[Comparison of effectiveness between laminoplasty and laminectomy decompression and fusion with internal fixation for cervical spondylotic myelopathy]

OBJECTIVE

To compare the clinical and radiographic outcomes between laminoplasty and laminectomy compression and fusion with internal fixation to treat cervical spondylotic myelopathy.

METHODS

Between September 2006 and September 2009, 143 cases of multilevel cervical myelopathy (the affected segments were more than 3) were treated by laminoplasty in 87 cases (group A) and by laminectomy decompression and fusion with lateral mass screw fixation in 56 cases (group B). There was no significant difference in gender, age, disease duration, pathological type, and affected segments between 2 groups (P > 0.05). The operation time, intraoperative blood loss, improvement of neurological function [Japanese Orthopaedic Association (JOA) 17 score], and the incidences of complications were observed; the cervical curvature index (CCI), range of motion (ROM), and symptoms of neck and shoulder pain [visual analogue scale (VAS) and neck disability index (NDI) scores] were recorded and compared.

RESULTS

There was no significant difference in operation time and intraoperative blood loss between 2 groups (P > 0.05). All patients were followed up 18-30 months (mean, 24 months). C5 nerve root palsy occurred in 4 cases (4.60%) of group A and in 5 cases (8.93%) of group B, showing no significant difference (chi2 = 0.475, P = 0.482). No complication of deep infection, pseudarthrosis, or screw loosening occurred. No closure of opened laminae was observed in group A; and no screw extrusion, breakage, or nerve injury was observed in group B. At last follow-up, neck axial symptoms appeared in 35 cases (40.23%) of group A and in 11 cases (19.64%) of group B, showing significant difference (chi2 = 6.612, P = 0.009). No significant difference was found in JOA score, CCI, ROM, or VAS scores between 2 groups at preoperation (P > 0.05); the JOA score, ROM, and VAS scores of groups A and B and CCI of group A at last follow-up were significantly improved when compared with preoperative ones (P < 0.05). No significant difference was found in the JOA score, improvement rate, and VAS score between 2 groups (P > 0.05); however, significant differences were found in ROM and CCI between 2 groups (P < 0.05). There were significant differences (P < 0.05) in pain intensity, lifting, work, reaction, driving, and total score between 2 groups at last follow-up.

CONCLUSION

Laminectomy decompression and fusion with internal fixation can effectively relieve pain, but it will greatly reduce the ROM; laminoplasty has less complications and satisfactory outcome. The two methods have similar effectiveness in the improvement of neurological function.

[Clinical application of centerpiece titanium plate fixation in open door laminoplasty]

OBJECTIVE

To explore the clinical application of Centerpiece titanium plate fixation in open door laminoplasty.

METHODS

From January 2009 to December 2010,25 patients with cervical spinal stenosis were treated by open door laminoplasty with Centerpiece titanium plate fixation. There were 16 males and 9 females,with a mean age of (57.2 +/- 6.7) years (ranged, 44 to75 years). There were multilevel cervical myelopathy in 8 cases, posterior longitudinal ligament ossification in 12 cases and congenital cervical spinal stenosis in 5 cases. According to Japanese Orthopedic Association (JOA) score to evaluate nerve function and calculate improvement rate. X-ray and CT were used to evaluate postoperative spinal canal enlargement and bone fusion at the hinge side. The sagittal diameter of C5 spinal canal on the lateral X-ray was measured before operation and 6 months after operation respectively, and the expansion rate of spinal canal was calculated [(postoperative sagittal diameter-preoperative sagittal diameter)/(preoperative sagittal diameter) x 100%].

RESULTS

The operative time and intraoperative blood loss were respectively (165.5 +/- 35.6) min and (325.0 +/- 75.1) ml. All patients were followed up from 6 to 18 months with an average of (7.3 +/- 3.8) months. The JOA score increased from 9.3 +/- 1.1 before operation to 14.7 +/- 2.1 at 6 months after operation (t = 4.12, P < 0.05), and the improvement rate was (64.5 +/- 10.2)%. Radiographic data showed spinal canal enlarged perfectly, bone fusion at hinge side and no cervical spinal stenosis was found. The sagittal diameter of C5 spinal canal improved from (9.0 +/- 1.5) mm before operation to (14.3 +/- 2.0) mm at 6 months after operation (t = 7.61, P < 0.05), and the expansion rate was (67.6 +/- 11.8)%.

CONCLUSION

Clinical application of Centerpiece titanium plate fixation in open door laminoplasty is safe and effective. While vertebral plate is elevated to obtain instantly stability, at the same time, the integrity of spinal canal is also recovered.

[Clinical application of lower cervical spinous process laminar screw technique in open door laminoplasty]

OBJECTIVE

To investigate the clinical outcomes of lower cervical spinous process laminar screw technique in open door laminoplasty.

METHODS

From February 2005 to June 2010,12 patients with cervical myelopathy were treated with open door laminoplasty by lower cervical spinous process laminar screw technique. There was intervertebral disc herniation with degenerative stenosis in 5 patients, ossification of posterior longitudinal ligament with osteophyte in 6 patients, cervical traumatic instability with spinal cord injuries in 1 patient. Nerve function, complications, and the cervical canal to body ratio (CBR), range of motion (ROM) and the anteroposterior serial alignment were observed by Japanese Orthopedic Association (JOA) score, X-ray, CT and MRI.

RESULTS

The surgical time was from 1.5 to 2 h with an average of 110 min; blood loss during operation was from 450 to 800 ml with an average of 580 ml. Postoperative complication occurred in 1 case with upper limb pain and 1 case with cerebrospinal fluid leakage. All patients were followed up from 1 to 2 years with an average of 21.8 months. JOA score improved from preoperative 9.5 +/- 1.8 to postoperative 13.6 +/- 2.4 (P < 0.01). X-ray, CT, MRI showed CBR increased obviously (P < 0.01); ROM on flexion-extension and cervical lordosis decreased respectively from (40.0 +/- 10.0) degrees and (65.0 +/- 12.0)% before operation to (15.0 +/- 5.0) degrees and (42.0 +/- 8.0) % at the final follow-up (P < 0.01).

CONCLUSION

Lower cervical spinous process laminar screw technique in open door laminoplasty for cervical syndrome is safe and can obtain satisfactory effects, has strong internal fixation and reduce the risk of re-closure.

Lumbopelvic fixation for multiplanar sacral fractures with spinopelvic instability

Sacral fractures with both transverse and bilateral vertical fracture components are by definition multiplanar fractures, and often present with spinopelvic instability and cauda equina deficits. The treatment is challenging. Between 2006 and 2009, we treated nine such patients at our trauma centre. There were six men and three women, with a mean age of 32.2 years. Preoperative neurologic deficits were noted in seven patients; four patients had complete cauda equina paralysis, and three patients had incomplete cauda equina syndrome. All patients were treated using lumbopelvic instrumented fixation without other devices for their multiplanar sacral fractures. Six patients who had neurological deficits and sacral canal compression underwent decompression laminectomy. The mean postoperative follow-up time was 21.7 months (range, 14-32 months). All fractures went on to union without loss of reduction or hardware failure. The mean Gibbons score improved from 3.5 preoperatively to 2.3 postoperatively among the patients who underwent decompression laminectomy. Eight out of nine patients had fair or better results based on radiographic criteria and the Majeed pelvic fracture outcome score. Our experience suggests lumbopelvic fixation can be used for the treatment of multiplanar sacral fractures with spinopelvic instability with a low rate of complications. Neurologic improvement can be expected, but whether surgical decompression results in substantially better neurologic recovery than conservative treatment remains uncertain.

[Analysis of axial symptoms after indirect decompression for ossification of the posterior longitudinal ligament of the cervical spine]

OBJECTIVE

To study the etiology and clinical significance of axial symptoms after posterior operative procedures for ossification of the posterior longitudinal ligament (OPLL).

METHODS

From February 2005 to February 2010, 76 patients with OPLL treated were retrospectively experienced. There were 34 male and 42 female with average of 52.1 years (range from 37 to 74 years), the average duration of the disease was 32.1 months (range from 11 to 56 months). Nineteen patients underwent traditional laminectomy in group A, 33 patients received open-door laminoplasty in group B and 24 patients underwent lateral mass screw fixation in group C. All patients underwent X-ray examination pre- and post operative, computed tomography were used for diagnosis of OPLL, the recovery rate was calculated using pre- and postoperative Japanese Orthopedic Association (JOA) scores for each patient. Pre- and postoperative cervical curvature index and axial symptoms were measured and compared. χ(2) test and SNK test were used as statistical methods.

