bluuebunny/crossref_metadata_2025 huggingface dataset:
Vertebroplasty in focal Paget disease of the spine
Authors: Kremer M. Adam , Fruin Al , Larson Theodore C. , Roll John , Weil Robert J.
Published: May 2009

✓ Paget disease is an idiopathic metabolic disease of bone that may involve the axial and appendicular skeleton. In up to one third of patients there may be pagetoid involvement of the spine, which can cause back pain and vertebral collapse, with instability or myeloradiculopathy. Although medical therapy is the mainstay of treatment, decompressive surgery or stabilization may be required. The authors report on a case of localized Paget disease of the spine treated successfully by performing percutaneous vertebroplasty. They propose this procedure as a useful intervention that can be undertaken safely in patients with spinal Paget disease, in whom acquisition of a transpedicular biopsy sample is required as part of diagnosis.
Paramedian transmuscular access to C-3 dumbbell-type neurofibroma without paravertebral muscle dissection from the spinous process or facetectomy
Authors: Nakano Shinichi , Yoneyama Takumi , Sugimoto Tetsuaki , Wakisaka Shinichiro
Published: May 2009

✓ SThe authors devised a paramedian transmuscular approach to the C2–3 facet joint that enabled total removal of C-3 dumbbell-type neurofibroma; dissection of the paravertebral muscles from the spinous process was not required and the facet joint was preserved. Only splitting or retraction of the paravertebral muscles was necessary. The anatomical features and procedures involved in muscle splitting are described.
One-stage three-dimensional correction and fusion: a multilevel posterior lumbar interbody fusion procedure for degenerative lumbar kyphoscoliosis
Authors: Hasegawa Kazuhiro , Homma Takao
Published: May 2009

✓ Surgery for degenerative lumbar kyphoscoliosis (DLKS) is very challenging because the curve has become rigid due to circumferential osteoarthritic changes. Therefore, a standard procedure involving correction and fusion after decompression of the nerves has not yet been established. The authors have been searching for an effective procedure that provides adequate decompression and three-dimensional (3D) correction for symptomatic DLKS. In this report they describe a new 3D correction and fusion technique involving multilevel posterior lumbar interbody fusion. They analyze the results obtained in the first 23 cases and discuss the advantages and disadvantages of the procedure. The correction effect was excellent, and compared with other instrumentation-assisted procedures, this surgery is not remarkably invasive. Although the procedure is limited in achieving normal sagittal alignment and the acceleration rate of adjacent-disc degeneration remains relatively high, it is an option for the rigid deformity characterized by DLKS.
Pedicle screw fixation for isthmic spondylolisthesis: does posterior lumbar interbody fusion improve outcome over posterolateral fusion?
Authors: La Rosa Giovanni , Conti Alfredo , Cacciola Fabio , Cardali Salvatore , La Torre Domenico , Gambadauro Nicola Maria , Tomasello Francesco
Published: May 2009

Object. Posterolateral fusion involving instrumentation-assisted segmental fixation represents a valid procedure in the treatment of lumbar instability. In cases of anterior column failure, such as in isthmic spondylolisthesis, supplemental posterior lumbar interbody fusion (PLIF) may improve the fusion rate and endurance of the construct. Posterior lumbar interbody fusion is, however, a more demanding procedure and increases costs and risks of the intervention. The advantages of this technique must, therefore, be weighed against those of a simple posterior lumbar fusion.

Methods. Thirty-five consecutive patients underwent pedicle screw fixation for isthmic spondylolisthesis. In 18 patients posterior lumbar fusion was performed, and in 17 patients PLIF was added. Clinical, economic, functional, and radiographic data were assessed to determine differences in clinical and functional results and biomechanical properties.

At 2-year follow-up examination, the correction of subluxation, disc height, and foraminal area were maintained in the group in which a PLIF procedure was performed, but not in the posterolateral fusion—only group (p < 0.05). Nevertheless, no statistical intergroup differences were demonstrated in terms of neurological improvement (p = 1), economic (p = 0.43), or functional (p = 0.95) outcome, nor in terms of fusion rate (p = 0.49).

Conclusions. The authors' findings support the view that an interbody fusion confers superior mechanical strength to the spinal construct; when posterolateral fusion is the sole intervention, progressive loss of the extreme correction can be expected. Such mechanical insufficiency, however, did not influence clinical outcome.
Factors affecting reduction in low-grade lumbosacral spondylolisthesis
Authors: Naderi Sait , Manisali Metin , Acar Feridun , Özaksoy Dinç , Mertol Tansu , Arda M. Nuri
Published: May 2009

Object. Lumbosacral spondylolisthesis (LSS) is a common disorder that often requires a stabilization and fusion procedure. The aim of this study was to determine the early neuroimaging-detected results of instrumentation-assisted (in situ) fusion with no attempt at surgical reduction of the deformity in patients with low-grade LSS. The neuroimaging results were evaluated to determine the extent of reduction and its correlation with different parameters.

Methods. Thirty patients with low-grade LSS underwent short-segment transpedicular screw fixation; surgical reduction was not attempted. All patients underwent plain anteroposterior and lateral lumbar radiography, flexion—extension lateral lumbar radiography, and computerized tomography and magnetic resonance imaging of the lumbar spine before and after surgery. Postoperative measurements were determined on the late (9 to 12—month) postoperative radiographs. The findings were recorded and grouped. Correlation analysis was performed among the radiological findings, body mass index, age, and sex. Paired-sample t-tests were performed for each paired group to determine statistically significant differences.

