bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of genes for bone morphogenetic protein—4, —6, growth differentiation factor—5, and bone morphogenetic protein receptors in the process of experimental spondylosis in mice
Authors: Bunakase Takano , Ariga Kenta , Miyamoto Shimpei , Okuda Shin'ya , Tomita Tetsuya , Iwasaki Motoki , Yonenobu Kazuo , Yoshikawa Hideki
Published: May 2009

Object. Because little is known about the molecular mechanisms underlying the process of spondylosis, the authors examined the extent of genetic localization of several members of bone morphogenetic protein (BMP) and BMP receptors in chondrogenesis during the process of inducing spondylosis in their previously established experimental mice model.

Methods. Experimental spondylosis was induced in 5-week-old ICR mice. The cervical spine was harvested chronologically, and histological sections were prepared. Messenger RNA for BMP-4, growth and differentiation (GDF)—5, BMP-6, and BMP receptors (ALK-3, -6, and BMP-RII) was localized in the tissue sections by in situ hybridization.

In the early stage, BMP-4—derived mRNA was localized mainly in cells in the anterior margin of the cervical discs, together with ALK-6 and BMP-RII mRNA. No GDF-5 and BMP-6 mRNA was detected at this stage. In the late stage, cells positive for BMP-4 decreased, whereas GDF-5 and BMP-6 mRNA were localized in cells undergoing chondrogenesis. The ALK-3 mRNA began to appear in this stage, as did ALK-6 and BMP-RII.

Conclusions. The localization of transcripts for BMP-4, -6, and GDF-5 as well as BMP receptors shown during the present experimental model indicate the possible involvement of molecular signaling by these BMPs in the chondrogenic progress in spondylosis.
The effects of dexamethasone on bone fusion in an experimental model of posterolateral lumbar spinal arthrodesis
Authors: Sawin Paul D. , Dickman Curtis A. , Crawford Neil R. , Melton M. Stephen , Bichard William D. , Sonntag Volker K. H.
Published: May 2009

Object. The use of corticosteroid agents during the healing phase after spinal arthrodesis remains controversial. Although anecdotal opinion suggests that corticosteroids may inhibit bone fusion, such an effect has not been substantiated in clinical trials or laboratory investigations. This study was undertaken to delineate the effect of exogenous corticosteroid administration on bone graft incorporation in an experimental model of posterolateral lumbar fusion.

Methods. An established, well-validated model of lumbar intertransverse process spinal fusion in the rabbit was used. Twenty-four adult New Zealand white rabbits underwent L5–6 bilateral posterolateral spinal fusion in which autogenous iliac crest bone graft was used. After surgery, the animals were randomized into two treatment groups: a control group (12 rabbits) that received intramuscular injections of normal saline twice daily and a dexamethasone group (12 rabbits) that received intramuscular dexamethasone (0.05 mg/kg) twice daily. After 42 days, the animals were killed and the integrity of the spinal fusions was assessed by radiography, manual palpation, and biomechanical testing.

In seven (58%) of the 12 control rabbits, solid posterolateral fusion was achieved. In no dexamethasone-treated rabbits was successful fusion achieved (p = 0.003). Tensile strength and stiffness of excised spinal segments were significantly lower in dexamethasone-treated animals than in control animals (tensile strength 91.4 ± 30.6 N and 145.3 ± 48.2, respectively, p = 0.004; stiffness 31.4 ± 11.6 and 45.0 ± 15.2 N/mm, respectively, p = 0.02).

Conclusions. The corticosteroid agent dexamethasone inhibited bone graft incorporation in a rabbit model of single-level posterolateral lumbar spinal fusion, inducing a significantly higher rate of nonunion, compared with that in saline-treated control animals.
Innervation of caudal denervated ventral roots and their target muscles by the rostral spinal motoneurons after implanting a nerve autograft in spinal cord—injured adult marmosets
Authors: Liu Song , Aghakhani Nozar , Boisset Nazaire , Said Gérard , Tadie Marc
Published: May 2009

Object. The authors conducted a study to determine the effects of using a nerve autograft (NAG) to promote and guide axonal regrowth from the rostral spinal cord to the caudal lumbar ventral nerve roots to restore hindlimb motor function in adult marmosets after lower thoracic cord injury.

Methods. Nine animals underwent a left-sided hemisection of the spinal cord at T-12 via left-sided T9—L3 hemilaminectomy, with section of all ipsilateral lumbrosacral ventral nerve roots. In the experimental group (five animals), an NAG obtained from the right peroneal nerve was anastomosed with the sectioned and electrophysiologically selected lumbar ventral roots (left L-3 and L-4) controlling the left quadriceps muscle and then implanted into the left ventrolateral T-10 cord. In the control group (four animals), the sectioned/selected lumbar ventral roots were only ligated.

After surgery, all marmosets immediately suffered from complete paralysis of their left hindlimb. Five months later, some clinical signs of reinnervation such as tension and resistance began to appear in the paralyzed quadriceps of all experimental animals that received autografts. Nine months postoperatively, three of the five experimental marmosets could maintain their lesioned hindlimb in hip flexion. Muscle action potentials and motor evoked potentials were recorded from the target quadriceps in all experimental marmosets, but these potentials were absent in the control animals. Horseradish peroxidase retrograde labeling from the distal sectioned/reconnected lumbar ventral roots traced 234 ± 178 labeled neurons in the ipsilateral T8–10 ventral horn, mainly close to the NAG tip. Histological analysis showed numerous regenerating axons in this denervated/reconnected nerve root pathway, as well as newly formed motor endplates in the denervated/reinnervated quadriceps. No axonal regeneration was detected in the control animals.