RESULTS

All patients were followed up for 14 - 35 months, average (21 ± 5) months. Loss of cervical curvature index was 4.2% ± 1.7% in group A, 2.9% ± 2.2% in group B and 2.3% ± 1.9% in group C. The difference was significant in loss of cervical curvature indice between group A and B (q = 2.94, P < 0.01), group A and C (q = 4.23, P < 0.01). The average JOA recovery rate was 58.3% for group A, 64.3% for group B and 66.7% for group C. There was no significant difference in JOA recovery rate among the three groups (P > 0.05). The rate of early evident axial symptoms was 7/19 in group A, 30.3% in group B and 33.3% in group C and the difference was not statistically significant (P > 0.05). The incidence of late evident axial symptoms was 5/19 in group A, 12.1% in group B and 8.3% in group C, the difference was not significant between group B and C (χ(2) = 13.762, P < 0.01), but of statistical difference between group A and B(χ(2) = 6.368, P < 0.01), group A and C (χ(2) = 11.481, P < 0.01). No kyphotic deformity in the group A, no "Close Door" phenomenon in group B and no internal failure in group C.

CONCLUSION

The incidence of early axial symptoms are of no significant difference among the three groups, but late axial symptoms are higher in the laminectomy than other groups, which may be associated with loss of cervical lordosis.

[Biomechanical research on different pairs of lumbar laminectomy with finite element analysis]

The finite element model of the intact lumbar spine (L1-L5) was set up to study the biomechanical changes of three different pairs of the lumbar laminectomy. The three-dimensional finite elements model of L1-L5 vertebrae structure was constructed by the combination of self-compiled software and Hyper Mesh. The finite element model was compared with the experimental data in vitro. The finite element model was modified of stenosis at L3-L4 and L4-L5 with the same boundary conditions and physical loads to study the motion and loading in the annulus changes at the surgical site as a result of surgical alteration. The study suggested that the removal of posterior lumbar spinal elements for the treatment of stenosis at L3-L4 and L4-L5 produced a graded increase in motion at the surgical site, with the greatest changes occurring in flexion-extension and axial rotation and that during lateral bending the amount of resection was only slightly affected. The data showed that for flexion-extension and axial rotation the increases in motion were correlated to the extent of posterior element removal. It is necessary to retain the greatest degree of posterior lumbar structures in thorough decompression, which can further reduce the postoperative intervertebral disc, facet degeneration.

[Short-term effectiveness of interlaminar lumbar instrumented fusion through a small incision for lumbar spinal stenosis]

OBJECTIVE

To evaluate the short-term effectiveness of local laminectomy and interlaminar lumbar instrumented fusion (ILIF) through a small incision for lumbar spinal stenosis.

METHODS

Between November 2009 and January 2011, 16 patients with lumbar spinal stenosis were treated by local laminectomy and ILIF through a small incision. There were 7 males and 9 females with an average age of 52.8 years (range, 49-67 years). Sixteen patients had lumbar degenerative stenosis with an average disease duration of 4 years and 7 months (range, 2 years-9 years and 4 months). Four cases complicated by lateral recessus stenosis, 3 by lumbar disc herniation. Involved segments included L3,4 in 2 cases, L4,5 in 4 cases, L5, S1 in 4 cases, L3,4 and L4,5 (double segments) in 2 cases, L4,5 and L5, S1 (double segments) in 4 cases. The effectiveness was evaluated with the pre- and post-operative Visual Analogue Scale (VAS) scores, Oswestry Disability Index (ODI). The cross-sectional areas of spinal canal were measured by CT scanning and were compared between pre- and post-operation.

RESULTS

The average operative time was 47 minutes (range, 35-80 minutes); the average blood loss was 145 mL (range, 120-350 mL); and the average hospitalization days were 7.8 days (range, 4-15 days). Cerebrospinal fluid leakage occurred in 1 case, and healing of incisions by first intention was achieved in the others. The patients were followed up 12-22 months (mean, 14.8 months). CT scanning showed interspinous fusion in 14 cases and possible fusion in 2 cases after operation, with an average fusion time of 4.6 months (range, 3-10 months). The postoperative VAS score, ODI, and cross-sectional area were significantly improved when compared with preoperative values (P < 0.05).

CONCLUSION

The ILIF can promote fusion between spinous processes, provide spine stabilization, and protect the spinal cord. The procedure has small incision, simple method of fixation and fusion.

C2 lamina reconstruction using locking miniplate for the intradural tumor of the craniocervical junction (two case reports)

OBJECTIVE

To describe a technique for C2 lamina reconstruction using locking miniplates for the extirpation of spinal tumors in the craniocervical junction. Many spinal surgery cases in which lamina reconstructions have been performed using non-locking miniplates have been reported. However, there is only one report of the use of locking miniplates for lamina reconstruction in spinal tumor cases.

METHODS

We performed C2 lamina reconstructions using locking miniplates in a patient with a spinal tumor and another with a cystic lesion. The clinical and radiologic features of both cases are reported, and the surgical technique is described.

RESULTS

A 62-year-old female and a 30-year-old male were diagnosed with meningioma and a neurenteric cyst, respectively, in the craniocervical junction. Extirpation of these lesions was performed in combination with C2 lamina reconstruction and reattachment of the paraspinous muscle to the C2 spinous process. A follow-up examination at 1 year postoperatively demonstrated no significant change in the sagittal alignment of the cervical spine and a good postoperative course in both cases. Bony fusion was detected in both cases, and no implant failure occurred in either case.

CONCLUSIONS

This procedure results in rigid fixation of the reimplanted C2 lamina and helps to restore the paraspinous muscles. For these reasons, it appears to be a useful surgical procedure for spinal tumors requiring C2 laminectomy and does not cause postoperative kyphosis of the cervical spine.

Hemi-semi laminectomy approach for the microsurgical treatment of spinal schwannomas

OBJECTIVE

To evaluate the safety and efficiency of hemi-semi laminectomy approach for the microsurgical treatment of spinal schwannomas.

METHODS

A total of 22 patients underwent hemi-semi laminectomy for the microsurgical removal of spinal schwannomas during a period of 2009 and 2011 in Affiliated Hospital of Nantong University. We retrospectively analyzed the clinical outcomes of these patients.

RESULTS

Of them, 5 cases were diagnosed with cervical schwannomas, 9 with thoracic schwannomas, and 8 with lumbar schwannomas. All the tumors including two dumbbell schwannomas were totally removed without major complications. Postoperatively, all patients were followed up from 6 to 36 months. The symptoms and signs were obviously improved, and no tumor recurrence or spinal deformity occurred.

CONCLUSION

Hemi-semi laminectomy is a safe and effective method for resection of spinal schwannomas.

[Surgery tactics for ossification of ligamentum flavum associated with dural ossification in the thoracic spine]

OBJECTIVE

To investigate the surgery tactics for ossification of ligamentum flavum (OLF) associated with dural ossification (DO) in the thoracic spine and the clinical outcome.

METHODS

Between June 2006 and December 2009, 98 patients with thoracic spinal stenosis secondary to OLF were treated, and DO was found in 18 cases during operation. There were 11 males and 7 females with a mean age of 58 years (range, 46-73 years). The disease duration ranged from 5 to 48 months (mean, 20 months). All patients underwent surgical decompression because of recent neurological aggravation. Both DO and OLF were resected with octagonal decompression by dissecting pedicle flavum tunnel. The Japanese Orthopaedic Association (JOA) score, modified Oswestry Disability Index (ODI), and the Cobb angle were used to evaluate the effectiveness.

RESULTS

The initial symptoms were significantly alleviated postoperatively. All patients had transient cerebrospinal fluid (CSF) leakage postoperatively, the CSF leakage disappeared after 8-10 days of conservative treatment. All the incisions healed by first intention. There was no complication of neurologic function deterioration, meningitis, wound infection, or spinocutaneous fistula. Eighteen patients were followed up 20-60 months (mean, 49 months). No recurrence of spinal cord compression symptoms, or neurologic function deterioration was observed at last follow-up. The JOA scores and effectiveness and modified ODI scores were significantly improved after 1 month and 12 months of operation when compared with preoperative scores (P < 0.05). The Cobb angles of kyphosis of the involved vertebrae were (6.7 +/- 1.6) degrees before operation and (8.0 +/- 1.2) degrees after 12 months of operation, showing significant difference (t = 4.000, P = 0.001). Postoperative T2-weighted axial MRI, sagittal MRI scan, and short T1 inversion recovery MRI showed that compressed deformity of the spinal cord returned to normal.

CONCLUSION

The surgery tactics for thoracic spinal stenosis secondary to the OLF with DO is safe, and no patching dura mater tears is effective.