There was no significant difference in extent of deformity reduction in patients with different lordotic angles, sagittal-plane rotation angles, and intervertebral disc heights. The extent of reduction was statistically significant at the L4–5 level (p < 0.05), in patients younger than 50 years of age (p < 0.05), and in those in whom the facet joint angle was increased (p < 0.05).

Conclusions. The authors found that in cases of low-grade LSS, short-segment posterior stabilization (in situ fusion and fixation) does not require surgical reduction and in fact is associated with a measurable reduction when used as the sole treatment.
Thoracic myelopathy caused by ossification of the ligamentum flavum: a report of 18 cases
Authors: Hamouda Karim Ben , Jemel Hafedh , Haouet Slim , Khaldi Moncef
Published: May 2009

Object. Thoracic myelopathy caused by ossification of the ligamentum flavum (OLF) is a rare entity, most evident in Japan. The authors studied the clinical manifestations, radiological aspects, surgical treatment, and pathogenesis of this disease.

Methods. Eighteen patients with OLF-induced thoracic myelopathy underwent laminectomy. The severity of myelopathy varied. Complete paraplegia was seen in three cases. Compression of the upper and middle third of the thoracic spine was evident in six cases and of the lower third in 12 cases. Multilevel OLF was demonstrated in 13 cases. In most cases, the ossified ligamentum flavum appears as a V-shaped lesion on computerized tomography and magnetic resonance images. In all patients the diameter of the posterior spinal canal, already narrowed, was further exacerbated by the OLF.

Laminectomy was limited to the levels of compression, and the ligamentum flavum was resected in all cases. The symptoms and signs improved in 13 cases and stabilized in four cases. In one case symptoms recurred as a result of ossified lesions forming at other sites. Histological examination showed that the mode of development of the ossified ligaments was endochondral ossification.

Conclusions. Reports of OLF-induced myelopathy are rare and mainly described in Japan. The incidence also seems high in North Africa. An early laminectomy limited to the level of compression is recommended. Ossified ligamentum flavum is different from the calcification of the ligamentum flavum, which is due to crystal deposits.
Prevention of postoperative posterior tethering of spinal cord after resection of ependymoma
Authors: Goto Takeo , Ohata Kenji , Takami Toshihiro , Nishikawa Misao , Nishio Akimasa , Morino Michiharu , Tsuyuguchi Naohiro , Hara Mitsuhiro
Published: May 2009

Object. The authors evaluated an alternative method to avoid postoperative posterior tethering of the spinal cord following resection of spinal ependymomas.

Methods. Twenty-five patients with spinal ependymoma underwent surgery between 1978 and 2002. There were 16 male and nine female patients whose ages at the time of surgery ranged from 14 to 64 years (mean 41.8 years). The follow-up period ranged from 6 to 279 months (mean 112.4 months). In the initial 17 patients (Group A), the procedure to prevent arachnoidal adhesion consisted of the layer-to-layer closure of three meninges and laminoplasty. In the subsequently treated eight patients (Group B), the authors performed an alternative technique that included pial suturing, dural closure with Gore-Tex membrane—assisted patch grafting, and expansive laminoplasty. In Group A, postoperative adhesion was radiologically detected in eight cases (47%), and delayed neurological deterioration secondary to posterior tethering of the cord was found in five cases. In Group B, there was no evidence of adhesive posterior tethering or delayed neurological deterioration. A significant intergroup statistical difference was demonstrated for radiologically documented posterior tethering (p < 0.05, Fisher exact test). Moreover, patients with radiologically demonstrated posterior tethering suffered a significant delayed neurological functional deterioration (p < 0.01, Fisher exact test).

Conclusions. This new technique for closure of the surgical wound is effective in preventing of postoperative posterior spinal cord tethering after excision of spinal ependymoma.
In vitro biomechanical effects of reconstruction on adjacent motion segment: comparison of aligned/kyphotic posterolateral fusion with aligned posterior lumbar interbody fusion/posterolateral fusion
Authors: Sudo Hideki , Oda Itaru , Abumi Kuniyoshi , Ito Manabu , Kotani Yoshihisa , Hojo Yoshihiro , Minami Akio
Published: May 2009

Object. Posterior lumbar interbody fusion (PLIF) was developed to overcome the limitations of posterolateral fusion in correcting spinal deformity and maintaining lumbar lordosis. In this study the authors compare the biomechanical effects of three different posterior reconstructions on the adjacent motion segment.

Methods. Ten calf spinal (L2—S1) specimens underwent nondestructive flexion—extension testing (± 6 Nm). The specimens were destabilized at the L5—S1 levels after intact testing. This was followed by pedicle screw fixation with and without interbody cages as follows: 1) with straight rods (“aligned” posterolateral fusion); 2) with kyphotically prebent rods (“kyphotic” posterolateral fusion); and 3) with interbody cages combined with straight rods (“aligned” PLIF/posterolateral fusion). The range of motion (ROM) of the operative segments, the intradiscal pressure (IDP), and longitudinal lamina strain in the superior adjacent segment (L4–5) were analyzed.

