such as cord or vertebral artery injury, cerebrospinal fluid leak, screw malposition or back-out, or implant failure, and there were no cases of postoperative radiculopathy due to foraminal stenosis.

Conclusion

Posterior cervical stabilization with a polyaxial screw-rod system is a safe and reliable technique that appears to offer several advantages over existing methods. Further biomechanical testings and clinical experiences are needed in order to determine the true benefits of this procedure.     

T1 Slope and Cervical Sagittal Alignment on Cervical CT Radiographs of Asymptomatic Persons

Objective

We performed a retrospective analysis of medical records and radiographic images of patients who never underwent spinal treatment including diagnosis. The objective of this study is to explain the biomechanical and physiologic characteristics of cervical alignment related to thoracic inlet angle including T1 slope changes in each individual.

Methods

We reviewed the cervical CT radiographs of 80 patients who visited ENT outpatient clinic without any symptom, diagnosis and treatment of cervical spine from January 2011 to September 2012. All targeted people were randomized without any prejudice. We assessed the data-T1 slope, Cobb''s angle C2-7, neck tilt, sagittal vertical axis (SVA) C2-7 and thoracic inlet angle by the CT radiographs.

Results

The relationships between each value were analyzed and we concluded that Cobb''s angle C2-7 gets higher as the T1 slope gets higher, while the SVA C2-7 value decreases.

Conclusion

We propose that the T1 slope is background information in deciding how much angle can be made in the cervical spinal angle of surgical lordotic curvature, especially severe cervical deformity.     

Customized Cranioplasty Implants Using Three-Dimensional Printers and Polymethyl-Methacrylate Casting

Objective

The prefabrication of customized cranioplastic implants has been introduced to overcome the difficulties of intra-operative implant molding. The authors present a new technique, which consists of the prefabrication of implant molds using three-dimensional (3D) printers and polymethyl-methacrylate (PMMA) casting.

Methods

A total of 16 patients with large skull defects (>100 cm²) underwent cranioplasty between November 2009 and April 2011. For unilateral cranial defects, 3D images of the skull were obtained from preoperative axial 1-mm spiral computed tomography (CT) scans. The image of the implant was generated by a digital subtraction mirror-imaging process using the normal side of the cranium as a model. For bilateral cranial defects, precraniectomy routine spiral CT scan data were merged with postcraniectomy 3D CT images following a smoothing process. Prefabrication of the mold was performed by the 3D printer. Intraoperatively, the PMMA implant was created with the prefabricated mold, and fit into the cranial defect.

Results

The median operation time was 184.36±26.07 minutes. Postoperative CT scans showed excellent restoration of the symmetrical contours and curvature of the cranium in all cases. The median follow-up period was 23 months (range, 14-28 months). Postoperative infection was developed in one case (6.2%) who had an open wound defect previously.

Conclusion

Customized cranioplasty PMMA implants using 3D printer may be a useful technique for the reconstruction of various cranial defects.     

Posterior Cervical Fixation with a Nitinol Shape Memory Loop for Primary Surgical Stabilization of Atlantoaxial Instability: A Preliminary Report

Objective

To evaluate a new posterior atlantoaxial fixation technique using a nitinol shape memory loop as a simple method that avoids the risk of vertebral artery or nerve injury.

Methods

We retrospectively evaluated 14 patients with atlantoaxial instability who had undergone posterior C1-2 fusion using a nitinol shape memory loop. The success of fusion was determined clinically and radiologically. We reviewed patients'' neurologic outcomes, neck disability index (NDI), solid bone fusion on cervical spine films, changes in posterior atlantodental interval (PADI), and surgical complications.

Results

Solid bone fusion was documented radiologically in all cases, and PADI increased after surgery (p<0.05). All patients remained neurologically intact and showed improvement in NDI score (p<0.05). There were no surgical complications such as neural tissue or vertebral artery injury or instrument failure in the follow-up period.

Conclusion

Posterior C1-2 fixation with a nitinol shape memory loop is a simple, less technically demanding method compared to the conventional technique and may avoid the instrument-related complications of posterior C1-2 screw and rod fixation. We introduce this technique as one of the treatment options for atlantoaxial instability.     

The Management of Bilateral Interfacetal Dislocation with Anterior Fixation in Cervical Spine : Comparison with Combined Antero-Posterior Fixation

Objective

Combined antero-posterior fixation has been a standard method for bilateral interfacetal dislocation in cervical spine. The purpose of this study is to evaluate the efficacy and complication of anterior cervical stabilization in treatment of bilateral interfacetal dislocation.