Conclusions. These data indicate that the rostral spinal neurons can regrow into the caudal ventral roots through an NAG, thereby innervating the target muscle in adult marmosets after spinal cord injury.
Effects of hole preparation on screw pullout resistance and insertional torque: a biomechanical study
Authors: Öktenoǧlu B. Tunç , Ferrara Lisa A. , Andalkar Niteen , Özer A. Fahir , Sarioǧlu Ali Çetin , Benzel Edward C.
Published: May 2009

Object. The authors conducted a study to assess the effect of a pilot hole preparation on screw pullout resistance and screw insertional torque.

Methods. Three different screws were tested: cancellous lateral mass screws, cortical lateral mass screws, and pedicle screws. Synthetic bone blocks were used as the host material. Each screw group was separated into two subgroups. The first subgroup of screws was inserted into the test material following pilot hole preparation. Pilot holes were prepared; a drill bit diameter size smaller than the core diameter of the screws was used. The second group of screws was inserted into the test material without pilot hole preparation (a 3- or 4-mm hole drilled for entrance site preparation only). The insertional torque was measured as the screw was advanced into the material. The screws were axially extracted from the host material at a constant speed of 2.5 mm/minute. The pullout resistances and insertional torques for the pilot hole and the nonpilot hole groups were then statistically compared.

The authors found that preparation of a pilot hole caused a significant decrease in the insertional torque. The screws inserted without a pilot hole showed greater pullout resistances compared with those inserted following a pilot hole preparation; however, there was no statistically significant difference.

Conclusions. The optimum screw insertion technique may involve drilling a short pilot hole and using a drill bit with a smaller diameter than the screw core diameter to increase bone—screw purchase. This applies to cancellous and cortical lateral mass screws as well as pedicle screws.
Thoracic spine arachnoid ossification with and without cord cavitation
Authors: Mello Luis Renato , Bernardes Celso Itiberê , Feltrin Yanara , Rodacki Marco Antonio
Published: May 2009

✓ Thoracic spine arachnoid ossification is a relatively rare disease that affects mainly women and causes sensory, motor, and sphinctal symptoms associated with inferior limb pain. Based on three cases, the authors comment on pathogenic and surgery-related aspects of the disease. The patient in Case 1 was followed over the course of 23 years. Spinal cavitation is highlighted in Case 2, and yellow, gross, half-ring ossification is described in Case 3. Calcium deposits usually occur in the middle and lower thoracic spine where the majority of trabeculated arachnoid cells are located. Operative treatment does not interrupt the ossification process, which continues over time, causing progressive deterioration in the patient. Spinal cavitation can occur due to spinal cord tethering, stretching, and central cord edema formation, accompanied by cerebrospinal fluid blockage and pulse pressure changes. The results of surgical intervention are poor, offering short-term recovery with later deterioration. Multiple pathogenic factors are involved in this clinical syndrome including metabolic changes.
Microsurgical anterior cervical foraminotomy (uncinatectomy) for cervical disc herniation
Authors: Taşçioǧlu Al O. , Attar Ayhan , Taşçioǧlu Beliz
Published: May 2009

✓ The authors present the long-term follow-up results in three cases in which pure lateral disc herniations were surgically treated via an anterior foraminotomy (uncinatectomy) that avoided entering the disc space.

The pertinent anatomical details essential for a safe approach are discussed in light of nine cadaveric neck dissections of every segment between C-1 and C-7. The surgical technique was initially studied in the cadaveric specimens and then applied in patients.

The long-term results (> 2 years) in the first three patients are as good as our short-term results in another eight cases.
Intraspinal osteolipoma
Authors: Lin Ying-Chao , Huang Chao-Cheng , Chen Han-Jung
Published: May 2009

✓ Lipomatous tumors can contain uncommon or rare components (such as fibrolipoma or angiolipoma) that may result in the development of symptoms. To the best of the authors' knowledge, lipoma associated with an osseous component has not been previously reported. A case of intraspinal extradural tumor composed of both adipose and bone tissue is presented. Current theories on the cause of lipoma with an osseous component are discussed. The tumor was histologically confirmed to be an osteolipoma, and the patient recovered well after resection.
Cervical cord compression due to a hypoplastic atlas
Authors: May Daniel , Jenny Benoît , Faundez Antonio
Published: May 2009

✓ The authors report the case of a 66-year-old man with progressive, nontraumatic, C-1 cord compression who presented with a complete but hypoplastic atlas. They review six cases found in the literature. Symptoms usually develop in the late adulthood; the sagittal diameter of the canal measures 10 mm or less. The treatment requires a posterior decompression. Opening of the dura is sometimes necessary. There is no pressing need for a primary stabilization device.
Os odontoideum associated with hypertrophic ossiculum terminale
Authors: Sakaida Hiroshi , Waga Shiro , Kojima Tadashi , Kubo Yoshichika , Niwa Shigehiko , Matsubara Toshio
Published: May 2009

✓ The authors report on the case of a 20-year-old man who presented with a transient tetraparesis. Neuroimaging studies demonstrated atlantoaxial dislocation and ventral compression of the rostral spinal cord caused by a quite rare association of os odontoideum and hypertrophic ossiculum terminale. The patient underwent removal of two free ossicula via a transoral approach and posterior fusion in which an autogenous bone graft was placed.