The ROM associated with aligned PLIF/posterolateral fusion-treated specimens was significantly less than both the aligned and kyphotic posterolateral fusion-treated procedures in both flexion and extension loading (p < 0.05). The aligned PLIF/posterolateral fusion was associated with greater IDP and the lamina strain compared with the aligned and kyphotic posterolateral fusion groups in flexion loading. Under extension loading, greater IDP and lamina strain were present in the kyphotic posterolateral fusion group than in the aligned posterolateral fusion group. The highest IDP and lamina strain were shown in the aligned PLIF/posterolateral fusion group.

Conclusions. Compared with kyphotic posterolateral fusion, PLIF may lead to even higher load at the superior adjacent level because of the increased stiffness of the fixed segments even if local kyphosis is corrected by PLIF.
Spontaneous regression of symptomatic lumbar synovial cysts
Authors: Houten John K. , Sanderson Scott P. , Cooper Paul R.
Published: May 2009

✓ Synovial cysts emanating from the lumbar facet joints may compromise the spinal canal and produce symptoms of radiculopathy or stenosis. Good results have been reported after excision of the symptomatic lesions. There are limited data, however, on the natural history involving nonoperative management and little information to suggest that these lesions ever regress spontaneously. The authors report on three patients in whom symptomatic lumbar synovial cysts spontaneously resolved and review the relevant literature.
One-level one-sided lumbar disc surgery with and without microscopic assistance: 1-year outcome in 114 consecutive patients
Authors: Türeyen Kudret
Published: May 2009

Object. The aim of this study was to compare the outcomes following macrodiscectomy and microsurgery for one-level one-sided lumbar disc excision.

Methods. The authors prospectively studied 114 consecutive patients who underwent microdiscectomy (Group A, 63 patients [36 men, 27 women]) and macrodiscectomy (Group B, 51 patients [29 men, 22 women]) for one-level unilateral first-time lumbar disc herniation. Microdiscectomy was considered to involve a small incision with removal or opening of the ligamentum flavum, no or minimal bone excision, and use of the operating microscope to remove the disc material. Laminectomy combined with macrodiscectomy was defined as any operation requiring a large opening in or complete removal of the unilateral lamina. Diagnosis was confirmed by magnetic resonance imaging. A 1-year follow-up investigation was also conducted. Relief of radicular pain, improvement in muscle power, and changes in sensory and/or reflex abnormality were documented. Assessment of outcome was performed using the modified Stauffer—Coventry criteria.

Good or excellent results were demonstrated in 90% of Group A and 89% of Group B patients (p > 0.05). One patient in each group underwent reoperation. There was infection over the fascia in two Group A patients. Mean operative time (± standard deviation) was 54 ± 5.65 minutes in Group A and 25 ± 7.07 minutes in Group B (p < 0.01). Median length of the incision was 4 and 6 cm in Group A and Group B, respectively (p < 0.05). The length of postoperative inpatient stay was 1 day in both groups (p > 0.05). Patients in the microsurgery-treated group returned to work in less time: 85% of Group A and 58% of Group B patients returned to their work within 4 weeks (p < 0.001). Some patients in each group (15% in Group A and 45% in Group B) needed narcotic analgesic medication at least twice between the 1st month and 1st year after the surgery (p < 0.001).

Conclusions. Microdiscectomy allows the surgeon good visualization and is less traumatic to the involved tissues. Interestingly, the results of this study indicated that microsurgery does not reduce hospitalization time, nor does it improve the overall surgery-related outcome. The main differences between the two procedures were length of the incision and operative time. The author found that lumbar microdiscectomy allows patients earlier return to work and/or normal life with less reliance on postoperative narcotic analgesic agents.
Clinical and radiological evaluation of the Codman semiconstrained load-sharing anterior cervical plate: prospective multicenter trial and independent blinded evaluation of outcome
Authors: Casha Steven , Fehlings Michael G.
Published: May 2009

Object. Semiconstrained load-sharing implants for spinal fixation accommodate change in the screw—plate interface as bone grafts shrink. The authors evaluated the clinical and radiological outcome in patients after placement of the Codman anterior cervical plate (ACP) system, which allows change in the screw—plate angle.

Methods. The authors undertook a 10-center prospective study with independent blinded evaluation. All patients underwent cervical fusion and placement of ACPs. Clinical and radiological evaluations were performed at 1, 3, 6, 12, and 24 months. Radiographs were examined for screw angles, construct height, fusion, and screw fracture or displacement.

One hundred ninety-five patients were enrolled. The mean follow-up period was 17 months. At 24 months neurological improvement was demonstrated in 68.7% and pain improvement in 76.6% of the patients. Fusion was successful in 93.8%. Varying degrees (most minor) of hardware-related failure occurred in 10.4% of cases; however, reoperation was required in only four (2.1%). A significant change in screw angles occurred over time (mean 6.4° in caudal screw angle [p < 0.001] and 2.4° in the rostral screw angle [p = 0.003]). These changes plateaued by 6 months. A change in construct height (mean 3.48 mm) occurred by 6 months (p < 0.05).