Methods

A total of 65 cases of traumatic bilateral interfacetal dislocation in cervical spine who were managed in our institution, from Mar. 1997 to Feb. 2006, were included in this study. Closed reduction was tried in all cases before operation. If closed reduction was accomplished successfully, only anterior cervical fixation was performed (Group I), and attempted to place screws bicortically as possible with unicortical screws. If failed, posterior open reduction with fixation was first tried, followed by anterior cervical fixation (Group II). All patients were evaluated for neurological outcome and radiological evidence of healing.

Results

The Group I included 47 patients and the Group II, 18 patients. The improvement of Frankel grade and increase of mean cervical lordosis angles were not statistically different between two groups. Screw-plate system used did not influence the outcome. On follow up, solid bone fusion was evident and there were no cases of instability in both groups.

Conclusion

Our study demonstrated that anterior cervical fixation on BID is safe and effective in comparison with combined antero-posterior cervical fixation.     

The Relationship between Neck Pain and Cervical Alignment in Young Female Nursing Staff

Objective

Degenerative changes in the cervical spine are commonly accompanied by cervical kyphosis which can cause neck pain. This study examined the relationship between neck pain and cervical alignment.

Methods

A total of 323 female nursing staff from our hospital were enrolled. Sagittal radiographs of the cervical spine, Body Mass Index (BMI), Visual Analogue Scale (VAS) measures of neck and arm pain, Neck Disability Index (NDI) and the Short Form (36) Health Survey (SF-36 scores) were obtained and reviewed retrospectively. Global lordosis (GL) of the cervical spine was measured on radiograph images. Correlations between GL and questionnaire scores were investigated using the following three methods : 1) correlation between GL and questionnaire scores among the entire sample; 2) subgroup analysis of patients with "kyphosis (KYP) : GL scores<0" vs. those with "lordosis (LOR) : GL scores>0" on questionnaire measures; and 3) subgroup analysis of patients with pain vs. those without pain, on GL and questionnaire measures.

Results

There was no significant correlation between GL and any questionnaire measure. There was a significant difference between the mean GLs of the KYP and LOR groups, but there were no group differences in BMI, age or any questionnaire measures. There was no difference between the pain (n=92) and pain-free (n=231) groups in age, BMI or GL, but there were differences in neck, and arm pain, and physical function and NDI scores.

Conclusions

Our data suggest that kyphotic deformity was not associated with neck pain.     

Posterior Cervical Fixation with Nitinol Shape Memory Loop in the Anterior-Posterior Combined Approach for the Patients with Three Column Injury of the Cervical Spine : Preliminary Report

Objective

The authors reviewed clinical and radiological outcomes in patients with three column injury of the cervical spine who had undergone posterior cervical fixation using Nitinol shape memory alloy loop in the anterior-posterior combined approach.

Materials

Nine patients were surgically treated with anterior cervical fusion using an iliac bone graft and dynamic plate-screw system, and the posterior cervical fixation using Nitinol shape memory loop (Davydov™) at the same time. A retrospective review was performed. Clinical outcomes were assessed using the Frankel grading method. We reviewed the radiological parameters such as bony fusion rate, height of iliac bone graft strut, graft subsidence, cervical lordotic angle, and instrument related complication.

Results

Single-level fusion was performed in five patients, and two-level fusion in four. Solid bone fusion was presented in all cases after surgery. The mean height of graft strut was significantly decreased from 20.46±9.97 mm at immediate postoperative state to 18.87±8.60 mm at the final follow-up period (p<0.05). The mean cervical lordotic angle decreased from 13.83±11.84° to 11.37±6.03° at the immediate postoperative state but then, increased to 24.39±9.83° at the final follow-up period (p<0.05). There were no instrument related complications.

Conclusion

We suggest that the posterior cervical fixation using Nitinol shape memory alloy loop may be a simple and useful method, and be one of treatment options in anterior-posterior combined approach for the patients with the three column injury of the cervical spine.     

Axial Neck Pain after Cervical Laminoplasty

Objective

It has been demonstrated that cervical laminoplasty is an effective and safe method of treating multi-level cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament. However, recent reports have suggested that axial neck pain is frequently encountered after cervical laminoplasty. The aim of the present study was to determine clinical significance of the C7 spinous process on axial neck pain after cervical laminoplasty.