The majority of cases of os odontoideum are believed to be an acquired form; however, controversy with regard to the congenital causes of os odontoideum remains. One hypothesis is that os odontoideum results from the failure of fusion and the hypertrophy of the proatlas, although considerable confusion surrounds this hypothesis because definitive classification of os odontoideum—to differentiate between similar anomalies—has not been established. This rare coincidence in the current case supports the belief that os odontoideum has a different embryological origin from ossiculum terminale, which is thought to be a proatlantal remnant.
Subluxation of a lumbar vertebra in a patient with Marfan syndrome
Authors: Domán István , Kövér Ferenc , Illés Tamás , Dóczi Tamás
Published: May 2009

✓ Marfan syndrome is a hereditary disorder of the connective tissue that, in its most classic form, includes cardiovascular, ocular, and skeletal features. The neurological problems associated with the disease are mainly caused by intracranial vascular abnormalities and spinal meningeal defects, but other neurological manifestations are rarely present. Scoliosis, a skeletal manifestation of the syndrome, occurs frequently, but its onset, natural history, and radiological characteristics differ from those of the idiopathic form. Scoliosis in a patient with Marfan syndrome seldom accompanies other spinal deformities. In this article the authors describe the case of a patient with Marfan syndrome and scoliosis in whom lumbar subluxation occurred. This rare deformity, diagnosed on three-dimensional computerized tomography scanning, has not been reported previously in association with Marfan syndrome. Its development can be explained in terms of the theory of progressive rotatory dislocation. The morphological characteristics, clinical features, and surgical treatment of the deformity are presented.
Complete familial Currarino triad
Authors: Kurosaki Masamichi , Kamitani Hideki , Anno Yuichi , Watanabe Takashi , Hori Tomokatsu , Yamasaki Tatsusuke
Published: May 2009

✓ The Currarino triad is a unique complex of congenital caudal anomalies including anorectal malformation, sacral bone abnormality, and presacral mass. In this report, the authors describe three cases with the complete Currarino triad in a family. The authors treated a 30-year-old mother with an anterior sacral meningocele, her 1-year-old son with a combination of anterior sacral meningocele and dermoid cyst, and her 4-year-old daughter with an epidermoid cyst. These three patients had associated sacral agenesis and anorectal malformations. To the authors' knowledge, this is the first report describing radiological and operative findings of complete familial Currarino triad in which a mother and her two children were affected.
Use of cylindrical titanium mesh and locking plates in anterior cervical fusion
Authors: Das Kaushik , Couldwell William T. , Sava Gerard , Tadonio Rudolph F.
Published: May 2009

✓ After performing anterior cervical corpectomy or discectomy for cervical spondolytic myelopathy or radiculopathy, iliac crest bone graft and fibular auto- or allograft is often used to achieve arthrodesis in the cervical spine. The purpose of this study was to evaluate the use of a cylindrical titanium mesh and locking plate system as an alternative technique in achieving anterior cervical fusion and maintaining lordosis.

Hospital records and radiographs of 38 patients who underwent anterior cervical discectomies (28 patients) or corpectomies (10 patients) from 1995 to 1997 were reviewed retrospectively. All patients had undergone arthrodesis in which autograft and a cylindrical titanium mesh and anterior locking plate fixation were used after discectomy or corpectomy. There were 20 men and 18 women (mean age 46.1 years; range 34–72 years). Presenting symptoms included radiculopathy (61%), myelopathy (37%), and neck pain (2%). Preoperative and postoperative radiographs were studied, and data were obtained on the following: overall lordosis or kyphosis of the cervical spine, segmental lordosis or kyphosis at each surgically treated level, and evidence of fusion.

In all of the patients in whom lordosis was present preoperatively, lordosis was maintained during the follow-up period. The overall fusion rate was 100%. The average change in overall lordosis or kyphosis related to the fixation devices was 1.2° (range 1–5°); the average segmental change was 2.3° (range 0–5°); and the mean follow up was 16 months (range 12–36 months).

Anterior cervical fusion with cylindrical titanium mesh and cervical locking plate system is an effective method of achieving arthrodesis and maintaining alignment in the cervical spine. The construct may provide additional load-sharing function, and it avoids the use of cadaveric bone or the need for harvesting tricortical iliac crest autograft.
Can airway complications following multilevel anterior cervical surgery be avoided?
Authors: Epstein Nancy E. , Hollingsworth Renee , Nardi Dominic , Singer Johnathan
Published: May 2009

Object. The authors conducted a study to determine how to avoid emergency postoperative reintubation and its associated morbidity in patients who have undergone multilevel anterior—posterior cervical spine surgery.