Conclusions. Based on an independent blinded evaluation, the Codman ACP provides effective fixation with load sharing and is effective in achieving fusion with a 94% success rate. Direct comparison with rigidly locked devices is required to establish definitively the optimal method for anterior cervical fixation.
Low-dose radiotherapy for the inhibition of peridural fibrosis after reexploratory nerve root decompression for postlaminectomy syndrome
Authors: Gerszten Peter C. , Moossy John J. , Flickinger John C. , Welch William C.
Published: May 2009

Object. The authors of clinical studies have demonstrated a significant association between the presence of extensive post—lumbar discectomy peridural scar formation and the recurrence of low-back and radicular pain. Low-dose perioperative radiotherapy has been demonstrated to inhibit peridural fibrosis after laminectomy in animal models. The present study was designed to evaluate the clinical efficacy of preoperative irradiation in patients with failed—back surgery syndrome due to peridural fibrosis who underwent reexploration and nerve root decompression.

Methods. Ten patients with symptomatic post—discectomy peridural fibrosis were randomized. Half of the patients underwent 700-cGy external-beam irradiation to the operative site 24 hours prior to reexploration and decompressive treatment of their symptomatic nerve root(s) (treatment group) and the other half underwent reexploration and decompressive treatment without preoperative irradiation (control group). All patients underwent simulated irradiation so neither patient nor surgeon was aware of the patient's group. In all patients the antiadhesion product ADCON-L was placed over the affected nerve root at the time of surgery. Clinical outcome was assessed using the American Association of Neurological Surgeons/Congress of Neurological Surgeons Joint Section Lumbar Disc Herniation Study Questionnaire at baseline, 6 weeks, 3 months, and 1 year follow up.

Five men and five women (mean age 42 years) underwent randomization and surgery. Three patients underwent reexploration at L4–5, four at L5—S1, and three at both levels. No complication was associated with irradiation, and no new neurological deficits occurred. At 1-year follow-up examination, three irradiation-treated patients were pain free and two experienced improvement. In the control group, three patients experienced improved pain relief and two were unchanged. There was a trend toward better outcome at 1 year in the radiotherapy-treated group (p = 0.056).

Conclusions. Preoperative low-dose external-beam irradiation improved clinical outcomes after reexploration and decompression of nerve roots affected by postlaminectomy peridural fibrosis causing radicular pain. The addition of preoperative irradiation may improve outcome in patients who undergo reoperation for recurrent radicular pain associated with a significant amount of peridural fibrosis, particularly now that no antiadhesion product is available for clinical use.
Mechanism of the spinal cord injury and the cervical spondylotic myelopathy: new approach based on the mechanical features of the spinal cord white and gray matter
Authors: Ichihara Kazuhiko , Taguchi Toshihiko , Sakuramoto Itsuo , Kawano Shunichi , Kawai Shinya
Published: May 2009

Object. The authors have previously investigated the mechanical properties of the white and gray matter in the bovine cervical spinal cord, demonstrating that the gray matter is more rigid, although more fragile, than the white matter. In the present study they conducted additional tensile tests on the bovine cervical spinal cord by changing strain levels and strain rates applied to the white and gray matter.

Methods. Based on their testing, the authors found the following: 1) Stress within the spinal cord relaxes over time. 2) Intracord stress is related to the strain rates or levels. The finite element method was used to compute the stress distribution within the spinal cord under three compressive loading conditions. Results from the computations showed a different stress distribution in the white and gray matter, where the distribution of stress varied with strain rate, compression volume, and the position of compression.

Conclusions. These differences in mechanical properties between the white and gray matter constitute different mechanisms contributing to the development of tissue damage and clinical symptoms.
Changes in nerve root motion and intraradicular blood flow during intraoperative femoral nerve stretch test
Authors: Kobayashi Shigeru , Suzuki Yoshihiko , Asai Takahiro , Yoshizawa Hidezo
Published: May 2009

Object. It is not known whether changes in intraradicular blood flow (IRBF) occur during the femoral nerve stretch test (FNST) in patients with lumbar disc herniation. An FNST was conducted in patients with lumbar disc herniation to observe the changes in IRBF, and results were then compared with clinical features.

Methods. The study was composed of four patients with L3–4 disc herniation who underwent microdiscectomy. Patients were placed prone immediately before surgery, so that their knee flexed on the operating table with the hip joint kept in hyperextension, and the FNST was performed to confirm at which region pain developed in the anterolateral thigh. During the operation, the hernia-affected nerve roots were visualized under a microscope. The needle sensor of a laser Doppler flowmeter was then inserted into each nerve root immediately above the hernia, and the change in IRBF was measured during the intraoperative FNST. After removal of the herniated disc, a similar procedure was repeated and IRBF was measured again.

The intraoperative FNST showed that the hernia compressed the nerve roots and there was marked disturbance of gliding, which was reduced to only a few millimeters. During the test, IRBF decreased by 92.8 to 100% (mean 96.9 ± 3.7% [± standard error of the mean]) relative to the blood flow before the test. This study demonstrated that the blood flow in the nerve root is reduced when the nerve root is compressed in vivo.