Methods

A total of 31 consecutive patients that underwent cervical laminoplasty between March 2002 and December 2008 were reviewed. The authors evaluated and compared axial neck pain and lordotic angle in patients that underwent C7 spinous process preserving surgery (group 1, n = 16) and in patients in which the C7 spinous process was sacrificed (group 2, n = 15).

Results

Severe or moderate early axial pain occurred in 56.2% of patients in group 1 and in 86.6% in group 2. Severe or moderate late axial pain occurred in 12.5% in group 1 and in 73.3% in group 2. Eighty-Six percent of patients in group 2 and 43% in group 1 experienced aggravation of their axial neck pain during the early postoperative period. Aggravation of axial neck pain during early postoperative period was less common in group 1 but not statistically significant (p = 0.073). Sixty-six percent of patients in group 2 and 12% in group 1 had aggravated axial neck pain at late postoperative period and aggravation of late axial neck pain was significantly less common in group 1 (p = 0.002).

Conclusion

The present study demonstrates that C7 spinous process preserving laminoplasty decreases the incidence of aggravated axial neck pain after cervical laminoplasty.     

The Clinical Experience of Computed Tomographic-Guided Navigation System in C1-2 Spine Instrumentation Surgery

Objective

To identify the accuracy and efficiency of the computed tomographic (CT)-based navigation system on upper cervical instrumentation, particularly C1 lateral mass and C2 pedicle screw fixation compared to previous reports.

Methods

Between May 2005 and March 2014, 25 patients underwent upper cervical instrumentation via a CT-based navigation system. Seven patients were excluded, while 18 patients were involved. There were 13 males and five females; resulting in four degenerative cervical diseases and 14 trauma cases. A CT-based navigation system and lateral fluoroscopy were used during the screw instrumentation procedure. Among the 58 screws inserted as C1-2 screws fixation, their precise positions were evaluated by postoperative CT scans and classified into three categories : in-pedicle, non-critical breach, and critical breach.

Results

Postoperatively, the precise positions of the C1-2 screws fixation were 81.1% (47/58), and 8.6% (5/58) were of non-critical breach, while 10.3% (6/58) were of critical breach. Most (5/6, 83.3%) of the critical breaches and all of non-critical breaches were observed in the C2 pedicle screws and there was only one case of a critical breach among the C1 lateral mass screws. There were three complications (two vertebral artery occlusions and a deep wound infection), but no postoperative instrument-related neurological deteriorations were seen, even in the critical breach cases.

Conclusion

Although CT-based navigation systems can result in a more precise procedure, there are still some problems at the upper cervical spine levels, where the anatomy is highly variable. Even though there were no catastrophic complications, more experience are needed for safer procedure.     

Effects of long-term combination treatment with valproate and atypical antipsychotics on bone mineral density and bone metabolism in premenopausal patients with bipolar disorder: a preliminary study

Objective

We investigated bone mineral density (BMD) and bone metabolism in female bipolar patients who were undergoing long-term treatment with valproate combined with a low-dose atypical antipsychotic.

Methods

Nineteen premenopausal women with bipolar disorder who were treated with valproate combined with atypical antipsycho-tics for at least 2 years were evaluated. The BMD was measured at lumbar spine and femur sites using dual-energy X-ray absorptiometry (DE-XA). The biochemical markers of bone turnover and circulating levels of gonadal hormones were assessed. Subjects with abnormal DEXA scans were compared to those with normal scans.

Results

Nine (47%) of nineteen subjects showed osteopenia or osteoporosis. The T-score for subjects with abnormal DEXA scans was -1.988. Decreased BMD was more prominent in the proximal femur than in the lumbar spine. Subjects with abnormal DEXA scans had high phosphorus and low testosterone levels relative to subjects with normal scans (p=0.008 and p=0.028, respectively). There was a significant negative correlation between phosphorus, osteocalcin, and femur neck BMD (p<0.05). However, multivariate analysis did not show a significant association between femur and lumbar BMD and biochemical markers of bone turnover.

Conclusion

Long-term treatment with valproate combined with low-dose atypical antipsychotics may adversely affect BMD in premenopausal women with bipolar disorder. A prospective, controlled-study with a larger population is warranted, and assessment of BMD and bone metabolism should be taken into consideration in long-term therapy with valproate and atypical antipsychotics.     

Hybrid Surgery of Multilevel Cervical Degenerative Disc Disease : Review of Literature and Clinical Results

Objective

In the present study, we evaluated the effect, safety and radiological outcomes of cervical hybrid surgery (cervical disc prosthesis replacement at one level, and interbody fusion at the other level) on the multilevel cervical degenerative disc disease (DDD).