Methods. In a group effort between the departments of anesthesia and neurosurgery, a protocol was developed to avoid having to reintubate patients postoperatively. As a preventative measure, patients remained intubated overnight; on the 1st postoperative day or thereafter, based on direct fiberoptic visualization of reactive tracheal swelling, an anesthesiologist extubated the patients. Fifty-eight patients underwent multilevel anterior corpectomy with fusion (ACF; with 41 receiving plates and 17 not receiving plates), posterior wiring and fusion (PWF), and application of a halo. On average, ACF involved three levels, whereas PWF included 6.5 levels. Surgery typically lasted 10 hours, and an average 2.6 U of blood was required.

Forty patients were successfully extubated on the 1st, five on the 2nd, three on the 3rd, two on the 4th, two on the 5th, and three on the 7th postoperative day. Three elective tracheostomies were performed on the 7th postoperative day. Risk factors associated with delayed extubation or tracheostomy in 18 patients included: operative time longer than 10 hours (12 patients), obesity greater than 220 lbs (12 patients), transfusion of more than 4 U of blood (10 patients), ACF reoperations (nine patients), ACF including C-2 (seven patients), four-level ACF (five patients), and asthma (five patients). In the only case in which emergency reintubation was required, three risk factors were present.

Conclusions. Emergency reintubation following anterior—posterior cervical surgery and fusion can be avoided by maintaining intubation overnight and subsequently having an anesthesiologist remove the tube after healing is fiberoptically confirmed. Familiarity with major risk factors contributing to airway compromise, combined with this protocol, should minimize the significant morbidity associated with reintubation following multilevel anterior—posterior cervical fusion.
Clinical and radiological correlates of severity and surgery-related outcome in cervical spondylosis
Authors: Singh Anoushka , Crockard H. Alan , Platts Andrew , Stevens John
Published: May 2009

Object. The aim of this study was to determine if radiological features could be used to predict outcome in patients with cervical spondylotic myelopathy (CSM).

Methods. The authors studied 69 patients consecutively referred to The National Hospital, Queen Square, for decompressive surgery. Data obtained from preoperative cervical spine magnetic resonance (MR) imaging studies were each analyzed on two separate occasions by two blinded radiologists. The parameters determined were signal change and the presence and severity of compression. Clinical outcome was determined by pre- and postoperative timed walks, as well as by evaluation of myelopathy disability index scores, Ranawat classification, and Nurick grades.

There was good inter- and intraobserver reliability for determination of radiological data. A significant relationship was found between MR imaging signal change and surgery-related outcome, as reflected by improvement in walking parameters; however, this was confounded by the fact that signal change also related to preoperative walking parameters, and those patients for whom preoperative walking function was worse experienced greater functional improvement in walking postoperatively. The relationships between ambulatory-related data and severity or extent of spinal cord compression were less marked.

Conclusions. Cervical cord compression and intrinsic MR imaging signal change correlate with clinical severity, and, in this population, the presence of signal change was correlated with better surgery-related outcome. However, confounding factors and the lack of strong correlation indicate that these radiological measurements are insufficient to be used as a reliable tool for predicting surgery-related benefits in individual patients.
Presence and significance of CD-95 (Fas/APO1) expression after spinal cord injury
Authors: Zurita Mercedes , Vaquero Jesús , Zurita Isabel
Published: May 2009

Object. A glycoprotein, CD95 (Fas/APO1) is widely considered to be implicated in the development of apoptosis in a number of tissues. Based on the hypothesis that apoptosis is related to cell death after spinal cord injury (SCI), the authors studied the presence and distribution of CD95 (Fas/APO1)-positive cells in injured spinal cord tissue for the purpose of determining the significance of this protein during the early phases of SCI.

Methods. The presence and distribution of cells showing positive immunostaining for CD95 (Fas/APO1) were studied 1, 4, 8, 24, 48, and 72 hours and 1, 2, and 4 weeks after induction of experimental SCI in rats. Studies were conducted using a monoclonal antibody to the CD95 (Fas/APO1) protein. Positivity for CD95 (Fas/APO1) was observed in apoptotic cells, mainly in the gray matter, 1 hour after trauma, and the number of immunostained cells increased for the first 8 hours, at which time the protein was expressed in both gray and white matter. From 24 to 72 hours postinjury, the number of immunostained cells decreased in the gray matter, but increased in the white matter. From then on, there were fewer CD95 (Fas/APO1)-positive cells, but some cells in the white matter still exhibited positive immunostaining 1 and 2 weeks after injury. At 4 weeks, there remained no CD95 (Fas/APO1)-positive cells in injured spinal cord.

Conclusions. These findings indicate that CD95 (Fas/APO1) is expressed after SCI, suggesting a role for this protein in the development of apoptosis after trauma and the possibility of a new therapeutic approach to SCI based on blocking the CD95 (Fas/APO1) system.
Cervical spinal motion during intubation: efficacy of stabilization maneuvers in the setting of complete segmental instability
Authors: Lennarson Peter J. , Smith Darin W. , Sawin Paul D. , Todd Michael M. , Sato Yutaka , Traynelis Vincent C.
Published: May 2009

Object. The purpose of this study was to characterize and compare segmental cervical motion during orotracheal intubation in cadavers with and without a complete subaxial injury, as well as to examine the efficacy of commonly used stabilization techniques in limiting that motion.