[Comparison of two techniques in hemivertebra resection: anterior- posterior approach versus posterior approach]

OBJECTIVE

To Compare the two techniques in the treatment of congenital kypho-scoliosis caused by fully-segmented hemivertebra.

METHODS

44 consecutive cases, 21 males and 23 females. The average age at surgery was 11.4 years ranging from 2 to 17 years, 20 patients underwent one-stage anterior and posterior hemivertebra resection and instrumentation. 24 patients underwent one-stage posterior hemivertebra resection and instrumentation. Long cassette standing radiographs were taken before and after surgery and at the final follow-up. The apical translation, the Cobb's angle in the coronal and sagittal plane were measured and analyzed. The medical records were reviewed and the complications were recorded.

RESULTS

The average follow-up was 39.2 months ranging from 24 to 72 months. The 2 groups did not demonstrate any significant differences in gender, age at surgery, preoperative and postoperative Cobb angle, blood loss, or fusion segments (all P > 0.05). However, the anterior and posterior group demonstrated a less curve flexibility and longer operative time compared with the posterior groups (all P < 0.05).

COMPLICATIONS

the anterior and posterior group included pedical cutting in 1 case, lumber curve decompensation in 1 case and crankshaft phenomenon in 2 cases. The posterior group included pedical cutting in 1 case and length of instrumentation in 1 case.

CONCLUSIONS

Two techniques are safe and effective procedure for the congenital kypho-scoliosis. Anterior and posterior hemivertebra resection is indicated to rigid deformity, and anterior epiphysiodesis is needed to avoid crankshaft phenomenon for patients at an earlier skeletal age. Posterior hemivertebra resection can save operation time and is less invasive compared with anterior-posterior approach.

[Research progress of complications of expansive laminoplasty]

OBJECTIVE

To review the progress in the research of complications after expansive laminoplasty such as axial symptom, kyphotic deformity, and segmental motor paralysis.

METHODS

Recent articles about complications after expansive laminoplasty were reviewed, and comprehensive analysis was done.

RESULTS

The pathogenesis of axial symptom, kyphotic deformity, and segmental motor paralysis has not yet fully been understood, but has brought new finding, such as the importance of the spinous process-ligament-muscle complex, C5 palsy theory, and the involvement of the spinal cord mechanism.

CONCLUSION

The pathogenesis of axial symptom, kyphotic deformity, and segmental motor paralysis should be further investigated to prevent and treat the complications.

Resection of a large spinal intradural ependymoma using a limited unilateral laminectomy approach in the lumbosacral region

Ependymomas are the most common gliomas of the lower spinal cord, conus medullaris and filum terminale. Although there are several surgical modalities indicated in the removal of spinal tumors, total laminectomy is the conventional method used. However, surgical complications, such as spinal deformities and instability are more common with this approach compared to limited unilateral hemilaminectomy. To present the clinical and radiologic results of patient with a large spinal intradural ependymoma via a limited posterior unilateral laminectomy approach in the lumbosacral region. The aim of this study was to present a modified duramater incisions and surgical positions setup, and discussed the major controversies in treatment in the literature. This article reports the surgical resection of a lumbosacrally localized ependymoma in a 25-year-old male patient using unilateral laminectomy at the L4 to S3 levels. The tumor was removed with any difficulty in reaching to contralateral side. A follow-up lumbar magnetic resonance imaging scan with and without contrast performed 18 months postoperatively showed no residual or recurrent tumor lesions. This procedure may be more difficult than the conventional total laminectomy as suturing of the duramater. However, modified duramater incisions and setup of microscope-operating table provides best facilitates to surgery manipulation. Besides, unilateral limited laminectomy protected the posterior supporting elements. In order to reduce the postoperative complications and minimize the destruction of tissue, unilateral limited hemilaminectomy is recommended for the removal of intradural tumors. This technique facilitates the return of the patient to ordinary life.

Operative results of laminoplasty in multilevel cervical spondylosis with myelopathy: a comparison of two surgical techniques

OBJECTIVE

To compare the surgical results of two unilateral open-door cervical laminoplasty in patients with multilevel cervical spondylosis with myelopathy (CSM) or ossification of posterior longitudinal ligament (OPLL) in Songklanagarind Hospital.

MATERIAL AND METHOD

This was a cohort study between January 2007 and December 2009. Thirty-eight patients were categorized into two groups of two periods. The Itoh and Tsuji laminoplasty technique (spinous process laminar elevation spacer) was performed in the first group. In the second group, the modified Hirabayashi laminoplasty technique (secured suture to elevated laminar with facet joint) was performed. All patients were followed up for at least 18 months. Demographic data, physical examination, postoperative Nurick score, JOA score, and recovery rate were collected.

RESULTS

All patients experienced improvement of neurological symptoms, Nurick score, JOA score, and recovery rate. There were no postoperative complications such as C5 nerve root palsy or neck pain. There were no statistically significant differences in all outcomes between the two surgical laminoplasty techniques. However the modified Hirabayashi laminoplasty technique had significantly less operative blood loss (p = 0.005) and a shorter operative time than the Itoh and Tsuji technique.

CONCLUSION

There were no statistically significant differences in the surgical results of either technique, while the modified Hirabayashi technique had less operative time and blood loss. This suggests that the modified Hirabayashi technique is the technique of choice.

Extensive laminectomy for the treatment of ossification of the posterior longitudinal ligament in the cervical spine

OBJECTIVE

To introduce the surgical strategy of extensive laminectomy (with inner 1/4 facet joint resection to expose the origin of the nerve root) and to discuss its benefit for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL) with myelopathy.

METHODS

From January 1998 to December 2005, 82 patients with cervical OPLL underwent extensive laminectomy. We assessed neurological function using the Japanese Orthopedic Association (JOA) scoring system, neck/shoulder pain using a visual analogue scale (VAS), and cervical curvature index (CCI) by the Ishihara method; the expansion degree and the drift-back distance of the spinal cord was calculated using the MRI image.

RESULTS

The mean duration of follow-up was 41.6 months. The postoperative JOA score suggested that neurological function improved significantly with a recovery rate of 64%. The incidence rate of transient palsy of the C5 nerve root, which occurred in only 2 patients who recovered to useful function over 2 weeks, was 2.4%. The postoperative VAS score suggested that the pain in the neck/shoulder was mild. Although the postoperative CCI was small, there was no correlation with the length of follow-up period. The increased cross-sectional area of the dural sac at the level of maximum compression together with the significant drift-back distance of the spinal cord suggested that decompression was complete.

CONCLUSION

Extensive laminectomy is effective in treating cervical OPLL, with mild cervical/shoulder pain, low rate of C5 nerve root palsy, and no recurrence of spinal cord compression symptoms.

Diagnosis and management of metastatic cervical spine tumors

The bony spine is overall the third most common site for distant cancer metastasis, with the cervical spine involved in approximately 8 to 20% of metastatic spine disease cases. Diagnosis and management of metastatic spine disease requires disease categorization into the compartment involved, pathology of the lesion, and anatomic region involved. The diagnostic approach should commence with careful physical examination, and the workup should include plain radiographs, magnetic resonance imaging, computed tomography, and bone scintigraphy. Management ranges from palliative nonoperative to aggressive surgical treatment. Optimal management requires proper patient selection to individualize the most appropriate treatment modality.

Posterior surgery for cervical myelopathy: indications, techniques, and outcomes

This article details the controversies associated with the different treatment strategies in patients with cervical spondylotic myelopathy. The natural history, incidence, pathophysiology, physical examination, and imaging findings are discussed followed by the indications, techniques, and outcomes of patients treated with posterior cervical decompression via decompressive laminectomy, laminectomy and instrumented fusion, and laminoplasty.

[Clinical application of titanium miniplate in cervical expansive open-door laminoplasty]

OBJECTIVE

To evaluate the clinical effects of titanium miniplate in cervical expansive open-door laminoplasty in treating cervical spondylosis.

METHODS

From February 2009 to April 2011, 16 patients underwent expansive open-door laminoplasty by titanium miniplate fixation were classified as group A; 18 patients with conventional unilaterally open-door laminoplasty from March 2007 to January 2009 were served as control (group B). The operative time, blood loss during the operations, JOA score of the 6 months after operation, the incidence of axial symptom, curvature of cervical vertebrae were compared respectively between the two groups.

RESULTS

Operative time, blood loss, improvement rate of JOA in group A were respectively (122.0 +/- 26.8) min, (153.0 +/- 46.7) ml, (59.4 +/- 11.6)%; and in group B were (119.0 +/- 28.6) min, (151.0 +/- 50.4) ml, (58.7 +/- 12.7)%. Those showed no significant difference between two groups (P > 0.05). Three cases (18.75%) occurred obviously axial symptom in group A and six cases (33.33%) occurred in group B, there was significant difference in the incidence of axial symptom between two groups (P < 0.01). Preoperative and postoperative curvature of cervical vertebrae in group A was (17.9 +/- 5.2) degrees and (18.2 +/- 4.8) degrees, without significant difference; in group B, postoperative curvature of cervical vertebrae decreased obviously than the preoperative [(16.3 +/- 5.9) degrees vs (18.1 +/- 6.3) degrees] (P < 0.05).