Methods

Fifty-one patients (mean age 46.7 years) with symptomatic multilevel cervical spondylosis were treated using hybrid surgery (HS). Clinical [neck disability index (NDI) and Visual Analogue Scale (VAS) score] and radiologic outcomes [range of motion (ROM) for cervical spine, adjacent segment and arthroplasty level] were evaluated at routine postoperative intervals of 1, 6, 12, 24 months. Review of other similar studies that examined the HS in multilevel cervical DDD was performed.

Results

Out of 51 patients, 41 patients received 2 level hybrid surgery and 10 patients received 3 level hybrid surgery. The NDI and VAS score were significantly decreased during the follow up periods (p<0.05). The cervical ROM was recovered at 6 and 12 month postoperatively and the mean ROM of inferior adjacent segment was significantly larger than that of superior adjacent segments after surgery. The ROM of the arthoplasty level was preserved well during the follow up periods. No surgical and device related complications were observed.

Conclusion

Hybrid surgery is a safe and effective alternative to fusion for the management of multilevel cervical spondylosis.     

Anterior Cervical Discectomy and Fusion Using a Stand-Alone Polyetheretherketone Cage Packed with Local Autobone : Assessment of Bone Fusion and Subsidence

Objective

It remains debatable whether cervical spine fusion cages should be filled with any kind of bone or bone substitute. Cortical and subcortical bone from the anterior and posterior osteophytes of the segment could be used to fill the cage. The purposes of the present study are to evaluate the clinical outcomes and radiological outcomes including bone fusion and subsidence that occurred after anterior cervical discectomy and fusion using a stand-alone cage packed with local autobone graft.

Methods

Thirty-one patients who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage packed with local autobone graft from July 2009 to december 2011 were enrolled in this study. Bone fusion was assessed by cervical plain radiographs and computed tomographic scan. Nonunion was evaluated according to the absence of bony bridge on computed tomographic scan. Subsidence was defined as a ≥2 mm decrease of the interbody height at the final follow-up compared to that measured at the immediate postoperative period.

Results

Subsidence was observed in 7 patients (22.6%). Of 7 patients with subsidence greater 2 mm, nonunion was developed in 3. Three patients with subsidence greater 2 mm were related with endplate damage during intraoperative endplate preparation. Solid bone fusion was achieved in 28 out of 31 patients (90.3%).

Conclusion

With proper patient selection and careful endplate preparation, anterior cervical discectomy and fusion (ACDF) using a stand-alone PEEK cage packed with local autobone graft could be a good alternative to the standard ACDF techniques with plating.     

Spinous Process-Splitting Hemilaminoplasty for Intradural and Extradural Lesions

Objective

To describe a novel spinous process-splitting hemilaminoplasty technique for the surgical treatment of intradural and posterior epidural lesions that promotes physiological restoration.

Methods

The spinous process was split, the area of the facet lamina junction was drilled, and en bloc hemilaminectomy was then performed. After removing intradural and posterior epidural lesions, we fitted the previously en bloc-removed bone to the pre-surgery same shape, and held it in place with non-absorbable sutures. Surgery was performed on 16 laminas from a total of nine patients between 2011 and 2014. Bony union of the reconstructed lamina was assessed using computed tomography (CT) at 6 months after surgery.

Results

Spinous process-slitting hemilaminoplasty was performed for intradural extramedullary tumors in eight patients and for ossification of the ligament flavum in one patient. Because we were able to visualize the margin of the ipsilateral and contralateral dura, we were able to secure space for removal of the lesion and closure of the dura. None of the cases showed spinal deformity or other complications. Bone fusion and maintenance of the spinal canal were found to be perfect on CT scans.

Conclusion

The spinous process-splitting hemilaminoplasty technique presented here was successful in creating sufficient space to remove intradural and posterior epidural lesions and to close the dura. Furthermore, we were able to maintain the physiological barrier and integrity after surgery because the posterior musculature and bone structures were restored.     

The Relationship between Increased Intervertebral Disc Height and Development of Postoperative Axial Neck Pain after Anterior Cervical Fusion

Objective

To evaluate the relationship between postoperative increase in intervertebral disc space height (IVH) and posterior axial neck in cases of degenerative cervical disease treated with anterior cervical discectomy and fusion (ACDF).