Methods. Intubation procedures were performed in 10 fresh human cadavers in which cervical spines were intact and following the creation of a complete C4–5 ligamentous injury. Movement of the cervical spine during direct laryngoscopy and intubation was recorded using video fluoroscopy and examined under the following conditions: 1) without stabilization; 2) with manual in-line cervical immobilization; and 3) with Gardner—Wells traction. Subsequently, segmental angular rotation, subluxation, and distraction at the injured C4–5 level were measured from digitized frames of the recorded video fluoroscopy.

Conclusions: After complete C4–5 destabilization, the effects of attempted stabilization on distraction, angulation, and subluxation were analyzed. Immobilization effectively eliminated distraction, and diminished angulation, but increased subluxation. Traction significantly increased distraction, but decreased angular rotation and effectively eliminated subluxation. Orotracheal intubation without stabilization had intermediate results, causing less distraction than traction, less subluxation than immobilization, but increased angulation compared with either intervention.

These results are discussed in terms of both statistical and clinical significance and recommendations are made.
Occipital neuralgia secondary to hypermobile posterior arch of atlas
Authors: Post Alexander F. , Narayan Prithvi , Haid Regis W.
Published: May 2009

✓ The authors report on the management of occipital neuralgia secondary to an abnormality of the atlas in which the posterior arch was separated by a fibrous band from the lateral masses, resulting in C-2 nerve root compression. The causes and treatments of occipital neuralgia as well as the development of the atlas are reviewed.
Spinal stabilization by using crossed-screw anterior—posterior fixation after multisegmental total spondylectomy for thoracic chondrosarcoma
Authors: Doh Jae-Won , Halliday Andrea L. , Baldwin Nevan G. , Benzel Edward C.
Published: May 2009

✓ The authors describe the case of a 41-year-old man with high-grade chondrosarcoma who presented with a paraspinous mass extending into three thoracic vertebrae (T10–12). Crossfixed long anterior and posterior instrumentation was placed after three complete spondylectomies (T10–12). This technique augments spinal stability with an outrigger effect by using crossfixators placed between paired dorsal rods, as well as between the anterior and posterior hardware components. This technique may be used as an alternative when multiple vertebrae or all three spinal columns are involved by radioresistant malignant tumors in patients in whom there is a relatively long life expectancy.
En bloc removal of the lower lumbar vertebral body for chordoma
Authors: Bosma Jark J. D. , Pigott Timothy J. D. , Pennie Bruce H. , Jaffray David C.
Published: May 2009

✓ En bloc removal of the lower lumbar vertebral bodies (VBs) is a major surgical challenge. The authors describe the surgical technique used in two patients who presented with chordoma confined to the L-5 and L-4 VB, respectively. These tumors were diagnosed using magnetic resonance (MR) imaging during investigation for back pain.

Both patients underwent a combined (two-stage) anterior—posterior approach. In the first case the posterior stage of the procedure was followed by an anterior retroperitoneal approach, and in the second case a lateral retroperitoneal approach was used.

Complete en bloc excision of the tumor was achieved in each case, even though in the second case the VB fractured when it was mobilized. The correlation between the MR imaging findings and surgical specimens was remarkable.

The authors conclude that en bloc resection is feasible in these cases. Because mobilization of the VB is more difficult in the lateral approach, the authors favor the anterior retroperitoneal approach.

The authors anticipate the need for such procedures to increase with the widespread use of MR imaging, which demonstrates the extent of these tumors with remarkable accuracy.
Bilateral posterolateral approach to mirror-image C-2 neurofibromas
Authors: Bartolomei Juan C. , Crockard H. Alan
Published: May 2009

✓ Multiple nerve root tumors are usually present in patients afflicted with neurofibromatosis Type 1. Although rare, upper cervical mirror-image neurofibromas have been reported in the medical literature, and their surgical management has been addressed in several reports; however, little has been mentioned or is known regarding upper cervical or craniocervical stability following resection of these tumors. In this report the authors describe four cases of large mirror-image C-2 neurofibromas resected in two stages via the posterolateral approach. One patient presented with acute neurological deterioration after a biopsy sample had been obtained, whereas the other three presented with gradual onset of lower-extremity weakness over several months. The time interval between the first and second decompressive surgery ranged from 10 days to 12 weeks. There were no surgery-related complications, and all patients recovered motor function in their extremities. During a follow-up period of 16 to 36 months, there was no clinical or radiological evidence of upper cervical spine instability. Although the series is too small to draw any definitive conclusions, in the authors' experience the posterolateral approach provides a direct route for the successful surgical treatment of bilateral craniocervical nerve root tumors without destabilizing the upper cervical segments.
Intramedullary neurenteric cysts of the spine
Authors: Lippman Caleb R. , Arginteanu Marc , Purohit Dushayant , Naidich Thomas P. , Camins Martin B.
Published: May 2009

✓ This case of a 68-year-old woman with a low-thoracic intramedullary neurenteric cyst is notable for clinical presentation, cyst location, intraoperative findings, and imaging characteristics. The patient's postoperative course was complicated by neurological deterioration and a neuropathic pain syndrome. Potential causes of these complications are discussed, as are possible ways to reduce the risk of their occurrence.
Oncocytoma of the spinal cord
Authors: Kim Se Hoon , Paik Soya , Yoon Do Heum , Kim Tai Seung
Published: May 2009