CONCLUSION

Both surgical protocols are effective on preventing reclose of opened laminae, moreover the modified laminoplasty is advanced on reducing the occurrence of axial symptoms and loss of cervical curvature.

[Effectiveness analysis of Vertex rod-screw system in cervical expansive open-door laminoplasty]

OBJECTIVE

To evaluate the clinical application value and short-term results of Vertex rod-screw system in cervical expansive open-door laminoplasty.

METHODS

Between February 2008 and January 2010, 28 patients underwent Vertex rod-screw system fixation in cervical expansive open-door laminoplasty, including 15 cases of cervical spondylotic myelopathy, 5 cases of ossification of posterior longitudinal ligament, and 8 cases of cervical spondylosis with spinal stenosis. There were 16 males and 12 females, aged 42-77 years (mean, 61.3 years). The disease duration was 2 months to 11 years. The decompression range of cervical spine was from C3 to C7. The operation time, blood loss, Japanese Orthopedic Association (JOA) scores, and incidence of axial symptom were recorded. Pre- and postoperative curvature angles were demonstrated by the cross angle between posterior vertebral body margins of C2 and C7 on cervical X-ray films. The angle of the opened laminae was measured on CT scan at last follow-up.

RESULTS

The operation time was (142.5 +/- 22.8) minutes, and the blood loss was (288.2 +/- 55.1) mL. All incisions healed by first intention. All patients were followed up 14-25 months (mean, 22 months). CT showed that no reclosed open-laminae or loosening and breakage of rod-screw system occurred at 1 week and 1 year after operation. The axial bony fusion rate was 89.3% (25/28). The improvement rate of JOA scores at 1 week after operation (29.5% +/- 15.0%) was significantly smaller than that at 1 year after operation (64.9% +/- 28.1%) (t = 0.810, P = 0.000). No case presented with C5 nerve root palsy. The cervical curvature angle was (24.29 +/- 5.04) degrees before operation, was (23.89 +/- 3.57) degrees at 1 week, and was (23.41 +/- 3.35) degrees at 1 year after operation, showing no significant difference between pre- and postoperative angles (P > 0.05). The angle of the opened laminae was (27.90 +/- 4.74) degrees at 1 week after operation, and was (28.07 +/- 4.21) degrees at 1 year after operation, showing no significant difference (P > 0.05).

CONCLUSION

Vertex rod-screw system in cervical expansive open-door laminoplasty is effective in preventing reclosed open-laminae, which can reduce the loss of cervical curvature angle.

Mini-open versus open decompression and fusion for lumbar degenerative spondylolisthesis with stenosis

The outcome of less invasive surgical techniques in comparison to traditional surgical techniques has been the source of debate. In this retrospective study, 51 patients who had undergone posterior lumbar fusion along with bilateral decompression were enrolled. Twenty-one patients underwent fusion using a standard, midline open technique (open group) and 30 patients underwent fusion using a mini-open technique, with a small, central incision for the decompression and bilateral paramedian incisions for the posterolateral fusion and placement of cannulated pedicle screws (mini-open group). Surgical variables were compared between the 2 groups. Patients in both groups experienced significant improvements in leg pain at 12 months, with a reduction in visual analog scale scores from 7.6 to 2.4 in the open group, and 7.8 to 2.3 in the mini-open group. There were no statistical differences between the groups in the magnitude of improvement of either the visual analog scale or Oswestry Disability Index scores. Operative times, blood loss, and length of hospitalization failed to show statistically significant differences between the groups, although there was a trend toward less blood loss and shorter hospitalization in the mini-open group. Fusion results and complications were similar between the 2 groups. Both techniques resulted in similarly statistically significant improvements in pain and clinical function.

Perioperative administration of gabapentin 1,200 mg day-1 and pregabalin 300 mg day-1 for pain following lumbar laminectomy and discectomy: a randomised, double-blinded, placebo-controlled study

INTRODUCTION

Gabapentin and pregabalin have been compared in studies conducted on management of neuropathic and postoperative pain. In neuropathic pain studies, the analgesic effects of the two drugs were compared, and pregabalin has been found to be more potent. However, in postoperative pain studies, the effects of each drug were examined separately. This study compared the analgesic effects of pregabalin (300 mg day-1), gabapentin (1,200 mg day-1) and a placebo in managing postoperative pain following laminectomy and discectomy.

METHODS

90 patients were randomly assigned to three groups (pregabalin, gabapentin and placebo) of 30 patients each. Pregabalin 150 mg, gabapentin 600 mg and a placebo were administered every 12 hours, two times pre- and post surgery. Study data collected included morphine consumption, Visual Analogue Scale records, preoperative anxiety, patient satisfaction, adverse effects and observation notes.

RESULTS

In the gabapentin and pregabalin groups, overall morphine consumption, preoperative anxiety, pruritus, postoperative shivering were significantly lower (p-value less than 0.05 for all), and patient satisfaction was significantly higher than those in the placebo group (p-value less than 0.05).

CONCLUSION

This study showed that both pregabalin 300 mg day-1 and gabapentin 1,200 mg day-1 have more analgesic, anxiolytic and opioid-sparing effects, higher patient satisfaction and are more effective for preventing postoperative shivering than the placebo following lumbar laminectomy and discectomy. The findings revealed that pregabalin 300 mg day-1 had equivalent analgesic, adverse and opioid-sparing effects and patient satisfaction as gabapentin 1,200 mg day-1.

Rates of lead migration and stimulation loss in spinal cord stimulation: a retrospective comparison of laminotomy versus percutaneous implantation

BACKGROUND

Neuromodulation has been used to treat neuropathic pain. Leads have been implanted using laminotomy or percutaneous approaches. Laminotomy implantation has been shown to be superior in terms of lead migration when compared to percutaneous implantation. Lead migration has been reported as high as 68% with the percutaneous approach. Because of this, newer anchors have been developed but not tested in vivo.

OBJECTIVES

This study tests the hypothesis that newer anchoring systems have improved lead migration rates for percutaneous leads relative to laminotomy leads to the point of parity. This study also analyzed if factors such as laterality of symptoms, lead type, level of implant and diagnosis affect migration rates.

STUDY DESIGN

Neurostimulators implanted in the thoracolumbar spine at Henry Ford Hospital between 2006 and 2008 were reviewed for the following: age, sex, diagnosis, lead type, and implant level. Implants were reviewed for the following: age, sex, diagnosis, lead type, implant level, implant method, symptom laterality, loss of stimulation, radiographic lead migration, and time to loss. Loss of capture and lead migration in the laminotomy and percutaneous groups were compared using Fisher's exact test. Variables within each group included: lead type, level of implantation, location of symptoms, and diagnosis. They were compared using Fisher's exact test. Time to loss of stimulation was compared using the Wilcoxon 2-sample test.

SETTING

Pain Clinic, Henry Ford Hospital, Detroit, MI.

RESULTS

Laminotomies were performed by a single neurosurgeon and percutaneous implants were performed by a single pain medicine specialist. Percutaneous leads were anchored using Titan (Medtronic Corporation, Minneapolis, MN) anchors. Loss of capture was 24% laminotomy and 23% percutaneous with no significant difference between the 2 groups (P = 0.787). Radiographic evidence of migration was 13.63% percutaneous and 12.67% laminotomy with no significant difference (P = 0.999). The average days to loss of stimulation for the laminotomy versus percutaneous were as follows: 124.82 and 323.6 which were not statistically significant. There was no statistical difference in the days to loss of capture between the groups (P = 0.060). There was no significant difference between unilateral or bilateral symptoms in loss of capture within either group (P = 0.263, P = 0.326). There was not enough data to do comparisons by diagnosis. Comparisons of loss of capture based on electrode type was not significant in either group (P = 0.687, P = 0.371). The effect of the spinal level on the lack of recapture rates was not able to be calculated due to the number of levels.

LIMITATIONS

Retrospective study.

CONCLUSION

Rates of stimulation loss and radiographic lead migration are similar for both laminotomy and percutaneous implantation. Time to loss of stimulation was not statistically different in either group, although there was a trend toward laminotomy leads migrating earlier. Lead type and laterality of symptoms do not affect lead migration rates. The effect of the level of implant and diagnosis was indeterminate.