Methods

A total of 155 patients who underwent ACDF with more than 1 year follow up were included. Radiologically, IVH and interfacet distance (IFD) of the operated segment were measured preoperatively and postoperatively. We clinically evaluated neck and arm pains according to visual analogue scale (VAS) scores and assessed neck disability index (NDI) scores preoperatively, postoperatively, at 3 months, 6 months, and 1 year postoperatively. The relationship between radiological parameters, and clinical scores were analyzed using a regression analysis.

Results

The mean increase in IVH was 2.62 mm, and the mean increase in IFD was 0.67 mm. The VAS scores for neck pain preoperatively, postoperatively, and at 3 months, 6 months, 1 year postoperatively were 4.46, 2.11, 2.07, 1.95, and 1.29; those for arm pain were 5.89, 3.24, 3.20, 3.03, and 2.18. The NDI scores were improved from 18.52 to 7.47. No significant relationship was observed between the radiological evaluation results regarding the increase in intervertebral height or interfacet distance and clinical changes in VAS or NDI scores.

Conclusion

The increase in intervertebral space or interfacet distance by the insertion of a large graft material while performing ACDF for the treatment of degenerative cervical disease was not related with the change in VAS scores for neck and arm pains and NDI scores postoperatively and during the follow-up period.     

Atypical Anterior Spinal Artery Infarction due to Left Vertebral Artery Occlusion Presenting with Bilateral Hand Weakness

Background

Infarct of the anterior spinal artery is the most common subtype of spinal cord infarct, and is characterized by bilateral motor deficits with spinothalamic sensory deficits. We experienced a case with atypical anterior-spinal-artery infarct that presented with bilateral hand weakness but without sensory deficits.

Case Report

A 29-year-old man presented with sudden neck pain and bilateral weakness of the hands. Magnetic resonance imaging (MRI) of the brain did not reveal any lesion. His motor symptoms improved rapidly except for mild weakness in his left wrist and fingers. Magnetic resonance angiography showed proximal occlusion of the left vertebral artery; a spine MRI revealed left cervical cord infarction.

Conclusions

Bilateral or unilateral hand weakness can be the sole symptom of a cervical cord infarct.     

Surgical Outcomes after Traumatic Vertebral Fractures in Patients with Ankylosing Spondylitis

Objective

Ankylosing spondylitis is an inflammatory rheumatic disease mainly affecting the axial skeleton. The rigid spine may secondarily develop osteoporosis, further increasing the risk of spinal fracture. In this study, we reviewed fractures in patients with ankylosing spondylitis that had been clinically diagnosed to better define the mechanism of injury, associated neurological deficit, predisposing factors, and management strategies.

Methods

Between January 2003 and December 2013, 12 patients with 13 fractures with neurological complications were treated. Neuroimaging evaluation was obtained in all patients by using plain radiography, CT scan, and MR imaging. The ASIA Impairment Scale was used in order to evaluate the neurologic status of the patients. Management was based on the presence or absence of spinal instability.

Results

A total of 9 cervical and 4 thoracolumbar fractures were identified in a review of patients in whom ankylosing spondylitis had been diagnosed. Of these, 7 fractures were associated with a hyperextension mechanism. 10 cases resulted in a fracture by minor trauma. Posttraumatic neurological deficits were demonstrated in 11 cases and neurological improvement after surgery was observed in 5 of these cases.

Conclusions

Patients with ankylosing spondylitis are highly susceptible to spinal fracture and spinal cord injury even after only mild trauma. Initial CT or MR imaging of the whole spine is recommended even if the patient''s symptoms are mild. The patient should also have early surgical stabilization to correct spinal deformity and avoid worsening of the patient''s neurological status.     

Comparative Analysis of Cervical Lateral Mass Screw Insertion among Three Techniques in the Korean Population by Quantitative Measurements with Reformatted 2D CT Scan Images: Clinical Research

Objective

Our purpose of this study is to compare insertion angles and screw lengths from Roy-Camille, Magerl, and our designed method for cervical lateral mass screw fixation in the Korean population by quantitative measurement of reformatted two dimensional (2D) computed tomography (CT) images.

Methods

We selected thirty Korean patients who were evaluated with thin section CT scans and reconstruction program to obtain reformatted 2D-CT images of the transversal plane passing the cranio-caudal angle using three different techniques. We measured the minimum angle to avoid vertebral artery (VA) injury, the ideal angle and depth for bicortical screwing of cervical lateral mass. Morphometric measurements of the lateral masses from C3-C7 were also taken.

Results

In all three techniques, the mean safety angles from the VA were less than 8 degrees and the necessary depth of the screw was about 14 mm for safety to the VA and for the bicortical purchase. In our designed technique, the mean β angles of each level from C3 to C7 were 29.0, 29.8, 29.5, 26.3, and 23.9 degrees, respectively.