Conclusions. The intraoperative FNST showed that the hernia compressd the nerve roots and there was marked disturbance of gliding, which was reduced to only a few millimeters. During the test, IRBF decreased by 92.8 to 100% (96.9 ± 3.7% [mean ± standard error of the mean]).
Upper thoracic spinal cord herniation after traumatic nerve root avulsion
Authors: Dasilva Victor R. , Al-Gahtany Mubarak , Midha Rajiv , Sarma Dipanka , Cooper Perry
Published: May 2009

✓ Transdural herniation of the spinal cord, a rare but well-documented entity, has been reported sporadically for more than 25 years as a possible cause for various neurological signs and symptoms ranging from isolated sensory or motor findings to myelopathy and Brown—Séquard syndrome. The authors report, to the best of their knowledge, the first case of upper thoracic spinal cord herniation occurring after traumatic nerve root avulsion.
Fracture of S1–S2 after L4—S1 decompression and fusion
Authors: Bose Bikash
Published: May 2009

✓ The author describes a woman in whom an S1–2 fracture developed after L4—S1 decompression and fusion. Osteoporosis was not present, but the lesion failed to respond to conservative therapy, necessitating surgical extension of the spinal fusion. Although biomechanical complications of lumbosacral fusion are uncommon, pseudarthrosis, degenerative spondylolisthesis, and stress fractures have been reported. To date, only four cases of sacral stress fracture appear in the literature, all involving female patients and reportedly associated with osteoporosis. Unlike the present case, the fracture resolved satisfactorily in all cases with conservative treatment.
Three-dimensional fluoroscopy-guided percutaneous thoracolumbar pedicle screw placement
Authors: Holly Langston T. , Foley Kevin T.
Published: May 2009

✓ The authors sought to evaluate the feasibility and accuracy of three-dimensional (3D) fluoroscopic guidance for percutaneous placement of thoracic and lumbar pedicle screws in three cadaveric specimens.

After attaching a percutaneous dynamic reference array to the surgical anatomy, an isocentric C-arm fluoroscope was used to obtain images of the region of interest. Light-emitting diodes attached to the C-arm unit were tracked using an electrooptical camera. The image data set was transferred to the image-guided workstation, which performed an automated registration. Using the workstation display, pedicle screw trajectories were planned. An image-guided drill guide was passed through a stab incision, and this was followed by sequential image-guided pedicle drilling, tapping, and screw placement. Pedicle screws of various diameters (range 4–6.5 mm) were placed in all pedicles greater than 4 mm in diameter. Postoperatively, thin-cut computerized tomography scans were obtained to determine the accuracy of screw placement.

Eighty-nine (94.7%) of 94 percutaneous screws were placed completely within the cortical pedicle margins, including all 30 lumbar screws (100%) and 59 (92%) of 64 thoracic screws. The mean diameter of all thoracic pedicles was 6 mm (range 2.9–11 mm); the mean diameter of the five pedicles in which wall violations occurred was 4.6 mm (range 4.1–6.3 mm). Two of the violations were less than 2 mm beyond the cortex; the others were between 2 and 3 mm.

Coupled with an image guidance system, 3D fluoroscopy allows highly accurate spinal navigation. Results of this study suggest that this technology will facilitate the application of minimally invasive techniques to the field of spine surgery.
Lumbar interbody fusion: state-of-the-art technical advances
Authors: Mummaneni Praveen V. , Haid Regis W. , Rodts Gerald E.
Published: May 2009

✓ During the past few decades, three techniques have been used to achieve circumferential lumbar interbody fusion (LIF). They include posterior LIF, anterior LIF with supplemental posterior fixation, and transforaminal LIF. In this article, the authors describe the indications and contraindications for the use of interbody fusion. The advantages and disadvantages of each will be discussed in detail. Additionally, strategies for minimally invasive access and options for interbody spacer materials will be discussed.
Cervical magnetic resonance imaging abnormalities not predictive of cervical spine instability in traumatically injured patients
Authors: Horn Eric M. , Lekovic Gregory P. , Feiz-Erfan Iman , Sonntag Volker K. H. , Theodore Nicholas
Published: May 2009

Object.Identifying instability of the cervical spine can be difficult in traumatically injured patients. The goal of this study was to determine whether cervical abnormalities demonstrated on magnetic resonance (MR) imaging are predictive of spinal instability.

Methods.Data in all patients admitted through the Level I trauma service at the authors' institution who had undergone cervical MR imaging were retrospectively reviewed. The reasons for MR imaging screening were neurological deficit, fracture, neck pain, and indeterminate clinical examination (for example, coma). Abnormal soft-tissue (prevertebral or paraspinal) findings on MR imaging were correlated with those revealed on computerized tomography (CT) scanning and plain and dynamic radiography to determine the presence/absence of cervical instability.

Of 6328 patients admitted through the trauma service, 314 underwent MR imaging of the cervical spine. Of 166 patients in whom CT scanning or radiography demonstrated normal findings, 70 had undergone MR imaging that revealed abnormal findings. Of these 70 patients, 23 underwent dynamic imaging, the findings of which were normal. In each case of cervical instability (65 patients) CT, radiographic, and MR imaging studies demonstrated abnormalities. Furthermore, there were 143 patients with abnormal CT or radiographic study findings, in 13 of whom MR imaging revealed normal findings. Six of the latter underwent dynamic testing, which demonstrated normal results.