[Clinical analysis of C5 nerve root palsy in hinge side and different angles in lamina open-door after expansion of open-door cervical laminoplasty]

OBJECTIVE

To evaluate and compare the relation of the clinical results of expansion of open-door cervical laminoplasty (EOLP), C5 nerve root palsy in hinge side, and reclose of the opened laminae with different angles in lamina open-door.

METHODS

Between July 2006 and January 2009, 198 patients with cervical myelopathy were treated by EOLP. According to different opening angles which were measured by CT scan after operation, the patients were divided into group A (> 30 degrees, 76 patients including 44 males and 32 females) and group B (15-30 degrees, 122 patients including 71 males and 51 females). There was no significant difference in gender, age, disease duration, and segmental lesions between 2 groups (P > 0.05). The Japanese Orthopaedic Association (IOA) score before and after operation was used for neurological assessment and improvement rate, and the postoperative C5 nerve root palsy and reclose of the opened laminae were recorded.

RESULTS

There was no significant difference in operation time, bleeding volume, and hospitalization days between 2 groups (P > 0.05). After 3 weeks of operation, C5 nerve root palsy in the hinge side occurred in 7 patients (9.2%) of group A, and in 2 patients (1.6%) of group B, were restored after symptomatic treatment, showing significant difference between 2 groups (chi2 = 4.568, P = 0.033). All patients were followed up 24 to 48 months. Between group A and group B, no significant difference was found in JOA improvement rate at 24 months after operation (P > 0.05), and in JOA score at preoperation and at 24 months after operation (P > 0.05), but JOA score was significantly improved at 24 months after operation when compared with preoperative score in the same group (P < 0.05). The function of limb lifting restored in 9 cases of C5 nerve root palsy at 24 months after operation; CT examination revealed that no reclose occured in group A and reclose occurred in 4 cases (3.3%) of group B, but no persistent symptoms or worsen situation were found during follow-up.

CONCLUSION

Different angles in lamina open-door have the same clinical result; C5 nerve palsy has good prognosis. The opening angle between 15 degrees and 30 degrees will reduce the incidence of C5 nerve root palsy in the hinge side, but the open side should be firmly fixed to prevent further reclose of the opened laminae.

Intramedullary spinal cord metastasis from papillary thyroid carcinoma

BACKGROUND

Intramedullary spinal cord metastasis (ISCM) is an uncommon complication of malignancy. ISCM from thyroid cancer is extremely rare, only a few cases had been reported and most were found at autopsy. Here we report a patient with progressive lower leg weakness due to ISCM from papillary thyroid carcinoma who had a good response to surgery.

PATIENT FINDINGS

A 44-year-old woman presented with bilateral lower leg pain in December 2009. She underwent a total thyroidectomy in 1997 because of large mass in the right neck, which was diagnosed as papillary thyroid carcinoma. She had repeated I-131 therapies, but brain metastasis developed in 2002. When she was admitted, lower leg pain and weakness progressed rapidly. We performed magnetic resonance of the spine and whole-body fluorodeoxyglucose (FDG)-positron emission tomography scan, which demonstrated a 2×6 cm intramedullary mass enhanced by gadolinium with FDG-uptake. She underwent emergency laminotomy with subtotal tumor removal. Pathology revealed metastatic papillary thyroid carcinoma. After the emergent operation she could walk without help.

CONCLUSION

We report a patient with ISCM from papillary thyroid carcinoma. Surgical resection should be considered in patients with ISCM from papillary thyroid carcinoma. Early diagnosis and surgical resection could improve the quality of life and the neurologic deficits.

Evaluation of tenoxicam on prevention of arachnoiditis in rat laminectomy model

Post laminectomy arachnoiditis has been shown by experiments with rats and post operative radiological imaging in humans. The purpose of this experimental study was to determine the efficacy of tenoxicam in preventing arachnoiditis in rats. Twenty-four Wistar rats were divided into two groups, and L3 laminectomy was performed. In the tenoxicam group, 0.5 mg/kg tenoxicam was applied intraperitoneally. Normal saline was applied intraperitoneally in the control group. Later, the rats were killed at weeks 3 and 6, and the laminectomy sites were evaluated pathologically for arachnoiditis. The results showed that 6 weeks after surgery, the tenoxicam group showed lowest arachnoiditis grades. However, statistically significant difference was not found in arachnoiditis between the control group and the tenoxicam group. Based on these findings it is concluded that application of the tenoxicam after lumbar laminectomy did not effectively reduce arachnoiditis. Performing the most effective surgical technique without damage around tissue in a small surgical wound and having meticulous hemostasis in surgery seem to be the key for preventing arachnoiditis effectively.

[Neuroendoscope-assisted surgical treatment of spinal dural arteriovenous fistulas]

OBJECTIVE

To study the utility of neuroendoscope-assisted surgery in the treatment of spinal dural arteriovenous fistulas.

METHODS

From November 2008 to November 2010, 8 cases of spinal dural arteriovenous fistulas underwent neuroendoscope-assisted surgical treatment by a hemilaminectomy approach. Retrospective analyses were performed for their clinical manifestations, imaging findings, surgical approaches, postoperative recovery and follow-up profiles.

RESULTS

All were of single fistula. Under the assistance of neuroendoscope, the fistulas were found intra-operatively and the draining veins disconnected successfully. The results of post-operative angiography showed the disappearance of all draining veins. After a follow-up period of 3 - 35 months, 2 cases became asymptomatic, 5 cases improved obviously and 1 case had no change.

CONCLUSION

Neuroendoscope-assisted surgery is mini-invasive, safe and effective in the treatment of spinal dural arteriovenous fistulas.

Minimally invasive microsurgical treatment of cervical intraspinal extramedullary tumors

Removal of intraspinal tumors by the classic posterior midline approach with laminectomy may cause damage to and instability of cervical segments. We investigated whether the less invasive hemilaminectomy or hemi-semi-laminectomy can achieve satisfactory clinical outcomes in 39 patients with intraspinal extramedullary tumors of the cervical spine. Twenty-seven patients were treated with conventional microsurgery using a posterior midline approach; and were compared to 12 patients treated with hemilaminectomy or hemi-semi-laminectomy using a posterior midline approach. Patients were retrospectively reviewed and their preoperative and postoperative clinical status was measured using the Frankel Grade. The surgical time for the 27 patients who underwent a classical laminectomy was 3±0.39 hours and blood loss was 123±34 mL. Twenty-five patients had their tumors removed entirely, and two patients had partial removal. Twenty-six patients were followed-up for between 38 months and 7 years (mean=5 years), of whom 23 improved and three remained in a stable condition. One patient with a meningioma had a tumor recurrence 3 years post-operatively and underwent further surgery. The surgical time for the hemilaminectomy or hemi-semi-laminectomy group was 2.5±0.3 hours and blood loss was 88±18 mL. All patients were followed-up for between 26 and 42 months (mean=31 months) and 11 recovered to an improved grade while one remained in a stable condition. No patient had a tumor recurrence. The hemilaminectomy or hemi-semi-laminectomy approach achieved similar clinical outcomes to the conventional posterior midline laminectomy approach and was also associated with a shorter operative time, decreased intraoperative blood loss, greater preserved ligament and bone structure and a reduced deformity rate.

Posterior cervical decompressive laminectomy and lateral mass screw fixation

OBJECTIVE

To review the results and complications of cervical decompressive laminectomy and lateral mass screw fixation.

METHODS

This retrospective study was carried out between October 2006 and January 2010 at King Abdullah University Hospital, Irbid, Jordan. Over 40 months, 405 lateral mass screws were placed in 50 patients aged 22-65 years (17 females, and 33 males) for variable cervical pathologies including degenerative disease, trauma, and neoplasm. All cases were performed with a polyaxial screw/rod construct. Most patients had 14 mm length and 3.5 mm diameter screws placed. The screw location was evaluated by postoperative plain x-ray and CT. The facet joint, foraminal and foramen transversarium violation were also assessed.

RESULTS

All screws were placed using the Anderson or Sekhon methods. No patients experienced neural or vascular injury as a result of screw position. One patient needed screw repositioning. Three patients experienced superficial wound infection. Five patients experienced pain around the shoulder of C5 distribution that subsided over time. No patients had screw pullouts or symptomatic adjacent segment disease. Postoperative CT scanning showed no compromise of the foramen transversarium or neural foramen in the vast majority of the patients.

CONCLUSION

Lateral mass screw stabilization is a safe and effective surgical technique. This study exhibits the safety and effectiveness of lateral mass fixation for a variety of subaxial cervical spine disease.

[Prediction of spinal cord decompression after cervical laminoplasty: the SC-line]

OBJECTIVES

To report a new index (the SC-line) and a new classification for predicting of postoperative spinal cord decompression after cervical laminoplasty.