✓ The authors report a case of oncocytoma arising from the spinal cord in a 40-year-old woman who presented with the complaints of gradual difficulty in walking. The excised tumor was exclusively composed of polygonal cells with abundant homogeneous eosinophilic cytoplasms. Electron microscopy study showed densely packed swollen mitochondria and frequent desmosomes. The histological and ultrastructural findings were consistent with a diagnosis of oncocytoma. To the authors' knowledge, this represents the first reported case of oncocytoma of the spinal cord.
Acute posttraumatic spinal cord herniation
Authors: Marquardt Gerhard , Weidauer Stefan , Zanella Friedhelm E. , Seifert Volker
Published: May 2009

✓ Transdural herniations of the spinal cord are rare, and those occurring acutely after a spinal cord injury (SCI) are particularly unusual. In this report, the authors present the case of acute posttraumatic spinal cord herniation in a patient who sustained severe polytraumatic injuries. The clinical manifestations were acute flaccid paralysis of the right leg and rapidly progressive sensorimotor deficits of the contralateral leg. The herniation was surgically reduced. Postoperatively left leg paralysis was completely resolved. The authors review the pertinent literature, and suggest that, with regard to another underlying pathophysiological mechanism, cases of acute posttraumatic spinal cord herniation should be differentiated from those “posttraumatic” cases in which herniation of the spinal cord occurs years or even decades after the traumatic event. To the best of the authors' knowledge, only one similar case has been previously reported. They conclude that acute posttraumatic spinal cord herniation should be included in the differential diagnosis of acute neurological deterioration after SCI.
Use of a guide device to place pedicle screws in the thoracic spine: a cadaveric study
Authors: Jang Jee Soo , Lee Won Bok , Yuan Hansen A.
Published: May 2009

✓ In this cadaveric study, the safety and accuracy of a specially designed guide device for the placement of thoracic pedicle screws was investigated in a normal anatomical situation.

Five embalmed human cadaveric thoracic spines (T1–12) were used for the study of transpedicular screw placement in the thoracic spine. Overall 120 screws were placed at all thoracic levels. The screws were inserted bilaterally in the thoracic pedicles by using a specially designed guide device. No radiographs or other imaging studies were obtained. Following screw placement, computerized tomography scans were performed to evaluate the accuracy of the pedicle screw positioning.

Seven (5.8%) of the screws penetrated the pedicle wall or the vertebral body (VB) cortex. Two screws (1.7%) penetrated the medial wall of the pedicle. Two screws (1.7%) penetrated the lateral wall of the pedicle, and one screw (0.8%) penetrated the lateral wall of the pedicle and the anterior VB cortex simultaneously. Two screws (1.7%) penetrated the anterior VB cortex.

Compared with the results of other studies, the findings here indicate that using this device to guide the placement of thoracic pedicle screws can significantly reduce the incidence of pedicle penetration, particularly in the medial wall.
Threaded cortical bone dowels for lumbar interbody fusion: over 1-year mean follow up in 28 patients
Authors: Barnes Bryan , Rodts Gerald E. , McLaughlin Mark R. , Haid Regis W.
Published: May 2009

Object. The authors retrospectively reviewed a series of 35 patients with mechanical low-back or one- to two-level discogenic pain; the patients underwent lumbar interbody fusion in which threaded cortical bone dowels (TCBDs) were placed to treat degenerative disc disease. The purpose of the study was to delineate fusion rates and outcome data in this series of patients.

Methods. The series was composed of 18 women and 17 men whose mean age was 46 years (range 17–76 years). There were nine active cigarette smokers. All patients presented with symptoms consistent with mechanical low-back or discogenic pain, and magnetic resonance imaging revealed degenerative changes related to disc collapse at one or two vertebral levels. For placement of the TCBDs, 23 patients underwent posterior lumbar interbody fusion (PLIF), whereas 12 patients underwent anterior lumbar interbody fusion (ALIF). In all except one patient undergoing PLIF, pedicle screw and rod constructs were used without posterolateral fusion. In all patients undergoing ALIF except one, TCBDs were used as stand-alone devices without supplemental fixation. At follow up the success of fusion was determined by static lumbar radiography and/or computerized tomography scanning. The degree of lumbar lordosis at the diseased level was measured immediately postoperatively and compared with that documented on follow-up radiological studies. Outcomes were assessed using a modified Prolo Scale. Excellent and good outcomes were considered satisfactory, and fair or poor outcomes were considered unsatisfactory.

In 28 patients (eight ALIF and 20 PLIF) radiological and clinical follow-up data were considered adequate. The mean follow-up duration was 12.3 months. Overall satisfactory outcome was 60%; 70% satisfactory outcome was noted in PLIF patients and 38% in ALIF patients. Osseous fusion was present in 95% of the patients in the PLIF group and in 13% of those in the ALIF group. Complications included one L-5 nerve root injury and two postoperative wound infections, all in patients who underwent PLIF; in an ALIF patient lateral breakout of one implant occurred at 8 months postoperatively.