Conclusion

Results of this study and data from the literature indicate that differences may exist between the Korean and Western people in the length and angle for ideal lateral mass screw fixation. In addition, our technique needs further cadaveric and clinical study for safety and efficacy for being performed as alternative method for cervical lateral mass fixation.     

Clinical and Radiological Outcomes of Anterior Cervical Interbody Fusion Using Hydroxyapatite Spacer

Objective

This is retrospective study of clinical and radiological outcomes of anterior cervical fusion using Bongros-HA™ (BioAlpha, Seongnam, Korea) which is a type of synthetic hydroxyapatite (HA) spacer to evaluate the efficacy in its clinical application and usefulness as a reliable alternative to autograft bone.

Methods

Twenty-nine patients were enrolled in this study and 40 segments were involved. All patients were performed anterior cervical interbody fusion using HA spacer and plating system. Indications for surgery were radiculopathy caused by soft-disc herniation or spondylosis in 18 patients, spondylotic myelopathy in 1 patient, and spinal trauma in 10 patients. Cervical spine radiographs were obtained on postoperative 1day, 1week, and then at 1, 2, 6, and 12 months in all patients to evaluate intervertebral disc height, and the degrees of lordosis. Cervical computed tomography was done at postoperative 12 month in all patients to confirm the fusion status. The mean period of clinical follow-up was 17 months.

Results

Complete interbody fusion was achieved in 100% of patients. Preoperative kyphotic deformities were corrected in all cases after surgery. Intervertebral disc height was well maintained during follow up period. There were no cases of graft extrusion, graft deterioration and graft fracture.

Conclusion

HA spacer is very efficient in achieving cervical fusion, maintaining intervertebral disc height, and restoring lordosis. When combined with the placement of a cervical plate, immediate stability can be achieved and graft related complication can be prevented.     

Spinal Schwannoma; Analysis of 40 Cases

Objective

This study is to report our experience of 40 cases of spinal schwannoma.

Methods

From 1995 to 2006, medical records were retrospectively reviewed in 40 cases of spinal schwannoma.

Results

We treated 40 spinal schwannomas in 38 (22 male and 16 female) patients. The mean age was 50.2. Four cases were sited in the cervical spine, 11 cases in the thoracic spine, and 25 cases in the lumbar spine. Two patients showed recurrences. Thirty-eight cases were intradural-extramedullary type and 2 cases were extradural. Two cases (5%) including 1 recurred case had no postoperative motor improvement. Ninety-five percents of patients improved on postoperative motor grade.

Conclusion

Spinal schwannoma is mostly benign and extramedullary tumor. There were 2 recurred cases (5%) that had history of previous subtotal removal at first operation and had shown worse prognosis compared with the cases without recurrence. To reduce the recurrence of spinal schannoma, total excision of tumor mass should be done.     

Long-Term Clinical and Radiologic Outcomes of Minimally Invasive Posterior Cervical Foraminotomy

Objective

To report long-term clinical and radiological outcomes of minimally invasive posterior cervical foraminotomy (MI-PCF) performed in patients with unilateral single-level cervical radiculopathy.

Methods

Of forty-six patients who underwent MI-PCF for unilateral single-level radiculopathy between 2005 and 2013, 33 patients were included in the study, with a mean follow-up of 32.7 months. Patients were regularly followed for clinical and radiological assessment. Clinical outcome was measured by visual analogue scale (VAS) for the neck/shoulder and arm, and the neck disability index (NDI). Radiological outcome was measured by focal/global angulation and disc height index (DHI). Outcomes after MI-PCF were evaluated as changes of clinical and radiological parameters from the baseline. Mixed effect model with random patients'' effect was used to test for differences in the clinical and radiological parameters repeat measures.

Results

There were no complications and all patients had an uneventful recovery during the early postoperative period. VAS scores for neck/shoulder and arm improved significantly in the early postoperative period (3 months) and were maintained with time (p<0.001). NDI improved significantly post-operatively and tended to decrease gradually during the follow-up period (p<0.001). There were no statistically significant changes in focal and global angulation at follow-up. Percent DHIs of the upper adjacent or operated disc were maintained without significant changes with time. During the follow-up, same site recurrence was not noted and adjacent segment disease requiring additional surgery occurred in two patients (6%) on the contra-lateral side.

Conclusion

MI-PCF provides long-term pain relief and functional restoration, accompanied by good long-term radiological outcome.