METHODS

From March 2008 to August 2009, MRI images of 25 patients treated with cervical laminoplasty were retrospectively studied. Using T2-weighted images of the cervical spine, point A was anterior point of the spinal cord at inferior endplate level of cranial compressed vertebra. Point B was anterior point of the spinal cord at superior endplate level of caudal compressed vertebra. The SC-line was defined as a line that connects A and B. Posterior surface of compressor at compression level did not exceed the line in Type I, connected the line in Type II, and exceeded it in Type III. Twenty-five patients who underwent cervical laminoplasty were classified into 3 groups according to the SC-line classification. The posterior shift of the spinal cord after the posterior decompression procedure was evaluated by using a modified gradation of degree of anterior spinal cord compression by MRI finding. The relationship between the degree of anterior spinal cord compression after surgery and the SC-line types were analyzed.

RESULTS

Preoperative cervical SC-line classification showed high correlations to the degree of spinal cord decompression. There were 3.82 ± 0.39 points in Type I before surgery, 3.90 ± 0.32 points in Type II, and 4.00 ± 0.00 points in Type III, respectively. After surgery, there were 1.15 ± 0.50 points in Type I, 2.70 ± 0.48 points in Type II, and 3.50 ± 0.55 points in Type III, respectively. Significant differences were found between each Type (F = 42.49, P < 0.01; Type I vs. Type II: P < 0.01; Type I vs. Type III: P < 0.01; Type II vs. Type III: P = 0.038).

CONCLUSION

SC-line can be used to predict the degree of postoperative spinal cord decompression following cervical laminoplasty.

[Combined anterior-posterior arthrodesis en patient with athetoid cerebral palsy who developed spondylotic cervical mielopathy. Case report and review of literature]

Spondylotic cervical mielopathy is a common complication in young patients with Cerebral Child Palsy with an important dystonic and athetoid component. Its surgical treatment is a challenge, due to elevate incidence of early faliure of the arthrodesis, both in anterior and posterior approaches. We report an historical review about the treatment of cervical mielopathy in this subgroup of patients and a clinical case in which we decided to realize decompression and arthtrodesis by a combined anterior and posterior approach, with lateral-mass screw placement, using botulinium toxin injections in the postoperative period, achieving a good clinical outcome.

Cauda equina syndrome and dural ectasia: rare manifestations in chronic ankylosing spondylitis

Cauda equina syndrome (CES) is a rare manifestation in patients with long-standing ankylosing spondylitis (AS). We report a 57-year-old male patient with a 30-year history of AS who developed CES in the past 4 years. The CT and MRI examinations showed unique appearances of dural ectasia, multiple dorsal dural diverticula, erosion of the vertebral posterior elements, tethering of the conus medullaris to the dorsal aspect of the spinal canal and adhesion of the nerve roots of the cauda equina to the wall of the dural sac. A large dural defect was found at surgery. De-adhesion of the tethered conus medullaris was performed but without significant clinical improvement. The possible aetiologies of CES and dural ectasia in patients with chronic AS are discussed and the literature is reviewed.

Bilateral open-door expansive laminoplasty using unilateral posterior midline approach with preservation of posterior supporting elements for management of cervical myelopathy and radiculomyelopathy--analysis of clinical and radiological outcome and surgical technique

BACKGROUND

The purpose of this study was to evaluate bilateral open-door cervical laminoplasty for management of cervical canal stenosis secondary to multisegmental cervical spondylosis and ossified posterior longitudinal ligament. The importance of unilateral posterior approach with preservation of posterior supporting element is emphasized.

METHODS

Thirty-four patients had expansive laminoplasty. Posterior tension band consisting of nuchal ligaments and supraspinous and interspinous ligaments was secured. Paraspinal deep extensor muscles attached to one side of spinous process were also preserved. Hydroxyapatite-collagen spacers were positioned between split laminae in midline and secured with Ethibond. All patients had features of myelopathy with weakness, hypertonia, clonus, and hyperreflexia in both upper and lower limbs. Bladder and bowel involvement was seen in 11.7% and sexual dysfunction in 5.8%. Preoperative dynamic study of cervical spine, MRI, and/or CT were done in all patients and compared with postoperative studies to see the efficacy of the surgical procedure.

RESULTS

Preoperative and postoperative neurosurgical cervical spine scale was used to compare results in relation to age, sex, duration of symptoms, neurosurgical cervical spine score, bladder, bowel, and sexual abnormalities. Elderly patients, lower neurosurgical score, signs and symptoms of more than 2 years, and bladder, bowel, and sexual dysfunction had poorer outcome. Complications were few. All patients had adequate diameter of spinal canal postoperatively. Cervical alignment and range of motion of segment subjected to laminoplasty were preserved satisfactorily in follow-up.

CONCLUSIONS

Bilateral open-door expansive laminoplasty using unilateral posterior midline approach provides preservation of posterior supporting tension band and excellent reconstruction of spinal canal. This technique also does not compromise contralateral paraspinal muscles attached to spinous process.

Latencies obtained of the somatosensory evoked potentials of the median and tibial nerve in rhesus monkey undergoing intrauterine laminectomy to simulate myelomeningocele

BACKGROUND

Somatosensory evoked potentials (SSEP) have been described as excellent indicators of the degree of medullar injury in degenerative and metabolic diseases of the central nervous system (CNS). The prevalence of neural tube defects (NTD) is 6 cases/10,000 live newborns worldwide. It is thought that genetic as well as environmental factors contribute to the etiology of NTD. The objective of this study was to analyze and compare the latencies obtained by means of SSEP in a clinically healthy monkey vs. rhesus monkeys with intrauterine surgery in order to simulate surgically the neural tube defect (myelomengocele) by performing an intrauterine laminectomy and in which later the defect was corrected.

METHODS

This study was performed using three non-human primates of the Macaca mulatta species. There were practice intrauterine surgeries in two monkeys to simulate the neurological defect produced by myelomeningocele, using the third monkey as control. For statistical methodology four monkeys were used. They were born by natural birth without any surgical manipulation. With the cesarean-obtained products, stimulation was performed of the tibial and median nerve.

RESULTS

We observed that the hind limbs were the most affected, in particular, the left afferent of the monkey. The spinal cord was exposed to amniotic fluid, and there were no significant differences in the forelimbs.

CONCLUSIONS

The use of SSEP provides valuable information regarding preservation of sensorial functions in a variety of experimental neurological abnormalities.

Cervical spine surgery: an historical perspective

BACKGROUND

Continued innovation in surgery requires a knowledge and understanding of historical advances with a recognition of successes and failures.

QUESTIONS/PURPOSES

To identify these successes and failures, we selectively reviewed historical literature on cervical spine surgery with respect to the development of (1) surgical approaches, (2) management of degenerative disc disease, and (3) methods to treat segmental instability.

METHODS

We performed a nonsystematic review using the keywords "cervical spine surgery" and "history" and "instrumentation" and "fusion" in combination with "anterior approach" and "posterior approach," with no limit regarding the year of publication. Used databases were PubMed and Google Scholar. In addition, the search was extended by screening the reference list of all articles.

RESULTS

Innovative surgical approaches allowed direct access to symptomatic areas of the cervical spine. Over the years, we observed a trend from posterior to anterior surgical techniques. Management of the degenerative spine has evolved from decompressive surgery alone to the direct removal of the cause of neural impingement. Internal fixation of actual or potential spinal instability and the associated instrumentation have continuously evolved to allow more reliable fusion. More recently, surgeons have developed the basis for nonfusion surgical techniques and implants.

CONCLUSIONS

The most important advances appear to be (1) recognition of the need to directly address the causes of symptoms, (2) proper decompression of neural structures, and (3) more reliable fusion of unstable symptomatic segments.

"No performance in surgery more interesting and satisfactory": Harvey Cushing and his experience with spinal cord tumors at the Johns Hopkins Hospital

Although Harvey Cushing was a neurosurgical pioneer, his work on the spine remains largely unknown. In fact, other than his own publications, Cushing's patients with pathological lesions of the spine who were treated while he was at the Johns Hopkins Hospital, including those with spinal cord tumors, have never been previously described. The authors report on 7 patients with spinal cord tumors that Cushing treated surgically between 1898 and 1911: 2 extradural, 3 intradural extramedullary, and 2 intramedullary tumors. The authors also describe 10 patients in whom Cushing performed an "exploratory laminectomy" expecting to find a tumor, but in whom no oncological pathological entity was found. Cushing's spine surgeries were limited by challenges in making the correct diagnosis, lack of surgical precedent, and difficulty in achieving adequate intraoperative hemostasis. Other than briefly mentioning 2 of the 4 adult patients in his landmark monograph on meningiomas, these cases-both those involving tumors and those in which he performed exploratory laminectomies--have never been published before. Moreover, these cases illustrate the evolution that Harvey Cushing underwent as a spine surgeon.