Conclusions.Magnetic resonance imaging is sensitive to soft-tissue injuries of the cervical spine. When CT scanning and radiography detect no fractures or signs of instability, MR imaging does not help in determining cervical stability and may lead to unnecessary testing when not otherwise indicated.
Synovial cysts of the thoracic spine
Authors: Cohen-Gadol Aaron A. , White J. Bradley , Lynch James J. , Miller Gary M. , Krauss William E.
Published: May 2009

Object.Thoracic synovial cysts (TSCs) are rare and are usually the subject of case reports. The authors studied the clinical manifestations, radiological aspects, and surgical treatment in a series of patients at their institution who harbored TSCs. They also review the literature to discuss the potential factors involved in the pathogenesis of this lesion.

Methods.A database search of 16,000 patients who underwent decompressive spine surgery at the Mayo Clinic (Rochester, MN) between 1976 and 2003 disclosed nine patients (0.06%) in whom a diagnosis of TSC had been made. All patients were men. The mean age at presentation was 73 ± 5 years and mean duration of symptoms was 5 ± 3 months. The mean duration of follow up was 4 ± 3 years.

The patients had no history of trauma or spine surgery. All patients had spastic paraparesis; two had urinary difficulties. Detailed neurological examination revealed myelopathy and radiculopathy with a sensory level of T10—L4. Magnetic resonance imaging revealed bilateral cysts in four patients and unilateral lesions in five. Three of the cysts were at the T-10 interspace, seven at the T-11 interspace, and three at the T-12 interspace. Seven cysts were on the right and six were on the left. Computerized tomography myelography performed in five patients revealed a gas bubble in the TSC in two patients. All patients underwent laminectomy/partial facetectomy, excision of the cyst, and decompression of the thecal sac and nerve root without any complications. None of these patients underwent a fusion. Eight patients (89%) experienced moderate to excellent relief of their preoperative signs and symptoms and one patient (11%) remained stable. There was no evidence of cyst recurrence at the site of surgery or other spinal segments at follow-up examination in any patient.

Conclusions.When compared with their lumbar and cervical spine counterparts, TSCs are exceedingly rare. Their rarity may be explained by the decreased mobility of the thoracic spinal segments. The origin of TSCs is more likely degenerative rather than traumatic. Based on their experience and the follow-up duration, surgery provided durable relief from symptoms.
Surgical treatment of lumbosacral plexus injuries
Authors: Lang Eva Maria , Borges Jörg , Carlstedt Thomas
Published: May 2009

Object. The purpose of this study was to analyze therapeutic possibilities and clinical outcomes in patients with lumbosacral plexus injuries to develop surgical concepts of treatment.

Methods. In a retrospective investigation 10 patients with injuries to the lumbosacral plexus were evaluated after surgery. The patients were assessed clinically, electrophysiologically, and based on the results of magnetic resonance imaging and computerized tomography myelography. In most patients a traction injury had occurred due to severe trauma that also caused pelvic fractures. In most cases the roots of the cauda equina of the lumbosacral plexus had ruptured. In cases of spinal root ruptures repair with nerve grafts were performed. In cases in which proximal stumps of the plexus could not be retrieved palliative nerve transfers by using lower intercostals nerves or fascicles from the femoral nerve were performed.

Conclusions. Lesions of the proximal spinal nerves and cauda equina occur in the most serious lumbosacral plexus injuries. Patients with such injuries subjected to reconstruction of spinal nerves, repair of ventral roots in the cauda equina, and nerve transfers recovered basic lower-extremity functions such as unsupported standing and walking.
Suspended laminoplasty for wide posterior cervical decompression and intradural access: results, advantages, and complications
Authors: Casha Steven , Engelbrecht H. Andries , DuPlessis Stephan J. , Hurlbert R. John
Published: May 2009

Object.Cervical laminoplasty is a recognized technique commonly used for multilevel posterior cervical decompression, and it is favored over laminectomy for maintaining spinal stability. Traditional hinge techniques, however, limit lateral exposure on one side and can limit dural exposure. The authors present their experience with a modified laminoplasty technique incorporating complete laminectomy and placement of titanium miniplate instrumentation. This method allows wide bilateral posterior decompression and unobscured dural access.

Methods.Twenty-eight patients (mean age 57 years) underwent cervical laminoplasty during a 4-year period. Twenty-seven patients presented with progressive cervical myelopathy. Seventeen patients (61%) had degenerative spondylotic stenosis; nine (32%) underwent resection of an intradural neoplasm. A mean of 3.5 levels were exposed and reconstructed. The follow-up period ranged from 4 months to 4 years (mean 15 months). The mean angular extension—flexion displacement measured between C-1 and C-7 was unchanged postoperatively, with preserved mobility across laminoplasty-treated segments in all patients. The anteroposterior diameter of the spinal canal increased 3.6 mm (27.2%) postoperatively (p = 0.004). In one patient an asymptomatic postoperative kyphosis developed. There were five cases of postoperative infection. One superficial infection resolved after intravenous antibiotic therapy alone, and four deep infections required surgical reexploration.

Conclusions.The advantages of this technique over other laminoplasty methods include wide lateral spinal canal and intradural access, as well as preserved motion with partial restoration of the posterior tension band.
A biomechanical comparison of supplementary posterior translaminar facet and transfacetopedicular screw fixation after anterior lumbar interbody fusion
Authors: Kim Sung-Min , Lim T. Jesse , Paterno Josemaria , Kim Daniel H.
Published: May 2009

Object. Facet screw fixation is the lowest profile lumbar stabilization method. In this study the immediate biomechanical stability provided by the two different types of fixation are compared: translaminar facet screw (TLFS) and transfacetopedicular screw (TFPS) placement after anterior lumbar interbody fusion (ALIF) using a femoral ring allograft. Both facet screw fixation types were also compared with the gold standard, transpedicular screw and rod (TSR) fixation.