Conclusions. Analysis of the mean 12.3 month follow-up data indicates that there is a dramatically higher fusion rate in PLIF compared with ALIF procedures when TCBDs are used. The authors believe that it is important to note that in all the PLIF procedures except one, supplemental pedicle screw/rod constructs were used, whereas in ALIF procedures no supplemental fixation was performed. The results thus suggest that TCBDs are best used in PLIF in conjunction with pedicle screw and rod constructs.
Adjacent-segment morbidity after Graf ligamentoplasty compared with posterolateral lumbar fusion
Authors: Kanayama Masahiro , Hashimoto Tomoyuki , Shigenobu Keiichi , Harada Masahito , Oha Fumihiro , Ohkoshi Yasumitsu , Tada Hiroshi , Yamamoto Kazuki , Yamane Shigeru
Published: May 2009

Object. Of concern to spine surgeons are accelerated degenerative changes of motion segments located above and below where spinal fusion has been performed. Graf artificial ligament stabilization has been developed to avoid the adverse effect of spinal fusion. The object of this study was to assess the adjacent-segment morbidity of Graf ligamentoplasty compared with posterolateral fusion (PF) in which instrumentation was used.

Methods. Data obtained in 45 patients who underwent L4–5 Graf ligamentoplasty (18 patients) or PF with instrumentation (27 patients) were reviewed retrospectively. The minimum follow-up period was 5 years. In the PF group a solid fusion rate of 92.6% was achieved. Radiographic evaluation included assessment of lumbar sagittal alignment, range of motion (ROM), and adjacent-disc degeneration. Adjacent-segment morbidity was clinically assessed by determining the reoperation rate.

Graf ligamentoplasty maintained regional lordosis and flexibility (13° in L4–5 lordosis; 4.4° in L4–5 ROM). Although there was no difference in preoperative adjacent-disc condition between the two groups, radiographic evidence of adjacent-disc deterioration was observed more frequently in patients in the PF group than the Graf group (25% and 6% at L1–2; 38% and 6% at L2–3; 38% and 18% at L3–4; and 43% and 18% at L5—sacrum, respectively). One case in the Graf group (5.6%) and five cases in the PF group (18.5%) required additional surgeries for adjacent-segment lesions.

Conclusions. Graf ligamentoplasty cannot completely replace spinal fusion. In a well-selected group of patients, however, it was shown to maintain lumbar mobility and sagittal alignment, and it decreased the risk of adjacent-segment deterioration compared with PF with instrumentation.
Management of complex pediatric and adolescent spinal deformity
Authors: Wiggins Gregory C. , Rauzzino Michael J. , Bartkowski Henry M. , Nockels Russ P. , Shaffrey Christopher I.
Published: May 2009

Object. The authors sought to analyze prospectively the outcome of surgery for complex spinal deformity in the pediatric and young adult populations.

Methods. The authors evaluate all pediatric and adolescent patients undergoing operative correction of complex spinal deformity from December 1997 through July 1999. No patient was lost to follow-up review (average 21.1 months). There were 27 consecutive pediatric and adolescent patients (3–20 years of age) who underwent 32 operations. Diagnoses included scoliosis (18 idiopathic, five nonidiopathic) and four severe kyphoscoliosis. Operative correction and arthrodesis were achieved via 21 posterior approaches (Cotrel-Dubousset-Horizon), seven anterior approaches (Isola or Kaneda Scoliosis System), and two combined approaches. Operative time averaged 358 minutes (range 115–620 minutes). Blood loss averaged 807 ml (range 100–2000 ml). Levels treated averaged 9.1 (range three–16 levels). There was a 54% average Cobb angle correction (range 6–82%). No case was complicated by the patient's neurological deterioration, loss of somatosensory evoked potential monitoring, cardiopulmonary disease, donor-site complication, or wound breakdown. There was one case of hook failure and one progression of deformity beyond the site of surgical instrumentation that required reoperation. There were 10 minor complications that did not significantly affect patient outcome. No patient received undirected banked blood products. There was a significant improvement in cosmesis, and no patient experienced continued pain postoperatively. All patients have been able to return to their preoperative activities.

Conclusions. Compared with other major neurosurgical operations, segmental instrumentation for pediatric and adolescent spinal deformity is a safe procedure with minimal morbidity and there is a low risk of needing to use allogeneic blood products.
Tarlov cysts: a study of 10 cases with review of the literature
Authors: Voyadzis Jean-Marc , Bhargava Parul , Henderson Fraser C.
Published: May 2009

Object. Tarlov or perineurial cysts are lesions of the nerve root most often found in the sacral region. Although there is agreement that asymptomatic Tarlov cysts should be followed, it is still debated whether patients with symptomatic Tarlov cysts should be treated surgically. The authors assessed the outcome and efficacy of cyst wall resection in 10 patients with symptomatic Tarlov cysts. The medical literature is reviewed, theories of origin are evaluated, and suggestions as to their cause and pathogenesis are offered.

Methods. Ten consecutive patients harboring symptomatic Tarlov cysts were treated by the senior author between 1989 and 1999. All patients were assessed for neurological deficits and pain by neurological examination and visual analog scale, respectively. Computerized tomography myelography was performed in all patients to diagnose delayed filling of the cysts. A sacral laminectomy with resection of the sacral cyst or cysts was performed in all patients. Resected material from eight of 10 patients was submitted for histopathological evaluation. Seven (70%) of 10 patients obtained complete or substantial resolution of their symptoms, with an average follow up of 31.7 months. All of these patients had Tarlov cysts larger than 1.5 cm in diameter, producing radicular pain or bladder and bowel dysfunction. Three (30%) of 10 patients experienced no significant improvement. All three patients harbored Tarlov cysts smaller than 1.5 cm in diameter, producing nonradicular pain. Histopathological examination was performed on specimens from eight of 10 patients, which demonstrated nerve fibers in 75% of cases, ganglion cells in 25% of cases, and evidence of old hemorrhage in half.