[The Biomechanics Influence of unilateral laminectomy and discectomy surgery on the adjacent different grades of Disc Degeneration]

OBJECTIVES

To study the stress distribution of the adjacent different grades of disc degeneration underwenting unilateral laminectomy and discectomy surgery using non-linear finite element analysis.

METHODS

Based on the lumbar CT scans, the finite element model (FEM) of lumbar spinal segment (L3-L5) was established. According to L3-L4 intervertebral disc degeneration, different grades of disc degeneration (healthy, mild, moderate and severe) models were established and unilateral laminectomy and discectomy surgery were also established. Physiological action such as flexion, extension, lateral bending and lateral rotation was simulated and the von Mises stress in the nucleus pulposus and annulus fibrosus matrix of L3-L4 disc was investigated.

RESULTS

After unilateral laminectomy and discectomy surgery, the extremum value of von Mises stress of nucleus pulposus and annulus fibrosus matrix was maximum during extension and minimus left bending in the healthy intervertebral disc. Compared with healthy disc, the increment of extremum value was found during left bending in the mildly degenerated disc. When the value decreased in the moderately degenerated disc, but still higher than that in the healthy disc. When the adjacent disc is severely degenerated, the extremum value of nucleus pulposus decreased, in addition to axial rotation, and even lower than that of healthy disc. The value of annulus matrix decreased and still higher than that of healthy disc, especially during left bending.

CONCLUSIONS

After unilateral laminectomy and discectomy surgery, avoiding lateral bending will reduce the abnormal stress in the degenerated disc and decreased the risk of accelerating disc degeneration.

A modified "far-lateral" approach for safe resection of retroodontoid dural cysts

Cystic mass lesions at the ventral craniocervical junction have been described only rarely in the past, however, they have received more attention with improved imaging modalities in recent years. These lesions have been approached by various operative procedures. A modified "far-lateral" approach combined with a C1 hemilaminectomy without fusion was used to safely remove the cyst and decompress the cervical medulla in a 72-year-old woman with cervicooccipital pain and paresthesia in both arms. Following surgery, complete resolution of symptoms was achieved, and no recurrence at 1 year follow-up was detected. A modified "far-lateral" approach offers several advantages when compared with other operation techniques.

The current state of minimally invasive spine surgery

Minimally invasive surgery for spinal disorders is predicated on the following basic principles: (1) avoid muscle crush injury by self-retaining retractors; (2) do not disrupt tendon attachment sites of key muscles, particularly the origin of the multifidus muscle at the spinous process; (3) use known anatomic neurovascular and muscle compartment planes; and (4) minimize collateral soft-tissue injury by limiting the width of the surgical corridor. The traditional midline posterior approach for lumbar decompression and fusion violates these key principles of minimally invasive surgery. The tendon origin of the multifidus muscle is detached, the surgical corridor is exceedingly wide, and significant muscle crush injury occurs with the use of powerful self-retaining retractors. The combination of these factors leads to well-described changes in muscle physiology and function. Minimally invasive posterior lumbar surgery is performed with table-mounted tubular retractors that focus the surgical dissection to a narrow corridor directly over the surgical target site. The path of the surgical corridor is chosen based on anatomic planes, specifically avoiding injury to the musculotendinous complex and the neurovascular bundle. With these relatively simple modifications in the minimally invasive surgical technique, significant improvements have been achieved in intraoperative blood loss, postoperative pain, and surgical morbidity. However, minimally invasive surgical techniques remains technically demanding, and a significant complication rate has been reported during a surgeon's initial learning curve for the procedures. Improvements in surgeon training along with long-term prospective studies will be needed for advancements in this area of spine surgery.

Hemilaminectomy for removal of extramedullary or extradural spinal cord tumors: medium to long-term clinical outcomes

PURPOSE

Laminectomy is generally the treatment of choice for removal of spinal tumors. However, it has been shown that laminectomy may cause instability due to damage of posterior elements of the spinal column, which may induce subsequent kyphosis in the future. Therefore, to reduce the risk of deformity and spinal instability after laminectomy, hemilaminectomy has been used. However, the medium to long-term effects of hemilaminectomy on spinal sagittal alignment is not well understood. The present study was performed to evaluate the clinical outcomes, including spinal sagittal alignment of patients, associated with spinal cord tumors treated by surgical excision using hemilaminectomy.

MATERIALS AND METHODS

Twenty hemilaminectomy operations at our institute for extramedullary or extradural spinal cord tumors in 19 patients were evaluated retrospectively with an average follow-up of 85 months (range, 40-131 months). Neurological condition was evaluated using the improvement ratio of the Japanese Orthopaedic Association Score (JOA score) for cervical, thoracic myelopathy, or back pain, and sagittal alignment by sagittal Cobb angle of the hemilaminectomied area.

RESULTS

The mean improvement ratio of neurological results was 56.7% in the cervical spine (p < 0.01, n = 10), 26.3% in the thoracic spine (not significant, n = 5), and 48.6% in the lumbar spine (NS, n = 5). The sagittal Cobb angle was 4.3 ± 18.0° in the preoperative period and 5.4 ± 17.6° at the latest follow-up, indicating no significant deterioration.

CONCLUSION

Hemilaminectomy is useful for extramedullary or extradural spinal cord tumors in providing fair neurological status and restoration of spinal sagittal alignment in medium to long-term follow-up.

Cervical laminoplasty construct stability: an experimental and finite element investigation

STUDY DESIGN

Experimental and finite element investigation of cervical laminoplasty.

OBJECTIVE

To determine the stability of the construct post cervical laminoplasty.

SUMMARY OF BACKGROUND DATA

Cervical laminoplasty is a widely used technique to widen the spinal canal dimensions without permanently removing the dorsal elements of the cervical spine. Although various laminoplasty procedures have been developed recently, the use of mini-plates to hold the lamina open and prevent restenosis of the spinal cord is a fairly new method and has not been thoroughly investigated.

METHODS

Biomechanical compression tests and finite element analyses were performed in this study. Sixteen cervical vertebrae (C3 - C6) were isolated from six cadaveric cervical spines (age at death 68 to 91 years; mean 85 years) and were used for compression tests. Out of the 16 vertebrae, four were without any surgical intervention and the remaining 12 were implanted with one of the two laminoplasty plates: open door (OD) graft. Each vertebra was randomly assigned to one of the three groups: OD plate (6), graft plate (6) or intact vertebrae (4). The intact and implanted vertebrae were potted and loaded to failure. Cross-head displacements and the corresponding reaction force throughout the test were recorded to determine the failure loads. A finite element model of the C5 cervical vertebra was created to accommodate the laminoplasty implants. Experimental loading and boundary conditions were simulated and the stress distribution in the lamina was predicted in response to the compressive loads.

RESULTS

A substantial increase in the sagittal canal diameter (27%-33%) and the spinal canal area (31.2%-47%) was observed at all levels. The strength of the implanted specimens was considerably decreased (by six to eight times) as compared to the intact specimens.

CONCLUSION

Experimentally obtained data can be combined with mathematical models, such as finite element models, to accurately predict the biomechanical behavior (stresses and strains) of implants and the posterior bone which may not be possible by the use of any other method.

[Minimally invasive cervical elastic laminoplasty - principles and surgical technique]

PURPOSE OF THE STUDY

To present a new technique of minimally invasive decompression of the cervical spinal canal using elastic and plastic deformation of the laminae.

MATERIAL AND METHODS

Short midline vertical incision provides an access to the superior aspect of the target spinous processes. Cranial edge of the lamina is located by a midline, muscle-sparing interspinous dissection. The spinous process is cut in mid-sagittal plane using a thin blade of an ultrasonic bone scalpel down to epidural space. The created sagittal cleavage of the spinous process is subjected to tension and elastic distraction by a custom-designed distractor (Aesculap, Germany). Gradual increase of the distraction force leads to a significant plastic deformation. This reduces the distraction force and allows for a wider exposure which, in turn, facilitates dural visualization, resection of the yellow ligament and undercutting of approximately a half of the adjacent intact laminae. After completion of decompression, the plastic arch expansion can be maintained either by interposed bone-graft or appropriately shaped cage secured by a circumferential suture to the spinous process. Soft tissue resection and permanent expansion of the laminae provide sufficient decompression of the cervical spinal cord. In multilevel stenosis, the desired laminae can be expanded using this technique. To achieve the same degree of canal expansion as that by a classic laminoplasty (C3-7), a skip technique can be utilized. This involves combining expansive laminoplasty of C4 and C6 with bilateral undercutting of C5 and partial undercutting of C3 and C7. This can be achieved through two short vertical incisions. Based on data and experience gained from testing on 11 cadavers, we applied this method in 7 patients requiring posterior cervical decompression.