Methods. Twenty-four human lumbosacral spines were tested in the following sequence: intact state, after discectomy, after ALIF, and after TLFS, TFPS, or TSR fixation. Intervertebral motions were measured by a video-based motion capture system. The range of motion (ROM) and neutral zone (NZ) were compared for each loading to a maximum of 7.5 Nm.

The ROMs for stand-alone ALIFs were less than but similar to those of the intact spine, but NZs were slightly increased in all modes. The ROMs for both TLFS and TFPS fixation were significantly decreased from those of the intact spine in all modes and those of the stand-alone ALIF in flexion and extension. The TLFS and TFPS fixations significantly reduced NZs to below that of the intact spine in all modes. Compared with NZs for ALIF, both types of fixation revealed significantly lower values, except for TLFS placement in lateral bending and TFPS fixation in lateral bending and rotation. There were no significant differences between TLFS and TFPS fixation. There were also no significant differences among both TLFS and TFPS and TSR fixations, except that TFPS was inferior to TSR in lateral bending.

Conclusions. Stand-alone ALIF may not provide sufficient stability. Both facet fixations produced significant additional stability and both are comparable to TSR fixation. Although TFPS fixation revealed a slightly inferior result, TFPSs can be placed percutaneously with the assistance of fluoroscopic guidance and it makes the posterior facet fixation minimally invasive. Therefore, the TFPS fixation can be considered as a good alternative to TLFS fixation.
A biomechanical comparison of three surgical approaches in bilateral subaxial cervical facet dislocation
Authors: Kim Sung-Min , Lim T. Jesse , Paterno Josemaria , Park Jon , Kim Daniel H.
Published: May 2009

Object. In bilateral cervical facet dislocation, biomechanical stabilities between anterior locking screw/plate fixation after anterior cervical discectomy and fusion (ACDFP) and posterior transpedicular screw/rod fixation after anterior cervical discectomy and fusion (ACDFTP) have not been compared using the human cadaver, although ACDFP has been performed frequently. In this study the stability of ACDFP, a posterior wiring procedure after ACDFP (ACDFPW), and ACDFTP for treatment of bilateral cervical facet dislocation were compared.

Methods. Spines (C3—T1) from 10 human cadavers were tested in the intact state, and then after ACDFP, ACDFPW, and ACDFTP were performed. Intervertebral motion was measured using a video-based motion capture system. The range of motion (ROM) and neutral zone (NZ) were compared for each loading mode to a maximum of 2 Nm.

The ROM for spines treated with ACDFP was below that of the intact spine in all loading modes, with statistical significance in flexion and extension, but NZs were decreased in flexion and extension and slightly increased in bending and axial rotation; none of these showed statistical significance. The ACDFPW produced statistically significant additional stability in axial rotation ROM and in flexion NZ than ACDFP. The ACDFTP provided better stability than ACDFP in bending and axial rotation, and better stability than ACDFPW in bending for both ROM and NZ. There was no significant difference in extension with either ROM or NZ for the three fixation methods.

Conclusions. The spines treated with ACDFTP demonstrated the most effective stabilization, followed by those treated with ACDFPW, and then ACDFP. The spines receiving ACDFP also revealed a higher stability than the intact spine in most loading modes; thus ACDFP can also provide a relatively effective stabilization in bilateral cervical facet dislocation, but with the aid of a brace.
Cervical spinal cord delivery of a rabies G protein pseudotyped lentiviral vector in the SOD-1 transgenic mouse
Authors: Tanase Kiana , Teng Qingshan , Krishnaney Ajit A. , Liu James K. , Garrity-Moses Mary E. , Boulis Nicholas M.
Published: May 2009

Object. Lentiviral vectors may constitute a vehicle for long-term therapeutic gene expression in the spinal cord. In amyotrophic lateral sclerosis, spinal cord sclerosis and altered axonal transport pose barriers to therapeutic gene distribution. In the present study the authors characterize gene expression distribution and the behavioral impact of the rabies G (RabG) protein pseudotyped lentiviral vector EIAV.LacZ through cervical spinal cord injection in control and Cu/Zn superoxide dismutase—1 (SOD-1) transgenic mice.

Methods. Seven-week-old SOD-1 transgenic mice and their wild-type littermates underwent exposure of the cervicomedullary junction and microinjection of RabG.EIAV.LacZ or vehicle. The Basso-Beattie-Bresnahan locomotor score, grip strength meter, and Rotarod assays were used to assess the effects of disease progression, spinal cord microinjection, and lentiviral gene expression. Spinal cords were removed when the mice were in the terminal stage of the disease. The distribution of LacZ gene expression was histologically evaluated and quantified.

Direct cervical spinal cord microinjection of RabG.EIAV.LacZ results in extensive central nervous system uptake in SOD-1 transgenic mice; these findings were statistically similar to those in wild-type mice (p > 0.05). Gene expression lasts for the duration of the animal's survival (132 days). The SOD-1 mutation does not prevent retrograde axonal transport of the vector. Three behavioral assays were used to demonstrate that long-term gene expression does not alter sensorimotor function. In comparison with normative data, vector injection and transgene expression do not accelerate disease progression.