Conclusions. Large cysts (> 1.5 cm) and the presence of associated radicular symptoms strongly correlate with excellent outcome. Tarlov cysts may result from increased hydrostatic pressure and trauma.
Microendoscopic posterior cervical laminoforaminotomy for unilateral radiculopathy: results of a new technique in 100 cases
Authors: Adamson Tim E.
Published: May 2009

Object. In this report the author presents surgery-related outcomes after application of a new technique. A posterior microendoscopic laminoforaminotomy was used for the surgical treatment of unilateral cervical radiculopathy secondary to intervertebral disc herniations and/or spondylotic foraminal stenosis. The results of this procedure are compared with those achieved using traditional laminoforaminotomy and anterior cervical discectomy with or without fusion.

Methods. One hundred consecutive patients who experienced unilateral cervical radicular syndromes, which were refractory to conservative therapy, and in whom imaging studies had confirmed lateral canal or foraminal compression, underwent surgical treatment. An endoscopy-assisted posterior laminoforaminotomy was performed using a microendoscopic visualization system for removal of herniated disc and foraminal decompression while the patient was in the sitting position.

Excellent or good results were obtained in 97 patients, who returned to their preoperative employment and baseline level of physical activity. One patient returned to work but was unable to perform at baseline level; two patients returned to prior sedentary work but continued to have some activity-related pain and paresthesias. Two patients reported experiencing intermittent paresthesias or numbness, but this did not limit their activities. There were two cases of dural punctures, one case of superficial wound infection, and no deaths.

Conclusions. The microendoscopic posterior laminoforaminotomy is an effective alternative for the treatment of unilateral cervical radiculopathy secondary to lateral or foraminal disc herniations or spondylosis. In this group of patients, it is preferable because it does not require the sacrifice of a cervical motion segment, has a low incidence of complications, and is associated with a much quicker return to unrestricted full activity than that obtained with other techniques.
Screw placement in transoral atlantoaxial plating systems: an anatomical study
Authors: Kandziora Frank , Schulze-Stahl Niels , Khodadadyan-Klostermann Cyrus , Schröder Ralf , Mittlmeier Thomas
Published: May 2009

Object. The placement of an anterior atlantoaxial plate after transoral odontoid resection has been described by Harms. Recently, the authors of biomechanical and clinical studies have shown that this procedure, especially in combination with posterior wiring, is a good alternative to established, isolated posterior atlantoaxial fixation techniques. Reports on the anatomy of the atlas and axis primarily focus on the posterior surgical approach. Scarce research regarding the quantitative anatomy of the anterior aspect of C-1 and C-2 has been reported. This study was undertaken to measure relevant dimensions of C-1 and C-2 and their relation to the anterior transoral approach. The aim of the study was to determine “safe zones” for screw placement in anterior atlantoaxial plate fixation.

Method. Fifty human dry C-1 and C-2 vertebrae were obtained for direct anatomical, radiographic, and computerized tomography (CT) measurements. Thirty-two linear and four angular parameters were evaluated. All measurements were made using a digital caliper, ruler, or goniometer. Anatomical measurements were correlated with radiographic (anteroposterior, lateral, and craniocaudal) and CT (0.5-mm-slice thickness) measurements of the corresponding vertebrae. Additionally, bone mineral density (BMD) measurements of C-1 and C-2 were obtained in 20 patients.

A safe zone for anterior screw placement in an atlas of bilateral trapezoid shape could be characterized. The average medial and lateral height of the trapezoid was 4.1 ± 1.01 mm (range 1.4–6.7 mm) and 12.9 ± 1.73 mm (range 8.7–17.4 mm), respectively. The distance between the sagittal plane and the medial and lateral walls of the trapezoid was 10.2 ± 1.42 mm (range 8.9–12.8 mm) and 23.5 ± 2.98 mm (range 21.7–30.7 mm), respectively. The average depth of the lateral masses was 22.3 ± 2.04 mm (range 17.0–26.7 mm) in the sagittal plane. The average BMD in the safe zone of C-1 was 0.89 ± 0.11 g/cm3 (range 0.75–1.01 g/cm3). Bone mineral density measurements at C-2 revealed a spheroid zone of low density at the basis of the dens (0.68 ± 0.09 g/cm3). In contrast, high zones of BMD were found near the articular surfaces (C1–2: 0.97 ± 0.11 g/cm3; C2–3: 0.94 ± 0.12 g/cm3). The safe zone for anterior axis screw placement was V-shaped, limited cranially by a zone of low bone density and laterally by the vertebral artery groove. Correlations between radiographic and anatomical measurements were generally good (r2 = 0.78–0.95), but they were higher between CT and anatomical measurements (r2 = 0.86–0.99).

Conclusions. A quantitative understanding of the anterior anatomy of C-1 and C-2 is necessary when considering anterior atlantoaxial plate fixation after transoral odontoid resection. In this study the authors defined safe zones for anterior atlas and axis screw placement. The anterior atlantoaxial plate, as originally described by Harms, only partially respects these safe zones.