RESULTS

The spinous process or laminae fractured during expansion in the initial 4 patients and the procedure required conversion to a minimally invasive laminectomy. Further modification of the distractor and spinous process splitting technique resulted in elimination of this complication in subsequent cases. In all remaining patients, sufficient canal expansion was achieved by soft tissue resection and distraction of laminae, typically reaching 5 - 8 mm. Minimally-invasive muscle-sparing midline approach provided very positive functional results in terms of postoperative pain and range of motion allowing for immediate mobilization without external bracing.

CONCLUSION

Minimally invasive, muscle sparing, expansive laminoplasty provides adequate spinal canal expansion. Use of this technique and its muscle-sparing nature potentially result in improvement of early functional outcomes when compared to standard laminoplasty techniques requiring lateral lamina-facet border exposure. However, the theoretical superiority of this technique will need to be clinically scrutinized in a well designed surgical outcome study.

[Open-door laminoplasty for the treatment of failed anterior cervical spine surgery]

OBJECTIVE

To evaluate the outcome of open-door laminoplasty for the treatment of failed anterior cervical spine surgery.

METHODS

From February 2003 to June 2009, 15 patients underwent open-door laminoplasty for the failed anterior cervical spine surgery. The causes of revision and the progression of disease were analyzed. Japanese Orthopedic Association (JOA) scores and Nurick grade were adopted to record the improvement of neurological status and walking ability.

RESULTS

Two patients were excluded for analysis because of lost follow-up and follow-up less than 12 months. The mean follow-up period after revision surgery for the other 13 patients was 26 months (ranged 13-52 months). The mean interval between the initial and revision surgery was 24 months (ranged 5 months to 6 years). The causes of revision were as following: degeneration of the adjacent segment in 2 cases, inadequate decompression in 5 cases, mis-diagnosis of ossification of posterior longitudinal ligament (OPLL) as myelopathy in 4 cases, and progression of OPLL in 2 cases. Posterior laminoplasty was recommended for each patient. After the operation, 13 patients improved neurologically with respect to JOA score, 12 patients improved their walking ability while 1 remained unchanged. The mean modified JOA scores improved from 10.5 to 13.8 (P<0.05), the average recovery rate was 53.0% after the revision operation. The mean overall Nurick grade was 3.1 preoperatively and 1.9 at the final follow-up (P<0.05), the mean improvement of the Nurick grade was 1.2. Complications included cerebrospinal fluid leakage in 1 case, new axial neck pain in 1 case, and transient C5 nerve root palsy in 1 case.

CONCLUSIONS

Open-door laminoplasty is a straightforward and effective treatment for failed anterior cervical spine surgery due to inadequate decompression, progressive OPLL or degeneration of the adjacent segment. The merit of the open-door laminoplasty for failed anterior spine fusion is able to avoid high risk from initial anterior cervical spine surgery.

Acute formation of lumbar discal cyst: what is the mechanism?

Lumbar discal cysts are extremely rare pathologies, with only few reports describing these lesions in the literature. Moreover, their definite pathogenesis is still unknown, with proposed theories based on radialogic and histologic findings. In this report, the authors present an acute formation of a discal cyst, which is reported for the first time. Also, we center our case on the discussion of the possible pathogenesis. Also, this is the first case of discal cyst reported in Turkey. A 67-year-old woman, whose complaints, and clinical and radiological findings demonstrated lumbar disc herniation with acute Modic 1 degererative changes of the adjacent end plates of L3-4 level. After medical and physical therapies, follow-up lumbar MRI has been taken to demonstrate a discal cyst formation on the adjacent intervertebral disc, showed cranially migrated cyst superior posterior on herniated disc, in 2 weeks period. The patient was treated by microsurgical resection of the cyst, and her complaints resolved completely.

Retrospective review of patient self-reported improvement and post-procedure findings for mild (minimally invasive lumbar decompression)

BACKGROUND

Lumbar spinal stenosis and neurogenic claudication functionally impact thousands of patients per year. Those who fail conservative therapies and are not surgical candidates due to co-morbid conditions have few interventional options available. The recently described mild® procedure (Minimally Invasive Lumbar Decompression) is a candidate to fill this void. While 2 studies have reported no major adverse events with this procedure, the typical post-procedure patient course has not been previously described.

OBJECTIVE

To examine the minor adverse events and periprocedural course associated with mild. Additionally, to evaluate the efficacy of the procedure with regard to pain relief and functional status.

DESIGN

Retrospective evaluation.

METHODS

Forty-two consecutive patients meeting magnetic resonance imaging (MRI) criteria for mild underwent the procedure performed by 2 interventional pain management physicians working at the same center. The pre and post procedure visual analog scale (VAS) as well as markers of global function were recorded. Major and minor adverse events were tracked and patient outcomes reported.

RESULTS

There were no major adverse events reported. Of the minor adverse events, soreness lasting 3.8 days was most frequently reported. No patients required overnight observation and only 5 required postoperative opioid analgesics. Patients self-reported improvement in function as assessed by ability to stand and ambulate for greater than 15 minutes, whereas prior to the procedure 98% reported significant limitations in these markers of global functioning. Visual analog pain scores were significantly decreased by 40% from baseline. Eighty-six percent of the patients reported that they would recommend the mild procedure to others.

CONCLUSION

The mild procedure appears to be a safe and likely effective option for treatment of neruogenic claudication in patients who have failed conservative therapy and have ligamentum flavum hypertrophy as the primary distinguishing component of the stenosis.

Axial pain after posterior cervical spine surgery: a systematic review

Posterior operative approach has been the standard treatment for cervical compressive myelopathy, and axial pain after laminoplasty or laminectomy as a postoperative complication is now gradually receiving more and more attention. The objective of this study was to provide a systematic review of the current understanding of axial pain after cervical laminoplasty and laminectomy, and summarize clinical features, influence factors and preventive measures of axial pain after posterior decompressive surgery based on a review of literature published in the English language. Axial pain distributes over nuchal, periscapular and shoulder regions. Posterior surgery is not the major cause of axial pain, but axial pain can be worsened by the procedure. There are many clinical factors that influence postoperative axial pain such as age, preoperative axial pain, different surgical technique and postoperative management, but most of them are still controversial. Several surgical modifications have been innovated to reduce axial pain. Less invasive surgery, reconstruction of the extensor musculature, avoiding detachment of the semispinalis cervicis muscle and early removal of external immobilization have proved to be effective. Axial pain is under the influence of multiple factors, so comprehensive methods are required to reduce and avoid the postoperative axial pain. Because of methodological shortcomings in publications included in this systematic review, different results from different studies may be produced due to differences in study design, evaluation criteria, sample size, and incidence or severity of axial pain. More high-quality studies are necessary for drawing more reliable and convincing conclusions.

Surgical treatment of a 180° thoracolumbar fixed kyphosis in a young achondroplastic patient: a one-stage "in situ" combined fusion and spinal cord translocation

An achondroplastic patient with a thoracolumbar kyphosis was first seen at the age of 16 at our institution. His only concern at that time was the aesthetic implication of his deformity. His physical examination was normal except for loss of the neurologic reflexes in the lower limbs. The radiographs showed a fixed 180° thoracolumbar kyphosis with correct frontal and sagittal balances. No spinal cord anomaly was found on MRI. Two years later, he developed a progressive neurogenic claudication of the lower limbs. He was still neurologically intact at rest. The MRI showed an abnormal central spinal cord signal in front of the apex of the kyphosis associated with the narrow congenital spinal canal. In regards to this progressive neurological worsening, a surgical treatment was decided. We decided to perform a front and back arthrodesis combined with a spinal cord decompression without reduction of the deformity. A five-level hemilaminotomy was performed with a posterior approach at the kyphosis deformity. The spinal cord was individualised onto 10 cm and the left nerve roots were isolated. A decancellation osteotomy of the three apex vertebrae and a disc excision were performed. The posterior aspect of the vertebral body was then translated forward 2 cm and in association with the spinal cord. Two nerve roots were severed laterally to approach the anterior part of the kyphosis and a peroneal strut graft was inlayed anterolaterally. A complementary anterior and a right posterolateral fusion was made with cancellous bone. The patient was immobilised in a cast for 3 months relayed by a thoracolumbosacral orthosis for 6 months. At 3 years follow-up, the neurogenic claudication had disappeared. No worsening of the kyphosis was observed. His only complaint is violent electric shock in the lower limbs with any external sudden pressure on the spinal cord in the area uncovered by bone.