Conclusions. Direct spinal cord injection of RabG.EIAV vectors represents a feasible method for delivering therapeutic genes to upper cervical spinal cord and brainstem motor neurons. Distribution is not affected by the SOD-1 mutation or disease phenotype.
The future in the care of the cervical spine: interbody fusion and arthroplasty
Authors: Mummaneni Praveen V. , Haid Regis W.
Published: May 2009

✓ In the past 50 years tremendous advances have been made in the treatment of cervical disc disease with cervical fusion. Fusion rates have surpassed 95% after application of anterior cervical implants. Adjacent-segment degeneration, however, has plagued the long-term clinical success of cervical fusion.

Cervical arthroplasty has been introduced to maintain cervical motion and potentially avoid or minimize adjacent-segment degeneration. If cervical arthroplasty is successful, the long-term results of surgery for cervical disc disease may improve; however, there are associated drawbacks that must be overcome. Implant wear, fatigue, and failure have been reported in cases of large-joint arthroplasty, and research is underway to limit these problems in cervical arthroplasty.

In this article the authors trace the evolution of cervical fusion and the new technique of cervical arthroplasty. The nomenclature of cervical arthroplasty will also be introduced.
Does chronic cervical myelopathy affect respiratory function?
Authors: Toyoda Hiromitsu , Nakamura Hiroaki , Konishi Sadahiko , Terai Hidetomi , Takaoka Kunio
Published: May 2009

Object. Although respiratory function is often impaired by acute cervical spinal cord injury, changes in respiratory function in patients with chronic cervical myelopathy (CCM) are not well documented. The purpose of this study was to evaluate the respiratory function of patients with CCM.

Methods. Spirometric parameters were measured in 94 patients with CCM before they underwent expansive laminoplasty. These measurements were compared with those obtained in age- and sex-matched control group patients without myelopathy. The study patients were also subdivided into two groups: those with spinal compressive lesions above or below the C3–4 disc level were compared in terms of respiratory function.

The vital capacity values measured in patients with CCM were significantly lower than those in the control group. In patients in whom spinal cord compression was present above C3–4, vital capacity values were lower than in patients in whom the compression level was below C3–4. The resting respiratory rate per minute was elevated in the CCM group. Peak expiratory flow rate was significantly decreased, and expiratory velocities at 50 and 25% of vital capacity were significantly increased in the CCM group.

Conclusions. The results indicated that expiratory flow may be impaired or incomplete in patients with CCM. An underlying subclinical respiratory dysfunction appears to be associated with CCM.
Evaluation and treatment of congenital and developmental anomalies of the cervical spine
Authors: Menezes Arnold H.
Published: May 2009

✓ Congenital and developmental osseous abnormalities of the cervical spine can result in neural compression ranging from the medulla oblongata to the cervicothoracic spinal cord junction. These may present in infancy as scoliosis and even limb weakness. A high index of suspicion is essential. Neurodiagnostic imaging relies on high-resolution computerized tomography (CT) scanning and three-dimensional CT reconstructions as well as magnetic resonance imaging and angiography. The anatomical/physiological CT factors considered when developing a surgical approach are: 1) the stability and reducibility of the lesions; 2) direction and manner of encroachment of the lesion on the neural structures; 3) neural and vascular abnormalities; and 4) growth potential of the affected area. Primary stabilization is required for reducible lesions, whereas irreducible lesions are decompressed in the manner in which encroachment has occurred. Instability, whether present before or after operative intervention, required spinal stabilization. Illustrative examples of this approach are presented.
Insertion torque and pullout force of rescue screws for anterior cervical plate fixation in a fatigued initial pilot hole
Authors: Pitzen Tobias , Franta Frederick , Barbier Dragos , Steudel Wolf-Ingo
Published: May 2009

Object.The purpose of this study was to investigate whether thicker-core-diameter screws increase fixation strength in the cervical spine.

Methods.Bone mineral density (BMD) was determined for each vertebral body (VB) obtained in six human C4–7 segments. Based on their BMD, the specimens were assigned to one of two groups in which torque and pullout force were tested. Two initial pilot holes were drilled into the VBs and tests were first performed using a standard screw. The test was repeated using a thicker rescue screw inserted into the same initial pilot hole. The mean value of peak torque and pullout force resulting from the single left/right measurements was used for statistical analysis. A t-test was performed to determine the effect of screw design on peak torque and pullout force. Moment correlation coefficients were calculated to determine the effect of BMD on peak torque and pullout force.

Mean insertional peak torque for the standard screw was 82.1 N/cm and that for the rescue screw was 47.6 Ncm (p < 0.001). There was a strong correlation between insertional peak torque and BMD for both standard screws (r = 0.71, p = 0.02) and rescue screws (r = 0.59, p = 0.07). The mean pullout force for standard screws was 464.7 N, whereas it was 164.5 N for rescue screws (p < 0.001). There was a strong correlation between pullout force and BMD for both standard (r = 0.75, p = 0.0081) and rescue screws (r = 0.7, p = 0.025).

Conclusions.Uncemented rescue screws that have been inserted into a fatigued hole in the cervical VB do not strengthen the screw—bone interface compared with the strength initially conferred by a standard screw.